JPH0482091B2 - - Google Patents
Info
- Publication number
- JPH0482091B2 JPH0482091B2 JP3496388A JP3496388A JPH0482091B2 JP H0482091 B2 JPH0482091 B2 JP H0482091B2 JP 3496388 A JP3496388 A JP 3496388A JP 3496388 A JP3496388 A JP 3496388A JP H0482091 B2 JPH0482091 B2 JP H0482091B2
- Authority
- JP
- Japan
- Prior art keywords
- sleeve
- layer resin
- flow path
- nozzle
- resin flow
- 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 - Lifetime
Links
- 239000010410 layer Substances 0.000 claims description 96
- 229920005989 resin Polymers 0.000 claims description 87
- 239000011347 resin Substances 0.000 claims description 87
- 238000001746 injection moulding Methods 0.000 claims description 29
- 239000012790 adhesive layer Substances 0.000 claims description 10
- 239000007924 injection Substances 0.000 description 29
- 238000002347 injection Methods 0.000 description 29
- 238000000034 method Methods 0.000 description 4
- 230000004888 barrier function Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 229920001225 polyester resin Polymers 0.000 description 2
- 239000004645 polyester resin Substances 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- OEPOKWHJYJXUGD-UHFFFAOYSA-N 2-(3-phenylmethoxyphenyl)-1,3-thiazole-4-carbaldehyde Chemical compound O=CC1=CSC(C=2C=C(OCC=3C=CC=CC=3)C=CC=2)=N1 OEPOKWHJYJXUGD-UHFFFAOYSA-N 0.000 description 1
- 229920000219 Ethylene vinyl alcohol Polymers 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 230000032798 delamination Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920005672 polyolefin resin Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 125000006839 xylylene group Chemical group 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
- B29C45/1603—Multi-way nozzles specially adapted therefor
- B29C45/1607—Multi-way nozzles specially adapted therefor having at least three different ways
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Description
（産業上の利用分野）
本発明は、多層射出成形用ノズルに関し、より
詳細には、外層、中間層及び内層を備えた多層樹
脂成形体を、中間層を厳密に制御した状態で製造
するための多層射出成形用ノズルに関する。
（従来の技術）
樹脂製容器は、金属製容器やガラス製容器とは
異なり、器壁を通して酸素等のガスの透過を無視
し得ないオーダーで生じ、内容物の保存性に劣つ
ている。この問題を解消するために、衛生的特性
や耐湿性に優れた樹脂を内外層とし、ガスバリヤ
ー性に優れた樹脂を中間層とした多層樹脂容器が
広く使用されている。
この多層樹脂容器の製造法として、射出金型内
に樹脂を多層に共射出して直接多層容器を成形す
る方法や、多層共射出により一旦プリフオームを
製造し、この多層プリフオームを延伸ブロー成形
する方法が知られている。
多層射出成形用ノズルとしては、先端にオリフ
イスを有するノズル外筒内に大径スリーブ及び小
径スリーブを介して同軸に設けられた外層樹脂流
路、中間層樹脂流路及び内層樹脂流路を備えたも
のが使用されており、従来の射出成形用ノズル
は、例えば米国特許第4035466号明細書及び特表
昭56−501040号公報に記載されている通り、中間
層樹脂流路も外層樹脂流路と同様に、その先端部
が先細りのテーパー状となつてオリフイスに向け
て開口したものが使用されている。
（発明が解決すべき問題点）
しかしながら、従来使用されている多層射出成
形用ノズルでは、射出成形物中における中間層の
位置や配置を厳密に制御すること、しばしば困難
であり、例えば中間層が二層以上に分岐したり或
いは分岐した中間層が射出成形物の表面に露出し
たりするという欠点が認められる。中間層が成形
物の表面に露出すると、中間層樹脂の吸湿による
諸特性の低下、特に酸素バリヤー性の低下や、中
間層と内外層との層間剥離、即ちデラミネーシヨ
ンが生ずるようになる。
特に容器の口部や底部に中間層が露出するのを
防止するため、中間層樹脂の射出タイミングと内
外層樹脂の射出タイミングとをずらし、中間層樹
脂の射出開始を内外層樹脂の射出開始よりも遅く
し且つ中間層樹脂の射出終了を内外層樹脂の射出
終了よりも早くすることが行われているが、従来
の多層射出成形用ノズルでは、中間層樹脂の射出
圧を遮断した後でも中間層樹脂が内外層樹脂に随
伴して流出を続け、底部に中間層が露出するとい
う問題を生じる。
従つて、本発明の目的、従来の多層射出成形用
ノズルにおける上記問題点が解消され、射出成形
物中における中間層の位置や配置を厳密に制御し
得る多層射出成形用ノズルを提供するにある。
（問題点を解決するための手段）
本発明によれば、先端にオリフイスを有するノ
ズル外筒内に大径スリーブ及び小径スリーブを介
して同軸に設けられた外層樹脂流路、中間層樹脂
流路及び内層樹脂流路を備えた多層射出成形用ノ
ズルにおいて、大径スリーブの内面及び小径スリ
ーブの外面は、先端に向けて比較的大径の円筒
面、先細りのテーパー面及び比較的小径の円筒面
から形成され、小径スリーブの円状先端面はオリ
フイスより後退した位置に位置し、外層樹脂流
路、中間層樹脂流路及び内層樹脂流路の先端は前
記円状先端面と実質上同じ面に位置していること
を特徴とする多層射出成形用ノズルが提供され
る。
本発明によればまた、大径スリーブが同軸の第
一のスリーブと第二のスリーブとから成り、第一
のスリーブと第二のスリーブとの間に外層側接着
層樹脂流路が設けられ、小径スリーブが同軸の第
一スリーブと第二スリーブとから成り、第一スリ
ーブと第二スリーブとの間に内層側接着層樹脂流
路が設けられ、外層側及び内層側接着層樹脂流路
の先端が前記円状先端面と同じ面に位置している
ことを特徴とする上記多層射出成形用ノズルが提
供される。
（作用）
