JPH05429A - Manufacture of foam - Google Patents
Manufacture of foamInfo
- Publication number
- JPH05429A JPH05429A JP3151290A JP15129091A JPH05429A JP H05429 A JPH05429 A JP H05429A JP 3151290 A JP3151290 A JP 3151290A JP 15129091 A JP15129091 A JP 15129091A JP H05429 A JPH05429 A JP H05429A
- Authority
- JP
- Japan
- Prior art keywords
- injection molding
- foam
- resin
- injection
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、発泡体の製造方法に関
するものである。詳しくは、低発泡射出成形方法で発泡
体を製造する際に、射出成形機のノズル部に装着された
バルブにより樹脂流路断面積を制御して射出成形するこ
とにより、スキン部の表面が非発泡で、不良凹部（ヒ
ケ）のない外観の優れた、しかもコア部が高発泡倍率の
発泡成形品を得ることができる発泡体の製造方法に関す
るものである。FIELD OF THE INVENTION The present invention relates to a method for producing a foam. Specifically, when a foam is manufactured by the low-foam injection molding method, the surface of the skin part is made non-uniform by controlling the resin flow passage cross-sectional area by a valve mounted on the nozzle part of the injection molding machine to perform injection molding. The present invention relates to a method for producing a foamed product, which is foamed and has an excellent appearance without defective recesses (sinks), and in which a foamed molded product having a core portion with a high expansion ratio can be obtained.
【０００２】[0002]
【従来の技術】従来から、発泡剤を含有する熱可塑性樹
脂（以下、「発泡性樹脂」という。）を射出成形機を用
いて射出成形する発泡体の製造方法において、軽量化や
ヒケ、ソリ等の防止を目的として、発泡剤の添加量を少
なくして射出成形する低発泡射出成形方法が知られてい
る。この場合、成形機の加熱筒温度を発泡剤の分解温度
よりも１０〜２０℃高く設定するため、金型内に発泡性
樹脂を充填、成形すると、成形品の表面には発泡による
スワール模様が発生し外観を非常に悪くする欠点があ
る。また、外観の低下を抑えるために発泡剤の添加量を
減らすと、発泡倍率の高い成形品を得ることができない
欠点がある。そこで、高発泡倍率で外観が良好な成形品
を簡単に得ることができる発泡体の製造方法が要望され
ている。2. Description of the Related Art Conventionally, in a method for producing a foam body in which a thermoplastic resin containing a foaming agent (hereinafter referred to as "foaming resin") is injection-molded by using an injection molding machine, weight reduction, sink marks and warpage are required. For the purpose of preventing such problems, there is known a low foaming injection molding method in which the amount of the foaming agent added is reduced to perform injection molding. In this case, since the heating cylinder temperature of the molding machine is set to 10 to 20 ° C. higher than the decomposition temperature of the foaming agent, when a moldable resin is filled and molded, a swirl pattern due to foaming is formed on the surface of the molded product. There is a drawback that it occurs and makes the appearance very bad. Further, if the amount of the foaming agent added is reduced to suppress the deterioration of the appearance, there is a drawback that a molded product having a high expansion ratio cannot be obtained. Therefore, there is a demand for a method for producing a foamed product, which can easily obtain a molded product having a high expansion ratio and a good appearance.
【０００３】従来、この問題を解決するためにカウンタ
ープレッシャー法（特公昭５１−２７２６６号公報）、
サンドイッチ成形法（特公昭４７−２６１０８号公報）
その他種々の射出成形方法が開発されているが、末だ満
足のできる成形方法は見出されていないのが実情であ
る。すなわち、カウンタープレッシャー法は、先ず、金
型内をガス圧により１０〜２０ｋｇ／ｃｍ2 の圧力に保
ち、それから発泡性樹脂を充填する。この際、発泡剤の
ガス圧は２〜３ｋｇ／ｃｍ2 と低いため、金型内に発泡
性樹脂が充填されるまでは発泡しない。このため発泡性
樹脂が充填された後、ガス圧を抜いて発泡させるので、
この方法では金型のシール性の確保やガス注入装置を設
ける必要があり、簡単な手法とは言えない。Conventionally, in order to solve this problem, a counter pressure method (Japanese Patent Publication No. 51-27266),
Sandwich molding method (Japanese Patent Publication No. 47-26108)
Although various other injection molding methods have been developed, the reality is that no satisfactory molding method has been found. That is, in the counter pressure method, first, the inside of the mold is kept at a pressure of 10 to 20 kg / cm 2 by gas pressure, and then the expandable resin is filled. At this time, since the gas pressure of the foaming agent is as low as 2 to 3 kg / cm 2 , the foaming agent does not foam until the mold is filled with the foamable resin. For this reason, after the foaming resin is filled, the gas pressure is released to cause foaming.
This method cannot be said to be a simple method because it is necessary to secure the sealing property of the mold and provide a gas injection device.
