JP4132282B2 - Gradient index type optical resin material - Google Patents

Description

【００２６】
【化２】
Ｆ−（−Φ² −Ｓ−）_h −Φ¹ 式５
Φ^k （−Ｓ−Φ¹ ）_k 式６
（Φ¹ ）_p −Ｍ 式７
（Φ¹ −Ｓ−）_q −Ｍ 式８
【００２７】
【化３】

【００２８】
炭素環または複素環の３個以上から構成されている縮合多環式化合物であって、かつ水素原子の一部または全部がフッ素原子またはフッ素含有基に置換されている含フッ素縮合多環式化合物における炭素環および複素環としては、４員環以上のものが好ましく、４〜６員環がより好ましい。複素環を構成する好ましい原子としては、炭素原子、窒素原子、酸素原子、硫黄原子、リン原子などから選ばれる。
【００２９】
含フッ素縮合多環式化合物としては、ペルフルオロフルオレン、ペルフルオロフェナレン、ペルフルオロフェナントレン、ペルフルオロアントラセン、ペルフルオロトリフェニレン、ペルフルオロピレン、ペルフルオロクリセン、ペルフルオロナフタセンなどの３〜４個の炭素環から構成されている含フッ素縮合多環式炭化水素または以下の式１３または式１４で表される含フッ素縮合多環式化合物が好ましい。
【００３０】
【化４】

【００３１】
屈折率分布型光学樹脂材料の透明性を阻害しない観点から、ペルフルオロフルオレン、ペルフルオロフェナレン、ペルフルオロフェナントレン、ペルフルオロアントラセンなどの３個の炭素環から構成されている含フッ素縮合多環式炭化水素がより好ましい。
【００３２】
化合物（Ｂ）としては、熱的安定性、重合体（Ａ）との溶解性の高いものおよび屈折率分布型光学樹脂材料の透明性を阻害しないものから選ぶことが好ましい。
このような化合物（Ｂ）としては、２個以上の含フッ素環が少なくともトリアジン環を含む結合で結合した含フッ素非縮合多環式化合物が特に好ましい。トリアジン環としては、１，２，３−トリアジン環、１，２，４−トリアジン環および１，３，５−トリアジン環が挙げられ、１，３，５−トリアジン環が好ましい。
【００３３】
本発明における重合体（Ａ）は、非結晶性であり、かつ近赤外光で光吸収が起こるＣ−Ｈ結合を実質的に有しない重合体である。重合体（Ａ）としては、Ｃ−Ｈ結合を有しない非結晶性の含フッ素重合体であれば特に限定されないが、主鎖に含フッ素脂肪族環構造を有する含フッ素重合体が好ましい。
【００３４】
主鎖に含フッ素脂肪族環構造を有するとは、脂肪族環を構成する炭素原子の１以上が主鎖を構成する炭素連鎖中の炭素原子であり、かつ脂肪族環を構成する炭素原子の少なくとも一部にフッ素原子またはフッ素含有基が結合している構造を有することを意味する。含フッ素脂肪族環構造としては、含フッ素脂肪族エーテル環構造がさらに好ましい。
【００３５】
重合体（Ａ）の溶融状態における粘度は、溶融温度２００〜３００℃において１０³ 〜１０⁵ ポアズが好ましい。溶融粘度が高すぎると溶融紡糸が困難なうえ、屈折率分布の形成に必要な、化合物（Ｂ）の拡散が起こりにくくなり屈折率分布の形成が困難になる。また、溶融粘度が低すぎると実用上問題が生じる。すなわち、電子機器や自動車等での光伝送体として用いられる場合に高温にさらされ軟化し、光の伝送性能が低下する。
重合体（Ａ）の数平均分子量は１×１０⁴ 〜５×１０⁶ が好ましく、５×１０⁴ 〜１×１０⁶ がより好ましい。分子量が小さすぎると耐熱性を阻害することがあり、大きすぎると屈折率分布を有する光伝送体の形成が困難になる。
【００３６】
含フッ素脂肪族環構造を有する重合体としては、含フッ素環構造を有する単量体を重合して得られるものや、２つ以上の重合性二重結合を有する含フッ素単量体を環化重合して得られる主鎖に含フッ素脂肪族環構造を有する重合体が好適である。
【００３７】
含フッ素脂肪族環構造を有する単量体を重合して得られる主鎖に含フッ素脂肪族環構造を有する重合体は、特公昭６３−１８９６４などにより知られている。すなわち、ペルフルオロ（２，２−ジメチル−１，３−ジオキソール）などの含フッ素脂肪族環構造を有する単量体を単独重合することにより、またこの単量体とテトラフルオロエチレン、クロロトリフルオロエチレン、ペルフルオロ（メチルビニルエーテル）などのラジカル重合性とを共重合させることにより主鎖に含フッ素脂肪族環構造を有する重合体が得られる。
【００３８】
また、２つ以上の重合性二重結合を有する含フッ素単量体を環化重合して得られる、主鎖に含フッ素脂肪族環構造を有する重合体は、特開昭６３−２３８１１１や特開昭６３−２３８１１５などにより知られている。すなわち、ペルフルオロ（アリルビニルエーテル）やペルフルオロ（ブテニルビニルエーテル）などを環化重合することにより、またはこのような単量体とテトラフルオロエチレン、クロロトリフルオロエチレン、ペルフルオロ（メチルビニルエーテル）などのラジカル重合性とを共重合させることにより主鎖に含フッ素脂肪族環構造を有する重合体が得られる。
【００３９】
また、ペルフルオロ（２，２−ジメチル−１，３−ジオキソール）などの含フッ素脂肪族環構造を有する単量体とペルフルオロ（アリルビニルエーテル）やペルフルオロ（ブテニルビニルエーテル）などの２つ以上の重合性二重結合を有する含フッ素単量体とを共重合させることによっても主鎖に含フッ素脂肪族環構造を有する重合体が得られる。
【００４０】
含フッ素脂肪族環構造を有する重合体としては、含フッ素脂肪族環構造を有する重合体の全重合単位に対して含フッ素脂肪族環構造を有する重合単位を２０モル％以上、特には４０モル％以上含有するものが透明性、機械的特性などの面から好ましい。
【００４１】
上記の含フッ素脂肪族環構造を有する重合体としては、具体的には以下の式１５〜１８のいずれかで表される繰り返し単位を有するものが例示される。ただし、式１５〜１８において、ｈは０〜５の整数、ｉは０〜４の整数、ｊは０または１、ｈ＋ｉ＋ｊは１〜６、ｓは０〜５の整数、ｔは０〜４の整数、ｕは０または１、ｓ＋ｔ＋ｕは１〜６、ｐ、ｑ、ｒはそれぞれ独立に０〜５の整数、ｐ＋ｑ＋ｒは１〜６、Ｒ¹ 〜Ｒ⁶ はそれぞれ独立にフッ素原子、塩素原子、重水素原子（Ｄ）またはトリフルオロメチル基である。
なお、これらの含フッ素脂肪族環構造を有する重合体中のフッ素原子は、屈折率を高めるために一部塩素原子で置換されていてもよい。
【００４２】
【化５】

【００４３】
含フッ素脂肪族環構造を有する単量体としては、以下の式１９〜２１のいずれかで表される化合物から選ばれる単量体が好ましい。ただし、式１９〜２１において、Ｒ⁷ 〜Ｒ¹⁸はそれぞれ独立にフッ素原子、塩素原子、重水素原子またはトリフルオロメチル基であるか、または、Ｒ⁹ とＲ¹⁰、Ｒ¹³とＲ¹⁴およびＲ¹⁷とＲ¹⁸はそれぞれ共同して−（ＣＦ₂ ）₄ −、−（ＣＦ₂ ）₃ −、−（ＣＦ₂ ）₂ −、−ＣＦ₂ −Ｏ−ＣＦ₂ −、−（ＣＦ₂ ）₂ −Ｏ−ＣＦ₂ −、−Ｏ−（ＣＦ₂ ）₂ −および−Ｏ−（ＣＦ₂ ）₃ −からなる群から選ばれる２価の基を形成してもよい。
【００４４】
【化６】