本発明の多層射出成形用ノズルにおいても、大
径スリーブと小径スリーブとの間に中間層樹脂流
路が形成されるが、大径スリーブの内面及び小径
スリーブの外面を、先端に向けて比較的大径の円
筒面、先細りのテーパー面及び比較的小径の円筒
面から形成し、小径スリーブ先端を円状先端面と
してオリフイスより後退した位置に位置させ、外
層樹脂流路、中間層樹脂流路及び内層樹脂流路の
先端を前記円状先端面と実質上同じ面に位置させ
たことが顕著な特徴である。
即ち、本発明のノズルにおいては、中間層樹脂
流路に先細りのテーパー状流路に続いてストレー
トな円筒状流路（ランド部）があり、中間層樹脂
はテーパー状流路で発生する周方向の圧縮力が十
分に緩和され層流の形でオリフイス後方空間内に
導入される。しかも、本発明のノズルでは外層樹
脂流路、中間層樹脂流路及び内層樹脂流路の各先
端が小径スリーブの円状先端面と実質上同じ面に
位置するように配置したことにより、層流の形で
供給される中間層樹脂流は、外層樹脂流及び内層
樹脂流で直ちにサンドイツチされ、乱流等の乱れ
を生じることなしにオリフイスを通して射出金型
中に射出されることになる。本発明において、小
径スリーブの先端を円状先端面とし、これをオリ
フイスから後退した位置に設けた場合にも、渦の
発生等に基づく乱流を一切生じないことは真に意
外の事実である。これは円状先端面とオリフイス
との間に円錐台状空間があり、外層樹脂流に加え
る周方向の圧縮応力が緩和されることが一因であ
ると思われる。
本発明の多層射出成形用ノズルによると、以上
の作用により、射出成形物中に中間層の分岐や分
離等を発生するのが有効に防止され、しかも中間
層の先端及び後端をも厳密に制御することが可能
となる。
（実施例）
本発明の多層射出成形用ノズルの一例の断面構
造を示す第１図において、このノズル１は、互い
に同軸上に設けられたノズル外筒２、外筒内の大
径スリーブ３及び大径スリーブ内の小径スリーブ
４から成つている。ノズル外筒２は先細りとなつ
ていて、その先端中心にはオリフイス５が設けら
れている。ノズル外筒２と大径スリーブ３との間
には外層樹脂流路６、大径スリーブ３と小径スリ
ーブ４との間には中間層樹脂流路７が夫々設けら
れ、小径スリーブ４の内部には内層樹脂流路８が
設けられている。
ノズル外筒２の内面は、円筒面９及び先細りの
テーパー面１０から成つており、これに対応して
大径スリーブ３の内面も、円筒面１１及び先細り
のテーパー面１２から成つている。
大径スリーブ３の内面は、比較的大径の円筒面
１３、先細りのテーパー面１４及び比較的小径で
軸方向寸法の小さい円筒面１５から成つており、
これに対応して小径スリーブ４の外面も、比較的
大径の円筒面１６、先細りのテーパー面１７及び
比較的小径で軸方向寸法の小さい円筒面１８から
成つている。即ち、本発明のノズルにおける中間
層樹脂流路７は、面１４及び１７で規定される先
細りテーパー上流路に続いて面１５及び１８で規
定されるストレートな樹脂流路（ランド部）があ
ることが特徴である。小径スリーブ４の先端は軸
方向に直角に切断されていて、円状先端面１９と
なつている。
小径スリーブ４の内面にも、比較的大径の円筒
面２０、先細りテーパー面２１及び比較的小径の
円筒面２２で規定される内層樹脂流路８がある。
小径スリーブ４の円状先端面１９はオリフイス
５の先端よりも若干後退した位置にあり、オリフ
イス５と小径スリーブ４との間に円錐台状の小空
間２３が形成される。上記の構造により、外層樹
脂流路６、中間層樹脂流路７及び内層樹脂流路８
を各先端は円状先端面１９と実質上同一の面に位
置していることが了解されよう。
外層樹脂テーパー流路１０−１２のテーパー角
度（θ1、軸からの角度）、中間層樹脂流路１４−
１７のテーパー角度（θ2）、ストレート流路（ラ
ンド）１５−１８の軸方向寸法（ｌ、mm）及び径
（ｄ、mm）は射出成形物の大きさ等によつて異な
るが一般に次の範囲にあるのがよい。
(Industrial Application Field) The present invention relates to a nozzle for multilayer injection molding, and more specifically, for producing a multilayer resin molded article having an outer layer, an intermediate layer, and an inner layer with the intermediate layer strictly controlled. This invention relates to a nozzle for multilayer injection molding. (Prior Art) Unlike metal containers and glass containers, resin containers have a non-negligible amount of permeation of gases such as oxygen through the container walls, and are inferior in storage stability of the contents. In order to solve this problem, multilayer resin containers are widely used in which the inner and outer layers are made of resin with excellent hygienic properties and moisture resistance, and the middle layer is made of resin with excellent gas barrier properties. Methods for manufacturing this multilayer resin container include a method in which resin is co-injected in multiple layers into an injection mold to directly mold the multilayer container, and a method in which a preform is once manufactured by multilayer co-injection and then this multilayer preform is stretch-blow molded. It has been known. The nozzle for multilayer injection molding is equipped with an outer layer resin flow path, an intermediate layer resin flow path, and an inner layer resin flow path provided coaxially through a large diameter sleeve and a small diameter sleeve in a nozzle outer cylinder having an orifice at the tip. In conventional injection molding nozzles, the middle layer resin flow path is also the outer layer resin flow path, as described in U.S. Pat. Similarly, a tip having a tapered tip and opening toward an orifice is used. (Problems to be Solved by the Invention) However, with conventionally used multilayer injection molding nozzles, it is often difficult to