JP3578571B2 - Manufacturing method of automobile exterior parts and manufacturing method of automobile pillar - Google Patents

Description

【００６４】
実施例１の金型組立体におけるキャビティ４０の大きさを４７０．００ｍｍ×４５０．００ｍｍ×３．００ｍｍとし、形状は直方体とした。固定金型部１０を炭素鋼Ｓ５５Ｃから作製した。入れ子３０を装着する固定金型部１０の部分を、炭素鋼Ｓ５５Ｃから成る中子１２から構成し、中子１２に入れ子装着部１１を設けた。入れ子装着部１１の内寸法が４７１．２０ｍｍ×４５１．２０ｍｍ、深さが４．０２ｍｍとなるように中子１２の切削加工を行った。
【００６５】
２液硬化型エポキシ系接着剤（図示せず）を用いて、入れ子３０を中子１２の入れ子装着部１１内に固定した（図１の（Ｂ）参照）。その後、入れ子３０のキャビティ面３１に対して、ダイヤモンド砥石及び酸化セリウム砥石を用いた研磨及び仕上げを行ない、入れ子３０のキャビティ面３１の表面粗さＲ_ｍａｘを０．０２μｍとした。隙間ゲージを用いて入れ子３０と入れ子装着部１１との間のクリアランス（Ｄ）を測定したところ、最低クリアランスは０．０５ｍｍであった。次いで、中子１２を固定金型部１０に装着した。
【００６６】
炭素鋼Ｓ５５Ｃから抑えプレート３２を作製した。抑えプレート３２の内法寸法を４７０．００ｍｍ×４５０．００ｍｍとした。この抑えプレート３２を固定金型部１０にビス（図示せず）を用いて固定した（図１の（Ｃ）参照）。入れ子３０と抑えプレート３２との間のクリアランス（Ｃ）は、平均で０．０１９ｍｍであった。また、入れ子３０に対する抑えプレート３２の抑え代（ΔＳ）は、０．５ｍｍであった。尚、図１の（Ｃ）にはゲート部の図示を省略した。
【００６７】
一方、可動金型部２０を炭素鋼Ｓ５５Ｃから作製した。そして、可動金型部２０と図１の（Ｃ）に示した固定金型部１０を組み付けて金型組立体を完成させた（図１の（Ａ）参照）。
【００６８】
完成した金型組立体を成形装置に取り付けた後、金型組立体を金型温調機を用いて１３０゜Ｃまで加熱後、４０゜Ｃまで急冷しても、結晶化ガラスから作製された入れ子３０に割れ等の損傷は発生しなかった。
【００６９】
射出成形装置として三菱重工業株式会社製、５５０ＭＭ射出成形装置を用い、金型組立体を８０゜Ｃに加熱した。そして、以下の表９に示すホウ酸アルミニウムウィスカー繊維から成る無機繊維を２０重量％含有するポリカーボネート樹脂から成る熱可塑性樹脂を用い、以下の表９に示す射出成形条件にて、キャビティ４０内を完全に充填するのに十分な量の溶融樹脂をゲート部１３を介してキャビティ４０内に射出した。そして、射出完了から２０秒経過後、自動車用部材を金型組立体から取り出した。
【００７０】
【表９】
ホウ酸アルミニウムウィスカー繊維
平均長さ：１０μｍ
平均直径：０．１μｍ
成形条件
金型温度： ８０゜Ｃ
樹脂温度：３１０゜Ｃ
射出圧力：５００ｋｇｆ／ｃｍ^２−Ｇ
【００７１】
自動車用部材の表面（入れ子１３と接していた面）は、金型温度が低いにも拘らず、その端部に至るまで鏡面性を有していた。表面写像性測定機を用いて自動車用部材の表面の平滑性を測定した結果、完全鏡面１００％に対して、９５％と非常に高い鏡面性を有していた。また、自動車用部材の物性測定を行ったところ、曲げ弾性率６．０ＧＰａ、線膨張係数２．５×１０^−５／ｄｅｇ、荷重撓み温度１４５゜Ｃであり、所望の性能を有していることが分かった。更に、連続して成形を１００００サイクル行ったが、入れ子３０に割れ等の損傷は発生しなかった。
【００７２】
成形した自動車用部材の表面を、ウレタン系塗料をスプレー法により塗装した後、１４０゜Ｃのオーブン中で２時間かけて塗料を硬化させた。その結果、被写体が鮮明に映し出され、写像性に優れた自動車用外装部品が得られた。また、自動車用部材の成形サイクルは約４０秒／個であり、量産性としても優れていた。
【００７３】
（比較例１Ａ）
比較例１Ａにおいては、金型をスタバックス鋼から作製し、金型のキャビティ面を鏡面研磨した金型組立体を用いた。尚、比較例１Ａの金型組立体の構造は、図３の（Ａ）に模式的な一部端面図を示すように、入れ子及び抑えプレートを備えていないことを除き、実施例１の金型組立体と同様の構造を有する。そして、実施例１と同様の熱可塑性樹脂を使用して、実施例１と同様の成形条件にて成形を行った。その結果、キャビティ内での溶融樹脂の流動性が悪く、キャビティ内を完全に溶融樹脂で充填することができなかった。そこで、射出圧力を２００ｋｇｆ／ｃｍ^２−Ｇ増加させ、７００ｋｇｆ／ｃｍ^２−Ｇとして成形を行った。得られた自動車用部材の表面には、無機繊維が析出しており、外観が非常に劣っていた。表面写像性測定機にて自動車用部材の表面平滑性を測定したところ、完全鏡面１００％に対し、７％であり、実施例１の自動車用部材と比較すると鏡面性が著しく低かった。
【００７４】
（比較例１Ｂ）
比較例１Ｂにおいては、図３の（Ｂ）に模式的な一部端面図を示すように、抑えプレートを用いていない構造の金型組立体を使用した。そして、実施例１と同様の熱可塑性樹脂を使用して、実施例１と同様の成形条件にて成形を行った。その結果、自動車用部材端部の外観が劣っており、バリ等の外観不良が発生していた。また、成形１５サイクルで入れ子３０の端部に割れが生じた。
【００７５】
（比較例１Ｃ）
比較例１Ｃでは、実施例１で用いた金型組立体において、抑えプレート３２と入れ子３０との間のクリアランス（Ｃ）を０．０４ｍｍとした。そして、実施例１と同様の熱可塑性樹脂を使用して、実施例１と同様の成形条件にて成形を行った。その結果、抑えプレート３２と入れ子３０との間の隙間に溶融樹脂が侵入し、離型時に自動車用部材を金型組立体から取り外すことができなかった。
【００７６】
（比較例１Ｄ）
比較例１Ｄでは、実施例１で用いた金型組立体において、入れ子３０に対する抑えプレート３２の抑え代（ΔＳ）を０．０５ｍｍとした。そして、実施例１と同様の熱可塑性樹脂を使用して、実施例１と同様の成形条件にて成形を行った。その結果、入れ子外周部からクラックが成長し、成形５サイクル目には入れ子３０の全面に割れが発生した。
【００７７】
（実施例２）
実施例２においても、実施例１と同様の金型組立体を用いた。また、熱可塑性樹脂として、無機繊維としてシランカップリング処理したガラス繊維を５０重量％含有したポリカーボネート樹脂を用いた。尚、ガラス繊維の平均長さは７０μｍ、平均直径は１０μｍであった。成形条件としては、樹脂温度を３３０゜Ｃと高くした以外は、実施例１と同様とした。実施例１と同様の塗装を行う前の自動車用部材の表面写像性測定機による表面平滑性の測定結果及び物性測定結果を表１０に示す。尚、成形した自動車用部材の表面を、ウレタン系塗料をスプレー法により塗装した後、１４０゜Ｃのオーブン中で２時間かけて塗料を硬化させた。その結果、被写体が鮮明に映し出され、写像性に優れた自動車用外装部品が得られた。
【００７８】
（比較例２Ａ〜比較例２Ｃ）
比較例２Ａ〜比較例２Ｃにおいては、実施例１と同様の金型組立体を用いた。熱可塑性樹脂として、無機繊維としてシランカップリング処理したガラス繊維を含有したポリカーボネート樹脂を用いた。使用した熱可塑性樹脂の諸元を表１０に示す。実施例２と同様の成形条件にて得られた自動車用部材の表面平滑性の測定結果及び物性測定結果を表１０に示す。尚、表１０中、繊維長さ及び繊維直径は繊維の平均長さ及び平均直径を意味する。線膨張係数の単位は、１０^−５／ｄｅｇである。
【００７９】
【表１０】

【００８０】
比較例２Ｂ及び比較例２Ｃから明らかなように、無機繊維の平均長さが４００μｍを超えると、写像性が低下する。また、比較例２Ａから明らかなように、無機繊維の含有率が１５重量％未満では、自動車用部材に要求される線膨張係数（３．０×１０^−５／ｄｅｇ以下）及び曲げ弾性率を満足しない。
【００８１】
（実施例３）
以下に説明する実施例３及び実施例４は、自動車用部材の成形方法、並びに自動車用ピラーの製造方法に関する。実施例３にて用いた金型組立体の模式的な一部端面図を図２の（Ａ）、（Ｂ）及び（Ｃ）に示す。実施例３においては、図２の（Ｂ）に示すように入れ子１３０の製作及び装着を行った。厚さ４．５ｍｍ、長さ２７５．０ｍｍ、幅８５．０ｍｍの平板状の結晶化ガラス（結晶化度７０％）から入れ子１３０を作製した。尚、この結晶化ガラスの特性は実施例１にて使用した結晶化ガラスと同様である。そして、８００゜Ｃの高温炉の中で曲率半径５００ｍｍのセラミック製の型の上にこの平板状の結晶化ガラスを載置して自然賦形させた後、研削加工した。その後、入れ子１３０のキャビティ面１３１に対して、ダイヤモンド砥石及び酸化セリウム砥石を用いた研磨及び仕上げを行い、入れ子のキャビティ面１３１の表面粗さＲ_ｍａｘを０．０２μｍとした。入れ子１３０の最終的な大きさを、厚さ４．００ｍｍ、長さ２７１．００ｍｍ、幅８１．００ｍｍとした。また、入れ子１３０のキャビティ面１３１の曲率半径は５００ｍｍである。
【００８２】
固定金型部１１０に設けられた入れ子装着部１１１の内法寸法を２７１．２０ｍｍ×８１．２０ｍｍとした。尚、入れ子装着部１１１は、入れ子１３０のキャビティ面１３１と反対側の面と同形状を有する。次いで、入れ子１３０を入れ子装着部１１１内にエポキシ系接着剤（図示せず）で固定した（図２の（Ｂ）参照）。隙間ゲージを用いて入れ子１３０と入れ子装着部１１１の間のクリアランス（Ｄ）を測定したところ、最低クリアランスは、０．０５ｍｍであった。
【００８３】
次に、図２の（Ｃ）に示すように抑えプレート１３２の製作を行った。抑えプレート１３２を炭素鋼Ｓ５５Ｃから作製した。抑えプレート１３２の内法寸法を２７０．００ｍｍ×８０．００ｍｍとした。入れ子１３０のキャビティ面１３１と対向する抑えプレート１３２の面の曲率半径を５００ｍｍとした。次いで、抑えプレート１３２を固定金型部１１０にビス（図示せず）を用いて固定した。入れ子１３０と抑えプレート１３２との間のクリアランス（Ｃ）は、平均で０．０１９ｍｍであった。入れ子１３０に対する抑えプレート１３２の抑え代（ΔＳ）は、０．５ｍｍであった。
【００８４】
