JP2006212945A - Injection, impregnation, foaming method and ultra-fine foamed body - Google Patents

Injection, impregnation, foaming method and ultra-fine foamed body Download PDF

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JP2006212945A
JP2006212945A JP2005028559A JP2005028559A JP2006212945A JP 2006212945 A JP2006212945 A JP 2006212945A JP 2005028559 A JP2005028559 A JP 2005028559A JP 2005028559 A JP2005028559 A JP 2005028559A JP 2006212945 A JP2006212945 A JP 2006212945A
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cavity
injection
mold
foam
side mold
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JP4162662B2 (en
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Yukio Mende
幸雄 免出
Mitsuaki Yamachika
光昭 山近
Hironari Arita
大就 有田
Masahiro Takatsuka
雅弘 高塚
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Japan Steel Works Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To produce foamed body in which ultra-fine foamed cells are dispersed uniformly by making a molten amorphous resin injected and packed in a cavity be impregnated with an inert gas. <P>SOLUTION: A cavity side mold 15 and a core side mold 16 which can change the volume of the cavity 14 are used. After the molten amorphous resin weighed by an injection unit 1 is injected and packed in the cavity 14 of a mold-clamped packing volume V<SB>2</SB>, in a process for cooling the resin to its apparent glass transition temperature, the core side mold 16 is moved in the mold opening direction to form a clearance S between it and an unfoamed molding P<SB>1</SB>. Through the clearance S and at least two pin holes 17 in the cavity side mold 15, the inert gas in a super critical fluid state is injected into both surfaces of the unfoamed molding P<SB>1</SB>to be impregnated in a short time. Next, by discharging the inert gas in the cavity 14 and moving the core side mold 16 in the mold opening direction to enlarge the cavity to a foamed molding volume V<SB>1</SB>, an ultra-fine foamed molding is produced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、超微細発泡セルを有する高精度の発泡成形体を連続的に成形することができる射出含浸発泡成形方法および超微細発泡成形体に関するものである。   The present invention relates to an injection-impregnated foam-molding method and an ultra-fine foam-molded product capable of continuously molding a highly accurate foam-molded product having ultrafine foam cells.

特許文献１（特開２００３−４９０１８号公報）には、ＯＡ機器、電気機器、自動車部品等に用いられる微細発泡セルを有する発泡成形体の製造方法の例として、熱可塑性樹脂に超臨界流体状の不活性ガスを高圧・高温下で含浸させたのち、圧力を開放して脱ガスするバッチ状発泡成形方法とともに、次に説明する射出発泡成形方法が開示されている。   In Patent Document 1 (Japanese Patent Laid-Open No. 2003-49018), as an example of a method for producing a foamed molded article having fine foam cells used for OA equipment, electrical equipment, automobile parts, etc., a thermoplastic resin is supercritical fluid. In addition to a batch-like foam molding method in which an inert gas is impregnated under high pressure and high temperature and then degassed by releasing the pressure, an injection foam molding method described below is disclosed.

特許文献１に開示された射出発泡成形方法は、射出ユニットにおいて熱可塑性樹脂と超臨界流体状態の不活性ガスとを混練・溶融した溶融樹脂を、キャビティ容積を縮小した状態で型締めされた金型のキャビティ内へ射出・充填したのち、前記キャビティの容積を拡大させるとともに急冷を行うことにより、溶融樹脂に含浸された前記不活性ガスによる発泡セルを育成させて発泡成形体を連続的に製造する。
特開２００３−４９０１８号公報 The injection foam molding method disclosed in Patent Document 1 is a mold in which a molten resin obtained by kneading and melting a thermoplastic resin and an inert gas in a supercritical fluid state in an injection unit is clamped with a cavity volume reduced. After injection and filling into the mold cavity, expand the volume of the cavity and perform rapid cooling to grow the foam cells by the inert gas impregnated with the molten resin and continuously produce the foam moldings To do.
JP 2003-49018 A

上記特許文献１に開示された射出発泡成形方法では、射出ユニットにおいて熱可塑性樹脂と超臨界流体状態の不活性ガスとを混練・溶融して計量し、計量された不活性ガスが含浸された溶融樹脂をキャビティに射出・充填する際に、該溶融樹脂がスプルを通過してキャビティ内に射出された時点で急激に樹脂圧力が降下して発泡が始まり、発泡しながらキャビティ内に充填される。そのため、充填途中において発泡に好適な圧力制御および温度制御を行うことができず、セル径の大きな気泡が発生したり、発生した気泡同士が合体してガス抜けしてしまい、超微細発泡セルを有する発泡成形体を製造することができないという問題点があった。   In the injection foam molding method disclosed in Patent Document 1 above, a thermoplastic resin and supercritical fluid state inert gas are kneaded and melted and measured in an injection unit, and a melt in which the measured inert gas is impregnated. When injecting and filling the resin into the cavity, when the molten resin passes through the sprue and is injected into the cavity, the resin pressure suddenly drops and foaming starts, and the cavity is filled while foaming. Therefore, pressure control and temperature control suitable for foaming cannot be performed in the middle of filling, and bubbles with large cell diameters are generated, or the generated bubbles are coalesced to escape gas, resulting in an ultrafine foam cell. There was a problem that it was not possible to produce a foamed molded product having the same.

