JP4144916B2 - Thermoplastic resin foam injection molded body and method for producing the same - Google Patents

Thermoplastic resin foam injection molded body and method for producing the same Download PDF

Info

Publication number
JP4144916B2
JP4144916B2 JP07164497A JP7164497A JP4144916B2 JP 4144916 B2 JP4144916 B2 JP 4144916B2 JP 07164497 A JP07164497 A JP 07164497A JP 7164497 A JP7164497 A JP 7164497A JP 4144916 B2 JP4144916 B2 JP 4144916B2
Authority
JP
Japan
Prior art keywords
foam
injection
thermoplastic resin
carbon dioxide
pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP07164497A
Other languages
Japanese (ja)
Other versions
JPH10230528A (en
Inventor
馨 依田
功三 市川
茂雄 西川
晴夫 井上
公宣 末田
真男 江里口
英夫 雨宮
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsui Chemicals Inc
Original Assignee
Mitsui Chemicals Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsui Chemicals Inc filed Critical Mitsui Chemicals Inc
Priority to JP07164497A priority Critical patent/JP4144916B2/en
Publication of JPH10230528A publication Critical patent/JPH10230528A/en
Application granted granted Critical
Publication of JP4144916B2 publication Critical patent/JP4144916B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0037—Other properties
    • B29K2995/0063—Density