次に、図２の（Ａ）に示すように可動金型部１２０と固定金型部１１０との組み付けを行ない、金型組立体を完成させた。尚、自動車用ピラーの寸法は、長さ２７０ｍｍ、幅８０ｍｍ、厚さ２ｍｍ、面の曲率半径は５００ｍｍである。完成した金型組立体を射出成形装置に取り付けた。そして、金型温調機を用いて１３０゜Ｃまで加熱した後、４０゜Ｃまで急冷しても、結晶化ガラスから作製された入れ子１３０に割れ等の問題は発生しなかった。
【００８５】
射出成形装置として三菱重工業株式会社製、１５０ＭＳＴ射出成形装置を用い、金型組立体を８０゜Ｃに加熱した。そして、以下の表１１に示すホウ酸アルミニウムウィスカー繊維から成る無機繊維を２０重量％含有するポリカーボネート樹脂から成る熱可塑性樹脂を用い、以下の表１１に示す射出成形条件にて、キャビティ１４０内を完全に充填するのに十分な量の溶融樹脂をゲート部１１３を介してキャビティ１４０内に射出した。そして、射出完了から２０秒経過後、自動車用部材（ピラー部材）を金型組立体から取り出した。
【００８６】
【表１１】
ホウ酸アルミニウムウィスカー繊維
平均長さ：１０μｍ
平均直径：０．１μｍ
成形条件
金型温度： ８０゜Ｃ
樹脂温度：３１０゜Ｃ
射出圧力：５００ｋｇｆ／ｃｍ^２−Ｇ
【００８７】
自動車用部材の表面（入れ子１３０と接していた面）は、金型温度が低いにも拘らず、自動車用部材の端部に至るまで鏡面性を有していた。表面写像性測定機を用いて自動車用部材の表面の平滑性を測定した結果、完全鏡面１００％に対して、９５％と非常に高い鏡面性を有していた。また、自動車用部材の物性測定を行ったところ、曲げ弾性率６．０ＧＰａ、線膨張係数２．５×１０^−５／ｄｅｇ、荷重撓み温度１４５゜Ｃであり、所望の性能を有していることが分かった。更に連続して成形を１００００サイクル行ったが、入れ子１３０に割れ等の損傷は発生しなかった。
【００８８】
成形した自動車用部材（ピラー部材）にアクリル系のハードコート溶液をディップ法にて塗布した後、紫外線照射機にてハードコート溶液を完全に硬化させて自動車用ピラーを完成させた。完成した自動車用ピラーは、非常に綺麗な外観を有しており、無機繊維を含有していない熱可塑性樹脂から成形した自動車用ピラーとほぼ同等の外観を有しており、しかも、自動車用ピラーにクラックは発生していなかった。
【００８９】
（比較例３Ａ）
比較例３Ａにおいては、金型をスタバックス鋼から作製し、金型のキャビティ面を鏡面研磨した金型組立体を用いた。尚、比較例３Ａの金型組立体の構造は、入れ子及び抑えプレートを備えていないことを除き、実施例３の金型組立体と同様の構造を有する。そして、実施例３と同様の熱可塑性樹脂を使用して、実施例３と同様の成形条件にて成形を行った。その結果、キャビティ内での溶融樹脂の流動性が悪く、キャビティ内を完全に溶融樹脂で充填することができなかった。そこで、射出圧力を２００ｋｇｆ／ｃｍ^２−Ｇ増加させ、７００ｋｇｆ／ｃｍ^２−Ｇとして成形を行った。得られた自動車用部材（ピラー部材）の表面には、無機繊維が析出しており、外観が非常に劣っていた。表面写像性測定機にて自動車用部材の表面平滑性を測定したところ、完全鏡面１００％に対し、７％であり、実施例３の自動車用部材と比較すると鏡面性が著しく低かった。この自動車用部材に実施例３と同様にハードコート処理を行った結果、得られた自動車用部材の表面の外観は劣っており、また、自動車用部材の端部からクラックが発生していた。
【００９０】
（比較例３Ｂ）
比較例３Ｂにおいては、入れ子１３０を抑えプレートで抑えていない構造の金型組立体を使用した。そして、実施例３と同様の熱可塑性樹脂を使用して、実施例３と同様の成形条件にて成形を行った。その結果、自動車用部材端部の外観が劣っており、バリ等の外観不良が発生していた。また、成形１５サイクルで入れ子１３０の端部に割れが生じた。
【００９１】
（比較例３Ｃ）
比較例３Ｃでは、実施例３で用いた金型組立体において、抑えプレート１３２と入れ子１３０との間のクリアランス（Ｃ）を０．０４ｍｍとした。そして、実施例３と同様の熱可塑性樹脂を使用して、実施例３と同様の成形条件にて成形を行った。その結果、抑えプレート１３２と入れ子１３０との間の隙間に溶融樹脂が侵入し、離型時に自動車用部材を金型組立体から取り外すことができなかった。
【００９２】
（比較例３Ｄ）
比較例３Ｄでは、実施例３で用いた金型組立体において、入れ子１３０に対する抑えプレート１３２の抑え代（ΔＳ）を０．０５ｍｍとした。そして、実施例３と同様の熱可塑性樹脂を使用して、実施例３と同様の成形条件にて成形を行った。その結果、入れ子外周部からクラックが成長し、成形５サイクル目には入れ子の全面に割れが発生した。
【００９３】
（実施例４）
実施例４においては、実施例３と同様の金型組立体を用い、ポリカーボネート樹脂に無機繊維としてシランカップリング処理したガラス繊維を５０重量％添加して成る熱可塑性樹脂を用いて成形を行った。無機繊維の平均長さは７０μｍ、平均直径は１０μｍであった。成形条件としては、樹脂温度を３３０゜Ｃと高くした以外は実施例３と同様の条件にて成形を行った。成形した自動車用部材（ピラー部材）にアクリル系のハードコート溶液をディップ法にて塗布した後、紫外線照射機にてハードコート溶液を完全に硬化させて自動車用ピラーを完成させた。完成した自動車用ピラーは、非常に綺麗な外観を有しており、無機繊維を含有していない熱可塑性樹脂から成形した自動車用ピラーとほぼ同等の外観を有しており、しかも、自動車用ピラーにクラックは発生していなかった。実施例４にて得られた自動車用部材（ピラー部材）の表面平滑性を表面写像性測定機で測定した結果及び物性測定結果を表１２に示す。尚、表１２中、繊維長さ及び繊維直径は繊維の平均長さ及び平均直径を意味する。線膨張係数の単位は、１０^−５／ｄｅｇである。
【００９４】
（比較例４Ａ〜比較例４Ｃ）
比較例４Ａ〜比較例４Ｃにおいては、実施例３と同様の金型組立体を用い、ポリカーボネート樹脂に無機繊維としてシランカップリング処理したガラス繊維を添加して成る熱可塑性樹脂を用いて成形を行った。繊維の平均長さ及び平均直径を表１２に示す。成形条件は実施例４と同様とした。表面写像性測定機で自動車用部材（ピラー部材）表面の平滑性を測定した結果及び物性測定結果を表１２に示す。実施例４と同じ金型組立体を用いて成形を行ったにも拘わらず、比較例４Ｂ及び比較例４Ｃにおいては、無機繊維の平均長さが長すぎ、写像性が不十分であった。また、比較例４Ａにおいては、無機繊維の含有率が１５重量％未満であり、ピラー部材から成る自動車用部材に要求される線膨張係数（３．０×１０^−５／ｄｅｇ以下）及び曲げ弾性率を満足しなかった。
【００９５】
【表１２】

【００９６】
以上、本発明を好ましい実施例に基づき説明したが、本発明はこれらの実施例に限定されるものではない。実施例にて説明した条件や使用した材料は例示であり、また、金型組立体の構造も例示であり、適宜変更することができる。入れ子や抑えプレートの形状や大きさも例示であり、成形すべき自動車用部材の形状等に依存して、適宜設計変更することができる。入れ子は、鏡面性が要求される自動車用部材の表面の部分に対向して金型内に配設すればよく、必要に応じて、可動金型部に設けてもよいし、固定金型部と可動金型部の両方に設けてもよい。
【００９７】
【発明の効果】
本発明の自動車用部材の成形方法によれば、入れ子及び抑えプレートを備えた金型組立体を使用することによって、高弾性率、低線膨張率、高耐熱性熱を有ししかも、極めて優れた鏡面性を有する自動車用部材の成形が可能である。
【００９８】
更には、本発明の自動車用部材の成形方法においては、入れ子を、所定のクリアランス（Ｃ）及び抑え代（ΔＳ）の範囲内で抑えプレートによって抑えることにより、長期的な成形を実施しても、入れ子に破損が生じることがなく、容易且つ安価に鏡面を有する自動車用部材を製作できる。また、自動車用部材の端部の外観を損なうことがなくなり、自動車用部材の端部のバリ発生を防止でき、自動車用部材の不良率低減及び均質化、高品質化を達成することができ、自動車用部材の製造コストの削減を図ることができる。
【００９９】
また、溶融樹脂の流動性が向上するが故に、溶融樹脂の射出圧力を低く設定できるので、自動車用部材に残留する応力を緩和でき、自動車用部材の品質が向上する。更には、溶融樹脂の射出圧力を低減できるので、金型の薄肉化、成形装置の小型化が可能となり、自動車用部材のコストダウンも可能になる。尚、結晶化ガラスから入れ子を作製することで、鏡面性、転写性に優れた自動車用部材を容易に得られる。尚、入れ子を結晶化ガラスから作製すれば、線膨張係数が低く、熱衝撃に対しても強く、破損やクラックが発生し難い入れ子を作製することができる。
【０１００】
本発明の自動車用外装部品の製造方法によれば、繊維強化熱可塑性樹脂を成形して得られる自動車用部材の表面に塗装を施すことにより、高剛性、低線膨張率、高耐熱性であり、外観にも優れる自動車用外装部品が得られる。しかも、外観に優れ軽量化された自動車用外装部品の製造における、量産性の向上、デザインの自由度向上が計れる。
【０１０１】
また、本発明の自動車用ピラーの製造方法によれば、繊維強化熱可塑性樹脂を成形して得られる自動車用部材の表面にハードコート処理をすることにより、高剛性、低線膨張率、高耐熱性であり、外観にも優れる自動車用ピラーが得られる。しかも、ハードコート溶液による自動車用部材のクラック発生を抑制することができる。
【図面の簡単な説明】
【図１】実施例１の実施に適した金型組立体の好ましい態様の模式的な一部端面図、及び金型組立体の組み立て中の模式的な一部端面図である。
【図２】実施例２の実施に適した金型組立体の好ましい態様の模式的な一部端面図、及び金型組立体の組み立て中の模式的な一部端面図である。
【図３】比較例における金型組立体の模式的な一部端面図である。
【符号の説明】
１０，１１０ 固定金型部
１１．１１１ 入れ子装着部
１２ 中子
１３，１１３ ゲート部
２０，１２０ 可動金型部
３０，１３０ 入れ子
３１，１３１ 入れ子のキャビティ面
３２，１３２ 抑えプレート
４０，１４０ キャビティ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for molding an automobile member made of a fiber-reinforced thermoplastic resin, and a method for producing an exterior component for an automobile and a pillar for an automobile.
