JP3563931B2 - Rubber mold - Google Patents
Rubber mold Download PDFInfo
- Publication number
- JP3563931B2 JP3563931B2 JP22794997A JP22794997A JP3563931B2 JP 3563931 B2 JP3563931 B2 JP 3563931B2 JP 22794997 A JP22794997 A JP 22794997A JP 22794997 A JP22794997 A JP 22794997A JP 3563931 B2 JP3563931 B2 JP 3563931B2
- Authority
- JP
- Japan
- Prior art keywords
- mold
- rubber
- alloy
- film
- phase
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Description
【0001】
【発明の属する技術分野】
本発明は、天然ゴムや合成ゴム等の成形に用いられる耐食性、離型性に優れたゴム成形用金型に関するものである。
【0002】
【従来の技術】
天然ゴムや合成ゴムなど各種ゴム類は、自動車の部品であるホース類、シール材、動力用ベルト、タイヤをはじめあらゆる産業分野で広く使われている。ゴム部品を成形する金型材料としては、S45C、SCr、SCM、SNCMなどの機械構造用合金鋼やSUS304などのステンレス鋼が使用されているが、ゴム成形過程で金型が汚染されて離型性が悪くなる。このため、一定成形回数毎に金型内面に付着した薬剤や重合物中の非ゴム成分等の付着堆積物を、溶剤洗浄あるいは機械的に除去したりする煩雑な方法を行っている。
【0003】
従来、ゴム成分の汚染および堆積を防止し、離型性を確保する方法として、金型表面にCrメッキを施したり、Ni合金皮膜(例えばNi−P、Ni−Sn等)をコーティングしたり、あるいは成形工程でフッ素系の離型剤を金型面内に塗布するなどの工夫が行われている。
【0004】
【発明が解決しようとする課題】
しかしながら、Crメッキ法はメッキ層に内在する微細な欠陥から金型の腐食が生じたり、メッキ層が剥離脱落しやすく、この方法では耐久性が充分とは言えない。
【0005】
またNi系のコーティングは、通常ではイオンプレーティング法によって2〜3層に成膜させるため、コストの上昇を招くと共にコーティング層の剥離を回避するために数μm以下の層厚にする必要があり、これもまた耐久性に問題があった。特に、エチレン・プロピレン・ジエン・メチレンゴム(EPDM)を成形する場合、耐食性、離型性等の面で十分な性能が得られない。耐食性が低いと、腐食による錆やかすが発生し、また配合薬品、重合体中の非ゴム成分などの堆積による汚染が原因となって離型性が悪くなる。これらはゴム成品の善し悪しおよび生産性に直接影響を与える因子であるので、その解決が強く望まれている。
【0006】
また離型剤の塗布については、適用しうるゴムの種類が限られたり、たとえ塗布による効果があっても、手間がかかって生産性が低下したり、不良率の増大などの問題がある。
【0007】
【課題を解決するための手段】
本発明者らはこうした状況に鑑み、ゴム成形用金型は金型材料の合金組成から耐食性、離型性を改良しなければならないと考え、種々検討した。その結果、表面にアルミナ皮膜を形成した金型がゴム成形に対する耐食性、離型性の点で優れていることを見い出した。本発明は、上記の知見に基づいてなされたものである。
【0008】
金型表面にアルミナ皮膜を形成させるには、従来の金型材料、すなわち機械構造用鋼であるS45Cなどを切削加工した後にPVD法などに依っても可能である。しかし、これらの方法ではコスト面から引き合わないことと、母材と皮膜との密着性が低く、使用途中に皮膜が剥離してしまうなどの問題が生じる。
【0009】
本発明は、ゴム成形用金型においてゴムが接触する部分に強固なアルミナ皮膜を有し、かつそのアルミナ皮膜が合金成分中のAlの拡散による自生した皮膜であることを特徴としたゴム成形用金型である。すなわち、ゴム成形用金型としての要件である、高強度、良切削性、高熱伝導度などの特性を具備した合金であり、さらにその合金金型表面が酸化加熱処理を行うことによりアルミナ皮膜に覆われ、その皮膜によって耐食性、離型性、耐磨耗性を持った金型を提供するものである。
【0010】
本発明者らの検討に依れば、ゴム成形用金型として最も目的にかなった特性を発揮する合金成分は、以下の通りである。
すなわち、重量比で、Cu:20〜60%、Al:2〜12%、Cr:4〜11%、Ni:2〜24%、Mo:0.2〜1.8%、残部Feおよび不可避的不純物元素からなる合金であり、選択的に希土類元素:0.01〜0.1%を含有する金型である。
