JPH07148766A - Hollow injection molding method and mold - Google Patents
Hollow injection molding method and moldInfo
- Publication number
- JPH07148766A JPH07148766A JP32335493A JP32335493A JPH07148766A JP H07148766 A JPH07148766 A JP H07148766A JP 32335493 A JP32335493 A JP 32335493A JP 32335493 A JP32335493 A JP 32335493A JP H07148766 A JPH07148766 A JP H07148766A
- Authority
- JP
- Japan
- Prior art keywords
- thick
- mold
- resin
- hollow
- thick 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.)
- Withdrawn
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
- B29C45/26—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
-
- 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)
- Blow-Moulding Or Thermoforming 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中空部を形成する中空射
出成形方法及びそれに用いる金型に関する。更に詳しく
は、例えば補強用リブやボス等の部分的な厚肉部を有す
る成形品の中空射出成形方法及びそれに用いる金型に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow injection molding for forming a hollow portion by pressurizing a pressurized fluid into a molten resin injected into a mold cavity and discharging the pressurized fluid after necessary cooling. The present invention relates to a method and a mold used for the method. More specifically, for example, the present invention relates to a hollow injection molding method for a molded product having a partially thick portion such as a reinforcing rib and a boss, and a mold used for the method.
【０００２】[0002]
【従来の技術】従来、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て中空部を形成する中空射出
成形方法が知られている（特公昭５７−１４９６８号公
報、特公昭４８−４１２６４号公報）。この中空射出成
形方法によると、部分的に厚肉部を有する成形品の成形
に際し、厚肉部に中空部を形成することで、厚肉部の形
成側とは反対側でかつ厚肉部の形成位置に対応する面
（以下「厚肉部対応面」という）に極端なひけが発生す
るのを防止できる。2. Description of the Related Art Heretofore, there has been known a hollow injection molding method in which a pressurized fluid is pressed into molten resin injected into a mold cavity to form a hollow portion (Japanese Patent Publication No. 57-14968). 48-41264). According to this hollow injection molding method, by forming a hollow portion in the thick portion when forming a molded product having a thick portion, the thick portion is formed on the opposite side to the thick portion. It is possible to prevent the occurrence of extreme sink marks on the surface corresponding to the formation position (hereinafter referred to as the “thick-wall portion corresponding surface”).
【０００３】一方、射出成形品の表面外観を向上させる
ために、金型キャビティ面に断熱材を被覆しておくこと
が知られている（特開平５−１１６１９０号公報）。こ
の断熱材を被覆した金型で射出成形を行うと、得られる
成形品表面の光沢を向上させることができる。On the other hand, in order to improve the surface appearance of the injection-molded article, it is known to coat the mold cavity surface with a heat insulating material (Japanese Patent Laid-Open No. 5-116190). When injection molding is performed using a mold coated with this heat insulating material, the gloss of the surface of the obtained molded product can be improved.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、部分的
に厚肉部を有する成形品を中空射出成形方法で成形し、
当該部分的な厚肉部に中空部を形成すると、厚肉部対応
面に光沢のある筋状部を生じ、その周辺部分との間に光
沢差を生じて外観不良となりやすい問題がある。特に厚
肉部対応面側が製品衣装面であることが多く、塗装やメ
ッキ等の二次加工でこの不良を覆い隠すことが必要とな
って、コスト高の原因となる。However, a molded article partially having a thick portion is molded by the hollow injection molding method,
When the hollow portion is formed in the partial thick portion, a glossy streak portion is formed on the surface corresponding to the thick portion, and there is a problem that a gloss difference is generated between the thick portion and a peripheral portion thereof, and a poor appearance is likely to occur. In particular, the surface corresponding to the thick portion is often the product costume surface, and it is necessary to cover up this defect by secondary processing such as painting or plating, which causes a cost increase.
【０００５】上記光沢差の発生防止のために、金型キャ
ビティ面を断熱材で被覆した金型を用い、成形品全面の
光沢を向上させ、厚肉部対応面とその周辺部分間の光沢
差をなくしてしまうことが考えられる。In order to prevent the above-mentioned gloss difference from occurring, a mold in which the mold cavity surface is covered with a heat insulating material is used to improve the gloss of the entire surface of the molded product, and the gloss difference between the thick portion corresponding surface and the peripheral portion thereof is improved. Can be lost.
【０００６】しかしながら、少なくとも成形品の衣装面
となる側の金型キャビティ面全面に断熱材を被覆しなけ
ればならず、大型の成形品や複雑な表面形状の成形品に
ついては、断熱材を入り組んだ形状に沿って被覆したり
広い範囲に亙って被覆しなければならず、被覆に要する
負担が大きくなる。従って、設備的な原因によるコスト
高を生じる原因となる。However, at least the entire surface of the mold cavity on the side which becomes the costume surface of the molded product must be covered with a heat insulating material, and for a large molded product or a molded product having a complicated surface shape, a heat insulating material is incorporated. Since it is necessary to coat along an elliptical shape or to coat over a wide area, the burden required for coating increases. Therefore, it causes a cost increase due to a facility reason.
