JP4546602B2

JP4546602B2 - Heat-insulating layer-forming coating composition, molded product, and method for producing molded product

Info

Publication number: JP4546602B2
Application number: JP2000058012A
Authority: JP
Inventors: 圭一土川; 宏介秋山; 良平永田; 瑠奈中村; 公治佐藤; 有道伊東
Original assignee: Dai Nippon Printing Co Ltd; Tokushu Paper Manufacturing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd; Tokushu Paper Manufacturing Co Ltd
Priority date: 2000-02-29
Filing date: 2000-02-29
Publication date: 2010-09-15
Anticipated expiration: 2020-02-29
Also published as: JP2001240809A

Description

【０００１】
【発明の属する技術分野】
本発明は、種々の分野における断熱性層を形成することのできる断熱性層形成用塗料組成物に関する。本発明の断熱性層形成用塗料組成物は、建築材料、冷蔵庫、保温庫、衣料、もしくはカップラーメンの容器のような食品包材等の分野において、所定の空間と環境との間の熱伝導率を抑制し、環境温度よりも高いかもしくは低い温度を維持するための断熱性層を形成する用途に使用する。
【０００２】
また、本発明は、上記の断熱性層形成用塗料組成物を用いて断熱性層を形成した成形体、特にシート状成形体に関する。
【０００３】
さらに本発明は、上記の断熱性層形成用塗料組成物を用いて、断熱性層を有する成形体、特にシート状成形体を製造する方法に関する。
【０００４】
【従来の技術】
断熱材を、高温状態や低温状態を維持するために使用することは、よく行われており、エネルギーを節約する、高温状態や低温状態が周囲の環境に影響を与えるのを抑制する、あるいはそれらの状態にあるものに直接に接触して火傷や凍傷になるのを防止する等の目的で使用されている。
【０００５】
熱伝導は、電熱、輻射、もしくは対流によって生じるので、断熱材としては、それらの熱伝導を抑制するよう、密度が小さく、かさがあるもので構成されたものを使用し、各種の繊維（絡み合った状態のもの）、もしくは発泡体等で構成することが多い。
【０００６】
しかし、各種の繊維は、対象となる部位に適用するのに手作業の要素が多くなる上、吸湿すると断熱効果が低下し、また、被覆せずに使用すると繊維が飛散して、皮膚を刺激する等の欠点がある。
【０００７】
発泡体は、予め所定の厚みのシートとしておくことにより、取り扱いが各種の繊維を使用する場合よりは容易となるものの、適用部位に直接注入して発泡する現場発泡を除けば、適用部位の形状に合わせることが難しく、また、接触面積が小さいために、他のフィルム等との貼り合わせが難しい等の欠点を有している。
【０００８】
また、各種の繊維、発泡体のいずれにおいても、厚みのごく薄い断熱材を形成するのが難しい。
【０００９】
そこで、本発明者らは、バインダー樹脂、発泡剤、および溶剤を主成分とする発泡性塗料組成物を用いることにより、上記問題点の改善を試みたが、このような発泡性塗料組成物を用いて断熱性層を形成する際には、発泡のための加熱温度もしくは加熱時間の僅かな違いにより、発泡倍率が異なり、発泡の抑制が難しく、発泡を完全に行わせようとすると、過度に発泡が生じる等、所定の発泡倍率で均一に発泡した断熱性層の形成を行うことが困難であった。
【００１０】
【発明が解決しようとする課題】
本発明は、上記実状に鑑みて成し遂げられたものであり、その第一の目的は、適用部位の形状に合わせやすく、断熱層を薄く形成しても十分な断熱効果が得られ、且つ、断熱性能のコントロールが容易な断熱性層形成用塗料組成物を提供することにある。
【００１１】
本発明の第二の目的は、当該塗料組成物を用いて断熱性層を形成した成形体、特に、薄くても断熱効果に優れたシート状成形体を提供することにある。
【００１２】
本発明の第三の目的は、そのような断熱性層を有する成形体、特にシート状成形体を製造する好適な方法を提供することにある。
【００１３】
【課題を解決するための手段】
本発明に係る断熱性層形成用塗料組成物は、必須成分として、バインダー樹脂、閉鎖された空洞を有する中空粒子、及び、繊維を配合してなることを特徴とする。
【００１４】
本発明の断熱性層形成用塗料組成物は閉鎖された空洞を有する中空粒子を含有している。このような中空粒子を用いることによって、断熱性層内に大量の独立気泡を形成することができるので高い断熱性が得られ、しかも、樹脂を発泡させた断熱性層と異なり独立気泡のサイズと量を容易に調節できるので断熱性能のコントロールが容易である。そのため、本発明の塗料組成物を用いて形成した断熱性層は、薄くても優れた断熱性を示す。
【００１５】
また、本発明では、中空粒子を含有する断熱性層の耐破断性、表面強度を高めるために、繊維を塗料組成物中に配合する。断熱性層形成用塗料組成物に繊維を配合することによって、特に、当該塗料組成物を用いて形成した断熱性層を有する単層の又は２層以上からなる積層体の断熱性シートに優れた可撓性、耐屈曲性を付与することができ、当該断熱性シートを適用したい部位の形状に容易に合わせることができるようになる。
【００１６】
前記バインダー樹脂１００質量部に対して、前記中空粒子が２０〜２４０質量部、及び、前記繊維が１０〜２００質量部、配合されていることが好ましい。
【００１７】
前記の中空粒子が、ポリアクリロニトリルで形成され、密度が０．０１〜０．０７ｇ／ｃｍ³の発泡済みマイクロカプセルであることが好ましい。
【００１８】
前記の繊維が、０．３〜５デニールの太さ、及び、１〜７ｍｍの長さを有することが好ましい。
【００１９】
前記の繊維が、熱融着性繊維であることが好ましい。本発明の塗料組成物に熱融着性繊維を配合すると、当該塗料組成物を用いて形成した塗工層又は含浸層のマトリックスに熱融着性繊維が融着し、得られた断熱性層中に三次元ネットワーク構造が形成されるので、断熱性層の可撓性、耐屈曲性を、さらに向上させることができる。
【００２０】
前記熱融着性繊維としては、その表面の少なくとも一部が、熱可塑性樹脂で形成されているものを用いることができ、具体的には、芯鞘構造や組み合わせ構造を有するものを例示できる。その中でも、芯部分がポリエチレンテレフタレートで形成され、且つ、鞘部分がポリエチレン又はポリエチレンテレフタレートで形成されている芯鞘構造の複合繊維が好ましい。
【００２１】
前記の繊維が、軸方向に空洞を有する中空繊維であってもよい。繊維として中空繊維を用いると、断熱性層の気泡量を増加させることができるので、断熱性をさらに向上させることができる。
【００２２】
前記繊維として、温度２０℃、相対湿度９５％における吸湿度が１０％未満のものを用いると、結露を生じる部分に適用した場合に繊維の吸湿を避けることができ、吸湿による耐熱性の低下を防止できる。
【００２３】
本発明の断熱性層塗料組成物を塗工液の状態に調製する場合には、中空粒子が非常に分離しやすいので、塗工液中に増粘剤を溶解又は分散させるのが好ましい。水系の塗工液を調製する場合には、増粘剤として、アルカリ共存型のアクリル樹脂系増粘剤を用いるのが好ましい。
【００２４】
次に、本発明に係る成形体は、必須成分として閉鎖された空洞を有する中空粒子、及び、繊維をバインダー樹脂に配合し固化させてなる断熱性層を備えていることを特徴とする。この成形体の断熱性層は、本発明の上記塗料組成物を用いて形成できる。このような本発明の成形体は、各分野における断熱材として好適に使用できる。
【００２５】
本発明の好ましい一態様によれば、シート状に成形体が提供される。シート状成形体は、断熱性層の少なくとも一面側に、通気性シートを積層してなるシート状積層体とすることができる。前記断熱性層の両面に、通気性シートを積層してもよい。
【００２６】
前記断熱性層の一部が、前記通気性シートの表面から当該通気性シートの内部空隙に入り込んでいる場合には、通気性シートと断熱性層の接着性が向上する。
【００２７】
前記の通気性シートとしては、不織布、特に、太さ０．５〜７デニール、長さ１０〜６０ｍｍの繊維からなる不織布が好ましく用いられる。
【００２８】
また、不織布に熱融着性繊維が含有されている場合には、成形体に熱プレスなどの加熱処理を行うことにより、不織布と断熱性層を熱接着することができる。
【００２９】
不織布として、軸方向に空洞を有する中空繊維からなるものを用いると、成形体の断熱性が更に向上する。
【００３０】
本発明によれば、断熱性及び可撓性に優れる薄いシート状の断熱性成形体を得ることができる。例えば、前記断熱性層の熱伝導率が、０．０１〜０．５Ｗ／ｍ・Ｋのものを得ることが可能であり、また、ＪＩＳＫ７２０３に規定する曲げ試験において、屈曲部分の曲率半径５．０ｍｍで１．０Ｎの荷重を加えても破損しないものを得ることが可能である。
【００３１】
次に、本発明に係る成形体の製造方法は、必須成分として、バインダー樹脂、閉鎖された空洞を有する中空粒子、及び、繊維を溶剤に配合してなる断熱性層形成用塗工液を、通気性シート上に塗布し、形成した塗工層を通気性シートの反対面側から吸引して溶剤を除去し、その後、固化させることにより断熱性層を形成することを特徴とする。
【００３２】
この方法によれば、基材としての通気性シート上に形成した塗工液の層から、短時間のうちに大部分の液体成分を除去できるので、バインダー樹脂の配合割合が少なくても、塗工層のパターン崩れを防止でき、乾燥時間を短縮でき、さらには、中空粒子の分離を防止できる。この方法は、断熱性層の有する単層の又は積層体のシート状成形体を製造するのに適している。
【００３３】
前記の繊維として熱融着性繊維を使用し、且つ、前記の塗工層を乾燥後に加熱することにより前記熱融着性繊維を、前記の塗工層のマトリックスに熱融着させることができる。
【００３４】
前記塗工層の露出面側に、当該塗工層の乾燥前又は乾燥後に第二の通気性シートを重ね、当該塗工層を乾燥させた後に熱プレスすることにより、断熱性層の両面に通気性シートが積層した３層構造の成形体が得られる。
【００３５】
前記断熱性層の形成後、当該断熱性層から前記通気性シートを除去することにより、断熱性層のみからなる単層の成形体を得ることが可能である。
【００３６】
【発明の実施の形態】
（１）断熱性層形成用塗料組成物
本発明の断熱性層形成用塗料組成物は、必須成分として、バインダー樹脂、閉鎖された空洞を有する中空粒子、及び、繊維を配合してなることを特徴とする。当該塗料組成物を何らかの基材シートや基体に適用したり、あるいは断熱性を付与したい場所に直接適用する場合には、通常、当該塗料組成物を溶剤に溶解又は分散させて塗工液を調製し、使用する。また、塗工液には、中空粒子を均一に分散させるために、増粘剤を添加するのが好ましい。
【００３７】
バインダー樹脂としては、次に挙げるような樹脂が使用できる。例えば、ニトロセルロース、酢酸セルロース、酪酢酸セルロース、エチルセルロース、ポリアミド樹脂、塩化ゴム、環化ゴム、ポリ塩化ビニル樹脂、塩化ビニル／酢酸ビニル共重合樹脂、エチレン／酢酸ビニル共重合樹脂、塩素化ポリプロピレン、もしくはアクリル樹脂等の熱可塑性樹脂や、ユリア樹脂、メラミン樹脂、フェノール樹脂、レゾルシノール樹脂、フラン樹脂、エポキシ樹脂、不飽和ポリエステル樹脂、ポリウレタン樹脂、ポリイミド、ポリアミドイミド、ポリベンツイミダゾール、ポリベンゾチアゾール、もしくはポリウレタン樹脂等の熱硬化性樹脂を使用することができ、これらの樹脂は、水または有機溶剤に溶解した樹脂溶液とすることができる。
【００３８】
また、バインダー樹脂としては、スチレンマレイン樹脂、ポリ酢酸ビニル樹脂、アクリル系樹脂、もしくはポリウレタン系樹脂のエマルジョンを使用することができる。
【００３９】
さらにバインダー樹脂としては、天然ゴム、再生ゴム、スチレン−ブタジエンゴム、アクリロニトリル−ブタジエンゴム、クロロプレンゴム、ブチルゴム、ポリスルフィドゴム、シリコーンゴム、ポリウレタンゴム、ステレオゴム（合成天然ゴム）、エチレンプロピレンゴム、もしくはブロックコポリマーゴム（ＳＢＳ、ＳＩＳ、ＳＥＢＳ等）の有機溶剤溶液またはラテックスを使用することができる。
【００４０】
本発明では、閉鎖された空洞を有する中空粒子を塗料組成物中に配合する。本発明において閉鎖された空洞を有する中空粒子とは、外壁により完全に閉鎖された空洞を有するか、又は、完全に閉鎖されていないとしてもバインダー等の他の成分が実質的に侵入できないように外壁により取り囲まれた空洞を有する中空粒子を指す。このような中空粒子を用いることによって、断熱性層内に大量の独立気泡を形成することができるので高い断熱性が得られ、しかも、樹脂を発泡させた断熱性層と異なり独立気泡のサイズと量を容易に調節できるので断熱性能のコントロールが容易である。そのため、本発明の塗料組成物を用いて形成した断熱性層は、薄くても優れた断熱性を示す。独立気泡を確実に得るためには、完全に閉鎖された空洞を有する中空粒子を用いるのが好ましい。
【００４１】
