JPH0343967B2 - - Google Patents
Info
- Publication number
- JPH0343967B2 JPH0343967B2 JP17006783A JP17006783A JPH0343967B2 JP H0343967 B2 JPH0343967 B2 JP H0343967B2 JP 17006783 A JP17006783 A JP 17006783A JP 17006783 A JP17006783 A JP 17006783A JP H0343967 B2 JPH0343967 B2 JP H0343967B2
- Authority
- JP
- Japan
- Prior art keywords
- mold
- synthetic resin
- injection
- molded
- molded product
- 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.)
- Expired
Links
- 229920003002 synthetic resin Polymers 0.000 claims description 37
- 239000000057 synthetic resin Substances 0.000 claims description 37
- 239000000945 filler Substances 0.000 claims description 17
- 238000001746 injection moulding Methods 0.000 claims description 16
- 229920001169 thermoplastic Polymers 0.000 claims description 11
- 239000004416 thermosoftening plastic Substances 0.000 claims description 11
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 238000002347 injection Methods 0.000 description 28
- 239000007924 injection Substances 0.000 description 28
- 239000010410 layer Substances 0.000 description 12
- 238000000465 moulding Methods 0.000 description 10
- 239000002344 surface layer Substances 0.000 description 10
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 description 7
- 239000004793 Polystyrene Substances 0.000 description 5
- 229920002223 polystyrene Polymers 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 239000011231 conductive filler Substances 0.000 description 4
- 238000001816 cooling Methods 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 229910001369 Brass Inorganic materials 0.000 description 3
- 239000004743 Polypropylene Substances 0.000 description 3
- 239000010951 brass Substances 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 238000009472 formulation Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229920000515 polycarbonate Polymers 0.000 description 3
- 239000004417 polycarbonate Substances 0.000 description 3
- -1 polypropylene Polymers 0.000 description 3
- 229920001155 polypropylene Polymers 0.000 description 3
- 239000004800 polyvinyl chloride Substances 0.000 description 3
- 229920000915 polyvinyl chloride Polymers 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000004721 Polyphenylene oxide Substances 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920006380 polyphenylene oxide Polymers 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229920001410 Microfiber Polymers 0.000 description 1
- 229920000265 Polyparaphenylene Polymers 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000003658 microfiber Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
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
- B29C45/16—Making multilayered or multicoloured articles
- B29C45/1615—The materials being injected at different moulding stations
- B29C45/1628—The materials being injected at different moulding stations using a mould carrier rotatable about an axis perpendicular to the opening and closing axis of the moulding stations
-
- 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
- B29C45/0013—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor using fillers dispersed in the moulding material, e.g. metal particles
-
- 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
- B29C45/16—Making multilayered or multicoloured articles
- B29C2045/1682—Making multilayered or multicoloured articles preventing defects
-
- 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
