JP2010248337A - Method for producing foam - Google Patents
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Abstract
Description
本発明は、超臨界流体を用いた発泡体の製造方法に関する。 The present invention relates to a method for producing a foam using a supercritical fluid.
二酸化炭素や窒素等の物質を臨界点以上の温度及び圧力にすると超臨界流体となる。超臨界流体は、液体と気体の性質を併せ持つ流体であり、液体のように物を溶かす性質と気体のような高い拡散性を併せ持つことが知られている。超臨界流体の具体的な応用例としては、コーヒー豆からのカフェイン抽出、半導体製造工程での洗浄、クリーニング溶媒、樹脂発泡等が挙げられる。
超臨界流体を樹脂中に拡散浸透させた後、常圧まで減圧させると樹脂中の超臨界流体が気化膨張することにより発泡体が得られることが知られている。この方法により得られた発泡体は、従来の化学発泡及び物理発泡により得られた発泡体に比べて気泡サイズを小さくすることが可能となり、発泡体形成時の強度低下の少ないことが期待される。また、超臨界流体として二酸化炭素や窒素用いることによって、環境と人体により安全な成形品が可能となる。
When a substance such as carbon dioxide or nitrogen is brought to a temperature and pressure above the critical point, it becomes a supercritical fluid. A supercritical fluid is a fluid having both liquid and gas properties, and is known to have both a property of dissolving an object like a liquid and a high diffusibility like a gas. Specific application examples of the supercritical fluid include caffeine extraction from coffee beans, cleaning in a semiconductor manufacturing process, cleaning solvent, resin foaming, and the like.
It is known that when a supercritical fluid is diffused and permeated into a resin and then reduced to normal pressure, the supercritical fluid in the resin is vaporized and expanded to obtain a foam. The foam obtained by this method is capable of reducing the cell size as compared with the foam obtained by conventional chemical foaming and physical foaming, and it is expected that the strength is not lowered when the foam is formed. . Further, by using carbon dioxide or nitrogen as a supercritical fluid, a molded product that is safer for the environment and the human body becomes possible.
超臨界流体を用いた発泡体の製造方法として、例えば、特許文献１には、圧力室内に熱可塑性ポリマーを収容し、圧力室内を所定圧力、所定温度及び所定時間の条件下で超臨界流体により飽和させた後に、急速に圧力室内の圧力を減少させることにより、熱可塑性ポリマーの発泡体を製造する方法が記載されている。また、特許文献２には、圧力室内の熱可塑性ポリマーに超臨界流体を含浸させ、所定温度の条件下、所定の減圧スピードで急速に圧力室内を減圧させることにより、熱可塑性ポリマーの発泡体を製造する方法が記載されている。 As a method for producing a foam using a supercritical fluid, for example, in Patent Document 1, a thermoplastic polymer is accommodated in a pressure chamber, and the pressure chamber is subjected to a supercritical fluid under conditions of a predetermined pressure, a predetermined temperature, and a predetermined time. A method is described for producing a foam of thermoplastic polymer by rapidly reducing the pressure in the pressure chamber after saturation. Patent Document 2 discloses that a thermoplastic polymer foam is obtained by impregnating a thermoplastic polymer in a pressure chamber with a supercritical fluid and rapidly depressurizing the pressure chamber at a predetermined pressure reduction speed under a predetermined temperature condition. A method of manufacturing is described.
しかしながら、特許文献１及び特許文献２に記載の方法では、圧力室内の圧力を急速に減少させるため、超臨界流体が気体に変わる時に断熱膨張し圧力室内の温度が低下する。このような圧力室内の温度の低下は、超臨界流体として二酸化炭素を用いて１００℃未満の低い温度で処理した場合に、又は圧力室の容量が大きく超臨界流体の使用量が多くなった場合に、特に顕著に現れる。圧力室内の温度が急激に低下すれば、常圧まで減圧させた時に圧力室の内部表面にドライアイスが付着した状態となり、発泡体を圧力室から素早く取り出せなくなることがある。また、このような状態では、発泡体の表面、または発泡体の内部にドライアイスが付着し、発泡体の表面に凹凸ができたり、大きな気泡が生成される場合がある。そして、得られた発泡体は気泡サイズが不均一となり好ましくない。 However, in the methods described in Patent Document 1 and Patent Document 2, since the pressure in the pressure chamber is rapidly reduced, when the supercritical fluid is changed to gas, adiabatic expansion occurs and the temperature in the pressure chamber decreases. Such a decrease in pressure chamber temperature occurs when carbon dioxide is used as the supercritical fluid at a low temperature of less than 100 ° C., or when the volume of the pressure chamber is large and the amount of supercritical fluid used increases. In particular. If the temperature in the pressure chamber decreases rapidly, dry ice may adhere to the inner surface of the pressure chamber when the pressure is reduced to normal pressure, and the foam may not be able to be quickly removed from the pressure chamber. Further, in such a state, dry ice may adhere to the surface of the foam or inside the foam, and the surface of the foam may be uneven or large bubbles may be generated. The obtained foam is not preferable because the cell size is not uniform.
ドライアイスの発生を抑えるために、処理温度を高くすることが考えられるが、この場合、減圧後のドライアイス発生を抑えることは可能かもしれないが、得られた発泡体の気泡サイズが大きくなったり、減圧時の樹脂粘度が低くなり未発泡部分が発生する不完全な発泡体となり好ましくない。 In order to suppress the generation of dry ice, it is conceivable to increase the treatment temperature. In this case, it may be possible to suppress the generation of dry ice after decompression, but the bubble size of the obtained foam becomes large. Or an incomplete foam in which the resin viscosity at the time of decompression becomes low and an unfoamed portion is generated, which is not preferable.
圧力室内の温度低下を小さくし、ドライアイスの発生を抑えるために、減圧スピードを低速にすることが考えられるが、この場合、特許文献２の比較例に見られるように、発泡体の気泡サイズが大きくなるので好ましくない。また、気泡サイズが大きくなると薄肉の発泡体は得られなくなる。 In order to reduce the temperature drop in the pressure chamber and suppress the generation of dry ice, it is conceivable to reduce the pressure reduction speed. In this case, as seen in the comparative example of Patent Document 2, the bubble size of the foam Is unfavorable because of the increase. Further, when the bubble size is increased, a thin foam cannot be obtained.
従って、本発明の課題は、気泡サイズが細かく均一な発泡体の製造方法を提供するものである。 Accordingly, an object of the present invention is to provide a method for producing a foam having a fine and uniform cell size.
本発明は、成形用樹脂を収容する圧力室内において、成形用樹脂を超臨界流体に接触させる工程と、その後に圧力室内を減圧させる工程とを備える成形用樹脂の発泡体を得る製造方法であって、圧力室内を減圧させる工程が、第１減圧工程及び第１減圧工程より後の第２減圧工程を有し、第２減圧工程の減圧スピードが、第１減圧工程の減圧スピードよりも遅い発泡体の製造方法を提供するものである。 The present invention is a manufacturing method for obtaining a molding resin foam comprising a step of bringing a molding resin into contact with a supercritical fluid in a pressure chamber containing the molding resin, and a step of subsequently depressurizing the pressure chamber. The step of reducing the pressure in the pressure chamber has a first pressure reduction step and a second pressure reduction step after the first pressure reduction step, and the pressure reduction speed of the second pressure reduction step is lower than the pressure reduction speed of the first pressure reduction step. A method for producing a body is provided.
本発明の製造方法によれば、気泡サイズが細かく均一な発泡体を製造することができる。 According to the production method of the present invention, a foam having a fine and uniform cell size can be produced.
本発明の製造方法は、成形用樹脂を圧力室内に収容した後に、成形用樹脂を超臨界流体に接触させる工程と、その後に圧力室内を減圧させる工程とを備える。成形用樹脂を超臨界流体に接触させるまでの工程は以下のとおりである。固形の成形用樹脂を圧力室内にセットした後に、超臨界流体用原料をコンプレッサーやプランジャーポンプ等の加圧器を用いて圧力室内に供給し、圧力室内の超臨界流体用原料の圧力を臨界圧力以上にするとともに、圧力室内の温度が臨界温度以上となるように電気ヒーターやオイルヒーター等により加熱し、超臨界流体用原料を超臨界流体の状態とする。そして、成形用樹脂を超臨界流体に接触させる。その後の圧力室内を減圧させる工程は、圧力室内の圧力を減圧バルブの操作により減圧させる第１減圧工程と、それより後の第２減圧工程とをへて、最終的には常圧まで減圧させることにより成形用樹脂を発泡させる。
以下、本発明を、その好ましい実施形態に基づき説明する。発泡体の製造に用いられる装置は、減圧バルブを備えた圧力室と、圧力室に超臨界流体用原料又はこの超臨界流体用原料の超臨界流体を供給する超臨界流体供給部とを備えている。このような装置を用いた発泡体の製造方法について説明する。
The manufacturing method of the present invention includes a step of bringing a molding resin into contact with a supercritical fluid after housing the molding resin in a pressure chamber, and a step of depressurizing the pressure chamber thereafter. The process until the molding resin is brought into contact with the supercritical fluid is as follows. After the solid molding resin is set in the pressure chamber, the supercritical fluid material is supplied into the pressure chamber using a pressurizer such as a compressor or plunger pump, and the pressure of the supercritical fluid material in the pressure chamber is set to the critical pressure. In addition to the above, the temperature in the pressure chamber is heated by an electric heater, an oil heater, or the like so that the temperature becomes equal to or higher than the critical temperature, and the raw material for the supercritical fluid is brought into a supercritical fluid state. Then, the molding resin is brought into contact with the supercritical fluid. In the subsequent step of depressurizing the pressure chamber, the first depressurization step of depressurizing the pressure in the pressure chamber by operating the depressurization valve and the second depressurization step thereafter are finally depressurized to normal pressure. This causes the molding resin to foam.