【００４５】
式１９〜２１のいずれかで表される化合物の具体例としては、以下の式２２〜２９のいずれかで表される化合物などが挙げられる。
【００４６】
【化７】

【００４７】
２つ以上の重合性二重結合を有する含フッ素単量体としては、以下の式３０〜３２のいずれかで表される化合物が好ましい。ただし、式３０〜３２において、Ｙ¹ 〜Ｙ¹⁰、Ｚ¹ 〜Ｚ⁸ およびＷ¹ 〜Ｗ⁸ は、それぞれ独立にフッ素原子、塩素原子、重水素原子またはトリフルオロメチル基である。
【００４８】
【化８】
ＣＹ¹ Ｙ² ＝ＣＹ³ ＯＣＹ⁴ Ｙ⁵ ＣＹ⁶ Ｙ⁷ ＣＹ⁸ ＝ＣＹ⁹ Ｙ¹⁰ 式３０
ＣＺ¹ Ｚ² ＝ＣＺ³ ＯＣＺ⁴ Ｚ⁵ ＣＺ⁶ ＝ＣＺ⁷ Ｚ⁸ 式３１
ＣＷ¹ Ｗ² ＝ＣＷ³ ＯＣＷ⁴ Ｗ⁵ ＯＣＷ⁶ ＝ＣＷ⁷ Ｗ⁸ 式３２
【００４９】
式３０〜３２のいずれかで表される化合物の具体例としては、以下の化合物などが挙げられる。
ＣＦ₂ ＝ＣＦＯＣＦ₂ ＣＦ₂ ＣＦ＝ＣＦ₂
ＣＦ₂ ＝ＣＦＯＣＣｌ₂ ＣＦ₂ ＣＦ＝ＣＦ₂
ＣＦ₂ ＝ＣＦＯＣＦ₂ ＣＦ₂ ＣＣｌ＝ＣＦ₂
ＣＦ₂ ＝ＣＦＯＣＦ₂ ＣＦＣｌＣＦ＝ＣＦ₂
ＣＦ₂ ＝ＣＦＯＣＦ₂ ＣＦ₂ ＣＦ＝ＣＦＣｌ
ＣＦ₂ ＝ＣＦＯＣＦ₂ ＣＦ（ＣＦ₃ ）ＣＦ＝ＣＦ₂
ＣＦ₂ ＝ＣＦＯＣＦ₂ ＣＦ（ＣＦ₃ ）ＣＣｌ＝ＣＦ₂
ＣＦ₂ ＝ＣＦＯＣＦ₂ ＣＦ＝ＣＦ₂
ＣＦ₂ ＝ＣＦＯＣＦ（ＣＦ₃ ）ＣＦ＝ＣＦ₂
ＣＦ₂ ＝ＣＦＯＣ（ＣＦ₃ ）₂ ＣＦ＝ＣＦ₂
ＣＦ₂ ＝ＣＦＯＣＦ₂ ＯＣＦ＝ＣＦ₂
ＣＦ₂ ＝ＣＣｌＯＣＦ₂ ＯＣＣｌ＝ＣＦ₂
ＣＦ₂ ＝ＣＦＯＣＣｌ₂ ＯＣＦ＝ＣＦ₂
ＣＦ₂ ＝ＣＦＯＣ（ＣＦ₃ ）₂ ＯＣＦ＝ＣＦ₂
【００５０】
本発明の光学樹脂材料を製造するにあたり、樹脂の成形と屈折率分布の形成は同時であっても別々であってもよい。例えば、紡糸や押し出し成形などにより樹脂を成形すると同時に屈折率分布を形成して本発明光学樹脂材料を製造できる。また、紡糸や押し出し成形で樹脂の成形を行った後、屈折率分布を形成できる。さらに、屈折率分布を有するプリフォーム（母材）を製造し、このプリフォームを成形（例えば紡糸）して光ファイバなどの光学樹脂材料を製造できる。なお、前記のように本発明光学樹脂材料は、上記屈折率分布を有するプリフォームをも意味する。
【００５１】
本発明の光学樹脂材料は屈折率分布型光ファイバであることが最も好ましい。この光ファイバにおいて、化合物（Ｂ）は重合体（Ａ）よりも高屈折率の物質であるため、化合物（Ｂ）が光ファイバの中心から周辺方向に沿って濃度が低下する濃度勾配を有して分布している。これにより、光ファイバの中心から周辺方向に沿って屈折率が低下する屈折率分布となる。化合物（Ｂ）の濃度分布は、通常化合物（Ｂ）を溶融状態の重合体（Ａ）の中心に配置し、周辺方向に向かって化合物（Ｂ）を拡散させることにより形成できる。
【００５２】
化合物（Ｂ）は重合体（Ａ）との比較において屈折率が０．００５以上高いので、光学樹脂材料中の屈折率の最大値ｎと最小値ｍの屈折率差を大きくできる。すなわち「（ｎ² −ｍ² ）^1/2 」で表される開口数ＮＡを０．２０以上とすることができる。化合物（Ｂ）は重合体（Ａ）との比較において屈折率が０．０１以上高いことが好ましい。化合物（Ｂ）の屈折率は１．４５以上が好ましく、１．４７以上がより好ましい。
【００５３】
一般に重合体に低分子量化合物を添加すると重合体のＴ_g が低下する。屈折率のあまり大きくない化合物を屈折率差の形成材として用いた場合には、重合体中への含有量を多くしなければならず、その結果Ｔ_g が低下し耐熱性が低下する。
【００５４】
本発明における化合物（Ｂ）は屈折率が高いため少量の添加、例えば光学樹脂材料中心部の化合物（Ｂ）の濃度が１５重量％以下となる添加量であっても、目的の屈折率差を形成でき、Ｔ_g の低下が少ない利点がある。
また、化合物（Ｂ）のＴ_g が高いため、光学樹脂材料中心部のＴ_g を７０℃以上とすることができる。化合物（Ｂ）の種類によっては光学樹脂材料中心部のＴ_g を９０℃以上とすることもできる。これにより、本発明の光学樹脂材料の耐熱性が飛躍的に向上する。
【００５５】
また、化合物（Ｂ）は、重合体（Ａ）に対する溶解性が良好で、その飽和溶解度は５〜２０重量％である。溶解性の尺度である溶解性パラメータ（ＳＰ値）は、重合体（Ａ）が６〜７（ｃａｌ／ｃｍ³ ）^1/2 であるのに対して、化合物（Ｂ）は８〜１０（ｃａｌ／ｃｍ³ ）^1/2 と近い値を有するため溶解性がよいと考えられる。
重合体（Ａ）に対する化合物（Ｂ）の含有量が上記飽和溶解度以下の場合においては、本発明の光学樹脂材料の透明性は良好であり、ミクロな相分離や化合物（Ｂ）の微結晶などにより生じる光散乱が少ない。
【００５６】
本発明の光学樹脂材料である光伝送体は、波長７００〜１６００ｎｍで、１００ｍの伝送損失が１５ｄｂ以下とすることができる。波長７００〜１６００ｎｍという比較的長波長において、このような低レベルの伝送損失であることはきわめて有利である。
すなわち、石英光ファイバと同じ波長を使えることにより、石英光ファイバとの接続が容易であり、また波長７００〜１６００ｎｍよりも短波長を使わざるをえない従来のプラスチック光ファイバに比べ、安価な光源ですむ利点がある。
【００５７】
光伝送体の伝送特性において、上記伝送損失とともに重要な特性として伝送帯域がある。大量の情報を高速で伝送するために伝送帯域が広いことが望まれる。現在、長距離通信において用いられている石英系シングルモードファイバは伝送帯域が数１０ＧＨｚ・ｋｍの広い伝送帯域を有する。
【００５８】
一方、プラスチック光ファイバはファイバ径が太く光源・受光素子との接続またはファイバ同士の接続が容易なことから安価な短距離通信システムの構築への期待が高まっている。
【００５９】
通常のプラスチック光ファイバはステップインデックス型であり、伝送帯域は数ＭＨｚ・ｋｍ程度と狭い。これを解決するために、本発明のような伝送帯域のより広い屈折率分布型プラスチック光ファイバが提案されている。この屈折率分布型プラスチック光ファイバにおいては、この屈折率分布が熱的に安定でないと、結果として伝送帯域が低下する。
【００６０】
本発明の光学樹脂材料は耐熱性が飛躍的に向上しているので、屈折率分布の熱的な安定性が高く、室温以上の高温に長期間さらされた場合においても、伝送帯域の低下を防止できる。
【００６１】
【実施例】
次に、本発明を実施例によって具体的に説明するが、本発明はこれらに限定されない。以下の例において、例１〜３は重合体（Ａ）の合成例、例４〜１０および例１６〜１７は実施例、例１１〜１５は比較例である。
【００６２】
「例１」
７５０ｇのペルフルオロ（ブテニルビニルエーテル）［ＰＢＶＥ］、４ｋｇのイオン交換水、２６０ｇのメタノールおよび３．７ｇの（（ＣＨ₃ ）₂ ＣＨＯＣＯＯ）₂ を、内容積５Ｌのガラスフラスコに入れた。系内を窒素で置換した後、４０℃で２２時間懸濁重合を行い、数平均分子量約５×１０⁴ の重合体を６９０ｇ得た。この重合体をフッ素／窒素混合ガス（フッ素ガス濃度２０容量％）雰囲気中で２５０℃、５時間処理することにより光透過性および熱安定性の良好な重合体（以下、重合体Ａ１という）を得た。
【００６３】
重合体Ａ１の固有粘度［η］は、ペルフルオロ（２−ブチルテトラヒドロフラン）［ＰＢＴＨＦ］中３０℃で０．３であった。重合体Ａ１のＴ_g は１０８℃であり、室温ではタフで透明なガラス状の重合体であった。また屈折率は１．３４２、ＳＰ値は６．６（ｃａｌ／ｃｍ³ ）^1/2 であった。
【００６４】
「例２」
１７３ｇのＰＢＶＥ、２７ｇのペルフルオロ（２，２−ジメチル−１，３−ジオキソール）［ＰＤＤ］、２００ｇのＰＢＴＨＦおよび重合開始剤として２ｇの（（ＣＨ₃ ）₂ ＣＨＯＣＯＯ）₂ を、内容積１Ｌのステンレス製オートクレーブに入れた。系内を窒素で置換した後、４０℃で２０時間重合を行い、数平均分子量約１．５×１０⁵ の透明な重合体２０ｇを得た。この重合体をフッ素／窒素混合ガス（フッ素ガス濃度２０容量％）雰囲気中で２５０℃、５時間処理することにより光透過性および熱安定性の良好な重合体（以下、重合体Ａ２という）を得た。重合体Ａ２のＴ_g は１５０℃、屈折率は１．３２５、ＳＰ値は６．５（ｃａｌ／ｃｍ³ ）^1/2 であった。
【００６５】
「例３」
ＰＤＤとテトラフルオロエチレンを重量比８０：２０でＰＢＴＨＦを溶媒として用いてラジカル重合し、Ｔ_g が１６０℃で数平均分子量が約１．７×１０⁵ の重合体を得た。この重合体をフッ素／窒素混合ガス（フッ素ガス濃度２０容量％）雰囲気中で２５０℃、５時間処理することにより光透過性および熱安定性の良好な重合体（以下、重合体Ａ３という）を得た。重合体Ａ３は無色透明であり、屈折率は１．３０５、ＳＰ値は６．３（ｃａｌ／ｃｍ³ ）^1/2 であった。
【００６６】
「例４」
重合体Ａ１とペルフルオロ（テトラフェニルスズ）との混合物［後者を混合物中７重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ａという）を得た。成形体ａの屈折率は１．３５７、Ｔ_g は９１℃であった。
【００６７】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この円筒管中空部に成形体ａを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２３０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで２００ｄＢ／ｋｍ、８５０ｎｍで１５０ｄＢ／ｋｍ、１３００ｎｍで１２０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【００６８】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布をインターファコ干渉顕微鏡により測定し、保存前の屈折率分布と比較したところ変化は見られなかった。さらに、以下のようなパルス法により伝送帯域を測定することにより伝送特性を評価した。
【００６９】
すなわち、パルスジェネレータを用いてパルスレーザ光を発振させ、これを光ファイバに入射し、出射光をサンプリングオシロスコープで検出した。この検出信号をフーリエ変換して周波数特性を解析することにより伝送帯域を測定した。光ファイバを７０℃、１０００時間保存した後に伝送帯域を測定したところ、保存前後ともに２６０ＭＨｚ・ｋｍで、帯域の低下が起こらないことから耐熱性が良好であることが確認された。
【００７０】
「例５」
重合体Ａ１とペルフルオロ（トリフェニルホスフィン）との混合物［後者を混合物中７重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｂという）を得た。成形体ｂの屈折率は１．３５７、Ｔ_g は８８℃であった。
【００７１】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｂを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２３０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで２００ｄＢ／ｋｍ、８５０ｎｍで１５０ｄＢ／ｋｍ、１３００ｎｍで１２０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【００７２】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布をインターファコ干渉顕微鏡により測定し、保存前の屈折率分布と比較したところ特に変化は見られなかった。また、例４と同様なパルス法により伝送帯域を測定し、保存前後の特性を比較したところいずれも２４０ｄＢ・ｋｍで帯域の低下が起こらないことから耐熱性が良好であることが確認された。
【００７３】
「例６」
重合体Ａ１と１，４−ビス（ペルフルオロフェニルチオ）テトラフルオロベンゼンとの混合物［後者を混合物中５重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｃという）を得た。成形体ｃの屈折率は１．３５７、Ｔ_g は８５℃であった。
【００７４】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｃを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２３０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで２００ｄＢ／ｋｍ、８５０ｎｍで１５０ｄＢ／ｋｍ、１３００ｎｍで１２０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【００７５】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布をインターファコ干渉顕微鏡により測定し、保存前の屈折率分布と比較したところ特に変化は見られなかった。また、例４と同様なパルス法により伝送帯域を測定し、保存前後の特性を比較したところいずれも２５０ｄＢ・ｋｍで帯域の低下が起こらないことから耐熱性が良好であることが確認された。
【００７６】
「例７」
重合体Ａ１とペルフルオロ（２，４，６−トリフェニル−１，３，５−トリアジン）との混合物［後者を混合物中５重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｄという）を得た。成形体ｄの屈折率は１．３５７、Ｔ_g は９５℃であった。
【００７７】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｄを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２４０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで１２０ｄＢ／ｋｍ、８５０ｎｍで１００ｄＢ／ｋｍ、１３００ｎｍで８０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【００７８】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布をインターファコ干渉顕微鏡により測定し、保存前の屈折率分布と比較したところ特に変化は見られなかった。また、例４と同様なパルス法により伝送帯域を測定し、保存前後の特性を比較したところいずれも３００ｄＢ・ｋｍで帯域の低下が起こらないことから耐熱性が良好であることが確認された。
【００７９】
「例８」
重合体Ａ１とペルフルオロテルフェニルとの混合物［後者を混合物中５重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｅという）を得た。成形体ｅの屈折率は１．３５７、Ｔ_g は９５℃であった。
【００８０】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｅを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２３０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで１７０ｄＢ／ｋｍ、８５０ｎｍで１４０ｄＢ／ｋｍ、１３００ｎｍで１１０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【００８１】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布をインターファコ干渉顕微鏡により測定し、保存前の屈折率分布と比較したところ特に変化は見られなかった。また、例４と同様なパルス法により伝送帯域を測定し、保存前後の特性を比較したところいずれも２６０ｄＢ・ｋｍで帯域の低下が起こらないことから耐熱性が良好であることが確認された。
【００８２】
「例９」
重合体Ａ１とペルフルオロクァテルフェニルとの混合物［後者を混合物中５重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｆという）を得た。成形体ｆの屈折率は１．３５７、Ｔ_g は９３℃であった。
【００８３】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｆを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２４０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで１９０ｄＢ／ｋｍ、８５０ｎｍで１５０ｄＢ／ｋｍ、１３００ｎｍで１２０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【００８４】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布をインターファコ干渉顕微鏡により測定し、保存前の屈折率分布と比較したところ特に変化は見られなかった。また、例４と同様なパルス法により伝送帯域を測定し、保存前後の特性を比較したところいずれも２８０ｄＢ・ｋｍで帯域の低下が起こらないことから耐熱性が良好であることが確認された。
【００８５】
「例１０」
重合体Ａ１とペルフルオロアントラセンとの混合物［後者を混合物中５重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｇという）を得た。成形体ｇの屈折率は１．３５７、Ｔ_g は９５℃であった。
【００８６】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｇを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２４０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで１９０ｄＢ／ｋｍ、８５０ｎｍで１５０ｄＢ／ｋｍ、１３００ｎｍで１２０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【００８７】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布をインターファコ干渉顕微鏡により測定し、保存前の屈折率分布と比較したところ特に変化は見られなかった。また、例４と同様なパルス法により伝送帯域を測定し、保存前後の特性を比較したところいずれも３１０ｄＢ・ｋｍで帯域の低下が起こらないことから耐熱性が良好であることが確認された。
【００８８】
「例１１」
重合体Ａ１とクロロトリフルオロエチレンオリゴマー（平均分子量８５０、屈折率１．４１）との混合物［後者を混合物中１５重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｈという）を得た。成形体ｈの屈折率は１．３５７、Ｔ_g は７５℃であった。
【００８９】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｈを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２３０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する屈折率分布型光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで１１０ｄＢ／ｋｍ、８５０ｎｍで１００ｄＢ／ｋｍ、１３００ｎｍで８０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【００９０】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布を干渉顕微鏡により測定し、保存前の屈折率分布と比較したところコアの中心付近で屈折率の低下が見られた。また、これに伴い伝送帯域の低下が見られ、保存前に２６０ＭＨｚ・ｋｍであったものが保存後には１６０ＭＨｚ・ｋｍに低下していた。
【００９１】
「例１２」
重合体Ａ１とアルドリッチ社製ペルフルオロビフェニル（屈折率１．４５）との混合物［後者を混合物中７重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｉという）を得た。成形体ｉの屈折率は１．３５７、Ｔ_g は７３℃であった。
