JP3509408B2 - Iron-based powder mixture for powder metallurgy excellent in fluidity and moldability and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an iron-based powder mixed powder for powder metallurgy, which is obtained by adding a lubricant, graphite powder, copper powder or the like to iron-based powder such as iron powder or alloy steel powder in advance, and further mixing. Specifically, the present invention relates to an iron-based powder mixture for powder metallurgy, which has little segregation of the above-mentioned additives and generation of dust, and has excellent fluidity and moldability in a wide temperature range from room temperature to about 200 ° C. .

[0002]

2. Description of the Related Art Iron-based powder mixtures for powder metallurgy include iron powder, alloy powder such as copper powder, graphite powder, iron phosphide powder, and, if necessary, powder for improving machinability, zinc stearate. ,
It is generally produced by mixing a lubricant such as aluminum stearate or lead stearate. Such lubricants have been selected from the viewpoints of mixing properties with metal powders and dissipating properties during sintering.

In recent years, along with the increasing demand for higher strength of sintered members, Japanese Patent Laid-Open No. 2-156002 and Japanese Patent Publication No. 7-103404.
As disclosed in U.S. Pat. No. 5,256,185 and U.S. Pat. No. 5,368,630, a warm compacting technique has been proposed which enables high density and high strength of a compact by compacting while heating a metal powder. It was Lubricant in the molding method, in addition to the viewpoint of mixing property with metal powder, dissipating property during sintering,
Lubricity during heating is emphasized.

That is, by mixing a mixture of a plurality of types of lubricants having different melting points with the metal powder, a part of the lubricant is melted at the time of warm compaction to uniformly disperse the lubricant among the metal powder particles. It reduces the frictional resistance between particles and between the compact and the mold to improve the moldability. However, such a metal powder mixture has the following drawbacks.

That is, first, such a metal powder mixture has a problem that the raw material mixture causes segregation. Speaking of segregation, since the powder mixture contains powders having different particle diameters, particle shapes and particle densities, segregation easily occurs during transportation after mixing, charging into a hopper, discharging, or a molding process. Will occur.

For example, a mixture of iron-based powder and graphite powder is
It is well known that vibration during truck transportation causes segregation in the transportation container and floats graphite powder. It is also known that the graphite charged in the hopper is segregated in the hopper, and therefore, when discharged from the hopper, the concentration of the graphite powder is different in the initial, middle, and final discharging stages.

Due to these segregations, the products have variations in composition, and dimensional changes and variations in strength increase, which causes defective products. Further, since graphite powder and the like are all fine powders, the specific surface area of the mixture is increased, and as a result, the fluidity is reduced. Such a decrease in fluidity also reduces the filling rate into the molding die, which also has the drawback of reducing the production rate of the green compact.

As a technique for preventing the segregation of such powder mixture, Japanese Patent Laid-Open Nos. 56-136901 and 58-28321 are available.
Although there is a technique of using a binder as disclosed in Japanese Patent Publication, there is a problem that if the addition amount of the binder is increased so as to sufficiently improve the segregation of the powder mixture, the fluidity of the powder mixture is lowered. . In addition, the present inventors have previously described in Japanese Patent Laid-Open No.
In Japanese Patent No. 5701 and Japanese Unexamined Patent Publication No. 47201/1990, a method of using a metal soap or a co-melt of wax and oil as a binder was proposed.

These techniques are capable of significantly reducing segregation and dust generation of the powder mixture and improving the fluidity. However, these methods have a problem that the fluidity of the powder mixture changes with time due to the above-mentioned means for preventing segregation. Therefore, the present inventors have further developed a method using a co-melted material of a high melting point oil and a metallic soap as a binder, as proposed in JP-A-2-57602. The technique is one in which the temporal change of the co-melt is small and the change in the fluidity of the powder mixture with time is reduced. However, in this technique, the saturated fatty acid having a high melting point which is solid at room temperature and the metal soap are mixed with the iron-based powder, which causes another problem that the apparent density of the powder mixture changes.