Hereinafter, the present invention will be described based on preferred embodiments thereof. An apparatus used for manufacturing a foam includes a pressure chamber provided with a pressure reducing valve, and a supercritical fluid supply unit that supplies the supercritical fluid material or the supercritical fluid of the supercritical fluid material to the pressure chamber. Yes. A method for producing a foam using such an apparatus will be described.
成形用樹脂としては、ポリエチレン、エチレン酢酸ビニル共重合体（ＥＶＡ）、ポリプロピレン等のオレフィン樹脂、ポリメタクリル酸メチル、アクリル酸エチル、ポリメタクリル酸等のポリアクリル酸又はポリメタクリル酸系樹脂、ポリスチレン、ポリエステル、ポリウレタン、ナイロン、ポリオレフィンエラストマー、ポリウレタンエラストマー、ナイロンエラストマー、ポリエステルエラストマー等の熱可塑性樹脂等が挙げられる。また、メラミン樹脂、不飽和ポリエステル樹脂、熱硬化性シリコーン樹脂、熱硬化性ウレタン樹脂等の熱硬化性樹脂も用いることができる。 Examples of molding resins include polyethylene, ethylene vinyl acetate copolymer (EVA), olefin resins such as polypropylene, polyacrylic acid such as polymethyl methacrylate, ethyl acrylate, and polymethacrylic acid, or polymethacrylic acid resins, polystyrene, Examples thereof include thermoplastic resins such as polyester, polyurethane, nylon, polyolefin elastomer, polyurethane elastomer, nylon elastomer, and polyester elastomer. Moreover, thermosetting resins, such as a melamine resin, unsaturated polyester resin, a thermosetting silicone resin, and a thermosetting urethane resin, can also be used.
成形用樹脂は、ペレット、シート、又はその他の所定形状に加工された固形状のものを用いる。加工された成形用樹脂は、圧力室内に、直接にセットされる。または、加工された成形用樹脂は、予め金型等の金属製容器に収容され、その金属製容器を、圧力室内にセットする。 As the molding resin, pellets, sheets, or other solid materials processed into a predetermined shape are used. The processed molding resin is set directly in the pressure chamber. Alternatively, the processed molding resin is stored in advance in a metal container such as a mold, and the metal container is set in a pressure chamber.
ペレット、シート、又はその他の所定形状に加工した成形用樹脂を圧力室内に、直接にセットする。または、加工された成形用樹脂を、予め金属製容器に収容し、その金属製容器を、圧力室内にセットする。 The molding resin processed into pellets, sheets, or other predetermined shapes is directly set in the pressure chamber. Alternatively, the processed molding resin is previously stored in a metal container, and the metal container is set in the pressure chamber.
圧力室は、好ましくは０．５リットル〜１００リットルの内容積のものであり、更に好ましくは１リットル〜３０リットルの内容積のものを用いる。 The pressure chamber preferably has an internal volume of 0.5 to 100 liters, more preferably an internal volume of 1 to 30 liters.
成形用樹脂を直接セット、又は成形用樹脂を収容した金属製容器をセットした圧力室を、圧力室の外周に設けられたヒーター等によって加熱しながら、圧力室の内部に、超臨界流体用原料又はその超臨界流体を流体供給部から供給する。以下、供給する超臨界流体原料について詳述する。 The supercritical fluid raw material is placed inside the pressure chamber while heating the pressure chamber in which the molding resin is directly set or a metal container containing the molding resin is set by a heater provided on the outer periphery of the pressure chamber. Alternatively, the supercritical fluid is supplied from the fluid supply unit. Hereinafter, the supercritical fluid raw material to be supplied will be described in detail.
超臨界流体用原料としては、例えば窒素、酸素、二酸化炭素、アンモニア、空気、ネオン、アルゴン、エタン、プロパン、ブタン、エチレンなどの常温（２０℃）常圧で気体の原料、エタノールや水等の常温で液体の原料が挙げられる。これらの中で、成形用樹脂への溶解性に優れ、臨界温度Ｔｃ（Ｔｃ＝３１．１℃）及び臨界圧力Ｐｃ（Ｐｃ＝７．４３ＭＰａ）が常温常圧に近く、加圧工程が簡単であり、超臨界流体を得ることが容易であるため、二酸化炭素を用いることが好ましい。また樹脂の分解が無く、不燃性であり、樹脂中に残存した場合でも人体に対して安全であるという観点からも二酸化炭素が好ましい。 Examples of raw materials for supercritical fluid include nitrogen, oxygen, carbon dioxide, ammonia, air, neon, argon, ethane, propane, butane, ethylene and other gaseous materials, ethanol, water, etc. Examples include raw materials that are liquid at room temperature. Among these, the solubility in the molding resin is excellent, the critical temperature Tc (Tc = 31.1 ° C.) and the critical pressure Pc (Pc = 7.43 MPa) are close to normal temperature and normal pressure, and the pressing process is simple. Since it is easy to obtain a supercritical fluid, it is preferable to use carbon dioxide. Also, carbon dioxide is preferable from the viewpoint that there is no decomposition of the resin, it is nonflammable, and even if it remains in the resin, it is safe for the human body.
二酸化炭素や窒素のように常温（２０℃）常圧で気体の超臨界流体用原料はボンベに収容されており、ボンベの供給バルブを開いて、加圧器に供給される。二酸化炭素のように臨界温度が常温付近の超臨界流体用原料の場合、冷却器に通して液化した二酸化炭素を加圧器に供給することが好ましい。この場合の加圧器としては、プランジャーポンプが好ましい。窒素のように臨界温度が低い超臨界流体用原料の場合、冷却器を通さずに加圧器に供給することが好ましい。この場合の加圧器としてはコンプレッサーが好ましい。水やエタノールのように常温（２０℃）常圧で液体の超臨界流体用原料はタンクに収容されており、タンクの供給バルブを開いて、加圧器に供給される。この場合の加圧器としては、プランジャーポンプが好ましい。加圧器で加圧されながら超臨界流体用原料は、圧力室に供給される。 A raw material for supercritical fluid that is gaseous at normal temperature (20 ° C.) and normal pressure, such as carbon dioxide and nitrogen, is contained in a cylinder, and is supplied to a pressurizer by opening a supply valve of the cylinder. In the case of a supercritical fluid raw material having a critical temperature near room temperature, such as carbon dioxide, it is preferable to supply carbon dioxide liquefied through a cooler to the pressurizer. As the pressurizer in this case, a plunger pump is preferable. In the case of a raw material for a supercritical fluid having a low critical temperature such as nitrogen, it is preferable to supply it to the pressurizer without passing through the cooler. In this case, the pressurizer is preferably a compressor. A raw material for supercritical fluid that is liquid at normal temperature (20 ° C.) and normal pressure, such as water or ethanol, is stored in a tank, and is supplied to a pressurizer by opening a supply valve of the tank. As the pressurizer in this case, a plunger pump is preferable. While being pressurized by the pressurizer, the supercritical fluid raw material is supplied to the pressure chamber.
超臨界流体用原料を冷却器によって冷却する場合の設定温度としては、超臨界流体用原料が液化する臨界温度以下にすることが好ましい。加熱器を用いる場合の設定温度としては、成形用樹脂に超臨界流体を拡散浸透する際の圧力室内と同じ温度にすることが好ましい。 The set temperature when the supercritical fluid raw material is cooled by a cooler is preferably set to a critical temperature or lower at which the supercritical fluid raw material is liquefied. The set temperature when using a heater is preferably set to the same temperature as the pressure chamber when the supercritical fluid is diffused and penetrated into the molding resin.
成形用樹脂及び超臨界流体用原料が供給された圧力室の内部を、ヒーター等によって加熱しながら、加圧器によって超臨界流体用原料を圧力室内に供給し続けることによって圧力室内の圧力を上げ、圧力室の内部を超臨界流体の臨界温度Ｔｃ以上とし、さらに超臨界流体の臨界圧力Ｐｃ以上とする。 While heating the interior of the pressure chamber supplied with the molding resin and the raw material for the supercritical fluid with a heater or the like, the pressure in the pressure chamber is raised by continuing to supply the raw material for the supercritical fluid into the pressure chamber with the pressurizer. The inside of the pressure chamber is set to be equal to or higher than the critical temperature Tc of the supercritical fluid, and further set to be equal to or higher than the critical pressure Pc of the supercritical fluid.
圧力室の内部温度としては、超臨界流体の臨界温度Ｔｃ以上であって、さらに、上記成形用樹脂の中で、ポリエチレン、ポリプロピレン、ポリエステル、ナイロン、等の結晶性樹脂を使用する場合には、その樹脂の融点付近の温度が好ましく、ポリスチレン、ポリメタクリル酸メチル、アクリル酸エチル、ポリメタクリル酸等の非結晶性樹脂を使用する場合には、その樹脂のガラス転移温度以上の温度が好ましい。また、ＥＶＡのように結晶性樹脂の部分（ポリエチレンの部分）と非結晶性樹脂の部分（ポリ酢酸ビニルの部分）とを持つ共重合体を使用する場合には、非結晶性樹脂のガラス転移温度から結晶性樹脂の融点付近までの温度範囲が好ましい。このように内部温度を設定することにより、未発泡の樹脂部分が発生し難く、発泡体が硬くなり難い。 The internal temperature of the pressure chamber is not less than the critical temperature Tc of the supercritical fluid, and in the case of using a crystalline resin such as polyethylene, polypropylene, polyester, nylon, etc. in the molding resin, A temperature near the melting point of the resin is preferable. When an amorphous resin such as polystyrene, polymethyl methacrylate, ethyl acrylate, or polymethacrylic acid is used, a temperature equal to or higher than the glass transition temperature of the resin is preferable. When a copolymer having a crystalline resin part (polyethylene part) and an amorphous resin part (polyvinyl acetate part) is used, such as EVA, the glass transition of the amorphous resin is used. A temperature range from the temperature to the vicinity of the melting point of the crystalline resin is preferable. By setting the internal temperature in this way, an unfoamed resin portion is hardly generated and the foam is hard to be hardened.
