JP3577172B2 - Flame retardant photopolymerizable composition and flame retardant adhesive tape using the same - Google Patents

Description

【００１４】
上記化合物（ｃ）の具体例として、アクリロイロキシホスフェート、アクリロイロキシ（ジメチル）ホスフェート、アクリロイロキシ（ジエチル）ホスフェート、アクリロイロキシ（ジフェニル）ホスフェート、アクリロイロキシメチルホスフェート、アクリロイロキシメチル（ジメチル）ホスフェート、アクリロイロキシメチル（ジエチル）ホスフェート、アクリロイロキシエチルホスフェート、アクリロイロキシエチル（ジメチル）ホスフェート、アクリロイロキシエチル（ジエチル）ホスフェート、アクリロイロキシヘキシルホスフェート、アクリロイロキシオクチルホスフェート、アクリロイロキシフェニルホスフェート等が挙げられる。
【００１５】
請求項２記載の発明は、請求項１記載の（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）と共重合可能であり、且つ、分子内にリン元素を有する化合物が上記構造式（Ｉ）もしくは（ＩＩ）で表される化合物である難燃性光重合性組成物をその要旨とするものである。
【００１６】
上記化合物（ｃ）は、上記（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）の混合物１００重量部に対し、３〜２０重量部の範囲ので含有される。
上記含有量が３重量部未満の場合、得られるアクリル系共重合体の難燃性が必要性能を満たさず、且つ、凝集力及び耐クリープ性も充分に与えられない。 又、２０重量部を超えると、凝集力が高過ぎ、且つ、剥離強度が低下する。
【００１７】
上記光重合開始剤（ｄ）としては、特に限定されるものではないが、例えば、４−（２−ヒドロキシエトキシ）フェニル（２−ヒドロキシ−２−プロピル）ケトン（チバガイギー社製、商品名「イルガキュア２９５９」）等のケトン系；α−ヒドロキシ−α，α’−ジメチル−アセトフェノン（チバガイギー社製、商品名「ダロキュア１１７３」）、メトキシアセトフェノン、２，２−ジメトキシ−２−フェニルアセトフェノン（チバガイギー社製、商品名「イルガキュア６５１」）、２−ヒドロキシ−２−シクロヘキシルアセトフェノン（チバガイギー社製、商品名「イルガキュア１８４」）等のアセトフェノン系；ベンジルジメチルケタール等のケタール系；その他、ハロゲン化ケトン、アシルホスフィノキシド、アシルホスフォナート等を挙げることができる。
【００１８】
上記光重合開始剤（ｄ）の含有量は、上記（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）の混合物１００重量部に対し、０．０１〜５重量部、好ましくは０．０５〜３重量部である。光重合開始剤（ｄ）の含有量が、０．０１重量部未満の場合、重合反応が進行しにくいため、十分な転化率が得られず、５重量部を超える場合、ラジカル発生量が多くなり過ぎ、低分子量の共重合体しか得られない。
【００１９】
本発明に用いられるフィラーとしては、上記のように繊維状フィラー（ｅ１）、多孔質微粒子（ｅ２）、非極性樹脂微粒子（ｅ３）、有機微粒子（ｅ４）、偏平状微粒子（ｅ５）、微粒子（ｅ６）、シリカ系微粒子（ｅ７）、シリカ系微粒子（ｅ８）および微粒子（ｅ９）が挙げられる。
【００２０】
上記繊維状フィラー（ｅ１）としては、ガラス繊維、セピオライト系繊維、クリソタイル系繊維、ウオラストナイト、ＰＭＦ（Ｐｒｏｃｅｓｓｅｄ Ｍｉｎｅｒａｌ Ｆｉｂｅｒ）、ゾノトライト、チタン酸カリ等が挙げられるが、安全環境上の問題から、クリソタイル等のアスベスト系繊維は避けるべきである。本発明の難燃性光重合性組成物には、上記繊維状フィラーのうち、平均直径が０．２〜２０μｍであり、且つ、平均繊維長が５μｍ〜１ｍｍのフィラーが用いられる。上記繊維状フィラーの平均直径が０．２μｍ未満の場合、得られる難燃性粘着テープの剪断強度が不十分となり、２０μｍを超える場合、平滑な表面を有する難燃性粘着テープが得られない。繊維状フィラーの平均繊維長が５μｍ未満の場合、得られる難燃性粘着テープの剪断強度が不十分となり、１ｍｍを超える場合、平滑な表面を有する難燃性粘着性テープが得られない。
【００２１】
上記繊維状フィラー（ｅ１）の含有量は、上記（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）の混合物１００重量部に対し、０．５〜２０重量部であることが好ましく、更に好ましくは２〜１５重量部である。繊維状フィラー（ｅ１）の含有量が、モノマー混合物１００重量部に対して０．５重量部未満の場合、得られる難燃性粘着テープの剪断強度が不十分となり、２０重量部を超える場合、得られる難燃性光重合性組成物の粘度が著しく高くなり、平滑な表面を有する難燃性粘着テープが得られない。
【００２２】
上記多孔質微粒子（ｅ２）としては、ケイソウ土等の天然無機微粒子、シリカゲル等の合成無機微粒子、多孔質処理をした有機微粒子等がある。本発明の難燃性光重合性組成物には、上記多孔質微粒子のうち、平均粒子径が０．５〜１５０μｍの微粒子が用いられる。上記多孔質微粒子の平均粒子径が０．５μｍ未満の場合、得られる難燃性粘着テープの剥離強度が不十分となり、１５０μｍを超える場合には、難燃性粘着テープの剪断強度が不十分となる。
【００２３】
上記多孔質微粒子（ｅ２）の含有量は、上記（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）の混合物１００重量部に対し、０．５〜２０重量部であることが好ましく、更に好ましくは２〜１５重量部である。多孔質微粒子（ｅ２）の含有量が、モノマー混合物１００重量部に対して０．５重量部未満の場合、得られる難燃性粘着テープの接着強度が不十分となり、２０重量部を超える場合、得られる難燃性光重合性組成物の粘度が著しく高くなり、平滑な表面を有する難燃性粘着テープが得られない。
【００２４】
上記非極性樹脂微粒子（ｅ３）としては、低密度ポリエチレン（ＬＤＰＥ）、直鎖状低密度ポリエチレン（Ｌ−ＬＤＰＥ）、高密度ポリエチレン（ＨＤＰＥ）などのポリエチレン微粒子；ポリプロピレン微粒子；ジメチルシリコーン等のシリコーン微粒子等が挙げられる。本発明の難燃性光重合性組成物には、上記非極性樹脂微粒子のうち、平均粒子径が５〜１５０μｍの微粒子が用いられる。上記非極性樹脂微粒子の平均粒子径が５μｍ未満の場合、得られる難燃性粘着テープの剥離強度が不十分となり、１５０μｍを超える場合には、得られる難燃性粘着テープの剪断強度が不十分となる。
【００２５】
上記非極性樹脂微粒子（ｅ３）の含有量は、上記（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）の混合物１００重量部に対して８〜７０重量部であることが好ましく、更に好ましくは１０〜６０重量部である。非極性樹脂微粒子（ｅ３）の含有量が、モノマー混合物１００重量部に対して８重量部未満の場合、得られる難燃性粘着テープの接着強度が不十分となり、７０重量部を超える場合、得られる難燃性光重合性組成物の光透過率が低くなり、重合反応速度が著しく低下する。
【００２６】
上記有機微粒子（ｅ４）としては、ポリメチルメタクリレート、ポリスチレンなど、又はこれらを主成分とする共重合体が挙げられ、その共重合体は架橋されていることが好ましい。上記有機微粒子は又、フェノール樹脂、グアナミン樹脂等の熱硬化性樹脂であってもよい。本発明の難燃性光重合性組成物には、上記有機微粒子のうち、平均粒子径が５〜１００μｍであり、且つ、ガラス転移温度が９０℃以上である微粒子が用いられる。上記有機微粒子の平均粒子径が５μｍ未満の場合、得られる難燃性粘着テープの剥離強度が不十分となり、１００μｍを超える場合、得られる難燃性粘着テープの剪断強度が不十分となる。又、上記有機微粒子のガラス転移温度が９０℃未満の場合には、得られる難燃性粘着テープの高温での接着強度が不十分となる。
【００２７】
上記有機微粒子（ｅ４）の含有量は、上記（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）の混合物１００重量部に対して５〜５０重量部であることが好ましく、更に好ましくは１０〜４０重量部である。有機微粒子（ｅ４）の含有量が、モノマー混合物１００重量部に対して５重量部未満の場合、得られる難燃性粘着性テープの接着強度が不十分となり、５０重量部を超える場合、得られる難燃性光重合性組成物の粘度が著しく高くなり、平滑な表面を有する難燃性粘着テープを得ることができない。
【００２８】
上記偏平状微粒子（ｅ５）としては、例えば、微粉カリ・フッ素雲母、微粉ナトリウム・フッ素雲母等の合成雲母等が挙げられる。マスコバイト、フロゴパイトのようなケイ酸アルミニウム系化合物であって、通常マイカと呼ばれる化合物を用いることもできるが、マイカは着色の度合が強く、光の透過を阻害するため、光照射により重合を行う場合には好ましくない。即ち、本発明においては、光透過性の高い合成雲母を用いることが好ましい。本発明の難燃性光重合性組成物には、上記偏平状微粒子のうち、平均粒子径が１〜５０μｍであり、且つ、アスペクト比が２０〜４０である微粒子が用いられる。上記偏平状微粒子の平均粒子径が１μｍ未満の場合、得られる難燃性粘着テープの剥離強度が不十分となり、５０μｍを超える場合には、難燃性粘着テープの剪断強度が不十分となる。上記偏平状微粒子のアスペクト比が２０未満の場合、得られる難燃性粘着テープの剪断強度が不十分となり、４０を超える場合、平滑な表面を有する難燃性粘着テープを得ることができない。
【００２９】
上記偏平状微粒子（ｅ５）の含有量は、上記（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）の混合物１００重量部に対して１〜２０重量部であることが好ましく、更に好ましくは３〜１５重量部である。上記偏平状微粒子（ｅ５）の含有量が、モノマー混合物１００重量部に対して１重量部未満の場合、得られる難燃性粘着テープの接着強度が不十分となり、２０重量部を超える場合、得られる難燃性光重合性組成物の粘度が著しく高くなり、平滑な表面を有する難燃性粘着テープを得ることができない。
【００３０】
上記アルミノシリケート化合物を主成分とする微粒子（ｅ６）としては、例えば、アルミナとケイ酸塩とから合成されるものや、発電所などから排出されるフライアッシュ等がある。上記微粒子（ｅ６）は中空微粒子であってもよく、このような中空微粒子としては、シラスバルーン、フラシアッシュバルーン等がある。シラスバルーンは、九州に大量に存在するシラス土壌（火山灰）を焼成発泡させたものであり、市販品としては、イチジ化成社製のウインライト（商品名）、昭和化学工業社製のスーパーバルーン（商品名）等がある。フライアッシュバルーンは、主に発電所から排出される軽質灰であり、市販品としては、英国フィライト社製のフィライト（商品名）、小野田セメント社製のマイクロセルズ（商品名）、ＰＱコーポレーション製のエクステンドスフェア（商品名）等がある。
【００３１】
本発明の難燃性光重合性組成物には、上記微粒子（ｅ６）のうち平均粒子径が１〜１５０μｍである微粒子が用いられる。上記微粒子（ｅ６）の平均粒子径が１μｍ未満の場合、得られる難燃性粘着テープの剥離強度が不十分となり、１５０μｍを超える場合、難燃性粘着テープの剪断強度が不十分となる。
【００３２】
上記微粒子（ｅ６）の含有量は、上記（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）の混合物１００重量部に対して１〜４０重量部であることが好ましく、更に好ましくは３〜３０重量部である。上記微粒子（ｅ６）の含有量が、モノマー混合物１００重量部に対して１重量部未満の場合、得られる難燃性粘着テープの接着強度が不十分となり、４０重量部を超える場合、得られる難燃性光重合性組成物の光透過率が低くなり、重合反応が著しく遅くなる。
【００３３】
上記シリカ系微粒子（ｅ７）としては、アルカリガラス、ホウケイ酸系ガラスのようにＳｉＯ_２ を約５０〜約７０重量％含有するガラス類；ＳｉＯ_２ を９８重量％以上含有するシリカ類；Ａｌ_２ Ｏ_３ とＳｉＯ_２ とを主成分とするアルミノシリケート類などを原料とする微粒子及びそれらの微粒子の表面に疎水化処理を施した微粒子が挙げられる。本発明の難燃性光重合性組成物には、上記微粒子のうち、平均粒子径が１０〜１５０μｍであり、且つ、表面が平滑である微粒子が用いられる。上記微粒子の１０μｍ未満の場合、得られる難燃性粘着テープの剥離強度が不十分となり、１５０μｍを超える場合、難燃性粘着テープの剪断強度が不十分となる。又、該シリカ系微粒子の表面が平滑であることにより、難燃性光重合性組成物中に含まれるシリカ系微粒子とモノマー混合物との接触面積が小さくなり、難燃性光重合性組成物の粘度が上昇しにくい。そのため難燃性粘着テープを製造する際の難燃性光重合性組成物の塗工を容易に行うことができる。
【００３４】
上記シリカ系微粒子（ｅ７）の含有量は、上記（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）の混合物１００重量部に対して５０〜１７５重量部であることが好ましく、更に好ましくは７０〜１５０重量部である。上記シリカ系微粒子（ｅ７）の含有量が、５０重量部未満の場合、得られる難燃性粘着テープの剥離強度が不十分となり、１７５重量部を超える場合、難燃性粘着テープの剪断強度が不十分となる。
【００３５】
上記粒子表面が疎水化処理されたシリカ系微粒子（ｅ８）としては、アルカリガラス、ホウケイ酸系ガラス等のガラス類；ＳｉＯ_２ を９８重量％以上含有するような石英、シリカゲル等；ガラスバルーン；シラスバルーン等がある。疎水化処理を行うには、ポリジメチルシロキサン、トリメトキシオクチルシラン、ヘキサメチルシラザン、トリメトキシステアリルシラン等のシランカップリング剤を用いることが好ましい。このように微粒子表面を疎水化処理することにより、この微粒子（ｅ８）と微粒子を取り巻くアクリル系共重合体との界面接着力が向上するため、該難燃性光重合性組成物を用いて得られる難燃性粘着テープは、接着強度に優れている。
【００３６】
本発明の難燃性光重合性組成物には、上記微粒子のうち、平均粒子径が１０〜１５０μｍである微粒子が用いられる。上記微粒子の１０μｍ未満の場合、得られる難燃性粘着性テープの剥離強度が不十分となり、１５０μｍを超える場合、難燃性粘着テープの剪断強度が不十分となる。
【００３７】
上記シリカ系微粒子（ｅ８）は、得られる難燃性光重合性組成物の全体積中の１５〜５０体積％を占める割合となるように含有されることが好ましい。上記シリカ系微粒子（ｅ８）の含有量が、得られる難燃性光重合性組成物の全体積中の１０体積％を占める割合未満の場合、得られる難燃性粘着テープの剥離強度が不十分となり、５０体積％を占める割合を超える場合には、難燃性粘着テープの剪断強度が不十分となる。微粒子（ｅ８）のうち、中空構造を有しない微粒子の比重は約２．１である。微粒子（ｅ８）として中空微粒子を用いる場合、比重が０．１５〜１．１の微粒子が好適に使用される。従って、上記シリカ系微粒子（ｅ８）の含有量を重量部に換算すると、上記（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）の混合物１００重量部に対して２〜１７５重量部であることが好ましく、更に好ましくは３〜１５０重量部である。
【００３８】
上記微粒子（ｅ９）としては、ポリメチルメタクリレート、ポリエチルアクリレート、ポリブチルメタクリレート、ウレタンエラストマー等の有機微粒子；シリカ微粒子等が挙げられる。有機微粒子を用いる場合、耐熱性を向上させるために、有機微粒子を構成するポリマーは架橋されていることが好ましい。本発明の難燃性光重合性組成物には、上記微粒子のうち、平均粒子径が５〜１５０μｍであり、且つ、屈折率が１．４７〜１．５１である微粒子が用いられる。上記微粒子の平均粒子径が５μｍ未満の場合、得られる難燃性粘着テープの剥離強度が不十分となり、１５０μｍを超える場合、難燃性粘着テープの剪断強度が不十分となる。上記微粒子の屈折率が１．４７〜１．５１の範囲外の場合、この微粒子（ｅ９）を含有する難燃性光重合性組成物を用いて得られる難燃性粘着テープの透明性が不十分となる。上記微粒子（ｅ９）が中空微粒子であることは好ましくない。何故ならば、中空微粒子の殻の屈折率が１．４７〜１．５１の範囲内であっても、該殻と内部との界面で反射してしまい、透明性が失われるためである。
【００３９】
