JP2004197132A

JP2004197132A - Resin-coated magnesium alloy sheet and method for producing formed body formed from resin-coated magnesium alloy sheet, and portable instrument boxed body

Info

Publication number: JP2004197132A
Application number: JP2002364641A
Authority: JP
Inventors: Keiichi Shimizu; 慶一志水; Kengo Iwanaga; 健吾岩永; Hiroaki Okamoto; 浩明岡本
Original assignee: Toyo Kohan Co Ltd
Current assignee: Toyo Kohan Co Ltd
Priority date: 2002-12-17
Filing date: 2002-12-17
Publication date: 2004-07-15

Abstract

<P>PROBLEM TO BE SOLVED: To provide an unexpensive resin-coated magnesium alloy sheet having excellent formability, particularly press-formability, and a method for producing this alloy sheet and a portable instrument boxed body. <P>SOLUTION: The magnesium alloy sheet contains 1.5-5.5 wt% Al, 0.5-1.5 wt% Zn, ≥0.05 wt% Mn, ≤0.3 wt% Fe and the balance Mg with inevitable impurities, and an X-ray intensity ratio with an X-ray diffraction [X-ray intensity at (0002) plane]/[X-ray intensity at (101(upper bar) 1 ) plane] is 1.0-3.5, and on at least one side surface, a resin film easily detachable is coated. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、成形性、特に室温から２００℃近傍の準温間域におけるプレス成形性に優れた安価な樹脂被覆マグネシウム合金板、当該樹脂被覆マグネシウム合金板から成形する成形体の製造方法および携帯機器筐体に関する。
【０００２】
【従来の技術】
従来、マグネシウム合金板は、厚み数ｍｍ〜数十ｍｍの鋳造スラブ、あるいは押し出しによる厚板を繰り返し熱処理、熱間圧延、温間圧延することにより薄板とされている。このように繰り返し熱処理、熱間圧延、温間圧延等を施すことによって製造される薄マグネシウム合金板は、室温〜準温間域での温度、すなわち冷間での加工性が劣ると共に、経済性の点でも割高であり、広く使用されるに至ってない。
【０００３】
近年、マグネシウム合金は、Ａｌよりも比重が小さく、非剛性が高く、また、軽量化できるものであるために、安価で、成形性に優れたマグネシウム合金板に対する要求が高まって来ている。そこで、プレス成形性に優れたマグネシウム合金として、プレス成形性を改善するための組成や圧延条件について提案されている（例えば、特許文献１参照）。また、マグネシウムにリチウムを添加し、ｈｃｐ構造のα相中にｂｃｃ構造のβ相を１部生成させたり、あるいはβ単相にすることにより冷間における延性や曲げ加工性を改善することが提案されている（例えば、特許文献２参照）が、リチウムは活性な金属であるため工業的に大量に取り扱うには安全上問題があるばかりでなく、高価でマグネシウムの耐食性を著しく低下させるという問題点がある。
【０００４】
更に、マグネシウムの熱間加工で提案されているものがあるが、結晶粒微細化を目的とし大ひずみを付与する加工法や条件を検討したものが開示されていて、結晶粒径が１μｍ以下に微細化されているが成形性の改善については言及されてない（例えば、特許文献４参照）。また、形状が限定されるあるいは熱間鍛造を繰り返し行う必要があり、薄肉のマグネシウム合金板は作製できない。
【０００５】
また、潤滑油を使った加工は、特殊な潤滑油が必要となり、また、その後の脱脂が必要となる。また、通常の脱脂では、潤滑油の除去が困難で、多くの問題点を伴う。
【０００６】
本出願に関する先行技術文献情報として次のものがある。
【０００７】
【特許文献１】
特開平６−２９３９４４号公報
【特許文献２】
特開平６−２５７８８号公報
【特許文献３】
