JP3720107B2 - Thermal insulation foam and method for producing the same - Google Patents

Description

【００１３】
（式中 Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴は、水素原子または置換基である。また、上の式では、エポキシ化合物は三員環エーテルで示したが、四員環以上のものであってもよい。）
この反応は、２分子反応で、反応に関与する分子数が少なく、しかも二酸化炭素は気体で容易にエポキシ基のところまで移動できるので、樹脂中のような固体中でも反応が進みやすく好ましい。
また、上述のように、気泡内の二酸化炭素の分圧が揮発性発泡剤の蒸気圧より低くなっているために、熱伝導率が低く、良好な断熱性が得られる。また、揮発性発泡剤の蒸気圧が５ｍｍＨｇ以上あることから、真空断熱体に比較して空気の侵入による断熱性の悪化が抑えられる。
【００１４】
さらに、以下の式（１）を満足することがより好ましい。この理由は、次のとおりである。
すなわち、二酸化炭素が存在すると、熱伝導率は、簡単な近似式では式（２）に比例して大きくなる。水をあまり用いず従来のフロンを発泡剤に用いた断熱発泡体でも式（３）の関係にあるから、式（１）であれば、二酸化炭素の熱伝導率上昇への寄与は明らかに低くなる。
【００１５】
【数２】

【００１６】
以下に述べるように、本発明の断熱発泡体の製造方法によれば、イソシアネートの量を減らし、エポキシ化合物の量を増加させることによって、容易に上述の式（１）の関係を満たした断熱発泡体を得ることができる。
【００１７】
本発明の断熱発泡体では、上記のように二酸化炭素の固定化反応が進んで二酸化炭素の分圧が揮発性発泡剤の分圧よりも低くなった時点で、製造が完了したとされる。従って、本発明の断熱発泡体は、製造後、エポキシ基を含有する化合物と、前記エポキシ基が二酸化炭素と反応して生成した環状カーボネートとが存在し、経時的に前記反応がさらに進行して二酸化炭素とエポキシ基の濃度が減少するとともに、環状カーボネートが増加していく場合がある。その場合は、断熱発泡体は経時的に断熱性が向上する。
【００１８】
本発明による断熱発泡体の製造方法は、揮発性発泡剤と反応性発泡剤とを含むポリウレタン原料を用いて、反応性発泡剤とポリイソシアネートとの反応から発生した二酸化炭素、および揮発性発泡剤によって、独立気泡内が満たされた発泡ウレタン樹脂組成物を形成させる混合・発泡工程と、これと並行して進む独立気泡内の二酸化炭素と樹脂組成物中のエポキシ化合物との反応による二酸化炭素の固定工程とからなるのが特徴である。この方法によると、断熱発泡体は、通常のウレタン樹脂発泡体が形成されるのに必要な時間、すなわち数分から数十分で製造され、その発泡成形が終了後、気泡内の二酸化炭素の分圧が揮発性発泡剤の分圧以下になったところで製造が完了する。しかし、必ずしも二酸化炭素の固定が終了しているわけではなく、製造後も二酸化炭素の固定化反応が続き、二酸化炭素量の減少が進行する場合がある。二酸化炭素は、気体状態から樹脂中のエポキシ化合物と反応し、その反応は二酸化炭素濃度の高い気泡の内表面付近で進行するから、気泡の内表面近傍から環状カーボネートが形成される。
【００１９】
ここに用いられる揮発性発泡剤は、沸点１５０℃以下、分子量７０以上のもので、得られる断熱発泡体の独立気泡内における揮発性発泡剤の蒸気圧は、その沸点１５０℃以下であるために５ｍｍＨｇ以上が確保される。
本発明の断熱発泡体では、気泡内の二酸化炭素分圧が真空断熱体のように１ｍｍＨｇ以下になる必要はない。水発泡で真空断熱を達成するためには、気泡内の二酸化炭素分圧を少なくとも１ｍｍＨｇ以下にしなければ、熱伝導率の減少は期待できない。一方、本発明の断熱発泡体では、分圧が１ｍｍＨｇ以下に減少するまで二酸化炭素を固定しなくても、揮発性発泡剤に対する二酸化炭素の分圧比が減少するに応じて熱伝導率が低下する。従って、用いるエポキシ化合物の量が少なくても熱伝導率低減の効果が得られる。
【００２０】
また、本発明の主な狙いは、発泡性の悪い発泡剤を水などの反応性発泡剤と併用して良好な発泡体を得ることと、反応性発泡剤から発生した二酸化炭素を固定することにより熱伝導率の上昇を抑えることにある。従って、発泡性を大きく改善することは、多量に発生する二酸化炭素を固定しなければならないことを意味する。従って、発泡性と二酸化炭素の固定の両方を満足する、最適な揮発性発泡剤の沸点と反応性発泡剤の量の範囲が存在することになる。
沸点が４０℃より低い揮発性発泡剤は、もともと反応性発泡剤を併用するまでもなく良好な発泡が可能であるから、本発明を適用する効果が小さい。また、高沸点の揮発性発泡剤は、蒸気圧が小さいため、その熱伝導率が、残存している二酸化炭素分圧の影響を受けやすい。これらの理由から、２５℃における蒸気圧が５０ｍｍＨｇ程度以上ある沸点１００℃以下の揮発性発泡剤が使用されることが好ましい。さらに、沸点が６０℃を越える揮発性発泡剤は、反応性発泡剤として水を用いると、発泡性を改善するために必要な水の量が増加し、同時に必要なエポキシ化合物の量も増加する。従って、比較的発泡性が良い沸点４０〜６０℃の揮発性発泡剤を用い、ポリオール１００重量部に対して０．５重量部以上１．５重量部未満と比較的少量の水を反応性発泡剤として使用するのが、エポキシ化合物の量も減らせるのでコスト面からも、最も適している。
【００２１】
反応性発泡剤である水の使用量がポリオール１００ｇに対し１．５ｇであるとき、水とポリイソシアネートとの反応により発生する二酸化炭素量は１．５／１８モルである。また、ポリオール１００ｇとポリイシシアネート、揮発性発泡剤、エポキシ化合物、二酸化炭素固定化触媒など他の断熱発泡体の材料を合わせれば、全部の材料の重量は、通常ポリオール１００ｇ当たり２５０〜３００ｇ程度になる。従って、前記の水とポリイソシアネートとの反応により発生する二酸化炭素の量は、断熱発泡体１００ｇ当たり（１．５／１８）／（２５０／１００）＝０．３３モル以下となる。ただし、イソシアネート同士が反応してカルボジイミドを生成し、二酸化炭素を放出する反応も進行するため、実際の二酸化炭素発生量は、上記の値より少し大きくなる。しかし、多い場合でも、全体として０．０４０モル程度である。従って、これがすべてエポキシ基に付加してカーボネートになったとしても、断熱発泡体１００ｇ当たり０．０４０モルまでのカーボネートしか形成されない。カーボネートの存在は、これが樹脂成分とならない場合は、重量増加が単純に密度の増加となり、断熱発泡体の重量を重くする。従って、上記のように環状カーボネートの量が最小限に抑えられていることが好ましい。
【００２２】
沸点が４０℃より低い揮発性発泡剤については、既に述べたように添加する反応性発泡剤としての水の役割は相対的に低下し、製造上の観点からは、ポリオール１００重量部に対し０．５重量部程度の少量の添加で足りる。しかし、エポキシ化合物程度以上に高価なフッ素原子を有するハイドロフルオロカーボン（ＨＦＣ）のような化合物を揮発性発泡剤として用いる場合は、水の添加と発生する二酸化炭素の固定は、発泡性の改善以外に揮発性発泡剤の削減によるコストの削減と言う点で重要となってくる。従って、沸点４０℃以下の揮発性発泡剤を用いる場合でもそれが高価な場合には、例えばハイドロフルオロカーボン、とりわけ熱伝導率の観点から有利な１，１，１，３，３−ペンタフルオロプロパン等を揮発性発泡剤剤として用い、反応性発泡剤としての水をポリオール１００重量部に対し０．５部重量以上用いることにより、前記揮発性発泡剤の使用量を削減することが好ましい。
【００２３】
また、本発明の断熱発泡体の製造方法においては、反応性発泡剤とポリイソシアネートとの反応により発生する二酸化炭素の化学量論的なモル量に対して、１モル当量以上のエポキシ基を有する量のエポキシ化合物を用いることが好ましい。さらに、ポリイソシアネートがポリウレタン原料中にある水酸基のモル量に対して０．７〜１．１モル当量のＮＣＯ基を有することが特に好ましい。これは、以下の理由による。
ポリウレタン樹脂形成反応時に、エポキシ基とポリイソシアネートとの反応が進み、二酸化炭素と反応すべきエポキシ基が消費されてしまう。ここで、上述のように、エポキシ基の量を増やすこと、およびエポキシ基と副反応を起こすポリイソシアネートを減らすことが効果的となる。このような条件下では、副反応せずに残存するエポキシ基の量が十分あり、二酸化炭素の固定が円滑に進むのである。
【００２４】
ここで用いられるエポキシ化合物は、通常断熱発泡体を製造する雰囲気温度である１０℃以上３０℃以下の温度で液体であれば、ポリオールなどの他の材料への分散あるいは溶解が容易であるから、製造上の混合の操作が良好に進行する。その結果、二酸化炭素の固定も進みやすくなるので好ましい。
本発明の断熱発泡体は、発泡成形後において前記ポリウレタン樹脂組成物中に含まれるエポキシ化合物のエポキシ基、反応性発泡剤の反応により発生する二酸化炭素およびポリイソシアネートのイソシアネート基のモル濃度が、以下の式（４）を満足する関係にあることが好ましい。この関係を満たせば、エポキシ基がポリイソシアネートと反応して失われたり、特に発泡成形後にイソシアネート基同士が反応して新たに二酸化炭素が発生したりしても、二酸化炭素を固定する反応が継続的に進行し、二酸化炭素が減少する。
さらに、過剰のエポキシ基が存在して、式（５）の関係が満足される場合、より効率良く、より早く二酸化炭素の固定が進むため好ましい。
【００２５】
【数３】