【０００７】本発明は、上記問題点に鑑みてなされたも
ので、部分的な厚肉部を有する成形品の中空射出成形に
おいて、厚肉部対応面とその周辺部分間に生じる光沢の
むらを簡便かつ実用性に富んだ金型によって防止するこ
とを目的とする。The present invention has been made in view of the above problems, and in the hollow injection molding of a molded article having a partially thick portion, uneven glossiness between the thick portion corresponding surface and its peripheral portion can be easily performed. In addition, the purpose is to prevent by using a mold that is highly practical.
【０００８】[0008]
【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に示されるように、部分的な厚肉
部１を有する成形品の厚肉部１に中空部２を形成する中
空射出成形において、厚肉部１の付け根付近の樹脂の冷
却をその周辺の樹脂の冷却より遅延させることとしてい
るものである。For this reason, in the invention of claim 1, as shown in FIG. 1, a hollow portion 2 is formed in a thick portion 1 of a molded article having a partial thick portion 1. In the hollow injection molding to be formed, the cooling of the resin near the base of the thick portion 1 is delayed from the cooling of the resin around it.
【０００９】また、請求項２及び３の発明では、図１及
び図２に示されるように、部分的な厚肉部１を有する成
形品の厚肉部１に中空部２を形成する中空射出成形に用
いる金型３において、厚肉部１の付け根付近に相当する
箇所に、断熱材４ａ又は金型３との間に断熱層を介在さ
せた蓄熱材４ｂが設けられている金型３としているもの
である。According to the second and third aspects of the present invention, as shown in FIGS. 1 and 2, a hollow injection forming a hollow portion 2 in a thick portion 1 of a molded article having a partial thick portion 1 As a mold 3 in which a heat storage material 4a or a heat storage material 4b with a heat insulating layer interposed between the heat storage material 4a and the mold 3 is provided in a portion corresponding to the vicinity of the base of the thick portion 1 in the mold 3 used for molding There is something.
【００１０】更に本発明を説明する。The present invention will be further described.
【００１１】図１は本発明による成形品の一例を示す断
面図で、図２はこの成形品を成形するための金型３回り
を示す図である。FIG. 1 is a sectional view showing an example of a molded product according to the present invention, and FIG. 2 is a view showing a die 3 for molding the molded product.
【００１２】本発明で成形する成形品は、図１に示され
るように、部分的な厚肉部１を有し、しかも当該厚肉部
１が中空部２を有する成形品である。As shown in FIG. 1, the molded product molded by the present invention is a molded product having a partial thick portion 1 and the thick portion 1 having a hollow portion 2.
【００１３】上記部分的な厚肉部１としては、例えば図
示されるような補強用リブのほかに、ボスや圧力伝達チ
ャンネルを挙げることができる。圧力伝達チャンネルと
は、中空射出成形法において、金型キャビティ５内の溶
融樹脂中に圧入される加圧流体の流れを導くと共に、加
圧流体の圧入位置から離れた位置まで加圧流体を圧入し
やすくするために設けられるリブ状の厚肉部をいう。Examples of the partial thick portion 1 include a boss and a pressure transmission channel in addition to the reinforcing rib as shown in the figure. In the hollow injection molding method, the pressure transmission channel guides the flow of the pressurized fluid that is press-fitted into the molten resin in the mold cavity 5, and pressurizes the pressurized fluid to a position away from the press-fitted position of the pressurized fluid. A rib-shaped thick wall portion provided to facilitate the process.
【００１４】厚肉部１は、１箇所でも複数箇所でもよ
く、独立したものでも連なったものでもよい。また、本
発明は、厚肉部１の幅をｂ、厚肉部１の周辺における厚
肉部１以外の箇所の厚みをａとした時に、ｂ／ａ≧２と
なる厚肉部１である場合に特に有効である。即ち、この
ような厚肉部１の場合、厚肉部対応面７が、その周辺部
と光沢が相違したものとなりやすいことから、その防止
に本発明が有効である。The thick portion 1 may be provided at one location or at a plurality of locations, and may be independent or continuous. Further, the present invention is the thick-walled portion 1 where b / a ≧ 2, where b is the width of the thick-walled portion 1 and a is the thickness of the portion other than the thick-walled portion 1 around the thick-walled portion 1. This is especially effective in the case. That is, in the case of such a thick portion 1, the thick portion corresponding surface 7 is likely to have a gloss different from that of the peripheral portion thereof, and the present invention is effective in preventing this.
【００１５】本発明で成形する成形品の具体例として
は、例えば自動車のインパネ、バンパー、ＯＡ機器や家
電製品のハウジング等を挙げることができる。Specific examples of the molded product molded according to the present invention include an instrument panel of an automobile, a bumper, an office automation equipment and a housing of home electric appliances.
【００１６】上記成形品を成形するための金型３として
は、図２に示されるように、型キャビティ５の壁面の所
定の位置に断熱材４ａ又は蓄熱材４ｂが設けられている
ものを用いる。As the mold 3 for molding the above-mentioned molded product, as shown in FIG. 2, a mold in which a heat insulating material 4a or a heat storage material 4b is provided at a predetermined position on the wall surface of the mold cavity 5 is used. .
【００１７】金型３について更に説明する。The mold 3 will be further described.
