JP4175174B2 - Composite material and manufacturing method thereof - Google Patents

Description

【００１７】
（ここで、Ｒ¹，Ｒ²は炭素数が１〜３のアルキル基（ｎ＝１〜３）、Ｒ³は結合そのもの又は炭素数が１〜２０の脂肪族基を表す。Ｒ⁴，Ｒ⁵，Ｒ⁶は同一であっても異なっていても良く、それぞれ、水素又は炭素数１〜２０の脂肪族基を表す）。
【００１８】
【発明の実施の形態】
本発明で用いられるチタンを含む金属としては、純チタンまたはチタン合金を使用することができる。ここで、チタン合金は、いわゆるα合金、β合金、および両層を有するα＋β合金系のいずれを使用する事もできる。なかでも、通常の使用温度時に、高強度が得られやすいβ合金のＴｉ−１５Ｖ−３Ｃｒ−３Ａｌ−３Ｓｎ合金やα＋β合金のＴｉ−６Ａｌ−４Ｖ合金が好ましく使用される。
【００１９】
チタンを含む金属の形状は特に限定されず、板状、棒状、糸状いずれの形態で有っても構わないが、。板状物は接着面積が広いため、接着性向上の効果が顕著に発現されるため好ましく使用される。
【００２０】
本発明は、チタンを含む金属、特定のイミダゾールシランを含む化合物、非繊維強化プラスチック、繊維強化プラスチックがこの順に形成されたコンポジット材料であるが、各構成成分を形成するプロセスは公知のプロセスを使用することができる。例えば、チタンを含む金属表面にイミダゾールシランを含む化合物を塗布、乾燥後、非繊維強化プラスチックを挟み込むように繊維強化プラスチックを重ね合わせ成形する方法等が好ましく使用される。
【００２１】
本発明において、チタンを含む金属表面の少なくとも一部に、下記化学式で表されるイミダゾールシランを含む化合物が存在する必要がある。
【００２２】
【化３】

【００２３】
（ここで、Ｒ¹，Ｒ²は炭素数が１〜３のアルキル基（ｎ＝１〜３）、Ｒ³は結合そのもの又は炭素数が１〜２０の脂肪族基を表す。Ｒ⁴，Ｒ⁵，Ｒ⁶は同一であっても異なっていても良く、それぞれ、水素又は炭素数が１〜２０の脂肪族基を有す）。
【００２４】
上記化学式で表されるイミダゾールシランの具体例としては、下記化学式群を挙げることができる。
【００２５】
【化４】