中空粒子としては、種々のものを使用することができる。例えば、有機質の中空粒子としては、アクリル、もしくはアクリルニトリル等のアクリル樹脂、またはポリスチレン樹脂等の合成樹脂を素材とするものが使用できる。また、無機質の中空粒子としては、例えば、工業的に得られるシリカ、アルミナ等を主成分とするもののほか、天然品である火山性のシラスバルーンのようなものを使用できる。また、後述する親水性や疎水性の中空粒子も使用できる。
【００４２】
また、中空粒子としては、マイクロカプセル型の発泡剤を予め発泡させた発泡済みのものを使用することができる。マイクロカプセル型の発泡剤自体は、アクリルニトリル等の樹脂で外壁が構成され、内容物としてイソブタンもしくはネオペンタン等の低沸点炭化水素を含んだものである。
【００４３】
ポリアクリロニトリルを用いてマイクロカプセルを形成すると、マイクロカプセルの外壁を薄く形成でき、密度を非常に小さくできるので好ましい。ポリアクリロニトリルのマイクロカプセル型発泡剤の発泡済みのものとしては、例えば、松本油脂製薬（株）製の中空粒子（品番で、Ｆ−８０ＥＤ、もしくはＦ−８０Ｅ）は、外壁がごく薄く、自身の密度が０．０１ｇ／ｃｍ³〜０．０７ｇ／ｃｍ³と小さいので、断熱性層形成用塗料組成物に配合した際に、熱伝導性の抑制に効果的であり、好ましい。
【００４４】
一般的に入手が可能で、利用できる中空粒子の粒径は、０．３〜３００μｍの範囲であり、これらの中から選択して１種類、または２種類以上を使用する。
【００４５】
中空粒子は比較的丈夫なため、圧縮等の外力にも耐えるが、中空粒子を断熱性層形成用塗料組成物、特にエマルジョン系の塗料組成物に分散させる場合には、攪拌操作の際に塗料組成物中に気泡が入り込みやすい。
【００４６】
気泡は、断熱性を向上させる意味で役立つので、意図的に気泡を発生させたり、もしくは、マイクロカプセル型や分解型等の化学発泡剤等を使用して発泡させ、気泡を発生させてもよい。中空粒子を伴わず、気泡のみでも断熱性を与えることは可能だが、制御の困難性があるので、気泡の過度な発生を起こさせないようにすることが好ましい。
【００４７】
本発明では、中空粒子を含有する断熱性層の耐破断性、表面強度を高めるために、繊維を塗料組成物中に配合する。断熱性層形成用塗料組成物に繊維を配合することによって、特に、当該塗料組成物を用いて形成した断熱性層を有する単層の又は２層以上からなる積層体の断熱性シートに優れた可撓性、耐屈曲性を付与することができ、当該断熱性シートを適用したい部位の形状に容易に合わせることができるようになる。
【００４８】
本発明によれば、熱伝導率が０．０１〜０．５Ｗ／ｍ・Ｋで、しかも、ＪＩＳＫ７２０３に規定する曲げ試験において、屈曲部分の曲率半径５．０ｍｍで１．０Ｎの荷重を加えても破損しないような、断熱性と屈曲性に優れた薄い断熱性層を形成することも可能である。
【００４９】
断熱性層形成用塗料組成物に配合する繊維は、０．３〜５デニールの太さ、及び、１〜７ｍｍの長さを有しているものが好ましい。また、断熱性層形成用塗料組成物中に上記の繊維として熱融着性繊維を配合し、当該塗料組成物を何らかの基体又は適用部位に塗布し、乾燥し、加熱すると、塗工層又は含浸層のマトリックスに熱融着性繊維が融着し、得られた断熱性層中に三次元ネットワーク構造が形成されるので、断熱性層の可撓性、耐屈曲性を、さらに向上させることができる。
【００５０】
熱融着性繊維としては、例えば、ポリエチレン、ポリエチレンテレフタレート、ポリビニルアルコール、エチレン−ビニルアルコール共重合体、ナイロン、塩化ビニル−酢酸ビニル共重合体などの熱可塑性樹脂、または、フェノール樹脂、エポキシ樹脂、尿素樹脂などの熱硬化性樹脂からなる単繊維を使用することができる。また、熱融着性繊維の表面の少なくとも一部が熱溶融しさえすれば周囲のマトリックスに融着できるので、表面の一部が熱可塑性樹脂又は熱硬化性樹脂で、好ましくは熱可塑性樹脂で、形成されている複合繊維を熱融着性繊維として使用してもよい。
【００５１】
また、複合繊維の中でも、当該繊維の表面の一部が比較的溶融しやすい熱融着性樹脂からなる融着性部位を構成すると共に、当該繊維の軸方向に沿って、比較的溶融し難い又は溶融しない材料で形成された非融着性部分を備えたものは、周囲のマトリックスに容易に融着する部分と、加熱によっても溶融又は変形しにくい軸の部分が存在するため、良好な三次元ネットワーク構造を形成することができて好ましい。
【００５２】
そのような複合繊維としては、例えば、加熱処理によって溶融可能な材料で形成された鞘部分と、同じ加熱処理によって鞘部分と比べて溶融し難いか又は溶融しない材料で形成された芯部分とを備える芯鞘構造の複合繊維を例示することができる。より具体的には、溶融温度又は軟化温度が互いに異なる２種の熱可塑性樹脂を用いて、相対的に溶融温度又は軟化温度が高い樹脂で芯部分を形成し、相対的に溶融温度又は軟化温度が低い樹脂で鞘部分を形成した芯鞘構造の複合繊維を用いることができ、その中では、鞘部分がポリエチレン又はポリエチレンテレフタレートで形成され、芯部分がポリエチレンテレフタレートで形成された芯鞘構造の複合繊維が好ましく、鞘部分と芯部分が両方ともポリエチレンテレフタレート（ＰＥＴ）で形成されたものが特に好ましい。
【００５３】
また、加熱処理によって溶融可能な材料で形成された第一の部分と、同じ加熱処理によって第一の部分と比べて溶融し難いか又は溶融しない材料で形成された第二の部分からなる組み合わせ構造または海島構造の複合繊維を用いることもできる。例えば、加熱処理によって溶融可能な材料で形成された第一の部分と、同じ加熱処理によって第一の部分と比べて溶融し難いか又は溶融しない材料で形成された第二の部分とを、繊維の軸方向に沿って並行に配列し一体化したサイドバイサイド構造の複合繊維を例示できる。より具体的には、溶融温度又は軟化温度が互いに異なる２種の熱可塑性樹脂を用いて、第一の部分と第二の部分とを形成したサイドバイサイド構造の複合繊維を用いることができ、その中では、ポリエチレンで形成された第一の部分とポリエチレンテレフタレートで形成された第二の部分とを備えるハーフハーフ構造の複合繊維が好ましい。
【００５４】
断熱性層形成用塗料組成物には、軸方向に空洞を有する中空繊維を配合してもよい。繊維として中空繊維を用いると、断熱性層の気泡量を増加させることができるので、断熱性をさらに向上させることができる。
【００５５】
断熱性層または断熱性層を有する積層体を適用したい部位が、結露を生じ易い場合には、断熱性層の吸湿性が低いほど断熱性能が安定する。そのため、結露を生じ易い部分に断熱性層を適用したい場合には、結露による繊維の吸湿を避けるべく、温度２０℃、相対湿度９５％における吸湿度が１０％未満の繊維を選択して用いるのが好ましい。
【００５６】
溶剤としては、バインダー樹脂を溶解し、中空粒子を分散させるうえで支障がなく、塗料組成物を塗布もしくは含浸などの方法で適用する際に適用対象物を損傷させず、適用後の乾燥や加熱等によって除去が容易なものであれば制約はない。
【００５７】
溶剤もしくは分散剤としては、例えば、ネオペンタン、ｎ−ヘキサン、ｎ−ヘプタン等の脂肪族炭化水素、トルエン、キシレン等の芳香族炭化水素、トリクロロエチレン、パークロロエチレン等のハロゲン化炭化水素、イソプロパノール、ｎ−ブタノール等の脂肪族アルコール、メチルエチルケトン、メチルイソブチルケトン等のケトン類、酢酸エチル、酢酸ｎ−ブチル等のエステル類、もしくはこれら以外の有機溶剤、または水が使用でき、単独もしくは混合して使用される。
【００５８】
増粘剤は、本発明の断熱性層形成用塗料組成物中での中空粒子の浮上または沈降による分離を防止し、中空粒子を均一に分散させる目的で配合するものである。
【００５９】
特に中空粒子として、マイクロカプセル型発泡剤の発泡済みのものを使用する時は、このものの密度が小さいために、塗料組成物中に分散しても浮上してしまうが、増粘剤の配合により分散状態を安定に維持することが可能になる。
【００６０】
水又は水溶性溶剤を用いる溶剤分散系の増粘剤としては、金属石鹸、珪酸質増粘剤、もしくは重合油等が使用でき、前二者は、具体的にはアルミニウムステアレート、ジンクステアレート、もしくはアルミニウムオクテート等の金属石鹸、シリカゲル、ベントナイト、特に有機ベントナイト等の珪酸質増粘剤である。
【００６１】
水分散系の増粘剤としては、珪酸系やベントナイト等の無機質増粘剤、セルロース誘導体、蛋白質系、ポリアクリル酸塩系、もしくはビニル系等の有機質増粘剤が使用でき、有機質増粘剤は、具体的にはメチルセルロース、カルボキシメチルセルロース、もしくはヒドロキシエチルセルロース等のセルロース誘導体、カゼイン、カゼイン酸ナトリウム、カゼイン酸アンモニウム、もしくはアルギン酸ナトリウム等の蛋白質系、ポリアクリル酸ナトリウム、もしくはポリアクリル酸アンモニウム等のポリアクリル酸塩系、またはポリビニルアルコール等のビニル系である。また、アルカリ共存型のアクリル樹脂系増粘剤は、アクリル樹脂溶液として供給され、アルカリ（アンモニア）添加により樹脂が膨潤して増粘効果を生じるもので、塗布後の乾燥でアルカリ（アンモニア）が除かれるため、塗膜となった状態で、増粘剤に起因する影響が残らず、好ましい。
【００６２】
このほかの増粘剤としては、体質顔料と呼ばれる沈降性炭酸カルシウム、硫酸バリウム、アルミナ、クレー、炭酸マグネシウム、石膏、カオリン、もしくは水酸化アルミニウム等の体質顔料も使用できる。
【００６３】
以上の増粘剤は、１種または２種以上を選択して使用することができる。
【００６４】
以上に説明した成分を混合することによって、本発明の断熱性層形成用塗料組成物が調製される。各成分の配合割合は、バインダー樹脂１００重量部に対して、中空粒子を通常は２０〜２４０質量部、より好ましくは５０〜１２０質量部配合し、繊維を通常は１０〜２００質量部、より好ましくは２０〜１００質量部配合する。溶剤は、バインダー樹脂１００重量部に対して、通常は５００〜５０００質量部、より好ましくは１０００〜２０００質量部配合し、当該溶剤に各成分を均一に溶解または分散させる。また、増粘剤は、バインダー樹脂１００重量部に対して、通常は５〜５０質量部、より好ましくは５〜２０質量部配合する。
【００６５】
上記の配合比において、中空粒子が２０質量部未満であると、本発明の塗料組成物を適用して得られる断熱性層の空隙率が低いため、十分な断熱性能が得られないことが多く、一方、２４０質量部を超えると、相対的にバインダー樹脂の割合が少なくなりすぎ、得られる断熱性層の強度が低下することが多い。
【００６６】
また、繊維が１０質量部未満であると、機械的強度が十分に得られないことが多いし、通気性シート上に本発明の断熱性層形成用塗料組成物を塗布して吸引する後述の方法によって断熱性層を形成することも困難である。一方、繊維が２００質量部を超えると、断熱性能が極端に悪化するので、所望の断熱性能が得られないことがある。
【００６７】
また、溶剤が５００質量部未満であると、塗料組成物の流動性が乏しくて塗布や含浸が円滑に行えず、５０００質量部を超えると、塗料組成物の粘度が低くなり、中空粒子が分離しやすいので、塗布若しくは含浸が困難になることが多い。
【００６８】
さらに、増粘剤が５質量部未満であると、増粘効果が不十分なため、中空粒子の浮上または沈降が避けられず、５０質量部を超えると、増粘が過度になって塗布や含浸等に支障が生じる上、相対的にバインダ樹脂の割合が少なくなりすぎ、得られる断熱性層の強度が低下するほか、使用する増粘剤の種類にもよるが、得られる断熱性層中において、中空粒子を取り囲むバインダー樹脂及び増粘剤からなる部分の熱伝導性が上がるため、断熱性能が低下し、好ましくない。
【００６９】
（２）断熱性層を有する成形体、及び、その製造方法
本発明の断熱性層形成用塗料組成物は種々の対象に対して適用可能であるが、工業的には、種々の基材上に塗布するか、含浸性基材に塗布もしくは含浸させ、乾燥等により固化させ、断熱性層を形成する目的で使用するのに適している。断熱性層は、基材上に塗工層の形に形成されたものであってもよいし、含浸性基材に含浸して一体化した含浸層の形に形成されたものであってもよい。断熱性層形成用塗料組成物もしくは含浸性基材の種類によっては、含浸性基材に適用された断熱性層形成用塗料組成物の一部が含浸性基材中に含浸し、残りが含浸性基材の表面に塗膜として残留するような使い方もできる。
【００７０】
本発明の断熱性層形成用塗料組成物の適用対象のうち、塗布により基材上に塗工層を形成し得る基材としては、紙、プラスチック、金属等を素材とするフィルム、シートもしくは板等が挙げられる。
【００７１】
ここで言う「塗工層を形成し得る基材」とは、断熱性層形成用塗料組成物中の溶剤や水等の液体成分が浸透可能であってもよいが、実質的に、断熱性層形成用塗料組成物全体が浸透せず、当該塗料組成物中の固形分が基材上に残留するものを指す。
【００７２】
また、本発明の断熱性層形成用塗料組成物の適用対象のうち、基材内部に含浸層を形成し得る含浸性基材としては、天然繊維、合成繊維、ロックウール、ガラス繊維、炭素繊維等の繊維を原料として製造された不織布、フェルト、布、もしくはこれらの前記繊維を原料として抄造された紙（特に低密度紙）、またはセラミックスシート等が使用できる。
【００７３】
ここで言う「含浸性基材」とは、断熱性層形成用塗料組成物全体が浸透可能なものを指す。ただし、基材の片面側から含浸を行った際に、断熱性層形成用塗料組成物が反対側の面まで到達しないような、厚みの全部には含浸せず、厚みの一部に含浸するものも含める。
【００７４】
本発明の断熱性層形成用塗料組成物を、上記のような適用対象に適用する方法としては、公知の塗布方法もしくは含浸方法を利用する。
【００７５】
塗布方法としては、粘度範囲、塗布量範囲が広いロールコーティング、もしくはバーコーティングが適しているが、その他の方法によってもよい。
