JP4428815B2 - Polyester resin laminated polystyrene resin foam - Google Patents

Description

前記一般式（１）において、Ｒは水素原子またはメチル基を示し、Ｚはハロゲン原子またはメチル基を示し、ｐは０または１〜３の整数である。
前記ポリスチレン系樹脂としては、ポリスチレン、ゴム変性ポリスチレン、スチレン−アクリロニトリル共重合体、スチレン−ブタジエン−アクリロニトリル共重合体、スチレン−アクリル酸共重合体、スチレン−メタクリル酸共重合体、スチレン−メタクリル酸メチル共重合体、スチレン−メタクリル酸エチル共重合体、スチレン−アクリル酸メチル共重合体、スチレン−アクリル酸エチル共重合体、スチレン−無水マレイン酸共重合体、ポリスチレン−ポリフェニレンエーテル共重合体、ポリスチレンとポリフェニレンエーテルとの混合物などが例示される。これらの樹脂に脆性改善等を目的としてスチレン−共役ジエンブロック共重合体やその水添物をブレンドしたものも使用することができる。尚、ビカット軟化点が１１０℃以上のポリスチレン系樹脂を使用することにより、本発明の発泡体の耐熱性を向上させることができるためその使用は好ましい。本明細書において、樹脂のビカット軟化点はＪＩＳ Ｋ７２０６（試験荷重はＡ法、液体加熱法で昇温速度は５０℃／時の条件）にて求められる値を指す。
【００１５】
上記のポリスチレン系樹脂の１９０℃剪断速度１００ｓｅｃ^-1における溶融粘度は２００Ｐａ・Ｓ以上、１００００Ｐａ・Ｓ未満であることが望ましい。溶融粘度が２００Ｐａ・Ｓ未満では発泡体成形時にダイスより押出された溶融樹脂が垂れてしまい成形が困難になる。一方、１００００Ｐａ・Ｓ以上では粘度が高すぎて押出圧力が上昇し押出発泡成形が困難で良好な発泡体に成形することが難しくなる。尚、本明細書において、剪断速度１００ｓｅｃ^-1の条件下での樹脂の溶融粘度は、オリフィス径が１．０ｍｍ、オリフィス長さが１０ｍｍのオリフィスを用い樹脂温度１９０℃の条件にてチアスト社製レオビス２１００で求められる値である。
【００１６】
本発明の発泡体の基材樹脂は、前記ポリスチレン系樹脂を主成分とするものであり、他の成分としてパラフィン、ポリカプロラクトン等の流動性改質剤、タルクや重曹、クエン酸等の造核剤、酸化防止剤、熱安定剤、帯電防止剤、導電性付与剤、紫外線防止剤、着色剤、難燃剤、無機充填剤、ゴム、エラストマー等の各種の添加剤を目的に応じて適量添加することができる。
また、本発明の目的、効果を阻害しない範囲でポリエチレン系樹脂、ポリプロピレン系樹脂、アクリル系樹脂等の熱可塑性樹脂をおおむね４５重量％以下の割合で基材樹脂に含有させることができる。その量は、特に、基材樹脂中に２０重量％以下、好ましくは１０重量％以下であることが好ましい。その量が多すぎる場合は発泡体のガス抜けが早くなり押出発泡後に発泡体が収縮してしまったり、発泡体の熱成形時に気泡が溶融破泡してしまう虞がある。
基材樹脂に含有させる流動性改質剤の量は、特に、基材樹脂中に２〜３０重量％、好ましくは５〜２０重量％であることが好ましい。
【００１７】
本発明におけるポリスチレン系樹脂発泡体は、好ましくは上記基材樹脂を高温高圧条件下で溶融し、その溶融物を発泡剤と混合し、低圧帯域に押出発泡させることにより得られる。
前記基材樹脂は、ポリスチレン系樹脂とを主成分とするものであるが、他の熱可塑性樹脂等を混合する場合は、特定の重量比となるようにあらかじめポリスチレン系樹脂と他の熱可塑性樹脂とをドライブレンド、ニーダーによる混練等を行なった後、押出機に供給して押出発泡を行なっても、スクリューフィーダー等により特定の重量比となるように各々の樹脂等を押出機に供給し押出機中にて混練して押出発泡を行なっても本発明のポリスチレン系樹脂発泡体を得ることができる。
【００１８】
前記発泡剤としては、不活性ガス、飽和脂肪族炭化水素、飽和脂環族炭化水素、芳香族炭化水素、ハロゲン化炭化水素、エーテル、ケトン等が挙げられ、これらの単独又は２種類以上の組み合わせたものが使用される。
発泡剤を具体的に例示すると、炭酸ガス、窒素、水、プロパン、ノルマルブタン、イソブタン、ノルマルペンタン、イソペンタン、ネオペンタン、ノルマルヘキサン、２−メチルペンタン、３−メチルペンタン、２，２−ジメチルブタン、２，３−ジメチルブタン、メチルシクロプロパン、シクロブタン、シクロペンタン、１，１−ジメチルシクロプロパン、メチルシクロペンタン、エチルシクロペンタン、１，１，２−トリメチルシクロプロパン、トリクロロフロロメタン、ジクロロジフロロメタン、１，１−ジクロロ−１，１，１，２−テトラフルオロエタン、１，１−ジフルオロ−１−クロロエタン、１，１，１，２−テトラフルオロエタン、１，１−ジフルオロエタン、１，１，１，２，２−ペンタフルオロエタン、メチルクロライド、エチルクロライド、メチレンクロライド、エチレンクロライド、ジメチルエーテル、２−エトキシエタノール、アセトン、エチルメチルケトン、アセチルアセトン等で、これらの単独又は２種類以上の組み合わせたものが挙げられる。
更に、分解型発泡剤としては、アゾジカルボンアミド、ジニトロソペンタメチレンテトラミン、アゾビスイソブチロニトリル、重炭酸ナトリウム等が挙げられる。これらの分解型発泡剤は単独又は適宜混合して用いることができる。
発泡剤の使用量は、目的の発泡体の密度に応じて適宜使用されるが、おおむね基材樹脂１００ｇあたり０．０１〜０．１モルの範囲で選択することができる。
【００１９】
前記基材樹脂を溶融し、その溶融物を発泡剤と混合して低圧帯域に押出発泡させ発泡体を得るにあたり、溶融混合と冷却をそれぞれ一台以上の押出機にて行なうことが望ましい。
すなわち、一般に押出発泡は樹脂を溶融し発泡剤を加えた後、樹脂が発泡に適した粘度に達するまで冷却することによって行なわれる。このため、樹脂と発泡剤との混練工程においては、押出機の混練機能を有するスクリューを高回転数で回転させ十分に混練することが望まれる。一方、冷却工程においては冷却効率を高めるために、可能な限りせん断発熱を抑制するためにスクリューの回転数を低くすることが望まれる。従って、溶融混合と冷却とを一台の押出機で行なうと十分な冷却を行なうためにはスクリューの回転数を低くしなければならず、混合樹脂の混練や樹脂と発泡剤との混練が不十分となり易く樹脂の発泡状態が悪化したり、押出機の吐出量が低下し、生産性が低下するといった不具合を生じることがある。本発明の熱可塑性樹脂発泡体を製造するために使用する押出機の種類及びスクリュー形状等は特に限定されるものではない。なお、前記押出機の構造として押出機とダイスとの間にスタティックミキサー、ギアポンプを取付けたものが、厚み、外観、密度等において良好な発泡体を得る上で好ましい。
【００２０】
前記方法によって得られるＰｅ／ＰＳ発泡体における発泡シートまたは発泡板の密度は好ましくは０．０５〜０．７ｇ／ｃｍ³更に好ましくは０．１〜０．５ｇ／ｃｍ³である。密度０．０５ｇ／ｃｍ³未満では成形体の強度が不足することがあるばかリでなく、加熱真空成形するときに伸びが不足で成形体に穴が開くことがある。一方、０．７ｇ／ｃｍ³を越えると軽量性、経済的にも問題があるが容器の断熱性が低下し容器に食品を入れて加熱すると、熱くて手で持てず発泡体としての特徴である断熱性が不十分なことがある。
また、更に、Ｐｅ／ＰＳ発泡体を構成している発泡体のみの厚みは好ましくは０．５〜７ｍｍ、更に好ましくは１〜５ｍｍである。厚み０．５ｍｍ未満では強度や断熱性の点で実用に耐えない虞がある。７ｍｍを越えるものは、加熱成形の際に発泡体内部と外部の加熱ムラが起こりやすく、精密な温度制御が必要となる。特に熱成形用のものは０．７〜５ｍｍのものが好ましい。
また、本発明のＰｅ／ＰＳ発泡体の坪量が２５０〜６００ｇ／ｍ²、フィルム状の芳香族ポリエステル系樹脂の厚みが０．０１〜０．２ｍｍであることがより好ましい。坪量が２５０ｇ／ｍ²未満では特に大きな絞り比（０．８以上）の成形品を得ようとすると成形品側面が薄くなり強度不足となりやすい。一方、坪量が６００ｇ／ｍ²を超えると一般容器としては重すぎてコストアップである。
【００２１】
本発明のＰｅ／ＰＳ発泡体を構成している発泡体の連続気泡率は５０％以下、好ましくは３０％以下である。連続気泡率５０％を超える場合では、熱成形等の際に発泡体の二次発泡性が低下するために発泡体の金型再現性悪化、成形体の厚み厚薄の発生等の熱成形性の低下が見られる。また、得られる成形体の強度も同じ密度では弱くなる。
尚、発泡体の連続気泡率は、Ｐｅ／ＰＳ発泡体のフィルム状の芳香族ポリエステル系樹脂等の積層されたフィルム状の樹脂を除いた発泡体の連続気泡率であり、ＡＳＴＭ Ｄ２８５６、手順Ｃによって発泡体の実容積（独立気泡部分の容積と樹脂部分の容積との和）Ｖｘ（ｃｍ³)を求め、次式により算出した値である。
【数１】