【００９２】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｉを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２３０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する屈折率分布型光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで１５０ｄＢ／ｋｍ、８５０ｎｍで１２０ｄＢ／ｋｍ、１３００ｎｍで１００ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【００９３】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布を干渉顕微鏡により測定し、保存前の屈折率分布と比較したところコアの中心付近で屈折率の低下が見られた。これに伴い、伝送帯域の低下が見られ、保存前に２００ＭＨｚ・ｋｍであったものが保存後には１１０ＭＨｚ・ｋｍに低下していた。
【００９４】
「例１３」
重合体Ａ１とアルドリッチ社製ペルフルオロ（ジフェニルスルフィド）との混合物［後者を混合物中６重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｊという）を得た。成形体ｊの屈折率は１．３５７、Ｔ_g は７７℃であった。
【００９５】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｊを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２３０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する屈折率分布型光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで１９０ｄＢ／ｋｍ、８５０ｎｍで１５０ｄＢ／ｋｍ、１３００ｎｍで１２０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【００９６】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布を干渉顕微鏡により測定し、保存前の屈折率分布と比較したところコアの中心付近で屈折率の低下が見られた。これに伴い、伝送帯域の低下が見られ、保存前に２６０ＭＨｚ・ｋｍであったものが保存後には１８０ＭＨｚ・ｋｍに低下していた。
【００９７】
「例１４」
重合体Ａ１とアルドリッチ社製ペルフルオロナフタレン( 屈折率１．４８) との混合物［後者を混合物中６重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｋという）を得た。成形体ｋの屈折率は１．３５７、Ｔ_g は７６℃であった。
【００９８】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｋを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２３０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する屈折率分布型光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで１８０ｄＢ／ｋｍ、８５０ｎｍで１５０ｄＢ／ｋｍ、１３００ｎｍで１１０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【００９９】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布を干渉顕微鏡により測定し、保存前の屈折率分布と比較したところコアの中心付近で屈折率の低下が見られた。これに伴い、伝送帯域の低下が見られ、保存前に２２０ＭＨｚ・ｋｍであったものが保存後には１１０ＭＨｚ・ｋｍに低下していた。
【０１００】
「例１５」
重合体Ａ１とＰＣＲ社製１，３，５−トリクロロ−２，４，６−トリフルオロベンゼンとの混合物［後者を混合物中６重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｍという）を得た。成形体ｍの屈折率は１．３５５、Ｔ_g は７９℃であった。
【０１０１】
次に、重合体Ａ１のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｍを挿入し２００℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２３０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する屈折率分布型光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで２１０ｄＢ／ｋｍ、８５０ｎｍで１７０ｄＢ／ｋｍ、１３００ｎｍで１３０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【０１０２】
この光ファイバを７０℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布を干渉顕微鏡により測定し、保存前の屈折率分布と比較したところコアの中心付近で屈折率の低下が見られた。これに伴い、伝送帯域の低下が見られ、保存前に２５０ＭＨｚ・ｋｍであったものが保存後には１７０ＭＨｚ・ｋｍに低下していた。
【０１０３】
「例１６」
重合体Ａ２とペルフルオロ（２，４，６−トリフェニル−１，３，５−トリアジン）との混合物［後者を混合物中５重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｎという）を得た。成形体ｎの屈折率は１．３４０、Ｔ_g は１３０℃であった。
【０１０４】
次に、重合体Ａ２のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｎを挿入し２３０℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２７０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで２５０ｄＢ／ｋｍ、８５０ｎｍで２００ｄＢ／ｋｍ、１３００ｎｍで１７０ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【０１０５】
この光ファイバを８５℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布をインターファコ干渉顕微鏡により測定し、保存前の屈折率分布と比較したところ特に変化は見られなかった。また、例４と同様なパルス法により伝送帯域を測定し、保存前後の特性を比較したところいずれも２８０ｄＢ・ｋｍで帯域の低下が起こらないことから耐熱性が良好であることが確認された。
【０１０６】
「例１７」
重合体Ａ３とペルフルオロ（２，４，６−トリフェニル−１，３，５−トリアジン）との混合物［後者を混合物中５重量％含む］をガラス封管中に仕込み、２５０℃で溶融成形し円柱状の成形体（以下、成形体ｐという）を得た。成形体ｐの屈折率は１．３２０、Ｔ_g は１４０℃であった。
【０１０７】
次に、重合体Ａ３のみからなる円筒管を溶融成形により作成し、この中空部に成形体ｐを挿入し２３０℃に加熱して合体させることによりプリフォームを得た。このプリフォームを２７０℃で溶融紡糸することにより、屈折率が中心部から周辺部に向かって徐々に低下する光ファイバが得られた。得られた光ファイバの光伝送特性は、７８０ｎｍで３００ｄＢ／ｋｍ、８５０ｎｍで２５０ｄＢ／ｋｍ、１３００ｎｍで２００ｄＢ／ｋｍであり、可視光から近赤外光までの光を良好に伝達できる光ファイバであることを確かめた。
【０１０８】
この光ファイバを８５℃のオーブン中に１０００時間保存した後、取り出してから屈折率分布をインターファコ干渉顕微鏡により測定し、保存前の屈折率分布と比較したところ特に変化は見られなかった。また、例４と同様なパルス法により伝送帯域を測定し、保存前後の特性を比較したところいずれも２６０ｄＢ・ｋｍで帯域の低下が起こらないことから耐熱性が良好であることが確認された。
【０１０９】
【発明の効果】
本発明における化合物（Ｂ）は屈折率が高いので、少量の添加であっても、目的の屈折率差を形成でき、化合物（Ｂ）の添加によるＴ_g の低下が少ない利点がある。この利点および化合物（Ｂ）のＴ_g が高いことにより、本発明の光学樹脂材料は耐熱性が飛躍的に向上し、屈折率分布の熱的な安定性が高く、室温以上の高温に長期間さらされた場合においても、伝送帯域の低下を防止できる。さらに、屈折率が高い化合物（Ｂ）は開口数ＮＡを大きくできる。
【０１１０】
また、化合物（Ｂ）は、重合体（Ａ）に対する溶解性が良好であるため、本発明の光学樹脂材料の透明性は良好であり、ミクロな相分離や化合物（Ｂ）の微結晶などにより生じる光散乱が少ない。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gradient index optical resin material having both high transparency and heat resistance, which has been difficult to realize with conventional optical resin materials.
The optical resin material of the present invention may itself be an optical transmission body such as an optical fiber, or may be a base material of an optical transmission body such as a preform for manufacturing an optical fiber.
[0002]
Since the optical transmission material, which is the optical resin material of the present invention, is an amorphous resin, it does not scatter light and is extremely transparent in a wide wavelength band from ultraviolet light to near infrared light. It can be used effectively in the optical system. In particular, an optical transmission body having a low loss is provided at wavelengths of 1300 nm and 1550 nm, which are wavelengths used for a trunk silica fiber in the optical communication field.
The optical transmission material, which is the optical resin material of the present invention, has heat resistance, chemical resistance, moisture resistance, and non-flammability that can withstand severe use conditions in an engine room of an automobile.
[0003]
An optical transmission material that is an optical resin material of the present invention includes a refractive index distribution type optical fiber, a rod lens, an optical waveguide, an optical splitter, an optical multiplexer, an optical demultiplexer, an optical attenuator, an optical switch, an optical isolator, It is useful as a wide variety of refractive index distribution type optical transmitters such as an optical transmitter module, an optical receiver module, a coupler, a deflector, and an optical integrated circuit.
[0004]
Here, the refractive index distribution means a region where the refractive index continuously changes along a specific direction of the optical transmission body. For example, the refractive index distribution of the refractive index distribution type optical fiber is the radial direction from the center of the fiber. The refractive index decreases in a curve close to a parabola.
When the optical resin material of the present invention is a base material of an optical transmission body, it can be spun by hot drawing or the like to produce an optical transmission body such as a gradient index optical fiber.
[0005]
[Prior art]
Conventionally, as a resin for a refractive index distribution type plastic optical transmission body, a fluorine-containing polymer having a fluorine-containing aliphatic ring structure in an amorphous main chain having no C—H bond has been known (Japanese Patent Laid-Open No. Hei 9 (1994) 8-5848). The refractive index distribution type plastic optical transmission body, which can be diffused in this resin and has a refractive index different from that of this resin, is distributed in this resin. Optical transmission of methyl methacrylate resin, carbonate resin, norbornene resin, etc. It is known to provide an optical transmission body with low loss at wavelengths of 1300 nm and 1550 nm, which could not be achieved by the body.
[0006]
However, when diffusing materials having different refractive indexes are distributed in order to form a refractive index distribution, the glass transition temperature T of the optical resin is obtained._g There is a problem that the heat resistance is lowered due to a decrease in the temperature. In particular, in an optical resin material in which a diffusing material having a refractive index not so high, such as an oligomer (refractive index: 1.41), which is a 5- to 8-mer chlorotrifluoroethylene, is dispersed, the numerical aperture NA [NA = (N² -M² )^1/2 , N is the maximum value of the refractive index in the gradient index optical resin material, and m is the minimum value of the refractive index in the gradient index optical resin material. ], It is necessary to increase the content of the diffusing substance.
[0007]
On the other hand, T of this oligomer_g Is a low temperature of about −60 ° C. and is a liquid compound at room temperature. Therefore, T increases as the content increases in order to increase NA._g Decreases. As a result, when the optical transmission body is exposed to a high temperature, the refractive index distribution changes or the optical transmission performance changes, so that it is difficult to increase the NA.
[0008]
In addition, diffusing substances such as dibromotetrafluorobenzene and chloroheptafluoronaphthalene described in JP-A-8-5848 have a high refractive index, so that the addition amount for obtaining a sufficient numerical aperture NA can be reduced. Even in dispersed optical resin materials, T_g Is low and heat resistance is not sufficient. In addition, since these diffusing materials are not very soluble in the resin, light scattering is likely to occur, causing an increase in optical transmission loss.