【００７６】
含浸方法としては、断熱性層形成用塗料組成物を満たした槽の中に、含浸性基材を浸す方法（いわゆるディッピング）によるか、公知の塗布手段により、含浸性基材の片側もしくは両側から塗布する方法による。断熱性層形成用塗料組成物が基材に十分浸透してから、基材上に残った余分の含浸用塗料を適宜なかき取り装置または除去装置、例えば、サクションドクター、ドクターロール、もしくは丸棒にワイヤーを巻き付けたワイヤーバー等により、余剰分をかき取るか、もしくは除去し、所定の量の断熱性層形成用塗料組成物を含浸性基材に含浸させる。
【００７７】
断熱性層形成用塗料組成物を基材に適用後、塗工層または含浸層を乾燥することによって固化させると、断熱性層が得られる。断熱性層形成用塗料組成物に配合される成分の素材、特にバインダー樹脂の素材によっては、一旦、比較的低温で乾燥させた後に比較的高温で乾燥させて固化したり、比較的低温で乾燥させた後に又は全く乾燥せずに紫外線や電子線の照射により固化してもよい。
【００７８】
また、断熱性層形成用塗料組成物中に熱融着性繊維を配合している場合には、塗工層または含浸層を乾燥等により固化させた後、加熱処理することによって熱融着性繊維を周囲のマトリックスに融着させ、断熱性層に優れた耐破断性、可撓性、耐屈曲性を付与することができる。
【００７９】
本発明の断熱性層形成用塗料組成物は、断熱効果を高めるために可能な限り中空粒子の配合割合を大きくし、バインダー樹脂の配合割合を相対的に少なくするのが望ましいが、バインダー樹脂の量が少ない断熱性層形成用塗料組成物を溶剤に溶解、分散すると、溶剤の配合割合が大きくなるので、流動性が大きくなって塗工層のパターン又は形状のコントロールが困難になり、且つ、乾燥に時間がかかるようになる。従って、断熱性層を形成する際の生産性が悪くなる。また、断熱性層形成用塗料組成物の塗工液の乾燥時間が長いと、乾燥中に中空粒子が塗膜内で分離しやすいので、断熱性層の均一性が悪くなる。本発明の断熱性層形成用塗料組成物の塗工液を用いて含浸層の形の断熱性層を形成する場合には、このような問題は生じないが、塗工層の形の断熱性層を形成したい場合には、このような問題が生じる。
【００８０】
このような問題を避けるために、本発明の断熱性層形成用塗料組成物の塗工液を、通気性シート上に塗布し、形成した塗工層を、通気性シートの反対面側から吸引して溶剤を除去し、その後、乾燥させることにより塗工層の形の断熱性層を形成するのが好ましい。この方法によれば、基材としての通気性シート上に形成した塗工液の層から、短時間のうちに大部分の液体成分を除去できるので、バインダー樹脂の配合割合が少なくても、塗工層のパターン崩れを防止でき、乾燥時間を短縮でき、さらには、中空粒子の分離を防止できる。また、この方法は、断熱性層の有する単層の又は積層体のシート状成形体を製造するのに適している。
【００８１】
この方法で用いられる通気性シートは、当該シートの上に断熱性層形成用塗料組成物の塗工液を塗布して、塗工層の形成面とは反対側の面から吸引処理した時に、塗工層内の溶剤が吸引により除去されると共に、塗工層の全ての或いはほとんどの固形分が当該シート上に残留するものであれば、いかなるものを使用してもよい。
【００８２】
通気性シートの塗工層を乾燥等により固化して断熱性層を形成後、当該断熱性層を剥離して単層の成形体、特にシート状成形体として使用したい場合には、通気性シートと断熱性シートの接着力が弱い方が望ましい。そこで、上述した「塗工層を形成し得る基材」の中から、塗工液の層に含まれている液体成分は吸引により容易に通過できるが、塗工液の層に含まれている実質的に全ての固形分が基材上に残留するものを使用すると、通気性シートの繊維と断熱性層の絡み合いが少ないので、接着力は小さく、剥離しやすい。
【００８３】
一方、通気性シートと断熱性層の積層体を、そのまま断熱性の成形体、特にシート状成形体として使用したい場合には、基材としての通気性シートと断熱性シートの接着力が大きい方が望ましい。そこで、上述した「含浸性基材」の中から、塗工液中の液体成分は吸引により容易に通過できると共に、塗工液の層に含まれている固形成分は、その一部だけが含浸するが、大部分が基材上に塗工層の形で残存するものを使用すると、断熱性層の一部が通気性シートの表面から当該通気性シートの内部空隙に入り込んで、通気性シートの繊維と断熱性層の絡み合いが多くなり、剥離しにくくなる。
【００８４】
断熱性層が剥離し難い通気性シートとしては、具体的には、不織布や合成紙などの中から、目の詰まりすぎていない適度な通気性を有するものを選んで用いるのが好ましい。不織布は、スパンボンド法、カード法、エアーレイ法、湿式法など、いろいろな方法で製造されるが、如何なる方法で製造されたものも用いることができる。
【００８５】
特に、太さ０．５〜７デニールで且つ長さ１０〜６０ｍｍの繊維からなる不織布は、断熱性層形成用塗料組成物の塗工液の液体成分を容易に吸引できると共に、固形成分が適度に含浸して不織布の繊維と断熱性層が十分に絡み合うが、固形成分の大部分は不織布上に残存して塗工層を厚く形成できる。さらに、太さ０．５〜７デニールで且つ長さ１０〜６０ｍｍの繊維からなる不織布は、強度も十分あり、当該不織布上に断熱性層を積層してなるシート状成形体を断熱性を付与したい部位に適用する際に、適用部位の形状に合わせやすい。
【００８６】
熱融着性繊維を含有する不織布の上に本発明の断熱性層形成用塗料組成物を塗布して断熱性層を形成した後で熱プレスなどの加熱処理を行うと、不織布表面の熱融着性繊維が断熱性層に融着し、不織布と断熱性層の接着力が強くなる。熱融着性繊維としては、本発明の断熱性層形成用塗料組成物に配合し得る熱融着性繊維と同じ素材のもの、すなわち各種の熱可塑性樹脂又は熱硬化性樹脂の単繊維、芯鞘構造、組み合わせ構造、海島構造などの複合繊維を用いることができる。その中でも、鞘部分がポリエチレン又はポリエチレンテレフタレートで形成され、芯部分がポリエチレンテレフタレートで形成された芯鞘構造の複合繊維が好ましく、鞘部分と芯部分が両方ともポリエチレンテレフタレート（ＰＥＴ）で形成されたものが特に好ましい。
【００８７】
通気性シートとして、軸方向に空洞を有する中空繊維からなる不織布を用いてもよい。中空繊維からなる不織布を断熱性層の基材として用いると、断熱性層の断熱性に不織布による断熱効果が加わるので、成形体の断熱性が向上する。
【００８８】
断熱性層形成用塗料組成物の塗工液を、上述したような通気性シートのいずれかに塗布して塗工層を形成した後、当該塗工層から液体成分を除去し、さらに乾燥等の手段により固化して断熱性層を形成する。バインダー樹脂の種類によっては、塗工層を乾燥した後で或いは乾燥処理は行わないで、紫外線等の照射により固化する場合もある。
【００８９】
また、断熱性層形成用塗料組成物に熱融着性繊維を配合している場合には、塗工層を乾燥した後で熱プレスすると、熱融着性繊維が周囲のマトリックスに熱融着して３次元ネットワーク構造を形成すると共に、成形体の厚みを調節できる。
【００９０】
このようにして、断熱性層の片面側に通気性シートが積層された成形体が得られる。この成形体は、そのまま断熱性を付与したい場所に貼付等の手段により適用することができる。また、この成形体から通気性シートを剥離して、断熱性層の単層シートを得ることもできる。
【００９１】
さらに、断熱性層の表面強度が足りない場合には、断熱性層の両面に基材シートを積層してもよい。例えば、第一の通気性シートとしての不織布の上に断熱性層形成用塗料組成物の塗工液を塗布して塗工液の層を形成し、第一の通気性シートの反対面側から吸引を行って塗工層の液体成分を除去し、吸引後の塗工層の露出面側に、当該塗工層の乾燥前又は乾燥後に第二の通気性シートとして不織布を重ね、当該塗工層の乾燥後に積層体を熱プレスすることにより、断熱性層の両面に不織布が接合した成形体が得られる。別の方法としては、第一の通気性シートである不織布の上に断熱性層形成用塗料組成物の塗工液を塗布して塗工液の層を形成し、当該塗工液の層の上に第二の通気性シートとして不織布を重ね、両面から吸引処理を行い、乾燥等により固化させ、必要に応じて熱プレスを行うと、断熱性層の両面に不織布が強く接合した成形体が得られる。
【００９２】
【実施例】
以下において本発明を、実施例を通じてさらに詳述する。
【００９３】
（実施例１）
（１）塗料組成物の調製
先ず、水９３重量部を攪拌しながら、ポリアクリロニトリル中空粒子（松本油脂製薬製、品番Ｆ−８０Ｅ）を固形分として２．３重量部、バインダー樹脂としてのアクリル樹脂（中央理化工業製、品番ＥＴ−８４）を固形分として３．８重量部、アルカリ樹脂系増粘剤（中央理化工業製、品番ＦＫ−６１０）を固形分として０．７重量部、及び、２５％アンモニア水０．８重量部を、この順序で投入して、中間調製液を調製した。なお、上記配合割合は、水を除いて固形分ベースである。
【００９４】
この中間調製液（固形分７重量％）に、さらに、当該混合液の固形分４．５ｇに対して、ＰＥＴ−ＰＥＴ芯鞘構造を有し、太さ１．５デニール、長さ５ｍｍの繊維を１．３５ｇを加え、ミキサーにて攪拌混合し、さらに水を加えて固形分濃度１重量％の水系の断熱性層形成用塗料組成物を得た。
【００９５】
（２）断熱性層を有する成形体の製造
網状シートの上に、坪量２０ｇ／ｍ²で且つＰＥＴ−ＰＥＴ芯鞘構造のバインダー繊維を含む不織布を固定し、当該不織布の表面に上記の断熱性層形成用塗料組成物を（塗工量９３．６ｇ／ｍ²）塗布し、同様の不織布を塗工層の上にかぶせた後、得られた積層体の下側から吸引して液体成分を除去した。吸引後、積層体をプレス成形し、１１０℃にてドラム乾燥機で乾燥した。乾燥後、積層体を１５０℃で１０秒間ヒートプレス処理を行った。こうして、断熱性層の両面に不織布を積層した３層構造の成形体を得た。
【００９６】
（実施例２）
網状シートの上に、実施例１で用いたものと同様の不織布を固定し、当該不織布の表面に実施例１で用いたものと同様の断熱性層形成用塗料組成物を同量塗工した後、得られた２層構造の積層体の不織紙側から吸引して液体成分を除去した。吸引後、積層体をプレス成形し、１１０℃にてドラム乾燥機で乾燥した。乾燥後、積層体を１５０℃で１０秒間ヒートプレス処理を行った。こうして、断熱性層の片面に不織布を積層した２層構造の成形体を得た。その後、この成形体から不織紙を剥離し、断熱性層のみからなる単層の成形体を得た。
【００９７】
（実施例３）
実施例２において不織紙を剥離する前の２層構造の成形体についても、下記の試験を行った。
【００９８】
（実施例４）
網状シートの上に、実施例１で用いたものと同様の不織布を固定し、当該不織布の表面に実施例１で用いたものと同様の断熱性層形成用塗料組成物を同量塗工した後、得られた２層構造の積層体の不織紙側から吸引して液体成分を除去した。吸引後、積層体をプレス成形し、１１０℃にてドラム乾燥機で乾燥した。乾燥後、積層体を１５０℃で２０秒間ヒートプレス処理を行った。こうして、断熱性層の片面に不織布を積層した２層構造の成形体を得た。
【００９９】
（実施例５）
断熱性層形成用塗料組成物の塗工量を倍量の１８７．２ｇ／ｍ²に変更したほかは、実施例１と同様にして、断熱性層の両面に不織布を積層した３層構造の成形体を得た。
【０１００】
（実施例６）
断熱性層形成用塗料組成物の塗工量を倍量の１８７．２ｇ／ｍ²に変更したほかは、実施例２と同様にして、断熱性層のみからなる単層の成形体を得た。
【０１０１】
（実施例７）
網状シートの上に、実施例１で用いたものと同様の不織布を固定し、当該不織布の表面に実施例１で用いたものと同様の断熱性層形成用塗料組成物を倍量の１８７．２ｇ／ｍ²塗工した後、得られた２層構造の積層体の不織紙側から吸引して液体成分を除去した。吸引後、積層体をプレス成形し、１１０℃にてドラム乾燥機で乾燥した。乾燥後、積層体を１５０℃で２０秒間ヒートプレス処理を行った。こうして、断熱性層の片面に不織布を積層した２層構造の成形体を得た。その後、この成形体から不織紙を剥離し、断熱性層のみからなる単層の成形体を得た。
【０１０２】
（比較例１）
硬質ポリウレタン（東洋ゴム工業製、品番ソフランＲボード（Ｗ３０）をスライスした断熱性シートについて、上記の各実施例で得られた成形体と共に、下記の試験を行った。
【０１０３】
（試験項目）
下記の試験を行った。結果を下記の表に示す。
【０１０４】
（１）成形体の平均厚さ（ｍｍ）
成形体全体の平均厚さを測定した。すなわち、不織布が積層されている場合には不織布の厚さを含めた平均厚さを測定した。
【０１０５】
（２）密度（ｇ／ｃｍ³）
不織布を含めた成形体の密度を測定した。
【０１０６】
（３）断熱性能（温度差℃）
【０１０７】
先ず、図１に示すように厚さ１．０ｍｍのアルミニウム板（１）の周囲に発泡スチロールの枠（２）を取り付け、アルミニウム板の上に、実施例又は比較例で得られた成形体を２０ｍｍ×２０ｍｍに切り出したサンプル（３）を置いた。それから、アルミニウム板を氷水（４）の上に浮かべ、２３℃、５０Ｒｈの環境下で３５分間放置した。放置後、アルミニウム板の上面（５）の温度と、成形体サンプルの上面の中央部（６）の温度を測定し、温度差の大きいほど断熱性能に優れると評価をした。
【０１０８】
また、実施例１乃至７のサンプルについて熱伝導率を測定したところ、いずれも０．０３〜０．２Ｗ／ｍ・Ｋの範囲であった。
【０１０９】
（４）可撓性
ＪＩＳＫ７２０３に規定する曲げ試験を行い、屈曲部分の曲率半径５．０ｍｍで１．０Ｎの荷重を加えても破損しない場合を合格（○）、破損する場合を不合格（×）と評価した。
【０１１０】
【表１】