Landscapes

  • Injection Moulding Of Plastics Or The Like (AREA)
  • Molding Of Porous Articles (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は物性および表面外観の優れた熱可塑性樹脂発泡射出成形体の製造方法に関し、さらに詳細には、発泡剤として超臨界状態の二酸化炭素および／または窒素を用いた、微細な平均セル径と均一な平均セル密度のセルを有する発泡部分及びその表面に外観が良好で発泡部分と一体化した非発泡部分を有する熱可塑性樹脂発泡射出成形体の製造方法に関する。
【０００２】
【従来の技術】
熱可塑性樹脂発泡体は、化学発泡剤や物理的発泡剤を用いて製造する方法が知られている。
【０００３】
化学発泡法は、一般に原料樹脂と、成形温度で分解してガスを発生する低分子量の有機発泡剤を混合し、該発泡剤の分解温度以上に加熱することにより発泡成形する方法である。この方法は、ガスの発生が分解温度に対してシャープであり、分解温度も発泡助剤等を添加することによって容易に調製できる上に、独立気泡を有する発泡体を得ることができる。
【０００４】
しかし、これらの発泡体は、特殊な発泡剤を用いるためコストが高くなることに加えて、発泡体中に残存する発泡剤の分解残留物のために、発泡体の変色、臭気の発生、食品衛生上の問題などを生じる。また、化学発泡剤が原因である成形機の汚れおよびそれに伴う成形不良についても問題となっている。
【０００５】
これに対し、物理的発泡法であるガス発泡法は、成形機で樹脂を溶融したところに、ブタン、ペンタン、ジクロロジフロロメタンのような低沸点有機化合物を供給し、混練した後、低圧域に放出することにより発泡成形する方法である。この方法に用いられる低沸点有機化合物は、樹脂に対して親和性があるため溶解性に優れ、また、保持性にも優れていることから、高倍率発泡体を得ることができるという特徴を持っている。しかしながら、これらの発泡剤は、コストが高いことに加え、可燃性や毒性等の危険性を有しており、大気汚染の問題を生じる可能性を持っている。また、ジクロロジフロロメタンをはじめとするフロン系ガスはオゾン層破壊の環境問題から全廃の方向へ進んでいる。
【０００６】
このような従来法の問題点を解決する為に、クリーンでコストがかからない炭酸ガス、窒素等の不活性ガスを発泡剤とする方法が数多く提案されている。しかしながら、該不活性ガスは樹脂との親和性が低いことから、溶解性に乏しい。このため発泡体は、気泡径が大きく、不均一で、セル密度が小さいため、外観性、機械的強度、断熱性、発泡倍率の点に問題があった。
【０００７】
またストラクチュラルフォームを成形するための射出発泡成形においてもこれまで種々の手法が提案されている。これらの手法により得られる発泡体は、表面のスキン層と中間のコア層からなるサンドイッチ構造を形成するため、同重量樹脂の比較では、発泡により体積が増大する効果により、通常の射出成形品よりも３ないし４倍の剛性が得られる。しかしながら、これらの手法において製造される発泡体のセル径は５０から１００μmと大きく、またセル径が不均一であるため、衝撃強度試験においてはセルが破壊の起点となり、強度の低下を伴うことが指摘されている。
【０００８】
これらの問題を解決する技術として、米国特許４４７３６６５号公報には、２〜２５μmの径を有する微細なセルを均一に分散させた発泡成形体を得るための製造方法が記載されている。この方法では、まず、加圧下で、不活性ガスを熱可塑性樹脂製シート中に飽和するまで含浸させる。その後、熱可塑性樹脂のガラス転移温度まで熱してから、減圧して、樹脂に含浸しているガスを過飽和状態にして、セル核を生成し、急冷することによって、セルの成長を制御する。または、予め、加圧下で不活性ガスを飽和させた熱可塑性樹脂を加熱溶融して加圧下で賦形したのち、冷却減圧しセル核を生成、冷却してセル径を制御する方法を用いた押出成形および射出成形による製造方法が例示されている。上記の方法によって、微細で多数のセルを有する発泡体を得ることができるが、不活性ガスは、樹脂との親和性が低いことから、樹脂中にガスを完全に含浸させるのに十数時間を要してしまい、工業的に実施するのは実質的に困難である。
【０００９】
米国特許５１５８９８６号公報には、発泡剤として超臨界流体を用い、これを熱可塑性樹脂に含浸させることにより、極めて微細なセル径と大きなセル密度を有する発泡体を得る技術が記載されている。超臨界液体は、液体に近い優れた溶解性と、気体に近い優れた拡散性を有するため樹脂への溶解性が高く、また樹脂中での拡散速度も大きいことから、短時間で発泡剤を樹脂中に含浸させることが可能となる。この公報では、熱可塑性樹脂を押出機によりシート化し、超臨界状態の二酸化炭素で満たされた加圧室に導入し、該シート中に二酸化炭素を含浸した後、大気圧下の発泡室においてヒーターで加熱し発泡させ、発泡体を得る方法と、押出機で樹脂を溶融したところへ超臨界状態の二酸化炭素を含浸させ、シート状に押し出した成形体を加圧室に導入し、その圧力変化によりセル核を生成し、加熱冷却により、セル径、セル密度を制御し、発泡体を得る方法が提案されている。
【００１０】
しかしながら、いずれの方法も大規模な高圧設備が必要であり、莫大な設備コストを要し、作業効率も悪く、工業化するのは困難である。また前者の方法は、シート状の成形体に直接含浸させるため、二酸化炭素を成形体に完全に浸透させるには長時間を要し、後者の方法は、溶融樹脂中に含浸させるため、前者の方法よりは二酸化炭素の浸透速度は速いが、押出機一台の混練だけで、二酸化炭素の相溶化と多数のセル核の生成を行うことは難しく、微細で多数のセルを有する発泡体を得ることは困難であった。
【００１１】
本発明者らは、特開平８−１１１９０号公報において、第１押出機とこれに繋がる混合部を有するアダプターにより、溶融した熱可塑性樹脂に発泡剤である不活性ガスを含浸させ、熱可塑性樹脂と不活性ガスの相溶状態を形成するガス溶解工程と、第２押出機により、加圧状態を維持したまま、溶融樹脂の温度を下げる冷却工程と、急激な圧力低下により多数のセル核を発生させる核発生工程と、セル径を制御する発泡制御工程からなることを特徴とする微細で多数のセルを均一に有する熱可塑性樹脂発泡体の発泡押出成形による製造方法を提案した。
【００１２】
この製造方法では、米国特許４４７３６６５号公報や米国特許５１５８９８６号公報に記載の製造方法では実質上極めて困難な発泡体の製造を、連続的に行うことが可能である。しかしながらこの製造方法は、核発生工程において溶融樹脂に高せん断を与えるためにダイスのリップ開度を極めて狭くする必要があり、薄物の発泡体を製造するには好適だが、比較的厚肉の発泡体を製造するのには適さないことが明らかになりつつある。また特開平８−１１１９０号公報には押出成形方法しか開示されていない。
【００１３】
また米国特許５１５８９８６号公報には、射出成形機シリンダー内で熱可塑性樹脂を溶融し超臨界の二酸化炭素を含浸させたのち、均一に分散したところで急激に加熱してセル核を生成し、発泡を制御するために高圧ガスの充填された金型内に、溶融樹脂を射出することで発泡体を得る方法が提案されている。
【００１４】
しかしながらこの方法においては
１） 射出成形機のみで、樹脂溶融、二酸化炭素混練、射出を行うため、また射出の際には樹脂の計量が停止するために、連続的に供給される二酸化炭素供給の定量性の確保と、熱可塑性樹脂と二酸化炭素の混合比を一定に保つのが困難である。
２） 通常の射出成形機のみでは、計量終了後スクリュウ背圧が停止するため、相溶状態の熱可塑性樹脂と二酸化炭素が分離してしまい、金型内に射出した時にセルの微細化が難しい。
等の欠点があり、その結果、物性測定用試験片程度の小さな成形品では、微細なセルの発泡体が得られるものの、大型の成形品の場合には、均一で微細なセル径が得にくい等の問題があった。
【００１５】
【発明が解決しようとする課題】
本発明の目的は、発泡剤として二酸化炭素および／または窒素を用いて、微細な平均セル径と均一な平均セル密度のセルを有する発泡部と表面外観が良好で表層に該発泡部と一体化した非発泡部分を有する熱可塑性樹脂発泡射出成形体の製造方法を提供することである。
【００１６】
【課題を解決するための手段】
本発明者らは、微細な平均セル径と均一な平均セル密度のセルを有する発泡部と、表面外観が良好で表層に該発泡部と一体化した非発泡部分を有する熱可塑性樹脂発泡射出成形体について鋭意研究を重ねた結果、発泡剤を供給するラインを有する連続可塑化装置（１）に、射出プランジャー（６）を有する射出装置（７）を接続することで、熱可塑性樹脂と超臨界状態の二酸化炭素および／または窒素を充分に混練し、相溶状態にしたのち、急激な圧力低下を起こして連続的にしかも短時間で、表面外観が良好で発泡部と一体化した未発泡部分を表層に有する熱可塑性樹脂発泡射出成形体が製造できることを見いだし本発明に到達した。即ち、本発明は以下の実施態様を包含する。
【００１９】
（ａ）内層に平均セル径が０．０１〜５０μｍ、平均セル密度が１０ 8 〜１０ 16 個／ｃｍ 3 である発泡部分と、表層に前記発泡部分と一体化した厚さ１０〜１０００μｍの非発泡部分とを有する熱可塑性樹脂発泡射出成形体を製造する方法であって、
（I）発泡剤を供給するラインを有する連続可塑化装置（１）内で、１００〜４５０℃で熱可塑性樹脂１００重量部を溶融し、超臨界状態の二酸化炭素および／または窒素を、熱可塑性樹脂１００重量部当たり０．１〜３０重量部添加し、熱可塑性樹脂と超臨界状態の二酸化炭素および／または窒素の定量的混合溶解を継続し、相溶状態の溶融樹脂組成物を形成するガス溶解工程、
（II）連続可塑化装置（１）内で、前記二酸化炭素および／または窒素の臨界圧力以上の圧力を維持したまま該溶融樹脂組成物を５０〜３００℃の温度に下げる冷却工程、
（III）連続可塑化装置（１）に接続した射出プランジャー（６）を有する射出装置（７）により、前記二酸化炭素および／または窒素の臨界圧力以上の圧力を維持したまま冷却した該溶融樹脂組成物を計量し、金型（８）内に充填する計量射出工程、及び、
（IV）金型（８）内の圧力を前記二酸化炭素および／または窒素の前記臨界圧力以下の圧力に低下することによりセル核を発生させ、該セル径を制御する発泡制御工程からなり、計量射出工程までは、二酸化炭素および／または窒素の超臨界状態を維持し、かつ連続可塑化装置（１）によるガス溶解工程および冷却工程と射出装置（７）による計量射出工程を独立に行うことを特徴とする熱可塑性樹脂発泡射出成形体を製造する方法。
【００２０】
(b) 発泡剤を供給するラインを有する連続可塑化装置（１）と、射出プランジャー（６）を有する射出装置（７）の間に、開閉バルブ（５）を介して射出装置（７）に接続される該連続可塑化装置（１）の流出路に接続された、混合部を有するアダプター（２）を設けることを特徴とする(a)記載の熱可塑性樹脂発泡射出成形体の製造方法。
【００２１】
（ｃ） 厚さが０．５〜５０ｍｍの発泡体が製造可能な（ａ）記載の熱可塑性樹脂発泡射出成形体の製造方法。
【００２２】
（ｄ） 厚さが１０〜５０ｍｍの発泡体が製造可能な（ａ）記載の熱可塑性樹脂発泡射出成形体の製造方法。
【００２３】
（ｅ）発泡制御工程を、溶融樹脂組成物を射出したのちに金型（８）内に充填した高圧ガスの脱ガスおよび／または金型（８）のコアの少なくとも一部の後退で行う（ａ）記載の熱可塑性樹脂発泡射出成形体の製造方法。
【００２４】
（ｆ）熱可塑性樹脂にさらに整泡剤を０．１〜１０重量部添加することを特徴とする（ａ）記載の熱可塑性樹脂発泡射出成形体の製造方法。
【００２５】
(g) 発泡剤を供給するラインを有する連続可塑化装置（１）と、射出プランジャー（６）を有する射出装置（７）の間に、開閉バルブ（５）を介して射出装置（７）に接続される、プランジャーを有する樹脂アキュームレータ装置（４）を設けることを特徴とする(a)記載の熱可塑性樹脂発泡射出成形体の製造方法。
【００２６】
(h) 混合部を有するアダプター（２）と、射出プランジャー（６）を有する射出装置（７）の間に、開閉バルブ（５）を介して射出装置（７）に接続される、プランジャーを有する樹脂アキュームレータ装置（４）を設けることを特徴とする(g)記載の熱可塑性樹脂発泡射出成形体の製造方法。
【００２７】
【発明の実施の形態】
本発明者らは、上記目的の達成のため検討を行なった。本発明のために設計された図１の装置および方法について説明する。発泡剤を供給するラインを有する連続可塑化装置（１）に、開閉バルブ（５）を介して射出プランジャー（６）を有する射出装置（７）を接続した。この連続可塑化装置（１）に樹脂を移送し、加熱溶融しながら超臨界状態の二酸化炭素および／または窒素を導入し、相溶状態の溶融樹脂組成物を形成する。
【００２８】
この後該溶融樹脂組成物は、射出プランジャー（６）を有する射出装置（７）へと移送される。移送された後、開閉バルブ（５）を閉じることで、連続可塑化装置（１）と射出装置（７）は互いに独立した状態となる。連続可塑化装置（１）は、射出装置（７）が計量射出を行っている間も停止することなく、連続的に溶融樹脂組成物を形成する。なおこの間は射出装置（７）に計量しないため、連続可塑化装置（１）内の圧力は上昇するが、圧力の上昇によって溶融樹脂組成物の相溶状態が壊れることはないので、ガス溶解工程、冷却工程を継続することに問題はない。しかしながら連続可塑化装置（１）の耐圧能力に問題が生じる場合には、開閉バルブ（５）の作動で溶融樹脂組成物を系外に排出できる装置としておくことも、本発明の主旨を逸脱しない。
【００２９】
一方射出装置（７）は計量終了後射出を行うが、図５で示した通常の射出成形機においては計量終了後背圧が一旦切れてしまうが、本発明においては、計量開始から射出終了まで発泡剤の臨界圧力以上の背圧を常にかけた状態に維持する。このため、連続可塑化装置（１）で形成された溶融樹脂組成物は、発泡剤と樹脂が相分離する事無く金型（８）内へ射出される。
【００３０】
金型（８）内では、溶融樹脂組成物を射出したのちに金型（８）内に充填した高圧ガスの脱ガスおよび／または金型（８）コアの一部あるいは全部を後退することで発泡制御工程を行う。この時射出された樹脂の金型（８）と接触した部分は、冷却されることで実質的に１μｍ以上のセルが存在しない緻密な非発泡層として、発泡成形品の表面部分に一体化して形成されることで、発泡射出成形品の断面は図７に示すような構造となる。
【００３１】
また本発明の実施態様の一つを図２に示す。発泡剤を供給するラインを有する連続可塑化装置（１）と、射出プランジャー（６）を有する射出装置（７）の間に、開閉バルブ（５）を介して射出装置（７）と接続される該連続可塑化装置（１）の流出路に接続された、混合部を有するアダプター（２）を設けることは、溶融熱可塑性樹脂と二酸化炭素および／または窒素の混合をさらに進行させ、熱可塑性樹脂と二酸化炭素および／または窒素の相溶状態の形成が容易になること、および該アダプター（２）の温度制御により溶融状態にある樹脂を、この後の射出、発泡に適した粘度になるよう冷却することが容易となる。この混合部を有するアダプター（２）については特に制限は無いが、樹脂の混練および冷却を行うことからスタティックミキサーを内蔵するアダプター（２）が好適に用いられる。
【００３２】
また本発明の実施態様の一つを図３に示す。射出プランジャー（６）を有する射出装置（７）の前に、開閉バルブ（５）を介して射出装置（７）と接続される、プランジャーを有する樹脂アキュームレータ装置（４）を設けることで、計量終了後、該開閉バルブ（５）が閉に切り替わり、該射出プランジャー（６）によって、金型（８）内への射出を行う間、連続可塑化装置（１）から送られてくる溶融樹脂は、該開閉バルブ（５）直前に備えられている樹脂アキュームレータ装置（４）へと送られ、該溶融樹脂の流入によって、樹脂アキュームレータ装置（４）のプランジャーが後退するという該樹脂アキュームレータ装置（４）の制御により、装置系内を所定圧力に維持することが容易となるため、溶融樹脂組成物の相溶状態の維持が容易となり発泡射出成形体のセル径を微細にすることが容易となるため好ましい。
【００３３】
また本発明の実施態様の一つを図４に示す。さらに同様にプランジャーを有する樹脂アキュームレータ装置（４）に代えてもう一台の射出プランジャー（６）を有する射出装置（７）を設けることも可能であり、装置系内を所定圧力に維持することが容易となるため、溶融樹脂組成物の相溶状態の維持が容易となり発泡射出成形体のセル径を微細にすることが容易となるため好ましい。
【００３４】
本発明に用いられる熱可塑性樹脂としては、可塑化する温度が１００〜４５０℃の熱可塑性樹脂であれば特に制限無く使用でき、例えばスチレン系樹脂、（例えば、ポリスチレン、ブタジエン・スチレン共重合体、アクリロニトリル・スチレン共重合体、アクリロニトリル・ブタジエン・スチレン共重合体等）、ＡＢＳ樹脂、ポリエチレン、ポリプロピレン、エチレン−プロピレン樹脂、エチレン−エチルアクリレート樹脂、ポリ塩化ビニル、ポリ塩化ビニリデン、ポリブテン、ポリカーボネート、ポリアセタール、ポリフェニレンオキシド、ポリビニルアルコール、ポリメチルメタクリレート、飽和ポリエステル樹脂（例えば、ポリエチレンテレフタレート、ポリブチレンテレフタレート等）、生分解性ポリエステル樹脂（例えば、ポリ乳酸のようなヒドロキシカルボン酸縮合物、ポリブチレンサクシネートのようなジオールとジカルボン酸の縮合物等）ポリアミド樹脂、ポリイミド樹脂、フッ素樹脂、ポリサルフォン、ポリエーテルサルフォン、ポリアリレート、ポリエーテルエーテルケトン、液晶ポリマー等の１種または２種以上の混合物が挙げられる。これらの熱可塑性樹脂中では、スチレン系樹脂、ポリオレフィン系樹脂が好ましく、特にポリスチレン、ポリプロピレンが好ましい。
【００３５】
さらにそれぞれの熱可塑性樹脂の加工温度付近で測定するメルトフローインデックスが０．０５〜６０ｇ／１０分、好ましくは０．１〜４０ｇ／１０分、さらに好ましくは０．２〜２０ｇ／１０分の程度の範囲にあることが好ましい。この場合の測定条件、即ち、測定温度や荷重はＡＳＴＭで規定された条件が目安となり、例えばポリプロピレンの場合は、２３０℃、２．１６kgf/cm2、ポリスチレンの場合は、２００℃、５．０kgf/cm2であり、その他ＡＳＴＭ Ｄ１２３８に定められた測定条件に従って測定する。
【００３６】
メルトフローインデックスが上記下限範囲付近以上では、溶融時の樹脂粘度が適当で、押出機の負荷が過大にならず、加工が容易である。また上記上限範囲付近以下であれば、樹脂が発泡時のガス圧に耐えて粘度を保持でき、破泡を生じないで微小なセルを生成することができる。この目安によって使用する樹脂のメルトインデックは適宜選択することができる。
【００３７】
熱可塑性樹脂として、例えばポリプロピレンやポリスチレン等のメルトフローインデックスが１０〜６０g/10分のものを使用した際には、高倍率の製品を得易い。またメルトフローインデックスが０．０５〜１０g/10分のものを使用した際には、冷却固化が速いため冷却時間の短縮が可能となり、生産性向上の効果が生じる。
【００３８】
本発明に発泡剤として用いられる超臨界状態の二酸化炭素および／または窒素の量は、熱可塑性樹脂組成物１００重量部に対して、０．１〜３０重量部、さらに好ましくは０．２〜２０重量部であることが好ましい。
【００３９】
発泡剤が０．１重量部以下では微細な平均セル径は得られず、また３０重量部以上においては発泡体表面に水膨れ状の外観不良が生じ、美麗な表面外観は得難い。
【００４０】
発泡剤として用いられる超臨界状態の二酸化炭素または窒素は単独で使用できるが、二酸化炭素と窒素を混合して使用しても良い。この場合、その混合比率はモル比で１：９〜９：１の範囲であることが好ましい。発泡体に使用する熱可塑性樹脂が、ＰＥＴ、ＰＢＴ、ポリ乳酸等のポリエステル系樹脂、ポリカーボネート、ポリアミド等の場合、発泡剤を二酸化炭素を単独で使用するよりも、二酸化炭素と窒素を併用する方が、セルの微細化、高セル密度化しやすく好ましい。
【００４１】
射出成形機内で樹脂組成物の溶融物中に発泡剤を混合する方法としては、例えば気体状態の二酸化炭素および／または窒素を直接あるいは加圧状態で注入する方法、液体状態の二酸化炭素および／または窒素をプランジャーポンプ等で注入する方法等があげられる。
【００４２】
これら二酸化炭素および／または窒素は、溶融樹脂組成物中への溶解性、浸透性、拡散性等の観点から、成形機内部で超臨界状態となっている必要がある。
【００４３】
また本発明では、熱分解により二酸化炭素または窒素を発生する熱分解型発泡剤を発泡核剤として併用することも可能であり、その例としてアゾジカルボンアミド、Ｎ，Ｎ−ジニトロソペンタテトラミン、アゾビスイソブチロニトリル、クエン酸、重曹等が挙げられる。
【００４４】
本発明に用いる熱可塑性樹脂に、セル径を微細にするために、各種整泡剤の１種又はそれ以上を添加することが可能であるが、該整泡剤としては通常の発泡成形で使用されている公知のものが使用できるが、例えばオルガノポリシロキサンまたは脂肪族カルボン酸のフルオロアルカンエステルが好適に用いられる。
【００４５】
オルガノポリシロキサンとしては、ポリジメチルシロキサン、ポリジフェニルシロキサン、ポリメチルフェニルシロキサン、ポリメチルハイドロジェンシロキサン、これらオルガノポリシロキサンをエポキシ基含有化合物、アミノ基含有化合物、エステル結合含有化合物等によって変性した変性オルガノポリシロキサン等が挙げられる。なかでも樹脂中への分散性、溶解性、表面外観改良の効果等の観点から、ポリジメチルシロキサンが好ましい。
【００４６】
変性オルガノポリシロキサンを使用する場合には、過酸化物等のラジカル発生剤を添加することで、樹脂との相溶性を向上することが可能である。
【００４７】
また脂肪族カルボン酸のフルオロアルカンエステルとしては、炭素数が３から３０の脂肪族カルボン酸と炭素数３〜３０のアルキル基より誘導されたフロロアルカン基を有するフロロアルカンエステルで、脂肪族カルボン酸としては、例えばラウリン酸、ステアリン酸、クロトン酸、オレイン酸、マレイン酸、グルタル酸、モンタン酸等が好適であり、樹脂中への分散性、溶解性、表面外観改良の効果等の観点から、モンタン酸のフルオロアルカンエステルが好ましく、なかでもモンタン酸のパーフルオロアルカンエステルが特に好ましい。
【００４８】
これら整泡剤の添加量は熱可塑性樹脂に対して０．１〜１０重量部、好ましくは０．２〜８重量部さらに好ましくは０．３〜５重量部の範囲にあることが好ましい。
【００４９】
整泡剤の添加量が、０．１重量％以上では発泡体のセル微細化が容易であり、また１０重量部以下では、樹脂が発泡時のガス圧に耐えるだけの粘度を保持でき、破泡を生じないで微小なセルを生成することができる。
【００５０】
また本発明には熱可塑性樹脂組成物の添加剤として発泡核剤として作用する無機微粉末を使用することが可能である。この例としては、無機微粉末は、タルク、炭酸カルシウム、クレー、酸化マグネシウム、酸化亜鉛、ガラスビーズ、ガラスパウダー、酸化チタン、カーボンブラック、無水シリカ等があげられ、好ましくはタルク、炭酸カルシウム、酸化チタン、無水シリカであり、特に好ましくはタルクである。その粒径は５０μm以下が好ましく、さらに好ましくは１０μm以下、特にに好ましくは５μm以下である。
【００５１】
上記樹脂組成物には、本発明の特性を損なわない範囲において、組成物中に例示した無機微粉末、脂肪族カルボン酸およびその誘導体以外にエチレン−プロピレンゴム、エチレン−ブテンゴム、プロピレン−ブテンゴム、スチレン−ブタジエンジブロック共重合体の水素添加物、スチレン−ブタジエン−スチレントリブロック共重合体の水素添加物、スチレン−イソプレンジブロック共重合体の水素添加物、スチレン−イソプレン−スチレントリブロック共重合体の水素添加物、低密度ポリエチレン、高密度ポリエチレン、直鎖状低密度ポリエチレン、超低密度ポリエチレン、エチレン−エチルアクリレート共重合体、エチレン−酢酸ビニル共重合体、ポリブテン等の各種エラストマー、可塑剤、顔料、安定剤、充填剤、金属粉等を目的、用途に応じ適宜使用することが可能である。
【００５２】
本発明の熱可塑性樹脂発泡射出成形体の原料となる熱可塑性樹脂組成物の製造方法については特に制限はなく、通常公知の方法を採用することができる。例えば、熱可塑性樹脂と、必要によりオルガノポリシロキサンや脂肪族カルボン酸のフルオロアルカンエステル等の添加剤を高速攪拌機等で均一混合した後、十分な混練能力のある一軸あるいは多軸の押出機、混合ロール、ニーダー、ブラベンダー等で溶融混練する方法等で製造できる。また熱可塑性樹脂とオルガノポリシロキサンや脂肪族カルボン酸のフルオロアルカンエステル等を均一混合した状態で使用することも差し支えない。
【００５３】
本発明における熱可塑性樹脂組成物および二酸化炭素および／または窒素の相溶状態を形成するガス溶解工程とは、図１に示した熱可塑性樹脂発泡射出成形体の製造方法の例においては、連続可塑化装置（１）内で樹脂組成物を加熱溶融したのち、該溶融樹脂組成物中に超臨界状態の二酸化炭素および／または窒素を添加し、均一に混合する工程であり、冷却工程とは、溶融状態にある樹脂組成物を冷却し、射出、発泡に適した粘度になる様調整する工程である。
【００５４】
該ガス溶解工程および冷却工程は、図２に示した熱可塑性樹脂発泡射出成形体の製造方法の例においては、連続可塑化装置（１）およびアダプター（２）で行う。また図３に示した熱可塑性樹脂発泡射出成形体の製造方法の例においては、連続可塑化装置（１）、アダプター（２）および樹脂アキュームレータ装置（４）で行う。
【００５５】
計量射出工程とは、射出、発泡に適した粘度になる様、温度制御された樹脂組成物を射出装置（７）に計量し、該射出プランジャー（６）で射出を行う工程であり、発泡制御工程とは、金型（８）内に射出された樹脂組成物を加圧下より圧力低下させ、セル核を発生させかつセル径の大きさを制御する工程である。これらのうち少なくとも、ガス溶解工程および冷却工程は、特開平８−１１１９０号公報記載の特許請求の範囲及び各実施例に記載の方法に準じ、以下の様に行う。
【００５６】
熱可塑性樹脂を、ホッパー（９）より連続可塑化装置（１）中に供給し、１００〜４５０℃に加熱溶融させる。また、二酸化炭素および／または窒素は、ガスボンベ（１０）より昇圧ポンプ（１１）に輸送され、そこで昇圧され、圧力制御された二酸化炭素および／または窒素を連続可塑化装置（１）内の溶融樹脂組成物中に供給する。このとき、連続可塑化装置（１）内に存在する二酸化炭素および／または窒素が、樹脂組成物に対する溶解拡散を大幅に高め、短時間で樹脂組成物中に浸透することを可能とするため、系内を該二酸化炭素および／または窒素の臨界圧力以上および臨界温度以上に維持する。また、連続可塑化装置（１）内に供給された二酸化炭素および／または窒素は、昇温昇圧され超臨界状態となるか、あるいは連続可塑化装置（１）に供給される以前に昇温昇圧され、超臨界状態となってから供給される。
【００５７】
連続可塑化装置（１）内で溶融樹脂組成物と二酸化炭素および／または窒素とがスクリュウ（１２）により混練され、熱可塑性樹脂組成物と二酸化炭素および／または窒素の相溶状態を形成させる。相溶後冷却工程において、連続可塑化装置（１）先端の温度制御で、溶融状態にある樹脂組成物を５０〜３００℃好ましくは８０〜２８０℃で且つ溶融樹脂組成物の可塑化温度以上に冷却し、この後の射出、発泡に適した粘度になるよう調整する。
【００５８】
本発明の第１〜第４実施例を図により以下に説明する。図１〜４において、（１）は連続可塑化装置、（２）はアダプター、（３）は樹脂アキュームレータプランジャー、（４）は樹脂アキュームレータ装置、（５）は開閉バルブ、（６）は射出プランジャー、（７）は射出装置、（８）は金型、（９）はホッパー、（１０）はガスボンベ、（１１）は昇圧ポンプ、（１２）はスクリュウ、（１３）はガスボンベ、（１４）は圧力制御バルブ、（１５）は開閉バルブである。