In order to solve this problem, the present inventors disclosed in JP-A-3-162502 that after coating the iron-based powder surface with a fatty acid, an additive was added to the iron-based powder surface with a fatty acid and a metal soap. We proposed a method in which it was attached by a melt and then metal soap was added to the outer surface.

[0011]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Problems such as segregation and dust generation have been considerably solved by the techniques disclosed in Japanese Patent Publication No. Hei 3-162502. However, the fluidity, in particular, the fluidity at the time of heating in so-called warm molding, in which the mixed powder is heated up to about 150 ° C., filled in the same heated mold and then molded, was insufficient.

[0012] JP-A-2-156002, JP-A-7-103404, USP 5, which have improved formability in warm forming.
Also in 256,185 and USP 5,368,630, since the low melting point lubricant component forms a liquid bridge between particles, the fluidity of the metal powder mixed powder during warming is poor. If the fluidity is insufficient, it not only hinders the productivity of the green compact as described above, but also the filling into the mold is not uniform and the density distribution of the green compact varies. As a result, there is a problem that it causes variation in the characteristics of the sintered body, and this solution has been a problem.

The first object of the present invention is not only room temperature,
An object is to provide an iron-based powder for powder metallurgy and a method for producing the same, which has excellent fluidity even in a warm state. As mentioned above
The warm compaction technology disclosed in, for example, 2-156002 publication is a method for producing a high-density and high-strength iron-based powder compact, but has the drawback of high ejection force during compaction, and There were problems such as scratches and shortened life of the mold.

A second object of the present invention is to provide an iron-based powder mixed powder for powder metallurgy and a method for producing the same, which is capable of reducing the ejection force during molding at room temperature and warm temperature and has improved moldability. .

[0015]

First of all, in order to solve the first problem, the present inventors have found that the fluidity of a metal powder mixed with an organic compound such as a lubricant is extremely higher than that of an unmixed metal powder. I researched the cause of getting worse. As a result, it was found that the frictional resistance and the adhesive force between the metal powder and the organic compound were large, and various measures were taken to reduce the frictional resistance and the adhesive force between them.

As a result, if the surface of the metal powder particles is surface-treated (coated) with a certain organic compound which is stable up to a high temperature region (about 200 ° C.), the friction resistance is reduced, and further, the surface of the metal powder particles is reduced. By bringing the surface potential close to the surface potential of the organic compound (excluding the surface treatment agent), it was found that contact charging between different kinds of particles during mixing was suppressed and adhesion between particles due to electrostatic force was prevented.

In order to improve the moldability, which is the second problem, the effects of various solid lubricants are grasped, and at room temperature and warm temperature, an inorganic or organic compound having a layered crystal structure, It was found that a thermoplastic resin or an elastomer that plastically deforms at a temperature of 100 ° C or higher at a low temperature reduces the ejection force during molding and improves the moldability. Furthermore, by the above surface treatment applied to improve the fluidity,
It has been found that coating the surface of the metal powder also has the effect of secondarily reducing ejection force during molding and improving moldability.

That is, the first invention is an iron-based powder mixture containing an iron-based powder, a lubricant and an alloying powder, and at least one selected from the iron-based powder, the lubricant and the alloying powder is a surface treatment agent. An iron-based powder mixture for powder metallurgy having excellent fluidity and moldability, which is a powder coated with. A second invention is an iron-based powder mixture containing an iron-based powder, a lubricant and an alloying powder,
Least one lubricant and selected from the alloy powder is, Ol
Ganoalkoxysilane, organosilazane, silicone
Oil, titanate coupling agent, fluorine cup
One or more selected from ring agents or alkylbenzenes
It is coated with the above surface treatment agent, contains at least graphite powder as the alloy powder, contains at least metal soap and fatty acid amide as the lubricant, and has a graphite powder content of 0.05 to 1 wt% and a fatty acid amide content. 0.01-1.
The iron-based powder mixture for powder metallurgy is excellent in fluidity and moldability, characterized in that the content of metal soap is 0.01 to 1.0 wt%.