但し、Ｖａ：試験片の外形寸法から求められる発泡体の見掛けの容積（ｃｍ³)
Ｗ ：試験片における発泡体の重量（ｇ)
ρ ：試験片における発泡体の基材樹脂の密度（ｇ／ｃｍ³)
また、発泡体の重量は、後述する発泡体の密度と発泡体の見掛けの容積から算出する値を採用する。
【００２２】
本明細書において、発泡体の密度の測定は下記に示す方法で行う。予め前記したＰｅ／ＰＳ発泡体の厚みと坪量を測定し、顕微鏡によりＰｅ／ＰＳ発泡体の押出方向に対し、垂直な幅方向のＰｅ／ＰＳ発泡体の断面を等間隔で１０点撮影し、撮影した写真より測定された樹脂層の厚みと接着層の厚みの平均値を算出する。前記各層の厚みをＰｅ／ＰＳ発泡体の厚みから引いた値を発泡体の厚みとした。次いで樹脂層の厚みと接着層の厚みに各層を構成している樹脂密度をかけ単位換算して樹脂層及び接着層の坪量を算出する。前記の樹脂層と接着層の坪量をＰｅ／ＰＳ発泡体の坪量から引いた値を発泡体の坪量とする。この発泡体の坪量を前記した発泡体の厚みで割った値を単位換算し発泡体の密度として採用する。
【００２３】
本発明のＰｅ／ＰＳ発泡体においては、フィルム状の芳香族ポリエステル系樹脂をポリスチレン系樹脂発泡体の片面に接着層を介して積層し、その他方の片面にフィルム状のポリスチレン系樹脂を積層することができる。このポリスチレン系樹脂を積層することによって多層発泡体の熱成形性を向上できる他、その面への印刷性が向上する。積層されるポリスチレン系樹脂は特に限定されるものではないが、耐衝撃性の強いハイインパクトポリスチレン等のゴム変性ポリスチレン、スチレン−ブタジエン−スチレンブロック共重合体、スチレン−イソプレン−スチレンブロック共重合体等のスチレン−共役ジエンブロック共重合体が好適である。また必要に応じてこれらをポリスチレン樹脂に混合したものや、ポリスチレン樹脂に適宜ゴム、エラストマーを加えてたものも好適である。フィルム状のポリスチレン系樹脂の厚みは０．０５〜０．５ｍｍが好ましく、特に０．０８〜０．２ｍｍ、さらには０．０８〜０．２ｍｍでかつもう一方に積層されているフィルム状のポリエステル系樹脂の厚みの６倍以下１倍以上が好ましい。該厚みが０．０５ｍｍ未満では十分な成形性の向上効果が得られ難く、該厚みが０．５ｍｍを越える場合はコスト高となってしまうし、ポリエステル系樹脂層の６倍を超えると熱成形時にポリエステル系樹脂層面とポリスチレン系樹脂層面との加熱バランス制御の精度を高める必要が生じることがある。また、フィルム状のポリスチレン系樹脂の密度は多少発泡させたり、無機物質を添加した場合を考慮して０．３ｇ／ｃｍ³以上であることが好ましい。密度が０．３ｇ／ｃｍ³未満の場合はこの面への印刷性が低下するおそれがある。
【００２４】
次にフィルム状芳香族ポリエステル系樹脂とポリスチレン系樹脂からなる発泡体とを接着する接着層（以下、単に接着層（１）ともいう。）について記述する。接着層（１）としては、ポリエチレン系重合体、ポリプロピレン系重合体、エチレン−酢酸ビニル共重合体等のポリオレフィン系重合体、前述の芳香族ポリエステル系樹脂を構成する重合体中のジカルボン酸成分単位及び重合体中のジオール成分単位からなる芳香族又は脂肪族のポリエステル系重合体、その他、芳香族ポリエステル系樹脂とポリスチレン系樹脂との混合物、ポリオレフィン系重合体とポリスチレン系樹脂との混合物、前記ポリエステル系重合体と同様のジカルボン酸成分単位及びジオール成分単位からなるポリエステル系重合体とポリスチレン系樹脂との混合物等を主成分とし、更にそれらに必要に応じて相溶化成分や弾性成分として作用する添加剤を添加しポリスチレン系樹脂からなる発泡体と芳香族ポリエステル系樹脂との接着強度が４９０ｍＮ／ｃｍ以上の接着性が発現されるものが挙げられる。尚、前記接着層（１）の主成分とは、接着に寄与する樹脂の成分のことを意味し、接着層全重量に対し２５重量％以上、好ましくは３０重量％以上含まれているということである。また、前記相溶化成分や弾性成分として作用する添加剤としては、リサイクル性、コスト面で、ハイインパクトポリスチレン等のゴム変性ポリスチレン、スチレン−ブタジエン−スチレンブロック共重合体、スチレン−イソプレン−スチレンブロック共重合体等のスチレン−共役ジエンブロック共重合体や、その水添物等のスチレン系のものを採用することが好ましい。
【００２５】
発泡体と芳香族ポリエステル系樹脂との間の接着強度は前記の通り４９０ｍＮ／ｃｍ以上、より好ましくは９６０ｍＮ／ｃｍ以上、更に好ましくは２９４０ｍＮ／ｃｍ以上が望ましい。接着強度が４９０ｍＮ／ｃｍ未満では絞り比の大きい（０．４以上）成形品を得ようとした場合、成形時に変性ポリエステル系樹脂層や接着層の剥離が生じる可能性が高い。
尚、本明細において接着強度が４９０ｍＮ／ｃｍ以上とは、当然、発泡体と芳香族ポリエステル系樹脂とが剥離しないものも含まれる。
本発明において、発泡体と芳香族ポリエステル系樹脂との間の接着強度は、幅２５ｍｍの試験片を切り出し、ＪＩＳ Ｚ ０２３７に準拠し、剥離速度３００ｍｍ／ｍｉｎの９０°剥離試験にて測定して求めた剥離強度（ｍＮ／２５ｍｍ）を、２．５で割り算して算出される値を接着強度（ｍＮ／ｃｍ）とする。
【００２６】
接着層（１）の主成分において十分な接着性の面からは、ポリオレフィン系重合体、またはポリオレフィン系重合体とポリスチレン系樹脂との混合物、融点が２００℃以下であるポリエステル系樹脂とポリスチレン系樹脂との混合物、ポリエステル系重合体、またはポリエステル系重合体とポリスチレン系樹脂との混合物を主成分とするものが好ましく、中でもポリオレフィン系重合体のうち融点が１０５℃以上更には１１０℃以上のエチレン−酢酸ビニル共重合体、又は該エチレン−酢酸ビニル共重合体とハイインパクトポリスチレン等のポリスチレン系樹脂との混合物がコスト、接着性、耐熱性の面で特に好ましい。ポリオレフィン系重合体またはポリエステル系重合体に、ポリスチレン系樹脂を混合して用いる場合には、接着強度４９０ｍＮ／ｃｍ以上を満たす範囲で任意の混合比を選択することができ、コストの面からポリスチレン系樹脂を５０重量％以上配合することが望ましい。また、エチレン−酢酸ビニル共重合体、ポリエステル系重合体のうち、非結晶性又は、融点が２００℃以下１０５℃以上の融点を持つものを選択することが耐熱性の高いＰｅ／ＰＳ発泡体が得られる点で望ましい。
本明細書における融点は、ＪＩＳ Ｋ７１２１に準じて行なう熱流束示差走査熱量測定によって得られるＤＳＣ曲線の融解ピークから求められる。詳細は以下の通りである。厚み０．５ｍｍ以下のフイルム約５ｍｇを試験片とし、該試験片を示差走査熱量測定装置の容器へ詰め常温から加熱速度１０℃／分で融解ピーク終了時の温度よりも約３０℃高い温度まで昇温した後、直ちに冷却速度１０℃／分で４０℃まで降温させ、次いで直ちに加熱速度１０℃／分で融解ピーク終了時の温度よりも約３０℃高い温度まで昇温した時に得られるＤＳＣ曲線の融解ピーク（融解ピークが２つ以上存在する場合は融解ピーク面積のより大きいもの）の頂点温度をもって融点とする。尚、本明細書においては示差走査熱量測定装置として（株）島津製作所製の島津熱流束示差走査熱量計ＤＳＣ−５０を使用し、窒素ガス流入速度を毎分２０ｍｌとして上記測定を行って求められた融点を採用した。
【００２７】
前記接着層（１）の主成分として例示したポリエチレン系、ポリプロピレン系、エチレン−酢酸ビニル、ポリオレフィン系、ポリエステル系なる重合体は熱可塑性エラストマー、樹脂又はゴムであってもよい。また、前述の接着強度４９０ｍＮ／ｃｍ²以上を発現する該重合体は、例えば前記重合体に、ロシン、水添ロジン、重合ロジン、ロジンエステル等のロジン系樹脂、テルペン樹脂、水添テルペン樹脂、石油樹脂、水添石油樹脂、ポリスチレン等の粘着付与剤を５〜５０重量％添加すること、更に必要に応じてワックスを４０重量％以下添加することによる変性重合体として得ることができる。
また、芳香族ポリエステル系樹脂とポリスチレン系樹脂との混合物、融点が２００℃以下であるポリエステル系樹脂とポリスチレン系樹脂との混合物を接着層（１）に用いる場合には高い接着強度を示す混合比を両者の混合状態を表わすＰＩ値（相構造指数）によって選択することができる。ＰＩ値は下記式で定義される。
【数２】
ＰＩ値＝（η（ｐｓ）・φ（ｘ）／η（ｘ）・φ（ｐｓ）） （２）
前記式においてφ（ｐｓ）は接着層（１）中のポリスチレン系樹脂相の体積分率、η（ｐｓ）は１９０℃、剪断速度１００ｓｅｃ^-1におけるポリスチレン系樹脂の溶融粘度、φ（ｘ）は接着層（１）中の芳香族ポリエステル系樹脂相、またはポリエステル系重合体相の体積分率、η（ｘ）は１９０℃、剪断速度１００ｓｅｃ^-1における前記樹脂の溶融粘度である。
また、接着層（１）の厚みは、０．０１〜０．１ｍｍが好ましく、特に０．０１〜０．０８ｍｍが好ましい。０．０１ｍｍ未満では十分な接着強度が得られ難く、０．１ｍｍを越える場合はコスト高となってしまう。
本発明において好ましいＰＩ値の範囲は、０．７〜１．３、より好ましくは０．８〜１．２である。ＰＩ値の範囲が前記範囲を外れた場合は接着強度が低下するおそれがある。
本発明において、Ｐｅ／ＰＳ発泡体がポリオレフィン樹脂層、接着層（２）、芳香族ポリエステル系樹脂層、接着層（１）、ポリスチレン系樹脂発泡シート、接着層（３）、ポリオレフィン樹脂層の場合、接着層（１）としては、前記した樹脂の他に、ポリオレフィン樹脂、芳香族ポリエステル系樹脂及びポリスチレン系樹脂の混合物を主成分とするものが挙げられる。リサイクル性の点からポリオレフィン樹脂、芳香族ポリエステル系樹脂及びポリスチレン系樹脂の混合物を主成分とすることが好ましい。この場合、混合樹脂の重量混合比は、ポリオレフィン樹脂１０〜２５重量％、芳香族ポリエステル系樹脂１０〜２５重量％、ポリスチレン系樹脂８０〜５０重量％であることが各層の接着性の点から好ましい。
【００２８】
本発明において、フィルム状の芳香族ポリエステル系樹脂の上にフィルム状ポリオレフィン樹脂を積層接着する際、必ずしも接着層は必要ではない。その場合、例えば、フィルム状の芳香族ポリエステル系樹脂中にフィルム状ポリオレフィン樹脂と同一又は、熱融着可能な同種のポリオレフィン樹脂を含有することや、フィルム状ポリオレフィン樹脂中にフィルム状の芳香族ポリエステル系樹脂と同一又は熱融着可能な同種の芳香族ポリエステル系樹脂を含有する等が挙げられる。また、接着性を高める上では、接着層を介することが好ましい。
【００２９】
ポリオレフィン樹脂を芳香族ポリエステル上に積層させる際の接着層（以下、単に接着層（２）という）としては、通常用いられる接着剤の他に、リサイクル性の点からその主成分が芳香族ポリエステル系樹脂とポリオレフィン樹脂との混合物を主成分とするものが好ましく用いられる。ポリオレフィン樹脂に対する芳香族ポリエステル系樹脂の重量比が５：９５〜７０：３０、接着層の耐熱性向上の点から更に１０：９０〜６０：４０、特に１５：８５〜４５：５５であることが好ましい。なお、芳香族ポリエステル系樹脂とポリオレフィン樹脂の合計量は接着層（２）の全重量に対し５０重量％以上である。接着層（２）に使用されるポリオレフィン樹脂としては、接着層（２）上に積層されるポリオレフィン樹脂層に用いられるポリオレフィン樹脂と同一の樹脂、もしくは熱融着可能な同種のポリオレフィン樹脂が好ましく用いられる。
上記の中でも耐熱性の点から前記したフィルム状の芳香族ポリエステル系樹脂の上に積層接着されるポリオレフィン樹脂の例示と同様なポリオレフィン樹脂が好ましい。
【００３０】
前記した接着層（２）の混合樹脂中の芳香族ポリエステル系樹脂の量が５：９５を超えると接着層（２）と芳香族ポリエステル系樹脂層との間の接着強度は満足し得るものの接着層とポリオレフィン樹脂層との間の接着強度が不十分になる虞がある。一方、芳香族ポリエステル系樹脂の量が７０：３０より低くなると、接着層（２）とポリオレフィン樹脂層との間の接着強度は満足し得るものの、芳香族ポリエステル系樹脂層と接着層（２）との間の接着強度が不十分となる虞がある。
接着層（２）の厚みは０．０１５〜０．２ｍｍの範囲内で、厚みが増す程接着力が大きくなる傾向にあり、好ましくは０．０２〜０．１５ｍｍである。接着層（２）の厚みは芳香族ポリエステル系樹脂層の厚みの３〜５０％、好ましくは５〜４０％である。接着層（２）の厚みが３％よりも小さくなると、接着性が不十分となり、一方、５０％を超えると、コストアップの原因となる。
接着層（２）の芳香族ポリエステル系樹脂としては、前述した芳香族ポリエステル系樹脂を用いることができる。
【００３１】
尚、前記したフィルム状芳香族ポリエステル系樹脂の上にポリオレフィン樹脂を積層接着する際、接着層（２）を介して接着する場合は、フィルム状の芳香族ポリエステル系樹脂とポリスチレン系樹脂からなる発泡シートとを接着する接着層のところで述べたＰＩ値（相構造指数）と同様に芳香族ポリエステル系重合体とポリオレフィン樹脂との間にもＰＩ値によって選択することができる。
本発明において好ましいＰＩ値の範囲は、０．７〜１．３、より好ましくは０．８〜１．２である。ＰＩ値の範囲が前記範囲を外れた場合は接着強度が低下する虞がある。本発明において、少なくとも片面側がポリオレフィン樹脂層となる構成の場合、リサイクル性の点から接着層は、Ｐｅ／ＰＳ発泡体を溶融した混合樹脂を用いることが好ましい。
前記混合樹脂は、接着層を構成する樹脂の主成分であり、接着層全重量に対して２５重量％以上、好ましくは３０重量％以上含まれているということである。
さらに、前記した相溶化成分や弾性成分として作用する添加剤を添加することができる。
【００３２】
また、本発明のＰｅ／ＰＳ発泡体においては、フィルム状芳香族ポリエステル系樹脂の上にフィルム状ポリオレフィン樹脂を積層し、その他方の面に接着層（以下、単に接着層（３）とも言う）を介して、フィルム状ポリオレフィン樹脂を積層することができる。この両面にポリオレフィン樹脂が積層されたＰｅ／ＰＳ発泡体は、耐熱性及び耐折性が向上する点で好ましい。
積層するフィルム状ポリオレフィン樹脂の基材樹脂及び厚さは、前記したフィルム状芳香族ポリエステル系樹脂の上に積層接着するフィルム状ポリオレフィン樹脂と同じである。
その際、接着層（３）としては、ポリスチレン系樹脂とポリオレフィン樹脂との混合物を主成分とするもの、ポリオレフィン樹脂、芳香族ポリエステル系樹脂及びポリスチレン系樹脂の混合物を主成分とするものが挙げられる。上記の中でも、リサイクル性の点からポリオレフィン樹脂、芳香族ポリエステル系樹脂及びポリスチレン系樹脂の混合物を主成分とするものが好ましい。
この場合、混合樹脂の重量混合比は、ポリオレフィン樹脂１０〜２５重量％、芳香族ポリエステル系樹脂１０〜２５重量％、ポリスチレン系樹脂８０〜５０重量％であることが各層の接着性の点から好ましい。
更にそれらに必要に応じて相溶化成分や弾性成分として作用する添加剤を添加し、ポリスチレン系樹脂からなる発泡体とポリオレフィン樹脂との接着強度が４９０ｍＮ／ｃｍ以上の接着性が発現されるものが挙げられる。尚、前記接着層（３）の主成分とは、接着層（３）全重量に対し２５重量％以上、好ましくは３０重量％以上含まれているということである。
【００３３】
本発明のフィルム状の芳香族ポリエステル系樹脂層、接着層、ポリスチレン系樹脂発泡体が順に積層されたＰｅ／ＰＳの発泡体において接着層は、多層であってもかまわない。例えば、ポリスチレン系樹脂発泡体側にポリスチレン系樹脂層を有する多層の接着層があることにより押出時における発泡体側の樹脂温度を低くすることができ、それにより発泡体層の連続気泡率を低くすることができる。さらに、この多層の接着層であればＰｅ／ＰＳの発泡体におけるフィルム状の芳香族ポリエステル系樹脂を内面側とした容器とすれば食する際、割りばし、フォーク等のつきさしに対して強度を向上させることができる。
ポリスチレン系樹脂層は、特に限定されるものではないが、耐衝撃性の強いハイインパクトポリスチレン等のゴム変性ポリスチレン、スチレン−ブタジエン−スチレンブロック共重合体、スチレン−イソプレン−スチレンブロック共重合体等のスチレン−共役ジエンブロック共重合体が好適である。また必要に応じてこれらをポリスチレン樹脂に混合したものや、ポリスチレン樹脂に適宜ゴム、エラストマーを加えたものも好適である。
さらに、前記したポリスチレン系樹脂に押出の際、樹脂温度を低く調整するためにポリオレフィン樹脂を添加することもできる。その際の添加量としては、ポリスチレン系樹脂層に対して４０重量％以下が好ましく、３０〜５重量％が特に好ましい。添加量が４０重量％を越えるとポリスチレン系樹脂発泡体との接着性が低下する。
その際、ポリスチレン系樹脂層の厚みは、０．０５〜０．２ｍｍが好ましい。該厚みが０．０５ｍｍ未満では、前記した効果が得られ難く、該厚みが０．２ｍｍを超える場合では、コスト高となってしまう。
【００３４】
本発明のＰｅ／ＰＳの発泡体は、以下の方法で製造することができる。
フィルム状の芳香族ポリエステル系樹脂、接着層（１）ポリスチレン系樹脂からなる発泡体が順に積層している場合の代表的な方法としては、例えば（イ）押出機により単層のポリスチレン系樹脂発泡体を製造し、その後、この発泡体に対して、製造ライン上または別ラインで、別の押出機より共押出法により芳香族ポリエステル系樹脂と接着層（１）とを積層したシートを熱ロール等を通して積層接着する方法、（ロ）押出機により共押出法によって発泡体の少なくとも片面に接着層（１）を設けたものを製造し、その後、この発泡体に対して、製造ライン上または別ラインで、芳香族ポリエステル系樹脂を別な押出機より押出して積層接着する方法、（ハ）押出機により共押出法によって発泡体の少なくとも片面に接着層（１）を設けたものを製造し、その後、製造ライン上または別ラインで、芳香族ポリエステル系樹脂フィルムを熱ロール等を通して積層接着する方法、（ニ）発泡体、接着層（１）及び芳香族ポリエステル系樹脂の順に全てを共押出法によって積層接着する方法、（ホ）押出機により単層の発泡体を製造し、その後、この発泡体に対して、製造ライン上または別ラインで、別の押出機より押出された接着層（１）を介して更に別の押出機より押出された芳香族ポリエステル系樹脂を積層接着する方法、（ヘ）押出機により単層の発泡体を製造し、その後、この発泡体に対して、製造ライン上または別ラインで、別の押出機より押出された接着層（１）を介して芳香族ポリエステル系樹脂フィルムを積層接着する方法、（ト）押出機により単層の発泡体を製造し、その後、この発泡体に対して、製造ライン上または別ラインで、別の押出機より共押出法により押出された芳香族ポリエステル系樹脂と接着層（１）との積層物を積層接着する方法等がある。
（ロ）、（ハ）、（ニ）の方法によって製造する場合、接着層（１）の押出し時の樹脂温度は、発泡体の押出し時の樹脂温度プラス２０℃以下好ましくは該樹脂温度プラス１０℃以下であることが望ましい。該樹脂温度プラス２０℃を越えると発泡体の連続気泡率が大きくなるおそれがある。尚、接着層（１）の押出し時の樹脂温度の下限は溶融押出しが可能な温度であることは言うまでもない。また、発泡体に積層する芳香族ポリエステル系樹脂の溶融粘度は特に限定されるものではないが、共押出方法を考慮した場合、発泡体に使用されるポリスチレン系樹脂に近い溶融粘度であることが望ましく、好ましくはポリスチレン系樹脂の４分の１以上４倍未満の範囲である。上記（イ）〜（ト）の積層接着方法のうち（ニ）の方法は、他の方法に比べて工程がシンプルで低コスト化が可能であり好ましい。
さらに、芳香族ポリエステル系樹脂層の上にポリオレフィン樹脂層を積層接着する場合は、前記した（イ）〜（ト）と同じようにポリオレフィン樹脂層又は、接着層（２）とポリオレフィン樹脂層とをさらに積層接着する方法が挙げられる。
なかでも目的とする順に全てを共押出法による方法が他の方法に比べて工程がシンプルで低コスト化が可能であり好ましい。
【００３５】
本発明の接着層には、必要に応じて着色剤を接着層に対して２０重量％未満の量で添加することができる。
本発明で用いられる着色剤としては、例えば、黒色、灰色、茶色、黄色、赤色、桃色、緑色、青色等の着色顔料や染料が挙げられる。上記の中でも耐熱性の点から顔料が好ましい。顔料としては有機顔料、無機顔料等が挙げられる。有機顔料としては、アゾ顔料、銅フタロシアニン顔料等が挙げられる。無機顔料としては、チタンホワイト、黄鉛、カドミ顔料、弁柄、カーボンブラック等が挙げられる。