【００５９】
図１において、ガス溶解工程において、熱可塑性樹脂１００重量部を、ホッパー（９）より連続可塑化装置（１）中に供給し、加熱溶融させる。また、二酸化炭素および／または窒素は、ガスボンベ（１０）より昇圧ポンプ（１１）に輸送され、そこで昇圧され、圧力制御された二酸化炭素および／または窒素０．１〜３０重量部が連続可塑化装置（１）内の溶融樹脂組成物中に供給され、ガス溶解工程を行う。このとき、連続可塑化装置（１）内に存在する二酸化炭素および／または窒素が、樹脂組成物に対する溶解拡散を大幅に高め、短時間で樹脂組成物中に浸透することを可能とするため、系内は該二酸化炭素および／または窒素の臨界圧力以上および臨界温度以上に維持されている必要がある。例えば、二酸化炭素の場合、臨界圧力は７５．３kg/cm2、臨界温度は３１．３５℃であり、また窒素の場合、臨界圧力は３３．５kg/cm2、臨界温度は−１４７．０℃であり、連続可塑化装置（１）内は、圧力が７５〜４００kg/cm2、好ましくは１００〜３００kg/cm2の範囲、温度は１００〜４５０℃、好ましくは１１０〜２８０℃の範囲が好ましい。
【００６０】
また、連続可塑化装置（１）内に供給された二酸化炭素および／または窒素は、昇温昇圧され超臨界状態となるか、あるいは連続可塑化装置（１）に供給される以前に昇温昇圧され、超臨界状態となってから供給されても構わない。
【００６１】
連続可塑化装置（１）内で溶融樹脂組成物と二酸化炭素および／または窒素とがスクリュウ（１２）により混練され、熱可塑性樹脂組成物と二酸化炭素および／または窒素の相溶状態を形成させる。相溶後冷却工程において、連続可塑化装置（１）先端の温度制御で、溶融状態にある樹脂組成物を５０〜３００℃好ましくは８０〜２８０℃で且つ溶融樹脂組成物の可塑化温度以上に冷却し、この後の射出、発泡に適した粘度になるよう調整する。
【００６２】
射出、発泡に適した粘度になる様に温度制御された溶融樹脂組成物は、計量射出工程において、開閉バルブ（５）を介して接続された射出プランジャー（６）を有する射出装置（７）へと送られる。該開閉バルブ（５）が開にあるとき、溶融樹脂組成物の射出装置（７）中への流入で、該射出プランジャー（６）の後退することによって計量される。通常の射出成形装置においては、計量終了後に直ちに背圧は停止するが本発明では、この時該射出装置（７）内で溶融樹脂組成物が発泡しないよう、射出終了後まで背圧をかけ系内圧力を制御し続ける必要がある。このときの背圧は、二酸化炭素および／または窒素の臨界圧力以上である必要がある。ガス溶解工程、冷却工程および計量射出工程の一連の工程が終了するまでは、常に発泡剤の臨界圧力以上の圧力を維持し、溶融樹脂組成物が樹脂とガスに分離してしまうことのないようにする必要がある。一旦樹脂とガスが分離した後には、再度系内圧力を上昇しても、樹脂とガスの相溶状態にはならないため、セルの微細化が不可能になる。
【００６３】
計量終了後、該開閉バルブ（５）が閉に切り替わり、樹脂とガスの相溶混合物は該射出プランジャー（６）によって、金型（８）内への射出を行う。計量後射出を行う前に該射出プランジャー（６）をサックバックさせることで、射出装置（７）内の圧力をわずかに低下させることでセル核の生成を誘発する方法も好適に用いられる。
【００６４】
該開閉バルブ（５）が閉に切り替わり、樹脂とガスの相溶混合物は該射出プランジャー（６）によって、金型（８）内への射出を行う間、連続可塑化装置（１）は射出工程とは独立して樹脂組成物の溶融、および二酸化炭素および／または窒素の供給混練を行うため、熱可塑性樹脂と二酸化炭素および／または窒素の定量的な混合溶解を継続する事が可能なため、常に連続可塑化装置（１）内を発泡剤の臨界圧力以上に維持することができ、計量射出工程終了後、開閉バルブ（５）が開に切り替わると、直ちに連続可塑化装置（１）より射出装置（７）へ冷却された溶融樹脂組成物が送られ、計量工程が開始される。
【００６５】
なお微細な平均セル径で均一な平均セル密度のセルを有する発泡体を製造するためには、少なくともガス溶解工程、冷却工程、計量射出工程において、二酸化炭素および／または窒素は超臨界状態である必要がある。
【００６６】
射出される直前の金型（８）内には、ガスボンベ（１３）あるいは昇圧ポンプより圧力制御バルブ（１４）を介して供給される高圧ガスを所定の圧力で充填しておく。例えば、高圧ガスとして窒素を使用する場合、発泡剤として使用する二酸化炭素および／または窒素の臨界圧力以上の圧力であることが好ましい。
【００６７】
発泡制御工程において、該高圧ガスを充填させた金型（８）内に熱可塑性樹脂組成物と二酸化炭素および／または窒素の相溶状態を形成した溶融樹脂組成物を射出する。射出後、金型（８）内に充填した高圧ガスを急速に抜くことにより、金型（８）内に急激な圧力低下を生じさせる。該工程により、樹脂に含浸しているガスは、過飽和状態となり、多数のセル核が生じる。
【００６８】
セル径は、金型（８）温度、金型（８）内圧力、および圧力低下速度により、制御することが可能であり、平均セル径が０．０１〜５０μｍ、好ましくは０．０１〜２０μｍ、より好ましくは０．１〜２０μｍ、さらに好ましくは１〜２０μｍ、平均セル密度が１０8〜１０16個／cm3である、好ましくは１０8〜１０14個／cm3、さらに好ましくは１０8〜１０12個／cm3、表層に実質的に１μｍ以上のセルが存在しない、厚さ１０〜１０００μｍの非発泡部分を有する熱可塑性樹脂発泡射出成形体を得る。
【００６９】
また金型（８）内で急激な圧力低下を生じさせる方法として、金型（８）内に熱可塑性樹脂組成物と二酸化炭素および／または窒素の相溶状態を形成した溶融樹脂組成物を射出したのち、コアの一部または全部を後退させ、金型（８）内の容量を急激に増し、金型（８）内に急激な圧力低下を生じさせる方法も好適に用いられる。
【００７０】
これら発泡を制御する方法はそれぞれ単独であっても十分な発泡制御効果が得られるが、２つの方法を併用することには何ら支障はない。
【００７１】
図２に示すように、発泡剤を供給するラインを有する連続可塑化装置（１）と、射出プランジャー（６）を有する射出装置（７）の間に、開閉バルブ（５）を介して射出装置（７）と接続される該連続可塑化装置（１）の流出路に接続された、混合部を有するアダプター（２）を設けることは、溶融熱可塑性樹脂と二酸化炭素および／または窒素の混合をさらに進行させ、熱可塑性樹脂と二酸化炭素および／または窒素の相溶状態の形成が容易になること、および該アダプター（２）の温度制御により溶融状態にある樹脂を、この後の射出、発泡に適した粘度になるよう冷却することが容易となり、ガス溶解工程および冷却工程が容易に行えることから好ましい。この混合部を有するアダプター（２）については特に制限は無いが、樹脂の混練および冷却を行うことからスタティックミキサーを内蔵するアダプター（２）が好適に用いられる。
【００７２】
また図３に示すように、射出プランジャー（６）を有する射出装置（７）の前に、開閉バルブ（５）を介して射出装置（７）と接続される、プランジャーを有する樹脂アキュームレータ装置（４）を設けることは、計量終了後、該開閉バルブ（５）が閉に切り替わり、該射出プランジャー（６）によって、金型（８）内への射出を行う間、連続可塑化装置（１）から送られてくる溶融樹脂は、該開閉バルブ（５）直前に備えられている樹脂アキュームレータ装置（４）へと送られ、該溶融樹脂の流入によって、樹脂アキュームレータ装置（４）のプランジャーが後退するという該樹脂アキュームレータ装置（４）の制御により、装置系内を所定圧力に維持することが容易となるため、溶融樹脂組成物の相溶状態の維持が容易となり発泡射出成形体のセル径を微細にすることが容易となるため好ましい。
【００７３】
また図４に示すように、プランジャーを有する樹脂アキュームレータ装置（４）に代えてもう一台の射出プランジャー（６）を有する射出装置（７）を設けることも、装置系内を所定圧力に維持することが容易となるため、溶融樹脂組成物の相溶状態の維持が容易となり発泡射出成形体のセル径を微細にすることが容易となるため好ましい。
【００７４】
本発明の方法では、発泡剤である二酸化炭素および／または窒素を連続可塑化装置（１）中の溶融樹脂に供給、十分に混練したのち、開閉バルブ（５）を介して射出プランジャー（６）を有する射出装置（７）に計量し射出成形することから、射出中においても該開閉バルブ（５）が閉に切り替わり連続可塑化装置（１）は射出工程とは独立して樹脂の溶融および、二酸化炭素および／または窒素の供給混練を行うことが可能であるため、系内の圧力調整が容易であるため、発泡射出成形体のセル径を微細にすることが容易となり、連続的にしかも短時間のうちに微細で多数の気泡を均一に有する熱可塑性樹脂発泡射出成形体の製造が可能になる。
【００７５】
本発明により、表面外観が良好で一体化した非発泡部分を表層に有する熱可塑性樹脂発泡射出成形体を、効率良く製造することが可能になる。
【００７６】
図７に本発明の熱可塑性樹脂発泡射出成形体の断面の一例を示した。該成形体は、表層部に、発泡した内層部と一体化した非発泡部分を有した構造となっており、表層の非発泡部の厚みは約１０〜約１０００μｍである。この非発泡部分は、溶融樹脂組成物が射出により金型内に導入され、金型と接触することにより冷却され生成するものである。また発泡体の厚みは０．５〜５０ｍｍであり、好ましくは１〜４０ｍｍ、さらに好ましくは２〜３０ｍｍである。本発明では、溶融樹脂組成物を射出成形する金型キャビティーの厚みを予め調整しておくことで任意の厚みの発泡射出成形体を得ることが可能なため、発泡押出成形では製造困難な厚み１０ｍｍ以上、さらには１５ｍｍ以上の発泡体も容易に製造可能である。
【００７７】
以下実施例にて本発明を説明するが、本発明の内容はこれに限定されるものではない。
【００７８】
図１は実施例１および４を示す連続可塑化装置、射出装置、金型の断面図の一例である。図２は実施例２を示す連続可塑化装置、アダプター、射出装置、金型の断面図の一例である。図３は実施例３を示す連続可塑化装置、アダプター、樹脂アキュームレータ装置、射出装置、金型の断面図の一例である。図４は本発明の熱可塑性樹脂発泡射出成形体の製造方法を示す一例である。図５は、比較例３の熱可塑性樹脂発泡体の製造方法を表す一例である。図６は比較例４〜６の熱可塑性樹脂発泡体の製造方法を表す一例である。図７は本発明の熱可塑性樹脂発泡射出成形体の断面の一例である。図８は発泡押出成形により製造される熱可塑性樹脂発泡体の断面の一例である。
【００７９】
【実施例】
なお、実施例および比較例に記した物性評価は次の方法にしたがって実施した。
【００８０】
１）表面外観
射出成形時の金型（８）内冷却時間を６０秒に設定し成形した発泡体の表面が目視観察で一様で均一な場合で、かつ発泡体の断面観察で表層部分に一体化した非発泡部分がある場合を○、水膨れ状の膨れがある等○以外の場合を×とした。
【００８１】
２）平均セル径
走査型電子顕微鏡により撮影した写真を画像処理し、求めたセルの円相当径をセルの平均径とした。
【００８２】
３）平均セル密度
連続的に熱可塑性樹脂発泡射出成形体を成形し、成形品１０本毎にサンプルを３点取得した。３点のサンプルの写真を、走査型電子顕微鏡により撮影し、写真を画像処理して５００μm四方の中にあるセル数から１cm2当たりのセル数を算出し、それを２分の３乗した値をセル密度とし、３点の平均を平均セル密度とした。
【００８３】
４）セルの均一性
走査型電子顕微鏡により撮影した写真５００μm四方中の最大のセルの径が、平均セル径の１．５倍以下の場合で、且つ測定した３点のセル密度が平均セル密度の２／３〜１．５倍以内の場合を◎、平均セル径の２倍以下の場合で、且つ測定した３点のセル密度が平均セル密度の１／２〜２倍以内の場合を○、それ以外を×とした。
【００８４】
５）表層厚み
走査型電子顕微鏡により撮影した発泡体の断面写真より、非発泡の表層部分の厚みを測定した。
【００８５】
６）アイゾット衝撃強度
実施例および比較例で成形したダンベル片を切削加工し、ＪＩＳ Ｋ７１１０に準拠し、幅２ｍｍ、厚さ４ｍｍの２号Ａノッチ入りアイゾット衝撃試験片を作製、アイゾット衝撃試験を行い、同一形状の非発泡試験片に対する強度比を測定した。なお強度の対比となるポリスチレンの非発泡試験片のアイゾット衝撃強度は、トーポレックス５５５−５７（三井東圧化学（株）製）が１．７６kg-cm/cm2、トーポレックス５２５−５１（三井東圧化学（株）製）が１．５４kg-cm/cm2、トーポレックス５７５−５７（三井東圧化学（株）製）１．８３kg-cm/cm2であった。
【００８６】
実施例１
２００℃、５kgにおけるメルトフローインデックスが２．６g／10分であるポリスチレン樹脂（三井東圧化学（株）製、トーポレックス５５５−５７）のペレット１００重量部をホッパー（９）より口径３０mm、Ｌ／Ｄ＝３０のスクリュウ（１２）を持つ連続可塑化装置（１）中に供給し、２３０℃で加熱溶融し、昇圧ポンプ（１１）により１８０kg/cm2に昇圧し超臨界状態とした二酸化炭素１５重量部を、該樹脂が完全に溶融したところに供給した。連続可塑化装置（１）中で二酸化炭素と溶融樹脂を混練溶解させ、溶融樹脂組成物の樹脂温度を徐々に１５０℃まで冷却し、１５０℃に設定した射出装置（７）へ計量後、５０℃に設定した金型（８）内に射出した。このとき、射出される直前の金型（８）内には、窒素ガスを８０kg/cm2の圧力下で充填させておいた。射出終了後、金型（８）内に充填させた窒素ガスを１秒間で抜き、さらに金型（８）のコアを２mm後退させることで、樹脂発泡成形体である引張試験用ダンベル片（試験片厚み４mm）を得た。
【００８７】
発泡体の評価の結果を表１に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【００８８】
実施例２
実施例１において、連続可塑化装置（１）の流出路にスタティックミキサーを内蔵するアダプター（２）を接続し、アダプター（２）の温度を、流れ方向から順に、２００℃、１６０℃、１２０℃と設定し、溶融樹脂組成物の樹脂温度を１２０℃とした以外は実施例１に従いポリスチレン樹脂発泡成形体である引張試験用ダンベル片を得た。
【００８９】
発泡体の評価の結果を表１に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【００９０】
実施例３
実施例２において、アダプター（２）の流出路に樹脂アキュームレータ装置（４）を接続した以外は実施例２に従いポリスチレン樹脂発泡成形体である引張試験用ダンベル片を得た。
【００９１】
発泡体の評価の結果を表１に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【００９２】
実施例４
実施例１において、金型（８）内の圧力を急激に変化させる方法として、射出される直前の金型（８）内に、窒素ガスを８０kg/cm2の圧力下で充填させておく方法に代えて、射出終了後、金型（８）内のコアを急速に後退し減圧した以外は実施例１に従いポリスチレン樹脂発泡成形体である引張試験用ダンベル片を得た。
【００９３】
発泡体の評価の結果を表１に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【００９４】
実施例５
実施例１において、金型（８）の温度を２０℃とした以外は実施例１に従いポリスチレン樹脂発泡成形体である引張試験用ダンベル片を得た。
【００９５】
発泡体の評価の結果を表１に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【００９６】
実施例６
実施例１において、金型（８）の温度を８０℃とした以外は実施例１に従いポリスチレン樹脂発泡成形体である引張試験用ダンベル片を得た。
【００９７】
発泡体の評価の結果を表１に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【００９８】
実施例７
実施例１において、炭酸ガス量を５重量部とした以外は実施例１に従いポリスチレン樹脂発泡成形体である引張試験用ダンベル片を得た。
【００９９】
発泡体の評価の結果を表１に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【０１００】
比較例１
実施例１において、射出される直前の金型（８）内に高圧の窒素ガスを充填することなく、常圧の空気のままとし、金型のコアを予め後退して厚さ４ｍｍとしたこと以外は、実施例１に従いポリスチレン樹脂発泡成形体である引張試験用ダンベル片を得た。
【０１０１】
発泡体の評価の結果を表１に示す。アイゾット衝撃強度が低く、表面外観不良、微細な平均セル径なセルではない、セル数が少ない等の点で好ましくなく、本発明で意図する発泡体は製造不可能であった。
【０１０２】
比較例２
実施例１において、射出工程の間連続可塑化装置（１）で、二酸化炭素と溶融樹脂を混練溶解を行わず、射出工程終了後に混練溶解を再度開始したこと以外は、実施例１の方法に従いポリスチレン樹脂発泡成形体である引張試験用ダンベル片を得た。
【０１０３】
発泡体の評価の結果を表１に示す。アイゾット衝撃強度が低く、表面外観不良、微細な平均セル径なセルではない、セル数が少ない等の点で好ましくなく、本発明で意図する発泡体は製造不可能であった。
【０１０４】
またこの発泡体の断面を走査型電子顕微鏡で観察したところ、径が５０から１００μｍの不均一な気泡が分散していた。
【０１０５】
比較例３
２００℃、５kgにおけるメルトフローインデックスが２．６g／10分であるポリスチレン樹脂（三井東圧化学（株）製、トーポレックス５５５−５７）のペレット１００重量部を、図５に示す口径３０mm、Ｌ／Ｄ＝３０のスクリュウを持つインライン型射出成形機（シリンダー温度２３０〜１５０℃）に供給し、２３０℃で加熱溶融し、昇圧ポンプ（１１）により１８０kg/cm2に昇圧し超臨界状態とした二酸化炭素１５重量部を、該樹脂が完全に溶融したところに供給した。計量後はスクリュウの回転は停止し、ガス溶解工程及び冷却工程は中断された。またスクリュウの停止に伴いスクリュウ背圧は解除された。計量後溶融樹脂を、５０℃に設定した金型（８）内に射出した。このとき、射出される直前の金型（８）内には、窒素ガスを８０kg/cm2の圧力下で充填させておいた。射出終了後、金型（８）内に充填させた窒素ガスを１秒間で抜き、さらに金型（８）のコアを２mm後退させることで、樹脂発泡成形体である引張試験用ダンベル片（試験片厚み４mm）を得た。
【０１０６】
発泡体の評価の結果を表１に示す。アイゾット衝撃強度が低下し、表面外観不良、微細な平均セル径なセルではない、セル数が少ない等の点で好ましくなく、本発明で意図する発泡体は製造不可能であった。
【０１０７】
実施例８〜１０
実施例３と同一の射出成形機に８０×８０×６（厚み）ｍｍの大きさのシートが成形出来る金型（８）を取り付けた。厚みはコアバック量により６ｍｍ〜１５ｍｍに調整できる様にした。成形材料として実施例３と同等のポリスチレンを用い、二酸化炭素の注入量を８重量部とした以外は実施例３と同等とした。得られたシートの比重、ＳＥＭ写真観察により無発泡のスキン層厚み、発泡層の平均セル径、セル密度を測定し、高速衝撃試験機（Ｒｈｅｏｍｅｔｒｉｃｓ社製 ＲＩＴ８０００）により面衝撃強さ（破壊エネルギー）を０℃、撃芯径１／２インチ、受け台径 ２インチ、撃芯速度 １０ｍ／ｓｅｃで測定した。結果を表２に示す。厚みが厚いものでも平均セル径は小さかった。
【０１０８】
実施例１１〜１２
実施例８〜１０において、８０×８０×１５（厚み）ｍｍの大きさのシートが成形出来る金型（８）を取り付け、コアバック量により厚みを２０ｍｍ〜５０ｍｍに調整できる様にした以外は実施例８〜１０に従い発泡シートを得た。結果を表２に示す。厚みが厚いものでも平均セル径は小さかった。
【０１０９】
比較例４〜８
第一押し出し機（スクリュウ径５０ｍｍ，Ｌ／Ｄ ２５ シリンダー温度１８０〜２２０℃）（１７）と第二押し出し機（スクリュウ径６５ｍｍ，Ｌ／Ｄ＝３８シリンダー温度 １５０℃）（１８）よりなるタンデム型押し出し機に図６に示す押し出しダイス及び冷却装置（１９）を取り付けダイス温度１４０とし、第一押し出し機のスクリュウ先端から４００ｍｍの所から二酸化炭素を８重量部注入し発泡シート（２０）を得た。リップ開度と押し出し量、ダイス内圧を調整し厚み６〜１５ｍｍのシートを得た。実施例８と同様に比重、平均セル径、セル密度、面衝撃強さを測定した。結果を表２に示す。射出成形方法による実施例８〜１２に比べて厚みが厚いほど平均セル径が大きかった。また、面衝撃強さも実施例８〜１２に比べて低かった。また図８に示す様に、発泡押出成形で得られた発泡シートの表層は、内層部と同じ様に発泡しており緻密な非発泡層は存在しなかった。
【０１１０】
実施例１３
２００℃、５kgにおけるメルトフローインデックスが２．６g／10分であるポリスチレン樹脂（三井東圧化学（株）製、トーポレックス５５５−５７）のペレット１００重量部に、ポリジメチルシロキサン１重量部をドライブレンドしたのち、該混合物をホッパー（９）より口径３０mm、Ｌ／Ｄ＝３０のスクリュウ（１２）を持つ連続可塑化装置（１）中に供給し、２３０℃で加熱溶融し、昇圧ポンプ（１１）により１８０kg/cm2に昇圧し超臨界状態とした二酸化炭素１５重量部を、該樹脂が完全に溶融したところに供給した。連続可塑化装置（１）中で二酸化炭素と溶融樹脂を混練溶解させ、溶融樹脂組成物の樹脂温度を徐々に１５０℃に冷却し、１５０℃に設定した射出装置（７）へ計量後、５０℃に設定した金型（８）内に射出した。このとき、射出される直前の金型（８）内には、窒素ガスを８０kg/cm2の圧力下で充填させておいた。射出終了後、金型（８）内に充填させた窒素ガスを１秒間で抜き、さらに金型（８）のコアを２mm後退させることで、樹脂発泡成形体である引張試験用ダンベル片（試験片厚み４mm）を得た。この間、金型（８）内での冷却時間を３０秒として連続的に成形したが離型後に発泡体の表面が二次発泡により不良になることは皆無であった。
【０１１１】
発泡体の評価の結果を表３に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【０１１２】
実施例１４
実施例１３において、ポリスチレン樹脂とポリジメチルシロキサンの他に平均粒子径２μmのタルク２重量部を添加した以外は、実施例１３に従い発泡体を得た。
【０１１３】
発泡体の評価の結果を表３に示す。アイゾット衝撃強度が向上し、表面外観良好、微細な平均セル径で均一な平均セル密度のセルを有する発泡体であった。
【０１１４】
実施例１５〜１８
実施例１３において、ポリスチレン樹脂とポリジメチルシロキサンおよび二酸化炭素の割合を表３に示した割合とした以外は、実施例１３に従い発泡体を得た。発泡体の評価の結果を表３に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【０１１５】
実施例１９
実施例１３において、ポリスチレン樹脂を２００℃、５kgにおけるメルトフローインデックスが１０g／10分であるポリスチレン樹脂（三井東圧化学（株）製、トーポレックス５２５−５１）とした以外は、実施例１３に従い発泡体を得た。発泡体の評価の結果を表３に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【０１１６】
実施例２０
実施例１３において、ポリスチレン樹脂を２００℃、５kgにおけるメルトフローインデックスが１．８g／10分であるポリスチレン樹脂（三井東圧化学（株）製、トーポレックス５７５−５７）とした以外は、実施例１３に従い発泡体を得た。発泡体の評価の結果を表３に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【０１１７】
比較例９〜１１
実施例１３において、ポリスチレン樹脂、ポリジメチルシロキサンおよび二酸化炭素の割合を表３に示した割合とした以外は、実施例１３に従い発泡体を得た。
発泡体の評価の結果を表３に示す。表面外観不良、微細な平均セル径なセルではない、セル数が少ない等の点で好ましくなく、本発明で意図する発泡体は製造不可能であった。
【０１１８】
実施例２１
２００℃、５kgにおけるメルトフローインデックスが２．６g／10分であるポリスチレン樹脂（三井東圧化学（株）製、トーポレックス５５５−５７）のペレット１００重量部に、モンタン酸パーフルオロプロピルエステル１重量部をドライブレンドしたのち、該混合物をホッパー（９）より口径３０mm、Ｌ／Ｄ＝３０のスクリュウ（１２）を持つ連続可塑化装置（１）中に供給し、２３０℃で加熱溶融し、昇圧ポンプ（１１）により１８０kg/cm2に昇圧し超臨界状態とした二酸化炭素１５重量部を、該樹脂が完全に溶融したところに供給した。連続可塑化装置（１）中で二酸化炭素と溶融樹脂を混練溶解させ、溶融樹脂組成物の樹脂温度を徐々に１５０℃に冷却し、１５０℃に設定した射出装置（７）へ計量後、５０℃に設定した金型（８）内に射出した。このとき、射出される直前の金型（８）内には、窒素ガスを８０kg/cm2の圧力下で充填させておいた。射出終了後、金型（８）内に充填させた窒素ガスを１秒間で抜き、さらに金型（８）のコアを２mm後退させることで、樹脂発泡成形体である引張試験用ダンベル片（試験片厚み４mm）を得た。この間、金型（８）内での冷却時間を３０秒として連続的に成形したが離型後に発泡体の表面が二次発泡により不良になることは皆無であった。
【０１１９】
発泡体の評価の結果を表４に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【０１２０】
実施例２２
実施例２１において、ポリスチレン樹脂とモンタン酸パーフルオロプロピルエステルの他に平均粒子径２μmのタルク２重量部を添加した以外は、実施例２１に従い発泡体を得た。
【０１２１】
発泡体の評価の結果を表４に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【０１２２】
実施例２３〜２６
実施例２１において、ポリスチレン樹脂とモンタン酸パーフルオロプロピルエステルおよび二酸化炭素の割合を表４に示した割合とした以外は、実施例２１に従い発泡体を得た。発泡体の評価の結果を表４に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【０１２３】
実施例２７
実施例２１において、ポリスチレン樹脂を２００℃、５kgにおけるメルトフローインデックスが１０g／10分であるポリスチレン樹脂（三井東圧化学（株）製、トーポレックス５２５−５１）とした以外は、実施例２１に従い発泡体を得た。発泡体の評価の結果を表４に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【０１２４】
実施例２８
実施例２１において、ポリスチレン樹脂を２００℃、５kgにおけるメルトフローインデックスが１．８g／10分であるポリスチレン樹脂（三井東圧化学（株）製、トーポレックス５７５−５７）とした以外は、実施例２１に従い発泡体を得た。発泡体の評価の結果を表４に示す。アイゾット衝撃強度が向上し、表面外観良好、中間層に微細な平均セル径で均一な平均セル密度のセルを有する発泡部分と、表層に発泡部分と一体化した非発泡部分を有する発泡体であった。
【０１２５】
比較例１２〜１４
実施例２１において、ポリスチレン樹脂、モンタン酸パーフルオロプロピルエステルおよび二酸化炭素の割合を表４に示した割合とした以外は、実施例２１に従い発泡体を得た。
【０１２６】
発泡体の評価の結果を表４に示す。アイゾット衝撃強度が低下し、表面外観不良、微細な平均セル径なセルではない、セル数が少ない等の点で好ましくなく、本発明で意図する発泡体は製造不可能であった。
【０１２７】
【表１】