【００２６】
【化５】

【００２７】
【化６】

【００２８】
（ここで、上記した３つの化学式群において、Ｒ¹は水素または炭素数が１〜２０のアルキル基である。Ｒ²は水素、ビニル基又は炭素数が１〜５のアルキル基である。Ｒ³、Ｒ⁴は炭素数が１〜３のアルキル基である。ｎは１〜３から選ばれる整数である）。
【００２９】
本発明に使用するイミダゾールシランを含む化合物としては、イミダゾールシラン１００％から成るものであっても良く、また、ハンドリング性の改良等の目的で、その他の成分、例えば、可塑剤等を含んでいても良い。
【００３０】
チタンを含む金属の表面にイミダゾールシランを含む化合物を形成させる方法としては特に限定されないが、例えば、イミダゾールシランを、水またはエタノール、メタノールなどの溶媒に０．１〜１０％の濃度で希釈し、該希釈溶液を金属表面に塗布もしくはディッピングなどにより付与する方法等が好ましく用いられる。また、該希釈溶液をスプレイアップするなども用いることができる。ここで、溶液には、塗布性等の改良のため、イミダゾールシラン以外の成分を添加することもできる。
【００３１】
溶液を塗布した後は、常温放置もしくは加温や減圧処理により、水またはエタノール、メタノールなどの溶媒の一部または全部を揮発させることが好ましい。
【００３２】
本発明において、前記化学式で表されるイミダゾールシランと繊維強化プラスチックの間に、非繊維強化プラスチックが形成される。この非繊維強化プラスチックからなる境界層が応力緩衝材として作用することにより、コンポジット材料に荷重や衝撃が負荷されたときに、応力緩和層として作用することにより、チタンを含む金属と繊維強化プラスチックとの剥離を防止する事ができる。
【００３３】
非繊維強化プラスチックの形成形状は特に限定されないが、好ましくは層状である。該層の厚さは、応力緩和性と軽量化とのバランスから、０．０１ｍｍ〜０．１ｍｍの範囲内であることが好ましく、より好ましくは０．０１５ｍｍ〜０．０５ｍｍの範囲内、最も好ましくは０．０１５ｍｍ〜０．０２５ｍｍの範囲である。非繊維強化プラスチックからなる境界層が０．０１ｍｍよりも薄いと、応力緩和性が小さくなり、剥離の可能性が増え、逆に、０．１ｍｍより厚すぎると重量増加の問題が生じる可能性がある。
【００３４】
非繊維強化プラスチックとして使用されるプラスチック素材は特に限定されず、公知の熱可塑性樹脂、熱硬化性樹脂等を使用することができる。好ましくは熱硬化性樹脂であり、さらに好ましくはエポキシ樹脂である。
【００３５】
非繊維強化プラスチックとしては、チタンを含む金属と繊維強化プラスチックの接着性の観点から、繊維強化プラスチックに用いる素材と同一又は類似素材であることが好ましい。
【００３６】
非繊維強化プラスチックとしてエポキシ樹脂を使用した場合、コンポジット材料を強化したり靱性を付与する目的等のために、熱可塑性プラスチックや熱可塑性エラストマーを非繊維強化プラスチック中に含有させることも好ましい態様である。
【００３７】
ここで、熱可塑性プラスチックとしては、ポリイミド（ＰＩ）、ポリエーテルイミド（ＰＥＩ）、ポリアミド（ＰＡ）、ポリアミドイミド（ＰＡＩ）、ポリエーテルスルホン（ＰＥＳ）、ポリエーテルエーテルスルホン（ＰＥＥＳ）などが好ましく使用される。
【００３８】
また、熱可塑性エラストマーとしては、アイオノマー（ＩＯ）、ポリオレフィン系（ＴＰＯ）、ウレタン系（ＴＰＵ）、ポリアミド系（ＴＰＡＥ）、ポリ塩化ビニル系（ＴＰＶＣ）系などが好ましく使用される。
【００３９】
これら熱可塑性樹脂、熱可塑性エラストマーは、粒子状または不織布形態で使用するのが好ましい態様である。
【００４０】
本発明において、繊維強化プラスチックとは、連続又は不連続強化繊維で強化された熱可塑性樹脂または熱硬化性プラスチック複合材料の総称である。繊維強化プラスチックの平均繊維体積含有率は特に限定されないが、２０〜７５％の範囲内が好ましく、４５〜６５％の範囲内であることがより好ましい。
【００４１】
繊維強化プラスチックに使用する繊維の種類は特に限定されず、例えば、炭素繊維、ガラス繊維などの無機繊維あるいはケブラー繊維、ポリエチレン繊維、ポリアミド繊維、アラミド繊維などの有機繊維が挙げられる。軽量性、力学特性から、炭素繊維が好ましく使用される。
【００４２】
繊維強化プラスチックに使用されるプラスチックは特に限定されず、例えば、エポキシ樹脂、ポリエステル樹脂、ビニルエステル樹脂、フェノール樹脂などの熱硬化性樹脂、ポリアミド樹脂、ポリオレフィン樹脂、ジシクロペンタジエン樹脂、ポリウレタン樹脂等の熱可塑性樹脂が挙げられる。接着性から、エポキシ樹脂が好ましく使用される。
【００４３】
本発明に使用する繊維強化プラスチックとしては、炭素繊維とエポキシ樹脂からなる炭素繊維強化プラスチックは、軽量且つ力学特性に優れ、比弾性率、比強度が高いため、チタンを含む金属と組み合わせることにより、ハイブリッド効果が期待できるため、より好ましい。
【００４４】
本発明のコンポジット材料は、ＡＳＴＭ Ｄ １７８１−９８に準じて測定（以降、ＣＤＰ試験と記載する）したときの、チタンを含む金属と繊維強化プラスチック間の剥離に要する剥離トルクは５Ｎ・ｍｍ／ｍｍ以上であることが好ましい。より好ましくは１０Ｎ・ｍｍ／ｍｍ以上である。
【００４５】
剥離トルクが５Ｎ・ｍｍ／ｍｍ未満では、材料として接着性が不足することがあり、該コンポジット材料に荷重や衝撃が負荷された際に、剥離する恐れが生じる。
【００４６】
一般に、接着性を評価する時にはＪＩＳ Ｋ ６８５０「接着剤−剛性被着材の引張せん断接着強さ試験方法」に記載されているような引張せん断接着強さを試験することにより評価することが多い。しかしながらせん断接着強さは、実際に問題になる剥離強さと必ずしも対応するするものではない。せん断接着強さを向上できても、容易に剥離が起こることもあり、接着性に関しては、ＡＳＴＭ Ｄ １７８１−９８に準じ、剥離トルクを測定することが好ましいのである。
【００４７】
次に、本発明のコンポジット材料の好ましい製造方法について記載する。
【００４８】
本発明のコンポジット材料の好ましい製造方法は、チタンを含む金属の表面を、粒度が＃８０〜＃２０００の研磨材を用いてサンディング処理した後、イミダゾールシラン化合物を含む処理剤を前記サンディング処理面上に形成する工程を含むことである。該工程を含むことにより、コンポジットの接着強度を一層向上させることができる。
【００４９】
本発明のコンポジット材料の用途は、特に限定されないが、例えば、航空機用途、自動車用途、スポーツ用途、土木建築用途等に好適に使用される。
【００５０】
【実施例】
以下に本発明の実施例を記載するが、本発明はこれに限定されない。まず、使用した評価方法を記載する。
【００５１】
引張せん断試験およびＣＤＰ試験
チタン合金と炭素繊維強化プラスチックとの接着サンプルを用いて、引張せん断試験とＣＤＰ試験を行った。引張せん断試験片の作製及び試験方法はＪＩＳ Ｋ ６８５０に基づいて行った。また、ＣＤＰ試験片の作製及び試験方法はＡＳＴＭ Ｄ １７８１−９８に基づいて行った。
