JPH0847940A - Injection molding method for resin molding having thick-wall part - Google Patents
Injection molding method for resin molding having thick-wall partInfo
- Publication number
- JPH0847940A JPH0847940A JP18362394A JP18362394A JPH0847940A JP H0847940 A JPH0847940 A JP H0847940A JP 18362394 A JP18362394 A JP 18362394A JP 18362394 A JP18362394 A JP 18362394A JP H0847940 A JPH0847940 A JP H0847940A
- Authority
- JP
- Japan
- Prior art keywords
- thermoplastic resin
- thick
- base material
- injection
- mold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
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
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は厚肉部を有する樹脂成形
品の射出成形方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of injection molding a resin molded product having a thick portion.
【０００２】[0002]
【従来の技術】射出成形品がリブ等の突起部（厚肉部）
を有している場合、射出後の冷却に伴う樹脂の体積収縮
により、該成形品の突起部（厚肉部）の周辺、例えば、
突起部が存在する面と反対側の面（裏面側）の位置（厚
肉部に相当する部位）に、所謂、「ヒケ（凹み）」が発
生する。従来、この様な「ヒケ」の防止方法として、突
起部（厚肉部）にガスを注入することによる中空部を有
する成形品の成形方法が提案されているが、かかる方法
を用いることにより「ヒケ」の発生を有効に防止するこ
とができる。しかしながら、上記のガス注入法を用いた
場合、ガスを注入した部分はガス圧により内圧が高いこ
とから金型への密着性が十分に確保され、その周辺の注
入していない部分に比して、突起部（厚肉部）が存在す
る面と反対側の面（裏面側）の位置（厚肉部に相当する
部位）は金型表面の転写性が良好となり、裏面側の表面
部分に光沢ムラが発生するという問題がある。一方、第
１の熱可塑性樹脂を射出成形することにより第１の層を
形成する第１工程と、第２の熱可塑性樹脂を射出成形す
ることにより第２の層を形成する第２工程よりなる多層
射出成形法については、既に公知である。2. Description of the Related Art Injection-molded products have ribs or other protrusions (thick parts)
In the case where the molded article has the following, due to the volumetric shrinkage of the resin accompanying cooling after injection, the periphery of the protrusion (thick part) of the molded article, for example,
A so-called "sink (depression)" is generated at a position (a portion corresponding to a thick portion) on the surface (back surface side) opposite to the surface on which the protrusion is present. Heretofore, as a method of preventing such a "sink", there has been proposed a method of molding a molded product having a hollow portion by injecting a gas into a protruding portion (thick wall portion). It is possible to effectively prevent the occurrence of a sink mark. However, when the above-mentioned gas injection method is used, since the gas-injected portion has a high internal pressure due to the gas pressure, sufficient adhesion to the mold is ensured, and the surrounding portion is less than the non-injected portion. , The position of the surface (rear surface side) opposite to the surface where the protrusion (thick portion) is present (the portion corresponding to the thick portion) has good transferability of the mold surface, and the surface of the back surface is glossy. There is a problem that unevenness occurs. On the other hand, it comprises a first step of forming a first layer by injection molding a first thermoplastic resin and a second step of forming a second layer by injection molding a second thermoplastic resin. The multilayer injection molding method is already known.
【０００３】[0003]
【発明が解決しようとする課題】本発明は厚肉部を有す
る射出成形品において該厚肉部をガス注入により中空化
させることにより「ヒケ」の発生を防止すると共に、ガ
ス注入により突起部（厚肉部）が存在する面と反対側の
面（裏面側）の表面に発生する光沢ムラをなくした、厚
肉部を有する樹脂成形品の射出成形方法を提供すること
を目的とする。DISCLOSURE OF THE INVENTION According to the present invention, in an injection-molded article having a thick wall portion, the thick wall portion is hollowed by injecting gas to prevent the occurrence of "sink", and at the same time, by injecting gas, the protrusion ( An object of the present invention is to provide an injection molding method for a resin molded product having a thick portion, in which uneven gloss generated on the surface (back surface side) opposite to the surface having the thick portion) is eliminated.