また、着色剤をそのまま押出機に投入しても構わないが、取扱いや作業性、樹脂に添加する際の分散性を考慮しマスターバッチ法が好ましい。その際、マスターバッチにおける着色剤の添加量はマスターバッチの基材樹脂１００重量部に対し１〜７０重量部、好ましくは３０〜６０重量部である。
本発明においてＰｅ／ＰＳ発泡体の最外層は、無色であっても接着層と同一又は同系色の色でも構わない。最外層を無色にした場合、特に食品と接触する容器の内側面が無色であると食品に着色剤が接することがないため好ましい。また、最外層を接着層（１）又は接着層（３）と同一又は同系色の色とした場合、接着層の色の補足ができる。
また、本発明の接着層に、耐熱性向上を目的として、例えば、ガラス転移点が１００℃以上の芳香族ポリエステル系樹脂、融点１２５℃以上のポリオレフィン樹脂や無機又は有機フィラーを接着層に添加することができる。
【００３６】
本発明のＰｅ／ＰＳ発泡体は、Ｐｅ／ＰＳ発泡体の不良品、成形不良品及び成形後の抜きカス等を再溶融して発泡体層の原料又は／及び接着層の原料として再利用できるがフィルム状の芳香族ポリエステル系樹脂の上又は接着層に、ポリオレフィン樹脂、ポリアミド系樹脂、ポリ塩化ビニリデン樹脂、エチレン酢酸ビニル共重合体けん化物等を用いたＰｅ／ＰＳ発泡体の場合、再溶融して発泡体層の原料として再利用する際、ポリオレフィン等の含有量によっては発泡体層が連泡となりやすく、低密度の発泡体層が得られない虞れがあるため、接着層の原料として再利用することが好ましい。
尚、Ｐｅ／ＰＳ発泡体を再溶融して発泡体層又は接着層の原料として再利用する割合は、発泡体層の原料として再利用する場合は発泡体層の全樹脂量１００重量％としたとき、Ｐｅ／ＰＳ発泡体を再溶融した混合樹脂を発泡体層の全樹脂量の５〜４０重量％含有することが発泡性、リサイクル性の点から好ましい。また、接着層として再利用する場合は接着層の全樹脂量１００重量％としたとき、Ｐｅ／ＰＳ発泡体を再溶融した混合樹脂を接着層の全樹脂量の５〜７５重量％含有することが接着性、リサイクル性の点から好ましい。
【００３７】
本発明のＰｅ／ＰＳ発泡体は、これを加熱軟化させ、金型を使用し真空成形法及び／又は圧空成形法、更にはそれらを応用したマッチドモールド成形法、プラグアシスト成形法等の熱成形等を行なうことにより、主にトレイ、カップ、丼、弁当箱等に成形することができる。尚、Ｐｅ／ＰＳ発泡体を成形する場合、少なくとも容器等の成形体の内側に芳香族ポリエステル系樹脂積層面が又は内層側に位置するように成形することが好ましい。
【００３８】
【実施例】
次に本発明を実施例により更に具体的に説明する。
【００３９】
実施例１
押出機として、直径６５ｍｍと直径９０ｍｍの２台の押出機をタンデム型に連結して用い、その口金（ダイス）としては、直径８４ｍｍ、隙間間隔０．５ｍｍの円筒状スリットを有するものを用いた。
直径６５ｍｍの押出機で原料投入口よりポリスチレン系樹脂Ａ９６．９重量部および添加剤としてタルクを０．８重量部投入し、その押出機内で加熱混練し、約２００℃に調整された樹脂混合物に発泡剤Ａを２．３重量部を圧入し、次いで、直径９０ｍｍの押出機に供給し、樹脂温度１６５℃に調整して、口金より樹脂を押出した。
押出された円筒状発泡樹脂を、直径２００ｍｍの冷却された円筒に沿わせて引取り、その後切り開くことにより単層の発泡シート（厚み１．９ｍｍ）を得、これを巻き取った。
【００４０】
なお、前記ポリスチレン系樹脂Ａは、ＨＨ３２、出光石油化学（株）製のもので、その溶融粘度は２０４０Ｐａ・Ｓ、ビカット軟化点は１０１℃、密度は１．０５ｇ／ｃｍ³である。
前記タルクとしては、松村産業（株）製ハイフィラー＃１２を用いた。
前記発泡剤Ａとしては、ｎ−ブタン７０重量％とｉｓｏ−ブタン３０重量％からなるブタン混合物を用いた。
【００４１】
次に、得られた発泡シートとあらかじめ作製したポリエステル系樹脂Ｂフィルム０．０５ｍｍ（厚さ）と重合体Ｋ（変性エチレン−酢酸ビニル共重合体）０．０３ｍｍ（厚さ）からなる多層フィルムとを重合体Ｋを発泡シート側として１８０℃に加熱した熱ロールを通して熱ラミネートを行い多層発泡シートを得た。
なお、前記ポリエステル系樹脂Ｂとしては、イーストマンケミカルジャパン（株）のイースターＰＥＴＧ６７６３、荷重４．９ｋＮでの流動開始温度が１４７℃、溶融粘度５０００Ｐａ・Ｓ、密度１．２６ｇ／ｃｍ³を用い、前記重合体Ｋ（変性エチレン−酢酸ビニル共重合体）としては、メルセンＭＸ２８、溶融粘度２７０Ｐａ・Ｓ、密度０．９４ｇ／ｃｍ³、融点１１７℃、東ソー（株）製を用いた。
【００４２】
実施例２
押出機として、直径６５ｍｍと直径９０ｍｍの２台の押出機をタンデム型に連結して用い、その口金（ダイス）としては、直径８４ｍｍ、隙間間隔０．５ｍｍの円筒状スリットを有するものを用いた。
直径６５ｍｍの押出機で原料投入口よりポリスチレン系樹脂Ｄ９７．３重量部および添加剤としてタルク（商品名：ハイフィラー＃１２）を０．９重量部投入し、その押出機内で加熱混練し、約２００℃に調整された樹脂混合物に発泡剤Ａを１．８重量部を圧入し、次いで、直径９０ｍｍの押出機に供給し、樹脂温度１６５℃に調整して、口金より樹脂を押出した。
押出された円筒状発泡樹脂を、直径２００ｍｍの冷却された円筒に沿わせて引取り、その後切り開くことにより単層の発泡シートを（厚み１．５ｍｍ）得、これを巻き取った。
なお、前記ポリスチレン系樹脂Ｄは、ＨＨ３０、出光石油化学（株）製のもので、その溶融粘度１５００Ｐａ・Ｓ、ビカット軟化点は９８℃、密度は１．０５ｇ／ｃｍ³である。
次に、得られた発泡シートに、接着層（１）として幅７００ｍｍのＴダイスを装着した直径６５ｍｍの押出機より樹脂温度２３０℃とした重合体Ｃ（変性エチレン−酢酸ビニル共重合体）０．０３ｍｍ（厚さ）を押出し、該接着層を介してあらかじめ作製したポリエステル系樹脂Ｂからなる０．０５ｍｍ（厚さ）のフィルムを、発泡シートに積層接着した多層発泡シートを得た。
なお、前記重合体Ｃ（変性エチレン−酢酸ビニル共重合体）としてはヒロダイン（株）の商品名：ヒロダイン７５６０、溶融粘度２７０Ｐａ・Ｓ・密度０．９２５ｇ／ｃｍ³、融点１００℃を用いた。
【００４３】
実施例３
押出機として、直径６５ｍｍと直径９０ｍｍの２台の押出機をタンデム型に連結して用い、その口金（ダイス）としては、直径８４ｍｍ、隙間間隔０．５ｍｍの円筒状スリットを有するものを用いた。
直径６５ｍｍの押出機で原料投入口よりポリスチレン系樹脂Ｅ９６重量部および添加剤としてタルク（商品名：ハイフィラー＃１２）を０．６重量部投入し、その押出機内で加熱混練し、約２００℃に調整された樹脂混合物に発泡剤Ａを３．４重量部を圧入し、次いで、直径９０ｍｍの押出機に供給し、樹脂温度１６３℃に調整して、口金より樹脂を押出した。
押出された円筒状発泡樹脂を、直径２００ｍｍの冷却された円筒に沿わせて引取り、その後切り開くことにより単層の発泡シートを得（厚み２．０５ｍｍ）、これを巻き取った。
なお、前記ポリスチレン系樹脂Ｅは、商品名Ｇ９００１、エイ・アンド・エムスチレン（株）製のもので、その溶融粘度は２６８０Ｐａ・Ｓ、ビカット軟化点は１１０℃以上、密度は１．１ｇ／ｃｍ³である。
次に、直径５０ｍｍの押出機より樹脂温度２３０℃とした重合体Ｃ（変性エチレン−酢酸ビニル共重合体）と、直径５０ｍｍの押出機より樹脂温度２７０℃としたポリエステル系樹脂Ｂとを幅７００ｍｍのＴダイスに供給しダイス中で両者を合流させ多層化した後、Ｔダイスより押出ラミネートし多層シートを得た。多層シートの各層の厚みはポリエステル系樹脂Ｂ０．０５ｍｍ（厚さ）、重合体Ｃ０．０５ｍｍ（厚さ）であった。
次に、この多層シートを前記発泡シートに重合体Ｃを発泡シート側として熱圧着して多層発泡シートを得た。
【００４４】
実施例４
発泡シート製造用の押出機として直径６５ｍｍと直径９０ｍｍの２台の押出機をタンデム型に連結して用いた。さらに、接着層（１）製造用としては直径４０ｍｍの押出機を用い、口金としては、直径８４ｍｍ、隙間間隔０．５ｍｍの円筒状スリットを有するものを用いた。
直径６５ｍｍの押出機の原料投入口より発泡シート製造用のポリスチレン系樹脂Ａ９８．１重量部及びタルク（商品名：ハイフィラー＃１２）１．２重量部を投入し、押出機内で加熱混練し、約２００℃に調整された樹脂混練物に対して発泡剤Ａを０．７重量部を圧入し、次いで、直径９０ｍｍの押出機に供給し、１６８℃の樹脂温度に調整した。一方、発泡シートに積層される接着層（１）を構成する重合体Ｃはこれを直径４０ｍｍの押出機より１５０℃の樹脂温度押出し、発泡シートの片面に重合体Ｃが積層されたものが得られるように供給し、ダイス内部で発泡性樹脂と合流させ共押出した。
押出された円筒状発泡樹脂を、直径２００ｍｍの冷却された円筒に沿わせて引取り、その後切り開くことにより、多層発泡シートを得（単層発泡シート厚み０．８６ｍｍ、接着層（１）厚み０．０８ｍｍ）、これを巻き取った。
得られた多層発泡シートに幅７００ｍｍのＴダイスを装着した直径６５ｍｍの押出機より樹脂温度２７０℃としたポリエステル系樹脂Ｂを押出して押出ラミネートを行い０．１ｍｍ厚みのフィルム状ポリエステル系樹脂Ｂが接着層（１）を介して積層接着された多層発泡シートを得た。
【００４５】
実施例５
発泡シート製造用の押出機として直径６５ｍｍと直径９０ｍｍの２台の押出機をタンデム型に連結して用いた。この場合、芳香族ポリエステル系樹脂層用の押出機としては直径５０ｍｍの押出機を、接着層（１）製造用としては直径４０ｍｍの押出機を用い、口金としては、直径８４ｍｍ、隙間間隔０．５ｍｍの円筒状スリットを有するものを用いた。
直径６５ｍｍの押出機の原料投入口より発泡シート製造用のポリスチレン系樹脂Ａ９８．６重量部及び気泡調整剤としてハイドロセロールＣＦ４０Ｓ（大日精化工業（株）製）を０．３重量部を投入し、押出機内で加熱混練し、約２００℃に調整された樹脂混練物に対して発泡剤Ａを１．１重量部を圧入し、次いで、直径９０ｍｍの押出機に供給し、１６７℃の樹脂温度に調整した。一方、発泡シートに積層される芳香族ポリエステル系樹脂Ｂはこれを直径５０ｍｍの押出機より２１５℃の樹脂温度に調整して押出し、接着層（１）を構成する樹脂はポリスチレン系樹脂Ｆ６０重量％とポリエステル系樹脂Ｇ４０重量％の混合物を用い、これを直径４０ｍｍの押出機より１５０℃の樹脂温度に調整して押出し、それぞれを発泡シートの片面に発泡シート側から接着層（１）を構成する樹脂、芳香族ポリエステル系樹脂の順に積層されたものが得られるように供給し、ダイス内部で発泡性樹脂と合流させ共押出した。
押出された円筒状発泡樹脂を、直径２００ｍｍの冷却された円筒に沿わせて引取り、その後切り開くことにより、多層の発泡シートを得、これを巻き取った。
この多層の発泡シートにおいて、その単層の発泡シートの厚みは１．４ｍｍ、接着層（１）の厚みは０．０４ｍｍ、フィルム状芳香族ポリエステル系樹脂の厚みは０．０５ｍｍである。得られたシートに幅７００ｍｍのＴダイスを装着した直径６５ｍｍの押出機より樹脂温度２６０℃としたポリスチレン系樹脂Ｌを押出して押出ラミネートを行い片面に厚さ０．１５ｍｍのフィルム状のポリスチレン系樹脂が積層接着され、他方の片面に接着層（１）を介してフィルム状の芳香族ポリエステル系樹脂が積層接着された多層の発泡シートを得た。
なお、前記ポリスチレン系樹脂Ｆは、商品名スタイロンＨ８６０１、エイ・アンド・エム スチレン（株）製のもので、その溶融粘度は９８０Ｐａ・Ｓ、ビカット軟化点は９６℃、密度は１．０５ｇ／ｃｍ³である。
前記ポリエステル系樹脂Ｇは、商品名：ビオノーレ＃１９０３、昭和高分子（株）製のもので、その溶融粘度は６２０Ｐａ・Ｓ、融点は１１４℃、密度は１．２６ｇ／ｃｍ³である。
前記ポリスチレン系樹脂Ｌは、商品名ＲＱ３０１、電気化学工業（株）製のもので、その溶融粘度は１６５０Ｐａ・Ｓ、ビカット軟化点は９７℃、密度は１．０５ｇ／ｃｍ³である。
【００４６】
実施例６
接着層（１）を重合体Ｈ（変性ポリオレフィン系重合体）とした以外は実施例５と同じ方法にて多層の発泡シートを得た。
なお、前記重合体Ｈ（変性ポリオレフィン系重合体）は、商品名：アドマーＳＦ７３０、三井化学（株）製のもので、その溶融粘度は１２８０Ｐａ・Ｓ、ビカット軟化点は５４℃、融点は１２０℃、密度は０．９ｇ／ｃｍ³である。
【００４７】
実施例７
接着層（１）を重合体Ｈ５０重量％とポリスチレン系樹脂Ｆ５０重量％の混合物とした以外は実施例５と同じ方法にて多層の発泡シートを得た。
【００４８】
実施例８
接着層（１）を重合体Ｊ（変性ポリエステル系重合体）とした以外は実施例５と同じ方法にて多層の発泡シートを得た。
なお、前記重合体Ｊ（変性ポリエステル系重合体）は、商品名：アロンメルトＰＥＳ−１１、東亜合成（株）製のもので、その溶融粘度は１５０Ｐａ・Ｓ、ビカット軟化点は７０℃、融点は１１０℃、密度は１．２ｇ／ｃｍ³である。
【００４９】
実施例９
接着層（１）を重合体Ｋとした以外は実施例５と同じ方法にて多層の発泡シートを得た。
【００５０】
実施例１０
接着層（１）に赤色として（レジノカラー工業（株）製、ＳＢＦ−Ｔ−４５８６（酸化鉄））を６重量％添加した以外は実施例９と同じ方法にて赤色に着色された多層の発泡シートを得た。
【００５１】
実施例１１
実施例１と同様に単層の発泡シート（厚み２．１ｍｍ）を得、これを巻き取った。
次に、得られた発泡シートとあらかじめＴダイス幅７００ｍｍの押出機で作製したポリエステル系樹脂Ｂフィルム０．０２ｍｍ（厚さ）と、ポリスチレン系樹脂Ａ６０重量％とポリエステル系樹脂Ｂ４０重量％の混合物からなる樹脂層０．０２ｍｍ（厚さ）と、ポリスチレン系樹脂Ｍからなる樹脂層０．０７ｍｍ（厚さ）からなる多層の接着層（１）を有する多層フィルムを接着層（１）のポリスチレン系樹脂Ｍからなる樹脂層を発泡シート側として１８０℃に加熱した熱ロールを通して熱ラミネートを行い多層発泡シートを得た。
尚、ポリスチレン系樹脂Ｍでは、日本ポリスチレン株式会社製耐衝撃ポリスチレン（ＨＩＰＳ）「Ｈ６４０Ｎ（密度１．０５ｇ／ｃｍ³）」を用いた。
【００５２】
実施例１２
実施例１１と同様に多層発泡シートを得、これを巻き取った。
次に、得られた多層発泡シートにＴダイスの押出機より樹脂温度２６０℃としたポリスチレン系樹脂Ｍを押出して押出ラミネートを行ない接着層が積層されている他方の面に厚さ０．１５ｍｍのフィルム状のポリスチレン系樹脂が積層接着された多層発泡シートを得た。
【００５３】
比較例１
ポリエステル系樹脂としてポリエステル系樹脂Ｂの替わりにポリエステル系樹脂Ｐを用いた以外は実施例１と同様にして多層の発泡シートを得た。なお、前記ポリエステル系樹脂Ｐは日本ユニペット（株）製、ＲＴ５４３、荷重４．９ｋＮの流動開始温度が２５５℃、１９０℃で未溶融のため溶融粘度測定不可、密度１．２６ｇ／ｃｍ³である。
【００５４】
比較例２
ポリエステル系樹脂としてポリエステル系樹脂Ｂの替わりにポリエステル系樹脂Ｐを用い、直径５０ｍｍの押出機より２７０℃の樹脂温度に調整して押出し以外は実施例６と同様にして多層の発泡シートを得た。
【００５５】
次に、前記実施例及び比較例で得た各発泡シートの厚みや接着強度等の物性を測定するとともに、その押出発泡性を評価し、さらにその耐油性成形性及び耐熱性を下記のようにして評価した。その結果を表１〜表３に示す。
【００５６】
（耐油性）
２５ｍｍ×４０ｍｍの多層の発泡シートの中央部（多層の発泡シートの芳香族ポリエステル系樹脂積層面の中央部）に米炊飯調味油（フレッシュロールホワイト、（株）ローリング社製）を０．０２５ｍｌ滴下し均一に延ばした後、８０℃で５分間加熱し、加熱前後の発泡シート変化を調べた。
○：変化なし
×：シート表面に侵食有り
【００５７】
（成形性）
実施例及び比較例にて得られた多層の発泡シートを単発成形機（三和興業株式会社製のＰＬＡＶＡＣ−ＦＥ３６ＨＰ型）にて開口部形状が直径１５０ｍｍ、底部直径１２０ｍｍ、深さ６０ｍｍ又は３０ｍｍの円錐台形状の容器成形用金型を取り付けて（芳香族ポリエステル系樹脂積層面が容器の内側となるようにして）真空成形を行なった。尚、この成形テストにおいては、上ヒーターの電圧調整器の４０個のダイヤル目盛りはすべて３０に設定し、下ヒーターの電圧調整器の６個のダイヤル目盛りはすべて４０に設定して行った。得られた成形体の外観にて成形性（熱成形性）の評価を行なった。
◎：絞り比０．９において金型再現性及び外観共に良好
○：絞り比０．４（深さ６０ｍｍ）において金型再現性及び外観共に良好、
絞り比０．９では金型再現性及び／又は外観が不良
△：絞り比０．２（深さ３０ｍｍ）において金型再現性及び外観共に良好、
絞り比０．４では金型再現性及び／又は外観が不良
×：絞り比０．２でも金型再現性及び／又は外観が不良
尚、上記絞り比０．９については開口部形状が直径９５ｍｍ、底部直径７０ｍｍ、深さ１０５ｍｍの円錐台形状の容器成形用金型を用いた。
【００５８】
前記試験の結果、実施例の多層の発泡シートはいずれも連続気泡率が低く、加熱真空成形においては金型再現性の良好な深絞り成形体を得ることができた。また接着強度も強いものであった。
一方、比較例の多層の発泡シートは加熱真空成形においては金型再現性の良好な深絞り成形体を得ることができなかった。また、比較例２のものは、多層の発泡シートが得られても連続気泡率が高いものであった。また、比較例１及び２に示したように発泡シートに接着層を介してフィルム状で積層する芳香族ポリエステル系樹脂を荷重４．９ｋＮでの流動開始温度が２００℃を超える芳香族ポリエステル系樹脂とした多層の発泡シートは、加熱真空成形においてポリスチレン系樹脂発泡シートの成形条件ではポリエステル部が十分伸びず、成形体表面にシワが発生した。
【００５９】
（耐熱性）
前記熱成形試験にて得られた絞り比０．４の成形体に沸騰したお湯を深さ５０ｍｍになる量を５秒間で注ぎその後４分間蓋をせずに放置しその後お湯を捨て、容器内部の外観を観察した。
○：変化なし
△：シート表面ポリエステル系樹脂層の剥離有り
【００６０】
（接着強度）
接着強度は得られたシートより幅２５ｍｍの試験片を切り出し、ＪＩＳ Ｚ０２３７に準拠し、剥離速度３００ｍｍ／ｍｉｎの条件にて９０°剥離試験にて測定した値（ｍＮ／２５ｍｍ）を２．５で割算して求め、ポリエステル系樹脂と接着層、接着層と発泡体との接着強度（ｍＮ／ｃｍ）のいずれか低い値を採用した。
【００６１】
（各樹脂の溶融粘度）
前記各樹脂の溶融粘度は剪断速度１００ｓｅｃ^-1の条件下、ノズル径（Ｄ）が１．０ｍｍ、Ｌ／Ｄ＝１０（Ｌはノズル長：ｍｍ）のノズルを用い、樹脂温度１９０℃の条件にてチアスト社製レオビス２１００で測定した。
（多層発泡シート、ポリエステル系樹脂等の厚み）
多層発泡シートの厚み方向垂直断面の任意の２０ヶ所より厚みを測定しその平均値を採用した。尚、厚み測定は顕微鏡写真を使用し拡大倍率換算して各厚みを求めた。
（多層発泡シートの坪量）
Ｐｅ／ＰＳ発泡体より縦２０ｃｍ×横２０ｃｍ×Ｐｅ／ＰＳ発泡シートの厚みの試験片を切り出し、試験片重量（ｇ）を測定し、その値を２５倍することにより坪量（ｇ／ｍ²）を算出した。
（多層発泡シートの密度）
多層発泡シートの坪量測定と同様の試験片を作成し、試験片重量（ｇ）を測定し、縦２０ｃｍ×横２０ｃｍ×Ｐｅ／ＰＳ発泡シートの厚み（ｃｍ）で求められる試験片体積（ｃｍ³）で試験片重量（ｇ）を割ることにより求めた。
（ポリスチレン系樹脂発泡シートの密度）
多層発泡シートの坪量（ｇ／ｍ²）から、ポリエステル系樹脂、接着層（１）及びポリスチレン系樹脂の各々の坪量（ｇ／ｍ²）（各々の密度及び厚みより算出される）を引き算して求められる発泡シートのみの坪量（ｇ／ｍ²）を単位換算して坪量（ｇ／ｃｍ²）とし、該坪量（ｇ／ｃｍ²）を発泡シートのみの厚み（ｃｍ）で割り算することにより求めた。
（流動開始温度）
（株）島津製作所製島津フローテスタＣＦＴ−５００Ａ形を用いて、ダイ寸法直径１．０ｍｍ×長さ１０．０ｍｍ、荷重４．９ｋＮ、昇温速度１０℃／ｍｉｎで等速等温試験を行った時にピストンの変位が始まる温度を測定した。
【００６２】
【表１】