- B29C45/0025—Preventing defects on the moulded article, e.g. weld lines, shrinkage marks
-
- 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
- B29C45/03—Injection moulding apparatus
- B29C45/04—Injection moulding apparatus using movable moulds or mould halves
- B29C45/0441—Injection moulding apparatus using movable moulds or mould halves involving a rotational movement
- B29C45/045—Injection moulding apparatus using movable moulds or mould halves involving a rotational movement mounted on the circumference of a rotating support having a rotating axis perpendicular to the mould opening, closing or clamping direction
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Description
本発明は射出成形におけるヒケ防止方法に関す
るものである。
例えば第１図に示すように裏面にボス３２のよ
うな凸部を有するパネル３１を熱可塑性合成樹脂
によつて成形する際には、金型３３のキヤビテイ
ー３４内に熱可塑性合成樹脂材料を射出するので
あるが、ボス成形部３４Ａ内に材料が流入して冷
却する際の体積収縮によつてパネル３１の表面の
ボス３２にあたる位置に一般にヒケ３１Ａと呼ば
れる凹状欠陥が生じ、外観的にみて大きな問題を
生じている。パネル３１表面に更に熱可塑性合成
樹脂材料を射出して表層を形成する二段射出成形
の場合でも、表層の射出成形を後段で行なうと前
段で形成されたヒケ部分に表層の熱可塑性合成樹
脂材料が陥入して表層表面に凹状欠陥が発生す
る。表層を前段で射出成形する場合は表層表面に
凹状欠陥が発生しないであろうが、パネル３１と
表層との間にヒケ３１Ａによる空洞が形成され、
表層の密着性が低下する。
本発明は上記従来の問題点を解消することを目
的とし、片面に凸部を有する成形物を製造する
際、熱可塑性合成樹脂を複数段射出成形して多層
構造とし、少なくとも凸部を有する側は容積率10
〜25％の金属充填材を混合した熱可塑性合成樹脂
によつて射出成形することを骨子とするものであ
る。
以下本発明を詳細に説明する。
本発明に用いる熱可塑性合成樹脂を例示すれば
ポリ塩化ビニル、ポリアミドABSポリスチレン、
ポリフエニレンオキサイド、ポリプロピレン、ポ
リエチレン、ポリカーボネートなどである。望ま
しくは射出成形に適する点、熱良導性充填材の混
入に適する点、成形物の凸部を有しない側に使用
する熱可塑性合成樹脂（以下合成樹脂Ａとする）
と、成形物の凸部を有する側に使用する熱良導性
充填材を混合した熱可塑性合成樹脂（以下合成樹
脂Ｂとする）との相溶性が良い点などから合成樹
脂Ｂと、合成樹脂Ａは、例えば以下の組み合わせ
が望ましい。ポリスチレン−ポリスチレン・ポリ
フエニレンオキサイド、ABS−ABS・ポリカー
ボネート・ポリ塩化ビニル、ポリアミド−ポリア
ミド、ポリカーボネート−ABS・ポリカーボネ
ート、ポリプロピレン−ポリエチレン・ポリプロ
ピレン、ポリフエニレンオキサイド−ポリプロピ
レン・ポリスチレン、ポリ塩化ビニル−ABS・
ポリメチルメタクリレート・ポリ塩化ビニル。
本発明に用いる金属充填材（以下単に充填材と
言う）とは例えば黄銅、真ちゆう、銀、銅、ニツ
ケル、ステンレス等の金属の粉末状、繊維状、リ
ボン状、フレーク状等の形状を有する微小体、あ
るいは上記金属をコートしたガラス、プラスチツ
ク、セラミツク等の微小体から適宜選択して用い
ることができる。
前記合成樹脂Ｂに添加される充填材は一種だけ
でもよいしまた数種適当に混合して使用してもよ
い。また合成樹脂Ｂに添加する充填材の添加量
は、合成樹脂Ｂの種類または充填材の種類および
その組み合わせによつて異なるが、用途に応じて
適宜選定することができる。しかし、流れ性、混
和性の点から充填材の望ましい形状は厚みが0.1
ｍ／ｍ以下で大きな面の面積が４mm2以下のフレー
クか、径(D)が10〜100μｍで流さ(L)が１〜４ｍ／
ｍの微小繊維が望ましい。更に合成樹脂Ｂと充填
材の比率はヒケの防止性と流れ性からみて、充填
材の容積率として10〜25％にすべきである。
第１表に代表的な配合例を示す。
The present invention relates to a method for preventing sink marks in injection molding. For example, when molding a panel 31 having a convex portion such as a boss 32 on the back surface using thermoplastic synthetic resin as shown in FIG. 1, the thermoplastic synthetic resin material is injected into the cavity 34 of the mold 33. However, due to the volumetric contraction when the material flows into the boss molding part 34A and cools, a concave defect generally called a sink mark 31A occurs on the surface of the panel 31 at the position corresponding to the boss 32, which is large in terms of appearance. It's causing problems. Even in the case of two-stage injection molding in which a thermoplastic synthetic resin material is further injected onto the surface of the panel 31 to form a surface layer, if injection molding of the surface layer is performed in the latter stage, the thermoplastic synthetic resin material of the surface layer will be applied to the sink area formed in the previous stage. Invagination causes concave defects on the surface layer surface. If the surface layer is injection molded in the previous stage, no concave defects will occur on the surface layer surface, but a cavity due to the sink mark 31A will be formed between the panel 31 and the surface layer.