【００５２】
（実施例１）
まず引張せん断試験片の作製方法を説明する。図１に作製した引張せん断試験片の断面図を示す。
サンプルに用いたチタン合金１は、Ｔｉ−１５Ｖ−３Ｃｒ−３Ａｌ−３Ｓｎ合金であり、幅２５ｍｍ、長さ１００ｍｍ、厚み０．７ｍｍの形状に切断した。
次いで、イミダゾールシラン（日鉱マテリアル社製：ＩＳ４０００）をエタノールを用いて１．０％濃度に希釈して得られたイミダゾールシラン溶液を、接着面３（重ね合わせ長さ１２．５ｍｍ×幅２５ｍｍ）に塗布した後、常温でエタノールを揮発させて、チタン合金表面の接着面にイミダゾールシラン層を形成した。イミダゾールシラン層を形成した接着面３の上に、非繊維強化プラスチック境界層として、目付けが６０ｇ／ｍ²のエポキシ樹脂フィルム４を配し、更にその上に炭素繊維プリプレグ５を、長さが１２．５ｍｍとなるように重ね合わせた。ここで、炭素繊維プリプレグとしては、東レ（株）社製の炭素繊維Ｔ８００Ｈを強化繊維としたプリプレグを用いた。
次いで、重ね合わせ部を覆うように耐熱テープ（ニチバン（株）社製ポリエステルテープＮＯ．５５８Ａ）で仮止めをし、オートクレーブを用いて、６．０ｋｇ／ｃｍ²、１８０℃×２時間で炭素繊維プリプレグを硬化させると共に、チタン合金への接着を行い、引張せん断試験片を１０体作成した。
次にＣＤＰ試験片の作製方法を説明する。
図２に作製したＣＤＰ試験片の断面を示す。
サンプルに用いたチタン合金１は、同様にＴｉ−１５Ｖ−３Ｃｒ−３Ａｌ−３Ｓｎ合金であり、幅２５ｍｍ、長さ３００ｍｍ、厚み０．１３ｍｍの形状に切断した。
引張せん断試験片と同様に、チタン合金１の接着面３（重ね合わせ長さ２５０ｍｍ×幅２５ｍｍ）にイミダゾールシラン層を形成した。
【００５３】
イミダゾールシラン層を形成した接着面３の上に、非繊維強化プラスチック境界層として、目付けが６０ｇ／ｍ²のエポキシ樹脂フィルム４を配し、更にその上に炭素繊維プリプレグ５を長さ２６０ｍｍにわたり重ね合わせた。重ね合わせ部を覆うように耐熱テープで仮止めをし、オートクレーブを用いて、６．０ｋｇ／ｃｍ²、１８０℃×２時間で炭素繊維強化プリプレグを硬化させると共に、チタン合金への接着を行い、ＣＤＰ試験片を１０体作成した。
引張せん断試験片１０体のうち、５体はＪＩＳ Ｋ ６８５０に基づいて引張せん断試験を行い、５体の試験結果の平均値を引張せん断強度として求めた。残りの５体は、耐環境試験（以下、Ｈ／Ｗと記載する）として、５０℃×ＲＨ９５％に１４日間浸漬した後、室温にて同様に試験を行い、引張せん断強度を求めた。その結果、引張せん断強度は室温で２０．６ＭＰａ、Ｈ／Ｗで１８．９ＭＰａであった。ＣＤＰの剥離トルクは、室温で１５．０Ｎ・ｍｍ／ｍｍ、Ｈ／Ｗで１２．６ＭＰａであった。引張せん断試験、ＣＤＰ試験ともに、試験後の破断面には、ＣＦＲＰの母材破壊跡が観察された。
【００５４】
（実施例２）
チタン合金の接着面を粒度が＃４００のサンドパーパーを用いて研磨した他は実施例１と同様に引張せん断試験片、ＣＤＰ試験片を作成し、引張せん断強度、ＣＤＰの剥離トルクを求めた。
その結果、引張せん断強度は室温で２３．６ＭＰａ、Ｈ／Ｗで２１．８ＭＰａであった。ＣＤＰの剥離トルクは室温で１９．５Ｎ・ｍｍ／ｍｍ、Ｈ／Ｗで１８．４ＭＰａであった。引張せん断試験、ＣＤＰ試験ともに、試験後の破断面には、ＣＦＲＰの母材破壊跡が観察された。
【００５５】
（実施例３）
チタン合金の接着面を粒度が＃４００のサンドパーパーを用いて研磨し、非繊維強化樹脂として、平均粒径が１７μｍの熱可塑性樹脂粒子を含むエポキシ樹脂フィルムを用いた他は実施例１と同様にして、引張せん断試験片、ＣＤＰ試験片を作成し、引張せん断強度、ＣＤＰの剥離トルクを求めた。
その結果、引張せん断強度は室温で２５．６ＭＰａ、Ｈ／Ｗで２３．８ＭＰａであった。ＣＤＰの剥離トルクは室温で２３．５Ｎ・ｍｍ／ｍｍ、Ｈ／Ｗで２０．１ＭＰａであった。引張せん断試験、ＣＤＰ試験ともに、試験後の破断面には、ＣＦＲＰの母材破壊跡が観察された。
【００５６】
（比較例１）
チタン合金の接着面にイミダゾールシランを付与せず、非繊維強化樹脂としてエポキシ樹脂フィルムを配さない他は実施例１と同様に引張せん断試験片、ＣＤＰ試験片を作成し、引張せん断強度、ＣＤＰの剥離トルクを求めた。
その結果、引張せん断強度は室温で１４．１ＭＰａ、Ｈ／Ｗで８．２ＭＰａであった。ＣＤＰの剥離トルクは室温Ｈ／Ｗともにほとんど検出できないレベルであった。引張せん断試験後の破断面には、ＣＦＲＰの母材破壊跡は観察されなかった。またＣＤＰ試験後の破断面にもＣＦＲＰの母材破壊跡は観察されなかった。
【００５７】
（比較例２）
チタン合金の接着面にイミダゾールシランを付与しない他は実施例１と同様に引張せん断試験片、ＣＤＰ試験片を作成し、引張せん断強度、ＣＤＰの剥離トルクを求めた。
その結果、引張せん断強度は室温で１５．８ＭＰａ、Ｈ／Ｗで１１．３ＭＰａであった。ＣＤＰの剥離トルクは室温で１．９Ｎ・ｍｍ／ｍｍ、Ｈ／Ｗで１．４Ｎ・ｍｍ／ｍｍであった。引張せん断試験後の破断面には、ＣＦＲＰの母材破壊跡は観察されなかった。またＣＤＰ試験後の破断面にもＣＦＲＰの母材破壊跡は観察されなかった。
【００５８】
（比較例３）
非繊維強化樹脂としてエポキシ樹脂フィルムを配さない他は実施例１と同様に引張せん断試験片、ＣＤＰ試験片を作成し、引張せん断強度、ＣＤＰの剥離トルクを求めた。
その結果、引張せん断強度は室温で１７．５ＭＰａ、Ｈ／Ｗで１５．２ＭＰａであった。ＣＤＰの剥離トルクは室温で５．４Ｎ・ｍｍ／ｍｍ、Ｈ／Ｗで４．６Ｎ・ｍｍ／ｍｍであった。引張せん断試験後の破断面には、一部ＣＦＲＰの母材破壊跡が観察されたが、ＣＤＰ試験後のの破断面には、ＣＦＲＰの母材破壊跡はほとんど観察されなかった。
【００５９】
（比較例４）
非繊維強化樹脂としてエポキシ樹脂フィルムを配さない他は実施例２と同様に引張せん断試験片、ＣＤＰ試験片を作成し、引張せん断強度、ＣＤＰの剥離トルクを求めた。
その結果、引張せん断強度は室温で１８．９ＭＰａ、Ｈ／Ｗで１６．２ＭＰａであった。ＣＤＰの剥離トルクは室温で６．７Ｎ・ｍｍ／ｍｍ、Ｈ／Ｗで４．９Ｎ・ｍｍ／ｍｍであった。引張せん断試験後の破断面には、一部ＣＦＲＰの母材破壊跡が観察されたが、ＣＤＰ試験後の破断面にはＣＦＲＰの母材破壊跡は観察されなかった。
【００６０】
（比較例５）
イミダゾールシランの代わりに、エポキシシラン（信越化学社製：ＫＢＭ−４０３）をエタノールを用いて１．０％濃度に希釈して得られたエポキシシラン溶液を用いた他は実施例２と同様に引張せん断試験片、ＣＤＰ試験片を作成し、引張せん断強度、ＣＤＰの剥離トルクを求めた。
その結果、引張せん断強度は室温で１７．２ＭＰａ、Ｈ／Ｗで１３．３ＭＰａであった。ＣＤＰの剥離トルクは室温で２．１Ｎ・ｍｍ／ｍｍ、Ｈ／Ｗで１．４Ｎ・ｍｍ／ｍｍであった。引張せん断試験後の破断面には、ＣＦＲＰの母材破壊跡は観察されなかった。また、ＣＤＰ試験後の破断面にもＣＦＲＰの母材破壊跡は観察されなかった。
【００６１】
以上の結果を、表１に纏めて記載した。
【００６２】
【表１】

