JPH0780883A - Blow injection molded part and method thereof - Google Patents
Blow injection molded part and method thereofInfo
- Publication number
- JPH0780883A JPH0780883A JP25093593A JP25093593A JPH0780883A JP H0780883 A JPH0780883 A JP H0780883A JP 25093593 A JP25093593 A JP 25093593A JP 25093593 A JP25093593 A JP 25093593A JP H0780883 A JPH0780883 A JP H0780883A
- Authority
- JP
- Japan
- Prior art keywords
- hollow
- different surface
- mold cavity
- different
- hollow portion
- 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.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/1703—Introducing an auxiliary fluid into the mould
- B29C45/1704—Introducing an auxiliary fluid into the mould the fluid being introduced into the interior of the injected material which is still in a molten state, e.g. for producing hollow articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/37—Mould cavity walls, i.e. the inner surface forming the mould cavity, e.g. linings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/1703—Introducing an auxiliary fluid into the mould
- B29C45/1704—Introducing an auxiliary fluid into the mould the fluid being introduced into the interior of the injected material which is still in a molten state, e.g. for producing hollow articles
- B29C2045/1717—Temperature controlled mould parts to control the location or configuration of the hollow
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、金型キャビティ内に射
出した溶融樹脂中に加圧流体を圧入し、必要な冷却後に
この加圧流体を排出することで形成された中空部を有す
る中空射出成形品及びその中空射出成形方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow structure having a hollow portion formed by pressurizing a pressurized fluid into a molten resin injected into a mold cavity and discharging the pressurized fluid after cooling as necessary. The present invention relates to an injection molded product and a hollow injection molding method thereof.
【０００２】[0002]
【従来の技術】従来、金型キャビティに、金型キャビテ
ィを満たすに足りない量の溶融樹脂を射出した後、加圧
ガスを圧入して中空部を形成する中空射出成形方法にお
いて、金型キャビティ内の樹脂に温度差を持たせ、高温
の溶融樹脂部に優先的に加圧ガスが入り込むことを利用
して、不均一に広がる中空部を有する中空射出成形品と
することが知られている（特公昭６１−５３２０８号公
報）。この技術においては、金型キャビティ内の溶融樹
脂に温度差を持たせることを、金型キャビティ面を部分
的に冷却又は加熱することで行っている。2. Description of the Related Art Conventionally, in a hollow injection molding method in which a hollow portion is formed by injecting a pressurized gas into a mold cavity after injecting an amount of molten resin insufficient to fill the mold cavity, It is known that a hollow injection-molded article having a hollow portion that spreads non-uniformly is obtained by giving a temperature difference to the resin inside and preferentially introducing pressurized gas into the high temperature molten resin portion. (Japanese Patent Publication No. 61-53208). In this technique, the molten resin in the mold cavity is provided with a temperature difference by partially cooling or heating the mold cavity surface.
【０００３】また、所定位置に補強用のリブ部を有する
射出成形品の成形に際し、金型キャビティに溶融樹脂を
射出した後加圧ガスを圧入し、加圧ガスが厚肉部に優先
的に圧入されることを利用して、リブ部に沿って中空部
を形成した中空射出成形品とすることも知られている
（特開昭６３−２６８６１１号公報）。Further, when molding an injection-molded article having a reinforcing rib portion at a predetermined position, a molten resin is injected into a mold cavity and then pressurized gas is injected, so that the pressurized gas is preferentially applied to a thick portion. It is also known to make a hollow injection molded product in which a hollow portion is formed along the rib portion by utilizing press fitting (Japanese Patent Laid-Open No. 63-268611).
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記特
公昭６１−５３２０８号公報に記載された従来の技術に
は次のような問題がある。However, the conventional technique disclosed in Japanese Patent Publication No. 61-53208 has the following problems.
【０００５】（１）金型キャビティ面を部分的に冷却又
は加熱するのは、特別な冷却または加熱手段を備えた金
型を用意しなければならず、設備的負担が大きい問題が
ある。(1) To partially cool or heat the mold cavity surface, it is necessary to prepare a mold provided with a special cooling or heating means, which causes a problem of a large facility load.
【０００６】（２）部分的に冷却又は加熱するといって
も、一定位置に一定の温度差を付けることは困難で、温
度差を付ける領域が不特定となる。従って、当然形成さ
れる中空部は不均一に広がるものとなるが、板状成形品
にこのような不均一に広がる中空部を形成すると、そり
を生じる原因となる。(2) Even if partial cooling or heating is performed, it is difficult to make a constant temperature difference at a fixed position, and the region where the temperature difference is made becomes unspecified. Therefore, the formed hollow portion naturally spreads unevenly. However, when such a hollow portion spreads unevenly in the plate-shaped molded article, it causes warpage.
【０００７】（３）不均一に広がる中空部では、偏った
大きさの中空部となりやすく、１箇所に大きな中空部が
形成された場合、強度不足を生じる原因となる。(3) In the hollow portion which spreads unevenly, a hollow portion having an uneven size is apt to be formed, and when a large hollow portion is formed at one place, insufficient strength is caused.