【０１１１】
【発明の効果】
本発明の断熱性層形成用塗料組成物は、閉鎖された空洞を有する中空粒子を含有しているので、この塗料組成物を用いて断熱性層を形成すると、断熱性層に大量の独立気泡を形成することができて高い断熱性が得られ、しかも、独立気泡のサイズと量を容易に調節できるので、断熱性能のコントロールが容易である。
【０１１２】
また、本発明の断熱性層形成用塗料組成物は、繊維、好ましくは太さが０．３〜５デニールで且つ長さが１〜７ｍｍの繊維を含有しているので、この塗料組成物を用いて断熱性層を形成すると、断熱性層に優れた耐破断性、表面強度を付与することができる。断熱性層形成用塗料組成物に繊維として熱融着性繊維を配合し、当該塗料組成物の塗工層又は含浸層を加熱処理すると、熱融着性繊維が断熱性層のマトリックスに熱融着して３次元ネットワーク構造を形成するので、断熱性層の耐破断性、表面強度が特に向上する。
【０１１３】
本発明の断熱性層形成用塗料組成物を用いれば、断熱性を付与したい様々な場所に断熱性層を形成することができ、例えば、壁紙等の内装用又は外装用の化粧紙、家電製品の断熱材として利用される。
【０１１４】
特に、本発明の断熱性層形成用塗料組成物は上記したような特性があるので、断熱性層を有する単層の又は積層体のシート状成形体を形成することができる。このシート状成形体は、薄くても断熱性に優れ、しかも、可撓性、耐屈曲性に優れていて、断熱性を付与したい場所の形状に合わせやすい断熱シートとして利用できるので、例えば、窓枠用の化粧紙のように表面に細かい凹凸がある部材を被覆する断熱性化粧紙として好適に利用できる。
【０１１５】
本発明によれば、熱伝導率が０．０１〜０．５Ｗ／ｍ・Ｋで、しかも、ＪＩＳＫ７２０３に規定する曲げ試験において、屈曲部分の曲率半径５．０ｍｍで１．０Ｎの荷重を加えても破損しないような、断熱性と屈曲性に優れた薄い断熱性層を形成できる。
【０１１６】
本発明の断熱性層に、温度２０℃、相対湿度９５％における吸湿度が１０％未満の繊維を用い、断熱性層の吸湿性を小さくすることにより、アルミサッシのような金属製の窓枠は結露を生じる場所に適用する場合でも、断熱性層の吸湿による断熱性の低下が起き難い。
【０１１７】
本発明の断熱性層形成用塗料組成物の塗工液を通気性シートの一面に塗布し、塗工液の層を通気性シートの反対側から吸引して液体成分を除去し、通気性シートの上に残った固形分の塗工層を固化させることによって、断熱性層に通気性シートが積層されたシート状成形体が得られる。
【０１１８】
この方法によれば、基材としての通気性シート上に形成した塗工液の層から、短時間のうちに大部分の液体成分を除去できるので、バインダー樹脂の配合割合が少なくても、塗工層のパターン崩れを防止でき、乾燥時間を短縮でき、さらには、塗工層中の中空粒子の分離を防止できる。
【０１１９】
この方法により得られる断熱性層と通気性シートの積層体を、そのまま断熱材として使用してもよいし、この積層体から通気性シートを剥離して単層の断熱性層を得ることもできる。
【０１２０】
断熱性層と通気性シートの積層体のまま断熱材として使用する場合には、通気性シートとして不織紙、好ましくは太さ０．５〜７デニール、長さ１０〜６０ｍｍの繊維からなる不織布、を使用し、上記方法で断熱性層を形成すると、断熱性層の一部が不織布の内部空隙に入り込んで絡み合うので剥離し難くなるが、塗工液の浸透は少ないので、不織布の上に塗工層を厚く形成できる。また、不織布は強度も十分で耐屈曲性に優れている。
【０１２１】
また、断熱性層を有する成形体の断熱効果を向上させるために、本発明の断熱性層形成用塗料組成物の繊維として中空繊維を用い、或いは、断熱性層に積層する不織布として中空繊維からなる不織布を用いるのが好ましい。
【図面の簡単な説明】
【図１】シート状断熱性成形体の断熱性能を評価する試験装置の概要を説明する図である。
【符号の説明】
１…アルミニウム板
２…発泡スチロールの枠
３…成形体サンプル
４…氷水
５…アルミニウム板の上面
６…成形体サンプルの上面の中央部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coating composition for forming a heat insulating layer capable of forming a heat insulating layer in various fields. The coating composition for forming a heat-insulating layer according to the present invention is used for heat conduction between a predetermined space and the environment in the field of building materials, refrigerators, heat storages, clothing, or food packaging materials such as cup ramen containers. It is used for the purpose of forming a heat insulating layer for suppressing the rate and maintaining a temperature higher or lower than the environmental temperature.
[0002]
Moreover, this invention relates to the molded object which formed the heat insulating layer using said coating composition for heat insulating layer formation, especially a sheet-like molded object.
[0003]
Furthermore, this invention relates to the method of manufacturing the molded object which has a heat insulating layer, especially a sheet-like molded object, using said coating composition for heat insulating layer formation.
[0004]
[Prior art]
Insulation is often used to maintain high and low temperatures, which saves energy, prevents high or low temperatures from affecting the surrounding environment, or It is used for the purpose of preventing burns and frostbite from coming into direct contact with those in the above condition.
[0005]
Since heat conduction is caused by electric heat, radiation, or convection, heat insulation is made of a material that is low in density and bulky so as to suppress heat conduction. Often, it is made up of a foam or the like.
[0006]
However, each type of fiber has many hand-working elements to apply to the target site, and if it absorbs moisture, the heat insulation effect will be reduced.If it is used without being coated, the fiber will scatter and irritate the skin. There are disadvantages such as.
[0007]
Although the foam is easier to handle than using various types of fibers by preliminarily forming a sheet with a predetermined thickness, the shape of the application site is excluded except for in-situ foaming that is directly injected into the application site and foamed. In addition, since the contact area is small, it is difficult to bond to other films.
[0008]
Moreover, it is difficult to form a very thin heat insulating material in any of various fibers and foams.
[0009]
Therefore, the present inventors tried to improve the above problems by using a foamable coating composition mainly composed of a binder resin, a foaming agent, and a solvent. When forming a heat-insulating layer by using, due to slight differences in heating temperature or heating time for foaming, the foaming ratio is different, it is difficult to suppress foaming, and when trying to completely foam, excessively It was difficult to form a heat insulating layer uniformly foamed at a predetermined foaming ratio, such as foaming.
[0010]
[Problems to be solved by the invention]
The present invention has been accomplished in view of the above-mentioned actual situation, and the first object thereof is to easily match the shape of the application site, and a sufficient heat insulating effect can be obtained even if the heat insulating layer is thinly formed. An object of the present invention is to provide a coating composition for forming a heat-insulating layer whose performance can be easily controlled.
[0011]
The second object of the present invention is to provide a molded article in which a heat insulating layer is formed using the coating composition, particularly a sheet-like molded article having an excellent heat insulating effect even if it is thin.
[0012]
The third object of the present invention is to provide a suitable method for producing a molded body having such a heat insulating layer, particularly a sheet-shaped molded body.
[0013]
[Means for Solving the Problems]
The coating composition for forming a heat insulating layer according to the present invention is characterized by blending a binder resin, hollow particles having closed cavities, and fibers as essential components.
[0014]
The coating composition for forming a heat-insulating layer of the present invention contains hollow particles having closed cavities. By using such hollow particles, a large amount of closed cells can be formed in the heat insulating layer, so that high heat insulating properties are obtained, and unlike the heat insulating layer in which the resin is foamed, the size of the closed cells and Since the amount can be easily adjusted, the heat insulation performance can be easily controlled. Therefore, even if the heat insulating layer formed using the coating composition of the present invention is thin, it exhibits excellent heat insulating properties.
[0015]
Moreover, in this invention, in order to improve the fracture resistance of the heat insulation layer containing a hollow particle and surface strength, a fiber is mix | blended in a coating composition. By blending the fiber with the coating composition for forming a heat insulating layer, the heat insulating sheet of a single layer or a laminate composed of two or more layers having a heat insulating layer formed using the coating composition is particularly excellent. Flexibility and bending resistance can be imparted, and it becomes possible to easily match the shape of the part to which the heat insulating sheet is to be applied.
[0016]
It is preferable that 20 to 240 parts by mass of the hollow particles and 10 to 200 parts by mass of the fibers are blended with respect to 100 parts by mass of the binder resin.
[0017]
The hollow particles are formed of polyacrylonitrile and have a density of 0.01 to 0.07 g / cm. ^Three The foamed microcapsules are preferably.
[0018]
It is preferable that the fiber has a thickness of 0.3 to 5 denier and a length of 1 to 7 mm.
[0019]
The fiber is preferably a heat-fusible fiber. When heat-fusible fibers are blended in the coating composition of the present invention, the heat-fusible fibers are fused to the matrix of the coating layer or impregnation layer formed using the coating composition, and the resulting heat insulating layer Since the three-dimensional network structure is formed therein, the flexibility and the bending resistance of the heat insulating layer can be further improved.
[0020]
As said heat-fusible fiber, what has at least one part of the surface formed with the thermoplastic resin can be used, Specifically, what has a core-sheath structure or a combination structure can be illustrated. Among these, a composite fiber having a core-sheath structure in which the core part is formed of polyethylene terephthalate and the sheath part is formed of polyethylene or polyethylene terephthalate is preferable.
[0021]
The fiber may be a hollow fiber having a cavity in the axial direction. When hollow fibers are used as the fibers, the amount of bubbles in the heat insulating layer can be increased, so that the heat insulating properties can be further improved.
[0022]
If the fiber has a moisture absorption of less than 10% at a temperature of 20 ° C. and a relative humidity of 95%, moisture absorption of the fiber can be avoided when applied to a portion where condensation occurs, and heat resistance is reduced due to moisture absorption. Can be prevented.
[0023]
When the heat insulating layer coating composition of the present invention is prepared in the state of a coating liquid, it is preferable to dissolve or disperse the thickener in the coating liquid because the hollow particles are very easily separated. When preparing an aqueous coating solution, it is preferable to use an acrylic coexisting acrylic resin thickener as a thickener.
[0024]
Next, the molded body according to the present invention is characterized by comprising hollow particles having closed cavities as essential components, and a heat insulating layer obtained by blending fibers into a binder resin and solidifying them. The heat insulating layer of this molded body can be formed using the coating composition of the present invention. Such a molded article of the present invention can be suitably used as a heat insulating material in each field.
[0025]
According to a preferred embodiment of the present invention, a molded body is provided in the form of a sheet. A sheet-like molded object can be made into the sheet-like laminated body formed by laminating | stacking a breathable sheet on the at least one surface side of a heat insulation layer. A breathable sheet may be laminated on both sides of the heat insulating layer.
[0026]
When a part of the heat insulating layer enters the internal space of the air permeable sheet from the surface of the air permeable sheet, the adhesion between the air permeable sheet and the heat insulating layer is improved.
[0027]
As the breathable sheet, a nonwoven fabric, particularly a nonwoven fabric made of fibers having a thickness of 0.5 to 7 denier and a length of 10 to 60 mm is preferably used.
[0028]
Moreover, when the heat-fusible fiber is contained in the nonwoven fabric, the nonwoven fabric and the heat insulating layer can be thermally bonded by performing a heat treatment such as hot pressing on the molded body.
[0029]
When a non-woven fabric made of hollow fibers having a cavity in the axial direction is used, the heat insulating property of the molded body is further improved.
[0030]
ADVANTAGE OF THE INVENTION According to this invention, the thin sheet-like heat insulation molded object which is excellent in heat insulation and flexibility can be obtained. For example, it is possible to obtain a thermal conductivity of the heat insulating layer of 0.01 to 0.5 W / m · K. In a bending test specified in JIS K7203, the radius of curvature of the bent portion is 5 It is possible to obtain one that does not break even when a load of 1.0 N is applied at 0.0 mm.
[0031]
Next, the manufacturing method of the molded body according to the present invention includes, as essential components, a binder resin, hollow particles having closed cavities, and a coating solution for forming a heat insulating layer formed by blending fibers in a solvent, The heat-insulating layer is formed by coating the air-permeable sheet and sucking the formed coating layer from the opposite side of the air-permeable sheet to remove the solvent, and then solidifying.
[0032]
According to this method, since most of the liquid components can be removed from the coating liquid layer formed on the breathable sheet as the base material in a short time, the coating can be applied even if the blending ratio of the binder resin is small. Pattern collapse of the work layer can be prevented, drying time can be shortened, and further, separation of hollow particles can be prevented. This method is suitable for producing a single-layered or laminated sheet-like molded body of the heat insulating layer.
[0033]
A heat-fusible fiber is used as the fiber, and the heat-fusible fiber can be heat-fused to the matrix of the coating layer by heating the coating layer after drying. .
[0034]
On the exposed surface side of the coating layer, the second breathable sheet is stacked before or after the coating layer is dried, and the coating layer is dried and then hot-pressed on both sides of the heat insulating layer. A molded body having a three-layer structure in which breathable sheets are laminated is obtained.
[0035]
After the heat insulating layer is formed, the air-permeable sheet is removed from the heat insulating layer to obtain a single-layer molded body composed of only the heat insulating layer.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
(1) Coating composition for forming a heat insulating layer
The coating composition for forming a heat-insulating layer according to the present invention is characterized in that a binder resin, hollow particles having closed cavities, and fibers are blended as essential components. When the coating composition is applied to any substrate sheet or substrate, or directly applied to a place where heat insulation is desired, the coating composition is usually prepared by dissolving or dispersing the coating composition in a solvent. And use. Moreover, it is preferable to add a thickener to the coating solution in order to disperse the hollow particles uniformly.
[0037]
As the binder resin, the following resins can be used. For example, nitrocellulose, cellulose acetate, cellulose butyrate, ethyl cellulose, polyamide resin, chlorinated rubber, cyclized rubber, polyvinyl chloride resin, vinyl chloride / vinyl acetate copolymer resin, ethylene / vinyl acetate copolymer resin, chlorinated polypropylene, Or thermoplastic resin such as acrylic resin, urea resin, melamine resin, phenol resin, resorcinol resin, furan resin, epoxy resin, unsaturated polyester resin, polyurethane resin, polyimide, polyamideimide, polybenzimidazole, polybenzothiazole, or Thermosetting resins such as polyurethane resins can be used, and these resins can be resin solutions dissolved in water or organic solvents.
[0038]
As the binder resin, an emulsion of a styrene male resin, a polyvinyl acetate resin, an acrylic resin, or a polyurethane resin can be used.
[0039]
Furthermore, the binder resin may be natural rubber, recycled rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, butyl rubber, polysulfide rubber, silicone rubber, polyurethane rubber, stereo rubber (synthetic natural rubber), ethylene propylene rubber, or block. An organic solvent solution or latex of copolymer rubber (SBS, SIS, SEBS, etc.) can be used.
[0040]
In the present invention, hollow particles having closed cavities are blended in the coating composition. In the present invention, the hollow particles having closed cavities have cavities that are completely closed by the outer wall, or other components such as a binder cannot substantially penetrate even if they are not completely closed. It refers to a hollow particle having a cavity surrounded by an outer wall. By using such hollow particles, a large amount of closed cells can be formed in the heat insulating layer, so that high heat insulating properties are obtained, and unlike the heat insulating layer in which the resin is foamed, the size of the closed cells and Since the amount can be easily adjusted, the heat insulation performance can be easily controlled. Therefore, even if the heat insulating layer formed using the coating composition of the present invention is thin, it exhibits excellent heat insulating properties. In order to reliably obtain closed cells, it is preferable to use hollow particles having completely closed cavities.
[0041]
Various hollow particles can be used. For example, as the organic hollow particles, those made of acrylic resin such as acrylic or acrylonitrile, or synthetic resin such as polystyrene resin can be used. As the inorganic hollow particles, for example, industrially obtained silica, alumina or the like as a main component, and natural products such as a volcanic shirasu balloon can be used. Further, hydrophilic or hydrophobic hollow particles described later can also be used.
[0042]
Further, as the hollow particles, foamed particles obtained by previously foaming a microcapsule type foaming agent can be used. The microcapsule type foaming agent itself has an outer wall made of a resin such as acrylonitrile, and contains a low-boiling hydrocarbon such as isobutane or neopentane as a content.
[0043]
