JP3931788B2 - Elastic paving material - Google Patents

Description

【０００８】
すなわち、本発明者らは、ウレタン系バインダーと弾性骨材との密着性が良好で、高いすべり摩擦係数（μｗｅｔ）を長期間維持することができる弾性舗装材を得るため鋭意研究を重ねた。そして、まず、ウレタン系バインダーに着目し、そのポリオール成分を中心に研究を重ねた結果、ポリオール成分に、水酸基両末端ポリブタジエンを用いると、ウレタン系バインダーと弾性骨材との密着性が高められることを突き止めた。この理由は、上記水酸基両末端ポリブタジエンの分子骨格が、タイヤ等のゴム材料等に使用されているポリブタジエンや天然ゴムの分子骨格と、同じまたは類似しているため、すなわち両者の極性が近く、相溶性が高いため、水酸基両末端ポリブタジエンとゴム材料等とのなじみ、濡れ性が良好となり、密着性が高くなることによるものと思われる。また、水酸基両末端ポリブタジエンのウレタン系バインダーの全重量に対する比率について研究を重ねた結果、上記式（１）で表される水酸基両末端ポリブタジエン構造部分の含有量を、３０〜５０重量％の範囲内に設定すると、所期の目的を達成できることを見いだし、本発明に到達した。すなわち、水酸基両末端ポリブタジエンのウレタン系バインダーの全重量に対する比率を、上記所定の範囲に設定すると、ウレタン系バインダーと弾性骨材との密着性を高めることができ、弾性舗装材が長期間にわたって屋外に曝露されることによってバインダーが硬化しても、弾性骨材等との密着性の低下が抑えられる。そのため、弾性舗装材を車両が通過することにより、タイヤトレッドと弾性舗装材表面とが摩擦しても、弾性骨材表面からのバインダーや硬質骨材の離脱が抑えられ、弾性骨材表面の露出が抑制される。その結果、濡れた状態での弾性舗装材のすべり摩擦係数が適正に維持され、降雨時の濡れた路面上での車両のスリップ発生を防止することができる。
【０００９】
【発明の実施の形態】
つぎに、本発明の実施の形態を詳しく説明する。
【００１０】
本発明の弾性舗装材は、弾性骨材（Ａ成分）と、硬質骨材（Ｂ成分）と、特定のウレタン系バインダー（Ｃ成分）とを用いて成形されてなるものである。
【００１１】
上記弾性骨材（Ａ成分）としては、特に限定はなく、天然ゴム、合成ゴム等のゴム材料や、熱可塑性エラストマー、発泡ポリウレタン等の弾性を有する合成樹脂材料等を、ひじき状、粒状等のチップ形状に粉砕したものが用いられる。これらは単独でもしくは２種以上併せて用いられる。上記合成ゴムとしては、特に限定はなく、例えば、スチレン−ブタジエンゴム（ＳＢＲ）、アクリロニトリルブタジエンゴム（ＮＢＲ）、エチレン−プロピレン−ジエン三元共重合体（ＥＰＤＭ）、ブタジエンゴム（ＢＲ）、クロロプレンゴム（ＣＲ）や、これらのブレンドゴム等があげられる。これらのなかでも、資源再利用の観点から、廃タイヤより作製されるゴムチップ等が好適に用いられる。なお、その他の骨材も、必要に応じて併用しても差し支えない。
【００１２】
上記弾性骨材（Ａ成分）とともに用いられる硬質骨材（Ｂ成分）としては、無機材料や有機材料に限らないが、無機材料としては砕石、珪砂、砂、シリカ、ガラス等が、有機材料としてはナイロン、ウレタン等の樹脂材料等があげられる。これらは単独でもしくは２種以上併せて用いられる。これらのなかでも、入手のしやすさ、コストの点で、砕石または珪砂が好適に用いられる。
【００１３】
上記硬質骨材（Ｂ成分）の平均粒径は、０．０１〜２．５ｍｍの範囲内が好ましく、特に好ましくは０．０１〜０．５ｍｍの範囲内である。すなわち、上記硬質骨材（Ｂ成分）の平均粒径が０．０１ｍｍ未満であると、弾性舗装材の加工性が悪くなる傾向がみられ、逆に２．５ｍｍを超えると、濡れ時のすべり摩擦係数が低いため、多量の添加が必要となるからである。
【００１４】
上記硬質骨材（Ｂ成分）の配合量は、上記弾性骨材（Ａ成分）と硬質骨材（Ｂ成分）とウレタン系バインダー（Ｃ成分）の合計量全体の５〜３５重量％の範囲内に設定することが好ましく、特に好ましくは１５〜３０重量％の範囲内である。すなわち、上記硬質骨材（Ｂ成分）の配合量が５重量％未満であると、濡れ時のすべり摩擦係数（μｗｅｔ）が小さすぎる傾向がみられ、逆に、上記硬質骨材（Ｂ成分）の配合量が３５重量％を超えると、弾性舗装材の強度が低下する傾向がみられるからである。
【００１５】
上記弾性骨材（Ａ成分）および硬質骨材（Ｂ成分）とともに用いられるウレタン系バインダー（Ｃ成分）としては、例えば、ポリオール成分の水酸基両末端ポリブタジエンと、芳香族系ポリイソシアネート成分とを反応させて得られるウレタンプレポリマー等があげられる。
【００１６】
上記ポリオール成分とともに用いられる芳香族系ポリイソシアネート成分としては、特に限定はなく、例えば、４，４′−ジフェニルメタンジイソシアネート（ＭＤＩ）、２，４−トリレンジイソシアネート（２，４−ＴＤＩ）、２，６−トリレンジイソシアネート（２，６−ＴＤＩ）、３，３′−ビトリレン−４，４′−ジイソシアネート、３，３′−ジメチルジフェニルメタン−４，４′−ジイソシアネート、２，４−トリレンジイソシアネートウレチジンジオン（２，４−ＴＤＩの二量体）、１，５−ナフチレンジイソシアネート、メタフェニレンジイソシアネート、カルボジイミド変性ＭＤＩ、オルトトルイジンジイソシアネート、キシレンジイソシアネート、パラフェニレンジイソシアネート等のジイソシアネート、トリフェニルメタン−４，４′，４″−トリイソシアネート等のトリイソシアネート、ポリメリックＭＤＩ等があげられる。これらは単独でもしくは２種以上併せて用いられる。
【００１７】
上記ウレタン系バインダー（Ｃ成分）としては、前記式（１）で表される水酸基両末端ポリブタジエン構造部分の含有量（ジエン含有量）が、３０〜５０重量％の範囲内に設定されているものを用いる必要がある。すなわち、ジエン含有量が３０重量％未満であると、ゴムチップ等の弾性骨材（Ａ成分）との密着性が悪化し、逆にジエン含有量が５０重量％を超えると、弾性舗装材の強度が低下するからである。なお、水酸基両末端ポリブタジエンを主成分とするポリオール成分の重量とは、通常、水酸基末端ポリブタジエンの重量であるが、後述するように、水酸基両末端ポリブタジエンとともに、ポリプロピレングリコール（ＰＰＧ）やポリテトラメチレンエーテルグリコール（ＰＴＭＥＧ）を併用する場合は、これらの合計重量がポリオール成分の重量となる。
【００１８】
【数３】