【０００８】また、上記特開昭６３−２６８６１１号公
報に記載された従来の技術には次のような問題がある。Further, the conventional technique described in the above-mentioned Japanese Patent Laid-Open No. 63-268611 has the following problems.
【０００９】（１）リブ部は凸部として形成されるの
で、その形成位置が制限される結果、中空部を形成する
位置も制約を受ける。(1) Since the rib portion is formed as a convex portion, its forming position is limited, and as a result, the position where the hollow portion is formed is also restricted.
【００１０】（２）リブ部を目に付かない裏面や内面側
に配置することで外観の低下を防いでいるが、表面側の
リブ部に対応する位置に若干のヒケや艶むらを生じ、こ
れが外観の低下をもたらす。(2) The appearance of the rib is prevented from being deteriorated by arranging the rib portion on the back surface or the inner surface side, which is inconspicuous, but a slight sink mark or uneven gloss is generated at the position corresponding to the rib portion on the front surface side. This results in a poor appearance.
【００１１】本発明は、このような従来の問題点に鑑み
てなされたもので、簡便な金型によって、表面状態を低
下させることなく、中空部の形成箇所を任意に制御でき
るようにすることを目的とする。The present invention has been made in view of the above conventional problems, and it is possible to arbitrarily control the formation location of the hollow portion by a simple mold without deteriorating the surface condition. With the goal.
【００１２】[0012]
【課題を解決するための手段及び作用】このために請求
項１の発明では、図１及び図２に示されるように、表面
の予め設定した位置が、その他の表面を成形した金型キ
ャビティ表面とは熱伝導率が相違する金型キャビティ表
面によって成形された異表面１となっており、この異表
面に対応して中空部２が形成されている中空射出成形品
としているものである。For this reason, in the invention of claim 1, as shown in FIGS. 1 and 2, the preset position of the surface is the surface of the mold cavity where the other surface is molded. Means a different surface 1 formed by mold cavity surfaces having different thermal conductivities, and a hollow injection molded product in which a hollow portion 2 is formed corresponding to the different surface.
【００１３】また、請求項２の発明では、図１及び図８
に示されるように、所定の中空部２の形成位置に対応す
る金型キャビティ表面が、その他の金型キャビティ表面
より熱伝導率の低い材料で構成された金型を用いる中空
射出成方法としているものである。Further, according to the invention of claim 2, FIG. 1 and FIG.
As shown in FIG. 3, a hollow injection molding method is used in which a mold cavity surface corresponding to a predetermined hollow portion 2 forming position is made of a material having a lower thermal conductivity than other mold cavity surfaces. It is a thing.
【００１４】更に請求項３の発明では、やはり図１及び
図８に示されるように、所定の中空部２の形成位置に対
応する位置以外の金型キャビティ表面が、所定の中空部
の形成位置に対応する金型キャビティ表面より熱伝導率
の高い材料で構成された金型を用いる中空射出成形方法
としているものである。Further, in the third aspect of the invention, as shown in FIGS. 1 and 8, the mold cavity surface other than the position corresponding to the position where the predetermined hollow part 2 is formed is the position where the predetermined hollow part is formed. The hollow injection molding method uses a mold made of a material having a higher thermal conductivity than the surface of the mold cavity corresponding to.
【００１５】更に本発明を説明する。The present invention will be further described.
【００１６】図１及び図２に示されるように、請求項１
の発明に係る中空射出成形品は、表面の予め予定した位
置に異表面１を有し、しかもこの異表面１に対応して中
空部２が形成されているものである。As shown in FIG. 1 and FIG.
The hollow injection-molded article according to the invention has the different surface 1 at a predetermined position on the surface, and the hollow portion 2 is formed corresponding to the different surface 1.
【００１７】上記異表面１は、この異表面１部分を成形
した金型キャビティ表面が、他の表面を成形した金型キ
ャビティ表面と熱伝導率が相違する材料で構成されてい
ることによって形成されるものである。The different surface 1 is formed by forming the surface of the mold cavity in which the portion of the different surface 1 is formed from a material having a different thermal conductivity from the surface of the mold cavity in which the other surface is formed. It is something.
【００１８】この異表面１は、例えば他の表面と光沢が
相違すること、異表面１全体がその周囲よりやや凸又は
凹部となっていること、異表面１の輪郭を形成する筋状
の凸又は凹部が形成されていること等によって他の表面
と区別することができる。The different surface 1 has, for example, a gloss different from that of the other surface, that the entire different surface 1 is slightly convex or concave than its surroundings, and a streak-like convex forming the contour of the different surface 1. Alternatively, it can be distinguished from other surfaces by the fact that the recesses are formed.