【０００４】[0004]
【課題を解決するための手段】本発明者らは、上記目的
を達成すべく鋭意研究を重ねた結果、中空射出成形によ
って成形された中空状の厚肉部を有する熱可塑性樹脂製
基材の該厚肉部が存在する面の裏面の基材表面に熱可塑
性樹脂製被覆材を積層することにより、本発明を完成す
るに至ったものである。すなわち、本発明の厚肉部を有
する樹脂成形品の射出成形方法は、金型内で、厚肉部を
有する熱可塑性樹脂製基材を、該厚肉部にガスを注入し
て中空射出成形した後、該厚肉部の突起部が存在する面
と反対側の基材表面上に熱可塑性樹脂製被覆材を射出成
形して積層することを特徴とするものである。本発明の
もう一方の発明である厚肉部を有する樹脂成形品の射出
成形方法は、金型内で熱可塑性樹脂製被覆材を射出成形
した後、或いは、予め射出成形した熱可塑性樹脂製被覆
材を金型内にインサートした後、厚肉部を有する熱可塑
性樹脂製基材を、該熱可塑性樹脂製被覆材側に該熱可塑
性樹脂製基材の厚肉部の突起部が存在する面と反対側の
面を位置させて、該厚肉部にガスを注入して中空射出成
形して積層することを特徴とするものである。Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a thermoplastic resin base material having a hollow thick portion formed by hollow injection molding is used. The present invention has been completed by laminating a thermoplastic resin coating material on the surface of the base material on the back surface of the surface where the thick portion is present. That is, an injection molding method for a resin molded product having a thick portion of the present invention is a method of hollow injection molding a thermoplastic resin base material having a thick portion in a mold by injecting gas into the thick portion. After that, the thermoplastic resin coating material is injection-molded and laminated on the surface of the base material on the opposite side of the surface of the thick portion where the protrusions are present. Another aspect of the present invention is an injection molding method for a resin molded product having a thick portion, which is performed by injection molding a thermoplastic resin coating material in a mold, or by performing a thermoplastic resin coating pre-injected. After the material is inserted into the mold, a thermoplastic resin base material having a thick wall portion is provided on the thermoplastic resin base material side, on which the protrusions of the thick wall portion of the thermoplastic resin base material are present. It is characterized in that a surface on the opposite side is positioned and gas is injected into the thick portion to perform hollow injection molding and stacking.
【０００５】[0005]
[1] 原材料 (1) 熱可塑性樹脂製基材材料 本発明において用いられる熱可塑性樹脂製基材材料とし
ては、ＪＩＳ−Ｋ７２０３による曲げ弾性率が３，００
０ｋｇｆ／ｃｍ2 以上の熱可塑性樹脂が好ましく、特に
５，０００ｋｇｆ／ｃｍ2 以上の熱可塑性樹脂が好適で
ある。具体的には、中密度、高密度のポリエチレン、ポ
リプロピレン等のポリオレフィン系樹脂；ポリスチレ
ン、アクリロニトリル・スチレン共重合体、アクリロニ
トリル・ブタジエン・スチレン共重合体等のポリスチレ
ン系樹脂；ポリエチレンテレフタレート、ポリブチレン
テレフタレート等のポリエステル系樹脂；ポリオキシメ
チレンホモポリマー、ポリオキシメチレンコポリマー等
のポリオキシメチレン系樹脂；ポリメチルメタクリレー
ト系樹脂等を挙げることができる。これらの熱可塑性樹
脂の中でも、高密度ポリエチレン、ポリプロピレン等の
ポリオレフィン系樹脂、ポリスチレン、アクリロニトリ
ル・スチレン共重合体、アクリロニトリル・ブタジエン
・スチレン共重合体等のポリスチレン系樹脂、ポリエチ
レンテレフタレート、ポリブチレンテレフタレート等の
ポリエステル系樹脂を用いることが好ましく、特に高密
度ポリエチレン、ポリプロピレン等のポリオレフィン系
樹脂を用いることが好ましい。[1] Raw Material (1) Thermoplastic Resin Base Material The thermoplastic resin base material used in the present invention has a flexural modulus of 3,000 according to JIS-K7203.
Preferably 0 kgf / cm 2 or more thermoplastic resin, it is particularly preferred 5,000 kgf / cm 2 or more thermoplastic resin. Specifically, medium density, high density polyolefin resins such as polyethylene and polypropylene; polystyrene, polystyrene resins such as acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer; polyethylene terephthalate, polybutylene terephthalate, etc. Examples of the polyester resin include polyoxymethylene homopolymers, polyoxymethylene copolymers and other polyoxymethylene resins, and polymethylmethacrylate resins. Among these thermoplastic resins, high density polyethylene, polyolefin resin such as polypropylene, polystyrene, polystyrene resin such as acrylonitrile / styrene copolymer, acrylonitrile / butadiene / styrene copolymer, polyethylene terephthalate, polybutylene terephthalate, etc. It is preferable to use a polyester resin, and it is particularly preferable to use a polyolefin resin such as high-density polyethylene or polypropylene.
【０００６】これら熱可塑性樹脂製基材材料は、上記熱
可塑性樹脂製基材材料を単独で用いたものでも、複数の
熱可塑性樹脂製基材材料のブレンド物であってもよい。
また、該熱可塑性樹脂製基材材料は、他の樹脂や、エチ
レン・プロピレン共重合体、エチレン・プロピレン・非
共役ジエン共重合体、エチレン・ブテン共重合体、エチ
レン・プロピレン・ブテン共重合体等のオレフィン系エ
ラストマー；スチレン・ブタジエン・スチレンブロック
共重合体、及びその水素添加物、スチレン・イソプレン
・スチレンブロック共重合体、及びその水素添加物、ス
チレン・ブタジエン・イソプレン・スチレンブロック共
重合体、及びその水素添加物、スチレン・ブタジエンラ
ンダム共重合体等のスチレン系エラストマー；ポリブタ
ジエン等のエラストマー、或いは、タルク、炭酸カルシ
ウム、ガラス繊維等のフィラー；パラフィンオイル等の
可塑剤；酸化防止剤、熱安定剤、光安定剤、紫外線吸収
剤、中和剤、滑剤、潤滑剤、防曇剤、ブロッキング防止
剤、スリップ剤、分散剤、着色剤、防菌剤、蛍光漂白剤
等といった各種添加剤等を配合したコンパウンド物とし
て用いても良い。These thermoplastic resin base materials may be the above thermoplastic resin base materials alone or a blend of a plurality of thermoplastic resin base materials.