【００６３】
【表２】

【００６４】
【表３】

【００６５】
実施例１３
ポリスチレン系樹脂発泡体の一方の面に、接着層（１）を介してポリエステル系樹脂層を積層し、その上に接着層（２）を介してポリオレフィン樹脂層を積層するとともに、そのポリスチレン系樹脂発泡体の他方の面に、接着層（３）を介してポリオレフィン樹脂層を積層した構造の多層発泡体を以下のようにして製造した。
【００６６】
（押出機）
ポリスチレン系樹脂発泡体製造用押出機としては、直径９０ｍｍと直径１２０ｍｍの２台の押出機とタンデム型に連結して用いた。
芳香族ポリエステル系樹脂層形成用押出機としては、直径４５ｍｍの押出機を用いた。
ポリオレフィン樹脂層形成用押出機としては、直径６５ｍｍの押出機を用いた。
接着層（２）形成用押出機としては、直径６５ｍｍの押出機を用いた。
接着層（１）と接着層（３）を形成するための押出機としては、直径６５ｍｍの押出機を用いた。
各押出機より押出される樹脂流を合流させ、円筒状に押出するための口金としては、直径１３５ｍｍ、隙間間隔０．３ｍｍの円筒状スリットを有するものを用いた。
【００６７】
（多層発泡体の製造）
直径９０ｍｍの押出機の原料投入口より発泡体用ポリスチレン系樹脂Ａ９８．６重量部及び気泡調整剤としタルク（商品名：ハイフィラー＃１２）を１．３重量部投入し、その押出機内で加熱混練するとともに、この約２００℃に調整された混練物に対して発泡剤Ａを１．０重量部圧入し、次いで、直径１２０ｍｍの押出機に供給し、樹脂温度を１６５℃に調整した。
【００６８】
２つの直径６５ｍｍの押出機の各々に、接着層（１）と接着層（３）形成用樹脂組成物として、ポリオレフィン樹脂Ｒ１３．７重量％、芳香族ポリエステル系樹脂Ｂ１２．３重量％、ポリスチレン系樹脂Ａ４９重量％、添加剤Ｘ５重量部及び重合体Ｋ２０重量％を添加したものを供給し、加熱混練し、その樹脂温度を１７０℃に調整した。
直径４５ｍｍの押出機に、芳香族ポリエステル系樹脂Ｂを供給し、加熱混練し、その樹脂温度を２００℃に調整した。
直径６５ｍｍの押出機に、接着層（２）形成用の芳香族ポリエステル系樹脂Ｂ７０重量％とポリオレフィン樹脂Ｒ３０重量％との混合物を供給し、加熱混練し、その樹脂温度を１７０℃に調整した。
直径６５ｍｍの押出機に、ポリオレフィン樹脂Ｑを供給し、加熱混練し、その樹脂温度を１８５℃に調整した。
前記各押出機内の樹脂を、ダイス内部で合流させ、口金のスリットから共押出して、ポリオレフィン樹脂層、接着層（２）、芳香族ポリエステル系樹脂層、接着層（１）、ポリスチレン系樹脂発泡体層、接着層（３）、ポリオレフィン樹脂層の順に積層された円筒状発泡樹脂を、直径３３５ｍｍの冷却された円筒に沿わせて引取り、その後切り開くことにより積層発泡体を得て、これを巻き取った。
得られた積層発泡体についての諸物性を表４に示した。
【００６９】
実施例１４
接着層（１）、（２）、（３）に黄色としてポリコール興業（株）製ＥＰＳ−Ｅ−４０５１８を混合樹脂９２重量％に対して８重量％の割合で添加した以外は実施例１３と同様に積層発泡体を得た。
【００７０】
実施例１５
ポリオレフィン樹脂層を構成する樹脂としてポリオレフィン樹脂Ｑ８０重量％及びポリオレフィン樹脂Ｖ２０重量％の混合樹脂を用いた。
接着層（２）は、ポリオレフィン樹脂Ｑ６７．２重量％、芳香族ポリエステル系樹脂Ｂ２８．８重量％及び黒色としてポリコール興業（株）製ＥＳＨ−Ｋ−４４３９２を４重量％を添加したものを用いた。
接着層（１）、（３）は、ポリオレフィン樹脂Ｑ１０．４重量％、ポリオレフィン樹脂Ｖ２．６重量％、芳香族ポリエステル系樹脂Ｂ１１．６重量％、ポリスチレン系樹脂Ａ４６．４重量％、添加剤Ｘ５．０重量％、黒色としてポリコール興業（株）製ＥＳＨ−Ｋ−４４３９２を４．０重量％及び重合体Ｋ２０．０％を添加したものを用いた。
ポリスチレン系樹脂発泡体層は、ポリスチレン系樹脂Ａ９９重量％、黒色としてポリコール興業（株）製ＥＳＨ−Ｋ−４４３９２を１．０重量％添加した以外は実施例１３と同様に積層発泡体を得た。
【００７１】
実施例１６
ポリオレフィン樹脂層を構成する樹脂にポリオレフィン樹脂Ｔ（高密度ポリエチレン）を用いた。
接着層（２）はポリオレフィン樹脂Ｔ３０重量％と芳香族ポリエステル系樹脂Ｂ７０重量％を用いた。
接着層（１）、（３）はポリオレフィン樹脂Ｔ１４重量％、芳香族ポリエステル系樹脂Ｂ７．１重量％、ポリスチレン系樹脂Ａ３８．９重量％、重合体Ｋ４０重量％を添加したものを用いた。
ポリスチレン系樹脂発泡体層は、ポリスチレン系樹脂Ａ９８重量％及び気泡調整剤としてタルク（商品名：ハイフィラー＃１２）を１．３重量％投入し、その押出機内で加熱混練するとともに、この約２００℃に調整された混練物に対して発泡剤Ａを０．７重量％圧入し、次いで、直径１２０ｍの押出機に供給し、樹脂温度を１６５℃に調整した。ポリスチレン系樹脂発泡体層の密度を０．１９ｇ／ｃｍ³、厚さ０．７４ｍｍとし、実施例１３と同様な方法で積層発泡体を得た。
【００７２】
実施例１７
ポリオレフィン樹脂層を構成する樹脂にポリオレフィン樹脂Ｓ（高密度ポリエチレン）を用いた。
接着層（２）のポリオレフィン樹脂Ｓ３０重量％と芳香族ポリエステル系樹脂Ｂ７０重量％を用いた。
接着層（１）、（３）はポリオレフィン樹脂Ｓ１４重量％、芳香族ポリエステル系樹脂Ｂ７．１重量％、ポリスチレン系樹脂Ｗ３８．９重量％、重合体Ｋ４０重量％を添加したものを用いた。
ポリスチレン系樹脂発泡体層は、ポリスチレン樹脂Ｗ９８重量％及び気泡調整剤としてタルク（商品名：ハイフィラー＃１２）を１．３重量％投入し、その押出機内で加熱混練するとともに、この約２００℃に調整された混練物に対して発泡剤Ａを０．７重量％圧入し、次いで、直径１２０ｍｍの押出機に供給し、樹脂温度を１６５℃に調整した以外は実施例１６と同様に積層発泡体を得た。
なお、前記ポリオレフィン樹脂Ｑは、チッソ（株）製「Ｆ８１８８」（プロピレン−エチレンランダム共重合体、融点１４５．７℃、密度０．９ｇ／ｃｍ³、溶解粘度６３０Ｐａ・Ｓ（１９０℃）、ビガット軟化点１２０℃以上である。
前記ポリオレフィン樹脂Ｒは、日本ポリオレフィン（株）製「ＰＭ７６１Ａ」（プロピレン−エチレンブロック共重合体、融点１６３．４℃、密度０．９ｇ／ｃｍ³、溶解粘度６６０Ｐａ・Ｓ（１９０℃）、ビガット軟化点１３０℃である。
前記ポリオレフィン樹脂Ｓは、出光石油化学（株）製「３１０Ｅ」（高密度ポリエチレン、融点１３６℃、密度０．９６５ｇ／ｃｍ³、溶解粘度１６５０Ｐａ・Ｓ（１９０℃）、ビガット点１３０℃である。
前記ポリオレフィン樹脂Ｔは、東ソー（株）製「ニポロンハード４０００」（高密度ポリエチレン、融点１３５℃、密度０．９６４ｇ／ｃｍ³、溶解粘度６３０Ｐａ・Ｓ（１９０℃）、ビガット点１３０℃である。
前記したポリオレフィン樹脂Ｖは、出光石油化学社製、「２１０ＪＺ」（高密度ポリエチレン、溶融粘度８２０Ｐａ・Ｓ、融点１３５．６℃、密度０．９６８ｇ／ｃｍ³、ビカット軟化点１２９℃）
前記ポリスチレン系樹脂Ｗは、東洋スチレン（株）製「トーヨースチロールＧＰ ＴＦ−２−３１１」（スチレン−メタクリル酸共重合体、ビガット軟化点１１０℃以上、密度１．０５ｇ／ｃｍ³）である。
前記添加剤Ｘは、旭化成工業（株）製「タフテックＨ１１４１」（水素添加スチレンブタジエンスチレンエラストマー、密度０．９１ｇ／ｃｍ³）である。
実施例１１〜１７で得られたＰｅ／ＰＳ発泡体における各接着層の接着性を確認するため前記した接着強度と同じ方法で行なった結果、すべて材料破壊となった。表４の耐油性、成形性、体熱性の評価は表１〜３と同じ方法で行った。また、表４の各層の厚み、多層発泡シート全体の坪量及びポリスチレン系樹脂発泡シートの密度は、前記した通りに行った。
【００７３】
【表４】

【００７４】
実施例１８
発泡シート製造用の押出機として直径６５ｍｍと直径９０ｍｍの２台の押出機をタンデム型に連結して用いた。芳香族ポリエステル系樹脂層用の押出機としては直径５０ｍｍの押出機を、芳香族ポリエステル系樹脂層と発泡シート層との接着層（１）用としては直径４０ｍｍの押出機を用いた。一方、他方の片面に積層するポリオレフィン樹脂層用としては直径５０ｍｍの押出機を、ポリオレフィン樹脂層と発泡シート層との接着層（３）用としては直径４０ｍｍの押出機を用いた。口金としては、直径８４ｍｍ、隙間間隔０．５ｍｍの円筒状スリットを有するものを用いた。
直径６５ｍｍの押出機の原料投入口より発泡シート製造用のポリスチレン系樹脂Ｅ９６重量部および添加剤としてタルク（松村産業（株）製ハイフィラー＃１２）を０．６重量部投入し、その押出機内で加熱混練し、約２００℃に調整された樹脂混合物に発泡剤Ａ２．１重量部を圧入し、次いで、直径９０ｍｍの押出機に供給し、樹脂温度１６３℃に調整した。一方、発泡シートに積層される芳香族ポリエステル系樹脂Ｂを、直径５０ｍｍの押出機より１７０℃の樹脂温度で押出し、芳香族ポリエステル系樹脂層と発泡シート層との接着層（１）用として芳香族ポリエステル系樹脂Ｂ５０重量％とポリスチレン系樹脂Ｅ５０重量％の混合樹脂を、直径４０ｍｍの押出機より１６８℃の樹脂温度で押出し、他方の片面に積層するポリオレフィン樹脂Ｎを、直径５０ｍｍの押出機より１６５℃の樹脂温度で押出し、ポリオレフィン樹脂層と発泡シート層との接着層（３）用としてポリオレフィン樹脂Ｎ３０重量％とポリスチレン系樹脂Ｅ７０重量％の混合樹脂を、直径４０ｍｍの押出機より１６７℃の樹脂温度で押出し、ダイス内部で合流させ共押出した。
押出された円簡状発泡樹脂を、直径２００ｍｍの冷却された円筒に沿わせて引き取り、その後切り開くことにより多層発泡シートを得、これを巻き取った。このシートの各層の厚みは芳香族ポリエステル系樹脂層０．０２４ｍｍ、接着層（１）０．０３５ｍｍ、発泡体層１．５６ｍｍ、接着層（３）０．０３９ｍｍ、ポリオレフィン樹脂Ｍ層０．０３１ｍｍであった。
前記したポリオレフィン系樹脂Ｎは５２０ＭＢ、出光石油化学（株）製の高密度ポリエチレンで、その溶融粘度は１９００Ｐａ・Ｓ、密度０．９６４ｇ／ｃｍ³、ビカット軟化点１３０℃、アイゾット衝撃値（−２０℃）３０ＫＪ／ｍ²である。
得られた多層発泡シートを前記した接着強度の方法でポリオレフィン樹脂層とポリスチレン系樹脂発泡シートとの接着強度を測定した結果、２１５６ｍＮ／ｃｍであった。
【００７５】
実施例１９
芳香族ポリエステル系樹脂層と発泡シート層との接着層（１）用としてポリオレフィン系樹脂Ｏを用いた他は実施例１８と同じ装置および原料を使用した。このシートの各層の厚みは芳香族ポリエステル系樹脂層０．０２４ｍｍ、接着層（１）０．０３５ｍｍ、発泡体層１．５６ｍｍ、接着層（３）０．０３９ｍｍ、ポリオレフィン樹脂Ｍ層０．０３１ｍｍであった。
前記したポリオレフィン系樹脂ＯはアクリフトＷＨ２０２ 住友化学工業株式会社製のエチレン−メタクリル酸メチル共重合体を用いた。
得られた多層発泡シートを前記した接着強度の方法でポリオレフィン樹脂層とポリスチレン系樹脂発泡シートとの接着強度を測定した結果、２１５６ｍＮ／ｃｍであった。
表５の低温耐衝撃性は下記のように評価した。
（低温耐衝撃性）
実施例１８で得られた多層発泡シートを単発成形機（三和興業株式会社製のＰＬＡＶＡＣ−ＦＥ３６ＨＰ型）にて容器外側をポリオレフィン樹脂層として開口部形状が縦１５０ｍｍ、横１２０ｍｍ、深さ３０ｍｍの容器（絞り比０．１９）成形用金型を取り付けて真空成形を行った。この容器に内容物として１５０ｇの水を入れ、開口部の蓋材にてシールする。その後−３５℃に２時間保持した後、室温（温度２３℃、湿度５５％）に取り出して２秒以内に高さ１００ｃｍからステンレス盤上に落下させた。このときの容器の破損状況を調べた。
○ 変化なしまたは容器へこみが入るがわれは発生せず。
× 容器に穴が開くまたは容器内側に亀裂が入る。
【００７６】
【表５】

