JPH10175249A - Thermoplastic resin foam and its manufacture - Google Patents

Thermoplastic resin foam and its manufacture

Info

Publication number
JPH10175249A
JPH10175249A JP8339701A JP33970196A JPH10175249A JP H10175249 A JPH10175249 A JP H10175249A JP 8339701 A JP8339701 A JP 8339701A JP 33970196 A JP33970196 A JP 33970196A JP H10175249 A JPH10175249 A JP H10175249A
Authority
JP
Japan
Prior art keywords
thermoplastic resin
average cell
foam
inert gas
cells
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.)
Pending
Application number
JP8339701A
Other languages
Japanese (ja)
Inventor
Kaoru Yoda
馨 依田
Kozo Ichikawa
功三 市川
Shigeo Nishikawa
茂雄 西川
Haruo Inoue
晴夫 井上
Kiminobu Sueda
公宣 末田
Masao Eriguchi
真男 江里口
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 JP8339701A priority Critical patent/JPH10175249A/en
Publication of JPH10175249A publication Critical patent/JPH10175249A/en
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/375—Plasticisers, homogenisers or feeders comprising two or more stages
    • B29C48/39—Plasticisers, homogenisers or feeders comprising two or more stages a first extruder feeding the melt into an intermediate location of a second extruder
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
    • B29C48/375—Plasticisers, homogenisers or feeders comprising two or more stages
    • B29C48/385—Plasticisers, homogenisers or feeders comprising two or more stages using two or more serially arranged screws in separate barrels
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/25—Component parts, details or accessories; Auxiliary operations
    • B29C48/92—Measuring, controlling or regulating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2948/00—Indexing scheme relating to extrusion moulding
    • B29C2948/92—Measuring, controlling or regulating
    • B29C2948/92504—Controlled parameter
    • B29C2948/92704—Temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2948/00—Indexing scheme relating to extrusion moulding
    • B29C2948/92—Measuring, controlling or regulating
    • B29C2948/92819—Location or phase of control
    • B29C2948/92857—Extrusion unit
    • B29C2948/92876—Feeding, melting, plasticising or pumping zones, e.g. the melt itself
    • B29C2948/92895—Barrel or housing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C2948/00—Indexing scheme relating to extrusion moulding
    • B29C2948/92—Measuring, controlling or regulating
    • B29C2948/92819—Location or phase of control
    • B29C2948/92857—Extrusion unit
    • B29C2948/92904—Die; Nozzle zone

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Molding Of Porous Articles (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

PROBLEM TO BE SOLVED: To efficiently manufacture the thermoplastic resin foam of a cell which has beautiful surface appearance and a fine average cell diameter and a uniform average cell density by causing a mixture of respectively specific amounts of thermoplastic resin and organopolysiloxane at a specific temperature to foam with an inert gas in a supercritical state as a foaming agent. SOLUTION: A resin composition consisting of 100 pts.wt. of thermoplastic resin and 0.1-10 pts.wt. organopolysiloxane is melted at 100-400 deg.C in an extruder. Further, 0.1-30 pts.wt. of an inert gas in a supercritical state as a foaming agent are added for 100 pts.wt. of the thermoplastic resin composition to create a completely miscible state between the thermoplastic resin composition and the insert gas. Next, the temperature of the molten resin is reduced to 60-200 deg.C in the extruder while the pressure is maintained at a level higher than the critical pressure of the inert gas as the foaming agent. Thus it is possible to obtain a processing rate 1.2-2 times as much, compared to the case in which the thermoplastic resin alone which undergoes a foaming control step is used, in a die heated higher than the glass transition temperature of the resin.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、発泡剤として不活
性ガスを用いた微細な平均セル径と均一な平均セル密度
のセルを有する熱可塑性樹脂発泡体の製造方法および該
製造方法により製造される熱可塑性樹脂発泡体に関す
る。The present invention relates to a method for producing a thermoplastic resin foam having cells having a fine average cell diameter and a uniform average cell density using an inert gas as a foaming agent, and a method for producing the same. A thermoplastic resin foam.

【０００２】[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。化学
発泡法は、一般に原料ペレットと、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、微細な独立気泡を有す
る発泡体を得ることができる。しかし、これらの発泡体
は、コストが高いことに加えて、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。2. Description of the Related Art A method for producing a thermoplastic resin foam using a chemical foaming agent or a physical foaming agent is known. In general, the chemical foaming method is a method in which raw material pellets are mixed with a low-molecular-weight organic foaming agent that decomposes at a molding temperature to generate a gas, and the mixture is heated to a temperature equal to or higher than the decomposition temperature of the foaming agent. In this method, the generation of gas is sharp with respect to the decomposition temperature, the decomposition temperature can be easily adjusted by adding a foaming aid or the like, and a foam having fine closed cells can be obtained. However, these foams, in addition to their high cost, cause foam discoloration, odor generation, food hygiene problems, etc. due to the decomposition residue of the blowing agent remaining in the foam. In addition, there is also a problem of contamination of the molding machine due to the chemical foaming agent and defective molding associated therewith.

【０００３】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。On the other hand, in a gas foaming method which is a physical foaming method, a low-boiling organic compound such as butane, pentane or dichlorodifluoromethane is supplied to a resin melted in a molding machine and kneaded. This is a method of foam molding by discharging to a low pressure region. The low-boiling organic compound used in this method has a characteristic that it has an affinity for a resin and thus has excellent solubility and also has an excellent retention property, so that a high-magnification foam can be obtained. ing. However, in addition to the high cost, these foaming agents have dangers such as flammability and toxicity, and may cause air pollution problems. In addition, CFC-based gases such as dichlorodifluoromethane are moving toward total elimination due to environmental problems of depletion of the ozone layer.

【０００４】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、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、セル径
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。[0004] In order to solve the problems of the conventional methods, there have been proposed many methods using a clean and inexpensive inert gas such as carbon dioxide or nitrogen as a foaming agent. However, the inert gas has poor solubility because of its low affinity with the resin. For this reason, the foam has a large cell diameter, is non-uniform, and has a low cell density.
There were problems in mechanical strength, heat insulation, and expansion ratio.