【０００４】また、サンドイッチ成形法は、２系統の射
出ユニットを持つ特殊成形機により、金型内充填初期に
は発泡剤の含まれていない熱可塑性樹脂のユニットで充
填しスキン層を形成させる。その後、連続して発泡性樹
脂のユニットで充填しコア層を形成させる。これによ
り、明確なスキン・コア構造を形成することはできて
も、成形機が特殊になるため、非常に高価になる。[0004] In the sandwich molding method, a special molding machine having two injection units is used to fill the inside of the mold with a thermoplastic resin unit containing no foaming agent to form a skin layer. Thereafter, the core layer is formed by continuously filling with a foamable resin unit. This makes it possible to form a well-defined skin-core structure, but is very expensive because of the special molding machine.
【０００５】その他剪断発熱を利用した射出成形法（特
公昭４６−１３１５１号公報，特公昭５４−２８４２６
号公報）では、成形機のバレル温度を発泡剤の分解温度
以下に設定し、流路断面積の小さなノズルを用いて射出
時の剪断発熱により発泡性樹脂の温度を上昇させる。こ
の際、発泡性樹脂の温度が発泡剤の分解温度以上に上昇
するため、キャビティ内で発泡が起こる。そして、発泡
剤は、分解するまでに若干の遅延時間があるために成形
品の表面では発泡せず、外観の良好な発泡成形品を得る
ことはできる。しかし、一定の流路形状のノズルを用い
るために、剪断発熱は一定になり、表面が非発泡である
発泡体を得ることができないという欠点がある。Other injection molding methods utilizing shear heat generation (Japanese Patent Publication No. 46-13151 and Japanese Patent Publication No. 54-28426).
In Japanese Patent Laid-Open Publication No. 2004-242242, the barrel temperature of the molding machine is set below the decomposition temperature of the foaming agent, and the temperature of the foamable resin is raised by shear heat generation during injection using a nozzle with a small flow passage cross-sectional area. At this time, since the temperature of the foamable resin rises above the decomposition temperature of the foaming agent, foaming occurs in the cavity. The foaming agent does not foam on the surface of the molded product because there is a slight delay before it decomposes, and a foamed molded product having a good appearance can be obtained. However, since the nozzle having a constant flow path shape is used, the shear heat generation becomes constant, and there is a drawback that a foam having a non-foamed surface cannot be obtained.
【０００６】[0006]
【発明が解決しようとする課題】本発明の目的は、スキ
ン部の表面が非発泡で外観が優れ、コア部が高発泡倍率
の発泡成形品を得ることができる低発泡射出成形方法に
よる発泡体の製造方法を提供することである。DISCLOSURE OF THE INVENTION An object of the present invention is to provide a foamed product by a low foaming injection molding method capable of obtaining a foamed molded product having a non-foamed surface of a skin portion and an excellent appearance and a core portion having a high expansion ratio. It is to provide a manufacturing method of.
【０００７】[0007]
【課題を解決するための手段】そこで、本発明者らは、
上述の従来技術の問題点を解決するために種々の検討を
重ねた。その結果、射出成形機のノズル部に装着された
バルブにより樹脂流路断面積を制御して、金型内に発泡
性樹脂を射出することにより問題を解決できることを見
い出した。本発明は、かかる知見に基いて完成したもの
である。Therefore, the present inventors have
Various studies have been repeated in order to solve the above-mentioned problems of the conventional technology. As a result, they have found that the problem can be solved by controlling the resin flow passage cross-sectional area by a valve mounted on the nozzle part of the injection molding machine and injecting the foamable resin into the mold. The present invention has been completed based on such findings.
【０００８】すなわち、本発明は、発泡剤を含有する熱
可塑性樹脂を射出成形機を用いて射出成形する発泡体の
製造方法において、金型内に発泡剤の分解温度以下の温
度で該熱可塑性樹脂を射出し、次いで、該射出成形機の
ノズル部に装着されたバルブにより樹脂流路断面積を制
御して発泡剤の分解温度以上の温度で該熱可塑性樹脂を
該金型内に射出し、成形することを特徴とする発泡体の
製造方法を提供するものである。That is, the present invention relates to a method for producing a foam, in which a thermoplastic resin containing a foaming agent is injection-molded using an injection molding machine, in which the thermoplastic resin is heated in a mold at a temperature not higher than the decomposition temperature of the foaming agent. The resin is injected, and then the resin flow path cross-sectional area is controlled by a valve mounted on the nozzle of the injection molding machine to inject the thermoplastic resin into the mold at a temperature equal to or higher than the decomposition temperature of the foaming agent. The present invention provides a method for producing a foam, which comprises molding.