圧力室の内部圧力（超臨界流体に接触する際の圧力）としては、超臨界流体の臨界圧力Ｐｃ以上であって、さらに、気泡サイズの適正化の観点から、臨界圧力より８ＭＰａ以上が好ましく、臨界圧力より１３ＭＰａ以上がさらに好ましい。内部圧力の上限は、製造設備の容易さの観点から、５０ＭＰａ以下であることが好ましい。 The internal pressure of the pressure chamber (pressure when contacting the supercritical fluid) is not less than the critical pressure Pc of the supercritical fluid, and more preferably 8 MPa or more than the critical pressure from the viewpoint of optimization of the bubble size, 13 MPa or more is more preferable than the critical pressure. The upper limit of the internal pressure is preferably 50 MPa or less from the viewpoint of ease of production equipment.
圧力室内の圧力が臨界圧力Ｐｃを超えて十分に上昇したら、超臨界流体供給部の供給バルブを閉めて、加圧器からの超臨界流体用原料又はその超臨界流体の供給を停止し、圧力室内を一定の圧力と温度に保つことにより、成形用樹脂を超臨界流体に接触させて、超臨界流体が成形用樹脂に拡散浸透（含浸）していく。 When the pressure in the pressure chamber sufficiently rises above the critical pressure Pc, the supply valve of the supercritical fluid supply unit is closed to stop the supply of the supercritical fluid raw material or the supercritical fluid from the pressurizer, and the pressure chamber By keeping the pressure at a constant pressure and temperature, the molding resin is brought into contact with the supercritical fluid, and the supercritical fluid diffuses and penetrates (impregnates) the molding resin.
成形用樹脂を超臨界流体に接触させる時間としては、発泡に必要な量の超臨界流体が成形用樹脂に溶解し十分に含浸する時間であれば良く、０．５時間（ｈｒ）〜３時間（ｈｒ）であることが好ましい。超臨界流体用原料として二酸化炭素を用いた場合には、液体に近い密度を持ち、また気体のように大きな拡散度及び低い粘度を示す。このような性質によって、圧力室内においては、超臨界流体が成形用樹脂に拡散浸透し、成形用樹脂内部に均一に分散する。 The time for bringing the molding resin into contact with the supercritical fluid may be any time as long as the amount of supercritical fluid necessary for foaming dissolves and sufficiently impregnates in the molding resin, and is 0.5 hours (hr) to 3 hours. (Hr) is preferred. When carbon dioxide is used as a raw material for a supercritical fluid, it has a density close to that of a liquid, and exhibits a large diffusivity and low viscosity like a gas. Due to such properties, in the pressure chamber, the supercritical fluid diffuses and penetrates into the molding resin and is uniformly dispersed inside the molding resin.
超臨界流体を十分に樹脂に拡散浸透させた後、圧力室に設けられた減圧バルブを開いて減圧する。本発明の発泡体を得る製造方法は、第１減圧工程と、この第１減圧工程の後に減圧する第２減圧工程とを有しており、第２減圧工程の減圧スピードは、第１減圧工程の減圧スピードよりも遅くする。 After the supercritical fluid is sufficiently diffused and penetrated into the resin, the pressure is reduced by opening a pressure reducing valve provided in the pressure chamber. The production method for obtaining the foam of the present invention has a first pressure reduction step and a second pressure reduction step of reducing the pressure after the first pressure reduction step, and the pressure reduction speed of the second pressure reduction step is the first pressure reduction step. Slower than the decompression speed.
先ず、第１減圧工程について詳述する。
第１減圧工程の減圧スピードは、５０〜１０００ＭＰａ／分であることが好ましく、１００〜７００ＭＰａ／分であることがさらに好ましい。減圧スピードが５０ＭＰａ／分より速ければ、発泡体の気泡サイズが小さく、セル密度が大きくなるので好ましく、減圧スピードが１０００ＭＰａ／分より遅ければ、他の吸引装置が必要とならず、圧力室の減圧バルブを開放するだけで対応できるので、設備費が低く抑えられるので好ましい。
First, the first decompression step will be described in detail.
The decompression speed of the first decompression step is preferably 50 to 1000 MPa / min, and more preferably 100 to 700 MPa / min. If the decompression speed is faster than 50 MPa / min, the bubble size of the foam is small and the cell density is preferably increased. If the decompression speed is slower than 1000 MPa / min, no other suction device is required, and the pressure chamber is decompressed. Since it can respond only by opening the valve, the equipment cost can be kept low, which is preferable.
第１減圧工程は、超臨界流体の臨界点以上の圧力及び温度の領域にあることが好ましい。即ち、第１減圧工程は、セル密度を大きくする観点から、第１減圧工程の終了時も、圧力室内の圧力が超臨界流体の臨界圧力Ｐｃ以上であって、圧力室内の温度が超臨界流体の臨界温度Ｔｃ以上であることが好ましい。 The first decompression step is preferably in the region of pressure and temperature above the critical point of the supercritical fluid. That is, from the viewpoint of increasing the cell density, the first depressurization step is such that, even at the end of the first depressurization step, the pressure in the pressure chamber is equal to or higher than the critical pressure Pc of the supercritical fluid, and the temperature in the pressure chamber is the supercritical fluid. It is preferable that it is more than the critical temperature Tc.
第１減圧工程の終了時の圧力室の内部の圧力は、発泡体内部に大きな気泡のかたまりの発生を抑制し、セル密度を高くする観点から、臨界圧力Ｐｃより１２ＭＰａ〜３ＭＰａ高い圧力であることが好ましく、臨界圧力Ｐｃより１１ＭＰａ〜４ＭＰａ高い圧力であることがさらに好ましい。また、発泡体のセル密度を高くする観点から第１減圧工程は、圧力室内部の圧力を当初の圧力から５〜１５ＭＰa減圧することが好ましい。 The pressure inside the pressure chamber at the end of the first decompression step is a pressure 12 MPa to 3 MPa higher than the critical pressure Pc from the viewpoint of suppressing the generation of large bubbles in the foam and increasing the cell density. The pressure is preferably 11 MPa to 4 MPa higher than the critical pressure Pc. Further, from the viewpoint of increasing the cell density of the foam, it is preferable that the first decompression step reduces the pressure in the pressure chamber by 5 to 15 MPa from the initial pressure.
第１減圧工程による圧力室の減圧後、第２減圧工程により圧力室内部の圧力をさらに減圧する。第１減圧工程の終了時から、第２減圧工程の開始時までの時間（減圧工程の中断時間）は、大きな気泡たまりを抑制する観点から中断時間がないか、又は中断時間が０秒（ｓｅｃ）より長く２秒（ｓｅｃ）以下であることが好ましい。 After the pressure chamber is depressurized in the first depressurization step, the pressure in the pressure chamber is further depressurized in the second depressurization step. The time from the end of the first decompression step to the start of the second decompression step (interruption time of the decompression step) is no suspension time from the viewpoint of suppressing large bubble accumulation, or the suspension time is 0 second (sec. ) Longer than 2 seconds (sec).
次に、第２減圧工程について詳述する。
第２減圧工程の減圧スピードは、０．１〜１０ＭＰａ／分であることが好ましく、３〜７ＭＰａ／分であることがさらに好ましい。減圧スピードが０．１ＭＰａ／分より速ければ、生産性が低下することがなく、１０ＭＰａ／分より遅ければ、圧力室の内部表面にドライアイスが発生し難いので好ましい。
Next, the second decompression step will be described in detail.
The decompression speed of the second decompression step is preferably 0.1 to 10 MPa / min, more preferably 3 to 7 MPa / min. If the pressure reduction speed is faster than 0.1 MPa / min, productivity is not lowered, and if it is slower than 10 MPa / min, it is preferable because dry ice hardly occurs on the inner surface of the pressure chamber.
第２減圧工程は、臨界圧力Ｐｃより１２ＭＰａ〜３ＭＰａ高い圧力から臨界圧力Ｐｃより低い圧力まで減圧することが好ましい。即ち、第２減圧工程の終了時の圧力室内の圧力は、超臨界流体の臨界圧力Ｐｃより低いことが好ましい。気泡成長は臨界圧力Ｐｃより低い圧力において行われるため、気泡成長における減圧速度を遅くすることによって気泡サイズが小さくなりすぎることを防止し、適度な大きさの柔らかな発泡体となる観点から、第２減圧工程の終了時に、圧力室内の圧力が、臨界圧力Ｐｃより低いことが好ましい。 In the second depressurization step, it is preferable to depressurize from a pressure 12 MPa to 3 MPa higher than the critical pressure Pc to a pressure lower than the critical pressure Pc. That is, the pressure in the pressure chamber at the end of the second decompression step is preferably lower than the critical pressure Pc of the supercritical fluid. Since bubble growth is performed at a pressure lower than the critical pressure Pc, it is possible to prevent the bubble size from becoming too small by slowing down the pressure reduction rate in bubble growth, and from the viewpoint of becoming a soft foam having an appropriate size. 2 At the end of the decompression step, the pressure in the pressure chamber is preferably lower than the critical pressure Pc.