【００２６】
しかし、式（５）左辺の不等号に対応するようにエポキシ基量が多くても、二酸化炭素の固定速度は飽和してくる上に、到達熱伝導率は低下しないため、エポキシ基増量に伴うコストの低減の観点からも、上式を満たすエポキシ基量が好ましい。また、ここで言う、エポキシ基濃度、二酸化炭素濃度、イソシアネート基濃度は一定の断熱発泡体中に存在するエポキシ基の数、気体状態の二酸化炭素分子の数、イソシアネート基の数のことであり、断熱発泡体からの溶媒による抽出液の液体クロマトグラムによる分析、断熱発泡体中の気体のガスクロマトグラムによる分析、あるいは断熱発泡体片の赤外吸収分析等によって把握できる。
【００２７】
このような条件は、以下のような本発明の好ましい製造方法をとることによって実現される。
製造時およびそれ以降の二酸化炭素の固定速度は、二酸化炭素固定化触媒の量を増やせば早くなる。しかし、二酸化炭素固定化触媒の中にはウレタン反応に活性を有するものが多いから、これを多く使用するとウレタン反応の制御が難しくなる。そこで、十分かつ最小限のエポキシ基量を確保することが重要になる。その上で、二酸化炭素固定化触媒の量を調節して、必要な二酸化炭素固定速度を実現すれば良い。
【００２８】
必要な二酸化炭素固定速度を実現するためのエポキシ基量として、本発明の断熱発泡体の製造方法では、反応性発泡剤である水から化学量論的に発生する二酸化炭素のモル量に対して２．５モル当量以上４モル当量以下のエポキシ基を有する量のエポキシ化合物を用いることが好ましい。２．５モル当量以上のエポキシ基を用いることにより、大部分の二酸化炭素が固定される。そして、エポキシ基の量を増やせば、二酸化炭素を固定する速度は増すが、４モル当量より多くを用いても、得られる発泡体の到達する熱伝導率はあまり変わらない。
このようなエポキシ量を用いることにより、ウレタン反応用触媒としてアミン触媒、二酸化炭素固定化触媒としてハロゲン化亜鉛とオニウム塩を用いる通常の処方でも、上記の式（４）と、式（５）の左辺が満たされたものができる。さらに、エポキシ化合物を、ポリイソシアネートと反応性発泡剤の水との反応から出る二酸化炭素のモル量に対して３．５から４モル当量用いれば、式（５）を満たすものが得られる。
【００２９】
本発明の断熱発泡体の製造方法に使用されるウレタン反応用触媒としては、エポキシ基とイソシアネートとの反応を促進させないという理由でジブチルチンラウレート等の有機錫触媒を用いることが好ましい。この場合、ウレタン反応用触媒として通常のアミン触媒を用いた場合に比べて、エポキシ基の残存量が増えるため、用いるエポキシ化合物の量も少なくて済む。また、同じエポキシ化合物量を用いた場合、二酸化炭素の固定に要する時間が短縮される。
また、泡化の遅い有機錫系の触媒に対して、泡化を早めるアミン触媒を添加したり、反応性発泡剤として水より泡化の早いギ酸を添加したりする方法等は、好ましいウレタン反応の調整法である。
【００３０】
さらに、過剰のエポキシ化合物の一部は、断熱発泡体の生成過程において、ポリイソシアネートとの反応や、ウレタン反応触媒の作用を受けたエポキシ開環反応によって、気泡膜や骨格を構成する樹脂成分の一部として取り込まれる。また、大部分の液体エポキシ化合物は、二酸化炭素を固定化する反応によって固体化されるため、収縮などの弊害が起こりにくい。
特に、１分子中に２〜４個のエポキシ基を有するエポキシ化合物は、断熱発泡体の生成過程において、ポリイソシアネートとの反応やウレタン反応触媒の作用を受けたエポキシ開環反応によって、気泡膜や骨格を構成する樹脂成分の一部として架橋構造を構成するため、ウレタン樹脂とエポキシ樹脂のハイブリッド構造を構成し、機械的強度が上昇する。
また、１分子中に１〜３個の水酸基を有するエポキシ化合物は、断熱発泡体の生成過程において、その水酸基とポリイソシアネートとの反応によって、気泡膜や骨格を構成する樹脂成分の一部として架橋構造を構成するため、ウレタン樹脂とエポキシ樹脂のハイブリッド構造を構成し、機械的強度が上昇する。
【００３１】
以上のように、本発明によれば、原料へ添加した反応性発泡剤が、ポリイソシアネートとの反応によって二酸化炭素を生成し、断熱発泡体の気泡形成に寄与することが可能になる。また、形成される断熱発泡体の気泡中の二酸化炭素は、エポキシ化合物により固定化される。これによって、断熱箱体へのポリウレタンフォームの充填性を向上させることが可能になるとともに、断熱発泡体の断熱性能を向上させ、機械強度をも向上させることができるのである。
１分子中に２〜４個のエポキシ基を有するエポキシ化合物としては、トリメチロールプロパンポリグリシジルエーテル、ネオペンチルグリコールジグリシジルエーテル、ビスフェノールＡ型エポキシ樹脂などが代表的なものである。
また、１分子中に１〜３個の水酸基を有するエポキシ化合物は、グリシドール、グリセロールポリグリシジルエーテル、ソルビトールポリグリシジルエーテルなどが代表的なものである。
【００３２】
本発明に用いられる気泡充填気体となる揮発性化合物としては、沸点が１５０℃以下で分子量が７０以上のものであれば、用いることは可能であるが、中でも以下の化合物が好ましい。
まず、環状炭化水素が断熱特性の向上のためには好ましい。この例として、環状炭化水素のシクロペンタン（分子量７０．１４）、シクロヘキサン（分子量８４．１６）、シクロヘキセン（分子量８２．１５）、１，４−シクロヘキサジエン（分子量８０．１３）、１，３−シクロヘキサジエン（分子量８０．１３）、クアドリサイクラン（分子量９２．１４）や芳香族化合物であるベンゼン（分子量７８．１１）、トルエン（分子量９２．１４）、チオフェン（分子量８４．１）、フルオロベンゼン（分子量９６．１）、クロロベンゼン（分子量１１３．５６）等が好適に用いられる。熱伝導率が空気等の不純物の影響を殆ど受けないようにするためには、室温における飽和蒸気圧が１００ｍｍＨｇ程度以上ある炭素数５〜６のものが最も適している。
他にも、熱伝導率の観点から、ピリミジン（分子量８０．０９）、ピラジン（分子量８０．０９）、ピリジン（分子量７９．１０）、テトラヒドロフラン（分子量７２．１１）、テトラヒドラピラン（分子量８６．１３）、１，３−ジオキソラン（分子量７４．１）、ジオキサン（分子量８８．１）、１，４−ジオキセン（分子量８６．１）、トリオキサン（分子量９０．０７）、チアゾ−ル（分子量８５．１２）、２−メトキシ−１，３−ジオキソラン（分子量１０４．１１）等がある。
【００３３】
また、熱伝導率低減の観点から、弗化物で分子量の大きい炭素数３〜７の高弗化あるいは全弗化した弗化炭化水素、炭素数３〜８の弗化エーテル、炭素数３〜６の弗化第３級アミンの蒸気が充填気体となる構成が特に好ましい。
高弗化あるいは全弗化した炭素数３〜１１の弗化炭化水素としては、直鎖状、分岐状、環状のものがある。例えば、１，１，１，４，４，４−ヘキサフルオロブタン（分子量１６６、沸点２４．６℃）、１，１，１，３，３−ペンタフルオロプロパン（分子量１３４、沸点１４℃）、１，１，２，２，３−ペンタフルオロプロパン（分子量１３４、沸点２６℃）、パーフルオロヘキサン（分子量３３８、沸点６０℃）、パーフルオロシクロヘキサン（分子量３００）、パーフルオロヘプタン（分子量３７０、沸点８０℃）、パーフルオロ（メチルシクロヘキサン）（分子量３５０、沸点７６℃）、パーフルオロ（メチルシクロペンタン）（分子量３００、沸点６０℃）、パーフルオロペンタン（分子量２８８、沸点２９．５℃）、パーフルオロシクロペンタン（分子量２５０）、パーフルオロイソペンタン（分子量２８８）、パーフルオロ−３−メチルブタン（分子量２８８）、パーフルオロ−２，２−ジメチルプロパン（分子量２８８）、パーフルオロイソヘキサン（分子量３３８）、パーフルオロ−３−メチルペンタン（分子量３３８）、パーフルオロ−２，２−ジメチルブタン（分子量３３８）、パーフルオロ−２，３−ジメチルブタン（分子量３３８）、パーフルオロジメチルシクロブタン（分子量３００）などが適用できる。また、大気中での寿命が短く地球温暖化への影響が小さいと考えられる高弗化炭化水素として、高弗化アルケンがあり、パ−フルオロ−２−メチル−２−ペンテン、パ−フルオロ−４−メチル−２−ペンテン、パ−フルオロ−２−ペンテン、（パ−フルオロブチル）エチレン、（パ−フルオロイソプロピル）エチレン、ヘキサフルオロプロペン、ヘキサフルオロ−１，３−ブタジエン、オクタフルオロ−２−ブテン、オクタフルオロシクペンテン、３，３，４，４，４−ペンタフルオロブテン−１、パ−フルオロヘプテン−１、パ−フルオロオクテン−１、１Ｈ，１Ｈ，２Ｈ−パ−フルオロ−１−オクテン、テトラフルオロエチレン等が適用できる。
【００３４】
また、高弗化あるいは全弗化した炭素数３〜８の弗化エーテルとしては、直鎖状、分岐状、環状などのものがある。例えば、２，２，３，３，３−ペンタフルオロプロピルメチルエーテル（分子量１６４、沸点４６℃）、２，２，３，３，３−ペンタフルオロプロピルー１，１，２，２−テトラフルオロエチルエーテル（分子量２５０、沸点５８℃）、１，１，２，２−テトラフルオロエチルメチルエーテル（分子量１３２、沸点３８℃）、１，１，３，３，３−ペンタフルオロ−２−トリフルオロメチルプロピルメチルエーテル（分子量２３２、沸点６８−７４℃）、パーフルオロジエチルエーテル（分子量２５４）、パーフルオロ−２−ブチルテトラヒドロフラン（分子量４１６、沸点９９−１０７℃）、１，１，２，３，３，３−ヘキサフルオロプロピルメチルエーテル（分子量１８０．０６、沸点５３℃）、２，２，２−トリフルオロエチルジフルオロメチルエーテル（分子量１５０．０４、沸点２９℃）などが適用できる。
また、高弗化あるいは全弗化した炭素数３〜６の弗化第３級アミンとしては、直鎖状、分岐状、環状のどの構造でも適用できる。例えば、パーフルオロトリエチルアミン（分子量３７１）、パーフルオロピリジン（分子量１６９、沸点８９℃）などが好適に用いられる。
【００３５】
さらに、以上に説明した製造方法においては、発泡成形を行う容器内の圧力を、真空ポンプを用いて制御することによって、気泡径を調整することもできる。常圧下での発泡成形の場合には、ポリウレタンの形成と発泡のタイミングは発泡剤の沸点で決められる。発泡剤の沸点が低くて発泡が早過ぎれば、樹脂が柔らかすぎるため気泡が大きくなる。一方、発泡剤の沸点が高すぎれば、ポリウレタン形成反応によっては発泡に必要な熱が得られないか、あるいは得られても発泡が遅くなって樹脂が固くなるために、充分な体積増加が起こらない。従って、室温程度から５０℃程度までの沸点を有する発泡剤しか用いられていない。これに対して、本発明の方法においては、発泡成形を行う容器内の減圧度を制御することによって、発泡時期を調整することができる。このため、ポリウレタン形成反応と発泡のタイミングを好適に決めることが可能になり、望ましい気泡径にして、断熱特性の優れた発泡体を容易に製造できる。また、沸点が高く熱伝導率の低い揮発性化合物の使用が可能になり、優れた断熱発泡体の製造が容易になる。好適な発泡のタイミングは、実験的に決定される。すなわち、真空ポンプによる減圧開始の時期と減圧の速度を変化させて、得られる発泡剤の気泡径を調べる。そして、気泡径が小さい場合には減圧時期を早めて減圧速度を速くし、気泡径が大きい場合には減圧時期を遅らせて減圧速度を遅くする。
【００３６】
また、このように発泡成形を行う容器内の圧力を減圧して発泡させると、必要な反応性発泡剤の量が少量で足りるため、反応性発泡剤の固定化に要する時間が短時間で済む。したがって、仮に反応性発泡剤が可燃性であっても、使用量が少ないために、製造工程における安全性は高い。
また、空気等の不純物を除いておくことは、高い断熱性の発泡体を得るという観点から望ましい。特に、独立気泡内の揮発性化合物の蒸気圧が低くなると、不純物の影響が大きくなるため、これを除く操作が重要となる。空気等の不純物を除くには、真空ポンプ等で減圧にすることによっても可能である。しかし、より完全に除くためには、発泡させる容器内を特定の気体で置換し、さらにポリウレタン原料を特定の気体でバブリングするか、バブリングと真空ポンプによる減圧除去を繰返すのがよい。用いる特定の気体は、安全性の面から難燃性であり、かつ微量残った場合に熱伝導率を高くしないように、熱伝導率の低いことが好ましい。このような気体として、クリプトン、キセノン等が適している。−３０〜２０℃の沸点を有する高弗化炭化水素も使用できる。高弗化炭化水素とは、大半の水素が弗素に置換された炭化水素のことである。これらの化合物は、沸点が低いので、冷却や圧縮により容易に回収が可能である。
【００３７】
また、上記容器内にウレタン原料を注入するにも、上記気体、特にクリプトン、キセノン、または二酸化炭素で加圧して注入するとよい。
発泡剤として働いた二酸化炭素は、二酸化炭素固定化触媒の作用により、エポキシ化合物と反応して環状カ−ボネ−トとなって固定化される。エポキシ化合物としては、各種のグリシジルエーテル、トリエチレンオキシド等がある。特にグリシジルエ−テルとしては、グリシド−ル、フェニルグリシジルエ−テル、ブチルグリシジルエ−テル、２−エチルヘキシルグリシジルエ−テル、２−メチルオクチルグリシジルエ−テル、グリセロ−ルジグリシジルエ−テル、グリセロ−ルトリグリシジルエ−テル、トリメチロ−ルプロパンポリグリシジルエ−テル、ネオペンチルグリコ−ルジグリシジルエ−テル、エチレングリコ−ルジグリシジルエ−テル等が用いられる。二酸化炭素固定化触媒としては、塩化亜鉛や臭化亜鉛、ヨウ化亜鉛等の金属ハロゲン化物と、アンモニウム塩、ホスホニウム塩、スルホニウム塩、オキソニウム塩、アルソニウム塩、スチボニウム塩、セレノニウム塩、ヨードニウム塩、スタンノニウム塩等のオニウム塩との組み合わせが用いられる。また、オニウム塩の中でもハロゲン化オニウムを用いることが好ましく、その中でもテトラブチルアンモニウムブロマイド、テトラブチルアンモニウムアイオダイド等のアンモニウムハライドやスルホニウムハライドが好ましい。その他、環状カ−ボネ−トの生成には、塩化リチウム、臭化リチウム、ヨウ化ナトリウム、ヨウ化リチウム等のアルカリ金属のハロゲン化物と前記オニウム塩を各々単独であるいは両者を併用したものも用いることができる。また、付加反応触媒は、ポリオール組成物あるいはイソシアネートのいずれに含有させてもよい。
【００３８】
【実施例】
以下に本発明の実施例を説明する。
図１は、以下の実施例により得た断熱箱体を示している。この断熱箱体１は、ＡＢＳ樹脂製の内箱２と鉄製の外箱３、および内箱２と外箱３によって形成される空間部に充填されたポリウレタンフォームからなる断熱発泡体４とから構成されている。
【００３９】
《実施例１》
ポリオール成分は、水酸基価４６０（ｍｇＫＯＨ／ｇ）の芳香族アミン系ポリエーテルポリオール１００重量部（以下単に部で表す）と、ウレタン反応用触媒（花王（株）製カオライザーＮｏ．１）２．０部と、整泡剤（信越化学（株）製シリコーン系界面活性剤Ｆ−３３５）１．５部と、反応性発泡剤としての水１．０部と、断熱発泡体のフリーブロー密度が２５〜２７（ｋｇ／ｍ³）になるように揮発性発泡剤シクロペンタンの配合部数を調製した混合液に、エポキシ化合物フェニルグリシジルエーテル１５部と、二酸化炭素固定化触媒の臭化テトラブチルアンモニウム／塩化亜鉛（１／１）１部との混合液を混合したものである。また、イソシアネート成分は、アミン当量１３５のジフェニルメタンジイソシアネート（以下クルードＭＤＩで表す）からなるポリイソシアネートである。
なお、フェニルグリシジルエーテル１５部は、反応性発泡剤である水１．０部とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対してエポキシ基が１．８モル当量含有する添加量に相当する。
このように調合したポリオール成分とイソシアネート成分とを、高圧発泡機を用いて、ポリオール成分の水酸基に対して０．９モル当量のＮＣＯ基が配合される混合比率で混合し、この発泡性原液を、内箱と外箱からなる箱体内部に注入し、発泡させた。こうして断熱発泡体の充填された断熱箱体を得た。
【００４０】
《比較例Ａ》
ポリオール成分とイソシアネート成分との配合比率を、ポリオール成分の水酸基に対して０．６５モル当量のＮＣＯ基が配合される比率にした他は実施例１と同じ処方とした。
【００４１】
《比較例Ｂ》
ポリオール成分とイソシアネート成分との配合比率を、ポリオール成分の水酸基に対して１．２モル当量のＮＣＯ基が配合される比率にした他は実施例１と同じ処方とした。
【００４２】
《比較例Ｃ》
実施例１のポリオール成分の中からエポキシ化合物１５部と、二酸化炭素固定化触媒１部を取り除き、二酸化炭素吸着剤ゼオライト（東ソー（株）製ゼオライト５Ａ）２５部をポリイソシアネート成分に混合した他は実施例１と同じ処方とした。
【００４３】
このようにして得られた断熱箱体を室温において４週間放置後、断熱発泡体を採取し、断熱発泡体の熱伝導率、コア密度、および圧縮強度を測定した。コア密度は、断熱発泡体の充填性を評価するためである。また、二酸化炭素の固定化の度合いを確認するため断熱発泡体に含まれるガスの組成を求めた。これらの結果を表１に示した。
【００４４】
【表１】