Examples of the iron-based powder in the present invention include pure iron powder such as atomized iron powder or reduced iron powder, or partially diffused alloyed steel powder or fully alloyed steel powder .

Organoalkoxysilane means R _4-m-
Si (OC _n H _{2n + 1} ) _m [R is an organic group, n and m are integers,
R is a substance having a structure of m = 1 to 3), and R may or may not have a substituent, but in the present invention, an unsubstituted substance is more preferable. The above-mentioned substituent is more preferably one or more selected from organoalkoxysilanes which are an acrylic group, an epoxy group or an amino group.

The organosilazane has the general formula R _n Si
(NH ₂ ) _4-n , (R ₃ Si) ₂ NH, R ₃ SiNH (R ₂ SiNH) _n SiR ₃ , (R ₂ SiN
Examples thereof include organosilazanes represented by H) _n and R ₃ SiNH (R ₂ SiNH) _n SiR ₃ . Before SL first aspect, in the second invention, the lubricant is an inorganic compound having a layered crystal structure, organic compounds having a layered crystal structure, thermoplastic resins, thermoplastic elastomers, fatty acid amides and metal soaps It is preferably at least one selected from

The inorganic compound having a layered crystal structure is preferably one or more selected from graphite, fluorocarbon and MoS _2, and the organic compound having a layered crystal structure is melamine-cyanuric acid. Addition compounds (MCA) or N-alkylaspartic acid-β-alkyl esters are preferred. The thermoplastic resin is preferably one or more selected from powdery polystyrene, nylon, polyethylene and fluororesin having a particle size of 30 μm or less.

The thermoplastic elastomer is preferably a powdery thermoplastic elastomer having a particle size of 30 μm or less. Furthermore, it is more preferable that the thermoplastic elastomer is one or more selected from styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, amide-based thermoplastic elastomers, and silicone-based thermoplastic elastomers.

The fatty acid amide is preferably one or more selected from fatty acid monoamide and fatty acid bisamide. Further, in the first invention and the second invention, it is more preferable that at least graphite is contained as the lubricant. The iron-based powder mixture of the first invention and the second invention described above can be manufactured by the manufacturing methods of the third invention to the sixth invention shown below.

That is, the third invention is a method for producing an iron-based powder mixture for powder metallurgy, which is particularly excellent in fluidity, and at least one of the constituents thereof is an organoalcohol.
Xysilane, organosilazane, silicone oil, chi
Tanate coupling agent, Fluorine coupling agent,
Or at least one selected from the group of alkylbenzenes
The iron-based powder and the alloy powder coated with the surface treatment agent are fatty acids, fatty acid amides , thermoplastic resins, thermoplastic elastomers, inorganic compounds having a layered crystal structure and organic compounds having a layered crystal structure. A step of adding one or more kinds selected from among lubricants or a metal soap and performing primary mixing, while heating the mixture after the primary mixing to a melting point of at least one kind of the lubricants mentioned above or higher. A step of stirring and melting the lubricant, cooling the mixture obtained after the melting step while mixing, and fixing the alloy powder to the surface of the iron-based powder with the lubricant, obtained in the step In addition to the mixture containing the iron-based powder to which the powder for alloying is fixed, further has a metallic soap, a thermoplastic resin, a fatty acid amide, a thermoplastic elastomer, and a layered crystal structure. An iron base for powder metallurgy excellent in fluidity and moldability, which comprises a step of adding one or more kinds selected from an inorganic compound powder and an organic compound powder having a layered crystal structure and secondary mixing It is a manufacturing method of a powder mixture.