【００６３】
表１から分かるように、チタン合金の接着表面にイミダゾールシランを有し、且つ非繊維強化プラスチック境界層を有する実施例１〜３はいずれもＣＤＰの剥離トルクが室温では１５．０Ｎ・ｍｍ／ｍｍ以上、Ｈ／Ｗでも１２．６Ｎ・ｍｍ／ｍｍ以上であり、破断後のチタン合金の接着表面にはＣＦＲＰの母材破壊の跡が確認され、良好な接着性を発現していることが分かった。
【００６４】
一方、チタン合金の接着表面にイミダゾールシランを有しない比較例１，２はいずれもＣＤＰの剥離トルクが２Ｎ・ｍｍ／ｍｍ以下であり、簡単に剥離し、破断後のチタン合金の接着表面にはＣＦＲＰの母材破壊の跡は確認されず、接着性が悪いことが分かった。
【００６５】
また、チタン合金の接着表面にイミダゾールシランを有しても、非繊維強化プラスチック境界層を有しない比較例３，４はいずれもＣＤＰの剥離トルクが比較例１，２よりも若干向上しているものの、７Ｎ・ｍｍ／ｍｍ以下であり、破断後のチタン合金の接着面ンにはＣＦＲＰの母材破壊の跡は確認されず、接着性が悪いことが分かった。
【００６６】
またチタン合金の接着表面にイミダゾールシランの代わりにエポキシシランを有する比較例５は、ＣＤＰの剥離トルクが３Ｎ・ｍｍ／ｍｍ以下であり、簡単に剥離し、破断後のチタン合金の接着面ンにはＣＦＲＰの母材破壊の跡は確認されず、接着性が悪いことが分かった。
【００６７】
【発明の効果】
以上説明したように、本発明によれば、室温及び高温高湿度暴露後においても安定で良好な接着強度を有するコンポジット材料を提供することができ、特にＣＤＰの剥離トルクを大幅に向上させることができるため、自動車部材、建材、航空機部材、スポーツ用具部材等に好適に用いることができる。
【図面の簡単な説明】
【図１】本発明のコンポジット材料を使用した引張せん断試験片の一例を示す断面図である。
【図２】本発明のコンポジット材料を使用したＣＤＰ試験片の一例を示す断面図である。
【符号の説明】
１……チタン合金
２……イミダゾールシラン
３……接着面
４……エポキシ樹脂フィルム
５……炭素繊維プリプレグ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composite material, and more particularly to a composite material composed of a metal containing titanium and a fiber reinforced plastic that is suitably used for, for example, an automobile member, a building material, an aircraft member, a sports equipment member, and the like, and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, titanium alloys have high mechanical properties such as specific strength (tensile strength / specific gravity), specific modulus (elastic modulus / specific gravity), and excellent corrosion resistance, so that not only special fields such as space and ocean, Recently, it has been attracting attention in general industrial applications or medical fields, and its demand is increasing year by year.
[0003]
In addition, fiber reinforced plastic consisting of reinforced fiber and matrix resin has high specific strength and specific modulus, excellent mechanical properties such as impact resistance, and functional properties such as weather resistance, chemical resistance, and conductive properties. In addition, in the use of continuous reinforcing fibers, the fiber content and laminated structure, in the case of discontinuous fibers, by appropriately designing the fiber length, fiber content, etc., the physical properties according to the application can be expressed, etc. There are benefits.
[0004]
Therefore, a composite material composed of a titanium alloy and a fiber reinforced plastic is expected to exhibit high mechanical characteristics and high functional characteristics that cannot be expressed by a titanium alloy alone or a fiber reinforced plastic alone due to a hybrid effect.
[0005]
Generally, a composite material obtained by combining dissimilar materials such as a composite material made of titanium alloy and fiber reinforced plastic has a sufficiently high adhesive strength between dissimilar materials so that the composite material exhibits high mechanical properties. It is assumed that each material can bear enough stress against the applied load.
[0006]
However, in titanium alloys, it has been found that an oxide coating made of brittle titanium oxide formed on the surface of the titanium alloy hinders improvement in adhesive strength. For this reason, composite materials made of titanium alloy and fiber reinforced plastic have the potential to develop high mechanical properties and high functional properties, but they are not widely used because of their low adhesive strength. Yes.
[0007]
Thus, a surface treatment method for improving the adhesiveness of the titanium alloy has been proposed (see, for example, Patent Document 1). According to this method, a titanium alloy is immersed in a normal temperature bath of a mixed aqueous solution of hydrofluoric acid and nitric acid for a predetermined time to remove the oxide film formed on the surface, and the titanium alloy is formed with an sodium hydroxide solution to form an anodic oxide film. Thus, it is described that the adhesiveness when the titanium alloy material is bonded to another material can be improved.
[0008]
Moreover, anodized film is formed on the surface by anodizing the titanium alloy in phosphoric acid-sulfuric acid aqueous solution at a voltage higher than the spark discharge generation voltage, and then the oxide film is reduced by heating in a vacuum atmosphere. There has been proposed a surface treatment method including a step of making a metal state (see, for example, Patent Document 2).
[0009]
However, these methods have the following problems. That is, in Patent Documents 1 and 2, since an acidic aqueous solution such as hydrofluoric acid or phosphoric acid is used, handling is very difficult, and the treated titanium alloy is left in the air. Since a brittle oxide film is formed on the anodized film that contributes to improved adhesion on the surface of the titanium alloy, good adhesion strength cannot be obtained even if an adhesion treatment is performed on the anodized film. There is a problem that it is necessary to perform an adhesion treatment immediately after the treatment.
[0010]
Also, since the bonding process is usually performed in the air in order to simplify the equipment, the oxidation of the anodized titanium and titanium alloy surface proceeds even during the bonding process. There was a problem that the adhesive strength of the street could not be expressed.
[0011]
Furthermore, when the composite which is an adhesive body is exposed in a high-temperature and high-humidity atmosphere as an environmental resistance test, there is a problem that the adhesive strength is remarkably reduced, and the adhesive part is peeled off only by cutting the adhesive body.
[0012]
[Patent Document 1]
JP 2002-129387A (page 1-2)
[0013]
[Patent Document 2]
JP 2002-252687 A (page 1-2)
[0014]
[Problems to be solved by the invention]
An object of the present invention is to provide a composite material composed of a metal containing titanium and a fiber reinforced plastic, which has a stable and good adhesive strength even after exposure to room temperature and high temperature and high humidity, and a method for producing the same, in view of the above-mentioned problems of the prior art It is to be.
[0015]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configuration. That is, the present invention
A composite material in which a metal containing titanium, a compound containing imidazole silane represented by the following chemical formula, a non-fiber reinforced plastic, and a fiber reinforced plastic are formed in this order is the essence.
[0016]
[Chemical 2]