【０００５】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、減圧を行い、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。以上の
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不可
能である。As a technique for solving these problems, US Pat. No. 4,473,665 describes a production method for obtaining a foam molded article in which fine cells having a diameter of 2 to 25 μm are uniformly dispersed. . In this method, first,
Under pressure, the inert gas is impregnated into the thermoplastic resin sheet until it is saturated. Then, after heating to the glass transition temperature of the thermoplastic resin, the pressure is reduced, the gas impregnated in the resin is supersaturated, the cell nucleus is generated, and the cell is rapidly cooled to control the cell growth. Or, in advance,
Extrusion molding and injection using a method in which a thermoplastic resin saturated with an inert gas under pressure is heated and melted, shaped under pressure, cooled and depressurized to generate cell nuclei, and cooled to control the cell diameter. A manufacturing method by molding is exemplified. 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 ten hours to completely impregnate the gas into the resin. And it is practically impossible to implement it industrially.

【０００６】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
流体は、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。この方法では、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。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. ing. Supercritical fluids have excellent solubility close to liquids and excellent diffusivity close to gases, so they have high solubility in resins and also have a high diffusion rate in resins. It becomes possible to impregnate the resin. In this method, a thermoplastic resin is formed into a sheet by an extruder, introduced into a pressurized chamber filled with carbon dioxide in a supercritical state, and impregnated with carbon dioxide in the sheet, and then heated in a foaming chamber under atmospheric pressure. A method of obtaining a foam by heating and foaming, and a step where a resin is melted by an extruder, impregnated with carbon dioxide in a supercritical state, and a molded body extruded into a sheet is introduced into a pressurizing chamber, and its pressure change is performed. A method has been proposed in which a cell nucleus is generated by heating, and the cell diameter and cell density are controlled by heating and cooling to obtain a foam.

【０００７】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有し、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、二酸化炭素の完全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。However, all of these methods require large-scale high-pressure equipment, require enormous equipment costs, have low work efficiency, and are difficult to industrialize. In addition, the former method has a long time to completely impregnate carbon dioxide into the molded article because the sheet-shaped molded article is directly impregnated, and the latter method impregnates the molten resin with the former method. Although the permeation rate of carbon dioxide is faster than the method, it is difficult to completely compatibilize carbon dioxide and generate many cell nuclei by kneading only one extruder. It was difficult to get.

【０００８】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
完全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製造方法を提案した。In Japanese Patent Application Laid-Open No. H8-11190, the present inventors impregnated a molten thermoplastic resin with an inert gas as a foaming agent using a first extruder and an adapter having a mixing section connected to the first extruder. A gas dissolving step for forming a completely compatible state of the thermoplastic resin and the inert gas; a cooling step for lowering the temperature of the molten resin while maintaining the pressurized state by the second extruder; The present invention has proposed a method for producing a thermoplastic resin foam having a fine and large number of cells uniformly, comprising a nucleus generation step of generating cell nuclei and a foaming control step of controlling cell diameter.

【０００９】この製造方法では、米国特許４４７３６６
５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。しかしながら本発明者らのさら
なる研究において、当該製造方法は押出加工品の生産速
度を上げると、外観不良が発生する傾向にあることが確
認されてきた。In this manufacturing method, US Pat.
According to the production methods described in Japanese Patent No. 5 and US Pat. No. 5,158,986, it is possible to continuously produce a foam which is substantially extremely difficult. However, further studies by the present inventors have confirmed that the production method tends to cause poor appearance when the production speed of an extruded product is increased.

【００１０】[0010]

【発明が解決しようとする課題】本発明は、美麗な表面
外観を有する、微細な平均セル径と均一な平均セル密度
のセルの熱可塑性樹脂発泡体を効率良く製造する方法
と、該製造方法により製造される熱可塑性樹脂発泡体を
提供するためになされたものである。DISCLOSURE OF THE INVENTION The present invention relates to a method for efficiently producing a thermoplastic resin foam having a fine average cell diameter and a uniform average cell density, which has a beautiful surface appearance, and the production method. The purpose of the present invention is to provide a thermoplastic resin foam produced by the method described above.

【００１１】[0011]

【課題を解決するための手段】本発明者らは、美麗な表
面外観を有する微細な平均セル径と均一な平均セル密度
のセルの熱可塑性樹脂発泡体について鋭意研究を重ねた
結果、熱可塑性樹脂とオルガノポリシロキサンの混合物
を超臨界状態の不活性ガスを発泡剤として発泡すること
で上記目的を達成することを見いだし本発明に到達し
た。Means for Solving the Problems The present inventors have conducted intensive studies on a thermoplastic resin foam having a fine average cell diameter and a uniform average cell density having a beautiful surface appearance. The present inventors have found that the above object can be achieved by foaming a mixture of a resin and an organopolysiloxane using an inert gas in a supercritical state as a blowing agent, and reached the present invention.

【００１２】すなわち本発明は、（１）押出機内で１０
０〜４００℃で熱可塑性樹脂１００重量部及びオルガノ
ポリシロキサン０．１〜１０重量部からなる樹脂組成物
を溶融し、発泡剤である超臨界状態の不活性ガスを熱可
塑性樹脂組成物１００重量部あたり０．１〜３０重量部
を添加し、熱可塑性樹脂組成物と不活性ガスの完全相溶
状態を形成するガス溶解工程、（２）押出機内で発泡剤
である不活性ガスの臨界圧力以上の圧力を維持したまま
溶融樹脂の温度を６０〜２００℃に下げる冷却工程、
（３）樹脂のガラス転移温度以上に加熱したダイス内に
おいて、不活性ガスの臨界圧力以上の圧力から最終的に
は大気圧へ圧力を解放することでセル核を発生させる核
生成工程、並びに（４）発泡体を熱可塑性樹脂のガラス
転移温度、または結晶化温度以下に冷却しセル径を制御
する発泡制御工程からなる熱可塑性樹脂を単独で使用し
た場合と比較して、１．２〜２倍の加工速度が得られ
る、微細な平均セル径と均一な平均セル密度のセルを有
する熱可塑性樹脂発泡体の製造方法およびその製造方法
により製造される熱可塑性樹脂発泡体に関するものであ
る。更には、平均セル径が０．０１〜５０μm、好まし
くは０．０１〜２０μmであり、平均セル密度が１０8〜
１０16個／cm3であることを特徴とする微細な平均セル
径と均一な平均セル密度のセルを有する熱可塑性樹脂発
泡体の製造方法と該製造方法により製造される熱可塑性
樹脂発泡体に関するものである。That is, the present invention relates to (1) a method in which 10
A resin composition comprising 100 parts by weight of a thermoplastic resin and 0.1 to 10 parts by weight of an organopolysiloxane is melted at 0 to 400 ° C., and an inert gas in a supercritical state as a foaming agent is added to the thermoplastic resin composition by 100 parts by weight. A gas dissolving step of adding 0.1 to 30 parts by weight per part to form a completely compatible state of the thermoplastic resin composition and the inert gas, (2) critical pressure of the inert gas as a foaming agent in the extruder A cooling step of lowering the temperature of the molten resin to 60 to 200 ° C. while maintaining the above pressure;
(3) a nucleation step of generating cell nuclei by releasing the pressure from a pressure higher than the critical pressure of the inert gas to finally the atmospheric pressure in a die heated to a temperature equal to or higher than the glass transition temperature of the resin; 4) The foam is cooled to below the glass transition temperature or crystallization temperature of the thermoplastic resin and the cell diameter is controlled by 1.2 to 2 in comparison with the case where the thermoplastic resin alone is used. The present invention relates to a method for producing a thermoplastic resin foam having cells having a fine average cell diameter and a uniform average cell density capable of obtaining a double processing speed, and a thermoplastic resin foam produced by the production method. Further, the average cell diameter is 0.01 to 50 μm, preferably 0.01 to 20 μm, and the average cell density is 10 8 to
The present invention relates to a method for producing a thermoplastic resin foam having cells having a fine average cell diameter and a uniform average cell density characterized by being 10 16 cells / cm 3 , and a thermoplastic resin foam produced by the production method. Things.