[0009]
[Problems to be solved by the invention]
An object of the present invention is to solve the problems of conventional refractive index distribution type optical resin materials, and to provide an optical resin material having improved heat resistance and low optical transmission loss.
[0010]
[Means for Solving the Problems]
In order to obtain a fluorine-containing optical resin material having heat resistance and low scattering loss, the present inventor has a high refractive index while maintaining solubility as a diffusing substance for forming a refractive index distribution, and T_g Therefore, it has been found that a specific fluorine-containing polycyclic compound is effective as such a compound.
[0011]
That is, the present invention is a kind in which the refractive index is higher by 0.005 or more in comparison between the amorphous fluoropolymer (A) having substantially no C—H bond and the fluoropolymer (A). The fluorine-containing polycyclic compound (B) has a concentration gradient in which the concentration of the fluorine-containing polycyclic compound (B) decreases from the center to the peripheral direction in the fluorine-containing polymer (A). 1 or more fluorine-containing polycyclic compounds (B) selected from the group consisting of the following (B1), (B2) and (B3) It is a refractive index distribution type optical resin material characterized by being a polycyclic compound.
(B1) One type in which two or more fluorine-containing rings having a carbon ring or a heterocyclic ring and having a fluorine atom or a perfluoroalkyl group are selected from the group consisting of a triazine ring, an oxygen atom, a sulfur atom, a phosphorus atom and a metal atom A fluorine-containing non-condensed polycyclic compound bonded by a bond including the above and having substantially no C—H bond.
(B2) A fluorine-containing non-condensed polycyclic compound in which three or more fluorine-containing rings having a carbon atom or a heterocyclic ring and having a fluorine atom or a perfluoroalkyl group are bonded directly or with a bond containing a carbon atom. And a compound having substantially no C—H bond.
(B3) A fluorine-containing condensed polycyclic compound which is a condensed polycyclic compound composed of three or more carbon rings or heterocyclic rings and substantially has no C—H bond.
[0012]
The fluorine-containing polycyclic compound (hereinafter referred to as compound (B)) in the present invention is a compound that substantially does not have a C—H bond (that is, a carbon-hydrogen bond) in which light absorption occurs in near infrared light. And a compound having a refractive index higher by 0.005 or more in comparison with an amorphous fluorine-containing polymer (A) (hereinafter referred to as polymer (A)) having substantially no C—H bond, which will be described later. .
[0013]
The compound (B) is one or more fluorine-containing polycyclic compounds selected from the group consisting of the above (B1), (B2) and (B3). As the compound (B), one type selected from the above group may be used alone, or two or more types selected from the above group may be used in combination.
[0014]
The compound (B) is preferably a perfluoro compound having a structure in which all hydrogen atoms in the compound are substituted with fluorine atoms or perfluoroalkyl groups. As long as the object of the present invention is not impaired, a part of fluorine atoms in the perfluoro compound may be substituted with 1 to 2 chlorine atoms or bromine atoms. The number average molecular weight of the compound (B) is 3 × 10² ~ 2x10^Three Is preferred, 3 × 10² ~ 1x10^Three Is more preferable.
From the viewpoint of increasing the solubility with the polymer (A), the compound (B) preferably has a perfluoroalkyl group, and from the viewpoint of increasing the refractive index difference from the polymer (A), the compound (B) It preferably has no perfluoroalkyl group.
[0015]
The fluorine-containing ring in the present invention is a carbocyclic or heterocyclic ring having a fluorine atom or a perfluoroalkyl group. The carbocycle and heterocycle are preferably selected from those having 4 or more members, and more preferably 4 to 6 members. The atoms constituting the heterocyclic ring are preferably selected from carbon atoms, nitrogen atoms, oxygen atoms, sulfur atoms and phosphorus atoms. As a perfluoroalkyl group, a C1-C20 perfluoroalkyl group is preferable.
[0016]
As the carbocycle, a cyclic saturated hydrocarbon ring such as a cyclopentane ring or a cyclohexane ring; an aromatic hydrocarbon ring such as a benzene ring or a ring in which one or two hydrogen atoms of the benzene ring are substituted with a methyl group; Examples thereof include cyclic unsaturated hydrocarbon rings other than aromatic hydrocarbon rings such as cyclopentene ring and cyclohexene ring.
Examples of the heterocycle include heterocycles having one heteroatom such as a thiophene ring, furan ring, pyridine ring, triazine ring and triazole ring, heterocycles having two heteroatoms such as isothiazole ring, and the like.
A preferred fluorine-containing ring is a fluorine-containing aromatic hydrocarbon ring, and a more preferred fluorine-containing ring is a perfluoroaromatic hydrocarbon ring. A benzene ring is preferred as the aromatic hydrocarbon ring.
[0017]
The fluorine-containing non-condensed polycyclic compound in the present invention is a compound in which two or three or more fluorine-containing rings are bonded without sharing two or more atoms. Binding without sharing two or more atoms means that the fluorine-containing rings are bonded by sharing one atom, or that the fluorine-containing rings are directly or indirectly bonded. The indirect bonding of a fluorine-containing ring means that the fluorine-containing ring is bonded via one or more atoms.
[0018]
When two fluorine-containing rings are bonded, the bond is a bond including at least one selected from the group consisting of a triazine ring, an oxygen atom, a sulfur atom, a phosphorus atom, and a metal atom. When three or more fluorine-containing rings are bonded, the bond is a bond containing at least one selected from the group consisting of a triazine ring, an oxygen atom, a sulfur atom, a phosphorus atom, and a metal atom; A bond or a bond containing a carbon atom.
[0019]
The metal atom is preferably a divalent to tetravalent metal atom selected from Zn, Sn, Pb, Ge, Si, Ti, Hg, Tl, As, Se, Te and Cd. Since a fluorine-containing non-condensed polycyclic compound having good thermal stability and chemical stability is provided, a more preferred metal atom is a Sn atom.
[0020]
As the fluorine-containing non-condensed polycyclic compound in which two or more fluorine-containing rings are bonded by a bond containing a triazine ring, a fluorine-containing aromatic triazine compound represented by any one of the following formulas 1 to 3 is preferable. In this specification, Φ^g (G is an integer of 1 to 6) represents a residue obtained by removing g fluorine atoms from perfluorobenzene. When a fluorine atom remains after removing g fluorine atoms, a structure in which a part or all of the fluorine atom is substituted with a perfluoroalkyl group may be used.
[0021]
As the fluorine-containing non-condensed polycyclic compound in which two or more fluorine-containing rings are bonded by a bond containing a phosphorus atom, (Φ¹ )_Three A compound represented by -P or a compound bound by a bond containing a phosphazatriene ring represented by the following formula 4 is preferred.
[0022]
The fluorine-containing non-condensed polycyclic compound in which two or more fluorine-containing rings are bonded by a bond containing a sulfur atom is preferably a fluorine-containing aromatic sulfur-containing compound represented by the following formula 5 or formula 6. However, in Formula 5, h is an integer of 1-4, and in Formula 6, k is an integer of 1-6.
[0023]
The fluorine-containing non-condensed polycyclic compound in which two or more fluorine-containing rings are bonded by a bond containing a metal atom is preferably a fluorine-containing aromatic metal-containing compound represented by the following formula 7 or formula 8. However, in Formula 7 and Formula 8, M is a metal atom selected from Zn, Sn, Pb, Ge, Si, Ti, Hg, Tl, As, Se, Te and Cd, and p and q are valences of the metal M. It is an integer of 2-4.
[0024]
As the fluorine-containing non-condensed polycyclic compound in which three or more fluorine-containing rings are bonded directly or by a bond containing carbon, a fluorine-containing aromatic compound represented by any of the following formulas 9 to 12 is preferable. . From the viewpoint of not inhibiting the transparency of the gradient index optical resin material, Φ in the fluorine-containing aromatic compound¹ ~ Φ^Four The total number of is preferably 3-5.
[0025]
[Chemical 1]