[0017]
(R ¹ and R ² are alkyl groups having 1 to 3 carbon atoms (n = 1 to 3), and R ³ is a bond itself or an aliphatic group having 1 to 20 carbon atoms. R ⁴ and R ⁵ and R ⁶ may be the same or different and each represents hydrogen or an aliphatic group having 1 to 20 carbon atoms).
[0018]
DETAILED DESCRIPTION OF THE INVENTION
As the metal containing titanium used in the present invention, pure titanium or a titanium alloy can be used. Here, as the titanium alloy, any of so-called α alloy, β alloy, and α + β alloy system having both layers can be used. Among these, a β alloy Ti-15V-3Cr-3Al-3Sn alloy and an α + β alloy Ti-6Al-4V alloy, which are easy to obtain high strength at normal operating temperatures, are preferably used.
[0019]
The shape of the metal containing titanium is not particularly limited and may be any of a plate shape, a rod shape, and a thread shape. Since the plate-like material has a wide adhesion area, the effect of improving the adhesiveness is remarkably exhibited, so that it is preferably used.
[0020]
The present invention is a composite material in which a metal containing titanium, a compound containing a specific imidazole silane, a non-fiber reinforced plastic, and a fiber reinforced plastic are formed in this order, but the processes for forming each constituent component use known processes. can do. For example, a method of applying a compound containing imidazole silane to a metal surface containing titanium, drying and then molding the fiber reinforced plastic so as to sandwich the non-fiber reinforced plastic is preferably used.
[0021]
In the present invention, a compound containing imidazole silane represented by the following chemical formula needs to be present on at least a part of the metal surface containing titanium.
[0022]
[Chemical 3]