特開平９−４１０６６号公報
【特許文献４】
特開２０００−２７１６９３号公報
【０００８】
【発明が解決すべき課題】
本発明はこれらの点に鑑みてなされたものであり、加工性、特に室温から準温間域における深絞り加工性などのプレス成形性に優れ、加工後の脱脂を簡略化でき、かつ、経済性の点でも安価な樹脂被覆マグネシウム合金板、樹脂被覆マグネシウム合金板から成形する成形体の製造方法および携帯機器筐体を提供することを目的とする。
【０００９】
【課題を解決するための手段】
そこで、本発明者は、鋭意検討した結果、下記の樹脂被覆マグネシウム合金が加工性に優れ、その後の脱脂を簡略化できることを見いだした。
【００１０】
請求項１記載の樹脂被覆マグネシウム合金板は、マグネシウム合金板の少なくとも片面に易剥離性を有する樹脂フィルムを被覆してなることを特徴とする。前記マグネシウム合金板は、Ａｌを１．５〜５．５重量％、Ｚｎを０．５〜１．５重量％、Ｍｎを０．０５重量％以上、Ｆｅを０．３重量％以下含有し、残部がＭｇ及び不可避の不純物からなることが望ましい。また、前記マグネシウム合金板は、Ｘ線回折でのＸ線強度比［（０００２）面のＸ線強度］／［（１０１（上バー）１）面のＸ線強度］が１．０〜３．５であることが望ましい。
【００１１】
一方、前記易剥離性を有する樹脂フィルムは、ポリエステル樹脂、ポリ４フッ化エチレン樹脂、ポリエチレン樹脂あるいはポリエチレン樹脂とポリプロピレン樹脂の２層からなる樹脂であることが望ましい。この場合、前記易剥離性を有する樹脂フィルムは、マグネシウム合金板との接着強度がＴピール強度で０．５ｋｇ／ｃｍ以下であることが望ましい。
【００１２】
請求項６記載の樹脂被覆マグネシウム合金板から成形する成形体の製造方法は、マグネシウム合金板の少なくとも片面に易剥離性を有する樹脂フィルムを被覆し、常温〜該樹脂フィルムの融点未満に加熱し、成形加工後、該樹脂フィルムを剥離することを特徴とする。この場合、前記マグネシウム合金板は、Ａｌを１．５〜５．５重量％、Ｚｎを０．５〜１．５重量％、Ｍｎを０．０５重量％以上、Ｆｅを０．３重量％以下含有し、残部がＭｇ及び不可避の不純物からなることが望ましい。また、前記マグネシウム合金板は、Ｘ線回折でのＸ線強度比［（０００２）面のＸ線強度］／［（１０１（上バー）１）面のＸ線強度］が１．０〜３．５であることが望ましい。
【００１３】
一方、前記易剥離性を有する樹脂フィルムは、ポリエステル樹脂、ポリ４フッ化エチレン樹脂、ポリエチレン樹脂あるいはポリエチレン樹脂とポリプロピレン樹脂の２層からなる樹脂であることが望ましい。また、前記易剥離性を有する樹脂フィルムは、マグネシウム合金板との接着強度がＴピール強度で０．５ｋｇ／ｃｍ以下であることが望ましい。
【００１４】
請求項１１記載の携帯機器筐体は、請求項１乃至請求項５のいずれか１項に記載の樹脂被覆マグネシウム合金板を用いて形成されていることを特徴とする。
【００１５】
請求項１２記載の携帯機器筐体は、請求項６乃至請求項１０のいずれか１項に記載の樹脂被覆マグネシウム合金板から成形する成形体の製造方法を用いて形成されていることを特徴とする。
【００１６】
【発明の実施の形態】
上記したマグネシウム合金板は、Ａｌを２．０〜５．０重量％、Ｚｎを０．５〜２．０重量％、Ｍｎを０．０５重量％以上、Ｆｅを０．３重量％以下を含有し、残部がＭｇ及び不可避の不純物からなる成分を有し、その表面に易剥離性を有する樹脂フィルムが被覆されていて、加工性、特に室温〜準温間におけるプレス成形性に優れ、脱脂を簡略化でき、経済的に優れるのである。各成分の適正な濃度範囲等は下記の通りである。
【００１７】
［Ａｌ量］
Ａｌ量は、添加量が多いほど、強度を改善する効果があり、強度の点で、１．５重量％以上添加する必要がある。５．５重量％を超えると、晶出物が溶体化せず、脆化し、押出し性に問題がある。
【００１８】
［Ｚｎ量］
Ｚｎ量は、添加量が多いほど、耐食性を改善する効果があり、耐食性の点で０．５重量％以上添加する必要がある。１．５重量％を超えると、晶出物を生成し、脆化するため、押出し性の点で問題がある。
【００１９】
［Ｍｎ量］
Ｍｎは、添加量が多いほど、耐食性、加工性を改善する効果があり、０．０５重量％以上添加する必要がある。
【００２０】
［Ｆｅ、Ｓｉ、Ｃｕ、Ｎｂ、Ｃａ量］
押し出し性、加工性の点で、有害な成分であり、極力少ないほうが望ましい。不可避に含まれる含有量については、Ｆｅは０．３重量％以下、Ｓｉは０．１重量％未満、Ｃｕは０．１重量％未満、Ｎｂは０．００５重量％未満が望ましい。
【００２１】
マグネシウム合金板の厚みは特に限定されるものではないが、特に０．２〜１．５ｍｍの範囲が望ましい。
【００２２】
上記組成を有するマグネシウム合金板は、Ｘ線回折でのＸ線強度比［（０００２）面のＸ線強度］／［（１０１（上バー）１）面のＸ線強度］が１．０〜３．５であることが望ましい。上記範囲とすることにより、室温から２００℃位の温度範囲における加工性が優れる。軽度の加工であれば、室温での成形が可能であり、また従来２５０℃程度以上の加熱が必要とされた強加工に関しても、２００℃程度の加熱で加工が実施可能となる。
