JP4822381B2 - Radiation heat insulation board and heat insulation method using the same - Google Patents

Description

ただし、α₁は高温帯域の流体の熱伝達率、Ｔｒは高温帯域の流体の温度、Ｔ₁は断熱板の高温帯域側の表面温度、λは断熱板の熱伝導率、Ｌは断熱板の厚さ、Ｔ₂は断熱板の低温帯域側の表面温度、α₂は低温帯域の流体の熱伝達率、Ｔ₀は低温帯域の流体の温度である。
【００１４】
また、断熱板を介しての放射による熱Ｑ₂の伝達は、高温帯域の物体及び流体から放射及び伝導により高温帯域側の壁表面へ伝達され、次いで壁面を熱伝導で伝達されたのち、低温帯域側の壁表面から低温帯域の物体及び流体に放射で伝達される。これを式で表わすと次のようになる。
【００１５】
Ｑ₂＝σ×ｆ（ε₁）×［（１００／Ｔｒ）⁴−（１００／Ｔ₁）⁴］
＝λ／Ｌ（Ｔ₁−Ｔ₂）
＝σ×ｆ（ε₂）×［（１００／Ｔ₂）⁴−（１００／Ｔ₀）⁴］
ただし、σはステファン・ボルツマン定数、ｆ（ε₁）は高温帯域の物体間の放射伝熱の放射係数、Ｔｒは高温帯域の物体又は流体の温度、Ｔ₁は断熱板の高温帯域側の表面温度、λは断熱板の熱伝導率、Ｌは断熱板の厚さ、Ｔ₂は断熱板の低温帯域側の表面温度、ｆ（ε₂）は低温帯域の物体間の放射伝熱の放射係数、Ｔ₀は低温帯域の物体又は流体の温度である。
この場合、放射熱伝達と対流熱伝達とを別個に取り扱っているが、実際には放射と対流による熱伝達は同時に行われる。
【００１６】
キルヒ・ホッフの法則によると、吸収率と放射率とは等しくなるため、壁体表面の放射熱吸収率が大きいと高温帯域及び低温帯域の放射伝熱の放射係数が大きくなり、放射熱伝達量が増加する。また、高温帯域の物体及び流体と壁面となる物体間の放射係数が小さく、低温帯域の物体及び流体と壁面となる物体間の放射伝熱の放射係数が大きい場合、壁面となる物体の温度は低下する。
【００１７】
したがって、透明層の熱容量が基体の熱容量の１０％以下で、透明層の放射熱吸収が基体の放射熱吸収の６０％以下の断熱板は、上記の条件になると、熱伝導性基体の温度が低下し、熱伝導性透明層と熱伝導性基体との間で温度傾斜を形成することが困難となる。
【００１８】
ところで、上記の熱伝導性基体の温度低下を阻止するには、第１層すなわち熱伝導性透明層と第２層すなわち熱伝導性基体層とを透過した放射熱を反射させ、第２層における放射熱の吸収を増大させて、熱伝導性透明層と熱伝導性基体層との間の温度傾斜を常時形成させればよい。
【００１９】
なお、ここでいう熱容量とは、これをｑで表わしたとき、次の式で定義されるパラメーターである。
ｑ＝Ｖ・ｄ・ｃ
＝Ｗ・ｃ
ただし、ｃは比熱（ｃａｌ／ｇ・Ｋ）、ｄは密度（ｇ／ｃｍ³）、Ｖは全体積（ｃｍ³）、Ｗは全質量（ｇ）である。
したがって、熱容量ｑは、比熱ｃ、密度ｄ及び全質量Ｗに比例するパラメーターであることが分る。
【００２０】
この比熱ｃは、物体を構成する各材料に固有のもので、その数値は温度により変化するが、通常は、慣用の比熱測定装置を用い、室温で測定して得た値が用いられる。なお、この熱容量は、比熱や密度が同一の材料を用いても、例えば単位面積当りの厚さを増減して全体積を変えることによって任意に調節することができる。
なお、ここでいう放射熱吸収率及び放射熱反射率としては、赤外分光光度計（ＦＴＩＲ）により測定した数値を用いることができる。
【００２１】
他方、熱源となる物体から放射される放射線例えば光は温度が高くなればなるほど加速度的に多くのエネルギーを放出し、所定温度Ｔ（Ｋ）において放出される放射線の最大強度の中心波長（λ）は、ウィーンの変位則により、次式によって求められる。
λ＝２８９８／Ｔ
【００２２】
他方、物体に入射する放射線は、その物体が完全黒体の場合は全部吸収されるし、完全白体の場合は全部反射される。そして、物体が完全透明体の場合は全部透過されるが、灰色体の場合は、吸収率α、反射率ρ及び透過率τの間に次の関係式が成り立つ
α＋ρ＋τ＝１
【００２３】
この灰色体には、可視域や２．５μｍより短い近赤外は透過するが、２．５μｍよりも長い波長の光をほとんど透過しないガラスのような材料や放射線のほとんどを反射するアルミニウムのような材料、可視域、近赤外域、遠赤外域のほとんどを透過させるプラスチックスのような材料が包含される。
【００２４】
このように、灰色体である材料の吸収、反射、透過は各波長域及び材料の種類により異なるので、灰色体に属する材料の吸収率、反射率、透過率は、熱源となる物体から放射される放射線の波長とその波長に対する灰色体自体の吸収、反射、透過の状態により左右される。
【００２５】
ここでいう放射熱吸収率及び反射率とは、熱源から放射される放射線の波長に対する、その放射線が入射する物体の吸収及び反射の割合である。
なお、ランバートベールの法則によると、放射線例えば光を吸収する材料の厚さを大きくすると、吸収量が増加するし、小さくすると吸収量は減少する。したがって、放射熱吸収量が等しい材料を用いる場合は、その厚さを薄くすることにより放射熱の吸収を減らし、透過率を大きくすることができるので、放射熱吸収の大きい材料であっても放射熱の透過を可能にして、透明層として用いることができる。
【００２６】
次に添付図面に従って、本発明をさらに詳細に説明する。
図１は、本発明断熱板の構造を示す断面図であって、この断熱板は２枚の熱伝導性層１及び２と放射熱反射層３からなる三層構造を有する積層体で構成されている。この図において、第１層すなわち熱伝導性層１は第２層すなわち熱伝導性層２よりも放射熱吸収率及び熱容量の小さい材料からなっており、第３層すなわち放射熱反射層は、第２層２の第１層１に接している側の反対側に積層されている。
【００２７】
第１層１の材料としては、第２層２よりも熱容量が１０％以下、好ましくは５％以下で、熱容量及び放射熱吸収率が６０％以下、好ましくは５０％以下の材料を用いるのがよい。第３層として用いる放射熱反射層３としては、第１層１及び第２層２を透過した放射熱に対し放射熱反射率５％以上、好ましくは１０％以上の材料が好ましい。
【００２８】
本発明断熱板の第２層２の厚さは、０．５〜１０ｍｍの範囲内で選ばれる。第１層１の厚さは、通常１〜１０００μｍの範囲で選ばれるが、保冷倉庫や大型の壁体として用いる場合には、さらに厚くすることができるし、また電子装置などの小型のものに用いる場合には、さらに薄くすることもできる。
第３層すなわち放射熱反射層の厚さは、０．１〜１０００μｍの範囲内で、放射熱反射率が５％以上、好ましくは１０％以上になるように選ばれる。
【００２９】
上記の第２層を構成する材料としては、金属、合金、金属酸化物、セラミックスのような無機材料やプラスチックス、ゴム、木質、パルプのような有機材料が用いられる。
【００３０】
金属、合金の例としては、鉄、アルミニウム、亜鉛、マグネシウム、金、銀、クロム、ゲルマニウム、モリブデン、ニッケル、鉛、白金、ケイ素、チタン、トリウム、タングステンのような各種の単体金属や、炭素鋼、ニッケル鋼、クロム鋼、クロムモリブデン鋼、ステンレス鋼、アルミニウム合金、黄銅、青銅のような各種の合金を挙げることができる。
【００３１】
また、金属酸化物、セラミックスの例としては、アルミナ、シリカ、マグネシア、トリア、ジルコニア、三二酸化鉄、四三酸化鉄、酸化チタン、酸化カルシウム、酸化亜鉛、酸化鉛などの種々の金属酸化物やガラス、陶磁器、焼結炭化ケイ素、焼結窒化ケイ素、焼結炭化ホウ素、焼結窒化ホウ素などの各種のセラミックスなどの無機系物質を挙げることができる。