第２減圧工程終了時の圧力室の内部の温度は、超臨界流体の臨界温度Ｔｃ以上であることが好ましく、さらに、気泡成長を促進するという観点から、超臨界流体を成形用樹脂に含浸させる温度より３０℃以内の範囲で低いことが好ましい。 The temperature inside the pressure chamber at the end of the second decompression step is preferably equal to or higher than the critical temperature Tc of the supercritical fluid. Further, from the viewpoint of promoting bubble growth, the supercritical fluid is impregnated into the molding resin. The temperature is preferably lower than the temperature within 30 ° C.
第２減圧工程による減圧後に、圧力室内の圧力を常圧とした後、圧力室から発泡体を取り出す。また、金属製容器を用いた場合には、圧力室から金属製容器を取り出し、さらに金属製容器内から発泡体を取り出す。本発明によれば、圧力室の内部表面にドライアイスが発生し難く、発泡体を金属製容器から取り出し易い。また、本発明によれば、金属製容器を用いた場合、圧力室の内部表面にドライアイスが発生し難く、金属製容器の外表面及び内表面（発泡体の表面）及び発泡体の内部にも、ドライアイスが発生し難いため、金属製容器から発泡体を取り出し易いだけでなく、発泡体の表面にドライアイスによる凹凸が形成されることを防止し、気泡サイズが細かく均一な超臨界発泡体を得ることができる。 After the pressure reduction in the second pressure reduction step, the pressure in the pressure chamber is set to normal pressure, and then the foam is taken out from the pressure chamber. When a metal container is used, the metal container is taken out from the pressure chamber, and the foam is taken out from the metal container. According to the present invention, dry ice hardly occurs on the inner surface of the pressure chamber, and the foam can be easily taken out from the metal container. Further, according to the present invention, when a metal container is used, dry ice hardly occurs on the inner surface of the pressure chamber, and the outer surface and inner surface of the metal container (the surface of the foam) and the inside of the foam However, since dry ice is unlikely to occur, not only is it easy to take out the foam from the metal container, but also the formation of irregularities due to dry ice on the surface of the foam is prevented, and the bubble size is fine and uniform. You can get a body.
次に、本発明を、超臨界流体用原料として最も好ましい二酸化炭素を用いた場合の好ましい実施形態に基づき図面を参照しながら説明する。図１は、発泡体の製造に用いられている装置の一例の概略図を示す。装置は、減圧バルブを備えた圧力室１と、圧力室１に超臨界流体用原料である二酸化炭素を供給する、又はこの二酸化炭素の超臨界流体である超臨界二酸化炭素を供給する超臨界流体供給部２とを備えている。以下、図１に示す装置を用いた発泡体の製造方法について具体的に説明する。 Next, the present invention will be described with reference to the drawings based on a preferred embodiment in the case of using carbon dioxide that is most preferable as a supercritical fluid raw material. FIG. 1 shows a schematic view of an example of an apparatus used for the production of foam. The apparatus includes a pressure chamber 1 having a pressure reducing valve, and a supercritical fluid that supplies carbon dioxide that is a raw material for the supercritical fluid to the pressure chamber 1 or supplies supercritical carbon dioxide that is a supercritical fluid of the carbon dioxide. And a supply unit 2. Hereinafter, a method for producing a foam using the apparatus shown in FIG. 1 will be specifically described.
成形用樹脂としては、上述した樹脂を用いることができる。ペレット、シート、又はその他の所定形状に加工した成形用樹脂を図１に示す圧力室１内に、直接セットする。または、加工された成形用樹脂を、予め図３に示す金属製容器３に収容し、その金属製容器３を、圧力室１内にセットする。 The resin described above can be used as the molding resin. A molding resin processed into pellets, sheets, or other predetermined shapes is directly set in the pressure chamber 1 shown in FIG. Alternatively, the processed molding resin is stored in advance in a metal container 3 shown in FIG. 3, and the metal container 3 is set in the pressure chamber 1.
成形用樹脂を収容する金属製容器３は、図３に示すように、矩形状の２枚の金属板３１，３２からなり、金属板３２における金属板３１との対向面には、成形用樹脂を収容する凹部３３が形成されている。また、金属板３２には、凹部３３に接続されたガス抜き溝３４が形成されている。凹部３３の形状は、図２（ａ）に示すような歯間ブラシのブラシ部４若しくは図２（ｂ）に示すような舌ブラシのブラシ部５等の製品の形状に応じて形成される。凹部３３に成形用樹脂を収容した後、金属板３１及び金属板３２の四隅をボルトとナットによりボルト締めすることにより一体化する。この金属製容器３を、圧力室１の内部にセットする。 As shown in FIG. 3, the metal container 3 that accommodates the molding resin is composed of two rectangular metal plates 31 and 32, and the molding resin is disposed on the surface of the metal plate 32 facing the metal plate 31. The recessed part 33 which accommodates is formed. The metal plate 32 is formed with a gas vent groove 34 connected to the recess 33. The shape of the recess 33 is formed according to the shape of the product such as the brush part 4 of the interdental brush as shown in FIG. 2A or the brush part 5 of the tongue brush as shown in FIG. After the molding resin is accommodated in the recess 33, the four corners of the metal plate 31 and the metal plate 32 are integrated by bolting with bolts and nuts. The metal container 3 is set inside the pressure chamber 1.
成形用樹脂を直接セット、又は成形用樹脂を収容した金属製容器３をセットした圧力室１を、図１に示すように、圧力室１の外周に設けられたヒーター１１によって加熱しながら、圧力室１の内部に、二酸化炭素又は超臨界二酸化炭素を流体供給部２から供給する。 While the pressure chamber 1 in which the molding resin is directly set or the metal container 3 containing the molding resin is set is heated by the heater 11 provided on the outer periphery of the pressure chamber 1 as shown in FIG. Carbon dioxide or supercritical carbon dioxide is supplied into the chamber 1 from the fluid supply unit 2.
超臨界流体用原料である二酸化炭素は、図１に示すように、ボンベ２１に収容されており、ボンベ２１の供給バルブを開いて、冷却器２２に供給される。冷却器２２により冷却され液化した二酸化炭素を、図１に示すように、プランジャーポンプ２３を用いて圧力室１内に供給する。液化された二酸化炭素は、圧力室１内に供給される前に、図１に示す加熱器２４により加熱されながら圧力室１内に供給される。 As shown in FIG. 1, carbon dioxide, which is a raw material for the supercritical fluid, is accommodated in the cylinder 21, and is supplied to the cooler 22 by opening the supply valve of the cylinder 21. The carbon dioxide cooled and liquefied by the cooler 22 is supplied into the pressure chamber 1 using a plunger pump 23 as shown in FIG. The liquefied carbon dioxide is supplied into the pressure chamber 1 while being heated by the heater 24 shown in FIG. 1 before being supplied into the pressure chamber 1.
超臨界流体用原料として二酸化炭素を用いた場合の冷却器２２の冷却温度としては、−１０℃〜３０℃であることが好ましく、−５℃〜５℃であることが更に好ましい。 The cooling temperature of the cooler 22 when carbon dioxide is used as the raw material for the supercritical fluid is preferably −10 ° C. to 30 ° C., and more preferably −5 ° C. to 5 ° C.
二酸化炭素を冷却器２２によって冷却する場合は、プランジャーポンプ２３と圧力室１との間に加熱器２４を設けることが好ましい。超臨界流体用原料として二酸化炭素を用いた場合の加熱器２４の加熱温度としては、臨界温度以上であることが好ましく、成形用樹脂が結晶性の場合には、融点近傍がさらに好ましく（例えば融点±２０℃、好ましくは±１０℃）、非晶性の場合には、ガラス転移温度以上であることがさらに好ましい。 When carbon dioxide is cooled by the cooler 22, it is preferable to provide a heater 24 between the plunger pump 23 and the pressure chamber 1. The heating temperature of the heater 24 when carbon dioxide is used as the raw material for the supercritical fluid is preferably equal to or higher than the critical temperature, and more preferably near the melting point when the molding resin is crystalline (for example, the melting point) ± 20 ° C., preferably ± 10 ° C.) In the case of amorphous, it is more preferable that the glass transition temperature or higher.
成形用樹脂及び二酸化炭素、又は成形用樹脂及び超臨界二酸化炭素が供給された圧力室１の内部を、ヒータ１１によって加熱しながら、プランジャーポンプ２３によって、二酸化炭素又は超臨界二酸化炭素を圧力室１内に供給し続け、圧力室１内の圧力を上げ、圧力室１の内部を超臨界二酸化炭素の臨界温度Ｔｃ以上とし、さらに超臨界二酸化炭素の臨界圧力Ｐｃ以上とする。 While the interior of the pressure chamber 1 supplied with the molding resin and carbon dioxide, or the molding resin and supercritical carbon dioxide is heated by the heater 11, the plunger pump 23 supplies the carbon dioxide or supercritical carbon dioxide to the pressure chamber. The pressure in the pressure chamber 1 is increased, and the pressure chamber 1 is brought to the critical temperature Tc of supercritical carbon dioxide or higher, and further to the critical pressure Pc of supercritical carbon dioxide or higher.
