JP3254414B2 - Green fiber containing metal powder and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a metal fiber-containing green fiber and a method for producing the same. More specifically, the present invention provides a method of planting hair on a substrate, forming a nonwoven fabric or a woven fabric itself, and then forming a porous metal body by sintering, etc., for a filter, an electronic circuit board, a battery board, etc. used for various electronic devices and the like. The present invention relates to a metal powder-containing green fiber to be used and a method for producing the same.

[0002]

2. Description of the Related Art Recently, a powder molding method for obtaining a wire by kneading a metal or alloy powder with an organic binder or the like, extruding the same, and then removing and sintering the binder has attracted attention. This method greatly improves the production efficiency of metal wires. However, in the case of such a powder molding method, there is a disadvantage that the strength of an extruded product (green) from the kneaded material is small and the material is easily broken.

[0003] In order to solve this drawback, a method of manufacturing a metal wire rod in which a kneaded product of a metal or alloy powder and an organic binder is extruded, and then debinding and sintering is performed. 10μ diameter
A m is proposed to improve the strength of the green so as not to be broken by setting it to m or less (Japanese Patent Laid-Open No. 25508/1993). This prior art is for producing a wire rod having a large diameter of, for example, 1.5 mm, and the mixing ratio of a thermoplastic resin or a plasticizer as a so-called organic binder is not particularly emphasized.

On the other hand, although the particle size of the metal or alloy powder is not disclosed in the prior art, a mixture of a metal powder and an organic binder (a thermoplastic resin, a plastic material, and the like) and a solvent are kneaded. For example, a flexible metal green wire formed into a thin wire having a wire diameter of about 0.25 mm has been disclosed (JP-A-1-184205).

It is further disclosed that a metal or alloy powder having an average particle size of 50 μm or less is kneaded with an organic binder, debindered, and then sintered to obtain a rod-shaped metal sintered member of, for example, about 10 to 5 mm. (Japanese Patent Laid-Open No. 62─2)
No. 7502).

[0006]

The above prior arts are all methods for producing wires and rods. Even if these techniques are used, a sintered body of powder metal, that is, a fibrous metal, which is the object of the present invention is intended. It was not possible to obtain a metal powder-containing green fiber to obtain a porous body. In view of the above, the present invention obtains a metal powder-containing green fiber by using a metal powder having a specific particle size and specific surface area, a specific amount of a thermoplastic resin and a specific amount of a plasticizer for the thermoplastic resin. The purpose is to:

[0007]

According to the present invention, a kneaded product of a metal powder, an organic binder comprising a thermoplastic resin and a plasticizer is formed through melt extrusion means and spinning means to form green fibers. By removing the organic binder in the green fiber and subsequently sintering, a fibrous metal porous body is obtained.
0 μm or less and a specific surface area of 0.5 m ² / g or more, a thermoplastic resin of 10 to 40% by weight based on the metal powder, and a plastic resin of 10 to 50% by weight based on the thermoplastic resin. It is a metal powder-containing fiber comprising an agent (Claim 1), and the plasticizer preferably uses any one of an aromatic ester, an aliphatic ester, and a polyalkylene having a boiling point of 200 ° or more (Claim 2), Also, by attaching the metal powder to the surface of the metal powder-containing green fiber, the fiber does not break due to the adhesion between the green fibers when pulled out from a state of being wound up in a cone shape, and when handling after cutting to a certain length. It is convenient for processing and handling before the binder removal and sintering steps, for example, the green fibers do not come apart due to the sticking together (claim 3).

The metal powder-containing green fiber of the present invention is produced as follows. That is, the average particle diameter is 20 μm.
Metal powder having a specific surface area of 0.5 m ² / g or more, a thermoplastic resin of 10 to 40% by weight based on the metal powder, and 10 to 50% by weight of the thermoplastic resin. The mixture obtained by extruding a kneaded product with an organic binder made of a plasticizer by a melt extruder is immediately drawn down at a magnification of 2 to 40 times and spun while being drawn. At this time, a metal powder is adhered to the surface of the green fiber immediately after spinning and wound into a cone or the like (Claim 6) or a step of cutting the green fiber; Can be carried out (claim 7).

