JP2004136536A

JP2004136536A - Mold for in-mold coating molding

Info

Publication number: JP2004136536A
Application number: JP2002303023A
Authority: JP
Inventors: Etsuo Okahara; 岡原　悦雄
Original assignee: Ube Machinery Corp Ltd
Current assignee: Ube Machinery Corp Ltd
Priority date: 2002-10-17
Filing date: 2002-10-17
Publication date: 2004-05-13
Anticipated expiration: 2022-10-17
Also published as: JP3925386B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for in-mold coating molding for controlling a fluidized state of a coating material in a mold cavity to set the fluidizing terminal of the coating material to a part exerting no effect on appearance. <P>SOLUTION: A projection or a movable piece for controlling the fluidizing terminal of the coating material is arranged to the surface of the mold cavity and controlled so that the fluidizing terminal of the coating material becomes a part exerting no effect on the appearance. For example, a projection is arranged to the surface of the mold cavity on a coating material injection side at a part where the surface parts of opposed resin molded products exert no effect on the quality of the appearance of the molded product. The height of the projection is formed so as to become larger than the thickness of a coating while at least a part of the side surface of the projection is formed so as to be inclined in a mold on-off direction and the filling of the surface part of the resin molded product opposed to the projection with the coating material is dilayed to perform control so that the fluidizing terminal of the coating material becomes a part exerting no effect on the appearance of the resin molded product. By this constitution, the good resin molded product can be obtained. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、金型内で樹脂を成形した後、樹脂成形品と金型キャビティ面との間に塗料を注入して硬化させることによって、表面を塗料により被覆（塗膜と称することもある）した成形品を成形するに好適な型内被覆成形用金型に関する。
【０００２】
【従来技術】
従来から、熱可塑性樹脂を基材とした樹脂成形品の装飾性を高める方法として、塗装法による加飾が多く用いられている。
従来から行われている塗装法は、金型内で射出成形した成形品を該金型から取り出した後、スプレー法や浸漬法等により、成形品の表面に塗料の塗布を行うことが一般的であり、塗布された塗料はその後、硬化することによって、強固な塗膜となって成形品の表面を被覆し、該表面を加飾するとともに保護する。
【０００３】
しかしながら、近年においては前記塗装方法による工程の省略化を目的とし、樹脂の成形と塗膜による被覆を同一の金型内で行う型内被覆成形方法（インモールドコーティング方法と称されることもある）が提案されている。
【０００４】
前記型内被覆成形方法の一例として、図７にそのフローチャートの概略を示す。図７に示した従来の型内被覆成形方法は、熱可塑性樹脂を基材として金型内で射出成形した後、金型をわずかに開いた状態として型内で成形した樹脂成形品と金型キャビティ面との間に隙間を生じさせ、該隙間に塗料注入機を使用して塗料を注入する。
その後、金型を再度型締することによって成形品の表面に塗料を均一に拡張させた後、硬化させて被覆することを特徴とした型内被覆成形方法である。
【０００５】
前記型内被覆成形方法によれば、熱可塑性樹脂の成形と被覆を同一の金型内で行うため、工程の省略化によるコストダウンが可能であると同時に、浮遊している塵が硬化する以前の塗膜に付着して不良となる等といったことがほとんどなく、高い品質の製品を得ることができる。そのため、特に、外観に対して高い品質が要求される自動車用の部品、例えば、バンパー、ドア、ドアミラーカバー、フェンダー等多くの部品には、前記型内被覆成形方法の利用が検討されている。
【０００６】
前記型内被覆成形方法に用いることのできる金型としては、特許文献１、あるいは特許文献２にその例を示めされるように、金型キャビティの外に塗料が漏れ出すことを防止するための型内被覆成形用金型が数多く提案されている。
【０００７】
【特許文献１】
特開２００２−１２７１９８号公報
【特許文献２】
特開２００２−１２７１９９号公報
【０００８】
【発明が解決しようとする課題】
【０００９】
しかしながら、前記型内被覆成形方法に用いる塗料として、アルミ紛等といった光輝材料を含有させた所謂メタリック塗料、あるいはマイカ紛等といった光輝材料を含有させた所謂メタリック調塗料が選択されることは極めて少ない。
というのは、注入した塗料の流動末端で、塗料中の光輝顔料が配向ムラを起こして外観不良になるといった問題が発生するからである。
前記流動末端となる金型キャビティ部分に、捨てキャビティを形成する等の対策を施すことによって前記問題の発生を防止することも可能であるが、捨てキャビティに充填された樹脂と塗料を、成形後に切除する必要が発生して、成形効率が悪くなる。
【００１０】
型内被覆成形方法で成形される成形品の多くは、外観に影響を与えない部分を有しており、被覆の必要がない部分を有している。塗料の流動末端が、外観に影響を与えない部分となるよう金型キャビティを設計できれば、前記光輝材料の配向ムラで発生する成形品の外観不良を防止することができる。しかし、成形品の形状によっては、成形品の外観に影響を与えない部分に塗料の流動末端をもっていくことが極めて困難である。
【００１１】
本発明は、上記問題点に鑑みてなされたものであり、金型キャビティ内で塗料の流動状態を制御して、塗料の流動末端を外観に影響を与えない部分とする型内被覆成形用金型を提供するものである。
【００１２】
【課題を解決するための手段】
上記の課題を解決するため、本発明による型内被覆成形用金型は、
（１）　　雄型と雌型により形成した金型キャビティを有し、該金型キャビティで成形した樹脂成形品の表面に該金型キャビティ内で被覆を施すための塗料注入機を備えた型内被覆成形用金型において、塗料を注入する側の金型キャビティ面で、対向する樹脂成形品の表面部分が成形品外観の良否に影響を与えない部分に凸部を配設し、該凸部の高さを前記被覆の厚みより大きく形成するとともに、該凸部の側面の少なくとも一部を型開閉方向に対して傾斜させて形成することによって、該凸部に対向する脂成形品の表面部分への塗料充填を遅延させて塗料流動末端の位置を制御する構成とした。