【００４５】
表中、ＣＰはシクロペンタンを表す（以下の表でも同じである。）。
表１から明らかなように、本実施例による断熱発泡体は、その独立気泡内部に残存する二酸化炭素の比率がきわめて少なく、優れた断熱性能を有する。
これは次の理由によるものと考えられる。
すなわち、ポリイソシアネートは、原料中の水酸基およびエポキシ化合物に対して反応活性を有するが、ポリイソシアネートとエポキシ化合物フェニルグリシジルエーテルとの反応は、ポリイソシアネートと水酸基との反応に比べ緩やかに進行する。さらに重要なことには、インデックスが０．９と小さいポリイソシアネートが少ないため、ポリイソシアネート中のＮＣＯ基の大半が水酸基と反応し、エポキシ基が消費される量は少なくなる。このため、断熱発泡体が形成された後の気泡内部に残存する二酸化炭素を反応固定化するために必要かつ十分なエポキシ基を残存することが可能となった。
【００４６】
また、フェニルグリシジルエーテルは、断熱発泡体の発泡過程では反応性発泡剤である水とポリイソシアネートとの反応による二酸化炭素の発生を阻害することはなく、生成する二酸化炭素を発泡剤として機能させることが可能になると共に、断熱発泡体の気泡内部に残存する二酸化炭素を有効に固定化することが可能となる。
また、反応性発泡剤の水とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対して１．８モル当量の過剰なエポキシ基を含有するフェニルグリシジルエーテルを用いることによって、断熱発泡体の生成過程においてウレタン反応触媒の作用を受けたエポキシ開環反応を生じても、気泡内部に残存する二酸化炭素を反応固定化するために必要なエポキシ基を残存することができる。さらに、フェニルグリシジルエーテルの一部は、断熱発泡体の生成過程においてポリイソシアネートとの反応によって、気泡膜や骨格を構成する樹脂成分の一部として架橋構造を構成し、断熱発泡体の機械強度を向上することとなる。
【００４７】
一方、比較例Ａでは、発泡過程で発生した二酸化炭素をほぼ完全に固定化でき、断熱発泡体の熱伝導率を低減することができた。しかし、断熱発泡体の機械強度が悪化し、断熱箱体の外観品質を著しく悪化させる結果となった。これは、ポリイソシアネートのＮＣＯ基の配合比率が、水酸基に対して過小であるため、未反応の水酸基が樹脂架橋を起こさず、機械強度を低下させたためと考えられる。
また、比較例Ｂでは、発泡過程で発生した二酸化炭素を十分に固定化できず、そのまま気泡内部に残存し、断熱発泡体の熱伝導率を低減することができなかった。これは、断熱発泡体の生成過程におけるエポキシ化合物とポリイソシアネートとの反応によって、二酸化炭素を固定化するに十分なエポキシ基が残存しなかったためと考えられる。
また、比較例Ｃでは、気泡内部に残存する二酸化炭素量は低減できたが、発泡効率が極めて悪かった。そのため、断熱発泡体は、密度が高く、ばらつきも大きい結果となり、箱体への充填性は極めて悪かった。また、得られた断熱発泡体の圧縮強度も著しく悪いものであった。
【００４８】
《実施例２》
二酸化炭素固定化触媒に臭化テトラブチルアンモニウム／臭化亜鉛（４／１）７部、ポリオール成分とイソシアネート成分との配合比率をポリオール成分の水酸基に対して１．０モル当量のＮＣＯ基が配合される混合比率にした他は実施例１と同じ処方とした。
発泡成形の５時間後、得られた断熱発泡体中のガスを分析したところ、シクロペンタンの分圧より二酸化炭素の分圧の方が低くなっており、製造は完了していた。得られた断熱箱体の１日後の熱伝導率は０．０１８５Ｗ／ｍｋで、７日後の熱伝導率は０．０１８０Ｗ／ｍｋまで低下した。これに応じて二酸化炭素は、その分圧が１１０ｍｍＨｇから７５ＨｇｍｍＨｇまで減少し、メタノールによる抽出液を液体クロマトグラムで分析して検出されるエポキシ基量は約２割減少し、それに相当するカーボネート量の増量が観測された。
【００４９】
また、上記製造工程において、箱体内を二酸化炭素で置換し、二酸化炭素雰囲気下で二酸化炭素の圧力により原料を箱体内へ注入し、発泡させたところ、製造後７日後には熱伝導率は０．０１７８Ｗ／ｍｋまで低下した。
このように、経時的な熱伝導率の減少と二酸化炭素、エポキシ基の減少、及びカーボネートの増加が観測されたのは、エポキシ基と二酸化炭素との反応が断熱発泡体中で続いているためと考えられる。
また、二酸化炭素雰囲気下で発泡することにより熱伝導率が向上したのは、常法に従い空気あるいは窒素の圧力で原料を注入し、空気あるいは窒素雰囲気で発泡を行うと、僅かに酸素あるいは窒素の断熱発泡体への混入があったためと考えられる。
【００５０】
《実施例３》
実施例２の原料組成で、エポキシ基の量を、反応性発泡剤である水とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対して２．６モル当量とし、他の条件は同じにして、断熱発泡体の充填されている断熱箱体を製造した。
発泡成形の後、１２時間後、ガス分析をしたところ、シクロペンタンの分圧は二酸化炭素の３倍以上あり、製造は完了していた。
得られた断熱発泡体の熱伝導率は、８日後で０．０１７５Ｗ／ｍｋであった。また、２週間後に熱伝導率の低下はほぼ止まり、０．０１７３Ｗ／ｍｋとなった。
また、発泡成形直後の断熱発泡体の試料片からメタノールによりエポキシ化合物を抽出し、液体クロマトグラフィーによりエポキシ基の濃度を測定した。同様に、断熱発泡体の試料片中に含まれる二酸化炭素濃度を測定した。また、ＩＲ測定によりＮＣＯ基の濃度を求めた。その結果、エポキシ基、二酸化炭素およびＮＣＯ基の濃度は、モル濃度で、式（６）の関係にあった。比較のために実施例１について同様の測定をしたところ、式（７）であった。
【００５１】
【数４】

【００５２】
このように、断熱発泡体の成形後早期に熱伝導率が下がったのは、上記のように、より過剰のエポキシ基が残存していることによると考えられる。
さらに、エポキシ基の量を、ポリイソシアネートと水の反応から発生する二酸化炭素の量に対して３．５モル当量、５モル当量と増やし、他の条件は同じにして断熱発泡体を作成した。
エポキシ基の量が３．５モル当量、および５モル当量のとき、製造後３日〜５日でほぼ一定の熱伝導率に到達したが、その値はともに０．０１７３Ｗ／ｍｋであった。そして、５モル当量まで増量しても３．５モル当量のときに比して大幅な熱伝導率の改善は達成できなかった。
なお、３．５モル当量、５モル当量の各々の場合発泡成形直後の発泡体中におけるエポキシ基、二酸化炭素およびイソシアネート基の濃度の関係は、エポキシ基の量が５モル当量の場合は式（８）、エポキシ基の量が３．５モル当量の場合は式（９）となっていた。５モル当量の場合、エポキシ基が大過剰に残っているために、エポキシ基の効果が飽和し、実質的には大幅な熱伝導率の改善がみられなかったと考えられる。
【００５３】
【数５】

【００５４】
《実施例４》
揮発性発泡剤としてシクロペンタンの代わりに１，１，１，３，３−ペンタフルオロプロパンを用い、反応性発泡剤である水の量を１．２部にした他は実施例３と同じにして、断熱発泡体を作製した。この断熱発泡体は、発泡成形の６日後には熱伝導率が０．０１７１Ｗ／ｍｋに達し、良好な断熱特性を有していた。また、水を反応性発泡剤として用いたので、揮発性発泡剤の使用量を削減できた。
【００５５】
《実施例５》
実施例３のエポキシ基量がポリイソシアネートと水との反応から発生する二酸化炭素に対して２．６モル当量用いた場合の原料組成で、ウレタン反応用触媒としてジブチルチンラウレート０．９部、二酸化炭素固定化触媒として臭化テトラブチルアンモニウム９部とし、他の条件は同じにして、断熱発泡体の充填されている断熱箱体を製造した。
得られた断熱発泡体の熱伝導率は、６日後で０．０１７５Ｗ／ｍｋに達した。また、断熱発泡体中のエポキシ基、二酸化炭素およびＮＣＯ基のモル濃度を測定した結果、式（１０）であった。
【００５６】
【数６】

【００５７】
このように、より早期に熱伝導率が下がったのは、ウレタン反応用触媒および二酸化炭素固定化触媒の作用をするものが、有機錫触媒のジブチルチンラウレートとオニウム塩の臭化テトラブチルアンモニウムの組み合わせにより、エポキシ化合物の副反応によるエポキシ基の損失が減少し、上記のように過剰のエポキシ基が残存していたことによると考えられる。
【００５８】
《実施例６》
エポキシ化合物として、ビスフェノールＡにエピクロルヒドリンを反応させて得られるジエポキサイド３０部を用いた他は実施例１と同じ処方とした。
なお、ジエポキサイド３０部は、水１．０部とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対してエポキシ基が１．６モル当量含有する添加量に相当する。
【００５９】
《比較例Ｄ》
ポリオール成分とイソシアネート成分との配合比率を、ポリオール成分の水酸基に対して０．６５モル当量のＮＣＯ基が配合される比率とした他は実施例６と同じ処方とした。
【００６０】
《比較例Ｅ》
ポリオール成分とイソシアネート成分との配合比率を、ポリオール成分の水酸基に対して１．２モル当量のＮＣＯ基が配合される比率とした他は実施例６と同じ処方とした。
【００６１】
《比較例Ｆ》
実施例６のポリオール成分からジエポキサイド３０部と二酸化炭素固定化触媒１部を取り除き、二酸化炭素吸着剤ゼオライト（東ソー（株）製ゼオライト５Ａ）２５部をポリイソシアネート成分に混合した他は実施例６と同じ処方とした。実施例６および比較例Ｄ、Ｅ、Ｆで得られた断熱箱体から発泡成形後４週間後に断熱発泡体を採取し、測定した特性を表２に示す。
【００６２】
【表２】

【００６３】
このように本実施例による断熱発泡体は、気泡内部に残存するガス成分中の二酸化炭素比率が少なく、優れた断熱性能を有する。
これは、エポキシ化合物ジエポキサイドが、二酸化炭素の固定化に有効に働き、しかもポリイソシアネートとの反応やエポキシ開環反応によって、気泡膜や骨格を構成する樹脂成分の一部として架橋構造を構成し、さらに二酸化炭素との固定化反応によって樹脂化もされたためである。
【００６４】
一方、比較例Ｄでは、発泡過程で発生した二酸化炭素をほぼ完全に固定化でき、断熱発泡体の熱伝導率を低減することができた。しかし、断熱発泡体の機械強度が低下し、断熱箱体の外観品質を著しく悪化させる結果となった。これは、比較例Ａと同様の理由によるものと考えられる。
また、比較例Ｅでは、発泡過程で発生した二酸化炭素を十分に固定化できず、そのまま気泡内部に残存し、断熱発泡体の熱伝導率を低減することができなかった。これは、比較例Ｂと同様の理由によるものと考えられる。
また、比較例Ｆでは、比較例Ｃと同様に発泡効率が極めて悪く、また、得られた断熱発泡体の圧縮強度も著しく低いものであった。
【００６５】
《実施例７》
エポキシ化合物として、グリセロールジグリシジルエーテル２０部を用いた他は実施例１と同じ処方とした。
なお、グリセロールジグリシジルエーテル２０部は、水１．０部とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対してエポキシ基が１．８モル当量含有する添加量に相当する。
【００６６】
《比較例Ｇ》
ポリオール成分とイソシアネート成分との配合比率を、ポリオール成分の水酸基に対して０．６５モル当量のＮＣＯ基が配合される比率とした他は実施例７と同じ処方とした。
【００６７】
《比較例Ｈ》
ポリオール成分とイソシアネート成分との配合比率を、ポリオール成分の水酸基に対して１．２モル当量のＮＣＯ基が配合される比率とした他は実施例７と同じ処方とした。
【００６８】
《比較例Ｉ》
実施例７のポリオール成分からグリセロールジグリシジルエーテル２０部と、二酸化炭素固定化触媒１部を取り除き、二酸化炭素吸着剤ゼオライト（東ソー（株）製ゼオライト５Ａ）２５部をポリイソシアネート成分に混合した他は実施例７と同じ処方とした。
実施例７および比較例Ｇ、Ｈ、Ｉで得られた断熱箱体から発泡成形後４週間後に断熱発泡体を採取し、測定した特性を表３に示す。
【００６９】
【表３】