strictly control the position and arrangement of the intermediate layer in the injection molded product. Disadvantages are recognized that the method is branched into two or more layers, or that a branched intermediate layer is exposed on the surface of the injection molded product. When the intermediate layer is exposed on the surface of the molded product, the intermediate layer resin absorbs moisture, resulting in deterioration of various properties, particularly oxygen barrier properties, and interlayer separation between the intermediate layer and the inner and outer layers, that is, delamination. In particular, in order to prevent the intermediate layer from being exposed at the mouth and bottom of the container, the injection timing of the intermediate layer resin and the injection timing of the inner and outer layer resins are staggered, and the injection timing of the intermediate layer resin is delayed from the injection timing of the inner and outer layer resins. However, with conventional multilayer injection molding nozzles, even after the injection pressure of the intermediate layer resin is cut off, The layer resin continues to flow out along with the inner and outer layer resins, resulting in a problem that the intermediate layer is exposed at the bottom. Therefore, an object of the present invention is to provide a multilayer injection molding nozzle that solves the above-mentioned problems in conventional multilayer injection molding nozzles and allows for strict control of the position and arrangement of the intermediate layer in the injection molded product. . (Means for solving the problem) According to the present invention, an outer layer resin flow path and an intermediate layer resin flow path are provided coaxially through a large diameter sleeve and a small diameter sleeve in a nozzle outer cylinder having an orifice at the tip. and a multilayer injection molding nozzle equipped with an inner resin flow path, the inner surface of the large-diameter sleeve and the outer surface of the small-diameter sleeve have a cylindrical surface with a relatively large diameter, a tapered surface, and a cylindrical surface with a relatively small diameter toward the tip. The circular tip surface of the small-diameter sleeve is located at a position set back from the orifice, and the tips of the outer layer resin flow path, the middle layer resin flow path, and the inner layer resin flow path are substantially in the same plane as the circular tip surface. A multilayer injection molding nozzle is provided, characterized in that the nozzle is located at the top of the injector. According to the present invention, the large-diameter sleeve is composed of a coaxial first sleeve and a second sleeve, and an outer adhesive layer resin flow path is provided between the first sleeve and the second sleeve, The small-diameter sleeve consists of a coaxial first sleeve and a second sleeve, and an inner adhesive layer resin channel is provided between the first sleeve and the second sleeve, and the tips of the outer and inner adhesive layer resin channels are provided. The multilayer injection molding nozzle is provided, wherein the nozzle is located on the same surface as the circular tip surface. (Function) Also in the multilayer injection molding nozzle of the present invention, an intermediate layer resin flow path is formed between the large diameter sleeve and the small diameter sleeve, but the inner surface of the large diameter sleeve and the outer surface of the small diameter sleeve are directed toward the