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, each component of the invention will be described. The metal powder in the present invention basically preferably refers to a simple metal or an alloy thereof having electrical conductivity, but it changes into the simple metal or an alloy thereof by means of a precursor, that is, sintering. If present, even if it is not electrically conductive when formed into green fibers, it is treated as a category of the metal powder according to the present invention. Specifically, for example, metals such as iron, cobalt, nickel, aluminum and copper and alloys thereof, and oxides of these metals alone can be mentioned. It is needless to say that the type of the metal powder is not limited to the above depending on the application.

Next, the metal powder used in the present invention is as small as possible particles having an average particle size of not more than 20 μm, preferably not more than 15 μm, and the particles have a specific surface area of 0.5 m ^2.
/ g or more, preferably 1 m ² / g or more, and should be used only in a range having a state as large as possible. Here, first, the average particle diameter is measured by a general method such as a laser diffraction scattering method or a sedimentation method, and the specific surface area is determined by a gas adsorption method, a BET specific surface area method, or the like.

Here, the average particle size is particularly related to the formation of a green fiber, and the specific surface area is particularly related to the adsorptivity (adhesion) of the thermoplastic resin to the metal powder. Accordingly, the two are inevitably linked, but the effect of the bond is maximized particularly when the average particle size is 20 μm or less and the specific surface area is 0.5 m ² / g or more as described above. In other words, if a metal powder having an average particle size larger than 20 μm is contained, the specific surface area is assumed to be 0.5 m ² / g.
Even if it is larger, there is a limit in spinning a finer green fiber, and it is difficult to spin or to obtain a green fiber having a stable diameter even if it can be spun. Conversely, when the specific surface area is smaller than 0.5 m ² / g, that is, the degree of unevenness is small, and when approaching a spherical shape, the thermoplastic resin becomes difficult to be adsorbed by the metal powder, the strength of the green fiber is weak, and the Is inappropriate.

When the metal powder is used under the above conditions, it is needless to say that the metal powder is not limited to one kind but may be used in a mixture of two or more kinds. The above may be mixed. Next, a thermoplastic resin which is one of the organic binder compositions used for the metal powder will be described.

First, the thermoplastic resin is a good binder for the metal powder under the above-mentioned conditions, and can be easily thermoplasticized in an extruder and easily spun with appropriate strength. It is selected as one that can meet the conditions required for processing (nonwoven fabric, woven fabric, etc.). Accordingly, there is basically no particular limitation on the type (constituent molecule, presence or absence of crystallinity, etc.) as long as these are satisfied.

As the resin, for example, polystyrene,
Atactic polypropylene, copolymer of ethylene and vinyl alcohol, polymethyl methacrylate, polyvinyl alcohol (degree of saponification of 80% or more), polyvinyl butyral, polyethylene, polyacrylonitrile, styrene acrylic copolymer, polystyrene, polyethylene glycol, Examples include polylactic acid, various cellulosic plastics, various nylons, polyurethanes, polyesters, thermoplastic elastomers, and thermoplastic polyimides.

Depending on the performance required, the resin is selected from various ones, including each resin. Among them, when debinding and sintering are performed, an aliphatic hydrocarbon polymer containing oxygen is preferable. . For example, any of polyvinyl butyral, polyvinyl alcohol ethylene / vinyl alcohol copolymer, and polymethyl methacrylate in the preceding examples can be mentioned. These sinter the resulting metal powder-containing green fibers further, but the burning temperature of the thermoplastic resin itself in the sintering is also low, so that it is incinerated and removed faster. Also, the metal powder remaining after sintering is densely connected to each other and maintains a fiber state. Of course, the use of such a resin is based on the reason that no waste gas which causes pollution is generated.

The content of the thermoplastic resin is desirably as small as possible in order to give the properties as a metal to a greater extent. However, it is necessary to efficiently bind the metal powders together and set the most preferable range on the premise of conditions such as good spinnability (moldability) as green fibers. In the present invention, as a range satisfying these various conditions, 10 to 4
The range of 0% by weight and the more satisfactory range is 15 to
35% by weight. That is, if the content is less than 10% by weight, even if the metal powder satisfies the above conditions, the powders are not completely connected due to a sufficient bond, and as a result, they are cut off halfway even when spun into green fibers. And the production of continuous green fibers becomes difficult. On the other hand, when the content exceeds 40% by weight, the content of the metal powder is small, and the metal properties based on the powder provided by the metal powder are not sufficiently exhibited. It is difficult to obtain.