【００７０】
このように本実施例による断熱発泡体は、気泡内部に残存するガス成分中の二酸化炭素比率を少なくし、優れた断熱性能を有する。
これは、エポキシ化合物グリセロールジグリシジルエーテルが、二酸化炭素の固定化に有効に働き、しかも樹脂成分の一部となったことによるものである。
比較例Ｇでは、発泡過程で発生した二酸化炭素をほぼ完全に固定化でき、断熱発泡体の熱伝導率を低減することができた。しかし、断熱発泡体の機械強度が低下し、断熱箱体の外観品質を著しく悪化させる結果となった。これは、比較例Ａと同様の理由によるものと考えられる。
また、比較例Ｈでは、発泡過程で発生した二酸化炭素を十分に固定化できず、そのまま気泡内部に残存し、断熱発泡体の熱伝導率を低減することができなかった。これは、比較例Ｂと同様の理由によるものと考えられる。
比較例Ｉでは、比較例Ｃと同様に発泡効率が極めて悪く、また、得られた断熱発泡体の圧縮強度も著しく低いものであった。
【００７１】
《実施例８》
ポリオール成分は、水酸基価４６０ｍｇＫＯＨ／ｇの芳香族アミン系ポリエーテルポリオール１００重量部と、ウレタン反応触媒（花王（株）製カオライザーＮｏ．１）２．０部と、整泡剤（信越化学（株）製シリコーン系界面活性剤Ｆ−３３５）１．５部と、反応性発泡剤の水１．０部と、断熱発泡体のフリーブロー密度が２５〜２７（ｋｇ／ｍ³）になるように揮発性発泡剤シクロペンタンの配合部数を調製した混合液に、エポキシ化合物フェニルグリシジルエーテル２５部と、二酸化炭素固定化触媒の臭化テトラブチルアンモニウム／塩化亜鉛（１／１）２部との混合液を混合したものである。また、イソシアネート成分は、アミン当量１３５のクルードＭＤＩから成るポリイソシアネートである。
なお、フェニルグリシジルエーテル２５部は、反応性発泡剤の水１．０部とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対してエポキシ基が４．０モル当量含有する添加量に相当する。
このように調合したポリオール成分とイソシアネート成分とを、高圧発泡機を用いて、ポリオール成分の水酸基に対して１．１５モル当量のＮＣＯ基が配合される混合比率で混合し、この発泡性原液を、内箱と外箱からなる箱体内部に注入し、発泡させた。こうして断熱発泡体の充填された断熱箱体を得た。
【００７２】
《比較例Ｊ》
フェニルグリシジルエーテルの配合部数を７．５部、すなわち、反応性発泡剤の水１．０部とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対して、エポキシ基が０．９モル当量を含有する割合とした他は実施例８と同じ処方とした。
【００７３】
《比較例Ｋ》
実施例７のポリオール成分からフェニルグリシジルエーテル２５部と、二酸化炭素固定化触媒２部を取り除き、二酸化炭素吸着剤ゼオライト（東ソー（株）製ゼオライト５Ａ）２５部をポリイソシアネート成分に混合した他は実施例８と同じ処方とした。
実施例８および比較例Ｊ、Ｋで得られた断熱箱体から発泡成形後３週間後に断熱発泡体を採取し、測定した特性を表４に示す。
【００７４】
【表４】

【００７５】
このように本実施例による断熱発泡体は、その気泡内部に残存する二酸化炭素の比率を少なくし、優れた断熱性能を有する。
これは、フェニルグリシジルエーテルが、水とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対して４．０モル当量の過剰なエポキシ基を含有することで、気泡内部に残存する二酸化炭素を有効に反応固定化することができたためと考えられる。
また、この断熱発泡体について、発泡直後に実施例３の方法に従って分析を行ったところ、式（６）が満足されており、十分な量のエポキシ基が残存していることが確認された。なお、このとき既に、二酸化炭素分圧は、シクロペンタン分圧よりも低くなっており、製造が完了していた。さらに、発泡成形１月後に同様の分析を行ったが、エポキシ基の残存が確認され、式（４）が満足されていた。
このとき、断熱発泡体中のガスを分析したところ、シクロペンタンの分圧が３６０ｍｍＨｇであり、シクロペンタンの分圧の方が二酸化炭素の分圧より高く、製造は完了していた。
また、フェニルグリシジルエーテルは、実施例１と同様に樹脂成分の一部となり、強度向上に寄与していると考えられる。
【００７６】
比較例Ｊでは、発泡過程で発生した二酸化炭素を十分に固定化できず、そのまま気泡内部に残存し、断熱発泡体の熱伝導率を低減することができなかった。これは、エポキシ化合物の量が不足したためと考えられる。
また、比較例Ｋでは、気泡内部に残存する二酸化炭素量はある程度低減できたが、発泡効率が極めて悪かった。このため、断熱発泡体は、密度が高く、ばらつきも大きく、箱体への充填性は極めて悪かった。また、得られた断熱発泡体の圧縮強度も著しく低いものであった。
【００７７】
また、上記実施例の断熱発泡体片からメタノールにより抽出した抽出物を液体クロマトグラムにより定量した。その結果、二酸化炭素がフェニルグリシジルエーテルに付加反応した生成物環状カーボネートの４ー（フェノキシメチル）ー１、３ージオキソランー２ーオンが断熱発泡体１００ｇ当たり０．０２５モル検出された。反応性発泡剤の水の使用量がポリオール１００ｇに対して１ｇと少なかったため、水とポリイシシアネートの反応から発生する二酸化炭素量も少量となり、生成するカーボネートも少量に抑えられた。
【００７８】
《実施例９》
エポキシ化合物として、ビスフェノールＡにエピクロルヒドリンを反応させて得られるジエポキサイド５０部を用いた他は実施例８と同じ処方とした。
なお、ジエポキサイド５０部は、水１．０部とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対してエポキシ基が２．６モル当量含有する添加量に相当する。
【００７９】
《比較例Ｌ》
ジエポキサイドの配合部数を１７部、すなわち、水１．０部とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対して、エポキシ基が０．９モル当量を含有する割合とした他は実施例９と同じ処方とした。
【００８０】
《比較例Ｍ》
ポリオール成分からジエポキサイド５０部と、二酸化炭素固定化触媒２部を取り除き、二酸化炭素吸着剤ゼオライト（東ソー（株）製ゼオライト５Ａ）２５部をポリイソシアネート成分に混合した他は実施例９と同じ処方とした。
実施例９および比較例Ｌ、Ｍで得られた断熱箱体から発泡成形３週間後に断熱発泡体を採取し、測定した特性を表５に示す。
【００８１】
【表５】

【００８２】
本実施例による断熱発泡体は、気泡内部に残存する二酸化炭素の比率はきわめて低く、優れた断熱性能を有する。また、十分な圧縮強度を有する。
比較例Ｌでは、発泡過程で発生した二酸化炭素を十分に固定化できず、そのまま気泡内部に残存し、断熱発泡体の熱伝導率を低減することができなかった。これは、比較例Ｊと同様の理由によるものと考えられる。
また、比較例Ｍでは、比較例Ｋと同様に発泡効率が極めて悪く、また、得られた断熱発泡体の圧縮強度も著しく低いものであった。
【００８３】
《実施例１０》
エポキシ化合物として、グリセロールジグリシジルエーテル３０部を用いた他は実施例８と同じ処方とした。
なお、グリセロールジグリシジルエーテル３０部は、水１．０部とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対してエポキシ基が２．６モル当量含有する添加量に相当する。
【００８４】
《比較例Ｎ》
グリセロールジグリシジルエーテルの配合部数を１０部、すなわち、水１．０部とポリイソシアネートとの反応によって発生する二酸化炭素のモル量に対して、エポキシ基が０．９モル当量を含有する割合とした他は実施例１０と同じ処方とした。
【００８５】
《比較例Ｏ》
ポリオール成分からグリセロールジグリシジルエーテル３０部と、二酸化炭素固定化触媒２部を取り除き、二酸化炭素吸着剤ゼオライト（東ソー（株）製ゼオライト５Ａ）２５部をポリイソシアネート成分に混合した他は実施例１０と同じ処方とした。
【００８６】
実施例１０および比較例Ｌ、Ｍで得られた断熱箱体から発泡成形３週間後に断熱発泡体を採取し、測定した特性を表６に示す。
本実施例による断熱発泡体は、実施例８と同様優れた断熱性能と十分な圧縮強度を有する。
比較例Ｎでは、発泡過程で発生した二酸化炭素を十分に固定化できず、そのまま気泡内部に残存し、断熱発泡体の熱伝導率を低減することができなかった。これは、比較例Ｌと同様の理由によるものと考えられる。
また、比較例Ｏでは、比較例Ｋと同様に発泡効率が極めて悪く、また、得られた断熱発泡体の圧縮強度も著しく低いものであった。
【００８７】
【表６】

【００８８】
【発明の効果】
以上のように本発明によれば、オゾン層破壊や地球温暖化などの地球環境問題への負荷が小さい発泡剤を用いた断熱性の優れた断熱発泡体が得られる。また、本発明によれば、そのような優れた断熱発泡体を単純な製造プロセスで作製することができる。
【図面の簡単な説明】
【図１】本発明の一実施例における断熱箱体の一部を切り欠いた斜視図である。
【符号の説明】
１ 断熱箱体
２ 内箱
３ 外箱
４ 断熱発泡体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat insulating foam used for a refrigerator, a freezer compartment, and the like and a method for producing the same.
[0002]
[Prior art]
In recent years, environmental destruction caused by chlorofluorocarbons such as ozone depletion or global warming has become a social problem, and the total elimination of specific chlorofluorocarbons such as trichloromonofluoromethane, which is a foaming agent for heat-insulating foams such as rigid urethane foam, has become a major issue. ing.
For this reason, for example, 1,1-dichloro-1-fluoroethane (HCFC-141b), 1,1-dichloro-2,2,2-trifluoroethane (HCFC-) which is a substance having a small ozone depletion coefficient as a foaming agent. 123) or the like is used to form a polyurethane foam.
In addition, a method for producing polyurethane foam using a hydrocarbon as a foaming agent, such as cyclopentane, which is less harmful to the environment such as destruction of the ozone layer or global warming, is well known (for example, a preliminary presentation of polyurethane international forum 93 in May 1993). 197 pages, Gerhard Heilich and Yoshinori Kihara "Pentane foamed rigid urethane foam"). However, pentane has a problem that it has a high boiling point and is slightly difficult to foam.
In addition to global environmental problems, the development of heat insulating foams using only water as a foaming agent is also progressing to solve flammability. However, since the thermal conductivity of carbon dioxide remaining in the bubbles is high, excellent heat insulation cannot be obtained.
[0003]
Therefore, if a hydrocarbon such as pentane and water are used together as a foaming agent, the foamability of the hydrocarbon can be improved. However, since a quantity of carbon dioxide comparable to that of hydrocarbons remains in the bubbles, there is a problem that high heat insulating properties cannot be obtained.
In addition, there is an attempt to realize vacuum insulation by making the inside of closed cells of the heat insulation foam into a vacuum by using water as a foaming agent and fixing the generated carbon dioxide by reacting with an epoxy compound (Japanese Patent Laid-Open No. 7-1990). 53757, 7-173314). However, in order to maintain the vacuum insulation, there is a problem that an extra step of forming an aluminum thin film or the like that completely prevents the intrusion of air from the outside is necessary.
[0004]
Conventionally, in order to improve the heat insulation performance of the heat insulating foam, attempts have been made to improve the radiant heat conductivity by reducing the diameter of the closed cells and efforts to reduce the carbon dioxide composition ratio in the closed cells.
For example, when hydrochlorofluorocarbon is used as a foaming agent, for example, there has been an attempt to improve the heat insulation performance of polyurethane foam by promoting the refinement of bubbles by adding fluorocarbon (JP-A-5-186629). Publication).
[0005]
Further, there has been a method in which a carbon dioxide adsorbent composed of zeolite or the like is previously contained in the foamable stock solution, and carbon dioxide inside closed cells is adsorbed to the adsorbent after the formation of the heat insulating foam.
However, carbon dioxide adsorbents such as zeolite adsorb moisture preferentially over carbon dioxide. For this reason, a part of the water added to the raw material to react with the polyisocyanate to generate carbon dioxide is adsorbed by the carbon dioxide adsorbent, thereby suppressing the generation of carbon dioxide. As a result, the amount of carbon dioxide generated that should contribute to the formation of bubbles in the heat-insulating foam is reduced, and the foaming efficiency of the heat-insulating foam is deteriorated. In addition, since the carbon dioxide adsorbent decreases the carbon dioxide adsorption capacity by adsorbing water, the proportion of carbon dioxide remaining in the bubbles increases.
As described above, in the production of the heat insulation box, the productivity is remarkably impaired and the reliability of the heat insulation performance is deteriorated, such as an increase in the filling amount of the heat insulation foam and defective products due to unfilling.
[0006]
[Problems to be solved by the invention]
As described above, if only hydrocarbons or water that have a low impact on global environmental problems such as ozone depletion and global warming are used as foaming agents, those that satisfy the high heat insulation properties of heat insulating foams are not a simple manufacturing process. There is a problem that it cannot be obtained.
An object of this invention is to provide the heat insulation foam excellent in the heat insulation characteristic, considering the load reduction to global environment.
Another object of the present invention is to provide a method for producing a heat-insulating foam having excellent heat insulation properties by a simple production process.
[0007]
[Means for Solving the Problems]
The heat-insulating foam of the present invention is composed of a foamed polyurethane resin composition having closed cells, and inside the closed cells, a vapor of a volatile compound having a boiling point of 150 ° C. or lower and a molecular weight of 70 or higher is 25 ° C. and a partial pressure of 5 mmHg or higher. Carbon dioxide is contained at a partial pressure lower than the partial pressure of the volatile compound, and at least the wall of the closed cell of the resin composition has an epoxy group of carbon dioxide in the presence of a carbon dioxide fixing catalyst. A solid or liquid cyclic carbonate compound as an addition reaction product.
[0008]
Moreover, the manufacturing method of the heat insulating foam of the present invention includes polyisocyanate, polyol, foam stabilizer, urethane reaction catalyst, reactive foaming agent, volatile foaming agent having a boiling point of 150 ° C. or lower and a molecular weight of 70 or more, an epoxy compound, and A foamed polyurethane resin composition having closed cells containing carbon dioxide generated by the reaction of the reactive foaming agent and the polyisocyanate and the volatile foaming agent by mixing and foaming a raw material containing a carbon dioxide fixing catalyst. A mixing / foaming step to be formed, and the carbon dioxide is subjected to an addition reaction with an epoxy group of the epoxy compound in the presence of the carbon dioxide fixing catalyst to form a solid or liquid cyclic carbonate compound. The foam is substantially filled with the vapor of the volatile foaming agent, and the foam has a partial pressure of the steam of 25 mmHg or more at 25 ° C. A step.
[0009]
Here, the volatile compound or the volatile foaming agent preferably has a boiling point of 40 ° C. or more and 100 ° C. or less, and a partial pressure in the closed cell of 50 mmHg or more and 450 mmHg or less.
Moreover, it is preferable that the said epoxy compound is a liquid at the temperature of 10 to 30 degreeC.
In one embodiment of the present invention, the polyurethane resin composition after foam molding contains an epoxy compound, and the carbon dioxide in the closed cells reacts with the epoxy groups of the epoxy compound over time in the presence of a carbon dioxide fixing catalyst. Alternatively, a liquid cyclic carbonate compound is formed, and the epoxy group is decreased and the cyclic carbonate compound is increased.
In a preferred embodiment of the present invention, the polyisocyanate has 0.7 to 1.1 molar equivalents of NCO groups with respect to the molar amount of hydroxyl groups in the raw material.
In another preferred embodiment of the present invention, the epoxy compound has an epoxy group of 1 molar equivalent or more with respect to the molar amount of carbon dioxide generated by the reaction of the reactive foaming agent and the polyisocyanate.
In a preferred embodiment of the present invention, the epoxy compound has 2 to 4 epoxy groups in one molecule.
In another preferred embodiment of the present invention, the epoxy compound has 1 to 3 hydroxyl groups in one molecule.
In a preferred embodiment of the present invention, the reactive foaming agent is water, and the amount thereof is 0.5 part by weight or more and less than 1.5 parts by weight with respect to 100 parts by weight of the polyol.
In yet another preferred embodiment of the present invention, the epoxy compound contains 2.5 to 4 molar equivalents of an epoxy group with respect to the molar amount of carbon dioxide generated by the reaction of the reactive blowing agent and the polyisocyanate. Have.
In a preferred embodiment of the present invention, a combination of an organotin compound and an onium salt serves as the urethane reaction catalyst and the carbon dioxide fixing catalyst.
In another preferred embodiment of the present invention, the mixing / foaming step is performed in a container, and the injection of the polyurethane raw material into the container is at least one atmosphere selected from the group consisting of xenon, krypton, and carbon dioxide. Done under.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
First, the volatile compound thru | or volatile foaming agent and reactive foaming agent which are used for this invention are demonstrated.
Here, the foaming agents that are usually vaporized by heating, including those having a boiling point higher than usual, are referred to as volatile foaming agents. And what has a vapor pressure in the equilibrium state at room temperature and a part exists as gas irrespective of whether the stable phase at normal temperature is solid, liquid, or gas. Moreover, this volatile foaming agent can also be used in mixture of 2 or more types.
A reactive foaming agent is a foaming agent that has the action of generating carbon dioxide by its chemical reaction and then immobilizing it as a solid or liquid cyclic carbonate compound by a chemical reaction with an epoxy compound. Say. Here, it refers to water that mainly reacts with polyisocyanate to produce carbon dioxide, or lower carboxylic acids such as formic acid and acetic acid.
[0011]
Next, the present invention will be described based on more specific embodiments.
The heat insulation foam of this invention consists of a foaming urethane resin composition, The bubble consists of a closed cell, and has the following characteristics.
The adiabatic foam contains a solid or liquid cyclic carbonate as a product obtained by addition reaction of carbon dioxide with an epoxy group of an epoxy compound in the presence of a carbon dioxide fixing catalyst at least near the inner surface of the bubble. . And the volatile foaming agent in a bubble has a vapor pressure of 5 mmHg or more at 25 degreeC. The volatile foaming agent has a vapor pressure of about 5 mmHg or more at 25 ° C. and a boiling point of 150 ° C. or less, and has a thermal conductivity equal to or less than that of currently used cyclopentane. It has a molecular weight of 70 or more which is about the same or higher.
The reaction formula in which carbon dioxide is added to the epoxy group of the epoxy compound to produce a solid or liquid cyclic carbonate is shown below.
[0012]
[Chemical 1]