tip. The sleeve is formed of a relatively large diameter cylindrical surface, a tapered tapered surface, and a relatively small diameter cylindrical surface, and the small diameter sleeve tip is positioned as a circular tip surface at a position recessed from the orifice, and the outer layer resin flow path and the middle layer resin A remarkable feature is that the tips of the flow path and the inner layer resin flow path are located on substantially the same plane as the circular tip surface. That is, in the nozzle of the present invention, the intermediate layer resin flow path has a tapered flow path followed by a straight cylindrical flow path (land portion), and the intermediate layer resin flows in the circumferential direction generated in the tapered flow path. The compressive force is sufficiently relaxed and introduced into the space behind the orifice in the form of a laminar flow. Moreover, in the nozzle of the present invention, the tips of the outer layer resin flow path, the intermediate layer resin flow path, and the inner layer resin flow path are arranged so that they are located on substantially the same plane as the circular tip surface of the small diameter sleeve, so that laminar flow can be achieved. The middle layer resin flow supplied in the form of is immediately sandwiched between the outer layer resin flow and the inner layer resin flow, and is injected into the injection mold through the orifice without causing any disturbance such as turbulence. In the present invention, it is a truly surprising fact that even when the small-diameter sleeve has a circular tip end face and is placed at a position retreating from the orifice, no turbulent flow due to the generation of vortices occurs. . One reason for this seems to be that there is a truncated conical space between the circular tip surface and the orifice, which relieves the compressive stress in the circumferential direction that is applied to the outer layer resin flow. According to the multilayer injection molding nozzle of the present invention, due to the above-described effects, branching or separation of the intermediate layer in the injection molded product can be effectively prevented, and the leading and trailing ends of the intermediate layer can also be strictly controlled. It becomes possible to control. (Example) In FIG. 1 showing a cross-sectional structure of an example of a nozzle for multilayer injection molding of the present invention, this nozzle 1 includes a nozzle outer cylinder 2, a large-diameter sleeve 3 inside the outer cylinder, and a nozzle outer cylinder 2 provided coaxially with each other. It consists of a small diameter sleeve 4 within a large diameter sleeve. The nozzle outer cylinder 2 is tapered, and an orifice 5 is provided at the center of its tip. An outer layer resin flow path 6 is provided between the nozzle outer cylinder 2 and the large diameter sleeve 3, and an intermediate layer resin flow path 7 is provided between the large diameter sleeve 3 and the small diameter sleeve 4. An inner layer resin flow path 8 is provided. The inner surface of the nozzle outer cylinder 2 consists of a cylindrical surface 9 and a tapered surface 10, and correspondingly, the inner surface of the large diameter sleeve 3 also consists of a cylindrical surface 11 and a tapered surface 12. The inner surface of the large-diameter sleeve 3 is composed of a cylindrical surface 13 with a relatively large diameter, a tapered surface 14, and a cylindrical surface 15 with a relatively small diameter and small axial dimension.