【０００９】本発明の発泡体の製造方法においては、使
用する射出成形機に大きな特徴がある。すなわち、射出
成形機には、ノズル部に樹脂流量を制御することのでき
る流路断面積調整用バルブ（以下、「バルブ」とい
う。）が装着されている。In the method for producing a foam of the present invention, the injection molding machine used has a great feature. That is, the injection molding machine is equipped with a valve for controlling the flow passage cross-sectional area (hereinafter, referred to as “valve”) capable of controlling the resin flow rate at the nozzle portion.
【００１０】この射出成形機を用いて射出成形する本発
明の発泡体の製造方法について図面を参照しながら説明
する。図１は、本発明において使用される射出成形機１
のノズル３に装着されたバルブ５が全開した時のノズル
部の模式断面図である。ここで、射出成形機１には、発
泡性樹脂ａ（図３〜８参照）が装填され、熱可塑化され
た熱可塑性樹脂が一時滞留するための加熱筒２が設けら
れている。そして、射出成形機１には、その熱可塑化さ
れた発泡性樹脂ａを金型６に射出成形するための樹脂流
路４が形成されたノズル３が付設されている。本発明に
おいては、このノズル３に樹脂流路４の断面積を制御す
るためのバルブ５が装着されている。図２は、射出過程
中にバルブ５により樹脂流路４の断面積を制御したとき
のノズル部の模式断面図である。本発明の発泡体の製造
方法においては、バルブ５を全開しスキン層を形成する
だけの発泡性樹脂ａを加熱筒２から金型６（図３〜８参
照）に射出した後、バルブ５で樹脂流路４の断面積を制
御しコア部形成に必要なだけの発泡性樹脂ａを射出し、
成形する。A method for producing a foam according to the present invention, which is injection-molded using this injection molding machine, will be described with reference to the drawings. FIG. 1 shows an injection molding machine 1 used in the present invention.
FIG. 6 is a schematic cross-sectional view of the nozzle portion when the valve 5 attached to the nozzle 3 is fully opened. Here, the injection molding machine 1 is provided with a foaming resin a (see FIGS. 3 to 8) and is provided with a heating cylinder 2 for temporarily retaining the thermoplasticized thermoplastic resin. Further, the injection molding machine 1 is provided with a nozzle 3 in which a resin flow path 4 for injection-molding the thermoplastic resin foamable resin a is formed. In the present invention, the nozzle 3 is equipped with a valve 5 for controlling the cross-sectional area of the resin flow path 4. FIG. 2 is a schematic cross-sectional view of the nozzle portion when the cross-sectional area of the resin flow path 4 is controlled by the valve 5 during the injection process. In the method for producing a foam according to the present invention, after the valve 5 is fully opened and the foamable resin a for forming the skin layer is injected from the heating cylinder 2 into the mold 6 (see FIGS. 3 to 8), the valve 5 is used. By controlling the cross-sectional area of the resin flow path 4 and injecting the expandable resin a required for forming the core portion,
Mold.
【００１１】このような特徴を有する射出成形機を用い
る本発明の発泡体の製造方法について、更に、図面を参
照しながら説明する。図３〜図８は、本発明の発泡体の
製造方法を実施する際の射出成形プロセスの説明図であ
る。先ず、図３は、発泡性樹脂ａが、加熱筒２において
熱可塑化されて射出される迄のブロセスの一部説明図で
ある。先ず、ノズル３に装着されたバルブ５は、開度０
％の全閉状態にし、射出成形機１の加熱筒２に発泡性樹
脂ａが装填される。ここで、発泡性樹脂ａは、添加され
ている発泡剤の分解温度よりも10〜20℃低く設定されて
いる温度で加熱され、熱可塑化される。加熱筒２におい
て熱可塑化された発泡性樹脂ａは、図４に示す射出初期
にバルブ５の開度１００％で、発泡体のスキン部を形成
するのに必要な量だけ樹脂流路４を通じて金型６に射出
充填される。金型６に発泡体のスキン層を形成するだけ
の発泡性樹脂量が充填された後、図５に示すようにバル
ブ５の開度を流路断面積の５〜６０％に制御し、続いて
コア部を形成するために必要なだけ熱可塑化された発泡
性樹脂ａを金型６に射出充填する。ここで、発泡性樹脂
ａは、バルブ５により樹脂流路４の断面積が制御された
状態でノズル３を通過する際、大きな剪断力を受けて発
熱し高温化される（図６のｂ参照）。本発明者らの実験
によると、２００℃前後で射出された発泡性樹脂につい
て、バルブの開度が３０％に樹脂流路を制御したときの
樹脂温度を測定した結果では、２５０〜２６０℃と発泡
剤が発泡するのに充分な温度に高温化されているデータ
を得ている。金型６にコア部を形成するだけの発泡性樹
脂が射出充填された後、図７に示すようにバルブ５の開
度を０％に全閉状態にし、発泡性樹脂中に含まれる発泡
剤が発泡するに足る時間暫時放置される。ここで、発泡
性樹脂中に含まれる発泡剤が剪断力による高温化により
発泡し、表面部が非発泡で、コア部に高発泡樹脂層を形
成し射出成形は完了する（図８参照）。そして、発泡成
形後は、金型内で成形品を冷却してから、金型６を開い
て成形品を取り出すことにより、本発明による発泡成形
品を得ることができる。The method for producing a foam of the present invention using the injection molding machine having the above characteristics will be further described with reference to the drawings. 3 to 8 are explanatory views of an injection molding process when carrying out the method for producing a foam of the present invention. First, FIG. 3 is a partial explanatory view of the process until the foamable resin a is thermoplasticized in the heating cylinder 2 and injected. First, the valve 5 attached to the nozzle 3 has an opening of 0.