[0002]
[Prior art]
A mold for molding a molded article based on a thermoplastic resin (hereinafter, simply referred to as a mold) usually includes a thermoplastic resin (hereinafter, simply referred to as a molten resin) melted in a cavity which is a hollow portion provided in the mold. (Which may be referred to as a resin), which is not deformed even by a high pressure at the time of filling, for example, carbon steel, stainless steel, aluminum alloy, and copper alloy. Then, by filling the cavity provided in the mold with the molten resin, a surface having a desired shape and constituting the cavity of the mold (hereinafter referred to as a cavity surface of the mold for convenience) is transferred. Obtained molded products.
[0003]
Automotive exterior parts are required to have high resistance to destruction in the event of a collision, high resistance to deformation due to temperature changes, and excellent appearance characteristics. For this reason, high elastic modulus, low linear expansion, high heat resistance, and high image clarity are also required for the materials constituting the exterior parts for automobiles. The required values for exterior parts for automobiles include, for example, a flexural modulus (ASTM D790) of 4.0 GPa or more and a linear expansion coefficient (ASTM D696) of 3.0 × 10 ^-5 / Deg or less, load deflection temperature (ASTM D648, load 455 kPa) of 140 ° C. or more, and image clarity (specularity) of 85% or more. Conventionally, metal materials have been used as materials for producing automotive exterior parts satisfying these conditions. In general, an automobile exterior component is manufactured by applying a coating after pressing a metal material into a desired shape. Automotive exterior parts made of metal materials satisfy the required performances, but have the disadvantage of being heavy. In the following description, the measurement of the flexural modulus, the coefficient of linear expansion, and the deflection temperature under load are based on ASTM D790, ASTM D696, and ASTM D648 under a load of 455 kPa.
[0004]
Further, since automotive exterior parts made of a metal material are usually manufactured by a press molding method, there is a problem that the degree of freedom in design is low. Therefore, in order to reduce the fuel consumption, reduce the weight, and diversify the design of automobiles, production of automobile exterior parts from a thermoplastic resin has been studied. Usually, after molding a thermoplastic resin to obtain an automobile member, the surface of the automobile member is subjected to a coating treatment to produce an automobile exterior component.
[0005]
Automotive pillars such as front pillars, center pillars, and rear pillars are exterior members that constitute a part of the side body, and are required to have excellent appearance characteristics. Therefore, generally, a pillar for automobiles is formed using a thermoplastic resin containing no filler as a raw material resin. In addition, pillars for automobiles are required to have high strength (particularly, flexural modulus). For this reason, a special shape is usually designed, or the thickness of the automobile pillar is increased to cope with the problem. Further, heat resistance is also required for pillars for automobiles, and engineering plastics are usually used as a raw material resin. Then, after obtaining a vehicle member for manufacturing a vehicle pillar by molding a thermoplastic resin, the surface of the vehicle member is subjected to a hard coat treatment to produce a vehicle pillar.
[0006]
[Problems to be solved by the invention]
As described above, it is preferable to use a thermoplastic resin containing an inorganic fiber in order to obtain various characteristics required for an automobile member. However, when an automobile member is molded using a thermoplastic resin containing inorganic fibers, the inorganic fibers precipitate on the surface of the automobile member, resulting in a poor appearance of the automobile member, or an increase in image clarity (mirror surface). ) Is deteriorated. The phenomenon of inorganic fiber precipitation on the surface of an automobile member can be recognized by, for example, the inorganic fiber floating on the surface of the automobile member.
[0007]
At present, in order to solve the problem such as the precipitation of inorganic fibers on the surface of a molded product, the viscosity of a thermoplastic resin is reduced and the fluidity of a molten resin is improved. However, when the content of the inorganic fibers is increased, it is difficult to prevent the inorganic fibers from depositing on the surface of the molded article. Therefore, it is difficult to use a thermoplastic resin containing inorganic fibers for an automobile member requiring excellent appearance characteristics, despite having excellent performance.
[0008]
The reason why the inorganic fiber precipitates from the surface of the automobile member when the content of the inorganic fiber increases is related to the material of the mold. As described above, the mold is usually made of a metal material having good heat conductivity. Therefore, when the molten resin containing the inorganic fibers filled in the cavity comes into contact with the cavity surface of the mold, it is immediately cooled. As a result, a solidified layer is formed on the molten resin in contact with the cavity surface of the mold, and inorganic fibers are deposited. In addition, there arises a problem that transferability of the cavity surface of the mold to the surface of the automobile member is insufficient.
[0009]
In order to solve the problems described above, generally, by injecting a molten thermoplastic resin into the cavity at high pressure, the cavity surface of the mold is forcibly transferred to the surface of the molded product, Alternatively, a method has been adopted in which the mold temperature is raised to delay the development of a solidified layer in a molten thermoplastic resin. However, the former method leads to an increase in cost due to an increase in the size of the molding apparatus and an increase in the size and thickness of the mold itself, and stress remains inside the molded product due to high-pressure filling of the molten resin. The problem that the quality of goods falls is generated. In the latter method, the cooling time of the resin in the cavity becomes longer because the temperature of the mold is set close to the deflection temperature of the resin used for molding. As a result, there is a problem that a molding cycle is lengthened and productivity is reduced. Moreover, even with these molding methods, it is difficult to completely prevent the inorganic fibers from depositing on the surface of the molded article. Moreover, in a mold made of, for example, carbon steel, even if such a method is used, it is not sufficient to improve the transferability of the cavity surface of the mold or to suppress the occurrence of weld lines.
[0010]
To prevent molding defects such as weld marks and flow marks by delaying the development of a solidified layer of the resin filled in the cavity by using a non-reinforced thermoplastic resin, that is, an unreinforced thermoplastic resin. For the purpose, a technique of providing or attaching a low heat conductive material to the cavity surface of the mold is disclosed in, for example, JP-A-55-55839, JP-A-61-100425, JP-A-62-208919, It has been proposed in JP-A-5-111937, JP-A-5-200789, JP-B-6-35134, and JP-A-6-218768.
[0011]
However, when a nest having low thermal conductivity is simply attached to the cavity surface of the mold using, for example, an adhesive, the following problems occur, and practical use is difficult.
(1) When the clearance between the mold and the nest having low thermal conductivity is small, when the temperature of the mold is repeatedly increased and decreased, the coefficient of linear expansion between the material constituting the mold and the material constituting the nest is reduced. The nest breaks due to the difference.
(2) In the case where the clearance between the mold and the nest having low thermal conductivity is large, if molding is performed for a long period of time, the molten resin enters between the mold and the nest, and burrs are generated on the molded product. Then, there arises a problem that the burrs break the nest at the time of releasing the mold.
[0012]
In addition, since fine craze generated during cutting remains on the outer periphery of the nest with low thermal conductivity, cracks occur on the outer periphery of the nest due to contact with high-temperature and high-pressure molten resin, and the nest is damaged. Problems arise. Therefore, the durability of the whole mold becomes a problem, and mass production of molded products becomes difficult.
[0013]
When using a heat-resistant plastic nest to delay the development of the solidified layer, such a nest has low rigidity, and furthermore, has a poor surface hardness. There is a problem of scratching. Alternatively, there is a nest formed by forming a thin film of ceramic or the like on a metal surface by vapor deposition or the like, but there is a problem that the durability of the thin film is poor and the thin film is peeled off from the metal surface. Therefore, such a nest is used only for a test die or a simple die, and cannot withstand long-term use. Further, when a molded article is molded from a thermoplastic resin containing inorganic fibers using a mold into which these nests are incorporated, a high stress is applied to the nests due to poor fluidity of the molten resin. As a result, shortening of the life of the nest is inevitable. Furthermore, since the inorganic fiber and the nest come into contact with each other, it is necessary to impart abrasion resistance to the surface of the nest. For the above reasons, it is extremely difficult to mold a molded article based on a thermoplastic resin containing inorganic fibers using a mold incorporating these nests.
[0014]
As another method of delaying the development of the solidified layer, use high frequency, electricity, steam, etc. to raise the mold temperature before filling the molten resin into the cavity, and use water etc. to cool down in the cooling process. Methods for lowering the mold temperature are also known. However, this method has many problems such as requiring excessive facilities, inviting high costs and prolonging the molding cycle, and has not been put to practical use at present.
[0015]
Therefore, an object of the present invention is to be able to faithfully transfer the state of a mold surface of a cavity to the surface of an automobile member even when a fiber-reinforced thermoplastic resin is used, and is excellent in mirror finish, appearance, strength and heat resistance. In addition, the nest can be manufactured easily, and the nest can be easily maintained. During molding, the nest made of a low heat conductive material such as ceramic or glass does not break, and burrs are generated on the automobile member. An object of the present invention is to provide a method for molding a member for an automobile, which does not have any problem. It is a further object of the present invention to provide a method for manufacturing an automobile exterior part or an automobile pillar based on such an automobile member.
[0016]
[Means for Solving the Problems]
To achieve the above object, the method for producing a thermoplastic resin member of the present invention for an automobile,
(A) a mold for molding an automobile member, provided with a cavity;
(B) a glass or ceramic nest having a thickness of 0.5 mm to 10 mm, which is disposed inside the mold and constitutes a part of the cavity;
(C) a restraining plate which is disposed inside the mold and constitutes a part of the cavity, which restrains an end of the nest;
Consisting of
The clearance (C) between the nest and the holding plate is 0.001 mm to 0.03 mm (0.001 mm ≦ C ≦ 0.03 mm), and the holding allowance (ΔS) of the holding plate with respect to the nest is 0.1 mm. Using a mold assembly having the above (ΔS ≧ 0.1 mm), a fiber-reinforced thermoplastic resin is filled in a cavity to mold a thermoplastic resin-made automobile member.