【００７７】
【発明の効果】
本発明の、昇温速度１０℃／分で等速昇温試験を行ったときの荷重４．９ｋＮでの流動開始温度が２００℃以下のフィルム状の芳香族ポリエステル系樹脂とポリスチレン系樹脂発泡体との積層体は耐油、耐溶剤性、保香性、ガスバリア性に優れ、連続気泡率が低く、外観良好で、熱成形（とくに深絞り成形）に好適なものである。また、ヒートシール性（フィルム状の芳香族ポリエステル系樹脂を内側にして容器に成形した場合のトップシール性等）が特に良好なものとなる。さらに、フィルム状芳香族ポリエステル系樹脂の上にフィルム状ポリオレフィン系樹脂が積層されている場合、耐熱性が高い。その上、本発明の芳香族ポリエステル系樹脂積層ポリスチレン系樹脂発泡体又はその成形体は、目的に応じて発泡体層の原料又は接着層の原料として再利用することができ芳香族ポリエステル系樹脂積層ポリスチレン系樹脂発泡体の原料ロスが少ないものである。[0001]
BACKGROUND OF THE INVENTION
The present invention is a sheet or plate having excellent molding processability, recyclability, and solvent resistance, which is preferably used as a container material for food packaging mainly processed into trays, cups, lunch boxes, bowls, etc. The foam (hereinafter also simply referred to as a foam).
[0002]
[Prior art]
Conventionally, expanded polystyrene sheets have been thermoformed and widely used in various containers such as trays, lunch boxes, bowls, cups and the like. However, the expanded polystyrene sheet is inferior in oil resistance, solvent resistance, aroma retention, and gas barrier properties. In order to remedy the drawbacks of these expanded polystyrene sheets, a multilayer sheet in which a polyester film is bonded to one or both sides of the expanded polystyrene sheet has been studied. Japanese Utility Model Publication No. 59-188875 discloses expanded polystyrene. A multilayer sheet in which polyethylene terephthalate is bonded to one side or both sides of the sheet is disclosed in Japanese Utility Model Laid-Open No. 60-18961, and a multilayer sheet in which an unstretched polyethylene terephthalate film is bonded to one side or both sides of a foamed polystyrene sheet is studied. . However, the multilayer sheet described in the above publication still has a sufficient improvement in moldability, particularly deep drawability of 0.4 or more, particularly 0.8 or more of the drawing ratio (maximum depth of the molded product / maximum diameter of the molded product opening). It is the present situation that is not made.
On the other hand, in recent years, recycling of plastic containers is also desired, and the above-described multilayer sheet bonded with polyethylene terephthalate is urged to be recycled without exception.
As a method of recycling this multilayer sheet, (a) a method of peeling the polyethylene terephthalate part and the expanded polystyrene sheet part and recycling each of them, (b) a method of remelting the multilayer sheet and recycling it as a mixed resin, or ( C) A method of further fractionating the mixed resin obtained in the above (b) and recycling it as a component raw material is conceivable. However, the methods (a) and (c) are difficult in terms of the number of processes and equipment. In the end, the method (b) is the easiest to implement. However, it was not possible to produce a good foamed sheet by melting and using the mixed resin obtained by the method (b) again. That is, it cannot be recycled as a raw material for obtaining a foam sheet having a beautiful appearance and a high closed cell ratio.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a recyclable multilayer foam having excellent gas barrier properties, oil resistance, and solvent resistance, which is composed of a laminate of a polystyrene resin foam and an aromatic polyester resin. Furthermore, it is an object of the present invention to provide a foam excellent in thermoformability such as deep drawing such as cup shape and bowl shape.
[0004]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have not been able to solve the above problems even when using a laminated foam of a polystyrene resin foam and an aromatic polyester resin. This is because an aromatic polyester resin such as polyethylene terephthalate is a crystallized polymer, and when a mixed resin of polystyrene resin and an aromatic polyester resin such as polyethylene terephthalate that has been remelted and recycled is to be foamed again. Under the optimum foaming conditions for polystyrene, aromatic polyester resins such as polyethylene terephthalate become crystallized products, which deteriorate the appearance of the foam, or even if the appearance is good, the generation of crystallized products breaks when the bubbles expand during foaming. It has been found that this is due to the fact that a foam having a good cell structure cannot be obtained due to bubbles.
In addition, in the thermoformability of foams, especially sheet-like ones, thermoforming into containers of multilayer foams in which an aromatic polyester resin such as a film-like polyethylene terephthalate is bonded to one or both sides of a polystyrene resin foam Is difficult compared to that of a single layer of polystyrene resin foam because the thermoforming temperature of an aromatic polyester resin such as polyethylene terephthalate is higher than the thermoforming temperature of the polystyrene resin foam, Under the optimal thermoforming conditions for polystyrene resin foams, aromatic polyester resins such as polyethylene terephthalate are hard and difficult to stretch, so the resulting molded product will be wrinkled or an aromatic polyester resin layer such as polyethylene terephthalate. Aromatic polyester such as polyethylene terephthalate The ether-based resin to the optimum thermoforming conditions found that melting of the polystyrene resin foam, because the defoaming is likely to occur.
Thus, as a result of further research, the present inventors have completed the present invention.
[0005]
  That is, according to the present invention, in a laminate in which a film-like aromatic polyester resin is laminated on at least one surface of a foamed sheet or foamed plate made of a polystyrene resin via an adhesive layer, the aromatic polyester resin ResinWhen the constant temperature increase test was performed at a temperature increase rate of 10 ° C./min, satisfying the following conditions:A polyester-based resin-laminated polystyrene-based resin foam comprising an aromatic polyester-based resin having a flow start temperature at a load of 4.9 kN of 200 ° C. or lower is provided.
  Conditions: a polyester copolymer of a diol component unit composed of an ethylene glycol component unit and a cyclohexanedimethanol component unit and a dicarboxylic acid component unit composed of a terephthalic acid component unit,
  A polyester copolymer of a diol component unit comprising an ethylene glycol component unit, a dicarboxylic acid component unit comprising a terephthalic acid component unit and an isophthalic acid component unit,
  And a mixture of one or more selected from a polyester copolymer of a diol component unit comprising an ethylene glycol component unit, a neopentyl glycol component unit, and a dicarboxylic acid component unit comprising a terephthalic acid component unit
  Moreover, according to the present invention, on one side of the foam sheet or foam plate made of polystyrene resin,When the constant temperature rise test is performed at a temperature rise rate of 10 ° C / min, which satisfies the following conditions:A film-like aromatic polyester resin composed of an aromatic polyester resin having a flow starting temperature of 200 ° C. or less at a load of 4.9 kN is laminated via an adhesive layer, and the other surface of the foam sheet or foam plate A polyester-based resin-laminated polystyrene-based resin foam is provided in which a film-like polystyrene-based resin is laminated.
  Conditions: a polyester copolymer of a diol component unit composed of an ethylene glycol component unit and a cyclohexanedimethanol component unit and a dicarboxylic acid component unit composed of a terephthalic acid component unit,
  Polyester copolymer of diol component unit composed of ethylene glycol component unit, dicarboxylic acid component unit composed of terephthalic acid component unit and isophthalic acid component unit, and diol component unit composed of ethylene glycol component unit and neopentyl glycol component unit and terephthalic One or a mixture of two or more selected from polyester copolymers with dicarboxylic acid component units comprising acid component units
  Furthermore, according to the present invention,When a constant temperature increase test was conducted at a temperature increase rate of 10 ° C / min.An aromatic polyester resin having a flow starting temperature of 200 ° C. or less at a load of 4.9 kN includes a terephthalic acid component unit as a main carboxylic acid component unit, and an ethylene glycol component unit and a cyclohexanedimethanol component unit as main diol component units. The polyester-based resin-laminated polystyrene-based resin foam described above is characterized in that it is a polyester copolymer containing.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
  The polyester resin-laminated polystyrene resin foam of the present invention (hereinafter also simply referred to as Pe / PS foam) is a film-like aromatic polyester resin on at least one surface of a foam sheet or foam plate made of polystyrene resin. In the laminate laminated via the adhesive layer, the aromatic polyester resin is, When a constant temperature increase test was performed at a temperature increase rate of 10 ° C / min.Flow start temperature at 4.9kN load(Hereafter, it is also simply referred to as a flow start temperature at a load of 4.9 kN.)Is made of an aromatic polyester resin having a temperature of 200 ° C. or lower. The flow start temperature referred to in this specification is Shimadzu flow tester CFT-500A manufactured by Shimadzu Corporation. Die size diameter 1.0 mm × length 10.0 mm Load 4.9 kN, temperature rising rate 10 ° C. / Constant speed in minAscensionThis is the temperature at which piston displacement begins when a temperature test is performed.
[0007]
In the present invention, a polystyrene resin is used as the base resin of the foam, and the laminated resin is made of an aromatic polyester resin having a flow start temperature of 200 ° C. or less at a load of 4.9 kN. When an aromatic polyester-based resin having a flow initiation temperature at a load of 4.9 kN exceeding 200 ° C. is used on one or both surfaces of the polystyrene-based resin foam, the aromatic such as polyethylene terephthalate is compared with the thermoforming temperature of the foam. Due to the high thermoforming temperature of the polyester-based resin, the aromatic polyester-based resin is hard and difficult to stretch under the optimal thermoforming conditions for the foam. The resulting molded product is wrinkled or the aromatic polyester-based resin layer is torn. In particular, it is difficult to perform thermoforming with a drawing ratio of 0.4 or more. Also, under the optimum thermoforming conditions for an aromatic polyester-based resin layer having a flow start temperature of more than 200 ° C. at a load of 4.9 kN, such as polyethylene terephthalate, the appearance of surface irregularities of the molded body due to melting and defoaming of the foam Since the reduction tends to occur, thermoforming of the multilayer foam into a container becomes difficult as compared with a single-layer polystyrene resin foam.
In addition, when trying to re-foam a mixed resin of an aromatic polyester-based resin and a polystyrene-based resin having a flow start temperature exceeding 200 ° C. at a load of 4.9 kN that has been remelted and recycled, the foaming of the polystyrene-based resin is usually performed. Extrusion foaming must be performed at a temperature, and if extrusion foaming is performed at the foaming temperature, a crystallized product of an aromatic polyester resin is generated, and a beautiful sheet cannot be obtained.
[0008]
In order to further enhance the reliability of the excellent deep-drawability, the prevention of crystallization of the aromatic polyester-based resin when the recycle raw material obtained by remelting the Pe / PS foam of the present invention is extruded and foamed. The aromatic polyester resin preferably comprises a resin having a flow start temperature at a load of 4.9 kN of 190 ° C. or lower, more preferably 180 ° C. or lower. From the viewpoint of heat resistance, the lower limit is preferably 120 ° C.
[0009]
The aromatic polyester resin having a flow start temperature of 200 ° C. or less at a load of 4.9 kN laminated in the present invention is a method of polycondensation of a dicarboxylic acid component and a diol component, a polyester homopolymer and / or a polyester co-polymer. It is produced by a transesterification reaction of a coalescence.
The dicarboxylic acid component of the aromatic polyester resin used in the present invention will be described in detail. As the dicarboxylic acid component, dicarboxylic acid or an ester-forming derivative thereof can be used. Examples of the ester-forming derivative include ester derivatives such as dimethyl ester and diethyl ester, salts such as diammonium salt, and acid halides such as dichloride.
As the dicarboxylic acid component unit in the polymer, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, phthalic acid, 4,4′-diphenyldicarboxylic acid, 3,4′-diphenyldicarboxylic acid, 1,4- Component units derived from aromatic dicarboxylic acids such as naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid or ester-forming derivatives thereof, or oxalic acid, Component units derived from aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, dodecanedioic acid or ester-forming derivatives thereof, or 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, decalin dicarboxylic acid Acid, alicyclic dicarboxylic acid such as tetralin dicarboxylic acid or Include a constituent unit derived from ester-forming derivatives, these one or more are contained in the polymer.
[0010]
The diol component of the aromatic polyester resin used in the present invention will be described in detail. As the diol component, aliphatic and aromatic diols (including divalent phenols) can be used.
The diol component unit in the polymer is derived from an aliphatic diol such as ethylene glycol, cyclohexanedimethanol, propylene glycol, neopentyl glycol, trimethylene glycol, diethylene glycol, 1,4-butanediol, or an ester-forming derivative thereof. Component units, component units derived from alicyclic diols such as 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,6-cyclohexanediol or ester-forming derivatives thereof, or bisphenol A, etc. Mention may be made of component units derived from aromatic diols or ester-forming derivatives thereof.
[0011]
  In addition, the aromatic polyester-based resin may have its molecular ends sealed with component units derived from a monofunctional compound such as a small amount of benzoic acid, benzoylbenzoic acid, methoxypolyethylene glycol, and the like. Further, it may contain a small amount of component units derived from polyfunctional compounds such as pyromellitic acid, trimellitic acid, trimesic acid, glycerin, pentaerythritol and the like. The flow start temperature of the aromatic polyester resin can be adjusted by using two or more kinds of terephthalic acid and isophthalic acid as the dicarboxylic acid component and changing the molar ratio of these dicarboxylic acid component units, and ethylene glycol as the diol component. It can be adjusted by a method of changing the molar ratio of these diol component units by using two or more kinds such as cyclohexanedimethanol. As the aromatic polyester resin having a flow starting temperature of 200 ° C. or less at a load of 4.9 kN, an aromatic polyester aromatic polyester copolymer having a flow starting temperature of 200 ° C. or less at a load of 4.9 kN is preferable. Among the aboveWhat is used in the present invention, A polyester copolymer of a diol component consisting of ethylene glycol and cyclohexanedimethanol and a dicarboxylic acid component consisting of terephthalic acid, a polyester copolymer of a diol component consisting of ethylene glycol and a dicarboxylic acid component consisting of terephthalic acid and isophthalic acid, Polyester copolymer of diol component consisting of ethylene glycol and neopentyl glycol and dicarboxylic acid component consisting of terephthalic acidIs one of. Particularly preferred from the viewpoint of deep drawability is a polyester copolymer of a diol component consisting of 75 to 40 mol% ethylene glycol and 25 to 60 mol% cyclohexanedimethanol and a dicarboxylic acid component consisting of terephthalic acid. Etc. Further, in the present invention, a film-like aromatic polyester resin comprising a resin having a flow start temperature at a load of 4.9 kN and a temperature of 200 ° C. or less is within a range that does not impair the objects and effects of the present invention.The specificIt is a mixture of two or more aromatic polyester resins, polystyrene resins, polyolefin resins, high impact polystyrene, styrene elastomer resins, elastomers and rubbers in a proportion of approximately 20% by weight or less. May be.
[0012]
Furthermore, in order to improve the heat resistance of the film-like aromatic polyester resin, the fragrance having a glass transition temperature of 100 ° C. or higher with respect to the aromatic polyester resin having a flow starting temperature at a load of 4.9 kN of 200 ° C. or lower. A group polyester resin, a polyolefin resin having a melting point of 125 ° C. or higher, and an inorganic or organic filler can also be added.
[0013]
The thickness of the aromatic polyester resin is preferably from 0.01 to 0.5 mm, particularly preferably from 0.01 to 0.2 mm. If it is less than 0.01 mm, it is stretched and further thinned during thermoforming, so that tears and pinholes are likely to occur, and the solvent resistance of the multi-layer foam tends to decrease, making it difficult to obtain sufficient oil resistance. When it exceeds 0.5 mm, adhesion with a polystyrene resin foam becomes difficult, resulting in high cost. From the viewpoint of the recyclability of the multilayer foam, the amount of laminated aromatic polyester resin is 50% by weight or less, preferably 25% by weight or less, based on the multilayer foam.
In addition, the aromatic polyester-based resin to be laminated includes various additives as necessary, for example, an antioxidant, a heat stabilizer, an antistatic agent, a conductivity-imparting agent, an ultraviolet ray inhibitor, a colorant, a flame retardant, An inorganic filler or the like can be appropriately added.
In addition, it is necessary to consider from the aspect of recyclability, but in addition to the film-like aromatic polyester resin laminated on the polystyrene resin foam, the film-like polyolefin resin is further formed on the aromatic polyester resin. It can also be laminated on the foam as a multilayer sheet in combination with other functional materials such as polyamide-based resin, polyvinylidene chloride, saponified ethylene-vinyl acetate copolymer, and aluminum foil.
In the present invention, when a polyolefin resin is laminated on a film-like aromatic polyester-based resin, as the polyolefin resin, olefin homopolymers, copolymers (random copolymers, block copolymers, etc.) and Blends and the like are included. In the present invention, in particular, in terms of heat resistance, the Vicat softening point is 112 ° C. or higher, and the softening point is 120 ° C. or higher (the upper limit of the softening point is not particularly limited, but is about 160 ° C.). In particular, the use of high-density polyethylene or polypropylene resin is preferred.
Polypropylene resins include propylene homopolymers, copolymers, blends, and the like.
In the propylene copolymer, the copolymer component includes ethylene, butylene, and other α-olefin, and the α-olefin has 12 or less carbon atoms, preferably 8 or less. The content of ethylene, butylene and other α-olefins as the copolymer component is preferably 20% by weight or less for a block copolymer and 8% by weight or less for a random copolymer.
In the blend of polypropylene resin, the blending resin includes an ethylene homopolymer, a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms, and an α- having 4 to 6 carbon atoms. Examples include olefin homopolymers.
In a preferred embodiment of the present invention, as the polyolefin resin forming the polyolefin resin layer, (i) a polypropylene resin having a melting point of 155 ° C. or lower (hereinafter also referred to as a low melting point polypropylene resin) and a polyethylene resin having a melting point of 130 ° C. or higher (hereinafter referred to as a high resin) A mixture of (ii) a polypropylene resin having a melting point of 155 ° C. (hereinafter also referred to as a high melting point polypropylene resin) and (iii) a polyethylene resin having a melting point of 130 ° C. or higher. It is done. In this case, “main component” means that the resin or mixed resin of (i) to (iii) occupies about 80% by weight or more of the polyolefin resin layer, and does not impair the object / effect of the present invention. For example, it means that other polymers such as polystyrene resin, nylon resin, polyester resin and rubber may be further included in the resins or mixed resins of (i) to (iii).
In the present invention, the polyolefin resin layer has a thickness of 0.01 to 0.07 mm, preferably 0.015 to 0.06 mm.
If it is less than 0.01 mm, the heat resistance of the Pe / PS foam may not be improved. Moreover, when it exceeds 0.07 mm, there exists a possibility that the heating range at the time of thermoforming may become narrow.
[0014]
The polystyrene resin used in the present invention includes styrene homopolymers and copolymers, and the styrene monomer units contained in the polymer are at least 25% by weight, preferably 50% by weight or more. A preferred polystyrene resin used in the present invention is a resin containing at least 25% by weight of a structural unit represented by the following general formula (1) in the resin.
[Chemical 1]

In the general formula (1), R represents a hydrogen atom or a methyl group, Z represents a halogen atom or a methyl group, and p is 0 or an integer of 1 to 3.
Examples of the polystyrene resin include polystyrene, rubber-modified polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, and styrene-methyl methacrylate. Copolymer, styrene-ethyl methacrylate copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-maleic anhydride copolymer, polystyrene-polyphenylene ether copolymer, polystyrene and Examples thereof include a mixture with polyphenylene ether. A blend of these resins with a styrene-conjugated diene block copolymer or a hydrogenated product thereof for the purpose of improving brittleness can also be used. In addition, since the heat resistance of the foam of this invention can be improved by using the polystyrene-type resin whose Vicat softening point is 110 degreeC or more, the use is preferable. In the present specification, the Vicat softening point of the resin refers to a value obtained by JIS K7206 (test load is A method, liquid heating method and temperature rise rate is 50 ° C./hour).
[0015]
190 ° C shear rate of the above polystyrene resin 100 sec^-1The melt viscosity in is preferably 200 Pa · S or more and less than 10,000 Pa · S. When the melt viscosity is less than 200 Pa · S, the molten resin extruded from the die at the time of molding the foam drips, making molding difficult. On the other hand, when the viscosity is 10,000 Pa · S or higher, the viscosity is too high, the extrusion pressure increases, and extrusion foaming is difficult, making it difficult to form a good foam. In this specification, the shear rate is 100 sec.^-1The melt viscosity of the resin under the above conditions is a value obtained with Leobis 2100 manufactured by Thiast Co., Ltd. under the condition of an orifice having an orifice diameter of 1.0 mm and an orifice length of 10 mm and a resin temperature of 190 ° C.
[0016]
The base resin of the foam of the present invention is mainly composed of the above-mentioned polystyrene resin, and other components include fluidity modifiers such as paraffin and polycaprolactone, nucleating agents such as talc, baking soda, and citric acid. Add appropriate amounts of various additives such as additives, antioxidants, heat stabilizers, antistatic agents, conductivity enhancers, UV inhibitors, colorants, flame retardants, inorganic fillers, rubbers, elastomers, etc. be able to.
In addition, a thermoplastic resin such as a polyethylene resin, a polypropylene resin, and an acrylic resin can be contained in the base resin at a ratio of approximately 45% by weight or less as long as the objects and effects of the present invention are not impaired. The amount is particularly preferably 20% by weight or less, preferably 10% by weight or less in the base resin. When the amount is too large, the foam may be out of gas quickly, and the foam may shrink after extrusion foaming, or the bubbles may melt and break when the foam is thermoformed.
The amount of the fluidity modifier contained in the base resin is particularly preferably 2 to 30% by weight, and preferably 5 to 20% by weight in the base resin.
[0017]
The polystyrene-based resin foam in the present invention is preferably obtained by melting the base resin under high temperature and high pressure conditions, mixing the melt with a foaming agent, and extrusion-foaming it into a low pressure zone.
The base resin is mainly composed of a polystyrene-based resin, but when mixing other thermoplastic resins, etc., the polystyrene-based resin and other thermoplastic resins in advance so as to have a specific weight ratio. After dry blending, kneading with a kneader, etc., even if it is supplied to an extruder and subjected to extrusion foaming, each resin etc. is supplied to the extruder and extruded to have a specific weight ratio by a screw feeder etc. The polystyrene resin foam of the present invention can also be obtained by carrying out extrusion foaming by kneading in the machine.
[0018]
Examples of the blowing agent include an inert gas, a saturated aliphatic hydrocarbon, a saturated alicyclic hydrocarbon, an aromatic hydrocarbon, a halogenated hydrocarbon, an ether, a ketone, and the like. Is used.
Specific examples of the blowing agent include carbon dioxide, nitrogen, water, propane, normal butane, isobutane, normal pentane, isopentane, neopentane, normal hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, methylcyclopropane, cyclobutane, cyclopentane, 1,1-dimethylcyclopropane, methylcyclopentane, ethylcyclopentane, 1,1,2-trimethylcyclopropane, trichlorofluoromethane, dichlorodifluoromethane 1,1-dichloro-1,1,1,2-tetrafluoroethane, 1,1-difluoro-1-chloroethane, 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane, 1,1 , 1,2,2-Pentafluoroethane, Methylchloro , Ethyl chloride, methylene chloride, ethylene chloride, dimethyl ether, 2-ethoxyethanol, acetone, ethyl methyl ketone, in acetylacetone, a combination of more of these alone or two can be cited.
Furthermore, examples of the decomposable foaming agent include azodicarbonamide, dinitrosopentamethylenetetramine, azobisisobutyronitrile, sodium bicarbonate and the like. These decomposable foaming agents can be used alone or in combination as appropriate.
Although the usage-amount of a foaming agent is used suitably according to the density of the target foam, it can be selected in the range of 0.01-0.1 mol per 100g of base resin.
[0019]
When the base resin is melted and the melt is mixed with a foaming agent and extruded and foamed into a low pressure zone to obtain a foam, it is desirable to perform melt mixing and cooling with one or more extruders.
That is, extrusion foaming is generally performed by melting the resin, adding a foaming agent, and then cooling until the resin reaches a viscosity suitable for foaming. For this reason, in the kneading step of the resin and the foaming agent, it is desired to sufficiently knead the screw having a kneading function of the extruder by rotating at a high rotational speed. On the other hand, in the cooling process, in order to increase the cooling efficiency, it is desired to reduce the rotational speed of the screw in order to suppress the shearing heat generation as much as possible. Therefore, if melt mixing and cooling are performed with a single extruder, the number of rotations of the screw must be reduced in order to achieve sufficient cooling, and kneading of the mixed resin and mixing of the resin and the foaming agent is not possible. It may become sufficient, and the foaming state of the resin may deteriorate, or the discharge amount of the extruder may decrease, resulting in a problem that productivity decreases. The kind of extruder used for producing the thermoplastic resin foam of the present invention and the screw shape are not particularly limited. As the structure of the extruder, a structure in which a static mixer and a gear pump are attached between the extruder and the die is preferable for obtaining a foam having a good thickness, appearance and density.
[0020]
The density of the foam sheet or foam plate in the Pe / PS foam obtained by the above method is preferably 0.05 to 0.7 g / cm.^ThreeMore preferably 0.1 to 0.5 g / cm^ThreeIt is. Density 0.05g / cm^ThreeIf it is less than the above, the strength of the molded body may be insufficient, and there may be a case where a hole is formed in the molded body due to insufficient elongation when heat vacuum forming. On the other hand, 0.7 g / cm^ThreeIf it exceeds, there is a problem in terms of light weight and economy, but the heat insulation of the container is lowered, and if food is put in the container and heated, it is hot and can not be held by hand, and the heat insulation characteristic of foam is insufficient There is.
Further, the thickness of only the foam constituting the Pe / PS foam is preferably 0.5 to 7 mm, more preferably 1 to 5 mm. If the thickness is less than 0.5 mm, there is a possibility that it cannot be practically used in terms of strength and heat insulation. When the thickness exceeds 7 mm, uneven heating inside and outside the foam tends to occur during thermoforming, and precise temperature control is required. In particular, those for thermoforming are preferably 0.7 to 5 mm.
The basis weight of the Pe / PS foam of the present invention is 250 to 600 g / m.²The thickness of the film-like aromatic polyester resin is more preferably 0.01 to 0.2 mm. Basis weight is 250 g / m²If the ratio is less than 1, when trying to obtain a molded product having a particularly large drawing ratio (0.8 or more), the side surface of the molded product becomes thin and the strength tends to be insufficient. On the other hand, the basis weight is 600 g / m.²Exceeding it is too heavy as a general container, which increases costs.
[0021]
The open cell ratio of the foam constituting the Pe / PS foam of the present invention is 50% or less, preferably 30% or less. When the open cell ratio exceeds 50%, the secondary foaming property of the foam deteriorates during thermoforming and the like, so that the mold reproducibility of the foam deteriorates and the thickness and thickness of the molded product are reduced. There is a decline. Further, the strength of the obtained molded body is weak at the same density.
The open cell ratio of the foam is the open cell ratio of the foam excluding the laminated film-like resin such as the film-like aromatic polyester resin of Pe / PS foam. ASTM D2856, Procedure C The actual volume of the foam (the sum of the volume of the closed cell portion and the volume of the resin portion) Vx (cm^Three) And calculated by the following formula.
[Expression 1]