[0013]
(Where R ¹ , R ² , R ^Three , R ^Four Is a hydrogen atom or a substituent. In the above formula, the epoxy compound is shown as a three-membered ether, but it may be a four-membered ring or more. )
This reaction is a bimolecular reaction, and since the number of molecules involved in the reaction is small, and carbon dioxide can easily move to the epoxy group by gas, it is preferable that the reaction easily proceeds even in a solid such as a resin.
Further, as described above, since the partial pressure of carbon dioxide in the bubbles is lower than the vapor pressure of the volatile foaming agent, the thermal conductivity is low, and good heat insulation is obtained. Moreover, since the vapor pressure of a volatile foaming agent is 5 mmHg or more, the deterioration of the heat insulation property by the penetration | invasion of air is suppressed compared with a vacuum heat insulating body.
[0014]
Furthermore, it is more preferable to satisfy the following formula (1). The reason for this is as follows.
That is, when carbon dioxide is present, the thermal conductivity increases in proportion to the formula (2) in a simple approximate expression. Insulation foam using conventional chlorofluorocarbon as a foaming agent without much water is also in the relationship of formula (3), so if formula (1), the contribution to the increase in thermal conductivity of carbon dioxide is clearly low. Become.
[0015]
[Expression 2]

[0016]
As described below, according to the method for producing a heat-insulating foam of the present invention, the amount of isocyanate is reduced and the amount of epoxy compound is increased, so that the heat-insulating foam that easily satisfies the relationship of the above formula (1). You can get a body.
[0017]
In the heat-insulating foam of the present invention, it is assumed that the production is completed when the carbon dioxide immobilization reaction proceeds and the partial pressure of carbon dioxide becomes lower than the partial pressure of the volatile foaming agent. Therefore, the heat-insulating foam of the present invention contains, after production, a compound containing an epoxy group and a cyclic carbonate produced by the reaction of the epoxy group with carbon dioxide, and the reaction further proceeds with time. As the concentrations of carbon dioxide and epoxy groups decrease, cyclic carbonates may increase. In that case, the heat insulation property of the heat insulating foam improves with time.
[0018]
A method for producing a heat-insulating foam according to the present invention comprises using a polyurethane raw material containing a volatile foaming agent and a reactive foaming agent, carbon dioxide generated from the reaction between the reactive foaming agent and the polyisocyanate, and the volatile foaming agent. By the mixing / foaming process for forming a foamed urethane resin composition filled with closed cells, and the reaction of carbon dioxide in the closed cells and the epoxy compound in the resin composition that proceeds in parallel with this process. It is characterized by comprising a fixing step. According to this method, the heat insulating foam is produced in a time required for forming a normal urethane resin foam, that is, from several minutes to several tens of minutes. The production is completed when the pressure falls below the partial pressure of the volatile blowing agent. However, the fixation of carbon dioxide is not necessarily completed, and the carbon dioxide fixation reaction may continue after the production, and the amount of carbon dioxide may decrease. Carbon dioxide reacts with the epoxy compound in the resin from the gaseous state, and the reaction proceeds in the vicinity of the inner surface of the bubble having a high carbon dioxide concentration, so that cyclic carbonate is formed from the vicinity of the inner surface of the bubble.
[0019]
The volatile blowing agent used here has a boiling point of 150 ° C. or lower and a molecular weight of 70 or higher, and the vapor pressure of the volatile blowing agent in the closed cells of the heat insulating foam obtained is 150 ° C. or lower in boiling point. 5 mmHg or more is secured.
In the heat insulation foam of this invention, the carbon dioxide partial pressure in a bubble does not need to be 1 mmHg or less like a vacuum heat insulation. In order to achieve vacuum insulation by water foaming, a decrease in thermal conductivity cannot be expected unless the carbon dioxide partial pressure in the bubbles is at least 1 mmHg or less. On the other hand, in the heat insulating foam of the present invention, even if carbon dioxide is not fixed until the partial pressure decreases to 1 mmHg or less, the thermal conductivity decreases as the partial pressure ratio of carbon dioxide to the volatile foaming agent decreases. . Therefore, the effect of reducing the thermal conductivity can be obtained even if the amount of the epoxy compound used is small.
[0020]
Also, the main aim of the present invention is to obtain a good foam by using a foaming agent having poor foamability together with a reactive foaming agent such as water, and to fix carbon dioxide generated from the reactive foaming agent. This is to suppress the increase in thermal conductivity. Therefore, greatly improving the foamability means that carbon dioxide generated in a large amount must be fixed. Thus, there will be an optimal volatile blowing agent boiling point and reactive blowing agent range that satisfies both foamability and carbon dioxide fixation.
Since a volatile foaming agent having a boiling point lower than 40 ° C. can be foamed well without using a reactive foaming agent in combination, the effect of applying the present invention is small. Moreover, since the high boiling point volatile blowing agent has a low vapor pressure, its thermal conductivity is easily affected by the residual carbon dioxide partial pressure. For these reasons, it is preferable to use a volatile blowing agent having a vapor pressure at 25 ° C. of about 50 mmHg or more and a boiling point of 100 ° C. or less. Furthermore, when a volatile foaming agent having a boiling point exceeding 60 ° C. is used as a reactive foaming agent, the amount of water required to improve foaming increases, and at the same time, the amount of epoxy compound required also increases. . Therefore, using a volatile blowing agent having a boiling point of 40-60 ° C. with relatively good foaming properties, reactive foaming of a relatively small amount of water of 0.5 to 1.5 parts by weight with respect to 100 parts by weight of polyol. Use as an agent is most suitable from the viewpoint of cost because the amount of the epoxy compound can be reduced.
[0021]
When the amount of water used as the reactive blowing agent is 1.5 g with respect to 100 g of polyol, the amount of carbon dioxide generated by the reaction of water and polyisocyanate is 1.5 / 18 mol. In addition, if 100 g of polyol and other heat insulating foam materials such as polyisocyanate, volatile foaming agent, epoxy compound, carbon dioxide fixing catalyst are combined, the weight of all materials is usually about 250 to 300 g per 100 g of polyol. Become. Therefore, the amount of carbon dioxide generated by the reaction between the water and the polyisocyanate is (1.5 / 18) / (250/100) = 0.33 mol or less per 100 g of the heat insulating foam. However, since the isocyanates react to generate carbodiimide and the reaction of releasing carbon dioxide also proceeds, the actual amount of generated carbon dioxide is slightly larger than the above value. However, even when there are many, it is about 0.040 mol as a whole. Therefore, even if this is all added to an epoxy group to form a carbonate, only up to 0.040 mol of carbonate per 100 g of the heat insulating foam is formed. The presence of carbonate increases the weight by simply increasing the weight and increasing the weight of the insulating foam if it is not a resin component. Accordingly, it is preferred that the amount of cyclic carbonate be minimized as described above.
[0022]
As for the volatile blowing agent having a boiling point lower than 40 ° C., the role of water as the reactive blowing agent to be added is relatively lowered as described above, and from the viewpoint of production, it is 0 for 100 parts by weight of polyol. A small amount of about 5 parts by weight is sufficient. However, when a compound such as hydrofluorocarbon (HFC) having a fluorine atom that is more expensive than an epoxy compound is used as a volatile foaming agent, addition of water and fixation of generated carbon dioxide are in addition to improving foamability. This is important in terms of reducing costs by reducing volatile blowing agents. Accordingly, even when a volatile blowing agent having a boiling point of 40 ° C. or less is used, if it is expensive, for example, hydrofluorocarbon, especially 1,1,1,3,3-pentafluoropropane advantageous from the viewpoint of thermal conductivity, etc. Is preferably used as a volatile foaming agent, and water as a reactive foaming agent is used in an amount of 0.5 parts by weight or more based on 100 parts by weight of polyol, thereby reducing the amount of the volatile foaming agent used.
[0023]
Moreover, in the manufacturing method of the heat insulation foam of this invention, it has an epoxy group more than 1 molar equivalent with respect to the stoichiometric molar amount of the carbon dioxide generated by reaction with a reactive foaming agent and polyisocyanate. It is preferred to use an amount of epoxy compound. Furthermore, it is particularly preferable that the polyisocyanate has 0.7 to 1.1 molar equivalents of NCO groups with respect to the molar amount of hydroxyl groups in the polyurethane raw material. This is due to the following reason.
During the polyurethane resin formation reaction, the reaction between the epoxy group and the polyisocyanate proceeds, and the epoxy group that should react with carbon dioxide is consumed. Here, as described above, it is effective to increase the amount of the epoxy group and to reduce the polyisocyanate that causes a side reaction with the epoxy group. Under such conditions, the amount of epoxy groups remaining without side reaction is sufficient, and the fixation of carbon dioxide proceeds smoothly.
[0024]
The epoxy compound used here is easy to disperse or dissolve in other materials such as polyol if it is liquid at a temperature of 10 ° C. or higher and 30 ° C. or lower, which is an atmospheric temperature for producing a heat insulating foam. The mixing operation in production proceeds well. As a result, the fixation of carbon dioxide is easy to proceed, which is preferable.
The heat insulating foam of the present invention has the following molar concentrations of the epoxy group of the epoxy compound contained in the polyurethane resin composition after foam molding, the carbon dioxide generated by the reaction of the reactive foaming agent and the isocyanate group of the polyisocyanate: It is preferable that the relationship satisfies the formula (4). If this relationship is satisfied, the reaction to fix the carbon dioxide continues even if the epoxy group reacts with the polyisocyanate and is lost, or even when the isocyanate groups react with each other after foam molding to generate new carbon dioxide. Progresses and carbon dioxide decreases.
Furthermore, when an excess epoxy group exists and the relationship of Formula (5) is satisfied, it is preferable because fixation of carbon dioxide proceeds more efficiently and faster.
[0025]
[Equation 3]