【００１８】金型３は、固定型３ａと移動型３ｂとで構
成され、移動型３ｂは固定型３ａに対して進退可能であ
る。The mold 3 is composed of a fixed mold 3a and a movable mold 3b, and the movable mold 3b can move back and forth with respect to the fixed mold 3a.
【００１９】移動型３ｂ側は、図１に示される厚肉部１
に相当する凹部６が形成されており、凹部６の開口部
際、即ち厚肉部１の付け根付近に相当する位置に沿っ
て、断熱材４ａ又は蓄熱材４ｂが延在している。The movable die 3b side is provided with a thick portion 1 shown in FIG.
The heat insulating material 4a or the heat storage material 4b extends along the opening of the recess 6, that is, along the position corresponding to the vicinity of the root of the thick portion 1.
【００２０】断熱材４ａは、金型キャビティ５に射出さ
れた樹脂の熱が金型３に伝わりにくくするもので、金型
３の構成材料よりも熱伝導率が低く、溶融樹脂の成形時
の温度並びに成形品取り出し時の摺動に耐えるもので構
成される。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、ガ
ラス等を用いることができる。The heat insulating material 4a is for making it difficult for the heat of the resin injected into the mold cavity 5 to be transferred to the mold 3. The heat insulating material 4a has a lower thermal conductivity than that of the constituent material of the mold 3 and is used when molding the molten resin. It is configured to withstand temperature and sliding when taking out a molded product. For example, polyimide, epoxy resin, silicone resin, tetrafluoroethylene resin, ceramic, glass or the like can be used.
【００２１】蓄熱材４ｂは、金型キャビティ５に射出さ
れた樹脂の熱を蓄えるもので、金型３との間に断熱層が
介在した状態で設置されている。例えば蓄熱材４ｂを金
型キャビティ５の壁部に嵌め込み設置すると、蓄熱材４
ｂと金型３間に残されるわずかな隙間内の空気層が断熱
層となり、金型キャビティ５に射出された樹脂の熱は蓄
熱材４ｂには伝わるが、蓄熱材４ｂから金型３には逃げ
にくいために蓄積されることになる。但し、このわずか
な隙間は、溶融樹脂が入り込まないことが必要である。
例えば、使用樹脂がポリエチレンの場合、２０μｍ以下
の幅であることが好ましい。The heat storage material 4b stores the heat of the resin injected into the mold cavity 5, and is installed with a heat insulating layer interposed between it and the mold 3. For example, when the heat storage material 4b is fitted and installed in the wall of the mold cavity 5, the heat storage material 4b
The air layer in the slight gap left between b and the mold 3 serves as a heat insulating layer, and the heat of the resin injected into the mold cavity 5 is transmitted to the heat storage material 4b, but from the heat storage material 4b to the mold 3. It will be accumulated because it is hard to escape. However, it is necessary that the molten resin does not enter this slight gap.
For example, when the resin used is polyethylene, the width is preferably 20 μm or less.
【００２２】上記蓄熱材４ｂとしては、ことさら金型３
の構成材料より熱伝導率の低いものを使用する必要はな
く、金型３の構成材料と同じ材料もしくは金型３の構成
材料より熱伝導率の高いものでもよい。例えば、炭素鋼
材、合金工具鋼鋼材（主として熱間金型用ＳＫＤ、冷間
金型用ＳＫＳ、ＳＫＤ）、熱間圧延ステンレス鋼板（主
としてマルテンサイト系ＳＵＳ及び析出硬化系ＳＵ
Ｓ）、高速度工具鋼材（ＳＫＨ）、クロムモリブデン鋼
鋼材（ＳＣＭ）、ニッケルクロムモリブテン鋼鋼材（Ｓ
ＮＣＭ）、炭素工具鋼鋼材（ＳＫ）等の鉄鋼材料、アル
ミ合金、析出硬化形銅合金、ベリリウム銅合金、亜鉛合
金等の非鉄金属やプラスチックを用いることができる。As the heat storage material 4b, the metal mold 3 is used.
It is not necessary to use a material having a lower thermal conductivity than that of the constituent material, and the same material as the constituent material of the mold 3 or a material having a higher thermal conductivity than the constituent material of the mold 3 may be used. For example, carbon steel materials, alloy tool steel materials (mainly hot mold SKD, cold mold SKS, SKD), hot rolled stainless steel plates (mainly martensitic SUS and precipitation hardening SU).
S), high speed tool steel (SKH), chrome molybdenum steel (SCM), nickel chrome molybdenum steel (S)
Steel materials such as NCM) and carbon tool steel (SK), non-ferrous metals such as aluminum alloys, precipitation hardening copper alloys, beryllium copper alloys, zinc alloys and plastics can be used.
【００２３】断熱材４ａ又は蓄熱材４ｂを設ける金型キ
ャビティ５の壁面方向の位置は、凹部６の開口部際であ
れば、図３に示されるように凹部６と接して設けても、
図４に示されるように凹部６に近接して設けてもよい。The position of the heat insulating material 4a or the heat storage material 4b in the wall surface direction of the mold cavity 5 may be provided in contact with the recess 6 as shown in FIG.
It may be provided close to the recess 6 as shown in FIG.