[0017]
When the thickness of the nest is less than 0.5 mm, the heat insulating effect of the nest is reduced, and the molten resin introduced into the cavity is rapidly cooled. As a result, the development of the solidified layer cannot be suppressed, and the surface of the automobile member becomes inorganic. Fibers precipitate. Further, the probability of appearance defects such as weld marks and flow marks increases. Further, the transferability of the cavity of the nest to the surface of the vehicle member is deteriorated, and the mirror surface of the surface of the vehicle member is deteriorated. When the nest is fixed to the mold, the nest may be bonded to the mold using, for example, a thermosetting adhesive. However, when the thickness of the nest is less than 0.5 mm, the thickness of the adhesive may be reduced. When the resin is not uniform, uneven stress remains in the nest, so that the surface of the automobile member may undulate, or the nest may be damaged by the pressure of the filled molten resin. On the other hand, if the thickness of the nest exceeds 10 mm, the heat insulation effect of the nest becomes too large, and if the cooling time of the resin in the cavity is not extended, the automobile member may be deformed after removing the automobile member from the mold. There is. Therefore, a problem such as extension of the molding cycle may occur. In addition, by using such a nest, it is possible to mold an automobile member at a constant mold temperature, no special equipment is required, and the molding cycle is equivalent to that of ordinary molding. The thickness of the nest is preferably 1 mm to 7 mm, more preferably 2 mm to 5 mm.
[0018]
In the method for molding an automobile member according to the present invention, the clearance (C) between the insert and the holding plate is 0.001 mm or more and 0.03 mm or less (0.001 mm ≦ C ≦ 0.03 mm), and more preferably 0 or less. 0.003 mm to 0.03 mm (0.003 mm ≦ C ≦ 0.03 mm). Here, the clearance (C) is a gap between the nest and the holding plate measured in the thickness direction of the nest (the direction perpendicular to the cavity surface of the nest). More specifically, the minimum value of the clearance (C) is such that when the holding plate is attached, fine cracks are generated on the outer periphery of the nest, or when the nest thermally expands when the temperature of the mold rises, the nest and the holding plate become The stress may be applied to the fine cracks on the outer peripheral portion of the nest so that the nest may be damaged, or the nest may be damaged by an impact at the time of mold clamping. On the other hand, if the clearance (C) exceeds 0.03 mm, the molten resin may enter between the nest and the holding plate, causing cracks in the nest and causing burrs on automobile members. .
[0019]
When the holding allowance (ΔS) is less than 0.1 mm, the craze generated at the end of the nest during the production of the nest comes into contact with the molten resin, so that the craze grows into a crack and the nest may be damaged. The upper limit of the suppression allowance (ΔS) is not particularly limited, but is preferably about 2 mm. Here, the holding allowance (ΔS) is the distance from the end surface (side surface) of the holding plate to the end portion (side surface) of the nest measured along a direction parallel to the cavity surface of the nest.
[0020]
The clearance (D) between the nest mounting portion provided in the mold and the nest may be a value as close as possible to zero, but is practically preferably 0.005 mm or more. Here, the clearance (D) refers to the clearance between the nest mounting portion of the mold and the end surface (side surface) of the nest measured along a direction parallel to the cavity surface of the nest. Although it depends on the linear expansion coefficient of the material forming the nest, if the clearance (D) is too small, the breakage of the nest due to the difference between the linear expansion coefficient of the material forming the nest mounting portion of the mold and the material forming the nest may be reduced. It may not be possible to prevent it. Therefore, the clearance (D) may be set to a value that does not cause such a problem. Note that if the clearance (D) is too large, the nesting may be damaged due to the positional deviation of the nesting and insufficient positional stability. Therefore, the clearance (D) is preferably about 2 mm or less.
[0021]
Usually, the mold is composed of a fixed mold part and a movable mold part. Depending on the shape of the automotive member to be molded, the required surface properties, etc., the nest may be provided only on the movable mold part or may be provided only on the fixed mold part. , May be arranged in both the movable mold part and the fixed mold part. The part of the mold to which the nest is attached may be constituted by a core attached to the mold. In addition, it is preferable that the nest is disposed in a mold, for example, facing a surface portion of an automobile member requiring excellent smoothness (specularity).
[0022]
Note that forming a part of the cavity means forming a cavity surface that defines the outer shape of the member for an automobile. More specifically, the cavities include, for example, a surface forming a cavity formed in a movable mold portion and a fixed mold portion, a surface forming a cavity formed in a nest, and a cavity formed in a holding plate. And the surface that constitutes. In addition, the surface which comprises these cavities is hereafter called a cavity surface.
[0023]
It is preferable that the fiber-reinforced thermoplastic resin contains inorganic fibers. The content of the inorganic fibers is desirably 15 to 80% by weight, preferably 20 to 60% by weight. Generally, the ratio of the inorganic fibers contained in the thermoplastic resin (in other words, the ratio of the inorganic fibers added to the thermoplastic resin) is measured in accordance with a required flexural modulus (for example, in accordance with ASTM D790). Value is 4.0 GPa or more), a linear expansion coefficient, a load deflection temperature, and the like. Therefore, the value may be set to a value at which molding becomes difficult, or a member for an automobile having excellent mirror surface properties cannot be molded. Specifically, the upper limit is 80% by weight. In the case of using a crystalline thermoplastic resin, the content is 80% by weight. However, in the case of using an amorphous thermoplastic resin, the fluidity is inferior to that of the crystalline thermoplastic resin. Is 50% by weight. If the content is less than 15% by weight, the required flexural modulus cannot be obtained. If the content exceeds 80% by weight, the fluidity of the molten resin is reduced, so that molding becomes difficult, or the resin has excellent mirror surface properties. There is a possibility that a member for an automobile cannot be formed.
[0024]
The average length of the inorganic fibers is 5 μm to 400 μm, preferably 5 μm to 200 μm, and the average diameter is 0.01 μm to 15 μm, preferably 0.00.5 μm to 15 μm, and more preferably 0.1 μm to 10 μm. desirable. If the average length of the inorganic fibers is less than 5 μm and the average diameter is less than 0.01 μm, the flexural modulus required for automobile members cannot be obtained. On the other hand, if the average length of the inorganic fibers exceeds 400 μm or the average diameter exceeds 15 μm, there arises a problem that the surface of the member for automobiles is not mirror-finished.
[0025]
The average length of the inorganic fiber in the present invention means a weight average length. The length of the inorganic fiber can be measured by dissolving the resin component by immersing a thermoplastic resin pellet or an automobile member containing the inorganic fiber in a liquid that dissolves the resin component of the thermoplastic resin. The resin component is burned at a high temperature of ゜ C or higher, and the remaining inorganic fibers can be measured by observing with a microscope or the like. Normally, the length of the inorganic fiber is determined by taking a photograph of the inorganic fiber and measuring the length by a person, or by using a dedicated fiber length measuring device. It is preferable to use the weight average length because the number average length has too great an effect of the finely broken fiber. In the measurement of the weight average length, the measurement is performed except for fragments of inorganic fibers that are too small and crushed. If the length is smaller than twice the nominal diameter of the inorganic fiber, the measurement becomes difficult. Therefore, for example, an inorganic fiber having a length twice or more the nominal diameter is measured.
[0026]
The inorganic fibers having an average length and an average diameter in the above ranges are subjected to a surface treatment using a silane coupling agent or the like, then compounded with a thermoplastic resin, and pelletized into a molding material. By molding an automobile member using such a molding material and a mold assembly incorporating a nest and a holding plate, it is possible to obtain an automobile member having high rigidity and excellent mirror finish. Can be.
[0027]
The inorganic fiber is at least one selected from the group consisting of glass fiber, carbon fiber, wollastonite, aluminum borate whisker fiber, potassium titanate whisker fiber, basic magnesium sulfate whisker fiber, calcium silicate whisker fiber and calcium sulfate whisker fiber. It is preferable to be composed of one kind of material. The number of inorganic fibers contained in the thermoplastic resin is not limited to one, and two or more kinds of inorganic fibers may be contained in the thermoplastic resin.
[0028]
The thermal conductivity of the nest is 2 × 10 ^-2 It is preferably at most cal / cm · sec · deg. Nesting is wide, zirconia-based material, alumina-based material, K ₂ O-TiO ₂ Or a glass selected from the group consisting of soda glass, quartz glass, heat resistant glass, and crystallized glass, and more specifically, ZrO. ₂ , ZrO ₂ -CaO, ZrO ₂ -Y ₂ O ₃ , ZrO ₂ -MgO, K ₂ O-TiO ₂ , Al ₂ O ₃ , Al ₂ O ₃ -TiC, Ti ₃ N ₂ And 3Al ₂ O ₃ -2SiO ₂ Or a glass selected from the group consisting of soda glass, quartz glass, heat resistant glass and crystallized glass, with a thermal conductivity of 2 × 10 ^-2 cal / cm · sec · deg or less, ZrO ₂ -Y ₂ O ₃ Or 3Al ₂ O ₃ -2SiO ₂ Is preferably made of a ceramic consisting of 2 × 10 ^-2 When a nest is manufactured using a material having a thermal conductivity exceeding cal / cm · sec · deg, the molten resin in the cavity is rapidly cooled by the nest, so that the nest is manufactured from ordinary carbon steel or the like without the nest. In some cases, the same appearance as that of an automobile member molded by a molded die may be obtained, and the development of a solidified layer may not be able to be suppressed.
[0029]
Alternatively, it is preferable that the nest is made of crystallized glass having a crystallinity of 10% or more, more preferably 60% or more, more preferably 70 to 100%. When the degree of crystallinity is 10% or more, the crystals are uniformly dispersed throughout the glass, so that the thermal shock strength and the interfacial peeling property are dramatically improved, so that the occurrence of breakage of the nest at the time of molding the automotive member is significantly reduced. be able to. When the degree of crystallinity is less than 10%, there is a disadvantage that interface separation easily occurs from the surface during molding. In addition, the surface roughness R of the nested cavity surface _max Is preferably 0.03 μm or less, and the thermal shock strength is preferably 400 ° C. or more. Furthermore, the linear expansion coefficient of the crystallized glass constituting the nest is 1 × 10 ^-6 / Deg or less.
[0030]
The thermal shock strength is defined as a temperature at which a glass of 100 mm × 100 mm × 3 mm heated to a predetermined temperature is thrown into water at 25 ° C. to determine whether or not the glass is broken. The thermal shock strength of 400 ° C. means that when 100 mm × 100 mm × 3 mm glass heated to 400 ° C. is thrown into water at 25 ° C., the glass does not crack. The thermal shock strength of the heat-resistant glass is only about 180 ° C. Therefore, when the resin melted at a higher temperature (for example, about 300 ° C.) comes into contact with the nest, the nest may be distorted and the nest may be damaged. The thermal shock strength is also related to the degree of crystallinity of the glass. If the nest is made of crystallized glass having a degree of crystallization of 10% or more, the nest can be reliably prevented from being broken during molding.