圧力室１の内部温度としては、超臨界二酸化炭素の臨界温度Ｔｃ以上であって、さらに、上記成形用樹脂の中で、ポリエチレン、ポリプロピレン、ポリエステル、ナイロン、等の結晶性樹脂を使用する場合には、その樹脂の融点近傍の温度が好ましく、ポリスチレン、ポリメタクリル酸メチル、アクリル酸エチル、ポリメタクリル酸等の非結晶性樹脂を使用する場合には、その樹脂のガラス転移温度以上の温度が好ましい。また、ＥＶＡのように結晶性樹脂の部分（ポリエチレンの部分）と非結晶性樹脂の部分（ポリ酢酸ビニルの部分）とを持つ共重合体を使用する場合には、非結晶性樹脂のガラス転移温度から結晶性樹脂の融点付近までの温度範囲が好ましい。このように圧力室１の内部温度を設定することにより、未発泡の樹脂部分が発生し難く、発泡体が硬くなり難い。 The internal temperature of the pressure chamber 1 is equal to or higher than the critical temperature Tc of supercritical carbon dioxide, and when a crystalline resin such as polyethylene, polypropylene, polyester, or nylon is used in the molding resin. Is preferably a temperature in the vicinity of the melting point of the resin, and when an amorphous resin such as polystyrene, polymethyl methacrylate, ethyl acrylate, polymethacrylic acid or the like is used, a temperature equal to or higher than the glass transition temperature of the resin is preferable. . When a copolymer having a crystalline resin part (polyethylene part) and an amorphous resin part (polyvinyl acetate part) is used, such as EVA, the glass transition of the amorphous resin is used. A temperature range from the temperature to the vicinity of the melting point of the crystalline resin is preferable. By setting the internal temperature of the pressure chamber 1 in this way, an unfoamed resin portion is hardly generated and the foam is hard to be hardened.
圧力室１の内部圧力としては、超臨界二酸化炭素の臨界圧力Ｐｃ以上であって、さらに、気泡サイズの適正化の観点から、１２ＭＰａより高圧が好ましく、１９ＭＰａより高圧がさらに好ましく、２０ＭＰａ以上が特に好ましい。内部圧力の上限は、設備製造の容易さの観点から、５０ＭＰａ以下であることが好ましい。 The internal pressure of the pressure chamber 1 is equal to or higher than the critical pressure Pc of supercritical carbon dioxide, and is preferably higher than 12 MPa, more preferably higher than 19 MPa, and particularly preferably higher than 20 MPa from the viewpoint of optimizing the bubble size. preferable. The upper limit of the internal pressure is preferably 50 MPa or less from the viewpoint of ease of equipment manufacture.
圧力室１内の圧力が臨界圧力Ｐｃを超えて十分に上昇したら、流体供給部２の供給バルブを閉めて、プランジャーポンプ２３からの二酸化炭素又は超臨界二酸化炭素の供給を停止し、圧力室１内を一定の圧力と温度に保つことにより、成形用樹脂を超臨界二酸化炭素に接触させて、超臨界流体が成形用樹脂に拡散浸透（含浸）していく。 When the pressure in the pressure chamber 1 sufficiently rises above the critical pressure Pc, the supply valve of the fluid supply unit 2 is closed to stop the supply of carbon dioxide or supercritical carbon dioxide from the plunger pump 23, and the pressure chamber By keeping the inside of 1 at a constant pressure and temperature, the molding resin is brought into contact with supercritical carbon dioxide, and the supercritical fluid diffuses and penetrates (impregnates) the molding resin.
超臨界二酸化炭素を含浸させる時間としては、発泡に必要な量の超臨界二酸化炭素が成形用樹脂に溶解する時間であれば良く、０．５時間（ｈｒ）〜３時間（ｈｒ）であることが好ましい。超臨界二酸化炭素は、気体のような高い拡散浸透性と低い粘度を有し、特に、液体に近い密度を持つ。このような性質によって、圧力室１内においては、超臨界二酸化炭素が成形用樹脂に拡散浸透し、成形用樹脂内部に均一に分散する。 The time for impregnating the supercritical carbon dioxide may be any time as long as the amount of supercritical carbon dioxide necessary for foaming is dissolved in the molding resin, and is 0.5 hours (hr) to 3 hours (hr). Is preferred. Supercritical carbon dioxide has high diffusion permeability like gas and low viscosity, and in particular has a density close to that of a liquid. Due to such properties, in the pressure chamber 1, supercritical carbon dioxide diffuses and penetrates into the molding resin and is uniformly dispersed inside the molding resin.
超臨界二酸化炭素を十分に樹脂に拡散浸透させた後、圧力室１に設けられた減圧バルブ１２を開いて減圧する。本発明の発泡体を得る製造方法は、第１減圧工程と、該第１減圧工程の後に減圧する第２減圧工程とを有しており、前記第２減圧工程の減圧スピードが、前記第１減圧工程の減圧スピードよりも遅いことを特徴とする。 After the supercritical carbon dioxide is sufficiently diffused and permeated into the resin, the pressure is reduced by opening the pressure reducing valve 12 provided in the pressure chamber 1. The production method for obtaining the foam of the present invention includes a first pressure reduction step and a second pressure reduction step of reducing the pressure after the first pressure reduction step, and the pressure reduction speed of the second pressure reduction step is the first pressure reduction step. It is characterized by being slower than the decompression speed of the decompression step.
先ず、第１減圧工程について詳述する。
第１減圧工程の減圧スピードは、５０〜１０００ＭＰａ／分であることが好ましく、１０００〜８００ＭＰａ／分であることがさらに好ましい。減圧スピードが５０ＭＰａ／分より速ければ、発泡体の気泡サイズが小さく、セル密度が大きくなるので好ましく、減圧スピードが１０００ＭＰａ／分より遅ければ、他の吸引装置が必要とならず、圧力室１の減圧バルブ１２を開放するだけで対応できるので、設備費が低く抑えられるので好ましい。
First, the first decompression step will be described in detail.
The decompression speed of the first decompression step is preferably 50 to 1000 MPa / min, and more preferably 1000 to 800 MPa / min. If the decompression speed is faster than 50 MPa / min, the bubble size of the foam is small and the cell density is preferably increased. If the decompression speed is slower than 1000 MPa / min, no other suction device is required, and the pressure chamber 1 Since it can respond by only opening the pressure reducing valve 12, it is preferable because the equipment cost can be kept low.
第１減圧工程は、超臨界二酸化炭素の臨界点以上の圧力及び温度の領域にあることが好ましい。即ち、第１減圧工程は、セル密度を大きくするという観点から、第１減圧工程終了時も、圧力室１内の圧力が超臨界二酸化炭素の臨界圧力Ｐｃ以上であって、圧力室１内の温度が超臨界二酸化炭素の臨界温度Ｔｃ以上であることが好ましい。 The first decompression step is preferably in the region of pressure and temperature above the critical point of supercritical carbon dioxide. That is, in the first decompression step, from the viewpoint of increasing the cell density, the pressure in the pressure chamber 1 is equal to or higher than the critical pressure Pc of supercritical carbon dioxide even at the end of the first decompression step. The temperature is preferably equal to or higher than the critical temperature Tc of supercritical carbon dioxide.
第１減圧工程終了時の圧力室１の内部の圧力は、超臨界二酸化炭素の臨界圧力Ｐｃ以上であることが好ましく、さらに、発泡体内部に大きな気泡のかたまりが発生し難く、セル密度が高くなりやすい大きくなり難いとの観点から、１９ＭＰａ〜１１ＭＰａであることが好ましく、１８ＭＰａ〜１２ＭＰａであることがさらに好ましい。また、第１減圧工程による減圧は、５〜１５ＭＰaであることが好ましい。 The pressure in the pressure chamber 1 at the end of the first decompression step is preferably equal to or higher than the critical pressure Pc of supercritical carbon dioxide, and further, a large cell mass is hardly generated inside the foam, and the cell density is high. From the viewpoint that it is likely to become large, it is preferably 19 MPa to 11 MPa, and more preferably 18 MPa to 12 MPa. Moreover, it is preferable that the pressure reduction by a 1st pressure reduction process is 5-15 MPa.
第１減圧工程による圧力室１の減圧後、第２減圧工程により圧力室１の内部の圧力をさらに減圧する。第１減圧工程終了時から、減圧開始までの時間は、０秒（ｓｅｃ）〜２秒（ｓｅｃ）であることが好ましい。中断を２秒以内とすることにより大きな気泡たまりがなくなるので好ましい。 After the pressure chamber 1 is depressurized in the first depressurization step, the pressure in the pressure chamber 1 is further depressurized in the second depressurization step. The time from the end of the first decompression step to the start of decompression is preferably 0 second (sec) to 2 seconds (sec). It is preferable that the interruption is within 2 seconds because a large bubble pool is eliminated.
次に、第２減圧工程について詳述する。
第２減圧工程の減圧スピードは、０．１〜１０ＭＰａ／分であることが好ましく、３〜７ＭＰａ／分であることがさらに好ましい。減圧スピードが０．１ＭＰａ／分より速ければ、生産性が低下することがなく、１０ＭＰａ／分より遅ければ、圧力室１の内部表面にドライアイスが発生し難いので好ましい。
Next, the second decompression step will be described in detail.
The decompression speed of the second decompression step is preferably 0.1 to 10 MPa / min, more preferably 3 to 7 MPa / min. If the decompression speed is faster than 0.1 MPa / min, productivity is not lowered, and if it is slower than 10 MPa / min, it is preferable because dry ice hardly occurs on the inner surface of the pressure chamber 1.
第２減圧工程は、超臨界二酸化炭素の臨界圧力Ｐｃより低い圧力まで減圧することが好ましい。即ち、気泡成長は臨界圧力より低い圧力において行われる。この時の減圧速度を遅くすることにより気泡サイズが小さくなりすぎることなく柔らかな発泡体となるという観点から、第２減圧工程終了時に、圧力室１内の圧力が、臨界圧力Ｐｃより低いであることが好ましい。 In the second depressurizing step, it is preferable to depressurize to a pressure lower than the critical pressure Pc of supercritical carbon dioxide. That is, bubble growth is performed at a pressure lower than the critical pressure. The pressure in the pressure chamber 1 is lower than the critical pressure Pc at the end of the second decompression step from the viewpoint that the bubble size does not become too small by slowing down the decompression speed at this time, and the soft foam is formed. It is preferable.