【００１９】
上記ジエン含有量が特定の範囲内に設定されたウレタン系バインダー（Ｃ成分）は、ポリオール成分である水酸基両末端ポリブタジエンと、芳香族系ポリイソシアネート成分とを、重量基準で、水酸基両末端ポリブタジエン／芳香族系ポリイソシアネート成分＝３０／５０〜５０／３０の範囲内で配合して、プレポリマーを合成することにより得ることができる。
【００２０】
なお、上記ウレタン系バインダー（Ｃ成分）は、水酸基両末端ポリブタジエン構造部分の含有量が所定の範囲内にあれば、ポリオール成分として、水酸基両末端ポリブタジエンとともに、ポリプロピレングリコール（ＰＰＧ）、ポリテトラメチレンエーテルグリコール（ＰＴＭＥＧ）等を併用しても差し支えない。
【００２１】
上記ウレタン系バインダー（Ｃ成分）の配合量は、上記弾性骨材（Ａ成分）と硬質骨材（Ｂ成分）とウレタン系バインダー（Ｃ成分）の合計量全体の５〜３０重量％の範囲内に設定することが好ましく、特に好ましくは１５〜２５重量％の範囲内である。すなわち、上記ウレタン系バインダー（Ｃ成分）の配合量が５重量％未満であると、弾性舗装材の強度が低下する傾向がみられ、逆に、上記ウレタン系バインダー（Ｃ成分）の配合量が３０重量％を超えると、加工性、作業性が悪化する傾向がみられるからである。
【００２２】
なお、本発明においては、上記特定のウレタン系バインダー（Ｃ成分）とともに、ウレタン系以外のバインダー、例えば、エポキシ系やアスファルト系等のバインダーを併用しても差し支えない。
【００２３】
本発明の弾性舗装材は、例えば、つぎのようにして作製することができる。すなわち、上記弾性骨材（Ａ成分）と、硬質骨材（Ｂ成分）と、ウレタン系バインダー（Ｃ成分）とを、所定の割合で攪拌機を用いて混合し、その混合物を金型に投入した後、金型を熱プレスにて所定の条件（例えば、１５０℃で２０分間）で加熱処理することにより、平板状（厚み２０〜５０ｍｍ）の弾性舗装材を作製することができる。ただし、成型方法、処理条件（温度および時間）については、これに限定されるものではない。
【００２４】
また、本発明の弾性舗装材は、上記弾性骨材（Ａ成分）と、硬質骨材（Ｂ成分）と、ウレタン系バインダー（Ｃ成分）とを混ぜ合わせ、これを路面に敷き詰めた後、熱ローラー等を用いて転圧成型することにより作製することも可能である。
【００２５】
本発明の弾性舗装材は、空隙率が３０〜５０％の範囲内が好ましく、特に好ましくは空隙率が３５〜４５％の範囲内である。
【００２６】
本発明の弾性舗装材１は、例えば、図１に示すように、地面４に設けたコンクリートあるいはアスファルトの路盤３に、エポキシ系あるいはウレタン系等の接着剤２を用いて接着することにより敷設され、排水性弾性舗装構造を形成することができる。ただし、敷設方法、接着方法、接着剤については特に限定するものではなく、先に述べたように、上記Ａ，Ｂ，Ｃの３成分を混合したものを路面に敷き詰めた後、熱ローラー等を用いて転圧成型することにより形成することもできる。
【００２７】
なお、本発明の弾性舗装材は、図１に示したような単層構造に限定されるものではなく、厚み方向に硬さの異なる層を積層してなる２層以上の多層構造であっても差し支えない。この場合、多層構造の表層（最上層）が、上記弾性骨材（Ａ成分）と、硬質骨材（Ｂ成分）と、特定のウレタン系バインダー（Ｃ成分）とを用いて成形されてなるものであることが好ましい。
【００２８】
本発明の弾性舗装材の用途としては、道路用のみに限定されるものではなく、例えば、遊歩道や競技場のフィールド等に使用することも可能である。
【００２９】
つぎに、実施例について比較例と併せて説明する。
【００３０】
まず、実施例および比較例に先立ち、ジエン含有量が異なる種々のウレタン系バインダーを合成した。すなわち、ポリオール成分として水酸基両末端ポリブタジエンを用い、これを芳香族系ポリイソシアネート成分であるＭＤＩと反応させた。そして、前記式（１）で表される水酸基両末端ポリブタジエン構造部分の含有量（ＰＢ含有量）が、バインダー全体の０、１２、２８、３３、４０、５０、６５、７５重量％であるウレタンプレポリマーをそれぞれ合成した。
【００３１】
【実施例１】