Figure 0004144916
【０１２８】
【表２】
Figure 0004144916
【０１２９】
【表３】
Figure 0004144916
【０１３０】
【表４】
Figure 0004144916
【０１３１】
【発明の効果】
本発明の熱可塑性樹脂発泡射出成形体の製造方法により製造される成形体は表面外観が良好で一体化した非発泡部分を表層に有し、微細な平均セル径で均一な平均セル密度のセルを有する。
【図面の簡単な説明】
【図１】本発明の熱可塑性樹脂発泡射出成形体の製造方法の一例を示す概略構成図である。
【図２】本発明の熱可塑性樹脂発泡射出成形体の製造方法の一例を示す概略構成図である。
【図３】本発明の熱可塑性樹脂発泡射出成形体の製造方法の一例を示す概略構成図である。
【図４】本発明の熱可塑性樹脂発泡射出成形体の製造方法の一例を示す概略構成図である。
【図５】通常の押出機を用いた熱可塑性樹脂発泡体の製造方法（比較例３）を示す概略構成図である。
【図６】押出成形による熱可塑性樹脂発泡体の製造方法（比較例４〜６）を示す概略構成図である。
【図７】本発明の熱可塑性樹脂発泡射出成形体の断面の一例。
【図８】発泡押出成形により製造される熱可塑性樹脂発泡体の断面の一例である。
【符号の説明】
（１） 連続可塑化装置
（２） アダプター
（３） 樹脂アキュームレータプランジャー
（４） 樹脂アキュームレータ装置
（５） 開閉バルブ
（６） 射出プランジャー
（７） 射出装置
（８） 金型
（９） ホッパー
（１０）ガスボンベ
（１１）昇圧ポンプ
（１２）スクリュウ
（１３）ガスボンベ
（１４）圧力制御バルブ
（１５）開閉バルブ
（１６）インライン式射出成形機
（１７）第一押出機
（１８）第二押出機
（１９）冷却装置
（２０）熱可塑性樹脂発泡体[0001]
BACKGROUND OF THE INVENTION
  The present invention has excellent physical properties and surface appearance.Method for producing thermoplastic resin foam injection molded articleAnd more particularly as a blowing agentSupercriticalA foamed portion having cells with fine average cell diameter and uniform average cell density using carbon dioxide and / or nitrogen, and its surface has a good appearance and integrated with the foamed portion.Non-foamed partThe present invention relates to a method for producing a thermoplastic resin foam injection-molded article.
[0002]
[Prior art]
A method for producing a thermoplastic resin foam using a chemical foaming agent or a physical foaming agent is known.
[0003]
The chemical foaming method is a method in which foam molding is generally performed by mixing a raw material resin and a low molecular weight organic foaming agent that decomposes at a molding temperature to generate a gas and heating it to a temperature higher than the decomposition temperature of the foaming agent. In this method, gas generation is sharp with respect to the decomposition temperature, and the decomposition temperature can be easily adjusted by adding a foaming aid or the like, and a foam having closed cells can be obtained.
[0004]
However, these foams are expensive because of the use of a special foaming agent, and because of the decomposition residue of the foaming agent remaining in the foam, discoloration of the foam, generation of odor, food It causes hygiene problems. In addition, there is a problem with the molding machine contamination caused by the chemical foaming agent and the molding failure associated therewith.
[0005]
On the other hand, the gas foaming method, which is a physical foaming method, supplies a low-boiling organic compound such as butane, pentane or dichlorodifluoromethane to the melted resin with a molding machine, kneads, and then presses the low-pressure region. This is a method of foam molding by releasing the resin. The low boiling point organic compound used in this method has a characteristic of being able to obtain a high-magnification foam because it has an affinity for the resin and thus has excellent solubility and excellent retention. ing. However, these foaming agents are not only expensive, but also have dangers such as flammability and toxicity, and may cause air pollution problems. In addition, chlorodifluoromethane and other chlorofluorocarbon gases are being abolished due to environmental problems of ozone layer destruction.
[0006]
In order to solve such problems of the conventional method, many methods have been proposed in which an inert gas such as carbon dioxide and nitrogen that is clean and inexpensive is used as a blowing agent. However, since the inert gas has low affinity with the resin, it has poor solubility. For this reason, since the foam has a large cell diameter, non-uniformity, and a low cell density, there are problems in appearance, mechanical strength, heat insulating properties, and expansion ratio.
[0007]
Various methods have been proposed so far in injection foam molding for molding structural foam. The foams obtained by these methods form a sandwich structure consisting of a skin layer on the surface and an intermediate core layer. 3 to 4 times more rigid. However, since the cell diameter of the foam produced by these methods is as large as 50 to 100 μm and the cell diameter is not uniform, the cell may be a starting point of fracture in the impact strength test, which is accompanied by a decrease in strength. It has been pointed out.
[0008]
As a technique for solving these problems, U.S. Pat. No. 4,473,665 describes a manufacturing method for obtaining a foamed molded product in which fine cells having a diameter of 2 to 25 μm are uniformly dispersed. In this method, first, under pressure, an inert gas is impregnated in a thermoplastic resin sheet until it is saturated. Thereafter, the cell growth is controlled by heating to the glass transition temperature of the thermoplastic resin and then reducing the pressure to bring the gas impregnated into the resin into a supersaturated state, generating cell nuclei and quenching. Alternatively, a method was used in which a thermoplastic resin saturated with an inert gas under pressure was heated and melted and shaped under pressure, then cooled and decompressed to generate cell nuclei and cooled to control the cell diameter. Exemplified are manufacturing methods by extrusion and injection molding. By the above method, a fine foam having a large number of cells can be obtained. However, since the inert gas has low affinity with the resin, it takes more than 10 hours to completely impregnate the resin with the gas. It is substantially difficult to implement industrially.
[0009]
US Pat. No. 5,158,986 describes a technique for obtaining a foam having an extremely fine cell diameter and a large cell density by using a supercritical fluid as a foaming agent and impregnating it with a thermoplastic resin. Supercritical liquid has excellent solubility close to liquid and excellent diffusibility close to gas, so it has high solubility in the resin and has a high diffusion rate in the resin. The resin can be impregnated. In this publication, a thermoplastic resin is made into a sheet by an extruder, introduced into a pressure chamber filled with supercritical carbon dioxide, impregnated with carbon dioxide in the sheet, and then heated in a foaming chamber under atmospheric pressure. The foam is heated and foamed to obtain a foam, and the resin melted with an extruder is impregnated with supercritical carbon dioxide, and the extruded product is introduced into a pressure chamber and the pressure change A method has been proposed in which cell nuclei are generated by heating, and the cell diameter and cell density are controlled by heating and cooling to obtain a foam.
[0010]
However, both methods require large-scale high-pressure equipment, enormous equipment costs, poor work efficiency, and are difficult to industrialize. Further, since the former method impregnates the sheet-shaped molded body directly, it takes a long time to completely infiltrate the carbon dioxide into the molded body, and the latter method impregnates the molten resin in the former method. Although the carbon dioxide permeation rate is faster than the method, it is difficult to compatibilize carbon dioxide and generate a large number of cell nuclei by only kneading one extruder, and a fine foam having a large number of cells is obtained. It was difficult.
[0011]
In JP-A-8-11190, the present inventors impregnate a molten thermoplastic resin with an inert gas as a foaming agent by using an adapter having a first extruder and a mixing section connected thereto, and the thermoplastic resin. And a gas dissolving step for forming a compatible state of inert gas, a cooling step for lowering the temperature of the molten resin while maintaining a pressurized state by a second extruder, and a large number of cell nuclei by rapid pressure drop A manufacturing method by foam extrusion molding of a thermoplastic resin foam having uniformly a large number of cells, which is characterized by comprising a nucleation step to be generated and a foam control step for controlling the cell diameter, has been proposed.
[0012]
In this production method, it is possible to continuously produce a foam which is substantially difficult by the production methods described in US Pat. No. 4,473,665 and US Pat. No. 5,158,986. However, this manufacturing method requires a very narrow die lip opening in order to give high shear to the molten resin in the nucleation process, which is suitable for manufacturing a thin foam, but a relatively thick foam. It is becoming clear that it is not suitable for manufacturing the body. JP-A-8-11190 only discloses an extrusion molding method.
[0013]
In US Pat. No. 5,158,986, after a thermoplastic resin is melted and impregnated with supercritical carbon dioxide in an injection molding machine cylinder, it is heated rapidly when dispersed uniformly to produce cell nuclei, and foaming is performed. In order to control, a method has been proposed in which a foam is obtained by injecting a molten resin into a mold filled with a high-pressure gas.
[0014]
However, in this method
1) In order to perform resin melting, carbon dioxide kneading and injection only with an injection molding machine, and to stop the measurement of resin during injection, ensuring the quantitativeness of the continuously supplied carbon dioxide supply and It is difficult to keep the mixing ratio of the thermoplastic resin and carbon dioxide constant.
2) With only a normal injection molding machine, the screw back pressure stops after the completion of measurement, so that the compatible thermoplastic resin and carbon dioxide are separated, and it is difficult to make the cell finer when injected into the mold. .
As a result, in the case of a molded product as small as a test piece for measuring physical properties, a fine cell foam can be obtained, but in the case of a large molded product, it is difficult to obtain a uniform and fine cell diameter. There was a problem such as.
[0015]
[Problems to be solved by the invention]
  The object of the present invention is to use carbon dioxide and / or nitrogen as a foaming agent, and have a foamed portion having fine average cell diameter and cells having a uniform average cell density and a good surface appearance, and integrated with the foamed portion on the surface layer. didNon-foamed partHaveMethod for producing thermoplastic resin foam injection molded articleIs to provide.
[0016]
[Means for Solving the Problems]
  The inventors of the present invention have a foamed portion having cells with a fine average cell diameter and a uniform average cell density, and a surface appearance is good and is integrated with the foamed portion on the surface layer.Non-foamed partAs a result of diligent research on a thermoplastic resin foam injection molded article having a flow rate, an injection apparatus (7) having an injection plunger (6) is connected to a continuous plasticizing apparatus (1) having a line for supplying a foaming agent. With thermoplastic resinSupercritical carbon dioxide and / or nitrogenAfter thoroughly blending and making them compatible, a thermoplastic resin foam that has a non-foamed portion on the surface layer that has a rapid pressure drop and is continuous and has a good surface appearance and is integrated with the foamed portion in a short time. The inventors have found that an injection-molded article can be produced and have reached the present invention. That is, the present invention includes the following embodiments.
[0019]
  (A)The inner layer has an average cell diameter of 0.01 to 50 μm and an average cell density of 10 8 -10 16 Piece / cm Three And a method for producing a thermoplastic resin foam injection-molded article having a foamed part and a non-foamed part having a thickness of 10 to 1000 μm integrated with the foamed part on a surface layer,
(I) In a continuous plasticizer (1) having a line for supplying a foaming agent, 100 parts by weight of a thermoplastic resin is melted at 100 to 450 ° C., and carbon dioxide and / or nitrogen in a supercritical state is thermoplasticized. 0.1 to 30 parts by weight per 100 parts by weight of resin, a gas that continues quantitative mixing and dissolution of the thermoplastic resin and carbon dioxide and / or nitrogen in a supercritical state to form a molten resin composition in a compatible state Dissolution process,
(II) a cooling step of lowering the molten resin composition to a temperature of 50 to 300 ° C. while maintaining a pressure equal to or higher than the critical pressure of carbon dioxide and / or nitrogen in the continuous plasticizer (1);
(III) By an injection device (7) having an injection plunger (6) connected to a continuous plasticizer (1),While maintaining the pressure above the critical pressure of carbon dioxide and / or nitrogenA metering and injection step of weighing the cooled molten resin composition and filling the mold (8); and
(IV) comprising a foam control step of generating cell nuclei by controlling the pressure in the mold (8) to a pressure lower than the critical pressure of the carbon dioxide and / or nitrogen, and controlling the cell diameter; Until the injection process, the supercritical state of carbon dioxide and / or nitrogen is maintained, and the gas dissolution process by the continuous plasticizer (1) and the cooling process and the metering injection process by the injection apparatus (7) are performed independently.CharacterizeA method of producing a thermoplastic resin foam injection molded article.
[0020]
  (b) Between the continuous plasticizer (1) having a line for supplying a foaming agent and the injection device (7) having an injection plunger (6), an injection device (7) via an on-off valve (5)Connected toThe method for producing a thermoplastic resin foam injection-molded article according to (a), wherein an adapter (2) having a mixing part connected to the outflow passage of the continuous plasticizer (1) is provided.
[0021]
  (C)  A foam with a thickness of 0.5-50mm can be manufactured.(A)The manufacturing method of the thermoplastic resin foam injection molding of description.
[0022]
  (D)  A foam with a thickness of 10 to 50 mm can be manufactured.(A)The manufacturing method of the thermoplastic resin foam injection molding of description.
[0023]
  (E)The foaming control step is performed by degassing the high pressure gas filled in the mold (8) after injecting the molten resin composition and / or the core of the mold (8).at leastWith some retreat(A)The manufacturing method of the thermoplastic resin foam injection molding of description.
[0024]
  (F)0.1 to 10 parts by weight of a foam stabilizer is further added to the thermoplastic resin.(A)The manufacturing method of the thermoplastic resin foam injection molding of description.
[0025]
  (g) Between the continuous plasticizer (1) having a line for supplying a foaming agent and the injection device (7) having an injection plunger (6), an injection device (7) via an on-off valve (5)Connected toA method for producing a thermoplastic resin foam injection molded article according to (a), wherein a resin accumulator device (4) having a plunger is provided.
[0026]
  (h) Between the adapter (2) having the mixing portion and the injection device (7) having the injection plunger (6), the injection device (7) is connected via the open / close valve (5).Connected toA method for producing a thermoplastic resin foam injection molded article according to (g), wherein a resin accumulator device (4) having a plunger is provided.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
The present inventors have studied to achieve the above object. The apparatus and method of FIG. 1 designed for the present invention will be described. An injection device (7) having an injection plunger (6) was connected to a continuous plasticizing device (1) having a line for supplying a blowing agent via an on-off valve (5). The resin is transferred to the continuous plasticizer (1), and carbon dioxide and / or nitrogen in a supercritical state is introduced while being heated and melted to form a molten resin composition in a compatible state.
[0028]
Thereafter, the molten resin composition is transferred to an injection device (7) having an injection plunger (6). After the transfer, the open / close valve (5) is closed, whereby the continuous plasticizing device (1) and the injection device (7) become independent from each other. The continuous plasticizing device (1) continuously forms a molten resin composition without stopping while the injection device (7) is performing metering injection. During this period, the pressure in the continuous plasticizing device (1) rises because no measurement is performed on the injection device (7), but the compatibility state of the molten resin composition is not broken by the increase in pressure, so the gas dissolving step There is no problem in continuing the cooling process. However, when a problem arises in the pressure resistance of the continuous plasticizing device (1), it is possible to set the device so that the molten resin composition can be discharged out of the system by operating the on-off valve (5). .
[0029]
On the other hand, the injection device (7) performs injection after the end of the metering. In the normal injection molding machine shown in FIG. 5, the back pressure is temporarily cut after the end of the metering. Maintain a constant back pressure above the critical pressure of the agent. For this reason, the molten resin composition formed by the continuous plasticizer (1) is injected into the mold (8) without phase separation of the foaming agent and the resin.
[0030]
  In the mold (8), after injecting the molten resin composition, the high pressure gas filled in the mold (8) is degassed and / or a part or all of the mold (8) core is retracted. A foam control process is performed. The portion in contact with the resin mold (8) injected at this time is cooled and is dense so that substantially no cells of 1 μm or more exist.Non-foamed layerAs a result, the cross section of the foam injection molded product has a structure as shown in FIG.
[0031]
One embodiment of the present invention is shown in FIG. The continuous plasticizer (1) having a line for supplying a foaming agent and the injection device (7) having an injection plunger (6) are connected to the injection device (7) via an open / close valve (5). Providing the adapter (2) having a mixing part connected to the outflow passage of the continuous plasticizing apparatus (1) further promotes mixing of the molten thermoplastic resin and carbon dioxide and / or nitrogen, and is thermoplastic. It becomes easy to form a compatible state of the resin and carbon dioxide and / or nitrogen, and the temperature of the adapter (2) is controlled so that the resin in the molten state has a viscosity suitable for the subsequent injection and foaming. It becomes easy to cool. Although there is no restriction | limiting in particular about the adapter (2) which has this mixing part, Since the kneading | mixing and cooling of resin are performed, the adapter (2) which incorporates a static mixer is used suitably.
[0032]
One embodiment of the present invention is shown in FIG. By providing a resin accumulator device (4) having a plunger connected to the injection device (7) via an opening / closing valve (5) before the injection device (7) having an injection plunger (6), After the completion of the measurement, the opening / closing valve (5) is switched to the closed state, and the melt sent from the continuous plasticizer (1) while being injected into the mold (8) by the injection plunger (6). The resin is sent to a resin accumulator device (4) provided immediately before the opening / closing valve (5), and the plunger of the resin accumulator device (4) is retracted by the inflow of the molten resin. The control in (4) makes it easy to maintain the inside of the apparatus system at a predetermined pressure, so that it is easy to maintain the compatible state of the molten resin composition, and the cell diameter of the foamed injection molded article is made fine. Preferable because it becomes easy.
[0033]
One embodiment of the present invention is shown in FIG. Furthermore, it is also possible to provide an injection device (7) having another injection plunger (6) instead of the resin accumulator device (4) having a plunger, and maintain the inside of the device system at a predetermined pressure. Therefore, it is easy to maintain a compatible state of the molten resin composition, and it is easy to make the cell diameter of the foamed injection-molded article finer, which is preferable.
[0034]
As the thermoplastic resin used in the present invention, any thermoplastic resin having a plasticizing temperature of 100 to 450 ° C. can be used without particular limitation. For example, a styrene resin (for example, polystyrene, butadiene / styrene copolymer, Acrylonitrile / styrene copolymer, acrylonitrile / butadiene / styrene copolymer, etc.), ABS resin, polyethylene, polypropylene, ethylene-propylene resin, ethylene-ethyl acrylate resin, polyvinyl chloride, polyvinylidene chloride, polybutene, polycarbonate, polyacetal, Polyphenylene oxide, polyvinyl alcohol, polymethyl methacrylate, saturated polyester resin (for example, polyethylene terephthalate, polybutylene terephthalate, etc.), biodegradable polyester resin (for example, poly milk Hydroxycarboxylic acid condensates such as, condensates of diol and dicarboxylic acid such as polybutylene succinate, etc.) Polyamide resin, polyimide resin, fluororesin, polysulfone, polyethersulfone, polyarylate, polyetheretherketone, liquid crystal Examples thereof include one or a mixture of two or more of polymers. Among these thermoplastic resins, styrene resins and polyolefin resins are preferable, and polystyrene and polypropylene are particularly preferable.
[0035]
Furthermore, the melt flow index measured around the processing temperature of each thermoplastic resin is 0.05 to 60 g / 10 minutes, preferably 0.1 to 40 g / 10 minutes, more preferably about 0.2 to 20 g / 10 minutes. It is preferable that it exists in the range. The measurement conditions in this case, that is, the measurement temperature and load are the conditions specified by ASTM, for example, in the case of polypropylene, 230 ° C., 2.16 kgf / cm.2In the case of polystyrene, 200 ° C, 5.0kgf / cm2In addition, the measurement is performed in accordance with measurement conditions defined in ASTM D1238.
[0036]