【００２３】
次に、前記マグネシウム合金板に被覆する易剥離性を有する樹脂フィルムは、ポリエステル樹脂、ポリ４フッ化エチレン樹脂、ポリエチレン樹脂あるいはポリエチレン樹脂とポリプロピレン樹脂の２層からなる樹脂であることが望ましい。この樹脂フィルムは、マグネシウム合金板の加工性向上、ならびに加工時のマグネシウム板表面を保護する役割を果たす。また、加工時、剥離することにより放熱性、導電性の優れた表面が得られる。下地との接着強度は、Ｔピール強度で、０．５ｋｇ／板幅ｃｍ以下であることが重要である。０．５ｋｇ／板幅ｃｍを超えると、この板を加工した後、このフィルムの下地にこのフィルムが残存することがあり、製品としての意匠性等の見映え上好ましくない。
【００２４】
このような接着強度とするために、易剥離性のフィルムの被覆条件は適宜選べばよい。
【００２５】
また、前記樹脂被覆マグネシウム合金板は、易剥離性の樹脂フィルムを被覆層の下に、意匠性を有する印刷された樹脂フィルムを被覆しても良い。この意匠性を有するフィルムは、特に限定されるものではなく、透明あるいは印刷層を有する熱可塑性の樹脂フィルムであれば良い。例えば、ポリエステル樹脂、ポリ４フッ化エチレン樹脂、ポリエチレン樹脂あるいはポリエチレン樹脂とポリプロピレン樹脂の２層からなる樹脂であることが望ましい。樹脂フィルムのマグネシウム合金板に対する被覆方法は、公知の方法、すなわち、アクリル系、合成ゴム系あるいはエポキシ系などの接着剤を介して接着する方法が適用できる。印刷する方法は、公知の方法で良く、例えば、グラビア印刷等が適用できる。
【００２６】
このように作成した樹脂被覆マグネシウム合金板を利用して携帯機器筐体等の成型品を成形する場合には、まず必要に応じて樹脂被覆マグネシウム合金板を常温〜被覆してある樹脂フィルムの融点未満に加熱し、続いて深絞りなどの成形加工を施した後、易剥離性の樹脂フィルムを剥離して製品とする。製品は、加工後の潤滑油を除くための脱脂を簡略化でき、樹脂被覆により加工疵を低減でき、外観（意匠性も含む）に優れたものとなる。
【００２７】
【実施例】
本発明について、さらに、以下の実施例を参照して具体的に説明する。
【００２８】
（実施例１）
Ｍｇ−３．０重量％Ａｌ−０．９重量％Ｚｎ−０．０６重量％Ｍｎ−０．２重量％Ｆｅの組成を有する、板厚０．３ｍｍのマグネシウム合金板に、易剥離性を有し、下層が合成ゴム、上層がポリエステル樹脂からなる２層フィルムを両面に被覆した。
【００２９】
（実施例２）
Ｍｇ−３．０重量％Ａｌ−０．９重量％Ｚｎ−０．０６重量％Ｍｎ−０．２重量％Ｆｅの組成を有する、板厚０．３ｍｍのマグネシウム合金板に、外面側として使われる面のみに印刷層を有するポリエステル樹脂を被覆し、更に、易剥離性を有するポリ４フッ化エチレン樹脂フィルムを両面に被覆した。
（比較例１）
実施例１のＭｇ−３．０重量％Ａｌ−０．９重量％Ｚｎ−０．０６重量％Ｍｎ−０．２重量％Ｆｅの組成を有する、板厚０．３ｍｍのマグネシウム合金板を作成した。
【００３０】
上記のように、作製した樹脂被覆マグネシウム合金板の特性を評価した。評価結果を表１に示す。評価方法は下記に示す通り。
【００３１】
［Ｘ線強度比の評価］
管球としてＣｕを用い、電圧５０ｋＶ、電流１９０ｍＡの条件で、Ｘ線強度を測定し、Ｘ線強度比［（０００２）面のＸ線強度］／［（１０１（上バー）１）面のＸ線強度］を求めた。
【００３２】
［深絞り加工性の評価］
携帯機器筐体を成型品として成形する場合において、絞り比を１．４、１．７、２．０の３条件とし、加工時の常温〜被覆してある樹脂フィルムの融点未満の温度として５０℃、１５０℃、２００℃とし、潤滑油などの加工油を使用せず、深絞り加工を行った。深絞り加工が行える場合を○で表し、加工時破断した場合を×として表した。表１の各絞り比での評価では、一番左は加工時の温度が５０℃、真中が１５０℃、一番右が２００℃での結果を示す。
【００３３】
［易剥離性樹脂フィルムの接着強度の評価］
幅１ｃｍ、長さ５ｃｍにサンプルを切断し、Ｔピール強度試験により、易剥離性樹脂フィルムとその下地との接着強度を測定した。
【００３４】
［加工後の外観］
加工時の温度が２００℃で、絞り比１．７で深絞り加工した後、易剥離性樹脂フィルムを剥離し、外観を肉眼で観察した。易剥離性樹脂フィルムを被覆しない場合においては、深絞り加工後に外観を肉眼で評価した。加工疵がなく、易剥離性樹脂フィルムの残存が認められない場合を良好とし、○で表した。一方、加工疵あるいは易剥離性樹脂フィルムの残存がある場合を不良とし、×で表した。
【００３５】
評価結果を表１に示す。表１に示すように、本発明の易剥離性樹脂フィルムを被覆したマグネシウム合金板は、比較例１の易剥離性樹脂フィルムを被覆しないマグネシウム合金板と比べて、深絞り加工性が優れたものとなる。
【００３６】
【表１】