【００１３】
（２）（１）に記載の型内被覆成形用金型において、前記凸部に対向する金型キャビティ面に、該凸部の少なくとも一部を挿脱できる凹部を形成した。
【００１４】
（３）　雄型と雌型により形成した金型キャビティを有し、該金型キャビティで成形した樹脂成形品の表面に該金型キャビティ内で被覆を施すための塗料注入機を備えた型内被覆成形用金型において、塗料を注入する側の金型キャビティ面で、対向する樹脂成形品の表面部分が成形品外観の良否に影響を与えない部分に凸部を配設し、該凸部の型開閉方向の高さを部分的に異ならせて、前記被覆の厚みより小さな部分と大きな部分とを形成することよって、該凸部に対向する脂成形品の表面部分への塗料充填を遅延させて塗料流動末端の位置を制御する構成とした。
【００１５】
（４）　雄型と雌型により形成した金型キャビティを有し、該金型キャビティで成形した樹脂成形品の表面に該金型キャビティ内で被覆を施すための塗料注入機を備えた型内被覆成形用金型において、塗料を注入しない側の金型キャビティ面で、対向する金型キャビティ面で成形される樹脂成形品の表面部分が成形品外観の良否に影響を与えない部分に溝部を形成して、該溝部の金型キャビティ側形状に略一致する形状で該溝部の中を金型型開閉方向に摺動できる可動駒を該溝部に配するとともに、該可動駒を開閉方向に移動させる駆動機構を備えて、該可動駒を金型キャビティ内に前後進できる構成とすることにより、該可動駒に対向する位置にある樹脂成形品の費用面部分を塗料を注入する側の金型キャビティ面へ押しつけて塗料の流れを規制することによって塗料流動末端の位置を制御する構成とした。
【００１６】
（５）　雄型と雌型により形成した金型キャビティを有し、該金型キャビティで成形した樹脂成形品の表面に該金型キャビティ内で被覆を施すための塗料注入機を備えた型内被覆成形用金型において、塗料を注入する側の金型キャビティ面で、対向する樹脂成形品の表面部分が成形品外観の良否に影響を与えない部分に溝部を形成して、該溝部の金型キャビティ側形状に略一致する形状で該溝部の中を金型型開閉方向に摺動できる可動駒を該溝部に配するとともに、該可動駒を開閉方向に移動させる駆動機構を配して、該可動駒が金型キャビティ内に前後進できる構成とすることにより、該可動駒と該可動駒に対向する位置にある樹脂成形品への塗料充填を遅延させて塗料流動末端の位置を制御する構成とした。
【００１７】
【発明の実施の形態】
以下、図面に基づいて本発明による型内被覆成形用金型の実施形態について説明する。図１〜図５は本発明の実施形態に係わり、図１は型内被覆成形用金型の構成を説明するため概略の構造を示した構造図であり、図２は型内被覆成形用金型に配した凸部の形状を説明するための説明図である。図３は凸部近傍付近の樹脂の充填状態と被覆の状態を説明するための概念図であって、図４は金型内における塗料の流動状態を説明するための図である。図５は他の実施形態による型内被覆成形用金型に配した凸部、又は可動駒を説明するための概念図である。図６は従来法と比較例による金型内の塗料流動状態を説明するための図である。図７は従来法による型内被覆成形方法の工程を説明するフローチャートである。
【００１８】
本発明に係わる型内被覆成形用金型１００（金型１００と称することもある）の好ましい１例について、以下その構造を図１〜図４を用いて詳細に説明する。本発明による金型１００は、可動型１０、固定型２０、凸部１、及塗料注入機５０を備えている。なお、図１に示した実施形態の１例においては、可動型１０が雌型であり、固定型２０が雄型である。
【００１９】
金型１００は、雄型である固定型２０と雌型である可動型１０とがくいきり構造の嵌合部で嵌め合わされ、該嵌め合わされた状態でその内部に金型キャビティ１５を形成する構造となっており、該くいきり構造の嵌合部（くいきり部と称することもある）は金型キャビティ１５の全周にわたって形成される。
そして、金型１００はくいきり部にて金型キャビティ１５に充填した樹脂が、金型１００から漏れ出すことを防止することができる。
【００２０】
次ぎに、図１に示した凸部１の配置と形状についてその詳細を説明する。
図１に示した金型１００で成形される成形品は、図４にその概略形状を示したように長方形の平板状であって、その一旦側に塗料注入口５１を形成している。
【００２１】
通常、このような形状の型内被覆成形品を成形する場合は、図６（１）に示すように、塗料の流動末端が、塗料注入口５１を配した側と反対側の端の隅部Ｋの部分に形成される。前述したような光輝材料を含有させた塗料を用いると、塗料の流動末端となる隅部Ｋにおいては、塗料中の光輝顔料が配向して外観不良になる。
【００２２】
そのため、図１に示した金型１００は、塗料注入側の金型である可動型１０の金型キャビティ面で、対向する樹脂成形品の表面部分が成形品外観の良否に影響を与えない部分に凸部１を形成し、凸部１の高さＨを後述の工程で成形品表面を被覆する被覆の厚みより大きく形成するとともに、凸部１の側面の少なくとも一部を型開閉方向に対して傾斜させて形成した。
【００２３】
凸部１に傾斜面を形成した理由を説明する。
傾斜面を形成した凸部１近傍に対して図３（２）に示すように樹脂を充填した後、金型１００をわずかに開いて樹脂成形品と可動型１０の金型キャビティ面との間に塗料を注入するための空隙（隙間と称することもある）を形成した場合に、該空隙の大きさは、型開閉方向に対して直交する方向とそうでない方向で異なる。
【００２４】
つまり、図３（３）に記載した空隙の厚みは、型開閉方向に対して直交する面の部分に形成される空隙の厚みＴ１が最も大きく、凸部１の側面で型開閉方向にして平行な部分に形成される空隙の厚みＴ２が最も小さい。そして、前記傾斜面に形成される空隙の厚みＴ３は、前記厚みＴ１とＴ２との間の厚みとなる。
特に、凸部１の側面で型開閉方向にして平行な部分に形成される空隙の厚みＴ２は樹脂成形品の冷却による収縮分しかないことから、非常に小さな厚みとなる。
【００２５】
後述する塗料注入と型締工程で、樹脂成形品の表面を塗料が流動するが、図４に示したように、金型キャビティ１５内の空隙を進んで凸部１に達した塗料は、空隙Ｔ１の方向から凸部１に流れ込まず、最も大きな空隙であるＴ１の部分を優先的に流れて、比較的空隙の大きなＴ３の方向から図３（３）に示した凸部１の空隙Ｍに流れ込むことになる。そのため、凸部１の端面側に形成された空隙Ｍに塗料が流入するタイミングが遅延する。
【００２６】
従って、凸部１を形成するに好ましい位置は、成形品の外観に影響を与えない金型キャビティ部分で、凸部１を形成しない場合に塗料流動末端が形成される部分にできるだけ近い位置である。また、凸部１の流動末端に近い方の側面に傾斜面を形成することが好ましい。
前記構成の凸部１によれば、塗料注入口５１側から流動してきた塗料は、凸部１に到達した後、凸部１を迂回するようにして流れ、塗料流動末端側に形成した傾斜面側から凸部１の空隙Ｍに流れ込む。
そして、前記構成によって、凸部１の空隙Ｍに塗料が流れ込むタイミングを、効果的に遅延させることが可能である。
【００２７】
また、成形品によって外観に影響を与えない金型キャビティ部分の位置は異なるが、傾斜面の角度等を調整することにより、凸部１に流れ込む塗料のタイミングを調整することが可能である。
例えば、図２（３）に示した傾斜の角度θを小さくして型開閉方向に対して平行な方向に近づけると、空隙の厚みＴ２の大きさは小さくなるため塗料が空隙Ｍに流れ込みにくくなり、凸部１の空隙Ｍに塗料が流れ込むタイミングが大きく遅延する。
【００２８】
また、傾斜の角度θを大きくして型開閉方向に対して直交する方向に近づけると、空隙の厚みＴ２の大きさは大きくなるので、塗料が空隙Ｍに流れ込み易くなり、空隙Ｍに塗料が流れ込むタイミングを遅延させる効果が小さくなる。
前記凸部１の配置と傾斜面の角度θ等を調整して、塗料の流動末端を、前記隅部Ｋより凸部１の空隙Ｍ、あるいは、その他の外観に影響を与えない金型キャビティ部分の位置に変化させることによって、良好な成形品を得ることが可能である。
【００２９】
比較として、傾斜面を形成しない凸部２００を図１に配した場合を説明すると、凸部２００の高さが被覆の厚みより小さい場合は、図４（２）に示したように、塗料が凸部２００の端面側に形成された空隙を迂回することなく素通りすることになり、凸部２００に塗料が流れ込むタイミングを遅延させる効果はほとんど期待できない。また、凸部２００の高さを前記被覆の厚みより大きく形成した場合は、凸部２００に対向する部分に樹脂が流れ込むことができないので、塗料が凸部２００を迂回して流れるだけとなり、端面側の空隙部分に流れ込むことができなくなる。