Further, the thermoplastic resin base material is another resin, ethylene / propylene copolymer, ethylene / propylene / non-conjugated diene copolymer, ethylene / butene copolymer, ethylene / propylene / butene copolymer. Olefin elastomers such as; styrene / butadiene / styrene block copolymers and hydrogenated products thereof, styrene / isoprene / styrene block copolymers and hydrogenated products thereof, styrene / butadiene / isoprene / styrene block copolymers, And hydrogenated products thereof, styrene-based elastomers such as styrene / butadiene random copolymers; elastomers such as polybutadiene, or fillers such as talc, calcium carbonate, glass fiber; plasticizers such as paraffin oil; antioxidants, heat stability Agents, light stabilizers, UV absorbers, neutralizing agents, lubricants Lubricants, antifogging agents, antiblocking agents, slip agents, dispersing agents, coloring agents, antibacterial agent, may be used as a compound prepared by blending various additives such as such as fluorescent whitening agent.
【０００７】(2) 熱可塑性樹脂製被覆材材料 本発明において用いられる熱可塑性樹脂製被覆材材料と
しては、例えば、オレフィン系熱可塑性エラストマー、
スチレン系熱可塑性エラストマー、ポリウレタン系熱可
塑性エラストマー、ポリエステル系熱可塑性エラストマ
ー等の各種熱可塑性エラストマー、軟質塩化ビニル樹
脂、塩素化ポリエチレン樹脂、エチレン・アクリル酸共
重合体樹脂、エチレン・アクリル酸メチル共重合体樹脂
等のエチレン・アクリル酸エステル共重合体樹脂、エチ
レン・酢酸ビニル共重合体樹脂、ポリブテン−１樹脂、
エチレンの単独重合体である低密度、高密度ポリエチレ
ン樹脂、中低圧法により得られるエチレンとα−オレフ
ィンとの共重合体である低密度、中密度、高密度ポリエ
チレン樹脂、プロピレンの単独重合体であるポリプロピ
レン樹脂、プロピレンとα−オレフィンとの共重合体樹
脂等を挙げることができる。(2) Thermoplastic resin coating material The thermoplastic resin coating material used in the present invention is, for example, an olefinic thermoplastic elastomer,
Various thermoplastic elastomers such as styrene-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, soft vinyl chloride resin, chlorinated polyethylene resin, ethylene / acrylic acid copolymer resin, ethylene / methyl acrylate copolymer Ethylene / acrylic ester copolymer resins such as united resins, ethylene / vinyl acetate copolymer resins, polybutene-1 resins,
A low-density, high-density polyethylene resin that is a homopolymer of ethylene, a low-density, medium-density, high-density polyethylene resin that is a copolymer of ethylene and α-olefin obtained by the medium-low pressure method, and a homopolymer of propylene. Examples thereof include certain polypropylene resins, copolymer resins of propylene and α-olefin, and the like.
【０００８】これらの熱可塑性樹脂被覆材材料の中で
も、オレフィン系熱可塑性エラストマー、スチレン系熱
可塑性エラストマー、エチレン・酢酸ビニル共重合体樹
脂、エチレン・アクリル酸メチル共重合体樹脂、ポリブ
テン−１樹脂、低密度、中密度、高密度ポリエチレン、
ポリプロピレン等のポリオレフィン系樹脂を用いること
が好ましい。これら熱可塑性樹脂製被覆材材料は、上記
熱可塑性樹脂製被覆材材料を単独で用いたものでも、複
数の熱可塑性樹脂製被覆材材料のブレンド物であっても
よい。また、該熱可塑性樹脂製被覆材材料は、他のエラ
ストマーや、ポリプロピレン、高密度ポリエチレン等の
樹脂、タルクや炭酸カルシウム等のフィラー、パラフィ
ンオイル等の可塑剤、酸化防止剤、熱安定剤、光安定
剤、紫外線吸収剤、中和剤、滑剤、潤滑剤、防曇剤、ブ
ロッキング防止剤、スリップ剤、分散剤、着色剤、防菌
剤、蛍光漂白剤等といった、各種配合添加剤を配合した
コンパウンド物として用いても良い。Among these thermoplastic resin coating materials, olefinic thermoplastic elastomer, styrene thermoplastic elastomer, ethylene / vinyl acetate copolymer resin, ethylene / methyl acrylate copolymer resin, polybutene-1 resin, Low density, medium density, high density polyethylene,
It is preferable to use a polyolefin resin such as polypropylene. These thermoplastic resin coating material materials may be the above thermoplastic resin coating material materials alone or may be a blend of a plurality of thermoplastic resin coating material materials. Further, the thermoplastic resin coating material includes other elastomers, resins such as polypropylene and high-density polyethylene, fillers such as talc and calcium carbonate, plasticizers such as paraffin oil, antioxidants, heat stabilizers, and light stabilizers. Various additives such as stabilizers, UV absorbers, neutralizers, lubricants, lubricants, antifogging agents, antiblocking agents, slip agents, dispersants, colorants, antibacterial agents, fluorescent bleaching agents, etc. have been added. It may be used as a compound.