【００３７】
【発明の効果】
本発明はこのように構成され作用するものであるために、加工性、特に室温から準温間域における深絞り加工性などのプレス成形性に優れ、加工後の脱脂を簡略化でき、かつ、経済性の点でも優れた樹脂被覆マグネシウム合金板、樹脂被覆マグネシウム合金板から成形する成形体の製造方法および携帯機器筐体を得ることができる。
【００３８】
具体的には、本発明の樹脂被覆マグネシウム合金板は、その素材となるマグネシウム合金板の組成がＡｌを１．５〜５．５重量％、Ｚｎを０．５〜１．５重量％、Ｍｎを０．０５重量％以上、Ｆｅを０．３重量％以下含有し、残部がＭｇ及び不可避の不純物からなり、望ましくはＸ線回折でのＸ線強度比［（０００２）面のＸ線強度］／［（１０１（上バー）１）面のＸ線強度］が１．０〜３．５であり、その素材の表面に易剥離性樹脂フィルムを被覆したものからなり、深絞り性に優れ、加工後の加工油除去する脱脂を簡略化でき、かつ携帯機器筐体などの製品に加工した後でも、外観（意匠性含む）が優れたものとなる等の効果を有する。
【００３９】
また、本発明の樹脂被覆マグネシウム合金板から成形する成形体の製造方法は、前記構成を備えたマグネシウム合金板の少なくとも片面に易剥離性を有する樹脂フィルムを被覆し、常温〜該樹脂フィルムの融点未満に加熱し、成形加工後、該樹脂フィルムを剥離するものであるために、携帯機器筐体などの成形品を成形する場合において、深絞り性に優れ、加工後の加工油除去する脱脂を簡略化でき、全体としてコストも低廉なものとなり、成型品の加工後の外観（意匠性含む）の優れたものとなる等の効果を奏する。
【００４０】
従って、本発明の携帯機器筐体は、前記構成を備えた樹脂被覆マグネシウム合金板を素材としており、また、前記の通りの製造方法によって製造されるものであるために、深絞り性に優れ、加工後の加工油除去する脱脂を簡略化でき、全体としてコストも低廉なものとなり、加工後の外観（意匠性含む）も優れたものとなる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inexpensive resin-coated magnesium alloy sheet having excellent moldability, particularly excellent press moldability in a sub-warm range from room temperature to about 200 ° C., a method for producing a molded article molded from the resin-coated magnesium alloy sheet, and a portable device. Related to the housing.
[0002]
[Prior art]
Conventionally, a magnesium alloy sheet is made into a thin sheet by repeatedly heat-treating, hot-rolling, and warm-rolling a cast slab having a thickness of several mm to several tens of mm or a thick sheet by extrusion. Such a thin magnesium alloy sheet produced by repeatedly performing heat treatment, hot rolling, warm rolling, etc., is inferior in workability at a temperature in a range from room temperature to a quasi-warm temperature, that is, cold, and is economical. Therefore, it is expensive and has not been widely used.
[0003]
In recent years, since magnesium alloys have a lower specific gravity, higher non-rigidity, and can be made lighter than Al, there is an increasing demand for magnesium alloy plates that are inexpensive and have excellent formability. Then, as a magnesium alloy excellent in press formability, a composition and rolling conditions for improving press formability have been proposed (for example, see Patent Document 1). It is also proposed to improve the ductility and bending workability in cold by adding lithium to magnesium to generate one part of β phase of bcc structure in α phase of hcp structure or to make β single phase. However, since lithium is an active metal, there is a problem not only in safety in handling industrially in large quantities, but also in that it is expensive and significantly reduces the corrosion resistance of magnesium. There is.
[0004]
Further, there is a proposal for hot working of magnesium, but a study of a working method and conditions for imparting large strain for the purpose of crystal grain refinement is disclosed, and the crystal grain size is reduced to 1 μm or less. Although it is miniaturized, there is no mention of improvement in moldability (for example, see Patent Document 4). Further, the shape is limited or hot forging needs to be repeatedly performed, so that a thin magnesium alloy sheet cannot be produced.
[0005]
Processing using a lubricating oil requires a special lubricating oil and also requires subsequent degreasing. In addition, in ordinary degreasing, it is difficult to remove the lubricating oil, which involves many problems.
[0006]
Prior art document information on the present application includes the following.
[0007]
[Patent Document 1]
JP-A-6-293944 [Patent Document 2]
JP-A-6-25788 [Patent Document 3]
JP-A-9-41066 [Patent Document 4]
Japanese Patent Application Laid-Open No. 2000-271693
[Problems to be solved by the invention]
The present invention has been made in view of these points, and is excellent in workability, particularly in press formability such as deep drawing workability in a range from room temperature to a quasi-warm temperature, can simplify degreasing after processing, and is economical. It is an object of the present invention to provide a resin-coated magnesium alloy plate which is inexpensive in terms of properties, a method of manufacturing a molded article formed from the resin-coated magnesium alloy plate, and a portable device housing.
[0009]
[Means for Solving the Problems]
Then, the present inventor has made intensive studies and found that the following resin-coated magnesium alloy is excellent in workability and can simplify subsequent degreasing.
[0010]
The resin-coated magnesium alloy plate according to the first aspect is characterized in that at least one surface of the magnesium alloy plate is coated with a resin film having easy peelability. The magnesium alloy plate contains 1.5 to 5.5% by weight of Al, 0.5 to 1.5% by weight of Zn, 0.05% by weight or more of Mn, and 0.3% by weight or less of Fe, The balance is desirably made of Mg and unavoidable impurities. Further, the magnesium alloy plate has an X-ray intensity ratio [X-ray intensity of (0002) plane] / [X-ray intensity of (101 (upper bar) 1) plane] in X-ray diffraction of 1.0 to 3.0. 5 is desirable.
[0011]