弾性骨材として、ひじき状ゴムチップ（平均太さ：０．５〜１．５ｍｍ、平均長さ：３〜１０ｍｍ）１００重量部（以下「部」と略す）と、硬質骨材である珪砂（平均粒径：２５０μｍ）４０部と、ウレタン系バインダーであるＭＤＩ系ウレタンプレポリマー（ＰＢ含有量：５０重量％）４０部とを配合して攪拌混合した後、混合物を所定の空隙率となるように計算し、金型に投入して１５０℃、２０分間の熱プレスにより、厚み３０ｍｍ、空隙率４２％の平板状の弾性舗装材を作製した。
【００３２】
【実施例２】
ＰＢ含有量が４０重量％であるＭＤＩ系ウレタンプレポリマーを用いる以外は、実施例１と同様にして、弾性舗装材を作製した。
【００３３】
【実施例３】
ＰＢ含有量が３３重量％であるＭＤＩ系ウレタンプレポリマーを用いる以外は、実施例１と同様にして、弾性舗装材を作製した。
【００３４】
【実施例４】
実施例１と同様の材料を用いて、表層（厚み８ｍｍ）を形成するとともに、硬質骨材を配合しない以外は、実施例１と同様の材料を用いて、下層（厚み２２ｍｍ）を形成し、表層と下層の２層構造からなる弾性舗装材を作製した。
【００３５】
【実施例５】
硬質骨材である珪砂（平均粒径：２５０μｍ）の配合割合を１５．６部に変更する以外は、実施例１と同様にして、弾性舗装材を作製した。
【００３６】
【実施例６】
硬質骨材である珪砂（平均粒径：２５０μｍ）の配合割合を６０部に変更する以外は、実施例１と同様にして、弾性舗装材を作製した。
【００３７】
【比較例１】
ＰＢ含有量が２８重量％であるＭＤＩ系ウレタンプレポリマーを用いる以外は、実施例１と同様にして、弾性舗装材を作製した。
【００３８】
【比較例２】
ＰＢ含有量が１２重量％であるＭＤＩ系ウレタンプレポリマーを用いる以外は、実施例１と同様にして、弾性舗装材を作製した。
【００３９】
【比較例３】
ポリオール成分としてＰＰＧを用い、ＰＢ含有量が０重量％であるＭＤＩ系ウレタンプレポリマーを用いる以外は、実施例１と同様にして、弾性舗装材を作製した。
【００４０】
【比較例４】
硬質骨材である珪砂を配合しない以外は、実施例１と同様にして、弾性舗装材を作製した。
【００４１】
【比較例５】
ＰＢ含有量が７５重量％であるＭＤＩ系ウレタンプレポリマーを用いる以外は、実施例１と同様にして、弾性舗装材を作製した。
【００４２】
【比較例６】
ＰＢ含有量が６５重量％であるＭＤＩ系ウレタンプレポリマーを用いる以外は、実施例１と同様にして、弾性舗装材を作製した。
【００４３】
このようにして得られた実施例品および比較例品の弾性舗装材を用いて、下記の基準に従い、各特性の評価を行った。これらの結果を、後記の表１〜表３に併せて示した。
【００４４】
〔密着性〕
弾性骨材（ゴムチップ）と、ウレタン系バインダーとの密着性を、以下のようにして評価した。すなわち、天然ゴム系ゴムシートを用い、ウレタン系バインダーで熱硬化により貼り合わせた後、剥離させるＴ字剥離試験に置き換えて、弾性骨材（ゴムチップ）と、ウレタン系バインダーとの密着性の評価を行った。評価は、母材破壊したものを○、母材破壊および界面剥離が混在したものを△、界面剥離したものを×とした。
【００４５】
〔硬質骨材の残量〕
上記各弾性舗装材を屋外曝露（６ヶ月および１年）し、ついでその表面にゴム片のテストピースを時速６０ｋｍ／ｈで１０回接触回転させて表面摩擦を行った後、弾性舗装材表面の硬質骨材の残量を、目視により観察した。評価は、硬質骨材の脱落がなく、初期状態と同じものを◎、硬質骨材の脱落がほとんどないものを○、硬質骨材がほとんど脱落したものを△、硬質骨材が脱落し、さらにバインダーまでもが摩耗されゴム表面が露出したものを×とした。
【００４６】
〔濡れ時のすべり摩擦係数（μｗｅｔ）〕
大きさ５０×５０ｃｍ、厚み３ｃｍの平板状試験片を作製し、常温で３日以上放置した後、試験片の表面に水を流しながら、ＤＦテスター（有限会社サニー工研製）を用いて、８０ｋｍ／ｈ以下の領域で濡れ時のすべり摩擦係数（μｗｅｔ）を、ＡＳＴＭ Ｅ１９１１−９８に準じて測定した。なお、濡れ時のすべり摩擦係数（μｗｅｔ）の測定は、屋外曝露（６ヶ月）した後、表面にゴム片のテストピースを時速６０ｋｍ／ｈで１０回接触回転させて表面摩擦を行ったものと、屋外曝露（１年）した後、表面にゴム片のテストピースを時速６０ｋｍ／ｈで１０回接触回転させて表面摩擦を行ったものと、屋外曝露も表面摩擦も行っていないもの（初期値）の、それぞれについて行った。
【００４７】
〔弾性舗装材の引張強さ〕
上記各弾性舗装材の表層部１０ｍｍを切り出し、ＪＩＳ Ｋ ６２５１に準じて、引張強さを測定した。
【００４８】
【表１】