[0026]
However, even if the amount of epoxy groups is large, corresponding to the inequality sign on the left side of equation (5), the fixation rate of carbon dioxide saturates and the ultimate thermal conductivity does not decrease. From the viewpoint of reducing the amount of the epoxy group, an epoxy group amount satisfying the above formula is preferable. In addition, the epoxy group concentration, carbon dioxide concentration, and isocyanate group concentration referred to here are the number of epoxy groups, the number of carbon dioxide molecules in a gaseous state, and the number of isocyanate groups in a certain heat insulating foam. It can be grasped by analysis by a liquid chromatogram of an extract with a solvent from the heat insulating foam, analysis by gas chromatogram of gas in the heat insulating foam, or infrared absorption analysis of the heat insulating foam piece.
[0027]
Such a condition is realized by taking the following preferable manufacturing method of the present invention.
The fixing speed of carbon dioxide at the time of production and thereafter increases as the amount of the carbon dioxide fixing catalyst is increased. However, since many carbon dioxide-immobilized catalysts have activity in the urethane reaction, the control of the urethane reaction becomes difficult if many of them are used. Therefore, it is important to ensure a sufficient and minimum amount of epoxy groups. Then, the required carbon dioxide fixation rate may be realized by adjusting the amount of carbon dioxide fixation catalyst.
[0028]
As the amount of epoxy groups for realizing the required carbon dioxide fixation rate, in the method for producing a heat insulating foam of the present invention, with respect to the molar amount of carbon dioxide stoichiometrically generated from water as the reactive foaming agent. It is preferable to use an epoxy compound in an amount having an epoxy group of 2.5 molar equivalents or more and 4 molar equivalents or less. Most carbon dioxide is fixed by using an epoxy group of 2.5 molar equivalents or more. And if the quantity of an epoxy group is increased, the speed | rate which fixes a carbon dioxide will increase, but even if it uses more than 4 molar equivalent, the thermal conductivity which the foam obtained reaches does not change so much.
By using such an epoxy amount, the above formulas (4) and (5) can be used even in a normal formulation using an amine catalyst as a urethane reaction catalyst and a zinc halide and onium salt as a carbon dioxide fixing catalyst. The left side is filled. Furthermore, if the epoxy compound is used in an amount of 3.5 to 4 molar equivalents relative to the molar amount of carbon dioxide resulting from the reaction of polyisocyanate with the water of the reactive foaming agent, one satisfying the formula (5) can be obtained.
[0029]
As the catalyst for urethane reaction used in the method for producing a heat-insulating foam of the present invention, an organic tin catalyst such as dibutyltin laurate is preferably used because it does not promote the reaction between an epoxy group and an isocyanate. In this case, since the residual amount of the epoxy group is increased as compared with the case of using a normal amine catalyst as the urethane reaction catalyst, the amount of the epoxy compound to be used can be reduced. Moreover, when the same epoxy compound amount is used, the time required for fixing carbon dioxide is shortened.
In addition, a method of adding an amine catalyst that accelerates foaming to a slow-foaming organotin-based catalyst or adding formic acid that foams faster than water as a reactive foaming agent is a preferable urethane reaction. This is the adjustment method.
[0030]
Furthermore, a part of the excess epoxy compound is part of the resin component that constitutes the cell membrane or skeleton by the reaction with polyisocyanate or the epoxy ring-opening reaction subjected to the action of the urethane reaction catalyst in the process of forming the heat insulating foam. Captured as part. In addition, most liquid epoxy compounds are solidified by a reaction for fixing carbon dioxide, so that adverse effects such as shrinkage hardly occur.
In particular, an epoxy compound having 2 to 4 epoxy groups in one molecule is produced by a bubble membrane or an epoxy ring-opening reaction that is affected by a reaction with a polyisocyanate or a urethane reaction catalyst in the process of forming a heat-insulating foam. Since the crosslinked structure is formed as a part of the resin component constituting the skeleton, a hybrid structure of urethane resin and epoxy resin is formed, and the mechanical strength is increased.
In addition, an epoxy compound having 1 to 3 hydroxyl groups in one molecule is crosslinked as a part of the resin component constituting the cell membrane or skeleton by the reaction of the hydroxyl groups and polyisocyanate in the process of forming the heat insulating foam. Since the structure is constituted, a hybrid structure of urethane resin and epoxy resin is constituted, and mechanical strength is increased.
[0031]
As described above, according to the present invention, the reactive foaming agent added to the raw material can generate carbon dioxide by reacting with the polyisocyanate and contribute to the formation of bubbles in the heat insulating foam. Moreover, the carbon dioxide in the bubbles of the heat insulating foam to be formed is fixed by the epoxy compound. This makes it possible to improve the filling property of the polyurethane foam into the heat insulating box, improve the heat insulating performance of the heat insulating foam, and improve the mechanical strength.
Typical examples of the epoxy compound having 2 to 4 epoxy groups in one molecule include trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, and bisphenol A type epoxy resin.
Typical epoxy compounds having 1 to 3 hydroxyl groups in one molecule are glycidol, glycerol polyglycidyl ether, sorbitol polyglycidyl ether, and the like.
[0032]
The volatile compound used as the bubble-filled gas used in the present invention can be used as long as it has a boiling point of 150 ° C. or lower and a molecular weight of 70 or higher, but the following compounds are particularly preferable.
First, a cyclic hydrocarbon is preferable for improving the heat insulating properties. Examples of this are the cyclic hydrocarbons cyclopentane (molecular weight 70.14), cyclohexane (molecular weight 84.16), cyclohexene (molecular weight 82.15), 1,4-cyclohexadiene (molecular weight 80.13), 1,3- Cyclohexadiene (molecular weight 80.13), quadricyclane (molecular weight 92.14) and aromatic compounds benzene (molecular weight 78.11), toluene (molecular weight 92.14), thiophene (molecular weight 84.1), fluorobenzene (Molecular weight 96.1), chlorobenzene (molecular weight 113.56) and the like are preferably used. In order that the thermal conductivity is hardly affected by impurities such as air, those having 5 to 6 carbon atoms with a saturated vapor pressure of about 100 mmHg or more at room temperature are most suitable.
In addition, from the viewpoint of thermal conductivity, pyrimidine (molecular weight 80.09), pyrazine (molecular weight 80.09), pyridine (molecular weight 79.10), tetrahydrofuran (molecular weight 72.11), tetrahydrapyran (molecular weight 86. 13), 1,3-dioxolane (molecular weight 74.1), dioxane (molecular weight 88.1), 1,4-dioxene (molecular weight 86.1), trioxane (molecular weight 90.07), thiazole (molecular weight 85. 12), 2-methoxy-1,3-dioxolane (molecular weight 104.11) and the like.
[0033]
Further, from the viewpoint of reducing the thermal conductivity, the fluoride is a highly fluorinated hydrocarbon having a high molecular weight of 3 to 7 or a fully fluorinated hydrocarbon, a fluorinated ether having 3 to 8 carbon atoms, 3 to 6 carbon atoms. A structure in which the vapor of the fluorinated tertiary amine becomes a filling gas is particularly preferable.
Examples of the highly fluorinated or wholly fluorinated fluorinated hydrocarbons having 3 to 11 carbon atoms include linear, branched, and cyclic hydrocarbons. For example, 1,1,1,4,4,4-hexafluorobutane (molecular weight 166, boiling point 24.6 ° C.), 1,1,1,3,3-pentafluoropropane (molecular weight 134, boiling point 14 ° C.), 1,1,2,2,3-pentafluoropropane (molecular weight 134, boiling point 26 ° C.), perfluorohexane (molecular weight 338, boiling point 60 ° C.), perfluorocyclohexane (molecular weight 300), perfluoroheptane (molecular weight 370, boiling point) 80 ° C), perfluoro (methylcyclohexane) (molecular weight 350, boiling point 76 ° C), perfluoro (methylcyclopentane) (molecular weight 300, boiling point 60 ° C), perfluoropentane (molecular weight 288, boiling point 29.5 ° C), perfluoro Fluorocyclopentane (molecular weight 250), perfluoroisopentane (molecular weight 288), perfluoro-3-methyl Rubutane (molecular weight 288), perfluoro-2,2-dimethylpropane (molecular weight 288), perfluoroisohexane (molecular weight 338), perfluoro-3-methylpentane (molecular weight 338), perfluoro-2,2-dimethylbutane (Molecular weight 338), perfluoro-2,3-dimethylbutane (molecular weight 338), perfluorodimethylcyclobutane (molecular weight 300), and the like can be applied. Further, as a highly fluorinated hydrocarbon which is considered to have a short lifetime in the atmosphere and have little influence on global warming, there is a highly fluorinated alkene, such as perfluoro-2-methyl-2-pentene, perfluoro- 4-methyl-2-pentene, perfluoro-2-pentene, (perfluorobutyl) ethylene, (perfluoroisopropyl) ethylene, hexafluoropropene, hexafluoro-1,3-butadiene, octafluoro-2- Butene, octafluorocyclopentene, 3,3,4,4,4-pentafluorobutene-1, perfluoroheptene-1, perfluorooctene-1, 1H, 1H, 2H-perfluoro-1- Octene, tetrafluoroethylene, etc. can be applied.
[0034]
Further, the highly fluorinated or wholly fluorinated ethers of 3 to 8 carbon atoms include linear, branched, and cyclic ones. For example, 2,2,3,3,3-pentafluoropropyl methyl ether (molecular weight 164, boiling point 46 ° C.), 2,2,3,3,3-pentafluoropropyl-1,1,2,2-tetrafluoro Ethyl ether (molecular weight 250, boiling point 58 ° C.), 1,1,2,2-tetrafluoroethyl methyl ether (molecular weight 132, boiling point 38 ° C.), 1,1,3,3,3-pentafluoro-2-trifluoro Methylpropyl methyl ether (molecular weight 232, boiling point 68-74 ° C.), perfluorodiethyl ether (molecular weight 254), perfluoro-2-butyltetrahydrofuran (molecular weight 416, boiling point 99-107 ° C.), 1,1,2,3 3,3-hexafluoropropyl methyl ether (molecular weight 180.06, boiling point 53 ° C.), 2,2,2-trifluoroethyl difur B methyl ether (molecular weight 150.04, boiling point 29 ° C.) and the like can be applied.
Further, as the highly fluorinated or fully fluorinated tertiary amine having 3 to 6 carbon atoms, any of linear, branched and cyclic structures can be applied. For example, perfluorotriethylamine (molecular weight 371), perfluoropyridine (molecular weight 169, boiling point 89 ° C.) and the like are preferably used.
[0035]
Furthermore, in the manufacturing method demonstrated above, a bubble diameter can also be adjusted by controlling the pressure in the container which performs foam molding using a vacuum pump. In the case of foam molding under normal pressure, the timing of polyurethane formation and foaming is determined by the boiling point of the foaming agent. If the boiling point of the foaming agent is low and the foaming is too early, the resin becomes too soft and the bubbles become large. On the other hand, if the boiling point of the foaming agent is too high, the heat necessary for foaming cannot be obtained depending on the polyurethane formation reaction, or even if it is obtained, the foaming slows down and the resin becomes hard, resulting in a sufficient volume increase. Absent. Therefore, only a blowing agent having a boiling point from about room temperature to about 50 ° C. is used. On the other hand, in the method of the present invention, the foaming time can be adjusted by controlling the degree of decompression in the container for foam molding. For this reason, it becomes possible to determine suitably the polyurethane formation reaction and the timing of foaming, and it is possible to easily produce a foam having a desired cell diameter and excellent heat insulating properties. Further, it becomes possible to use a volatile compound having a high boiling point and a low thermal conductivity, and it becomes easy to produce an excellent heat insulating foam. Suitable timing of foaming is determined experimentally. That is, the bubble diameter of the resulting foaming agent is examined by changing the pressure reduction start time by the vacuum pump and the pressure reduction speed. When the bubble diameter is small, the decompression time is advanced to increase the decompression speed, and when the bubble diameter is large, the decompression period is delayed to slow down the decompression speed.
[0036]
Further, when the pressure in the container for foam molding is reduced and foamed, the amount of the reactive foaming agent required is small, so that the time required for fixing the reactive foaming agent is short. . Therefore, even if the reactive foaming agent is flammable, since the amount used is small, the safety in the manufacturing process is high.
Moreover, it is desirable to remove impurities such as air from the viewpoint of obtaining a highly heat-insulating foam. In particular, when the vapor pressure of the volatile compound in the closed cell is lowered, the influence of impurities becomes large, and therefore the operation for removing this becomes important. It is also possible to remove impurities such as air by reducing the pressure with a vacuum pump or the like. However, in order to remove completely, the inside of the container to be foamed is replaced with a specific gas, and the polyurethane raw material is bubbled with a specific gas, or the bubbling and vacuum removal by a vacuum pump are repeated. The specific gas used is flame retardant from the viewpoint of safety, and preferably has a low thermal conductivity so as not to increase the thermal conductivity when a trace amount remains. As such a gas, krypton, xenon, or the like is suitable. Highly fluorinated hydrocarbons having a boiling point of -30 to 20 ° C can also be used. A highly fluorinated hydrocarbon is a hydrocarbon in which most of the hydrogen has been replaced with fluorine. Since these compounds have a low boiling point, they can be easily recovered by cooling or compression.
[0037]
Also, in order to inject the urethane raw material into the container, it may be injected under pressure with the gas, particularly krypton, xenon, or carbon dioxide.
The carbon dioxide that has acted as a blowing agent reacts with the epoxy compound by the action of the carbon dioxide fixing catalyst, and is fixed as a cyclic carbonate. Examples of the epoxy compound include various glycidyl ethers and triethylene oxide. In particular, glycidyl ether includes glycidyl ether, phenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, 2-methyloctyl glycidyl ether, glycerol diglycidyl ether, glycero- Lutriglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether and the like are used. Examples of carbon dioxide fixing catalysts include metal halides such as zinc chloride, zinc bromide and zinc iodide, ammonium salts, phosphonium salts, sulfonium salts, oxonium salts, arsonium salts, stibonium salts, selenonium salts, iodonium salts, stannonium salts. A combination with an onium salt such as a salt is used. Of the onium salts, onium halides are preferably used, and among them, ammonium halides such as tetrabutylammonium bromide and tetrabutylammonium iodide and sulfonium halides are preferable. In addition, for the production of the cyclic carbonate, an alkali metal halide such as lithium chloride, lithium bromide, sodium iodide, lithium iodide and the onium salt may be used alone or in combination. be able to. Further, the addition reaction catalyst may be contained in either the polyol composition or the isocyanate.
[0038]
【Example】
Examples of the present invention will be described below.
FIG. 1 shows a heat insulating box obtained by the following example. The heat insulation box 1 is composed of an ABS resin inner box 2 and an iron outer box 3, and a heat insulation foam 4 made of polyurethane foam filled in a space formed by the inner box 2 and the outer box 3. Has been.
[0039]
Example 1
The polyol component was composed of 100 parts by weight (hereinafter simply referred to as “parts”) of an aromatic amine-based polyether polyol having a hydroxyl value of 460 (mgKOH / g) and a catalyst for urethane reaction (Kaolyzer No. 1 manufactured by Kao Corporation) 2.0. Part, 1.5 parts of foam stabilizer (silicone surfactant F-335 manufactured by Shin-Etsu Chemical Co., Ltd.), 1.0 part of water as a reactive foaming agent, and the free blow density of the heat insulating foam is 25 ~ 27 (kg / m ^Three In the mixed solution prepared by mixing the number of parts of the volatile blowing agent cyclopentane so as to be 15), 15 parts of an epoxy compound phenylglycidyl ether and carbon dioxide fixing catalyst tetrabutylammonium bromide / zinc chloride (1/1) 1 The liquid mixture with the part is mixed. The isocyanate component is a polyisocyanate composed of diphenylmethane diisocyanate having an amine equivalent of 135 (hereinafter referred to as crude MDI).
In addition, 15 parts of phenyl glycidyl ether is added in an amount of 1.8 mole equivalent of an epoxy group with respect to a mole amount of carbon dioxide generated by reaction of 1.0 part of water as a reactive foaming agent and polyisocyanate. Equivalent to.
The polyol component and the isocyanate component thus prepared are mixed using a high-pressure foaming machine at a mixing ratio in which 0.9 molar equivalent of NCO group is blended with respect to the hydroxyl group of the polyol component. Injected into a box body consisting of an inner box and an outer box and allowed to foam. Thus, a heat insulating box filled with a heat insulating foam was obtained.
[0040]
<< Comparative Example A >>
The formulation was the same as in Example 1 except that the blending ratio of the polyol component and the isocyanate component was changed to a ratio in which 0.65 molar equivalent of NCO group was blended with respect to the hydroxyl group of the polyol component.
[0041]
<< Comparative Example B >>
The formulation was the same as in Example 1 except that the blending ratio of the polyol component and the isocyanate component was changed to a ratio in which 1.2 molar equivalents of NCO groups were blended with respect to the hydroxyl group of the polyol component.
[0042]
<< Comparative Example C >>
Except for removing 15 parts of the epoxy compound and 1 part of the carbon dioxide-immobilized catalyst from the polyol component of Example 1 and mixing 25 parts of carbon dioxide adsorbent zeolite (Zeolite 5A manufactured by Tosoh Corporation) with the polyisocyanate component. The same formulation as Example 1 was used.
[0043]
The heat insulating box thus obtained was allowed to stand at room temperature for 4 weeks, and then the heat insulating foam was collected, and the thermal conductivity, core density, and compressive strength of the heat insulating foam were measured. The core density is for evaluating the filling property of the heat insulating foam. Further, in order to confirm the degree of carbon dioxide fixation, the composition of the gas contained in the heat insulating foam was determined. These results are shown in Table 1.
[0044]
[Table 1]