%, And the foaming resin a is loaded into the heating cylinder 2 of the injection molding machine 1. Here, the foamable resin a is heated at a temperature which is set to be 10 to 20 ° C. lower than the decomposition temperature of the added foaming agent to be plasticized. The expandable resin a that has been plasticized in the heating cylinder 2 passes through the resin flow path 4 in an amount required to form the skin portion of the foam with the opening of the valve 5 being 100% at the initial stage of injection shown in FIG. The mold 6 is injected and filled. After the mold 6 is filled with the amount of the foamable resin for forming the skin layer of the foam, the opening degree of the valve 5 is controlled to 5 to 60% of the flow passage cross-sectional area as shown in FIG. The mold 6 is injection-filled with the foamable resin a which is thermoplasticized as much as necessary to form the core part. Here, when the foamable resin a passes through the nozzle 3 in a state where the cross-sectional area of the resin flow path 4 is controlled by the valve 5, the foamable resin a receives a large shearing force to generate heat and become high in temperature (see b in FIG. 6). ). According to the experiments conducted by the present inventors, with respect to the foamable resin injected at around 200 ° C., the result of measuring the resin temperature when the resin flow path was controlled so that the valve opening degree was 30% was 250 to 260 ° C. We have obtained data that the blowing agent has been heated to a temperature sufficient for foaming. After the foaming resin for forming the core portion is injected and filled into the mold 6, the valve 5 is fully closed to 0% as shown in FIG. 7, and the foaming agent contained in the foaming resin is included. It is left for a while until it foams. Here, the foaming agent contained in the foamable resin is foamed by the high temperature caused by the shearing force, the surface portion is non-foamed, the highly foamed resin layer is formed in the core portion, and the injection molding is completed (see FIG. 8). After foam molding, the molded product is cooled in the mold, and then the mold 6 is opened to take out the molded product, whereby the foam molded product according to the present invention can be obtained.
【００１２】なお、本発明において、発泡性樹脂を構成
する熱可塑性樹脂としては、発泡射出成形し得る熱可塑
性樹脂のすべてを用いることができる。例えば、ポリエ
チレン，ポリブロビレン，ポリスチレン，ＡＢＳ樹脂，
ポリカーボネート，ナイロン等が挙げられる。また、発
泡剤としては、通常の発泡射出成形法において適用され
ている有機，無機の化学的発泡剤を用いることができ
る。例えば、アゾジカルボンアミド，Ｎ−Ｎ’ジニトロ
ソペンタメチレンテトラミン，ｐｐ’ビス（ベンゼンス
ルホニルヒドラジド）エーテル，ｐトルエンスルホニル
ヒドラジド，重曹，重炭酸アンモニア等が挙げられる。
これらの発泡剤の熱可塑性樹脂に対する添加率は、熱可
塑性樹脂、発泡剤の種類あるいは所望する発泡度等によ
って異なるが、0.１〜5.０重量％の範囲が好ましい。そ
の他、必要に応じて着色剤，滑剤その他助剤等を用いる
こともできる。そして、これら熱可塑性樹脂，発泡剤そ
の他助剤等は、通常使用されている混合攪拌機で予め充
分に混合攪拌されてから加熱筒に送られる。In the present invention, as the thermoplastic resin constituting the foamable resin, all thermoplastic resins which can be foamed and injection molded can be used. For example, polyethylene, polybrobylene, polystyrene, ABS resin,
Examples include polycarbonate and nylon. Further, as the foaming agent, an organic or inorganic chemical foaming agent applied in a general foaming injection molding method can be used. For example, azodicarbonamide, NN ′ dinitrosopentamethylenetetramine, pp ′ bis (benzenesulfonylhydrazide) ether, ptoluenesulfonylhydrazide, sodium bicarbonate, ammonium bicarbonate and the like can be mentioned.
The addition ratio of these foaming agents to the thermoplastic resin varies depending on the types of the thermoplastic resin and the foaming agent, the desired foaming degree, etc., but is preferably in the range of 0.1 to 5.0% by weight. In addition, colorants, lubricants and other auxiliaries can be used if necessary. Then, the thermoplastic resin, the foaming agent and other auxiliaries are thoroughly mixed and stirred in advance by a commonly used mixing stirrer and then sent to the heating cylinder.