第２減圧工程終了時の圧力室１の内部の圧力は、超臨界二酸化炭素の臨界圧力Ｐｃ（７．１３ＭＰａ）より低いことが好ましく、超臨界二酸化炭素では７ＭＰａ以下であることが好ましく、さらに、製造工程の簡素化の観点から、常圧であることが好ましい。圧力室１内の圧力が３ＭＰａ以下であれば第２減圧工程の後に１０ＭＰａ／分より早い速度で減圧を行っても良い。 The pressure inside the pressure chamber 1 at the end of the second decompression step is preferably lower than the critical pressure Pc (7.13 MPa) of supercritical carbon dioxide, preferably 7 MPa or less for supercritical carbon dioxide, From the viewpoint of simplification of the production process, normal pressure is preferred. If the pressure in the pressure chamber 1 is 3 MPa or less, the pressure reduction may be performed at a speed higher than 10 MPa / min after the second pressure reduction process.
第２減圧工程終了時の圧力室１の内部の温度は、超臨界二酸化炭素の臨界温度Ｔｃ（３２℃）以上であることが好ましく、さらに、気泡成長を促進するという観点から、超臨界二酸化炭素を成形用樹脂に含浸させる温度より３０℃以内の範囲で低いことであることが好ましい。 The temperature inside the pressure chamber 1 at the end of the second decompression step is preferably equal to or higher than the critical temperature Tc (32 ° C.) of supercritical carbon dioxide, and from the viewpoint of promoting bubble growth, supercritical carbon dioxide. It is preferable that the temperature be lower than the temperature at which the molding resin is impregnated within 30 ° C.
第２減圧工程による減圧後に、圧力室１内の圧力を常圧とした後、圧力室１から発泡体を取り出す。また、金属製容器３を用いた場合には、圧力室１から金属製容器３を取り出し、ボルトとナットをゆるめて、金属板３２の凹部３３から発泡体を取り出す。本発明によれば、圧力室１の内部表面にドライアイスが発生し難く、発泡体を取り出し易い。また、本発明によれば、金属製容器３を用いた場合、圧力室１の内部表面にドライアイスが発生し難く、金属製容器３の外表面及び内表面（発泡体の表面）、発泡体の内部にも、ドライアイスが発生し難いため、金属製容器３から発泡体を取り出し易い。本発明により得られる発泡体は、気泡サイズが細かく、均一な超臨界発泡体である。 After the pressure reduction in the second pressure reduction step, the pressure in the pressure chamber 1 is set to normal pressure, and then the foam is taken out from the pressure chamber 1. When the metal container 3 is used, the metal container 3 is taken out from the pressure chamber 1, the bolts and nuts are loosened, and the foam is taken out from the recess 33 of the metal plate 32. According to the present invention, dry ice hardly occurs on the inner surface of the pressure chamber 1, and the foam can be easily taken out. In addition, according to the present invention, when the metal container 3 is used, dry ice hardly occurs on the inner surface of the pressure chamber 1, and the outer surface and inner surface (the surface of the foam) of the metal container 3, the foam Since it is difficult for dry ice to be generated inside, it is easy to take out the foam from the metal container 3. The foam obtained by the present invention is a uniform supercritical foam having a fine cell size.
本発明により得られた超臨界発泡体とは、気泡サイズが細かく且つ均一な発泡セル領域と、発泡セル領域の全周面を覆うスキン層とから形成される発泡体のことをいう。発泡セルは各々のセルがセル壁で隔離された独立発泡セル及びセル壁が連通した連続発泡セルが含まれる。本発明により得られる発泡体の発泡セル領域における気泡のセル面積は、２００〜３２０００μｍ2であり、好ましくは３００〜５０００μｍ2であり、セル同士の間の間隔（セル壁の厚み）は、０．１μｍ〜５μｍであることが好ましい。ここで、スキン層とは、気泡を含まない部分及びセル面積が２００μｍ2より小さい気泡を含む部分のことをいい、その厚みは、０μｍ〜７０μｍである。尚、セル面積、セル壁の厚み、スキン層の厚みは、以下の方法により測定する。 The supercritical foam obtained by the present invention refers to a foam formed from a foam cell region having a fine and uniform cell size and a skin layer covering the entire peripheral surface of the foam cell region. The foam cell includes an independent foam cell in which each cell is isolated by a cell wall and a continuous foam cell in which the cell walls communicate with each other. Cell area of the bubbles in the foam cell area of the foam obtained by the present invention is 200～32000Myuemu 2, preferably 300～5000Myuemu 2, the distance between between cells (the thickness of the cell wall) is 0. It is preferable that it is 1 micrometer-5 micrometers. Here, the skin layer refers to a portion that does not include bubbles and a portion that includes bubbles having a cell area smaller than 200 μm 2, and has a thickness of 0 μm to 70 μm. The cell area, cell wall thickness, and skin layer thickness are measured by the following methods.
＜セル面積等の測定法＞
セル面積の測定は、走査型電子顕微鏡（リアルサーフェイス顕微鏡 商品名ＶＥ７８００；（株）キーエンス製）を用いて測定できる。得られた超臨界発泡体を、その中心を通るようにカッターで半分に切断する。走査型電子顕微鏡を用いて、超臨界発泡体の切断面の拡大写真を撮影する。そして、この拡大写真から、１０個の気泡（セル）を選択し、画像処理ソフト（商品名ウィンルーフ バージョン５．６．２ 三谷商事製）を用いて、それぞれの気泡における面積を測定する。それらの結果から各気泡の平均面積を算出し、セル面積とする。尚、セル壁の厚みは、同様に、走査型電子顕微鏡を用いて、超臨界発泡体の切断面の拡大写真を撮影し、この拡大写真から、気泡同士の間の間隔を１０箇所測定し、測定値の平均をセル壁の厚みとする。尚、気泡同士の間隔が２０μｍ以上である場合は、未発泡部分とする。スキン層の厚みも同様に走査型電子顕微鏡を用いて、超臨界発泡体の切断面の拡大写真を撮影し、この拡大写真から、スキン層の厚みを１０箇所測定し、測定値の平均をスキン層の厚みとする。
<Measurement method of cell area>
The cell area can be measured using a scanning electron microscope (real surface microscope, trade name VE7800; manufactured by Keyence Corporation). The supercritical foam obtained is cut in half with a cutter so as to pass through the center. An enlarged photograph of the cut surface of the supercritical foam is taken using a scanning electron microscope. Then, 10 bubbles (cells) are selected from this enlarged photograph, and the area of each bubble is measured using image processing software (trade name Winroof version 5.6.2, manufactured by Mitani Corp.). From these results, the average area of each bubble is calculated and used as the cell area. In addition, the thickness of the cell wall is similarly taken using a scanning electron microscope, taking an enlarged photograph of the cut surface of the supercritical foam, and from this enlarged photograph, the interval between the bubbles is measured at 10 locations, The average of the measured values is the cell wall thickness. In addition, when the space | interval of bubbles is 20 micrometers or more, it is set as an unfoamed part. Similarly, for the thickness of the skin layer, an enlarged photograph of the cut surface of the supercritical foam was taken using a scanning electron microscope, and from this enlarged photograph, the thickness of the skin layer was measured at 10 locations, and the average of the measured values was determined for the skin. Let it be the thickness of the layer.
本発明により得られる発泡体の発泡セル領域における気泡の均一性は、セル面積、セル壁の厚み及びセル密度により判断する。気泡が均一であるとは、セル面積が２００μｍ2〜３２０００μｍ2の範囲にあり、セル壁の厚みが５μｍ以下であり且つセル密度が２５００個／ｃｍ2〜２５００００個／ｃｍ2の範囲にあり発泡体切断面の気泡同士の間隔が２０μｍ以上の未発泡部分が無い均一なセルで形成されていることをいう。尚、セル密度は、以下の方法により測定する。 The uniformity of bubbles in the foamed cell region of the foam obtained by the present invention is determined by the cell area, the thickness of the cell wall, and the cell density. Bubbles is uniform, there cell area in the range of 200μm 2 ~32000μm 2, and cell density thickness of the cell walls is at 5μm or less is in the range of 2500 / cm 2 ～250000 pieces / cm 2 expanded It means that the gap between the air bubbles on the body cut surface is formed by uniform cells having no unfoamed portion of 20 μm or more. The cell density is measured by the following method.
＜セル密度の測定法＞
超臨界発泡体の切断面１ｃｍ2当たりに気泡が何個含まれているのかを表すセル密度も走査型電子顕微鏡を用いて測定する。
<Measurement method of cell density>
Cell density indicating whether Included how many bubbles on the cut surface 1 cm 2 per the supercritical foam also be measured using a scanning electron microscope.
本発明により得られる発泡体は、気泡サイズが細かいため、発泡体形成時の強度低下が発生し難いと共に衝撃吸収性等の効果が優れており、また、気泡同士の間隔が２０μｍ以上の未発泡部分のない均一な気泡であるため、滑らかで良好な感触を発現する。そして、このような発泡体を、肉厚が０.１〜３０ｍｍ、好ましくは０．５〜１０ｍｍの薄肉発泡体や、表面に突部や窪みを備える成形品であっても得ることができる。 Since the foam obtained by the present invention has a fine bubble size, it is difficult to cause a decrease in strength during foam formation and has excellent effects such as shock absorption, and an unfoamed foam having an interval between the bubbles of 20 μm or more. Because it is a uniform bubble with no part, it produces a smooth and good feel. And such a foam can be obtained even if it is a thin-walled foam having a thickness of 0.1 to 30 mm, preferably 0.5 to 10 mm, or a molded product having protrusions and depressions on the surface.
