【発明の詳細な説明】
く産業上の利川分野〉
本発明は、金属粉末および含潤滑剤金属粉末の保存に適
した梱包体に関するものである．〈従来の技術〉
一般に、工業的に還元焼鈍および／または粉砕微細化さ
れた金属粉末は、表面状態がきわめて活性であるため、
雰囲気中の酸素や吸着水分中の酸素と結びつき、酸化物
や水酸化物を作りやすく、錆などを発生しやすい傾向に
ある．粉末冶金用に用いられる金属粉末の場合には酸化
物・水酸化物，う生戒や含有酸素量の増加により品質特
性に異常を来たす時がある．また保温用カイロに用いら
れる場合は事前に酸化が進行し、製品の発熱特性がそこ
なわれ、商品価値を失う時がある．そのため使用前にお
ける金属粉末の保存方法がきわめて重要であった．
また、近年粉末冶金などの分野においては、金属粉末と
潤滑剤その他の添加剤の混合におけるコストを低減する
ため多量の原料を１回の作業で混合後、その混合済金属
粉末を貯蔵し長期間を経て使用される場合がある．その
とき、これらの潤滑剤の中にはきわめて吸湿性の高いも
のが多く、潤滑剤が吸収した湿分を混合状態にある金属
粉末が受けとり酸化物，水酸化物を作って鯖が発生ずる
という例がきわめて多い．
そこで、以上のような金属粉末および含潤滑剤金属粉末
の保存にはポリエヂレン等の樹脂製膜やアルミニウム箔
などの梱包容器が用いられ、包み口を加熱圧着して梱包
容器外側と内側の雰囲気を遮断し外界からの酸素．水分
の浸入防止が図られてきた．
しかし、樹脂製膜やアルミニウム箔などには肉眼による
目視ＩＩ！認や簡便な調査方法では検知不能なビンホー
ルや樹脂製膜の加熱圧着時の不備による雰囲気の漏れな
どの問題があり、樹脂膜を通した微量の水分透過が長期
保存の際は無視できないなどの問題点があった．
前記問題点を解決するため、従来は高純度窒素ガスや乾
燥空気と共に金ｒｆ％粉末を封入・梱包したり、梱包用
樹脂製膜の厚みを増加させて透過水分量，酸素の低減を
図ったり、多重梱包体を用いたり、ｌｌｌ包用樹脂製膜
の加熱圧着封入時における信頼性を向上させるなどの対
策がとられているが、設備費．梱包材料費が高くコスト
的に不利であったり、多大の工数を要し、人件費が無視
できないなどの欠点を有している．
また気孔を有する繊維製袋などにより包まれたシリカゲ
ルなどの乾燥剤を金属粉末と同時に梱包する対策がとら
れているが、乾燥剤が飽和吸着量を越えて吸湿すると乾
燥剤から水分があふれ、周囲の金属粉末をかえって錆さ
せるという欠点があった．また乾燥剤が梱包袋内部の露
点を低減させるため梱包体内．外の露点差をより増大さ
せ、かえって梱包樹脂膜を透過する水分が増えるという
欠点もあった．
く発明が解決しようとする課題〉
本発明の目的は、錆の発生を抑え、比較的長期保存に耐
えられる金属粉末の梱包体を提供するものである．
また他の目的は、梱包作業が比較的容易な金属粉末の梱
包体を提供するものである．
〈課題を解決するための手段〉
本発明は前記課題を解決するために、金属粉末または含
潤滑剤金属粉末の梱包体に関し、各秤ボリエヂレン製膜
と乾燥剤を用いて様々の梱包様式を試し、最も効果的な
梱包体を見い出したものである．
ずなわら、本発明は、紙装あるいはフレキシブルコンテ
ナー等の外装内に金属粉末を二重の合成樹脂膜で気密に
包み、かつ該合戊樹脂膜間に乾燥剤を封入したことを特
徴とする金属粉末の梱包体である．
く作用〉
第１図は、本発明による梱包体の模式図で、１は金ＢＦ
Ａ末または含潤滑剤金属粉末、２はポリエチレン製内側
樹脂膜、３はポリエチレン製外側樹脂膜、４は繊維製布
．紙などに包まれたシリカゲル等の乾燥剤、５および６
は梱包時に生じる空気を含む空間、７は大気、８は台ま
たは床面である．外側樹脂膜３および内側樹脂膜２はそ
れぞれ内包物を押入後包み口を加熱圧着により接着され