The formation of microcapsules using polyacrylonitrile is preferable because the outer wall of the microcapsules can be formed thin and the density can be extremely reduced. As the foamed polyacrylonitrile foaming agent of polyacrylonitrile, for example, hollow particles (part number, F-80ED or F-80E) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. have a very thin outer wall. Density is 0.01g / cm ^Three ~ 0.07g / cm ^Three Therefore, when blended in the heat insulating layer forming coating composition, it is effective in suppressing thermal conductivity, which is preferable.
[0044]
The particle size of the hollow particles that are generally available and can be used is in the range of 0.3 to 300 μm, and one type or two or more types are selected from these.
[0045]
Since the hollow particles are relatively strong, they can withstand external forces such as compression. However, when the hollow particles are dispersed in a heat-insulating layer-forming coating composition, particularly an emulsion-based coating composition, the coating is applied during the stirring operation. Air bubbles easily get into the composition.
[0046]
Bubbles are useful in the sense of improving heat insulation, so bubbles may be intentionally generated or bubbles may be generated by foaming using a chemical foaming agent such as a microcapsule type or a decomposition type. . Although it is possible to provide heat insulation only with bubbles without involving hollow particles, it is difficult to control, so it is preferable not to cause excessive generation of bubbles.
[0047]
In the present invention, fibers are blended in the coating composition in order to increase the fracture resistance and surface strength of the heat insulating layer containing hollow particles. By blending the fiber with the coating composition for forming a heat insulating layer, the heat insulating sheet of a single layer or a laminate composed of two or more layers having a heat insulating layer formed using the coating composition is particularly excellent. Flexibility and bending resistance can be imparted, and it becomes possible to easily match the shape of the part to which the heat insulating sheet is to be applied.
[0048]
According to the present invention, the thermal conductivity is 0.01 to 0.5 W / m · K, and in the bending test specified in JISK7203, a load of 1.0 N is applied with a curvature radius of 5.0 mm at the bent portion. It is also possible to form a thin heat insulating layer excellent in heat insulating properties and bendability so as not to break.
[0049]
The fibers to be blended in the heat insulating layer forming coating composition preferably have a thickness of 0.3 to 5 denier and a length of 1 to 7 mm. In addition, a heat-fusible fiber is blended as the above-mentioned fiber in the heat-insulating layer-forming coating composition, the coating composition is applied to any substrate or application site, dried, and heated to produce a coating layer or impregnation. The heat-fusible fibers are fused to the matrix of the layer, and a three-dimensional network structure is formed in the obtained heat-insulating layer, so that the flexibility and bending resistance of the heat-insulating layer can be further improved. it can.
[0050]
As the heat-fusible fiber, for example, polyethylene, polyethylene terephthalate, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, nylon, thermoplastic resin such as vinyl chloride-vinyl acetate copolymer, or phenol resin, epoxy resin, A single fiber made of a thermosetting resin such as urea resin can be used. Further, since at least a part of the surface of the heat-fusible fiber can be fused to the surrounding matrix as long as it is thermally melted, a part of the surface is a thermoplastic resin or a thermosetting resin, preferably a thermoplastic resin. The formed composite fiber may be used as the heat-fusible fiber.
[0051]
Further, among the composite fibers, a part of the surface of the fiber constitutes a fusible portion made of a heat-fusible resin that is relatively easy to melt, and is relatively difficult to melt along the axial direction of the fiber. Also, those with non-fusible parts formed of non-melting material have good tertiary because there are parts that are easily fused to the surrounding matrix and parts of the shaft that are not easily melted or deformed by heating. An original network structure can be formed, which is preferable.
[0052]
As such a composite fiber, for example, a sheath portion formed of a material that can be melted by heat treatment, and a core portion formed of a material that is difficult to melt or does not melt by the same heat treatment as compared to the sheath portion. The core-sheath composite fiber provided can be exemplified. More specifically, the core portion is formed of a resin having a relatively high melting temperature or softening temperature using two types of thermoplastic resins having different melting temperatures or softening temperatures, and the melting temperature or softening temperature is relatively high. A core-sheath composite fiber in which a sheath part is formed of a low-resin resin can be used, in which a sheath-core composite fiber in which the sheath part is formed of polyethylene or polyethylene terephthalate and the core part is formed of polyethylene terephthalate Fibers are preferred, and those in which both the sheath part and the core part are formed of polyethylene terephthalate (PET) are particularly preferred.
[0053]
Also, a combined structure comprising a first portion formed of a material that can be melted by heat treatment and a second portion formed of a material that is difficult to melt or does not melt by the same heat treatment as compared to the first portion. Alternatively, a composite fiber having a sea-island structure can also be used. For example, a first part formed of a material that can be melted by heat treatment and a second part formed of a material that is difficult to melt or does not melt compared to the first part by the same heat treatment, A side-by-side composite fiber that is arranged in parallel along the axial direction and integrated. More specifically, a composite fiber having a side-by-side structure in which a first portion and a second portion are formed using two types of thermoplastic resins having different melting temperatures or softening temperatures can be used. Then, a half-half-structured composite fiber comprising a first portion made of polyethylene and a second portion made of polyethylene terephthalate is preferable.
[0054]
You may mix | blend the hollow fiber which has a cavity in an axial direction with the coating composition for heat insulation layer formation. When hollow fibers are used as the fibers, the amount of bubbles in the heat insulating layer can be increased, so that the heat insulating properties can be further improved.
[0055]
When the site to which the heat insulating layer or the laminate having the heat insulating layer is to be applied is likely to cause dew condensation, the lower the hygroscopicity of the heat insulating layer, the more stable the heat insulating performance. For this reason, when it is desired to apply a heat insulating layer to a portion where condensation is likely to occur, a fiber having a moisture absorption of less than 10% at a temperature of 20 ° C. and a relative humidity of 95% is selected and used in order to avoid moisture absorption by the condensation. Is preferred.
[0056]
As the solvent, there is no problem in dissolving the binder resin and dispersing the hollow particles, and it does not damage the application object when applying the coating composition by a method such as coating or impregnation, and drying or heating after application There is no limitation as long as it can be easily removed by, for example.
[0057]
Examples of the solvent or dispersant include aliphatic hydrocarbons such as neopentane, n-hexane and n-heptane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as trichloroethylene and perchloroethylene, isopropanol, n -Fatty alcohols such as butanol, ketones such as methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate and n-butyl acetate, or other organic solvents, or water can be used alone or in combination. The
[0058]
The thickener is blended for the purpose of preventing the hollow particles from floating or settling in the coating composition for forming a heat insulating layer of the present invention and dispersing the hollow particles uniformly.
[0059]
In particular, when using foamed microcapsule type foaming agents as hollow particles, the density of this thing is small, so it will float even if dispersed in the coating composition, It becomes possible to maintain a dispersed state stably.
[0060]
As a solvent dispersion thickener using water or a water-soluble solvent, metal soap, siliceous thickener, or polymerized oil can be used, and the former two are specifically aluminum stearate, zinc stearate. Or a siliceous thickener such as a metal soap such as aluminum octate, silica gel, bentonite, especially organic bentonite.
[0061]
As water-dispersed thickeners, inorganic thickeners such as silicic acid and bentonite, organic derivatives such as cellulose derivatives, protein-based, polyacrylate-based, or vinyl-based thickeners can be used. Specifically, a cellulose derivative such as methylcellulose, carboxymethylcellulose, or hydroxyethylcellulose, a protein system such as casein, sodium caseinate, ammonium caseinate, or sodium alginate, a polypolyester such as sodium polyacrylate, or ammonium polyacrylate. Acrylates or vinyls such as polyvinyl alcohol. In addition, an alkali coexisting acrylic resin thickener is supplied as an acrylic resin solution, and the addition of alkali (ammonia) causes the resin to swell and produce a thickening effect. Since it is removed, the effect resulting from the thickener does not remain in the state of being a coating film, which is preferable.
[0062]
As other thickeners, extender pigments such as precipitated calcium carbonate, barium sulfate, alumina, clay, magnesium carbonate, gypsum, kaolin, or aluminum hydroxide, which are called extender pigments, can be used.
[0063]
The above thickeners can be used alone or in combination of two or more.
[0064]
By mixing the components described above, the coating composition for forming a heat insulating layer of the present invention is prepared. The mixing ratio of each component is usually 20 to 240 parts by mass, more preferably 50 to 120 parts by mass, and more preferably 10 to 200 parts by mass, more preferably 100 to 200 parts by mass of the hollow particles with respect to 100 parts by mass of the binder resin. Is blended in an amount of 20 to 100 parts by mass. The solvent is usually blended in an amount of 500 to 5000 parts by weight, more preferably 1000 to 2000 parts by weight, based on 100 parts by weight of the binder resin, and each component is uniformly dissolved or dispersed in the solvent. Moreover, a thickener is 5-50 mass parts normally with respect to 100 weight part of binder resin, More preferably, 5-20 mass parts is mix | blended.
[0065]
In the above blending ratio, if the hollow particles are less than 20 parts by mass, the heat insulating layer obtained by applying the coating composition of the present invention has a low porosity, so sufficient heat insulating performance is often not obtained. On the other hand, when it exceeds 240 parts by mass, the proportion of the binder resin is relatively decreased, and the strength of the heat insulating layer obtained is often lowered.
[0066]
In addition, when the fiber is less than 10 parts by mass, sufficient mechanical strength is often not obtained, and the heat-insulating layer-forming coating composition of the present invention is applied to the breathable sheet and sucked as described later. It is also difficult to form a heat insulating layer by the method. On the other hand, if the fiber exceeds 200 parts by mass, the heat insulation performance is extremely deteriorated, so that the desired heat insulation performance may not be obtained.
[0067]
Also, if the solvent is less than 500 parts by mass, the coating composition has poor fluidity and cannot be applied or impregnated smoothly, and if it exceeds 5000 parts by mass, the viscosity of the coating composition becomes low and the hollow particles are separated. Are often difficult to apply or impregnate.
[0068]
Furthermore, if the thickening agent is less than 5 parts by mass, the thickening effect is insufficient, so that floating or sedimentation of the hollow particles is unavoidable. In addition to the impediment to impregnation, the proportion of the binder resin is relatively low, the strength of the heat insulating layer obtained is reduced, and depending on the type of thickener used, In this case, the thermal conductivity of the portion made of the binder resin and the thickening agent surrounding the hollow particles is increased, so that the heat insulation performance is lowered, which is not preferable.
[0069]
(2) Molded body having a heat insulating layer and a method for producing the same
Although the coating composition for forming a heat-insulating layer of the present invention can be applied to various objects, it is industrially applied on various substrates, or applied or impregnated on impregnated substrates, and dried. It is suitable to be used for the purpose of forming a heat-insulating layer by solidifying by means of, for example. The heat insulating layer may be formed in the form of a coating layer on the substrate, or may be formed in the shape of an impregnated layer that is impregnated into an impregnated substrate. Good. Depending on the type of the heat-insulating layer-forming coating composition or impregnating base material, part of the heat-insulating layer-forming coating composition applied to the impregnating base material is impregnated in the impregnating base material, and the rest is impregnated. It can also be used such that it remains as a coating film on the surface of the conductive substrate.
[0070]
Among the application targets of the coating composition for forming a heat-insulating layer of the present invention, as a substrate on which a coating layer can be formed on a substrate by coating, a film, sheet or plate made of paper, plastic, metal or the like as a material Etc.
[0071]
As used herein, “a substrate that can form a coating layer” may be capable of penetrating liquid components such as solvent and water in the coating composition for forming a heat insulating layer, but is substantially heat insulating. The layer forming coating composition does not permeate, and the solid content in the coating composition remains on the substrate.
[0072]
Among the objects to which the coating composition for forming a heat insulating layer of the present invention is applied, examples of the impregnating base material that can form an impregnated layer inside the base material include natural fibers, synthetic fibers, rock wool, glass fibers, and carbon fibers. Nonwoven fabrics, felts, cloths made from such fibers as the raw materials, paper made from these fibers as raw materials (particularly low-density paper), ceramic sheets, and the like can be used.
[0073]
The term “impregnating substrate” as used herein refers to a material that can penetrate the entire coating composition for forming a heat insulating layer. However, when the impregnation is performed from one side of the base material, the entire thickness is not impregnated so that the heat insulating layer forming coating composition does not reach the opposite surface, and a part of the thickness is impregnated. Include things.
[0074]
As a method for applying the coating composition for forming a heat insulating layer of the present invention to the application target as described above, a known coating method or impregnation method is used.
[0075]
As the coating method, roll coating or bar coating having a wide viscosity range and wide coating amount range is suitable, but other methods may be used.
[0076]
As the impregnation method, a method of immersing the impregnated base material in a tank filled with the coating composition for forming the heat insulating layer (so-called dipping) or a known coating means from one side or both sides of the impregnated base material. Depending on the method of application. After the coating composition for forming a heat-insulating layer has sufficiently penetrated into the base material, the excess impregnating paint remaining on the base material is appropriately scraped or removed, for example, a suction doctor, a doctor roll, or a round bar. The excess is scraped off or removed with a wire bar or the like around which the wire is wound, and the impregnated base material is impregnated with a predetermined amount of the coating composition for forming a heat insulating layer.
[0077]
After applying the coating composition for forming a heat insulating layer to a substrate, the coating layer or the impregnated layer is solidified by drying to obtain a heat insulating layer. Depending on the ingredients of the component blended in the heat insulating layer forming coating composition, especially the binder resin, it is dried at a relatively low temperature and then dried at a relatively high temperature to solidify or is dried at a relatively low temperature. You may solidify by irradiating with an ultraviolet-ray or an electron beam after making it dry or not drying at all.