【０００９】[2] 成形加工 (1) 熱可塑性樹脂製基材 (a) 形 状 本発明における熱可塑性樹脂製基材とは、リブ等の突起
部を形成した厚肉部を有する平板状あるいは箱状形状の
ものであり、基本肉厚が１〜１０ｍｍ程度のものであ
り、その形状は平面状あるいは曲面状のどちらであって
もかまわない。厚肉部の形状については、幅２〜２０ｍ
ｍ程度、高さ３〜２５ｍｍ程度のリブ等の突起状のもの
である。厚肉部は、任意の場所に、任意の数設置しても
かまわない。[2] Molding (1) Thermoplastic resin base material (a) Shape The thermoplastic resin base material in the present invention means a flat plate shape having a thick portion formed with protrusions such as ribs or It has a box shape and a basic wall thickness of about 1 to 10 mm, and the shape may be either flat or curved. Regarding the shape of the thick part, the width is 2 to 20 m
It is a protrusion such as a rib having a height of about m and a height of about 3 to 25 mm. The thick portion may be installed in any place and in any number.
【００１０】(b) 成形方法 本発明における熱可塑性樹脂製基材は、金型内に基材材
料を射出した後、リブ等の突起状の厚肉部にガスを注入
して得るものであるが、本方法は公知の中空射出成形
法、例えば、特開昭６３−２６８６１１号公報等に記載
される方法により得られるものである。(B) Molding Method The thermoplastic resin substrate in the present invention is obtained by injecting a substrate material into a mold and then injecting gas into a protruding thick portion such as a rib. However, this method is obtained by a known hollow injection molding method, for example, the method described in JP-A-63-268611.
【００１１】(2) 熱可塑性樹脂製被覆材 (a) 形 状 本発明における熱可塑性樹脂製被覆材は、厚み１〜５ｍ
ｍが好ましく、特に１．５〜３ｍｍが好適である。 (b) 成形方法 本発明における熱可塑性樹脂製被覆材は、射出成形によ
って得られるものである。(2) Thermoplastic resin coating material (a) Shape The thermoplastic resin coating material in the present invention has a thickness of 1 to 5 m.
m is preferable, and 1.5 to 3 mm is particularly preferable. (b) Molding method The thermoplastic resin coating material in the present invention is obtained by injection molding.
【００１２】(3) 射出成形順序 本発明において最終成形品を得る方法としては、熱可塑
性樹脂製基材を中空射出成形後、熱可塑性樹脂製被覆材
を射出成形して積層させる方法、熱可塑性樹脂製被覆材
を射出成形するかあるいは射出成形した熱可塑性樹脂被
覆材を金型内にインサートした後、熱可塑性樹脂製基材
を中空射出成形する方法を挙げることができる。具体的
には、 (A) 熱可塑性樹脂製基材を厚肉部にガスを注入して中空
射出成形した後、厚肉部の突起部が存在する面と反対側
の基材表面に、熱可塑性樹脂製被覆材を射出成形し、熱
融着により積層させる方法。 (B) 熱可塑性樹脂製被覆材を射出成形後、厚肉部を有す
る熱可塑性樹脂製基材を厚肉部にガスを注入して中空射
出成形し熱融着により積層させる方法。 (C) あらかじめ射出成形により得られた熱可塑性樹脂製
被覆材を金型内にインサートした後、厚肉部を有する熱
可塑性樹脂製基材を厚肉部にガスを注入して中空射出成
形し熱融着により積層させる方法。等を挙げることがで
きる。(3) Injection molding sequence In the present invention, the final molded article can be obtained by hollow injection molding a thermoplastic resin base material and then injection molding a thermoplastic resin coating material to laminate the thermoplastic resin base material. Examples include a method in which the resin coating material is injection-molded, or the injection-molded thermoplastic resin coating material is inserted into a mold, and then the thermoplastic resin base material is subjected to hollow injection molding. Specifically, (A) a thermoplastic resin base material is injected into the thick wall portion by gas injection molding, and then the base material surface opposite to the surface of the thick wall portion where the protruding portion is present is heated. A method in which a plastic resin coating material is injection-molded and laminated by heat fusion. (B) A method in which a thermoplastic resin coating material is injection molded, and then a thermoplastic resin base material having a thick portion is injected into the thick portion by hollow injection molding and laminated by heat fusion. (C) A thermoplastic resin coating material obtained by injection molding in advance is inserted into a mold, and then a thermoplastic resin substrate having a thick portion is injected into the thick portion by gas injection molding. A method of laminating by heat fusion. Etc. can be mentioned.
【００１３】[3] 射出成形品 上記のようにして成形された樹脂成形品は、厚肉部にガ
スを注入することにより「ヒケ」の発生を防止すると共
に、ガス注入により裏面に発生する光沢ムラが被覆材に
より覆い隠されているので、表面外観が良好である。従
って、該樹脂成形品は、例えば、インストルメントパネ
ル、センタークラスター、アームレスト等の自動車の内
装部品や、パンパー、サイドモール等の外装部品として
工業的に有用なものである。[3] Injection-Molded Product The resin-molded product molded as described above prevents the generation of “sinks” by injecting gas into the thick-walled portion, and the gloss generated on the back surface by gas injection. Since the unevenness is covered with the covering material, the surface appearance is good. Therefore, the resin molded product is industrially useful as, for example, an automobile interior part such as an instrument panel, a center cluster and an armrest, and an exterior part such as a bumper and a side molding.