各樹脂膜を境に外と内の雰囲気が完全に遮断されている
．
以上が本発明の梱包体の基本的要件であるが、現実には
、これらを移送する際、ポリエチレン等の樹脂膜に疵を
作らないために、さらに紙装あるいはフレキシブルコン
テナー等の外袋で保護される．
第２図は、ポリエチレン製フィルムの厚みと水蒸気透過
度（透淘度）の関係を示したものでありフィルムには高
圧威形と低圧或形の２′Ｍｉｆｌがある．一般に膜厚２
０μＩｌ〜１５０μ一の範囲では厚い方が水蒸気透過量
が少く、また同じ厚みでは高圧戒形フィルムの方が透過
量が少い．従来より厚さを増し、威形圧力を上げれば有
利な事が知られているが膜（フィルム）の製造コストが
高くなり不利である．また多重梱包にすると膜厚を増し
たと同じ効果を生じ有利であるが複数回の梱包は作業工
数的および材料費的なコストから不利であることは容易
に想定される．
第３図は、本発明を導くに至った主要実験の模式図であ
る．実験に用いた試料は表１に示す特性を持つミルスゲ
ール還元鉄粉と水アトマイズ鉄粉の２種類で（ａ）〜（
ｒ）各々に５ｋｇずつ用いた．乾燥剤は和紙に包んだシ
リカゲルを２０ｇ用いた．また実験前にｌＯＯメッシュ
の網で篩い１００メッシュより大きな錆の混入がないこ
とを確かめている．（ａ）〜（ｄ）は大気で封入し、（
ｅ）， （ｆ）はＮ，封入を行ってい（ａ）， （ｂ）
は従来頻繁に用いられた方法であり、１本発明である．
また用いた袋は２１０ｍｍＸ ２９５ｍｍ ｌ’ｉさ
６０μｍのポリエヂレン製膜で外観上亀裂等がなく、圧
着加熱も良好である。雰囲気温度３５℃相対湿度９０％
にて２４時問および１６８時間保持後各試材より１００
ｇ抽出し一１４８メッシュ，＋６５メッシュ，＋８０メ
ッシュ中の錆の個数を調査した。その結果を表２に示す
．表２よりミルスケール還元鉄粉，水アトマイズ扮とも
、また２４時間，１６８時間とも本発明の（Ｃ）が共通
して錆発生が少ない．また（ｄ）も請発生が少ないがコ
スト高となり好しくない．
表
１
なお、本実験ではポリエステル股を用いたが他の樹脂膜
やアルミニウム箔でも同様の扱いができ、その効果も同
じであった．
また梱包方法は、あらかじめ乾燥剤をとりこんだ二重筒
の樹脂膜を外装内にセットしておき、これに金属粉を投
入することが能率的である．〈実施例〉
逅ルスケール還元鉄粉を紙装に２５ｋｇ，フレキシブル
コンテナーに５０αｋｇ梱包した．両方とも、その内袋
には膜厚６０μ糟のポリエステル膜を使用した．乾燥剤
は２０ｇ単位で繊維製の袋に入れたものを用いた．
第４図（ａ）は２５ｋｇ詰め紙装の荷姿であり、（ｂ）
はその断面図である．この場合乾燥剤は１袋用いた．第
５図（ａ）は５００ｋｇＦ，Ｊｉめフレキシブルコ，ン
テナーの荷姿であり、（ｂ）はその断面図である．この
場合乾燥剤は８袋用いた．
これらを６月から８月にわたる約３ケ月間通常の物品倉
庫で保存したのち、各々１００ ｇ ． ２００ ｇ
をサンフ゜リングし一ト４８メッシュ，＋６５メッシュ
，＋８０メッシュ中の錆の個数を調査した結果、錆発生
が全く見られなかった。[Detailed Description of the Invention] Industrial Field> The present invention relates to a package suitable for storing metal powder and lubricant-containing metal powder. <Prior art> In general, industrially reduction annealed and/or pulverized metal powder has an extremely active surface state.