On the other hand, it is preferable that the resin film having the easy peeling property is a polyester resin, a polytetrafluoroethylene resin, a polyethylene resin, or a resin having two layers of a polyethylene resin and a polypropylene resin. In this case, it is desirable that the resin film having the easy peeling property has an adhesive strength to the magnesium alloy plate of 0.5 kg / cm or less in T peel strength.
[0012]
A method for producing a molded article molded from the resin-coated magnesium alloy sheet according to claim 6, wherein at least one surface of the magnesium alloy sheet is coated with a resin film having easy releasability, and is heated from room temperature to a temperature lower than the melting point of the resin film; After the forming process, the resin film is peeled off. In this case, the magnesium alloy sheet contains 1.5 to 5.5% by weight of Al, 0.5 to 1.5% by weight of Zn, 0.05% by weight or more of Mn, and 0.3% by weight or less of Fe. Desirably, the balance is made of Mg and unavoidable impurities. Further, the magnesium alloy plate has an X-ray intensity ratio [X-ray intensity of (0002) plane] / [X-ray intensity of (101 (upper bar) 1) plane] in X-ray diffraction of 1.0 to 3.0. 5 is desirable.
[0013]
On the other hand, it is preferable that the resin film having the easy peeling property is a polyester resin, a polytetrafluoroethylene resin, a polyethylene resin, or a resin having two layers of a polyethylene resin and a polypropylene resin. Further, it is desirable that the resin film having the easy peeling property has an adhesive strength to a magnesium alloy plate of 0.5 kg / cm or less in T peel strength.
[0014]
An eleventh aspect of the present invention provides a portable device housing formed using the resin-coated magnesium alloy plate according to any one of the first to fifth aspects.
[0015]
According to a twelfth aspect of the present invention, a mobile device housing is formed by using the method for manufacturing a molded body formed from the resin-coated magnesium alloy plate according to any one of the sixth to tenth aspects. I do.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
The above-mentioned magnesium alloy plate contains 2.0 to 5.0% by weight of Al, 0.5 to 2.0% by weight of Zn, 0.05% by weight or more of Mn, and 0.3% by weight or less of Fe. The remainder has a component consisting of Mg and unavoidable impurities, the surface of which is coated with a resin film having an easy peeling property, and has excellent workability, particularly excellent press moldability between room temperature and quasi-temperature. It can be simplified and economical. The appropriate concentration range of each component is as follows.
[0017]
[Al content]
As the amount of Al increases, the effect of improving the strength increases as the amount of Al increases, and it is necessary to add 1.5% by weight or more in terms of strength. If the content exceeds 5.5% by weight, the crystallized product does not form a solution but becomes brittle, and there is a problem in extrudability.
[0018]
[Zn content]
As the amount of Zn increases, the effect of improving the corrosion resistance increases as the amount of Zn added, and it is necessary to add 0.5% by weight or more in terms of corrosion resistance. If the content exceeds 1.5% by weight, a crystallized product is formed and the material becomes brittle, so that there is a problem in terms of extrudability.
[0019]
[Mn amount]
Mn has an effect of improving corrosion resistance and workability as the added amount is larger, and it is necessary to add 0.05% by weight or more.
[0020]
[Fe, Si, Cu, Nb, Ca amounts]
It is a harmful component in terms of extrudability and processability, and it is desirable that the content be as small as possible. Regarding the contents unavoidably contained, it is desirable that Fe is 0.3% by weight or less, Si is less than 0.1% by weight, Cu is less than 0.1% by weight, and Nb is less than 0.005% by weight.
[0021]
The thickness of the magnesium alloy plate is not particularly limited, but is preferably in the range of 0.2 to 1.5 mm.
[0022]
The magnesium alloy sheet having the above composition has an X-ray intensity ratio of X-ray diffraction [X-ray intensity of (0002) plane] / [X-ray intensity of (101 (upper bar) 1) plane] of 1.0 to 3 in X-ray diffraction. .5. By setting it in the above range, workability in a temperature range from room temperature to about 200 ° C. is excellent. If the processing is mild, molding can be performed at room temperature, and the processing can be performed by heating at about 200 ° C. even for the strong processing that conventionally required heating at about 250 ° C. or more.
[0023]
Next, the easily peelable resin film that covers the magnesium alloy plate is desirably a polyester resin, a polytetrafluoroethylene resin, a polyethylene resin, or a resin composed of two layers of a polyethylene resin and a polypropylene resin. This resin film plays a role in improving the workability of the magnesium alloy plate and protecting the surface of the magnesium plate during processing. In addition, a surface excellent in heat dissipation and conductivity can be obtained by peeling during processing. It is important that the adhesive strength to the base be T-peel strength of 0.5 kg / plate width cm or less. If it exceeds 0.5 kg / plate width cm, this film may remain on the base of this film after processing this plate, which is not preferable in terms of appearance such as design properties as a product.