上記微粒子（ｅ９）は、得られる難燃性光重合性組成物の全体積中の１５〜５０体積％を占める割合となるように含有されることが好ましく、更に好ましくは２０〜４０体積％を占める割合となるように含有される。上記微粒子（ｅ９）の含有量が、得られる難燃性光重合性組成物の全体積中の１５体積％を占める割合未満の場合、得られる難燃性粘着テープの接着強度が不十分となり、５０体積％を占める割合を超える場合、難燃性粘着テープの透明性が不十分となる。
【００４０】
本発明の難燃性光重合性組成物は、上記（メタ）アクリル酸エステルモノマー（ａ）、モノマー（ｂ）、分子内にリン元素を有する化合物（ｃ）、光重合開始剤（ｄ）、および上記フィラー（ｅ１）〜（ｅ９）のいずれか一種を、常法に従って、均一に攪拌しながら混合することにより得ることができる。
【００４１】
本発明の難燃性光重合性組成物には、耐熱性を向上するために、酢酸ビニル、プロピオン酸ビニル、イソボルニル（メタ）アクリレート等の０℃以上のＴｇを有するモノマーを必要に応じて配合してもよい。本発明の難燃性光重合性組成物には又、粘着付与樹脂（ＴＦ）を配合することもできる。好適なＴＦとしては、ロジン系樹脂、変性ロジン系樹脂、テルペン系樹脂、テルペンフェノール系樹脂、Ｃ５およびＣ９系石油樹脂、クマロン樹脂等、及びこれらの水添物などが挙げられ、これらは単独または２種以上を組み合わせて使用することができる。ただし、上記０℃以上のＴｇを有するモノマー及び／又は上記ＴＦを難燃性光重合性組成物に配合して重合する場合、重合速度が低下したり、分子量が低下したりする場合があるので、このような場合には、連鎖移動剤や上記分子内にリン元素を有する化合物（ｃ）の配合量を適宜調整することが好ましい。
【００４２】
上記連鎖移動剤は、共重合体の分子量を調節するために用いられ、例えば、ｎ−ドデシルメルカプタン、ｔ−ドデシルメルカプタン等が挙げられる。これらの連鎖移動剤は、上記（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）の混合物１００重量部に対し、０．０１〜０．１重量部の範囲で用いられ得る。
【００４３】
本発明の難燃性粘着テープを製造するには、先ず、得られる難燃性粘着テープの表面が平滑になるように、配合されているフィラーが均一に分散されるように難燃性光重合組成物を十分に攪拌増粘し、チキソ性を付与する。この難燃性光重合性組成物を離型処理した紙又はポリエチレンテレフタレート（ＰＥＴ）フィルム上に所定の厚さになるように塗工し、次いでその塗工面を光照射することにより難燃性粘着テープを得ることができる。
【００４４】
上記難燃性粘着テープは、５０μｍ〜５ｍｍの範囲の厚みに形成することができる。厚みが１００μｍ以下の粘着テープを製造する場合、粘度が１０００ｃｐｓ程度であり、チキソトロピー性を示すチキソトロピックインデックス（ＴＩ）値が１．５程度の難燃性光重合性組成物を用いて塗工することができるが、厚さが１００μｍを超える粘着テープを製造する場合には、上記難燃性光重合性組成物を更に高粘度にすることが好ましい。
【００４５】
難燃性光重合性組成物を高粘度にする手段としては、アクリルゴム、ニトリルゴム、スチレン−イソプレン−スチレンブロック（ＳＩＳ）等のジブロック又はトリブロックゴム等のエラストマー；ポリメチルメタクリレート（ＰＭＭＡ）、ポリスチレン（ＰＳｔ）等の熱可塑性プラスチック等を溶解してもよいし、平均粒子径が５μｍ以下のシリカ粒子、アルミナ粒子等を上記難燃性光重合性組成物に混合してもよい。上記添加物のうち無機物を添加する場合、より早く一次粒子まで分散することができるという点から、表面が疎水化処理を施されている粒子を用いることが好ましい。高粘度にするための他の方法として、上記のような添加物を加えず、上記難燃性光重合性組成物の一部を予め部分重合する方法がある。この部分重合は、分子内にリン元素を有する化合物（ｃ）を添加する以前に行い、ミクロゲル生成を防ぐべきである。部分的にミクロゲルが生成した場合には、塗工時に、スジ等の発生の原因となる。部分重合されるモノマーは、全モノマーの１．５重量％〜６０重量％にすべきである。部分重合されるモノマーが１．５重量％未満の場合、必要な粘度を得ることができず、６０重量％を超える場合、得られる難燃性光重合性組成物の粘度が高くなり過ぎて塗工できなくなる。
【００４６】
上記のようにして基材上に塗工した難燃性光重合性組成物に光を照射するには、以下に示す条件を用いて行われる。
【００４７】
光照射には、光波長４００ｎｍ以下に発光分布を有するランプ類が用いられる。このようなランプ類としては、低圧水銀灯、中圧水銀灯、高圧水銀灯、超高圧水銀灯、ケミカルランプ、ブラックライトランプ、マイクロウエーブ励起水銀灯、メタルハライドランプ等が挙げられる。この中でも、ケミカルランプは、開始剤の活性波長領域の光を効率よく発光し、開始剤以外の組成物はこの波長領域の光をあまり吸収しないため、難燃性光重合性組成物の内部まで光が透過し、高厚膜のシートを製造するのに好ましい。上記ランプの光照射強度は、得られるポリマーの重合度を左右する因子であり、目的製品の性能毎に適宜制御される。例えば、通常用いられるアセトフェノン基を有する開裂型の開始剤を配合した場合には、その開始剤の光分解に有効な波長領域（開始剤によって異なるが、通常、３６５ｎｍ〜４２０ｎｍの光が用いられる）の光が照射され、その光照射強度は、０．１〜１００ｍＷ／ｃｍ^２ の範囲であることが好ましい。
【００４８】
本発明における光重合は、空気中の酸素および難燃性光重合性組成物に溶解している酸素によって反応が阻害される。このため、光照射は、酸素の阻害されないような手法を用いて実施されなければならない。このような手法としては、表面を離型処理したポリエチレンテレフタレート（ＰＥＴ）やテフロン等のフィルムで、塗工された難燃性光重合性組成物を覆い、このフィルムを介して該難燃性光重合性組成物へ光を照射する方法がある。或いは、窒素ガス、炭酸ガス等のような不活性なガスで酸素を置換したイナートゾーンの中で光透過性の窓を介して外部より光照射して反応させる方法もある。イナートゾーンの中で反応させる方法において、該難燃性光重合性組成物の重合転化率を９９．７％以上とするためには、この照射雰囲気の酸素濃度は５０００ｐｐｍ以下であることが好ましく、より好ましくは３００ｐｐｍ以下である。
【００４９】
急速に光重合反応が進行する場合には、重合熱により、塗工される離型処理フィルムや、カバー用離型処理フィルムが加熱伸縮され、得られる難燃性粘着テープにスジなどが発生する場合がある。このようなスジの発生は、光カットフィルターによりランプからの輻射熱を抑制したり、照射面の反対側の背面を冷却板と接触させることにより冷却することで防ぐことができる。
【００５０】
本発明の難燃性粘着テープは、上記のように本発明の難燃性光重合性組成物を光重合により硬化させることにより得られる。この光重合によって得られる架橋体のガラス転移温度（Ｔｇ）が５０℃以下である場合には、この架橋体からなる難燃性粘着テープは、接合作業時にドライヤー等で僅かに加熱するだけで接着力を発現する感熱型の難燃性粘着テープとなる。光重合によって得られる架橋体のＴｇが２０℃以下である場合には、常温で粘着性のある難燃性粘着テープが得られる。雰囲気温度が０℃以下となるような冬場の現場作業性を重視する場合には、Ｔｇを５℃以下となるように設定すべきである。上記難燃性粘着テープの接着強度は、重合によって得られる架橋体のＴｇによらず、本発明のようにフィラーを配合することにより向上することができる。
【００５１】
本発明の難燃性粘着テープは、又、上記自粘性の難燃性粘着テープの片面又は両面に、更に粘着剤層を積層することにより作成することができる。新たに積層される粘着剤層を構成する粘着剤としては、アクリル系、ゴム系、シリコーン系等の粘着剤を使用することができ、それらの粘着剤は溶剤型、水分散型、ホットメルト型のいずれのタイプであってもかまわない。表面に光重合性組成物を塗布して光照射を行うことにより積層してもよい（以下、光重合型という）。用いる粘着剤が、ホットメルト型又は光重合型の場合、基材となる上記難燃性粘着テープ上に直接塗工し、積層することができる。用いる粘着剤が、溶剤型または水分散型の場合には、離型処理を施したフィルム上に該粘着剤を塗工し、乾燥して粘着剤層を形成し、その後、基材となる上記難燃性粘着テープ上に、該粘着剤層を転写積層する方法が用いられる。基材となる上記難燃性粘着テープ上に直接、溶剤型または水分散型の粘着剤を塗工すると、溶剤や水分が上記難燃性粘着テープ中に拡散し、それを乾燥するために長時間を要する場合がある。
【００５２】
上記粘着剤の組成および配合は、被着体に応じて変更するべきである。例えば、被着体がポリエチレンや、ポリプロピレンのようなポリオレフィン系の場合には、粘着付与樹脂を２０〜３５重量％配合したアクリル系粘着剤又は天然ゴム系粘着剤を用いることが好ましい。被着体が軟質塩化ビニル樹脂の場合には、極性成分として、Ｎ−ビニルピロリドン、Ｎ−ビニルカプロラクタム、アクリロイルモルホリン等を含有し、（メタ）アクリル酸等のカルボキシル基を含有しないアクリル系粘着剤組成物を使用すると、耐熱性に優れた粘着テープを得ることができる。
【００５３】
難燃性粘着テープの製造に用いられる難燃性光重合性組成物に、各種フィラーを配合することにより、得られる難燃性粘着テープの物性が向上する。例えば、繊維状フィラー（ｅ１）、非極性樹脂微粒子（ｅ３）、有機微粒子（ｅ４）、偏平状微粒子（ｅ５）、シリカ系微粒子（ｅ７）及び微粒子（ｅ９）を配合することにより、得られる難燃性粘着テープの接着強度が向上する。接着強度が向上する理由は必ずしも明らかではないが、特定組成のアクリル系架橋体中に、特定の微粒子を配合することにより弾性率が上昇し、剪断強度が向上することが推定される。
【００５４】
本発明の難燃性光重合性組成物は、叙上の如く構成されており、特に分子内にリン元素を有する化合物（ｃ）が（メタ）アクリル酸エステルモノマー（ａ）及びモノマー（ｂ）と共重合され、主材となるアクリル系共重合体を構成しているので、僅かな量の分子内にリン元素を有する化合物（ｃ）の共重合によって高い難燃性が長期間安定して保持され、これらを用いて得られる請求項３及び請求項４記載の発明の難燃性粘着テープは、いずれも高い難燃性を示し、且つ、該難燃性粘着テープの製造に用いられる難燃性光重合性組成物に、繊維状フィラー（ｅ１）；多孔質表面を有する微粒子（例えば、多孔質粒子（ｅ２））；シラノール基などの極性基を表面に有する微粒子（例えば、アルミノシリケート化合物を主成分とする微粒子（ｅ６））；又は、表面が疎水化処理された微粒子（例えば、シリカ系微粒子（ｅ８））をフィラーとして配合する場合には、フィラーの体積当たりの表面積が比較的大きく、接着面積が増大するため、より少量のフィラーで接着強度の優れた難燃性粘着テープを得ることができると考えられる。
【００５５】
微粒子（ｅ９）を配合する難燃性光重合性組成物を用いて製造された難燃性粘着テープを基材とし、これに、アクリル系粘着剤層を積層して難燃性粘着テープを製造した場合、この微粒子（ｅ９）の屈折率（１．４７〜１．５１の範囲）が、アクリル系粘着剤の屈折率に近いため、得られる難燃性粘着テープは透明性に優れている。
【００５６】
【発明の実施の形態】
以下に、実施例を用いて本発明を詳しく説明する。
【００５７】
（実施例１）
冷却管、温度計及び攪拌器を備えたセパラブルフラスコに、２−エチルヘキシルアクリレート９００ｇ、アクリル酸１００ｇ、イルガキュア１８４（チバガイギー社製、商品名）０．３ｇ及びセピオライト系繊維（水沢化学工業社製、商品名「エードプラスＳＰ」、平均直径：０．２μｍ、平均繊維長：７．５μｍ）１００ｇを仕込み、均一に分散するまで、攪拌混合した後、窒素ガスパージにより、溶存酸素を除去した。次いで、上記組成物にブラックライトランプを用いて紫外線を照射したところ、組成物の温度が上昇すると同時に粘度が高くなった。組成物の温度が５℃上昇したところで、光照射を止めた（この組成物を部分光重合増粘組成物という）。得られた部分光重合増粘組成物の転化率は４．１％、粘度は２３００ｃｐｓであった。
【００５８】
更にこの部分光重合増粘組成物にアクリロイロキシホスフェート（共栄化学社製、商品名「ライトエステルＰＡ」）１８０ｇを配合し、図１に示すように、離型処理した３８μｍの厚みのポリエチレンテレフタレートフィルム（ＰＥＴフィルム）１上に、重合終了時の厚みが１．０±０．１ｍｍとなるようにこの組成物を塗工し、更に同じＰＥＴフィルム１’を用いて、その離型処理面が塗工面に接するように塗工面をカバーした。
【００５９】
次いで、ケミカルランプを用いてこのカバーに用いたＰＥＴフィルム１’上の照射強度が２ｍＷ／ｃｍ^２ となるようにランプ高さを調整し、８分間照射して難燃性粘着シート２ａを得た。得られた難燃性粘着シート２ａの残存モノマーは０．１％、ゲル分率は８６％であった。
【００６０】
（実施例２）
イソノニルアクリレート９５０ｇ、アクリル酸１０ｇ、Ｎ−ビニルピロリドン４０ｇ及び親水性シリカ（日本アエロジル社製、商品名「アエロジル２００」）４０ｇをデイスパーで４時間にわたって１０００ｒｐｍで攪拌混合し、粘稠な液体を得た。これに、「イルガキュア１８４」０．３ｇ及び「ライトエステルＰＡ」を１２０ｇ加え、均一になるまで攪拌混合した後、窒素ガスをパージし、溶存する酸素を除去した。以下の工程は実施例１と同様にして厚さ１ｍｍの難燃性粘着シートを得た。
【００６１】
（実施例３）
２−エチルヘキシルアクリレート７００ｇ、イソオクチルアクリレート２００ｇ、アクリル酸１００ｇ及び疎水性シリカ（日本アエロジル社製、商品名「アエロジルＲ９７６」）７０ｇを、デイスパーで１０００ｒｐｍで３０分間攪拌混合し、粘稠な液体を得た。これに表面を疎水化処理したガラス繊維（フィラーとして用いた）（旭ファイバーグラス社製、商品名「ミルドファイバーＴ１０」、平均直径：１３μｍ、平均繊維長：２００μｍ）１００ｇ、「ライトエステルＰＡ」８０ｇ及び「イルガキュア６５１」（チバガイギー社製、商品名）０．３ｇを加え、均一になるまで攪拌混合した後、窒素ガスをパージし、溶存する酸素を除去した。以下の工程は実施例１と同様にして厚み約１ｍｍの難燃性粘着シートを得た。
【００６２】
（実施例４）
セピオライト系繊維１００ｇの代わりに、平均粒子径７５μｍの多孔質シリカゲル（水沢化学工業社製、商品名「シルビードＤ−ＭＳ１０００」）１００ｇをフィラーとして用いたこと以外は、実施例１と同様にして部分光重合増粘組成物を得た。得られた部分光重合増粘組成物の転化率は４．１％、粘度は２３００ｃｐｓであった。以下の工程は実施例１と同様にして難燃性粘着シートを得た。得られた難燃性粘着シートの残存モノマーは０．１％未満であり、ゲル分率は８５％であった。
【００６３】
（実施例５）
疎水化処理したガラス繊維１００ｇの代わりに、平均粒子径２５μｍの中空多孔質シリカ微粒子（鈴木油脂工業社製、商品名「ゴッドボールＢ−２５Ｃ」）５０ｇをフィラーとして用いたこと以外は、実施例３と同様にして難燃性光重合性組成物を得た。以下の工程は実施例３と同様にして難燃性粘着シートを得た。
【００６４】
（実施例６）
疎水化処理したガラス繊維１００ｇの代わりに、平均粒子径が０．７μｍの沈降性シリカ（水沢化学工業社製、商品名「ミズカシルＰ−５２７Ｕ」）１００ｇをフィラーとして用いたこと以外は、実施例３と同様にして難燃性光重合性組成物を得た。以下の工程は実施例３と同様にして難燃性粘着シートを得た。
【００６５】
（実施例７）
セピオライト系繊維１００ｇの代わりに、低密度ポリエチレン微粒子（住友精化社製、商品名「フローセンＵＦ４」、平均粒子径：２５μｍ）６００ｇをフィラーとして用いたこと以外は、実施例１と同様にして部分光重合増粘組成物を得た。得られた部分光重合増粘組成物の転化率は４．１％、粘度は２３００ｃｐｓであった。以下の工程は実施例１と同様にして難燃性粘着シートを得た。得られた難燃性粘着シートの残存モノマーは０．１％、ゲル分率は８０％であった。
【００６６】
（実施例８）
疎水化処理したガラス繊維１００ｇの代わりに、シリコーン微粒子（東レ・ダウコーニング・シリコーン社製、商品名「トレフィルＥ−６００」、平均粒子径：５μｍ）２００ｇをフィラーとして用いたこと以外は、実施例３と同様にして難燃性光重合性組成物を得た。以下の工程は実施例３と同様にして難燃性粘着シートを得た。
【００６７】
（実施例９）
疎水化処理したガラス繊維１００ｇの代わりに、高密度ポリエチレン微粒子（三井石油化学社製、商品名「ミペロンＸＭ−２２０」、平均粒子径：２０μｍ）５００ｇをフィラーとして用いたこと以外は、実施例３と同様にして難燃性光重合性組成物を得た。以下の工程は実施例３と同様にして難燃性粘着シートを得た。