【００３２】
次に、プラスチックスの例としては、アクリル樹脂、メタクリル樹脂、塩化ビニル樹脂、フッ素樹脂、ケイ素樹脂、ポリエチレン、ポリプロピレン、ポリスチレン、ＡＳ樹脂、ＡＢＳ樹脂、ポリアミド、ポリカーボネート、ポリエチレンテレフタレート、ポリブチレンテレフタレート、酢酸セルロース樹脂、尿素樹脂、メラミン樹脂、フェノール樹脂、不飽和ポリエステル樹脂、エポキシ樹脂、ポリウレタン、ポリビニルブチラール、ポリビニルホルマール、ポリ酢酸ビニル、ポリビニルアルコール、アイオノマー、塩素化ポリエーテル、エチレン・α‐オレフィン共重合体、エチレン・塩化ビニル共重合体、エチレン・酢酸ビニル共重合体、塩素化ポリエチレン、塩化ビニル・酢酸ビニル共重合体、ポリフェニレンオキシド、ポリフェニレンスルフィド、ポリアリールスルホン、ポリエーテル、エーテルケトンなどを、またゴム類の例としては、天然ゴム、ブタジエンゴム、イソプレンゴム、クロロプレンゴム、ブチルゴム、シリコーンゴム、ウレタンゴムなどを挙げることができる。
そのほか、花崗岩、大理石などの各種鉱石類、レンガ、コンクリートなどの各種窯業製品、スギ、マツ、ヒノキなどの各種木材、綿布、麻布、パンヤ布、紙などの各種繊維製品、各種皮革製品なども所望に応じ用いることができる。
【００３３】
これらを第２層として用いる場合、その厚さを厚くしたり、第２層の材料に充てん剤、着色剤などを配合することにより、第１層に対する熱容量及び放射熱吸収率を大きくすることができる。
【００３４】
本発明を構成する第１層の材料としては、赤外線領域において透明なプラスチックスを用いるのが好ましい。一般に、プラスチックスを構成する各原子は、その結合状態により赤外線の吸収波長が異なり、Ｃ−Ｃ、Ｃ−Ｏ、Ｃ−Ｎなどの単結合では７．５〜１２．５μｍ、Ｃ＝Ｃ、Ｃ＝Ｏ、Ｃ＝Ｎ、Ｎ＝Ｏなどの二重結合では５．５〜６．５μｍの範囲、Ｃ≡Ｃ、Ｃ≡Ｎの三重結合では４．５〜５．０μｍの範囲に主な吸収波長が存在し、それ以外の領域においては吸収が少なく透明度が高くなっている。
【００３５】
他方、熱源から放射される赤外線は、前記したように、熱源の温度によりウィーンの変位則から計算される波長を中心として、広い範囲の波長が放射されている。例えば、熱源の温度が約６，０００Ｋである太陽光線から放射される波長は０．３〜２．５μｍであるが、その主波長は約０．５μｍである。１９℃の地温から放射される波長は、約７〜１３μｍであるが、その主波長は約１０μｍである。
【００３６】
したがって、太陽光線のように主波長が約０．５μｍである放射の場合の第１層の材料としては、波長０．３〜２．５μｍの範囲で小さい吸収を示し、透過率の高いプラスチックス、例えば、ポリスチレン、ポリ酢酸ビニル、ポリ塩化ビニル、ポリカーボネート、ポリエチレンテレフタレート、ポリブチレンテレフタレート、酢酸セルロース、ジアリルフタレート樹脂、尿素樹脂、メラミン樹脂、ポリビニルブチラール、塩化ビニル・酢酸ビニル共重合体、エチレン・α‐オレフィン共重合体、エチレン・塩化ビニル共重合体、アクリル酸・塩化ビニル共重合体、ポリメチルペンテン、ポリテトラフルオロエチレン、ポリクロロトリフルオロエチレン、ポリビニルピロリドン、ポリメタクリル酸メチル、メタクリル酸メチル・スチレン共重合体、ポリメタクリル酸ブチル、ナイロン６６、エポキシ樹脂、ケイ素樹脂、ブタジエン・スチレン樹脂、ポリスルホン、ポリフッ化ビニリデン、ＭＢＳ樹脂、ポリブタジエン、ポリエーテルスルホンなどの各種物質やこれらの混合物を用いるのが好ましい。
【００３７】
また、熱源の温度が２００℃以下で、その主波長が約６μｍ以下となるような放射の場合には、波長４μｍより長い領域で小さい吸収を示し、透過率の高いプラスチックス、例えば、ポリエチレン、ポリプロピレン、ポリイソブチレン、ポリスチレン、ポリ酢酸ビニル、エチレン・酢酸ビニル共重合体、ポリビニルアルコール、ポリ塩化ビニル、塩化ビニル・塩化ビニリデン共重合体、ポリアクリロニトリル、ポリビニルピロリドン、ポリアクリル酸、ポリメタクリル酸メチル、メタクリル酸メチル・スチレン共重合体、ポリメタクリル酸ブチル、ケイ素樹脂、ブタジエンゴム、ブチルゴム、クロロプレンゴムやこれらの混合物を用いるのが好ましい。
【００３８】
ランバートベールの法則によると、光を吸収する材料の厚さを厚くすると吸収量が増加し透過量が減少する。そして、その厚さを薄くすると吸収量が減少し透過量が増加する。
例えば、ガラスのように厚さが１ｍｍより厚い場合に、３μｍ以上の波長を吸収する材料でも、その厚さを薄くすると３μｍ以上の波長を透過させることができる。また、アルミニウムのように光をほとんど反射させる材料でも、その厚さを薄くすることにより透過させることができる。
【００３９】
したがって、第１層として使用される材料は、鉄、アルミニウム、亜鉛、マグネシウム、金、銀、クロム、ゲルマニウム、モリブデン、ニッケル、鉛、白金、ケイ素、チタン、トリウム、タングステンのような各種の単体金属や、炭素鋼、ニッケル鋼、クロム鋼、クロムモリブデン鋼、ステンレス鋼、アルミニウム合金、黄銅、青銅のような各種の合金もその厚さを薄くすることにより放射熱の透過を可能とし、用いることができる。
【００４０】
また、アルミナ、シリカ、マグネシア、トリア、ジルコニア、三二酸化鉄、四三酸化鉄、酸化チタン、酸化カルシウム、酸化亜鉛、酸化鉛などの各種の金属酸化物やガラス、陶磁器、焼結炭化ケイ素、焼結窒化ケイ素、焼結炭化ホウ素、焼結窒化ホウ素などの各種のセラミックスなどの無機材料もその厚さを薄くすることにより放射熱の透過を可能とし、第１層に用いることが可能となる。
【００４１】
その他、花崗岩、大理石などの各種鉱石類、レンガ、コンクリートなどの各種窯業製品、スギ、マツ、ヒノキなどの各種木材、綿布、麻布、パンヤ布、紙などの各種繊維製品、各種皮革製品なども所望に応じ用いることができる。
【００４２】
次に、第３層を構成する材料としては、熱源から放射される波長に対し反射率の大きい鉄、アルミニウム、亜鉛、マグネシウム、金、銀、クロム、ゲルマニウム、モリブデン、ニッケル、鉛、白金、ケイ素、チタン、トリウム、タングステンのような各種の単体金属や、炭素鋼、ニッケル鋼、クロム鋼、クロムモリブデン鋼、ステンレス鋼、アルミニウム合金、黄銅、青銅のような各種の合金及びアルミナ、シリカ、マグネシア、トリア、ジルコニア、三二酸化鉄、四三酸化鉄、酸化チタン、酸化カルシウム、酸化亜鉛、酸化鉛などの各種の金属酸化物やガラス、陶磁器、焼結炭化ケイ素、焼結窒化ケイ素、焼結炭化ホウ素、焼結窒化ホウ素などの各種のセラミックスが好ましい。
また、屈折率の異なる透明体を重ね合わせると光の全反射が発生するので、屈折率の異なるプラスチックスを重ね合わせることにより、各領域において透明度の高いプラスチックスも用いることが可能となる。
【００４３】
例えば、第２層として、波長０．３〜２．５μｍの範囲で透過するプラスチックス、例えば、ポリスチレン、ポリ酢酸ビニル、ポリ塩化ビニル、ポリカーボネート、ポリエチレンテレフタレート、ポリブチレンテレフタレート、酢酸セルロース、ジアリルフタレート樹脂、尿素樹脂、メラミン樹脂、ポリビニルブチラール、塩化ビニル・酢酸ビニル共重合体、エチレン・α‐オレフィン共重合体、エチレン・塩化ビニル共重合体、アクリル酸・塩化ビニル共重合体、ポリメチルペンテン、ポリテトラフルオロエチレン、ポリクロロトリフルオロエチレン、ポリビニルピロリドン、ポリメタクリル酸メチル、メタクリル酸メチル・スチレン共重合体、ポリメタクリル酸ブチル、ナイロン６６、エポキシ樹脂、ケイ素樹脂、ブタジエン・スチレン樹脂、ポリスルホン、ポリフッ化ビニリデン、ＭＢＳ樹脂、ポリブタジエン、ポリエーテルスルホンなどやこれらの混合物を用いた場合、第３層の反射層として第２層に対し、屈折率が小さく、波長０．３〜２．５μｍの範囲で透過する前記と同様なプラスチックスを用いて反射させることが可能となる。