Correspondingly, the outer surface of the small-diameter sleeve 4 also consists of a cylindrical surface 16 with a relatively large diameter, a tapered surface 17, and a cylindrical surface 18 with a relatively small diameter and small axial dimension. That is, the intermediate layer resin flow path 7 in the nozzle of the present invention has a tapered upstream path defined by surfaces 14 and 17, followed by a straight resin flow path (land portion) defined by surfaces 15 and 18. is a feature. The tip of the small diameter sleeve 4 is cut at right angles to the axial direction to form a circular tip surface 19. The inner surface of the small-diameter sleeve 4 also has an inner layer resin flow path 8 defined by a relatively large-diameter cylindrical surface 20, a tapered surface 21, and a relatively small-diameter cylindrical surface 22. The circular tip surface 19 of the small diameter sleeve 4 is located at a position slightly recessed from the tip of the orifice 5, and a truncated conical small space 23 is formed between the orifice 5 and the small diameter sleeve 4. With the above structure, the outer layer resin flow path 6, the intermediate layer resin flow path 7, and the inner layer resin flow path 8
It will be appreciated that each tip lies in substantially the same plane as the circular tip surface 19. Taper angle (θ 1 , angle from axis) of outer layer resin taper flow path 10-12, middle layer resin flow path 14-
The taper angle (θ 2 ) of No. 17, the axial dimension (l, mm) and diameter (d, mm) of the straight flow path (land) 15-18 vary depending on the size of the injection molded product, etc., but are generally as follows. It's good to be within range.
【表】
本発明の多層射出成形用ノズルを用いた射出成
形装置の概略配置を示す第２図において、この装
置は、ノズル１、ホツトランナーブロツク５０、
射出金型５１、外装及び内層樹脂射出機５２及び
中間層樹脂射出機５３から成る。ホツトランナー
ブロツク５０には、中心に内層樹脂用中実流路５
４があり、その周囲に環状の中間層樹脂用内環状
流路５５及び更にその外周に外層樹脂用外環状流
路５６が位置しており、これら各流路はホツトラ
ンナーノズル１の各樹脂流路に接続されている。
また、内外層用射出機５２は分岐チヤンネル５７
及び５８を介して対応流路５４及び５６に接続さ
れ、中間層用射出機５３はノズル５９を介して中
間層用流路５５に接続される。射出機５２及び５
３にはそれぞれスクリユー６１及び６２が設けら
れている。
射出金型５１はキヤビテイ型６３とコア型６４
とから成り、両者の間にキヤビテイ６５が設けら
れている。キヤビテイ型６３には、キヤビテイ６
５に通じるゲート６６が設けられており、型締し
た状態で、ノズル１のオリフイス５、ゲート６６
及びキヤビテイ６５が連通するようになつてい
る。
樹脂の射出成形に際しては、内外層用射出機５
２のスクリユー６１を前進させ、或る量の内外層
用樹脂の射出を開始させる。これより若干のタイ
ミングを遅らせて中間層用射出機５３のスクリユ
ー６２を前進させ中間層樹脂を内外層と併進的に
射出する。射出の終期に近づいて、中間層樹脂射
出機５３のスクリユー６２を停止し、中間層樹脂
の射出を停止する。この停止後も内外層樹脂の射
出を若干続けた後、内外層樹脂射出機５２のスク
リユー６１を停止し、射出成形サイクルが終了す
る。
内外層樹脂としては、ポリエチレン、ポリプロ
ピレン等のオレフイン樹脂、スチレン系樹脂、ポ
リエステル樹脂等が使用され、中間層樹脂として
は、エチレン−ビニルアルコール共重合体、塩化
ビニリデン系樹脂、キシリレン基含有ポリアミ
ド、ガスバリヤー性ポリエステル樹脂等が使用さ
れる。
本発明の装置は、３層よりも多い多層樹脂射出
成形にも適用できる。例えば、第３図に示す多層
射出成形用ノズルにおいては、大径スリーブが同
軸の第一のスリーブ３ａと第二のスリーブ３ｂと
から成り、第一のスリーブ３ａと第二のスリーブ
３ｂとの間に外層側接着層樹脂流路２４が設けら
れ、小径スリーブが同軸の第一スリーブ４ａと第
二スリーブ４ｂとから成り、第一スリーブ４ａと
第二スリーブ４ｂとの間に内層側接着層樹脂流路
２５が設けられ、外層側及び内層側接着層樹脂流
路の先端も前記円状先端面１９と同じ面に位置し
ている。
（発明の効果）
本発明の多層射出成形用ノズルによれば、中間
層に乱流を発生することなしに、層流の形で内外
層樹脂にサンドイツチさせることが可能となつ
た。
本発明の多層射出成形用ノズルによると、以上
の効果により、射出成形物中に中間層の分岐や分
離等が発生するのが有効に防止され、しかも中間
層の先端及び後端をも厳密に制御することが可能
となる。[Table] In FIG. 2 showing the schematic arrangement of an injection molding apparatus using the multilayer injection molding nozzle of the present invention, this apparatus includes a nozzle 1, a hot runner block 50,
It consists of an injection mold 51, an exterior and inner layer resin injection machine 52, and an intermediate layer resin injection machine 53. The hot runner block 50 has a solid channel 5 for inner layer resin in the center.