However, Va: apparent volume of the foam (cm) obtained from the outer dimensions of the test piece^Three)
W: Weight of foam in test specimen (g)
ρ: Density of foam base resin (g / cm) in the test piece^Three)
Moreover, the value calculated from the density of the foam mentioned later and the apparent volume of the foam is adopted as the weight of the foam.
[0022]
In this specification, the measurement of the density of a foam is performed by the method shown below. The thickness and basis weight of the aforementioned Pe / PS foam were measured in advance, and a cross section of the Pe / PS foam in the width direction perpendicular to the extrusion direction of the Pe / PS foam was photographed at 10 intervals at a regular interval with a microscope. The average value of the thickness of the resin layer and the thickness of the adhesive layer measured from the photograph taken is calculated. The value obtained by subtracting the thickness of each layer from the thickness of the Pe / PS foam was taken as the thickness of the foam. Next, the basis weight of the resin layer and the adhesive layer is calculated by multiplying the thickness of the resin layer and the thickness of the adhesive layer by the resin density constituting each layer and converting the unit. A value obtained by subtracting the basis weight of the resin layer and the adhesive layer from the basis weight of the Pe / PS foam is defined as the basis weight of the foam. A value obtained by dividing the basis weight of the foam by the thickness of the foam is converted into a unit and adopted as the density of the foam.
[0023]
In the Pe / PS foam of the present invention, a film-like aromatic polyester resin is laminated on one side of a polystyrene resin foam via an adhesive layer, and a film-like polystyrene resin is laminated on the other side. be able to. By laminating this polystyrene resin, the thermoformability of the multilayer foam can be improved, and the printability on the surface is improved. The polystyrene resin to be laminated is not particularly limited, but rubber-modified polystyrene such as high impact polystyrene having high impact resistance, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, etc. Of these, styrene-conjugated diene block copolymers are preferred. Moreover, what mixed these with the polystyrene resin as needed, and what added rubber | gum and an elastomer suitably to the polystyrene resin are also suitable. The thickness of the film-like polystyrene resin is preferably 0.05 to 0.5 mm, particularly 0.08 to 0.2 mm, more preferably 0.08 to 0.2 mm, and the film-like polyester laminated on the other side. The thickness is preferably 6 times or less and 1 time or more of the thickness of the resin. If the thickness is less than 0.05 mm, it is difficult to obtain a sufficient moldability improvement effect. If the thickness exceeds 0.5 mm, the cost becomes high. If the thickness exceeds 6 times, thermoforming is performed. Occasionally, it may be necessary to increase the accuracy of heating balance control between the polyester resin layer surface and the polystyrene resin layer surface. In addition, the density of the film-like polystyrene resin is 0.3 g / cm in consideration of the case where it is slightly foamed or an inorganic substance is added.^ThreeThe above is preferable. Density is 0.3g / cm^ThreeIf it is less than this, the printability on this surface may be lowered.
[0024]
Next, an adhesive layer (hereinafter also simply referred to as an adhesive layer (1)) for adhering a film-like aromatic polyester resin and a foam made of polystyrene resin will be described. Examples of the adhesive layer (1) include a polyethylene polymer, a polypropylene polymer, a polyolefin polymer such as an ethylene-vinyl acetate copolymer, and a dicarboxylic acid component unit in the polymer constituting the aromatic polyester resin. And an aromatic or aliphatic polyester polymer comprising a diol component unit in the polymer, other mixtures of aromatic polyester resin and polystyrene resin, a mixture of polyolefin polymer and polystyrene resin, and the polyester Addition that acts as a compatibilizing component or elastic component as necessary, with a mixture of a polyester polymer consisting of a dicarboxylic acid component unit and a diol component unit similar to those of a polymer and a polystyrene resin as the main component Foam and aromatic polyester resin with added additives Adhesive strength can be mentioned those more adhesive 490 mN / cm is expressed. The main component of the adhesive layer (1) means a resin component that contributes to adhesion, and is contained in an amount of 25% by weight or more, preferably 30% by weight or more based on the total weight of the adhesive layer. It is. Examples of the additive that acts as the compatibilizing component and the elastic component include recyclability and cost, such as rubber-modified polystyrene such as high impact polystyrene, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer. It is preferable to employ a styrene-based copolymer such as a styrene-conjugated diene block copolymer such as a polymer or a hydrogenated product thereof.
[0025]
As described above, the adhesive strength between the foam and the aromatic polyester resin is preferably 490 mN / cm or more, more preferably 960 mN / cm or more, and further preferably 2940 mN / cm or more. If the adhesive strength is less than 490 mN / cm, when trying to obtain a molded product having a large drawing ratio (0.4 or more), there is a high possibility that the modified polyester resin layer or the adhesive layer will be peeled off during molding.
In the present specification, the adhesive strength of 490 mN / cm or more naturally includes those in which the foam and the aromatic polyester resin do not peel.
In the present invention, the adhesive strength between the foam and the aromatic polyester resin is measured by a 90 ° peel test with a peel rate of 300 mm / min in accordance with JIS Z 0237 by cutting a test piece having a width of 25 mm. A value calculated by dividing the obtained peel strength (mN / 25 mm) by 2.5 is defined as an adhesive strength (mN / cm).
[0026]
From the viewpoint of sufficient adhesion in the main component of the adhesive layer (1), a polyolefin polymer or a mixture of a polyolefin polymer and a polystyrene resin, a polyester resin and a polystyrene resin having a melting point of 200 ° C. or less. And a polyester-based polymer, or a mixture of a polyester-based polymer and a polystyrene-based resin as a main component. Among them, among the polyolefin-based polymers, an ethylene-melting point of 105 ° C. or higher, more preferably 110 ° C. or higher. A vinyl acetate copolymer or a mixture of the ethylene-vinyl acetate copolymer and a polystyrene-based resin such as high impact polystyrene is particularly preferable in terms of cost, adhesiveness, and heat resistance. When a polystyrene resin is mixed with a polyolefin polymer or a polyester polymer, an arbitrary mixing ratio can be selected in a range satisfying an adhesive strength of 490 mN / cm or more. It is desirable to blend 50% by weight or more of the resin. Further, among the ethylene-vinyl acetate copolymer and the polyester-based polymer, it is possible to select a non-crystalline or high heat-resistant Pe / PS foam having a melting point of 200 ° C. or lower and 105 ° C. or higher. It is desirable in that it is obtained.
The melting point in this specification is determined from the melting peak of the DSC curve obtained by heat flux differential scanning calorimetry performed according to JIS K7121. Details are as follows. About 5 mg of a film with a thickness of 0.5 mm or less is used as a test piece, and the test piece is packed in a differential scanning calorimeter container to a temperature about 30 ° C. higher than the temperature at the end of the melting peak at room temperature to a heating rate of 10 ° C./min. DSC curve obtained when the temperature is immediately lowered to 40 ° C. at a cooling rate of 10 ° C./min, and then immediately heated to a temperature about 30 ° C. higher than the temperature at the end of the melting peak at a heating rate of 10 ° C./min. The melting point is the apex temperature of the melting peak (1) (the melting peak area is larger when two or more melting peaks are present). In this specification, a Shimadzu heat flux differential scanning calorimeter DSC-50 manufactured by Shimadzu Corporation is used as a differential scanning calorimeter, and the above measurement is performed with a nitrogen gas inflow rate of 20 ml per minute. The melting point was adopted.
[0027]
The polyethylene, polypropylene, ethylene-vinyl acetate, polyolefin, and polyester polymers exemplified as the main component of the adhesive layer (1) may be thermoplastic elastomers, resins, or rubbers. In addition, the aforementioned adhesive strength of 490 mN / cm²The polymer expressing the above is, for example, rosin, hydrogenated rosin, polymerized rosin, polymerized rosin, rosin ester and other rosin resins, terpene resin, hydrogenated terpene resin, petroleum resin, hydrogenated petroleum resin, polystyrene, etc. It is possible to obtain a modified polymer by adding 5 to 50% by weight of the tackifier and further adding 40% by weight or less of wax as necessary.
In addition, when a mixture of an aromatic polyester-based resin and a polystyrene-based resin or a mixture of a polyester-based resin having a melting point of 200 ° C. or less and a polystyrene-based resin is used for the adhesive layer (1), a mixing ratio showing high adhesive strength. Can be selected by the PI value (phase structure index) representing the mixed state of the two. The PI value is defined by the following formula.
[Expression 2]
PI value = (η (ps) · φ (x) / η (x) · φ (ps)) (2)
In the above formula, φ (ps) is the volume fraction of the polystyrene resin phase in the adhesive layer (1), η (ps) is 190 ° C., and the shear rate is 100 sec.^-1In the adhesive layer (1) is the volume fraction of the aromatic polyester resin phase or polyester polymer phase, η (x) is 190 ° C., and the shear rate is 100 sec.^-1Is the melt viscosity of the resin.
The thickness of the adhesive layer (1) is preferably 0.01 to 0.1 mm, particularly preferably 0.01 to 0.08 mm. If it is less than 0.01 mm, sufficient adhesive strength is difficult to obtain, and if it exceeds 0.1 mm, the cost becomes high.
In the present invention, the preferred PI value range is 0.7 to 1.3, more preferably 0.8 to 1.2. If the range of the PI value is out of the above range, the adhesive strength may decrease.
In the present invention, the Pe / PS foam is a polyolefin resin layer, an adhesive layer (2), an aromatic polyester resin layer, an adhesive layer (1), a polystyrene resin foam sheet, an adhesive layer (3), or a polyolefin resin layer. Examples of the adhesive layer (1) include, in addition to the above-described resins, those mainly composed of a mixture of a polyolefin resin, an aromatic polyester resin, and a polystyrene resin. From the viewpoint of recyclability, it is preferable that the main component is a mixture of polyolefin resin, aromatic polyester resin and polystyrene resin. In this case, the weight mixing ratio of the mixed resin is preferably 10 to 25% by weight of the polyolefin resin, 10 to 25% by weight of the aromatic polyester resin, and 80 to 50% by weight of the polystyrene resin from the viewpoint of adhesiveness of each layer. .
[0028]
In the present invention, when a film-like polyolefin resin is laminated and bonded onto a film-like aromatic polyester resin, an adhesive layer is not necessarily required. In that case, for example, the film-like aromatic polyester-based resin contains the same kind of polyolefin resin that is the same as or heat-sealable with the film-like polyolefin resin, or the film-like polyolefin resin contains the film-like aromatic polyester. And the like, or the same kind of aromatic polyester resin that can be heat-sealed. Moreover, in order to improve adhesiveness, it is preferable to pass through an adhesive layer.
[0029]
As an adhesive layer when laminating a polyolefin resin on an aromatic polyester (hereinafter simply referred to as an adhesive layer (2)), in addition to a commonly used adhesive, its main component is an aromatic polyester type in terms of recyclability. What has a mixture of resin and polyolefin resin as a main component is used preferably. The weight ratio of the aromatic polyester resin to the polyolefin resin is 5:95 to 70:30, and is further 10:90 to 60:40, particularly 15:85 to 45:55 from the viewpoint of improving the heat resistance of the adhesive layer. preferable. The total amount of the aromatic polyester resin and the polyolefin resin is 50% by weight or more based on the total weight of the adhesive layer (2). The polyolefin resin used for the adhesive layer (2) is preferably the same resin as the polyolefin resin used for the polyolefin resin layer laminated on the adhesive layer (2) or the same kind of polyolefin resin that can be heat-sealed. It is done.
Among the above, from the viewpoint of heat resistance, a polyolefin resin similar to the illustration of the polyolefin resin laminated and adhered onto the above-described film-like aromatic polyester resin is preferable.
[0030]
Adhesion although the adhesive strength between the adhesive layer (2) and the aromatic polyester resin layer is satisfactory when the amount of the aromatic polyester resin in the mixed resin of the adhesive layer (2) exceeds 5:95. There is a possibility that the adhesive strength between the layer and the polyolefin resin layer becomes insufficient. On the other hand, when the amount of the aromatic polyester resin becomes lower than 70:30, the adhesive strength between the adhesive layer (2) and the polyolefin resin layer can be satisfied, but the aromatic polyester resin layer and the adhesive layer (2). There is a risk that the adhesive strength between the two will be insufficient.
The thickness of the adhesive layer (2) is within a range of 0.015 to 0.2 mm, and the adhesive force tends to increase as the thickness increases, and is preferably 0.02 to 0.15 mm. The thickness of the adhesive layer (2) is 3 to 50%, preferably 5 to 40% of the thickness of the aromatic polyester resin layer. When the thickness of the adhesive layer (2) is smaller than 3%, the adhesiveness is insufficient. On the other hand, when the thickness exceeds 50%, the cost increases.
The aromatic polyester-based resin described above can be used as the aromatic polyester-based resin of the adhesive layer (2).
[0031]
In addition, when laminating and adhering a polyolefin resin on the above-described film-like aromatic polyester resin, foaming made of a film-like aromatic polyester-based resin and a polystyrene-based resin is used when adhering via the adhesive layer (2). Similar to the PI value (phase structure index) described in the adhesive layer for adhering the sheet, it can be selected between the aromatic polyester polymer and the polyolefin resin by the PI value.
In the present invention, the preferred PI value range is 0.7 to 1.3, more preferably 0.8 to 1.2. When the range of the PI value is out of the above range, the adhesive strength may decrease. In the present invention, in the case where at least one side is a polyolefin resin layer, it is preferable to use a mixed resin obtained by melting Pe / PS foam as the adhesive layer from the viewpoint of recyclability.
The mixed resin is a main component of the resin constituting the adhesive layer, and is contained in an amount of 25% by weight or more, preferably 30% by weight or more based on the total weight of the adhesive layer.
Furthermore, the additive which acts as a compatibilizing component and an elastic component described above can be added.
[0032]
In the Pe / PS foam of the present invention, a film-like polyolefin resin is laminated on a film-like aromatic polyester-based resin, and an adhesive layer (hereinafter also simply referred to as an adhesive layer (3)) is formed on the other side. A film-like polyolefin resin can be laminated via The Pe / PS foam in which the polyolefin resin is laminated on both sides is preferable in terms of improving heat resistance and folding resistance.
The base resin and the thickness of the film-like polyolefin resin to be laminated are the same as those of the film-like polyolefin resin laminated and adhered on the above-described film-like aromatic polyester resin.
At that time, examples of the adhesive layer (3) include those mainly composed of a mixture of a polystyrene resin and a polyolefin resin, and those mainly composed of a mixture of a polyolefin resin, an aromatic polyester resin and a polystyrene resin. . Among the above, those having as a main component a mixture of polyolefin resin, aromatic polyester resin and polystyrene resin are preferable from the viewpoint of recyclability.
In this case, the weight mixing ratio of the mixed resin is preferably 10 to 25% by weight of the polyolefin resin, 10 to 25% by weight of the aromatic polyester resin, and 80 to 50% by weight of the polystyrene resin from the viewpoint of adhesiveness of each layer. .
Furthermore, additives that act as compatibilizing components and elastic components are added to them as necessary, and an adhesive strength of 490 mN / cm or more between the foam made of polystyrene resin and the polyolefin resin is expressed. Can be mentioned. The main component of the adhesive layer (3) is that it is contained in an amount of 25% by weight or more, preferably 30% by weight or more based on the total weight of the adhesive layer (3).
[0033]
In the Pe / PS foam in which the film-like aromatic polyester resin layer, the adhesive layer, and the polystyrene resin foam of the present invention are sequentially laminated, the adhesive layer may be a multilayer. For example, by having a multilayer adhesive layer having a polystyrene resin layer on the polystyrene resin foam side, the resin temperature on the foam side during extrusion can be lowered, thereby reducing the open cell ratio of the foam layer. Can do. Furthermore, if this multi-layer adhesive layer is used as a container with a film-like aromatic polyester resin in the foam of Pe / PS as the inner surface side, it will improve strength against cracks, forks, etc. Can be made.
The polystyrene resin layer is not particularly limited, but rubber-modified polystyrene such as high impact polystyrene having high impact resistance, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, etc. Styrene-conjugated diene block copolymers are preferred. Moreover, what mixed these with the polystyrene resin as needed, and what added rubber | gum and an elastomer suitably to the polystyrene resin are also suitable.
Furthermore, a polyolefin resin can be added to the above polystyrene-based resin in order to adjust the resin temperature low during extrusion. The amount added is preferably 40% by weight or less, particularly preferably 30 to 5% by weight, based on the polystyrene resin layer. When the addition amount exceeds 40% by weight, the adhesiveness with the polystyrene resin foam decreases.
At that time, the thickness of the polystyrene resin layer is preferably 0.05 to 0.2 mm. When the thickness is less than 0.05 mm, it is difficult to obtain the above-described effect, and when the thickness exceeds 0.2 mm, the cost becomes high.
[0034]
The foam of Pe / PS of the present invention can be produced by the following method.
As a typical method when a film-like aromatic polyester-based resin and an adhesive layer (1) a foam made of a polystyrene-based resin are sequentially laminated, for example, (a) a single-layer polystyrene-based resin foaming by an extruder After that, a sheet obtained by laminating the aromatic polyester resin and the adhesive layer (1) by a co-extrusion method from another extruder on the production line or in another line is heated on this foam. (B) A method in which an adhesive layer (1) is provided on at least one surface of a foam by a coextrusion method using an extruder, and then the foam is subjected to a production line or another A method of laminating and adhering an aromatic polyester-based resin from another extruder in a line, (c) An adhesive layer (1) is provided on at least one side of the foam by a coextrusion method using an extruder And then, on the production line or in another line, the method of laminating and bonding the aromatic polyester resin film through a heat roll or the like, (d) the foam, the adhesive layer (1) and the aromatic polyester resin (E) A single-layer foam is produced by an extruder and then extruded from another extruder on the production line or on a separate line. A method of laminating and adhering an aromatic polyester resin extruded from another extruder through the adhesive layer (1), and (f) producing a single layer foam by the extruder, In contrast, a method of laminating and bonding an aromatic polyester-based resin film via an adhesive layer (1) extruded from another extruder on a production line or another line, and (g) a single layer foam by an extruder Manufacture Thereafter, a method of laminating and bonding a laminate of the aromatic polyester resin and the adhesive layer (1) extruded by a co-extrusion method from another extruder on the production line or in another line to the foam. Etc.
When manufacturing by the method of (b), (c), (d), the resin temperature at the time of extruding the adhesive layer (1) is the resin temperature at the time of extruding the foam plus 20 ° C. or less, preferably the resin temperature plus 10 It is desirable that the temperature is not higher than ° C. When the resin temperature exceeds 20 ° C., the open cell ratio of the foam may increase. In addition, it cannot be overemphasized that the minimum of the resin temperature at the time of extrusion of an adhesive layer (1) is a temperature which can be melt-extruded. In addition, the melt viscosity of the aromatic polyester resin laminated on the foam is not particularly limited, but when considering the coextrusion method, the melt viscosity may be close to the polystyrene resin used for the foam. Desirably, preferably in the range of 1/4 or more and less than 4 times that of polystyrene resin. Of the above-mentioned (a) to (g) laminated bonding methods, the method (d) is preferable because the process is simple and the cost can be reduced as compared with other methods.
Furthermore, when laminating and adhering a polyolefin resin layer on an aromatic polyester-based resin layer, the polyolefin resin layer or the adhesive layer (2) and the polyolefin resin layer are bonded in the same manner as in the above (a) to (g). Furthermore, the method of laminating and bonding is mentioned.
Among them, the method using the co-extrusion method in the order in which it is intended is preferable because the process is simple and the cost can be reduced as compared with other methods.
[0035]
If necessary, a colorant can be added to the adhesive layer of the present invention in an amount of less than 20% by weight based on the adhesive layer.
Examples of the colorant used in the present invention include black, gray, brown, yellow, red, pink, green, and blue color pigments and dyes. Among these, a pigment is preferable from the viewpoint of heat resistance. Examples of the pigment include organic pigments and inorganic pigments. Examples of organic pigments include azo pigments and copper phthalocyanine pigments. Examples of the inorganic pigment include titanium white, chrome lead, cadmium pigment, dial, carbon black and the like.