The adhesion of the surface layer decreases. The present invention aims to solve the above-mentioned conventional problems, and when manufacturing a molded product having a convex portion on one side, a thermoplastic synthetic resin is injection molded in multiple stages to form a multilayer structure, and at least the side having the convex portion is is the volume ratio 10
The main idea is injection molding of thermoplastic synthetic resin mixed with ~25% metal filler. The present invention will be explained in detail below. Examples of thermoplastic synthetic resins used in the present invention include polyvinyl chloride, polyamide ABS polystyrene,
These include polyphenylene oxide, polypropylene, polyethylene, and polycarbonate. A thermoplastic synthetic resin (hereinafter referred to as synthetic resin A) that is preferably suitable for injection molding, suitable for incorporating a thermally conductive filler, and used on the side of the molded product that does not have a convex portion.
Synthetic resin B and synthetic resin have good compatibility with the thermoplastic synthetic resin mixed with a thermally conductive filler (hereinafter referred to as synthetic resin B) used on the side with the convex portion of the molded product. For example, the following combinations of A are desirable. Polystyrene-polystyrene/polyphenylene oxide, ABS-ABS/polycarbonate/polyvinyl chloride, polyamide-polyamide, polycarbonate-ABS/polycarbonate, polypropylene-polyethylene/polypropylene, polyphenylene oxide-polypropylene/polystyrene, polyvinyl chloride-ABS/
Polymethyl methacrylate/polyvinyl chloride. The metal filler used in the present invention (hereinafter simply referred to as filler) refers to metals such as brass, brass, silver, copper, nickel, and stainless steel in the form of powder, fiber, ribbon, flake, etc. It is possible to appropriately select and use microscopic bodies made of glass, plastic, ceramic, etc. coated with the above-mentioned metals. Only one type of filler may be added to the synthetic resin B, or several types may be appropriately mixed and used. The amount of filler added to synthetic resin B varies depending on the type of synthetic resin B, the type of filler, and the combination thereof, and can be appropriately selected depending on the application. However, from the viewpoint of flowability and miscibility, the preferred shape of the filler is a thickness of 0.1