4, around which an annular inner annular channel 55 for the intermediate layer resin and an outer annular channel 56 for the outer layer resin are located on the outer periphery of the inner annular channel 55. connected to the road.
In addition, the injection machine 52 for the inner and outer layers has a branch channel 57.
and 58 to the corresponding channels 54 and 56, and the intermediate layer injection machine 53 is connected to the intermediate layer channel 55 via a nozzle 59. Injection machines 52 and 5
3 are provided with screws 61 and 62, respectively. The injection mold 51 has a cavity mold 63 and a core mold 64.
A cavity 65 is provided between the two. Cavity type 63 has cavity 6.
A gate 66 leading to the orifice 5 of the nozzle 1 and the gate 66 are provided when the mold is closed.
and cavity 65 are arranged to communicate with each other. When injection molding resin, injection machine 5 for inner and outer layers is used.
The second screw 61 is advanced to start injection of a certain amount of resin for the inner and outer layers. The screw 62 of the intermediate layer injection machine 53 is moved forward with a slight delay from this timing, and the intermediate layer resin is injected in parallel with the inner and outer layers. Nearing the end of the injection, the screw 62 of the intermediate layer resin injection machine 53 is stopped, and the injection of the intermediate layer resin is stopped. After this stoppage, the injection of the inner and outer layer resin continues for a while, and then the screw 61 of the inner and outer layer resin injection machine 52 is stopped, and the injection molding cycle is completed. As the inner and outer layer resins, olefin resins such as polyethylene and polypropylene, styrene resins, polyester resins, etc. are used, and as the intermediate layer resins, ethylene-vinyl alcohol copolymers, vinylidene chloride resins, xylylene group-containing polyamides, and gases are used. Barrier polyester resin etc. are used. The apparatus of the invention can also be applied to multilayer resin injection molding with more than three layers. For example, in the multilayer injection molding nozzle shown in FIG. 3, the large-diameter sleeve consists of a coaxial first sleeve 3a and a second sleeve 3b, and a An outer adhesive layer resin flow path 24 is provided in the outer layer side adhesive layer resin flow path 24, the small diameter sleeve is composed of a coaxial first sleeve 4a and a second sleeve 4b, and an inner layer side adhesive layer resin flow path 24 is provided between the first sleeve 4a and the second sleeve 4b. A channel 25 is provided, and the tips of the outer layer side and inner layer side adhesive layer resin flow channels are also located on the same plane as the circular tip surface 19. (Effects of the Invention) According to the multilayer injection molding nozzle of the present invention, it has become possible to sandwich the inner and outer layer resins in a laminar flow without generating turbulence in the intermediate layer. According to the multilayer injection molding nozzle of the present invention, due to the above-mentioned effects, it is possible to effectively prevent the occurrence of branching or separation of the intermediate layer in the injection molded product, and also to strictly control the leading and trailing ends of the intermediate layer. It becomes possible to control.