【００３０】
また、凸部１を形成したことにより、金型キャビティ１５内に狭い部分が形成されると、樹脂の充填工程において樹脂流動が大きく変化する場合がある。
図１に示した実施形態においては、凸部１と対向する位置に凹部３を形成することによって、金型キャビティ１５内にできるだけ狭い部分ができないよう構成した。
【００３１】
次に、塗料注入機５０について簡単に説明する。
本実施の形態における塗料注入機５０は、可動型１０に取り付けられて、可動型１０の金型キャビティ面に配設された塗料注入口５１より金型キャビティ１５内に塗料を注入することができるよう構成されている。
また、塗料注入機５０の塗料注入口５１には図示しないバルブが取りつけられており、基材の射出成形時においては、該バルブが閉じられていることによって、金型１００の金型キャビティ１５内に射出された樹脂が塗料注入口５１より塗料注入機５０内に進入することを防止している。
【００３２】
そして、本実施の形態における塗料注入機５０は、図示しない駆動装置によって駆動されて、塗料注入機５０の中に供給された塗料を、所望する量だけ正確に可動型１０の金型キャビティ面より注入することができるよう構成されている。
【００３３】
なお、本実施の形態における塗料注入機５０は、前記したように可動型１０の金型キャビティ面より塗料を注入するよう構成したが、これに限るものではなく、金型キャビティ１５内で成形した樹脂成形品と金型キャビティ面との間に生じた隙間部分に塗料を注入できるように構成すれば良く、その条件を満たせば塗料注入機５０は固定型２０に取りつけられる等しても良い。
【００３４】
以下、金型１００を用いた型内被覆成形方法を説明する。
まず、第１の工程として、図示しない型締装置により金型１００を型締めする。この状態において、金型キャビティ１５内の凸部１の近傍は図３（１）に示すようになっている。そして、図３（２）に示したように基材である熱可塑性樹脂を金型内に射出（本実施の形態においては、基材としてＡＢＳ樹脂：宇部サイコン株式会社製　ＵＴ２０Ｂ）する。
【００３５】
その後、基材をある程度（後述する塗料の注入圧力に耐えうる程度）まで冷却させる。基材の冷却後、図３（３）に示すように金型をわずかに開いた状態（本実施の形態においては１ｍｍほど型開方向に可動型１０を移動させた状態）として、金型キャビティ１５内で成形した樹脂成形品と可動型１０の金型キャビティ面との間に空隙（隙間と称することもある）を生じさせる。
【００３６】
前述したように金型１００をわずかに開いて樹脂成形品と可動型１０の金型キャビティ面との間に塗料を注入するための空隙を形成した場合、該空隙の大きさは、型開閉方向に対して直交する方向とそうでない方向で異なる。
図３（４）に記載した空隙の厚みは、型開閉方向に対して直交する方向側の空隙の厚みＴ１（本実施形態においては１ｍｍ）が最も大きく、型開閉方向側の空隙の厚みＴ２（本実施形態においては樹脂の収縮分相当）が最も小さい。
また、傾斜面側の空隙の厚みＴ３は、前記厚みＴ１とＴ２との間の厚み（本実施形態においては、傾斜角度θを４５度として厚みＴ３は０．７ｍｍ）となる。
【００３７】
前記隙間を生じさせた後、塗料注入機５０によって塗料注入口５１から前記隙間に対して塗料を２５ｍｌ（ミリリットル）注入する。なお、本実施形態に用いた金型で成形する成形品の被覆表面積は２５００ｃｍ^２であり、塗膜の厚みは０．１ｍｍ程度となる。
また、本実施の形態において用いた塗料は、プラグラス＃８０００：シルバーメタリック（大日本塗料株式会社製）である。
【００３８】
塗料を注入した後、可動型１０を固定型２０の方向に移動させ金型１００を再度閉じて型締めすることにより、隙間の中の塗料を押し広げながら流動させ、成形品表面を塗料で被覆する。
【００３９】
その際において、図４に示したように、金型キャビティ１５内の空隙を進んで凸部１に達した塗料は、空隙Ｔ１の方向から凸部１に流れ込まず、最も大きな空隙であるＴ１の部分を優先的に流れて、比較的空隙の大きなＴ３の方向から凸部に流れ込むことにより、塗料の凸部１に流入するタイミングが遅延して、塗料の流動末端は、前記隅部Ｋより凸部１の位置に変化する。
そして、金型１００の金型キャビティ１５内の被覆領域の隅々まで塗料が行き渡ったと同時に圧力をかけたままの状態とする。
【００４０】
なお、隅部Ｋに達した塗料はそこで一旦流動が停止して配向ムラが発生するがその後、凸部１に塗料が流れ込む際に、わずかに塗料が再流動することにより、発生した配向ムラが解消して良好な被覆表面となる。
樹脂を成形する場合においては、スキン層の樹脂が冷却固化して流動を停止しているため、内部の樹脂が再流動してもスキン層は再流動しないので配向ムラは解消しないが、塗料では成形時にスキン層の形成がほとんどないので、再流動させることによって配向ムラが解消する。
以上の工程で、塗料の流動末端を外観に影響を与えない部分とすることにより、外観不良のない良好な型内被覆成形品を得ることができた。
【００４１】
次ぎに他の実施形態を、先に説明した実施形態と異なっている部分についてのみ説明する。
【００４２】
図５（１）に示す実施形態においては、塗料を注入する側の金型キャビティ面で、対向する樹脂成形品の表面部分が成形品外観の良否に影響を与えない部分に被覆の厚みより小さな部分と大きな部分とを有した凸部１Ａを形成している。
凸部１Ａを、Ａ−Ａ方向から見た場合、矩形の枠状であって、塗料注入口５１の方向側に被覆の厚みより大きな部分Ｌ１を形成し、凸部１Ａを形成しない場合に塗料流動末端が形成される側に被覆の厚みより小さな部分Ｌ２を形成する。
【００４３】
塗料注入の際において、図５（１）に示したように金型キャビティ１５内の空隙を進んで凸部１Ａの被覆の厚みより大きな部分に達した塗料は、凸部１ＡのＬ１側から凸部１Ａの枠内に流れ込まず、比較的空隙の大きい凸部１ＡのＬ２側から流れ込む。そのため、凸部１の枠内に塗料が流入するタイミングが遅延して、塗料の流動末端の位置が変化する。
図５（１）に示す実施形態の金型を用いた場合、前述の実施形態と同様に塗料が流れて、隅部Ｋに達した塗料はそこで一旦流動が停止して配向ムラが発生するがその後、該隙間に塗料が流れ込む際において、わずかに塗料が再流動することによって、発生した配向ムラが解消して良好な被覆表面となる。
【００４４】
次ぎに、油圧シリンダ駆動方式の可動駒を備えた型内被覆成形用金型の詳細を図５（２）を用いて説明する。
図５（２）に用いた実施形態は、前記雄型と雌型のどちらか一方で塗料を注入しない側の金型キャビティ面で成形品の外観に影響を与えない部分に溝部を形成して、該溝部の金型キャビティ側形状に略一致する形状で該溝部の中を金型型開閉方向に摺動できる可動駒１Ｂを該溝部に配する。
また、可動駒１Ｂを型開閉方向に移動させる駆動機構を備えて、可動駒１Ｂが金型キャビティ内に前後進できる構成とすることによって、可動駒１Ｂに対向する位置にある樹脂成形品を押さえて塗料を注入する側の金型キャビティ面へ押しつけることにより、塗料の流れを規制して、塗料の流動状態を制御する。
【００４５】
可動駒１Ｂの挙動と塗料の流動状況を説明する。
まず、第１の工程として、図示しない型締装置により金型１００を型締めする。この状態において、可動駒１Ｂは、押圧機構で油圧シリンダに制御されて、可動駒１Ｂのキャビティ側端面と金型キャビティ面とが同一平面状に配置された状態となっている。
【００４６】
そして、基材である熱可塑性樹脂を金型内に射出（先の実施の形態と同様に、基材としてＡＢＳ樹脂：宇部サイコン株式会社製　ＵＴ２０Ｂ）する。その後、基材をある程度まで冷却させる。
基材の冷却後、金型をわずかに開いた状態として、金型キャビティ１５内で成形した樹脂成形品と可動型１０の金型キャビティ面との間に隙間を生じさせる。
【００４７】
隙間を生じさせた後、油圧シリンダを作動させて、可動駒１Ｂをキャビティ側に移動させることにより、可動駒１Ｂの一端を樹脂成形品に当接させた状態とし、樹脂成形品を可動型１０の金型キャビティ面に強く押しつけた状態として、表１の塗料を注入する。金型キャビティ面に樹脂成形品を押しつけた部分には、塗料が流動して流れることができない堰となる。従って、塗料は、前記樹脂成形品を押しつけた部分を迂回して流れる。
【００４８】