【００１９】更に具体的には、異表面１は、予め設定さ
れた当該部分を成形する金型キャビティ表面位置に、他
の金型キャビティ表面とは熱伝導率の異なる材料を埋め
込んで成形を行うことで形成されるものである。従っ
て、冷却状態が他の表面部分とは相違して来ることか
ら、光沢の相違を生じる場合がある。また、熱伝導率の
相違する材料の埋め込み状態によって、異表面１が凸又
は凹部となったり、異表面１の輪郭に筋状の凸又は凹部
を生じる場合がある。More specifically, the different surface 1 is molded by embedding a material having a thermal conductivity different from those of other mold cavity surfaces at a preset mold cavity surface position for molding the relevant portion. It is formed by that. Therefore, since the cooling state is different from that of the other surface portions, a difference in gloss may occur. Further, the different surface 1 may be convex or concave, or a streak-like convex or concave may be formed on the contour of the different surface 1 depending on the embedding state of materials having different thermal conductivities.
【００２０】本中空成形品における中空部２は、この異
表面１に対応して形成されているものである。ここで、
異表面１に対応するとは、位置及び形状が厳密に異表面
１と一致している場合のみではなく、ほぼ異表面１が形
成された領域に沿っていることをもいう。従って、例え
ば、図３に示されるように、分断された複数の異表面１
の連なりに沿って中空部２が形成されている場合や、異
表面１が形成された領域に沿って複数の枝分かれ状に中
空部２が形成されている場合でもよい。また、このよう
に異表面１に対応して中空部２が形成されている結果、
中空部２もほぼ予め設定した位置に形成されているもの
である。The hollow portion 2 of the hollow molded article is formed corresponding to the different surface 1. here,
Corresponding to the different surface 1 does not only mean that the position and the shape are exactly the same as the different surface 1, but also means that the position and the shape are substantially along the region where the different surface 1 is formed. Therefore, for example, as shown in FIG. 3, a plurality of divided different surfaces 1
Alternatively, the hollow portion 2 may be formed along the continuous line, or the plurality of branched hollow portions 2 may be formed along the region where the different surface 1 is formed. Further, as a result of forming the hollow portion 2 corresponding to the different surface 1 in this way,
The hollow portion 2 is also formed at a substantially preset position.
【００２１】図１及び図２に示される中空射出成形品に
おいては、成形品のほぼ中央に形成された加圧流体圧入
部３から放射状方向に異表面１及び中空部２が形成され
ている。ここで加圧流体圧入部３とは、加圧流体の圧入
跡として通常成形品に残される小孔である。In the hollow injection-molded article shown in FIGS. 1 and 2, the different surface 1 and the hollow section 2 are formed in the radial direction from the pressurized fluid press-fitting section 3 formed substantially in the center of the article. Here, the pressurizing fluid press-fitting portion 3 is a small hole that is usually left in a molded product as a pressurizing trace of pressurizing fluid.
【００２２】更にこの加圧流体圧入部３について説明す
ると、中空射出成形における加圧流体の圧入は、射出ノ
ズルに内蔵された加圧流体ノズルや、金型に直接設けた
加圧流体ノズルで行われる。射出ノズルに内蔵された加
圧流体ノズルによる場合、加圧流体圧入部３は金型キャ
ビティのゲート部分に相当する箇所に形成される。金型
に直接設けた加圧流体ノズルによる場合、加圧流体圧入
部３は、加圧流体ノズルをスプルーやランナーに開口さ
せるか直接金型キャビティに開口させるかによって、ゲ
ート部分もしくは金型キャビティへの加圧流体ノズル開
口部分に相当する箇所に形成される。The pressurizing fluid press-fitting portion 3 will be further described. The pressurizing fluid is press-fitted in the hollow injection molding by the pressurizing fluid nozzle built in the injection nozzle or the pressurizing fluid nozzle directly provided in the mold. Be seen. In the case of using the pressurized fluid nozzle built in the injection nozzle, the pressurized fluid press-fitting portion 3 is formed at a portion corresponding to the gate portion of the mold cavity. In the case of using the pressurized fluid nozzle directly provided in the mold, the pressurized fluid press-fitting section 3 is connected to the gate portion or the mold cavity depending on whether the pressurized fluid nozzle is opened to the sprue or runner or directly to the mold cavity. Is formed at a location corresponding to the opening of the pressurized fluid nozzle.
【００２３】異表面１の形成位置及び形状、即ちこれに
対応する中空部２の形成位置及び形状は、成形すべき成
形品によって適宜選択されるものであるが、加圧流体圧
入部３から成形品の端部に向かって延在させることが好
ましい。特に金型キャビティ内における射出溶融樹脂の
流動末端方向もしくは成形品端部への最長距離方向に延
在させることが好ましい。成形品の端部、特に金型キャ
ビティ内における溶融樹脂の流動末端側の端部は、金型
キャビティ面への溶融樹脂の密着力が弱くなりやすく、
ヒケを生じやすい箇所であり、この方向へ延在させるこ
とで、当該箇所におけるヒケを防止することができる。The forming position and shape of the different surface 1, that is, the forming position and shape of the hollow portion 2 corresponding to the different surface 1 are appropriately selected depending on the molded product to be molded. It preferably extends towards the edge of the article. In particular, it is preferable to extend the injection molten resin in the mold cavity in the direction of the flow end or in the direction of the longest distance to the end of the molded product. At the end of the molded product, especially the end on the flow end side of the molten resin in the mold cavity, the adhesion of the molten resin to the mold cavity surface tends to be weak,
It is a place where sink marks are likely to occur, and by extending in this direction, sink marks at the places can be prevented.