m/m or less with a large surface area of 4 mm2 or less, or a diameter (D) of 10 to 100 μm and a flow rate (L) of 1 to 4 m/m.
m microfibers are preferred. Furthermore, the ratio of the synthetic resin B to the filler should be 10 to 25% as a volume percentage of the filler in view of sink mark prevention and flowability. Table 1 shows typical formulation examples.
【表】
次に本発明は、いわゆる２色射出成形機のよう
な射出ユニツトを２基備えた装置によつて達成す
ることが出来るが、第２図以下に示す一実施例に
もとづいて以下に詳細に説明する。
第１表の配合例に従い合成樹脂Ｂに充填材を添
加し、押出機にて均一に混練されて作製されたコ
ンパウンドは第２図に示す一次側射出ユニツト１
のホツパー２に投入され、射出シリンダ３内で可
塑化溶融される。また二次側射出ユニツト４のホ
ツパー５には前記組み合わせより適宜選定された
合成樹脂Ａが投入され、射出シリンダ６内で可塑
化溶融される。７は一次側金型で第３図に示すよ
うに８は一次側可動金型であり、一次側可動定盤
９に固定されている。１０は一次側固定金型であ
り水平方向に回転可能に支持された回転定盤１１
に固定されている。一次側可動金型８と一次側固
定金型１０によつてボス成形部１２Ａを有し成形
品裏面部を形成する金型キヤビテイ１２が構成さ
れている。１３はダイレクトゲートである。また
１４は二次側金型で１５は二次側可動金型であ
り、二次側可動定盤１６に固定されている。１７
は二次側固定金型であり回転定盤１１に固定され
ている。一次側固定金型１０と二次側固定金型１
７のコア部分１８はそれぞれ全く同様の形状寸法
に製作されている。二次側可動金型のキヤビテイ
部分は、一次側可動金型のキヤビテイ部より成形
品外表面層の肉厚分だけ深く製作されている。１
９はダイレクトゲートである。
さて、射出シリンダ３で充填材２３を混合した
合成樹脂Ｂは可塑化溶融されてダイレクトゲート
１３を通つて金型キヤビテイ１２に充填され、成
形品のボス２０Ａを有する裏面部成形体２０を形
成する。適当な冷却時間を経た後、型開きが行わ
れる。型開き後ダイレクトゲート部分は適当な切
断装置（図示しない）で切断除去される。この
後、回転定盤が水平方向に180°回転し、一次側固
定金型１０と二次側固定金型１７を入れ替える。
すなわち一次側固定金型１０はボス２０Ａを有す
る裏面部成形体２０を着けたまま二次側固定金型
１７のあつた位置へ来るわけである。その後型締
めが行われ、射出シリンダ６で可塑化溶融された
合成樹脂Ａはダイレクトゲート１９を通つて二次
側可動金型１５のキヤビテイ部と裏面部成形体２
０との間に構成される金型キヤビテイ部分２１に
充填されて表面部成形体２４を形成しかくして第
４図に示すような裏面部成形体２０と表面部成形
体２４とが一体に融着された成形品２２となるの
である。適当な冷却時間を経た後型開きが行われ
成形品２２が取り出されダイレクトゲート部を切
断される。こうして第４図に示すような表面部成
形体２４が合成樹脂Ａ層からなり裏面部成形体２
０が合成樹脂Ｂ層からなる成形品２２が得られる
のである。
なお以上の説明ではゲートはダイレクトゲート
としたが、合成樹脂Ｂにはフアンゲート、トンネ
ルゲート等が使用可能であるし、合成樹脂Ａには
ダイレクトゲート以外の公知のゲート形式がすべ
て使用可能であることは言うまでもない。
また、外表面部分を先に成形した後、裏面部分
を射出成形して一体に融着した成形品を得ること
も可能である。
上記射出成形において充填材２３を含む合成樹
脂Ｂは冷却による体積収縮が極めて小さいと言う
予期せざる結果を得た。したがつて裏面部成形体
２０の表面のボス２０Ａにあたる位置にはヒケが
発生せず、かくして表面が平滑で外観的に望まし
い成形品２２が得られるのである。更に充填材２
３は導電性を有し、したがつて電磁波遮断性を有
するから成形品自体も電磁波遮断性を有するに至
り、電子機器のハウジング等の成形に本発明を適
用することは極めて望ましいことである。また本
発明は上記実施例により限定せられるものではな
く、例えば裏面部成形体に先立つて表面部成形体
を成形してもよく、また更にはボスに代えてフラ
ンジ、ブラケツト、リブ、段部等の凸部が形成さ
れてもよい。また更に本発明においては成形品全
体を合成樹脂Ｂで成形してもよいが、本実施例の
ように表面部成形体に合成樹脂Ａを用いて二層構
造にすれば成形品の表面に充填材が存在しないた
め電子機器のハウジング等に用いた場合感電の危
険性もなくなり、また充填材が空気に触れて変性
することも防止され、更に充填材使用量を減らし
て成形品を安価に得ることが出来るのである。そ
して二層構造の場合は前記したようにまずいづれ
か一方の層を成形し次いで他方の層を成形するの
であるが、最初に成形した層が冷却しないうちに
他の層を成形しても本発明においてはヒケを生じ