本発明は、上記従来の技術の有する問題点に鑑みてなされたものであって、キャビティ内に射出・充填された溶融樹脂に対する圧力制御および温度制御を行うことができ、超微細発泡セルが均一に分散した発泡成形体を製造できる射出含浸発泡成形方法および超微細発泡成形体を提供することを目的とするものである。   The present invention has been made in view of the above-described problems of the prior art, and can perform pressure control and temperature control on the molten resin injected and filled in the cavity, so that the ultrafine foam cell is uniform. It is an object of the present invention to provide an injection-impregnated foam-molding method and an ultra-fine foam-molded product that can produce a foam-molded product dispersed in a foam.

上記目的を達成するため、本発明に係る射出含浸発泡成形方法は、キャビティ側金型およびコア側金型からなり、キャビティの容積を、超微細発泡成形体の外面を規制する発泡成形体容積と、前記超微細発泡成形体に見合う大きさの未発泡成形体の外面を規制する充填容積とに変化できる射出発泡成形金型を用いた超微細発泡成形体の製造方法において、前記射出発泡成形金型を前記充填容積にて型締めする型締工程と、前記充填容積のキャビティへ計量された溶融非晶性樹脂を射出・充填して未発泡成形体を形成する射出工程と、前記射出工程ののち、前記未発泡成形体を形成する溶融非晶性樹脂を見掛けガラス転位温度まで冷却する途中に、前記コア側金型を型開き方向へ移動させて、前記未発泡成形体と前記コア側金型との間に微小な隙間を形成して前記隙間に超臨界流体状態の不活性ガスを注入するとともに、前記キャビティ側金型の前記未発泡成形体との対向面に互いに間隔をおいて配設された複数の注入口より超臨界流体状態の不活性ガスを注入して、前記未発泡成形体に前記不活性ガスを含浸させる冷却・含浸工程と、前記冷却・含浸工程ののち、前記キャビティ内から前記不活性ガスを排気することにより急速に減圧して気泡を発生させるとともに、前記コア側金型をさらに型開き方向へ移動させて前記キャビティの容積を前記発泡成形体容積に拡大させて超微細発泡成形体を発泡成形する発泡工程と、を有することを特徴とするものである。   In order to achieve the above object, an injection impregnation foam molding method according to the present invention comprises a cavity side mold and a core side mold, and the volume of the cavity is defined as a foam molded body volume that regulates the outer surface of the ultrafine foam molded body. In the method for producing an ultrafine foam molded article using an injection foam mold that can be changed to a filling volume that regulates the outer surface of an unfoamed molded article having a size suitable for the ultrafine foam molded article, A mold clamping process for clamping the mold at the filling volume, an injection process for injecting and filling a measured amount of the molten amorphous resin into a cavity of the filling volume, and forming an unfoamed molded body; and Then, while the molten amorphous resin forming the unfoamed molded body is apparently cooled to the glass transition temperature, the core-side mold is moved in the mold opening direction, and the unfoamed molded body and the core-side mold are moved. Minute between the mold A plurality of inlets that are spaced apart from each other on the surface of the cavity-side mold facing the unfoamed molded body and injecting an inert gas in a supercritical fluid state into the gap. A cooling / impregnation step in which an inert gas in a supercritical fluid state is injected to impregnate the unfoamed molded body with the inert gas, and after the cooling / impregnation step, the inert gas is injected from the cavity. By evacuating, the pressure is rapidly reduced to generate bubbles, and the core side mold is further moved in the mold opening direction to expand the volume of the cavity to the volume of the foamed molded product to foam the ultrafine foamed molded product. And a foaming step for molding.

また、超微細発泡成形体は、本発明に係る上記射出含浸発泡成形方法のいずれかによって製造されたものであって、スキン層を有し、平均セル径が２〜５μｍ、セル数が１０10個／ｃｍ3 以上であることを特徴とする。 The ultrafine foam molded article is produced by any one of the above-described injection impregnation foam molding methods according to the present invention, has a skin layer, has an average cell diameter of 2 to 5 μm, and a cell number of 10 10. It is characterized by being at least 3 pieces / cm 3 .

本発明は上述のとおり構成されているので、次に記載するような効果を奏する。   Since the present invention is configured as described above, the following effects can be obtained.

キャビティ内に射出・充填された溶融非晶性樹脂の冷却固化過程において、超臨界流体状態の不活性ガスが効率良く短時間で含浸されるので、成形サイクル時間が短縮される。   In the cooling and solidification process of the molten amorphous resin injected and filled into the cavity, the inert gas in the supercritical fluid state is efficiently impregnated in a short time, so that the molding cycle time is shortened.