Further, in the present invention, the production of an iron-based powder mixture for powder metallurgy excellent in fluidity and moldability is carried out by the following fourth invention in which a fatty acid amide is essential as the lubricant in the third invention. It has become possible. At least one of the fourth inventions is an organoalkoxysila.
, Organosilazane, silicone oil, titanate
Coupling agent, Fluorine coupling agent and Al
Iron- based powders and alloy powders coated with one or more surface-treating agents selected from killbenzene , (1) fatty acid amide and (2) metal soap, thermoplastic resin having a higher melting point than the fatty acid amide, A step of adding at least one selected from a thermoplastic elastomer, an inorganic compound having a layered crystal structure, and a lubricant that is an organic compound having a layered crystal structure, and performing primary mixing, and obtained by the primary mixing step. The mixture is stirred while heating above the melting point of the fatty acid amide, the step of melting the fatty acid amide, the mixture obtained after the melting step is cooled while mixing, the surface of the iron-based powder with the lubricant. The step of fixing the alloying powder, the mixture containing the iron-based powder to which the alloying powder obtained in the step is fixed, are further mixed with a metal soap, a thermoplastic resin, and a fatty acid And a thermoplastic elastomer, an inorganic compound powder having a layered crystal structure, and an organic compound powder having a layered crystal structure, and a secondary mixing step. It is a method for producing an iron-based powder mixture for powder metallurgy, which is excellent in moldability and moldability.

Further in accordance with the present invention, the third invention,
The surface treatment in the fourth invention may be performed after the primary mixing described above. That is, a fifth aspect of the present invention provides an iron-based powder and an alloy powder with fatty acids, fatty acid amides , thermoplastic resins, thermoplastic elastomers, inorganic compounds having a layered crystal structure, and organic compounds having a layered crystal structure. One or more selected from compound lubricants or
A step of adding a metal soap to them and performing primary mixing; stirring the mixture obtained in the primary mixing step while heating the mixture to a melting point of at least one of the above-mentioned lubricants or higher, The step of melting the agent, cooling the mixture obtained in the melting step while mixing, and in the temperature range of 100 to 140 ° C. during the cooling process, the organoalkoxysilane, the organosilazane, the
Silicone oil, titanate coupling agent, fluorine
System coupling agent and alkylbenzene
A step of adding and mixing one or more surface-treating agents, and a mixture having the surface-treating agents added and mixed in the step, further having a metal soap, a thermoplastic resin, a fatty acid amide, a thermoplastic elastomer, and a layered crystal structure An iron base for powder metallurgy excellent in fluidity and moldability, which comprises a step of adding one or more kinds selected from an inorganic compound powder and an organic compound powder having a layered crystal structure and secondary mixing It is a manufacturing method of a powder mixture.

Further, in the present invention, the production of an iron-based powder mixture for powder metallurgy excellent in fluidity and moldability is carried out by the following sixth invention in which a fatty acid amide is essential as the lubricant in the fifth invention. It has become possible. That is, a sixth aspect of the present invention provides an iron-based powder and a powder for alloys according to (1)
Fatty acid amide and (2) metal soap, thermoplastic resin, thermoplastic elastomer having a higher melting point than the fatty acid amide,
1 selected from an inorganic compound having a layered crystal structure and a lubricant that is an organic compound having a layered crystal structure
A step of adding at least one species and performing primary mixing; a step of stirring the mixture obtained in the primary mixing step at a temperature equal to or higher than the melting point of the fatty acid amide to melt the fatty acid amide; Organo in the temperature range of 100 to 140 ° C
Alkoxysilane, organosilazane, silicone oil
, Titanate coupling agent, fluorine coupling
At least one selected from the group
That mixing added surface treatment agent, to the mixture surface treatment agent obtained was added in about該工, further inorganic compounds having metallic soap, thermoplastic resin, fatty acid amides, thermoplastic elastomers, a layered crystal structure A powder and an iron-based powder mixture for powder metallurgy excellent in fluidity and moldability, which comprises a step of adding at least one selected from powders and organic compound powders having a layered crystal structure and secondary mixing Is a manufacturing method.

The strength of the sintered body can be increased by including at least graphite powder, copper powder or cuprous oxide powder in the alloy powder contained in the iron-based powder mixture of the present invention.