Further, the colorant may be put into the extruder as it is, but the masterbatch method is preferable in consideration of handling, workability, and dispersibility when added to the resin. In that case, the addition amount of the colorant in the master batch is 1 to 70 parts by weight, preferably 30 to 60 parts by weight, with respect to 100 parts by weight of the base resin of the master batch.
In the present invention, the outermost layer of the Pe / PS foam may be colorless or the same or similar color as the adhesive layer. When the outermost layer is made colorless, it is preferable that the inner surface of the container that comes into contact with the food is colorless, since the colorant does not come into contact with the food. Further, when the outermost layer has the same or similar color as the adhesive layer (1) or the adhesive layer (3), the color of the adhesive layer can be supplemented.
For the purpose of improving heat resistance, for example, an aromatic polyester resin having a glass transition point of 100 ° C. or higher, a polyolefin resin having a melting point of 125 ° C. or higher, and an inorganic or organic filler are added to the adhesive layer of the present invention. be able to.
[0036]
The Pe / PS foam of the present invention can be reused as a raw material for the foam layer or / and an adhesive layer by remelting defective products, molded products, and post-molded dregs of the Pe / PS foam. In the case of a Pe / PS foam using a polyolefin resin, polyamide resin, polyvinylidene chloride resin, saponified ethylene vinyl acetate copolymer, etc. on the film-like aromatic polyester resin or on the adhesive layer, remelt When reusing as a raw material for the foam layer, depending on the content of the polyolefin, etc., the foam layer tends to be open, and a low-density foam layer may not be obtained. It is preferable to reuse.
The ratio of remelting the Pe / PS foam and reusing it as a raw material for the foam layer or the adhesive layer was 100% by weight of the total resin content of the foam layer when reusing it as a raw material for the foam layer. At this time, it is preferable from the viewpoint of foamability and recyclability that the mixed resin obtained by remelting the Pe / PS foam contains 5 to 40% by weight of the total resin amount of the foam layer. Moreover, when reusing as an adhesive layer, when the total resin amount of the adhesive layer is 100% by weight, the mixed resin obtained by remelting the Pe / PS foam should contain 5 to 75% by weight of the total resin amount of the adhesive layer. Is preferable from the viewpoint of adhesiveness and recyclability.
[0037]
The Pe / PS foam of the present invention is heat-softened by using a mold, and vacuum molding and / or pressure molding using a mold, and further, thermoforming such as matched mold molding and plug assist molding using the same. Etc., it can be molded mainly into trays, cups, bowls, lunch boxes and the like. In addition, when shape | molding a Pe / PS foam, it is preferable to shape | mold so that an aromatic polyester-type resin laminated surface may be located in an inner layer side at least inside molded objects, such as a container.
[0038]
【Example】
Next, the present invention will be described more specifically with reference to examples.
[0039]
Example 1
As the extruder, two extruders having a diameter of 65 mm and a diameter of 90 mm were connected to a tandem type, and a die having a cylindrical slit having a diameter of 84 mm and a gap interval of 0.5 mm was used. .
In an extruder with a diameter of 65 mm, 96.9 parts by weight of polystyrene resin A and 0.8 parts by weight of talc as an additive are introduced from the raw material inlet, and heated and kneaded in the extruder to obtain a resin mixture adjusted to about 200 ° C. 2.3 parts by weight of foaming agent A was press-fitted, then supplied to an extruder having a diameter of 90 mm, adjusted to a resin temperature of 165 ° C., and the resin was extruded from the die.
The extruded cylindrical foamed resin was taken along a cooled cylinder having a diameter of 200 mm and then cut open to obtain a single-layer foamed sheet (thickness 1.9 mm), which was wound up.
[0040]
The polystyrene resin A is HH32, manufactured by Idemitsu Petrochemical Co., Ltd., its melt viscosity is 2040 Pa · S, Vicat softening point is 101 ° C., and density is 1.05 g / cm.^ThreeIt is.
As the talc, high filler # 12 manufactured by Matsumura Sangyo Co., Ltd. was used.
As the blowing agent A, a butane mixture composed of 70% by weight of n-butane and 30% by weight of iso-butane was used.
[0041]
Next, the obtained foam sheet, a polyester resin B film prepared in advance of 0.05 mm (thickness) and a multilayer film consisting of 0.03 mm (thickness) of polymer K (modified ethylene-vinyl acetate copolymer); Was laminated through a hot roll heated to 180 ° C. with the polymer K as the foamed sheet side to obtain a multilayer foamed sheet.
As the polyester resin B, Easter PETG6763 manufactured by Eastman Chemical Japan Co., Ltd., the flow starting temperature at a load of 4.9 kN is 147 ° C., the melt viscosity is 5000 Pa · S, and the density is 1.26 g / cm.^ThreeAs the polymer K (modified ethylene-vinyl acetate copolymer), Mersen MX28, melt viscosity 270 Pa · S, density 0.94 g / cm^Three, Melting point 117 ° C., manufactured by Tosoh Corporation.
[0042]
Example 2
As the extruder, two extruders having a diameter of 65 mm and a diameter of 90 mm were connected to a tandem type, and a die having a cylindrical slit having a diameter of 84 mm and a gap interval of 0.5 mm was used. .
In an extruder with a diameter of 65 mm, 97.3 parts by weight of polystyrene resin D and 0.9 parts by weight of talc (trade name: High Filler # 12) are added from the raw material inlet and heated and kneaded in the extruder. 1.8 parts by weight of foaming agent A was press-fitted into the resin mixture adjusted to 200 ° C., then supplied to an extruder having a diameter of 90 mm, adjusted to a resin temperature of 165 ° C., and the resin was extruded from the die.
The extruded cylindrical foamed resin was taken along a cooled cylinder having a diameter of 200 mm, and then cut open to obtain a single-layer foamed sheet (thickness 1.5 mm), which was wound up.
The polystyrene resin D is HH30, manufactured by Idemitsu Petrochemical Co., Ltd., and has a melt viscosity of 1500 Pa · S, a Vicat softening point of 98 ° C., and a density of 1.05 g / cm.^ThreeIt is.
Next, polymer C (modified ethylene-vinyl acetate copolymer) 0 having a resin temperature of 230 ° C. from an extruder having a diameter of 65 mm, in which a T-die having a width of 700 mm was attached as the adhesive layer (1) to the obtained foam sheet. 0.03 mm (thickness) was extruded to obtain a multilayer foamed sheet obtained by laminating and bonding a 0.05 mm (thickness) film made of polyester resin B prepared in advance through the adhesive layer to the foamed sheet.
As the polymer C (modified ethylene-vinyl acetate copolymer), trade name of Hirodine Co., Ltd .: Hirodine 7560, melt viscosity 270 Pa · S · density 0.925 g / cm^ThreeA melting point of 100 ° C. was used.
[0043]
Example 3
As the extruder, two extruders having a diameter of 65 mm and a diameter of 90 mm were connected to a tandem type, and a die having a cylindrical slit having a diameter of 84 mm and a gap interval of 0.5 mm was used. .
In an extruder with a diameter of 65 mm, 96 parts by weight of polystyrene resin E and 0.6 part by weight of talc (trade name: High Filler # 12) are added from the raw material inlet and heated and kneaded in the extruder. Then, 3.4 parts by weight of the foaming agent A was press-fitted into the resin mixture adjusted to 1, and then supplied to an extruder having a diameter of 90 mm, the resin temperature was adjusted to 163 ° C., and the resin was extruded from the die.
The extruded cylindrical foamed resin was taken along a cooled cylinder having a diameter of 200 mm, and then cut open to obtain a single-layer foamed sheet (thickness 2.05 mm), which was wound up.
The polystyrene resin E is a product name G9001, manufactured by A & M Styrene Co., Ltd., its melt viscosity is 2680 Pa · S, Vicat softening point is 110 ° C. or higher, and density is 1.1 g / cm.^ThreeIt is.
Next, a polymer C (modified ethylene-vinyl acetate copolymer) having a resin temperature of 230 ° C. from an extruder having a diameter of 50 mm and a polyester-based resin B having a resin temperature of 270 ° C. from an extruder having a diameter of 50 mm have a width of 700 mm. After being fed to a T-die and joined together in a die to form a multilayer, extrusion lamination was performed from the T-die to obtain a multilayer sheet. The thickness of each layer of the multilayer sheet was 0.05 mm (thickness) of polyester resin B and 0.05 mm (thickness) of polymer C.
Next, this multilayer sheet was thermocompression bonded to the foamed sheet with the polymer C as the foamed sheet side to obtain a multilayer foamed sheet.
[0044]
Example 4
Two extruders having a diameter of 65 mm and a diameter of 90 mm were connected to a tandem type as an extruder for producing a foam sheet. Further, an extruder having a diameter of 40 mm was used for manufacturing the adhesive layer (1), and a die having a cylindrical slit having a diameter of 84 mm and a gap interval of 0.5 mm was used.
98.1 parts by weight of polystyrene-based resin A for foam sheet production and 1.2 parts by weight of talc (trade name: High Filler # 12) are charged from the raw material inlet of an extruder with a diameter of 65 mm, and heated and kneaded in the extruder. 0.7 parts by weight of the foaming agent A was press-fitted into the resin kneaded product adjusted to about 200 ° C., and then supplied to an extruder having a diameter of 90 mm to adjust the resin temperature to 168 ° C. On the other hand, the polymer C constituting the adhesive layer (1) laminated on the foam sheet is extruded at a resin temperature of 150 ° C. from an extruder having a diameter of 40 mm, and the polymer C is laminated on one side of the foam sheet. And then co-extruded with the foamable resin inside the die.
The extruded cylindrical foamed resin is taken along a cooled cylinder having a diameter of 200 mm, and then cut open to obtain a multilayer foamed sheet (single-layer foamed sheet thickness 0.86 mm, adhesive layer (1) thickness 0). .08 mm), and this was wound up.
A polyester resin B having a resin temperature of 270 ° C. was extruded from an extruder having a diameter of 65 mm and a T-die having a width of 700 mm was attached to the obtained multilayer foamed sheet, and extrusion-lamination was performed to obtain a film-like polyester resin B having a thickness of 0.1 mm. A multilayer foamed sheet laminated and adhered via the adhesive layer (1) was obtained.
[0045]
Example 5
Two extruders having a diameter of 65 mm and a diameter of 90 mm were connected to a tandem type as an extruder for producing a foam sheet. In this case, an extruder having a diameter of 50 mm is used as the extruder for the aromatic polyester-based resin layer, an extruder having a diameter of 40 mm is used for producing the adhesive layer (1), and the diameter is 84 mm and the gap interval is 0. The one having a 5 mm cylindrical slit was used.
98.6 parts by weight of polystyrene-based resin A for foam sheet production and 0.3 part by weight of hydrocerol CF40S (manufactured by Dainichi Seika Kogyo Co., Ltd.) as a foam regulator are introduced from the raw material inlet of an extruder with a diameter of 65 mm. Then, 1.1 parts by weight of the foaming agent A is press-fitted into the resin kneaded product adjusted to about 200 ° C. by heating and kneading in the extruder, and then supplied to an extruder having a diameter of 90 mm to obtain a resin at 167 ° Adjusted to temperature. On the other hand, the aromatic polyester resin B laminated on the foam sheet is extruded by adjusting the resin temperature to 215 ° C. from an extruder having a diameter of 50 mm, and the resin constituting the adhesive layer (1) is polystyrene resin F 60% by weight. And a polyester-based resin G 40% by weight of the mixture, and this is adjusted to a resin temperature of 150 ° C. from an extruder with a diameter of 40 mm and extruded, and each of them forms an adhesive layer (1) from one side of the foam sheet from the foam sheet side. It supplied so that what was laminated | stacked in order of resin and the aromatic polyester-type resin might be obtained, and it united with the foamable resin inside the die | dye, and coextruded.
The extruded cylindrical foamed resin was taken along a cooled cylinder having a diameter of 200 mm and then cut open to obtain a multilayer foamed sheet, which was wound up.
In this multilayer foam sheet, the thickness of the single-layer foam sheet is 1.4 mm, the thickness of the adhesive layer (1) is 0.04 mm, and the thickness of the film-like aromatic polyester resin is 0.05 mm. The obtained sheet was extruded with a polystyrene resin L having a resin temperature of 260 ° C. from an extruder with a diameter of 65 mm equipped with a T-die having a width of 700 mm, extruded and laminated, and a film-like polystyrene resin having a thickness of 0.15 mm on one side. Was laminated and bonded, and a multilayer foamed sheet in which a film-like aromatic polyester resin was laminated and bonded to the other side of the adhesive layer (1) was obtained.
The polystyrene resin F is a product name of Stylon H8601, manufactured by A & M Styrene Co., Ltd., having a melt viscosity of 980 Pa · S, a Vicat softening point of 96 ° C., and a density of 1.05 g / cm.^ThreeIt is.
The polyester resin G is a product name: Bionore # 1903, manufactured by Showa Polymer Co., Ltd., and has a melt viscosity of 620 Pa · S, a melting point of 114 ° C., and a density of 1.26 g / cm.^ThreeIt is.
The polystyrene-based resin L is a product name RQ301, manufactured by Denki Kagaku Kogyo Co., Ltd., its melt viscosity is 1650 Pa · S, Vicat softening point is 97 ° C., density is 1.05 g / cm.^ThreeIt is.
[0046]
Example 6
A multilayer foam sheet was obtained in the same manner as in Example 5 except that the adhesive layer (1) was a polymer H (modified polyolefin polymer).
The polymer H (modified polyolefin polymer) is a product name: Admer SF730, manufactured by Mitsui Chemicals, Ltd., its melt viscosity is 1280 Pa · S, Vicat softening point is 54 ° C., and melting point is 120 ° C. The density is 0.9g / cm^ThreeIt is.
[0047]
Example 7
A multilayer foam sheet was obtained in the same manner as in Example 5 except that the adhesive layer (1) was a mixture of 50% by weight of polymer H and 50% by weight of polystyrene resin F.
[0048]
Example 8
A multilayer foam sheet was obtained in the same manner as in Example 5 except that the adhesive layer (1) was a polymer J (modified polyester polymer).
The polymer J (modified polyester polymer) is a product name: Aron Melt PES-11, manufactured by Toa Gosei Co., Ltd., its melt viscosity is 150 Pa · S, Vicat softening point is 70 ° C., melting point is 110 ° C., density is 1.2 g / cm^ThreeIt is.
[0049]
Example 9
A multilayer foam sheet was obtained in the same manner as in Example 5 except that the adhesive layer (1) was changed to the polymer K.
[0050]
Example 10
A multi-layer foam colored red in the same manner as in Example 9 except that 6% by weight of SBF-T-4586 (iron oxide) manufactured by Resino Color Industries Co., Ltd. was added as red to the adhesive layer (1). A sheet was obtained.
[0051]
Example 11
A single-layer foam sheet (thickness 2.1 mm) was obtained in the same manner as in Example 1, and this was wound up.
Next, from the obtained foamed sheet, a polyester resin B film 0.02 mm (thickness) prepared in advance by an extruder having a T-die width of 700 mm, and a mixture of polystyrene resin A 60% by weight and polyester resin B 40% by weight. A multilayer film having a multilayer adhesive layer (1) composed of 0.02 mm (thickness) of the resin layer and 0.07 mm (thickness) of the resin layer composed of the polystyrene resin M is a polystyrene resin of the adhesive layer (1). A multilayer foamed sheet was obtained by heat laminating through a hot roll heated to 180 ° C. with the resin layer consisting of M as the foamed sheet side.
In addition, in polystyrene resin M, Nippon Polystyrene Co., Ltd. high impact polystyrene (HIPS) “H640N (density 1.05 g / cm^Three) ”Was used.
[0052]
Example 12
A multilayer foam sheet was obtained in the same manner as in Example 11, and this was wound up.
Next, a polystyrene resin M having a resin temperature of 260 ° C. is extruded from a T-die extruder to the obtained multilayer foamed sheet, and extrusion lamination is performed. The other surface on which the adhesive layer is laminated has a thickness of 0.15 mm. A multilayer foamed sheet in which a film-like polystyrene resin was laminated and adhered was obtained.
[0053]
Comparative Example 1
A multilayer foamed sheet was obtained in the same manner as in Example 1 except that the polyester resin P was used in place of the polyester resin B as the polyester resin. The polyester-based resin P is manufactured by Nippon Unipet Co., Ltd., RT543, load start temperature of 4.9 kN is 255 ° C., 190 ° C., and is not melted, so melt viscosity cannot be measured. Density 1.26 g / cm^ThreeIt is.
[0054]
Comparative Example 2
A polyester resin P was used instead of the polyester resin B as the polyester resin, and a multilayer foamed sheet was obtained in the same manner as in Example 6 except that the resin temperature was adjusted to 270 ° C. from an extruder with a diameter of 50 mm and extrusion was performed. .
[0055]
Next, while measuring the physical properties such as the thickness and adhesive strength of each foamed sheet obtained in the examples and comparative examples, the extrusion foamability was evaluated, and the oil resistance moldability and heat resistance were as follows. And evaluated. The results are shown in Tables 1 to 3.
[0056]
(Oil resistance)
0.025 ml of rice cooking seasoning oil (Fresh Roll White, manufactured by Rolling Co., Ltd.) was dropped into the central part of the 25 mm × 40 mm multilayer foam sheet (central part of the aromatic polyester-based resin laminate surface of the multilayer foam sheet). After extending uniformly, it was heated at 80 ° C. for 5 minutes, and the change in the foamed sheet before and after heating was examined.
Y: No change
×: There is erosion on the sheet surface
[0057]
(Formability)
The multilayer foam sheets obtained in the examples and comparative examples were formed with a single molding machine (PLAVAC-FE36HP manufactured by Sanwa Kogyo Co., Ltd.) with an opening shape having a diameter of 150 mm, a bottom diameter of 120 mm, and a depth of 60 mm or 30 mm. A frustum-shaped container molding die was attached (vacuum molding was performed such that the aromatic polyester resin laminated surface was inside the container). In this molding test, the 40 dial scales of the upper heater voltage regulator were all set to 30, and the 6 dial scales of the lower heater voltage regulator were all set to 40. The moldability (thermoformability) was evaluated based on the appearance of the obtained molded body.
A: Good mold reproducibility and appearance at a drawing ratio of 0.9
○: Good mold reproducibility and appearance at a drawing ratio of 0.4 (depth 60 mm),
When the aperture ratio is 0.9, mold reproducibility and / or appearance is poor.
Δ: Good mold reproducibility and appearance at a drawing ratio of 0.2 (depth 30 mm),
When the aperture ratio is 0.4, the mold reproducibility and / or appearance is poor.
×: Mold reproducibility and / or appearance is poor even with a drawing ratio of 0.2
For the drawing ratio of 0.9, a frustoconical container molding die having a diameter of 95 mm, a bottom diameter of 70 mm, and a depth of 105 mm was used.
[0058]
As a result of the test, all of the multilayer foam sheets of the examples had a low open cell ratio, and a deep-drawn molded article having good mold reproducibility was obtained in the heat vacuum forming. Moreover, the adhesive strength was also strong.
On the other hand, the multilayer foam sheet of the comparative example could not obtain a deep-drawn molded article with good mold reproducibility in heat vacuum forming. Moreover, the thing of the comparative example 2 was a thing with a high open cell ratio even if the multilayer foamed sheet was obtained. In addition, as shown in Comparative Examples 1 and 2, an aromatic polyester-based resin having a flow start temperature at a load of 4.9 kN exceeding 200 ° C. is an aromatic polyester-based resin laminated in a film shape on a foamed sheet via an adhesive layer. In the multilayer foamed sheet, the polyester part did not stretch sufficiently under the molding conditions of the polystyrene-based resin foamed sheet in heat vacuum molding, and wrinkles were generated on the surface of the molded body.
[0059]
(Heat-resistant)
Pour hot water boiled in a depth of 50 mm into a molded product having a drawing ratio of 0.4 obtained in the thermoforming test for 5 seconds, then leave it for 4 minutes without a lid, and then throw away the hot water, The appearance of was observed.
Y: No change
Δ: Peeling of polyester resin layer on sheet surface
[0060]
(Adhesive strength)
A test piece having a width of 25 mm was cut out of the obtained sheet from the obtained sheet, and a value (mN / 25 mm) measured by a 90 ° peel test under a peel speed of 300 mm / min in accordance with JIS Z0237 was 2.5. The lower value of the adhesive strength (mN / cm) between the polyester resin and the adhesive layer and between the adhesive layer and the foam was adopted.
[0061]
(Melting viscosity of each resin)
The melt viscosity of each resin is a shear rate of 100 sec.^-1Using a nozzle with a nozzle diameter (D) of 1.0 mm and L / D = 10 (L is the nozzle length: mm), the measurement was performed with a Leobis 2100 manufactured by Chiast Corp. at a resin temperature of 190 ° C.
(Thickness of multilayer foam sheet, polyester resin, etc.)
The thickness was measured from arbitrary 20 points in the thickness direction vertical cross section of the multilayer foamed sheet, and the average value was adopted. In addition, thickness measurement calculated | required each thickness by converting into magnification using a microscope picture.
(Basis weight of multilayer foam sheet)
A test piece having a thickness of 20 cm long × 20 cm wide × Pe / PS foamed sheet was cut out from the Pe / PS foam, the weight (g) of the test piece was measured, and the basis weight (g / m) was obtained by multiplying the value by 25.²) Was calculated.
(Density of multilayer foam sheet)
A test piece similar to the basis weight measurement of the multi-layer foamed sheet was prepared, the test piece weight (g) was measured, and the test piece volume (cm) determined by the length (cm) of the length 20 cm × width 20 cm × Pe / PS foam sheet.^Three) By dividing the test piece weight (g).
(Density of polystyrene resin foam sheet)
Basis weight of multilayer foam sheet (g / m²) To basis weight (g / m) of polyester resin, adhesive layer (1) and polystyrene resin.²) Basis weight (g / m) of only the foam sheet obtained by subtracting (calculated from each density and thickness)²) In terms of unit weight (g / cm²) And the basis weight (g / cm²) Was divided by the thickness (cm) of the foam sheet alone.
(Flow start temperature)
Using a Shimadzu flow tester CFT-500A manufactured by Shimadzu Corporation, a constant velocity isothermal test was performed at a die size diameter of 1.0 mm × length of 10.0 mm, a load of 4.9 kN, and a heating rate of 10 ° C./min. The temperature at which piston displacement began sometimes was measured.
[0062]
[Table 1]