そして、塗料を注入した後、可動型１０を固定型２０の方向に移動させ金型１００を再度閉じて型締めすることによって、隙間の中の塗料を押し広げながら流動させ、金型１００の金型キャビティ１５内の被覆領域の隅々まで行き渡らせると同時に圧力をかけたままの状態とする。なお、油圧シリンダに押圧された可動駒１Ｂは、金型の型締めに伴って成形品に当接したままの状態で徐々に反キャビティ側に移動するようその油圧を調整しておく。そして、塗料が前記押しつけた部分以外の隅々に行き渡った時点で、油圧シリンダを駆動して、可動駒１Ｂを反キャビティ側に移動させて、可動駒１Ｂのキャビティ側端面と金型キャビティ面とが同一平面状に配置された状態とする。
【００４９】
可動駒１Ａのキャビティ側端面と金型キャビティ面とが同一平面状に配置された状態となった時点で、金型キャビティ面に樹脂成形品を押しつけた部分が離れるので隙間が形成され、該隙間部分に塗料が流動して流れ込み、該隙間部分に塗料流動末端を形成する。
隅部Ｋに達した塗料はそこで一旦流動が停止して配向ムラが発生するがその後、該隙間に塗料が流れ込む際において、わずかに塗料が再流動することによって、発生した配向ムラが解消して良好な被覆表面となる。
【００５０】
なお、本発明に使用できる押圧機構は、前述した油圧シリンダに限らず、空圧シリンダであっても良く。また電磁石を使用して可動駒１Ｂを可動型１０に引っ張るような方式のものであっても良い。
また、図５（２）に示す実施形態の型内被覆成形用金型であれば、前記隙間に流れ込む塗料のタイミングを駆動機構の動作タイミングにて、制御できる。従って、塗料注入タイミングの遅延を効果を自在に制御できるという点で非常に好ましい形態であり、適用できる成形品の範囲が広いという優れた効果を有する。
【００５１】
次ぎに、図５（３）に用いた実施形態は、前記雄型と雌型のどちらか一方で塗料を注入する側の金型キャビティ面で金型キャビティ面で成形品の外観に影響を与えない部分に溝部を形成して、該溝部の金型キャビティ側形状に略一致する形状で該溝部の中を金型型開閉方向に摺動できる可動駒１Ｃを該溝部に配する。
また、該可動駒１Ｃを開閉方向に移動させる駆動機構を備えて、該可動駒１Ｃが金型キャビティ内に前後進できる構成とすることにより、可動駒１Ｃに対向する位置にある樹脂成形品を塗料を注入する側の金型キャビティ面へ押しつけて塗料の流れを規制することによって、塗料の流動状態を制御する。
【００５２】
可動駒１Ｃの挙動と塗料の流動状況を説明する。
まず、第１の工程として、図示しない型締装置により金型１００を型締めする。この状態において、可動駒１Ｂは、油圧シリンダに制御されて、可動駒１Ａのキャビティ側端面と金型キャビティ面とが同一平面状に配置された状態となっている。
【００５３】
そして、基材である熱可塑性樹脂を金型内に射出する。その後、基材をある程度まで冷却させる。
基材の冷却後、金型をわずかに開いた状態として、金型キャビティ１５内で成形した樹脂成形品と可動型１０の金型キャビティ面との間に隙間を生じさせる。
【００５４】
隙間を生じさせた後、油圧シリンダを作動させて、可動駒１Ｃをキャビティ側に移動させることにより、可動駒１Ｃの一端を樹脂成形品に当接させた状態とし、表１の塗料を注入する。
【００５５】
樹脂成形品に可動駒１Ｃを押しつけた部分は、塗料が流動して流れることができない堰となる。従って、塗料は、可動駒１Ｃを押しつけた部分を迂回して流れる。塗料を注入した後、可動型１０を固定型２０の方向に移動させ、金型１００を再度閉じて型締めすることによって、隙間の中の塗料を押し広げながら流動させ、金型１００の金型キャビティ１５内の被覆領域の隅々まで行き渡らせると同時に圧力をかけたままの状態とする。
【００５６】
なお、油圧シリンダに押圧された可動駒１Ｃは、成形品に当接したままの状態で金型の型締めに伴って徐々に反キャビティ側に移動するようその油圧を調整しておく。そして、塗料が前記押しつけた部分以外の隅々に行き渡った時点で、油圧シリンダを駆動して、可動駒１Ｃを反キャビティ側に移動させて、可動駒１Ｃのキャビティ側端面と金型キャビティ面とが同一平面状に配置された状態とする。
【００５７】
可動駒１Ｃのキャビティ側端面と金型キャビティ面とが同一平面状に配置された状態となった時点で、可動駒１Ｃを樹脂成形品に押しつけた部分が離れて隙間が形成され、該隙間部分に塗料が流動して流れ込み、該隙間部分に塗料流動末端を形成する。
隅部Ｋに達した塗料はそこで一旦流動が停止して配向ムラが発生するがその後、該隙間に塗料が流れ込む際において、わずかに塗料が再流動することによって、発生した配向ムラが解消して良好な被覆表面となる。
【００５８】
図５（４）に示す実施形態の型内被覆成形用金型であれば、図５（３）に示した実施形態と同様に、前記隙間に流れ込む塗料のタイミングを駆動機構の動作タイミングにて、制御できる。従って、塗料注入タイミングの遅延を効果を自在に制御できるという点で非常に好ましい形態であり、適用できる成形品の範囲が広いという優れた効果を有する。
【００５９】
【発明の効果】
本発明においては、塗料流動末端が成形品の外観に影響を与えない部分になるよう制御することによって、良好な成形品を得るという優れた効果を得ることができる。
【００６０】
第１、３の発明においては、塗料を注入する側の金型キャビティ面で、対向する樹脂成形品の表面部分が成形品外観の良否に影響を与えない部分に凸部を配設し、該凸部の形状効果によって、凸部端面側に塗料が流入するタイミングを遅延させて、塗料の流動末端が成形品の外観に影響を与えない部分となるよう制御することにより、良好な成形品を得るという優れた効果を得る。
【００６１】
また、第２の発明においては、前記凸部に対向する位置に凹部を形成することによって、凸部により発生する可能性のある樹脂の流動不良を防止できる。
【００６２】
第４、５の発明においては、駆動装置により金型キャビティに対して前後進する可動駒を用いて、塗料が流れる隙間を局所的に規制して、塗料の流動末端が成形品の外観に影響を与えない部分にとなるよう制御することにより、良好な成形品を得るという優れた効果を得る。
【図面の簡単な説明】
【図１】本発明の実施形態に係わる型内被覆成形用金型の構成を説明するため概略の構造を示した構造図である。
【図２】本発明の実施形態に係わる型内被覆成形用金型に配した凸部の形状を説明するための説明図である。
【図３】本発明の実施形態に係わる型内被覆成形用金型の凸部近傍付近の樹脂の充填状態と被覆の状態を説明するための概念図である。
【図４】本発明の実施形態に係わる型内被覆成形用金型の塗料流動状態を説明するための図である。
【図５】本発明による他の実施形態の型内被覆成形用金型に配した凸部、又は可動駒を説明するための概念図である。
【図６】従来法と比較例による金型の塗料流動状態を説明するための図である。
【図７】従来法による型内被覆成形方法の工程を説明するフローチャートである。
【符号の説明】
１　　　凸部
１Ａ　　凸部
１Ｂ　　可動駒
１Ｃ　　可動駒
３　　　凹部
５　　　溝部
７　　　油圧シリンダ（押圧機構）
１５　　金型キャビティ
１０　　可動型
２０　　固定型
５０　　塗料注入機
５１　　塗料注入口
１００　型内被覆成形用金型
Ｋ　　　隅部[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, after a resin is molded in a mold, a paint is injected between the resin molded product and the cavity surface of the mold and cured to cover the surface with the paint (sometimes referred to as a coating film). The present invention relates to an in-mold coating forming die suitable for forming a molded product.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a method of improving the decorativeness of a resin molded product using a thermoplastic resin as a base material, decoration by a coating method is often used.