【００１３】[0013]

【発明実施の形態】本発明に用いられる熱可塑性樹脂と
しては、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）、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、スチレン系樹脂が好ましく、特にポリスチレンが
好ましい。スチレン系樹脂としては、スチレン系単量体
からなる単独重合体あるいは所望により他の単量体との
共重合体が含まれ、一般に市場で容易に入手できるもの
が使用でき、その製造方法は文献に多く記載されてい
る。スチレン系単量体としてはスチレン、α−メチルス
チレン、α−エチルスチレンのような側鎖アルキル置換
スチレン、ビニルトルエン、ｐ−メチルスチレンのよう
な該アルキル置換スチレン、モノクロルスチレン、ジク
ロルスチレン、トリブロモスチレン、テトラブロムスチ
レン等のハロゲン化スチレン等が挙げられ、特に好まし
くはスチレン及びα−メチルスチレンである。かかるス
チレン系単量体の少なくとも一種が用いられる。また所
望に応じてアクリロニトリル、メタアクリロニトリル、
フマロニトリル等のアクリロニトリル系単量体、マレイ
ミド、Ｎ−フェニルマレイミド等のマレイミド系単量
体、アクリル酸メチル、メタクリル酸メチル等のアクリ
ル酸エステル系単量体、マレイン酸、無水マレイン酸等
のマレイン酸系単量体等も前記スチレン系単量体と共重
合させてもよい。BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic resin used in the present invention includes styrene resins (for example, polystyrene, butadiene / styrene copolymer, acrylonitrile / styrene copolymer, acrylonitrile / butadiene / styrene copolymer, etc.). , 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, poly Butylene terephthalate),
Biodegradable polyester resin (for example, hydroxycarboxylic acid condensate such as polylactic acid, condensate of diol and dicarboxylic acid such as polybutylene succinate) polyamide resin, polyimide resin, fluororesin, polysulfone, polyethersulfone , Polyarylate, polyetheretherketone, liquid crystal polymer, etc.
Mixtures of more than one species. Among these thermoplastic resins, styrene resins are preferred, and polystyrene is particularly preferred. The styrene-based resin includes a homopolymer composed of a styrene-based monomer or a copolymer with another monomer if desired, and generally can be easily obtained on the market. Many have been described. Styrene-based monomers include side-chain alkyl-substituted styrenes such as styrene, α-methylstyrene and α-ethylstyrene, alkyl-substituted styrenes such as vinyltoluene and p-methylstyrene, monochlorostyrene, dichlorostyrene and trichlorostyrene. Examples thereof include halogenated styrenes such as bromostyrene and tetrabromostyrene, and particularly preferred are styrene and α-methylstyrene. At least one of such styrene monomers is used. Acrylonitrile, methacrylonitrile,
Acrylonitrile monomers such as fumaronitrile, maleimide monomers such as maleimide and N-phenylmaleimide, acrylate monomers such as methyl acrylate and methyl methacrylate, and maleic acid such as maleic acid and maleic anhydride A system monomer or the like may be copolymerized with the styrene monomer.

【００１４】また、前記スチレン系樹脂はゴム質重合体
の存在下に重合させることでゴムがグラフトされたグラ
フト重合体とすることも可能であり、ゴム質重合体とし
ては、スチレン−ブタジエン共重合体、ブタジエン−ア
クリロニトリル共重合体、エチレン−プロピレン−ジエ
ン共重合体、ブタジエン−アクリル酸エステル共重合体
等が挙げられる。スチレン系樹脂は塊状重合法、懸濁重
合法、乳化重合法等の公知の方法によって得られる。The styrenic resin may be polymerized in the presence of a rubbery polymer to form a graft polymer obtained by grafting rubber. The rubbery polymer may be a styrene-butadiene copolymer. Coalition, butadiene-acrylonitrile copolymer, ethylene-propylene-diene copolymer, butadiene-acrylate copolymer and the like. The styrene resin can be obtained by a known method such as a bulk polymerization method, a suspension polymerization method, and an emulsion polymerization method.

【００１５】本発明に使用される熱可塑性樹脂には特に
制限はないが、ＪＩＳ Ｋ７２１０に定められたメルト
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０．２〜２０
g/10分の範囲にあることが好ましい。メルトフローイン
デックスが０．０５g/10分未満においては、溶融時の樹
脂粘度が高すぎ、押出機の負荷が過大となって、加工が
困難となる傾向がある。また６０g/10分を超える場合に
おいては、樹脂が発泡時のガス圧に耐えるだけの粘度を
保持できず、破泡を生じ微小なセルを生成することが不
可能となる。The thermoplastic resin used in the present invention is not particularly limited, but has a melt flow index specified in JIS K7210 of 0.05 to 60 g / 10 min, preferably 0.1 to 40 g / 10 min. More preferably, 0.2 to 20
It is preferably in the range of g / 10 minutes. If the melt flow index is less than 0.05 g / 10 minutes, the viscosity of the resin at the time of melting is too high, and the load on the extruder tends to be excessive, so that processing tends to be difficult. If it exceeds 60 g / 10 minutes, the resin cannot maintain a viscosity enough to withstand the gas pressure at the time of foaming, so that foam is broken and it becomes impossible to form minute cells.