ない。
以下に本発明を更に具体的に説明するための実
施例について述べるが、以下の実施例は本発明を
限定するものではない。
実施例 １
ABS樹脂75容積％（以下単に％とする）アル
ミニウムフレーク13％、アルミニウム繊維３％を
混合し、押出機にかけ混練、押出後カツトして合
成樹脂Ｂのペレツト化したコンパウンドを用いて
一次側射出ユニツト、一次側コンパウンドを用い
て一次側射出ユニツト、一次側金型により、厚さ
３ｍ／ｍ、外形寸法197×247×28.5ｍ／ｍの箱型
をしボスを有する裏面部成形体を射出成形し、冷
却、型開き、ダイレクトゲート切断除去後得られ
た裏面部成形体を一次側固定金型につけたまま回
転定盤を180°回転して二次側金型へ入れ替えを行
い、二次側射出ユニツトにより白色に着色した
ABS樹脂（合成樹脂Ｂ）を用いて外表面部分を
射出成形し、外表面部成形体と裏面部成形体が融
着一体化された外形寸法200×250×30mm、厚さ
4.5mmの箱型成形物を得た。
射出成形の条件は一次側が金型温度60℃、射出
圧1200Kg／cm2、成形温度230℃、射出時間２秒と
した。また二次側は、金型温度60℃、射出圧1000
Kg／cm2、成形温度220℃、射出時間1.5秒であつ
た。
得られた成形品は外表面に厚さ1.5ｍ／ｍの白
色ABS層を有し、裏面部に導電性フイラーを含
有する厚さ３ｍ／ｍの層を有するものでヒケを生
じず良好な表面平滑性を示すとともに裏面の絶縁
性も優れたものであつた。
また電磁波遮断特性についてW.D.Nason等の
方法に準じて測定すると100MHzで40dBのシール
ド性を示し、デジタル電子装置のプラスチツク製
ハウジングとして使用しても電磁波障害を起こす
恐れのないものであつた。
合成樹脂Ａ層と合成樹脂Ｂ層の境界は、射出成
形時に完全に融着しており強度上も何ら問題のな
いものであつた。
実施例 ２
一次側射出ユニツト及び一次側金型によりベー
ジユ色に着色したポリスチレン（合成樹脂Ａ）を
射出成形して外形寸法400×300×50mm、厚さ1.5
ｍ／ｍの箱型表面層部分を成形した金型は３枚プ
レート形式とし、２点ゲートのピンゲートとし、
型開きと同時にゲートが切断されるようにした。
射出成形条件は金型温度50℃、射出圧1000Kg／
cm2、成形温度210℃、射出時間２秒であつた。
型開き後、回転定盤を180°回転して得られた表
面部成形体を着けたまま、一次側固定金型と二次
側固定金型を入れ替え、型締め後、二次側射出ユ
ニツトによつて下記の処方のコンパウンド（合成
樹脂Ｂ）を裏面部分に射出成形して、表面部成形
体と裏面部成形体とが融着一体化された外形寸法
400×300×50ｍ／ｍ、厚さ５ｍ／ｍの箱型成形品
を得た。この場合のコンパウンド（合成樹脂Ｂ）
としてはポリスチレン75％、真ちゆう繊維３％、
アルミニウムフレーク18％、アルミニウム繊維４
％を単軸の押出機にかけ混練、押出後カツトして
ペレツト化したものを用い、射出成形条件は金型
温度50℃、射出圧1100Kg／cm2、成形温度210℃、
射出時間３秒であつた。成形後ゲート部分を切断
仕上を行つた。
得られた成形品は、表面がベージユ色でヒケが
なく平滑で美麗な外観を有し、表面絶縁性が優
れ、十分な電磁波遮断性及び強度を有するもので
あつた。[Table] Next, the present invention can be achieved by a device equipped with two injection units, such as a so-called two-color injection molding machine. Explain in detail. A compound prepared by adding a filler to synthetic resin B according to the formulation example in Table 1 and uniformly kneading it in an extruder is shown in the primary injection unit 1 shown in Fig. 2.
It is put into a hopper 2 and plasticized and melted in an injection cylinder 3. Further, a synthetic resin A suitably selected from the above combination is charged into the hopper 5 of the secondary injection unit 4, and is plasticized and melted within the injection cylinder 6. 7 is a primary side mold, and as shown in FIG. 3, 8 is a primary side movable mold, which is fixed to a primary side movable surface plate 9. Reference numeral 10 denotes a primary side fixed mold, and a rotary surface plate 11 is rotatably supported in the horizontal direction.