Conventional coating methods generally involve applying a paint to the surface of a molded article by spraying, dipping, or the like after removing the molded article obtained by injection molding in the mold from the mold. Then, the applied coating material is cured to form a strong coating film, which covers the surface of the molded article, and decorates and protects the surface.
[0003]
However, in recent years, for the purpose of omitting the steps by the coating method, in-mold coating forming method in which resin molding and coating with a coating film are performed in the same mold (sometimes referred to as an in-mold coating method). ) Has been proposed.
[0004]
As an example of the in-mold coating molding method, FIG. 7 shows a schematic flowchart thereof. In the conventional in-mold coating molding method shown in FIG. 7, a resin molded product and a mold are formed by injection molding in a mold using a thermoplastic resin as a base material, and then molding the mold with the mold slightly opened. A gap is formed between the cavity and the cavity surface, and the paint is injected into the gap using a paint injector.
Thereafter, the coating is uniformly spread on the surface of the molded article by re-clamping the mold, and then cured and coated to form an in-mold coating.
[0005]
According to the in-mold coating molding method, since the molding and coating of the thermoplastic resin are performed in the same mold, it is possible to reduce the cost by omitting the steps and at the same time before the floating dust is cured. It is possible to obtain a high-quality product with almost no occurrence of defects such as adhesion to the coating film. Therefore, the use of the in-mold coating forming method has been studied particularly for automobile parts requiring high quality in appearance, such as bumpers, doors, door mirror covers, and fenders.
[0006]
As a mold that can be used in the in-mold coating molding method, as shown in Patent Document 1 or Patent Document 2, examples thereof are for preventing paint from leaking out of a mold cavity. Many molds for in-mold coating molding have been proposed.
[0007]
[Patent Document 1]
JP-A-2002-127198
[Patent Document 2]
JP-A-2002-127199
[0008]
[Problems to be solved by the invention]
[0009]
However, as a paint used in the in-mold coating molding method, a so-called metallic paint containing a glitter material such as aluminum powder or a so-called metallic paint containing a glitter material such as mica powder is rarely selected. .
This is because, at the flow end of the injected paint, a problem arises in that the glittering pigment in the paint causes uneven alignment and poor appearance.
It is also possible to prevent the above-mentioned problem from occurring by taking measures such as forming a disposal cavity in the mold cavity portion serving as the flow end, but the resin and paint filled in the disposal cavity are formed after molding. The necessity of excision occurs, resulting in poor molding efficiency.
[0010]
Many of the molded articles molded by the in-mold coating molding method have portions that do not affect the appearance, and have portions that do not require coating. If the mold cavity can be designed so that the flow end of the paint does not affect the appearance, it is possible to prevent poor appearance of the molded product caused by the uneven orientation of the glittering material. However, depending on the shape of the molded article, it is extremely difficult to bring the flow end of the paint to a portion that does not affect the appearance of the molded article.
[0011]
The present invention has been made in view of the above problems, and controls the flow state of a paint in a mold cavity so that a flowing end of the paint does not affect the appearance. Provides a type.
[0012]
[Means for Solving the Problems]
In order to solve the above problems, the mold for in-mold coating molding according to the present invention,
(1) In a mold having a mold cavity formed by a male mold and a female mold, and having a paint injecting machine for coating the surface of a resin molded product molded in the mold cavity in the mold cavity. In the coating molding die, a convex portion is provided on a portion of the mold cavity on the side where the paint is injected, where a surface portion of the opposing resin molded product does not affect the appearance of the molded product. Is formed to be larger than the thickness of the coating, and at least a part of the side surface of the convex portion is formed to be inclined with respect to the mold opening / closing direction, so that the surface portion of the fat molded article facing the convex portion In this configuration, the position of the paint flow end is controlled by delaying the filling of the paint.
[0013]
(2) In the mold for in-mold coating molding described in (1), a concave portion through which at least a part of the convex portion can be inserted and removed is formed on a mold cavity surface facing the convex portion.
[0014]
(3) In a mold having a mold cavity formed by a male mold and a female mold, and having a paint injecting machine for coating the surface of a resin molded product molded in the mold cavity in the mold cavity. In the coating molding die, a convex portion is provided on a portion of the mold cavity on the side where the paint is injected, where a surface portion of the opposing resin molded product does not affect the appearance of the molded product. The height of the mold in the opening and closing direction is partially changed to form a portion smaller than the thickness of the coating and a portion larger than the thickness of the coating. Thus, the position of the paint flow end is controlled.
[0015]
(4) In a mold having a mold cavity formed by a male mold and a female mold, and having a paint injection machine for applying a coating on the surface of a resin molded product molded in the mold cavity in the mold cavity. In the mold for coating molding, on the mold cavity surface on the side where the paint is not injected, a groove is formed in a part where the surface of the resin molded product molded on the opposite mold cavity surface does not affect the quality of the molded product appearance. A movable piece which is formed and slidable in the mold opening and closing direction in the groove in a shape substantially matching the shape of the groove in the mold cavity side is arranged in the groove, and the movable piece is moved in the opening and closing direction. The movable mold is provided with a drive mechanism for moving the movable piece back and forth into the mold cavity, so that the cost-side portion of the resin molded product at the position facing the movable piece is filled with the paint on the side where the paint is injected. Pressing against the cavity surface to prevent the flow of paint By regulating, the position of the paint flow end is controlled.
[0016]
(5) In a mold having a mold cavity formed by a male mold and a female mold, and provided with a paint injection machine for coating the surface of a resin molded product molded in the mold cavity in the mold cavity. In the mold for coating molding, a groove is formed in a portion of the mold cavity on the side where the paint is injected, where the surface portion of the resin molded product facing the surface does not affect the appearance of the molded product. A movable piece slidable in the mold opening and closing direction in the groove in a shape substantially coinciding with the mold cavity side shape is arranged in the groove, and a driving mechanism for moving the movable piece in the opening and closing direction is arranged. Since the movable piece can move forward and backward into the mold cavity, the filling of the paint into the movable piece and the resin molded product located at a position facing the movable piece is delayed to control the position of the paint flow end. Configuration.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a mold for in-mold coating molding according to the present invention will be described with reference to the drawings. 1 to 5 relate to an embodiment of the present invention. FIG. 1 is a structural diagram showing a schematic structure for explaining a configuration of an in-mold coating forming die. FIG. 2 is an in-mold coating forming metal. It is explanatory drawing for demonstrating the shape of the convex part arrange | positioned at the type | mold. FIG. 3 is a conceptual diagram for explaining a resin filling state and a coating state in the vicinity of a convex portion, and FIG. 4 is a diagram for explaining a flowing state of a paint in a mold. FIG. 5 is a conceptual diagram for explaining a convex portion or a movable piece arranged on a mold for in-mold coating forming according to another embodiment. FIG. 6 is a diagram for explaining a paint flowing state in a mold according to a conventional method and a comparative example. FIG. 7 is a flow chart for explaining the steps of the conventional in-mold coating forming method.
[0018]
One preferred example of the mold for in-mold coating molding 100 (sometimes referred to as the mold 100) according to the present invention will be described in detail below with reference to FIGS. The mold 100 according to the present invention includes a movable mold 10, a fixed mold 20, a convex portion 1, and a paint injector 50. In the example of the embodiment shown in FIG. 1, the movable mold 10 is a female mold and the fixed mold 20 is a male mold.
[0019]
The mold 100 has a structure in which a fixed mold 20 which is a male mold and a movable mold 10 which is a female mold are fitted at a fitting portion having a swirling structure, and a mold cavity 15 is formed inside the fitted state in the fitted state. The fitting portion of the swirling structure (sometimes referred to as a swirling portion) is formed over the entire circumference of the mold cavity 15.