【００４４】
また、波長が４μｍより長い領域で透過するプラスチックス、例えば、ポリエチレン、ポリプロピレン、ポリイソブチレン、ポリスチレン、ポリ酢酸ビニル、エチレン・酢酸ビニル共重合体、ポリビニルアルコール、ポリ塩化ビニル、塩化ビニル・塩化ビニリデン共重合体、ポリアクリロニトリル、ポリビニルピロリドン、ポリアクリル酸、ポリメタクリル酸メチル、メタクリル酸メチル・スチレン共重合体、ポリメタクリル酸ブチル、ケイ素樹脂、ブタジエンゴム、ブチルゴム、クロロプレンゴムなどの各種物質やこれらの混合物を用いた場合、第３層の反射層として第２層に対し、屈折率が小さく、波長が０．４μｍより長い領域で透過する前記と同様なプラスチックスを用いて反射させることが可能となる。
このように、最初から屈折率の異なる物質を組み合わせた透明体の反射層を作成し、第３層として用いることができる。
【００４５】
本発明の断熱板の形状には、特に制限はなく方形状、円形状、筒状、半球状、球状など任意の形状に形成できるし、また、波形表面、凸凹表面、突起状表面などの表面形状に加工されたものでもよい。
【００４６】
本発明における断熱板を製造するには、あらかじめフィルム状又はシート状に形成した各層の材料を熱融着や接着、粘着などにより貼着する方法、プラスチックスを適当な溶剤に溶かして慣用されている方法により塗布し、乾燥、固化させる方法、化学蒸着、真空蒸着、めっき、無電解めっきなどで固着する方法など、他の材料に積層するのに慣用されている方法の中から任意に選択して積層する。また、所定の材料を分散、溶解などのこれまで慣用されている方法により処理して上記と同様の方法を用いて積層する。そして、従来からある構築物や建物などに後から積層することもでき、積層した断熱板を用いて、構築物や建物などを作ることもできる。
【００４７】
図１には、第１層、第２層、第３層が単体の場合の例を示したが、本発明においては、第１層、第２層又は第３層或いはその３層すべてを複合体に構成することもできる。この場合において第１層と第２層は、高温帯域側の熱容量及び放射熱吸収を低温帯域側のもののそれらよりも小さくするという関係が満たされていることが必要である。そして、この場合、最も高温帯域側に表面を形成する第１層は、第２層が第３層に接する層の熱容量の１０％以下、好ましくは５％以下の熱容量と、第２層が第３層に接する層の放射熱吸収の６０％以下、好ましくは５０％以下の放射熱吸収を有するように構成するのが望ましい。
【００４８】
また、第３層の反射層は、第２層に接する層の反射率が最も低温帯域側に位置する表面を形成する層の反射率より小さくするという関係が満たされていることが必要である。そして、この場合、第１層、第２層を透過した放射熱を５％以上、好ましくは１０％以上反射するように構成するのが望ましい。
【００４９】
本発明の断熱板は、従来の発泡スチレン、発泡ウレタンなどの断熱材及び放射熱吸収、放射熱反射のある材料とも併用することができる。
通常、高温帯域から対流、放射により伝達される熱は、最初に壁面の高温帯域側表面に伝達される。次に、高温帯域側表面に伝達された熱は、隔壁を熱伝導により低温帯域側表面に伝達される。そして、壁面の低温帯域側表面から低温帯域に対流、放射により伝達される。
【００５０】
透明層の熱容量が基体の熱容量の１０％以下であり、透明層の放射熱吸収が基体の放射熱吸収の６０％以下である断熱板の場合、基体の放射熱吸収が大きいと基体表面から低温帯域に放射で放熱される量が多くなり基体の温度が低下してしまう。その結果、透明層と基体の温度勾配がなくなり断熱効果が減少してしまう。
【００５１】
本発明の断熱板を高温帯域と低温帯域の間に設けた隔壁の一部又は全部に断熱板の第１層が高温帯域側になるように配置すると、高温帯域から照射される放射熱は、第１層を透過して第２層に吸収される。そして、第１層及び第２層を透過した放射熱は、第３層で反射され第２層で再度吸収される。その結果、第２層が吸収する放射熱は、第３層がない場合より放射熱の吸収量が増加し、温度上昇が大きくなる。そして、吸収率の大きい第２層（透明層の熱容量が基体の熱容量の１０％以下であり、透明層の放射熱吸収が基体の放射熱吸収の６０％以下である断熱板の基体）から低温帯域に放射による放熱が軽減され、第２層の温度が第１層に対し常に高く保持されるようになり、逆方向に形成された温度勾配が維持され、断熱効果を向上できる。
【００５２】
前記で示したように、放射熱は第１層を透過して第２層で吸収される。しかし、対流熱伝達は、空気などの媒体の移動により伝達されるので、第１層の表面に移動する。第１層の表面に移動した対流熱は、伝導で隔壁を移動するが、隔壁内部で逆方向に形成された温度勾配により伝達されなくなる。
このようにして、対流、伝導、放射による熱伝達を防止させ、住宅、保冷倉庫の屋根材、天井材、壁材、床材、各種容器などの断熱材として効果的に利用することができる。
【００５３】
【実施例】
次に実施例により本発明をさらに詳細に説明する。
【００５４】
実施例１
厚さ５ｍｍの発泡スチロール板で一面のみを開放した立方体上の箱（５０×５０×５０ｃｍ）３個を作成し、それぞれの箱の開口部の１個に厚さ５０μｍのポリエステルフィルム（熱容量１６．６ｃａｌ／℃、放射熱吸収率５５％）のみからなるもの（Ａ）と１個にポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を厚さ５μｍ（熱容量０．５ｃａｌ／℃、放射熱吸収率１８％）積層させたもの（Ｂ）及び１個にポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を積層させた反対側にＡｌ₂Ｏ₃を８Å蒸着（反射率１１．５％）させたもの（Ｃ）を、メタクリル酸メチル−アクリル酸エチル−スチレン共重合体が高箱内側（高温側）になるように取り付けた。
次に、これらの箱を外部から赤外ヒーターで加熱して、内部温度を６０℃まで上昇させた後、１６℃の冷却空気を送風しながら、内部温度経時的変化を調べた。その結果を破線（Ａ）と一点鎖線（Ｂ）と実線（Ｃ）のグラフとして図２に示す。
【００５５】
実施例２
鉄筋コンクリート造３階建の建物の２階部分において、容積４２ｍ³の縦１．２ｍ、横０．９ｍの長方形の窓がある隣り合わせた同一の部屋３個を用意し、その窓ガラスの室内側に厚さ５０μｍのポリエステルフィルム（熱容量１６．６ｃａｌ／℃、放射熱吸収率５５％）とガラスを粘着材で積層したもの（Ａ）とポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を厚さ５μｍ（熱容量０．５ｃａｌ／℃、放射熱吸収率１８％）積層させたもののポリエステルフィルム面とガラスを粘着材で積層したもの（Ｂ）とポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を積層させた反対側にＡｌ₂Ｏ₃を８Å蒸着（反射率１１．５％）させたもののＡｌ₂Ｏ₃を蒸着させた面とガラスを粘着材で積層したもの（Ｃ）をガラス面が外気になるように取り付け、夜間において、２３００ｋｃａｌ／ｈｒの温風暖房機で２０℃に上昇させた後、室内の温度低下の経時的変化を測定した。この結果を表１に示す。
【００５６】
【表１】