また、キャビティ内の樹脂圧力および樹脂温度を発泡に最適な樹脂圧力および樹脂温度に制御することができるので、超微細な発泡セルが均一に分散された超微細発泡成形体を安定して製造することができる。   In addition, since the resin pressure and resin temperature in the cavity can be controlled to the optimum resin pressure and resin temperature for foaming, it is possible to stably produce an ultrafine foam molded article in which ultrafine foam cells are uniformly dispersed. be able to.

先ず、本発明の実施に用いる射出含浸発泡成形装置の一例について説明する。   First, an example of an injection impregnation foam molding apparatus used for carrying out the present invention will be described.

本例による射出含浸発泡成形装置は、図１に示すように、ベース７上に配設された射出ユニット１および型締装置１０と、不活性ガス供給手段２０とを備えている。   As shown in FIG. 1, the injection impregnation foam molding apparatus according to this example includes an injection unit 1 and a mold clamping device 10 disposed on a base 7, and an inert gas supply means 20.

射出ユニット１は、図示しない加熱手段によって加熱されるシリンダ２と、シリンダ２内に回転自在かつ軸方向へ進退自在に配設されたスクリュ（不図示）と、前記スクリュを回転させるとともに軸方向へ進退させる駆動機構３とを有し、ホッパ４より供給された非晶性樹脂を混練・溶融して計量する計量機能（可塑化機能）と、ノズル５をスプル９にノズルタッチさせて、計量された溶融樹脂をキャビティ１４へ射出・充填する射出機能とを備えている。   The injection unit 1 includes a cylinder 2 heated by a heating means (not shown), a screw (not shown) disposed in the cylinder 2 so as to be rotatable and movable back and forth in the axial direction, and rotating the screw in the axial direction. It has a drive mechanism 3 for advancing and retreating, and a measuring function (plasticizing function) for kneading and melting the amorphous resin supplied from the hopper 4 and measuring the nozzle 5 by touching the spru 9 with the nozzle 9 And an injection function for injecting and filling the molten resin into the cavity 14.

型締装置１０は、キャビティ側金型１５が取り付けられる固定盤１１と、コア側金型１６が取り付けられる可動盤１２と、可動盤１２を軸方向へ移動自在に案内する複数のタイバー８と、可動盤１２とともにコア側金型１６をキャビティ側金型１５に対して進退させて型締めおよび型開きする型開閉機構（不図示）とを備えている。   The mold clamping device 10 includes a stationary platen 11 to which the cavity-side die 15 is attached, a movable platen 12 to which the core-side die 16 is attached, a plurality of tie bars 8 that guide the movable platen 12 so as to be movable in the axial direction, A mold opening / closing mechanism (not shown) that moves the core-side mold 16 forward and backward with respect to the cavity-side mold 15 and opens and closes the mold together with the movable platen 12 is provided.

ここで、型開閉機構は、キャビティ側金型１５の凹部１５ａと凹部１５ａに嵌合されたコア側金型１６のコア部１６ａとで形成されるキャビティ１４の容積を超微細発泡成形体の外面を規制する発泡成形体容積Ｖ1 と前記超微細発泡成形体に見合う大きさ（容積）の未発泡成形体の外面を規制する充填容積Ｖ2 とに変化できるように構成されたものであれば、トグル式、直圧式または電動式等のいずれでもよい。 Here, the mold opening / closing mechanism sets the volume of the cavity 14 formed by the concave portion 15a of the cavity side mold 15 and the core portion 16a of the core side mold 16 fitted in the concave portion 15a to the outer surface of the ultrafine foam molded body. As long as it is configured to be able to change to a foam volume V 1 that regulates the volume and a filling volume V 2 that regulates the outer surface of the non-foamed mold having a size (volume) suitable for the ultrafine foam molded body. Any of a toggle type, a direct pressure type or an electric type may be used.

キャビティ側金型１５には、凹部１５ａのコア側金型１６に対向する底壁にキャビティ面から固定盤１１側へ貫通する複数のピン孔１７が互いに間隔をおいて設けられているとともに、複数のピン孔１７と交差する流路１８が設けられている。そして各ピン孔１７はその軸方向略中間部位に設けられた開口部によって流路１８に連通されている。   The cavity side mold 15 is provided with a plurality of pin holes 17 penetrating from the cavity surface to the fixed platen 11 side in the bottom wall of the recess 15a facing the core side mold 16 at intervals. A flow path 18 intersecting with the pin hole 17 is provided. Each pin hole 17 communicates with the flow path 18 through an opening provided at a substantially intermediate portion in the axial direction.

各ピン孔１７にはそれぞれピン１７ａが軸方向へ移動自在に嵌挿されており、各ピン１７ａは固定盤１１側に配設された流体圧シリンダ等のアクチュエータ１７ｃによって、先端がキャビティ面と同一面になる閉鎖位置と、前記開口部が開いて流路１８と連通する連通位置とに移動できるようになっている。   A pin 17a is fitted in each pin hole 17 so as to be movable in the axial direction, and each pin 17a is flush with the cavity surface by an actuator 17c such as a fluid pressure cylinder disposed on the fixed platen 11 side. It is possible to move between a closed position that becomes a surface and a communication position where the opening portion opens and communicates with the flow path 18.