It combines with oxygen in the atmosphere and oxygen in adsorbed moisture, tends to form oxides and hydroxides, and tends to cause rust. In the case of metal powders used for powder metallurgy, abnormalities in quality characteristics may occur due to oxides, hydroxides, caries, and an increase in the amount of oxygen content. Furthermore, when used in heat-retaining body warmers, oxidation progresses beforehand, damaging the product's heat-generating properties and sometimes causing it to lose its commercial value. Therefore, the method of preserving metal powder before use was extremely important. In addition, in recent years, in fields such as powder metallurgy, in order to reduce the cost of mixing metal powder with lubricants and other additives, large amounts of raw materials are mixed in one operation, and the mixed metal powder is stored for a long period of time. It may be used after. At that time, many of these lubricants are extremely hygroscopic, and the metal powder in the mixture absorbs the moisture absorbed by the lubricant, creating oxides and hydroxides, which causes the formation of mackerel. There are many examples. Therefore, packaging containers made of resin films such as polyethylene or aluminum foil are used to store metal powders and lubricant-containing metal powders as described above, and the openings are heated and crimped to keep the atmosphere between the outside and inside of the packaging container. Block out oxygen from the outside world. Efforts have been made to prevent moisture from entering. However, visual inspection with the naked eye is necessary for resin films, aluminum foil, etc. There are problems such as bottle holes that cannot be detected using simple inspection methods and atmospheric leakage due to imperfections in heat-pressing the resin membrane, and trace amounts of moisture permeation through the resin membrane cannot be ignored during long-term storage. There was a problem. In order to solve the above problems, conventional methods have included enclosing and packaging gold RF% powder together with high-purity nitrogen gas and dry air, and increasing the thickness of the packaging resin film to reduce the amount of permeated moisture and oxygen. Measures have been taken, such as using multiple packages and improving reliability when sealing resin membranes for Ill packaging by heat-pressure bonding, but equipment costs are high. It has drawbacks such as high cost of packaging materials, which is disadvantageous in terms of cost, and a large amount of man-hours required, which can't be ignored. Measures have also been taken to package a desiccant such as silica gel wrapped in a fiber bag with pores at the same time as the metal powder, but if the desiccant absorbs moisture beyond its saturated adsorption capacity, water overflows from the desiccant. The drawback was that it would actually cause the surrounding metal powder to rust. In addition, the desiccant is used inside the packaging to reduce the dew point inside the packaging bag. This also had the disadvantage of increasing the difference in dew point outside and increasing the amount of moisture that permeated through the packaging resin membrane. Problems to be Solved by the Invention The object of the present invention is to provide a metal powder package that suppresses the occurrence of rust and can be stored for a relatively long period of time. Another object of the present invention is to provide a metal powder package that is relatively easy to pack. <Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention has tried various packaging formats using various scale polyethylene films and desiccants regarding packages of metal powder or lubricant-containing metal powder. , we have found the most effective packaging. However, the present invention is characterized in that the metal powder is airtightly wrapped in a double synthetic resin film within an exterior packaging such as paper packaging or a flexible container, and a desiccant is sealed between the synthetic resin films. It is a package of metal powder. Fig. 1 is a schematic diagram of a package according to the present invention, in which numeral 1 indicates gold BF.
A powder or lubricant-containing metal powder; 2, polyethylene inner resin film; 3, polyethylene outer resin film; 4, fiber cloth. Desiccant such as silica gel wrapped in paper etc., 5 and 6
is the space containing air generated during packaging, 7 is the atmosphere, and 8 is the stand or floor surface. The outer resin film 3 and the inner resin film 2 are each sealed with heat and pressure bonded at their openings after the inclusions have been inserted, so that the atmosphere between the outside and the inside is completely shut off with each resin film as a boundary. The above are the basic requirements for the packaging of the present invention, but in reality, when transporting these, in order to prevent scratches on the resin film such as polyethylene, it is further protected with paper packaging or an outer bag such as a flexible container. It will be done. Figure 2 shows the relationship between the thickness and water vapor permeability of polyethylene films, and there are two types of films: high-pressure and low-pressure 2'Mifl. Generally film thickness 2
In the range of 0 μl to 150 μl, the thicker the film, the lower the amount of water vapor permeation, and at the same thickness, the higher the pressure film, the lower the amount of permeation. It is known that it is advantageous to increase the thickness and pressure of the film compared to conventional methods, but this increases the production cost of the film, which is disadvantageous. Also, multiple packaging has the same effect as increasing the film thickness and is advantageous, but it can be easily assumed that multiple packaging is disadvantageous due to the cost of man-hours and materials. Figure 3 is a schematic diagram of the main experiments that led to the present invention. The samples used in the experiment were two types, Milsgaer reduced iron powder and water atomized iron powder, which had the characteristics shown in Table 1.