[0023]
(R ¹ and R ² are alkyl groups having 1 to 3 carbon atoms (n = 1 to 3), and R ³ is a bond itself or an aliphatic group having 1 to 20 carbon atoms. R ⁴ and R ⁵ and R ⁶ may be the same or different and each has hydrogen or an aliphatic group having 1 to 20 carbon atoms).
[0024]
Specific examples of the imidazole silane represented by the above chemical formula include the following chemical formula group.
[0025]
[Formula 4]

[0026]
[Chemical formula 5]

[0027]
[Chemical 6]

[0028]
(Here, in the above three chemical formula groups, R ¹ is hydrogen or an alkyl group having 1 to 20 carbon atoms. R ² is hydrogen, a vinyl group or an alkyl group having 1 to 5 carbon atoms. ³ and R ⁴ are alkyl groups having 1 to 3 carbon atoms, and n is an integer selected from 1 to 3).
[0029]
The compound containing imidazole silane used in the present invention may be composed of 100% imidazole silane, and contains other components such as a plasticizer for the purpose of improving handling properties. Also good.
[0030]
Although it does not specifically limit as a method of forming the compound containing imidazole silane on the surface of the metal containing titanium, for example, imidazole silane is diluted with water or a solvent such as ethanol, methanol at a concentration of 0.1 to 10%, A method of applying the diluted solution to the metal surface by coating or dipping is preferably used. Also, spraying up the diluted solution can be used. Here, components other than imidazole silane can be added to the solution in order to improve applicability and the like.
[0031]
After applying the solution, it is preferable to volatilize a part or all of water or a solvent such as ethanol or methanol by standing at room temperature or heating or reducing the pressure.
[0032]
In the present invention, a non-fiber reinforced plastic is formed between the imidazole silane represented by the chemical formula and the fiber reinforced plastic. When the boundary layer made of this non-fiber reinforced plastic acts as a stress buffer material, when a load or impact is applied to the composite material, it acts as a stress relaxation layer, so that the metal containing titanium and the fiber reinforced plastic Can be prevented.
[0033]
The formation shape of the non-fiber reinforced plastic is not particularly limited, but is preferably a layered shape. The thickness of the layer is preferably in the range of 0.01 mm to 0.1 mm, more preferably in the range of 0.015 mm to 0.05 mm, most preferably from the balance between stress relaxation and weight reduction. Is in the range of 0.015 mm to 0.025 mm. If the boundary layer made of non-fiber reinforced plastic is thinner than 0.01 mm, the stress relaxation becomes small and the possibility of peeling increases, and conversely, if it is too thick, there may be a problem of weight increase. is there.
[0034]
The plastic material used as the non-fiber reinforced plastic is not particularly limited, and a known thermoplastic resin, thermosetting resin, or the like can be used. A thermosetting resin is preferable, and an epoxy resin is more preferable.
[0035]
The non-fiber reinforced plastic is preferably the same as or similar to the material used for the fiber reinforced plastic from the viewpoint of adhesion between the metal containing titanium and the fiber reinforced plastic.
[0036]
When an epoxy resin is used as the non-fiber reinforced plastic, it is also a preferable aspect to include a thermoplastic plastic or a thermoplastic elastomer in the non-fiber reinforced plastic for the purpose of reinforcing the composite material or imparting toughness. .
[0037]
Here, as the thermoplastic plastic, polyimide (PI), polyetherimide (PEI), polyamide (PA), polyamideimide (PAI), polyethersulfone (PES), polyetherethersulfone (PEES), etc. are preferably used. Is done.
[0038]
As the thermoplastic elastomer, ionomer (IO), polyolefin (TPO), urethane (TPU), polyamide (TPAE), polyvinyl chloride (TPVC), and the like are preferably used.
[0039]
These thermoplastic resins and thermoplastic elastomers are preferably used in the form of particles or nonwoven fabric.
[0040]
In the present invention, the fiber reinforced plastic is a general term for a thermoplastic resin or a thermosetting plastic composite material reinforced with continuous or discontinuous reinforcing fibers. The average fiber volume content of the fiber reinforced plastic is not particularly limited, but is preferably in the range of 20 to 75%, and more preferably in the range of 45 to 65%.
[0041]
The kind of fiber used for the fiber reinforced plastic is not particularly limited, and examples thereof include inorganic fibers such as carbon fibers and glass fibers, or organic fibers such as Kevlar fibers, polyethylene fibers, polyamide fibers, and aramid fibers. Carbon fiber is preferably used in terms of light weight and mechanical properties.
[0042]
The plastic used for the fiber reinforced plastic is not particularly limited, and examples thereof include thermosetting resins such as epoxy resins, polyester resins, vinyl ester resins, and phenol resins, polyamide resins, polyolefin resins, dicyclopentadiene resins, polyurethane resins, and the like. A thermoplastic resin is mentioned. From the viewpoint of adhesiveness, an epoxy resin is preferably used.
[0043]
As the fiber reinforced plastic used in the present invention, the carbon fiber reinforced plastic made of carbon fiber and epoxy resin is lightweight and excellent in mechanical properties, and has a high specific elastic modulus and specific strength. Since a hybrid effect can be expected, it is more preferable.
[0044]
The composite material of the present invention has a peeling torque of 5 N · mm / mm required for peeling between the metal containing titanium and the fiber reinforced plastic when measured according to ASTM D 1781-98 (hereinafter referred to as CDP test). The above is preferable. More preferably, it is 10 N · mm / mm or more.
[0045]
When the peeling torque is less than 5 N · mm / mm, the adhesiveness may be insufficient as a material, which may cause peeling when a load or impact is applied to the composite material.
[0046]
Generally, when evaluating adhesiveness, it is often evaluated by testing the tensile shear adhesive strength as described in JIS K 6850 "Testing method for tensile shear adhesive strength of adhesive-rigid substrate". . However, the shear bond strength does not necessarily correspond to the peel strength that is actually a problem. Even if the shear bond strength can be improved, peeling may occur easily. Regarding the adhesiveness, it is preferable to measure the peeling torque in accordance with ASTM D 1781-98.
[0047]
Next, the preferable manufacturing method of the composite material of this invention is described.
[0048]
In a preferred method for producing the composite material of the present invention, the surface of a metal containing titanium is subjected to a sanding treatment using an abrasive having a particle size of # 80 to # 2000, and then a treating agent containing an imidazole silane compound is applied on the sanding treatment surface. The process to form in is included. By including this step, the adhesive strength of the composite can be further improved.
[0049]
Although the use of the composite material of this invention is not specifically limited, For example, it uses suitably for an aircraft use, a motor vehicle use, a sports use, a civil engineering building use etc.
[0050]
【Example】
Although the Example of this invention is described below, this invention is not limited to this. First, the evaluation method used is described.
[0051]
Tensile shear test and CDP test A tensile shear test and a CDP test were conducted using an adhesion sample of a titanium alloy and a carbon fiber reinforced plastic. The tensile shear test piece was prepared and tested in accordance with JIS K 6850. The CDP test piece was prepared and tested according to ASTM D 1781-98.
[0052]
(Example 1)
First, a method for producing a tensile shear test piece will be described. FIG. 1 shows a cross-sectional view of the tensile shear test piece prepared.