【0011】
次に、本発明の金型用合金成分の役割と組成範囲の限定について詳細に説明する。
Al:アルミニウムは、金型表面にアルミナ皮膜を自生させ、ゴム成分の金型付着を防止し、離型性を発揮させるための重要な元素である。含有量が3重量%未満では皮膜形成が不安定であり、12重量%以上になるとCu相中にβ相が出現し、脆化が激しくなるために3〜12重量%とした。
【0012】
Cu:Cuは、Feと合金化しない元素であることを利用してCu相を出現させることによりFe相を分断し、Al添加鋼の切削性を改善した。また、Cuは、Fe相中にも微細なCu相を出現させてアルミナ皮膜生成を促進させる元素である。含有量が20重量%未満では切削性が悪くなり、60重量%以上では金型としての硬度が不足する。このため、適正範囲を20〜60重量%とした。
Cr:Crは、Fe相のみに固溶してFe相の耐食性向上のために役立つ元素である。含有量が4〜11重量%でこの効果を発揮するので適正範囲を4〜11重量%とした。
【0013】
Ni:NiはFeおよびCu相にも固溶し、Fe相の耐食性を向上させるとともにCu相の硬度改善に寄与する元素である。含有量2〜24重量%でこれらの効果を最大限発揮する。
【0014】
Mo:Moは、Fe相に固溶し、耐孔食性を向上させる元素であり、0.2〜1.8%が適正範囲である。
以上に述べた元素を組成とする金型を用いることにより耐汚染性は達成することが可能であるが、さらに以下の元素を加えることにより各種特性を向上させることが出来る。
希土類元素:酸化処理により自生したアルミナ皮膜と母材との密着をより強固にする元素であり、0.01%未満ではその効果が薄く0.1%以上では効果が飽和する。
以上説明したこれら元素の組成配合は、ゴム製品の成形目的に応じて決定する。
【0015】
本発明金型用合金の製造は、高周波溶解炉等で成分調整を行って溶製し、容易にインゴットを作成することが出来る。
【0016】
本発明の合金金型におけるアルミナ皮膜生成処理は、酸化雰囲気中で金型を加熱することにより得られる。すなわち、本発明の金型用合金を金型の形状に切削加工を施した後、電気炉等により大気中において800〜950℃の温度で1時間以上、好ましくは4時間程度加熱することにより金型表面に厚さ1μm以下で密着性の高い強固な皮膜が生成される。
【0017】
このように金型表面にアルミナ皮膜を形成した本発明合金金型は、従来金型に較べて耐汚染性に優れており、洗浄工程間隔を著しく延ばすことが出来る。また本合金金型を長期間使用し汚染物質が付着した場合、従来の付着物除去法であるアルカリ溶液への浸漬工程を経てもアルミナ皮膜は全く損傷を受けない。また物理的な原因でアルミナ皮膜を損傷することがあっても、再度皮膜生成処理を行えば損傷箇所に皮膜が再生され、容易に効果を回復させることが出来るなど、メンテナンスの上からも優れた金型である。
【0018】
【実施例】
表1に示す組成の合金を100kg高周波溶解炉にて溶製してインゴットを作成した。次いで、自動車のフロント、リヤーなどのウインドウシール用ゴム製品を作るためのウエザーストリップ成形用金型を切削加工により作製した。金型表面へのアルミナ皮膜生成処理は、電気炉を用いて、酸化雰囲気中で920℃の温度で4時間保定後、炉中で室温まで冷却した。比較材としてはS45Cを用い、切削加工後、厚さ3μmの工業用クロムメッキを金型表面に施し、比較材の金型を得た。
【0019】
【表1】
【0020】
金型材料の切削性の評価は、縦型フライス盤にて切削深さ3mmで平面切削を行ったときに、バイトに無理が掛らない最大移動速度の大小から評価した。その結果を、表2に示した。
表2において、◎は最大移動速度が大、○は中、△は小であることを示す。
【0021】
離型性の評価は、EPDM、および天然ゴムを用い、ウエザーストリップを金型成形し、汚染物の付着が認められるまでの連続回数を測定した。測定試験は5個のサンプルについて行い、その平均した値を、表2に示す。
【0022】
表2から明らかなように、本発明金型用合金の切削性はS45Cに較べて良好で、耐汚染性はEPDM、天然ゴムともCrメッキの従来金型に較べて4〜5倍も優れている。
【0023】
【表2】
【0024】
【発明の効果】
本発明のゴム成形用金型は、材料の切削性に優れ、かつ耐汚染性が従来の金型に較べて大幅に向上し、生産性はもとより不良率も大幅に改善され、ゴム成形分野に大きく貢献するものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rubber molding die having excellent corrosion resistance and releasability used for molding natural rubber, synthetic rubber, and the like.