【００６８】
（実施例１０）
セピオライト系繊維１００ｇの代わりに、平均粒子径４０μｍのポリメチルメタクリレート（ＰＭＭＡ）架橋体微粒子（積水化成品工業社製、商品名「テクポリマーＭＢＸ−４０」）５００ｇをフィラーとして用いたこと以外は、実施例１と同様にして部分光重合増粘組成物を得た。得られた組成物の転化率は４．８％、粘度は２５００ｃｐｓであった。以下の工程は実施例１と同様にして難燃性粘着シートを得た。得られた難燃性粘着シートの残存モノマーは０．１％未満であり、ゲル分率は８５％であった。
【００６９】
（実施例１１）
ガラス繊維１００ｇの代わりに、平均粒子径２０μｍのポリスチレン架橋体微粒子（積水化成品工業社製、商品名「テクポリマーＳＢＸ−２０」）２００ｇをフィラーとして用いたこと以外は、実施例２と同様にして光重合性組成物を得た。以下の工程は実施例２と同様にして難燃性粘着シートを得た。
【００７０】
（実施例１２）
セピオライト系繊維１００ｇの代わりに、平均粒子径３μｍの雲母（コープケミカル社製、商品名「合成雲母ＭＫ−１００」、アスペクト比：３０）５０ｇをフィラーとして用いたこと以外は、実施例１と同様にして部分光重合増粘組成物を得た。以下の工程は実施例１と同様にして難燃性粘着シートを得た。得られた難燃性粘着シートの残存モノマーは０．１％未満であり、ゲル分率は８３％であった。
【００７１】
（実施例１３）
セピオライト系繊維１００ｇの代わりに、平均粒子径４５μｍであり、且つ、ＳｉＯ_２ 約６０重量％およびＡｌ_２ Ｏ_３ 約３８重量％を含有するフライアッシュバルーン（小野田セメント社製、商品名「マイクロセルズＳＬ７５」）３００ｇをフィラーとして用いたこと以外は、実施例１と同様にして部分光重合増粘組成物を得た。得られた部分光重合増粘組成物の転化率は４．１％、粘度は２３００ｃｐｓであった。以下の工程は実施例１と同様にして難燃性粘着シートを得た。得られた難燃性粘着シートの残存モノマーは０．１％未満であり、ゲル分率は８５％であった。
【００７２】
（実施例１４）
ガラス繊維１００ｇの代わりに、平均粒子径４０μｍであり、且つ、ＳｉＯ_２ 約７５重量％及びＡｌ_２ Ｏ_３ 約１５重量％を含有するシラスバルーン（イチジ化成社製、商品名「ウインライトＳＣ−５０」）２００ｇをフィラーとして用いたこと以外は、実施例２と同様にして難燃性光重合性組成物を得た。以下の工程は実施例２と同様にして難燃性粘着シートを得た。
【００７３】
（実施例１５）
疎水化処理したガラス繊維１００ｇの代わりに、平均粒子径２．４μｍであり、且つ、ＳｉＯ_２ 約４８重量％及びＡｌ_２ Ｏ_３ 約４０重量％を含有するアルミノシリケート系微粒子（水沢化学工業社製、商品名「シルトンＡＭＴ２５」）１００ｇをフィラーとして用いたこと以外は、実施例３と同様にして光重合性組成物を得た。以下の工程は実施例３と同様にして難燃性粘着シートを得た。
【００７４】
（実施例１６）
セピオライト系繊維１００ｇの代わりに、ガラスビーズ（東芝バロティーニ社製、商品名「ＥＧＢ７３１」、平均粒子径：２５μｍ）１０００ｇをフィラーとして用いたこと以外は、実施例１と同様にして部分光重合増粘組成物を得た。以下の工程は実施例１と同様にして難燃性粘着シートを得た。得られた難燃性粘着シートの残存モノマーは０．１％、ゲル分率は８４％であった。
【００７５】
（実施例１７）
ガラス繊維１００ｇの代わりに、シリカビーズ（洞海化学社製、商品名「Ｍ．Ｓ．ＧＥＬ Ｄ−５０−０Ａ」、平均粒子径：５０μｍ）１０００ｇをフィラーとして用いたこと以外は、実施例２と同様にして難燃性光重合性組成物を得た。以下の工程は実施例２と同様にして難燃性粘着シートを得た。
【００７６】
（実施例１８）
疎水化処理したガラス繊維１００ｇの代わりに、表面を疎水化処理したガラスビーズ（東芝バロティーニ社製、商品名「ＥＧＢ７３１Ｎ」、平均粒子径：２０μｍ）１０００ｇをフィラーとして用いたこと以外は、実施例３と同様にして難燃性光重合性組成物を得た。以下の工程は実施例３と同様にして難燃性粘着シートを得た。
【００７７】
（実施例１９）
疎水化処理されたガラス繊維１００ｇの代わりに、平均粒子径６０μｍの中空ガラス微粒子（旭硝子社製、商品名「セルスターＺ−２７」、比重０．２７）の表面をポリジメチルシロキサン処理したもの５０ｇをフィラーとして用いたこと以外は、実施例３と同様にして難燃性光重合性組成物を得た。以下の工程は実施例３と同様にして難燃性粘着シートを得た。
【００７８】
（比較例１）
繊維状フィラーを含有させなかったこと以外は実施例１と同様にして難燃性光重合性組成物を得た。得られた難燃性光重合性組成物の転化率は５．１％、粘度は４１００ｃｐｓであった。この難燃性光重合性組成物を用いて実施例１と同様にして難燃性粘着シートを得た。
【００７９】
（比較例２）
「ライトエステルＰＡ」を含有させなかったこと以外は実施例１と同様にして光重合性組成物を得た。このようにして得られた組成物の転化率は４．１％であり、そして粘度は２３００ｃｐｓであった。この組成物を用いて実施例１と同様にして粘着シートを得た。
【００８０】
上記実施例１〜１９及び比較例１〜２で得られた難燃性粘着テープの難燃性、剪断強度及びＴ剥離強度について、以下に示す方法により測定した。測定結果は表１に示す。
【００８１】
＜剪断強度＞
図２に示すように、幅２０ｍｍ×長さ２０ｍｍの上記粘着シート２ａの粘着面を、プライマー表面処理したポリカーボネート板３（幅２５ｍｍ×長さ１０ｍｍ×厚み２ｍｍ）に貼り合わせ、２４時間室温にて放置て試験片を作成し、この試験片を用いて剪断強度を測定した。引張速度は、５０ｍｍ／分で行った。
【００８２】
＜Ｔ剥離強度＞
図３に示すように、幅２０ｍｍ×長さ７０ｍｍの上記粘着シート２ａの両面に、プライマー表面処理した厚み３００μｍのアルミ箔４を貼り付け、室温で２４時間放置して試験片を作成し、この試験片を用いてＴ剥離強度を測定した。引張速度は、２００ｍｍ／分で行った。
【００８３】
＜難燃性＞
難燃性の評価は、ＪＩＳ Ｄ １２０１に準拠して燃焼性の区分を行った。
【００８４】
【表１】

【００８５】
（実施例２０）
冷却管、温度計及び攪拌器を備えたセパラブルフラスコに、２−エチルヘキシルアクリレート２００ｇ、ｎ−ブチルアクリレート７００ｇ、Ｎ−ビニルピロリドン１００ｇ、２−ヒドロキシエチルメタクリレート２ｇ、ｎ−ドデカンチオール２ｇ及び酢酸エチル９００ｇを仕込み、窒素ガス雰囲気下で、還流するまで昇温し、２０分間保持した後、ベンジルペルオキシド１ｇを酢酸エチル１００ｇに溶解した溶液を滴下し、４時間反応させた。その後、ベンジルペルオキシド１ｇを酢酸エチル１００ｇに溶解した溶液を滴下し、さらに３時間反応させた。次いで、トルエン４００ｇを攪拌混合して、粘度１２０００ｃｐｓの粘着剤溶液（Ａ）を得た。固形分は３９．５重量％であった。
【００８６】
この粘着剤溶液（Ａ）１００ｇにイソシアネート系硬化剤（日本ポリウレタン社製、商品名：コロネートＬ５５Ｅ）を４．０ｇ加え、十分混合した後、脱泡し、離型処理したＰＥＴフィルム１上に塗工し、厚み４０μｍの粘着剤層を形成した。その後、上記粘着剤層を直ちに実施例１で得られた難燃性粘着シートの一方の面に、ホットラミネートし、図４で示されるような難燃性粘着シートを得た。
【００８７】
（比較例３）
実施例１で得られた難燃性粘着シートの代わりに、比較例１で得られた難燃性粘着シートを用いたこと以外は、実施例２０と同様にして難燃性粘着シートを得た。
尚、得られた難燃性粘着シートの性能を評価するための試験片は、図６に示すように、比較例１で得られた難燃性粘着シート２ｂの一方の粘着面に、軟質塩化ビニル樹脂６をラミネートし、難燃性粘着シート２ｂの他方の粘着面に、ポリカーボネート板３を貼り合わせて作成された。
【００８８】
（実施例２１）
実施例１で得られた難燃性粘着シートの代わりに、実施例４で得られた難燃性粘着シートを用いたこと以外は、実施例２０と同様にして粘着剤を塗工して難燃性粘着シートを得た。
【００８９】
（実施例２２）
実施例１で得られた難燃性粘着シートの代わりに、実施例７で得られた難燃性粘着シートを用いたこと以外は、実施例２０と同様にして難燃性粘着シートに粘着剤層をホットラミネートし、難燃性粘着シートを得た。
【００９０】
（実施例２３）
実施例１で得られた難燃性粘着シートの代わりに、実施例１０で得られた難燃性粘着シートを用いたこと以外は、実施例２０と同様にして粘着剤層をラミネートし、難燃性粘着テープを得た。
【００９１】
（実施例２４）
実施例１で得られた難燃性粘着シートの代わりに、実施例１２で得られた難燃性粘着シートを用いたこと以外は、実施例２０と同様にして粘着剤層をラミネートして難燃性粘着シートを得た。
【００９２】
（実施例２５）
実施例１で得られた難燃性粘着シートの代わりに、実施例１３で得られた難燃性粘着シートを用いたこと以外は、実施例２０と同様にして粘着剤層をラミネートして難燃性粘着シートを得た。
【００９３】
（実施例２６）
実施例１で得られた難燃性粘着シートの代わりに、実施例１６で得られた難燃性粘着シートを用いたこと以外は、実施例２０と同様にして粘着剤層をラミネートして難燃性粘着シートを得た。
得られた難燃性粘着シートについて、実施例２０と同様にして難燃性、剪断強度及びＴ剥離強度を測定した。
【００９４】
（実施例２７）
実施例１で得られた難燃性粘着シートの代わりに、実施例１９で得られた難燃性粘着シートを用いたこと以外は、実施例２０と同様にして粘着剤層をラミネートして難燃性粘着シートを得た。
【００９５】
実施例２０〜２７で得られた難燃性粘着性テープについて、以下に示す如く、実施例１で行った試験法を一部変更して難燃性、剪断強度及びＴ剥離強度を測定した。測定結果は表２に示す。
【００９６】
＜剪断強度＞
図５に示すように、軟質塩化ビニル樹脂板６（ショアＤ硬度５０、幅２５ｍｍ×長さ１００ｍｍ×厚さ５ｍｍ）に、実施例４で得られた幅２０ｍｍ×長さ２０ｍｍの粘着性シートの粘着剤層５ａ側の面を貼付し、難燃性粘着シート２ａ側の面を、プライマー処理したポリカーボネート板３（幅２５ｍｍ×長さ１００ｍｍ×厚さ２ｍｍ）に貼り合わせて８０℃で１週間にわたって熱老化させて試験片を作成し、この試験片を用いて剪断強度を測定した。引張速度は、５０ｍｍ／分で行った。
【００９７】
（実施例２８）
冷却管、温度計及び攪拌器を備えたセパラブルフラスコに、２−エチルヘキシルアクリレート９００ｇ、アクリル酸１００ｇ、ｎ−ドデカンチオール０．２ｇ及び酢酸エチル９００ｇを仕込み、窒素ガス雰囲気下で、還流するまで昇温し、２０分間保持した後、ベンジルペルオキシド１ｇを酢酸エチル１００ｇに溶解した溶液を滴下し、４時間反応させた。その後、ベンジルペルオキシド１ｇを酢酸エチル１００ｇに溶解した溶液を滴下し、更に３時間反応させた。次いで、トルエン４００ｇを攪拌混合して、粘度１２０００ｃｐｓの粘着剤溶液（Ｂ）を得た。固形分は３６．４重量％であった。
【００９８】
この粘着剤溶液（Ｂ）１００ｇに、ヘキサメチレンジエチレンウレア（相互薬工社製、商品名）０．２ｇを加え、十分混合攪拌した後、脱泡し、離型処理したＰＥＴフィルム上に塗工し、厚み４０μｍの粘着剤層を形成した。その後、直ちに実施例７で得られた難燃性粘着シートの両面に粘着剤層をホットラミネートし、図８で示されるような難燃性粘着シートを得た。
【００９９】
（実施例２９）
２−エチルヘキシルアクリレート９５０ｇ、アクリル酸５０ｇ、ｎ−ドデカンチオール０．２ｇ及び酢酸エチル９００ｇを用いて実施例２８と同様の方法により粘度８９００ｃｐｓ、固形分３８重量％の粘着剤溶液（Ｃ）を得た。この粘着剤溶液（Ｃ）を用いて厚み４０μｍの粘着剤層を形成した。その後、この粘着剤層を実施例７で得られた難燃性粘着シートの両面にラミネートし、難燃性粘着シートを得た。
【０１００】
（比較例４）
実施例７で得られた難燃性粘着シートの代わりに、比較例１で得られた難燃性粘着シートを用いたこと以外は、実施例２８と同様にして難燃性粘着シートを得た。
【０１０１】
実施例２８〜２９及び比較例４で得られた難燃性粘着性テープについて、以下に示す如く、一部方法を変更して難燃性、剪断強度及びＴ剥離強度を測定した。
【０１０２】
＜剪断強度＞
図９に示すように、幅２０ｍｍ×長さ２０ｍｍの実施例９で得られた難燃性粘着性シートの両面に、ステンレス板７（幅５０ｍｍ×長さ１２５ｍｍ×厚み１ｍｍ）を貼り合わせて９０℃で２４時間にわたって熱老化させて試験片を作成し、この試験片を用いて剪断強度を測定した。引張速度は、５０ｍｍ／分で行った。
【０１０３】
＜Ｔ剥離強度＞
図１０に示すように、幅２０ｍｍ×長さ７０ｍｍの実施例９で得られた難燃性粘着シートの両面に、厚み３００μｍのアルミ箔４を貼り付け、９０℃で２４時間にわたって熱老化させて試験片を作成し、この試験片を用いてＴ剥離強度を測定した。引張速度は、２００ｍｍ／分で行った。
【０１０４】
（実施例３０）
セピオライト系繊維１００ｇの代わりに、平均粒子径が５μｍであり、且つ、屈折率が１．４９であるポリメチルメタクリレート架橋体微粒子（積水化成品工業社製、商品名「テクポリマーＭＢＸ−５」）１００ｇをフィラーとして用いたこと以外は、実施例１と同様にして部分光重合増粘組成物を得た。得られた部分光重合増粘組成物の転化率は４．９％、粘度は２９００ｃｐｓであった。以下の工程は実施例１と同様にして難燃性粘着シートを得た。得られた難燃性粘着シートの残存モノマーは０．１％未満であり、ゲル分率は８５％であった。
得られた難燃性粘着シートについて、実施例１と同様にして難燃性、剪断強度及びＴ剥離強度を測定した。更に、目視にて透明性を評価した。
【０１０５】
（実施例３１）
疎水化処理したガラス繊維１００ｇの代わりに、平均粒子径が５０μｍであり、且つ、屈折率が１．５０であるシリカ微粒子（洞海化学社製、商品名「Ｍ．Ｓ．ＧＥＬ Ｄ−５０−０Ａ」）１０００ｇをフィラーとして用いたこと以外は、実施例２と同様にして難燃性粘着シートを得た。
得られた難燃性粘着シートについて、実施例１と同様にして難燃性、剪断強度及びＴ剥離強度を測定した。更に、目視にて透明性を評価した。
【０１０６】
（実施例３２）
疎水化処理したガラス繊維１００ｇの代わりに、平均粒子径が２０μｍであり、且つ、屈折率が１．４８であるポリエチルアクリレート架橋体微粒子（積水化成品工業社製、商品名「テクポリマーＥＡＸ−１５」）２００ｇをフィラーとして用いたこと以外は、実施例３と同様にして難燃性光重合性組成物を得た。以下の工程は実施例３と同様にして難燃性粘着シートを得た。
得られた難燃性粘着シートについて、実施例１と同様にして難燃性、剪断強度及びＴ剥離強度を測定した。更に、目視にて透明性を評価した。
【０１０７】
（実施例３３）
実施例３１で得られた難燃性粘着シートの両方の表面をプライマー処理し、比較例１で得られた厚さ１００μｍの難燃性粘着シートを各々転写して表面粘着層を有する難燃性両面粘着シートを得た。得られた難燃性両面粘着シートをガラス板（幅２５ｍｍ×長さ１００ｍｍ）に貼り合わせて剪断強度を測定した。又、ガラス板を両面に貼り合わせて透明性を目視にて確認したところ、得られた難燃性両面粘着性シートは透明性があった。
【０１０８】
上記実施例３０〜３３で得られた難燃性粘着性テープについて、実施例１で行った難燃性、剪断強度及びＴ剥離強度の各試験に加えて、透明性の評価を目視試験で行い、透明で背後の物品が透視できるものに○、透視不能のものに×の２段階で評価し、表２に併せて示した。
【０１０９】
【表２】

【０１１０】
（実施例３４）
２−エチルヘキシルアクリレート４００ｇ、イソノニルアクリレート５００ｇＮ−ビニルピロリドン５０ｇ、脂環式エポキシアクリレート（ダイセルヒュルス社製、商品名「サイクロマーＡ−２００」）５０ｇ及び親水性シリカ（日本アエロジル社製、商品名「アエロジル２００」）４０ｇを、デイスパーで４時間にわたって１０００ｒｐｍで攪拌混合し、粘稠な液体を得た。これにポリエチレン微粒子（住友精化社製、商品名「フローセンＵＦ４」、平均粒子径：２５μｍ）２００ｇ及びイルガキュア１８４を０．３ｇを加え、均一になるまで攪拌混合した後、窒素ガスをパージし、溶存する酸素を除去した。以下の工程は実施例１と同様にして、厚さ約１ｍｍの難燃性粘着シートを得た。
【０１１１】
実施例２０で得られた粘着剤溶液（Ａ）１００ｇに不均化ロジンエステル（荒川化学社製、商品名「スーパーエステルＡ−１１５」）１０．０ｇ配合し、溶解した後、架橋剤としてコロネートＬ５５Ｅ（商品名）を１．５ｇ混合攪拌して粘着剤を調製し、離型処理したＰＥＴフィルム上に塗工し、乾燥して粘着剤層を作製し、直ちに、上記難燃性粘着シートの両面にホットラミネートして難燃性両面粘着テープを得た。得られた難燃性両面粘着テープについて、難燃性及び以下の方法により１８０°剥離強度を測定した。