[0031]
Here, crystallized glass means that a small amount of TiO ₂ And ZrO ₂ Is melted at a high temperature of 1600 ° C. or more, then molded by press, blow, roll, cast, etc., and further heat-treated for crystallization, and Li is added to the glass. ₂ O-Al ₂ O ₃ -SiO ₂ An example is a crystal in which a main crystal phase is grown and β-eucryptite-based crystals and β-spodumene-based crystals are generated. Alternatively, CaO-Al ₂ O ₃ -SiO ₂ After melting the system glass at 1400-1500 ° C., it was transferred into water and crushed to reduce the size of the particles, then accumulated, formed into a plate on a refractory setter, and further subjected to a heat treatment to obtain β-wollastonite. Examples in which a crystal phase is generated can be given. Furthermore, SiO ₂ -B ₂ O ₃ -Al ₂ O ₃ -MgO-K ₂ Heat treatment of OF-based glass to produce mica crystals, MgO-Al containing nucleating agent ₂ O ₃ -SiO ₂ An example is a glass in which cordierite crystals are generated by heat-treating a system glass. Incidentally, as the nest in the present invention, it is preferable to use a crystallized glass having a β-eucryptite-based crystal or a β-spodumene-based crystal having excellent strength and thermal properties.
[0032]
In these crystallized glasses, the ratio of crystal particles present in the glass substrate can be represented by an index called crystallinity. Then, the degree of crystallinity can be measured by measuring the ratio between the amorphous phase and the crystalline phase using an analytical instrument such as an X-ray diffractometer.
[0033]
In the case where the nest is made of ceramic, at least one thin film layer made of the material constituting the nest may be provided on the surface of the nest by a surface treatment technique such as ion plating. It can be filled, and the surface characteristics of the member for automobile can be further improved.
[0034]
When the nest is made of ceramic, a convex protrusion may be transferred to the surface of the automobile member because the nest material is porous. However, crystallized glass has advantages in that the crystal particles are fine, the adhesion between the particles is excellent, and the surface of the automobile member is easily mirrored because it is not porous.
[0035]
When the nest is made of amorphous glass such as soda glass, heat-resistant glass, and quartz glass, a thermoplastic resin (eg, polyamide 6, resin, polyamide 66 resin, polyamide MXD6 resin) having excellent affinity and adhesion to these materials is used. When molding is performed using a polyamide resin such as polyamide resin or a polyester resin such as PBT resin or PET resin), the nest and the resin are firmly adhered to each other, and when the mold is released from the mold for an automobile member, the nest becomes a surface. In some cases, there is a problem that interfacial delamination is caused from the surface. In such a case, the nest may be made of crystallized glass. Since crystallized glass has a high strength between crystal grains, interface delamination does not occur from the surface of the crystallized glass, and the problem that the nest is broken even after long-term molding is eliminated.
[0036]
When mirror surface properties are required for automobile parts, the surface roughness R of the nested cavity surface _max Is desirably 0.03 μm or less. Surface roughness R _max Exceeds 0.03 μm, the mirror finish may be insufficient, and may not satisfy the characteristics required for automotive members, for example, surface smoothness (image clarity). To do so, the surface roughness R _max Is reduced to 0.03 μm or less, for example, diamond lapping may be performed, and if necessary, lapping with cerium oxide may be performed. Lapping can be performed using a lapping machine or the like. Compared with the polishing of ordinary carbon steel or the like, for example, in the case of crystallized glass, a mirror surface can be obtained at about half the cost, so that the manufacturing cost of the mold assembly can be reduced. The surface roughness R _max Was measured according to JIS B0601. In the case of molding an automobile member having a matte or heller line surface, fine irregularities or lines may be formed on the cavity surface of the nest by sandblasting or etching the cavity surface of the nest.
[0037]
Further, the nesting is performed when the coefficient of linear expansion is 12 × 10 ^-6 It is preferable to manufacture from ceramic or glass of / deg or less. Here, the linear expansion coefficient is an average value at 50 ° C. to 300 ° C. Thereby, deformation and breakage of the nest due to expansion and contraction of different materials such as a mold and a nest can be effectively prevented. For example, when molding an automobile member by mounting a nest on a mold (or core in some cases) made of carbon steel, the mold and the mold are heated by the heat of the molten resin and the heat of water or oil of a mold temperature controller. Both nests thermally expand. Therefore, when the linear expansion coefficient exceeds the above value, unless the clearance (D) between the nest mounting portion provided on the mold and the nest is considerably increased, the nest is damaged due to the difference in the linear expansion coefficient. There are cases. When the nest is made of crystallized glass, the coefficient of linear expansion is 1 × 10 ^-6 / Deg or less.
[0038]
In the molding method of the present invention, the material constituting the nest can be easily processed to have irregularities, curved surfaces, and the like by ordinary grinding, and a nest having any shape other than a considerably complicated shape can be manufactured. A nest can be produced by placing a ceramic powder or a molten glass in a molding die, press-molding and heat-treating. In addition, a nest can be produced by naturally shaping a plate-like object made of glass in a furnace while leaving it on a jig. The lapping process can be easily performed in the final step.
[0039]
When molding an automobile member having a curved surface, the nest mounting portion of the mold is processed in accordance with the curvature of the back surface of the nest (the surface opposite to the cavity surface of the nest and facing the mold), and The holding plate may be ground in accordance with the curvature of the nested cavity surface. If such processing is not performed, the nest may be deformed and damaged by the pressure of the molten resin filled in the cavity. Also in this case, the nest is mounted on the nest mounting portion of the mold while maintaining the relationship of ΔS ≧ 0.1 mm and 0.001 mm ≦ C ≦ 0.03 mm, and the nest is suppressed by a plate.
[0040]
After processing into a predetermined shape by grinding or the like, if there is no risk that the nest will fall from the nest mounting part provided inside the mold when mounting the nest and there is no risk of breakage, or nest the nest without using an adhesive. When the nest can be mounted on the mounting portion, the nest can be directly mounted on the nest mounting portion provided inside the mold without using an adhesive. Alternatively, epoxy, urethane, acrylic, silicone ー The nest may be adhered to the nest mounting portion by using a thermosetting adhesive selected from among a variety of types. However, it is desirable to make the thickness of the adhesive as thin and uniform as possible in order to prevent the nest from being distorted due to the uneven thickness of the adhesive.
[0041]
Also, when the nest made by hot bending of the glass is mounted on the mold, the end face of the nest is inevitably not parallel to the side wall of the nest mounting part of the mold, but the nest and the nest mounting part of the mold are inevitable. The nest may be mounted on the mold with the clearance (D) between the dies being in the range of 2 mm or less, while paying attention to the occurrence of breakage of the end of the nest. It is also conceivable to grind the end face of the nest made of glass after hot bending to make it parallel to the side wall of the nest mounting part of the mold.However, since a sharply processed edge portion occurs in the nest, There is a possibility that the nest will be damaged when mounted on the mold. Therefore, it is desirable to cut the side wall of the nest mounting portion of the mold so as to be parallel to the end surface of the nest.
[0042]
Examples of thermoplastic resins suitable for use in the present invention include polyolefin resins such as polyethylene resins and polypropylene resins; styrene resins such as polystyrene resins, AS resins, ABS resins, and AES resins; methacrylic resins; polycarbonate resins; (Polyacetal) resin; polyamide resin such as polyamide 6, polyamide 66, polyamide MXD6; modified polyphenylene ether (PPE) resin; polyethylene terephthalate (PET) resin, polybutylene Conte Polyester resins such as phthalate (PBT) resins; polyphenylene sulfide resins; thermoplastic resins such as liquid crystal polymers, and polymer alloy resin compositions comprising at least two or more of these thermoplastic resins. Among them, it is preferable to use a thermoplastic resin selected from the group consisting of a polyamide resin, a polycarbonate resin, a modified polyphenylene ether resin, a polyester resin, and a polymer alloy resin composition of a polycarbonate resin / polyester resin. Stabilizers, ultraviolet absorbers, release agents, dyes and pigments may be added to the thermoplastic resin. I In some cases, an inorganic filler such as mica, kaolin, or calcium carbonate, or an organic filler may be added.
[0043]
The automotive member formed by the method for molding an automotive member of the present invention is not particularly limited, and examples thereof include automotive members for producing automotive exterior parts and automotive pillars.
[0044]
The method for manufacturing an automotive exterior component according to the present invention is characterized in that a coating film is formed on at least a part of the surface of the automotive member formed by the above-described method for forming an automotive member according to the present invention. In this case, the coating is preferably at least one type of coating selected from the group consisting of an acrylic coating, a urethane coating, and an epoxy coating. That is, after removing dust and the like from the surface of the automobile member, a paint is applied to the surface of the automobile member by brushing, spraying, electrostatic coating, a dipping method, and the like, and then dried to obtain an automobile. A coating film can be formed on at least a part of the surface of the member. It is preferable to use a coating material having a curing temperature equal to or lower than the load deflection temperature of the raw material thermoplastic resin. Since the residual strain in the automobile member is small, cracks in the automobile member due to the coating solution are less likely to occur. Examples of the automotive exterior parts include a front fender, a rear fender, a door, a bonnet, a roof, and a trunk fade. The physical property values required for the automotive parts for manufacturing the automotive exterior parts or the physical property values required for the automotive exterior parts are as shown in Table 1 below.
[0045]
[Table 1]
Flexural modulus: 4.0 GPa or more
Linear expansion coefficient: 4.0 × 10 ^-5 / Deg or less
Load deflection temperature: 100 ° C or more
Image clarity: 85% or more (for automotive parts)
[0046]
In order to satisfy these characteristics, it is preferable to use a thermoplastic resin containing an inorganic fiber satisfying the specifications shown in Table 2 below. The physical properties of the thermoplastic resin containing inorganic fibers are preferably as shown in Table 3 below.
[0047]
[Table 2]
Average length: 5-400 μm, more preferably 5-200 μm
Average diameter: 0.01 to 15 μm, preferably 0.05 to 13 μm
More preferably 0.1 to 10 μm
Content: 15 to 80% by weight, preferably 20 to 60% by weight
[0048]
[Table 3]
Flexural modulus: 4.0 GPa or more, more preferably 4.5 GPa or more
Linear expansion coefficient: 4.0 × 10 ^-5 / Deg or less, more preferably
3.5 × 10 ^-5 / Deg or less
Load deflection temperature: 100 ° C or higher, preferably 110 ° C or higher
[0049]
The method of manufacturing the automotive pillar of the present invention further includes a step of forming a hard coat layer on at least a part of the surface of the automotive member formed by the above-described method of forming an automotive member of the present invention. Features. In this case, the hard coat layer is preferably made of at least one hard coat layer selected from the group consisting of an acrylic hard coat layer, a urethane hard coat layer, and a silicone hard coat layer. That is, after removing dust and the like from the surface of the formed automobile member, a solution selected from an acrylic, urethane, or silicone hard coat solution is dipped on the surface of the automobile member, a flow coating method, A hard coat layer can be formed on at least a part of the surface of the member for an automobile by coating by a method such as a spray method and then drying and curing. The thickness of the hard coat layer on the surface of the member for automobiles is desirably 1 μm to 30 μm, preferably 3 μm to 15 μm. If it is less than 1 μm, the durability of the hard coat layer will be insufficient, and if it exceeds 30 μm, cracks will easily occur in the hard coat layer. When the adhesion between the hard coat layer and the automobile member is not sufficient, the adhesion can be improved by applying the top coat after applying the primer coat to the automobile member. Since the residual strain in the automobile member is small, cracks in the automobile member hardly occur due to the formation of the hard coat layer. Automotive pillars include automotive pillars such as front pillars, center pillars or rear pillars. Physical properties required for an automobile member (sometimes called a pillar member) for manufacturing an automobile pillar or physical properties required for an automobile pillar are as shown in Table 4 below.