[0045]
In the table, CP represents cyclopentane (the same applies to the following tables).
As is clear from Table 1, the heat insulating foam according to the present example has a very low ratio of carbon dioxide remaining in the closed cells, and has excellent heat insulating performance.
This is thought to be due to the following reason.
That is, polyisocyanate has reaction activity with respect to the hydroxyl group and epoxy compound in the raw material, but the reaction of polyisocyanate and epoxy compound phenylglycidyl ether proceeds more slowly than the reaction of polyisocyanate and hydroxyl group. More importantly, since there are few polyisocyanates with an index as low as 0.9, most of the NCO groups in the polyisocyanate react with hydroxyl groups and the amount of epoxy groups consumed is reduced. For this reason, it becomes possible to leave an epoxy group necessary and sufficient for reaction-immobilizing carbon dioxide remaining inside the bubbles after the heat insulating foam is formed.
[0046]
In addition, phenylglycidyl ether does not inhibit the generation of carbon dioxide due to the reaction between water and polyisocyanate, which is a reactive foaming agent, in the foaming process of the heat insulating foam, and allows the generated carbon dioxide to function as a foaming agent. In addition, carbon dioxide remaining inside the bubbles of the heat insulating foam can be effectively fixed.
In addition, by using phenylglycidyl ether containing 1.8 mol equivalent of excess epoxy group with respect to the molar amount of carbon dioxide generated by the reaction of water and polyisocyanate of the reactive blowing agent, Even if an epoxy ring-opening reaction caused by the action of a urethane reaction catalyst occurs in the production process, an epoxy group necessary for reaction-immobilizing carbon dioxide remaining in the bubbles can remain. Furthermore, a part of phenyl glycidyl ether forms a cross-linked structure as a part of the resin component constituting the cell membrane or skeleton by reaction with polyisocyanate in the process of forming the heat insulating foam, thereby improving the mechanical strength of the heat insulating foam. Will be improved.
[0047]
On the other hand, in Comparative Example A, carbon dioxide generated in the foaming process could be almost completely fixed, and the thermal conductivity of the heat insulating foam could be reduced. However, the mechanical strength of the heat insulating foam deteriorated, and the appearance quality of the heat insulating box was remarkably deteriorated. This is presumably because the compound ratio of NCO groups in the polyisocyanate was too small relative to the hydroxyl groups, so that the unreacted hydroxyl groups did not cause resin cross-linking and lowered the mechanical strength.
Moreover, in the comparative example B, the carbon dioxide generated in the foaming process could not be sufficiently fixed and remained inside the bubbles as it was, and the thermal conductivity of the heat insulating foam could not be reduced. This is presumably because sufficient epoxy groups did not remain to immobilize carbon dioxide due to the reaction between the epoxy compound and the polyisocyanate in the process of forming the heat insulating foam.
In Comparative Example C, the amount of carbon dioxide remaining inside the bubbles could be reduced, but the foaming efficiency was extremely poor. Therefore, the heat insulating foam has a high density and a large variation, and the filling property to the box is extremely poor. Moreover, the compressive strength of the obtained heat insulation foam was also remarkably bad.
[0048]
Example 2
7 parts of tetrabutylammonium bromide / zinc bromide (4/1) and 1.0 molar equivalent of NCO group with respect to the hydroxyl group of the polyol component are incorporated into the carbon dioxide fixing catalyst. The same formulation as in Example 1 was used except that the mixing ratio was changed.
Five hours after foam molding, the gas in the heat insulating foam obtained was analyzed. As a result, the partial pressure of carbon dioxide was lower than the partial pressure of cyclopentane, and the production was completed. The heat conductivity of the obtained heat insulation box after 1 day was 0.0185 W / mk, and the heat conductivity after 7 days was reduced to 0.0180 W / mk. Correspondingly, the partial pressure of carbon dioxide decreases from 110 mmHg to 75 HgmmHg, and the amount of epoxy groups detected by analyzing the methanol extract with a liquid chromatogram decreases by about 20%. An increase was observed.
[0049]
Further, in the above manufacturing process, the inside of the box is replaced with carbon dioxide, and the raw material is injected into the box by the pressure of carbon dioxide in a carbon dioxide atmosphere and foamed. It decreased to 0178 W / mk.
As described above, the decrease in thermal conductivity with time, the decrease in carbon dioxide and epoxy groups, and the increase in carbonate were observed because the reaction between epoxy groups and carbon dioxide continued in the adiabatic foam. it is conceivable that.
In addition, the thermal conductivity was improved by foaming in a carbon dioxide atmosphere. When the raw material was injected at a pressure of air or nitrogen according to a conventional method and foamed in an air or nitrogen atmosphere, the oxygen or nitrogen slightly increased. This is thought to be due to contamination in the heat insulating foam.
[0050]
Example 3
In the raw material composition of Example 2, the amount of epoxy groups was 2.6 molar equivalents relative to the molar amount of carbon dioxide generated by the reaction of water as a reactive blowing agent and polyisocyanate, and other conditions were the same. Thus, a heat insulating box filled with a heat insulating foam was manufactured.
Gas analysis was conducted 12 hours after foam molding, and the partial pressure of cyclopentane was more than three times that of carbon dioxide, and the production was complete.
The heat insulating foam obtained had a thermal conductivity of 0.0175 W / mk after 8 days. Further, the decrease in thermal conductivity almost stopped after 2 weeks, and became 0.0173 W / mk.
Moreover, the epoxy compound was extracted with methanol from the sample piece of the heat insulating foam immediately after foam molding, and the concentration of the epoxy group was measured by liquid chromatography. Similarly, the carbon dioxide concentration contained in the sample piece of the heat insulating foam was measured. Further, the concentration of NCO group was determined by IR measurement. As a result, the concentrations of the epoxy group, carbon dioxide and NCO group were in the relationship of formula (6) in terms of molar concentration. For comparison, the same measurement was performed on Example 1, and the result was Equation (7).
[0051]
[Expression 4]

[0052]
Thus, it is thought that the reason why the thermal conductivity decreased early after the formation of the heat-insulating foam was that more excess epoxy groups remained as described above.
Furthermore, the amount of epoxy groups was increased to 3.5 molar equivalents and 5 molar equivalents with respect to the amount of carbon dioxide generated from the reaction of polyisocyanate and water, and other conditions were the same to produce a heat insulating foam.
When the amount of the epoxy group was 3.5 molar equivalents and 5 molar equivalents, a substantially constant thermal conductivity was reached 3 to 5 days after the production, but both values were 0.0173 W / mk. And even if the amount was increased to 5 molar equivalents, a significant improvement in thermal conductivity could not be achieved as compared to 3.5 molar equivalents.
In each case of 3.5 molar equivalents and 5 molar equivalents, the relationship between the concentration of epoxy groups, carbon dioxide and isocyanate groups in the foam immediately after foam molding is expressed by the formula (5) when the amount of epoxy groups is 5 molar equivalents. 8) When the amount of the epoxy group was 3.5 molar equivalent, the formula (9) was obtained. In the case of 5 molar equivalents, since the epoxy group remains in a large excess, the effect of the epoxy group is saturated, and it is considered that substantially no significant improvement in thermal conductivity was observed.
[0053]
[Equation 5]

[0054]
Example 4
Example 1, except that 1,1,1,3,3-pentafluoropropane was used instead of cyclopentane as the volatile blowing agent, and the amount of water as the reactive blowing agent was 1.2 parts. Thus, a heat insulating foam was produced. This heat insulating foam had a heat conductivity of 0.0171 W / mk after 6 days of foam molding, and had good heat insulating properties. Moreover, since water was used as the reactive foaming agent, the amount of volatile foaming agent used could be reduced.
[0055]
Example 5
In the raw material composition when the epoxy group amount of Example 3 was used at 2.6 molar equivalents with respect to carbon dioxide generated from the reaction of polyisocyanate and water, 0.9 part of dibutyltin laurate as a catalyst for urethane reaction, 9 parts of tetrabutylammonium bromide was used as a carbon dioxide fixing catalyst, and other conditions were the same, and a heat insulating box filled with a heat insulating foam was manufactured.
The heat conductivity of the heat insulating foam obtained reached 0.0175 W / mk after 6 days. Moreover, it was Formula (10) as a result of measuring the molar concentration of the epoxy group in a heat insulation foam, a carbon dioxide, and a NCO group.
[0056]
[Formula 6]

[0057]
In this way, the thermal conductivity decreased earlier because of the action of urethane reaction catalyst and carbon dioxide fixing catalyst, organotin catalyst dibutyltin laurate and onium salt tetrabutylammonium bromide. This combination is thought to be due to the loss of epoxy groups due to side reactions of the epoxy compound, and the excess of epoxy groups remaining as described above.
[0058]
Example 6
The same formulation as in Example 1 was used except that 30 parts of diepoxide obtained by reacting bisphenol A with epichlorohydrin was used as the epoxy compound.
In addition, 30 parts of diepoxide corresponds to an addition amount of 1.6 mole equivalent of an epoxy group with respect to a mole amount of carbon dioxide generated by a reaction between 1.0 part of water and polyisocyanate.
[0059]
<< Comparative Example D >>
The formulation was the same as in Example 6 except that the blending ratio of the polyol component and the isocyanate component was changed to a ratio in which 0.65 molar equivalent of NCO group was blended with respect to the hydroxyl group of the polyol component.
[0060]
<< Comparative Example E >>
The blending ratio of the polyol component and the isocyanate component was the same as that of Example 6, except that 1.2 mole equivalent of NCO group was blended with respect to the hydroxyl group of the polyol component.
[0061]
<< Comparative Example F >>
Example 6 except that 30 parts of diepoxide and 1 part of carbon dioxide-immobilized catalyst were removed from the polyol component of Example 6 and 25 parts of carbon dioxide adsorbent zeolite (Zeolite 5A manufactured by Tosoh Corp.) was mixed with the polyisocyanate component. And the same prescription. Table 2 shows the measured properties of the heat insulating foams collected from the heat insulating boxes obtained in Example 6 and Comparative Examples D, E, and F four weeks after the foam molding.
[0062]
[Table 2]

[0063]
As described above, the heat insulating foam according to this example has a low carbon dioxide ratio in the gas component remaining inside the bubbles and has excellent heat insulating performance.
This is because the epoxy compound diepoxide effectively works to immobilize carbon dioxide, and forms a crosslinked structure as a part of the resin component constituting the cell membrane and skeleton by reaction with polyisocyanate and epoxy ring-opening reaction. This is because the resin was also made into a resin by an immobilization reaction with carbon dioxide.
[0064]
On the other hand, in Comparative Example D, carbon dioxide generated in the foaming process could be almost completely fixed, and the thermal conductivity of the heat insulating foam could be reduced. However, the mechanical strength of the heat insulating foam decreased, resulting in a marked deterioration in the appearance quality of the heat insulating box. This is considered to be due to the same reason as in Comparative Example A.
Further, in Comparative Example E, carbon dioxide generated in the foaming process could not be sufficiently fixed and remained inside the bubbles as it was, and the thermal conductivity of the heat insulating foam could not be reduced. This is considered to be due to the same reason as in Comparative Example B.
Further, in Comparative Example F, the foaming efficiency was extremely poor as in Comparative Example C, and the compression strength of the obtained heat insulating foam was extremely low.
[0065]
Example 7
The same formulation as in Example 1 was used except that 20 parts of glycerol diglycidyl ether was used as the epoxy compound.
Note that 20 parts of glycerol diglycidyl ether corresponds to an addition amount of 1.8 mole equivalents of epoxy groups per mole of carbon dioxide generated by the reaction of 1.0 part of water and polyisocyanate.
[0066]
<< Comparative Example G >>
The blending ratio of the polyol component and the isocyanate component was the same as that of Example 7, except that the ratio of 0.65 molar equivalent of NCO group to the hydroxyl group of the polyol component was blended.
[0067]
<< Comparative Example H >>
The blending ratio of the polyol component and the isocyanate component was the same as that of Example 7, except that the ratio of 1.2 molar equivalent of NCO group to the hydroxyl group of the polyol component was blended.
[0068]
<< Comparative Example I >>
Except that 20 parts of glycerol diglycidyl ether and 1 part of carbon dioxide fixing catalyst were removed from the polyol component of Example 7, and 25 parts of carbon dioxide adsorbent zeolite (Zeolite 5A manufactured by Tosoh Corporation) was mixed with the polyisocyanate component. The formulation was the same as in Example 7.
Table 3 shows the measured properties of the heat insulating foams collected from the heat insulating boxes obtained in Example 7 and Comparative Examples G, H, and I four weeks after foam molding.
[0069]
[Table 3]