【０１１２】
＜１８０°剥離強度＞
得られた難燃性両面粘着テープの片方の面に、コロナ放電処理を施したＰＥＴフィルム（厚み３８μｍ）をバッキングフィルムとして貼付し、片面粘着テープとした。被着体として、ポリプロピレン（ＰＰ）板（幅５０ｍｍ×長さ１２５ｍｍ×厚み１ｍｍ）に、ＪＩＳ Ｚ ０２３７の１８０°引きはがし法に準じて貼付し、１８０°剥離強度を測定した。
【０１１３】
（比較例５）
アクリロイロキシメチル（ジメチル）ホスフェート及びポリエチレン微粒子を用いなかったこと以外は、実施例３４と同様にして粘着テープを得た。
得られた粘着テープについて、実施例３４と同様の方法により難燃性及び１８０°剥離強度を測定した。
【０１１４】
上記実施例３４および比較例５の難燃性及び１８０°剥離強度の測定結果を以下の表３に示す。
【０１１５】
【表３】

【０１１６】
【発明の効果】
本発明の難燃性光重合性組成物は、叙上の如く構成されているので、高い難燃性が長期安定して保持され、且つ、剪断強度および剥離強度などの接着強度に優れた難燃性粘着テープを得ることができ、この難燃性粘着テープを用いることにより構造体などの接合作業を簡便に行うことができる。本発明によればまた、透明性に優れた難燃性粘着テープを得ることができる。
【図面の簡単な説明】
【図１】実施例１において、難燃性粘着シートを作製する際の、難燃性粘着シート及びＰＥＴフィルムの構成を示す断面図である。
【図２】実施例１で得られた難燃性粘着シートの剪断強度を測定する際に用いられる試験片の断面図である。
【図３】実施例１で得られた難燃性粘着シートのＴ剥離強度を測定する際に用いられる試験片の断面図である。
【図４】実施例４において、難燃性粘着シートを作製する際の、粘着シート、粘着剤層及びＰＥＴフィルムの構成を示す断面図である。
【図５】実施例４で得られた難燃性粘着シートの剪断強度を測定する際に用いられる試験片の断面図である。
【図６】比較例４において、剪断強度を測定する際に用いられる、試験片の断面図である。
【図７】比較例５において、剪断強度を測定する際に用いられる、試験片の断面図である。
【図８】実施例３５において、粘着性シートを得る際の、接着性シート、粘着剤層およびＰＥＴフィルムの構成を示す断面図である。
【図９】実施例３５において、剪断強度を測定する際に用いられる、試験片の断面図である。
【図１０】実施例３５において、Ｔ剥離強度を測定する際に用いられる、試験片の断面図である。
【符号の説明】
１，１’ ＰＥＴフィルム
２ａ，２ｂ，２ｃ 接着性シート
３ ポリカーボネート板
４ アルミ箔
５ａ，５ｂ 粘着剤層
６ 軟質塩化ビニル樹脂板
７ ステンレス板[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flame-retardant photopolymerizable composition and a flame-retardant pressure-sensitive adhesive tape using the same, and furthermore, it has excellent adhesive strength and can easily carry out joining work of a structure or the like. Related to adhesive tape.
Since the size of the flame-retardant pressure-sensitive adhesive tape of the present invention can be appropriately changed according to the purpose of use, the flame-retardant pressure-sensitive adhesive sheet includes a wide-width flame-retardant pressure-sensitive adhesive sheet.
[0002]
[Prior art]
Conventionally, a so-called double-sided foam adhesive tape having a polyethylene-based foam, a chloroprene-based foam, a urethane-based foam, an acrylic-based foam or the like as a base material and an acrylic-based adhesive layer provided on both surfaces thereof is solvent-free. In view of high work efficiency such as safety of work and quick development of adhesive strength, it is used for bonding work in many fields such as automobile industry, electric and electronic industry, building materials, etc. in place of adhesive. .
[0003]
Attempts have also been made to impart various functions such as flame retardancy while maintaining good adhesive properties of the adhesive tape. For example, Japanese Patent Application Laid-Open No. 8-53597 discloses a pressure-sensitive adhesive sheet comprising an acrylic resin matrix containing hollow particles, and by using hollow particles having a desired function, functionalization of a pressure-sensitive adhesive tape is achieved. There is a description to do.
[0004]
[Problems to be solved by the invention]
However, in the case of imparting flame retardancy, a sufficient flame retardant effect cannot be obtained only by including the flame retarded hollow particles. In addition, a method of simply adding a known flame retardant can be considered, but if a known halogen-based flame retardant is used, an environmental problem occurs at the time of incineration of waste after use, and if a non-halogen-based flame retardant is used, It is difficult to achieve compatibility with adhesive properties. That is, tricresyl phosphate, tris (β-chloroethyl) phosphate, tris (dichloropropyl) phosphate, tris (dibromopropyl) phosphate, and the like are frequently used as non-halogen flame retardants. It is too low in molecular weight compared to the synthetic resin or elastic polymer material that constitutes the adhesive tape base film or adhesive, and after addition molding, migration to the outside due to migration etc. is large, so flame retardancy is imparted Requires a relatively large amount of additive to perform, and not only adversely affects the performance of the added base film and pressure-sensitive adhesive, especially the adhesive performance, but also makes it extremely difficult to maintain stable long-term flame retardancy. The adhesive strength such as shear strength and peel strength is determined by the cohesive fracture strength of the foam base material. Will be even higher breaking strength, i.e., there is a problem that a high adhesive strength can not be obtained.
[0005]
An object of the present invention is to solve the above problems and to provide a pressure-sensitive adhesive tape having high flame retardancy, high shear strength and high peel strength, and a flame-retardant photopolymerizable composition used for forming these. It is in. Another object of the present invention is to provide a flame-retardant pressure-sensitive adhesive tape having excellent transparency.
[0006]
[Means for Solving the Problems]
The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, by using a compound having a phosphorus element in a molecule as a copolymer monomer component of the acrylic copolymer constituting the pressure-sensitive adhesive tape, an acrylic copolymer was obtained. Without lowering the excellent adhesive strength of the polymer composition, it was found that it exhibited stable flame retardancy for a long time, and furthermore, the specific photopolymerizable composition containing a specific filler, Was found to be improved, and the present invention was completed.
[Means for Solving the Problems]
[0007]
The invention according to claim 1 provides 50 to 98% by weight of at least one (meth) acrylic acid ester monomer (a) selected from (meth) acrylic acid esters having an alkyl group having 1 to 12 carbon atoms;
100 parts by weight of a monomer mixture having a polar group and containing 50 to 2% by weight of one or more monomers (b) selected from monomers copolymerizable with the (meth) acrylate monomer (a) Against
3 to 20 parts by weight of a compound (c) copolymerizable with the (meth) acrylic acid ester monomer (a) and the monomer (b) and having a phosphorus element in a molecule;
0.01-5 parts by weight of a photopolymerization initiator (d) and
The gist of the present invention is a flame-retardant photopolymerizable composition containing at least one filler selected from the group consisting of the following (e1) to (e9).
Fibrous filler (e1) having an average diameter of 0.2 to 20 μm and an average fiber length of 5 μm to 1 mm;
Porous fine particles (e2) having an average particle diameter of 0.5 to 150 μm;
Non-polar resin fine particles (e3) having an average particle diameter of 5 to 150 μm;
Organic fine particles (e4) having an average particle diameter of 5 to 100 µm and a glass transition temperature of 90 ° C or higher;
Flat fine particles (e5) having an average particle diameter of 1 to 50 μm and an aspect ratio of 20 to 40;
Fine particles (e6) having an average particle size of 1 to 150 μm and containing an aluminosilicate compound as a main component;
Silica-based fine particles (e7) having an average particle diameter of 10 to 150 μm and a smooth particle surface;
Silica-based fine particles (e8) having an average particle diameter of 10 to 150 μm and having a particle surface subjected to a hydrophobic treatment;
Fine particles (e9) having an average particle diameter of 5 to 150 μm and a refractive index of 1.47 to 1.51.