【００２４】また、図３及び図４に示される断熱材４ａ
又は蓄熱材４ｂは凹部６の深さに比して薄くなっている
が、さらに厚肉のものとすることもできる。例えば、図
５に示されるように、凹部６の深さと同じ厚みとし、凹
部６の側壁全体を断熱材４ａ又は蓄熱材４ｂで構成した
り、図６に示されるように、凹部６より厚い断熱材４ａ
又は蓄熱材４ｂとし、この断熱材４ａ又は蓄熱材４ｂに
凹部６を形成して、凹部６全体を断熱材４ａ又は蓄熱材
４ｂで囲むこともできる。The heat insulating material 4a shown in FIGS. 3 and 4 is also used.
Alternatively, the heat storage material 4b is thinner than the depth of the recess 6, but it may be thicker. For example, as shown in FIG. 5, the thickness of the recess 6 is the same as that of the recess 6, and the entire sidewall of the recess 6 is made of the heat insulating material 4a or the heat storage material 4b. As shown in FIG. Material 4a
Alternatively, the heat storage material 4b may be used, and the recess 6 may be formed in the heat insulation material 4a or the heat storage material 4b, and the entire recess 6 may be surrounded by the heat insulation material 4a or the heat storage material 4b.
【００２５】厚肉部１が補強用リブ等の連続したもので
ある場合、断熱材４ａ又は蓄熱材４ｂは、厚肉部１の片
側の付け根付近に相当する箇所に設けたり、多少断続す
るものとすることもできるが、厚肉部１の両側の付け根
部付近相当する箇所に連続して設けることが好ましい。
また、厚肉部１がボス等の独立した柱状のものである場
合、断熱材４ａ又は蓄熱材４ｂは、厚肉部１の付け根付
近に相当する箇所に、厚肉部１を環状に囲んで設けるこ
とが好ましい。In the case where the thick portion 1 is a continuous reinforcing rib or the like, the heat insulating material 4a or the heat storage material 4b is provided at a position corresponding to the vicinity of the root on one side of the thick portion 1 or is somewhat interrupted. However, it is preferable that the thick portions 1 are continuously provided at positions corresponding to the vicinity of the root portions on both sides.
When the thick portion 1 is an independent columnar member such as a boss, the heat insulating material 4a or the heat storage material 4b surrounds the thick portion 1 in an annular shape at a position corresponding to the vicinity of the root of the thick portion 1. It is preferable to provide.
【００２６】断熱材４ａ又は蓄熱材４ｂの幅は、成形品
の形状（厚肉部１の幅ｂ、厚肉部１の周辺における厚肉
部１以外の箇所の厚みａ）並びに成形条件（金型温度、
加圧流体圧入条件、使用樹脂の種類）等により適宜選択
されるが、一般には、断熱材４ａ又は蓄熱材４ｂの取付
性も考慮すると、厚肉部１の幅ｂに対して１×ｂ〜３×
ｂの幅であることが好ましい。幅が狭過ぎると断熱材４
ａ又は蓄熱材４ｂを設けた効果が得にくく、また過剰に
広くしても、断熱材４ａ又は蓄熱材４ｂの設置に要する
手間が増大するだけで大きな効果の向上は望めない。The width of the heat insulating material 4a or the heat storage material 4b is determined by the shape of the molded product (width b of the thick portion 1, thickness a at a portion other than the thick portion 1 around the thick portion 1) and molding conditions (gold). Mold temperature,
It is appropriately selected depending on the pressurizing fluid press-fitting condition, the type of resin used, etc., but in general, considering the attachment of the heat insulating material 4a or the heat storage material 4b, 1 × b to the width b of the thick portion 1 3x
The width is preferably b. If the width is too narrow, insulation 4
It is difficult to obtain the effect of providing the heat storage material 4a or the heat storage material 4b, and even if the heat storage material 4b is excessively widened, the labor required to install the heat insulation material 4a or the heat storage material 4b is increased, and a significant improvement cannot be expected.
【００２７】上述のような断熱材４ａ又は蓄熱材４ｂを
設けた場合に、図１に示される厚肉部対応面７とその周
辺部間に光沢差を生じないのは次のような理由によると
考えられる。When the heat insulating material 4a or the heat storage material 4b as described above is provided, the difference in gloss does not occur between the thick portion corresponding surface 7 shown in FIG. 1 and its peripheral portion for the following reason. it is conceivable that.
【００２８】まず、断熱材４ａ又は蓄熱材４ｂがない場
合、厚肉部１部分は冷却が遅れがちで、中空部２内の加
圧流体の圧力が伝わりやすいのに対し、厚肉部１の周辺
部は、厚肉部１より早く冷却が進むため固化が進み、中
空部２内の加圧流体の圧力が伝わりにくい。その結果、
厚肉部対応面７が、その周辺部の表面より強く金型キャ
ビティ５の壁面に押し付けられて、両者間に光沢差を生
じるものと考えられる。First, in the case where the heat insulating material 4a or the heat storage material 4b is not provided, cooling of the thick portion 1 is likely to be delayed, and the pressure of the pressurized fluid in the hollow portion 2 is easily transmitted. Since cooling proceeds faster in the peripheral portion than in the thick portion 1, solidification proceeds, and the pressure of the pressurized fluid in the hollow portion 2 is less likely to be transmitted. as a result,
It is considered that the thick-walled portion-corresponding surface 7 is pressed against the wall surface of the mold cavity 5 more strongly than the surface of the peripheral portion thereof, thereby causing a gloss difference between the two.