【００１４】[0014]
【実施例】実施例１ ［第１の熱可塑性樹脂］ＭＦＲ（２３０℃、２．１６ｋ
ｇ荷重）が８．０ｇ／１０分、曲げ弾性率が２５，００
０ｋｇｆ／ｃｍ2 であり、ポリプロピレン樹脂（三菱油
化（株）製三菱ポリプロＴＡ３）と、タルクを７：３の
割合で単軸押出機で混合したコンパウンドを用いた。 ［第２の熱可塑性樹脂］ＭＦＲが２０ｇ／１０分、曲げ
弾性率が６００ｋｇｆ／ｃｍ2 であるスチレン系熱可塑
性エラストマー（三菱油化（株）製ＳＪ８４００Ｂ）を
用いた。 ［射出成形］１２０ｍｍ×１２０ｍｍ×肉厚３ｍｍの平
板状であり、その中央部に幅１０ｍｍ、高さ１０ｍｍの
突起部（厚肉部）をコア側キャビティーに有する第１の
金型を用い、該金型のキャビティ表面を４０℃の温度に
加熱し、製品上部にあるゲートより上記第１の熱可塑性
樹脂をシリンダー温度２２０℃で、１．０ｋｇ／分の射
出速度、６００ｋｇｆ／ｃｍ2 の射出圧力で射出した
後、厚肉部に窒素ガスを３０ｋｇｆ／ｃｍ2 の圧力で注
入して中空部を有する熱可塑性樹脂製基材を成形した。
次に、基材を１２０ｍｍ×１２０ｍｍ×肉厚５ｍｍの平
板状の第２の金型キャビティ内に設置した後、上記第２
の熱可塑性樹脂をシリンダー温度２２０℃で、１．０ｋ
ｇ／分の射出速度、６００ｋｇｆ／ｃｍ2 で射出し、基
材に熱融着させ、本発明の成形品を成形した。この結
果、厚肉部に光沢ムラが無く、ヒケも無い、表面外観の
良好な成形品が得られた。EXAMPLES Example 1 [First thermoplastic resin] MFR (230 ° C., 2.16 k)
g load) is 8.0 g / 10 minutes, flexural modulus is 25,000
It was 0 kgf / cm 2 , and a compound was used in which polypropylene resin (Mitsubishi Polychemical TA3 manufactured by Mitsubishi Petrochemical Co., Ltd.) and talc were mixed at a ratio of 7: 3 in a single-screw extruder. [Second thermoplastic resin] A styrene-based thermoplastic elastomer (SJ8400B manufactured by Mitsubishi Petrochemical Co., Ltd.) having an MFR of 20 g / 10 minutes and a flexural modulus of 600 kgf / cm 2 was used. [Injection molding] A first mold having a flat plate shape of 120 mm × 120 mm × thickness 3 mm and having a protrusion (thick part) having a width of 10 mm and a height of 10 mm in the center thereof in the core side cavity is used. The cavity surface of the mold is heated to a temperature of 40 ° C., and the first thermoplastic resin is injected from a gate on the upper part of the product at a cylinder temperature of 220 ° C. at an injection speed of 1.0 kg / min and 600 kgf / cm 2 . After injecting under pressure, nitrogen gas was injected into the thick portion at a pressure of 30 kgf / cm 2 to form a thermoplastic resin base material having a hollow portion.
Next, after the base material is placed in a flat second mold cavity of 120 mm × 120 mm × thickness 5 mm, the above second
1.0 k of thermoplastic resin at a cylinder temperature of 220 ° C
Injection was performed at an injection speed of g / min and 600 kgf / cm 2 , and the base material was heat-sealed to form the molded article of the present invention. As a result, a molded product having a good surface appearance with no uneven gloss in the thick portion and no sink mark was obtained.
【００１５】比較例１ 実施例１と同様の金型、熱可塑性樹脂を用いた。第１の
熱可塑性樹脂を４０℃の温度に加熱した第１の金型キャ
ビティ内にシリンダー温度２２０℃で、１．０ｋｇ／分
の射出速度、６００ｋｇｆ／ｃｍ2 で射出し、成形品を
成形した。次に、基材を第２の金型キャビティ内に設置
した後、第２の熱可塑性樹脂をシリンダー温度２２０℃
で、１．０ｋｇ／分の射出速度、６００ｋｇｆ／ｃｍ2
で射出し、成形品を得た。この結果、厚肉部の裏面付近
で、第１の熱可塑性樹脂部に“ヒケ”が生じ、第２の熱
可塑性樹脂がその部位に過剰に充填され盛り上がった様
になり、表面外観が良くなかった。 Comparative Example 1 The same mold and thermoplastic resin as in Example 1 were used. The first thermoplastic resin was injected into the first mold cavity heated to a temperature of 40 ° C. at a cylinder temperature of 220 ° C. at an injection speed of 1.0 kg / min and 600 kgf / cm 2 to form a molded product. . Next, after placing the base material in the second mold cavity, the second thermoplastic resin is placed at a cylinder temperature of 220 ° C.