[0026]
[Chemical 2]
F-(-Φ² -S-)_h −Φ¹               Formula 5
Φ^k (-S-Φ¹ )_k                       Equation 6
(Φ¹ )_p -M Equation 7
(Φ¹ -S-)_q -M Equation 8
[0027]
[Chemical 3]

[0028]
A condensed polycyclic compound composed of three or more carbon rings or heterocyclic rings, and a fluorine-containing condensed polycyclic compound in which some or all of hydrogen atoms are substituted with fluorine atoms or fluorine-containing groups As the carbocycle and heterocyclic ring in, a 4-membered or higher ring is preferable, and a 4- to 6-membered ring is more preferable. Preferable atoms constituting the heterocyclic ring are selected from carbon atoms, nitrogen atoms, oxygen atoms, sulfur atoms, phosphorus atoms and the like.
[0029]
The fluorine-containing condensed polycyclic compound includes 3 to 4 carbon rings such as perfluorofluorene, perfluorophenalene, perfluorophenanthrene, perfluoroanthracene, perfluorotriphenylene, perfluoropyrene, perfluorochrysene, and perfluoronaphthacene. A fluorine-condensed polycyclic hydrocarbon or a fluorine-containing condensed polycyclic compound represented by the following formula 13 or formula 14 is preferred.
[0030]
[Formula 4]

[0031]
From the viewpoint of not inhibiting the transparency of the refractive index distribution type optical resin material, a fluorine-containing condensed polycyclic hydrocarbon composed of three carbon rings such as perfluorofluorene, perfluorophenalene, perfluorophenanthrene, and perfluoroanthracene is more preferable. preferable.
[0032]
The compound (B) is preferably selected from those having high thermal stability, high solubility with the polymer (A), and those that do not hinder the transparency of the gradient index optical resin material.
As such a compound (B), a fluorine-containing non-condensed polycyclic compound in which two or more fluorine-containing rings are bonded by a bond containing at least a triazine ring is particularly preferable. Examples of the triazine ring include 1,2,3-triazine ring, 1,2,4-triazine ring and 1,3,5-triazine ring, and 1,3,5-triazine ring is preferable.
[0033]
The polymer (A) in the present invention is a polymer that is non-crystalline and has substantially no C—H bond that absorbs light by near infrared light. The polymer (A) is not particularly limited as long as it is an amorphous fluorine-containing polymer having no CH bond, but a fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain is preferable.
[0034]
Having a fluorine-containing aliphatic ring structure in the main chain means that at least one carbon atom constituting the aliphatic ring is a carbon atom in the carbon chain constituting the main chain, and the carbon atom constituting the aliphatic ring is It means having a structure in which a fluorine atom or a fluorine-containing group is bonded to at least a part. As the fluorine-containing aliphatic ring structure, a fluorine-containing aliphatic ether ring structure is more preferable.
[0035]
The viscosity of the polymer (A) in the molten state is 10 at a melting temperature of 200 to 300 ° C.^Three -10^Five Poise is preferred. If the melt viscosity is too high, melt spinning is difficult, and the diffusion of the compound (B) necessary for the formation of the refractive index distribution is difficult to occur, making it difficult to form the refractive index distribution. In addition, if the melt viscosity is too low, there is a practical problem. That is, when it is used as an optical transmission body in an electronic device or an automobile, it is softened by being exposed to a high temperature, and the light transmission performance is lowered.
The number average molecular weight of the polymer (A) is 1 × 10^Four ~ 5x10⁶ Is preferred, 5 × 10^Four ~ 1x10⁶ Is more preferable. If the molecular weight is too small, heat resistance may be impaired, and if it is too large, it becomes difficult to form an optical transmission body having a refractive index distribution.
[0036]
Polymers having a fluorine-containing aliphatic ring structure include those obtained by polymerizing monomers having a fluorine-containing ring structure, and cyclization of fluorine-containing monomers having two or more polymerizable double bonds A polymer having a fluorine-containing aliphatic ring structure in the main chain obtained by polymerization is preferred.
[0037]
A polymer having a fluorinated alicyclic structure in a main chain obtained by polymerizing a monomer having a fluorinated alicyclic structure is known from JP-B 63-18964. That is, by homopolymerizing a monomer having a fluorine-containing aliphatic ring structure such as perfluoro (2,2-dimethyl-1,3-dioxole), this monomer and tetrafluoroethylene, chlorotrifluoroethylene , A polymer having a fluorine-containing aliphatic ring structure in the main chain can be obtained by copolymerizing with radical polymerizability such as perfluoro (methyl vinyl ether).
[0038]
Further, polymers having a fluorinated aliphatic ring structure in the main chain obtained by cyclopolymerization of a fluorinated monomer having two or more polymerizable double bonds are disclosed in JP-A-63-238111 and This is known from Japanese Utility Model Laid-Open No. 63-238115. That is, by cyclopolymerizing perfluoro (allyl vinyl ether), perfluoro (butenyl vinyl ether), etc., or radical polymerization of such monomers with tetrafluoroethylene, chlorotrifluoroethylene, perfluoro (methyl vinyl ether), etc. Can be copolymerized to obtain a polymer having a fluorine-containing aliphatic ring structure in the main chain.
[0039]
Further, a monomer having a fluorine-containing aliphatic ring structure such as perfluoro (2,2-dimethyl-1,3-dioxole) and two or more polymerizable properties such as perfluoro (allyl vinyl ether) and perfluoro (butenyl vinyl ether). A polymer having a fluorine-containing aliphatic ring structure in the main chain can also be obtained by copolymerizing with a fluorine-containing monomer having a double bond.
[0040]
As the polymer having a fluorinated alicyclic structure, the polymer unit having a fluorinated alicyclic structure is contained in an amount of 20 mol% or more, particularly 40 mol, based on the total polymer units of the polymer having a fluorinated alicyclic structure. % Or more is preferable from the viewpoints of transparency and mechanical properties.
[0041]
Specific examples of the polymer having a fluorine-containing aliphatic ring structure include those having a repeating unit represented by any of the following formulas 15 to 18. However, in Formula 15-18, h is an integer of 0-5, i is an integer of 0-4, j is 0 or 1, h + i + j is 1-6, s is an integer of 0-5, and t is 0-4. Integer, u is 0 or 1, s + t + u is 1-6, p, q, r are each independently an integer of 0-5, p + q + r is 1-6, R¹ ~ R⁶ Are each independently a fluorine atom, a chlorine atom, a deuterium atom (D) or a trifluoromethyl group.
In addition, in order to raise a refractive index, the fluorine atom in the polymer which has these fluorine-containing aliphatic ring structures may be partially substituted by the chlorine atom.
[0042]
[Chemical formula 5]