Fixed. The primary movable mold 8 and the primary fixed mold 10 constitute a mold cavity 12 having a boss molding portion 12A and forming the back surface of the molded product. 13 is a direct gate. Further, 14 is a secondary mold, and 15 is a secondary movable mold, which is fixed to a secondary movable surface plate 16. 17
is a secondary side fixed mold and is fixed to the rotating surface plate 11. Primary side fixed mold 10 and secondary side fixed mold 1
The core portions 18 of 7 are each manufactured to have exactly the same shape and dimensions. The cavity portion of the secondary movable mold is made deeper than the cavity portion of the primary movable mold by the thickness of the outer surface layer of the molded product. 1
9 is a direct gate. Now, the synthetic resin B mixed with the filler 23 is plasticized and melted in the injection cylinder 3, and is filled into the mold cavity 12 through the direct gate 13 to form the back surface molded body 20 having the boss 20A of the molded product. . After a suitable cooling time, the mold is opened. After opening the mold, the direct gate portion is cut and removed using a suitable cutting device (not shown). Thereafter, the rotary surface plate rotates 180° in the horizontal direction, and the primary fixed mold 10 and the secondary fixed mold 17 are replaced.
That is, the primary stationary mold 10 comes to the position where the secondary stationary mold 17 is located, with the back molded body 20 having the boss 20A still attached. Thereafter, mold clamping is performed, and the plasticized and melted synthetic resin A in the injection cylinder 6 passes through the direct gate 19 to the cavity part of the secondary movable mold 15 and the back part molded body 2.
0 to form a surface molded body 24. Thus, the back molded body 20 and the front molded body 24 are fused together as shown in FIG. This results in a molded product 22. After an appropriate cooling time, the mold is opened, the molded product 22 is taken out, and the direct gate portion is cut. In this way, the front side molded body 24 as shown in FIG. 4 is made of the synthetic resin A layer, and the back side molded body 2
A molded article 22 in which 0 is the synthetic resin B layer is obtained. In the above explanation, the gate is a direct gate, but a fan gate, a tunnel gate, etc. can be used for the synthetic resin B, and all known gate types other than the direct gate can be used for the synthetic resin A. Needless to say. It is also possible to obtain a molded product in which the outer surface portion is molded first and then the back surface portion is injection molded and fused together. In the above injection molding, an unexpected result was obtained in which the volumetric shrinkage of the synthetic resin B containing the filler 23 upon cooling was extremely small. Therefore, no sink marks occur at the positions corresponding to the bosses 20A on the surface of the back molded body 20, and thus a molded product 22 with a smooth surface and a desirable appearance can be obtained. Furthermore, filler 2
Since No. 3 has conductivity and therefore has electromagnetic wave shielding properties, the molded product itself also has electromagnetic wave shielding properties, and it is extremely desirable to apply the present invention to molding of housings of electronic devices, etc. Furthermore, the present invention is not limited to the above-mentioned embodiments; for example, the front surface molded body may be molded prior to the back surface molded body, and furthermore, the boss may be replaced with a flange, bracket, rib, step, etc. A convex portion may be formed. Furthermore, in the present invention, the entire molded article may be molded with synthetic resin B, but if synthetic resin A is used for the surface molded body to form a two-layer structure as in this example, the surface of the molded article will be filled. Since there is no filler, there is no danger of electric shock when used in electronic device housings, etc., and the filler is also prevented from deteriorating when exposed to air, further reducing the amount of filler used and producing molded products at low cost. It is possible. In the case of a two-layer structure, one of the layers is molded first and then the other layer as described above, but even if the other layer is molded before the first layer is cooled, the present invention still applies. It does not cause sink marks. Examples will be described below to further specifically explain the present invention, but the following examples are not intended to limit the present invention. Example 1 ABS resin 75% by volume (hereinafter simply referred to as %), aluminum flakes 13%, and aluminum fibers 3% were mixed, kneaded by an extruder, cut after extrusion, and made into pellets of synthetic resin B. Using the side injection unit and the primary compound, the primary injection unit and the primary mold form a box-shaped back molded product with a thickness of 3 m/m and external dimensions of 197 x 247 x 28.5 m/m and a boss. After injection molding, cooling, opening the mold, and cutting and removing the direct gate, the resulting molded back surface is attached to the primary fixed mold, and the rotating surface plate is rotated 180° to transfer it to the secondary mold. Colored white by the next injection unit
The outer surface part is injection molded using ABS resin (synthetic resin B), and the outer surface molded body and the back molded body are fused and integrated. External dimensions: 200 x 250 x 30 mm, thickness.