【００１３】[0013]
【実施例】さらに、本発明を実施例および比較例により
詳しく説明するが、本発明は、これらの実施例によって
限定されるものではない。The present invention will be further described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
【００１４】実施例１
ポリプロピレン（出光石油化学（株）製，商品名：出光
ポリプロＪ−４５０Ｈ）を用いて、発泡温度２３０℃の
炭酸ガス系の発泡剤（永和化成工業（株）製，商品名：
ポリスレン ＥＥ−２０７）を１重量部添加して混合攪
拌し、発泡性樹脂を調製した。この発泡性樹脂を、ノズ
ルの流路断面積が調整可能な射出成形機（スクリュー径
４５ｍｍ，型締力１５０ｔ）を用いて射出成形した。本
成形機はノズルの流路直径が３０ｍｍ（断面積7.１ｃｍ
2 ) で、バルブにより開度を０〜１００％制御すること
ができる。使用した金型は成形品形状が基本肉厚４ｍ
ｍ，縦４００ｍｍ，横１００ｍｍであり末端部にボスが
配置されている。射出成形条件は以下の通りである。
成形温度 ２００℃
金型温度 ４０℃
射出時間 ３秒，射出圧力 ８０ｋｇ／ｃｍ2 （ゲー
ジ圧）
ノズル部のバブル開度 開度
可塑化〜射出開始 ０％
射出開始〜射出1.５秒後 １００％
射出1.５秒〜射出完了時（３秒後） ３０％
射出完了〜可塑化 ０％
このときのバルブ部通過後の樹脂温度を赤外線温度計に
より測定した結果、バルブ開度が１００％の時の最高温
度は２１８℃で、また、バルブ開度が３０％の時の最高
温度は２５６℃であった。発泡倍率，外観，ヒケ，ソリ
の評価結果を以下に示す。発泡倍率（発泡剤無添加の
成形品重量／発泡成形品の重量）は1.１であった。表
面外観の評価として光沢度を測定した結果、グロスは５
８であった。ボス部表面のヒケを表面粗さ計により測
定した結果、最大深さは４μｍであった。ソリの評価
として、成形品の３ケ所の角が平面上に乗るように配置
し、残りの角がその表面に対してどれだけの距離がある
かを三次元測定機で測定した結果、ソリ量は2.５ｍｍで
あった。Example 1 Polypropylene (manufactured by Idemitsu Petrochemical Co., Ltd., trade name: Idemitsu Polypro J-450H) was used, and a carbon dioxide-based foaming agent having a foaming temperature of 230 ° C. (manufactured by Eiwa Chemical Industry Co., Ltd.) Name:
1 part by weight of Polythrene EE-207) was added and mixed with stirring to prepare a foamable resin. This foamable resin was injection molded using an injection molding machine (screw diameter 45 mm, mold clamping force 150 t) in which the flow passage cross-sectional area of the nozzle could be adjusted. This molding machine has a nozzle flow path diameter of 30 mm (cross-sectional area 7.1 cm
In 2 ), the opening can be controlled by a valve by 0 to 100%. The mold used has a basic wall thickness of 4 m.
The length is m, the length is 400 mm, and the width is 100 mm, and a boss is arranged at the end. The injection molding conditions are as follows. Molding temperature 200 ℃ Mold temperature 40 ℃ Injection time 3 seconds, Injection pressure 80 kg / cm 2 (gauge pressure) Bubble opening of nozzle part Opening degree Plasticization-injection start 0% Injection start-injection 1.5 seconds after 100% Injection 1.5 seconds-When injection is completed (after 3 seconds) 30% Injection completion-Plasticization 0% At this time, when the valve opening is 100% as a result of measuring the resin temperature after passing through the valve section with an infrared thermometer. Had a maximum temperature of 218 ° C, and the maximum temperature at a valve opening of 30% was 256 ° C. The evaluation results of expansion ratio, appearance, sink mark, and warp are shown below. The expansion ratio (the weight of the molded product containing no foaming agent / the weight of the foamed molded product) was 1.1. As a result of measuring the glossiness as an evaluation of the surface appearance, the gloss is 5
It was 8. As a result of measuring the sink marks on the surface of the boss portion with a surface roughness meter, the maximum depth was 4 μm. As an evaluation of the warpage, the three corners of the molded product were placed so that they would lie on a plane, and the distance between the remaining corners and the surface was measured with a coordinate measuring machine. Was 2.5 mm.