[0002]
[Prior art]
Various rubbers such as natural rubber and synthetic rubber are widely used in various industrial fields including hoses, sealing materials, power belts, and tires, which are automobile parts. As a mold material for molding rubber parts, alloy steel for mechanical structure such as S45C, SCr, SCM, SNCM and stainless steel such as SUS304 are used, but the mold is contaminated during the rubber molding process and the mold is released. It becomes worse. For this reason, a complicated method of washing or mechanically removing deposits such as non-rubber components in the polymer and chemicals adhered to the inner surface of the mold every certain number of moldings is performed.
[0003]
Conventionally, as a method for preventing the contamination and accumulation of rubber components and ensuring releasability, a die surface is subjected to Cr plating, a Ni alloy film (for example, Ni-P, Ni-Sn, etc.) is coated, Alternatively, some measures have been taken, such as applying a fluorine-based release agent in the mold surface in the molding step.
[0004]
[Problems to be solved by the invention]
However, the Cr plating method causes corrosion of the mold due to minute defects existing in the plating layer, and the plating layer is easily peeled off, so that this method cannot be said to have sufficient durability.
[0005]
In addition, since the Ni-based coating is usually formed into two or three layers by an ion plating method, it is necessary to reduce the thickness to several μm or less in order to increase the cost and to avoid peeling of the coating layer. This also had a problem with durability. In particular, when molding ethylene / propylene / diene / methylene rubber (EPDM), sufficient performance cannot be obtained in terms of corrosion resistance, releasability, and the like. If the corrosion resistance is low, rust and scum are generated due to corrosion, and the releasability is deteriorated due to contamination due to accumulation of compounding chemicals and non-rubber components in the polymer. Since these are factors that directly affect the quality and productivity of rubber products, their solutions are strongly desired.
[0006]
In addition, the application of the release agent has a problem that the kind of rubber that can be applied is limited, and even if the application is effective, it takes time and effort to lower the productivity and increase the defective rate.
[0007]
[Means for Solving the Problems]
In view of such circumstances, the present inventors have considered variously that a rubber mold has to improve corrosion resistance and mold releasability from the alloy composition of the mold material. As a result, it was found that a mold having an alumina film formed on the surface was excellent in terms of corrosion resistance against rubber molding and mold release properties. The present invention has been made based on the above findings.
[0008]
In order to form an alumina film on the surface of the mold, a conventional mold material, that is, S45C or the like for machine structural use, may be cut, and then the PVD method may be used. However, these methods have problems in that they cannot be obtained from the viewpoint of cost, that the adhesion between the base material and the film is low, and that the film peels off during use.
[0009]
The present invention relates to a rubber molding die, characterized in that a rubber molding die has a strong alumina film at a portion where rubber comes into contact, and the alumina film is a film spontaneously formed by diffusion of Al in an alloy component. It is a mold. In other words, it is an alloy having characteristics such as high strength, good machinability, and high thermal conductivity, which are the requirements for a rubber molding die. It is intended to provide a mold which is covered and has corrosion resistance, release property and abrasion resistance by its film.
[0010]
According to the study of the present inventors, the following alloy components exhibit the most desired characteristics as a rubber molding die.
That is, by weight ratio, Cu: 20 to 60%, Al: 2 to 12%, Cr: 4 to 11%, Ni: 2 to 24%, Mo: 0.2 to 1.8%, balance Fe and inevitable an alloy consisting of impurity elements, selectively rare earth elements: a die containing 0.01% to 0.1%.