At an injection speed of 1.0 kg / min, 600 kgf / cm 2
Then, a molded product was obtained. As a result, near the back surface of the thick portion, a sink mark was generated in the first thermoplastic resin portion, and the second thermoplastic resin was excessively filled in that portion and swelled up, resulting in a poor surface appearance. It was
【００１６】実施例２ 実施例１と同様の金型を用いた。実施例１で用いたもの
と同じ第１の熱可塑性樹脂を４０℃の温度に加熱した第
１の金型キャビティ内にシリンダー温度２２０℃で、
１．０ｋｇ／分の射出速度、６００ｋｇｆ／ｃｍ2 で射
出した後、厚肉部に窒素ガスを３０ｋｇｆ／ｃｍ2で注
入し、中空部を有する熱可塑性樹脂製基材を成形した。
次に、基材を第２の金型キャビティに設置した後、第２
の熱可塑性樹脂として、ＭＦＲが３０ｇ／１０分、曲げ
弾性率が１５，０００ｋｇｆ／ｃｍ2 であるプロピレン
・エチレン共重合体樹脂（三菱油化（株）製「三菱ポリ
プロ ＢＣ０３Ｃ」）をシリンダー温度２２０℃で、
１．０ｋｇ／分の射出速度、６００ｋｇｆ／ｃｍ2 で射
出し、基材に熱融着させ、本発明の成形品を成形した。
この結果、成形品において中空化した厚肉部近辺にヒケ
や光沢ムラが無い、表面外観の良好な成形品が得られ
た。 Example 2 A mold similar to that of Example 1 was used. The same first thermoplastic resin as used in Example 1 was heated to a temperature of 40 ° C. in a first mold cavity at a cylinder temperature of 220 ° C.,
1.0 kg / min injection speed after injection with 600 kgf / cm 2, the nitrogen gas in the thick portion was injected at 30 kgf / cm 2, was molded thermoplastic resin base material having a hollow portion.
Next, after placing the substrate in the second mold cavity, the second
As the thermoplastic resin, a propylene / ethylene copolymer resin (“Mitsubishi Polypro BC03C” manufactured by Mitsubishi Petrochemical Co., Ltd.) having a MFR of 30 g / 10 minutes and a flexural modulus of 15,000 kgf / cm 2 is used. At ℃,
Injection was performed at an injection speed of 1.0 kg / min and 600 kgf / cm 2 , and heat fusion was performed on the base material to form the molded article of the present invention.
As a result, a molded product having a good surface appearance without sink marks or uneven gloss around the hollowed-out thick portion was obtained.
【００１７】比較例２ 実施例１の第１の金型と同様の金型を用いた。また、熱
可塑性樹脂は実施例１の第１の熱可塑性樹脂と同様のも
のを用いた。熱可塑性樹脂を表面を４０℃の温度に加熱
した金型キャビティ内にシリンダー温度２２０℃で、
１．０ｋｇ／分の射出速度、６００ｋｇｆ／ｃｍ2 の射
出圧力で射出し、厚肉部を有する成形品を成形した。こ
の結果、厚肉部で“ヒケ”が生じ、成形品の表面外観が
悪かった。 Comparative Example 2 A mold similar to the first mold of Example 1 was used. The same thermoplastic resin as the first thermoplastic resin of Example 1 was used. At a cylinder temperature of 220 ° C. in a mold cavity in which the surface of the thermoplastic resin is heated to a temperature of 40 ° C.,
Injection was performed at an injection speed of 1.0 kg / min and an injection pressure of 600 kgf / cm 2 to form a molded product having a thick portion. As a result, "sink marks" were generated in the thick portion, and the surface appearance of the molded product was poor.
【００１８】比較例３ 実施例１の第１の金型と同様の金型を用いた。また、熱
可塑性樹脂は実施例１の第１の熱可塑性樹脂と同様のも
のを用いた。熱可塑性樹脂を金型キャビティ内にシリン
ダー温度２２０℃で、１．０ｋｇ／分の射出速度、６０
０ｋｇｆ／ｃｍ2 の射出圧力で射出した後、厚肉部に窒
素ガスを４０ｋｇｆ／ｃｍ2 で注入し、中空部を有する
成形品を成形した。この結果、厚肉部の“ヒケ”は改善
されたが、中空部周辺に光沢ムラが生じ、成形品の表面
外観が悪かった。 Comparative Example 3 A mold similar to the first mold of Example 1 was used. The same thermoplastic resin as the first thermoplastic resin of Example 1 was used. The thermoplastic resin is injected into the mold cavity at a cylinder temperature of 220 ° C. at an injection speed of 1.0 kg / min, 60
After injection at an injection pressure of 0 kgf / cm 2, the nitrogen gas in the thick portion was injected at 40 kgf / cm 2, and a molded article having a hollow portion. As a result, "thickness" of the thick portion was improved, but uneven gloss was generated around the hollow portion, and the surface appearance of the molded product was poor.