他方、コア側金型１６は、キャビティ側金型１５の凹部１５ａに摺動自在に気密状態で嵌合するコア部１６ａを有し、コア部１６ａにはエジェクタのエジェクタプレート１３ｂに配設された複数のエジェクタピン１３ａが軸方向へ移動自在に嵌挿されている。また、コア側金型１６には、コア部１６ａの先端面（キャビティ面）に一端側が開口する注入流路１９ａが設けられているとともに、注入流路１９ａとは反対側の離間した部位に一端側が開口する排出流路１９ｂが設けられている。   On the other hand, the core-side mold 16 has a core portion 16a that is slidably fitted in the concave portion 15a of the cavity-side die 15 in an airtight state, and is disposed on an ejector plate 13b of the ejector. A plurality of ejector pins 13a are inserted so as to be movable in the axial direction. Further, the core side mold 16 is provided with an injection channel 19a having one end opened at the tip surface (cavity surface) of the core part 16a, and one end at a spaced apart side opposite to the injection channel 19a. A discharge channel 19b that is open on the side is provided.

なお、キャビティ側金型１５およびコア側金型１６は、冷却回路（不図示）を有し、この冷却回路に温調された冷却媒体を供給することで、所定の冷却速度で冷却できる。また、ヒータ等の加熱手段を併設しておけば、冷却と加熱とを選択的に行うことができる。   The cavity side mold 15 and the core side mold 16 have a cooling circuit (not shown), and can be cooled at a predetermined cooling rate by supplying a temperature-controlled cooling medium to the cooling circuit. Further, if a heating means such as a heater is provided, cooling and heating can be selectively performed.

不活性ガス供給装置２０は、ボンベ３０に貯留された炭酸ガスや窒素ガス等の不活性ガスを臨界圧力および臨界温度以上にして超臨界流体を生成する超臨界流体発生装置２１と、流量計２２、開閉バルブ２３、流量調整弁２４が介在された供給管路２５と、供給管路２５から分岐する一対の分岐管路２６、２７とを有し、一方の分岐管路２６は、コア側金型１６の注入流路１９ａに接続されているとともに他方の分岐管路２７はキャビティ側金型１５の流路１８の注入口１８ａに接続されている。   The inert gas supply device 20 includes a supercritical fluid generator 21 that generates a supercritical fluid by setting an inert gas such as carbon dioxide gas and nitrogen gas stored in the cylinder 30 to a critical pressure and a critical temperature or higher, and a flow meter 22. , A supply line 25 having an open / close valve 23 and a flow rate adjusting valve 24 interposed therein, and a pair of branch lines 26 and 27 branched from the supply line 25, one of the branch lines 26 being a core side metal The other branch conduit 27 is connected to the injection channel 19 a of the mold 16 and is connected to the injection port 18 a of the channel 18 of the cavity-side mold 15.

次に、本発明に係る射出含浸発泡成形方法の一実施の形態について説明する。   Next, an embodiment of an injection impregnation foam molding method according to the present invention will be described.

（１）図１に示すように、ノズル５をノズルタッチさせた射出ユニット１において、スクリュを回転させてホッパ４より非晶性樹脂材料を供給して混練・溶融することによって溶融非晶性樹脂を計量（可塑化）する。   (1) As shown in FIG. 1, in the injection unit 1 in which the nozzle 5 is touched with the nozzle, the amorphous resin material is supplied from the hopper 4 by rotating the screw, and kneaded and melted to melt the molten amorphous resin. Weigh (plasticize).

（２）上記（１）の計量工程ののち、固定盤１１に取り付けたキャビティ側金型１５に対して可動盤１２に取り付けたコア側金型１６を前進させて、キャビティ１４の容積を、超微細発泡成形体に見合う大きさの未発泡成形体の外面を規制する充填容積Ｖ2 での型締めを行う。 (2) After the weighing step (1), the core-side mold 16 attached to the movable platen 12 is advanced relative to the cavity-side die 15 attached to the fixed platen 11, and the volume of the cavity 14 is increased. Clamping is performed at a filling volume V 2 that regulates the outer surface of the unfoamed molded product having a size suitable for the fine foamed molded product.

（３）上記（２）の型締め工程ののち、図２に示すように、射出ユニット１におけるスクリュを前進させて計量された溶融非晶性樹脂を充填容積Ｖ2 のキャビティ１４内へ射出・充填する。 (3) After the mold clamping step (2) above, as shown in FIG. 2, the molten amorphous resin measured by advancing the screw in the injection unit 1 is injected into the cavity 14 of the filling volume V 2. Fill.

本工程において、溶融非晶性樹脂は充填容積Ｖ2 のキャビティ１４の全域に充填されて樹脂圧力が高圧になる。 In this step, the molten amorphous resin is filled in the entire area of the cavity 14 having the filling volume V 2 and the resin pressure becomes high.