When the melt flow index is above the lower limit range, the resin viscosity at the time of melting is appropriate, the load on the extruder is not excessive, and processing is easy. Moreover, if it is below the said upper limit range, resin can endure the gas pressure at the time of foaming, can hold | maintain a viscosity, and can produce | generate a micro cell without producing a bubble breakage. The melt index of the resin to be used can be appropriately selected according to this guideline.
[0037]
For example, when a thermoplastic resin having a melt flow index of 10 to 60 g / 10 min, such as polypropylene or polystyrene, is used, a product with a high magnification is easily obtained. Also, when a melt flow index of 0.05 to 10 g / 10 min is used, the cooling time can be shortened because of rapid cooling and solidification, resulting in an improvement in productivity.
[0038]
The amount of carbon dioxide and / or nitrogen in the supercritical state used as a blowing agent in the present invention is 0.1 to 30 parts by weight, more preferably 0.2 to 20 parts per 100 parts by weight of the thermoplastic resin composition. It is preferable that it is a weight part.
[0039]
When the foaming agent is 0.1 parts by weight or less, a fine average cell diameter cannot be obtained. When the foaming agent is 30 parts by weight or more, a blistering appearance defect occurs on the foam surface, and a beautiful surface appearance is difficult to obtain.
[0040]
Carbon dioxide or nitrogen in a supercritical state used as a blowing agent can be used alone, but carbon dioxide and nitrogen may be mixed and used. In this case, the mixing ratio is preferably in the range of 1: 9 to 9: 1 in terms of molar ratio. If the thermoplastic resin used in the foam is a polyester resin such as PET, PBT, or polylactic acid, polycarbonate, polyamide, etc., the one that uses carbon dioxide and nitrogen together rather than using carbon dioxide alone as the foaming agent However, it is preferable because cell miniaturization and high cell density are facilitated.
[0041]
Examples of the method of mixing the foaming agent in the melt of the resin composition in the injection molding machine include a method of injecting carbon dioxide and / or nitrogen in a gaseous state directly or under pressure, carbon dioxide in a liquid state and / or A method of injecting nitrogen with a plunger pump or the like can be mentioned.
[0042]
These carbon dioxide and / or nitrogen need to be in a supercritical state inside the molding machine from the viewpoint of solubility in the molten resin composition, permeability, diffusibility, and the like.
[0043]
In the present invention, a pyrolytic foaming agent that generates carbon dioxide or nitrogen by thermal decomposition can also be used as a foam nucleating agent. Examples thereof include azodicarbonamide, N, N-dinitrosopentatetramine, azo Examples thereof include bisisobutyronitrile, citric acid, and sodium bicarbonate.
[0044]
In order to make the cell diameter fine, one or more kinds of various foam stabilizers can be added to the thermoplastic resin used in the present invention, and the foam stabilizer is used in ordinary foam molding. For example, organopolysiloxanes or fluoroalkane esters of aliphatic carboxylic acids are preferably used.
[0045]
Organopolysiloxanes include polydimethylsiloxane, polydiphenylsiloxane, polymethylphenylsiloxane, polymethylhydrogensiloxane, and modified organopolysiloxanes modified with epoxy group-containing compounds, amino group-containing compounds, ester bond-containing compounds, etc. Polysiloxane etc. are mentioned. Of these, polydimethylsiloxane is preferred from the viewpoints of dispersibility in the resin, solubility, and the effect of improving the surface appearance.
[0046]
When the modified organopolysiloxane is used, the compatibility with the resin can be improved by adding a radical generator such as peroxide.
[0047]
The fluoroalkane ester of an aliphatic carboxylic acid is a fluoroalkane ester having a fluoroalkane group derived from an aliphatic carboxylic acid having 3 to 30 carbon atoms and an alkyl group having 3 to 30 carbon atoms. As, for example, lauric acid, stearic acid, crotonic acid, oleic acid, maleic acid, glutaric acid, montanic acid and the like are suitable, from the viewpoint of dispersibility in resin, solubility, surface appearance improvement effect, etc. A fluoroalkane ester of montanic acid is preferred, and a perfluoroalkane ester of montanic acid is particularly preferred.
[0048]
The amount of these foam stabilizers added is 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, more preferably 0.3 to 5 parts by weight, based on the thermoplastic resin.
[0049]
When the addition amount of the foam stabilizer is 0.1% by weight or more, cell miniaturization of the foam is easy, and when it is 10 parts by weight or less, the resin can maintain a viscosity sufficient to withstand the gas pressure at the time of foaming. Fine cells can be generated without generating bubbles.
[0050]
In the present invention, an inorganic fine powder that acts as a foam nucleating agent can be used as an additive of the thermoplastic resin composition. Examples of the inorganic fine powder include talc, calcium carbonate, clay, magnesium oxide, zinc oxide, glass beads, glass powder, titanium oxide, carbon black, anhydrous silica, etc., preferably talc, calcium carbonate, oxidized Titanium and anhydrous silica are preferable, and talc is particularly preferable. The particle size is preferably 50 μm or less, more preferably 10 μm or less, and particularly preferably 5 μm or less.
[0051]
The resin composition includes ethylene-propylene rubber, ethylene-butene rubber, propylene-butene rubber, styrene, in addition to the inorganic fine powder, aliphatic carboxylic acid and derivatives thereof exemplified in the composition, as long as the characteristics of the present invention are not impaired. -Hydrogenated butadiene diblock copolymer, hydrogenated styrene-butadiene-styrene triblock copolymer, hydrogenated styrene-isoprene block copolymer, styrene-isoprene-styrene triblock copolymer Hydrogenated products, low-density polyethylene, high-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, polybutene and other elastomers, plasticizers, For purposes such as pigments, stabilizers, fillers, metal powders, etc. It is possible to suitably use according to.
[0052]
There is no restriction | limiting in particular about the manufacturing method of the thermoplastic resin composition used as the raw material of the thermoplastic resin foam injection molding of this invention, Usually a well-known method is employable. For example, a thermoplastic resin and, if necessary, additives such as organopolysiloxane or fluoroalkane ester of aliphatic carboxylic acid are uniformly mixed with a high-speed stirrer, etc., and then a uniaxial or multiaxial extruder with sufficient kneading ability, mixing It can be produced by a melt kneading method using a roll, a kneader, a Brabender, or the like. Further, it is possible to use the thermoplastic resin and organopolysiloxane, aliphatic carboxylic acid fluoroalkane ester or the like in a uniformly mixed state.
[0053]
The gas dissolving step for forming a compatible state of the thermoplastic resin composition and carbon dioxide and / or nitrogen in the present invention is a continuous plastic in the example of the method for producing a thermoplastic resin foam injection molded article shown in FIG. After the resin composition is heated and melted in the gasification apparatus (1), supercritical carbon dioxide and / or nitrogen is added to the molten resin composition and mixed uniformly. The cooling step is In this process, the resin composition in a molten state is cooled and adjusted to have a viscosity suitable for injection and foaming.
[0054]
The gas dissolving step and the cooling step are performed by the continuous plasticizing apparatus (1) and the adapter (2) in the example of the method for producing the thermoplastic resin foam injection molded article shown in FIG. Moreover, in the example of the manufacturing method of the thermoplastic resin foam injection molding shown in FIG. 3, it performs with the continuous plasticizer (1), the adapter (2), and the resin accumulator apparatus (4).
[0055]
The metering injection process is a process in which a temperature-controlled resin composition is measured in an injection device (7) so as to have a viscosity suitable for injection and foaming, and injection is performed with the injection plunger (6). The control step is a step of reducing the pressure of the resin composition injected into the mold (8) from under pressure, generating cell nuclei, and controlling the cell diameter. Among these, at least the gas dissolving step and the cooling step are performed as follows in accordance with the method described in the claims and examples of JP-A-8-11190.
[0056]
A thermoplastic resin is supplied from the hopper (9) into the continuous plasticizer (1) and melted by heating at 100 to 450 ° C. Carbon dioxide and / or nitrogen is transported from the gas cylinder (10) to the booster pump (11) where the pressure is increased and the pressure-controlled carbon dioxide and / or nitrogen is melted in the continuous plasticizer (1). Supplied in the composition. At this time, carbon dioxide and / or nitrogen present in the continuous plasticizer (1) greatly enhances the solution diffusion to the resin composition, and can penetrate into the resin composition in a short time. The system is maintained at or above the critical pressure and critical temperature of the carbon dioxide and / or nitrogen. Further, the carbon dioxide and / or nitrogen supplied into the continuous plasticizing apparatus (1) is heated and pressurized to be in a supercritical state, or is heated and pressurized before being supplied to the continuous plasticizing apparatus (1). And supplied after reaching a supercritical state.
[0057]
In the continuous plasticizer (1), the molten resin composition and carbon dioxide and / or nitrogen are kneaded by the screw (12) to form a compatible state of the thermoplastic resin composition and carbon dioxide and / or nitrogen. In the cooling step after compatibilization, the temperature of the tip of the continuous plasticizer (1) is controlled so that the resin composition in the molten state is 50 to 300 ° C., preferably 80 to 280 ° C. and above the plasticizing temperature of the molten resin composition. Cool and adjust to a viscosity suitable for subsequent injection and foaming.
[0058]
First to fourth embodiments of the present invention will be described below with reference to the drawings. 1-4, (1) is a continuous plasticizer, (2) is an adapter, (3) is a resin accumulator plunger, (4) is a resin accumulator device, (5) is an open / close valve, and (6) is injection Plunger, (7) Injection device, (8) Mold, (9) Hopper, (10) Gas cylinder, (11) Booster pump, (12) Screw, (13) Gas cylinder, (14 ) Is a pressure control valve, and (15) is an open / close valve.
[0059]
In FIG. 1, in the gas dissolving step, 100 parts by weight of a thermoplastic resin is supplied from the hopper (9) into the continuous plasticizer (1) and melted by heating. Carbon dioxide and / or nitrogen is transported from the gas cylinder (10) to the booster pump (11) where the pressure is increased and 0.1-30 parts by weight of carbon dioxide and / or nitrogen whose pressure is controlled is a continuous plasticizer. (1) It is supplied into the molten resin composition in and the gas dissolution step is performed. At this time, carbon dioxide and / or nitrogen present in the continuous plasticizer (1) greatly enhances the solution diffusion to the resin composition, and can penetrate into the resin composition in a short time. The inside of the system needs to be maintained above the critical pressure and critical temperature of the carbon dioxide and / or nitrogen. For example, in the case of carbon dioxide, the critical pressure is 75.3 kg / cm.2The critical temperature is 31.35 ° C., and in the case of nitrogen, the critical pressure is 33.5 kg / cm2The critical temperature is -147.0 ° C., and the pressure in the continuous plasticizer (1) is 75 to 400 kg / cm.2, Preferably 100-300kg / cm2The temperature and the temperature are from 100 to 450 ° C, preferably from 110 to 280 ° C.
[0060]
Further, the carbon dioxide and / or nitrogen supplied into the continuous plasticizing apparatus (1) is heated and pressurized to be in a supercritical state, or is heated and pressurized before being supplied to the continuous plasticizing apparatus (1). In addition, it may be supplied after reaching a supercritical state.
[0061]
In the continuous plasticizer (1), the molten resin composition and carbon dioxide and / or nitrogen are kneaded by the screw (12) to form a compatible state of the thermoplastic resin composition and carbon dioxide and / or nitrogen. In the cooling step after compatibilization, the temperature of the tip of the continuous plasticizer (1) is controlled so that the resin composition in the molten state is 50 to 300 ° C., preferably 80 to 280 ° C. and above the plasticizing temperature of the molten resin composition. Cool and adjust to a viscosity suitable for subsequent injection and foaming.
[0062]
An injection apparatus (7) having an injection plunger (6) connected via an on-off valve (5) in a metering injection process is a molten resin composition whose temperature is controlled so as to have a viscosity suitable for injection and foaming. Sent to. When the on-off valve (5) is open, it is metered by retraction of the injection plunger (6) with the flow of molten resin composition into the injection device (7). In a normal injection molding apparatus, the back pressure is stopped immediately after completion of the measurement. In the present invention, however, back pressure is applied until the end of injection so that the molten resin composition does not foam in the injection apparatus (7). It is necessary to continue to control the internal pressure. The back pressure at this time needs to be higher than the critical pressure of carbon dioxide and / or nitrogen. Until the series of steps of gas dissolution process, cooling process and metering injection process is completed, the pressure above the critical pressure of the blowing agent is always maintained, so that the molten resin composition does not separate into resin and gas. It is necessary to. Once the resin and gas are separated, even if the system pressure is increased again, the resin and gas are not in a compatible state, so that the cells cannot be miniaturized.
[0063]
After completion of the measurement, the opening / closing valve (5) is switched to the closed state, and the compatible mixture of resin and gas is injected into the mold (8) by the injection plunger (6). A method of inducing the generation of cell nuclei by slightly reducing the pressure in the injection device (7) by sucking back the injection plunger (6) before performing post-metering injection is also suitably used.
[0064]
While the on-off valve (5) is switched to the closed state, the continuous plasticizer (1) is injected while the compatible mixture of resin and gas is injected into the mold (8) by the injection plunger (6). Since the resin composition is melted and carbon dioxide and / or nitrogen is supplied and kneaded independently of the process, quantitative mixing and dissolution of the thermoplastic resin and carbon dioxide and / or nitrogen can be continued. In the continuous plasticizer (1), the inside of the continuous plasticizer (1) can always be maintained at a pressure higher than the critical pressure of the foaming agent. The cooled molten resin composition is sent to the injection device (7), and the metering process is started.
[0065]
In order to produce a foam having cells having a fine average cell diameter and a uniform average cell density, carbon dioxide and / or nitrogen is in a supercritical state at least in the gas dissolving step, the cooling step, and the metering injection step. There is a need.
[0066]
The mold (8) immediately before being injected is filled with a high pressure gas supplied from the gas cylinder (13) or the booster pump via the pressure control valve (14) at a predetermined pressure. For example, when nitrogen is used as the high-pressure gas, the pressure is preferably equal to or higher than the critical pressure of carbon dioxide and / or nitrogen used as the blowing agent.
[0067]
In the foam control step, a molten resin composition in which a thermoplastic resin composition and carbon dioxide and / or nitrogen are in a compatible state is injected into a mold (8) filled with the high-pressure gas. After injection, a rapid pressure drop is caused in the mold (8) by rapidly removing the high-pressure gas filled in the mold (8). By this step, the gas impregnated in the resin becomes supersaturated and a large number of cell nuclei are generated.
[0068]
  The cell diameter can be controlled by the mold (8) temperature, the pressure inside the mold (8), and the pressure reduction rate, and the average cell diameter is 0.01 to 50 μm, preferably 0.01 to 20 μm. More preferably, it is 0.1-20 micrometers, More preferably, it is 1-20 micrometers, The average cell density is 108-1016Pieces / cmThreePreferably 108-1014Pieces / cmThree, More preferably 108-1012Pieces / cmThreeThe surface layer has substantially no cell of 1 μm or more, and has a thickness of 10 to 1000 μm.Non-foamed partA thermoplastic resin foam injection-molded article having the following is obtained.
[0069]
Further, as a method of causing a rapid pressure drop in the mold (8), a molten resin composition in which a thermoplastic resin composition and carbon dioxide and / or nitrogen are compatible is injected into the mold (8). After that, a method in which a part or all of the core is retracted, the capacity in the mold (8) is rapidly increased, and a rapid pressure drop in the mold (8) is preferably used.
[0070]
Even if each of these methods for controlling foaming is used alone, a sufficient foaming control effect can be obtained, but there is no problem in using the two methods in combination.
[0071]
As shown in FIG. 2, injection is performed via an open / close valve (5) between a continuous plasticizer (1) having a line for supplying a foaming agent and an injection device (7) having an injection plunger (6). Providing an adapter (2) having a mixing section connected to the outflow passage of the continuous plasticizing device (1) connected to the device (7) is a mixing of molten thermoplastic resin with carbon dioxide and / or nitrogen To facilitate the formation of a compatible state of the thermoplastic resin and carbon dioxide and / or nitrogen, and the resin in the molten state by the temperature control of the adapter (2), the subsequent injection and foaming It is preferable because it can be easily cooled to a viscosity suitable for the gas, and the gas dissolving step and the cooling step can be easily performed. Although there is no restriction | limiting in particular about the adapter (2) which has this mixing part, Since the kneading | mixing and cooling of resin are performed, the adapter (2) which incorporates a static mixer is used suitably.
[0072]
Also, as shown in FIG. 3, a resin accumulator device having a plunger connected to the injection device (7) via an opening / closing valve (5) before the injection device (7) having an injection plunger (6). The provision of (4) means that after the metering is finished, the open / close valve (5) is switched to the closed state, and the injection plunger (6) performs the injection into the mold (8) while the plasticizer ( The molten resin sent from 1) is sent to the resin accumulator device (4) provided immediately before the opening / closing valve (5), and the plunger of the resin accumulator device (4) is introduced by the inflow of the molten resin. By controlling the resin accumulator device (4) to retreat, it becomes easy to maintain the inside of the device system at a predetermined pressure, so that it is easy to maintain a compatible state of the molten resin composition, and foam injection molding Since it is easy to the cell diameter of the body fine preferable.
[0073]
As shown in FIG. 4, it is also possible to provide an injection device (7) having another injection plunger (6) in place of the resin accumulator device (4) having a plunger so that the inside of the apparatus system is kept at a predetermined pressure. Since it becomes easy to maintain, it is preferable because it is easy to maintain a compatible state of the molten resin composition and it becomes easy to make the cell diameter of the foam injection molded article fine.
[0074]
In the method of the present invention, carbon dioxide and / or nitrogen, which is a foaming agent, is supplied to the molten resin in the continuous plasticizing apparatus (1), kneaded sufficiently, and then injected into the injection plunger (6 via the on-off valve (5). The injection valve (5) is measured and injection-molded, so that the on-off valve (5) is closed even during the injection, and the continuous plasticizer (1) melts the resin independently of the injection process. Since carbon dioxide and / or nitrogen can be supplied and kneaded, it is easy to adjust the pressure in the system. Therefore, it is easy to make the cell diameter of the foam injection-molded product fine, and continuously. It becomes possible to produce a thermoplastic resin foam injection molded article having a large number of bubbles uniformly in a short time.
[0075]
  According to the present invention, the surface appearance is good and integrated.Non-foamed partIt is possible to efficiently produce a thermoplastic resin foam injection molded article having a surface layer.
[0076]
  FIG. 7 shows an example of a cross section of the thermoplastic resin foam injection molded article of the present invention. The molded body was integrated with the foamed inner layer portion in the surface layer portion.Non-foamed partIt has a structure with a surface layerNon-foamed partThe thickness of is about 10 to about 1000 μm. thisNon-foamed partIs a product in which a molten resin composition is introduced into a mold by injection and cooled to come into contact with the mold. Moreover, the thickness of a foam is 0.5-50 mm, Preferably it is 1-40 mm, More preferably, it is 2-30 mm. In the present invention, it is possible to obtain a foam injection molded article having an arbitrary thickness by adjusting the thickness of the mold cavity for injection molding of the molten resin composition in advance. A foam of 10 mm or more, and further 15 mm or more can be easily produced.
[0077]
Hereinafter, the present invention will be described with reference to examples, but the content of the present invention is not limited thereto.