By using, as a lubricant contained in the iron-based powder mixture of the present invention, a co-melt of fatty acid amide and metal soap, or two or more waxes having different melting points, or a partial melt of fatty acid amide, The segregation and dust generation of the iron-based powder mixture are effectively prevented, and the fluidity and moldability are further improved. As the fatty acid amide, ethylene stearic acid bisamide is particularly preferable.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. The present invention is an iron-based powder mixture containing an iron-based powder, a lubricant, and an alloying powder, wherein at least one selected from the iron-based powder, the lubricant and the alloying powder is composed of a powder coated with a surface treatment agent. It is an iron-based powder mixture for powder metallurgy having excellent fluidity and moldability. In the present invention
The surface treatment agent is an organoalkoxysilane, an organo
Nosilazane, silicone oil, titanate type coupling
Agent, fluorine-based coupling agent and alkylbenze
One or more selected from the following .

Examples of the iron-based powder in the present invention include pure iron powder such as atomized iron powder or reduced iron powder, partially diffused alloyed steel powder, fully alloyed steel powder, or a mixed powder thereof. . The addition rate of the surface treatment agent of the present invention and the content rates of the lubricant and the alloy powder described above in the iron-based powder mixture are preferably in the following ranges.

The addition rate of the surface treatment agent is 100 wt% of the treated powder.
On the other hand, 0.001 to 1.0 wt% is preferable. 0.
If it is less than 001 wt%, the fluidity will decrease, and if it exceeds 1.0 wt%, the fluidity will decrease. The total content of the lubricant is preferably 0.1 to 2.0 wt% with respect to 100 wt% of the iron-based powder.

If it is less than 0.1 wt%, the moldability will decrease,
If it exceeds 2.0 wt%, the green compact density will decrease and the green compact strength will decrease. Content of alloy powder is 100 wt% of iron-based powder
Is preferably 0.1 to 10 wt%. this is,
This is because the strength of the obtained sintered body is excellent by containing 0.1 wt% or more of graphite powder, metal powder such as Cu, Mo, Ni, etc., and alloy powder such as B powder, and conversely, if it exceeds 10 wt%. This is because the dimensional accuracy of the sintered body is reduced.

Further, the iron-based powder mixture of the present invention, as part or all of the lubricant is selected from one or more or even a metal soap selected from fatty acid amide 1
It is preferable to contain one or more species . The content of the metal soap is preferably 0.01 to 1.0 with respect to 100 wt% of the iron-based powder in the iron-based powder mixture, a metal soap selected from zinc stearate, lithium stearate, lithium hydroxystearate, calcium laurate and the like. It is more preferable to include it at a content rate of wt%.

This is because the fluidity is improved by containing the metal soap in an amount of 0.01 wt% or more, and conversely, when it exceeds 1.0 wt%, the strength of the green compact is reduced. The content of the fatty acid amide is preferably 0.01 to 1.0 wt% with respect to 100 wt% of the iron-based powder in the fatty acid amide selected from fatty acid monoamide and fatty acid bisamide.

This is because if the fatty acid amide is contained in an amount of 0.01 wt% or more, the moldability is improved, and conversely, if it exceeds 1.0 wt%, the density of the green compact is reduced. Hereinafter, the reason why the effects of the above-described configuration of the present invention are exhibited will be described. As described above, the fluidity of the metal powder mixed with an organic compound such as a lubricant is extremely worse than that of the metal powder not mixed.

This is because the frictional resistance and adhesive force between the metal powder and the organic compound are large, and the frictional resistance is reduced by surface-treating (coating) the surface of the metal powder with a certain organic compound. , The surface potential of the surface of the metal powder is brought close to the surface potential of the organic compound (excluding the above-mentioned surface treatment agent) to suppress contact charging between different particles during mixing, thereby preventing interparticle adhesion due to electrostatic force, The fluidity of the mixed powder can be improved by the combined effect. In particular, it is possible to secure stable fluidity from room temperature to a temperature range of about 200 ° C. so as to be compatible with warm forming.

Next, organoalkoxysilane, organosilazane, silicone oil, titanate coupling agent, fluorine coupling agent or alkylbenze.
The reason why the fluidity is improved over a wide temperature range by coating the surface of the iron-based powder with iron is described in more detail. The organic group of the organoalkoxysilane may or may not have a substituent.