（４）上記（３）の射出工程ののち、金型に内設された冷却回路に温調した冷却媒体を流して冷却を開始し、キャビティ１４内の溶融非晶性樹脂温度が見掛けガラス転位点Ｔｇから＋５℃〜＋２０℃の範囲に下降した時点で、図３に示すように、可動盤１２とともにコア側金型１６を後退（コアバック）させてコア側金型１６とキャビティ１４内の未発泡成形体Ｐ1 との間に微小な隙間Ｓを発生させる。ついで、超臨界流体状態の不活性ガスをコア側金型１６の注入流路１９ａを介して隙間Ｓの部分へ導入するとともに、キャビティ側金型１５の複数のピン１７ａを後退させて複数のピン孔１７と流路１８との連通部を開放し、前記不活性ガスを未発泡成形体Ｐ1 と凹部１５ａの底壁面との間へ供給する。 (4) After the injection process of (3) above, cooling is started by flowing a temperature-controlled cooling medium in a cooling circuit provided in the mold, and the molten amorphous resin temperature in the cavity 14 is apparently glass dislocation. When the temperature falls from the point Tg to a range of + 5 ° C. to + 20 ° C., as shown in FIG. generating a small gap S between the unfoamed molded article P 1. Next, an inert gas in a supercritical fluid state is introduced into the gap S through the injection flow path 19a of the core-side mold 16, and the plurality of pins 17a of the cavity-side mold 15 are moved backward to form a plurality of pins. opens the communicating portion between the hole 17 and the flow path 18, is supplied to between the bottom wall surface of said inert gas unfoamed molded article P 1 and the recess 15a.

なお、含浸開始時における未発泡成形体Ｐ1 のキャビティ金型側面およびコア側金型側面と不活性ガスとの接触状態を図７に示す。図７の（ａ）に示すように、未発泡成形体Ｐ1 のコア側金型側面は全面が不活性ガスと接触している。他方、図７の（ｂ）に示すように、未発泡成形体Ｐ1 のキャビティ側金型側面は、複数のピン孔１７より注入された不活性ガスが複数の円形接触部から含浸が始まり、そののち成長して互いに隣接する円形接触部がオーバーラップして全面に拡がる。以上の説明より明らかなように、本実施の形態では、複数のピン孔１７により、キャビティ側金型１５の未発泡成形体Ｐ1 との対向面に互いに間隔をおいて配設された複数の注入口が構成されている。 In addition, the contact state of the cavity mold side surface and the core side mold side surface of the unfoamed molded body P 1 and the inert gas at the start of impregnation is shown in FIG. As shown in FIG. 7 (a), the core side mold side of the unfoamed molded article P 1 is the entire surface in contact with an inert gas. On the other hand, as shown in FIG. 7B, the cavity side mold side surface of the non-foamed molded body P 1 is impregnated with the inert gas injected from the plurality of pin holes 17 from the plurality of circular contact portions, After that, the circular contact portions adjacent to each other grow and overlap to spread over the entire surface. As is clear from the above description, in the present embodiment, a plurality of pin holes 17 are used to provide a plurality of spaces disposed on the surface of the cavity-side mold 15 facing the unfoamed molded body P 1 at intervals. An inlet is configured.

（５）上記（４）の冷却・含浸工程の開始から所定の冷却時間が経過し、未発泡成形体Ｐ1 の樹脂温度がガラス転位温度Ｔｇに降下した時点で、シーケンスバルブ２９を開けてキャビティ１４内の不活性ガスを開放（排気）して急激に減圧するとともに、可動盤１２とともにコア側金型１６を後退させてキャビティ１４を発泡成形体容積Ｖ1 まで拡大する。 (5) When a predetermined cooling time has elapsed from the start of the cooling / impregnation step of (4) and the resin temperature of the unfoamed molded product P 1 has dropped to the glass transition temperature Tg, the sequence valve 29 is opened and the cavity is opened. The inert gas in 14 is released (exhaust) to rapidly reduce the pressure, and the core side mold 16 is retracted together with the movable platen 12 to expand the cavity 14 to the foam molded body volume V 1 .

本工程において、コア側金型１６の後退速度を発泡中の成形体の厚み増大速度よりも低速に制御して、発泡圧力がコア側金型１６にかかるように後退させる方が表面転写性が良好になる。   In this step, the surface transferability is better when the retreating speed of the core side mold 16 is controlled to be lower than the thickness increasing speed of the molded body being foamed so that the foaming pressure is applied to the core side mold 16. Become good.

（６）上記（５）の発泡工程ののち、所定時間経過したら、図６に示すように、可動盤１２とともにコア側金型１６をさらに後退させて型開きし、エジェクタ（不図示）の突き出しピン１３を突き出すことによって超微細発泡成形体Ｐ2 を離型する。 (6) After the foaming step of (5) above, when a predetermined time has elapsed, as shown in FIG. 6, the core side mold 16 is further retracted together with the movable platen 12 to open the mold, and an ejector (not shown) is projected. The ultrafine foam molded article P 2 is released by protruding the pin 13.