[0078]
FIG. 1 is an example of a sectional view of a continuous plasticizing apparatus, an injection apparatus, and a mold showing Examples 1 and 4. FIG. 2 is an example of a sectional view of a continuous plasticizing device, an adapter, an injection device, and a mold showing Example 2. FIG. 3 is an example of a sectional view of a continuous plasticizing device, an adapter, a resin accumulator device, an injection device, and a mold showing Example 3. FIG. 4 is an example showing a method for producing a thermoplastic resin foam injection molded article of the present invention. FIG. 5 is an example showing a method for producing the thermoplastic resin foam of Comparative Example 3. FIG. 6 is an example showing a method for producing the thermoplastic resin foams of Comparative Examples 4-6. FIG. 7 is an example of a cross section of the thermoplastic resin foam injection molded article of the present invention. FIG. 8 is an example of a cross section of a thermoplastic resin foam produced by foam extrusion.
[0079]
【Example】
In addition, the physical property evaluation described in the Example and the comparative example was implemented in accordance with the following method.
[0080]
  1) Surface appearance
  The mold (8) cooling time at the time of injection molding was set to 60 seconds, and the surface of the molded foam was uniform and uniform by visual observation, and was integrated with the surface layer portion by cross-sectional observation of the foamNon-foamed partThe case where there is a circle is marked with ◯, and the case where there is a blister like blister is marked as x.
[0081]
2) Average cell diameter
A photograph taken with a scanning electron microscope was subjected to image processing, and the obtained circle-equivalent diameter was taken as the average cell diameter.
[0082]
3) Average cell density
A thermoplastic resin foam injection molded article was continuously molded, and three samples were obtained for every 10 molded articles. Photographs of three samples were taken with a scanning electron microscope, and the photographs were processed to 1 cm from the number of cells in a 500 μm square.2The number of cells per cell was calculated, and the value obtained by dividing the number of cells to the third power was taken as the cell density, and the average of the three points was taken as the average cell density.
[0083]
4) Cell uniformity
When the maximum cell diameter in a 500 μm square photograph taken with a scanning electron microscope is not more than 1.5 times the average cell diameter, the measured cell density at 3 points is 2/3 to 1 of the average cell density. .Circleincircle. In the case of less than 5 times, ◯ in the case of less than twice the average cell diameter and the measured cell density at three points within 1/2 to 2 times the average cell density, and x in the other cases. did.
[0084]
  5) Surface thickness
  From a cross-sectional photograph of the foam taken with a scanning electron microscope,Non-foamingThe thickness of the surface layer portion of was measured.
[0085]
  6) Izod impact strength
  The dumbbell pieces molded in Examples and Comparative Examples were cut, and a No. 2 A notched Izod impact test piece having a width of 2 mm and a thickness of 4 mm was prepared in accordance with JIS K7110, and an Izod impact test was performed.Non-foamed specimenThe intensity ratio to was measured. The strength contrast of polystyreneNon-foamed specimenThe Izod impact strength of Topolex 555-57 (Mitsui Toatsu Chemical Co., Ltd.) is 1.76 kg-cm / cm2Topolex 525-51 (manufactured by Mitsui Toatsu Chemicals) 1.54 kg-cm / cm2, Topolex 575-57 (Mitsui Toatsu Chemical Co., Ltd.) 1.83kg-cm / cm2Met.
[0086]
Example 1
100 parts by weight of pellets of polystyrene resin (Topolex 555-57, manufactured by Mitsui Toatsu Chemical Co., Ltd.) having a melt flow index of 2.6 g / 10 min at 200 ° C. and 5 kg are 30 mm in diameter from the hopper (9). / D = 30 fed into a continuous plasticizer (1) having a screw (12), melted by heating at 230 ° C., and 180 kg / cm by a booster pump (11)2Then, 15 parts by weight of carbon dioxide brought to a supercritical state by increasing the pressure was fed to the place where the resin was completely melted. Carbon dioxide and molten resin are kneaded and dissolved in the continuous plasticizer (1), the resin temperature of the molten resin composition is gradually cooled to 150 ° C., and weighed to an injection device (7) set at 150 ° C. It injected into the metal mold | die (8) set to ° C. At this time, nitrogen gas is introduced into the mold (8) immediately before being injected at 80 kg / cm 2.2It was made to fill under the pressure of. After the injection is completed, the nitrogen gas filled in the mold (8) is drawn out in 1 second, and the core of the mold (8) is moved backward by 2 mm, so that the dumbbell piece for tensile test (test) A piece thickness of 4 mm) was obtained.
[0087]
  Table 1 shows the results of the foam evaluation. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0088]
Example 2
In Example 1, an adapter (2) incorporating a static mixer is connected to the outflow passage of the continuous plasticizer (1), and the temperature of the adapter (2) is 200 ° C, 160 ° C, 120 ° C in order from the flow direction. A tensile test dumbbell piece, which is a polystyrene resin foam molded article, was obtained in accordance with Example 1 except that the resin temperature of the molten resin composition was set to 120 ° C.
[0089]
  Table 1 shows the results of the foam evaluation. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0090]
Example 3
In Example 2, a tensile test dumbbell piece, which is a polystyrene resin foam molded article, was obtained in accordance with Example 2 except that the resin accumulator device (4) was connected to the outflow passage of the adapter (2).
[0091]
  Table 1 shows the results of the foam evaluation. Izod impact strength is improved, surface appearance is good, the foam layer has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0092]
Example 4
In Example 1, as a method of rapidly changing the pressure in the mold (8), nitrogen gas was introduced into the mold (8) immediately before being injected at 80 kg / cm.2The tensile test dumbbell piece, which is a polystyrene resin foam molded article according to Example 1, except that the core in the mold (8) is rapidly retracted and decompressed after completion of injection instead of the method of filling under pressure of Got.
[0093]
  Table 1 shows the results of the foam evaluation. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0094]
Example 5
In Example 1, a dumbbell for tensile test, which is a polystyrene resin foam molded article, was obtained in accordance with Example 1 except that the temperature of the mold (8) was 20 ° C.
[0095]
  Table 1 shows the results of the foam evaluation. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0096]
Example 6
In Example 1, a tensile test dumbbell piece, which is a polystyrene resin foam molded article, was obtained in accordance with Example 1 except that the temperature of the mold (8) was set to 80 ° C.
[0097]
  Table 1 shows the results of the foam evaluation. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0098]
Example 7
In Example 1, a tensile test dumbbell piece, which is a polystyrene resin foam molded article, was obtained in accordance with Example 1 except that the amount of carbon dioxide was 5 parts by weight.
[0099]
  Table 1 shows the results of the foam evaluation. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0100]
Comparative Example 1
In Example 1, the mold (8) immediately before being injected was not filled with high-pressure nitrogen gas, but was kept at normal pressure air, and the mold core was retreated in advance to a thickness of 4 mm. Except for the above, a dumbbell piece for tensile test which is a polystyrene resin foam molded article was obtained in accordance with Example 1.
[0101]
Table 1 shows the results of the foam evaluation. The foam intended by the present invention could not be produced because the Izod impact strength was low, the surface appearance was poor, the cell was not a fine average cell diameter, and the number of cells was small.
[0102]
Comparative Example 2
In Example 1, according to the method of Example 1, except that the continuous plasticizing apparatus (1) during the injection process does not knead and dissolve carbon dioxide and the molten resin, and restarts the kneading and dissolution after the injection process. A tensile test dumbbell piece, which is a polystyrene resin foam molded article, was obtained.
[0103]
Table 1 shows the results of the foam evaluation. The foam intended by the present invention could not be produced because the Izod impact strength was low, the surface appearance was poor, the cell was not a fine average cell diameter, and the number of cells was small.
[0104]
Further, when the cross section of the foam was observed with a scanning electron microscope, non-uniform bubbles having a diameter of 50 to 100 μm were dispersed.
[0105]
Comparative Example 3
100 parts by weight of pellets of polystyrene resin (made by Mitsui Toatsu Chemical Co., Ltd., Topolex 555-57) having a melt flow index of 2.6 g / 10 min at 200 ° C. and 5 kg, a caliber of 30 mm, L / D = 30 In-line injection molding machine with a screw of 30 (cylinder temperature 230-150 ° C.), heated and melted at 230 ° C., 180 kg / cm by pressure pump (11)2Then, 15 parts by weight of carbon dioxide brought to a supercritical state by increasing the pressure was fed to the place where the resin was completely melted. After the measurement, the screw rotation was stopped, and the gas melting process and the cooling process were interrupted. Also, the screw back pressure was released as the screw stopped. After weighing, the molten resin was injected into a mold (8) set at 50 ° C. At this time, nitrogen gas is introduced into the mold (8) immediately before being injected at 80 kg / cm 2.2It was made to fill under the pressure of. After the injection is completed, the nitrogen gas filled in the mold (8) is drawn out in 1 second, and the core of the mold (8) is moved backward by 2 mm, so that the dumbbell piece for tensile test (test) A piece thickness of 4 mm) was obtained.
[0106]
Table 1 shows the results of the foam evaluation. The Izod impact strength was lowered, the surface appearance was poor, the cell was not a fine average cell diameter, and the number of cells was not preferable, and the foam intended in the present invention could not be produced.
[0107]
Examples 8-10
A mold (8) capable of forming a sheet having a size of 80 × 80 × 6 (thickness) mm was attached to the same injection molding machine as in Example 3. The thickness was adjusted to 6 mm to 15 mm depending on the core back amount. The same polystyrene as in Example 3 was used as the molding material, and the same as in Example 3 except that the amount of carbon dioxide injected was 8 parts by weight. The specific gravity of the obtained sheet, the thickness of the non-foamed skin layer, the average cell diameter of the foamed layer, and the cell density were measured by SEM photograph observation, and the surface impact strength (fracture energy) was measured using a high-speed impact tester (RIT8000 manufactured by Rheometrics) Was measured at 0 ° C., hitting diameter 1/2 inch, cradle diameter 2 inch, hitting speed 10 m / sec. The results are shown in Table 2. The average cell diameter was small even when the thickness was thick.
[0108]
Examples 11-12
In Examples 8 to 10, this was carried out except that a mold (8) capable of forming a sheet having a size of 80 × 80 × 15 (thickness) mm was attached and the thickness could be adjusted to 20 mm to 50 mm depending on the amount of core back. A foam sheet was obtained according to Examples 8-10. The results are shown in Table 2. The average cell diameter was small even when the thickness was thick.
[0109]
  Comparative Examples 4-8
Tandem type consisting of a first extruder (screw diameter 50 mm, L / D 25 cylinder temperature 180-220 ° C.) (17) and a second extruder (screw diameter 65 mm, L / D = 38 cylinder temperature 150 ° C.) (18) The extrusion die and the cooling device (19) shown in FIG. 6 are attached to the extruder, the die temperature is set to 140, and 8 parts by weight of carbon dioxide is injected from 400 mm from the screw tip of the first extruder to obtain a foam sheet (20). . The lip opening, extrusion amount, and die internal pressure were adjusted to obtain a sheet having a thickness of 6 to 15 mm. The specific gravity, average cell diameter, cell density, and surface impact strength were measured in the same manner as in Example 8. The results are shown in Table 2. The average cell diameter was larger as the thickness was thicker than in Examples 8 to 12 by the injection molding method. Moreover, the surface impact strength was also low compared with Examples 8-12. Further, as shown in FIG. 8, the surface layer of the foam sheet obtained by foam extrusion molding is foamed in the same manner as the inner layer portion and is dense.Non-foamed layerDid not exist.
[0110]
Example 13
Dry 1 part by weight of polydimethylsiloxane on 100 parts by weight of pellets of polystyrene resin (Topolex 555-57 manufactured by Mitsui Toatsu Chemical Co., Ltd.) having a melt flow index of 2.6 g / 10 min at 200 ° C. and 5 kg. After blending, the mixture is fed from a hopper (9) into a continuous plasticizer (1) having a screw (12) of 30 mm in diameter and L / D = 30, heated and melted at 230 ° C., and a pressure pump (11 ) 180kg / cm2Then, 15 parts by weight of carbon dioxide brought to a supercritical state by increasing the pressure was fed to the place where the resin was completely melted. Carbon dioxide and molten resin are kneaded and dissolved in the continuous plasticizer (1), the resin temperature of the molten resin composition is gradually cooled to 150 ° C., and weighed to an injection device (7) set at 150 ° C. It injected into the metal mold | die (8) set to ° C. At this time, nitrogen gas is introduced into the mold (8) immediately before being injected at 80 kg / cm 2.2It was made to fill under the pressure of. After the injection is completed, the nitrogen gas filled in the mold (8) is drawn out in 1 second, and the core of the mold (8) is moved backward by 2 mm, so that the dumbbell piece for tensile test (test) A piece thickness of 4 mm) was obtained. During this time, the mold was continuously molded with a cooling time of 30 seconds in the mold (8). However, the surface of the foam was not defective due to secondary foaming after release.
[0111]
  Table 3 shows the results of the foam evaluation. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0112]
Example 14
In Example 13, a foam was obtained according to Example 13 except that 2 parts by weight of talc having an average particle diameter of 2 μm was added in addition to polystyrene resin and polydimethylsiloxane.
[0113]
Table 3 shows the results of the foam evaluation. The foam had improved Izod impact strength, good surface appearance, fine average cell diameter, and uniform average cell density.
[0114]
  Examples 15-18
In Example 13, a foam was obtained in accordance with Example 13 except that the ratio of polystyrene resin, polydimethylsiloxane and carbon dioxide was changed to the ratio shown in Table 3. Table 3 shows the results of the foam evaluation. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0115]
  Example 19
In Example 13, except that the polystyrene resin was a polystyrene resin (Mitsui Toatsu Chemical Co., Ltd., Topolex 525-51) having a melt flow index of 10 g / 10 min at 200 ° C. and 5 kg, according to Example 13. A foam was obtained. Table 3 shows the results of the foam evaluation. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0116]
  Example 20
Example 13 is the same as Example 13 except that the polystyrene resin is a polystyrene resin having a melt flow index of 1.8 g / 10 min at 200 ° C. and 5 kg (Mitsui Toatsu Chemical Co., Ltd., Topolex 575-57). According to 13, a foam was obtained. Table 3 shows the results of the foam evaluation. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0117]
Comparative Examples 9-11
In Example 13, a foam was obtained according to Example 13 except that the ratios of polystyrene resin, polydimethylsiloxane and carbon dioxide were changed to the ratios shown in Table 3.
Table 3 shows the results of the foam evaluation. It was not preferable from the viewpoints of poor surface appearance, fine average cell diameter, small number of cells, etc., and the foam intended in the present invention could not be produced.
[0118]
Example 21
1 part by weight of montanic acid perfluoropropyl ester per 100 parts by weight of pellets of polystyrene resin (Topolex 555-57 manufactured by Mitsui Toatsu Chemical Co., Ltd.) having a melt flow index of 2.6 g / 10 min at 200 ° C. and 5 kg After dry blending the parts, the mixture is fed from a hopper (9) into a continuous plasticizer (1) having a screw (12) of 30 mm in diameter and L / D = 30, heated and melted at 230 ° C., and pressurized. 180kg / cm by pump (11)2Then, 15 parts by weight of carbon dioxide brought to a supercritical state by increasing the pressure was fed to the place where the resin was completely melted. Carbon dioxide and molten resin are kneaded and dissolved in the continuous plasticizer (1), the resin temperature of the molten resin composition is gradually cooled to 150 ° C., and weighed to an injection device (7) set at 150 ° C. It injected into the metal mold | die (8) set to ° C. At this time, nitrogen gas is introduced into the mold (8) immediately before being injected at 80 kg / cm 2.2It was made to fill under the pressure of. After the injection is completed, the nitrogen gas filled in the mold (8) is drawn out in 1 second, and the core of the mold (8) is moved backward by 2 mm, so that the dumbbell piece for tensile test (test) A piece thickness of 4 mm) was obtained. During this time, the mold was continuously molded with a cooling time of 30 seconds in the mold (8). However, the surface of the foam was not defective due to secondary foaming after release.
[0119]
  The results of the foam evaluation are shown in Table 4. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0120]
Example 22
In Example 21, a foam was obtained according to Example 21 except that 2 parts by weight of talc having an average particle diameter of 2 μm was added in addition to polystyrene resin and montanic acid perfluoropropyl ester.
[0121]
  The results of the foam evaluation are shown in Table 4. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0122]
  Examples 23-26
In Example 21, a foam was obtained according to Example 21, except that the ratio of polystyrene resin, montanic acid perfluoropropyl ester and carbon dioxide was changed to the ratio shown in Table 4. The results of the foam evaluation are shown in Table 4. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0123]
  Example 27
In Example 21, except that the polystyrene resin was a polystyrene resin (Topolex 525-51, manufactured by Mitsui Toatsu Chemical Co., Ltd.) having a melt flow index of 10 g / 10 min at 200 ° C. and 5 kg, in accordance with Example 21 A foam was obtained. The results of the foam evaluation are shown in Table 4. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0124]
  Example 28
Example 21 is the same as Example 21, except that the polystyrene resin is a polystyrene resin (Mitsui Toatsu Chemical Co., Ltd., Topolex 575-57) having a melt flow index of 1.8 g / 10 min at 200 ° C. and 5 kg. A foam was obtained according to 21. The results of the foam evaluation are shown in Table 4. Izod impact strength is improved, surface appearance is good, the foam part has cells with a uniform average cell density with a fine average cell diameter in the intermediate layer, and the foam part is integrated in the surface layerNon-foamed partIt was a foam having.
[0125]
Comparative Examples 12-14
In Example 21, a foam was obtained in accordance with Example 21 except that the ratio of polystyrene resin, montanic acid perfluoropropyl ester and carbon dioxide was changed to the ratio shown in Table 4.
[0126]
The results of the foam evaluation are shown in Table 4. The Izod impact strength was lowered, the surface appearance was poor, the cell was not a fine average cell diameter, and the number of cells was not preferable, and the foam intended in the present invention could not be produced.
[0127]
[Table 1]
Figure 0004144916
[0128]
[Table 2]
Figure 0004144916
[0129]
[Table 3]
Figure 0004144916
[0130]
[Table 4]
Figure 0004144916
[0131]
【The invention's effect】
  Of the present inventionMolded body produced by a method for producing a thermoplastic resin foam injection molded articleHas a good surface appearance and integratedNon-foamed partIn the surface layer, and has a cell with a fine average cell diameter and a uniform average cell density.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an example of a method for producing a thermoplastic resin foam injection molded article of the present invention.
FIG. 2 is a schematic configuration diagram showing an example of a method for producing a thermoplastic resin foam injection molded article of the present invention.
FIG. 3 is a schematic configuration diagram showing an example of a method for producing a thermoplastic resin foam injection molded article of the present invention.
FIG. 4 is a schematic configuration diagram showing an example of a method for producing a thermoplastic resin foam injection molded article of the present invention.
FIG. 5 is a schematic configuration diagram showing a thermoplastic resin foam production method (Comparative Example 3) using a normal extruder.
FIG. 6 is a schematic configuration diagram showing a method for producing a thermoplastic resin foam by extrusion molding (Comparative Examples 4 to 6).
FIG. 7 shows an example of a cross section of the thermoplastic resin foam injection molded article of the present invention.
FIG. 8 is an example of a cross section of a thermoplastic resin foam produced by foam extrusion.
[Explanation of symbols]
(1) Continuous plasticizer
(2) Adapter
(3) Resin accumulator plunger
(4) Resin accumulator device
(5) Open / close valve
(6) Injection plunger
(7) Injection device
(8) Mold
(9) Hopper
(10) Gas cylinder
(11) Booster pump
(12) Screw
(13) Gas cylinder
(14) Pressure control valve
(15) Open / close valve
(16) In-line injection molding machine
(17) First extruder
(18) Second extruder
(19) Cooling device
(20) Thermoplastic resin foam