[0008]
As the (meth) acrylate monomer (a) used as a main component of the flame-retardant photopolymerizable composition, (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, preferably 4 carbon atoms (Meth) acrylic acid esters having an alkyl group of from 1 to 12, specifically, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) Acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate and the like can be mentioned. These can be used alone or in combination of two or more. From the balance between the tackiness and the cohesiveness of the flame-retardant photopolymerizable composition to be obtained, the homopolymer usually contains a (meth) acrylic acid ester having a glass transition temperature (Tg) of −50 ° C. or less as a main component. (Meth) acrylate having a lower alkyl group such as methyl (meth) acrylate and ethyl (meth) acrylate.
[0009]
The (meth) acrylic acid ester monomer (a) is contained in the monomer mixture in an amount of 50 to 98% by weight, preferably 70 to 90% by weight. When the content of the (meth) acrylate monomer (a) in the monomer mixture is less than 50% by weight, the resulting acrylic copolymer has too high a cohesive force, and the flame retardant obtained by using the same When the adhesive strength of the pressure-sensitive adhesive tape is insufficient and exceeds 98% by weight, the cohesive force of the obtained acrylic copolymer is too low, and the shear strength of the flame-retardant pressure-sensitive adhesive tape obtained by using the same is low. Will be insufficient.
[0010]
The monomer (b) has a polar group and is copolymerizable with the (meth) acrylate monomer (a). Examples of such a monomer (b) include carboxyl group-containing monomers such as (meth) acrylic acid, maleic acid, fumaric acid, and itaconic acid or anhydrides thereof; (meth) acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, Nitrogen-containing monomers such as acryloylmorpholine, (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and dimethylaminopropylacrylamide; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl methacrylate, A hydroxyl group-containing monomer such as hydroxybutyl acrylate is preferably used.
[0011]
The monomer (b) is contained in the monomer mixture at a ratio of 2 to 50% by weight, preferably 10 to 30% by weight. When the content of the monomer (b) in the monomer mixture is less than 2% by weight, the cohesive force of the obtained acrylic copolymer becomes too high, and the shear strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient. If it exceeds 50% by weight, the cohesive strength of the obtained acrylic copolymer will be too low, and the adhesive strength of the flame-retardant pressure-sensitive adhesive tape will be insufficient.
[0012]
The compound (c) having a phosphorus element in the molecule can be copolymerized with the (meth) acrylate monomer (a) and the monomer (b). The compound (c) is not particularly limited as long as it has a phosphorus element in the molecule and is copolymerizable with the (meth) acrylate monomer (a) and the monomer (b). However, for example, a compound represented by the following structural formula (I) or (II) is preferably used.
[0013]
Embedded image

[0014]
Specific examples of the above compound (c) include acryloyloxyphosphate, acryloyloxy (dimethyl) phosphate, acryloyloxy (diethyl) phosphate, acryloyloxy (diphenyl) phosphate, acryloyloxymethyl phosphate, acryloyloxymethyl (dimethyl) phosphate, acryloyl Roxymethyl (diethyl) phosphate, acryloyloxyethyl phosphate, acryloyloxyethyl (dimethyl) phosphate, acryloyloxyethyl (diethyl) phosphate, acryloyloxyhexyl phosphate, acryloyloxyoctyl phosphate, acryloyloxyphenyl phosphate, etc. No.
[0015]
According to a second aspect of the present invention, a compound which is copolymerizable with the (meth) acrylic acid ester monomer (a) and the monomer (b) according to the first aspect and has a phosphorus element in a molecule is represented by the above structural formula ( The gist is a flame-retardant photopolymerizable composition which is a compound represented by I) or (II).
[0016]
The compound (c) is contained in an amount of 3 to 20 parts by weight based on 100 parts by weight of the mixture of the (meth) acrylate monomer (a) and the monomer (b).
When the content is less than 3 parts by weight, the flame retardancy of the obtained acrylic copolymer does not satisfy the required performance, and the cohesive strength and creep resistance are not sufficiently given. On the other hand, if it exceeds 20 parts by weight, the cohesive force is too high, and the peel strength decreases.
[0017]
The photopolymerization initiator (d) is not particularly limited. For example, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone (trade name “Irgacure” manufactured by Ciba-Geigy) 2959 ") and the like; α-hydroxy-α, α'-dimethyl-acetophenone (manufactured by Ciba Geigy, trade name“ Darocur 1173 ”), methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone (manufactured by Ciba Geigy) Acetophenones such as 2-hydroxy-2-cyclohexyl acetophenone (trade name "Irgacure 184" manufactured by Ciba Geigy); ketals such as benzyl dimethyl ketal; and other halogenated ketones and acylphos. Finoxide, acylphosphonate, etc. Can be mentioned.
[0018]
The content of the photopolymerization initiator (d) is 0.01 to 5 parts by weight, preferably 0.05 part by weight, based on 100 parts by weight of the mixture of the (meth) acrylate monomer (a) and the monomer (b). ３3 parts by weight. When the content of the photopolymerization initiator (d) is less than 0.01 part by weight, the polymerization reaction is difficult to proceed, so that a sufficient conversion cannot be obtained. When the content exceeds 5 parts by weight, the radical generation amount is large. Too much, only a low molecular weight copolymer can be obtained.
[0019]
As described above, the filler used in the present invention includes fibrous filler (e1), porous fine particles (e2), nonpolar resin fine particles (e3), organic fine particles (e4), flat fine particles (e5), fine particles ( e6), silica-based fine particles (e7), silica-based fine particles (e8) and fine particles (e9).
[0020]
Examples of the fibrous filler (e1) include glass fiber, sepiolite fiber, chrysotile fiber, wollastonite, PMF (Processed Mineral Fiber), zonotolite, and potassium titanate. Asbestos-based fibers such as chrysotile should be avoided. In the flame-retardant photopolymerizable composition of the present invention, among the fibrous fillers, fillers having an average diameter of 0.2 to 20 μm and an average fiber length of 5 μm to 1 mm are used. When the average diameter of the fibrous filler is less than 0.2 μm, the obtained flame-retardant pressure-sensitive adhesive tape has insufficient shear strength, and when it exceeds 20 μm, a flame-retardant pressure-sensitive adhesive tape having a smooth surface cannot be obtained. When the average fiber length of the fibrous filler is less than 5 μm, the obtained flame-retardant pressure-sensitive adhesive tape has insufficient shear strength, and when it exceeds 1 mm, a flame-retardant pressure-sensitive adhesive tape having a smooth surface cannot be obtained.
[0021]
The content of the fibrous filler (e1) is preferably 0.5 to 20 parts by weight based on 100 parts by weight of the mixture of the (meth) acrylate monomer (a) and the monomer (b). Preferably it is 2 to 15 parts by weight. When the content of the fibrous filler (e1) is less than 0.5 part by weight based on 100 parts by weight of the monomer mixture, the obtained flame-retardant pressure-sensitive adhesive tape has insufficient shear strength, and when the content exceeds 20 parts by weight, The viscosity of the obtained flame-retardant photopolymerizable composition becomes extremely high, and a flame-retardant pressure-sensitive adhesive tape having a smooth surface cannot be obtained.
[0022]
Examples of the porous fine particles (e2) include natural inorganic fine particles such as diatomaceous earth, synthetic inorganic fine particles such as silica gel, and organic fine particles subjected to a porous treatment. In the flame-retardant photopolymerizable composition of the present invention, among the above-mentioned porous fine particles, fine particles having an average particle diameter of 0.5 to 150 μm are used. When the average particle diameter of the porous fine particles is less than 0.5 μm, the peel strength of the obtained flame-retardant pressure-sensitive adhesive tape is insufficient, and when it exceeds 150 μm, the shear strength of the flame-retardant pressure-sensitive adhesive tape is insufficient. Become.
[0023]
The content of the porous fine particles (e2) is preferably 0.5 to 20 parts by weight based on 100 parts by weight of the mixture of the (meth) acrylate monomer (a) and the monomer (b). Preferably it is 2 to 15 parts by weight. When the content of the porous fine particles (e2) is less than 0.5 part by weight with respect to 100 parts by weight of the monomer mixture, the adhesive strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient, and when the content exceeds 20 parts by weight, The viscosity of the obtained flame-retardant photopolymerizable composition becomes extremely high, and a flame-retardant pressure-sensitive adhesive tape having a smooth surface cannot be obtained.
[0024]
Examples of the non-polar resin fine particles (e3) include polyethylene fine particles such as low density polyethylene (LDPE), linear low density polyethylene (L-LDPE), and high density polyethylene (HDPE); polypropylene fine particles; silicone fine particles such as dimethyl silicone. And the like. In the flame-retardant photopolymerizable composition of the present invention, among the nonpolar resin fine particles, fine particles having an average particle diameter of 5 to 150 μm are used. When the average particle diameter of the nonpolar resin fine particles is less than 5 μm, the peel strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient, and when it exceeds 150 μm, the shear strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient. It becomes.
[0025]
The content of the nonpolar resin fine particles (e3) is preferably from 8 to 70 parts by weight, more preferably from 100 to 100 parts by weight of the mixture of the (meth) acrylate monomer (a) and the monomer (b). Is 10 to 60 parts by weight. When the content of the non-polar resin fine particles (e3) is less than 8 parts by weight based on 100 parts by weight of the monomer mixture, the adhesive strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient. The light transmittance of the resulting flame-retardant photopolymerizable composition is reduced, and the polymerization reaction rate is significantly reduced.
[0026]
Examples of the organic fine particles (e4) include polymethyl methacrylate, polystyrene, and the like, or a copolymer containing these as a main component, and the copolymer is preferably crosslinked. The organic fine particles may be a thermosetting resin such as a phenol resin and a guanamine resin. For the flame-retardant photopolymerizable composition of the present invention, among the organic fine particles, fine particles having an average particle diameter of 5 to 100 μm and a glass transition temperature of 90 ° C. or higher are used. When the average particle diameter of the organic fine particles is less than 5 μm, the peel strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient, and when it exceeds 100 μm, the shear strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient. When the glass transition temperature of the organic fine particles is less than 90 ° C., the adhesive strength of the obtained flame-retardant pressure-sensitive adhesive tape at a high temperature becomes insufficient.
[0027]
The content of the organic fine particles (e4) is preferably 5 to 50 parts by weight, more preferably 10 to 50 parts by weight, based on 100 parts by weight of the mixture of the (meth) acrylate monomer (a) and the monomer (b). ４０40 parts by weight. When the content of the organic fine particles (e4) is less than 5 parts by weight based on 100 parts by weight of the monomer mixture, the adhesive strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient, and when it exceeds 50 parts by weight, it is obtained. The viscosity of the flame-retardant photopolymerizable composition becomes extremely high, and a flame-retardant pressure-sensitive adhesive tape having a smooth surface cannot be obtained.
[0028]
Examples of the flat fine particles (e5) include synthetic mica such as fine powdered potassium / fluoric mica and fine powdered sodium / fluoric mica. It is an aluminum silicate compound such as maskovite and phlogopite, and a compound usually called mica can also be used.However, mica has a high degree of coloring and inhibits light transmission. In this case, it is not preferable. That is, in the present invention, it is preferable to use synthetic mica having high light transmittance. In the flame-retardant photopolymerizable composition of the present invention, among the flat fine particles, fine particles having an average particle diameter of 1 to 50 μm and an aspect ratio of 20 to 40 are used. When the average particle diameter of the flat fine particles is less than 1 μm, the peel strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient, and when it exceeds 50 μm, the shear strength of the flame-retardant pressure-sensitive adhesive tape becomes insufficient. When the aspect ratio of the flat fine particles is less than 20, the obtained flame-retardant pressure-sensitive adhesive tape has insufficient shear strength, and when it exceeds 40, a flame-retardant pressure-sensitive adhesive tape having a smooth surface cannot be obtained.
[0029]
The content of the flat fine particles (e5) is preferably 1 to 20 parts by weight, more preferably 100 parts by weight, based on 100 parts by weight of the mixture of the (meth) acrylate monomer (a) and the monomer (b). It is 3 to 15 parts by weight. When the content of the flat fine particles (e5) is less than 1 part by weight based on 100 parts by weight of the monomer mixture, the adhesive strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient. The viscosity of the resulting flame-retardant photopolymerizable composition becomes extremely high, and a flame-retardant pressure-sensitive adhesive tape having a smooth surface cannot be obtained.
[0030]
Examples of the fine particles (e6) containing the aluminosilicate compound as a main component include those synthesized from alumina and silicate, and fly ash discharged from a power plant or the like. The fine particles (e6) may be hollow fine particles, and examples of such hollow fine particles include a shirasu balloon and a flushiah balloon. Shirasu balloons are made by baking and foaming Shirasu soil (volcanic ash) that exists in large quantities in Kyushu. Commercial products include Winlite (trade name) manufactured by Ichiji Kasei Co., Ltd., and Super Balloon (manufactured by Showa Chemical Industry Co., Ltd.) Product name). Fly ash balloons are light ash mainly discharged from power plants. Commercially available products include Philite (trade name) manufactured by Philite, UK, Microcells (trade name) manufactured by Onoda Cement Co., and PQ Corporation. Extended sphere (product name) and the like.
[0031]
In the flame-retardant photopolymerizable composition of the present invention, among the fine particles (e6), fine particles having an average particle diameter of 1 to 150 µm are used. When the average particle diameter of the fine particles (e6) is less than 1 μm, the peel strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient, and when it exceeds 150 μm, the shear strength of the flame-retardant pressure-sensitive adhesive tape becomes insufficient.
[0032]
The content of the fine particles (e6) is preferably 1 to 40 parts by weight, more preferably 3 to 40 parts by weight, based on 100 parts by weight of the mixture of the (meth) acrylate monomer (a) and the monomer (b). 30 parts by weight. When the content of the fine particles (e6) is less than 1 part by weight with respect to 100 parts by weight of the monomer mixture, the adhesive strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient. The light transmittance of the flammable photopolymerizable composition is reduced, and the polymerization reaction is significantly slowed down.
[0033]
Examples of the silica-based fine particles (e7) include SiO2 such as alkali glass and borosilicate glass. ₂ Containing about 50 to about 70% by weight of ₂ Containing at least 98% by weight of Al; ₂ O ₃ And SiO ₂ Fine particles using aluminosilicates or the like as a main component and fine particles obtained by subjecting the surface of these fine particles to a hydrophobic treatment. In the flame-retardant photopolymerizable composition of the present invention, among the fine particles, fine particles having an average particle diameter of 10 to 150 μm and a smooth surface are used. When the particle size is less than 10 μm, the peel strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient, and when it exceeds 150 μm, the shear strength of the flame-retardant pressure-sensitive adhesive tape becomes insufficient. In addition, since the surface of the silica-based fine particles is smooth, the contact area between the silica-based fine particles and the monomer mixture contained in the flame-retardant photopolymerizable composition is reduced, and the flame-retardant photopolymerizable composition is Hardly increases viscosity. Therefore, it is possible to easily apply the flame-retardant photopolymerizable composition when producing the flame-retardant pressure-sensitive adhesive tape.
[0034]
The content of the silica-based fine particles (e7) is preferably 50 to 175 parts by weight, more preferably 100 parts by weight of the mixture of the (meth) acrylate monomer (a) and the monomer (b). 70 to 150 parts by weight. When the content of the silica-based fine particles (e7) is less than 50 parts by weight, the peel strength of the obtained flame-retardant pressure-sensitive adhesive tape is insufficient, and when it exceeds 175 parts by weight, the shear strength of the flame-retardant pressure-sensitive adhesive tape is low. Will be insufficient.