【００２９】一方、本発明のように、厚肉部１の付け根
付近に相当する箇所に断熱材４ａ又は蓄熱材４ｂを設け
ておき、厚肉部１の付け根付近の樹脂の冷却を遅らせる
と、厚肉部１の付け根付近の樹脂の流動性が保たれる結
果、中空部２内の加圧流体の圧力が伝わりやすくなり、
厚肉部対応面７との間の金型転写性の差が軽減され、光
沢が実質的に同一となる。On the other hand, as in the present invention, when the heat insulating material 4a or the heat storage material 4b is provided at a location corresponding to the vicinity of the base of the thick portion 1 and the cooling of the resin near the base of the thick portion 1 is delayed, As a result of maintaining the fluidity of the resin near the base of the thick portion 1, the pressure of the pressurized fluid in the hollow portion 2 is easily transmitted,
The difference in mold transferability between the thick-walled portion corresponding surface 7 is reduced, and the gloss is substantially the same.
【００３０】即ち、本発明によると、中空部２内の加圧
流体の圧力が広い範囲にわたって伝達され、加圧流体の
圧力による金型キャビティ５の壁面への押し付け力がな
らされる結果、厚肉部対応面７の光沢がその周辺部の光
沢にまで緩和されて光沢差が実質的に同一となる。That is, according to the present invention, the pressure of the pressurized fluid in the hollow portion 2 is transmitted over a wide range, and the pressing force to the wall surface of the mold cavity 5 by the pressure of the pressurized fluid is leveled, resulting in a thickness The gloss of the flesh-corresponding surface 7 is reduced to the gloss of the peripheral portion, and the gloss difference becomes substantially the same.
【００３１】厚肉部対応面７とその周辺部間の光沢差
は、断熱材４ａ又は蓄熱材４ｂの設置範囲、その断熱性
や蓄熱量等によって相違する。肉眼で目立ちにくい光沢
差とする上で、厚肉部対応面７とその周辺部の各箇所で
の光沢度Ｇｓ（６０°）％の差が３％以下となるよう調
整することが好ましく、特にこれが２％以下となるよう
調整することが好ましい。The gloss difference between the thick-walled portion corresponding surface 7 and its peripheral portion differs depending on the installation range of the heat insulating material 4a or the heat storage material 4b, its heat insulating property, the amount of heat storage, and the like. In order to make the gloss difference that is inconspicuous to the naked eye, it is preferable to adjust so that the difference in the gloss level Gs (60 °)% between the thick-walled portion corresponding surface 7 and its peripheral portion is 3% or less, and particularly It is preferable to adjust this to be 2% or less.
【００３２】本発明に係る断熱材４ａ又は蓄熱材４ｂを
設けた金型で成形した成形品は、厚肉部１の付け根付近
がその周囲と相違する異表面１０となる。The molded product molded by the mold provided with the heat insulating material 4a or the heat storage material 4b according to the present invention has the different surface 10 near the base of the thick portion 1 different from the periphery thereof.
【００３３】上記異表面１０は、当該表面が断熱材４ａ
又は蓄熱材４ｂに接して形成された面であることから形
成されるもので、断熱材４ａ又は蓄熱材４ｂによる成形
跡として他の表面と区別できる。具体的には、金型構成
材料と熱伝導率が違う材料が存在することやその設置状
態により、他の表面より光沢がよいこと、全体がその周
辺よりやや凹又は凸となっていること、輪郭に沿って筋
状の凹部又は凸部が形成されていること等を生じ、これ
によって他の表面と区別できる。The different surface 10 has a heat insulating material 4a.
Alternatively, it is formed by being a surface formed in contact with the heat storage material 4b, and can be distinguished from other surfaces as a molding trace by the heat insulating material 4a or the heat storage material 4b. Specifically, depending on the presence of a material having a different thermal conductivity from the material constituting the mold and its installation state, it has better gloss than other surfaces, and the whole is slightly concave or convex from its periphery, For example, a streak-shaped concave portion or convex portion is formed along the contour, so that the surface can be distinguished from other surfaces.
【００３４】ところで、この異表面１０は厚肉部１を形
成する側の表面に形成されるので、これとは反対側であ
る厚肉部対応面７側が衣装面となる成形品については外
観に影響を与えない。By the way, since the different surface 10 is formed on the surface on which the thick portion 1 is formed, the appearance of the molded product whose opposite side is the thick portion corresponding surface 7 is the costume surface. It has no effect.
【００３５】本発明の中空射出成形は次のようにして行
われる。The hollow injection molding of the present invention is carried out as follows.
【００３６】まず、金型キャビティ５内に所定量の溶融
樹脂を射出し、金型キャビティ５内の溶融樹脂中に加圧
流体を圧入する。First, a predetermined amount of molten resin is injected into the mold cavity 5, and a pressurized fluid is pressed into the molten resin in the mold cavity 5.