Next, the plasticizer used in the present invention will be described. The metal powder-containing green fiber is composed of at least a metal powder and a thermoplastic resin. When only these two components cannot be spun into green fiber, or when green fiber is obtained, it is too hard to cut accurately into short fibers (chopped fibers) required for post-processing. Etc. In order to solve such inconveniences at a glance and stably produce green fibers in any combination of the above two components, the present invention particularly uses a plasticizer in combination with the third component. Furthermore, in the present invention, the content of the plasticizer is in the specific range described below, and the maximum effect is exhibited in this range.

The plasticizer adjusts the plasticized state of the metal powder and the thermoplastic resin to a certain level with respect to the plasticized state by heating, and is always stable in any combination of the two. Any type can be used as long as it has the function of performing continuous spinning. However, in actual selection, it is well compatible with the thermoplastic resin and does not evaporate or decompose at the molding temperature of the green fiber. Furthermore, a small amount of addition promotes plasticization more efficiently, and furthermore, bleed out ( It is preferable to test and confirm in advance in consideration of not exuding from the fiber).

Taking the above conditions into consideration, preferred plasticizers are specifically exemplified as follows. First, there are three types of aromatic esters having a boiling point of 200 ° C. or higher, aliphatic esters having a boiling point of 200 ° C. or higher, and polyalkylene ethers having a boiling point of 200 ° C. or higher. As the aromatic ester, for example, a phthalic acid-based ester is preferable, and examples thereof include dibutyl phthalate, dioctyl phthalate, diisodecyl phthalate, and butylbenzyl phthalate.

On the other hand, examples of the fatty acid ester include dioctyl adipate, dioctyl sebacate, dioctyl azelate and the like. Examples of the polyalkylene ether include polyethylene glycol, polyethylene glycol dimethyl ether, and polyethylene glycol benzoate.

The content of the plasticizer may be determined depending on the spinnability and the strength and brittleness of the green fiber after spinning, depending on the type of the thermoplastic resin and the plasticizer used, but is preferably as small as possible. If the content exceeds 50% by weight with respect to the thermoplastic resin, bleed out from the yarn is severe, causing blocking between green fibers or even having no properties as a green fiber having more metallic properties. This is not preferred for reasons such as On the other hand, if the content is less than 10% by weight, even if the thermoplastic resin has a low melting point and a low viscosity and has a composition in which the minimum amount of the metal powder is mixed with the thermoplastic resin, if the thermoplastic resin contains a large amount of the metal powder, Does not exhibit the effect of chemical conversion. Therefore, at least 10% by weight is required.

Further, if necessary, a dispersant, a lubricant, an anti-blocking agent and the like may be appropriately added to these three main components. Green fiber shape (cross section)
Is generally circular, but may have an irregular cross section. The average diameter (diameter) of the cross-sectional shape is not particularly limited as long as it is within a range generally called a fiber.

Next, a method for producing the metal powder-containing green fiber of the present invention will be described. First, the three main components of the metal powder, the thermoplastic resin, and the plasticizer described above are mixed within the range of each composition ratio, but the mixing procedure and the mixing method are not limited. For example, a predetermined amount of metal powder and a thermoplastic resin are previously heated to a temperature at which the resin is plasticized, and mechanically mixed (kneader or the like) under pressure to form a uniformly dispersed state.

Next, a predetermined amount of a plasticizer is added to this state and mixed again under the same conditions to uniformly disperse all components. Next, the obtained mixture is cooled, pulverized, and further supplied to an extruder, heated and kneaded, and pelletized. (Kneading mixture) The obtained pellets are supplied to an extruder whose barrel has been adjusted to a melting temperature, and are discharged from a die. Here, after discharging, the material is not cooled and taken off as it is, but is drawn at a draw-down magnification of 2%.
It is withdrawn by a factor of up to 40 times, preferably 5 to 30 times. Here, the above-mentioned draw-down magnification is a value obtained from the diameter, which is a value obtained from the nozzle diameter d ₁ and the diameter d ₂ of the green fiber after final solidification, that is, d ₁ / d ₂ = 2.
-40 (5-30). Therefore, the diameter of the discharge port provided in the base is inversely proportional to the average diameter of the target green fiber. Thus, by the above-mentioned drawing operation, the metal powder and the thermoplastic resin are oriented in the drawing direction, and the strength of the green fiber itself is improved.