【００４９】
【表２】

【００５０】
【表３】

【００５１】
上記結果から、実施例品はいずれも、弾性骨材とウレタン系バインダーとの密着性が良好で、硬質骨材の脱落もほとんどなく、高いすべり摩擦係数（μｗｅｔ）を長期間維持できることがわかる。
【００５２】
これに対して、比較例１品は、ウレタン系バインダー中のＰＢ含有量が２８重量％（３０重量％未満）であるため、弾性骨材とウレタン系バインダーとの密着性がやや劣り、硬質骨材がほとんど脱落するとともに、初期のすべり摩擦係数（μｗｅｔ）を長期間維持できないことがわかる。比較例２品は、ウレタン系バインダー中のＰＢ含有量が１２重量％（３０重量％未満）であるため、弾性骨材とウレタン系バインダーとの密着性が著しく劣り、硬質骨材が脱落してゴム表面が露出するとともに、初期のすべり摩擦係数（μｗｅｔ）を長期間維持できないことがわかる。比較例３品は、ウレタン系バインダー中のＰＢ含有量が０重量％（３０重量％未満）であるため、弾性骨材とウレタン系バインダーとの密着性が著しく劣り、硬質骨材が脱落してゴム表面が露出するとともに、初期のすべり摩擦係数（μｗｅｔ）を長期間維持できないことがわかる。比較例４品は、硬質骨材を配合していないため、初期のすべり摩擦係数（μｗｅｔ）が著しく低いことがわかる。比較例５品は、ウレタン系バインダー中のＰＢ含有量が７５重量％（７０重量％を超える）であるため、高いすべり摩擦係数（μｗｅｔ）を長時間維持できるが、強度が低下し、かつ作業性が悪化する。
【００５３】
【発明の効果】
以上のように、本発明の弾性舗装材は、弾性骨材（Ａ成分）と、硬質骨材（Ｂ成分）とを併用し、前記式（１）で表される水酸基両末端ポリブタジエン構造部分の含有量が、３０〜５０重量％の範囲内に設定されているウレタン系バインダー（Ｃ成分）を用いてなるものである。そのため、弾性骨材（Ａ成分）とウレタン系バインダー（Ｃ成分）との密着性が良好であり、弾性舗装材が長期間にわたって屋外に曝露されることによってウレタン系バインダー（Ｃ成分）が硬化しても、密着性が保持されており、高いすべり摩擦係数（μｗｅｔ）を長期間維持することができるという優れた効果を奏する。したがって、長期の屋外での車両走行において、雨天時のすべり摩擦係数（μｗｅｔ）の低下がほとんどなく、濡れた路面上において車両のスリップ発生を防止することができる。
【００５４】
また、前記式（１）で表される水酸基両末端ポリブタジエン構造部分の含有量を、３０〜５０重量％の範囲内に設定しているため、強度、作業性等のバランスのとれた弾性舗装材となる。
【００５５】
そして、上記硬質骨材（Ｂ成分）の配合量を、弾性骨材（Ａ成分）と硬質骨材（Ｂ成分）とウレタン系バインダー（Ｃ成分）の合計量全体の５〜３５重量％の範囲内に設定すると、濡れ時のすべり摩擦係数（μｗｅｔ）が高く、強度の低下もない弾性舗装材となる。
【図面の簡単な説明】
【図１】 本発明の弾性舗装材を用いた弾性舗装構造を示す断面図である。
【符号の説明】
１ 弾性舗装材
２ 接着剤
３ 路盤
４ 地面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an elastic pavement in which an elastic aggregate and a resin binder are mixed and laid on a roadbed (especially a roadway) or the like to form an elastic pavement.
[0002]
[Prior art]
Conventional elastic pavement material is made by mixing resin binders such as urethane with elastic aggregates such as rubber chips obtained by pulverizing rubber products such as discarded tires of automobiles, molding into a mat shape, or laying on the road surface, It is formed by rolling using a heat roller or the like. In general, hard aggregates such as pebbles, sand, quartz sand, and glass are used in combination with elastic aggregates such as rubber chips for the purpose of preventing slippage on rainy days on ordinary roads.
[0003]
In addition, the resin binder that is a component of the elastic pavement material includes a urethane binder and an epoxy binder, which are used alone or in a blend, but generally a highly flexible urethane binder is used. (For example, refer to Patent Document 1). As a urethane-based binder, generally, both a one-component moisture curable type and a two-component curable type are used, and ether polyols such as PPG (polypropylene glycol) are mainly used as the polyol component. ing.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 3-200851
[Problems to be solved by the invention]
However, an ether urethane binder using an ether polyol such as PPG does not have sufficient adhesion to an elastic aggregate such as a rubber chip. In particular, when the elastic pavement is exposed to the outdoors for a long period of time, the binder is cured, and the adhesion with a rubber chip or the like is further deteriorated. In this way, when the vehicle passes through the elastic pavement with the adhesiveness between the binder and the rubber chip deteriorated, the tire tread and the elastic pavement rub against each other, and the binder is hardened from the rubber chip surface and accordingly hard. The aggregate is detached and the rubber surface is easily exposed. As a result, the sliding friction coefficient of the elastic pavement in a wet state is significantly lower than the value immediately after the molding, and the vehicle slips easily on the wet road surface. According to the Road Structure Ordinance, the sliding friction coefficient when wet in the rain is 0.33 or more at 60 km / h, and is 0.4 or more, more preferably 0.5 or more when considering safe driving. is there.
[0006]
The present invention has been made in view of such circumstances. By increasing the adhesion between the urethane binder and the elastic aggregate, the binder from the surface of the elastic aggregate can be exposed to the outdoors for a long period of time. It is an object of the present invention to provide an elastic pavement in which the exposure of the surface of the elastic aggregate due to the separation of the hard aggregate or the hard aggregate is suppressed, and the decrease in the sliding friction coefficient of the elastic pavement in a wet state is suppressed.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the elastic pavement material of the present invention has a configuration in which it is formed using the following (A) to (C).
(A) Elastic aggregate.
(B) Hard aggregate.
(C) A urethane-based binder obtained by reacting a polyol component mainly composed of hydroxyl-terminated polybutadiene and an aromatic polyisocyanate component, wherein the hydroxyl-terminated polybutadiene represented by the following formula (1) content of the structural parts, it is configured in the range of 3 0-5 0% by weight.
[Expression 2]