本工程において、キャビティ内の樹脂圧力は、急激に降下して不活性ガスは過飽和状態になり、発泡核が形成されて気泡へと成長する。   In this step, the resin pressure in the cavity drops rapidly, the inert gas becomes supersaturated, foam nuclei are formed, and grow into bubbles.

なお、微細な発泡セルを形成するには、温度制御および圧力制御が必要である。   In addition, in order to form a fine foam cell, temperature control and pressure control are required.

また、発泡セル数の増大や発泡セルを均一に分散させるには、射出ユニット１において発泡核剤を添加して溶融非晶性樹脂中に分散させるとよい。   Further, in order to increase the number of foam cells or to uniformly disperse the foam cells, it is preferable to add a foam nucleating agent in the injection unit 1 and disperse it in the molten amorphous resin.

また、発泡工程中は、不活性ガス封入圧力を保持することが必要であり、ガス圧を所定の保持圧力に維持するため追加供給するとよい。   Further, during the foaming step, it is necessary to maintain the inert gas filling pressure, and it is preferable to additionally supply the gas pressure in order to maintain the gas pressure at a predetermined holding pressure.

図８は、本発明に係る射出含浸発泡成形方法における冷却・含浸工程の樹脂温度範囲を従来例と比較して示すグラフである。図８に示すように、本発明に係る射出含浸発泡成形方法の含浸工程の樹脂温度範囲（本プロセスの含浸領域）は、非晶性樹脂ではＴｇから＋５℃〜＋２０℃の範囲であり、特許文献１に開示された発泡成形方法とは大きく異なっている。   FIG. 8 is a graph showing the resin temperature range of the cooling / impregnation step in the injection impregnation foam molding method according to the present invention in comparison with the conventional example. As shown in FIG. 8, the resin temperature range (impregnation region of this process) in the impregnation step of the injection impregnation foam molding method according to the present invention is a range of + 5 ° C. to + 20 ° C. from Tg in an amorphous resin. This is greatly different from the foam molding method disclosed in Document 1.

高品質の超微細発泡成形体を得るには、発泡セル形成においては、温度条件とともに冷却速度も重要となる。ガラス転位温度までの冷却速度は０．５℃／ｓｅｃ未満が好ましく、不活性ガス含浸後の冷却速度は０．５℃／ｓｅｃ〜１０℃／ｓｅｃの範囲が望ましい。冷却速度が１０℃／ｓｅｃより速い場合は、発泡セルが成長せずに無発泡の場合が生じ、逆に０．５℃／ｓｅｃより遅い場合は、発泡セルが成長して５μｍ以上になってしまう。   In order to obtain a high-quality ultrafine foamed molded article, in the formation of foamed cells, the cooling rate is important as well as the temperature conditions. The cooling rate to the glass transition temperature is preferably less than 0.5 ° C./sec, and the cooling rate after impregnation with the inert gas is preferably in the range of 0.5 ° C./sec to 10 ° C./sec. When the cooling rate is faster than 10 ° C / sec, the foamed cell does not grow and there is a case of no foaming. Conversely, when it is slower than 0.5 ° C / sec, the foamed cell grows to become 5 μm or more. End up.

また、冷却時間は２０秒〜５分の範囲が適切である。圧力開放時の減圧速度は１０ＭＰａ／ｓｅｃ〜１００ＭＰａ／ｓｅｃの範囲が好ましく、３０ＭＰａ／ｓｅｃ〜７０ＭＰａ／ｓｅｃの範囲がより好適である。   The cooling time is suitably in the range of 20 seconds to 5 minutes. The pressure reduction rate when releasing the pressure is preferably in the range of 10 MPa / sec to 100 MPa / sec, and more preferably in the range of 30 MPa / sec to 70 MPa / sec.

本発明において製造された超微細発泡成形体は、全面にスキン層が形成されており、平均セル径２〜５μｍ、セル密度１０10個／ｃｍ3 以上の超微細発泡セルが均一に分散されている。 The ultrafine foam molded article produced in the present invention has a skin layer formed on the entire surface, and ultrafine foam cells having an average cell diameter of 2 to 5 μm and a cell density of 10 10 cells / cm 3 or more are uniformly dispersed. Yes.

さらに、非晶性樹脂原料としては、ポリカーボネート（ＰＣ）、ポリメチルメタクリレート（ＰＭＭＡ）、ポリスチレン（ＰＳ）等の非結晶性樹脂が好ましい。   Furthermore, the amorphous resin material is preferably an amorphous resin such as polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS).