【００２４】また、異表面１は、２つの異表面１によっ
て囲繞される面積又は体積が各々概略等しくなる位置に
設けることが好ましい。換言すれば、中空部２は、２つ
の中空部２によって囲繞される部分の面積又は体積が各
々概略等しくなる位置に設けることが好ましい。例えば
図１において、Ａ部分とＢ部分の面積はほぼ等しいこと
が好ましい。Ａ部分とＢ部分の厚みが相違する場合、Ａ
部分とＢ部分の体積がほぼ等しくなるよう、異表面１又
は中空部２が設けられていることが好ましい。The different surfaces 1 are preferably provided at positions where the areas or volumes surrounded by the two different surfaces 1 are substantially equal to each other. In other words, it is preferable that the hollow portion 2 is provided at a position where the areas surrounded by the two hollow portions 2 have substantially the same area or volume. For example, in FIG. 1, it is preferable that the areas A and B are substantially equal in area. If the thickness of the A part and the B part are different, A
The different surface 1 or the hollow portion 2 is preferably provided so that the volume of the portion and the volume of the B portion are substantially equal.
【００２５】図１及び図２に示される中空射出成形品に
おいては、異表面１及び中空部２は１本ずつ放射状に伸
びているが、図４及び図５に示されるように異表面１及
び中空部２を途中で分岐させることもできる。また、図
示はされていないが、分岐した異表面１及び中空部２を
更に分岐させることもできる。In the hollow injection-molded article shown in FIGS. 1 and 2, the different surface 1 and the hollow portion 2 extend radially one by one, but as shown in FIGS. The hollow portion 2 can be branched on the way. Although not shown, the branched different surface 1 and the hollow portion 2 can be further branched.
【００２６】また、異表面１及び中空部２は、図６及び
図７に示されるように、加圧流体圧入部３が成形品の一
端部にある場合、当該一端部から対向する他端部側へと
延在させればよい。Further, as shown in FIGS. 6 and 7, when the pressurizing fluid press-fitting portion 3 is located at one end of the molded article, the different surface 1 and the hollow portion 2 are opposite to the other end. Just extend it to the side.
【００２７】本発明に係る中空射出成形品は、板状体で
あることが好ましい。ここで板状体とは、基本的には肉
厚がほぼ一定の平板状のものをいうが、本発明はこれに
限定されるものではなく、例えば波板や湾曲板等の他、
例えばバケツの周壁部等、湾曲もしくは屈曲した、成形
品の一部であってもよく、肉厚に変動があっても全体と
して実質的に板状であればよく、リブ、ボス等の厚肉部
を有する薄肉成形品でもよい。このリブ、ボス等の厚肉
部を有する薄肉成形品とは、自動車のインパネやバンパ
ー、ＯＡ機器や家電製品のハウジング等のように、リブ
やボス等の厚肉部が、板状体の１箇所又は複数箇所に、
単独もしくは連続して形成された成形品である。The hollow injection-molded article according to the present invention is preferably a plate-shaped body. Here, the plate-like body basically means a flat plate-like member having a substantially constant wall thickness, but the present invention is not limited to this, for example, in addition to corrugated plates and curved plates,
For example, it may be a part of a molded product that is curved or bent, such as the peripheral wall of a bucket, and may have a substantially plate-like shape as a whole even if the wall thickness varies. It may be a thin-walled molded product having a portion. The thin-walled molded product having a thick portion such as a rib or a boss means that the thick portion such as a rib or a boss is a plate-like body such as an instrument panel or bumper of an automobile, a housing of OA equipment or a home electric appliance. In multiple locations,
It is a molded product that is formed alone or continuously.
【００２８】次に、図８、図１及び図２で、請求項２及
び３の発明に係る中空射出成形方法について説明する。Next, the hollow injection molding method according to the inventions of claims 2 and 3 will be described with reference to FIGS. 8, 1 and 2.
【００２９】図８は図１及び図２に示される中空射出成
形品を成形するための金型回りを示すもので、図中４は
射出ノズルで、加圧流体ノズル５はこの射出ノズル４に
内蔵されたものとなっている。従って、図１における加
圧流体圧入部３は、ゲート部６に相当する箇所である。FIG. 8 shows a die for molding the hollow injection-molded article shown in FIGS. 1 and 2. In the figure, 4 is an injection nozzle, and pressurized fluid nozzle 5 is the injection nozzle 4. It is built-in. Therefore, the pressurized fluid press-fitting portion 3 in FIG. 1 is a portion corresponding to the gate portion 6.
【００３０】金型は、固定型７ａと移動型７ｂで構成さ
れており、移動型７ｂは固定型７ａに対して進退可能で
ある。The die is composed of a fixed die 7a and a movable die 7b, and the movable die 7b can move forward and backward with respect to the fixed die 7a.