r) 5 kg was used for each. The desiccant used was 20g of silica gel wrapped in Japanese paper. Also, before the experiment, we checked that there was no rust that was larger than a 100 mesh sieve using a lOO mesh screen. (a) to (d) are sealed in the atmosphere, and (
e), (f) are N, encapsulation is performed (a), (b)
This is a method that has been frequently used in the past, and is one of the methods of the present invention. The bag used was made of a polyethylene film measuring 210 mm x 295 mm and 60 μm in diameter, and had no cracks or the like in appearance, and could be pressed and heated well. Atmosphere temperature 35℃ relative humidity 90%
After holding for 24 hours and 168 hours, 100 samples were obtained from each sample.
The number of rust particles in 148 mesh, +65 mesh, and +80 mesh was investigated. The results are shown in Table 2. Table 2 shows that (C) of the present invention has less rust in both mill scale reduced iron powder and water atomized powder, and also for 24 hours and 168 hours. In addition, (d) is also undesirable because the number of requests is low, but the cost is high. Table 1 Although polyester crotches were used in this experiment, other resin films or aluminum foils could be used in the same way, and the effects would be the same. In addition, an efficient packaging method is to set a double-tube resin film containing desiccant in advance inside the package, and then toss the metal powder into this. <Example> 25kg of hard scale reduced iron powder was packed in paper and 50kg in a flexible container. In both cases, a polyester membrane with a thickness of 60 μm was used for the inner bag. The desiccant used was packed in 20g units in a fiber bag. Figure 4 (a) shows the packaging of the 25 kg paper packaging, and (b)
is its cross-sectional view. In this case, one bag of desiccant was used. Fig. 5(a) shows the packaging of a 500kgF flexible container, and Fig. 5(b) shows its cross-sectional view. In this case, 8 bags of desiccant were used. After storing these in a regular warehouse for about 3 months from June to August, 100 g. 200g
As a result of inspecting the number of rust particles in 48 mesh, +65 mesh, and +80 mesh, no rust was observed.
〈発明の効果〉
本発明により、比較的容易に、また低コストで金属む｝
末の品質特性をｔｍなわずに長期保存することが可能に
なった．<Effects of the Invention> According to the present invention, metal can be formed relatively easily and at low cost.
It is now possible to store the product for a long time without losing its quality characteristics.
【図面の簡単な説明】[Brief explanation of drawings]
第ｌ図は本発明の模式図、第２図はフィルムの厚みと透
湿度の関係を示すグラフ、第３図は各種梱包態様による
実験模式図、第４図は（ａ）は２５ｋｇ紙装梱包荷姿、
（ｂ）はその断面図、第５図（ａ）は５００ｋｇフレキ
シブルコンテナー梱包荷姿、（ｂ）はその断面図である
．
ＩＯ・・・フレキシブルコンテナー
１１・・・上蓋、 １２・・・外袋下払出口、
！３・・・窒素ガス．
・・・金属粉末、 ２・・・内側樹脂膜、・・・外
側樹脂膜、
・・・繊細製布，紙などに包まれた乾燥剤、・・・空気
を含む空間、６・・・空気を含む空間、・・・大気、
８・・・台または床、・・・紙製外袋、Fig. 1 is a schematic diagram of the present invention, Fig. 2 is a graph showing the relationship between film thickness and moisture permeability, Fig. 3 is a schematic diagram of experiments using various packaging modes, and Fig. 4 (a) is a 25 kg paper packaging. Packing,
(b) is a sectional view of the same, FIG. 5(a) is a 500 kg flexible container packaged, and (b) is a sectional view of the same. IO...Flexible container 11...Top lid, 12...Outer bag bottom outlet,
! 3...Nitrogen gas. ...Metal powder, 2.Inner resin film, ...Outer resin film, ...Drying agent wrapped in delicate cloth, paper, etc., ...Space containing air, 6.Air A space containing...atmosphere,
8...stand or floor,...outer paper bag,