【００３７】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、必要に応じて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 used, general thermoplastic resins used in general injection molding and extrusion molding can be used, and a thermosetting resin can also be used if necessary. Further, various additives, fillers, fillers and the like can be added and used as necessary.
【００３８】加圧流体は、射出ノズル８に内蔵させた加
圧流体ノズル９から、溶融樹脂と同じ経路を通って金型
キャビティ５内に圧入することができる。また、金型３
に直接設けた加圧流体ノズル（図示されていない）から
金型キャビティ５内に圧入することもできる。The pressurized fluid can be pressed into the mold cavity 5 from the pressurized fluid nozzle 9 built in the injection nozzle 8 through the same path as the molten resin. Also, mold 3
It is also possible to press fit into the mold cavity 5 from a pressurized fluid nozzle (not shown) provided directly in the.
【００３９】加圧流体は、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
融樹脂と反応又は相溶し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。The pressurized fluid is a gas or liquid at room temperature and normal pressure, and does not react with or be compatible with the molten resin used for molding under the temperature and pressure of injection molding. Examples of the gas include nitrogen gas, carbon dioxide gas, air, helium gas, glycerin, liquid paraffin, and molten resin, but an inert gas such as nitrogen gas is preferable. The pressure of the pressurized fluid is
Generally, it is about 10 to 500 kg / cm 2 .
【００４０】加圧流体の圧入タイミングは、通常の中空
射出成形と同様に、金型キャビティ５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５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 the pressurized fluid is the same as in normal hollow injection molding, after injecting (full shot) a sufficient amount of molten resin to fill the mold cavity 5 or inside the mold cavity 5. This is after injecting (short shot) an amount of molten resin that is insufficient to fill.
【００４１】加圧流体を圧入した後は、加圧流体の供給
弁を閉じて保圧する時間及び冷却時間を必要に応じて適
宜とった後、形成された中空部２内の加圧流体を排出し
てから成形品を金型３から取り出す。After the pressurizing fluid is press-fitted, after the pressure maintaining fluid supply valve is closed and the pressure holding time and the cooling time are appropriately set, the pressurizing fluid in the formed hollow portion 2 is discharged. After that, the molded product is taken out from the mold 3.
【００４２】ところで、本発明では、樹脂の冷却時に、
厚肉部１の付け根付近の樹脂の冷却をその周辺の樹脂の
冷却より遅延させる。これは、厚肉部１の付け根付近の
樹脂の柔軟性を、当該部分の表面が加圧流体の圧力で金
型キャビティ５の壁面に充分押し付けられるまで維持し
ておくためのものである。厚肉部１の付け根付近の樹脂
の冷却を遅延させるには、前述したように、所定の位置
に前述の断熱材４ａ又は蓄熱材４ｂを設けておくのが最
も簡便である。By the way, in the present invention, when the resin is cooled,
The cooling of the resin near the base of the thick portion 1 is delayed from the cooling of the resin around it. This is to maintain the flexibility of the resin near the base of the thick portion 1 until the surface of the portion is sufficiently pressed against the wall surface of the mold cavity 5 by the pressure of the pressurized fluid. In order to delay the cooling of the resin in the vicinity of the base of the thick portion 1, it is most convenient to provide the heat insulating material 4a or the heat storage material 4b at a predetermined position as described above.
【００４３】また、本発明に係る中空射出成形を行うに
際し、成形品表面の光沢を向上させる従来公知の手法を
併用し、得られる成形品全体の光沢を向上させることも
できる。Further, when the hollow injection molding according to the present invention is carried out, it is possible to improve the gloss of the obtained molded article as a whole by using a conventionally known method for improving the gloss of the surface of the molded article.
【００４４】例えば、金型キャビティ５の片面（断熱材
４ａ又は蓄熱材４ｂを設けていない、成形品の衣装面と
なる側）を高周波誘導もしくはその他の加熱手法で加熱
してから本発明の中空射出成形を行ったり、当該片面に
断熱フィルムを装着して本発明の中空射出成形を行うこ
とが挙げられる。For example, one side of the mold cavity 5 (the side which does not have the heat insulating material 4a or the heat storage material 4b and becomes the costume surface of the molded product) is heated by high frequency induction or another heating method, and then the hollow of the present invention. Examples of the method include injection molding or mounting the heat insulating film on the one surface to perform the hollow injection molding of the present invention.
【００４５】[0045]
実施例１ 図３に示される位置に断熱材４ａを設けた、図２に示さ
れるような成形装置を用い、図１に示されるような成形
品を成形した。断熱材４ａとしてはエポキシ樹脂（厚さ
５ｍｍ、幅１０ｍｍ）を使用した。Example 1 A molded product as shown in FIG. 1 was molded using a molding device as shown in FIG. 2 in which the heat insulating material 4a was provided at the position shown in FIG. An epoxy resin (thickness 5 mm, width 10 mm) was used as the heat insulating material 4a.
【００４６】成形条件は以下の通りである。The molding conditions are as follows.