[0050]
[Table 4]
Flexural modulus: 4.0 GPa or more
Linear expansion coefficient: 4.0 × 10 ^-5 / Deg or less
Load deflection temperature: 100 ° C or more
Image clarity: 80% or more (for automotive parts)
[0051]
In order to satisfy these characteristics, it is preferable to use a thermoplastic resin containing an inorganic fiber satisfying the specifications shown in Table 5 below. The physical properties required of the thermoplastic resin containing inorganic fibers are exemplified in Table 6 below.
[0052]
[Table 5]
Average length: 5-400 μm, more preferably 5-200 μm
Average diameter: 0.01 to 15 μm, preferably 0.05 to 13 μm
More preferably 0.1 to 10 μm
Content: 15 to 80% by weight, preferably 20 to 60% by weight
[0053]
[Table 6]
Flexural modulus: 4.0 GPa or more
Linear expansion coefficient: 4.0 × 10 ^-5 / Deg or less
Load deflection temperature: 100 ° C or more
[0054]
In the method of molding an automobile member of the present invention, an injection molding method, a blow molding method, and a multicolor molding method which are generally used for molding a thermoplastic resin can be given, and the most preferable method is injection molding. Is the law.
[0055]
Generally, in order to prevent the warpage of the automotive member due to the shrinkage of the resin after molding, it is necessary to consider the thermal conductivity and the thickness of the fixed mold part and the movable mold part and the nest, and to consider the automotive member. It is desirable to minimize the temperature difference between the fixed mold part and the movable mold part when taking out.
[0056]
In the method of molding a member for an automobile according to the present invention, since the mold assembly having the nest and the holding plate is used, rapid cooling of the molten resin injected or introduced into the cavity can be eased. Therefore, even at a low mold temperature, it is possible to reliably and easily mold an automobile member having excellent mirror finish. In addition, since the solidification of the molten resin is delayed, the fluidity of the resin is improved, so that even when the fiber content in the fiber-reinforced thermoplastic resin is high, it is possible to mold an automobile member, and the surface of the automobile member can be formed. Precipitation of fibers can be prevented. Further, since the flowability of the molten resin is improved, the injection pressure of the molten resin can be set low, and the stress remaining on the automobile member can be reduced. As a result, the quality of the automobile member is improved. In addition, since the injection pressure of the molten resin can be reduced, the thickness of the mold can be reduced, the size of the molding device can be reduced, and the manufacturing cost of automobile members can be reduced. Moreover, it is possible to achieve a reduction in the thickness of an automobile member, which has been considered impossible with a thermoplastic resin containing fibers.
[0057]
Especially when using plastics with good heat resistance and strength, such as engineering plastics and super engineering plastics, but poor moldability, molding is usually performed at a mold temperature of 100 ° C or higher. It is occurring frequently. However, since the heat insulating effect can be obtained by using the mold assembly according to the present invention, it is possible to obtain an automobile member having good appearance characteristics even when the mold temperature is 100 ° C. or less. In addition, even if a thermoplastic resin to which inorganic fibers are added is used, a phenomenon in which the inorganic fibers are deposited on the surface of the vehicle member does not occur, and a vehicle member having excellent appearance properties such as mirror finish can be obtained. This is because the cooling and solidification of the injected molten resin can be delayed by nesting, so that the fluidity and transferability of the molten resin can be improved.
[0058]
In addition, if the nest is made of a material having a low coefficient of thermal expansion, the nest is manufactured independently of the mold and disposed inside the mold, so that not only the heat insulation effect by the nest is large, but also the nest. Easy maintenance. If the nest is made of crystallized glass, a nest that has a low coefficient of linear expansion, is resistant to thermal shock, and is less likely to be damaged or cracked can be manufactured. By using such a nest, the heat insulation effect by the nest is large, rapid cooling of the molten resin in the cavity can be suppressed, and appearance defects such as weld marks and flow marks can be effectively prevented from occurring. . In addition, since the nesting is suppressed by the holding plate within the predetermined clearance (C) and holding allowance (ΔS), the appearance of the end of the member for the vehicle is not impaired, and the burr is added to the end of the member for the vehicle. And the molten resin does not come into contact with the fine craze remaining on the outer periphery of the nest, so that breakage of the nest can be prevented.
[0059]
【Example】
Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. In addition, the measurement of the image clarity of the automotive member molded in the Examples and Comparative Examples was performed using a surface image clarity measuring device (manufactured by Suga Test Instruments: ICP-2DP) under the conditions shown in Table 7 below. As a measurement site, a site having a large curvature was selected, and a car member was cut and measured. Further, at the time of measurement, the measurement site was measured as close to a plane as possible using a 3 kg sample holder. Ten points were measured and the average value was determined. Further, regarding the physical properties of the automotive member, the coefficient of linear expansion was measured based on ASTM D696, and the deflection temperature under load was measured based on ASTM D648 under a load of 455 kPa.
[0060]
[Table 7]
Measuring range: 20mm diameter
Incident and light receiving angle: 60 degrees
Optical comb width: 0.5mm
[0061]
(Example 1)
Example 1 and Example 2 described below relate to a method for forming an automobile member and a method for manufacturing an exterior component for an automobile. FIG. 1A is a schematic partial end view showing a specific example of a mold assembly suitable for carrying out the method for molding an automobile member according to the first embodiment. 1 (B) and 1 (C) are schematic end views of the mold assembly being assembled. The mold assembly is assembled in the order of FIG. 1 (B), FIG. 1 (C), and FIG. 1 (A).
[0062]
In Example 1, the nest 30 was manufactured using crystallized glass (crystallinity: 70%) whose characteristic values are shown in Table 8 below. The shape of the nest 30 is a flat plate having a thickness of 4.00 mm, a length of 471.00 mm, and a width of 451.00 mm.
[0063]
[Table 8]

[0064]
The size of the cavity 40 in the mold assembly of Example 1 was 470.00 mm × 450.00 mm × 3.00 mm, and the shape was a rectangular parallelepiped. The fixed mold part 10 was made of carbon steel S55C. The part of the fixed mold part 10 to which the nest 30 is mounted was constituted by a core 12 made of carbon steel S55C. The core 12 was cut so that the inner size of the nesting portion 11 was 471.20 mm × 451.20 mm and the depth was 4.02 mm.
[0065]
The insert 30 was fixed in the insert mounting portion 11 of the core 12 using a two-part curing type epoxy adhesive (not shown) (see FIG. 1B). Thereafter, the cavity surface 31 of the nest 30 is polished and finished using a diamond grindstone and a cerium oxide grindstone to obtain a surface roughness R of the cavity surface 31 of the nest 30. _max Was set to 0.02 μm. When the clearance (D) between the nesting 30 and the nesting portion 11 was measured using a gap gauge, the minimum clearance was 0.05 mm. Next, the core 12 was attached to the fixed mold part 10.
[0066]
The holding plate 32 was made from carbon steel S55C. The inner dimension of the holding plate 32 was 470.00 mm × 450.00 mm. The holding plate 32 was fixed to the fixed mold part 10 using screws (not shown) (see FIG. 1C). The clearance (C) between the nest 30 and the holding plate 32 was 0.019 mm on average. Further, the holding allowance (ΔS) of the holding plate 32 with respect to the insert 30 was 0.5 mm. The illustration of the gate portion is omitted in FIG.
[0067]
On the other hand, the movable mold part 20 was made of carbon steel S55C. Then, the movable mold part 20 and the fixed mold part 10 shown in FIG. 1C were assembled to complete a mold assembly (see FIG. 1A).
[0068]
After the completed mold assembly was attached to the molding apparatus, the mold assembly was heated to 130 ° C. using a mold temperature controller, and then rapidly cooled to 40 ° C., but was manufactured from crystallized glass. No damage such as cracks occurred in the insert 30.
[0069]
Using a 550MM injection molding device manufactured by Mitsubishi Heavy Industries, Ltd. as the injection molding device, the mold assembly was heated to 80 ° C. The interior of the cavity 40 was completely filled with a thermoplastic resin made of a polycarbonate resin containing 20% by weight of inorganic fibers made of aluminum borate whisker fibers shown in Table 9 below and under the injection molding conditions shown in Table 9 below. A sufficient amount of molten resin to be charged into the cavity 40 was injected into the cavity 40 through the gate 13. Then, 20 seconds after the completion of the injection, the automobile member was taken out of the mold assembly.
[0070]
[Table 9]
Aluminum borate whisker fiber
Average length: 10 μm
Average diameter: 0.1 μm
Molding condition
Mold temperature: 80 ° C
Resin temperature: 310 ° C
Injection pressure: 500kgf / cm ² -G
[0071]
The surface of the automobile member (the surface that was in contact with the insert 13) had a mirror surface up to its end despite the low mold temperature. As a result of measuring the smoothness of the surface of the automobile member using a surface mapping measuring instrument, it was found that the member had a very high specularity of 95% with respect to 100% of a perfect mirror surface. In addition, when the physical properties of the automobile member were measured, the flexural modulus was 6.0 GPa and the coefficient of linear expansion was 2.5 × 10 ^-5 / Deg and the load deflection temperature of 145 ° C., indicating that it has the desired performance. Further, the molding was continuously performed for 10,000 cycles, but no damage such as cracks occurred in the insert 30.
[0072]
After the surface of the molded automobile member was coated with a urethane-based coating by a spray method, the coating was cured in an oven at 140 ° C. for 2 hours. As a result, the subject was clearly projected, and an automobile exterior part excellent in image clarity was obtained. In addition, the molding cycle of the automobile member was about 40 seconds / piece, and the mass production was excellent.
[0073]
(Comparative Example 1A)
In Comparative Example 1A, a mold was prepared from a Starbucks steel, and a mold assembly in which the cavity surface of the mold was mirror-polished was used. The structure of the mold assembly of Comparative Example 1A is the same as that of Example 1 except that it does not include a nest and a holding plate as shown in a schematic partial end view of FIG. It has the same structure as the mold assembly. Then, using the same thermoplastic resin as in Example 1, molding was performed under the same molding conditions as in Example 1. As a result, the fluidity of the molten resin in the cavity was poor, and the cavity could not be completely filled with the molten resin. Therefore, the injection pressure is set to 200 kgf / cm ² -G increase, 700kgf / cm ² Molding was performed as -G. Inorganic fibers were precipitated on the surface of the obtained automobile member, and the appearance was very poor. When the surface smoothness of the automobile member was measured with a surface image clarity measuring instrument, it was 7% with respect to 100% of the complete mirror surface, and the mirror surface property was significantly lower than that of the automobile member of Example 1.