【００５７】
この表から、ポリエステルフィルムだけの場合はその室内温度が１０．５℃低下し、ポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を積層させた（Ｂ）の場合は、７．８℃低下したが、Ａｌ₂Ｏ₃を蒸着させた断熱板（Ｃ）は４．７℃の低下にとどまっていることが分る。
【００５８】
実施例３
室温を２０℃、湿度５０％に設定した部屋で、縦０．３５ｍ、横０．５５ｍ、奥行き０．６０ｍの一面が開放した同一の冷蔵庫３個を用意し、実施例２で作成したものを縦０．３５ｍ、横０．５５ｍの大きさに切断し、ガラス面が冷蔵庫側（低温側）になるように取り付け、冷蔵庫内の温度を−１０℃に保ち、表面に発生する結露の状態を観測した。この結果を表２に示す。
【００５９】
【表２】

【００６０】
この表から、ポリエステルフィルムだけの場合は、結露の流滴が３０分後、ポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を積層させた（Ｂ）の場合は、９０分後に発生し、Ａｌ₂Ｏ₃を蒸着させた断熱板（Ｃ）は１８０分後においても結露の流滴が発生しないことから、断熱効果が大きいことが分る。
【００６１】
実施例４
実施例１で用いたのと同じ発泡スチロール製の立方体上の箱を５個用意した。実施例２と同じポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を厚さ５μｍ（熱容量０．５ｃａｌ／℃、放射熱吸収率１８％）積層させた反対側に、ＳｉＯ₂を水系のアクリル樹脂に分散させたものを塗布し、それぞれ異なった反射率の層を形成した断熱板を、ＳｉＯ₂を積層させた面とガラスを粘着材で積層したもの（Ｃ）をガラス面が外側（低温側）になるように取り付けた。次いで、それぞれの内部に黒布で覆った６０Ｗ−赤外線ランプを配置し、加熱しながら、その内部温度の経時的変化を調べた。その結果を表３に示す。
【００６２】
【表３】

【００６３】
この表から、第１層と第２層の熱容量と放射熱の割合が同一のものでも、反射率が大きくなると内部温度が高くなり断熱効果が優れていることが分る。
【００６４】
実施例５
実施例２と同じポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を厚さ５μｍ（熱容量０．５ｃａｌ／℃、放射熱吸収率１８％）積層させた反対側にＣｒを蒸着させ（反射率７０．５％）、Ｃｒ蒸着面とガラス面を粘着剤で積層したものを作成し、実施例２と同様の実験を行った。その結果を表４に示す。
【００６５】
【表４】

【００６６】
この表から、ポリエステルフィルムだけの場合はその室内温度が１１．９℃低下し、ポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を積層させた場合は、９．２℃低下したが、Ｃｒを蒸着させた断熱板は４．２℃の低下にとどまっていることが分る。
【００６７】
実施例６
実施例２と同じ方法で作成した試料（Ａ）、（Ｂ）、（Ｃ）を作成し、ガラス面の変わりに厚さ１ｍｍの鉄板に粘着剤で実施例２と同様に積層し、実施例２と同様の実験を行った。結果を表５に示す。
【００６８】
【表５】

【００６９】
この表から、ポリエステルフィルムだけの場合はその室内温度が１３．３℃低下し、ポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を積層させた場合は、１１．１℃低下したが、Ａｌ₂Ｏ₃を蒸着させた断熱板は６．２℃の低下にとどまっていることが分る。
【００７０】
実施例７
厚さ１００μｍの塩化ビニルフィルム（熱容量９．５６ｃａｌ／℃、放射熱吸収率７８％）とガラスを粘着材で積層したもの（Ａ）とポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を厚さ５μｍ（熱容量０．５ｃａｌ／℃、放射熱吸収率１８％）積層させたものの塩化ビニルフィルム面とガラスを粘着材で積層したもの（Ｂ）と塩化ビニルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を積層させた反対側にＳｉＯ₂を水系のアクリル樹脂に分散させたものを塗布（反射率９．８％）させたものをＳｉＯ₂塗布面とガラスを粘着材で積層したもの（Ｃ）をガラス面が外気側（低温側）になるように取り付け、夜間において、２３００ｋｃａｌ／ｈｒの温風暖房機で２０℃に上昇させた後、室内の温度低下の経時的変化を測定した。この結果を表６に示す。
【００７１】
【表６】

【００７２】
この表から、ポリエステルフィルムだけの場合は、その室内温度が１１．２℃低下し、ポリエステルフィルムにメタクリル酸メチル−アクリル酸エチル−スチレン共重合体を積層させた場合は８．５℃低下したが、ＳｉＯ₂を水系のアクリル樹脂に分散させたものを塗布させた断熱板は５．０℃の低下にとどまっており、断熱効果が大きいことが分る。
【００７３】
【発明の効果】
本発明によると、従来の透明層の熱容量が基体の熱容量の１０％以下であり、透明層の放射熱吸収が基体の放射熱吸収の６０％以下である断熱板の基体の材料として、放射熱透過性のある物質も用いることが可能となり、住居、保冷倉庫、保冷車両、保温容器などの隔壁用として好適に利用できる。
【図面の簡単な説明】
【図１】 本発明断熱板の構造例を示す断面図。
【図２】 本発明断熱方法における経時的温度変化を示すグラフ。
【符号の説明】
１ 第１層
２ 第２層
３ 第３層（放射熱反射層）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel heat insulating plate, and more particularly to an improved heat insulating plate composed of a composite layer using thermal gradient and a heat insulating method using the same.
[0002]
[Prior art]
In general, in a sealed space such as a building or a container, various inorganic or organic heat insulating materials are used to block heat transfer from the inside to the outside and from the outside to the inside.
[0003]
As the inorganic heat insulating material, for example, glass fiber, glassy heat insulating material such as foam glass, mineral heat insulating material such as asbestos, mineral wool, perlite, vermiculite, porous silica, porous alumina, alumina, magnesia, zirconia, There are ceramic insulation materials such as refractory bricks, carbon insulation materials such as graphite and carbon fiber, and organic insulation materials include foamed plastics such as foamed polyethylene, foamed polystyrene, and foamed polyurethane, wood boards, cork. , Natural material insulation such as plant fibers.
In addition, an air layer heat insulating material is also known in which low thermal conductivity of a gas such as air is used and sealed in aluminum, paper, or plastics.
[0004]
These heat insulating materials themselves use materials with low thermal conductivity to suppress heat transfer, or enclose substances with low thermal conductivity such as gas in pores and voids to suppress heat transfer. Is.
[0005]
By the way, it is generally known that if the density is reduced by increasing the number of pores and voids for the porous heat insulating material, the thermal conductivity is reduced and the heat insulation efficiency is improved. Since strength decreases and heat transfer due to gas convection increases due to temperature rise, there is a natural limit to increasing pores and voids.
[0006]
On the other hand, it is conceivable to increase the thickness of the heat insulating material to enhance the heat insulating effect, but there are practical disadvantages such as a high cost accompanying an increase in the amount of heat insulating material used and an increase in capacity for heat insulating.
[0007]
In order to overcome the disadvantages of the conventional heat insulating material, the present inventors previously arranged a heat insulating plate based on a completely new theory, that is, placed between the high temperature zone and the low temperature zone, A heat insulating plate for blocking heat radiation to the zone, comprising a composite of an opaque thermally conductive substrate located on the low temperature zone side and a thermally conductive transparent layer located on the high temperature zone side, A heat insulating plate characterized in that the heat volume and radiant heat absorption are smaller than the heat volume and radiant heat absorption of the substrate, and a heat insulating method using the same have been proposed (Japanese Patent No. 2624575).
[0008]
However, depending on the conditions of the heat conductive substrate and the low temperature zone, this heat insulating plate may have a large absorption rate of the heat conductive substrate and increase the emission of radiant heat. If it becomes significant, the temperature of the heat conductive substrate is lowered, and the temperature gradient between the heat conductive transparent layer and the heat conductive substrate becomes small, and there is a drawback that the heat insulation effect is reduced.
[0009]
[Problems to be solved by the invention]
The present invention comprises a thermally conductive substrate carrying a transparent layer, and the heat capacity and radiant heat absorption rate of the transparent layer are smaller than the heat capacity and radiant heat absorption rate of the substrate. It was made for the purpose of preventing heat conduction by convection, conduction and radiation from the high temperature zone side to the low temperature zone side by preventing heat dissipation and increasing the temperature difference in the opposite direction between the transparent layer and the substrate. is there.
[0010]
[Means for Solving the Problems]
The present inventors have a heat insulating plate composed of a first layer arranged on the high temperature zone side and a second layer arranged on the low temperature zone side and having a larger heat capacity and radiant heat absorption rate than the first layer. In this case, the third layer for reflecting the radiant heat transmitted through the first layer and the second layer is further provided on the low temperature zone side, so that heat transfer by convection, conduction and radiation from the high temperature zone side to the low temperature zone side can be performed. Based on this finding, the inventors have found that it can be efficiently blocked.
[0011]
  That is, the present invention provides a composite heat insulating plate that is disposed between a high temperature zone and a low temperature zone to block heat dissipation from the high temperature zone to the low temperature zone, and a first layer located on the high temperature zone side and a low temperature adjacent thereto. Located on the band side,Radiant heat absorption rate is 55% or lessThe second layer having radiant heat permeability is formed so that the heat capacity and radiant heat absorption rate of the latter are larger than the heat capacity and radiant heat absorption rate of the former, and the first layer and the second layer are further disposed on the low temperature zone side. A heat insulating plate characterized by laminating a third layer for reflecting radiant heat transmitted through the layer, and a heat conductive first layer, and radiant heat absorption larger than the radiant heat absorption and heat capacity of the first layer And has heat capacity,Radiant heat absorption rate is 55% or lessA composite heat insulating plate comprising a heat conductive second layer having radiant heat permeability and a third layer that reflects radiant heat transmitted through the first layer and the second layer is provided between the high temperature zone and the low temperature zone. The heat insulating method is characterized in that the layer is disposed so as to be positioned on the high temperature zone side.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In general, heat transfer is performed by a combination of radiant heat transfer, heat transfer and convective heat transfer.
The radiant heat Q therein is expressed by the following equation, which can be conducted even in a vacuum.
Q = σ · ε · (100 / T)^Four
Where σ is the Stefan-Boltzmann constant, ε is the emissivity of the object, and T is the absolute temperature of the object.
[0013]
And the heat Q transferred by convection and conduction through the heat insulating plate₁Can be expressed as:

Where α₁Is the heat transfer coefficient of the fluid in the high temperature zone, Tr is the temperature of the fluid in the high temperature zone, T₁Is the surface temperature of the heat insulating plate on the high temperature zone side, λ is the thermal conductivity of the heat insulating plate, L is the thickness of the heat insulating plate, T₂Is the surface temperature on the low-temperature zone side of the insulation plate, α₂Is the heat transfer coefficient of the fluid in the low temperature zone, T₀Is the temperature of the fluid in the cold zone.
[0014]
Also, heat Q due to radiation through the heat insulating plate₂Is transmitted from the object and fluid in the high temperature zone to the wall surface on the high temperature zone side by radiation and conduction, and then transferred to the wall surface on the high temperature zone side by heat conduction, and then from the wall surface on the low temperature zone side to the object and fluid in the low temperature zone Transmitted by radiation. This is expressed as follows.
[0015]
    Q₂= Σ × f (ε₁) X [((100 / Tr)^Four-(100 / T₁)^Four]
        = Λ / L (T₁-T₂)
        = Σ × f (ε₂) X [(100 / T₂)^Four-(100 / T₀)^Four]
  Where σ is the Stefan-Boltzmann constant and f (ε₁) Is the radiation coefficient of radiant heat transfer between objects in the hot zone, Tr is the temperature of the object or fluid in the hot zone, T₁Is the surface temperature of the heat insulating plate on the high temperature zone side, λ is the thermal conductivity of the heat insulating plate, L is the thickness of the heat insulating plate, T₂Is the surface temperature of the heat insulating plate on the low temperature zone side, f (ε₂) Is the radiation coefficient of radiation heat transfer between objects in the low temperature zone, T₀Islow temperatureThe temperature of the object or fluid in the zone.
  In this case, radiant heat transfer and convective heat transfer are handled separately, but actually heat transfer by radiation and convection is performed simultaneously.
[0016]
According to Kirchhoff's law, the absorptivity and emissivity are equal. Therefore, if the radiant heat absorptivity of the wall surface is large, the radiation coefficient of radiant heat transfer in the high temperature zone and low temperature zone increases, and the amount of radiant heat transfer Will increase. In addition, when the radiation coefficient between the object in the high temperature zone and the fluid and the object that is the wall surface is small, and the radiation coefficient of the radiant heat transfer between the object in the low temperature zone and the fluid and the object that is the wall surface is large, the temperature of the object that becomes the wall surface is descend.
[0017]
Therefore, in the heat insulating plate in which the heat capacity of the transparent layer is 10% or less of the heat capacity of the substrate and the radiant heat absorption of the transparent layer is 60% or less of the radiant heat absorption of the substrate, It becomes difficult to form a temperature gradient between the heat conductive transparent layer and the heat conductive substrate.
[0018]
By the way, in order to prevent the temperature decrease of the heat conductive substrate, the radiant heat transmitted through the first layer, that is, the heat conductive transparent layer, and the second layer, that is, the heat conductive substrate layer, is reflected, What is necessary is just to always form the temperature gradient between a heat conductive transparent layer and a heat conductive base | substrate layer by increasing absorption of a radiant heat.
[0019]
  The heat capacity here is a parameter defined by the following equation when this is represented by q.
    q = V · d · c
      = W · c
  Where c is specific heat (cal / g · K), d is density (g / cm^Three), V is the total volume (cm^Three), W is the total mass (g).
  Therefore, the heat capacity q is the specific heat c, density d and totalmassIt can be seen that the parameter is proportional to W.
[0020]
This specific heat c is unique to each material constituting the object, and its numerical value varies depending on the temperature. Usually, a value obtained by measuring at room temperature using a conventional specific heat measuring device is used. The heat capacity can be arbitrarily adjusted by changing the total volume by increasing / decreasing the thickness per unit area, for example, even if a material having the same specific heat and density is used.
In addition, as a radiant heat absorption rate and a radiant heat reflectance here, the numerical value measured with the infrared spectrophotometer (FTIR) can be used.
[0021]
On the other hand, radiation emitted from an object serving as a heat source, such as light, emits more energy at an accelerated rate as the temperature rises, and the central wavelength (λ) of the maximum intensity of radiation emitted at a predetermined temperature T (K). Is obtained by the following formula according to Vienna's displacement law.
λ = 2898 / T
[0022]
On the other hand, the radiation incident on the object is completely absorbed when the object is a complete black body, and is totally reflected when the object is a complete white body. And when the object is a completely transparent body, all is transmitted, but when it is a gray body, the following relational expression is established among the absorptance α, the reflectance ρ, and the transmittance τ.
α + ρ + τ = 1
[0023]
This gray body transmits glass in the visible range and near infrared shorter than 2.5 μm, but does not transmit light with a wavelength longer than 2.5 μm, such as glass or aluminum that reflects most of the radiation. Materials, such as plastics that transmit most of the visible, near infrared, and far infrared regions.
[0024]
In this way, the absorption, reflection, and transmission of materials that are gray bodies vary depending on the wavelength range and the type of material, so the absorption rate, reflectance, and transmittance of materials belonging to gray bodies are radiated from the object that is the heat source. It depends on the wavelength of the radiation and the state of absorption, reflection and transmission of the gray body itself for that wavelength.
[0025]
The radiant heat absorption rate and reflectance here are the ratios of absorption and reflection of an object on which the radiation is incident with respect to the wavelength of the radiation radiated from the heat source.
According to Lambert Beer's law, if the thickness of a material that absorbs radiation, for example, light is increased, the amount of absorption increases, and if it is decreased, the amount of absorption decreases. Therefore, when materials with the same amount of radiant heat absorption are used, the thickness can be reduced to reduce the absorption of radiant heat and increase the transmittance. It allows heat transmission and can be used as a transparent layer.
[0026]
Next, the present invention will be described in more detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view showing the structure of the heat insulating plate of the present invention, and this heat insulating plate is composed of a laminate having a three-layer structure including two heat conductive layers 1 and 2 and a radiant heat reflecting layer 3. ing. In this figure, the first layer or heat conductive layer 1 is made of a material having a smaller radiant heat absorption rate and heat capacity than the second layer or heat conductive layer 2, and the third layer or radiant heat reflection layer is the first layer. The two layers 2 are laminated on the side opposite to the side in contact with the first layer 1.
[0027]
As the material of the first layer 1, a material having a heat capacity of 10% or less, preferably 5% or less, and a heat capacity and radiant heat absorption rate of 60% or less, preferably 50% or less, than the second layer 2 is used. Good. As the radiant heat reflecting layer 3 used as the third layer, a material having a radiant heat reflectance of 5% or more, preferably 10% or more with respect to the radiant heat transmitted through the first layer 1 and the second layer 2 is preferable.
[0028]
The thickness of the second layer 2 of the heat insulating plate of the present invention is selected within the range of 0.5 to 10 mm. The thickness of the first layer 1 is usually selected in the range of 1 to 1000 μm. However, when it is used as a cold storage warehouse or a large wall body, it can be made thicker, or it can be made smaller such as an electronic device. If used, it can be made thinner.
The thickness of the third layer, that is, the radiant heat reflecting layer is selected such that the radiant heat reflectance is 5% or more, preferably 10% or more, within a range of 0.1 to 1000 μm.
[0029]
As the material constituting the second layer, inorganic materials such as metals, alloys, metal oxides, and ceramics, and organic materials such as plastics, rubber, wood, and pulp are used.
[0030]
Examples of metals and alloys include various simple metals such as iron, aluminum, zinc, magnesium, gold, silver, chromium, germanium, molybdenum, nickel, lead, platinum, silicon, titanium, thorium, tungsten, and carbon steel And various alloys such as nickel steel, chromium steel, chromium molybdenum steel, stainless steel, aluminum alloy, brass and bronze.
[0031]
Examples of metal oxides and ceramics include various metal oxides such as alumina, silica, magnesia, tria, zirconia, iron sesquioxide, iron tetroxide, titanium oxide, calcium oxide, zinc oxide, and lead oxide. Examples thereof include inorganic substances such as various ceramics such as glass, ceramics, sintered silicon carbide, sintered silicon nitride, sintered boron carbide, and sintered boron nitride.
[0032]
Next, examples of plastics include acrylic resin, methacrylic resin, vinyl chloride resin, fluorine resin, silicon resin, polyethylene, polypropylene, polystyrene, AS resin, ABS resin, polyamide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, acetic acid. Cellulose resin, urea resin, melamine resin, phenol resin, unsaturated polyester resin, epoxy resin, polyurethane, polyvinyl butyral, polyvinyl formal, polyvinyl acetate, polyvinyl alcohol, ionomer, chlorinated polyether, ethylene / α-olefin copolymer , Ethylene / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, chlorinated polyethylene, vinyl chloride / vinyl acetate copolymer, polyphenylene oxide, polyphenyle Sulfide, polyaryl sulfone, polyether, etc. ether ketone, and as examples of rubbers can include natural rubber, butadiene rubber, isoprene rubber, chloroprene rubber, butyl rubber, silicone rubber, and urethane rubber.
In addition, various ores such as granite and marble, ceramic products such as brick and concrete, various wood products such as cedar, pine and cypress, various textile products such as cotton cloth, linen cloth, bread cloth and paper, and various leather products are also desired. It can be used according to.
[0033]
When these are used as the second layer, the heat capacity and the radiant heat absorption rate for the first layer can be increased by increasing the thickness or by adding a filler, a colorant or the like to the material of the second layer. it can.
[0034]
As the material for the first layer constituting the present invention, it is preferable to use plastics transparent in the infrared region. In general, the atoms constituting the plastics have different infrared absorption wavelengths depending on the bonding state. For single bonds such as C—C, C—O, and C—N, 7.5 to 12.5 μm, C = C, Mainly in the range of 5.5 to 6.5 μm for double bonds such as C═O, C═N and N═O, and in the range of 4.5 to 5.0 μm for triple bonds of C≡C and C≡N. Absorption wavelength exists, and in other regions, there is little absorption and transparency is high.
[0035]
On the other hand, as described above, the infrared rays emitted from the heat source are emitted in a wide range of wavelengths centering on the wavelength calculated from the Vienna displacement law depending on the temperature of the heat source. For example, the wavelength radiated from solar rays having a heat source temperature of about 6,000 K is 0.3 to 2.5 μm, but the dominant wavelength is about 0.5 μm. The wavelength emitted from the ground temperature of 19 ° C. is about 7 to 13 μm, but the dominant wavelength is about 10 μm.
[0036]
Therefore, the material of the first layer in the case of radiation having a dominant wavelength of about 0.5 μm, such as sunlight, is a plastic that exhibits low absorption in the wavelength range of 0.3 to 2.5 μm and has high transmittance. For example, polystyrene, polyvinyl acetate, polyvinyl chloride, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, cellulose acetate, diallyl phthalate resin, urea resin, melamine resin, polyvinyl butyral, vinyl chloride / vinyl acetate copolymer, ethylene / α -Olefin copolymer, ethylene / vinyl chloride copolymer, acrylic acid / vinyl chloride copolymer, polymethylpentene, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylpyrrolidone, polymethyl methacrylate, methyl methacrylate Styrene copolymer Polybutyl methacrylate, nylon 66, epoxy resin, silicon resin, butadiene-styrene resins, polysulfone, polyvinylidene fluoride, MBS resin, polybutadiene, to use a variety of materials and mixtures thereof, such as polyether sulfone preferred.
[0037]