[0043]
As the monomer having a fluorine-containing aliphatic ring structure, a monomer selected from compounds represented by any one of the following formulas 19 to 21 is preferable. However, in Formulas 19-21, R⁷ ~ R¹⁸Are each independently a fluorine atom, a chlorine atom, a deuterium atom or a trifluoromethyl group, or R⁹ And R^Ten, R¹³And R¹⁴And R¹⁷And R¹⁸Are jointly-(CF₂ )_Four -,-(CF₂ )_Three -,-(CF₂ )₂ -, -CF₂ -O-CF₂ -,-(CF₂ )₂ -O-CF₂ -, -O- (CF₂ )₂ -And -O- (CF₂ )_Three A divalent group selected from the group consisting of-may be formed.
[0044]
[Chemical 6]

[0045]
Specific examples of the compound represented by any one of formulas 19 to 21 include compounds represented by any of the following formulas 22 to 29.
[0046]
[Chemical 7]

[0047]
As the fluorine-containing monomer having two or more polymerizable double bonds, a compound represented by any of the following formulas 30 to 32 is preferable. However, in formulas 30 to 32, Y¹ ~ Y^Ten, Z¹ ~ Z⁸ And W¹ ~ W⁸ Are each independently a fluorine atom, a chlorine atom, a deuterium atom or a trifluoromethyl group.
[0048]
[Chemical 8]
CY¹ Y² = CY^Three OCY^Four Y^Five CY⁶ Y⁷ CY⁸ = CY⁹ Y^Ten        Equation 30
CZ¹ Z² = CZ^Three OCZ^Four Z^Five CZ⁶ = CZ⁷ Z⁸                   Formula 31
CW¹ W² = CW^Three OCW^Four W^Five OCW⁶ = CW⁷ W⁸                 Equation 32
[0049]
Specific examples of the compound represented by any one of Formulas 30 to 32 include the following compounds.
CF₂ = CFOCF₂ CF₂ CF = CF₂
CF₂ = CFOCCl₂ CF₂ CF = CF₂
CF₂ = CFOCF₂ CF₂ CCl = CF₂
CF₂ = CFOCF₂ CFClCF = CF₂
CF₂ = CFOCF₂ CF₂ CF = CFCl
CF₂ = CFOCF₂ CF (CF_Three ) CF = CF₂
CF₂ = CFOCF₂ CF (CF_Three ) CCl = CF₂
CF₂ = CFOCF₂ CF = CF₂
CF₂ = CFOCF (CF_Three ) CF = CF₂
CF₂ = CFOC (CF_Three )₂ CF = CF₂
CF₂ = CFOCF₂ OCF = CF₂
CF₂ = CClOCF₂ OCCl = CF₂
CF₂ = CFOCCl₂ OCF = CF₂
CF₂ = CFOC (CF_Three )₂ OCF = CF₂
[0050]
In producing the optical resin material of the present invention, the molding of the resin and the formation of the refractive index distribution may be performed simultaneously or separately. For example, the optical resin material of the present invention can be produced by forming a refractive index at the same time as molding a resin by spinning or extrusion molding. Further, the refractive index distribution can be formed after the resin is molded by spinning or extrusion molding. Furthermore, an optical resin material such as an optical fiber can be manufactured by manufacturing a preform (base material) having a refractive index distribution and molding (for example, spinning) the preform. As described above, the optical resin material of the present invention also means a preform having the above refractive index distribution.
[0051]
The optical resin material of the present invention is most preferably a gradient index optical fiber. In this optical fiber, since the compound (B) is a substance having a higher refractive index than that of the polymer (A), the compound (B) has a concentration gradient in which the concentration decreases from the center of the optical fiber along the peripheral direction. Distributed. Thereby, it becomes a refractive index distribution from which a refractive index falls along the peripheral direction from the center of an optical fiber. The concentration distribution of the compound (B) can be usually formed by disposing the compound (B) in the center of the molten polymer (A) and diffusing the compound (B) in the peripheral direction.
[0052]
Since the compound (B) has a refractive index higher by 0.005 or more than the polymer (A), the difference in refractive index between the maximum value n and the minimum value m in the optical resin material can be increased. That is, “(n² -M² )^1/2 Can be set to 0.20 or more. The compound (B) preferably has a refractive index higher by 0.01 or more in comparison with the polymer (A). The refractive index of the compound (B) is preferably 1.45 or more, more preferably 1.47 or more.
[0053]
In general, when a low molecular weight compound is added to a polymer, the T_g Decreases. When a compound having a refractive index that is not so large is used as a material for forming a refractive index difference, the content in the polymer must be increased._g Decreases and heat resistance decreases.
[0054]
Since the compound (B) in the present invention has a high refractive index, a small amount of addition, for example, even when the concentration of the compound (B) in the central part of the optical resin material is 15% by weight or less, the desired refractive index difference is obtained. Can be formed, T_g There is an advantage that there is little decrease in.
In addition, T of compound (B)_g Is high, so T in the center of the optical resin material_g Can be set to 70 ° C. or higher. Depending on the type of compound (B), T at the center of the optical resin material_g May be 90 ° C. or higher. Thereby, the heat resistance of the optical resin material of the present invention is dramatically improved.
[0055]
Moreover, the compound (B) has good solubility in the polymer (A), and its saturated solubility is 5 to 20% by weight. The solubility parameter (SP value), which is a measure of solubility, is 6 to 7 (cal / cm) for the polymer (A).^Three )^1/2 Whereas the compound (B) is 8 to 10 (cal / cm^Three )^1/2 Therefore, the solubility is considered good.
When the content of the compound (B) with respect to the polymer (A) is less than or equal to the saturated solubility, the optical resin material of the present invention has good transparency, such as micro phase separation and fine crystals of the compound (B). Less light scattering.
[0056]
The optical transmission material which is the optical resin material of the present invention can have a wavelength of 700 to 1600 nm and a transmission loss of 100 m of 15 db or less. Such a low level of transmission loss is very advantageous at relatively long wavelengths of 700-1600 nm.
That is, by using the same wavelength as the quartz optical fiber, it is easy to connect to the quartz optical fiber, and the light source is less expensive than the conventional plastic optical fiber that has to use a wavelength shorter than 700 to 1600 nm. There are benefits.
[0057]
In the transmission characteristics of the optical transmission body, there is a transmission band as an important characteristic along with the transmission loss. In order to transmit a large amount of information at high speed, a wide transmission band is desired. At present, the silica-based single mode fiber used in long-distance communication has a wide transmission band of several tens of GHz · km.
[0058]
On the other hand, the plastic optical fiber has a large fiber diameter, and since it is easy to connect to a light source / light receiving element or to connect fibers, there is an increasing expectation for the construction of an inexpensive short-range communication system.
[0059]
A normal plastic optical fiber is a step index type, and its transmission band is as narrow as several MHz · km. In order to solve this problem, a gradient index plastic optical fiber having a wider transmission band as in the present invention has been proposed. In this refractive index distribution type plastic optical fiber, if this refractive index distribution is not thermally stable, the transmission band is lowered as a result.
[0060]
Since the optical resin material of the present invention has drastically improved heat resistance, the thermal stability of the refractive index distribution is high, and even when exposed to high temperatures above room temperature for a long time, the transmission band is reduced. Can be prevented.
[0061]
【Example】
EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these. In the following examples, Examples 1 to 3 are synthesis examples of the polymer (A), Examples 4 to 10 and Examples 16 to 17 are examples, and Examples 11 to 15 are comparative examples.
[0062]
"Example 1"
750 g perfluoro (butenyl vinyl ether) [PBVE], 4 kg ion-exchanged water, 260 g methanol and 3.7 g ((CH_Three )₂ CHOCOO)₂ Was placed in a glass flask having an internal volume of 5 L. After the system was replaced with nitrogen, suspension polymerization was performed at 40 ° C. for 22 hours, and the number average molecular weight was about 5 × 10.^Four 690 g of this polymer was obtained. By treating this polymer in a fluorine / nitrogen mixed gas (fluorine gas concentration: 20% by volume) atmosphere at 250 ° C. for 5 hours, a polymer having good light transmission and thermal stability (hereinafter referred to as polymer A1) is obtained. Obtained.
[0063]
The intrinsic viscosity [η] of the polymer A1 was 0.3 at 30 ° C. in perfluoro (2-butyltetrahydrofuran) [PBTHF]. T of polymer A1_g Was 108 ° C. and was a tough and transparent glassy polymer at room temperature. The refractive index is 1.342 and the SP value is 6.6 (cal / cm^Three )^1/2 Met.
[0064]
"Example 2"
173 g PBVE, 27 g perfluoro (2,2-dimethyl-1,3-dioxole) [PDD], 200 g PBTHF and 2 g ((CH_Three )₂ CHOCOO)₂ Was placed in a stainless steel autoclave having an internal volume of 1 L. After replacing the system with nitrogen, polymerization was carried out at 40 ° C. for 20 hours, and the number average molecular weight was about 1.5 × 10^Five 20 g of a transparent polymer was obtained. By treating this polymer in a fluorine / nitrogen mixed gas (fluorine gas concentration: 20% by volume) atmosphere at 250 ° C. for 5 hours, a polymer having good light transmission and thermal stability (hereinafter referred to as polymer A2) is obtained. Obtained. T of polymer A2_g Is 150 ° C., refractive index is 1.325, SP value is 6.5 (cal / cm^Three )^1/2 Met.
[0065]
"Example 3"
Radical polymerization of PDD and tetrafluoroethylene at a weight ratio of 80:20 using PBTHF as a solvent, and T_g Has a number average molecular weight of about 1.7 × 10 at 160 ° C.^Five The polymer was obtained. By treating this polymer in a fluorine / nitrogen mixed gas (fluorine gas concentration: 20% by volume) atmosphere at 250 ° C. for 5 hours, a polymer having good light transmission and thermal stability (hereinafter referred to as polymer A3) is obtained. Obtained. The polymer A3 is colorless and transparent, the refractive index is 1.305, and the SP value is 6.3 (cal / cm^Three )^1/2 Met.
[0066]
"Example 4"
A mixture of polymer A1 and perfluoro (tetraphenyltin) [7% by weight of the latter in the mixture] is charged into a glass sealed tube and melt molded at 250 ° C. to form a cylindrical molded body (hereinafter referred to as molded body a). Got. The refractive index of the molded body a is 1.357, T_g Was 91 ° C.
[0067]
Next, a cylindrical tube composed only of the polymer A1 was prepared by melt molding, and a molded body a was inserted into the hollow part of the cylindrical tube and heated to 200 ° C. to be combined to obtain a preform. By melt spinning the preform at 230 ° C., an optical fiber having a refractive index that gradually decreases from the central portion toward the peripheral portion was obtained. The optical transmission characteristic of the obtained optical fiber is 200 dB / km at 780 nm, 150 dB / km at 850 nm, 120 dB / km at 1300 nm, and is an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0068]
After this optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, the refractive index distribution was measured by an interfaco interference microscope, and no change was observed when compared with the refractive index distribution before storage. Furthermore, the transmission characteristics were evaluated by measuring the transmission band by the following pulse method.
[0069]
That is, pulsed laser light was oscillated using a pulse generator, incident on an optical fiber, and emitted light was detected with a sampling oscilloscope. The transmission band was measured by Fourier-transforming this detection signal and analyzing the frequency characteristics. When the transmission band was measured after storing the optical fiber at 70 ° C. for 1000 hours, it was confirmed that heat resistance was good because the band was not reduced at 260 MHz · km before and after storage.
[0070]
"Example 5"
A mixture of polymer A1 and perfluoro (triphenylphosphine) [containing the latter at 7 wt% in the mixture] is charged into a glass sealed tube and melt-molded at 250 ° C. (hereinafter referred to as a molded product b). Got. The refractive index of the molded body b is 1.357, T_g Was 88 ° C.
[0071]
Next, a cylindrical tube made only of the polymer A1 was prepared by melt molding, and a molded body b was inserted into the hollow portion and heated to 200 ° C. to be combined to obtain a preform. By melt spinning the preform at 230 ° C., an optical fiber having a refractive index that gradually decreases from the central portion toward the peripheral portion was obtained. The optical transmission characteristic of the obtained optical fiber is 200 dB / km at 780 nm, 150 dB / km at 850 nm, 120 dB / km at 1300 nm, and is an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0072]
After this optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, the refractive index distribution was measured by an interfaco interference microscope and compared with the refractive index distribution before storage, no particular change was observed. Further, when the transmission band was measured by the same pulse method as in Example 4 and the characteristics before and after storage were compared, it was confirmed that the heat resistance was good because the band did not decrease at 240 dB · km.
[0073]
"Example 6"
A mixture of polymer A1 and 1,4-bis (perfluorophenylthio) tetrafluorobenzene (containing the latter in an amount of 5% by weight in the mixture) was charged into a glass sealed tube and melt-molded at 250 ° C. to form a cylindrical molded body ( Hereinafter, the molded product c) was obtained. The refractive index of the molded body c is 1.357, T_g Was 85 ° C.
[0074]
Next, a cylindrical tube made only of the polymer A1 was prepared by melt molding, and a molded body c was inserted into the hollow part and heated to 200 ° C. to be combined to obtain a preform. By melt spinning the preform at 230 ° C., an optical fiber having a refractive index that gradually decreases from the central portion toward the peripheral portion was obtained. The optical transmission characteristic of the obtained optical fiber is 200 dB / km at 780 nm, 150 dB / km at 850 nm, 120 dB / km at 1300 nm, and is an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0075]
After this optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, the refractive index distribution was measured by an interfaco interference microscope and compared with the refractive index distribution before storage, no particular change was observed. Further, when the transmission band was measured by the same pulse method as in Example 4 and the characteristics before and after storage were compared, it was confirmed that the heat resistance was good because the band did not decrease at 250 dB · km.
[0076]
"Example 7"
A mixture of polymer A1 and perfluoro (2,4,6-triphenyl-1,3,5-triazine) [the latter is contained in 5% by weight in the mixture] is charged into a glass sealed tube and melt-molded at 250 ° C. A cylindrical shaped body (hereinafter referred to as a shaped body d) was obtained. The refractive index of the molded body d is 1.357, T_g Was 95 ° C.
[0077]
Next, a cylindrical tube composed only of the polymer A1 was prepared by melt molding, and a molded body d was inserted into the hollow portion and heated to 200 ° C. to be combined to obtain a preform. By melt spinning this preform at 240 ° C., an optical fiber having a refractive index that gradually decreases from the central portion toward the peripheral portion was obtained. The optical transmission characteristics of the obtained optical fiber are 120 dB / km at 780 nm, 100 dB / km at 850 nm, 80 dB / km at 1300 nm, and an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0078]