The titanium alloy 1 used for the sample was a Ti-15V-3Cr-3Al-3Sn alloy, and was cut into a shape having a width of 25 mm, a length of 100 mm, and a thickness of 0.7 mm.
Next, an imidazole silane solution obtained by diluting imidazole silane (manufactured by Nikko Materials Co., Ltd .: IS4000) to a concentration of 1.0% using ethanol is applied to the bonding surface 3 (overlapping length 12.5 mm × width 25 mm). After coating, ethanol was volatilized at room temperature to form an imidazole silane layer on the adhesive surface of the titanium alloy surface. An epoxy resin film 4 having a basis weight of 60 g / m ² is arranged as a non-fiber reinforced plastic boundary layer on the adhesive surface 3 on which the imidazole silane layer is formed, and a carbon fiber prepreg 5 is further formed thereon with a length of 12 Overlapped to be 5 mm. Here, as the carbon fiber prepreg, a prepreg using carbon fiber T800H manufactured by Toray Industries, Inc. as a reinforcing fiber was used.
Next, carbon fiber is temporarily fixed with a heat-resistant tape (polyester tape No. 558A manufactured by Nichiban Co., Ltd.) so as to cover the overlapped portion, and is 6.0 kg / cm ² at 180 ° C. × 2 hours using an autoclave. While hardening the prepreg, adhesion to a titanium alloy was performed, and ten tensile shear test pieces were prepared.
Next, a method for producing a CDP test piece will be described.
FIG. 2 shows a cross section of the CDP test piece produced.
The titanium alloy 1 used for the sample was similarly a Ti-15V-3Cr-3Al-3Sn alloy, and was cut into a shape having a width of 25 mm, a length of 300 mm, and a thickness of 0.13 mm.
Similar to the tensile shear test piece, an imidazolesilane layer was formed on the adhesive surface 3 of the titanium alloy 1 (overlap length 250 mm × width 25 mm).
[0053]
An epoxy resin film 4 having a basis weight of 60 g / m ² is arranged as a non-fiber reinforced plastic boundary layer on the adhesive surface 3 on which the imidazole silane layer is formed, and a carbon fiber prepreg 5 is further laminated thereon over a length of 260 mm. Combined. Temporarily fix with heat-resistant tape so as to cover the overlapped part, and use an autoclave to cure the carbon fiber reinforced prepreg at 6.0 kg / cm ² , 180 ° C. × 2 hours, and adhere to the titanium alloy, Ten CDP test pieces were prepared.
Of the ten tensile shear test pieces, five were subjected to a tensile shear test based on JIS K 6850, and the average value of the test results of the five bodies was determined as the tensile shear strength. The remaining five bodies were immersed in 50 ° C. × RH 95% for 14 days as an environmental resistance test (hereinafter referred to as “H / W”) and then tested in the same manner at room temperature to obtain tensile shear strength. As a result, the tensile shear strength was 20.6 MPa at room temperature and 18.9 MPa at H / W. The peeling torque of CDP was 15.0 N · mm / mm at room temperature and 12.6 MPa at H / W. In both the tensile shear test and the CDP test, the fracture surface of the CFRP base material was observed on the fracture surface after the test.
[0054]
(Example 2)
A tensile shear test piece and a CDP test piece were prepared in the same manner as in Example 1 except that the bonded surface of the titanium alloy was polished using a sand perper with a particle size of # 400, and the tensile shear strength and the CDP peeling torque were determined.
As a result, the tensile shear strength was 23.6 MPa at room temperature and 21.8 MPa at H / W. The peeling torque of CDP was 19.5 N · mm / mm at room temperature and 18.4 MPa at H / W. In both the tensile shear test and the CDP test, the fracture surface of the CFRP base material was observed on the fracture surface after the test.
[0055]
(Example 3)
The bonded surface of the titanium alloy was polished using a sand perpery having a particle size of # 400, and an epoxy resin film containing thermoplastic resin particles having an average particle size of 17 μm was used as a non-fiber reinforced resin, as in Example 1. Thus, tensile shear test pieces and CDP test pieces were prepared, and tensile shear strength and CDP peeling torque were determined.
As a result, the tensile shear strength was 25.6 MPa at room temperature and 23.8 MPa at H / W. The peeling torque of CDP was 23.5 N · mm / mm at room temperature and 20.1 MPa at H / W. In both the tensile shear test and the CDP test, the fracture surface of the CFRP base material was observed on the fracture surface after the test.
[0056]
(Comparative Example 1)
A tensile shear test piece and a CDP test piece were prepared in the same manner as in Example 1 except that no imidazole silane was applied to the adhesive surface of the titanium alloy and no epoxy resin film was provided as a non-fiber reinforced resin. The peel torque was determined.
As a result, the tensile shear strength was 14.1 MPa at room temperature and 8.2 MPa at H / W. The peeling torque of CDP was a level that could hardly be detected at both room temperature H / W. No CFRP base metal fracture marks were observed on the fracture surface after the tensile shear test. Also, no CFRP base metal fracture trace was observed on the fracture surface after the CDP test.
[0057]
(Comparative Example 2)
A tensile shear test piece and a CDP test piece were prepared in the same manner as in Example 1 except that imidazole silane was not applied to the adhesive surface of the titanium alloy, and tensile shear strength and CDP peeling torque were determined.
As a result, the tensile shear strength was 15.8 MPa at room temperature and 11.3 MPa at H / W. The peeling torque of CDP was 1.9 N · mm / mm at room temperature and 1.4 N · mm / mm at H / W. No CFRP base metal fracture marks were observed on the fracture surface after the tensile shear test. Also, no CFRP base metal fracture trace was observed on the fracture surface after the CDP test.
[0058]
(Comparative Example 3)
A tensile shear test piece and a CDP test piece were prepared in the same manner as in Example 1 except that no epoxy resin film was disposed as a non-fiber reinforced resin, and the tensile shear strength and CDP peeling torque were determined.
As a result, the tensile shear strength was 17.5 MPa at room temperature and 15.2 MPa at H / W. The peeling torque of CDP was 5.4 N · mm / mm at room temperature and 4.6 N · mm / mm at H / W. On the fracture surface after the tensile shear test, a part of the CFRP base material fracture trace was observed, but on the fracture surface after the CDP test, almost no CFRP base material fracture trace was observed.
[0059]
(Comparative Example 4)
A tensile shear test piece and a CDP test piece were prepared in the same manner as in Example 2 except that an epoxy resin film was not used as the non-fiber reinforced resin, and the tensile shear strength and CDP peeling torque were determined.
As a result, the tensile shear strength was 18.9 MPa at room temperature and 16.2 MPa at H / W. The peeling torque of CDP was 6.7 N · mm / mm at room temperature and 4.9 N · mm / mm at H / W. On the fracture surface after the tensile shear test, a CFRP base material fracture trace was partially observed, but no CFRP base material fracture trace was observed on the fracture surface after the CDP test.
[0060]
(Comparative Example 5)
Tensile tension was the same as in Example 2 except that an epoxy silane solution obtained by diluting epoxy silane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM-403) to 1.0% concentration with ethanol was used instead of imidazole silane. Shear test pieces and CDP test pieces were prepared, and tensile shear strength and CDP peeling torque were determined.
As a result, the tensile shear strength was 17.2 MPa at room temperature and 13.3 MPa at H / W. The peeling torque of CDP was 2.1 N · mm / mm at room temperature and 1.4 N · mm / mm at H / W. No CFRP base metal fracture marks were observed on the fracture surface after the tensile shear test. Also, no CFRP base metal fracture trace was observed on the fracture surface after the CDP test.
[0061]
The above results are summarized in Table 1.
[0062]
[Table 1]