In addition, in the case of radiation where the temperature of the heat source is 200 ° C. or less and the dominant wavelength is about 6 μm or less, plastics having a high transmittance, such as polyethylene, exhibiting small absorption in a region longer than the wavelength 4 μm Polypropylene, polyisobutylene, polystyrene, polyvinyl acetate, ethylene / vinyl acetate copolymer, polyvinyl alcohol, polyvinyl chloride, vinyl chloride / vinylidene chloride copolymer, polyacrylonitrile, polyvinyl pyrrolidone, polyacrylic acid, polymethyl methacrylate, It is preferable to use methyl methacrylate / styrene copolymer, polybutyl methacrylate, silicon resin, butadiene rubber, butyl rubber, chloroprene rubber, or a mixture thereof.
[0038]
According to Lambert-Beer's law, increasing the thickness of the material that absorbs light increases the absorption and decreases the transmission. When the thickness is reduced, the amount of absorption decreases and the amount of transmission increases.
For example, when the thickness is greater than 1 mm, such as glass, even a material that absorbs a wavelength of 3 μm or more can transmit a wavelength of 3 μm or more if the thickness is reduced. Further, even a material that reflects almost light, such as aluminum, can be transmitted by reducing its thickness.
[0039]
Therefore, the materials used for the first layer are various simple metals such as iron, aluminum, zinc, magnesium, gold, silver, chromium, germanium, molybdenum, nickel, lead, platinum, silicon, titanium, thorium, tungsten. And various alloys such as carbon steel, nickel steel, chrome steel, chrome molybdenum steel, stainless steel, aluminum alloy, brass and bronze can be used to make radiant heat transparent by reducing its thickness. it can.
[0040]
Also, various metal oxides such as alumina, silica, magnesia, tria, zirconia, iron sesquioxide, iron tetroxide, titanium oxide, calcium oxide, zinc oxide, lead oxide, glass, ceramics, sintered silicon carbide, baked Inorganic materials such as various types of ceramics such as silicon nitride, sintered boron carbide, and sintered boron nitride can also be used for the first layer by reducing the thickness thereof so that radiant heat can be transmitted.
[0041]
In addition, various ores such as granite and marble, ceramic products such as brick and concrete, various wood products such as cedar, pine and cypress, various textile products such as cotton cloth, linen cloth, bread cloth and paper, and various leather products are also desired. It can be used according to.
[0042]
Next, as the material constituting the third layer, iron, aluminum, zinc, magnesium, gold, silver, chromium, germanium, molybdenum, nickel, lead, platinum, silicon having a high reflectivity with respect to the wavelength emitted from the heat source , Various single metals such as titanium, thorium, tungsten, carbon steel, nickel steel, chrome steel, chrome molybdenum steel, stainless steel, various alloys such as aluminum alloy, brass, bronze and alumina, silica, magnesia, Various metal oxides and glass such as tria, zirconia, iron sesquioxide, iron tetroxide, titanium oxide, calcium oxide, zinc oxide, lead oxide, ceramics, sintered silicon carbide, sintered silicon nitride, sintered boron carbide Various ceramics such as sintered boron nitride are preferred.
Further, when transparent bodies having different refractive indexes are overlapped, total reflection of light occurs. Therefore, it is possible to use plastics having high transparency in each region by overlapping plastics having different refractive indexes.
[0043]
For example, as the second layer, plastics that transmit in the wavelength range of 0.3 to 2.5 μm, such as polystyrene, polyvinyl acetate, polyvinyl chloride, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, cellulose acetate, diallyl phthalate resin , Urea resin, melamine resin, polyvinyl butyral, vinyl chloride / vinyl acetate copolymer, ethylene / α-olefin copolymer, ethylene / vinyl chloride copolymer, acrylic acid / vinyl chloride copolymer, polymethylpentene, poly Tetrafluoroethylene, polychlorotrifluoroethylene, polyvinylpyrrolidone, polymethyl methacrylate, methyl methacrylate / styrene copolymer, polybutyl methacrylate, nylon 66, epoxy resin, silicon resin, butadiene / styrene resin When using fat, polysulfone, polyvinylidene fluoride, MBS resin, polybutadiene, polyethersulfone, or a mixture thereof, the refractive index of the third layer is smaller than that of the second layer, and the wavelength is 0.3-2. It is possible to reflect by using the same plastics as described above that transmit in the range of 0.5 μm.
[0044]
Also, plastics that transmit light in the wavelength region longer than 4 μm, for example, polyethylene, polypropylene, polyisobutylene, polystyrene, polyvinyl acetate, ethylene / vinyl acetate copolymer, polyvinyl alcohol, polyvinyl chloride, polyvinyl chloride / vinylidene chloride Various substances such as polymers, polyacrylonitrile, polyvinylpyrrolidone, polyacrylic acid, polymethyl methacrylate, methyl methacrylate / styrene copolymer, polybutyl methacrylate, silicon resin, butadiene rubber, butyl rubber, chloroprene rubber, and mixtures thereof Can be reflected by using the same plastics as those described above that transmit in a region having a small refractive index and a wavelength longer than 0.4 μm with respect to the second layer as the reflective layer of the third layer. .
In this way, a transparent reflective layer combining materials having different refractive indexes from the beginning can be prepared and used as the third layer.
[0045]
The shape of the heat insulating plate of the present invention is not particularly limited, and can be formed in any shape such as a square shape, a circular shape, a cylindrical shape, a hemispherical shape, a spherical shape, and a surface such as a corrugated surface, an uneven surface, or a protruding surface. It may be processed into a shape.
[0046]
In order to manufacture the heat insulating plate in the present invention, a method of sticking the material of each layer previously formed in a film shape or a sheet shape by heat fusion, adhesion, adhesion, or the like, a plastic is dissolved in an appropriate solvent and used conventionally. It is arbitrarily selected from methods commonly used for laminating to other materials, such as a method of applying, drying, solidifying, a method of fixing by chemical vapor deposition, vacuum deposition, plating, electroless plating, etc. And stack. In addition, a predetermined material is processed by a conventionally used method such as dispersion or dissolution, and then laminated using the same method as described above. And it can also laminate | stack on a conventional structure, a building, etc. later, and a structure, a building, etc. can also be made using the laminated heat insulation board.
[0047]
FIG. 1 shows an example in which the first layer, the second layer, and the third layer are single, but in the present invention, the first layer, the second layer, the third layer, or all of the three layers are combined. It can also be configured on the body. In this case, the first layer and the second layer must satisfy the relationship that the heat capacity and radiant heat absorption on the high temperature zone side are smaller than those on the low temperature zone side. In this case, the first layer that forms the surface on the highest temperature zone side has a heat capacity of 10% or less, preferably 5% or less of the heat capacity of the layer in which the second layer is in contact with the third layer, and the second layer is the first layer. It is desirable to have a radiant heat absorption of 60% or less, preferably 50% or less of the radiant heat absorption of the layer in contact with the three layers.
[0048]
In addition, the third reflective layer needs to satisfy the relationship that the reflectance of the layer in contact with the second layer is smaller than the reflectance of the layer forming the surface located on the lowest temperature band side. . In this case, it is desirable that the radiation heat transmitted through the first layer and the second layer is reflected by 5% or more, preferably 10% or more.
[0049]
The heat insulating plate of the present invention can be used in combination with conventional heat insulating materials such as foamed styrene and foamed urethane, and materials having radiant heat absorption and radiant heat reflection.
Usually, heat transferred from the high temperature zone by convection and radiation is first transferred to the high temperature zone side surface of the wall surface. Next, the heat transferred to the surface on the high temperature zone side is transferred to the surface on the low temperature zone side through heat conduction through the partition wall. Then, it is transmitted from the surface of the wall surface on the low temperature zone side to the low temperature zone by convection and radiation.
[0050]
In the case of a heat insulating plate in which the heat capacity of the transparent layer is 10% or less of the heat capacity of the substrate and the radiant heat absorption of the transparent layer is 60% or less of the radiant heat absorption of the substrate, if the radiant heat absorption of the substrate is large, The amount of heat dissipated by radiation in the band increases, and the temperature of the substrate decreases. As a result, the temperature gradient between the transparent layer and the substrate disappears and the heat insulation effect is reduced.
[0051]
When the heat insulating plate of the present invention is arranged so that the first layer of the heat insulating plate is on the high temperature zone side in part or all of the partition wall provided between the high temperature zone and the low temperature zone, the radiant heat irradiated from the high temperature zone is It passes through the first layer and is absorbed by the second layer. And the radiant heat which permeate | transmitted the 1st layer and the 2nd layer is reflected by the 3rd layer, and is absorbed again by the 2nd layer. As a result, the amount of radiant heat absorbed by the second layer increases as compared with the case where there is no third layer, and the temperature rise increases. Then, from the second layer having a high absorption rate (the base of the heat insulating plate in which the heat capacity of the transparent layer is 10% or less of the heat capacity of the base and the radiant heat absorption of the transparent layer is 60% or less of the radiant heat absorption of the base). The heat radiation due to radiation is reduced in the band, the temperature of the second layer is always kept higher than that of the first layer, the temperature gradient formed in the opposite direction is maintained, and the heat insulation effect can be improved.
[0052]
As indicated above, radiant heat is transmitted through the first layer and absorbed by the second layer. However, since convective heat transfer is transferred by movement of a medium such as air, it moves to the surface of the first layer. The convective heat that has moved to the surface of the first layer moves through the partition due to conduction, but is not transmitted by the temperature gradient formed in the opposite direction inside the partition.
In this way, heat transfer due to convection, conduction, and radiation can be prevented, and it can be effectively used as a heat insulating material for houses, roofing materials, ceiling materials, wall materials, floor materials, various containers, etc. for cold storage.
[0053]
【Example】
Next, the present invention will be described in more detail with reference to examples.
[0054]
Example 1
Three cubic boxes (50 × 50 × 50 cm) with only one side opened with a 5 mm thick polystyrene plate, and a polyester film (heat capacity 16.6 cal) having a thickness of 50 μm in one of the openings of each box. (A) consisting only of (/ ° C, radiant heat absorption 55%) and one polyester film with a methyl methacrylate-ethyl acrylate-styrene copolymer having a thickness of 5 μm (heat capacity 0.5 cal / ° C, radiant heat) Absorption rate 18%) Laminated (B) and one polyester film with methyl methacrylate-ethyl acrylate-styrene copolymer laminated on the other side with Al₂O_Three8C (reflectance 11.5%) (C) was attached so that the methyl methacrylate-ethyl acrylate-styrene copolymer was inside the high box (high temperature side).
Next, these boxes were heated from the outside with an infrared heater to raise the internal temperature to 60 ° C., and then the internal temperature change with time was examined while blowing cooling air at 16 ° C. The result is shown in FIG. 2 as a graph of a broken line (A), a chain line (B), and a solid line (C).
[0055]
Example 2
42m capacity on the 2nd floor of a reinforced concrete 3-story building^ThreePrepare three adjacent rooms with rectangular windows of 1.2m in length and 0.9m in width, and a polyester film (heat capacity 16.6cal / ° C, radiant heat) with a thickness of 50μm on the indoor side of the window glass. Absorption rate 55%) and glass laminated with adhesive (A) and polyester film with methyl methacrylate-ethyl acrylate-styrene copolymer 5 μm thick (heat capacity 0.5 cal / ° C., radiant heat absorption rate 18 %) Laminated polyester film surface and glass laminated with adhesive (B) and polyester film with methyl methacrylate-ethyl acrylate-styrene copolymer laminated on the opposite side Al₂O_ThreeOf 8% evaporated (reflectance 11.5%)₂O_Three(C) where the glass-deposited surface and glass laminated with adhesive (C) are attached so that the glass surface becomes outside air, and after raising the temperature to 20 ° C. with a hot air heater of 2300 kcal / hr, The change in temperature with time was measured. The results are shown in Table 1.
[0056]
[Table 1]