The surface treatment agent has a lubricating function due to its bulky molecular structure and is stable in a high temperature range as compared with fatty acids and mineral oils, and therefore exhibits a lubricating function in a wide temperature range from room temperature to about 200 ° C. . In particular, organoalkoxysilanes, organosilazanes, and titanate-based or fluorine-based coupling agents are organic compounds on the surface of metal powder particles due to a condensation reaction between a hydroxyl group present on the surface of the metal powder and the surface treatment agent molecule and a predetermined functional group. Since the compound is chemically bonded to perform surface modification, it does not peel off or flow from the particle surface even at high temperature, and the surface modification effect at high temperature is remarkable.

The organoalkoxysilane may have an unsubstituted organic group, and the substituent of the organic group may be any of an acryl group, an epoxy group and an amino group, but an unsubstituted group is particularly preferable. These can be used as a mixture of different kinds, but those having an epoxy group and those having an amide group react with each other and change in quality, so they are not suitable for mixing.

[0042] The number of alkoxy groups _{(C n H 2n + 1 O-} ) in the organoalkoxysilane, the smaller is preferred. Examples of the non-substituted organic group include methyltrimethoxysilane, phenyltrimethoxysilane, and diphenyldimethoxysilane. Further, as the substituent of the organic group is an acrylic group, γ-methacryloxypropyltrimethoxysilane, as an epoxy group,
As the γ-glycidoxypropyltrimethoxysilane and the amino group, N-β (aminoethyl) γ-aminopropyltrimethoxysilane and the like can be used.

In the above organoalkoxysilane, it is also possible to use a so-called fluorine-based coupling agent in which a part of hydrogen in the organic group is replaced with fluorine. Isopropyltriisostearoyl titanate can be used as the titanate coupling agent. As the organosilazane, an alkylsilazane is preferable, and a polyorganosilazane having a large molecular weight can also be used.

Silicone oil as a surface treatment agent and
The reason why alkylbenzene is preferable is as follows. Silicone oil and alkylbenze as surface treatment agents
The reason why it is preferable is that when the powder particles are bulky and adsorbed on the surface of the powder particles, the frictional resistance between the particles is reduced to improve the fluidity, and the thermal stability has a lubricating effect in a wide temperature range.

As the silicone oil which can be used as the surface treatment agent, dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, cyclic polymethylsiloxane, alkyl modified silicone oil, amino modified silicone oil, silicone polyether copolymer Coalesced, fatty acid modified silicone oil,
Epoxy-modified silicone oil, fluorosilicone oil
Is exemplified .

In an iron-based powder mixture whose fluidity is stable over a wide temperature range from room temperature to about 200 ° C., the organic compound (so-called lubricant, etc.) that fixes the iron-based powder and the alloying powder have different melting points. It is preferably a partial melt of two or more waxes, especially an amide lubricant. The method of using a co-melted product of a fatty acid and a metal soap disclosed by the present inventors in JP-A-3-162502 is a method in which a melt coats the entire additive particles by a capillary phenomenon in a co-melted state to form an iron-based powder. It is most suitable because it adheres firmly to. Partial melts of two or more waxes having different melting points or amide lubricants are also preferable for the same reason.

Next, the reason why the ejection force at the time of molding is reduced and the moldability is improved by mixing the inorganic or organic compound having a layered crystal structure with the iron-based powder and the powder for alloy will be described. Regarding the lubricating action of the compound having a layered crystal structure, in the case of the present invention, the above-mentioned substance subjected to shear stress during molding is likely to cleave along the crystal plane, and therefore the friction resistance between particles inside the molded body is increased. Reduction of
Alternatively, it is considered that slippage between the molded body and the mold is caused.

The inorganic compound having a layered crystal structure may be any of graphite, MoS ₂ and fluorocarbon. The finer the particle size, the more effective the reduction of the ejection force. As the organic compound having a layered crystal structure, a melamine-cyanuric acid addition compound (MCA) or an N-alkylaspartic acid-β-alkyl ester can be used.