【００３１】固定型７ａ側の金型キャビティ面には断熱
材８が埋設されている。この断熱材８は、図１に示され
る異表面１に相応する位置、即ち中空部２を形成すべき
位置に対応して、ゲート部６から放射状方向設けられて
いる。A heat insulating material 8 is embedded in the mold cavity surface on the fixed mold 7a side. The heat insulating material 8 is provided radially from the gate portion 6 at a position corresponding to the different surface 1 shown in FIG. 1, that is, at a position where the hollow portion 2 is to be formed.
【００３２】断熱材８は、金型構成材料よりも熱伝導率
が低く、溶融樹脂の射出時の温度等に耐えるものであれ
ばよく、例えばポリイミド、エポキシ樹脂、シリコーン
樹脂、テトラフルオロエチレン樹脂、セラミック等を用
いることができる。The heat insulating material 8 may be one having a lower thermal conductivity than the material constituting the mold and can withstand the temperature at the time of injection of the molten resin, such as polyimide, epoxy resin, silicone resin, tetrafluoroethylene resin, Ceramic or the like can be used.
【００３３】本発明に係る中空射出成形は次のようにし
て行われる。Hollow injection molding according to the present invention is performed as follows.
【００３４】まず、金型キャビティ内に所定量の溶融樹
脂を射出した後、加圧流体を圧入する。First, a predetermined amount of molten resin is injected into the mold cavity, and then a pressurized fluid is injected.
【００３５】使用する樹脂としては、一般の射出成形や
押し出し成形に使用される熱可塑性樹脂全般を用いるこ
とができるが、熱硬化性樹脂を用いることもできる。ま
た、必要に応じて各種添加剤、充填材、フィラー等を加
えて用いることもできる。As the resin to be used, general thermoplastic resins used in general injection molding and extrusion molding can be used, but thermosetting resins can also be used. Further, various additives, fillers, fillers and the like can be added and used as necessary.
【００３６】加圧流体としては、常温常圧でガス状又は
液状のもので、射出成形の温度及び圧力下で、成形に用
いる溶融樹脂と反応又は混合されないものが使用され
る。例えば窒素ガス、炭酸ガス、空気、ヘリウムガス、
グリセリン、流動パラフィン、溶融樹脂等であるが、窒
素ガス等の不活性ガスが好ましい、また、加圧流体の圧
力は、一般的には１０〜５００ｋｇ／ｃｍ2 程度であ
る。As the pressurized fluid, a fluid which is gaseous or liquid at room temperature and normal pressure and which does not react or mix with the molten resin used for molding under the temperature and pressure of injection molding is used. For example, nitrogen gas, carbon dioxide gas, air, helium gas,
Glycerin, liquid paraffin, molten resin and the like are preferable, but an inert gas such as nitrogen gas is preferable, and the pressure of the pressurized fluid is generally about 10 to 500 kg / cm 2 .
【００３７】加圧流体圧入のタイミングは、金型キャビ
ティ内を満たすに充分な量の溶融樹脂を射出（フルショ
ット）した後、もしくは、金型キャビティ内を満たすに
足りない量の溶融樹脂を射出（ショートショット）した
後である。The timing of pressurizing fluid injection is after injecting (full shot) a sufficient amount of molten resin to fill the mold cavity, or injecting an insufficient amount of molten resin to fill the mold cavity. After (short shot).
【００３８】フルショットの場合、溶融樹脂が冷却され
て収縮するにつれて、その収縮量に応じて加圧流体が圧
入されることになる。また、ショートショットの場合、
溶融樹脂の未充填容積と樹脂の収縮量に応じた加圧流体
が圧入されることになる。In the case of full shot, as the molten resin cools and contracts, the pressurized fluid is pressed in according to the amount of contraction. For short shots,
The pressurized fluid corresponding to the unfilled volume of the molten resin and the shrinkage amount of the resin is press-fitted.
【００３９】ショートショットの場合、金型キャビティ
の容積の９０％以上を溶融樹脂で満たした後に加圧流体
の圧入を行うことが好ましい。未充填容積が大き過ぎる
と、予め予定した位置に中空部２を形成しにくくなる。
また、ショートショットの場合、更に溶融樹脂の射出を
継続しつつ加圧流体の圧入を行うこともできる。In the case of short shot, it is preferable to pressurize the pressurized fluid after filling 90% or more of the volume of the mold cavity with the molten resin. If the unfilled volume is too large, it becomes difficult to form the hollow portion 2 at a predetermined position.
In the case of a short shot, it is possible to pressurize the pressurized fluid while continuing the injection of the molten resin.
【００４０】ところで、金型キャビティに設けられた断
熱材８は、この断熱材８が設けられた領域に充填された
溶融樹脂の冷却を、他の領域に充填された溶融樹脂より
遅延させるものである。By the way, the heat insulating material 8 provided in the mold cavity delays the cooling of the molten resin filled in the area where the heat insulating material 8 is provided compared with the molten resin filled in the other areas. is there.