After this optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, the refractive index distribution was measured by an interfaco interference microscope and compared with the refractive index distribution before storage, no particular change was observed. Further, when the transmission band was measured by the same pulse method as in Example 4 and the characteristics before and after storage were compared, it was confirmed that the heat resistance was good because the band did not decrease at 300 dB · km.
[0079]
"Example 8"
A mixture of polymer A1 and perfluoroterphenyl [containing the latter at 5% by weight in the mixture] was charged into a glass sealed tube and melt-molded at 250 ° C. to obtain a cylindrical molded body (hereinafter referred to as molded body e). . The refractive index of the molded body e is 1.357, T_g Was 95 ° C.
[0080]
Next, a cylindrical tube made only of the polymer A1 was prepared by melt molding, and a molded body e was inserted into the hollow part and heated to 200 ° C. to be combined to obtain a preform. By melt spinning the preform at 230 ° C., an optical fiber having a refractive index that gradually decreases from the central portion toward the peripheral portion was obtained. The optical transmission characteristic of the obtained optical fiber is 170 dB / km at 780 nm, 140 dB / km at 850 nm, 110 dB / km at 1300 nm, and is an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0081]
After this optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, the refractive index distribution was measured by an interfaco interference microscope and compared with the refractive index distribution before storage, no particular change was observed. Further, when the transmission band was measured by the same pulse method as in Example 4 and the characteristics before and after storage were compared, it was confirmed that the heat resistance was good because the band did not decrease at 260 dB · km.
[0082]
"Example 9"
A mixture of polymer A1 and perfluoroquaterphenyl [containing the latter at 5% by weight in the mixture] is charged into a glass sealed tube and melt-molded at 250 ° C. to obtain a cylindrical molded body (hereinafter referred to as molded body f). It was. The refractive index of the molded body f is 1.357, T_g Was 93 ° C.
[0083]
Next, a cylindrical tube made only of the polymer A1 was prepared by melt molding, and the molded body f was inserted into the hollow part and heated to 200 ° C. to be combined to obtain a preform. By melt spinning this preform at 240 ° C., an optical fiber having a refractive index that gradually decreases from the central portion toward the peripheral portion was obtained. The optical transmission characteristic of the obtained optical fiber is 190 dB / km at 780 nm, 150 dB / km at 850 nm, 120 dB / km at 1300 nm, and is an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0084]
After this optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, the refractive index distribution was measured by an interfaco interference microscope and compared with the refractive index distribution before storage, no particular change was observed. Further, when the transmission band was measured by the same pulse method as in Example 4 and the characteristics before and after storage were compared, it was confirmed that the heat resistance was good because no band decrease occurred at 280 dB · km.
[0085]
"Example 10"
A mixture of the polymer A1 and perfluoroanthracene [containing the latter at 5% by weight in the mixture] was charged into a glass sealed tube and melt-molded at 250 ° C. to obtain a cylindrical molded body (hereinafter referred to as molded body g). The refractive index of the molded body g is 1.357, T_g Was 95 ° C.
[0086]
Next, a cylindrical tube made only of the polymer A1 was prepared by melt molding, and a molded body g was inserted into the hollow part and heated to 200 ° C. to be combined to obtain a preform. By melt spinning this preform at 240 ° C., an optical fiber having a refractive index that gradually decreases from the central portion toward the peripheral portion was obtained. The optical transmission characteristic of the obtained optical fiber is 190 dB / km at 780 nm, 150 dB / km at 850 nm, 120 dB / km at 1300 nm, and is an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0087]
After this optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, the refractive index distribution was measured by an interfaco interference microscope and compared with the refractive index distribution before storage, no particular change was observed. Further, when the transmission band was measured by the same pulse method as in Example 4 and the characteristics before and after storage were compared, it was confirmed that the heat resistance was good because the band did not decrease at 310 dB · km.
[0088]
"Example 11"
A mixture of a polymer A1 and a chlorotrifluoroethylene oligomer (average molecular weight 850, refractive index 1.41) [the latter is contained in a 15% by weight in the mixture] is charged into a glass sealed tube and melt-molded at 250 ° C. A molded body (hereinafter referred to as a molded body h) was obtained. The refractive index of the molded body h is 1.357, T_g Was 75 ° C.
[0089]
Next, a cylindrical tube made only of the polymer A1 was prepared by melt molding, and a molded body h was inserted into the hollow part and heated to 200 ° C. to be combined to obtain a preform. By performing melt spinning of this preform at 230 ° C., a refractive index distribution type optical fiber in which the refractive index gradually decreased from the central portion toward the peripheral portion was obtained. The optical transmission characteristics of the obtained optical fiber are 110 dB / km at 780 nm, 100 dB / km at 850 nm, 80 dB / km at 1300 nm, and an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0090]
The optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, and then the refractive index distribution was measured with an interference microscope. When compared with the refractive index distribution before storage, the refractive index decreased near the center of the core. It was. Along with this, the transmission band was reduced, and what was 260 MHz · km before storage was reduced to 160 MHz · km after storage.
[0091]
"Example 12"
A mixture of polymer A1 and Aldrich perfluorobiphenyl (refractive index of 1.45) [7% by weight of the latter contained in the mixture] was charged into a glass sealed tube and melt-molded at 250 ° C. to form a cylindrical molded body (hereinafter referred to as “the molded body”). , Referred to as a molded product i). The refractive index of the molded body i is 1.357, T_g Was 73 ° C.
[0092]
Next, a cylindrical tube made only of the polymer A1 was prepared by melt molding, and a molded body i was inserted into the hollow portion and heated to 200 ° C. to be combined to obtain a preform. By performing melt spinning of this preform at 230 ° C., a refractive index distribution type optical fiber in which the refractive index gradually decreased from the central portion toward the peripheral portion was obtained. The optical transmission characteristic of the obtained optical fiber is 150 dB / km at 780 nm, 120 dB / km at 850 nm, 100 dB / km at 1300 nm, and is an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0093]
The optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, and then the refractive index distribution was measured with an interference microscope. When compared with the refractive index distribution before storage, the refractive index decreased near the center of the core. It was. Along with this, the transmission band was reduced, and what was 200 MHz · km before storage was reduced to 110 MHz · km after storage.
[0094]
"Example 13"
A mixture of polymer A1 and perfluoro (diphenyl sulfide) manufactured by Aldrich (containing the latter at 6% by weight in the mixture) was charged into a glass sealed tube and melt-molded at 250 ° C. to form a cylindrical molded body (hereinafter referred to as molded body j). I got). The refractive index of the molded body j is 1.357, T_g Was 77 ° C.
[0095]
Next, a cylindrical tube composed only of the polymer A1 was prepared by melt molding, and a molded body j was inserted into this hollow portion and heated to 200 ° C. to be combined to obtain a preform. By performing melt spinning of this preform at 230 ° C., a refractive index distribution type optical fiber in which the refractive index gradually decreased from the central portion toward the peripheral portion was obtained. The optical transmission characteristic of the obtained optical fiber is 190 dB / km at 780 nm, 150 dB / km at 850 nm, 120 dB / km at 1300 nm, and is an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0096]
The optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, and then the refractive index distribution was measured with an interference microscope. When compared with the refractive index distribution before storage, the refractive index decreased near the center of the core. It was. Along with this, the transmission band was reduced, and what was 260 MHz · km before storage was reduced to 180 MHz · km after storage.
[0097]
"Example 14"
A mixture of the polymer A1 and perfluoronaphthalene (refractive index: 1.48) manufactured by Aldrich, Inc. [containing the latter at 6% by weight in the mixture] was charged into a glass sealed tube and melt-molded at 250 ° C. to form a cylindrical molded body (hereinafter referred to as “the molded body”). , Referred to as a molded product k). The refractive index of the molded body k is 1.357, T_g Was 76 ° C.
[0098]
Next, a cylindrical tube made only of the polymer A1 was prepared by melt molding, and a molded body k was inserted into the hollow portion and heated to 200 ° C. to be combined to obtain a preform. By performing melt spinning of this preform at 230 ° C., a refractive index distribution type optical fiber in which the refractive index gradually decreased from the central portion toward the peripheral portion was obtained. The optical transmission characteristics of the obtained optical fiber are 180 dB / km at 780 nm, 150 dB / km at 850 nm, 110 dB / km at 1300 nm, and an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0099]
The optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, and then the refractive index distribution was measured with an interference microscope. When compared with the refractive index distribution before storage, the refractive index decreased near the center of the core. It was. Along with this, the transmission band was reduced, and what was 220 MHz · km before storage was reduced to 110 MHz · km after storage.
[0100]
"Example 15"
A mixture of the polymer A1 and 1,3,5-trichloro-2,4,6-trifluorobenzene produced by PCR (containing the latter at 6% by weight in the mixture) was charged into a glass sealed tube and melt-molded at 250 ° C. A cylindrical molded body (hereinafter referred to as a molded body m) was obtained. The refractive index of the molded body m is 1.355, T_g Was 79 ° C.
[0101]
Next, a cylindrical tube made only of the polymer A1 was prepared by melt molding, and a molded body m was inserted into the hollow portion and heated to 200 ° C. to be combined to obtain a preform. By performing melt spinning of this preform at 230 ° C., a refractive index distribution type optical fiber in which the refractive index gradually decreased from the central portion toward the peripheral portion was obtained. The optical transmission characteristics of the obtained optical fiber are 210 dB / km at 780 nm, 170 dB / km at 850 nm, 130 dB / km at 1300 nm, and an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0102]
The optical fiber was stored in an oven at 70 ° C. for 1000 hours and then taken out, and then the refractive index distribution was measured with an interference microscope. When compared with the refractive index distribution before storage, the refractive index decreased near the center of the core. It was. Along with this, the transmission band was reduced, and what was 250 MHz · km before storage was reduced to 170 MHz · km after storage.
[0103]
"Example 16"
A mixture of polymer A2 and perfluoro (2,4,6-triphenyl-1,3,5-triazine) [the latter is contained in 5% by weight in the mixture] is charged into a glass sealed tube and melt-molded at 250 ° C. A columnar shaped body (hereinafter referred to as a shaped body n) was obtained. The refractive index of the molded body n is 1.340, T_g Was 130 ° C.
[0104]
Next, a cylindrical tube made only of the polymer A2 was prepared by melt molding, and a molded body n was inserted into the hollow part and heated to 230 ° C. to be combined to obtain a preform. By melt spinning the preform at 270 ° C., an optical fiber having a refractive index that gradually decreases from the central portion toward the peripheral portion was obtained. The optical transmission characteristics of the obtained optical fiber are 250 dB / km at 780 nm, 200 dB / km at 850 nm, and 170 dB / km at 1300 nm, and are optical fibers that can transmit light from visible light to near infrared light well. I confirmed that.
[0105]
After this optical fiber was stored in an oven at 85 ° C. for 1000 hours and then taken out, the refractive index distribution was measured by an interfaco interference microscope and compared with the refractive index distribution before storage, no particular change was observed. Further, when the transmission band was measured by the same pulse method as in Example 4 and the characteristics before and after storage were compared, it was confirmed that the heat resistance was good because no band decrease occurred at 280 dB · km.
[0106]
"Example 17"
A mixture of polymer A3 and perfluoro (2,4,6-triphenyl-1,3,5-triazine) [the latter is contained in 5% by weight in the mixture] is charged into a glass sealed tube and melt-molded at 250 ° C. A columnar shaped body (hereinafter referred to as a shaped body p) was obtained. The refractive index of the molded body p is 1.320, T_g Was 140 ° C.
[0107]
Next, a cylindrical tube made only of the polymer A3 was prepared by melt molding, and the molded body p was inserted into the hollow portion and heated to 230 ° C. to be combined to obtain a preform. By melt spinning the preform at 270 ° C., an optical fiber having a refractive index that gradually decreases from the central portion toward the peripheral portion was obtained. The optical transmission characteristic of the obtained optical fiber is 300 dB / km at 780 nm, 250 dB / km at 850 nm, 200 dB / km at 1300 nm, and is an optical fiber that can transmit light from visible light to near infrared light well. I confirmed that.
[0108]
After this optical fiber was stored in an oven at 85 ° C. for 1000 hours and then taken out, the refractive index distribution was measured by an interfaco interference microscope and compared with the refractive index distribution before storage, no particular change was observed. Further, when the transmission band was measured by the same pulse method as in Example 4 and the characteristics before and after storage were compared, it was confirmed that the heat resistance was good because the band did not decrease at 260 dB · km.
[0109]
【The invention's effect】
Since the compound (B) in the present invention has a high refractive index, the target refractive index difference can be formed even when added in a small amount._g There is an advantage that there is little decrease in. This advantage and the T of compound (B)_g As a result, the heat resistance of the optical resin material of the present invention is greatly improved, the thermal stability of the refractive index distribution is high, and even when exposed to high temperatures above room temperature for a long time, Decrease can be prevented. Further, the compound (B) having a high refractive index can increase the numerical aperture NA.
[0110]
Further, since the compound (B) has good solubility in the polymer (A), the transparency of the optical resin material of the present invention is good, and microscopic phase separation or microcrystals of the compound (B) are used. Less light scattering occurs.