The mold 100 can prevent the resin filled in the mold cavity 15 from leaking out of the mold 100 at the feeding portion.
[0020]
Next, details of the arrangement and shape of the protrusions 1 shown in FIG. 1 will be described.
The molded article molded by the mold 100 shown in FIG. 1 is a rectangular flat plate as schematically shown in FIG. 4, and has a paint inlet 51 formed on one side thereof.
[0021]
Normally, when an in-mold coated molded article having such a shape is formed, as shown in FIG. 6A, the flow end of the paint is set at the corner at the end opposite to the side where the paint inlet 51 is disposed. It is formed in the K portion. When a paint containing a glitter material as described above is used, the glitter pigment in the paint is oriented at the corner K at the flow end of the paint, resulting in poor appearance.
[0022]
For this reason, the mold 100 shown in FIG. 1 is a mold cavity surface of the movable mold 10 which is a mold on the paint injection side, and the surface portion of the opposed resin molded product does not affect the quality of the molded product appearance. And the height H of the convex portion 1 is formed to be greater than the thickness of the coating that covers the surface of the molded article in a step described later, and at least a part of the side surface of the convex portion 1 is formed in the mold opening / closing direction. It was formed by tilting.
[0023]
The reason why the inclined surface is formed on the convex portion 1 will be described.
As shown in FIG. 3 (2), a resin is filled in the vicinity of the convex portion 1 on which the inclined surface is formed, and then the mold 100 is slightly opened to allow a space between the resin molded product and the mold cavity surface of the movable mold 10 to move. When a gap (sometimes referred to as a gap) for injecting paint into the mold is formed, the size of the gap differs in a direction perpendicular to the mold opening and closing direction and in a direction other than the direction.
[0024]
In other words, the thickness of the gap shown in FIG. 3 (3) is the largest when the thickness T1 of the gap formed on the surface orthogonal to the mold opening and closing direction is large, and is parallel to the mold opening and closing direction on the side surface of the convex portion 1. The thickness T2 of the gap formed in the appropriate portion is the smallest. The thickness T3 of the gap formed on the inclined surface is a thickness between the thicknesses T1 and T2.
In particular, the thickness T2 of the gap formed in a parallel part in the mold opening and closing direction on the side surface of the convex portion 1 is very small because there is only shrinkage due to cooling of the resin molded product.
[0025]
The paint flows on the surface of the resin molded product in the paint injection and mold clamping steps described later, but as shown in FIG. It does not flow into the convex portion 1 from the direction of T1, but preferentially flows through the portion of T1, which is the largest gap, and enters the gap M of the convex portion 1 shown in FIG. Will flow in. Therefore, the timing at which the paint flows into the gap M formed on the end face side of the projection 1 is delayed.
[0026]
Therefore, a preferable position for forming the convex portion 1 is a position of the mold cavity which does not affect the appearance of the molded product, and a position as close as possible to a portion where the paint flow end is formed when the convex portion 1 is not formed. . Further, it is preferable to form an inclined surface on the side surface of the convex portion 1 closer to the flow end.
According to the convex portion 1 having the above-described configuration, the paint flowing from the paint inlet 51 side reaches the convex portion 1 and then flows so as to bypass the convex portion 1, and the inclined surface formed on the paint flow end side. Flows into the gap M of the projection 1 from the side.
Then, with the above configuration, the timing at which the paint flows into the gap M of the convex portion 1 can be effectively delayed.
[0027]
Although the position of the mold cavity portion that does not affect the appearance differs depending on the molded product, the timing of the paint flowing into the convex portion 1 can be adjusted by adjusting the angle of the inclined surface and the like.
For example, when the inclination angle θ shown in FIG. 2 (3) is reduced to approach the direction parallel to the mold opening / closing direction, the thickness T2 of the gap becomes small, so that the paint does not easily flow into the gap M. The timing at which the paint flows into the gap M of the projection 1 is greatly delayed.
[0028]
When the angle of inclination θ is increased to approach the direction orthogonal to the mold opening and closing direction, the size of the gap thickness T2 increases, so that the paint easily flows into the gap M and the paint flows into the gap M. The effect of delaying the timing is reduced.
By adjusting the arrangement of the protrusions 1 and the angle θ of the inclined surface, the flow end of the paint is adjusted to the space M of the protrusions 1 from the corner K or a mold cavity portion which does not affect the appearance. , It is possible to obtain a good molded product.
[0029]
For comparison, a case where the convex portion 200 having no inclined surface is arranged in FIG. 1 will be described. When the height of the convex portion 200 is smaller than the thickness of the coating, as shown in FIG. The void formed on the end face side of the convex portion 200 passes without bypassing, so that the effect of delaying the timing at which the paint flows into the convex portion 200 can hardly be expected. When the height of the convex portion 200 is larger than the thickness of the coating, the resin cannot flow into the portion facing the convex portion 200, so that the paint only flows around the convex portion 200, so that the end face does not flow. It cannot flow into the side gap.
[0030]
In addition, when a narrow portion is formed in the mold cavity 15 due to the formation of the convex portion 1, the resin flow may greatly change in the resin filling step.
In the embodiment shown in FIG. 1, the concave portion 3 is formed at a position facing the convex portion 1 so that a portion as small as possible in the mold cavity 15 is not formed.
[0031]
Next, the paint injector 50 will be described briefly.
The paint injection machine 50 in the present embodiment is attached to the movable mold 10 and can inject paint into the mold cavity 15 from the paint injection port 51 provided on the mold cavity surface of the movable mold 10. It is configured as follows.
Further, a valve (not shown) is attached to the paint injection port 51 of the paint injection machine 50. At the time of injection molding of the base material, the valve is closed so that the inside of the mold cavity 15 of the mold 100 is closed. Is prevented from entering the paint injection machine 50 through the paint injection port 51.
[0032]
Then, the paint injector 50 in the present embodiment is driven by a driving device (not shown) to accurately supply the paint supplied into the paint injector 50 by a desired amount from the mold cavity surface of the movable mold 10. It is configured so that it can be injected.
[0033]
In addition, the paint injection machine 50 in the present embodiment is configured to inject paint from the mold cavity surface of the movable mold 10 as described above, but is not limited thereto, and is formed in the mold cavity 15. The paint may be injected into the gap formed between the resin molded product and the mold cavity surface, and the paint injector 50 may be mounted on the fixed mold 20 if the conditions are satisfied.
[0034]
Hereinafter, an in-mold coating molding method using the mold 100 will be described.
First, as a first step, the mold 100 is clamped by a mold clamping device (not shown). In this state, the vicinity of the convex portion 1 in the mold cavity 15 is as shown in FIG. Then, as shown in FIG. 3 (2), a thermoplastic resin as a base material is injected into a mold (in the present embodiment, an ABS resin is used as a base material: UT20B manufactured by Ube Sicon Co., Ltd.).
[0035]
Thereafter, the substrate is cooled to a certain degree (to the extent that it can withstand the injection pressure of the paint described later). After the base material is cooled, the mold cavity is set to a state in which the mold is slightly opened as shown in FIG. 3 (3) (in this embodiment, the movable mold 10 is moved by about 1 mm in the mold opening direction). A gap (sometimes referred to as a gap) is generated between the resin molded product molded in 15 and the mold cavity surface of the movable mold 10.
[0036]
As described above, when the mold 100 is slightly opened to form a gap for injecting paint between the resin molded product and the mold cavity surface of the movable mold 10, the size of the gap depends on the mold opening and closing direction. Are different in a direction orthogonal to and in a direction that is not so.
The thickness of the gap illustrated in FIG. 3 (4) is the largest at the gap thickness T1 (1 mm in the present embodiment) on the side orthogonal to the mold opening and closing direction, and the thickness T2 (1 mm in the mold opening and closing direction). In the present embodiment, the resin shrinkage) is the smallest.