【００１６】熱可塑性樹脂として、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。When a thermoplastic resin having a melt flow index of 10 to 60 g / 10 minutes is used, it is easy to obtain a high magnification product. When a melt flow index having a melt flow index of 0.05 to 10 g / 10 minutes is used, the cooling time is shortened due to rapid cooling and solidification, and the effect of improving productivity is produced.

【００１７】本発明に用いられる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、および／または、これら
オルガノポリシロキサンが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によって変性
された変性オルガノポリシロキサンが挙げられる。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。The organopolysiloxane used in the present invention may be polydimethylsiloxane, polydiphenylsiloxane, polymethylphenylsiloxane, polymethylhydrogensiloxane, and / or an epoxy group-containing compound or an amino group-containing compound. Modified organopolysiloxane modified with a compound or an ester bond-containing compound is exemplified. Among them, polydimethylsiloxane is preferred from the viewpoints of dispersibility in a resin, solubility, and effects of improving the surface appearance.

【００１８】オルガノポリシロキサンの添加量は熱可塑
性樹脂１００重量部あたり、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。オルガノポリシロキ
サンの添加量が、０．１重量部未満においては、表面外
観改良の効果が乏しく、また１０重量部以上よりも多い
場合には、樹脂が発泡時のガス圧に耐えるだけの粘度を
保持できず、破泡を生じ微小なセルを生成することが不
可能となるため好ましくない。The addition amount of the organopolysiloxane is in the range of 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, more preferably 0.3 to 5 parts by weight, per 100 parts by weight of the thermoplastic resin. Is preferred. When the amount of the organopolysiloxane is less than 0.1 part by weight, the effect of improving the surface appearance is poor, and when the amount is more than 10 parts by weight, the resin has a viscosity sufficient to withstand the gas pressure during foaming. This is not preferable because it cannot be held, and it becomes impossible to generate fine cells due to foam breakage.

【００１９】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。When a modified organopolysiloxane is used, the compatibility with the resin can be improved by adding a radical generator such as a peroxide.

【００２０】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
ることが可能だが、無機微粉末としては、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。無機微粉末の粒径は５０μm
以下である必要があり、好ましくは１０μm以下、さら
に好ましくは５μm以下である。In the present invention, an inorganic fine powder acting 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, and magnesium oxide. , Zinc oxide, glass beads, glass powder, titanium oxide, carbon black, anhydrous silica and the like, preferably talc,
Calcium carbonate, titanium oxide and anhydrous silica are preferred, and talc is particularly preferred. Particle size of inorganic fine powder is 50μm
It is necessary to be not more than 10 μm, preferably not more than 10 μm, more preferably not more than 5 μm.

【００２１】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。The above-mentioned resin composition contains the inorganic fine powder exemplified in the composition as long as the properties of the present invention are not impaired.
In addition to aliphatic carboxylic acids and derivatives thereof, ethylene-propylene rubber, ethylene-butene rubber, propylene-butene rubber, hydrogenated styrene-butadiene diblock copolymer, hydrogenated styrene-butadiene-styrene triblock copolymer, Hydrogenated styrene-isoprene diblock copolymer, styrene-isoprene-
Hydrogenated styrene triblock copolymer, low-density polyethylene, high-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, polybutene, etc. Various elastomers, plasticizers, pigments, stabilizers, fillers, metal powders, and the like can be appropriately used depending on the purpose and application.

【００２２】本発明の熱可塑性樹脂発泡体の原料となる
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。すなわ
ち、熱可塑性樹脂とオルガノポリシロキサンを高速攪拌
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を均一混合した状態で使
用することも差し支えない。The method for producing the thermoplastic resin composition used as the raw material of the thermoplastic resin foam of the present invention is not particularly limited, and a generally known method can be employed. That is, after uniformly mixing the thermoplastic resin and the organopolysiloxane with a high-speed stirrer or the like, it can be manufactured by a method of melt-kneading with a single-screw or multi-screw extruder having sufficient kneading ability, a mixing roll, a kneader, a Brabender, or the like. . Further, the thermoplastic resin and the organopolysiloxane may be used in a uniformly mixed state.

【００２３】本発明に発泡剤として用いられる不活性ガ
スとしては、二酸化炭素、窒素、アルゴン、ヘリウム等
が挙げられるがこれらに限定されない。また、これら単
独でも２種以上の混合物でも使用できる。これらのガス
の中でも、安全性、熱可塑性樹脂への浸透性の点から考
慮して、二酸化炭素および窒素が好ましく、二酸化炭素
が特に好ましい。The inert gas used as a foaming agent in the present invention includes, but is not limited to, carbon dioxide, nitrogen, argon, helium and the like. Further, these may be used alone or in combination of two or more. Among these gases, carbon dioxide and nitrogen are preferred, and carbon dioxide is particularly preferred, in view of safety and permeability to the thermoplastic resin.

【００２４】また不活性ガスの量は、熱可塑性樹脂とオ
ルガノポリシロキサンとの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。不活性ガス
が０．１重量部以下では微細なセル径は得られず、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。The amount of the inert gas is 0.1 to 30 parts by weight, more preferably 0.2 to 20 parts by weight, based on 100 parts by weight of the thermoplastic resin composition of the thermoplastic resin and the organopolysiloxane. It is preferred that If the inert gas content is 0.1 parts by weight or less, a fine cell diameter cannot be obtained, and if the inert gas is 30 parts by weight or more, a water-swelling appearance defect occurs on the foam surface, and it is difficult to obtain a beautiful surface appearance.

【００２５】押出機内で樹脂組成物の溶融物中に不活性
ガスを混合する方法としては、例えば気体状態の不活性
ガスを直接あるいは加圧または減圧した状態で注入する
方法、液体状態の不活性ガス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。これら不活性ガスは、溶
融樹脂中への溶解性、浸透性、拡散性等の観点から、押
出機内部で超臨界状態となっている必要がある。As a method of mixing an inert gas into a melt of a resin composition in an extruder, for example, a method of injecting a gaseous inert gas directly or under a pressurized or reduced pressure, a method of injecting a liquid inert gas There is a method of injecting gas with a plunger pump or the like. These inert gases need to be in a supercritical state inside the extruder from the viewpoint of solubility, permeability, diffusibility and the like in the molten resin.