These withdrawal effects are maximized at a withdrawal magnification of 2 to 40 times. That is, 2
If it is less than twice, the strength is insufficient, and when spinning a small-diameter green fiber, the spinning is performed from a small spinneret, so that the metal powder may be clogged in the spinneret. On the other hand, if the drawdown exceeds 40 times, the above effect is not further improved, the effect of the thermoplastic resin as a binder is reduced, and thread breakage sometimes occurs during the drawdown operation.

By pulling down at the above magnification, physical properties such as bending resistance are improved and workability into a woven fabric or the like is further improved. Have the desired hardness, which has the added advantage that they can be easily and accurately cut into shorter lengths of green fiber.

The green fiber thus produced can be used for post-processing as it is, but in some cases, the green fiber may cause blocking with time. In particular, a method for preventing the blocking of the green fiber will be described below. For example, when a green fiber that causes blocking is wound up in a cone shape, the green fibers stick together when being unwound from the cone and cannot be smoothly unwound, and the unwound green fiber is cut or torn. In the case of cutting into a short fiber form immediately after spinning, the short fibers may stick together and become solid. These cause a problem that processing and handling of the metal powder-containing green fiber prepared with great difficulty become difficult. The spun green fiber containing a metal powder according to the present invention solves such a problem by further adhering the metal powder to the surface thereof, so that the green fibers are not stuck together and the subsequent processing and handling is facilitated. Further, such a green fiber is used as a metal porous body after debinding and sintering, that is, it is important as a property required to have a large surface area. After debinding and sintering, the metal powder containing the metal powder of the present invention becomes a part of the surface, and the surface of the metal porous fiber becomes significantly uneven. This allows the surface area to be dramatically increased.

Next, the metal powder adhered to the surface will be described. There is no particular limitation on these metal powders, and they can be used in a single metal state or in an alloy state. But,
Considering that the metal powder-containing green fiber of the present invention goes through a binder removal and sintering process, it is considered that the same powder as the metal powder used for the spun fiber is most easily bonded by sintering. However, depending on the selection combination of metal materials, there are also combinations that are more easily bonded by reaction than the same metal, and these combinations can be used positively. The particle size of the metal powder that can be used is not particularly limited, but is preferably equal to or less than the diameter of the spun green fiber and equal to or more than 1/100 of the diameter. If the diameter of the spun green fiber is larger than the diameter of the spun green fiber, adhesion to the green fiber becomes insufficient, and the effect of the present invention of separating green fibers from each other is reduced. If it is less than this, the green fibers can be separated from each other, but the surface of the porous metal fibers after binder removal and sintering does not have irregularities, and the surface area cannot be increased.

The method for adhering the metal powder is not particularly limited. However, when the metal powder is adhered during spinning, the metal powder is sprayed onto the green fiber by a spraying method and adhered, or a general oiling device is used. In this manner, a method of transferring the metal powder by adding green fibers on the roller to which the metal powder is adhered, or a method of attaching the metal powder with a brush or the like is used. Further, to the cut green short fiber-like state, the metal powder is added to the green short fiber while being sieved without coagulation, and sufficiently adhered by a rotary stirrer or the like.

[0030]

<Example 1> First, nickel powder having an average particle size of 1.66 μm and a specific surface area of 2.2 m ² / g (product number # 210 manufactured by Inco Corporation) and 27.5% by weight of polyvinyl chloride Butyral (Sekisui Chemical Co., Ltd., part number BL-1) was mixed with a ribbon mixer, and this was further mixed at 120 ° C.
, And stirred and mixed in a molten state for 1 hour. Then, 29% by weight of dibutyl phthalate was added to the mixed amount of polyvinyl butyral, followed by stirring and mixing under the same conditions for 1 hour. . The obtained mixture was cooled and pulverized into a powder to obtain a mixed powder.

The three-component mixed powder was further supplied to a plunger type extruder (barrel temperature: 50 to 130 ° C.) to be pelletized. Then, this was fed to a 30 mm single screw extruder (barrel temperature: 50 to 150) having a discharge hole of 1 mmφ × 6 holes.
° C), and melt-spun while being drawn down at a draw ratio of 5.6, to bundle six green single fibers, which were wound into a cone as a multifilament. The obtained green single fiber was circular (cross section) and had a diameter of 100 ±
It was constant at 10 μm.