【００４１】加圧流体は、流動しやすい箇所を通って圧
入されることから、断熱材８によって冷却が遅延してい
る溶融樹脂中に導かれて、そこに中空部２を形成するこ
とになる。従って、予め予定した位置に中空部２を形成
することができる。Since the pressurizing fluid is pressed through a portion where it easily flows, it is guided into the molten resin whose cooling is delayed by the heat insulating material 8 and forms the hollow portion 2 therein. . Therefore, the hollow portion 2 can be formed at a predetermined position.
【００４２】また、断熱材８に相応する領域の冷却が緩
やかで金型キャビティ面へ圧接されやすいこと、断熱材
８が金型キャビティ表面より突出又は埋没して設けられ
ること、断熱材８の周囲に隙間やめくれ上がりが残存す
ること等の原因により、断熱材８部分で成形された表面
は図１で説明したような異表面１となる。Further, the cooling of the region corresponding to the heat insulating material 8 is gradual, and is easily pressed against the mold cavity surface, the heat insulating material 8 is provided so as to project or be buried from the mold cavity surface, and the periphery of the heat insulating material 8 The surface formed by the heat insulating material 8 becomes the different surface 1 as described with reference to FIG.
【００４３】このようにして加圧流体を圧入した後は、
所定の保持時間及び冷却完了後、中空部２内の加圧流体
を排出して成形品を取り出せばよい。After pressurizing the pressurized fluid in this manner,
After the predetermined holding time and the completion of cooling, the pressurized fluid in the hollow portion 2 may be discharged to take out the molded product.
【００４４】断熱材８の設置位置は、成形品の形状や大
きさ等によって選択されれる、中空部２を形成すべき位
置に対応して定められるもので、上記のように異表面１
に相応した位置であることから、具体的には、例えば図
１、図４及び図６に示される異表面１の位置に相応した
位置が挙げられる。The installation position of the heat insulating material 8 is determined in accordance with the position where the hollow portion 2 is to be formed, which is selected according to the shape and size of the molded product, and as described above, the different surface 1
Since it is a position corresponding to, the position corresponding to the position of the different surface 1 shown in FIGS. 1, 4 and 6 can be specifically mentioned.
【００４５】断熱材８は、図８に示されるように、固定
型７ａと移動型７ｂの一方の面のみではなく、両者の面
に相対向させて設けることもできる。固定型７ａと移動
型７ｂの一方にのみ断熱材８を設ける場合であって、成
形品の衣装面側に設ける場合には移動型７ｂ側とするこ
とが効果的である。As shown in FIG. 8, the heat insulating material 8 may be provided not only on one surface of the fixed mold 7a and the movable mold 7b but also on both surfaces thereof so as to face each other. When the heat insulating material 8 is provided only on one of the fixed die 7a and the movable die 7b, and when it is provided on the costume surface side of the molded product, it is effective to use the movable die 7b side.
【００４６】更に、加圧流体圧入開始と同時、加圧流体
圧入途中又は加圧流体圧入完了後に移動型７ｂを後退さ
せて金型キャビティを拡大することもできる。この金型
キャビティの拡大を行うと、拡大された金型キャビティ
容積に応じて各中空部２が拡大され、中空部２の大きな
中空射出成形品を得ることができる。Further, the mold cavity can be enlarged by retracting the movable die 7b at the same time when the pressurization fluid press-fitting is started, during the pressurization fluid press-fitting or after the pressurization fluid press-fitting is completed. When this mold cavity is expanded, each hollow part 2 is expanded according to the expanded mold cavity volume, and a hollow injection-molded product with a large hollow part 2 can be obtained.
【００４７】断熱材８の付設に代えて、上記断熱材８を
設ける領域以外の領域に伝熱材を設けることもできる。
即ち、伝熱材を設けた領域における溶融樹脂の冷却を早
めることで、相対的に、伝熱材の設けられていない領
域、つまり中空部２を形成すべき領域における溶融樹脂
の冷却を遅延させることができる。また、この伝熱材の
設置を断熱材８の設置と併用することもできる。Instead of providing the heat insulating material 8, a heat transfer material may be provided in an area other than the area where the heat insulating material 8 is provided.
That is, the cooling of the molten resin in the region where the heat transfer material is provided is accelerated to relatively delay the cooling of the molten resin in the region where the heat transfer material is not provided, that is, the region where the hollow portion 2 is to be formed. be able to. Further, the installation of this heat transfer material can be used together with the installation of the heat insulating material 8.
【００４８】伝熱材としては、金型構成材料より熱伝導
率が高く、溶融樹脂の射出時の温度等に耐えるものであ
ればよく、例えば金型構成材料が炭素鋼の場合、アルミ
ニウム、グラファイト、モリブテン、タングステン、マ
グネシウム、ベリリウム、銅、銀等又はこれらの合金を
用いることができる。As the heat transfer material, any material may be used as long as it has a higher thermal conductivity than the mold constituent material and can withstand the temperature at the time of injection of the molten resin. For example, when the mold constituent material is carbon steel, aluminum or graphite. , Molybdenum, tungsten, magnesium, beryllium, copper, silver and the like or alloys thereof can be used.