【００２６】本発明における熱可塑性樹脂、オルガノポ
リシロキサン及び不活性ガスの完全相溶状態を形成する
ガス溶解工程とは、第１押出機内で樹脂を加熱溶融した
のち、該溶融樹脂組成物中に超臨界状態の不活性ガスを
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第２押出機で冷却し、発泡に
適した粘度になる様調整する工程であり、核生成工程と
は、ダイス内で加圧下より圧力低下させ、セル核を発生
させる工程であり、発泡制御工程とは、冷却によりセル
の成長を制御することでセル径の大きさを制御する工程
である。これらの工程は、特開平８−１１１９０号公報
記載の方法に準じて行う。The gas dissolving step for forming a completely compatible state of the thermoplastic resin, the organopolysiloxane and the inert gas in the present invention includes the step of heating and melting the resin in the first extruder and then adding the molten resin to the molten resin composition. This is a step of adding an inert gas in a supercritical state and mixing uniformly, and the cooling step is to cool the resin composition in a molten state with a second extruder and adjust the resin composition to a viscosity suitable for foaming. The nucleation step is a step of generating a cell nucleus by lowering the pressure in a die from under pressure, and the foaming control step is a step of controlling the growth of the cell by cooling to increase the cell diameter. Is a step of controlling These steps are performed according to the method described in JP-A-8-11190.

【００２７】本発明の一例を説明する。ガス溶解工程に
おいて熱可塑性樹脂１００重量部とオルガノポリシロキ
サン０．１〜１０重量部からなる熱可塑性樹脂の組成物
あるいは混合物を、ホッパーよりタンデム式発泡押出成
形機の第１押出機中に供給し、加熱溶融させる。また、
不活性ガスは、ガスボンベより昇圧ポンプに輸送、昇圧
され、圧力、温度の制御を行い、第１押出機内の溶融し
た樹脂組成物中に供給される。このとき、第１押出機内
に存在する不活性ガスが、樹脂に対する溶解拡散を大幅
に高め、短時間で樹脂中に浸透することを可能とする臨
界圧力以上で、臨界温度以上の超臨界状態である必要が
ある。例えば、二酸化炭素の場合、臨界圧力は７５．３
kg/cm2、臨界温度は３１．３５℃であり、第１押出機内
は、圧力は７５〜４００kg/cm2、好ましくは１００〜３
００kg/cm2の範囲である。温度は１００〜４００℃、好
ましくは１７０〜２８０℃の範囲が好ましい。第１押出
機内に供給する不活性ガスは、第１押出機に供給後、昇
温、昇圧され超臨界状態となる、あるいは第１押出機に
供給される以前に昇温、昇圧され超臨界状態となってか
ら供給しても構わない。An example of the present invention will be described. In the gas dissolving step, a thermoplastic resin composition or mixture consisting of 100 parts by weight of the thermoplastic resin and 0.1 to 10 parts by weight of the organopolysiloxane is supplied from a hopper into a first extruder of a tandem type foam extruder. , Heat and melt. Also,
The inert gas is transported from the gas cylinder to the pressure boosting pump, is pressurized, controls the pressure and temperature, and is supplied into the molten resin composition in the first extruder. At this time, the inert gas present in the first extruder greatly increases the dissolution and diffusion to the resin, and is in a supercritical state at a critical pressure or higher at a critical pressure or higher that allows the permeation into the resin in a short time. Need to be. For example, in the case of carbon dioxide, the critical pressure is 75.3.
kg / cm 2 , the critical temperature is 31.35 ° C., and the pressure in the first extruder is 75 to 400 kg / cm 2 , preferably 100 to 3 kg / cm 2 .
The range is 00 kg / cm 2 . The temperature is preferably in the range of 100-400C, preferably 170-280C. The inert gas supplied into the first extruder is heated and pressurized to a supercritical state after being supplied to the first extruder, or is heated and pressurized before being supplied to the first extruder to be in a supercritical state It may be supplied after that.

【００２８】第１押出機のバレル中で不活性ガスと溶融
した樹脂組成物とがスクリュウにより混練される。次に
冷却工程において熱可塑性樹脂組成物に対する不活性ガ
スの溶解性を高めるため、混合溶融体を、第２押出機へ
と送入し、圧力を維持したまま発泡に適した温度まで下
げていく。このときの温度は、６０〜２００℃好ましく
は８０〜１８０℃である。この第２押出機を用いた冷却
工程は、セルに適した温度条件に無理なく近づけるため
の工程である。この工程で十分に冷却することにより、
連続的かつ安定的に、本発明の熱可塑性樹脂発泡体の製
造が可能となる。ただし第１押出機だけで該溶融体を発
泡に適した温度まで十分に冷却可能な場合においては、
第２押出機を連結することなく製造することが可能であ
る。また該溶融体の不活性ガスの溶解状態を向上させる
ために、第１押出機と第２押出機の間にスタティックミ
キサー等の混練部を接続しておくことも可能である。In the barrel of the first extruder, the inert gas and the molten resin composition are kneaded by a screw. Next, in order to increase the solubility of the inert gas in the thermoplastic resin composition in the cooling step, the mixed melt is fed into the second extruder, and the temperature is reduced to a temperature suitable for foaming while maintaining the pressure. . The temperature at this time is 60 to 200 ° C, preferably 80 to 180 ° C. The cooling step using the second extruder is a step for reasonably approaching a temperature condition suitable for the cell. By cooling sufficiently in this process,
It is possible to continuously and stably produce the thermoplastic resin foam of the present invention. However, when the melt can be sufficiently cooled to a temperature suitable for foaming only by the first extruder,
It is possible to manufacture without connecting the second extruder. Further, in order to improve the dissolution state of the inert gas in the melt, it is possible to connect a kneading unit such as a static mixer between the first extruder and the second extruder.