Immediately afterwards, in order to confirm the post-processability, the wound multifilament having a total length of 200 m was continuously supplied to a yarn cutter adjusted so as to be cut to a length of 2 mm and cut. At this time, the cutter blade could be cut to 2 mm extremely accurately without any trouble such as tooth spilling or breaking due to shearing force during the cutting. In addition, the cut multifilaments had no blocking, and were separated into individual green short fibers. Example 2 Nickel powder in Example 1, 27.5% by weight of ethylene / vinyl alcohol copolymer (Nippon Synthetic Chemical Co., Ltd., part number 3835) and polyethylene glycol benzoate (Sanyo Chemical Industry Co., Ltd.) Company, product number EB-200) was prepared in an amount of 29% by weight based on the ethylene / vinyl alcohol copolymer, and mixed in a pressure kneader, kneaded by an extruder, and pelletized in the same procedure as in Example 1. Was done. Then, the obtained pellets were continuously melt-spun in the same manner as in Example 1. However, the heating temperature by the pressure kneader was 150 ° C, and the barrel temperature of the extruder in pelletizing and melt spinning was 70 to 200.
C.

The spinning was carried out continuously for 2 hours, during which the yarn was smoothly finished without breakage. The diameter of the obtained green fiber was constant at 180 μm.
It was continuously supplied to a cutter adjusted to a cut length of mm to cut. As in the case of Example 1, it was possible to cut smoothly without any trouble. <Example 3> Average particle size 3.7 μm, specific surface area 1.52 m
² / g of nickel powder, 25.0% by weight of polyvinyl butyral (BL-1) based on the nickel powder, and 22.2% by weight of dioctyl phthalate based on the polyvinyl butyral were prepared and kneaded sufficiently. The mixture was mixed with a pressure kneader under the same conditions as in Example 1 and pelletized.

Next, the obtained pellets were melt-extruded and melt-spun using a die in the same manner as in Example 1, and were taken out in a multifilament form. However, in this case, the withdrawal magnification was 8 times. The continuous spinning was carried out for 3 hours, during which time there was no breakage of the yarn or disturbance of the fiber diameter, and the spinning was smoothly performed. The obtained green fiber diameter is 12
It was wound on a cone as a multifilament having six bundles of 0 μm.

Next, the wound multifilament
Continuously supplied to the same cutter as in Example 1.
And cut into 2 mm lengths. Question without blocking
I was able to cut with the same length without a title. <Example 4> (Example of using antiblocking agent) In Example 1, 27.5 layers of polyvinyl butyral was used.
The amount of dibutyl phthalate used is 33.4% by weight.
The outside was kneaded and spun under exactly the same conditions. Especially thread breakage
Without trouble, into a cone as a multifilament
Could be wound up. Next, after one day,
I cut it with The result is the cutting itself
Is smooth but green staple fiber one by one
Short mulch that cannot be completely separated and is partially blocked
The filament was mixed and cut. This phenomenon is called phthalate
This is because the amount of dibutyl acid was higher than that in Example 1.
Slightly bleeds out over time, on the wound cone
It is considered that the same nickel powder was included in the cut pieces.
Add 6% to fiber weight while stirring slowly
did. After stirring for about 20 minutes and checking the condition
Short multifilaments that had been blocked completely
The fibers could be separated into short fibers one by one. In this state
Left for one week and checked again, but blocking recurred
I never did. <Example 5> The short fiber of Example 4 was placed in a nitrogen atmosphere for 400 hours.
Debinding at 20 ° C for 20 minutes and holding at 900 ° C for 10 minutes
Thus, a sintered fibrous metal porous body was obtained. This
Specific surface area of porous fibrous metal
Specified. The result is 0.08m ^Two/ g. <Comparative Example 1> (Specific surface area of metal powder is 0.5 m^Two/ g
In the case of Example 1, the average particle size was 12.9 μm, and the specific surface area was 0.1.
4m^Two/ g nickel powder
After mixing and kneading the three components,
Spinning and winding into green fiber without qualitatively
Was. Under these withdrawal conditions, continuous winding is not possible.
It was completed, but when you started the withdrawal and rolled it up,
When the rate is about double, thread breakage starts to occur, and
When it was doubled, thread breakage occurred frequently, and the spinning was stopped.