[0008]
That is, the present inventors conducted extensive research to obtain an elastic pavement that has good adhesion between the urethane binder and the elastic aggregate and can maintain a high sliding friction coefficient (μwet) for a long period of time. The first focuses on a urethane-based binder, the results of extensive studies about its polyol component, the polyol component, the use of hydroxyl both ends polybut diene down, adhesion between the urethane binder and the elastic aggregate enhances I found out. The reason is, the hydroxyl group at both ends polybut diene emissions molecular skeleton, a molecular skeleton of the polybutadiene and natural rubber used in the rubber materials such as tires, the same or to similar, i.e. the polarity of both near , the compatibility is high, familiar with the hydroxyl groups at both ends polybut diene emissions and rubber material or the like, the wettability is improved, presumably due to the adhesion is high. As a result of extensive research for the ratio to the total weight of the hydroxyl groups at both terminals polybut diene down urethane binder, the content of hydroxyl groups at both terminals polybut diene emission structure moiety represented by the above formula (1), 3 0 When 5 0 is set within a weight percent range, it found that the intended object can be achieved, thereby achieving the present invention. That is, the ratio to the total weight of the hydroxyl groups at both terminals polybut diene down urethane binder, is set to the predetermined range, it is possible to enhance the adhesion between the urethane binder and the elastic aggregate, an elastic pavement material for a long time Even if the binder is cured by being exposed to the outside, a decrease in adhesion with the elastic aggregate or the like is suppressed. Therefore, even if the vehicle passes through the elastic pavement, even if the tire tread and the surface of the elastic pavement are rubbed, the release of the binder and hard aggregate from the elastic aggregate surface is suppressed, and the elastic aggregate surface is exposed. Is suppressed. As a result, the sliding friction coefficient of the elastic pavement in a wet state is appropriately maintained, and the occurrence of vehicle slip on the wet road surface during rainfall can be prevented.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail.
[0010]
The elastic paving material of the present invention is formed using an elastic aggregate (component A), a hard aggregate (component B), and a specific urethane binder (component C).
[0011]
The elastic aggregate (component A) is not particularly limited, and rubber materials such as natural rubber and synthetic rubber, and synthetic resin materials having elasticity such as thermoplastic elastomer and foamed polyurethane are used in the form of elbows, granules, etc. What was pulverized into a chip shape is used. These may be used alone or in combination of two or more. The synthetic rubber is not particularly limited. For example, styrene-butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), ethylene-propylene-diene terpolymer (EPDM), butadiene rubber (BR), chloroprene rubber. (CR) and blended rubbers thereof. Among these, rubber chips made from waste tires are preferably used from the viewpoint of resource reuse. Other aggregates may be used in combination as necessary.
[0012]
The hard aggregate (component B) used together with the elastic aggregate (component A) is not limited to an inorganic material or an organic material, but as the inorganic material, crushed stone, silica sand, sand, silica, glass, etc. can be used as the organic material. Examples thereof include resin materials such as nylon and urethane. These may be used alone or in combination of two or more. Among these, crushed stone or quartz sand is preferably used in terms of availability and cost.
[0013]
The average particle diameter of the hard aggregate (component B) is preferably in the range of 0.01 to 2.5 mm, particularly preferably in the range of 0.01 to 0.5 mm. That is, when the average particle diameter of the hard aggregate (component B) is less than 0.01 mm, the workability of the elastic pavement tends to be deteriorated. This is because a large amount of addition is required because the friction coefficient is low.
[0014]
The amount of the hard aggregate (component B) is within the range of 5 to 35% by weight of the total amount of the elastic aggregate (component A), hard aggregate (component B) and urethane binder (component C). It is preferable to set to be in the range of 15 to 30% by weight. That is, when the amount of the hard aggregate (component B) is less than 5% by weight, the sliding friction coefficient (μwet) at the time of wetting tends to be too small, and conversely, the hard aggregate (component B) It is because the tendency for the intensity | strength of elastic pavement to fall will be seen when the compounding quantity of exceeds 35 weight%.
[0015]
As the elastic aggregates (A component) and the hard aggregates urethane binder component (C) used together with component (B), for example, a hydroxyl group at both terminals polybut diene down of the polyol component, an aromatic polyisocyanate component Examples thereof include urethane prepolymers obtained by reaction.
[0016]
The aromatic polyisocyanate component used together with the polyol component is not particularly limited. For example, 4,4′-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate (2,4-TDI), 2, 6-tolylene diisocyanate (2,6-TDI), 3,3′-vitrylene-4,4′-diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, 2,4-tolylene diisocyanate urea Chijinjion (dimer of 2,4-TDI), 1,5- naphthylene diisocyanate, meta-phenylene diisocyanate, mosquitoes carbodiimide-modified MDI, ortho-toluidine diisocyanate, xylene diisocyanate, paraphenylene diisocyanate, such as isocyanate Natick, tri phenyl Tan-4,4 ', 4 "-. Triisocyanate triisocyanates such as polymeric MDI, which may be used either alone or in combination.
[0017]
As the urethane binder component (C), the content of hydroxyl groups at both terminals polybut diene emission structure moiety represented by the formula (1) (diene content) in the range of 3 0-5 0 wt% it is necessary to use those that are set. That is, when the diene content is less than 30 wt%, the adhesion between the elastic aggregates (A component) and worsening of such rubber chips, the diene content conversely exceeds 5 0% by weight, of the elastic pavement material This is because the strength decreases . Na us, and the weight of the polyol component composed mainly of hydroxyl group at both terminals polybutadiene, usually the weight of the hydroxyl terminated polybut diene down, as will be described later, together with the hydroxyl group at both ends polybut diene emissions, polypropylene glycol (PPG ) Or polytetramethylene ether glycol (PTMEG), the total weight of these is the weight of the polyol component.
[0018]
[Equation 3]