In addition, the thickness T3 of the gap on the inclined surface side is a thickness between the thicknesses T1 and T2 (in the present embodiment, the thickness T3 is 0.7 mm with the inclination angle θ being 45 degrees).
[0037]
After the gap is formed, 25 ml (milliliter) of the paint is injected from the paint inlet 51 into the gap by the paint injector 50. In addition, the coating surface area of the molded article molded by the mold used in the present embodiment is 2500 cm. ² And the thickness of the coating film is about 0.1 mm.
The paint used in the present embodiment is Pluglas # 8000: Silver Metallic (manufactured by Dainippon Paint Co., Ltd.).
[0038]
After the paint is injected, the movable mold 10 is moved in the direction of the fixed mold 20, the mold 100 is closed again, and the mold is closed, so that the paint in the gap is spread and spread, and the surface of the molded product is covered with the paint. I do.
[0039]
At that time, as shown in FIG. 4, the paint that has reached the convex portion 1 by traveling through the void in the mold cavity 15 does not flow into the convex portion 1 from the direction of the void T1 and has the largest void T1. By flowing the portion preferentially and flowing into the convex portion from the direction of T3 having a relatively large gap, the timing of the paint flowing into the convex portion 1 is delayed, so that the flow end of the paint is more convex than the corner K. It changes to the position of part 1.
Then, the paint is spread to every corner of the coating region in the mold cavity 15 of the mold 100, and the pressure is kept applied at the same time.
[0040]
The paint that has reached the corner K temporarily stops flowing there, causing uneven alignment. Thereafter, when the paint flows into the convex portion 1, the paint slightly reflows, and the generated uneven alignment occurs. Eliminates and provides a good coated surface.
In the case of molding the resin, since the skin layer resin is cooled and solidified and the flow is stopped, even if the internal resin reflows, the skin layer does not reflow, so that the alignment unevenness is not eliminated, but in the case of paint, Since almost no skin layer is formed at the time of molding, unevenness in orientation is eliminated by reflowing.
In the above steps, by setting the flow end of the coating material to a portion that does not affect the appearance, it was possible to obtain a good in-mold coated molded article without appearance defects.
[0041]
Next, other embodiments will be described only with respect to portions different from the above-described embodiment.
[0042]
In the embodiment shown in FIG. 5 (1), on the mold cavity surface on the side where the paint is injected, the opposite surface portion of the resin molded product does not affect the quality of the appearance of the molded product. A convex portion 1A having a portion and a large portion is formed.
When the convex portion 1A is viewed from the A-A direction, the convex portion 1A has a rectangular frame shape, a portion L1 larger than the thickness of the coating is formed on the direction side of the paint inlet 51, and the convex portion 1A is not formed. A portion L2 smaller than the thickness of the coating is formed on the side where the flow end is formed.
[0043]
When the paint is injected, as shown in FIG. 5A, the paint that has progressed through the gap in the mold cavity 15 and has reached a portion larger than the coating thickness of the convex portion 1A is convex from the L1 side of the convex portion 1A. It does not flow into the frame of the portion 1A, but flows from the L2 side of the convex portion 1A having a relatively large gap. Therefore, the timing at which the paint flows into the frame of the convex portion 1 is delayed, and the position of the flowing end of the paint changes.
When the mold of the embodiment shown in FIG. 5A is used, the paint flows as in the above-described embodiment, and once the paint reaches the corner K, the flow stops there and the alignment unevenness occurs. Thereafter, when the paint flows into the gap, the paint slightly reflows, so that the generated alignment unevenness is eliminated and a good coated surface is obtained.
[0044]
Next, details of the mold for in-mold coating forming provided with a movable piece of the hydraulic cylinder drive type will be described with reference to FIG.
In the embodiment used in FIG. 5 (2), a groove is formed in a portion of the mold cavity on the side of one of the male mold and the female mold on which paint is not injected and which does not affect the appearance of the molded product. A movable piece 1B having a shape substantially matching the shape of the groove portion on the side of the mold cavity and slidable in the mold opening and closing direction in the groove portion is disposed in the groove portion.
Further, a driving mechanism for moving the movable piece 1B in the mold opening / closing direction is provided so that the movable piece 1B can move forward and backward into the mold cavity, so that a resin molded product at a position facing the movable piece 1B can be held down. By pressing the paint on the mold cavity surface on the side where the paint is injected, the flow of the paint is regulated and the flow state of the paint is controlled.
[0045]
The behavior of the movable piece 1B and the flow state of the paint will be described.
First, as a first step, the mold 100 is clamped by a mold clamping device (not shown). In this state, the movable piece 1B is controlled by the hydraulic cylinder by the pressing mechanism, so that the cavity-side end face of the movable piece 1B and the mold cavity surface are arranged on the same plane.
[0046]
Then, a thermoplastic resin as a base material is injected into a mold (an ABS resin as a base material: UT20B manufactured by Ube Sicon Co., Ltd., as in the above embodiment). Thereafter, the substrate is cooled to some extent.
After cooling the base material, the mold is slightly opened, and a gap is formed between the resin molded product molded in the mold cavity 15 and the mold cavity surface of the movable mold 10.
[0047]
After the gap is created, the hydraulic cylinder is operated to move the movable piece 1B to the cavity side so that one end of the movable piece 1B is brought into contact with the resin molded product. The paint shown in Table 1 is injected while being pressed strongly against the mold cavity surface. The portion where the resin molded product is pressed against the mold cavity surface serves as a weir through which the paint cannot flow. Therefore, the paint flows around the portion where the resin molded product is pressed.
[0048]
Then, after the paint is injected, the movable mold 10 is moved in the direction of the fixed mold 20, the mold 100 is closed again, and the mold is closed. At the same time, the pressure is applied while spreading to every corner of the coating area in the mold cavity 15. The hydraulic pressure of the movable piece 1B pressed by the hydraulic cylinder is adjusted so that the movable piece 1B gradually moves to the opposite side of the cavity while being in contact with the molded product as the mold is closed. Then, when the paint has spread to all corners except the pressed portion, the hydraulic cylinder is driven to move the movable piece 1B to the opposite side of the cavity, and the cavity side end surface of the movable piece 1B and the mold cavity surface are moved. Are arranged on the same plane.
[0049]
When the cavity-side end surface of the movable piece 1A and the mold cavity surface are arranged on the same plane, a portion where the resin molded product is pressed against the mold cavity surface is separated, so that a gap is formed. The paint flows and flows into the portion, and a paint flow end is formed in the gap.
The paint that has reached the corner K temporarily stops flowing there, causing orientation unevenness. Thereafter, when the paint flows into the gap, the paint slightly reflows, thereby eliminating the generated alignment unevenness. Good coating surface.
[0050]
The pressing mechanism that can be used in the present invention is not limited to the hydraulic cylinder described above, but may be a pneumatic cylinder. Further, a system in which the movable piece 1B is pulled to the movable mold 10 using an electromagnet may be used.
Further, in the case of the mold for in-mold coating forming of the embodiment shown in FIG. 5B, the timing of the paint flowing into the gap can be controlled by the operation timing of the drive mechanism. Accordingly, this is a very preferable mode in that the effect of delaying the paint injection timing can be freely controlled, and has an excellent effect that the range of applicable molded articles is wide.
[0051]
Next, in the embodiment used in FIG. 5 (3), the appearance of a molded product is affected by the mold cavity surface on the mold cavity surface on the side where paint is injected on either the male mold or the female mold. A groove is formed in a portion where there is no groove, and a movable piece 1C that is slidable in the mold opening / closing direction in the groove in a shape substantially matching the shape of the groove on the mold cavity side is disposed in the groove.
In addition, a drive mechanism for moving the movable piece 1C in the opening / closing direction is provided so that the movable piece 1C can move forward and backward into the mold cavity. The flow state of the paint is controlled by regulating the flow of the paint by pressing against the mold cavity surface on the side where the paint is injected.