[0078]
In addition, when heat-fusible fibers are blended in the heat-insulating layer-forming coating composition, the heat-fusible property can be obtained by heat-treating the coating layer or the impregnated layer after drying or the like. The fibers can be fused to the surrounding matrix to give the heat-insulating layer excellent breakage resistance, flexibility, and bending resistance.
[0079]
In order to enhance the heat insulation effect, the coating composition for forming a heat-insulating layer of the present invention desirably has a higher proportion of hollow particles and a relatively smaller proportion of the binder resin. Dissolving and dispersing the coating composition for forming a heat-insulating layer in a small amount in a solvent increases the blending ratio of the solvent, so that the fluidity increases and it becomes difficult to control the pattern or shape of the coating layer, and It takes time to dry. Therefore, productivity when forming the heat insulating layer is deteriorated. Moreover, when the drying time of the coating liquid of the coating composition for heat insulating layer formation is long, since the hollow particles are easily separated in the coating film during drying, the uniformity of the heat insulating layer is deteriorated. When the heat insulating layer in the form of an impregnated layer is formed using the coating liquid of the coating composition for forming a heat insulating layer of the present invention, such a problem does not occur, but the heat insulating property in the form of the coating layer. Such a problem arises when it is desired to form a layer.
[0080]
In order to avoid such a problem, the coating liquid of the coating composition for forming a heat insulating layer of the present invention is applied onto the breathable sheet, and the formed coating layer is sucked from the opposite surface side of the breathable sheet. Then, it is preferable to form a heat insulating layer in the form of a coating layer by removing the solvent and then drying. According to this method, since most of the liquid components can be removed from the coating liquid layer formed on the breathable sheet as the base material in a short time, the coating can be applied even if the blending ratio of the binder resin is small. Pattern collapse of the work layer can be prevented, drying time can be shortened, and further, separation of hollow particles can be prevented. In addition, this method is suitable for producing a single-layered or laminated sheet-like molded body of the heat insulating layer.
[0081]
When the air-permeable sheet used in this method is applied with a coating solution of the heat-insulating layer-forming coating composition on the sheet and subjected to suction treatment from the surface opposite to the surface on which the coating layer is formed, Any solvent may be used as long as the solvent in the coating layer is removed by suction and all or most of the solid content of the coating layer remains on the sheet.
[0082]
After the coating layer of the breathable sheet is solidified by drying or the like to form a heat insulating layer, the breathable sheet is peeled off when the heat insulating layer is peeled off and used as a single-layer molded body, particularly a sheet-shaped molded body. It is desirable that the adhesive strength of the heat insulating sheet is weak. Therefore, the liquid component contained in the coating liquid layer can be easily passed by suction from the above-mentioned “base material capable of forming the coating layer”, but is contained in the coating liquid layer. If a material in which substantially all the solid content remains on the substrate is used, there is little entanglement between the fibers of the breathable sheet and the heat-insulating layer, so that the adhesive force is small and easy to peel off.
[0083]
On the other hand, if you want to use the laminate of the breathable sheet and the heat-insulating layer as it is as the heat-insulated molded product, especially as a sheet-shaped molded product, the one with the greater adhesive force between the breathable sheet and the heat-insulating sheet as the base Is desirable. Therefore, from the above-mentioned “impregnating base material”, the liquid component in the coating liquid can be easily passed by suction, and only a part of the solid component contained in the coating liquid layer is impregnated. However, when most of the material that remains in the form of a coating layer on the base material is used, a part of the heat insulating layer enters the inner space of the air permeable sheet from the surface of the air permeable sheet, and the air permeable sheet. The entanglement between the fibers and the heat insulating layer increases, making it difficult to peel off.
[0084]
Specifically, as the breathable sheet from which the heat-insulating layer is difficult to peel, it is preferable to select and use a non-woven fabric or synthetic paper having an appropriate breathability that is not clogged. The nonwoven fabric is manufactured by various methods such as a spunbond method, a card method, an airlay method, and a wet method, and any method manufactured by any method can be used.
[0085]
In particular, a nonwoven fabric composed of fibers having a thickness of 0.5 to 7 denier and a length of 10 to 60 mm can easily suck the liquid component of the coating liquid of the coating composition for forming a heat insulating layer, and the solid component is moderate. The fibers of the nonwoven fabric and the heat insulating layer are sufficiently entangled with each other, but most of the solid component remains on the nonwoven fabric, so that the coating layer can be formed thick. Furthermore, a nonwoven fabric made of fibers having a thickness of 0.5 to 7 denier and a length of 10 to 60 mm has sufficient strength, and imparts heat insulation to a sheet-like molded body formed by laminating a heat insulating layer on the nonwoven fabric. When applying to a desired site, it is easy to match the shape of the applied site.
[0086]
If the heat-insulating layer is formed by applying the heat-insulating layer-forming coating composition of the present invention on a non-woven fabric containing heat-fusible fibers and then performing heat treatment such as hot press, The adhesive fibers are fused to the heat insulating layer, and the adhesive strength between the nonwoven fabric and the heat insulating layer is increased. The heat-fusible fiber is made of the same material as the heat-fusible fiber that can be blended in the heat-insulating layer-forming coating composition of the present invention, that is, a single fiber or core of various thermoplastic resins or thermosetting resins. Composite fibers such as a sheath structure, a combined structure, and a sea-island structure can be used. Among them, a composite fiber having a core-sheath structure in which the sheath part is formed of polyethylene or polyethylene terephthalate and the core part is formed of polyethylene terephthalate is preferable, and both the sheath part and the core part are formed of polyethylene terephthalate (PET). Is particularly preferred.
[0087]
A non-woven fabric made of hollow fibers having a cavity in the axial direction may be used as the breathable sheet. When a nonwoven fabric made of hollow fibers is used as the base material of the heat insulating layer, the heat insulating effect of the nonwoven fabric is added to the heat insulating property of the heat insulating layer, so that the heat insulating property of the molded body is improved.
[0088]
After applying the coating liquid of the heat-insulating layer-forming coating composition to any of the breathable sheets as described above to form a coating layer, the liquid component is removed from the coating layer, and further drying, etc. To form a heat insulating layer. Depending on the type of the binder resin, the coating layer may be solidified by irradiation with ultraviolet rays or the like after drying the coating layer or without performing a drying treatment.
[0089]
In addition, when heat-fusible fibers are blended in the heat-insulating layer-forming coating composition, when the coating layer is dried and then hot-pressed, the heat-fusible fibers are thermally fused to the surrounding matrix. Thus, a three-dimensional network structure can be formed and the thickness of the molded body can be adjusted.
[0090]
In this way, a molded body in which a breathable sheet is laminated on one side of the heat insulating layer is obtained. This molded body can be applied to a place where heat insulation is desired as it is by means such as sticking. Moreover, a breathable sheet can be peeled from this molded body to obtain a single layer sheet of a heat insulating layer.
[0091]
Furthermore, when the surface strength of the heat insulating layer is insufficient, a base sheet may be laminated on both surfaces of the heat insulating layer. For example, the coating liquid of the heat-insulating layer-forming coating composition is applied onto the nonwoven fabric as the first breathable sheet to form a coating liquid layer, and from the opposite side of the first breathable sheet The liquid component of the coating layer is removed by suction, and a non-woven fabric is layered as a second breathable sheet on the exposed surface side of the coating layer after suction before or after the coating layer is dried. The molded body in which the nonwoven fabric is bonded to both surfaces of the heat insulating layer is obtained by hot pressing the laminate after drying the layer. As another method, the coating liquid of the heat-insulating layer-forming coating composition is applied onto the nonwoven fabric that is the first air-permeable sheet to form a coating liquid layer, and the coating liquid layer A non-woven fabric is layered as a second breathable sheet on top, sucked from both sides, solidified by drying, etc., and hot-pressed as necessary. can get.
[0092]
【Example】
In the following, the present invention is described in more detail through examples.
[0093]
Example 1
(1) Preparation of coating composition
First, while stirring 93 parts by weight of water, 2.3 parts by weight of polyacrylonitrile hollow particles (manufactured by Matsumoto Yushi Seiyaku Co., Ltd., product number F-80E) as a solid content, acrylic resin as a binder resin (manufactured by Chuo Rika Kogyo Co., Ltd., product number ET) -84) as a solid content, 3.8 parts by weight, an alkali resin thickener (manufactured by Chuo Rika Kogyo, product number FK-610) as a solid content, 0.7 parts by weight, and 25% aqueous ammonia 0.8 weight Parts were added in this order to prepare an intermediate preparation. In addition, the said mixture ratio is solid content basis except water.
[0094]
This intermediate preparation liquid (solid content: 7% by weight) further has a PET-PET core-sheath structure, a fiber having a thickness of 1.5 denier and a length of 5 mm with respect to the solid content of 4.5 g. 1.35 g was added and stirred and mixed with a mixer, and water was further added to obtain a water-based coating composition for forming a heat insulating layer having a solid concentration of 1% by weight.
[0095]
(2) Production of a molded body having a heat insulating layer
On the mesh sheet, basis weight 20g / m ² And the nonwoven fabric containing the binder fiber of the PET-PET core-sheath structure is fixed, and the coating composition for forming the heat insulating layer is applied to the surface of the nonwoven fabric (the coating amount is 93.6 g / m). ² ) After coating and coating the same non-woven fabric on the coating layer, the liquid component was removed by suction from the lower side of the obtained laminate. After suction, the laminate was press-molded and dried at 110 ° C. with a drum dryer. After drying, the laminate was heat-pressed at 150 ° C. for 10 seconds. In this way, a three-layer molded body in which the nonwoven fabric was laminated on both sides of the heat insulating layer was obtained.
[0096]
(Example 2)
A nonwoven fabric similar to that used in Example 1 was fixed on the mesh sheet, and the same amount of the coating composition for forming a heat insulating layer as that used in Example 1 was applied to the surface of the nonwoven fabric. Thereafter, the liquid component was removed by suction from the nonwoven paper side of the obtained laminate having a two-layer structure. After suction, the laminate was press-molded and dried at 110 ° C. with a drum dryer. After drying, the laminate was heat-pressed at 150 ° C. for 10 seconds. In this way, a two-layered molded body in which a nonwoven fabric was laminated on one side of the heat insulating layer was obtained. Thereafter, the non-woven paper was peeled off from the molded body to obtain a single-layer molded body consisting only of a heat insulating layer.
[0097]
(Example 3)
The following test was also conducted on the two-layered molded body before peeling the nonwoven paper in Example 2.
[0098]
Example 4
A nonwoven fabric similar to that used in Example 1 was fixed on the mesh sheet, and the same amount of the coating composition for forming a heat insulating layer as that used in Example 1 was applied to the surface of the nonwoven fabric. Thereafter, the liquid component was removed by suction from the nonwoven paper side of the obtained laminate having a two-layer structure. After suction, the laminate was press-molded and dried at 110 ° C. with a drum dryer. After drying, the laminate was heat-pressed at 150 ° C. for 20 seconds. In this way, a two-layered molded body in which a nonwoven fabric was laminated on one side of the heat insulating layer was obtained.
[0099]
(Example 5)
Double coating amount of coating composition for forming heat-insulating layer by 187.2 g / m ² Except for changing to, a molded article having a three-layer structure was obtained in the same manner as in Example 1, in which nonwoven fabrics were laminated on both sides of the heat insulating layer.
[0100]
(Example 6)
Double coating amount of coating composition for forming heat-insulating layer by 187.2 g / m ² A single-layer molded body consisting only of a heat-insulating layer was obtained in the same manner as in Example 2 except that it was changed.
[0101]
(Example 7)
A non-woven fabric similar to that used in Example 1 is fixed on the net-like sheet, and the coating composition for forming an insulating layer similar to that used in Example 1 is doubled in amount to 187. 2g / m ² After coating, the liquid component was removed by suction from the nonwoven paper side of the resulting laminate having a two-layer structure. After suction, the laminate was press-molded and dried at 110 ° C. with a drum dryer. After drying, the laminate was heat-pressed at 150 ° C. for 20 seconds. In this way, a two-layered molded body in which a nonwoven fabric was laminated on one side of the heat insulating layer was obtained. Thereafter, the non-woven paper was peeled off from the molded body to obtain a single-layer molded body consisting only of a heat insulating layer.
[0102]
(Comparative Example 1)
About the heat insulation sheet which sliced hard polyurethane (the product made from Toyo Rubber Industries, product number Soflan R board (W30)), the following test was done with the molded object obtained in said each Example.
[0103]
(Test items)
The following tests were conducted. The results are shown in the table below.
[0104]
(1) Average thickness of molded body (mm)
The average thickness of the entire molded body was measured. That is, when the nonwoven fabric was laminated, the average thickness including the thickness of the nonwoven fabric was measured.
[0105]
(2) Density (g / cm ^Three )
The density of the molded body including the nonwoven fabric was measured.
[0106]
(3) Thermal insulation performance (temperature difference ° C)
[0107]
First, as shown in FIG. 1, a foamed polystyrene frame (2) is attached around an aluminum plate (1) having a thickness of 1.0 mm, and the molded body obtained in the example or the comparative example is 20 mm on the aluminum plate. A sample (3) cut to × 20 mm was placed. Then, the aluminum plate was floated on ice water (4) and left in an environment of 23 ° C. and 50 Rh for 35 minutes. After standing, the temperature of the upper surface (5) of the aluminum plate and the temperature of the center portion (6) of the upper surface of the molded body sample were measured, and it was evaluated that the greater the temperature difference, the better the heat insulation performance.
[0108]
Moreover, when the thermal conductivity was measured about the sample of Examples 1 thru | or 7, all were the range of 0.03-0.2 W / m * K.
[0109]
(4) Flexibility
A bending test specified in JIS K7203 was performed, and the case where the bending portion had a curvature radius of 5.0 mm and a load of 1.0 N was not damaged was evaluated as pass (◯), and the case where it was damaged was evaluated as unacceptable (x).
[0110]
[Table 1]