本発明の実施に用いる射出含浸発泡成形装置の主要部を示す説明図である。It is explanatory drawing which shows the principal part of the injection impregnation foam molding apparatus used for implementation of this invention. 本発明に係る射出含浸発泡成形方法の射出・充填工程を示す説明図である。It is explanatory drawing which shows the injection | emission and filling process of the injection impregnation foam molding method which concerns on this invention. 本発明に係る射出含浸発泡成形方法の一工程である冷却・含浸工程のうち、コア側金型と射出・充填された溶融樹脂との間に微小な隙間を発生させた状態を示す説明図である。It is explanatory drawing which shows the state which generate | occur | produced the micro clearance gap between the core side metal mold | die and the injection-filled molten resin among the cooling and impregnation processes which are one process of the injection impregnation foam molding method which concerns on this invention. is there. 本発明に係る射出含浸発泡成形方法の一工程である冷却・含浸工程のうち、不活性ガスの含浸中の状態を示す説明図である。It is explanatory drawing which shows the state in the impregnation of an inert gas among the cooling and impregnation processes which are one process of the injection impregnation foam molding method which concerns on this invention. 本発明に係る射出含浸発泡成形方法の一工程である発泡工程を示す説明図である。It is explanatory drawing which shows the foaming process which is one process of the injection impregnation foam molding method which concerns on this invention. 本発明に係る射出含浸発泡成形方法の一工程である超微細発泡成形体の取り出し工程を示す説明図である。It is explanatory drawing which shows the taking-out process of the ultrafine foam molded object which is one process of the injection impregnation foam molding method which concerns on this invention. 本発明に係る射出含浸発泡成形方法の冷却・含浸工程のうち、含浸開始時における未発泡成形体と不活性ガスとの接触状態を示し、（ａ）はコア側金型側面の接触状態を示す説明図、（ｂ）はキャビティ側金型側面の接触状態を示す説明図である。In the cooling / impregnation step of the injection impregnation foam molding method according to the present invention, the contact state between the unfoamed molded body and the inert gas at the start of impregnation is shown, and (a) shows the contact state of the side surface of the core side mold. Explanatory drawing, (b) is explanatory drawing which shows the contact state of the cavity side metal mold | die side surface. 本発明に係る射出含浸発泡成形方法の冷却・含浸工程における樹脂温度の範囲を従来例と比較して示すグラフである。It is a graph which shows the range of the resin temperature in the cooling and impregnation process of the injection impregnation foam molding method which concerns on this invention compared with a prior art example.

符号の説明Explanation of symbols

１ 射出ユニット
２ シリンダ
３ 駆動機構
４ ホッパ
５ ノズル
６ スライダ
７ ベース
８ タイバー
９ スプル
１０ 型締装置
１１ 固定盤
１２ 可動盤
１４ キャビティ
１５ キャビティ側金型
１６ コア側金型
１７ ピン孔
１７ａ ピン
１８ 流路
１９ａ 注入流路
１９ｂ 排出流路
２０ 不活性ガス供給装置
２１ 超臨界ガス発生装置
２２ 流量計
２３ 開閉バルブ
２４ 流量調整弁
２５ 供給管路
２６、２７ 分岐管路
２８ バルブ
２９ シーケンスバルブ DESCRIPTION OF SYMBOLS 1 Injection unit 2 Cylinder 3 Drive mechanism 4 Hopper 5 Nozzle 6 Slider 7 Base 8 Tie bar 9 Sprue 10 Clamping device 11 Fixed platen 12 Movable platen 14 Cavity 15 Cavity side die 16 Core side die 17 Pin hole 17a Pin 18 Flow path 19a Injecting flow path 19b Discharging flow path 20 Inert gas supply device 21 Supercritical gas generator 22 Flow meter 23 Open / close valve 24 Flow rate adjusting valve 25 Supply line 26, 27 Branch line 28 Valve 29 Sequence valve

Claims (6)