The reason why the ejection force during molding, especially during warm molding, is reduced by mixing the thermoplastic resin or the thermoplastic elastomer with the iron-based powder and the alloy powder will be described. A characteristic of the thermoplastic resin is that the yield stress decreases as the temperature rises and is easily deformed by lower pressure. In the warm molding in which the particulate thermoplastic resin is mixed with the metal powder and molded while being heated, the thermoplastic resin particles are
Plastic deformation easily occurs between the metal particles or between the metal particles and the mold wall surface, and as a result, the frictional resistance between the metal surfaces is reduced.

The thermoplastic elastomer is a material having a mixed phase structure of a thermoplastic resin (hard phase) and a polymer having a rubber structure (soft phase), and the yield of the thermoplastic resin which is the hard phase as the temperature rises. The stress is reduced and it easily deforms at lower stress. Therefore, the effect when the particulate thermoplastic elastomer is mixed with the metal particles and subjected to warm molding is similar to that of the above-mentioned thermoplastic resin.

As the thermoplastic resin, particles of polystyrene, nylon, polyethylene or fluororesin are suitable. As a thermoplastic elastomer, as a hard phase,
Styrene resin, olefin resin, amide resin or silicone resin is preferred, especially styrene-acrylic,
Styrene-butadiene polymers are good.

The particle size of the thermoplastic resin or thermoplastic elastomer is preferably 30 μm or less, and more preferably 5 to 20 μm. If it exceeds 30 μm,
This is because the resin or elastomer particles are not sufficiently dispersed between the metal particles and the lubricating effect is not exhibited. The effect of improving the fluidity of the surface treating agent and the effect of improving the moldability of the lubricant in the present invention have been described above. Since a secondary effect of reducing the output has been found, its mechanism will be described.

In high-density molding such as warm molding, since the density of the molded body increases, the metal powder on the surface of the molded body is often pressed against the wall surface of the mold during molding, which increases the ejection force when the molded body is ejected. It may cause scratches on the molded product. On the other hand, when the surface of the metal powder is previously coated with the above-mentioned surface treatment agent, a coating film is present between the metal powder on the wall surface of the mold and the metal powder on the surface of the molded body during molding. It is considered that the above-mentioned problems can be prevented, the ejection force can be reduced, and that problems such as scratches on the molded product can be solved.

As a specific method for producing the iron-based powder mixture for powder metallurgy of the present invention, it is preferable to use the method exemplified in the following examples.

[0055]

[Example 1]

Various organoalkoxysilanes, organosilazanes, titanate-based or fluorine-based coupling agents in ethanol, silicone oil or alkyl benzene.
Zen was dissolved in xylene and sprayed onto iron powder for powder metallurgy having an average particle size of 78 μm, natural graphite having an average particle size of 23 μm or less, or copper powder having an average particle size of 25 μm or less.

Each of the obtained powders was mixed with a high-speed mixer for 1 minute under the condition of stirring blade rotation speed: 1000 rpm,
The solvent was removed by a vacuum dryer, and the silane, silazane or coupling agent was sprayed at about 100 ° C.
Heated for 1 hour. The above process is referred to as a preliminary process A1.
Table 1 shows the types and amounts of the surface treatment agents added in the pretreatment A1.

The contents of the symbols described in the column of surface treatment agent in Table 1 are as shown in Table 14. Iron powder for powder metallurgy having an average particle size of 78 μm, which has been subjected to the pretreatment A1 or not, and natural graphite having an average particle size of 23 μm or less, which has been subjected to the pretreatment A1 or not subjected to the pretreatment A1 A copper powder having an average particle size of 25 μm or less, which has been subjected to the pretreatment A1 or not subjected to the pretreatment A1, is mixed, and 0.2% by weight of ethylene stearic acid monoamide and 0.2% by weight of ethylene stearic acid bisamide are added and mixed at 110 ° C.
The mixture was heated at 85 ° C. and further cooled to 85 ° C. or lower while mixing.