[0111]
【The invention's effect】
Since the coating composition for forming a heat insulating layer of the present invention contains hollow particles having closed cavities, when the heat insulating layer is formed using this coating composition, a large amount of closed cells are formed in the heat insulating layer. Can be formed, high heat insulation can be obtained, and the size and amount of closed cells can be easily adjusted, so that the heat insulation performance can be easily controlled.
[0112]
Further, the coating composition for forming a heat insulating layer of the present invention contains fibers, preferably fibers having a thickness of 0.3 to 5 denier and a length of 1 to 7 mm. When a heat insulating layer is formed by using it, excellent heat resistance and surface strength can be imparted to the heat insulating layer. When heat-fusible fibers are blended as fibers in the heat-insulating layer forming coating composition and the coating layer or impregnated layer of the coating composition is heat-treated, the heat-fusible fibers are heat-fused into the matrix of the heat-insulating layer. Since it is attached to form a three-dimensional network structure, the rupture resistance and surface strength of the heat insulating layer are particularly improved.
[0113]
By using the coating composition for forming a heat insulating layer of the present invention, a heat insulating layer can be formed in various places where heat insulating properties are desired. For example, decorative paper for interior or exterior of wallpaper, home appliances, etc. It is used as a heat insulating material.
[0114]
In particular, since the coating composition for forming a heat insulating layer of the present invention has the above-described properties, it is possible to form a single-layer or laminated sheet-like molded body having a heat insulating layer. This sheet-shaped molded article is excellent in heat insulation even if it is thin, and is excellent in flexibility and bending resistance, and can be used as a heat insulation sheet that can be easily matched to the shape of the place where heat insulation is desired. It can be suitably used as heat-insulating decorative paper that covers a member having fine irregularities on its surface, such as decorative paper for frames.
[0115]
According to the present invention, the thermal conductivity is 0.01 to 0.5 W / m · K, and in the bending test specified in JISK7203, a load of 1.0 N is applied with a curvature radius of 5.0 mm at the bent portion. It is possible to form a thin heat-insulating layer excellent in heat insulating properties and flexibility so as not to break.
[0116]
A metal window frame such as an aluminum sash is formed by using a fiber having a moisture absorption of less than 10% at a temperature of 20 ° C. and a relative humidity of 95% for the heat insulating layer of the present invention. Even when it is applied to a place where condensation occurs, the heat insulating property is hardly lowered due to moisture absorption of the heat insulating layer.
[0117]
The coating liquid of the coating composition for forming a heat insulating layer of the present invention is applied to one side of the breathable sheet, and the liquid component is removed by sucking the coating liquid layer from the opposite side of the breathable sheet. By solidifying the coating layer of the solid content remaining on the sheet, a sheet-like molded body in which a breathable sheet is laminated on the heat insulating layer is obtained.
[0118]
According to this method, most of the liquid components can be removed from the coating liquid layer formed on the breathable sheet as the base material within a short period of time. Pattern collapse of the work layer can be prevented, drying time can be shortened, and further, separation of hollow particles in the coating layer can be prevented.
[0119]
The laminate of the heat insulating layer and the breathable sheet obtained by this method may be used as a heat insulating material as it is, or the breathable sheet can be peeled from this laminate to obtain a single heat insulating layer. .
[0120]
When used as a heat insulating material in the form of a laminate of a heat insulating layer and a breathable sheet, the nonwoven fabric is preferably a non-woven paper, preferably a fiber having a thickness of 0.5 to 7 denier and a length of 10 to 60 mm. When the heat insulating layer is formed by the above method, a part of the heat insulating layer enters the internal voids of the nonwoven fabric and becomes entangled, making it difficult to peel off. A thick coating layer can be formed. In addition, the nonwoven fabric has sufficient strength and excellent bending resistance.
[0121]
Moreover, in order to improve the heat insulation effect of the molded product having a heat insulating layer, hollow fibers are used as the fibers of the coating composition for forming a heat insulating layer of the present invention, or the hollow fibers are laminated as the nonwoven fabric laminated on the heat insulating layer. It is preferable to use a non-woven fabric.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining the outline of a test apparatus for evaluating the heat insulating performance of a sheet-like heat insulating molded body.
[Explanation of symbols]
1 ... Aluminum plate
2 ... Styrofoam frame
3 ... Molded sample
4 ... ice water
5. Top surface of aluminum plate
6 ... Center part of the upper surface of the compact