[0019]
The diene content is set within a specific range urethane binder component (C) has a hydroxyl group at both terminals polybut diene down a polyol component, an aromatic polyisocyanate component, by weight, a hydroxyl group at both ends polybut diene emissions / aromatic polyisocyanate component = 30/5 were blended in the range of 0-5 0/30 can be obtained by synthesizing the prepolymer.
[0020]
Incidentally, the urethane binder component (C), if any hydroxyl group content both ends polybut diene structure portion within a predetermined range, as the polyol component, the hydroxyl group at both terminals polybut diene ting together, polypropylene glycol (PPG), Polytetramethylene ether glycol (PTMEG) or the like may be used in combination.
[0021]
The blending amount of the urethane binder (C component) is in the range of 5 to 30% by weight of the total amount of the elastic aggregate (component A), hard aggregate (component B) and urethane binder (component C). It is preferable to set it to be within a range of 15 to 25% by weight. That is, when the blending amount of the urethane binder (C component) is less than 5% by weight, the strength of the elastic pavement tends to decrease, and conversely, the blending amount of the urethane binder (C component) is low. This is because when it exceeds 30% by weight, workability and workability tend to deteriorate.
[0022]
In the present invention, a binder other than urethane, for example, an epoxy or asphalt binder may be used in combination with the specific urethane binder (component C).
[0023]
The elastic pavement material of the present invention can be produced, for example, as follows. That is, the elastic aggregate (component A), hard aggregate (component B), and urethane-based binder (component C) were mixed at a predetermined ratio using a stirrer, and the mixture was put into a mold. Then, a plate-shaped (20-50 mm thick) elastic pavement material can be produced by heat-processing a metal mold | die on predetermined conditions (for example, 150 degreeC for 20 minutes). However, the molding method and processing conditions (temperature and time) are not limited thereto.
[0024]
The elastic pavement of the present invention is a mixture of the above-mentioned elastic aggregate (component A), hard aggregate (component B), and urethane binder (component C), which is spread on the road surface, It can also be produced by rolling using a roller or the like.
[0025]
The elastic pavement material of the present invention preferably has a porosity of 30 to 50%, particularly preferably a porosity of 35 to 45%.
[0026]
The elastic pavement material 1 of the present invention is laid, for example, by adhering to a concrete or asphalt roadbed 3 provided on the ground 4 by using an epoxy or urethane adhesive 2 as shown in FIG. A drainable elastic pavement structure can be formed. However, the laying method, the bonding method, and the adhesive are not particularly limited. As described above, after laying a mixture of the above three components A, B, and C on the road surface, It can also be formed by rolling and molding.
[0027]
The elastic paving material of the present invention is not limited to the single layer structure as shown in FIG. 1, but has a multilayer structure of two or more layers formed by laminating layers having different hardness in the thickness direction. There is no problem. In this case, the surface layer (uppermost layer) of the multilayer structure is formed using the elastic aggregate (component A), the hard aggregate (component B), and a specific urethane-based binder (component C). It is preferable that
[0028]
The use of the elastic pavement material of the present invention is not limited to road use, and can be used for, for example, a promenade or a stadium field.
[0029]
Next, examples will be described together with comparative examples.
[0030]
First, prior to Examples and Comparative Examples, various urethane binders having different diene contents were synthesized. That is, hydroxyl group-terminated polybutadiene was used as a polyol component, and this was reacted with MDI, which is an aromatic polyisocyanate component. Then, the content of hydroxyl groups at both terminals polybutadiene emission structure moiety represented by the formula (1) (PB content), in 0,12,28,33,40,50,65,75% by weight of the total binder Each urethane prepolymer was synthesized.
[0031]
[Example 1]
As elastic aggregates, hijiki rubber chips (average thickness: 0.5 to 1.5 mm, average length: 3 to 10 mm) 100 parts by weight (hereinafter abbreviated as “parts”) and silica sand (average) 40 parts of particle size: 250 μm) and 40 parts of MDI-based urethane prepolymer (PB content: 50% by weight), which is a urethane-based binder, are mixed with stirring, and then the mixture has a predetermined porosity. The flat elastic pavement material having a thickness of 30 mm and a porosity of 42% was prepared by calculation and charging into a mold and hot pressing at 150 ° C. for 20 minutes.