キャビティ側金型(１５)およびコア側金型（１６）からなり、キャビティ（１４）の容積を、超微細発泡成形体（Ｐ2 ）の外面を規制する発泡成形体容積（Ｖ1 ）と、前記超微細発泡成形体に見合う大きさの未発泡成形体（Ｐ1 ）の外面を規制する充填容積（Ｖ2 ）とに変化できる射出発泡成形金型を用いた超微細発泡成形体の製造方法において、
前記射出発泡成形金型を前記充填容積にて型締めする型締工程と、
前記充填容積のキャビティへ計量された溶融非晶性樹脂を射出・充填して未発泡成形体（Ｐ1 ）を形成する射出工程と、
前記射出工程ののち、前記未発泡成形体を形成する溶融非晶性樹脂を見掛けガラス転位温度まで冷却する途中に、前記コア側金型を型開き方向へ移動させて、前記未発泡成形体と前記コア側金型との間に微小な隙間（Ｓ）を形成して前記隙間に超臨界流体状態の不活性ガスを注入するとともに、前記キャビティ側金型の前記未発泡成形体との対向面に互いに間隔をおいて配設された複数の注入口より超臨界流体状態の不活性ガスを注入して、前記未発泡成形体に前記不活性ガスを含浸させる冷却・含浸工程と、
前記冷却・含浸工程ののち、前記キャビティ内から前記不活性ガスを排気することにより急速に減圧して気泡を発生させるとともに、前記コア側金型をさらに型開き方向へ移動させて前記キャビティの容積を前記発泡成形体容積に拡大させて超微細発泡成形体を発泡成形する発泡工程と、
を有することを特徴とする射出含浸発泡成形方法。 A cavity side mold (15) and a core side mold (16), and the volume of the cavity (14) is a foam molded body volume (V 1 ) for regulating the outer surface of the ultrafine foam molded body (P 2 ); Method for producing ultrafine foam molded article using injection foam molding die capable of changing to filling volume (V 2 ) for regulating the outer surface of unfoamed molded article (P 1 ) of a size suitable for the ultrafine foam molded article In
A mold clamping step of clamping the injection foaming mold with the filling volume;
An injection step of injecting and filling a measured amount of molten amorphous resin into the filling volume cavity to form an unfoamed molded article (P 1 );
After the injection step, while the molten amorphous resin forming the unfoamed molded body is apparently cooled to the glass transition temperature, the core side mold is moved in the mold opening direction, and the unfoamed molded body and A minute gap (S) is formed between the core side mold and an inert gas in a supercritical fluid state is injected into the gap, and the cavity side mold faces the unfoamed molded body. A cooling / impregnation step of injecting an inert gas in a supercritical fluid state from a plurality of injection ports arranged at intervals from each other, and impregnating the unfoamed molded body with the inert gas;
After the cooling / impregnation step, the inert gas is exhausted from the cavity to rapidly reduce the pressure to generate bubbles, and the core-side mold is further moved in the mold opening direction to increase the volume of the cavity. Expanding the foamed molded body volume to foam the ultrafine foamed molded body,
An injection impregnated foam molding method characterized by comprising: 前記冷却・含浸工程における前記コア側金型の型開き方向へ移動開始時の前記未発泡成形体の温度は、見掛けガラス転位温度（Ｔｇ）から＋５℃〜＋２０℃の範囲であることを特徴とする請求項１記載の射出含浸発泡成形方法。   The temperature of the unfoamed molded body at the start of movement in the mold opening direction of the core side mold in the cooling / impregnation step is in the range of + 5 ° C. to + 20 ° C. from the apparent glass transition temperature (Tg). The injection impregnation foam molding method according to claim 1. 前記発泡工程において、前記冷却速度は、０．５℃／ｓｅｃ〜１０℃／ｓｅｃの範囲であることを特徴とする請求項１または２記載の射出含浸発泡成形方法。   The injection impregnation foam molding method according to claim 1 or 2, wherein, in the foaming step, the cooling rate is in a range of 0.5 ° C / sec to 10 ° C / sec. 前記発泡工程において、前記減圧の減圧速度は、１０ＭＰａ／ｓｅｃ〜１００ＭＰａ／ｓｅｃの範囲であることを特徴とする請求項１ないし３いずれかに記載の射出含浸発泡成形方法。   The injection impregnation foam molding method according to any one of claims 1 to 3, wherein, in the foaming step, the decompression speed of the decompression is in a range of 10 MPa / sec to 100 MPa / sec. 前記超臨界流体状態の不活性ガスは、超臨界流体状態の二酸化炭素または窒素であることを特徴とする請求項１ないし４いずれかに記載の射出含浸発泡成形方法。   The injection impregnation foam molding method according to any one of claims 1 to 4, wherein the inert gas in the supercritical fluid state is carbon dioxide or nitrogen in the supercritical fluid state. 請求項１〜６いずれかに記載の射出含浸発泡成形方法によって製造したものであって、スキン層を有し、平均セル径が２〜５μｍ、セル数が１０10個／ｃｍ3 以上であることを特徴とする超微細発泡成形体。 It is manufactured by the injection impregnation foam molding method according to any one of claims 1 to 6, having a skin layer, an average cell diameter of 2 to 5 µm, and a number of cells of 10 10 cells / cm 3 or more. Ultra-fine foam molded product characterized by
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012060392A1 (en) 2010-11-01 2012-05-10 東洋紡績株式会社 Polyamide resin composition, expanded polyamide resin molding, and automotive resin molding
CN112146060A (en) * 2020-09-27 2020-12-29 安徽工业大学 Low-melting-point alloy phase-change heat dissipation LED automobile headlamp
WO2020262314A1 (en) 2019-06-28 2020-12-30 東洋紡株式会社 Polyamide resin composition for foam molding and foam molded body

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012060392A1 (en) 2010-11-01 2012-05-10 東洋紡績株式会社 Polyamide resin composition, expanded polyamide resin molding, and automotive resin molding
US9447575B2 (en) 2010-11-01 2016-09-20 Toyobo Co., Ltd. Polyamide resin composition, expanded polyamide resin molding, and automotive resin molding
WO2020262314A1 (en) 2019-06-28 2020-12-30 東洋紡株式会社 Polyamide resin composition for foam molding and foam molded body
KR20220029552A (en) 2019-06-28 2022-03-08 도요보 가부시키가이샤 Polyamide resin composition for foam molding and expanded molded article
CN112146060A (en) * 2020-09-27 2020-12-29 安徽工业大学 Low-melting-point alloy phase-change heat dissipation LED automobile headlamp
CN112146060B (en) * 2020-09-27 2022-06-28 安徽工业大学 Low-melting-point alloy phase-change heat dissipation LED automobile headlamp

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