Claims

As essential components, a binder resin, the hollow particles having a closed cavity, and, Ri Na blended with fibers,
A coating composition for forming a heat insulating layer , wherein the fiber is a heat-fusible fiber .

The coating composition for forming a heat insulating layer according to claim 1, wherein at least a part of the surface of the heat-fusible fiber is formed of a thermoplastic resin .

The heat-fusible fiber is a composite having a core-sheath structure in which a core part is formed with a resin having a relatively high melting temperature or softening temperature and a sheath part is formed with a resin having a relatively low melting temperature or softening temperature. The coating composition for forming a heat insulating layer according to claim 2 , wherein the coating composition is a fiber .

4. The coating composition for forming a heat insulating layer according to claim 3, wherein the core portion is made of polyethylene terephthalate and the sheath portion is made of polyethylene or polyethylene terephthalate .

3. The composite fiber according to claim 2, wherein the heat-fusible fiber is a composite fiber having a combined structure composed of two or more portions respectively formed of thermoplastic resins having different melting temperatures or softening temperatures . A coating composition for forming a heat insulating layer.

As essential components, a binder resin, the hollow particles having a closed cavity, and, Ri Na blended with fibers,
The said fiber is a hollow fiber which has a cavity in an axial direction, The coating composition for heat insulation layer formation characterized by the above-mentioned.

It has hollow particles having closed cavities as essential components, and a heat insulating layer formed by blending fibers into a binder resin and solidifying them ,
Wherein the fiber is a heat-fusible fibers, wherein the three-dimensional network in the heat-insulating layer by thermal fusion of the fibers are formed, the molded body.

The molded body according to claim 7, wherein at least a part of the surface of the heat-fusible fiber is formed of a thermoplastic resin.

It has hollow particles having closed cavities as essential components, and a heat insulating layer formed by blending fibers into a binder resin and solidifying them,
The molded article, wherein the fiber is a hollow fiber having a cavity in the axial direction.

It has hollow particles having closed cavities as essential components, and a heat insulating layer formed by blending fibers into a binder resin and solidifying them,
A molded article, wherein the fiber has a moisture absorption of less than 10% at a temperature of 20 ° C and a relative humidity of 95%.

A hollow particle having a closed cavity as an essential component, and a sheet-like molded body provided with a heat insulating layer formed by mixing and solidifying a fiber with a binder resin ,
A molded body, which is a sheet-like laminate formed by laminating a breathable sheet on at least one surface side of the heat insulating layer.

The molded body according to claim 11, wherein a breathable sheet is laminated on both surfaces of the heat insulating layer.

The molded body according to claim 11, wherein a part of the heat insulating layer enters an internal space of the air permeable sheet from the surface of the air permeable sheet.

The molded article according to claim 11, wherein the breathable sheet is a nonwoven fabric.

The molded body according to claim 14, wherein the nonwoven fabric is made of fibers having a thickness of 0.5 to 7 denier and a length of 10 to 60 mm.

The said nonwoven fabric contains the heat-fusible fiber, The molded object of Claim 14 characterized by the above-mentioned.

The said nonwoven fabric consists of hollow fiber which has a cavity in an axial direction, The molded object of Claim 14 characterized by the above-mentioned.

As an essential component, a binder resin, hollow particles having closed cavities, and a coating solution for forming a heat insulating layer formed by blending fibers in a solvent are applied on a breathable sheet, and a formed coating layer is formed. A method for producing a molded body, in which a solvent is removed by suction from the opposite side of the breathable sheet, and then a heat insulating layer is formed by solidification,
A heat-fusible fiber is used as the fiber, and the heat-fusible fiber is thermally fused to the matrix of the coating layer by heating the coating layer after drying. The manufacturing method of a molded object.

As an essential component, a binder resin, hollow particles having closed cavities, and a coating solution for forming a heat insulating layer formed by blending fibers in a solvent are applied on a breathable sheet, and a formed coating layer is formed. A method for producing a molded body, in which a solvent is removed by suction from the opposite side of the breathable sheet, and then a heat insulating layer is formed by solidification,
On the exposed surface side of the coating layer, a second breathable sheet is layered before or after the coating layer is dried, and the coating layer is dried and then hot-pressed. Production method.

As an essential component, a binder resin, hollow particles having closed cavities, and a coating solution for forming a heat insulating layer formed by blending fibers in a solvent are applied on a breathable sheet, and a formed coating layer is formed. A method for producing a molded body, in which a solvent is removed by suction from the opposite side of the breathable sheet, and then a heat insulating layer is formed by solidification,
A non-woven fabric is used as the air permeable sheet.

21. The method for producing a molded body according to claim 20, wherein a nonwoven fabric made of fibers having a thickness of 0.5 to 7 denier and a length of 10 to 60 mm is used as the nonwoven fabric.

The method for producing a molded body according to claim 20, wherein the nonwoven fabric contains heat-fusible fibers.

As an essential component, a binder resin, hollow particles having closed cavities, and a coating solution for forming a heat insulating layer formed by blending fibers in a solvent are applied on a breathable sheet, and a formed coating layer is formed. A method for producing a molded body, in which a solvent is removed by suction from the opposite side of the breathable sheet, and then a heat insulating layer is formed by solidification,
After forming the heat insulating layer, the air-permeable sheet is removed from the heat insulating layer to obtain a single layer formed body made of only the heat insulating layer.

The method for producing a molded body according to any one of claims 18 to 23, wherein a sheet-shaped molded body is formed.