第１図は、本発明の多層射出成形用ノズルの断
面図であり、第２図は、このノズルを設けた射出
成形装置の概略配置図であり、第３図は、本発明
の多層射出成形用ノズルの他の例の断面図であ
る。
１はノズル、２はノズル外筒、３は大径スリー
ブ、４は小径スリーブ、５はオリフイス、６は多
層樹脂流路、７は中間層樹脂流路、８は内層樹脂
流路、１４及び１７は先細りテーパー面、１５及
び１８は比較的小径の円筒面、１９は小径スリー
ブの円状先端面、２３は円錐台状空間である。
FIG. 1 is a sectional view of a multilayer injection molding nozzle of the present invention, FIG. 2 is a schematic layout diagram of an injection molding apparatus equipped with this nozzle, and FIG. 3 is a cross-sectional view of a multilayer injection molding nozzle of the present invention. It is a sectional view of another example of the nozzle for use. 1 is a nozzle, 2 is a nozzle outer cylinder, 3 is a large diameter sleeve, 4 is a small diameter sleeve, 5 is an orifice, 6 is a multilayer resin flow path, 7 is an intermediate layer resin flow path, 8 is an inner layer resin flow path, 14 and 17 15 and 18 are relatively small-diameter cylindrical surfaces, 19 is a circular tip surface of the small-diameter sleeve, and 23 is a truncated conical space.
Claims (1)
径スリーブ及び小径スリーブを介して同軸に設け
られた外層樹脂流路、中間層樹脂流路及び内層樹
脂流路を備えた多層射出成形用ノズルにおいて、 大径スリーブの内面及び小径スリーブの外面
は、先端に向けて比較的大径の円筒面、先細りの
テーパー面及び比較的小径の円筒面から形成さ
れ、小径スリーブの円状先端面はオリフイスより
後退した位置に位置し、外層樹脂流路、中間層樹
脂流路及び内層樹脂流路の先端は前記円状先端面
と実質上同じ面に位置していることを特徴とする
多層射出成形用ノズル。 ２ 小径スリーブの円状先端面とオリフイスとの
間に円錐台状空間が設けられている請求項第１項
記載の多層射出成形用ノズル。 ３ 大径スリーブが同軸の第一のスリーブと第二
のスリーブとから成り、第一のスリーブと第二の
スリーブとの間に外層側接着層樹脂流路が設けら
れ、小径スリーブが同軸の第一スリーブと第二ス
リーブとから成り、第一スリーブと第二スリーブ
との間に内層側接着層樹脂流路が設けられ、外層
側及び内層側接着層樹脂流路の先端が前記円状先
端面と同じ面に位置していることを特徴とする請
求項第１項記載の多層射出成形用ノズル。[Claims] 1. A multi-layered nozzle having an orifice at its tip, which has an outer layer resin flow path, an intermediate layer resin flow path, and an inner layer resin flow path provided coaxially through a large-diameter sleeve and a small-diameter sleeve within a nozzle outer cylinder. In an injection molding nozzle, the inner surface of the large-diameter sleeve and the outer surface of the small-diameter sleeve are formed of a cylindrical surface with a relatively large diameter, a tapered surface, and a cylindrical surface with a relatively small diameter toward the tip. The tip surface is located at a position retreating from the orifice, and the tips of the outer layer resin flow path, the middle layer resin flow path, and the inner layer resin flow path are located on substantially the same plane as the circular tip surface. Nozzle for multilayer injection molding. 2. The multilayer injection molding nozzle according to claim 1, wherein a truncated conical space is provided between the circular tip surface of the small diameter sleeve and the orifice. 3. The large-diameter sleeve consists of a coaxial first sleeve and a second sleeve, an outer adhesive layer resin channel is provided between the first sleeve and the second sleeve, and a small-diameter sleeve consists of a coaxial first sleeve and a second coaxial sleeve. It consists of a first sleeve and a second sleeve, and an inner adhesive layer resin channel is provided between the first sleeve and the second sleeve, and the tips of the outer layer side and inner layer side adhesive layer resin channel are shaped like the circular tip surface. 2. The multilayer injection molding nozzle according to claim 1, wherein the nozzle is located on the same plane as the nozzle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3496388A JPH01210320A (en) | 1988-02-19 | 1988-02-19 | Nozzle for multi-layer injection molding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3496388A JPH01210320A (en) | 1988-02-19 | 1988-02-19 | Nozzle for multi-layer injection molding |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01210320A JPH01210320A (en) | 1989-08-23 |
| JPH0482091B2 true JPH0482091B2 (en) | 1992-12-25 |
Family
ID=12428800
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3496388A Granted JPH01210320A (en) | 1988-02-19 | 1988-02-19 | Nozzle for multi-layer injection molding |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01210320A (en) |
-
1988
- 1988-02-19 JP JP3496388A patent/JPH01210320A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01210320A (en) | 1989-08-23 |
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