そのため、圧力室１に成形用樹脂を直接セットすることにより得られた発泡体は、図２（ａ）に示すような歯間ブラシのブラシ部４、図２（ｂ）に示すような舌ブラシのブラシ部５、メイクアップ化粧パフ、デンタルフロス等の薄肉製品として使用することができる。これら薄肉製品を得るために成形用樹脂をそれぞれの製品形状となる金型内にセットした後、圧力室１内に収容し、超臨界流体にて発泡処理を行うことが好ましい。尚、図２（ａ）に示すような歯間ブラシのブラシ部４は、その長さが、５ｍｍ〜２０ｍｍであり、その幅が０．８ｍｍ〜５ｍｍのものである。図２（ｂ）に示すような舌ブラシのブラシ部５は、その長さが、１０ｍｍ〜３０ｍｍであり、その幅が５ｍｍ〜２０ｍｍのものである。 Therefore, the foam obtained by directly setting the molding resin in the pressure chamber 1 is the brush part 4 of the interdental brush as shown in FIG. 2 (a) and the tongue brush as shown in FIG. 2 (b). Can be used as thin-walled products such as a brush part 5, makeup makeup puffs, and dental floss. In order to obtain these thin-walled products, it is preferable that the molding resin is set in the molds having the respective product shapes, then accommodated in the pressure chamber 1 and foamed with a supercritical fluid. The brush part 4 of the interdental brush as shown in FIG. 2A has a length of 5 mm to 20 mm and a width of 0.8 mm to 5 mm. The brush part 5 of the tongue brush as shown in FIG. 2B has a length of 10 mm to 30 mm and a width of 5 mm to 20 mm.
以上、本発明をその好ましい実施形態に基づき説明したが、本発明は前記実施形態に制限されない。例えば、第２減圧工程の減圧スピードが、前記第１減圧工程の減圧スピードよりも遅ければ、前述の説明に制限されない。また、第１減圧工程と第２減圧工程以外の減圧スピードからなる減圧工程を有するものであっても良い。 As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, as long as the decompression speed of the second decompression step is slower than the decompression speed of the first decompression step, the above description is not restrictive. Moreover, you may have the pressure reduction process which consists of pressure reduction speeds other than a 1st pressure reduction process and a 2nd pressure reduction process.
また、前記実施形態においては、圧力室１の内部に、成形用樹脂及び超臨界流体用原料（二酸化炭素）のみ、又は成形用樹脂及び超臨界流体（超臨界二酸化炭素）のみが供給されているが、それらに加え、成形用樹脂の可塑剤や改質剤等を圧力室１の内部に供給してもよい。 In the embodiment, only the molding resin and the raw material for supercritical fluid (carbon dioxide) or only the molding resin and the supercritical fluid (supercritical carbon dioxide) are supplied into the pressure chamber 1. However, in addition to these, a plasticizer or a modifier for the molding resin may be supplied into the pressure chamber 1.
また、超臨界流体用原料として二酸化炭素を用いた場合の前記実施形態においては、金属製容器３は、図３に示すように、金属板３２に、歯間ブラシのブラシ部４若しくは舌ブラシのブラシ部５等の製品の形状に応じて形成された凹部３３を１個有しているが、複数個の凹部３３を有していてもよい。 Moreover, in the said embodiment at the time of using a carbon dioxide as a raw material for supercritical fluids, as shown in FIG. 3, the metal container 3 is attached to the metal plate 32 on the brush part 4 of the interdental brush or the tongue brush. Although one recess 33 formed according to the shape of the product such as the brush portion 5 is provided, a plurality of recesses 33 may be provided.
以下、実施例により本発明を更に詳細に説明する。しかしながら本発明の範囲はかかる実施例に制限されない。 Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples.
〔発泡体の成形用樹脂シートの作製〕
成形用樹脂としては、東ソー株式会社製の商品名ウルトラセン７１０（エチレン酢酸ビニル共重合体：酢酸ビニル含量２６重量％）を用い、それを加熱プレスし、厚み０．６ｍｍのシートとしたものを、３０ｍｍ×３０ｍｍにカットし成形用樹脂シートを作製した。ウルトラセン７１０は、結晶性樹脂の部分と非結晶性の部分とを併せ持つ共重合体の樹脂であり、結晶性樹脂の部分の融点が７２℃であり非結晶性の部分のガラス転移温度が３１℃であった。融点及びガラス転移温度の測定には、示差走査熱量計（ＤＳＣ）（セイコーインスツルメント社製、商品名EXTＲＡ６０００）を用いた。
[Preparation of foam molding resin sheet]
As the molding resin, the product name Ultrasen 710 (ethylene vinyl acetate copolymer: vinyl acetate content 26% by weight) manufactured by Tosoh Corporation was used, and it was heated and pressed to form a sheet having a thickness of 0.6 mm. The resin sheet for shaping | molding was produced by cutting into 30 mm x 30 mm. Ultracene 710 is a copolymer resin having both a crystalline resin portion and an amorphous portion. The melting point of the crystalline resin portion is 72 ° C., and the glass transition temperature of the amorphous portion is 31. ° C. A differential scanning calorimeter (DSC) (manufactured by Seiko Instruments Inc., trade name EXTRA6000) was used for measurement of the melting point and glass transition temperature.
〔実施例１〕
発泡処理装置としては、図１に示す装置を用いた。圧力室１は内容積１リットルのものを用いた。成形用樹脂シートを収容する金属製容器３としては、図３に示すアルミ製容器を用いた。
金属板３２の凹部３３に成形用樹脂シートを収容した金属製容器３を、ヒーター１１の処理温度を７０℃に設定した圧力室１の内部にセットした。次に、ボンベ２１から超臨界二酸化炭素を冷却器２２、プランジャーポンプ２３、加熱器２４を通して密閉状態の圧力室１に供給する。冷却器２２の設定温度は、０℃とし、ガス状の二酸化炭素を一旦液化させたものをプランジャーポンプ２３で送り、設定温度７０℃で加熱された加熱器２４を通して二酸化炭素を圧力室１に供給し続け、圧力室１内の圧力が２５ＭＰａになるまで圧力を上げた。圧力室内の温度７０℃、圧力２５ＭＰａになった後、超臨界流体供給部２の供給バルブを閉めて、その温度及び圧力の状態を１時間保持し、超臨界二酸化炭素を成形用樹脂に含浸溶解させた。続いて、圧力室１の減圧バルブ１２を開いて減圧スピード６００ＭＰａ／分にて減圧し、圧力室１内の圧力を２５ＭＰａから１８ＭＰａに減圧した（第１減圧工程）。次に、再度、圧力室１の減圧バルブ１２を開いて減圧スピード４ＭＰａ／分にて減圧し、圧力室１内の圧力を１８ＭＰａから常圧まで減圧（第２減圧工程）し、成形用樹脂を発泡させた。尚、第１減圧工程の終了時と第２減圧工程の開始時との間の時間は、０．５秒であった。
[Example 1]
The apparatus shown in FIG. 1 was used as the foaming apparatus. The pressure chamber 1 has an internal volume of 1 liter. As the metal container 3 for housing the molding resin sheet, an aluminum container shown in FIG. 3 was used.
The metal container 3 containing the molding resin sheet in the recess 33 of the metal plate 32 was set inside the pressure chamber 1 where the processing temperature of the heater 11 was set to 70 ° C. Next, supercritical carbon dioxide is supplied from the cylinder 21 to the sealed pressure chamber 1 through the cooler 22, the plunger pump 23, and the heater 24. The set temperature of the cooler 22 is set to 0 ° C., gaseous carbon dioxide is once liquefied and sent by the plunger pump 23, and the carbon dioxide is supplied to the pressure chamber 1 through the heater 24 heated at the set temperature 70 ° C. The supply was continued and the pressure was increased until the pressure in the pressure chamber 1 reached 25 MPa. After the temperature in the pressure chamber reaches 70 ° C. and the pressure is 25 MPa, the supply valve of the supercritical fluid supply unit 2 is closed and the temperature and pressure are maintained for 1 hour, so that supercritical carbon dioxide is impregnated and dissolved in the molding resin. I let you. Subsequently, the pressure reducing valve 12 of the pressure chamber 1 was opened and the pressure was reduced at a pressure reducing speed of 600 MPa / min, and the pressure in the pressure chamber 1 was reduced from 25 MPa to 18 MPa (first pressure reducing step). Next, the pressure reducing valve 12 of the pressure chamber 1 is opened again and the pressure is reduced at a pressure reducing speed of 4 MPa / min. The pressure in the pressure chamber 1 is reduced from 18 MPa to normal pressure (second pressure reducing step), and the molding resin is removed. Foamed. The time between the end of the first decompression step and the start of the second decompression step was 0.5 seconds.
〔実施例２〕
実施例１において、第１減圧工程の減圧スピードを８００ＭＰａ／分とし、第１減圧工程により圧力室１内の圧力を２５ＭＰａから１２ＭＰａに減圧する以外は実施例１と同様にして成形用樹脂を発泡させた。
[Example 2]
In Example 1, the molding resin is foamed in the same manner as in Example 1 except that the decompression speed of the first decompression step is 800 MPa / min and the pressure in the pressure chamber 1 is decompressed from 25 MPa to 12 MPa by the first decompression step. I let you.