【００１５】比較例１
実施例１の発泡性樹脂を用い、同じ成形機で、ノズル部
のバルブ開度を常時１００％にして射出成形した。しか
し、成形温度は、ポリプロピレンを用いて発泡成形する
時に通常採用されている温度を採用した。射出成形条件
は以下の通りである。
成形温度 ２４０℃
金型温度 ４０℃
射出時間 ２秒，射出圧力 ９０ｋｇ／ｃｍ2 （ゲー
ジ圧）
ノズル部のバルブ開度 常時１００％
実施例１と同様にして外観，ヒケ，ソリを評価した結果
を以下に示す。発泡倍率は実施例１と同様に1.１であ
った。表面外観の測定として光沢度を測定した結果、
グロスは３８であった。ボス部裏面のヒケの最大深さ
は８μｍであった。実施例１と同様にソリの評価を行
った結果、ソリ量は2.７ｍｍであった。上記の実施例１
及び比較例１の結果より、実施例１によれば発泡剤無添
加の材料と同程度の表面外観を維持しながら発泡倍率が
高く、ソリ，ヒケの少ない成形品を得ることができた。Comparative Example 1 Using the foamable resin of Example 1, injection molding was carried out with the same molding machine, with the valve opening of the nozzle section always set to 100%. However, as the molding temperature, a temperature that is usually adopted when performing foam molding using polypropylene is adopted. The injection molding conditions are as follows. Molding temperature 240 ° C. Mold temperature 40 ° C. Injection time 2 seconds, Injection pressure 90 kg / cm 2 (gauge pressure) Valve opening of nozzle 100% at all times The results of evaluation of appearance, sink marks, and warpage were made in the same manner as in Example 1. It is shown below. The expansion ratio was 1.1 as in Example 1. As a result of measuring the glossiness as a measurement of the surface appearance,
The gross was 38. The maximum depth of the sink marks on the back surface of the boss portion was 8 μm. The warpage was evaluated in the same manner as in Example 1, and as a result, the warpage amount was 2.7 mm. Example 1 above
Further, from the results of Comparative Example 1, according to Example 1, it was possible to obtain a molded product having a high expansion ratio while maintaining the same surface appearance as the material without the addition of the foaming agent, and having less warpage and sink marks.
【００１６】実施例２
ポリスチレン（出光石油化学（株）製，出光スチロール
ＨＴ５１）を用いて、発泡温度２３０℃のアゾジカル
ボンアミド系の発泡剤を0.７重量部添加して混合攪拌
し、発泡性樹脂を調製した。この発泡性樹脂を、実施例
１と同じ成形機で射出成形した。使用した金型は成形品
形状が基本肉厚さ４ｍｍ，縦４００ｍｍ，横１００ｍｍ
であり成形品の縦方向に高さ１０ｍｍ，幅1.５ｍｍのリ
ブがある。射出成形条件は以下の通りである。
成形温度 ２０５℃
金型温度 ４０℃
射出時間 ３秒，射出圧力 ９０ｋｇ／ｃｍ2 （ゲー
ジ圧）
ノズル部のバブル開度 開度
可塑化〜射出開始 ０％
射出開始〜射出1.５秒後 １００％
射出1.５秒〜射出完了時（３秒後） ３０％
射出完了〜可塑化 ０％
このときのバルブ部通過後の樹脂温度を赤外線温度計に
より測定した結果、バルブ開度が１００％の時の最高温
度は２２３℃で、また、バルブ開度が３０％の時の最高
温度は２６２℃であった。実施例１と同様にして発泡倍
率，外観，ヒケを評価した結果を以下に示す。発泡倍
率（発泡剤無添加の成形品重量／発泡成形品の重量）は
1.０８であった。表面外観の評価として光沢度を測定
した結果、グロスは５６であった。リブ部裏面のヒケ
の最大深さは４μｍであった。Example 2 Using polystyrene (Idemitsu Styrol HT51, manufactured by Idemitsu Petrochemical Co., Ltd.), 0.7 part by weight of an azodicarbonamide type foaming agent having a foaming temperature of 230 ° C. was added, mixed and stirred to foam. A resin was prepared. This foamable resin was injection molded with the same molding machine as in Example 1. The mold used has a molded product with a basic thickness of 4 mm, length 400 mm, width 100 mm.
There is a rib with a height of 10 mm and a width of 1.5 mm in the vertical direction of the molded product. The injection molding conditions are as follows. Molding temperature 205 ° C Mold temperature 40 ° C Injection time 3 seconds, Injection pressure 90kg / cm 2 (gauge pressure) Nozzle bubble opening degree Opening plasticization-injection start 0% Injection start-injection 1.5 seconds later 100% Injection 1.5 seconds-When injection is completed (after 3 seconds) 30% Injection completion-Plasticization 0% At this time, when the valve opening is 100% as a result of measuring the resin temperature after passing through the valve section with an infrared thermometer. Had a maximum temperature of 223 ° C, and the maximum temperature at a valve opening of 30% was 262 ° C. The results of evaluation of foaming ratio, appearance and sink mark in the same manner as in Example 1 are shown below. Foaming ratio (weight of molded product without foaming agent / weight of foamed molded product)
It was 1.08. As a result of measuring the glossiness as an evaluation of the surface appearance, the gloss was 56. The maximum depth of the sink mark on the back surface of the rib portion was 4 μm.