Claims (8)

内層に平均セル径が０．０１〜５０μｍ、平均セル密度が１０ 8 〜１０ 16 個／ｃｍ 3 である発泡部分と、表層に前記発泡部分と一体化した厚さ１０〜１０００μｍの非発泡部分とを有する熱可塑性樹脂発泡射出成形体を製造する方法であって、
（I）発泡剤を供給するラインを有する連続可塑化装置（１）内で、１００〜４５０℃で熱可塑性樹脂１００重量部を溶融し、超臨界状態の二酸化炭素および／または窒素を、熱可塑性樹脂１００重量部当たり０．１〜３０重量部添加し、熱可塑性樹脂と超臨界状態の二酸化炭素および／または窒素の定量的混合溶解を継続し、相溶状態の溶融樹脂組成物を形成するガス溶解工程、
（II）連続可塑化装置（１）内で、前記二酸化炭素および／または窒素の臨界圧力以上の圧力を維持したまま該溶融樹脂組成物を５０〜３００℃の温度に下げる冷却工程、
（III）連続可塑化装置（１）に接続した射出プランジャー（６）を有する射出装置（７）により、前記二酸化炭素および／または窒素の臨界圧力以上の圧力を維持したまま冷却した該溶融樹脂組成物を計量し、金型（８）内に充填する計量射出工程、及び、
（IV）金型（８）内の圧力を前記二酸化炭素および／または窒素の前記臨界圧力以下の圧力に低下することによりセル核を発生させ、該セル径を制御する発泡制御工程からなり、計量射出工程までは、二酸化炭素および／または窒素の超臨界状態を維持し、かつ連続可塑化装置（１）によるガス溶解工程および冷却工程と射出装置（７）による計量射出工程を独立に行うことを特徴とする熱可塑性樹脂発泡射出成形体を製造する方法。 A foamed portion having an average cell diameter of 0.01 to 50 μm and an average cell density of 10 8 to 10 16 cells / cm 3 in the inner layer, and a non-foamed portion having a thickness of 10 to 1000 μm integrated with the foamed portion in the surface layer A method for producing a thermoplastic resin foam injection molded article having
(I) In a continuous plasticizer (1) having a line for supplying a foaming agent, 100 parts by weight of a thermoplastic resin is melted at 100 to 450 ° C., and carbon dioxide and / or nitrogen in a supercritical state is thermoplasticized. 0.1 to 30 parts by weight per 100 parts by weight of resin, a gas that continues quantitative mixing and dissolution of the thermoplastic resin and carbon dioxide and / or nitrogen in a supercritical state to form a molten resin composition in a compatible state Dissolution process,
(II) a cooling step of lowering the molten resin composition to a temperature of 50 to 300 ° C. while maintaining a pressure equal to or higher than the critical pressure of carbon dioxide and / or nitrogen in the continuous plasticizer (1);
(III) The molten resin cooled by an injection device (7) having an injection plunger (6) connected to the continuous plasticizer (1) while maintaining a pressure higher than the critical pressure of carbon dioxide and / or nitrogen. A metering injection step of metering the composition and filling the mold (8); and
(IV) comprising a foam control step of generating cell nuclei by controlling the pressure in the mold (8) to a pressure lower than the critical pressure of the carbon dioxide and / or nitrogen, and controlling the cell diameter; Until the injection process, the supercritical state of carbon dioxide and / or nitrogen is maintained, and the gas dissolution process by the continuous plasticizer (1) and the cooling process and the metering injection process by the injection apparatus (7) are performed independently. method for producing a thermoplastic resin foam injection molded characterized. 発泡剤を供給するラインを有する連続可塑化装置（１）と、射出プランジャー（６）を有する射出装置（７）の間に、開閉バルブ（５）を介して射出装置（７）に接続される該連続可塑化装置（１）の流出路に接続された、混合部を有するアダプター（２）を設けることを特徴とする請求項１記載の熱可塑性樹脂発泡射出成形体の製造方法。Between a continuous plasticizer (1) having a line for supplying a blowing agent and an injection device (7) having an injection plunger (6), it is connected to the injection device (7) via an open / close valve (5). the continuous connected to the outflow path of the plasticizing device (1), method for producing a thermoplastic resin foam injection molded body according to claim 1, wherein the provision of the adapter (2) having a mixing section that. 厚さが０．５〜５０ｍｍの発泡体が製造可能な請求項１記載の熱可塑性樹脂発泡射出成形体の製造方法。  The method for producing a thermoplastic resin foam injection-molded article according to claim 1, wherein a foam having a thickness of 0.5 to 50 mm can be produced. 厚さが１０〜５０ｍｍの発泡体が製造可能な請求項１記載の熱可塑性樹脂発泡射出成形体の製造方法。  The method for producing a thermoplastic resin foam injection molded article according to claim 1, wherein a foam having a thickness of 10 to 50 mm can be produced. 発泡制御工程を、溶融樹脂組成物を射出したのちに金型（８）内に充填した高圧ガスの脱ガスおよび／または金型（８）のコアの少なくとも一部の後退で行う請求項１記載の熱可塑性樹脂発泡射出成形体の製造方法。  The foam control step is performed by degassing the high-pressure gas filled in the mold (8) and / or retreating at least a part of the core of the mold (8) after injecting the molten resin composition. Process for producing a thermoplastic resin foam injection molded article. 熱可塑性樹脂にさらに整泡剤を０．１〜１０重量部添加することを特徴とする請求項１記載の熱可塑性樹脂発泡射出成形体の製造方法。  The method for producing a thermoplastic resin foam injection molded article according to claim 1, wherein 0.1 to 10 parts by weight of a foam stabilizer is further added to the thermoplastic resin. 発泡剤を供給するラインを有する連続可塑化装置（１）と、射出プランジャー（６）を有する射出装置（７）の間に、開閉バルブ（５）を介して射出装置（７）に接続される、プランジャーを有する樹脂アキュームレータ装置（４）を設けることを特徴とする請求項１記載の熱可塑性樹脂発泡射出成形体の製造方法。Between a continuous plasticizer (1) having a line for supplying a blowing agent and an injection device (7) having an injection plunger (6), it is connected to the injection device (7) via an open / close valve (5). A method for producing a thermoplastic resin foam injection-molded article according to claim 1, wherein a resin accumulator device (4) having a plunger is provided. 混合部を有するアダプター（２）と、射出プランジャー（６）を有する射出装置（７）の間に、開閉バルブ（５）を介して射出装置（７）に接続される、プランジャーを有する樹脂アキュームレータ装置（４）を設けることを特徴とする請求項７記載の熱可塑性樹脂発泡射出成形体の製造方法。A resin having a plunger, which is connected to the injection device (7) via an open / close valve (5) between an adapter (2) having a mixing portion and an injection device (7) having an injection plunger (6). An accumulator device (4) is provided, The manufacturing method of the thermoplastic resin foam injection-molding object according to claim 7 characterized by things.
JP07164497A 1996-04-04 1997-03-25 Thermoplastic resin foam injection molded body and method for producing the same Expired - Fee Related JP4144916B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP07164497A JP4144916B2 (en) 1996-04-04 1997-03-25 Thermoplastic resin foam injection molded body and method for producing the same