【００４７】使用樹脂：ポリスチレン（旭化成工業社製
「Ｈ８６５２」をカーボンで黒色に着色したもの） 成形温度：２３０℃ 溶融樹脂の射出時間：１．２ｓｅｃ 使用加圧流体：窒素ガス 加圧流体の圧入及び保持時間：１５ｓｅｃ 冷却時間：４５ｓｅｃ 金型温度：４５℃Resin used: Polystyrene (H8652 manufactured by Asahi Kasei Kogyo Co., Ltd. colored in black with carbon) Molding temperature: 230 ° C. Injection time of molten resin: 1.2 sec Pressurized fluid: Nitrogen gas Pressurized fluid pressurization And holding time: 15 sec Cooling time: 45 sec Mold temperature: 45 ° C
【００４８】得られた成形品について、厚肉部対応面７
とその周辺部の光沢度Ｇｓ（６０°）を測定したとこ
ろ、厚肉部対応面７では４５％、その周辺部では４４％
で、厚肉部対応面７とその周辺部間の光沢差がわずかに
１％の成形品が得られた。With respect to the obtained molded product, the thick surface corresponding surface 7
And the glossiness Gs (60 °) of the peripheral portion thereof were measured, and it was 45% in the thick-walled portion corresponding surface 7 and 44% in the peripheral portion.
As a result, a molded product having a gloss difference of only 1% between the thick-walled portion corresponding surface 7 and its peripheral portion was obtained.
【００４９】実施例２ 実施例１における断熱材４ａに代えて、金型構成材料と
同じ材質の蓄熱材４ｂを実施例１の断熱材４ａと同様の
位置に嵌め込み、実施例１と同様にして同様の成形品の
成形を行った。Example 2 In place of the heat insulating material 4a in the first embodiment, a heat storage material 4b made of the same material as that of the mold was fitted at the same position as that of the heat insulating material 4a in the first embodiment, and in the same manner as in the first embodiment. A similar molded product was molded.
【００５０】得られた成形品について、厚肉部対応面７
とその周辺部の光沢度Ｇｓ（６０°）を測定したとこ
ろ、厚肉部対応面７では４５％、その周辺部では４５％
で、厚肉部対応面７とその周辺部間の光沢差がほとんど
ない成形品が得られた。For the obtained molded product, the surface 7 corresponding to the thick part
And the glossiness Gs (60 °) of the peripheral portion thereof were measured.
Thus, a molded product having almost no difference in gloss between the thick-walled portion corresponding surface 7 and its peripheral portion was obtained.
【００５１】実施例３ 断熱材４ａの設置位置を図４に示されるような位置とし
た以外は実施例１と同様にして同様の成形品の成形を行
った。Example 3 A similar molded product was molded in the same manner as in Example 1 except that the installation position of the heat insulating material 4a was changed to the position shown in FIG.
【００５２】得られた成形品について、厚肉部対応面７
とその周辺部の光沢度Ｇｓ（６０°）を測定したとこ
ろ、厚肉部対応面７では４６％、その周辺部では４４％
で、厚肉部対応面７とその周辺部間の光沢差は２％であ
るが、肉眼ではほとんど差を感じない成形品が得られ
た。With respect to the obtained molded product, the thick surface corresponding surface 7
And the glossiness Gs (60 °) of the peripheral portion thereof were measured and found to be 46% for the thick-walled surface 7 and 44% for the peripheral portion.
Then, although the gloss difference between the thick-walled portion corresponding surface 7 and its peripheral portion was 2%, a molded product was obtained in which almost no difference was perceived by the naked eye.
【００５３】比較例１ 図１に示される形状の成形品を成形するための通常の金
型（断熱材のない金型）を用いた以外は実施例１と同様
にして同様の成形品の成形を行った。Comparative Example 1 Molding of a molded product similar to that of Example 1 except that a normal mold (mold without a heat insulating material) for molding a molded product having the shape shown in FIG. 1 was used. I went.
【００５４】得られた成形品について、厚肉部対応面７
とその周辺部の光沢度Ｇｓ（６０°）を測定したとこ
ろ、厚肉部対応面７では５４％、その周辺部では４５％
で、厚肉部対応面７とその周辺部間の光沢差は９％もあ
り、肉眼ではっきり光沢の差が認められた。With respect to the obtained molded product, the thick surface corresponding surface 7
And the glossiness Gs (60 °) of the peripheral portion thereof were measured and found to be 54% for the thick wall corresponding surface 7 and 45% for the peripheral portion.
The difference in gloss between the surface 7 corresponding to the thick portion and its peripheral portion was 9%, and the difference in gloss was clearly visible to the naked eye.
【００５５】[0055]
【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.
【００５６】（１）断熱材４ａや蓄熱材４ｂを部分的に
設けるだけで、大掛かりな金型変更を行うことなく、厚
肉部対応面７とその周辺部間の光沢差を解消することが
でき、設備的負担が小さい。(1) By only partially providing the heat insulating material 4a and the heat storage material 4b, it is possible to eliminate the difference in gloss between the thick-walled portion corresponding surface 7 and its peripheral portion without making a large-scale mold change. It is possible, and the facility burden is small.
【００５７】（２）厚肉部対応面とその周辺部間に光沢
差を生じないので、成形品に厚めのメッキ等の二次加工
を施して表面を整えることなく直ちに製品として使用す
ることができ、二次加工を省略することによる製品のコ
ストダウンを図れる。(2) Since there is no difference in gloss between the surface corresponding to the thick portion and its peripheral portion, it is possible to immediately use it as a product without subjecting the molded product to secondary processing such as thick plating to prepare the surface. Therefore, the cost of the product can be reduced by omitting the secondary processing.