[0074]
(Comparative Example 1B)
In Comparative Example 1B, as shown in a schematic partial end view in FIG. 3B, a mold assembly having a structure without using a holding plate was used. Then, using the same thermoplastic resin as in Example 1, molding was performed under the same molding conditions as in Example 1. As a result, the appearance of the end portion of the automobile member was inferior, and poor appearance such as burrs occurred. In addition, cracks occurred at the end of the insert 30 in 15 cycles of molding.
[0075]
(Comparative Example 1C)
In Comparative Example 1C, in the mold assembly used in Example 1, the clearance (C) between the holding plate 32 and the insert 30 was 0.04 mm. Then, using the same thermoplastic resin as in Example 1, molding was performed under the same molding conditions as in Example 1. As a result, the molten resin penetrated into the gap between the holding plate 32 and the insert 30, and the automobile member could not be removed from the mold assembly at the time of release.
[0076]
(Comparative Example 1D)
In Comparative Example 1D, in the mold assembly used in Example 1, the holding allowance (ΔS) of the holding plate 32 with respect to the insert 30 was 0.05 mm. Then, using the same thermoplastic resin as in Example 1, molding was performed under the same molding conditions as in Example 1. As a result, cracks grew from the outer periphery of the nest, and cracks occurred on the entire surface of the nest 30 in the fifth cycle of molding.
[0077]
(Example 2)
In Example 2, the same mold assembly as in Example 1 was used. As the thermoplastic resin, a polycarbonate resin containing 50% by weight of a glass fiber subjected to a silane coupling treatment as an inorganic fiber was used. The average length of the glass fiber was 70 μm, and the average diameter was 10 μm. The molding conditions were the same as in Example 1 except that the resin temperature was raised to 330 ° C. Table 10 shows the results of measurement of surface smoothness and physical properties of the automotive member before coating, which were performed in the same manner as in Example 1, using a surface image clarity measuring device. The surface of the molded automobile member was coated with a urethane-based paint by a spray method, and then cured in an oven at 140 ° C. for 2 hours. As a result, the subject was clearly projected, and an automobile exterior part excellent in image clarity was obtained.
[0078]
(Comparative Examples 2A to 2C)
In Comparative Examples 2A to 2C, the same mold assembly as in Example 1 was used. As the thermoplastic resin, a polycarbonate resin containing silane-coupled glass fiber as an inorganic fiber was used. Table 10 shows the specifications of the thermoplastic resin used. Table 10 shows the measurement results of surface smoothness and physical properties of the automotive member obtained under the same molding conditions as in Example 2. In Table 10, the fiber length and the fiber diameter mean the average length and the average diameter of the fiber. The unit of the linear expansion coefficient is 10 ^-5 / Deg.
[0079]
[Table 10]

[0080]
As is clear from Comparative Examples 2B and 2C, when the average length of the inorganic fibers exceeds 400 μm, the image clarity decreases. Further, as is apparent from Comparative Example 2A, when the content of the inorganic fibers is less than 15% by weight, the linear expansion coefficient (3.0 × 10 ^-5 / Deg or less) and flexural modulus.
[0081]
(Example 3)
Example 3 and Example 4 described below relate to a method of forming an automobile member and a method of manufacturing an automobile pillar. FIGS. 2A, 2B, and 2C are schematic partial end views of the mold assembly used in the third embodiment. In the third embodiment, the nest 130 was manufactured and mounted as shown in FIG. A nest 130 was produced from a flat crystallized glass (crystallinity: 70%) having a thickness of 4.5 mm, a length of 275.0 mm, and a width of 85.0 mm. The properties of the crystallized glass are the same as those of the crystallized glass used in Example 1. Then, the plate-shaped crystallized glass was placed on a ceramic mold having a radius of curvature of 500 mm in a high-temperature furnace at 800 ° C., and was naturally shaped, followed by grinding. Thereafter, the cavity surface 131 of the nest 130 is polished and finished using a diamond grindstone and a cerium oxide grindstone to obtain a surface roughness R of the nest cavity surface 131. _max Was set to 0.02 μm. The final size of the insert 130 was 4.00 mm in thickness, 271.00 mm in length, and 81.00 mm in width. The radius of curvature of the cavity surface 131 of the nest 130 is 500 mm.
[0082]
The inner dimension of the nesting portion 111 provided on the fixed mold portion 110 was 271.20 mm × 81.20 mm. The nesting portion 111 has the same shape as the surface of the nesting 130 opposite to the cavity surface 131. Next, the nest 130 was fixed in the nest mounting portion 111 with an epoxy-based adhesive (not shown) (see FIG. 2B). When the clearance (D) between the nest 130 and the nest mounting portion 111 was measured using a gap gauge, the minimum clearance was 0.05 mm.
[0083]
Next, as shown in FIG. 2C, a holding plate 132 was manufactured. The holding plate 132 was made of carbon steel S55C. The inner dimension of the holding plate 132 was 270.00 mm × 80.00 mm. The radius of curvature of the surface of the holding plate 132 facing the cavity surface 131 of the nest 130 was 500 mm. Next, the holding plate 132 was fixed to the fixed mold part 110 using screws (not shown). The clearance (C) between the nest 130 and the holding plate 132 was 0.019 mm on average. The holding allowance (ΔS) of the holding plate 132 with respect to the insert 130 was 0.5 mm.
[0084]
Next, as shown in FIG. 2A, the movable mold part 120 and the fixed mold part 110 were assembled to complete a mold assembly. The dimensions of the vehicle pillar are 270 mm in length, 80 mm in width, 2 mm in thickness, and the radius of curvature of the surface is 500 mm. The completed mold assembly was attached to an injection molding device. After heating to 130 ° C. using a mold temperature controller and then rapidly cooling to 40 ° C., no problems such as cracks occurred in the insert 130 made of crystallized glass.
[0085]
The mold assembly was heated to 80 ° C. using a 150 MST injection molding device manufactured by Mitsubishi Heavy Industries, Ltd. as the injection molding device. The interior of the cavity 140 was completely filled with a thermoplastic resin made of a polycarbonate resin containing 20% by weight of an inorganic fiber made of aluminum borate whisker fibers shown in Table 11 below and under the injection molding conditions shown in Table 11 below. A sufficient amount of molten resin to be charged into the cavity 140 was injected into the cavity 140 through the gate portion 113. Then, 20 seconds after the completion of the injection, the automobile member (pillar member) was taken out of the mold assembly.
[0086]
[Table 11]
Aluminum borate whisker fiber
Average length: 10 μm
Average diameter: 0.1 μm
Molding condition
Mold temperature: 80 ° C
Resin temperature: 310 ° C
Injection pressure: 500kgf / cm ² -G
[0087]
The surface of the automotive member (the surface that was in contact with the insert 130) had a mirror surface up to the end of the automotive member despite the low mold temperature. As a result of measuring the smoothness of the surface of the automobile member using a surface mapping measuring instrument, it was found that the member had a very high specularity of 95% with respect to 100% of a perfect mirror surface. In addition, when the physical properties of the automobile member were measured, the flexural modulus was 6.0 GPa and the coefficient of linear expansion was 2.5 × 10 ^-5 / Deg and the load deflection temperature of 145 ° C., indicating that it has the desired performance. The molding was further continuously performed for 10,000 cycles, but no damage such as cracks occurred in the insert 130.
[0088]
After an acrylic hard coat solution was applied to the formed automobile member (pillar member) by a dipping method, the hard coat solution was completely cured by an ultraviolet irradiation machine to complete an automobile pillar. The completed automobile pillar has a very beautiful appearance, almost the same appearance as an automobile pillar molded from a thermoplastic resin containing no inorganic fiber, and furthermore, an automobile pillar No cracks occurred.
[0089]
(Comparative Example 3A)
In Comparative Example 3A, a mold was prepared from a Starbucks steel mold, and a mold assembly in which the cavity surface of the mold was mirror-polished was used. The structure of the mold assembly of Comparative Example 3A has the same structure as that of the mold assembly of Example 3 except that the mold assembly is not provided with a nest and a holding plate. Then, using the same thermoplastic resin as in Example 3, molding was performed under the same molding conditions as in Example 3. As a result, the fluidity of the molten resin in the cavity was poor, and the cavity could not be completely filled with the molten resin. Therefore, the injection pressure is set to 200 kgf / cm ² -G increase, 700kgf / cm ² Molding was performed as -G. On the surface of the obtained automobile member (pillar member), inorganic fibers were precipitated, and the appearance was very poor. When the surface smoothness of the automobile member was measured with a surface image clarity measuring device, it was 7% with respect to 100% of the complete mirror surface, and the mirror surface property was significantly lower than that of the automobile member of Example 3. As a result of performing the hard coat treatment on this automobile member in the same manner as in Example 3, the appearance of the surface of the obtained automobile member was inferior, and cracks were generated from the end of the automobile member.
[0090]
(Comparative Example 3B)
In Comparative Example 3B, a mold assembly having a structure in which the insert 130 was not held down by a holding plate was used. Then, using the same thermoplastic resin as in Example 3, molding was performed under the same molding conditions as in Example 3. As a result, the appearance of the end portion of the automobile member was inferior, and poor appearance such as burrs occurred. In addition, cracks occurred at the end of the insert 130 in 15 cycles of molding.
[0091]
(Comparative Example 3C)
In Comparative Example 3C, in the mold assembly used in Example 3, the clearance (C) between the holding plate 132 and the insert 130 was 0.04 mm. Then, using the same thermoplastic resin as in Example 3, molding was performed under the same molding conditions as in Example 3. As a result, the molten resin intruded into the gap between the holding plate 132 and the insert 130, and the automobile member could not be removed from the mold assembly during release.
[0092]
(Comparative Example 3D)
In Comparative Example 3D, in the mold assembly used in Example 3, the holding allowance (ΔS) of the holding plate 132 with respect to the insert 130 was set to 0.05 mm. Then, using the same thermoplastic resin as in Example 3, molding was performed under the same molding conditions as in Example 3. As a result, cracks grew from the outer periphery of the nest, and cracks occurred on the entire surface of the nest at the fifth cycle of molding.
[0093]
(Example 4)
In Example 4, the same mold assembly as in Example 3 was used, and molding was performed using a thermoplastic resin obtained by adding 50% by weight of silane-coupled glass fiber as an inorganic fiber to a polycarbonate resin. . The average length of the inorganic fibers was 70 μm, and the average diameter was 10 μm. The molding conditions were the same as in Example 3 except that the resin temperature was raised to 330 ° C. of Molding was performed under the conditions. After an acrylic hard coat solution was applied to the formed automobile member (pillar member) by a dipping method, the hard coat solution was completely cured by an ultraviolet irradiation machine to complete an automobile pillar. The completed automobile pillar has a very beautiful appearance, almost the same appearance as an automobile pillar molded from a thermoplastic resin containing no inorganic fiber, and furthermore, an automobile pillar No cracks occurred. Table 12 shows the results of measuring the surface smoothness of the automobile member (pillar member) obtained in Example 4 with a surface image clarity measuring device and the physical property measurement results. In Table 12, the fiber length and the fiber diameter mean the average length and the average diameter of the fiber. The unit of the linear expansion coefficient is 10 ^-5 / Deg.