[0057]
From this table, in the case of only the polyester film, the room temperature dropped by 10.5 ° C., and in the case of (B) in which the polyester film was laminated with a methyl methacrylate-ethyl acrylate-styrene copolymer, 7.8 Although the temperature decreased, Al₂O_ThreeIt can be seen that the heat-insulating plate (C) on which is deposited is only a drop of 4.7 ° C.
[0058]
Example 3
In a room set at room temperature of 20 ° C and humidity of 50%, three identical refrigerators with one open side of 0.35m in length, 0.55m in width and 0.60m in depth were prepared. Cut to a size of 0.35m in length and 0.55m in width and attached so that the glass surface is on the refrigerator side (low temperature side), keep the temperature in the refrigerator at -10 ° C, and the state of condensation that occurs on the surface Observed. The results are shown in Table 2.
[0059]
[Table 2]

[0060]
From this table, in the case of the polyester film only, the condensation droplets are generated after 30 minutes, and in the case of (B) in which the methyl methacrylate-ethyl acrylate-styrene copolymer is laminated on the polyester film, it occurs after 90 minutes. And Al₂O_ThreeIt can be seen that the heat insulating plate (C) on which is deposited has a large heat insulating effect because no condensation droplets are generated even after 180 minutes.
[0061]
Example 4
  Five boxes on a cube made of the same polystyrene foam used in Example 1 were prepared. The same polyester film as in Example 2 was coated with a methyl methacrylate-ethyl acrylate-styrene copolymer having a thickness of 5 μm (heat capacity 0.5 cal / ° C., radiant heat absorption rate).18%) On the opposite side of the lamination, SiO₂A heat insulating plate in which layers of different reflectivities are formed is coated with SiO 2 dispersed in an aqueous acrylic resin.₂A surface laminated with glass and a glass laminated with an adhesive (C) were attached so that the glass surface was on the outside (low temperature side). Next, a 60 W-infrared lamp covered with a black cloth was placed inside each, and the time-dependent change in the internal temperature was examined while heating. The results are shown in Table 3.
[0062]
[Table 3]