【００１７】比較例２
実施例２の発泡性樹脂を用い、同じ成形機で、ノズル部
のバルブ開度を常時１００％にして射出成形した。しか
し、成形温度は、ポリスチレンを用いて発泡成形する時
に通常採用されている温度を採用した。射出成形条件は
以下の通りである。
成形温度 ２４０℃
金型温度 ４０℃
射出時間 ２秒，射出圧力 １１０ｋｇ／ｃｍ2 （ゲ
ージ圧）
ノズル部のバルブ開度 常時１００％
実施例１と同様にして発泡倍率，外観，ヒケを評価した
結果を以下に示す。発泡倍率は実施例２と同様に1.０
８であった。表面外観の測定として光沢度を測定した
結果、グロスは３２であった。リブ部裏面のヒケの最
大深さは５μｍであった。上記の実施例２及び比較例２
の結果より、実施例２によればポリスチレンにおいても
外観が良好で、ヒケの少ない成形品を得ることができ
た。Comparative Example 2 Using the foamable resin of Example 2, injection molding was carried out with the same molding machine, with the valve opening of the nozzle section always set to 100%. However, as the molding temperature, a temperature that is usually adopted when performing foam molding using polystyrene is adopted. The injection molding conditions are as follows. Molding temperature 240 ° C. Mold temperature 40 ° C. Injection time 2 seconds, Injection pressure 110 kg / cm 2 (gauge pressure) Valve opening of nozzle 100% at all times Results of evaluation of foaming ratio, appearance and sink mark as in Example 1 Is shown below. The expansion ratio was 1.0 as in Example 2.
It was 8. As a result of measuring the glossiness as a measurement of the surface appearance, the gloss was 32. The maximum depth of the sink mark on the back surface of the rib portion was 5 μm. Example 2 and Comparative Example 2 described above
From the results, according to Example 2, it was possible to obtain a molded product having a good appearance even with polystyrene and having less sink marks.
【００１８】[0018]
【発明の効果】本発明によると、表面のヒケが少なく、
しかもコア部を高発泡させることができ、製品の軽量化
に効果的であると同時に外観の優れた発泡成形品を得る
ことができる。その工業的利用価値は、極めて大なるも
のがある。According to the present invention, the number of sink marks on the surface is small,
Moreover, the core portion can be highly foamed, which is effective in reducing the weight of the product, and at the same time, a foamed molded product having an excellent appearance can be obtained. Its industrial utility value is extremely high.
【図１】射出成形機のノズル部に装着されたバルブの開
度が１００％の時のノズル部の模式断面図である。FIG. 1 is a schematic cross-sectional view of a nozzle portion when a valve mounted on the nozzle portion of an injection molding machine has an opening of 100%.
【図２】射出成形機の樹脂流路断面積をバルブにより制
御した時のノズル部の模式断面図である。FIG. 2 is a schematic cross-sectional view of a nozzle portion when a resin flow passage cross-sectional area of an injection molding machine is controlled by a valve.
【図３】本発明の発泡体の製造方法の射出成形プロセス
の一部説明図である。FIG. 3 is a partial explanatory view of the injection molding process of the foam manufacturing method of the present invention.
【図４】本発明の発泡体の製造方法の射出成形プロセス
の一部説明図である。FIG. 4 is a partial explanatory view of the injection molding process of the foam manufacturing method of the present invention.
【図５】本発明の発泡体の製造方法の射出成形プロセス
の一部説明図である。FIG. 5 is a partial explanatory view of the injection molding process of the method for producing a foam of the present invention.
【図６】本発明の発泡体の製造方法の射出成形プロセス
の一部説明図である。FIG. 6 is a partial explanatory view of an injection molding process of the foam manufacturing method of the present invention.
【図７】本発明の発泡体の製造方法の射出成形プロセス
の一部説明図である。FIG. 7 is a partial explanatory view of the injection molding process of the foam manufacturing method of the present invention.
【図８】本発明の発泡体の製造方法の射出成形プロセス
の一部説明図である。FIG. 8 is a partial explanatory view of an injection molding process of the foam manufacturing method of the present invention.