[0011]
Next, the role of the alloy component for a mold of the present invention and the limitation of the composition range will be described in detail.
Al: Aluminum is an important element for forming an alumina film on the surface of the mold, preventing adhesion of the rubber component to the mold, and exhibiting releasability. When the content is less than 3% by weight, the film formation is unstable, and when the content is 12% by weight or more, a β phase appears in the Cu phase and embrittlement becomes severe.
[0012]
Cu: Cu is an element that is not alloyed with Fe to make a Cu phase appear, thereby separating the Fe phase and improving the machinability of the Al-added steel. Further, Cu is an element that causes a fine Cu phase to appear in the Fe phase to promote the formation of an alumina film. If the content is less than 20% by weight, the machinability deteriorates, and if it is more than 60% by weight, the hardness as a mold is insufficient. Therefore, the appropriate range is set to 20 to 60% by weight.
Cr: Cr is an element which forms a solid solution only in the Fe phase and is useful for improving the corrosion resistance of the Fe phase. Since the effect is exhibited when the content is 4 to 11% by weight, the appropriate range is set to 4 to 11% by weight.
[0013]
Ni: Ni is also a solid solution in Fe and Cu phase, an element which contributes to the hardness improvement of the Cu phase to be with the improved corrosion resistance of the Fe phase. These effects are maximized when the content is 2 to 24% by weight.
[0014]
Mo: Mo is an element that forms a solid solution in the Fe phase and improves pitting corrosion resistance, and the appropriate range is 0.2 to 1.8%.
Stain resistance can be achieved by using a mold having the composition described above, but various characteristics can be improved by further adding the following elements.
Rare earth element: An element that further strengthens the adhesion between the alumina film spontaneously formed by the oxidation treatment and the base material. When the content is less than 0.01%, the effect is small, and when the content is 0.1% or more, the effect is saturated.
The composition and composition of these elements described above are determined according to the purpose of molding the rubber product.
[0015]
In the production of the alloy for a mold of the present invention, the ingot can be easily prepared by adjusting the components in a high-frequency melting furnace or the like and melting the alloy.
[0016]
The alumina film forming treatment in the alloy mold of the present invention can be obtained by heating the mold in an oxidizing atmosphere. That is, after the mold alloy of the present invention is subjected to cutting in the shape of the mold, the metal is heated at 800 to 950 ° C. for 1 hour or more, preferably about 4 hours in the air by an electric furnace or the like. A strong film having a high adhesion and a thickness of 1 μm or less is formed on the mold surface.
[0017]
The alloy mold of the present invention in which the alumina film is formed on the surface of the mold in this way has excellent stain resistance as compared with the conventional mold, and can significantly increase the cleaning process interval. In addition, when the present alloy mold is used for a long time and a contaminant adheres, the alumina film is not damaged at all even through the immersion step in an alkaline solution which is a conventional method for removing adhered substances. In addition, even if the alumina film may be damaged due to physical causes, the film is regenerated at the damaged part by performing the film generation process again, and the effect can be easily recovered, so it is excellent in terms of maintenance. It is a mold.
[0018]
【Example】
An alloy having the composition shown in Table 1 was melted in a 100 kg high-frequency melting furnace to prepare an ingot. Next, a weatherstrip molding die for producing rubber products for window seals such as automobile fronts and rears was manufactured by cutting. The alumina film formation treatment on the mold surface was performed by using an electric furnace at 920 ° C. for 4 hours in an oxidizing atmosphere, and then cooled to room temperature in the furnace. As a comparative material, S45C was used, and after cutting, industrial chrome plating having a thickness of 3 μm was applied to the surface of the mold to obtain a comparative material mold.
[0019]
[Table 1]
[0020]
The evaluation of the machinability of the mold material was evaluated based on the maximum moving speed at which the cutting tool was not subjected to excessive force when plane cutting was performed at a cutting depth of 3 mm with a vertical milling machine. The results are shown in Table 2.
In Table 2, ◎ indicates that the maximum moving speed is high, ○ indicates medium, and Δ indicates low.
[0021]
The evaluation of the releasability was performed by molding a weatherstrip using EPDM and natural rubber, and measuring the number of continuous times until adhesion of contaminants was recognized. The measurement test was performed on five samples, and the average value is shown in Table 2.