【００２９】次に核生成工程として該溶融体をダイスに
おいて、最終的には大気圧に解放することで急激な圧力
低下を生じさせ、不活性ガスを過飽和状態にする。過飽
和状態になった該溶融体は、多数のセル核を発生させ
る。また、一般的にガスが含まれている樹脂のガラス転
移温度は、ガスの含浸量に比例して、低下することが知
られているが、ダイス内の温度は、ガスが含浸した樹脂
のガラス転移温度以上であることが好ましい。この核生
成した発泡体をシート状等、任意の形状に賦形して押出
する。Next, as a nucleation step, the molten material is finally released to the atmospheric pressure in a die, thereby causing a rapid pressure drop, thereby bringing the inert gas into a supersaturated state. The supersaturated melt generates many cell nuclei. It is generally known that the glass transition temperature of a resin containing a gas decreases in proportion to the gas impregnation amount. It is preferred that the temperature is higher than the transition temperature. The nucleated foam is shaped into an arbitrary shape such as a sheet and extruded.

【００３０】次に発泡制御工程としてこの発泡体を速や
かに、樹脂のガラス転移温度あるいは結晶化温度以下に
冷却して、発生したセルの成長を制御し、平均セル径が
０．０１〜５０μm、好ましくは０．０１〜２０μm、平
均セル密度が１０8〜１０16個／cm3である、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熱可塑性樹
脂発泡体を得る。Next, as a foam control step, the foam is immediately cooled to a temperature lower than the glass transition temperature or crystallization temperature of the resin to control the growth of the generated cells, and the average cell diameter is 0.01 to 50 μm. A thermoplastic resin foam having a fine average cell diameter and a uniform average cell density of preferably 0.01 to 20 μm and an average cell density of 10 8 to 10 16 cells / cm 3 is obtained.

【００３１】なお本発明により美麗な表面外観を有す
る、微細な平均セル径と均一な平均セル密度のセルを有
する熱可塑性樹脂発泡体が得られるのは、以下の理由に
よるものと推定される。熱可塑性樹脂とオルガノポリシ
ロキサンの混合物を溶融したところに不活性ガスを添加
し、均一に混合された樹脂組成物は、押出機先端のダイ
ス内を流動する際に、オルガノポリシロキサンが、溶融
樹脂とダイス等の金属部との界面に高濃度に存在するこ
ととなり、潤滑剤としての効果を発現することから、美
麗な表面外観になると推定される。また従来法と比較し
表面外観が良好になり易いため、吐出速度を速くするこ
とが可能となり、熱可塑性樹脂単独に比べて、１．２〜
２倍の加工速度を得ることが可能となる。本発明によ
り、美麗な表面外観を有する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熱可塑性樹脂発泡体を効率
良く製造することが可能になる。It is presumed that the thermoplastic resin foam having a fine average cell diameter and a uniform average cell density having a beautiful surface appearance according to the present invention is obtained for the following reasons. When the mixture of the thermoplastic resin and the organopolysiloxane is melted, an inert gas is added thereto, and the uniformly mixed resin composition flows into the die at the tip of the extruder. It exists at a high concentration at the interface between the metal part and a metal part such as a die, and exhibits an effect as a lubricant. In addition, since the surface appearance is easily improved as compared with the conventional method, it is possible to increase the discharge speed, which is 1.2 to less than the thermoplastic resin alone.
It is possible to obtain twice the processing speed. According to the present invention, it is possible to efficiently produce a thermoplastic resin foam having cells having a fine average cell diameter and a uniform average cell density having a beautiful surface appearance.

【００３２】[0032]

【実施例】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。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。 １）表面外観 発泡体の表面を目視観察し、一様で均一な場合を○、水
膨れ状の膨れがある等表面外観が一様ではない場合を×
とした。 ２）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。 ３）平均セル密度 連続的に熱可塑性樹脂発泡体を押し出し、１０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５００μ
m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。 ４）セルの均一性 走査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。EXAMPLES The present invention will be described below with reference to examples, but the contents of the present invention are not limited to these examples. The evaluation of physical properties described in Examples and Comparative Examples was performed according to the following methods. 1) Surface appearance The surface of the foam was visually observed, and the case where the surface appearance was uniform and uniform was evaluated as good.
And 2) Cell Diameter A photograph taken by a scanning electron microscope was subjected to image processing, and the obtained circle equivalent diameter of the cell was defined as the average diameter of the cell. 3) Average cell density The thermoplastic resin foam was continuously extruded, and three samples were obtained every 10 samples. Photographs of three samples were taken with a scanning electron microscope, and the photographs were image-processed to 500 μm.
The number of cells per 1 cm 2 was calculated from the number of cells in m squares, and a value obtained by raising the value to the third power was defined as a cell density, and an average of three points was defined as an average cell density. 4) Uniformity of cells The maximum cell diameter in a 500 μm square photograph taken by a scanning microscope is not more than twice the average cell diameter, and the measured cell density at three points is の of the average cell density. The case of 以内 2 times or less was evaluated as ○, and the others were evaluated as ×.

【００３３】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より第１押出機（口径
２０mm、Ｌ／Ｄ＝３０）に供給し、シリンダー設定温度
２２０℃で加熱溶融させた。また、発泡剤である二酸化
炭素をプランジャーポンプにて１８０kg/cm2に昇圧し、
完全に溶融した該樹脂１００重量部に対して、二酸化炭
素を１０重量部の割合で溶解させた。十分に溶融樹脂と
二酸化炭素を混練溶解させ、続いて第２押出機（口径３
０mm、Ｌ／Ｄ＝３０）へと送入し、徐々に温度を下げて
いった。このとき、第２押出機先端の設定温度を１１０
℃とした。続いて該溶融体を１００℃に設定した、ダイ
スで減圧し厚さ３mmのシート状になる様、サイジング装
置で賦形した発泡体として押し出した。得られた樹脂発
泡シートの厚みは３mmであった。このとき吐出量は、５
kg/hに設定していたが、コルゲーションあるいはメルト
フラクチャー等による表面外観の不良が生じることはな
く、連続的に良外観製品を製造することが可能であっ
た。発泡体の評価の結果を表１に示す。表面外観良好、
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
発泡体であった。Example 1 The melt flow index at 200 ° C. and 5 kg was 2.
6g / 10min polystyrene resin (Mitsui Toatsu Chemical Co., Ltd.)
1 part by weight of polydimethylsiloxane is dry-blended with 100 parts by weight of pellets manufactured by Topolex 555-57), and the mixture is supplied from a hopper to a first extruder (diameter 20 mm, L / D = 30), and It was heated and melted at a set temperature of 220 ° C. Also, the pressure of carbon dioxide as a foaming agent was increased to 180 kg / cm 2 by a plunger pump,
Carbon dioxide was dissolved at a ratio of 10 parts by weight with respect to 100 parts by weight of the completely melted resin. The molten resin and carbon dioxide are sufficiently kneaded and dissolved, and then the second extruder (with a diameter of 3
0 mm, L / D = 30), and the temperature was gradually lowered. At this time, the set temperature at the tip of the second extruder is set to 110
° C. Subsequently, the melt was extruded as a foam formed by a sizing apparatus so as to form a sheet having a thickness of 3 mm by reducing the pressure with a die set at 100 ° C. The thickness of the obtained resin foam sheet was 3 mm. At this time, the discharge amount is 5
Although it was set to kg / h, there was no occurrence of poor surface appearance due to corrugation or melt fracture, and it was possible to continuously produce good appearance products. Table 1 shows the results of the evaluation of the foam. Good surface appearance,
It was a foam having cells with a fine average cell diameter and a uniform average cell density.