[0094]
(Comparative Examples 4A to 4C)
In Comparative Examples 4A to 4C, the same mold assembly as in Example 3 was used, and molding was performed using a thermoplastic resin obtained by adding silane-coupled glass fiber as an inorganic fiber to a polycarbonate resin. Was. Table 12 shows the average length and average diameter of the fiber. The molding conditions were the same as in Example 4. Table 12 shows the results of measuring the smoothness of the surface of the automobile member (pillar member) using a surface mapping measuring instrument and the results of measuring the physical properties. Same as Example 4 Deposit In spite of molding using the mold assembly, in Comparative Examples 4B and 4C, the average length of the inorganic fibers was too long, and the image clarity was insufficient. In Comparative Example 4A, the content of the inorganic fiber was less than 15% by weight, and the coefficient of linear expansion (3.0 × 10 ^-5 / Deg or less) and flexural modulus were not satisfied.
[0095]
[Table 12]

[0096]
Although the present invention has been described based on the preferred embodiments, the present invention is not limited to these embodiments. The conditions and materials used in the embodiments are merely examples, and the structure of the mold assembly is also an example, and can be changed as appropriate. The shapes and sizes of the nesting and the holding plate are also examples, and the design can be changed as appropriate depending on the shape of the automotive member to be molded. The nest may be disposed in the mold so as to face a portion of the surface of the automobile member that requires mirror surface properties, and may be provided in the movable mold portion or the fixed mold portion as necessary. And the movable mold part.
[0097]
【The invention's effect】
According to the method for molding an automobile member of the present invention, by using a mold assembly having a nest and a holding plate, it has a high modulus of elasticity, a low coefficient of linear expansion, high heat resistance, and is extremely excellent. It is possible to form an automobile member having a mirror surface.
[0098]
Furthermore, in the method of molding a member for an automobile according to the present invention, long-term molding is performed by suppressing the nesting with a restraining plate within a range of a predetermined clearance (C) and a restraining allowance (ΔS). Thus, it is possible to easily and inexpensively manufacture an automobile member having a mirror surface without causing damage to the nest. Further, the appearance of the end portion of the automobile member is not impaired, the occurrence of burrs at the end portion of the automobile member can be prevented, the defect rate reduction and homogenization of the automobile member, and high quality can be achieved. It is possible to reduce the manufacturing cost of a member for an automobile.
[0099]
Further, since the flowability of the molten resin is improved, the injection pressure of the molten resin can be set low, so that the stress remaining on the automobile member can be reduced, and the quality of the automobile member is improved. Furthermore, since the injection pressure of the molten resin can be reduced, the thickness of the mold can be reduced, the size of the molding apparatus can be reduced, and the cost of automobile members can be reduced. In addition, by manufacturing a nest from crystallized glass, an automobile member having excellent mirror-like properties and transferability can be easily obtained. If the nest is made of crystallized glass, it is possible to produce a nest having a low coefficient of linear expansion, strong resistance to thermal shock, and hardly causing breakage or cracking.
[0100]
According to the method for manufacturing an automobile exterior component of the present invention, by applying a coating to the surface of an automobile member obtained by molding a fiber-reinforced thermoplastic resin, high rigidity, low linear expansion coefficient, and high heat resistance are obtained. Thus, an exterior component for an automobile having excellent appearance can be obtained. In addition, it is possible to improve the mass productivity and the degree of freedom in design in the production of exterior parts for automobiles having excellent appearance and reduced weight.
[0101]
In addition, according to the method for manufacturing an automotive pillar of the present invention, a surface of an automotive member obtained by molding a fiber-reinforced thermoplastic resin is subjected to a hard coat treatment, so that high rigidity, low linear expansion coefficient, and high heat resistance are obtained. An automotive pillar having excellent properties and excellent appearance can be obtained. In addition, it is possible to suppress the occurrence of cracks in the automotive member due to the hard coat solution.
[Brief description of the drawings]
FIG. 1 is a schematic partial end view of a preferred embodiment of a mold assembly suitable for carrying out Example 1, and a schematic partial end view of the mold assembly during assembly.
FIG. 2 is a schematic partial end view of a preferred embodiment of a mold assembly suitable for carrying out Example 2, and a schematic partial end view of the mold assembly during assembly.
FIG. 3 is a schematic partial end view of a mold assembly in a comparative example.
[Explanation of symbols]
10,110 Fixed mold part
11.111 Nested part
12 core
13,113 Gate
20,120 Movable mold part
30,130 nesting
31,131 Nested cavity surface
32,132 Holding plate
40,140 cavity

Claims (21)

A method for producing a thermoplastic resin exterior component,
(A) a mold for molding an automobile member, provided with a cavity;
(B) a glass or ceramic nest having a thickness of 0.5 mm to 10 mm, which is disposed inside the mold and constitutes a part of the cavity;
(C) a restraining plate which is disposed inside the mold and constitutes a part of the cavity, which restrains an end of the nest;
Consisting of
Fiber-reinforced thermoplastic resin using a mold assembly in which the clearance between the nest and the holding plate is 0.001 mm or less and 0.03 mm or less, and the holding allowance of the holding plate for the nest is 0.1 mm or more. the after forming an automotive member made of thermoplastic resin by filling the cavity, the production method of the external part of a motor vehicle and forming the coating on at least a portion of the surface of the automobile member. The method for manufacturing an exterior component for an automobile according to claim 1, wherein the fiber-reinforced thermoplastic resin contains an inorganic fiber. 3. The method according to claim 2, wherein the content of the inorganic fibers is 15% by weight to 80% by weight. Average length of the inorganic fibers is 5μm to 400 [mu] m, average diameter automotive exterior parts method as claimed in claim 2 or claim 3, characterized in that a 0.01μm to 15 [mu] m. The inorganic fiber is selected from the group consisting of glass fiber, carbon fiber, wollastonite, aluminum borate whisker fiber, potassium titanate whisker fiber, basic magnesium sulfate whisker fiber, calcium silicate whisker fiber and calcium sulfate whisker fiber. The method for manufacturing an exterior component for an automobile according to any one of claims 2 to 4, wherein the method comprises at least one kind of material. Automotive exterior parts manufacturing method according to any one of claims 1 to 5, wherein the surface roughness R _max of the surface constituting the nest of the cavity is less than 0.03 .mu.m. 7. The method for manufacturing an automotive exterior part according to claim 1, wherein the nest has a thermal conductivity of 2 × 10 ⁻² cal / cm · sec · deg or less. The nests are ZrO ₂ , ZrO ₂ -CaO, ZrO ₂ -Y ₂ O ₃ , ZrO ₂ -MgO, K ₂ O-TiO ₂ , Al ₂ O ₃ , Al ₂ O ₃ -TiC, Ti ₃ N ₂ , 3Al ₂ O ₃ ceramic selected from the group consisting of -2SiO _2, or 1 to claim, characterized in that soda glass, quartz glass, heat resistant glass, and is fabricated from a glass selected from the group consisting of crystallized glass A method for manufacturing an automotive exterior component according to claim 7. The thermoplastic resin is a thermoplastic resin selected from the group consisting of a polyamide resin, a polycarbonate resin, a modified polyphenylene ether resin, a polyester resin, and a polymer alloy resin composition of a polycarbonate resin / polyester resin. The method for manufacturing an exterior component for an automobile according to any one of claims 1 to 8 , wherein: 10. The coating film according to claim 1 , wherein the coating film is at least one paint film selected from the group consisting of an acrylic paint film, a urethane paint film, and an epoxy paint film. 3. The method for manufacturing an automotive exterior component according to 1. The method for manufacturing an automobile exterior component according to any one of claims 1 to 10, wherein the automobile exterior component is a front fender, a rear fender, a door, a hood, a roof, or a trunk fade. . A method for manufacturing a thermoplastic automotive pillar,
(A) a mold for molding an automobile member having a cavity,
(B) a thickness of 0.5 mm or more, which is arranged inside the mold and constitutes a part of the cavity; A 10 mm glass or ceramic nest;
(C) a suppressing plate which is disposed inside the mold and constitutes a part of the cavity, which suppresses an end of the nest;
Consisting of
Fiber-reinforced thermoplastic resin using a mold assembly in which the clearance between the nest and the holding plate is 0.001 mm or less and 0.03 mm or less, and the holding allowance of the holding plate for the nest is 0.1 mm or more. A vehicle member made of a thermoplastic resin by filling the inside of the cavity with a resin, and then obtaining a vehicle pillar by forming a hard coat layer on at least a part of the surface of the vehicle member. Method of manufacturing pillars. The method according to claim 12, wherein the fiber-reinforced thermoplastic resin contains inorganic fibers. 14. The method according to claim 13, wherein the content of the inorganic fibers is 15 wt% to 80 wt%. The method according to claim 13, wherein the inorganic fibers have an average length of 5 μm to 400 μm and an average diameter of 0.01 μm to 15 μm. The inorganic fiber is selected from the group consisting of glass fiber, carbon fiber, wollastonite, aluminum borate whisker fiber, potassium titanate whisker fiber, basic magnesium sulfate whisker fiber, calcium silicate whisker fiber and calcium sulfate whisker fiber. The method according to any one of claims 13 to 15, further comprising at least one kind of material. Surface roughness R of the surface constituting the nested cavity _max The method according to any one of claims 12 to 16, wherein is less than or equal to 0.03 µm. The thermal conductivity of the nest is 2 × 10 ^-2 The method according to any one of claims 12 to 17, wherein the value is not more than cal / cm · sec · deg. Nesting is ZrO _Two , ZrO _Two -CaO, ZrO _Two -Y _Two O _Three , ZrO _Two -MgO, K _Two O-TiO _Two , Al _Two O _Three , Al _Two O _Three -TiC, Ti _Three N _Two , 3Al _Two O _Three -2SiO _Two 19. A ceramic selected from the group consisting of: or a glass selected from the group consisting of soda glass, quartz glass, heat resistant glass, and crystallized glass. 4. The method for manufacturing a vehicle pillar according to claim 1. The thermoplastic resin is a thermoplastic resin selected from the group consisting of a polyamide resin, a polycarbonate resin, a modified polyphenylene ether resin, a polyester resin, and a polymer alloy resin composition of a polycarbonate resin / polyester resin. The method for manufacturing a vehicle pillar according to any one of claims 12 to 19, characterized in that: The hard coat layer comprises at least one hard coat layer selected from the group consisting of an acrylic hard coat layer, a urethane hard coat layer, and a silicone hard coat layer. Item 21. The method for manufacturing a vehicle pillar according to any one of items 20.

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