【００４９】また、断熱材８の付設に代えて、金型構成
材料と同じ材料のブロックもしくは板状の入れ子を、図
８に示される断熱材８と同様に金型に嵌め込むこともで
きる。この場合、入れ子と金型との間に残される隙間内
の空気が断熱層となって、入れ子が冷却されにくい状態
となるので、断熱材８を設けた場合と同様の効果を得る
ことができる。Instead of attaching the heat insulating material 8, a block or plate-shaped insert made of the same material as the material forming the mold may be fitted in the mold in the same manner as the heat insulating material 8 shown in FIG. In this case, the air in the gap left between the insert and the mold serves as a heat insulating layer, which makes it difficult for the insert to be cooled. Therefore, the same effect as when the heat insulating material 8 is provided can be obtained. .
【００５０】[0050]
【実施例】図７に示されるような中空射出成形装置を用
い、図１及び図２に示されるような中空射出成形品を成
形した。断熱材８としてはエポキシ樹脂を使用した。EXAMPLE A hollow injection molded article as shown in FIGS. 1 and 2 was molded using a hollow injection molding apparatus as shown in FIG. An epoxy resin was used as the heat insulating material 8.
【００５１】成形条件は次の通りである。The molding conditions are as follows.
【００５２】使用樹脂：ポリスチレン（旭化成工業社製
「＃４００」をカーボンで黒色に着色したもの） 成形温度：２２０℃ 溶融樹脂の射出時間：１．７４ｓｅｃ（フルショット） 使用加圧流体：窒素ガス 加圧流体圧入遅延時間（射出完了後圧入開始までの時
間）：２ｓｅｃ 加圧流体の圧入及び保持時間：１５ｓｅｃ 冷却時間：３０ｓｅｃResin used: polystyrene (Asahi Kasei Kogyo's "# 400" colored black with carbon) Molding temperature: 220 ° C. Injection time of molten resin: 1.74 sec (full shot) Pressurized fluid used: Nitrogen gas Pressurized fluid press-in delay time (time from completion of injection until start of pressurization): 2 sec Pressurized fluid press-fit and hold time: 15 sec Cooling time: 30 sec
【００５３】得られた中空射出成形品は、断熱材８に相
応する位置に、中央部から放射状に伸びた異表面１を有
し、この異表面１に対応して中空部２が形成されてい
て、反りのない良好なものであった。また、異表面１は
その周辺より光沢度の高い表面となった。The obtained hollow injection-molded product has a different surface 1 radially extending from the central portion at a position corresponding to the heat insulating material 8, and a hollow portion 2 is formed corresponding to the different surface 1. It was a good one with no warp. Further, the different surface 1 has a higher glossiness than that of the surrounding area.
【００５４】実施例２ 実施例１において断熱材８を設けたことに代えて、この
断熱材８を設けた領域以外の領域に、アルミニウムの伝
熱材を設けた金型を用いた以外は実施例１と同様にして
同様の中空射出成形品を成形した。Example 2 In place of providing the heat insulating material 8 in the first embodiment, a mold having an aluminum heat transfer material provided in a region other than the region having the heat insulating material 8 was used. The same hollow injection-molded article was molded in the same manner as in Example 1.
【００５５】その結果、実施例１と同様の良好な中空射
出成形品が得られた。また、異表面１はその周囲より光
沢度の高い表面となった。As a result, the same good hollow injection-molded article as in Example 1 was obtained. In addition, the different surface 1 has a higher glossiness than the surrounding area.
【００５６】実施例３及び４ 使用樹脂をＡＢＳ樹脂（旭化成工業社製「ＡＴ３０」）
とし、成形温度を２４０℃とした以外は実施例１及び２
と同様にして同様の成形を行った。得られた中空射出成
形品は実施例１及び２と同様であった。Examples 3 and 4 Resin used was ABS resin ("AT30" manufactured by Asahi Kasei Corporation).
And Examples 1 and 2 except that the molding temperature was 240 ° C.
The same molding was performed in the same manner as in. The obtained hollow injection-molded article was the same as in Examples 1 and 2.
【００５７】[0057]
【発明の効果】本発明は、以上説明した通りのものであ
り、次の効果を奏するものである。The present invention is as described above and has the following effects.
【００５８】（１）中空部２を均一に分散させて形成す
ることができるので、偏った中空部２に形成を防止で
き、反りのない成形品となる。(1) Since the hollow portions 2 can be formed by being uniformly dispersed, formation of the uneven hollow portions 2 can be prevented, and a molded product having no warp can be obtained.
【００５９】（２）過剰に広い領域に亙る中空部２が形
成されてしまうことによる強度低下を防止することがで
きる。(2) It is possible to prevent a decrease in strength due to the formation of the hollow portion 2 over an excessively wide area.
【００６０】（３）中空部２を所定位置に形成するため
の厚肉部が不要で、中空部２の形成位置に沿って厚肉部
を形成する場合のように、中空部２の形成位置について
の制限を受けない。また、この厚肉部の形成に伴う、反
対面でのひけや艶むら等の外観不良を生じることもな
い。(3) A thick portion for forming the hollow portion 2 at a predetermined position is not required, and the forming position of the hollow portion 2 is the same as in the case of forming the thick portion along the forming position of the hollow portion 2. Not be restricted. Further, the appearance defect such as sink mark or uneven gloss on the opposite surface due to the formation of the thick portion does not occur.