【００１９】実施例３ ＭＦＲが１５ｇ／１０分、曲げ弾性率が１００ｋｇｆ／
／ｃｍ2 であり、スチレン・イソプレン・スチレンブロ
ック共重合体の水素添加物（（株）クラレ製「セプトン
２００６Ｃ」）、パラフィン系オイル（出光興産
（株）製「ダイアナプロセスオイル ＰＷ３８０」）、
ポリプロピレン樹脂（三菱油化（株）製「三菱ポリプロ
ＴＡ３」）を３２：４８：２０の割合で二軸押出機で
混練したコンパウンドを用いた。実施例１と同様の金型
を用い、実施例１で用いたものと同じ第１の熱可塑性樹
脂を４０℃の温度に加熱した第１の金型キャビティ内に
シリンダー温度２２０℃で、１．０ｋｇ／分の射出速
度、６００ｋｇｆ／ｃｍ2 の射出圧力で射出し、中空部
を有する熱可塑性樹脂製基材を成形した。次に、基材を
第２の金型キャビティに設置した後、第２の熱可塑性樹
脂として、Ａ部シリンダー温度２２０℃で、１．０ｋｇ
／分の射出速度、６００ｋｇｆ／ｃｍ2 で射出し、成形
品を得た。この結果、厚肉部に光沢ムラが無く、ヒケも
無い、表面外観の良好な成形品が得られた。 Example 3 MFR of 15 g / 10 min, flexural modulus of 100 kgf /
/ Cm 2 , a hydrogenated product of a styrene / isoprene / styrene block copolymer (“Septon 2006C” manufactured by Kuraray Co., Ltd.), a paraffin oil (“Diana Process Oil PW380” manufactured by Idemitsu Kosan Co., Ltd.),
A compound obtained by kneading polypropylene resin (“Mitsubishi Polypro TA3” manufactured by Mitsubishi Petrochemical Co., Ltd.) at a ratio of 32:48:20 by a twin-screw extruder was used. Using a mold similar to that of Example 1, the same first thermoplastic resin as that used in Example 1 was heated to a temperature of 40 ° C. in a first mold cavity at a cylinder temperature of 220 ° C. Injection was performed at an injection speed of 0 kg / min and an injection pressure of 600 kgf / cm 2 , to mold a thermoplastic resin substrate having a hollow portion. Next, after the base material was placed in the second mold cavity, 1.0 kg was used as the second thermoplastic resin at the part A cylinder temperature of 220 ° C.
Injection was carried out at an injection speed of 600 kgf / cm 2 per minute to obtain a molded product. As a result, a molded product having a good surface appearance with no uneven gloss in the thick portion and no sink mark was obtained.
【００２０】実施例４ ＭＦＲが２ｇ／１０分、曲げ弾性率が６００ｋｇｆ／／
ｃｍ2 である、オレフィン系熱可塑性エラストマー（三
菱油化（株）製「サーモラン ３８０１Ｂ」）を、実施
例１と同様の金型を用い、実施例１で用いたものと同じ
第１の熱可塑性樹脂を４０℃の温度に加熱した第１の金
型キャビティ内にシリンダー温度２２０℃で、１．０ｋ
ｇ／分の射出速度、６００ｋｇｆ／ｃｍ2 の射出圧力で
射出し、中空部を有する熱可塑性樹脂製基材を成形し
た。次に、基材を第２の金型キャビティに設置した後、
第２の熱可塑性樹脂として、Ｂ部シリンダー温度２２０
℃で、１．０ｋｇ／分の射出速度、６００ｋｇｆ／ｃｍ
2 で射出し、成形品を得た。この結果、厚肉部に光沢ム
ラが無く、ヒケも無い、表面外観の良好な成形品が得ら
れた。 Example 4 MFR of 2 g / 10 minutes and flexural modulus of 600 kgf //
The same first thermoplastic resin as used in Example 1 was used for the olefinic thermoplastic elastomer (“Thermoran 3801B” manufactured by Mitsubishi Petrochemical Co., Ltd.) having a cm 2 of the same mold as in Example 1. 1.0k at a cylinder temperature of 220 ° C in the first mold cavity where the resin is heated to a temperature of 40 ° C.
Injection was performed at an injection speed of g / min and an injection pressure of 600 kgf / cm 2 , to mold a thermoplastic resin substrate having a hollow portion. Next, after placing the substrate in the second mold cavity,
As the second thermoplastic resin, the cylinder temperature of part B is 220
Injection rate of 1.0 kg / min at 600 ° C, 600 kgf / cm
Injection was performed at 2 to obtain a molded product. As a result, a molded product having a good surface appearance with no uneven gloss in the thick portion and no sink mark was obtained.
【００２１】実施例５ ＭＦＲが１１ｇ／１０分、曲げ弾性率が３，０００ｋｇ
ｆ／／ｃｍ2 である、オレフィン系熱可塑性エラストマ
ー（三菱油化（株）製「サーモラン ２３５０Ｂ」）
を、実施例１と同様の金型を用い、実施例１で用いたも
のと同じ第１の熱可塑性樹脂を４０℃の温度に加熱した
第１の金型キャビティ内にシリンダー温度２２０℃で、
１．０ｋｇ／分の射出速度、６００ｋｇｆ／ｃｍ2 の射
出圧力で射出し、中空部を有する熱可塑性樹脂製基材を
成形した。次に、基材を第２の金型キャビティに設置し
た後、第２の熱可塑性樹脂として、Ｃ部シリンダー温度
２２０℃で、１．０ｋｇ／分の射出速度、６００ｋｇｆ
／ｃｍ2 で射出し、成形品を得た。この結果、厚肉部に
光沢ムラが無く、ヒケも無い、表面外観の良好な成形品
が得られた。 Example 5 MFR of 11 g / 10 minutes and flexural modulus of 3,000 kg
f // cm 2 olefinic thermoplastic elastomer (“Thermoran 2350B” manufactured by Mitsubishi Petrochemical Co., Ltd.)