[0024]
In order to obtain such adhesive strength, the condition for coating the easily peelable film may be appropriately selected.
[0025]
In addition, the resin-coated magnesium alloy plate may be covered with a printed resin film having a design property under the coating layer of the easily peelable resin film. The film having this design property is not particularly limited, and may be a transparent or thermoplastic resin film having a print layer. For example, a resin composed of a polyester resin, a polytetrafluoroethylene resin, a polyethylene resin, or a resin having two layers of a polyethylene resin and a polypropylene resin is desirable. As a method of coating the magnesium alloy plate with the resin film, a known method, that is, a method of bonding with an adhesive such as acrylic, synthetic rubber, or epoxy can be applied. A printing method may be a known method, and for example, gravure printing or the like can be applied.
[0026]
When molding a molded article such as a housing of a portable device using the resin-coated magnesium alloy plate thus prepared, first, the melting point of the resin film coated with the resin-coated magnesium alloy plate from room temperature to room temperature as necessary. After heating to less than 1% and then performing a forming process such as deep drawing, the easily peelable resin film is peeled off to obtain a product. The product can be easily degreased to remove lubricating oil after processing, can reduce processing flaws by resin coating, and has excellent appearance (including design).
[0027]
【Example】
The present invention will be further specifically described with reference to the following examples.
[0028]
(Example 1)
A magnesium alloy sheet having a composition of Mg-3.0% by weight Al-0.9% by weight Zn-0.06% by weight Mn-0.2% by weight Fe and having a thickness of 0.3 mm has easy peelability. Then, both surfaces were coated with a two-layer film in which the lower layer was made of synthetic rubber and the upper layer was made of polyester resin.
[0029]
(Example 2)
Mg-3.0% by weight Al-0.9% by weight Zn-0.06% by weight Mn-0.2% by weight Fe is used as an outer surface side on a 0.3 mm thick magnesium alloy sheet having a composition of Fe. A polyester resin having a printed layer only on one side was coated, and a polytetrafluoroethylene resin film having easy peelability was coated on both sides.
(Comparative Example 1)
A 0.3 mm thick magnesium alloy sheet having a composition of Mg-3.0 wt% Al-0.9 wt% Zn-0.06 wt% Mn-0.2 wt% Fe of Example 1 was prepared. .
[0030]
As described above, the characteristics of the produced resin-coated magnesium alloy sheet were evaluated. Table 1 shows the evaluation results. The evaluation method is as shown below.
[0031]
[Evaluation of X-ray intensity ratio]
X-ray intensity was measured using Cu as the bulb under the conditions of a voltage of 50 kV and a current of 190 mA, and the X-ray intensity ratio [X-ray intensity of (0002) plane] / [X of (101 (upper bar) 1) plane) was measured. Linear intensity].
[0032]
[Evaluation of deep drawing workability]
When the housing of the portable device is molded as a molded product, the drawing ratio is set to three conditions of 1.4, 1.7, and 2.0. C., 150.degree. C., and 200.degree. C., and deep drawing was performed without using a processing oil such as a lubricating oil. The case where deep drawing could be performed was represented by 、, and the case where it was broken during processing was represented by x. In the evaluation at each drawing ratio in Table 1, the leftmost results are at a processing temperature of 50 ° C, the middle is 150 ° C, and the rightmost is the result at 200 ° C.
[0033]
[Evaluation of adhesive strength of easily peelable resin film]
The sample was cut into a width of 1 cm and a length of 5 cm, and the adhesive strength between the easily peelable resin film and its base was measured by a T-peel strength test.
[0034]
[Appearance after processing]
After deep-drawing at a processing temperature of 200 ° C. and a drawing ratio of 1.7, the easily peelable resin film was peeled off, and the appearance was visually observed. When not coated with the easily peelable resin film, the appearance was visually evaluated after deep drawing. A case where there was no processing flaw and no residue of the easily peelable resin film was observed was regarded as good, and was represented by ○. On the other hand, the case where there was a processing flaw or the residue of the easily peelable resin film was regarded as defective, and represented by x.
[0035]
Table 1 shows the evaluation results. As shown in Table 1, the magnesium alloy plate coated with the easily peelable resin film of the present invention was superior in the deep drawability to the magnesium alloy plate not coated with the easily peelable resin film of Comparative Example 1. It becomes.
[0036]
[Table 1]