[0035]
Examples of the silica-based fine particles (e8) whose particle surfaces have been hydrophobized include glasses such as alkali glass and borosilicate glass; ₂ , Silica gel, etc. containing 98% by weight or more; glass balloons; shirasu balloons, etc. In order to perform the hydrophobic treatment, it is preferable to use a silane coupling agent such as polydimethylsiloxane, trimethoxyoctylsilane, hexamethylsilazane, and trimethoxystearylsilane. Since the surface of the fine particles is subjected to the hydrophobic treatment, the interfacial adhesion between the fine particles (e8) and the acrylic copolymer surrounding the fine particles is improved, and thus the flame retardant photopolymerizable composition is used. The resulting flame-retardant pressure-sensitive adhesive tape has excellent adhesive strength.
[0036]
In the flame-retardant photopolymerizable composition of the present invention, among the fine particles, fine particles having an average particle diameter of 10 to 150 µm are used. When the particle size is less than 10 μm, the resulting flame-retardant pressure-sensitive adhesive tape has insufficient peel strength, and when it exceeds 150 μm, the flame-retardant pressure-sensitive adhesive tape has insufficient shear strength.
[0037]
The silica-based fine particles (e8) are preferably contained so as to account for 15 to 50% by volume of the total volume of the obtained flame-retardant photopolymerizable composition. When the content of the silica-based fine particles (e8) is less than 10% by volume in the total volume of the obtained flame-retardant photopolymerizable composition, the peel strength of the obtained flame-retardant pressure-sensitive adhesive tape is insufficient. When the ratio exceeds 50% by volume, the shear strength of the flame-retardant pressure-sensitive adhesive tape becomes insufficient. Among the fine particles (e8), the specific gravity of the fine particles having no hollow structure is about 2.1. When hollow fine particles are used as the fine particles (e8), fine particles having a specific gravity of 0.15 to 1.1 are preferably used. Therefore, when the content of the silica-based fine particles (e8) is converted into parts by weight, the content is 2 to 175 parts by weight based on 100 parts by weight of the mixture of the (meth) acrylate monomer (a) and the monomer (b). Preferably, it is more preferably 3 to 150 parts by weight.
[0038]
Examples of the fine particles (e9) include organic fine particles such as polymethyl methacrylate, polyethyl acrylate, polybutyl methacrylate, and urethane elastomer; and silica fine particles. When organic fine particles are used, the polymer constituting the organic fine particles is preferably crosslinked in order to improve heat resistance. In the flame-retardant photopolymerizable composition of the present invention, among the fine particles, fine particles having an average particle diameter of 5 to 150 μm and a refractive index of 1.47 to 1.51 are used. When the average particle diameter of the fine particles is less than 5 μm, the peel strength of the obtained flame-retardant pressure-sensitive adhesive tape becomes insufficient, and when it exceeds 150 μm, the shear strength of the flame-retardant pressure-sensitive adhesive tape becomes insufficient. When the refractive index of the fine particles is out of the range of 1.47 to 1.51, the transparency of the flame-retardant pressure-sensitive adhesive tape obtained using the flame-retardant photopolymerizable composition containing the fine particles (e9) is not good. Will be enough. It is not preferable that the fine particles (e9) are hollow fine particles. This is because even if the refractive index of the shell of the hollow fine particles is in the range of 1.47 to 1.51, the light is reflected at the interface between the shell and the inside, and the transparency is lost.
[0039]
The fine particles (e9) are preferably contained so as to account for 15 to 50% by volume of the total volume of the obtained flame-retardant photopolymerizable composition, and more preferably 20 to 40% by volume. It is contained so as to account for the ratio. When the content of the fine particles (e9) is less than 15% by volume in the total volume of the obtained flame-retardant photopolymerizable composition, the adhesive strength of the resulting flame-retardant pressure-sensitive adhesive tape becomes insufficient, If the proportion exceeds 50% by volume, the transparency of the flame-retardant pressure-sensitive adhesive tape becomes insufficient.
[0040]
The flame-retardant photopolymerizable composition of the present invention comprises the (meth) acrylate monomer (a), the monomer (b), a compound having a phosphorus element in a molecule (c), a photopolymerization initiator (d), And any one of the fillers (e1) to (e9) can be obtained by mixing with uniform stirring according to a conventional method.
[0041]
The flame-retardant photopolymerizable composition of the present invention may optionally contain a monomer having a Tg of 0 ° C. or more, such as vinyl acetate, vinyl propionate, or isobornyl (meth) acrylate, in order to improve heat resistance. May be. The flame-retardant photopolymerizable composition of the present invention may also contain a tackifier resin (TF). Suitable TFs include rosin-based resins, modified rosin-based resins, terpene-based resins, terpene-phenol-based resins, C5 and C9-based petroleum resins, cumarone resins, and the like, and hydrogenated products thereof. Two or more can be used in combination. However, when the monomer having a Tg of 0 ° C. or more and / or the TF is blended with the flame-retardant photopolymerizable composition and polymerized, the polymerization rate may be reduced or the molecular weight may be reduced. In such a case, it is preferable to appropriately adjust the amounts of the chain transfer agent and the compound (c) having a phosphorus element in the molecule.
[0042]
The chain transfer agent is used to adjust the molecular weight of the copolymer, and examples thereof include n-dodecyl mercaptan and t-dodecyl mercaptan. These chain transfer agents can be used in an amount of 0.01 to 0.1 part by weight based on 100 parts by weight of the mixture of the (meth) acrylate monomer (a) and the monomer (b).
[0043]
In order to produce the flame-retardant pressure-sensitive adhesive tape of the present invention, first, the flame-retardant photopolymerization is carried out so that the filler is uniformly dispersed so that the surface of the obtained flame-retardant pressure-sensitive adhesive tape is smooth. The composition is sufficiently stirred and thickened to give thixotropic properties. This flame-retardant photopolymerizable composition is applied to a release-treated paper or polyethylene terephthalate (PET) film so as to have a predetermined thickness, and then the coated surface is irradiated with light to obtain a flame-retardant adhesive. You can get tape.
[0044]
The flame-retardant pressure-sensitive adhesive tape can be formed to have a thickness in the range of 50 μm to 5 mm. When a pressure-sensitive adhesive tape having a thickness of 100 μm or less is manufactured, the adhesive tape is applied using a flame-retardant photopolymerizable composition having a viscosity of about 1000 cps and a thixotropic index (TI) value of about 1.5 showing thixotropic properties. However, when producing a pressure-sensitive adhesive tape having a thickness exceeding 100 μm, it is preferable to further increase the viscosity of the flame-retardant photopolymerizable composition.
[0045]
Means for increasing the viscosity of the flame-retardant photopolymerizable composition include elastomers such as diblock or triblock rubber such as acrylic rubber, nitrile rubber, styrene-isoprene-styrene block (SIS); polymethyl methacrylate (PMMA) Alternatively, a thermoplastic plastic such as polystyrene (PSt) or the like may be dissolved, or silica particles or alumina particles having an average particle diameter of 5 μm or less may be mixed with the flame-retardant photopolymerizable composition. In the case of adding an inorganic substance among the above additives, it is preferable to use particles whose surface has been subjected to a hydrophobizing treatment from the viewpoint that they can be dispersed up to the primary particles more quickly. As another method for increasing the viscosity, there is a method in which a part of the flame-retardant photopolymerizable composition is partially polymerized in advance without adding the above-mentioned additives. This partial polymerization should be performed before adding the compound (c) having a phosphorus element in the molecule to prevent microgel formation. If the microgel is partially formed, it causes generation of streaks or the like during coating. The monomers to be partially polymerized should be between 1.5% and 60% by weight of the total monomers. When the amount of the monomer to be partially polymerized is less than 1.5% by weight, the required viscosity cannot be obtained. When the amount exceeds 60% by weight, the viscosity of the obtained flame-retardant photopolymerizable composition becomes too high. Can not work.
[0046]
Irradiation of light to the flame-retardant photopolymerizable composition applied on the substrate as described above is performed under the following conditions.
[0047]
Lamps having a light emission distribution at a light wavelength of 400 nm or less are used for light irradiation. Examples of such lamps include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, and a metal halide lamp. Among them, the chemical lamp efficiently emits light in the active wavelength region of the initiator, and since the composition other than the initiator does not absorb much light in this wavelength region, it reaches the inside of the flame-retardant photopolymerizable composition. Light is transmitted therethrough, which is preferable for producing a sheet having a large thickness. The light irradiation intensity of the lamp is a factor that affects the degree of polymerization of the obtained polymer, and is appropriately controlled for each performance of the target product. For example, when a commonly used cleavage-type initiator having an acetophenone group is blended, a wavelength region effective for photodecomposition of the initiator (different depending on the initiator, but light of 365 nm to 420 nm is usually used) The light irradiation intensity is 0.1 to 100 mW / cm. ² Is preferably within the range.
[0048]
The photopolymerization in the present invention is inhibited by oxygen in the air and oxygen dissolved in the flame-retardant photopolymerizable composition. For this reason, light irradiation must be carried out using a method that does not inhibit oxygen. As such a technique, the coated flame-retardant photopolymerizable composition is covered with a film such as polyethylene terephthalate (PET) or Teflon whose surface has been release-treated, and the flame-retardant light- There is a method of irradiating the polymerizable composition with light. Alternatively, there is a method in which a reaction is performed by irradiating light from the outside through a light-transmitting window in an inert zone in which oxygen is replaced with an inert gas such as nitrogen gas or carbon dioxide gas. In the method of reacting in the inert zone, in order to make the polymerization conversion of the flame-retardant photopolymerizable composition 99.7% or more, the oxygen concentration in the irradiation atmosphere is preferably 5000 ppm or less, More preferably, it is 300 ppm or less.
[0049]
When the photopolymerization reaction proceeds rapidly, the heat of polymerization causes the release treatment film to be coated or the release treatment film for the cover to expand and contract by heating, resulting in streaks and the like on the resulting flame-retardant adhesive tape. There are cases. The generation of such streaks can be prevented by suppressing radiant heat from the lamp using a light cut filter or by cooling the rear surface opposite to the irradiation surface by contact with a cooling plate.
[0050]
The flame-retardant pressure-sensitive adhesive tape of the present invention is obtained by curing the flame-retardant photopolymerizable composition of the present invention by photopolymerization as described above. When the glass transition temperature (Tg) of the crosslinked product obtained by the photopolymerization is 50 ° C. or less, the flame-retardant pressure-sensitive adhesive tape composed of the crosslinked product is bonded only by slightly heating with a drier or the like during the joining operation. It becomes a heat-sensitive type flame-retardant adhesive tape that expresses force. When the Tg of the crosslinked product obtained by photopolymerization is 20 ° C. or lower, a flame-retardant pressure-sensitive adhesive tape that is tacky at room temperature is obtained. When the on-site workability in winter where the ambient temperature is 0 ° C. or less is emphasized, Tg should be set to 5 ° C. or less. The adhesive strength of the flame-retardant pressure-sensitive adhesive tape can be improved by adding a filler as in the present invention, irrespective of the Tg of the crosslinked product obtained by polymerization.
[0051]
The flame-retardant pressure-sensitive adhesive tape of the present invention can be prepared by further laminating a pressure-sensitive adhesive layer on one or both surfaces of the self-viscous flame-retardant pressure-sensitive adhesive tape. As the pressure-sensitive adhesive constituting the newly laminated pressure-sensitive adhesive layer, an acrylic, rubber-based, silicone-based pressure-sensitive adhesive can be used, and these pressure-sensitive adhesives are solvent-type, water-dispersion-type, and hot-melt-type. Any type may be used. Lamination may be performed by applying a photopolymerizable composition to the surface and irradiating with light (hereinafter, referred to as a photopolymerizable type). When the pressure-sensitive adhesive to be used is a hot-melt type or a photopolymerization type, it can be directly applied and laminated on the above-mentioned flame-retardant pressure-sensitive adhesive tape as a substrate. When the pressure-sensitive adhesive to be used is a solvent-type or water-dispersion-type, the pressure-sensitive adhesive is coated on a release-treated film, dried to form a pressure-sensitive adhesive layer, and then the base material is formed. A method of transferring and laminating the pressure-sensitive adhesive layer on a flame-retardant pressure-sensitive adhesive tape is used. When a solvent-type or water-dispersed pressure-sensitive adhesive is applied directly on the flame-retardant pressure-sensitive adhesive tape as a base material, a solvent or moisture diffuses into the flame-retardant pressure-sensitive adhesive tape, and it takes a long time to dry it. It may take time.
[0052]
The composition and composition of the pressure-sensitive adhesive should be changed according to the adherend. For example, when the adherend is a polyolefin-based material such as polyethylene or polypropylene, it is preferable to use an acrylic-based pressure-sensitive adhesive or a natural rubber-based pressure-sensitive adhesive containing 20 to 35% by weight of a tackifier resin. When the adherend is a soft vinyl chloride resin, an acrylic pressure-sensitive adhesive containing N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, or the like as a polar component and not containing a carboxyl group such as (meth) acrylic acid When the composition is used, an adhesive tape having excellent heat resistance can be obtained.
[0053]
By blending various fillers with the flame-retardant photopolymerizable composition used for producing the flame-retardant pressure-sensitive adhesive tape, the physical properties of the obtained flame-retardant pressure-sensitive adhesive tape are improved. For example, difficult to obtain by blending fibrous filler (e1), non-polar resin fine particles (e3), organic fine particles (e4), flat fine particles (e5), silica-based fine particles (e7) and fine particles (e9). The adhesive strength of the flammable adhesive tape is improved. Although the reason why the adhesive strength is improved is not necessarily clear, it is presumed that the elastic modulus is increased and the shear strength is improved by blending specific fine particles into the acrylic crosslinked product having the specific composition.
[0054]
The flame-retardant photopolymerizable composition of the present invention is constituted as described above. In particular, the compound (c) having a phosphorus element in the molecule is a (meth) acrylate monomer (a) and a monomer (b) To form a main component acrylic copolymer, so that a high amount of flame retardancy can be stably maintained for a long period of time by copolymerization of a small amount of a compound (c) having a phosphorus element in a molecule. The flame-retardant pressure-sensitive adhesive tapes according to claims 3 and 4, which are retained and obtained by using these, exhibit high flame-retardancy and are difficult to be used in the production of the flame-retardant pressure-sensitive adhesive tapes. Fibrous filler (e1); fine particles having a porous surface (for example, porous particles (e2)); fine particles having a polar group such as a silanol group on the surface (for example, an aluminosilicate compound) (E) )); Alternatively, in the case where fine particles whose surface is subjected to a hydrophobic treatment (for example, silica-based fine particles (e8)) are blended as a filler, the surface area per volume of the filler is relatively large, and the bonding area increases. It is considered that a flame-retardant pressure-sensitive adhesive tape having excellent adhesive strength can be obtained with a smaller amount of filler.
[0055]
A flame-retardant pressure-sensitive adhesive tape produced by using a flame-retardant photopolymerizable composition containing fine particles (e9) as a base material, and an acrylic pressure-sensitive adhesive layer laminated thereon to produce a flame-retardant pressure-sensitive adhesive tape In this case, since the refractive index of the fine particles (e9) (in the range of 1.47 to 1.51) is close to the refractive index of the acrylic pressure-sensitive adhesive, the obtained flame-retardant pressure-sensitive adhesive tape has excellent transparency.
[0056]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to Examples.