【００３４】実施例２ 実施例１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１に従い発泡体を得た。発泡体の
評価の結果を表１に示す。表面外観良好、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体であっ
た。Example 2 A foam was obtained in the same manner as in Example 1 except that 2 parts by weight of talc having an average particle diameter of 2 μm was added in addition to the polystyrene resin and polydimethylsiloxane. Table 1 shows the results of the evaluation of the foam. The foam had good surface appearance, fine average cell diameter, and cells having a uniform average cell density.

【００３５】実施例３〜６ 実施例１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１に示した割合と
した以外は、実施例１に従い発泡体を得た。発泡体の評
価の結果を表１に示す。表面外観良好、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体であっ
た。Examples 3 to 6 A foam was obtained in the same manner as in Example 1 except that the proportions of polystyrene resin, polydimethylsiloxane and carbon dioxide were changed to the proportions shown in Table 1. Table 1 shows the results of the evaluation of the foam. The foam had good surface appearance, fine average cell diameter, and cells having a uniform average cell density.

【００３６】実施例７ 実施例１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１に従い発泡
体を得た。発泡体の評価の結果を表１に示す。表面外観
良好、微細な平均セル径と均一な平均セル密度のセルを
有する発泡体であった。Example 7 In Example 1, the polystyrene resin was heated at 200 ° C. and 5 kg.
A foam was obtained in accordance with Example 1 except that a polystyrene resin having a melt flow index of 10 g / 10 min (TOPOLEX 525-51, manufactured by Mitsui Toatsu Chemicals, Inc.) was used. Table 1 shows the results of the evaluation of the foam. The foam had good surface appearance, fine average cell diameter, and cells having a uniform average cell density.

【００３７】実施例８ 実施例１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１に従い発泡
体を得た。発泡体の評価の結果を表１に示す。表面外観
良好、微細な平均セル径と均一な平均セル密度のセルを
有する発泡体であった。Example 8 The procedure of Example 1 was repeated except that the polystyrene resin was heated at 200 ° C. and 5 kg.
A foam was obtained according to Example 1, except that the polystyrene resin (Topolex 575-57, manufactured by Mitsui Toatsu Chemicals, Inc.) having a melt flow index of 1.8 g / 10 min. Table 1 shows the results of the evaluation of the foam. The foam had good surface appearance, fine average cell diameter, and cells having a uniform average cell density.

【００３８】比較例１ 実施例１において、ポリジメチルシロキサンを添加せ
ず、ポリスチレン樹脂のみを使用した以外は、実施例１
に従い発泡体を得た。発泡体の評価の結果を表２に示
す。吐出量３kg/hでは良外観品を得ることが可能であっ
たが、３．５kg/h以上では、コルゲーションあるいはメ
ルトフラクチャー等による表面外観の不良が生じ、良外
観品の取得は不可能であり、ポリジメチルシロキサンの
添加がない場合においては、本発明の目的である発泡体
の効率良い発泡体の製造方法の範疇には該当しない。Comparative Example 1 Example 1 was repeated except that no polydimethylsiloxane was added and only a polystyrene resin was used.
To obtain a foam. Table 2 shows the results of the evaluation of the foam. With a discharge rate of 3 kg / h, it was possible to obtain a good-looking product, but at a rate of 3.5 kg / h or more, poor surface appearance due to corrugation or melt fracture occurred, making it impossible to obtain a good-looking product. In the case where polydimethylsiloxane is not added, the present invention does not fall under the category of a method for efficiently producing a foam.

【００３９】比較例２〜４ 実施例１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１に示した割合と
した以外は、実施例１に従い発泡体を得た。発泡体の評
価の結果を表２に示す。表面外観不良、微細なセルでは
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。Comparative Examples 2 to 4 A foam was obtained in the same manner as in Example 1 except that the proportions of polystyrene resin, polydimethylsiloxane and carbon dioxide were changed to the proportions shown in Table 1. Table 2 shows the results of the evaluation of the foam. It is not preferable in terms of poor surface appearance, not fine cells, small number of cells, and the like, and the foam intended in the present invention could not be produced.

【００４０】[0040]

【表１】 [Table 1]

【００４１】[0041]

【表２】 [Table 2]

【００４２】[0042]

【表３】 [Table 3]

【００４３】[0043]

【発明の効果】本発明により、美麗な表面外観を有す
る、微細な平均セル径と均一な平均セル密度のセルを有
する熱可塑性樹脂発泡体を、効率良く製造することが可
能となる。According to the present invention, it is possible to efficiently produce a thermoplastic resin foam having a fine surface appearance, a fine average cell diameter and cells having a uniform average cell density.

【図面の簡単な説明】[Brief description of the drawings]

【図１】 本発明の熱可塑性樹脂発泡体の製造方法の一
例を示す概略構成図。FIG. 1 is a schematic configuration diagram showing an example of a method for producing a thermoplastic resin foam of the present invention.