At a cylinder temperature of 220 ° C. in a first mold cavity obtained by heating the same first thermoplastic resin as used in Example 1 to a temperature of 40 ° C. using the same mold as in Example 1.
Injection was performed at an injection speed of 1.0 kg / min and an injection pressure of 600 kgf / cm 2 , to mold a thermoplastic resin base material having a hollow portion. Next, after the base material was placed in the second mold cavity, as the second thermoplastic resin, the C part cylinder temperature was 220 ° C., the injection speed was 1.0 kg / min, and the pressure was 600 kgf.
/ Cm 2 was injected to obtain a molded product. As a result, a molded product having a good surface appearance with no uneven gloss in the thick portion and no sink mark was obtained.
【００２２】[0022]
【表１】 [Table 1]
【００２３】[0023]
【表２】 [Table 2]
【００２４】[0024]
【発明の効果】本発明の厚肉部を有する樹脂成形品の射
出成形方法は、厚肉部にガスを注入することにより中空
化させて「ヒケ」の発生を防止すると共に、ガス注入に
より生じる光沢ムラを被覆材を積層することによって解
消する射出成形方法である。EFFECT OF THE INVENTION In the method of injection molding a resin molded product having a thick portion of the present invention, gas is injected into the thick portion to make it hollow so as to prevent the occurrence of "sink", and at the same time, it is caused by gas injection. It is an injection molding method that eliminates uneven gloss by laminating a coating material.
Claims (2)
基材を、該厚肉部にガスを注入して中空射出成形した
後、該厚肉部の突起部が存在する面と反対側の基材表面
上に熱可塑性樹脂製被覆材を射出成形して積層すること
を特徴とする、厚肉部を有する樹脂成形品の射出成形方
法。1. A surface of a base material made of a thermoplastic resin having a thick-walled portion, in which gas is injected into the thick-walled portion to perform hollow injection molding in a mold, and then a projection portion of the thick-walled portion is present. An injection molding method for a resin molded product having a thick wall portion, characterized in that a thermoplastic resin coating material is injection-molded and laminated on the surface of the base material on the opposite side.
した後、或いは、予め射出成形した熱可塑性樹脂製被覆
材を金型内にインサートした後、厚肉部を有する熱可塑
性樹脂製基材を、該熱可塑性樹脂製被覆材側に該熱可塑
性樹脂製基材の厚肉部の突起部が存在する面と反対側の
面を位置させて、該厚肉部にガスを注入して中空射出成
形して積層することを特徴とする、厚肉部を有する樹脂
成形品の射出成形方法。2. A thermoplastic resin having a thick portion after injection molding of a thermoplastic resin coating material in a mold, or after inserting a thermoplastic resin coating material pre-injected into the mold. The base material made of thermoplastic resin is positioned on the side of the thermoplastic resin covering material opposite to the surface of the thick part of the base material of the thermoplastic resin where the protrusions are present, and gas is injected into the thick part. Then, a method of injection-molding a resin molded product having a thick portion, characterized by performing hollow injection molding and laminating.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18362394A JPH0847940A (en) | 1994-08-04 | 1994-08-04 | Injection molding method for resin molding having thick-wall part |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18362394A JPH0847940A (en) | 1994-08-04 | 1994-08-04 | Injection molding method for resin molding having thick-wall part |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0847940A true JPH0847940A (en) | 1996-02-20 |
Family
ID=16139018
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18362394A Pending JPH0847940A (en) | 1994-08-04 | 1994-08-04 | Injection molding method for resin molding having thick-wall part |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0847940A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999003665A1 (en) * | 1997-07-15 | 1999-01-28 | Gas Injection Limited | Improvements in or relating to gas assisted injection moulding |
| WO1999037459A1 (en) * | 1998-01-21 | 1999-07-29 | Selle Royal S.P.A. | Method for multiple-injection-molding of plastic materials for manufacturing integral elastic supports and elastic supports manufactured with this method |
| JP2008290395A (en) * | 2007-05-25 | 2008-12-04 | Panasonic Electric Works Co Ltd | Method for forming two-color molding |
-
1994
- 1994-08-04 JP JP18362394A patent/JPH0847940A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999003665A1 (en) * | 1997-07-15 | 1999-01-28 | Gas Injection Limited | Improvements in or relating to gas assisted injection moulding |
| WO1999037459A1 (en) * | 1998-01-21 | 1999-07-29 | Selle Royal S.P.A. | Method for multiple-injection-molding of plastic materials for manufacturing integral elastic supports and elastic supports manufactured with this method |
| JP2008290395A (en) * | 2007-05-25 | 2008-12-04 | Panasonic Electric Works Co Ltd | Method for forming two-color molding |
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