[0052]
The behavior of the movable piece 1C and the flow state of the paint will be described.
First, as a first step, the mold 100 is clamped by a mold clamping device (not shown). In this state, the movable piece 1B is controlled by the hydraulic cylinder so that the cavity-side end surface of the movable piece 1A and the mold cavity surface are arranged on the same plane.
[0053]
Then, the thermoplastic resin as the base material is injected into the mold. Thereafter, the substrate is cooled to some extent.
After cooling the base material, the mold is slightly opened, and a gap is formed between the resin molded product molded in the mold cavity 15 and the mold cavity surface of the movable mold 10.
[0054]
After the gap is formed, the hydraulic cylinder is operated to move the movable piece 1C to the cavity side so that one end of the movable piece 1C is brought into contact with the resin molded product, and the paint shown in Table 1 is injected. .
[0055]
The portion where the movable piece 1C is pressed against the resin molded product serves as a weir through which the paint cannot flow. Therefore, the paint flows around the portion where the movable piece 1C is pressed. After the paint is injected, the movable mold 10 is moved in the direction of the fixed mold 20, and the mold 100 is closed again to close the mold. At the same time, the pressure is applied while spreading to every corner of the coating area in the cavity 15.
[0056]
The hydraulic pressure of the movable piece 1C pressed by the hydraulic cylinder is adjusted so that the movable piece 1C gradually moves to the opposite side of the cavity as the mold is clamped while being kept in contact with the molded product. Then, when the paint has spread to all corners except the pressed portion, the hydraulic cylinder is driven to move the movable piece 1C to the opposite side of the cavity, and the cavity side end surface of the movable piece 1C and the mold cavity surface are moved. Are arranged on the same plane.
[0057]
When the cavity-side end face of the movable piece 1C and the mold cavity face are arranged in the same plane, a portion where the movable piece 1C is pressed against the resin molded product is separated to form a gap. The paint flows into the gap and forms a paint flow end in the gap.
The paint that has reached the corner K temporarily stops flowing there, causing orientation unevenness. Thereafter, when the paint flows into the gap, the paint slightly reflows, thereby eliminating the generated alignment unevenness. Good coating surface.
[0058]
In the case of the mold for in-mold coating molding of the embodiment shown in FIG. 5 (4), the timing of the paint flowing into the gap is determined by the operation timing of the drive mechanism, similarly to the embodiment shown in FIG. 5 (3). , Can control. Accordingly, this is a very preferable mode in that the effect of delaying the paint injection timing can be freely controlled, and has an excellent effect that the range of applicable molded articles is wide.
[0059]
【The invention's effect】
In the present invention, an excellent effect of obtaining a good molded article can be obtained by controlling the flow end of the paint so as not to affect the appearance of the molded article.
[0060]
In the first and third aspects of the present invention, on the mold cavity surface on the side where the paint is injected, a convex portion is disposed on a portion where the surface portion of the opposite resin molded product does not affect the appearance of the molded product. Due to the shape effect of the projection, the timing at which the paint flows into the end face of the projection is delayed, and the flow end of the paint is controlled so as to be a portion that does not affect the appearance of the molded product. To get the excellent effect.
[0061]
Further, in the second aspect, by forming the concave portion at a position facing the convex portion, it is possible to prevent a resin flow failure that may occur due to the convex portion.
[0062]
In the fourth and fifth inventions, the gap where the paint flows is locally regulated using the movable piece that moves forward and backward with respect to the mold cavity by the driving device, and the flowing end of the paint affects the appearance of the molded article. By controlling so as to be a portion not giving the excellent effect, an excellent effect of obtaining a good molded product is obtained.
[Brief description of the drawings]
FIG. 1 is a structural diagram showing a schematic structure for explaining a configuration of an in-mold coating forming die according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram for explaining a shape of a convex portion provided on a mold for in-mold coating forming according to an embodiment of the present invention.
FIG. 3 is a conceptual diagram for explaining a resin filling state and a coating state in the vicinity of a convex portion of an in-mold coating molding die according to an embodiment of the present invention.
FIG. 4 is a diagram for explaining a paint flowing state of an in-mold coating molding die according to the embodiment of the present invention.
FIG. 5 is a conceptual diagram for explaining a convex portion or a movable piece arranged on a mold for in-mold coating molding according to another embodiment of the present invention.
FIG. 6 is a diagram for explaining a paint flowing state of a mold according to a conventional method and a comparative example.
FIG. 7 is a flowchart illustrating steps of a conventional method for forming and coating an in-mold.
[Explanation of symbols]
1 convex part
1A convex part
1B Movable piece
1C movable piece
3 recess
5 groove
7 Hydraulic cylinder (pressing mechanism)
15 Mold cavity
10 movable type
20 fixed type
50 Paint injection machine
51 Paint inlet
100 Mold for in-mold coating molding
K corner

Claims

For molding in-mold coating, having a mold cavity formed by a male mold and a female mold, and having a paint injection machine for applying a coating in the mold cavity to a surface of a resin molded product molded in the mold cavity. In the mold,
On the mold cavity surface on the side where the paint is injected, a convex portion is disposed at a portion where the surface portion of the resin molded product facing the same does not affect the quality of the molded product appearance, and the height of the convex portion is set to the height of the coating. By being formed larger than the thickness, at least a part of the side surface of the convex portion is formed to be inclined with respect to the mold opening / closing direction, thereby delaying the filling of the paint on the surface portion of the fat molded article facing the convex portion. Coating mold for controlling the position of the paint flow end.

The mold for in-mold coating molding according to claim 1, wherein a concave portion through which at least a part of the convex portion can be inserted and removed is formed in a mold cavity surface facing the convex portion.

For molding in-mold coating, having a mold cavity formed by a male mold and a female mold, and having a paint injection machine for applying a coating in the mold cavity to a surface of a resin molded product molded in the mold cavity. In the mold,
On the mold cavity surface on the side where the paint is injected, a convex portion is arranged at a portion where the surface portion of the opposite resin molded product does not affect the appearance of the molded product, and the height of the convex portion in the mold opening / closing direction. Is formed to form a portion smaller than the thickness of the coating and a portion larger than the thickness of the coating, thereby delaying the filling of the surface of the fat molded article facing the convex portion with the paint, and thereby determining the position of the paint flow end. To control the in-mold coating molding die.

For molding in-mold coating, having a mold cavity formed by a male mold and a female mold, and having a paint injection machine for applying a coating in the mold cavity to a surface of a resin molded product molded in the mold cavity. In the mold,
On the mold cavity surface on the side where the paint is not injected, a groove portion is formed in a portion where the surface portion of the resin molded product molded by the opposing mold cavity surface does not affect the quality of the molded product appearance. A movable piece slidable in the mold opening and closing direction in the groove in a shape substantially coinciding with the mold cavity side shape is arranged in the groove, and a drive mechanism for moving the movable piece in the opening and closing direction is provided. The movable piece can be moved forward and backward into the mold cavity, so that the cost-side portion of the resin molded product located at the position facing the movable piece is pressed against the mold cavity surface on the side where the paint is injected, thereby forming the paint. An in-mold coating molding die that controls the position of the paint flow end by regulating the flow.

For molding in-mold coating, having a mold cavity formed by a male mold and a female mold, and having a paint injection machine for applying a coating in the mold cavity to a surface of a resin molded product molded in the mold cavity. In the mold,
On the mold cavity surface on the side where the paint is injected, a groove is formed in a portion where the surface portion of the opposed resin molded product does not affect the appearance of the molded product, and substantially matches the shape of the groove on the mold cavity side. A movable piece which is slidable in the mold opening and closing direction in the groove in the groove is provided in the groove, and a drive mechanism for moving the movable piece in the opening and closing direction is provided. In-mold coating molding die for controlling the position of the paint flow end by delaying the filling of paint into the movable piece and the resin molded product located at a position facing the movable piece by being configured to be able to move forward and backward in the mold. .