Observation of the cross sections of the broken portion and the non-broken portion with an enlarged micrograph shows that there is a difference in the dispersion state of the nickel powder between the two portions, and that the nickel powder is largely dispersed in the broken portion. That is, it is considered that the nickel powder was not uniformly dispersed in the polyvinyl butyral, which is considered to be because the surface of the nickel powder was spherical (not uneven) and polyvinyl butyral was not sufficiently adsorbed. <Comparative Example 2> (When the content of the thermoplastic resin is less than 10% by weight) In Example 1, except that 6% by weight of polyvinyl butyral and 60% by weight of dibutyl phthalate were used, the same conditions as in Example 1 were used. The components were mixed and kneaded, and pelletized. At the time of this pelletization, as compared with that of the example, the extrusion before cutting into pellets was not smooth but the surface was uneven, rough, and wet. However, since pelletization was completed, melt spinning was attempted in the same manner as in this example. However, winding was performed with almost no pull-down, but the yarn immediately broke, and it was impossible to form green fibers. <Comparative Example 3> The green fiber obtained in the same manner as in Example 4 was left as it was for one week without attaching nickel powder. As a result, the fibers were stuck together without being separated due to the blocking. Further, the green fiber to which the nickel powder was not adhered was subjected to the same binder removal and sintering as in Example 5 before the fibers were stuck together by blocking, and the specific surface area was measured.
m ² / g, which was smaller than the specific surface area to which the nickel powder was attached by 以上 or more. <Comparative Example 4> (When the draw-down magnification is large) Using the same composition and nozzle as in Example 1, a spinning test was performed while increasing the draw-down magnification. Thread breakage began to occur immediately after exiting the nozzle at 40x, and more at 45x. When the yarn obtained at 45 times was observed with a magnified micrograph, it was found that the nickel powder and polyvinyl butyral were separated.

[0037]

By using a metal powder having a specific particle size and specific surface area, a specific amount of a thermoplastic resin and a specific amount of a plasticizer for the resin, an extremely fine fibrous metal powder-containing green fiber is obtained. It is easy to process and handle by attaching metal powder to the surface of the green fiber. In addition, the porous metal obtained by debinding and sintering the green fiber has the surface Becomes uneven and the specific surface area can be increased.

──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Yoko Takai 1006 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Akira Hashimoto 1-1-1, Matsushita-cho, Moriguchi-shi, Osaka Matsushita Battery Industry (56) References JP-A-8-213026 (JP, A) JP-A-63-95150 (JP, A) JP-A-7-3302 (JP, A) JP-A-7-97270 (JP, A) A) (58) Field surveyed (Int. Cl. ⁷ , DB name) D01F 1/00-8/18 D01F 9/08 D06M 11/83 B22F 5/00-5/12

Claims (7)

(57) [Claims] 1. A green fiber is formed by kneading a kneaded product of mainly a metal powder, an organic binder composed of a thermoplastic resin and a plasticizer through melt extrusion means and spinning means, and then removes the organic binder in the green fiber. And subsequently sintering to obtain a fibrous metal porous body, wherein the metal powder has an average particle size of 20 μm or less and a specific surface area of 0.5 m ² / g or more. A green fiber containing metal powder, comprising 10 to 40% by weight of a thermoplastic resin and 10 to 50% by weight of a plasticizer with respect to the thermoplastic resin. 2. The method according to claim 1, wherein the plasticizer has a boiling point of 200 ° C.
Green powder-containing green fibers that are any of the above aromatic esters, aliphatic esters and polyalkylene ethers. 3. The green fiber containing a metal powder according to claim 1, wherein a metal powder is attached to the fiber surface. 4. A metal powder having an average particle diameter of 20 μm or less and a specific surface area of 0.5 m ² / g or more, a thermoplastic resin of 10 to 40% by weight based on the metal powder, and the thermoplastic resin. A mixture extruded with a melt extruder from a kneaded body with an organic binder comprising 10 to 50% by weight of a plasticizer based on a resin,
A method for producing a metal fiber-containing green fiber, wherein the fiber is immediately drawn down at a magnification of 2 to 40 times and spun while being drawn. 5. The plasticizer according to claim 4, wherein the boiling point is 200 ° C.
A method for producing a metal fiber-containing green fiber which is any of the above aromatic esters, fatty acid esters and polyalkylene ethers. 6. The method according to claim 4, wherein a metal powder is attached to the surface of the green fiber immediately after spinning.
3. The method for producing a metal fiber-containing green fiber according to item 1. 7. The method according to claim 4, further comprising a step of producing green fibers, a step of cutting the fibers, and a step of attaching metal powder to the surface of the cut fibers. 3. The method for producing a metal fiber-containing green fiber according to item 1.