[0070]
Thus, the heat insulation foam by a present Example reduces the carbon dioxide ratio in the gas component which remains inside a bubble, and has the outstanding heat insulation performance.
This is because the epoxy compound glycerol diglycidyl ether effectively works to immobilize carbon dioxide and becomes a part of the resin component.
In Comparative Example G, carbon dioxide generated in the foaming process could be almost completely fixed, and the thermal conductivity of the heat insulating foam could be reduced. However, the mechanical strength of the heat insulating foam decreased, resulting in a marked deterioration in the appearance quality of the heat insulating box. This is considered to be due to the same reason as in Comparative Example A.
Further, in Comparative Example H, carbon dioxide generated in the foaming process could not be sufficiently fixed and remained inside the bubbles as it was, and the thermal conductivity of the heat insulating foam could not be reduced. This is considered to be due to the same reason as in Comparative Example B.
In Comparative Example I, the foaming efficiency was very poor as in Comparative Example C, and the compression strength of the heat insulating foam obtained was extremely low.
[0071]
Example 8
The polyol component was composed of 100 parts by weight of an aromatic amine-based polyether polyol having a hydroxyl value of 460 mgKOH / g, 2.0 parts of a urethane reaction catalyst (Kaolyzer No. 1 manufactured by Kao Corporation), and a foam stabilizer (Shin-Etsu Chemical Co., Ltd.). ) Silicone-based surfactant F-335) 1.5 parts, 1.0 part water of reactive foaming agent, and free blow density of heat insulation foam is 25 to 27 (kg / m) ^Three ) To a mixed solution prepared by mixing the number of parts of the volatile blowing agent cyclopentane so as to be 25), 25 parts of an epoxy compound phenylglycidyl ether, and tetrabutylammonium bromide / zinc chloride (1/1) 2 as a carbon dioxide fixing catalyst. The liquid mixture with the part is mixed. The isocyanate component is a polyisocyanate composed of crude MDI having an amine equivalent of 135.
In addition, 25 parts of phenyl glycidyl ether is equivalent to the addition amount which an epoxy group contains 4.0 molar equivalent with respect to the molar amount of the carbon dioxide generated by reaction of 1.0 part of water of a reactive foaming agent, and polyisocyanate. To do.
The polyol component and the isocyanate component thus prepared are mixed using a high-pressure foaming machine at a mixing ratio in which 1.15 molar equivalents of NCO groups are blended with respect to the hydroxyl group of the polyol component. Injected into a box body consisting of an inner box and an outer box and allowed to foam. Thus, a heat insulating box filled with a heat insulating foam was obtained.
[0072]
<< Comparative Example J >>
The amount of phenylglycidyl ether blended is 7.5 parts, that is, 0.9 mole equivalent of epoxy groups with respect to the molar amount of carbon dioxide generated by the reaction of 1.0 part of water of the reactive blowing agent and polyisocyanate. The formulation was the same as in Example 8 except that the content of
[0073]
<< Comparative Example K >>
Except that 25 parts of phenylglycidyl ether and 2 parts of carbon dioxide-immobilized catalyst were removed from the polyol component of Example 7, and 25 parts of carbon dioxide adsorbent zeolite (Zeolite 5A manufactured by Tosoh Corporation) was mixed with the polyisocyanate component. The formulation was the same as in Example 8.
Table 4 shows the measured properties of the heat insulating foams collected from the heat insulating boxes obtained in Example 8 and Comparative Examples J and K three weeks after foam molding.
[0074]
[Table 4]

[0075]
Thus, the heat insulation foam by a present Example reduces the ratio of the carbon dioxide which remains in the inside of the bubble, and has the outstanding heat insulation performance.
This is because phenyl glycidyl ether contains 4.0 molar equivalents of excess epoxy groups relative to the molar amount of carbon dioxide generated by the reaction of water and polyisocyanate, so that carbon dioxide remaining inside the bubbles can be reduced. This is probably because the reaction could be immobilized effectively.
Moreover, when this heat insulating foam was analyzed according to the method of Example 3 immediately after foaming, it was confirmed that the formula (6) was satisfied and a sufficient amount of epoxy groups remained. At this time, the carbon dioxide partial pressure was already lower than the cyclopentane partial pressure, and the production was completed. Further, the same analysis was conducted one month after foam molding, but the remaining epoxy group was confirmed, and the formula (4) was satisfied.
At this time, when the gas in the heat insulating foam was analyzed, the partial pressure of cyclopentane was 360 mmHg. And The partial pressure of cyclopentane is better From the partial pressure of carbon dioxide High and production was complete.
Further, phenyl glycidyl ether is considered to be part of the resin component as in Example 1 and to contribute to strength improvement.
[0076]
In Comparative Example J, carbon dioxide generated in the foaming process could not be sufficiently fixed and remained inside the bubbles as it was, and the thermal conductivity of the heat insulating foam could not be reduced. This is probably because the amount of the epoxy compound was insufficient.
In Comparative Example K, the amount of carbon dioxide remaining inside the bubbles could be reduced to some extent, but the foaming efficiency was extremely poor. For this reason, the heat insulating foam has a high density, a large variation, and the filling property into the box was extremely poor. Moreover, the compressive strength of the obtained heat insulation foam was also remarkably low.
[0077]
Moreover, the extract extracted with the methanol from the heat insulating foam piece of the said Example was quantified with the liquid chromatogram. As a result, 0.025 mol of 4- (phenoxymethyl) -1,3-dioxolan-2-one, a product cyclic carbonate obtained by addition reaction of carbon dioxide with phenylglycidyl ether, was detected per 100 g of the heat insulating foam. Since the amount of water used for the reactive foaming agent was as small as 1 g with respect to 100 g of polyol, the amount of carbon dioxide generated from the reaction of water and polyisocyanate was also small, and the amount of carbonate produced was suppressed to a small amount.
[0078]
Example 9
The same formulation as in Example 8 was used except that 50 parts of diepoxide obtained by reacting bisphenol A with epichlorohydrin was used as the epoxy compound.
Note that 50 parts of diepoxide corresponds to an addition amount of 2.6 mole equivalent of an epoxy group with respect to a mole amount of carbon dioxide generated by a reaction between 1.0 part of water and polyisocyanate.
[0079]
<< Comparative Example L >>
The number of blended parts of diepoxide is 17 parts, that is, the ratio of epoxy group containing 0.9 molar equivalent to the molar amount of carbon dioxide generated by the reaction of 1.0 part of water and polyisocyanate. The formulation was the same as in Example 9.
[0080]
<< Comparative Example M >>
The same formulation as in Example 9 except that 50 parts of diepoxide and 2 parts of carbon dioxide fixing catalyst were removed from the polyol component, and 25 parts of carbon dioxide adsorbent zeolite (Zeolite 5A manufactured by Tosoh Corporation) was mixed with the polyisocyanate component. It was.
Table 5 shows the measured properties of the heat insulating foams collected from the heat insulating boxes obtained in Example 9 and Comparative Examples L and M after 3 weeks of foam molding.
[0081]
[Table 5]

[0082]
The heat insulating foam according to this example has a very low ratio of carbon dioxide remaining inside the bubbles, and has excellent heat insulating performance. Moreover, it has sufficient compressive strength.
In Comparative Example L, carbon dioxide generated in the foaming process could not be sufficiently fixed and remained inside the bubbles as it was, and the thermal conductivity of the heat insulating foam could not be reduced. This is considered to be due to the same reason as in Comparative Example J.
Further, in Comparative Example M, the foaming efficiency was extremely poor as in Comparative Example K, and the compressive strength of the obtained heat insulating foam was extremely low.
[0083]
Example 10
The same formulation as in Example 8 was used except that 30 parts of glycerol diglycidyl ether was used as the epoxy compound.
Note that 30 parts of glycerol diglycidyl ether corresponds to an addition amount of 2.6 molar equivalents of epoxy groups with respect to the molar amount of carbon dioxide generated by the reaction of 1.0 part of water and polyisocyanate.
[0084]
<< Comparative Example N >>
The number of blended parts of glycerol diglycidyl ether was 10 parts, that is, the ratio of the epoxy group containing 0.9 molar equivalent to the molar amount of carbon dioxide generated by the reaction of 1.0 part of water and polyisocyanate. The other formulation was the same as in Example 10.
[0085]
<< Comparative Example O >>
Example 10 except that 30 parts of glycerol diglycidyl ether and 2 parts of carbon dioxide fixing catalyst were removed from the polyol component, and 25 parts of carbon dioxide adsorbent zeolite (Zeolite 5A manufactured by Tosoh Corporation) were mixed with the polyisocyanate component. The same prescription was used.
[0086]
Table 6 shows the measured properties of the heat insulating foam obtained after 3 weeks of foam molding from the heat insulating box obtained in Example 10 and Comparative Examples L and M.
The heat insulating foam according to this example has excellent heat insulating performance and sufficient compressive strength as in Example 8.
In Comparative Example N, carbon dioxide generated in the foaming process could not be sufficiently fixed and remained inside the bubbles as it was, and the thermal conductivity of the heat insulating foam could not be reduced. This is considered to be due to the same reason as in Comparative Example L.
Further, in Comparative Example O, the foaming efficiency was extremely poor as in Comparative Example K, and the compressive strength of the obtained heat insulating foam was extremely low.
[0087]
[Table 6]

[0088]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain a heat insulating foam excellent in heat insulation using a foaming agent having a small load on global environmental problems such as ozone layer destruction and global warming. Moreover, according to this invention, such an excellent heat insulation foam can be produced with a simple manufacturing process.
[Brief description of the drawings]
FIG. 1 is a perspective view in which a part of a heat insulation box is cut out according to an embodiment of the present invention.
[Explanation of symbols]
1 Insulation box
2 Inner box
3 Outer box
4 Thermal insulation foam

Claims (15)

It is composed of a foamed polyurethane resin composition having closed cells, and the closed cells contain vapor of a volatile compound having a boiling point of 150 ° C. or less and a molecular weight of 70 or more at 25 ° C. and a partial pressure of 5 mmHg or more, and carbon dioxide. It is contained at a partial pressure lower than the partial pressure of the volatile compound, and the wall surface of at least closed cells of the resin composition is an addition reaction product of carbon dioxide to an epoxy group in the presence of a carbon dioxide fixing catalyst. A heat-insulating foam comprising a solid or liquid cyclic carbonate compound. 2. The heat insulating foam according to claim 1, wherein the volatile compound has a boiling point of 40 ° C. or more and 100 ° C. or less, and a partial pressure in the closed cells is 50 mmHg or more and 450 mmHg or less. The heat insulation foam of Claim 2 whose partial pressure in the said closed cell of the said volatile compound is 10 times or more of the partial pressure of a carbon dioxide. The heat insulating foam according to claim 1 or 2, wherein the volatile compound is cyclopentane or 1,1,1,3,3-pentafluoropropane. The heat insulating foam according to claim 1 or 2, wherein an amount of the cyclic carbonate is less than 0.040 mol with respect to 100 g of the heat insulating foam. The polyurethane resin composition contains an epoxy compound that is liquid at 10 ° C. or higher and 30 ° C. or lower, and carbon dioxide in the closed cells reacts with the epoxy group of the epoxy compound over time in the presence of the carbon dioxide fixing catalyst. The heat insulating foam according to claim 1 or 2, wherein a solid or liquid cyclic carbonate compound is formed, and the epoxy group decreases and the cyclic carbonate compound increases. The heat insulating foam according to claim 6, wherein the molar concentration of the epoxy group of the epoxy compound, carbon dioxide and the isocyanate group of the polyisocyanate contained in the polyurethane resin composition immediately after the foam molding satisfies the following formula.

Mixing and foaming raw materials containing polyisocyanate, polyol, foam stabilizer, urethane reaction catalyst, reactive foaming agent, volatile foaming agent with a boiling point of 150 ° C or less and a molecular weight of 70 or more, an epoxy compound, and a carbon dioxide fixing catalyst A mixing / foaming step of forming a foamed polyurethane resin composition having closed cells containing carbon dioxide generated by the reaction of the reactive foaming agent and the polyisocyanate and the volatile foaming agent; An addition reaction with an epoxy group of the epoxy compound in the presence of a carbon dioxide fixing catalyst forms a solid or liquid cyclic carbonate compound, whereby the inside of the bubbles substantially contains the volatile foaming agent. A step of obtaining a foam having a partial pressure of the steam of 5 mmHg or more at 25 ° C. The method of production. The method for producing a heat insulating foam according to claim 8, wherein the epoxy compound is liquid at a temperature of 10 ° C. or higher and 30 ° C. or lower. The polyisocyanate has 0.7 to 1.1 molar equivalents of NCO groups with respect to the molar amount of hydroxyl groups in the raw material, and the epoxy compound reacts with the reactive blowing agent and the polyisocyanate. The manufacturing method of the heat insulation foam of Claim 8 or 9 which has 1 mol equivalent or more of epoxy groups with respect to the molar amount of the carbon dioxide generate | occur | produced by. The method for producing a heat insulating foam according to claim 8 or 9, wherein the reactive foaming agent is water, and the amount thereof is 0.5 part by weight or more and less than 1.5 parts by weight with respect to 100 parts by weight of the polyol. The heat insulation foam of Claim 11 in which the said epoxy compound has an epoxy group of 2.5-4 molar equivalent with respect to the molar amount of the carbon dioxide generated by reaction with the said reactive foaming agent and the said polyisocyanate. Manufacturing method. The adiabatic foam according to claim 8 or 9, wherein the epoxy compound is selected from the group consisting of a compound having 2 to 4 epoxy groups in one molecule and a compound having 1 to 3 hydroxyl groups in one molecule. Body manufacturing method. The method for producing a heat-insulating foam according to claim 8 or 9, wherein a combination of an organic tin compound and an onium salt acts as the urethane reaction catalyst and the carbon dioxide fixing catalyst. The mixing / foaming step is performed in a container substituted with at least one gas selected from the group consisting of xenon, krypton, and carbon dioxide, and injection of the polyurethane raw material into the container is performed by adding the gas. The manufacturing method of the heat insulation foam of Claim 8 or 9 performed by pressure.

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