[0057]
(Example 1)
In a separable flask equipped with a cooling tube, a thermometer and a stirrer, 900 g of 2-ethylhexyl acrylate, 100 g of acrylic acid, 0.3 g of Irgacure 184 (trade name, manufactured by Ciba Geigy), and sepiolite-based fiber (manufactured by Mizusawa Chemical Industry Co., Ltd.) 100 g of trade name “Aid Plus SP”, average diameter: 0.2 μm, average fiber length: 7.5 μm) was charged, and the mixture was stirred and mixed until uniformly dispersed, and then dissolved oxygen was removed by nitrogen gas purge. Next, when the composition was irradiated with ultraviolet light using a black light lamp, the viscosity of the composition increased at the same time as the temperature of the composition increased. When the temperature of the composition increased by 5 ° C., the light irradiation was stopped (this composition is referred to as a partially photopolymerized thickening composition). The resulting partially photopolymerized thickening composition had a conversion of 4.1% and a viscosity of 2300 cps.
[0058]
Further, 180 g of acryloyloxyphosphate (trade name “Light Ester PA” manufactured by Kyoei Chemical Co., Ltd.) was blended with the partially photopolymerized thickening composition, and as shown in FIG. 1, a release-treated polyethylene terephthalate having a thickness of 38 μm. This composition is coated on a film (PET film) 1 so that the thickness at the end of polymerization is 1.0 ± 0.1 mm, and the same PET film 1 ′ is used, and the release treated surface is The coated surface was covered so as to be in contact with the coated surface.
[0059]
Then, using a chemical lamp, the irradiation intensity on the PET film 1 'used for this cover was 2 mW / cm. ² The height of the lamp was adjusted so that the pressure was adjusted, and irradiation was performed for 8 minutes to obtain a flame-retardant pressure-sensitive adhesive sheet 2a. The residual monomer of the obtained flame-retardant pressure-sensitive adhesive sheet 2a was 0.1%, and the gel fraction was 86%.
[0060]
(Example 2)
950 g of isononyl acrylate, 10 g of acrylic acid, 40 g of N-vinylpyrrolidone and 40 g of hydrophilic silica (trade name "Aerosil 200" manufactured by Nippon Aerosil Co., Ltd.) were stirred and mixed at 1000 rpm for 4 hours with a disper to obtain a viscous liquid. Was. To this, 0.3 g of "Irgacure 184" and 120 g of "Light Ester PA" were added, and the mixture was stirred and mixed until the mixture became uniform. Thereafter, nitrogen gas was purged to remove dissolved oxygen. The following steps were performed in the same manner as in Example 1 to obtain a flame-retardant pressure-sensitive adhesive sheet having a thickness of 1 mm.
[0061]
(Example 3)
700 g of 2-ethylhexyl acrylate, 200 g of isooctyl acrylate, 100 g of acrylic acid, and 70 g of hydrophobic silica (trade name "Aerosil R976" manufactured by Nippon Aerosil Co., Ltd.) are stirred and mixed at 1000 rpm for 30 minutes with a disper to obtain a viscous liquid. Was. 100 g of glass fiber (used as a filler) having a hydrophobized surface (made by Asahi Fiberglass Co., Ltd., trade name "Milled Fiber T10", average diameter: 13 μm, average fiber length: 200 μm), 80 g of “Light Ester PA” Then, 0.3 g of "Irgacure 651" (trade name, manufactured by Ciba Geigy) was added, and the mixture was stirred and mixed until the mixture became uniform. Then, nitrogen gas was purged to remove dissolved oxygen. The following steps were performed in the same manner as in Example 1 to obtain a flame-retardant pressure-sensitive adhesive sheet having a thickness of about 1 mm.
[0062]
(Example 4)
A portion was prepared in the same manner as in Example 1, except that 100 g of porous silica gel having an average particle diameter of 75 μm (trade name “Silbead D-MS1000”, manufactured by Mizusawa Chemical Industry Co., Ltd.) was used instead of 100 g of sepiolite fiber. A photopolymerized thickening composition was obtained. The resulting partially photopolymerized thickening composition had a conversion of 4.1% and a viscosity of 2300 cps. The following steps were performed in the same manner as in Example 1 to obtain a flame-retardant pressure-sensitive adhesive sheet. The residual monomer of the obtained flame-retardant pressure-sensitive adhesive sheet was less than 0.1%, and the gel fraction was 85%.
[0063]
(Example 5)
Example 1 was repeated except that 50 g of hollow porous silica fine particles (manufactured by Suzuki Yushi Kogyo Co., Ltd., trade name “Godball B-25C”) having an average particle diameter of 25 μm were used as a filler instead of 100 g of the glass fiber subjected to the hydrophobic treatment. In the same manner as in Example 3, a flame-retardant photopolymerizable composition was obtained. The following steps were performed in the same manner as in Example 3 to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0064]
(Example 6)
Except that 100 g of precipitated silica having an average particle diameter of 0.7 μm (trade name “Mizukasil P-527U”, manufactured by Mizusawa Chemical Industry Co., Ltd.) was used as a filler instead of 100 g of the glass fiber subjected to the hydrophobic treatment. In the same manner as in Example 3, a flame-retardant photopolymerizable composition was obtained. The following steps were performed in the same manner as in Example 3 to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0065]
(Example 7)
A portion was prepared in the same manner as in Example 1 except that 600 g of low-density polyethylene fine particles (trade name “Flosen UF4”, manufactured by Sumitomo Seika Co., Ltd., average particle diameter: 25 μm) were used as fillers instead of 100 g of sepiolite fibers. A photopolymerized thickening composition was obtained. The resulting partially photopolymerized thickening composition had a conversion of 4.1% and a viscosity of 2300 cps. The following steps were performed in the same manner as in Example 1 to obtain a flame-retardant pressure-sensitive adhesive sheet. The residual monomer in the obtained flame-retardant pressure-sensitive adhesive sheet was 0.1%, and the gel fraction was 80%.
[0066]
(Example 8)
Example 1 was repeated except that 200 g of silicone fine particles (trade name “Trefil E-600”, manufactured by Dow Corning Toray Silicone Co., average particle size: 5 μm) was used as a filler instead of 100 g of the glass fiber subjected to the hydrophobic treatment. In the same manner as in Example 3, a flame-retardant photopolymerizable composition was obtained. The following steps were performed in the same manner as in Example 3 to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0067]
(Example 9)
Example 3 except that 500 g of high-density polyethylene fine particles (trade name “Miperon XM-220”, manufactured by Mitsui Petrochemical Co., average particle size: 20 μm) was used as a filler instead of 100 g of the glass fiber subjected to the hydrophobic treatment. A flame-retardant photopolymerizable composition was obtained in the same manner as described above. The following steps were performed in the same manner as in Example 3 to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0068]
(Example 10)
Instead of using 100 g of sepiolite-based fiber, 500 g of crosslinked polymethyl methacrylate (PMMA) fine particles (manufactured by Sekisui Chemical Co., Ltd., trade name “Techpolymer MBX-40”) having an average particle diameter of 40 μm was used as a filler, A partially photopolymerized thickening composition was obtained in the same manner as in Example 1. The conversion of the obtained composition was 4.8%, and the viscosity was 2500 cps. The following steps were performed in the same manner as in Example 1 to obtain a flame-retardant pressure-sensitive adhesive sheet. The residual monomer of the obtained flame-retardant pressure-sensitive adhesive sheet was less than 0.1%, and the gel fraction was 85%.
[0069]
(Example 11)
In the same manner as in Example 2 except that 200 g of crosslinked polystyrene fine particles having an average particle diameter of 20 μm (manufactured by Sekisui Chemical Co., Ltd., trade name “Techpolymer SBX-20”) was used as a filler instead of 100 g of glass fiber, Thus, a photopolymerizable composition was obtained. The following steps were performed in the same manner as in Example 2 to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0070]
(Example 12)
Same as Example 1 except that 50 g of mica having an average particle diameter of 3 μm (manufactured by Corp Chemical Co., trade name “Synthetic Mica MK-100”, aspect ratio: 30) was used as a filler instead of 100 g of sepiolite fiber. Thus, a partially photopolymerized thickening composition was obtained. The following steps were performed in the same manner as in Example 1 to obtain a flame-retardant pressure-sensitive adhesive sheet. The residual monomer of the obtained flame-retardant pressure-sensitive adhesive sheet was less than 0.1%, and the gel fraction was 83%.
[0071]
(Example 13)
Instead of 100 g of sepiolite-based fiber, the average particle diameter is 45 μm and SiO ₂ About 60% by weight and Al ₂ O ₃ A partially photopolymerized thickening composition was obtained in the same manner as in Example 1, except that 300 g of fly ash balloon (trade name “Microcells SL75” manufactured by Onoda Cement Co.) containing about 38% by weight was used as a filler. Was. The resulting partially photopolymerized thickening composition had a conversion of 4.1% and a viscosity of 2300 cps. The following steps were performed in the same manner as in Example 1 to obtain a flame-retardant pressure-sensitive adhesive sheet. The residual monomer of the obtained flame-retardant pressure-sensitive adhesive sheet was less than 0.1%, and the gel fraction was 85%.
[0072]
(Example 14)
Instead of 100 g of glass fiber, the average particle diameter is 40 μm and SiO ₂ About 75% by weight and Al ₂ O ₃ A flame-retardant photopolymerizable composition was prepared in the same manner as in Example 2 except that 200 g of a Shirasu balloon (trade name “Winlite SC-50” manufactured by Ichi Kasei Corporation) containing about 15% by weight was used as a filler. Got. The following steps were performed in the same manner as in Example 2 to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0073]
(Example 15)
Instead of 100 g of the hydrophobized glass fiber, the average particle diameter is 2.4 μm, and SiO 2 ₂ About 48% by weight and Al ₂ O ₃ A photopolymerizable composition was obtained in the same manner as in Example 3, except that 100 g of aluminosilicate-based fine particles (manufactured by Mizusawa Chemical Industry Co., Ltd., trade name: "Silton AMT25") containing about 40% by weight were used as a filler. . The following steps were performed in the same manner as in Example 3 to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0074]
(Example 16)
Partial photopolymerization thickening was performed in the same manner as in Example 1 except that 1000 g of glass beads (trade name “EGB731”, manufactured by Toshiba Barotini Co., average particle size: 25 μm) was used as a filler instead of 100 g of sepiolite-based fiber. A composition was obtained. The following steps were performed in the same manner as in Example 1 to obtain a flame-retardant pressure-sensitive adhesive sheet. The residual monomer of the obtained flame-retardant pressure-sensitive adhesive sheet was 0.1%, and the gel fraction was 84%.
[0075]
(Example 17)
Example 2 except that 1000 g of silica beads (trade name “MS GEL D-50-0A”, average particle size: 50 μm, manufactured by Dokai Chemical Co., Ltd.) was used as a filler instead of 100 g of glass fiber. A flame-retardant photopolymerizable composition was obtained in the same manner as described above. The following steps were performed in the same manner as in Example 2 to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0076]
(Example 18)
Example 3 except that instead of 100 g of the glass fiber subjected to the hydrophobic treatment, 1000 g of glass beads (trade name: “EGB731N”, average particle size: 20 μm, manufactured by Toshiba Barotini Co., Ltd., average particle size: 20 μm) were used as the filler. A flame-retardant photopolymerizable composition was obtained in the same manner as described above. The following steps were performed in the same manner as in Example 3 to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0077]
(Example 19)
Instead of 100 g of the glass fiber subjected to the hydrophobic treatment, 50 g of hollow glass fine particles having an average particle diameter of 60 μm (manufactured by Asahi Glass Co., Ltd., trade name “Celstar Z-27”, specific gravity 0.27) were treated with 50 g of polydimethylsiloxane. Except having used as a filler, it carried out similarly to Example 3, and obtained the flame-retardant photopolymerizable composition. The following steps were performed in the same manner as in Example 3 to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0078]
(Comparative Example 1)
A flame-retardant photopolymerizable composition was obtained in the same manner as in Example 1 except that no fibrous filler was contained. The conversion of the obtained flame-retardant photopolymerizable composition was 5.1%, and the viscosity was 4100 cps. Using this flame-retardant photopolymerizable composition, a flame-retardant pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1.
[0079]
(Comparative Example 2)
A photopolymerizable composition was obtained in the same manner as in Example 1 except that “light ester PA” was not contained. The conversion of the composition thus obtained was 4.1% and the viscosity was 2300 cps. Using this composition, an adhesive sheet was obtained in the same manner as in Example 1.
[0080]
The flame retardancy, shear strength and T peel strength of the flame retardant pressure-sensitive adhesive tapes obtained in Examples 1 to 19 and Comparative Examples 1 and 2 were measured by the following methods. Table 1 shows the measurement results.
[0081]
<Shear strength>
As shown in FIG. 2, the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet 2a having a width of 20 mm × length 20 mm is bonded to a polycarbonate plate 3 (width 25 mm × length 10 mm × thickness 2 mm) which has been subjected to primer surface treatment. A test piece was prepared by allowing the test piece to stand, and the shear strength was measured using the test piece. The tensile speed was 50 mm / min.
[0082]
<T peel strength>
As shown in FIG. 3, a 300 μm thick aluminum foil 4 having a primer surface treatment was attached to both surfaces of the pressure-sensitive adhesive sheet 2 a having a width of 20 mm × a length of 70 mm, and left at room temperature for 24 hours to prepare a test piece. T peel strength was measured using the test piece. The tensile speed was 200 mm / min.
[0083]
<Flame retardant>
The evaluation of flame retardancy was performed based on flammability classification in accordance with JIS D1201.
[0084]
[Table 1]

[0085]
(Example 20)
In a separable flask equipped with a condenser, a thermometer and a stirrer, 200 g of 2-ethylhexyl acrylate, 700 g of n-butyl acrylate, 100 g of N-vinylpyrrolidone, 2 g of 2-hydroxyethyl methacrylate, 2 g of n-dodecanethiol and 900 g of ethyl acetate Was heated under reflux in a nitrogen gas atmosphere until the temperature was refluxed, and the temperature was maintained for 20 minutes. Then, a solution in which 1 g of benzyl peroxide was dissolved in 100 g of ethyl acetate was added dropwise and reacted for 4 hours. Thereafter, a solution in which 1 g of benzyl peroxide was dissolved in 100 g of ethyl acetate was added dropwise, and the mixture was further reacted for 3 hours. Next, 400 g of toluene was stirred and mixed to obtain an adhesive solution (A) having a viscosity of 12000 cps. The solids content was 39.5% by weight.
[0086]
4.0 g of an isocyanate-based curing agent (manufactured by Nippon Polyurethane Co., trade name: Coronate L55E) was added to 100 g of this pressure-sensitive adhesive solution (A), mixed well, and then defoamed and coated on a PET film 1 subjected to a release treatment. Work was performed to form an adhesive layer having a thickness of 40 μm. Thereafter, the pressure-sensitive adhesive layer was immediately hot-laminated on one surface of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1 to obtain a flame-retardant pressure-sensitive adhesive sheet as shown in FIG.
[0087]
(Comparative Example 3)
A flame-retardant pressure-sensitive adhesive sheet was obtained in the same manner as in Example 20, except that the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1 was used instead of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1. .
As shown in FIG. 6, a test piece for evaluating the performance of the obtained flame-retardant pressure-sensitive adhesive sheet was formed on one of the pressure-sensitive adhesive surfaces of the flame-retardant pressure-sensitive adhesive sheet 2b obtained in Comparative Example 1 with soft chloride. This was prepared by laminating a vinyl resin 6 and bonding a polycarbonate plate 3 to the other adhesive surface of the flame-retardant adhesive sheet 2b.
[0088]
(Example 21)
Except that the flame-retardant pressure-sensitive adhesive sheet obtained in Example 4 was used instead of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1, it was difficult to apply the pressure-sensitive adhesive in the same manner as in Example 20. A flammable adhesive sheet was obtained.