Claims (7)

One or more fluorine-containing polycycles having a refractive index higher by 0.005 or more in comparison between the amorphous fluorine-containing polymer (A) having substantially no CH bond and the fluorine-containing polymer (A) Refraction that consists of the formula compound (B), and the fluorine-containing polycyclic compound (B) is distributed in the fluorine-containing polymer (A) with a concentration gradient that decreases from the center along the peripheral direction. A rate distribution type optical resin material, wherein the fluorine-containing polycyclic compound (B) is at least one fluorine-containing polycyclic compound selected from the group consisting of the following (B1), (B2) and (B3): A refractive index distribution type optical resin material.
(B1) One kind selected from the group consisting of a triazine ring, an oxygen atom, a sulfur atom, a phosphorus atom and a metal atom, in which two or more fluorine-containing rings having a carbon ring or a heterocyclic ring and having a fluorine atom or a perfluoroalkyl group A fluorine-containing non-condensed polycyclic compound bonded by a bond including the above and having substantially no CH bond.
(B2) A fluorine-containing non-condensed polycyclic compound in which three or more fluorine-containing rings having a carbon atom or a heterocyclic ring and having a fluorine atom or a perfluoroalkyl group are bonded directly or with a bond containing a carbon atom. And a compound having substantially no C—H bond.
(B3) A fluorine-containing condensed polycyclic compound which is a condensed polycyclic compound composed of three or more carbon rings or heterocyclic rings and substantially has no CH bond. The numerical aperture NA [NA = (n ² −m ² ) ^1/2 in the gradient index optical resin material according to claim ¹ , n is the maximum value of the refractive index in the gradient index optical resin material, and m is Minimum refractive index in the gradient index optical resin material. ] Is a refractive index distribution type optical resin material of 0.20 or more. A refractive index distribution type optical resin material having a glass transition temperature of 70 ° C. or more at the center of the gradient index optical resin material according to claim 1. A refractive index distribution type optical resin material, wherein the concentration of the fluorine-containing polycyclic compound (B) at the center of the refractive index distribution type optical resin material according to claim 1, 2, or 3 is 15% by weight or less. The refractive index distribution type optical resin material according to any one of claims 1 to 4, wherein the refractive index of the fluorine-containing polycyclic compound (B) is 1.45 or more. The refractive index distribution type optical resin material according to any one of claims 1 to 5, wherein the fluoropolymer (A) is a fluoropolymer having a fluorinated aliphatic ring structure in the main chain. 7. The refractive index distribution type optical resin material according to claim 1, wherein the optical resin material is a preform for manufacturing a refractive index distribution type optical fiber or a refractive index distribution type optical fiber.