A 4.5 mm box-shaped molded product was obtained. The injection molding conditions were as follows: mold temperature on the primary side was 60°C, injection pressure was 1200 kg/cm 2 , molding temperature was 230°C, and injection time was 2 seconds. In addition, on the secondary side, the mold temperature is 60℃ and the injection pressure is 1000℃.
Kg/cm 2 , molding temperature was 220°C, and injection time was 1.5 seconds. The obtained molded product has a white ABS layer with a thickness of 1.5 m/m on the outer surface and a layer with a thickness of 3 m/m containing a conductive filler on the back surface, and has a good surface without sink marks. In addition to exhibiting smoothness, the back surface also had excellent insulation properties. Furthermore, when the electromagnetic wave shielding properties were measured according to the method of WD Nason et al., it showed a shielding performance of 40 dB at 100 MHz, and there was no risk of electromagnetic interference even when used as a plastic housing for digital electronic equipment. The boundary between the synthetic resin A layer and the synthetic resin B layer was completely fused during injection molding, and there was no problem in terms of strength. Example 2 A beige-colored polystyrene (synthetic resin A) was injection molded using a primary injection unit and a primary mold, with external dimensions of 400 x 300 x 50 mm and a thickness of 1.5 mm.
The mold for molding the box-shaped surface layer part of m/m is in the form of 3 plates, with a pin gate of 2 points,
The gate is now cut off at the same time as the mold opens.
Injection molding conditions are mold temperature 50℃, injection pressure 1000Kg/
cm 2 , molding temperature was 210° C., and injection time was 2 seconds. After opening the mold, the rotating surface plate is rotated 180°, and the molded surface part obtained is replaced with the primary fixed mold and the secondary fixed mold, and after the mold is clamped, the molded product is transferred to the secondary injection unit. Therefore, by injection molding a compound (synthetic resin B) with the following formulation on the back side, the outer dimensions of the front side molded body and the back side molded body are fused and integrated.
A box-shaped molded product with dimensions of 400×300×50 m/m and a thickness of 5 m/m was obtained. Compound in this case (synthetic resin B)
75% polystyrene, 3% brass fiber,
18% aluminum flakes, 4 aluminum fibers
% was kneaded in a single screw extruder, extruded and cut into pellets.The injection molding conditions were: mold temperature 50℃, injection pressure 1100Kg/cm 2 , molding temperature 210℃,
The injection time was 3 seconds. After molding, the gate part was cut and finished. The obtained molded product had a beige-colored surface with no sink marks, a smooth and beautiful appearance, excellent surface insulation, and sufficient electromagnetic wave shielding properties and strength.
第１図は従来の実施例を示す側断面図、第２図
からは、本発明による実施例を示し、第２図は射
出成形装置主要部分を示す側面図、第３図は第２
図の部分垂直断面図、第４図は成形品の断面図で
ある。
図中、１……一次側射出ユニツト、２，５……
ホツパー、３，６……射出シリンダ、４……二次
側射出ユニツト、７……一次側金型、８……一次
側可動金型、９……一次側可動定盤、１０……一
次側固定金型、１１……回転定盤、１２，２１…
…金型キヤビテイ、１３，１９……ダイレクトゲ
ート、１４……二次側金型、１５……二次側可動
金型、１６……二次側可動定盤、１７……二次側
固定金型、１８……金型コア部分、２０……裏面
部成形体、２２……成形品、２３……導電性フイ
ラー、２４……表面部成形体。
FIG. 1 is a side sectional view showing a conventional embodiment, FIG. 2 shows an embodiment according to the present invention, FIG. 2 is a side view showing the main parts of an injection molding apparatus, and FIG.
The figure is a partial vertical sectional view, and FIG. 4 is a sectional view of the molded product. In the figure, 1... primary injection unit, 2, 5...
Hopper, 3, 6... Injection cylinder, 4... Secondary injection unit, 7... Primary side mold, 8... Primary side movable mold, 9... Primary side movable surface plate, 10... Primary side Fixed mold, 11... Rotating surface plate, 12, 21...