[0032]
[Example 2]
An elastic paving material was produced in the same manner as in Example 1 except that an MDI urethane prepolymer having a PB content of 40% by weight was used.
[0033]
[Example 3]
An elastic paving material was produced in the same manner as in Example 1 except that an MDI urethane prepolymer having a PB content of 33% by weight was used.
[0034]
[Example 4 ]
Using the same material as in Example 1, the surface layer (thickness 8 mm) is formed, and the lower layer (thickness 22 mm) is formed using the same material as in Example 1 except that the hard aggregate is not blended. An elastic pavement material having a two-layer structure of a surface layer and a lower layer was produced.
[0035]
[Example 5 ]
An elastic pavement was produced in the same manner as in Example 1 except that the blending ratio of silica sand (average particle size: 250 μm), which is a hard aggregate, was changed to 15.6 parts.
[0036]
[Example 6 ]
An elastic pavement was produced in the same manner as in Example 1 except that the mixing ratio of silica sand (average particle size: 250 μm), which is a hard aggregate, was changed to 60 parts.
[0037]
[Comparative Example 1]
An elastic pavement was produced in the same manner as in Example 1 except that an MDI urethane prepolymer having a PB content of 28% by weight was used.
[0038]
[Comparative Example 2]
An elastic paving material was produced in the same manner as in Example 1 except that an MDI urethane prepolymer having a PB content of 12% by weight was used.
[0039]
[Comparative Example 3]
An elastic pavement was produced in the same manner as in Example 1 except that PPG was used as the polyol component and an MDI urethane prepolymer having a PB content of 0% by weight was used.
[0040]
[Comparative Example 4]
An elastic pavement was produced in the same manner as in Example 1 except that silica sand, which is a hard aggregate, was not blended.
[0041]
[Comparative Example 5]
An elastic paving material was produced in the same manner as in Example 1 except that an MDI urethane prepolymer having a PB content of 75% by weight was used.
[0042]
[Comparative Example 6]
An elastic paving material was produced in the same manner as in Example 1 except that an MDI urethane prepolymer having a PB content of 65% by weight was used.
[0043]
Using the elastic paving materials of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. These results are shown in Tables 1 to 3 below.
[0044]
[Adhesion]
The adhesion between the elastic aggregate (rubber chip) and the urethane binder was evaluated as follows. That is, using a natural rubber-based rubber sheet, after bonding by thermosetting with a urethane-based binder, it is replaced with a T-shaped peeling test to evaluate the adhesion between the elastic aggregate (rubber chip) and the urethane-based binder. went. In the evaluation, “◯” indicates that the base material was destroyed, “Δ” indicates that the base material destruction and interfacial peeling were mixed, and “x” indicates that the interfacial peeling occurred.
[0045]
[Remaining amount of hard aggregate]
Each of the above elastic pavement materials was exposed outdoors (6 months and 1 year), and then a rubber piece test piece was contacted and rotated 10 times at a speed of 60 km / h on the surface for surface friction. The remaining amount of hard aggregate was visually observed. Evaluation is the same as in the initial state with no omission of hard aggregates, ◯ for those with little omission of hard aggregates, △ for those with almost no omission of hard aggregates, and hard aggregates omission, The case where even the binder was worn and the rubber surface was exposed was marked with x.
[0046]
[Sliding friction coefficient when wet (μwet)]
A flat test piece having a size of 50 × 50 cm and a thickness of 3 cm was prepared and allowed to stand at room temperature for 3 days or more. Then, while flowing water on the surface of the test piece, using a DF tester (manufactured by Sunny Koken Co., Ltd.), 80 km The sliding friction coefficient (μwet) at the time of wetting was measured according to ASTM E1911-98 in the region below / h. In addition, the measurement of the sliding friction coefficient (μwet) when wet was conducted after outdoor exposure (6 months), and surface friction was performed by rotating a test piece of rubber piece on the surface 10 times at a speed of 60 km / h. After the outdoor exposure (one year), the rubber piece test piece was contacted and rotated 10 times at a speed of 60 km / h on the surface, and the surface friction was applied. ) For each.
[0047]
[Tensile strength of elastic pavement]
A surface layer portion 10 mm of each elastic pavement was cut out, and the tensile strength was measured according to JIS K 6251.
[0048]
[Table 1]