[0037]
【The invention's effect】
Since the present invention is configured and operated in this manner, it is excellent in workability, particularly in press formability such as deep drawing workability in a temperature range from room temperature to a quasi-warm range, and can simplify degreasing after processing, and It is possible to obtain a resin-coated magnesium alloy plate, a method for manufacturing a molded article molded from the resin-coated magnesium alloy plate, and a housing for a portable device which are also excellent in economical efficiency.
[0038]
Specifically, in the resin-coated magnesium alloy sheet of the present invention, the composition of the magnesium alloy sheet as the material is such that Al is 1.5 to 5.5% by weight, Zn is 0.5 to 1.5% by weight, and Mn is Mn. , 0.05% by weight or less of Fe, and 0.3% by weight or less of Fe, and the balance consists of Mg and unavoidable impurities. Desirable X-ray intensity ratio in X-ray diffraction [X-ray intensity of (0002) plane] / [(X-ray intensity of (101 (upper bar) 1) plane)] is 1.0 to 3.5, and is made of a material whose surface is coated with an easily peelable resin film, and has excellent deep drawability. Degreasing for removing processing oil after processing can be simplified, and even after processing into a product such as a mobile device housing, the appearance (including design) is improved.
[0039]
Further, the method for producing a molded article formed from the resin-coated magnesium alloy sheet of the present invention comprises coating at least one surface of the magnesium alloy sheet having the above-mentioned structure with a resin film having easy peelability, and at room temperature to the melting point of the resin film. Since the resin film is peeled off after being heated to less than the forming process, when molding a molded article such as a portable device housing, it is excellent in deep drawability, and has a degreasing property for removing processing oil after processing. Simplification can be achieved, the overall cost can be reduced, and the appearance (including the design) of the molded product after processing can be improved.
[0040]
Therefore, the mobile device housing of the present invention is made of a resin-coated magnesium alloy plate having the above-described configuration, and is manufactured by the manufacturing method as described above. Degreasing for removing the processing oil after processing can be simplified, the cost as a whole becomes low, and the appearance (including design) after processing becomes excellent.