...Mold cavity, 13, 19...Direct gate, 14...Secondary side mold, 15...Secondary side movable mold, 16...Secondary side movable surface plate, 17...Secondary side fixed metal Mold, 18... Mold core portion, 20... Back molded product, 22... Molded product, 23... Conductive filler, 24... Surface molded product.
Claims (1)
可塑性合成樹脂を複数段射出成形して多層構造と
し、少なくとも凸部を有する側は容積率10〜25％
の金属充填材を混合した熱可塑性合成樹脂によつ
て射出成形することを特徴とするヒケ防止方法。1. When manufacturing a molded product that has a convex portion on one side, a multilayer structure is obtained by injection molding thermoplastic synthetic resin in multiple stages, and at least the side with the convex portion has a volume ratio of 10 to 25%.
A method for preventing sink marks characterized by injection molding using a thermoplastic synthetic resin mixed with a metal filler.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17006783A JPS6061223A (en) | 1983-09-14 | 1983-09-14 | Shrink mark preventing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17006783A JPS6061223A (en) | 1983-09-14 | 1983-09-14 | Shrink mark preventing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6061223A JPS6061223A (en) | 1985-04-09 |
| JPH0343967B2 true JPH0343967B2 (en) | 1991-07-04 |
Family
ID=15898015
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17006783A Granted JPS6061223A (en) | 1983-09-14 | 1983-09-14 | Shrink mark preventing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6061223A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0180383A3 (en) * | 1984-10-26 | 1987-06-03 | Aronkasei Co., Limited | A manufacturing method for housings with a two-layer structure |
| DE3712959A1 (en) * | 1987-04-02 | 1988-10-20 | Schock & Co Gmbh | TOWEL-PLASTIC PLASTIC SANITATION OBJECT, IN PARTICULAR BATHTUB |
| FR2853275B1 (en) * | 2003-04-04 | 2006-06-09 | Axilone Plastique | PROCESS FOR PRODUCING A RIGID PIECE OF PLASTIC MATERIAL BY RIGID ASSOCIATION OF TWO PARTS OF PIECE |
-
1983
- 1983-09-14 JP JP17006783A patent/JPS6061223A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6061223A (en) | 1985-04-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5642228A (en) | Resin-molded lens having no sink marks and process for producing same | |
| CA2145828A1 (en) | Material and process for manufacturing plastic parts | |
| EP0180383A2 (en) | A manufacturing method for housings with a two-layer structure | |
| JPH0343967B2 (en) | ||
| JPS6025719A (en) | Method of molding sandwich | |
| JP3192341B2 (en) | Insulated tableware and its manufacturing method | |
| JPS6029335B2 (en) | molding mold | |
| JPS58192398A (en) | Electromagnetically shielded molded article | |
| JPH11254476A (en) | Production of resin-sealed molded product of electric/ electronic part | |
| JPS58168300A (en) | Electromagnetic shielded molded part | |
| CN1225774C (en) | Method for manufacturing molded resin piece having surface distributed metal | |
| JP2000000865A (en) | Method for injection molding plastic | |
| JPH066313B2 (en) | Injection nozzle device of injection molding machine | |
| JPS59128704A (en) | Method of producing conductive filler containing molding material | |
| JPH0866936A (en) | Manufacture of resin molded body for electromagnetic wave shield or magnetic shield | |
| JPH0112648B2 (en) | ||
| JPH0861993A (en) | Manufacture of protective cover for gage | |
| JPH09174596A (en) | Production of thick-walled resin molded product and the product | |
| JPS6183013A (en) | Manufacture of conductive resin molded product | |
| JPS591784Y2 (en) | Injection molding machine with sink prevention mechanism | |
| JPS60139416A (en) | Forming of electromagnetic shield | |
| JPH11105082A (en) | Hot runner mold | |
| JP3095335B2 (en) | Injection molding method | |
| JPH05200793A (en) | Mold and manufacture of in-mold transfer board | |
| JPS61293827A (en) | Manufacture of electrically conductive plastic molded body |