[0049]
[Table 2]

[0050]
[Table 3]

[0051]
From the above results, it can be seen that all of the example products have good adhesion between the elastic aggregate and the urethane-based binder, hardly lose the hard aggregate, and can maintain a high sliding friction coefficient (μwet) for a long period of time.
[0052]
On the other hand, the product of Comparative Example 1 has a PB content of 28% by weight (less than 30% by weight) in the urethane binder, so the adhesion between the elastic aggregate and the urethane binder is slightly inferior, and hard bone It can be seen that the material almost falls off and the initial sliding friction coefficient (μwet) cannot be maintained for a long time. In Comparative Example 2, the PB content in the urethane binder is 12% by weight (less than 30% by weight), so the adhesiveness between the elastic aggregate and the urethane binder is remarkably inferior, and the hard aggregate falls off. It can be seen that the rubber surface is exposed and the initial sliding friction coefficient (μwet) cannot be maintained for a long time. In Comparative Example 3 product, the PB content in the urethane binder is 0% by weight (less than 30% by weight), so the adhesiveness between the elastic aggregate and the urethane binder is remarkably inferior, and the hard aggregate falls off. It can be seen that the rubber surface is exposed and the initial sliding friction coefficient (μwet) cannot be maintained for a long time. Since the comparative example 4 product does not contain hard aggregate, it can be seen that the initial sliding friction coefficient (μwet) is remarkably low. The product of Comparative Example 5 has a PB content in the urethane-based binder of 75% by weight (exceeding 70% by weight), so that a high sliding friction coefficient (μwet) can be maintained for a long time, but the strength decreases and the work Sex worsens.
[0053]
【The invention's effect】
As described above, the elastic pavement material of the present invention, the elastic aggregates (A component), a combination of the hard aggregates (B component), a hydroxyl group represented by the formula (1) at both ends polybut diene emission structure the content of concrete parts is obtained by using a 3 0-5 0% by weight of the urethane binder is in the range (C component). Therefore, the adhesion between the elastic aggregate (component A) and the urethane binder (component C) is good, and the urethane binder (component C) is cured by exposing the elastic pavement to the outdoors for a long period of time. However, the adhesiveness is maintained, and an excellent effect that a high sliding friction coefficient (μwet) can be maintained for a long time is obtained. Therefore, when the vehicle travels outdoors for a long time, there is almost no decrease in the sliding friction coefficient (μwet) during rainy weather, and it is possible to prevent the vehicle from slipping on a wet road surface.
[0054]
Further, the content of the formula (1) represented by a hydroxyl group at both terminals polybut diene emission structure part, because of the set in the range of 3 0 to 50% by weight, strength, balance of workability taken It becomes an elastic paving material.
[0055]
The amount of the hard aggregate (component B) is in the range of 5 to 35% by weight of the total amount of the elastic aggregate (component A), the hard aggregate (component B), and the urethane binder (component C). When set to the inside, an elastic pavement material having a high sliding friction coefficient (μwet) at the time of wetting and no reduction in strength is obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an elastic pavement structure using an elastic pavement material of the present invention.
[Explanation of symbols]
1 Elastic pavement material 2 Adhesive 3 Roadbed 4 Ground

Claims (4)

An elastic pavement formed by using the following (A) to (C).
(A) Elastic aggregate.
(B) Hard aggregate.
(C) A urethane-based binder obtained by reacting a polyol component mainly composed of hydroxyl-terminated polybutadiene and an aromatic polyisocyanate component, wherein the hydroxyl-terminated polybutadiene represented by the following formula (1) content of the structural parts, it is configured in the range of 3 0-5 0% by weight.

The elastic pavement material according to claim 1 , wherein the aromatic polyisocyanate component in (C) is 4,4'-diphenylmethane diisocyanate . The elastic pavement according to claim 1 or 2 , wherein the amount of the hard aggregate (B) is in the range of 5 to 35% by weight of the total amount of (A), (B) and (C). The elastic pavement according to any one of claims 1 to 3, which is a multi-layered elastic pavement, the uppermost layer of which is formed using the above (A) to (C).

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