【図１】本発明による成形品の一例を示す断面図であ
る。FIG. 1 is a cross-sectional view showing an example of a molded product according to the present invention.
【図２】図１に示される成形品を成形するための金型回
りを示す図である。FIG. 2 is a diagram showing the periphery of a mold for molding the molded product shown in FIG.
【図３】断熱材又は蓄熱材の設置状態の一例を示す図で
ある。FIG. 3 is a diagram showing an example of an installed state of a heat insulating material or a heat storage material.
【図４】断熱材又は蓄熱材の設置状態の他の例を示す図
である。FIG. 4 is a diagram showing another example of an installed state of a heat insulating material or a heat storage material.
【図５】断熱材又は蓄熱材の設置状態の他の例を示す図
である。FIG. 5 is a diagram showing another example of an installed state of a heat insulating material or a heat storage material.
【図６】断熱材又は蓄熱材の設置状態の他の例を示す図
である。FIG. 6 is a diagram showing another example of an installed state of a heat insulating material or a heat storage material.
１ 厚肉部 ２ 中空部 ３ 金型 ３ａ 固定型 ３ｂ 移動型 ４ａ 断熱材 ４ｂ 蓄熱材 ５ 金型キャビティ ６ 凹部 ７ 厚肉部対応面 ８ 射出ノズル ９ 加圧流体ノズル １０ 異表面 1 Thick Part 2 Hollow Part 3 Mold 3a Fixed Type 3b Movable Type 4a Heat Insulation Material 4b Heat Storage Material 5 Mold Cavity 6 Recess 7 Thick Surface Corresponding Surface 8 Injection Nozzle 9 Pressurized Fluid Nozzle 10 Different Surface
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｂ２９Ｃ 49/62 7619−4Ｆ // Ｂ２９Ｌ 22:00 ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Office reference number FI technical display location B29C 49/62 7619-4F // B29L 22:00
Claims (3)
に中空部を形成する中空射出成形において、厚肉部の付
け根付近の樹脂の冷却をその周辺の樹脂の冷却より遅延
させることを特徴とする中空射出成形方法。1. In hollow injection molding in which a hollow portion is formed in a thick portion of a molded product having a partially thick portion, cooling of the resin near the base of the thick portion is delayed from cooling of the resin around it. A hollow injection molding method characterized by the above.
に中空部を形成する中空射出成形に用いる金型におい
て、厚肉部の付け根付近に相当する箇所に断熱材が設け
られていることを特徴とする金型。2. A mold used for hollow injection molding for forming a hollow portion in a thick portion of a molded product having a partially thick portion, wherein a heat insulating material is provided at a location corresponding to the vicinity of the root of the thick portion. Mold that is characterized by.
に中空部を形成する中空射出成形に用いる金型におい
て、厚肉部の付け根付近に相当する箇所に、金型との間
に断熱層を介在させた蓄熱材が設けられていることを特
徴とする金型。3. A mold used for hollow injection molding for forming a hollow portion in a thick portion of a molded product having a partial thick portion, in a portion corresponding to the vicinity of the root of the thick portion, A mold comprising a heat storage material having a heat insulating layer interposed therebetween.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32335493A JPH07148766A (en) | 1993-11-30 | 1993-11-30 | Hollow injection molding method and mold |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32335493A JPH07148766A (en) | 1993-11-30 | 1993-11-30 | Hollow injection molding method and mold |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07148766A true JPH07148766A (en) | 1995-06-13 |
Family
ID=18153850
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32335493A Withdrawn JPH07148766A (en) | 1993-11-30 | 1993-11-30 | Hollow injection molding method and mold |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07148766A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001171677A (en) * | 1999-12-10 | 2001-06-26 | Sanko Co Ltd | Transport container |
| JP2002172655A (en) * | 2000-12-05 | 2002-06-18 | Taiyo Manufacturing Co Ltd | Injection mold for thermoplastic resin |
| JP2006003685A (en) * | 2004-06-18 | 2006-01-05 | Ricoh Co Ltd | Structure for screening handle drawing-out aperture and image forming apparatus provided with the same |
-
1993
- 1993-11-30 JP JP32335493A patent/JPH07148766A/en not_active Withdrawn
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001171677A (en) * | 1999-12-10 | 2001-06-26 | Sanko Co Ltd | Transport container |
| JP2002172655A (en) * | 2000-12-05 | 2002-06-18 | Taiyo Manufacturing Co Ltd | Injection mold for thermoplastic resin |
| JP4725906B2 (en) * | 2000-12-05 | 2011-07-13 | 浩之 石見 | Mold for thermoplastic resin injection molding |
| JP2006003685A (en) * | 2004-06-18 | 2006-01-05 | Ricoh Co Ltd | Structure for screening handle drawing-out aperture and image forming apparatus provided with the same |
| JP4587204B2 (en) * | 2004-06-18 | 2010-11-24 | 株式会社リコー | Image forming apparatus |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20010130 |