【符号の説明】[Explanation of symbols]

（１）第１押出機 （２）連結部 （３）第２押出機 （４）ダイス （５）サイジング装置 （６）ホッパー （７）ガスボンベ （８）昇圧ポンプ （９）スクリュウ （１０）発泡シート (1) First extruder (2) Connecting part (3) Second extruder (4) Die (5) Sizing device (6) Hopper (7) Gas cylinder (8) Boost pump (9) Screw (10) Foam sheet

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ // Ｂ２９Ｋ 83:00 101:12 105:04 (72)発明者 井上 晴夫 神奈川県横浜市栄区笠間町1190番地 三井 東圧化学株式会社内 (72)発明者 末田 公宣 神奈川県横浜市栄区笠間町1190番地 三井 東圧化学株式会社内 (72)発明者 江里口 真男 神奈川県横浜市栄区笠間町1190番地 三井 東圧化学株式会社内──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 6 Identification symbol FI // B29K 83:00 101: 12 105: 04 (72) Inventor Haruo Inoue 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemicals (72) Inventor Kiminobu Sueda 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Masao Eriguchi 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (4)

【特許請求の範囲】[Claims] 【請求項１】 （１）押出機内で１００〜４００℃で熱
可塑性樹脂１００重量部及びオルガノポリシロキサン
０．１〜１０重量部からなる樹脂組成物を溶融し、発泡
剤である超臨界状態の不活性ガスを熱可塑性樹脂組成物
１００重量部あたり０．１〜３０重量部を添加し、熱可
塑性樹脂組成物と不活性ガスの完全相溶状態を形成する
ガス溶解工程、（２）押出機内で発泡剤である不活性ガ
スの臨界圧力以上の圧力を維持したまま溶融樹脂の温度
を６０〜２００℃に下げる冷却工程、（３）樹脂のガラ
ス転移温度以上に加熱したダイス内において、不活性ガ
スの臨界圧力以上の圧力から最終的には大気圧へ圧力を
解放することでセル核を発生させる核生成工程、並びに
（４）発泡体を熱可塑性樹脂のガラス転移温度、または
結晶化温度以下に冷却しセル径を制御する発泡制御工程
からなり、熱可塑性樹脂を単独で使用した場合と比較し
て１．２〜２倍の加工速度が得られる、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熱可塑性樹脂発
泡体の製造方法。1. (1) A resin composition comprising 100 parts by weight of a thermoplastic resin and 0.1 to 10 parts by weight of an organopolysiloxane is melted in an extruder at 100 to 400 ° C., and a supercritical state as a foaming agent is melted. A gas dissolving step of adding 0.1 to 30 parts by weight of an inert gas per 100 parts by weight of the thermoplastic resin composition to form a completely compatible state of the thermoplastic resin composition and the inert gas, (2) inside the extruder (3) a cooling step of lowering the temperature of the molten resin to 60 to 200 ° C. while maintaining the pressure equal to or higher than the critical pressure of the inert gas as the foaming agent; A nucleation step of generating cell nuclei by releasing the pressure from the pressure higher than the critical pressure of the gas to the atmospheric pressure, and (4) converting the foamed body to a temperature lower than the glass transition temperature or the crystallization temperature of the thermoplastic resin. Cooling The cell diameter is controlled by a foaming control step, and a processing speed of 1.2 to 2 times is obtained as compared with the case where the thermoplastic resin is used alone. The fine average cell diameter and the uniform average cell density are obtained. A method for producing a thermoplastic resin foam having cells. 【請求項２】 微細な平均セル径が０．０１〜５０μm
であり、均一な平均セル密度が１０8〜１０16個／cm3で
ある請求項１記載の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熱可塑性樹脂発泡体の製造方法。2. A fine average cell diameter of 0.01 to 50 μm.
The method for producing a thermoplastic resin foam having cells having a fine average cell diameter and a uniform average cell density according to claim 1, wherein the uniform average cell density is 10 8 to 10 16 cells / cm 3 . 【請求項３】 微細な平均セル径が０．０１〜２０μm
であり、均一な平均セル密度が１０8〜１０16個／cm3で
ある請求項１記載の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熱可塑性樹脂発泡体の製造方法。3. A fine average cell diameter of 0.01 to 20 μm.
The method for producing a thermoplastic resin foam having cells having a fine average cell diameter and a uniform average cell density according to claim 1, wherein the uniform average cell density is 10 8 to 10 16 cells / cm 3 . 【請求項４】 請求項１、２又は３記載の製造方法によ
り製造される微細な平均セル径と均一な平均セル密度の
セルを有する熱可塑性樹脂発泡体。4. A thermoplastic resin foam having cells having a fine average cell diameter and a uniform average cell density produced by the production method according to claim 1, 2 or 3.
JP8339701A 1996-12-19 1996-12-19 Thermoplastic resin foam and its manufacture Pending JPH10175249A (en)

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WO2001005569A1 (en) * 1999-07-16 2001-01-25 Wavin B.V. Method for forming an article comprising closed-cell microfoam from thermoplastic
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WO2001005569A1 (en) * 1999-07-16 2001-01-25 Wavin B.V. Method for forming an article comprising closed-cell microfoam from thermoplastic
JP2001232742A (en) * 2000-02-22 2001-08-28 Dainippon Printing Co Ltd Decorative sheet
WO2003014204A1 (en) * 2001-08-08 2003-02-20 Idemitsu Petrochemical Co., Ltd. Foamed article, method for production thereof and reflecting plate
JP2003049018A (en) * 2001-08-08 2003-02-21 Idemitsu Petrochem Co Ltd Foam, method for producing the same and reflection plate
JP2008163117A (en) * 2006-12-27 2008-07-17 Kao Corp Manufacturing method for foaming thermoplastic resin
JP2010077180A (en) * 2008-09-24 2010-04-08 Toray Ind Inc Polylactic acid foamed article and method for manufacturing the same
JP2010138391A (en) * 2008-11-14 2010-06-24 Mitsui Chemicals Inc Foam and production method of the same
WO2010101291A1 (en) * 2009-03-06 2010-09-10 日本電気株式会社 Polysiloxane-modified polylactic acid composition, composition utilizing same, molded article, and production method
JP2010280780A (en) * 2009-06-03 2010-12-16 C I Kasei Co Ltd Method for manufacturing expansion-molded body of inorganic substance-polymer composite
JP2014105275A (en) * 2012-11-27 2014-06-09 Teijin Ltd Thermoplastic resin composition for supercritical foam molding with excellent mold corrosivity
WO2018092847A1 (en) 2016-11-18 2018-05-24 住友化学株式会社 Foam-molding resin composition, method for producing foam-molded body, and foam-molded body
CN111154174A (en) * 2019-08-01 2020-05-15 华东理工大学 Additive modified polypropylene foam material and preparation method thereof
WO2021017580A1 (en) * 2019-08-01 2021-02-04 华东理工大学 Lightweight polystyrene foamed material having small pore diameter and preparation method therefor
WO2021017579A1 (en) * 2019-08-01 2021-02-04 华东理工大学 Additive modified polypropylene foam material and preparation method therefor
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