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
JP8249396 1996-04-04
JP8-82493 1996-12-19
JP8-339702 1996-12-19
JP33970296 1996-12-19
JP07164497A JP4144916B2 (en) 1996-04-04 1997-03-25 Thermoplastic resin foam injection molded body and method for producing the same

Related Child Applications (1)

Application Number Title Priority Date Filing Date
JP2005294942A Division JP4339296B2 (en) 1996-04-04 2005-10-07 Method for producing thermoplastic resin foam injection molded article

Publications (2)

Publication Number Publication Date
JPH10230528A JPH10230528A (en) 1998-09-02
JP4144916B2 true JP4144916B2 (en) 2008-09-03

Family

ID=27300711

Family Applications (1)

Application Number Title Priority Date Filing Date
JP07164497A Expired - Fee Related JP4144916B2 (en) 1996-04-04 1997-03-25 Thermoplastic resin foam injection molded body and method for producing the same

Country Status (1)

Country Link
JP (1) JP4144916B2 (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013027615A1 (en) 2011-08-19 2013-02-28 日立マクセル株式会社 Kneading device, method for producing thermoplastic resin molded body, and foam injection molding method
WO2014126082A1 (en) 2013-02-18 2014-08-21 日立マクセル株式会社 Method for producing molded foam body
WO2018131372A1 (en) 2017-01-11 2018-07-19 マクセル株式会社 Method and apparatus for manufacturing foamed product
WO2019003748A1 (en) 2017-06-26 2019-01-03 マクセル株式会社 Method for manufacturing foam molded body and foam molded body
KR20190112808A (en) 2017-03-10 2019-10-07 마쿠세루 가부시키가이샤 Manufacturing method and apparatus for foam molding
KR20190142427A (en) 2016-03-15 2019-12-26 마쿠세루 가부시키가이샤 Method and apparatus for manufacturing foam molded body
KR20200021939A (en) 2017-06-26 2020-03-02 맥셀 홀딩스 가부시키가이샤 Method of manufacturing circuit components and circuit components
US10632663B2 (en) 2015-07-08 2020-04-28 Maxell, Ltd. Process and device for producing molded foam
US10703029B2 (en) 2014-10-31 2020-07-07 Maxell, Ltd. Process and device for producing foamed molded object
DE112022001487T5 (en) 2021-03-16 2024-01-04 Shibaura Machine Co., Ltd. Foam casting process, control method for an injection molding machine for foam casting, and injection molding machine for foam casting

Families Citing this family (61)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6884823B1 (en) 1997-01-16 2005-04-26 Trexel, Inc. Injection molding of polymeric material
JP3218397B2 (en) * 1997-05-21 2001-10-15 旭化成株式会社 Injection molding of thermoplastic resin
JP3998374B2 (en) * 1998-07-16 2007-10-24 三井化学株式会社 Method for adding supercritical carbon dioxide and method for producing thermoplastic resin foam using the addition method
KR100572943B1 (en) * 1998-11-04 2006-04-24 트레셀 인코포레이티드 Molded Polymeric Material Including Microcellular, Injection-Molded, and low-Density Polymeric Material
JP3904129B2 (en) * 1998-12-08 2007-04-11 日東電工株式会社 Method and apparatus for producing foamed adhesive tape or sheet
WO2001015882A1 (en) 1999-08-30 2001-03-08 Sekisui Chemical Co., Ltd. Production method for thermoplastic resin foam, molding mold therefor and thermoplastic resin foam
JP3320690B2 (en) * 1999-09-20 2002-09-03 積水化学工業株式会社 Thermoplastic porous body
JP3544899B2 (en) * 1999-09-02 2004-07-21 住友軽金属工業株式会社 Method of suppressing or avoiding corrosion and discoloration in foamed copper tube
JP4276754B2 (en) 1999-11-11 2009-06-10 株式会社日本製鋼所 Thermoplastic resin foam molding method
JP3716904B2 (en) * 1999-12-01 2005-11-16 株式会社日本製鋼所 Foam molding method and molding apparatus
JP3517622B2 (en) * 1999-12-08 2004-04-12 株式会社日本製鋼所 Method and apparatus for producing foam
JP3521306B2 (en) * 1999-12-08 2004-04-19 株式会社日本製鋼所 Method and apparatus for producing sandwich foam
JP2001198942A (en) * 2000-01-24 2001-07-24 Sumitomo Heavy Ind Ltd Method for molding foamed molded article and injection molding machine
JP4689789B2 (en) * 2000-03-31 2011-05-25 株式会社日本製鋼所 Molded resin magnet molding method
JP2001277278A (en) * 2000-03-31 2001-10-09 Japan Steel Works Ltd:The Method for molding glass fiber reinforced thermoplastic resin molded article and glass fiber reinforced thermoplastic resin molded article
US7107601B2 (en) 2000-06-14 2006-09-12 Canon Kabushiki Kaisha Foam molding method and apparatus
JP2001353743A (en) * 2000-06-14 2001-12-25 Canon Inc Molded object, placing object, and method and apparatus for manufacturing resin molded article
JP2001353744A (en) * 2000-06-14 2001-12-25 Canon Inc Resin molded article for acoustic instrument of imaging instrument, housing structure of acoustic instrument or imaging instrument, resin molded article molded from resin material, damping member, damping mechanism, and fastening member
JP4640814B2 (en) * 2000-06-22 2011-03-02 三井化学株式会社 Thermoplastic resin foam
JP3425559B2 (en) * 2001-01-11 2003-07-14 積水化学工業株式会社 Injection molding equipment for thermoplastic resin molded products
JP4618910B2 (en) * 2001-03-08 2011-01-26 株式会社プライムポリマー Injection foaming resin composition
US7008202B2 (en) 2001-03-08 2006-03-07 The Japan Steel Works, Ltd. Method and apparatus for forming thermoplastic resin foam
JP2002307473A (en) * 2001-04-09 2002-10-23 Grand Polymer Co Ltd Method for producing foamed molding
JP4610782B2 (en) * 2001-05-01 2011-01-12 日本ポリウレタン工業株式会社 Construction method of embankment and manufacturing method of polyurethane foam for civil engineering
JP3609038B2 (en) * 2001-05-21 2005-01-12 株式会社日本製鋼所 Three-layer laminate molding method and molding die
JP2002355824A (en) * 2001-05-31 2002-12-10 Japan Polychem Corp Method for manufacturing thermoplastic resin molded object improved in heat-resistant rigidity, and molded object
JP2003001666A (en) * 2001-06-20 2003-01-08 Teijin Meton Kk Large-sized septic tank
CN1604935A (en) * 2001-06-22 2005-04-06 出光兴产株式会社 Composite resin composition, resin foam, and method for producing same
JP2003039512A (en) * 2001-08-01 2003-02-13 Sumitomo Chem Co Ltd Thermoplastic resin foamed molded object
JP2003127639A (en) * 2001-10-19 2003-05-08 Inoac Corp Air conditioner dumper
JP2003211481A (en) * 2002-01-25 2003-07-29 Chisso Corp Method for molding using thermoplastic resin and foaming agent and molded product obtained by the same
US7704423B2 (en) 2002-02-28 2010-04-27 Ube Machinery Corporation, Ltd. Method for expansion injection molding
JP2003266500A (en) * 2002-03-13 2003-09-24 Sanyo Electric Co Ltd Molding apparatus for optical disk and molding method using the same
JP2003313346A (en) * 2002-04-19 2003-11-06 Fujitsu Ltd Flame-retardant resin molding for portable device casing
JP2003337588A (en) * 2002-05-21 2003-11-28 Idemitsu Petrochem Co Ltd Sound absorbing body and sound absorbing structure
JP4223236B2 (en) * 2002-06-21 2009-02-12 株式会社名機製作所 Gas impregnated resin injection apparatus and injection molding method
JP4136904B2 (en) * 2003-11-12 2008-08-20 三菱エンジニアリングプラスチックス株式会社 Injection foam molding method
JP4330485B2 (en) * 2004-04-20 2009-09-16 三菱エンジニアリングプラスチックス株式会社 Injection foam molding method
JP2005328297A (en) * 2004-05-13 2005-11-24 Sony Corp Diaphragm of speaker and method for manufacturing diaphragm of speaker
JP4536446B2 (en) * 2004-07-28 2010-09-01 株式会社カネカ Method for producing thermoplastic resin foam molded body and molded body
JP5168832B2 (en) * 2005-07-19 2013-03-27 東レ株式会社 Polylactic acid resin composition and method for producing the same
JP4839728B2 (en) * 2005-08-25 2011-12-21 宇部興産機械株式会社 Thermoplastic resin multilayer molding method and multilayer molding apparatus
WO2008112815A2 (en) 2007-03-12 2008-09-18 University Of Washington Methods for altering the impact strength of noncellular thermoplastic materials
JP2009061592A (en) * 2007-09-04 2009-03-26 Mazda Motor Corp Method of molding foamed resin molded article and molding apparatus
JP2008044384A (en) * 2007-10-29 2008-02-28 Mitsui Chemicals Inc Manufacturing process of foam molding
JP5160336B2 (en) * 2008-08-07 2013-03-13 テクノポリマー株式会社 Resin foam molding and method for producing the same
WO2012103451A2 (en) * 2011-01-27 2012-08-02 New Balance Athletic Shoe, Inc. Injection molding systems and methods for forming materials used in footwear and materials manufactured by said systems and methods
JP5801072B2 (en) * 2011-03-16 2015-10-28 バンドー化学株式会社 Foam gear
JP5660943B2 (en) * 2011-03-16 2015-01-28 東洋ゴム工業株式会社 Mold equipment
JP6039384B2 (en) * 2012-11-27 2016-12-07 帝人株式会社 Thermoplastic resin composition for supercritical foam molding with excellent mold corrosiveness
JP6080611B2 (en) * 2013-02-26 2017-02-15 東洋製罐株式会社 Method for producing foamable injection-molded body and injection device therefor
CN105074324B (en) * 2013-02-26 2017-07-18 三菱化学株式会社 Thermoplastic resin formed body and its manufacture method, thermoplastic resin light guide, light supply apparatus and liquid crystal display device
JP5710813B1 (en) * 2014-03-05 2015-04-30 株式会社日本製鋼所 Injection molding machine screw and injection molding machine
KR20170015922A (en) * 2014-05-30 2017-02-10 세끼스이 테크노 세이께이 가부시끼가이샤 Foam-molded article and method for manufacturing same
JP6815748B2 (en) * 2016-05-11 2021-01-20 日東電工株式会社 Conductive resin composite manufacturing method and conductive resin composite
JP6831317B2 (en) * 2017-11-07 2021-02-17 株式会社神戸製鋼所 Mixer
CN115648529A (en) * 2018-09-21 2023-01-31 耐克创新有限合伙公司 Molding system and method
EP4026678A4 (en) * 2019-10-10 2022-10-19 Showa Denko Materials Co., Ltd. Foam-molded product, method of manufacturing foam-molded product, and method of suppressing poor appearance of foam-molded product
US11267175B2 (en) 2019-10-15 2022-03-08 King Steel Machinery Co., Ltd. Injection molding system
JP7352466B2 (en) 2019-12-27 2023-09-28 Ｅｎｅｏｓ株式会社 Composition for foam molding and foam molded product
US20220402445A1 (en) * 2020-02-10 2022-12-22 Showa Denko Materials Co., Ltd. Molded body, and method for producing molded body

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3062629B2 (en) * 1991-03-15 2000-07-12 東芝機械株式会社 Continuous plasticizing injection molding apparatus and injection molding method
US5158986A (en) * 1991-04-05 1992-10-27 Massachusetts Institute Of Technology Microcellular thermoplastic foamed with supercritical fluid
JP3303213B2 (en) * 1992-06-11 2002-07-15 東芝機械株式会社 Continuous plasticizing injection molding method and apparatus
JP3387549B2 (en) * 1993-04-02 2003-03-17 大成プラス株式会社 Foam injection molding method
JP3007920B2 (en) * 1993-10-19 2000-02-14 東芝機械株式会社 Continuous plasticization type injection molding equipment

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013027615A1 (en) 2011-08-19 2013-02-28 日立マクセル株式会社 Kneading device, method for producing thermoplastic resin molded body, and foam injection molding method
US8980147B2 (en) 2011-08-19 2015-03-17 Hitachi Maxell, Ltd. Kneading apparatus, method for producing thermoplastic resin molded product, and foam injection molding method
US9186634B2 (en) 2011-08-19 2015-11-17 Hitachi Maxell, Ltd. Kneading apparatus, method for producing thermoplastic resin molded product, and foam injection molding method
US9718217B2 (en) 2011-08-19 2017-08-01 Hitachi Maxell, Ltd. Kneading apparatus, method for producing thermoplastic resin molded product, and foam injection molding method
WO2014126082A1 (en) 2013-02-18 2014-08-21 日立マクセル株式会社 Method for producing molded foam body
US9884439B2 (en) 2013-02-18 2018-02-06 Hitachi Maxell, Ltd. Method for producing foamed molded product
US10703029B2 (en) 2014-10-31 2020-07-07 Maxell, Ltd. Process and device for producing foamed molded object
US10632663B2 (en) 2015-07-08 2020-04-28 Maxell, Ltd. Process and device for producing molded foam
EP4108406A1 (en) 2015-07-08 2022-12-28 Maxell, Ltd. Process and device for producing molded foam
US11241816B2 (en) 2015-07-08 2022-02-08 Maxell, Ltd. Process and device for producing molded foam
US11207809B2 (en) 2016-03-15 2021-12-28 Maxell, Ltd. Method and apparatus for manufacturing foam molded body
KR20190142427A (en) 2016-03-15 2019-12-26 마쿠세루 가부시키가이샤 Method and apparatus for manufacturing foam molded body
KR20200136053A (en) 2016-03-15 2020-12-04 마쿠세루 가부시키가이샤 Method and apparatus for manufacturing foam molded body
WO2018131372A1 (en) 2017-01-11 2018-07-19 マクセル株式会社 Method and apparatus for manufacturing foamed product
KR20190093638A (en) 2017-01-11 2019-08-09 마쿠세루 가부시키가이샤 Manufacturing method and apparatus for foam molding
US11318646B2 (en) 2017-01-11 2022-05-03 Maxell, Ltd. Method and apparatus for manufacturing foamed product
KR20190112808A (en) 2017-03-10 2019-10-07 마쿠세루 가부시키가이샤 Manufacturing method and apparatus for foam molding
US11478969B2 (en) 2017-03-10 2022-10-25 Maxell, Ltd. Manufacturing method and manufacturing device for foam molded article
US11820063B2 (en) 2017-03-10 2023-11-21 Maxell, Ltd. Manufacturing method and manufacturing device for foam molded article
KR20200021939A (en) 2017-06-26 2020-03-02 맥셀 홀딩스 가부시키가이샤 Method of manufacturing circuit components and circuit components
KR20200011486A (en) 2017-06-26 2020-02-03 마쿠세루 가부시키가이샤 Manufacturing method of foam molded article and foam molded article
KR20210084670A (en) 2017-06-26 2021-07-07 마쿠세루 가부시키가이샤 Method for manufacturing foam body and foam molded body
US11260564B2 (en) 2017-06-26 2022-03-01 Maxell, Ltd. Method for manufacturing foam molded body and foam molded body
WO2019003748A1 (en) 2017-06-26 2019-01-03 マクセル株式会社 Method for manufacturing foam molded body and foam molded body
US11945140B2 (en) 2017-06-26 2024-04-02 Maxell, Ltd. Method for manufacturing foam molded body and foam molded body
DE112022001487T5 (en) 2021-03-16 2024-01-04 Shibaura Machine Co., Ltd. Foam casting process, control method for an injection molding machine for foam casting, and injection molding machine for foam casting

Also Published As

Publication number Publication date
JPH10230528A (en) 1998-09-02

Similar Documents

Publication Publication Date Title
JP4144916B2 (en) Thermoplastic resin foam injection molded body and method for producing the same
US5997781A (en) Injection-expansion molded, thermoplastic resin product and production process thereof
JP4339296B2 (en) Method for producing thermoplastic resin foam injection molded article
JP3998374B2 (en) Method for adding supercritical carbon dioxide and method for producing thermoplastic resin foam using the addition method
KR100216396B1 (en) Process for preparing expanded product of thermoplastic resin
JP5497410B2 (en) Foam and production method thereof
KR101495452B1 (en) Polymer pellets containing supercritical fluid and methods of making and using
JP2007054993A (en) Injection foam molding method of thermoplastic resin
JP3655436B2 (en) Thermoplastic resin foam and method for producing the same
JP2002322288A (en) Method for producing thermoplastic resin composition
JPH0811190A (en) Production of thermoplastic resin foam
JPH1024436A (en) Thermoplastic resin foam and its manufacture
JPH10175249A (en) Thermoplastic resin foam and its manufacture
JP4002041B2 (en) Polyolefin composition foam and method for producing the same
JP2004017285A (en) Method for molding thin wall foamed molding, thin wall foamed molding and apparatus for molding foamed molding
JPH1024476A (en) Thermoplastic resin foam and its production
JP2008142997A (en) Method for manufacturing injection-foamed article and molding obtained by the method
JP2002321256A (en) Mold for foam injection molding and foamed molded product
CN110862569B (en) Preparation method of polypropylene foaming particles with low melt strength
JP2022539143A (en) POLYMER FOAM ARTICLES AND METHODS OF MAKING POLYMER FOAM
JP2003039512A (en) Thermoplastic resin foamed molded object
JPH10175248A (en) Thermoplastic resin foam and its manufacture
JP4113026B2 (en) Thermoplastic resin composition foamed molding method
CN113877004B (en) Biological bone nail material and preparation method thereof
JP2002240124A (en) Method for producing three-layered resin pipe

Legal Events

Date Code Title Description
A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20040210

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20040408

RD03 Notification of appointment of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7423

Effective date: 20040408

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20050810

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20051007

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20060510

RD13 Notification of appointment of power of sub attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7433

Effective date: 20060901

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A821

Effective date: 20060901

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20080617

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110627

Year of fee payment: 3

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120627

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120627

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130627

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130627

Year of fee payment: 5

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

LAPS Cancellation because of no payment of annual fees