【００６１】（４）断熱材８や伝熱材の付設するだけ
で、大掛かりな金型の変更を行うことなく、中空部２を
形成する位置を定めることができ、設備的負担が小さ
い。(4) The position where the hollow portion 2 is formed can be determined by simply attaching the heat insulating material 8 and the heat transfer material, and the position of forming the hollow portion 2 can be determined, so that the facility load is small.
【図１】請求項１の発明に係る中空射出成形品の第１の
例を示す斜視図である。FIG. 1 is a perspective view showing a first example of a hollow injection-molded article according to the invention of claim 1.
【図２】図１に示される中空射出成形品の横断面図であ
る。2 is a cross-sectional view of the hollow injection-molded article shown in FIG.
【図３】異表面と中空部の他の関係を示す平面図であ
る。FIG. 3 is a plan view showing another relationship between the different surface and the hollow portion.
【図４】請求項１の発明に係る中空射出成形品の第２の
例を示す斜視図である。FIG. 4 is a perspective view showing a second example of the hollow injection-molded article according to the invention of claim 1.
【図５】図４に示される中空射出成形品の横断面図であ
る。5 is a cross-sectional view of the hollow injection-molded article shown in FIG.
【図６】請求項１の発明に係る中空射出成形品の第３の
例を示す斜視図である。FIG. 6 is a perspective view showing a third example of a hollow injection-molded article according to the invention of claim 1.
【図７】図６に示される中空射出成形品の横断面図であ
る。7 is a cross-sectional view of the hollow injection-molded article shown in FIG.
【図８】請求項２及び３の発明の説明図である。FIG. 8 is an explanatory diagram of the invention of claims 2 and 3;
１ 異表面 ２ 中空部 ３ 加圧流体圧入部 ４ 射出ノズル ５ 加圧流体ノズル ６ ゲート部 ７ａ 固定型 ７ｂ 移動型 ８ 断熱材 1 Different Surface 2 Hollow Part 3 Pressurized Fluid Press-In Part 4 Injection Nozzle 5 Pressurized Fluid Nozzle 6 Gate Part 7a Fixed Type 7b Movable Type 8 Insulation Material
Claims (3)
て異表面が形成されており、この異表面に対応して中空
部が形成されていることを特徴とする中空射出成形品。1. A hollow injection-molded article, characterized in that a different surface is formed at a predetermined position on the surface as compared with the periphery, and a hollow portion is formed corresponding to the different surface.
キャビティ表面が、その他の金型キャビティ表面より熱
伝導率の低い材料で構成された金型を用いることを特徴
とする中空射出成方法。2. A hollow injection molding method, wherein a mold cavity surface corresponding to a position where a predetermined hollow portion is formed is made of a material having a lower thermal conductivity than other mold cavity surfaces. Method.
以外の金型キャビティ表面が、所定の中空部の形成位置
に対応する金型キャビティ表面より熱伝導率の高い材料
で構成された金型を用いることを特徴とする中空射出成
形方法。3. A mold cavity surface other than a position corresponding to a predetermined hollow portion forming position is made of a material having a higher thermal conductivity than a mold cavity surface corresponding to a predetermined hollow portion forming position. A hollow injection molding method characterized by using a mold.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25093593A JP3254063B2 (en) | 1993-09-14 | 1993-09-14 | Hollow injection molding method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25093593A JP3254063B2 (en) | 1993-09-14 | 1993-09-14 | Hollow injection molding method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0780883A true JPH0780883A (en) | 1995-03-28 |
| JP3254063B2 JP3254063B2 (en) | 2002-02-04 |
Family
ID=17215211
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25093593A Expired - Fee Related JP3254063B2 (en) | 1993-09-14 | 1993-09-14 | Hollow injection molding method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3254063B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0806272A1 (en) * | 1994-11-25 | 1997-11-12 | Asahi Kasei Kogyo Kabushiki Kaisha | Improved injection molding method for producing resin blow molded article and mold used for said method |
| WO2005018902A1 (en) * | 2003-08-22 | 2005-03-03 | Suzuka Fuji Xerox Co., Ltd. | Hollow molded product, method of manufacturing hollow molded product, and metal mold for hollow molding |
-
1993
- 1993-09-14 JP JP25093593A patent/JP3254063B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0806272A1 (en) * | 1994-11-25 | 1997-11-12 | Asahi Kasei Kogyo Kabushiki Kaisha | Improved injection molding method for producing resin blow molded article and mold used for said method |
| EP0806272A4 (en) * | 1994-11-25 | 1998-07-08 | Asahi Chemical Ind | Improved injection molding method for producing resin blow molded article and mold used for said method |
| WO2005018902A1 (en) * | 2003-08-22 | 2005-03-03 | Suzuka Fuji Xerox Co., Ltd. | Hollow molded product, method of manufacturing hollow molded product, and metal mold for hollow molding |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3254063B2 (en) | 2002-02-04 |
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