[0022]
As is evident from Table 2, the moldability of the mold of the present invention is better than that of S45C, and the stain resistance of EPDM and natural rubber is 4 to 5 times better than that of the Cr-plated conventional mold. I have.
[0023]
[Table 2]
[0024]
【The invention's effect】
The rubber molding die of the present invention is excellent in the machinability of the material, and the contamination resistance is greatly improved as compared with the conventional die, the productivity as well as the rejection rate are greatly improved, and the rubber molding die is used in the rubber molding field. It is a great contribution.
Claims (2)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP22794997A JP3563931B2 (en) | 1997-08-25 | 1997-08-25 | Rubber mold |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP22794997A JP3563931B2 (en) | 1997-08-25 | 1997-08-25 | Rubber mold |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH1158402A JPH1158402A (en) | 1999-03-02 |
JP3563931B2 true JP3563931B2 (en) | 2004-09-08 |
Family
ID=16868804
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP22794997A Expired - Fee Related JP3563931B2 (en) | 1997-08-25 | 1997-08-25 | Rubber mold |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3563931B2 (en) |
-
1997
- 1997-08-25 JP JP22794997A patent/JP3563931B2/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
JPH1158402A (en) | 1999-03-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
KR101361605B1 (en) | Steel sheet for hot stamping, and process for manufacturing hot-stamped steel products using steel sheet for hot stamping | |
KR20130100340A (en) | Steel sheet for hot pressing and method for producing hot-pressed member using steel sheet for hot pressing | |
KR20120054563A (en) | Method for producing a steel component provided with a metal coating protecting against corrosion and steel component | |
EP0774525B1 (en) | Copper alloy mold for casting aluminium or aluminium alloy | |
US4778540A (en) | Method for surface treatment and treating material therefor | |
KR102031454B1 (en) | Galvinized steel sheet having excellent adhesion at low temperature and excellent workability and method for manufacturing the same | |
EP0056986B2 (en) | Method of preparing a plated shaped product | |
JP3563931B2 (en) | Rubber mold | |
JP2007002333A (en) | Press die with excellent self-lubricating property | |
JP2006219750A (en) | Aluminum alloy for mold and mold for vulcanization obtained by using the same | |
KR20120004811A (en) | Surface treatment method for magnesium alloy | |
US2478171A (en) | Method of making metal drawing dies | |
KR20190076129A (en) | Hot dip aluminium alloy plated steel sheet having excellent corrosion resistance and weldability, method for manufacturing the same | |
JP6593667B1 (en) | Covering member and manufacturing method thereof | |
JPH05177328A (en) | Die for aluminum die casting and manufacture thereof | |
JPH04212827A (en) | Melting molding method of polymer | |
US1587742A (en) | Rubber-coated metal and method of production | |
JP2011032497A (en) | Surface-treated steel sheet for hot pressing and method for manufacturing hot-pressed member using the same | |
JPH0610079A (en) | Alloy for mold for glass | |
JPH07310175A (en) | Hard film and coating method using the same film | |
RU1799672C (en) | Method of applying protective coating on working surface of walls of casting mold for continuous billet casting | |
JPH08132186A (en) | Mold for continuous casting and manufacture thereof | |
JP4112941B2 (en) | Method of processing metal strip for paint cans with excellent formability | |
EP0453432B1 (en) | A method of forming a zinc-aluminium coating on a steel strip | |
US3937639A (en) | Process for the bright annealing and recrystallization of non-ferrous metals |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
TRDD | Decision of grant or rejection written | ||
A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20040521 |
|
A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20040604 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080611 Year of fee payment: 4 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090611 Year of fee payment: 5 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090611 Year of fee payment: 5 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100611 Year of fee payment: 6 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100611 Year of fee payment: 6 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110611 Year of fee payment: 7 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110611 Year of fee payment: 7 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120611 Year of fee payment: 8 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130611 Year of fee payment: 9 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130611 Year of fee payment: 9 |
|
S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130611 Year of fee payment: 9 |
|
R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130611 Year of fee payment: 9 |
|
S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130611 Year of fee payment: 9 |
|
R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
LAPS | Cancellation because of no payment of annual fees |