１：射出成形機 ２：加熱筒 ３：ノズル ４：樹脂流路 ５：バルブ ６：金型 ａ：発泡性樹脂 ｂ：高温樹脂 ｃ：高発泡樹脂層 1: Injection molding machine 2: Heating cylinder 3: Nozzle 4: Resin flow path 5: valve 6: Mold a: Foaming resin b: High temperature resin c: Highly foamed resin layer
Claims (3)
形機を用いて射出成形する発泡体の製造方法において、
金型内に発泡剤の分解温度以下の温度で該熱可塑性樹脂
を射出し、次いで、該射出成形機のノズル部に装着され
た流路断面積調整用バルブにより流路断面積を制御して
発泡剤の分解温度以上の温度で該熱可塑性樹脂を該金型
内に射出し、成形することを特徴とする発泡体の製造方
法。1. A method for producing a foam, which comprises subjecting a thermoplastic resin containing a foaming agent to injection molding using an injection molding machine,
The thermoplastic resin is injected into the mold at a temperature not higher than the decomposition temperature of the foaming agent, and then the flow passage cross-sectional area is controlled by a flow passage cross-sectional area adjusting valve mounted on the nozzle of the injection molding machine. A method for producing a foam, comprising injecting the thermoplastic resin into the mold at a temperature equal to or higher than the decomposition temperature of the foaming agent to mold the foam.
％に制御する請求項１の発泡体の製造方法。2. The opening of the resin flow path of the injection molding machine is 5 to 60.
The method for producing a foam according to claim 1, wherein the content is controlled to be%.
製造方法。3. The method for producing a foam according to claim 1, wherein the surface is non-foamed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3151290A JPH05429A (en) | 1991-06-24 | 1991-06-24 | Manufacture of foam |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3151290A JPH05429A (en) | 1991-06-24 | 1991-06-24 | Manufacture of foam |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05429A true JPH05429A (en) | 1993-01-08 |
Family
ID=15515453
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3151290A Pending JPH05429A (en) | 1991-06-24 | 1991-06-24 | Manufacture of foam |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05429A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL1004572C2 (en) * | 1996-11-20 | 1998-05-25 | Corell Resin Technology Bv | A method for manufacturing a monolithic plastic object, as well as an object obtained by said method. |
| EP1075933A2 (en) * | 1999-08-09 | 2001-02-14 | Jsp Corporation | Multi-layer expansion-molded article of polypropylene resin, production process thereof, and container, shock-absorbing material for automobile and automotive member formed of the multi-layer expansion-molded article of polypropylene resin |
| WO2003072335A1 (en) * | 2002-02-28 | 2003-09-04 | Ube Machinery Corporation, Ltd. | Method for expansion injection molding |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5814725A (en) * | 1981-07-17 | 1983-01-27 | Kobe Steel Ltd | Method and apparatus for foam injection molding |
| JPS60242022A (en) * | 1984-05-10 | 1985-12-02 | Mitsubishi Heavy Ind Ltd | Injection device |
| JPS63182126A (en) * | 1987-01-23 | 1988-07-27 | Komatsu Ltd | Control method of molding of injection molding machine |
-
1991
- 1991-06-24 JP JP3151290A patent/JPH05429A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5814725A (en) * | 1981-07-17 | 1983-01-27 | Kobe Steel Ltd | Method and apparatus for foam injection molding |
| JPS60242022A (en) * | 1984-05-10 | 1985-12-02 | Mitsubishi Heavy Ind Ltd | Injection device |
| JPS63182126A (en) * | 1987-01-23 | 1988-07-27 | Komatsu Ltd | Control method of molding of injection molding machine |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL1004572C2 (en) * | 1996-11-20 | 1998-05-25 | Corell Resin Technology Bv | A method for manufacturing a monolithic plastic object, as well as an object obtained by said method. |
| WO1998022272A1 (en) * | 1996-11-20 | 1998-05-28 | Corell Resin Technology B.V. | Method for manufacturing a monolithic plastic object, and an object obtained with this method |
| EP1075933A2 (en) * | 1999-08-09 | 2001-02-14 | Jsp Corporation | Multi-layer expansion-molded article of polypropylene resin, production process thereof, and container, shock-absorbing material for automobile and automotive member formed of the multi-layer expansion-molded article of polypropylene resin |
| EP1075933A3 (en) * | 1999-08-09 | 2001-12-12 | Jsp Corporation | Multi-layer expansion-molded article of polypropylene resin, production process thereof, and container, shock-absorbing material for automobile and automotive member formed of the multi-layer expansion-molded article of polypropylene resin |
| US6875484B1 (en) | 1999-08-09 | 2005-04-05 | Jsp Corporation | Multi-layer expansion-molded article of polypropylene resin, production process thereof, and container, shock-absorbing material for automobile and automotive member formed of the multi-layer expansion-molded article of polypropylene resin |
| WO2003072335A1 (en) * | 2002-02-28 | 2003-09-04 | Ube Machinery Corporation, Ltd. | Method for expansion injection molding |
| KR100919690B1 (en) * | 2002-02-28 | 2009-10-01 | 우베 고산 기카이 가부시키가이샤 | Method for expansion injection molding |
| US7704423B2 (en) | 2002-02-28 | 2010-04-27 | Ube Machinery Corporation, Ltd. | Method for expansion injection molding |
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