〔実施例３〕
実施例１において、プランジャーポンプ２３により圧力室１内の圧力を２０ＭＰａになるまで圧力を上げ、第１減圧工程の減圧スピードを５００ＭＰａ／分とし、第１減圧工程により圧力室１内の圧力を２０ＭＰａから１２ＭＰａに減圧する以外は実施例１と同様にして成形用樹脂を発泡させた。
Example 3
In Example 1, the pressure in the pressure chamber 1 is increased by the plunger pump 23 until the pressure becomes 20 MPa, the pressure reduction speed of the first pressure reduction step is 500 MPa / min, and the pressure in the pressure chamber 1 is reduced by the first pressure reduction step. The molding resin was foamed in the same manner as in Example 1 except that the pressure was reduced from 20 MPa to 12 MPa.
〔比較例１〕
実施例１において、プランジャーポンプ２３により圧力室１内の圧力を２０ＭＰａになるまで圧力を上げ、第１減圧工程及び第２減圧工程を設けず、圧力室１の減圧バルブ１２を開いて減圧スピード１００ＭＰａ／分にて減圧し、圧力室１内の圧力を２０ＭＰａから常圧まで一気に減圧する以外は実施例１と同様にして成形用樹脂を発泡させた。
[Comparative Example 1]
In Example 1, the pressure in the pressure chamber 1 is increased by the plunger pump 23 until the pressure becomes 20 MPa, the first pressure reducing step and the second pressure reducing step are not provided, and the pressure reducing valve 12 of the pressure chamber 1 is opened to reduce the pressure. The molding resin was foamed in the same manner as in Example 1 except that the pressure was reduced at 100 MPa / min and the pressure in the pressure chamber 1 was reduced from 20 MPa to normal pressure.
〔比較例２〕
実施例１において、第１減圧工程及び第２減圧工程を設けず、圧力室１の減圧バルブ１２を開いて減圧スピード４ＭＰａ／分にてゆっくりと減圧し、圧力室１内の圧力を２５ＭＰａから常圧まで一気に減圧する以外は実施例１と同様にして成形用樹脂を発泡させた。
[Comparative Example 2]
In Example 1, the first pressure reducing step and the second pressure reducing step are not provided, the pressure reducing valve 12 of the pressure chamber 1 is opened, and the pressure is slowly reduced at a pressure reducing speed of 4 MPa / min. The molding resin was foamed in the same manner as in Example 1 except that the pressure was reduced to a pressure all at once.
〔ドライアイスの発生状態の観察〕
実施例１、２及び３並びに比較例１及び２で用いた金属製容器３を圧力室１から取り出す際の圧力室１の内部表面及び金属製容器３の外表面にドライアイスが発生しているか否かを目視にて観察した。その結果を、表１に示す。
[Observation of dry ice generation]
Whether dry ice is generated on the inner surface of the pressure chamber 1 and the outer surface of the metal container 3 when the metal container 3 used in Examples 1, 2, and 3 and Comparative Examples 1 and 2 is taken out from the pressure chamber 1 It was visually observed whether or not. The results are shown in Table 1.
表１に示す結果から明らかなように、実施例１、２及び３で用いた圧力室１の内部表面及び金属製容器３の外表面にはドライアイスが発生しておらず、金属製容器３から発泡体を取り出し易かった。一方、比較例１及び２で用いた圧力室１の内部表面及び金属製容器３の外表面にはドライアイスが発生しており、金属製容器３から発泡体を取り出し難いだけでなく、比較例１及び２の発泡体の表面には金型により成形される突部や窪みとは異なる僅かな凹凸が部分的にみられた。 As is clear from the results shown in Table 1, no dry ice was generated on the inner surface of the pressure chamber 1 and the outer surface of the metal container 3 used in Examples 1, 2, and 3, and the metal container 3 It was easy to take out the foam. On the other hand, dry ice is generated on the inner surface of the pressure chamber 1 and the outer surface of the metal container 3 used in Comparative Examples 1 and 2, and it is not only difficult to take out the foam from the metal container 3. On the surface of the foams 1 and 2, slight irregularities different from the protrusions and depressions formed by the mold were partially seen.
〔発泡体の気泡状態の評価〕
実施例１、２及び３並びに比較例１及び２で得られた発泡体を、二等分にカットし、そのカット断面について、前述した走査型電子顕微鏡（リアルサーフェイス顕微鏡 商品名ＶＥ７８００；（株）キーエンス製）リアルサーフェイス顕微鏡（商品名ＶＥ７８００；（株）キーエンス製）による拡大観察を行った。その結果を図４（実施例１，２及び３）及び図５（比較例１及び２）に示す。また、実施例１、２及び３並びに比較例１及び２で得られた発泡体のセル壁の厚み、スキン層の厚み、セル面積及びセル密度を、上述した方法により測定した。その結果を、表１に示す。
[Evaluation of bubble state of foam]
The foams obtained in Examples 1, 2, and 3 and Comparative Examples 1 and 2 were cut into two equal parts, and the above-described scanning electron microscope (real surface microscope, trade name VE7800; Co., Ltd.) was cut. Magnification observation was performed with a real surface microscope (trade name VE7800; manufactured by Keyence Corporation). The results are shown in FIG. 4 (Examples 1, 2 and 3) and FIG. 5 (Comparative Examples 1 and 2). In addition, the cell wall thickness, skin layer thickness, cell area and cell density of the foams obtained in Examples 1, 2 and 3 and Comparative Examples 1 and 2 were measured by the methods described above. The results are shown in Table 1.
表１に示す結果から明らかなように、実施例１、２及び３で得られた発泡体は、気泡サイズが細かく、気泡が均一な超臨界発泡体であった。一方、比較例１及び２で得られた発泡体は、実施例１、２及び３で得られた発泡体に比べて、比較例１は発泡体断面において気泡同士の間に４０〜７０μｍの未発泡部分が存在し、セル密度が低いとともにセル壁の厚みが厚く、気泡が不均一であった。特に、比較例２で得られた発泡体は、気泡サイズが大きく、気泡同士の間に１００〜１２０μｍの大きな未発泡部分が存在するとともにスキン層が厚く、気泡が不均一であった。 As is clear from the results shown in Table 1, the foams obtained in Examples 1, 2, and 3 were supercritical foams having fine bubble sizes and uniform bubbles. On the other hand, the foams obtained in Comparative Examples 1 and 2 were compared with the foams obtained in Examples 1, 2 and 3, and Comparative Example 1 had a 40 to 70 μm gap between the bubbles in the foam cross section. Foamed portions were present, the cell density was low, the cell wall was thick, and the bubbles were not uniform. In particular, the foam obtained in Comparative Example 2 had a large bubble size, a large unfoamed portion of 100 to 120 μm was present between the bubbles, the skin layer was thick, and the bubbles were non-uniform.
１ 圧力室
１１ ヒーター
１２ 減圧バルブ
２ 超臨界流体供給部
２１ ボンベ
２２ 冷却器
２３ プランジャーポンプ
２４ 加熱器
３ 金属製容器
３１ 金属板
３２ 金属板
３３ 凹部
３４ ガス抜き溝
４ 歯間ブラシのブラシ部
５ 舌ブラシのブラシ部
DESCRIPTION OF SYMBOLS 1 Pressure chamber 11 Heater 12 Pressure-reducing valve 2 Supercritical fluid supply part 21 Cylinder 22 Cooler 23 Plunger pump 24 Heater 3 Metal container 31 Metal plate 32 Metal plate 33 Recess 34 Degassing groove 4 Interdental brush brush part 5 Tongue brush part
Claims (5)
圧力室内を減圧させる工程が、第１減圧工程及び第１減圧工程より後の第２減圧工程を有し、
第２減圧工程の減圧スピードが、第１減圧工程の減圧スピードよりも遅い発泡体の製造方法。 In a pressure chamber containing a molding resin, a manufacturing method for obtaining a molding resin foam comprising a step of bringing a molding resin into contact with a supercritical fluid, and a step of subsequently depressurizing the pressure chamber,
The step of depressurizing the pressure chamber includes a first depressurization step and a second depressurization step after the first depressurization step;
A method for producing a foam, wherein the pressure reduction speed of the second pressure reduction process is slower than the pressure reduction speed of the first pressure reduction process.
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| JP2008127466A (en) * | 2006-11-21 | 2008-06-05 | Teijin Chem Ltd | Foam |
| JP2010179289A (en) * | 2009-02-09 | 2010-08-19 | Kobe Steel Ltd | High-pressure treatment method and high-pressure treatment apparatus |
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| JP2003096229A (en) * | 2001-09-20 | 2003-04-03 | Mitsui Chemicals Inc | Production method of porous (co)polymer film and porous (co)polymer film produced by the method |
| JP2007332242A (en) * | 2006-06-14 | 2007-12-27 | National Institute Of Advanced Industrial & Technology | Method for producing inorganic substance polymer composite and inorganic substance polymer composite |
| JP2008127466A (en) * | 2006-11-21 | 2008-06-05 | Teijin Chem Ltd | Foam |
| JP2010179289A (en) * | 2009-02-09 | 2010-08-19 | Kobe Steel Ltd | High-pressure treatment method and high-pressure treatment apparatus |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114835939A (en) * | 2021-02-01 | 2022-08-02 | 泰星能源解决方案有限公司 | Process for producing olefin resin porous body |
| US11725090B2 (en) | 2021-02-01 | 2023-08-15 | Prime Planet Energy & Solutions, Inc. | Method for producing olefinic resin porous material |
| CN114835939B (en) * | 2021-02-01 | 2023-11-10 | 泰星能源解决方案有限公司 | Method for producing olefin resin porous body |
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