[0063]
From this table, it can be seen that even if the ratios of the heat capacity and radiant heat of the first layer and the second layer are the same, the internal temperature increases and the heat insulation effect is excellent when the reflectance increases.
[0064]
Example 5
  The same polyester film as in Example 2 was coated with a methyl methacrylate-ethyl acrylate-styrene copolymer having a thickness of 5 μm (heat capacity 0.5 cal / ° C., radiant heat absorption rate).18%) Cr was vapor-deposited on the opposite side of the laminated layer (reflectance 70.5%), and a Cr-deposited surface and a glass surface were laminated with an adhesive, and the same experiment as in Example 2 was performed. The results are shown in Table 4.
[0065]
[Table 4]

[0066]
From this table, in the case of the polyester film alone, the room temperature decreased by 11.9 ° C., and when the polyester film was laminated with a methyl methacrylate-ethyl acrylate-styrene copolymer, it decreased by 9.2 ° C. It can be seen that the heat-insulating plate on which Cr is vapor-deposited remains at a decrease of 4.2 ° C.
[0067]
Example 6
Samples (A), (B), and (C) prepared by the same method as in Example 2 are prepared, and laminated in the same manner as in Example 2 with an adhesive on an iron plate having a thickness of 1 mm instead of the glass surface. The same experiment as 2 was performed. The results are shown in Table 5.
[0068]
[Table 5]

[0069]
From this table, in the case of the polyester film alone, the room temperature decreased by 13.3 ° C., and when the polyester film was laminated with methyl methacrylate-ethyl acrylate-styrene copolymer, it decreased by 11.1 ° C. , Al₂O_ThreeIt can be seen that the heat-insulating plate on which is deposited is only 6.2 ° C. lower.
[0070]
Example 7
Methyl methacrylate-ethyl acrylate-styrene copolymer on a 100-μm thick vinyl chloride film (heat capacity 9.56 cal / ° C., radiation heat absorption rate 78%) and glass laminated with an adhesive (A) and polyester film 5 μm thick (heat capacity 0.5 cal / ° C., radiant heat absorption rate 18%) laminated with vinyl chloride film surface and glass laminated with adhesive (B) and vinyl chloride film with methyl methacrylate-acrylic acid SiO on the opposite side of the ethyl-styrene copolymer laminated₂SiO2 dispersed in water-based acrylic resin is applied (reflectance 9.8%)₂Attach the coated surface and glass laminated with adhesive (C) so that the glass surface is on the outside air side (low temperature side), and after raising the temperature to 20 ° C. with a 2300 kcal / hr hot air heater, The change over time of the temperature drop in the room was measured. The results are shown in Table 6.
[0071]
[Table 6]

[0072]
From this table, in the case of the polyester film alone, the room temperature decreased by 11.2 ° C., and when the polyester film was laminated with methyl methacrylate-ethyl acrylate-styrene copolymer, it decreased by 8.5 ° C. , SiO₂It can be seen that the heat insulating plate coated with a water-based acrylic resin is kept at a decrease of 5.0 ° C. and has a large heat insulating effect.
[0073]
【The invention's effect】
  According to the present invention, the heat capacity of the conventional transparent layer is 10% or less of the heat capacity of the substrate, and the radiant heat absorption of the transparent layer is 60% or less of the radiant heat absorption of the substrate. Permeable materials can also be used, such as housing, cold storage, and cold storage.vehicleIt can be suitably used for partition walls such as heat insulation containers.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a structural example of a heat insulating plate of the present invention.
FIG. 2 is a graph showing a change in temperature over time in the heat insulation method of the present invention.
[Explanation of symbols]
1 First layer
2 Second layer
3 Third layer (radiant heat reflective layer)

Claims (4)

In the composite heat insulating plate for dissipating heat dissipation from the high temperature zone to the low temperature zone, between the high temperature zone and the low temperature zone, located on the first layer located on the high temperature zone side and the low temperature zone side adjacent thereto, The second layer having radiant heat permeability with a radiant heat absorption rate of 55% or less is formed such that the latter heat capacity and radiant heat absorption rate are larger than the former heat capacity and radiant heat absorption rate, and further A heat insulating plate, wherein a third layer for reflecting radiant heat transmitted through the first layer and the second layer is laminated on the low temperature zone side.   The heat capacity of the first layer is 10% or less of the heat capacity of the second layer, the radiant heat absorption of the first layer is 60% or less of the radiant heat absorption of the second layer, and the radiant heat reflectance of the third layer is 5% or more. The heat insulating board according to claim 1. A heat conductive second layer having a radiant heat absorption and a heat capacity greater than that of the first layer and having a radiant heat absorption rate of 55% or less; A composite heat insulating plate composed of a layer and a third layer that reflects the radiant heat transmitted through the first layer and the second layer is disposed so that the first layer is located on the high temperature zone side between the high temperature zone and the low temperature zone A heat insulation method characterized by:   The heat capacity of the first layer in the heat insulating plate is 10% or less of the heat capacity of the second layer, the radiant heat absorption of the first layer is 60% or less of the radiant heat absorption of the second layer, and the radiant heat reflectance of the third layer is 5%. It is the above, The heat insulation method of Claim 3.

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