[0063]
As can be seen from Table 1, Examples 1 to 3 having imidazole silane on the adhesive surface of the titanium alloy and having a non-fiber reinforced plastic boundary layer are all 15.0 N · mm / mm at a CDP peeling torque at room temperature. As described above, even H / W is 12.6 N · mm / mm or more, and the fracture surface of the CFRP base material is confirmed on the bonded surface of the titanium alloy after the fracture, and it is found that good adhesiveness is expressed. It was.
[0064]
On the other hand, in Comparative Examples 1 and 2 that do not have imidazole silane on the adhesive surface of the titanium alloy, the CDP peel torque is 2 N · mm / mm or less. The trace of the base material destruction of CFRP was not confirmed, and it was found that the adhesiveness was poor.
[0065]
Moreover, even if it has imidazole silane on the adhesion surface of a titanium alloy, the comparative examples 3 and 4 which do not have a non-fibre-reinforced plastic boundary layer are slightly improved in the CDP peeling torque compared to the comparative examples 1 and 2. However, it was 7 N · mm / mm or less, and the trace of the CFRP base material was not confirmed on the adhesive surface of the titanium alloy after the fracture, indicating that the adhesion was poor.
[0066]
Further, in Comparative Example 5 having epoxy silane instead of imidazole silane on the adhesive surface of the titanium alloy, the CDP peeling torque is 3 N · mm / mm or less, and it is easily peeled off. No trace of CFRP matrix destruction was found, indicating that the adhesion was poor.
[0067]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a composite material having a stable and good adhesive strength even after exposure to room temperature and high temperature and high humidity, and in particular, it can greatly improve the peeling torque of CDP. Therefore, it can be suitably used for automobile members, building materials, aircraft members, sports equipment members, and the like.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a tensile shear test piece using a composite material of the present invention.
FIG. 2 is a cross-sectional view showing an example of a CDP test piece using the composite material of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Titanium alloy 2 ... Imidazole silane 3 ... Adhesion surface 4 ... Epoxy resin film 5 ... Carbon fiber prepreg

Claims (6)

A composite material in which a metal containing titanium, a compound containing imidazole silane represented by the following chemical formula, a non-fiber reinforced plastic, and a fiber reinforced plastic are formed in this order.

(R ¹ and R ² are alkyl groups having 1 to 3 carbon atoms (n = 1 to 3), and R ³ is a bond itself or an aliphatic group having 1 to 20 carbon atoms. R ⁴ and R ⁵ and R ⁶ may be the same or different and each represents hydrogen or an aliphatic group having 1 to 20 carbon atoms. The composite material according to claim 1, wherein the fiber reinforced plastic is a carbon fiber reinforced plastic. The composite material according to claim 1 or 2, wherein the plastic used for the non-fiber reinforced plastic is an epoxy resin. The composite material according to claim 3, wherein the epoxy resin includes a thermoplastic resin. The composite material according to any one of claims 1 to 4, wherein a peeling torque when measured according to ASTM D 1781-98 is 5 N · mm / mm or more. It is a manufacturing method of the composite material in any one of Claims 1-5, Comprising: After sanding the surface of the metal containing titanium using the abrasive | polishing material with a particle size of # 80- # 2000, imidazole silane is included. A method for producing a composite material, comprising a step of forming a compound on the sanding surface.

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