[0089]
(Example 22)
Except that the flame-retardant pressure-sensitive adhesive sheet obtained in Example 7 was used instead of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1, an adhesive was applied to the flame-retardant pressure-sensitive adhesive sheet in the same manner as in Example 20. The layer was hot-laminated to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0090]
(Example 23)
An adhesive layer was laminated in the same manner as in Example 20 except that the flame-retardant pressure-sensitive adhesive sheet obtained in Example 10 was used instead of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1. A flammable adhesive tape was obtained.
[0091]
(Example 24)
Laminating the pressure-sensitive adhesive layer in the same manner as in Example 20 except that the flame-retardant pressure-sensitive adhesive sheet obtained in Example 12 was used instead of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1 A flammable adhesive sheet was obtained.
[0092]
(Example 25)
Laminating the pressure-sensitive adhesive layer in the same manner as in Example 20 except that the flame-retardant pressure-sensitive adhesive sheet obtained in Example 13 was used instead of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1 A flammable adhesive sheet was obtained.
[0093]
(Example 26)
Laminating the pressure-sensitive adhesive layer in the same manner as in Example 20 except that the flame-retardant pressure-sensitive adhesive sheet obtained in Example 16 was used instead of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1 A flammable adhesive sheet was obtained.
About the obtained flame-retardant pressure-sensitive adhesive sheet, flame retardancy, shear strength and T peel strength were measured in the same manner as in Example 20.
[0094]
(Example 27)
Laminating the pressure-sensitive adhesive layer in the same manner as in Example 20 except that the flame-retardant pressure-sensitive adhesive sheet obtained in Example 19 was used instead of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1 A flammable adhesive sheet was obtained.
[0095]
For the flame-retardant pressure-sensitive adhesive tapes obtained in Examples 20 to 27, the test methods used in Example 1 were partially modified to measure the flame retardancy, shear strength and T-peel strength as shown below. Table 2 shows the measurement results.
[0096]
<Shear strength>
As shown in FIG. 5, the adhesive sheet of width 20 mm × length 20 mm obtained in Example 4 was applied to a soft vinyl chloride resin plate 6 (Shore D hardness 50, width 25 mm × length 100 mm × thickness 5 mm). The surface on the side of the pressure-sensitive adhesive layer 5a is adhered, and the surface on the side of the flame-retardant pressure-sensitive adhesive sheet 2a is adhered to a polycarbonate plate 3 (25 mm in width × 100 mm in length × 2 mm in thickness) which has been treated with a primer. A test piece was prepared by heat aging, and the shear strength was measured using the test piece. The tensile speed was 50 mm / min.
[0097]
(Example 28)
A separable flask equipped with a condenser, a thermometer and a stirrer was charged with 900 g of 2-ethylhexyl acrylate, 100 g of acrylic acid, 0.2 g of n-dodecanethiol and 900 g of ethyl acetate, and heated to reflux under a nitrogen gas atmosphere. After warming and holding for 20 minutes, a solution of 1 g of benzyl peroxide dissolved in 100 g of ethyl acetate was added dropwise and reacted for 4 hours. Thereafter, a solution in which 1 g of benzyl peroxide was dissolved in 100 g of ethyl acetate was added dropwise, and the mixture was further reacted for 3 hours. Next, 400 g of toluene was stirred and mixed to obtain an adhesive solution (B) having a viscosity of 12000 cps. The solids content was 36.4% by weight.
[0098]
To 100 g of this pressure-sensitive adhesive solution (B), 0.2 g of hexamethylene diethylene urea (trade name, manufactured by Mutual Pharmaceutical Co., Ltd.) was added, and after sufficient mixing and stirring, defoaming and coating on a release-treated PET film were performed. Then, an adhesive layer having a thickness of 40 μm was formed. Then, the pressure-sensitive adhesive layers were immediately hot-laminated on both sides of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 7, to obtain a flame-retardant pressure-sensitive adhesive sheet as shown in FIG.
[0099]
(Example 29)
Using 950 g of 2-ethylhexyl acrylate, 50 g of acrylic acid, 0.2 g of n-dodecanethiol and 900 g of ethyl acetate, a pressure-sensitive adhesive solution (C) having a viscosity of 8900 cps and a solid content of 38% by weight was obtained in the same manner as in Example 28. . A pressure-sensitive adhesive layer having a thickness of 40 μm was formed using the pressure-sensitive adhesive solution (C). Then, this pressure-sensitive adhesive layer was laminated on both sides of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 7 to obtain a flame-retardant pressure-sensitive adhesive sheet.
[0100]
(Comparative Example 4)
A flame-retardant pressure-sensitive adhesive sheet was obtained in the same manner as in Example 28 except that the flame-retardant pressure-sensitive adhesive sheet obtained in Example 7 was used instead of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 7. .
[0101]
The flame-retardant pressure-sensitive adhesive tapes obtained in Examples 28 to 29 and Comparative Example 4 were measured for flame retardancy, shear strength and T peel strength by partially changing the method as described below.
[0102]
<Shear strength>
As shown in FIG. 9, a stainless plate 7 (width 50 mm × length 125 mm × thickness 1 mm) is attached to both sides of the flame-retardant adhesive sheet obtained in Example 9 having a width of 20 mm × length 20 mm to form a sheet 90. A test specimen was prepared by heat aging at 24 ° C. for 24 hours, and the shear strength was measured using the test specimen. The tensile speed was 50 mm / min.
[0103]
<T peel strength>
As shown in FIG. 10, aluminum foil 4 having a thickness of 300 μm was attached to both sides of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 9 having a width of 20 mm and a length of 70 mm, and heat-aged at 90 ° C. for 24 hours. A test piece was prepared, and the T-peel strength was measured using the test piece. The tensile speed was 200 mm / min.
[0104]
(Example 30)
Instead of 100 g of sepiolite fiber, crosslinked polymethyl methacrylate fine particles having an average particle diameter of 5 μm and a refractive index of 1.49 (trade name “Techpolymer MBX-5” manufactured by Sekisui Plastics Co., Ltd.) A partially photopolymerized thickening composition was obtained in the same manner as in Example 1 except that 100 g was used as a filler. The resulting partially photopolymerized thickening composition had a conversion of 4.9% and a viscosity of 2900 cps. The following steps were performed in the same manner as in Example 1 to obtain a flame-retardant pressure-sensitive adhesive sheet. The residual monomer of the obtained flame-retardant pressure-sensitive adhesive sheet was less than 0.1%, and the gel fraction was 85%.
With respect to the obtained flame-retardant pressure-sensitive adhesive sheet, flame retardancy, shear strength and T peel strength were measured in the same manner as in Example 1. Further, the transparency was visually evaluated.
[0105]
(Example 31)
Silica fine particles having an average particle diameter of 50 μm and a refractive index of 1.50 (trade name “MS GEL D-50-, manufactured by Dokai Chemical Co., Ltd.) are used instead of 100 g of the glass fibers subjected to the hydrophobic treatment. 0A ") A flame-retardant pressure-sensitive adhesive sheet was obtained in the same manner as in Example 2, except that 1000 g was used as the filler.
With respect to the obtained flame-retardant pressure-sensitive adhesive sheet, flame retardancy, shear strength and T peel strength were measured in the same manner as in Example 1. Further, the transparency was visually evaluated.
[0106]
(Example 32)
Instead of 100 g of the hydrophobized glass fiber, crosslinked polyethyl acrylate fine particles having an average particle size of 20 μm and a refractive index of 1.48 (trade name “Techpolymer EAX-”, manufactured by Sekisui Plastics Co., Ltd.) 15 ") A flame-retardant photopolymerizable composition was obtained in the same manner as in Example 3, except that 200 g was used as a filler. The following steps were performed in the same manner as in Example 3 to obtain a flame-retardant pressure-sensitive adhesive sheet.
With respect to the obtained flame-retardant pressure-sensitive adhesive sheet, flame retardancy, shear strength and T peel strength were measured in the same manner as in Example 1. Further, the transparency was visually evaluated.
[0107]
(Example 33)
Both surfaces of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 31 were subjected to a primer treatment, and the 100 μm-thick flame-retardant pressure-sensitive adhesive sheets obtained in Comparative Example 1 were transferred to each other to have a flame-retardant layer having a surface pressure-sensitive adhesive layer. A double-sided PSA sheet was obtained. The obtained flame-retardant double-sided pressure-sensitive adhesive sheet was bonded to a glass plate (width 25 mm × length 100 mm) and the shear strength was measured. Further, when a glass plate was attached to both sides and the transparency was visually confirmed, the obtained flame-retardant double-sided pressure-sensitive adhesive sheet had transparency.
[0108]
For the flame-retardant pressure-sensitive adhesive tapes obtained in the above Examples 30 to 33, in addition to the respective tests of the flame retardancy, shear strength and T-peel strength performed in Example 1, the transparency was evaluated by a visual test. The evaluation was given on a two-point scale, ○ when the article was transparent and the article behind it could be seen through, and × when the article could not be seen through the article.
[0109]
[Table 2]

[0110]
(Example 34)
400 g of 2-ethylhexyl acrylate, 500 g of isononyl acrylate, 50 g of N-vinylpyrrolidone, 50 g of alicyclic epoxy acrylate (trade name "Cyclomer A-200", manufactured by Daicel Huls) and hydrophilic silica (trade name, manufactured by Nippon Aerosil Co., Ltd.) "Aerosil 200") was stirred and mixed with a disperser at 1000 rpm for 4 hours to obtain a viscous liquid. 200 g of polyethylene fine particles (trade name “Flosen UF4”, manufactured by Sumitomo Seika Co., Ltd., average particle diameter: 25 μm) and 0.3 g of Irgacure 184 were added thereto, and the mixture was stirred and mixed until uniform, and then nitrogen gas was purged. Dissolved oxygen was removed. The following steps were performed in the same manner as in Example 1 to obtain a flame-retardant pressure-sensitive adhesive sheet having a thickness of about 1 mm.
[0111]
10.0 g of disproportionated rosin ester (trade name "Super Ester A-115" manufactured by Arakawa Chemical Co., Ltd.) was mixed with 100 g of the pressure-sensitive adhesive solution (A) obtained in Example 20, and dissolved. A pressure-sensitive adhesive was prepared by mixing and stirring 1.5 g of L55E (trade name), coated on a PET film that had been subjected to a release treatment, and dried to form a pressure-sensitive adhesive layer. Hot-lamination was performed on both sides to obtain a flame-retardant double-sided adhesive tape. The obtained flame-retardant double-sided pressure-sensitive adhesive tape was measured for flame retardancy and 180 ° peel strength by the following method.
[0112]
<180 ° peel strength>
One side of the obtained flame-retardant double-sided pressure-sensitive adhesive tape was affixed as a backing film with a PET film (thickness: 38 μm) that had been subjected to corona discharge treatment to obtain a single-sided pressure-sensitive adhesive tape. As an adherend, it was adhered to a polypropylene (PP) plate (50 mm in width × 125 mm in length × 1 mm in thickness) according to the 180 ° peeling method of JIS Z 0237, and the 180 ° peel strength was measured.
[0113]
(Comparative Example 5)
An adhesive tape was obtained in the same manner as in Example 34 except that acryloyloxymethyl (dimethyl) phosphate and polyethylene fine particles were not used.
With respect to the obtained pressure-sensitive adhesive tape, flame retardancy and 180 ° peel strength were measured in the same manner as in Example 34.
[0114]
Table 3 below shows the measurement results of the flame retardancy and the 180 ° peel strength of Example 34 and Comparative Example 5.
[0115]
[Table 3]

[0116]
【The invention's effect】
Since the flame-retardant photopolymerizable composition of the present invention is constituted as described above, high flame retardancy is stably maintained for a long time, and the flame-retardant photopolymerizable composition has excellent adhesive strength such as shear strength and peel strength. A flammable pressure-sensitive adhesive tape can be obtained, and by using this flame-retardant pressure-sensitive adhesive tape, joining work of a structure or the like can be easily performed. According to the present invention, a flame-retardant pressure-sensitive adhesive tape having excellent transparency can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a flame-retardant pressure-sensitive adhesive sheet and a PET film when a flame-retardant pressure-sensitive adhesive sheet is produced in Example 1.
FIG. 2 is a sectional view of a test piece used when measuring the shear strength of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1.
FIG. 3 is a sectional view of a test piece used when measuring the T-peel strength of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 1.
FIG. 4 is a cross-sectional view showing a configuration of a pressure-sensitive adhesive sheet, a pressure-sensitive adhesive layer, and a PET film when a flame-retardant pressure-sensitive adhesive sheet is produced in Example 4.
FIG. 5 is a sectional view of a test piece used when measuring the shear strength of the flame-retardant pressure-sensitive adhesive sheet obtained in Example 4.
FIG. 6 is a cross-sectional view of a test piece used when measuring shear strength in Comparative Example 4.
FIG. 7 is a cross-sectional view of a test piece used when measuring shear strength in Comparative Example 5.
FIG. 8 is a cross-sectional view showing the structure of an adhesive sheet, an adhesive layer, and a PET film when a pressure-sensitive adhesive sheet is obtained in Example 35.
FIG. 9 is a cross-sectional view of a test piece used when measuring shear strength in Example 35.
FIG. 10 is a cross-sectional view of a test piece used when measuring T peel strength in Example 35.
[Explanation of symbols]
1,1 'PET film
2a, 2b, 2c adhesive sheet
3 Polycarbonate plate
4 Aluminum foil
5a, 5b adhesive layer
6 Soft vinyl chloride resin plate
7 Stainless steel plate

Claims (4)

50 to 98% by weight of one or more (meth) acrylic acid ester monomers (a) selected from (meth) acrylic acid esters having an alkyl group having 1 to 12 carbon atoms;
100 parts by weight of a monomer mixture having a polar group and containing 50 to 2% by weight of one or more monomers (b) selected from monomers copolymerizable with the (meth) acrylate monomer (a) Against
3 to 20 parts by weight of a compound (c) copolymerizable with the (meth) acrylic acid ester monomer (a) and the monomer (b) and having a phosphorus element in a molecule;
Flame retardant photopolymerizable composition containing 0.01 to 5 parts by weight of photopolymerization initiator (d) and at least one filler selected from the group consisting of the following (e1) to (e9):
Fibrous filler (e1) having an average diameter of 0.2 to 20 μm and an average fiber length of 5 μm to 1 mm;
Porous fine particles (e2) having an average particle diameter of 0.5 to 150 μm;
Non-polar resin fine particles (e3) having an average particle diameter of 5 to 150 μm;
Organic fine particles (e4) having an average particle diameter of 5 to 100 µm and a glass transition temperature of 90 ° C or higher;
Flat fine particles (e5) having an average particle diameter of 1 to 50 μm and an aspect ratio of 20 to 40;
Fine particles (e6) having an average particle size of 1 to 150 μm and containing an aluminosilicate compound as a main component;
Silica-based fine particles (e7) having an average particle diameter of 10 to 150 μm and a smooth particle surface;
Silica-based fine particles (e8) having an average particle diameter of 10 to 150 μm and a hydrophobic treatment on the particle surface; and an average particle diameter of 5 to 150 μm and a refractive index of 1.47 to 1.51. (E9). The compound (c) copolymerizable with the (meth) acrylic acid ester monomer (a) and the monomer (b) according to claim 1 and having a phosphorus element in a molecule is represented by the following structural formula (I) or ( A flame-retardant photopolymerizable composition which is a compound represented by II).

A flame-retardant pressure-sensitive adhesive tape obtained by applying the flame-retardant photopolymerizable composition according to claim 1 or 2 into a sheet, and then irradiating the sheet-shaped photopolymerizable composition with light. A flame-retardant pressure-sensitive adhesive tape obtained by laminating a pressure-sensitive adhesive layer on at least one surface of the flame-retardant pressure-sensitive adhesive tape according to claim 3.

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