Claims

A resin-coated magnesium alloy plate, wherein at least one surface of the magnesium alloy plate is coated with a resin film having easy peelability.

The magnesium alloy plate contains 1.5 to 5.5% by weight of Al, 0.5 to 1.5% by weight of Zn, 0.05% by weight or more of Mn, and 0.3% by weight or less of Fe, The resin-coated magnesium alloy plate according to claim 1, wherein the balance is made of Mg and unavoidable impurities.

The magnesium alloy plate has an X-ray intensity ratio [X-ray intensity of (0002) plane] / [X-ray intensity of (101 (upper bar) 1) plane] in X-ray diffraction of 1.0 to 3.5. The resin-coated magnesium alloy plate according to claim 1 or 2, wherein:

4. The resin film having easy releasability, wherein the resin film is a polyester resin, a polytetrafluoroethylene resin, a polyethylene resin, or a resin composed of two layers of a polyethylene resin and a polypropylene resin. 2. The resin-coated magnesium alloy sheet according to claim 1.

5. The resin film according to claim 1, wherein the easily peelable resin film has an adhesive strength to a magnesium alloy plate of 0.5 kg / cm or less in T peel strength. 6. Resin coated magnesium alloy plate.

A resin-coated magnesium alloy plate, characterized in that at least one surface of a magnesium alloy plate is coated with a resin film having an easy peeling property, the resin film is heated at a temperature from room temperature to less than the melting point of the resin film, and the resin film is peeled off after forming. A method for producing a molded article to be molded from.

The magnesium alloy plate contains 1.5 to 5.5% by weight of Al, 0.5 to 1.5% by weight of Zn, 0.05% by weight or more of Mn, and 0.3% by weight or less of Fe, The method according to claim 6, wherein the balance comprises Mg and unavoidable impurities.

The magnesium alloy plate has an X-ray intensity ratio [X-ray intensity of (0002) plane] / [X-ray intensity of (101 (upper bar) 1) plane] in X-ray diffraction of 1.0 to 3.5. A method for producing a molded article formed from the resin-coated magnesium alloy sheet according to claim 6.

9. The resin film having easy releasability, comprising a polyester resin, a polytetrafluoroethylene resin, a polyethylene resin, or a resin having two layers of a polyethylene resin and a polypropylene resin. A method for producing a molded article formed from the resin-coated magnesium alloy sheet according to claim 1.

10. The resin film according to claim 6, wherein the easily peelable resin film has an adhesive strength to a magnesium alloy plate of 0.5 kg / cm or less in T peel strength. A method for producing a molded article formed from a resin-coated magnesium alloy sheet.

A portable device housing formed using the resin-coated magnesium alloy plate according to claim 1.

A portable device housing formed by using the method for manufacturing a molded product formed from the resin-coated magnesium alloy plate according to claim 6.