[0063]
[Table 2]

[0064]
[Table 3]

[0065]
Example 13
A polyester resin layer is laminated on one surface of the polystyrene resin foam via the adhesive layer (1), and a polyolefin resin layer is laminated on the polyester resin layer via the adhesive layer (2). A multilayer foam having a structure in which a polyolefin resin layer was laminated on the other surface of the foam via an adhesive layer (3) was produced as follows.
[0066]
(Extruder)
As an extruder for producing a polystyrene-based resin foam, two extruders having a diameter of 90 mm and a diameter of 120 mm and a tandem type were used.
As an extruder for forming an aromatic polyester resin layer, an extruder having a diameter of 45 mm was used.
As the polyolefin resin layer forming extruder, an extruder having a diameter of 65 mm was used.
As the extruder for forming the adhesive layer (2), an extruder having a diameter of 65 mm was used.
As an extruder for forming the adhesive layer (1) and the adhesive layer (3), an extruder having a diameter of 65 mm was used.
A die having a cylindrical slit with a diameter of 135 mm and a gap interval of 0.3 mm was used as a die for joining the resin flows extruded from the respective extruders and extruding the resin into a cylindrical shape.
[0067]
(Manufacture of multilayer foam)
98.6 parts by weight of polystyrene-based resin A for foams and 1.3 parts by weight of talc (trade name: High Filler # 12) as a foam regulator are charged from the raw material inlet of an extruder with a diameter of 90 mm and heated in the extruder. While kneading, 1.0 part by weight of foaming agent A was press-fitted into the kneaded product adjusted to about 200 ° C., and then supplied to an extruder having a diameter of 120 mm to adjust the resin temperature to 165 ° C.
[0068]
In each of two extruders with a diameter of 65 mm, as the resin composition for forming the adhesive layer (1) and the adhesive layer (3), polyolefin resin R 13.7% by weight, aromatic polyester resin B 12.3% by weight, polystyrene A resin added with 49% by weight of resin A, 5 parts by weight of additive X and 20% by weight of polymer K was supplied and kneaded by heating to adjust the resin temperature to 170 ° C.
Aromatic polyester resin B was supplied to an extruder having a diameter of 45 mm, heated and kneaded, and the resin temperature was adjusted to 200 ° C.
A mixture of 70% by weight aromatic polyester resin B for forming the adhesive layer (2) and 30% by weight polyolefin resin R was supplied to an extruder having a diameter of 65 mm, heated and kneaded, and the resin temperature was adjusted to 170 ° C.
Polyolefin resin Q was supplied to an extruder having a diameter of 65 mm, heated and kneaded, and the resin temperature was adjusted to 185 ° C.
Resin in each of the above extruders is merged inside the die and coextruded from the slit of the die, and polyolefin resin layer, adhesive layer (2), aromatic polyester resin layer, adhesive layer (1), polystyrene resin foam The cylindrical foamed resin laminated in the order of the layer, the adhesive layer (3), and the polyolefin resin layer is taken along a cooled cylinder having a diameter of 335 mm, and then cut open to obtain a laminated foam. I took it.
Various physical properties of the obtained laminated foam are shown in Table 4.
[0069]
Example 14
Example 13 except that EPS-E-40518 manufactured by Polycol Kogyo Co., Ltd. was added as yellow to the adhesive layers (1), (2), and (3) at a ratio of 8% by weight to 92% by weight of the mixed resin. Similarly, a laminated foam was obtained.
[0070]
Example 15
As a resin constituting the polyolefin resin layer, a mixed resin of 80% by weight of polyolefin resin Q and 20% by weight of polyolefin resin V was used.
As the adhesive layer (2), polyolefin resin Q67.2% by weight, aromatic polyester-based resin B 28.8% by weight, and 4% by weight of ESH-K-44392 manufactured by Polycol Kogyo Co., Ltd. as black were used. .
Adhesive layers (1) and (3) were polyolefin resin Q 10.4% by weight, polyolefin resin V 2.6% by weight, aromatic polyester resin B 11.6% by weight, polystyrene resin A 46.4% by weight, additive X5 0.0% by weight and a black color obtained by adding 4.0% by weight of ESH-K-44392 manufactured by Polycol Kogyo Co., Ltd. and 20.0% of polymer K were used.
A polystyrene resin foam layer was obtained in the same manner as in Example 13 except that 99% by weight of polystyrene resin A and 1.0% by weight of ESH-K-44392 manufactured by Polycol Kogyo Co., Ltd. were added as black. .
[0071]
Example 16
Polyolefin resin T (high density polyethylene) was used as the resin constituting the polyolefin resin layer.
For the adhesive layer (2), 30% by weight of polyolefin resin T and 70% by weight of aromatic polyester resin B were used.
The adhesive layers (1) and (3) used were those added with polyolefin resin T (14 wt%), aromatic polyester resin B (7.1 wt%), polystyrene resin A (38.9 wt%), and polymer K (40 wt%).
The polystyrene-based resin foam layer was charged with 98% by weight of polystyrene-based resin A and 1.3% by weight of talc (trade name: High Filler # 12) as a foam regulator, and heated and kneaded in the extruder. The foaming agent A was pressed into the kneaded product adjusted to 0 ° C. by 0.7% by weight, and then supplied to an extruder having a diameter of 120 m to adjust the resin temperature to 165 ° C. The density of the polystyrene resin foam layer is 0.19 g / cm.^ThreeA laminated foam was obtained in the same manner as in Example 13 with a thickness of 0.74 mm.
[0072]
Example 17
Polyolefin resin S (high density polyethylene) was used as the resin constituting the polyolefin resin layer.
30% by weight of polyolefin resin S and 70% by weight of aromatic polyester resin B in the adhesive layer (2) were used.
Adhesive layers (1) and (3) were prepared by adding 14% by weight of polyolefin resin S, 7.1% by weight of aromatic polyester resin B, 38.9% by weight of polystyrene resin W, and 40% by weight of polymer K.
The polystyrene resin foam layer is filled with 98% by weight of polystyrene resin W and 1.3% by weight of talc (trade name: High Filler # 12) as an air conditioner, and is heated and kneaded in the extruder, and is about 200 ° C. The foamed material A was 0.7% by weight injected into the kneaded product adjusted to, then supplied to an extruder with a diameter of 120 mm, and the laminated foam was the same as in Example 16 except that the resin temperature was adjusted to 165 ° C. Got the body.
The polyolefin resin Q is “F8188” (propylene-ethylene random copolymer, melting point 145.7 ° C., density 0.9 g / cm) manufactured by Chisso Corporation.^ThreeThe melt viscosity is 630 Pa · S (190 ° C.) and the bigat softening point is 120 ° C. or higher.
The polyolefin resin R is “PM761A” (propylene-ethylene block copolymer, melting point 163.4 ° C., density 0.9 g / cm, manufactured by Nippon Polyolefin Co., Ltd.).^ThreeThe melt viscosity is 660 Pa · S (190 ° C.), and the bigat softening point is 130 ° C.
The polyolefin resin S is “310E” (high density polyethylene, melting point 136 ° C., density 0.965 g / cm, manufactured by Idemitsu Petrochemical Co., Ltd.^ThreeThe melt viscosity is 1650 Pa · S (190 ° C.) and the bigat point is 130 ° C.
The polyolefin resin T is “Nipolon Hard 4000” (high density polyethylene, melting point 135 ° C., density 0.964 g / cm, manufactured by Tosoh Corporation).^ThreeThe melt viscosity is 630 Pa · S (190 ° C.) and the bigat point is 130 ° C.
The above-mentioned polyolefin resin V is “210JZ” (high density polyethylene, melt viscosity 820 Pa · S, melting point 135.6 ° C., density 0.968 g / cm, manufactured by Idemitsu Petrochemical Co., Ltd.^ThreeVicat softening point 129 ° C)
The polystyrene resin W is “Toyo Styrol GP TF-2-311” (styrene-methacrylic acid copolymer, Bigat softening point 110 ° C. or higher, density 1.05 g / cm, manufactured by Toyo Styrene Co., Ltd.^Three).
The additive X is “Tuftec H1141” (hydrogenated styrene butadiene styrene elastomer, density 0.91 g / cm, manufactured by Asahi Kasei Corporation.^Three).
In order to confirm the adhesiveness of each adhesive layer in the Pe / PS foams obtained in Examples 11 to 17, all the materials were destroyed as a result of the same method as the adhesive strength described above. The oil resistance, moldability, and body heat resistance in Table 4 were evaluated in the same manner as in Tables 1-3. Moreover, the thickness of each layer of Table 4, the basic weight of the whole multilayer foamed sheet, and the density of the polystyrene-type resin foamed sheet were performed as described above.
[0073]
[Table 4]

[0074]
Example 18
Two extruders having a diameter of 65 mm and a diameter of 90 mm were connected to a tandem type as an extruder for producing a foam sheet. An extruder with a diameter of 50 mm was used as the extruder for the aromatic polyester resin layer, and an extruder with a diameter of 40 mm was used for the adhesive layer (1) between the aromatic polyester resin layer and the foamed sheet layer. On the other hand, an extruder with a diameter of 50 mm was used for the polyolefin resin layer laminated on the other side, and an extruder with a diameter of 40 mm was used for the adhesive layer (3) between the polyolefin resin layer and the foamed sheet layer. A die having a cylindrical slit having a diameter of 84 mm and a gap interval of 0.5 mm was used.
96 parts by weight of polystyrene resin E for foam sheet production and 0.6 parts by weight of talc (High Filler # 12 manufactured by Matsumura Sangyo Co., Ltd.) are added from the raw material inlet of an extruder with a diameter of 65 mm. And 2.1 parts by weight of blowing agent A were press-fitted into the resin mixture adjusted to about 200 ° C., and then supplied to an extruder having a diameter of 90 mm to adjust the resin temperature to 163 ° C. On the other hand, the aromatic polyester resin B laminated on the foam sheet is extruded from a 50 mm diameter extruder at a resin temperature of 170 ° C., and the aromatic polyester resin B is used as an adhesive layer (1) between the aromatic polyester resin layer and the foam sheet layer. A mixed resin of 50% by weight of polyester resin B and 50% by weight of polystyrene resin E is extruded at a resin temperature of 168 ° C. from an extruder with a diameter of 40 mm, and a polyolefin resin N laminated on the other side is extruded from an extruder with a diameter of 50 mm. Extruded at a resin temperature of 165 ° C., and mixed resin of 30% by weight of polyolefin resin N and 70% by weight of polystyrene resin E for the adhesive layer (3) of the polyolefin resin layer and the foamed sheet layer was 167 ° C. from an extruder with a diameter of 40 mm. Extrusion was performed at the resin temperature, and they were combined in the die and coextruded.
The extruded simple foamed resin was taken along a cooled cylinder having a diameter of 200 mm, and then cut to obtain a multilayer foamed sheet, which was wound up. The thickness of each layer of this sheet is 0.024 mm of the aromatic polyester resin layer, 0.035 mm of the adhesive layer (1), 1.56 mm of the foam layer, 0.039 mm of the adhesive layer (3), and 0.031 mm of the polyolefin resin M layer. there were.
The above-mentioned polyolefin resin N is 520 MB, high density polyethylene manufactured by Idemitsu Petrochemical Co., Ltd., its melt viscosity is 1900 Pa · S, density is 0.964 g / cm.^Three, Vicat softening point 130 ° C, Izod impact value (-20 ° C) 30KJ / m²It is.
It was 2156 mN / cm as a result of measuring the adhesive strength of a polyolefin resin layer and a polystyrene-type resin foam sheet with the method of the above-mentioned adhesive strength of the obtained multilayer foamed sheet.
[0075]
Example 19
The same equipment and materials as in Example 18 were used except that the polyolefin resin O was used for the adhesive layer (1) between the aromatic polyester resin layer and the foamed sheet layer. The thickness of each layer of this sheet is 0.024 mm of the aromatic polyester resin layer, 0.035 mm of the adhesive layer (1), 1.56 mm of the foam layer, 0.039 mm of the adhesive layer (3), and 0.031 mm of the polyolefin resin M layer. there were.
As the polyolefin-based resin O described above, ACRIFTH WH202 ethylene-methyl methacrylate copolymer manufactured by Sumitomo Chemical Co., Ltd. was used.
It was 2156 mN / cm as a result of measuring the adhesive strength of a polyolefin resin layer and a polystyrene-type resin foam sheet with the method of the above-mentioned adhesive strength of the obtained multilayer foamed sheet.
The low temperature impact resistance of Table 5 was evaluated as follows.
(Low temperature impact resistance)
The multilayer foamed sheet obtained in Example 18 was formed with a single-sided molding machine (PLAVAC-FE36HP manufactured by Sanwa Kogyo Co., Ltd.) with the polyolefin resin layer on the outside of the container, and the opening shape was 150 mm long, 120 mm wide, and 30 mm deep. The container (drawing ratio 0.19) was molded with a mold for vacuum forming. The container is filled with 150 g of water as a content, and sealed with a lid for the opening. Then, after maintaining at −35 ° C. for 2 hours, it was taken out to room temperature (temperature 23 ° C., humidity 55%) and dropped on a stainless steel board from a height of 100 cm within 2 seconds. The damage state of the container at this time was investigated.
○ No change or cracks in the container.
× The container has holes or cracks inside the container.
[0076]
[Table 5]

[0077]
【The invention's effect】
  Of the present invention, When a constant temperature increase test was performed at a temperature increase rate of 10 ° C / min.A laminate of a film-like aromatic polyester resin having a flow starting temperature of 200 ° C. or less at a load of 4.9 kN and a polystyrene resin foam is excellent in oil resistance, solvent resistance, aroma retention, gas barrier properties, and open cell The ratio is low, the appearance is good, and it is suitable for thermoforming (particularly deep drawing). Further, the heat sealability (top sealability when molded into a container with the film-like aromatic polyester resin inside) is particularly good. Furthermore, when the film-like polyolefin resin is laminated on the film-like aromatic polyester resin, the heat resistance is high. In addition, the aromatic polyester resin-laminated polystyrene resin foam of the present invention or a molded body thereof can be reused as a raw material for the foam layer or a raw material for the adhesive layer depending on the purpose. The raw material loss of the polystyrene resin foam is small.

Claims (8)

In a laminate in which a film-like aromatic polyester resin is laminated on at least one surface of a foamed sheet or foamed plate made of a polystyrene resin via an adhesive layer, the aromatic polyester resin satisfies the following conditions: Polyester-based resin-laminated polystyrene comprising an aromatic polyester-based resin having a flow start temperature at a load of 4.9 kN when a constant temperature increase test is performed at a temperature increase rate of 10 ° C./min. Resin foam.
Conditions: a polyester copolymer of a diol component unit composed of an ethylene glycol component unit and a cyclohexanedimethanol component unit and a dicarboxylic acid component unit composed of a terephthalic acid component unit,
A polyester copolymer of a diol component unit comprising an ethylene glycol component unit, a dicarboxylic acid component unit comprising a terephthalic acid component unit and an isophthalic acid component unit,
And a mixture of one or more selected from a polyester copolymer of a diol component unit comprising an ethylene glycol component unit, a neopentyl glycol component unit, and a dicarboxylic acid component unit comprising a terephthalic acid component unit On one side of a foamed sheet or foamed plate made of polystyrene resin, the flow start temperature at a load of 4.9 kN is 200 ° C. when a constant temperature rise test is performed at a rate of temperature rise of 10 ° C./min. A film-like aromatic polyester resin comprising the following aromatic polyester resins is laminated via an adhesive layer, and a film-like polystyrene resin is laminated on the other surface of the foam sheet or foam plate. A polyester resin laminated polystyrene resin foam characterized by the above.
Conditions: a polyester copolymer of a diol component unit composed of an ethylene glycol component unit and a cyclohexanedimethanol component unit and a dicarboxylic acid component unit composed of a terephthalic acid component unit,
A polyester copolymer of a diol component unit comprising an ethylene glycol component unit, a dicarboxylic acid component unit comprising a terephthalic acid component unit and an isophthalic acid component unit,
And a mixture of one or more selected from a polyester copolymer of a diol component unit comprising an ethylene glycol component unit, a neopentyl glycol component unit, and a dicarboxylic acid component unit comprising a terephthalic acid component unit An aromatic polyester resin having a flow starting temperature of 200 ° C. or less at a load of 4.9 kN when a constant temperature increase test is performed at a temperature increase rate of 10 ° C./min is a terephthalic acid component unit as a main carboxylic acid component unit. The polyester resin-laminated polystyrene resin foam according to claim 1 or 2, which is a polyester copolymer containing an ethylene glycol component unit and a cyclohexanedimethanol component unit as main diol component units. The basis weight of the polyester-based resin-laminated polystyrene-based resin foam is 250 to 600 g / m ² , and the thickness of the film-like aromatic polyester-based resin is 30 to 200 μm. The polyester resin laminated polystyrene resin foam according to the description.   The adhesive layer is mainly composed of a mixture of a polystyrene-based resin and a polyester-based polymer, and the adhesive strength between the foamed sheet or foamed plate made of the polystyrene-based resin and the film-like aromatic polyester-based resin is 490 mN / cm or more. The polyester resin-laminated polystyrene resin foam according to any one of claims 1 to 4.   The adhesive layer has a polyolefin polymer or a mixture of a polyolefin polymer and a polystyrene resin as a main component, and has an adhesive strength between a foam sheet or a foam plate made of a polystyrene resin and a film-like aromatic polyester resin. It is 490 mN / cm or more, The polyester resin laminated polystyrene resin foam in any one of Claims 1-4 characterized by the above-mentioned.   The polyester resin-laminated polystyrene resin foam according to claim 6, wherein the polyolefin polymer is an ethylene-vinyl acetate copolymer having a melting point of 105 ° C or higher.   The polyester resin-laminated polystyrene resin foam according to any one of claims 1 to 7, wherein a film-like polyolefin resin is laminated and bonded onto the film-like aromatic polyester resin.