Ethylene stearic acid monoamide 0.2% by weight, zinc stearate 0.
15% by weight was added, and after uniformly stirring and mixing, the mixture was discharged from the mixer (Invention Examples 1 to 11). For comparison, the above pretreatment A
Iron powder for powder metallurgy having an average particle size of 78 μm, natural graphite having an average particle size of 23 μm or less, and copper powder having an average particle size of 25 μm or less were subjected to the same treatment as above to obtain a powder mixture ( Comparative example 1).

Next, 100 g of each of the obtained powder mixtures was discharged from an orifice having a discharge hole diameter of 5 mmΦ at room temperature,
The time until the end of discharge (fluidity) was measured to examine the fluidity. The experimental results are shown in Table 1. As is clear from the comparison between Comparative Example 1 and Invention Examples 1 to 11 shown in Table 1, when the treatment with the surface treating agent is performed, the fluidity of the mixed powder is remarkably improved.

[0060]

[Table 1]

Example 2 An iron powder for powder metallurgy having an average particle size of 78 μm, natural graphite having an average particle size of 23 μm or less, and copper powder having an average particle size of 25 μm or less were mixed, and various organoalkoxysilanes, organosilazanes or titanate-based materials were mixed. Alternatively, an appropriate amount of a fluorine-based coupling agent, silicone oil, or alkylbenzene was sprayed.

Each of the powder mixtures coated with the different surface treatment agents described above was stirred with a high-speed mixer at a rotating speed of a stirring blade:
After mixing for 1 minute at 1000 rpm, add oleic acid 0.1
% By weight and 0.3% by weight of zinc stearate were added, and the mixture was heated at 110.degree. C. with mixing and then cooled to 85.degree. The above processing is referred to as preliminary processing B1.

Table 2 shows the types and amounts of the surface treatment agents added in the pretreatment B1. The contents of the symbols described in the column of surface treatment agent in Table 2 are as shown in Table 14. 0.4% by weight of zinc stearate was added to each of the obtained powder mixtures, and the mixture was uniformly stirred and mixed, and then discharged from the mixer (Invention Examples 12 to 17). For comparison, iron powder for powder metallurgy with an average particle size of 78 μm, natural graphite with an average particle size of 23 μm or less, and copper powder with an average particle size of 25 μm or less are mixed, and no surface treatment agent is added in the pretreatment B1. In the same manner as above, a powder mixture was obtained (Comparative Example 2).

Next, 100 g of each obtained powder mixture was discharged from an orifice having a discharge hole diameter of 5 mmΦ at room temperature,
The time until the end of discharge was measured, and the fluidity was examined as in Example 1. The experimental results are shown in Table 2. Comparative Example 2 shown in Table 2
As is clear from the comparison between Invention Examples 12 to 17, the fluidity of the mixed powder is remarkably improved when the treatment with the surface treatment agent is performed.

[0065]

[Table 2]

Example 3 Iron powder for powder metallurgy having an average particle size of 78 μm, natural graphite having an average particle size of 23 μm or less, copper powder having an average particle size of 25 μm or less, ethylene stearate monoamide 0.2% by weight, ethylene stearate bisamide Add 0.2 wt% and mix with mixing at 110 ° C
After heating in, various organoalkoxysilanes, organosilazanes, titanates or fluorine coupling agents, silicone oils or alkyls.
A proper amount of benzene was sprayed.

Each of the powder mixtures coated with the various surface treatment agents described above was subjected to a high-speed mixer with a stirring blade rotation speed:
After mixing for 1 minute at 1000 rpm, the mixture was cooled to 85 ° C or lower. The above process is referred to as a preliminary process C1. Pretreatment C1
Table 3 shows the types and the amounts of the surface treatment agents added in step 3.

The contents of the symbols shown in the surface treatment agent column in Table 3 are as shown in Table 14. To the obtained powder mixture, 0.2% by weight of ethylene stearic acid monoamide and 0.15% by weight of zinc stearate were added, uniformly stirred and mixed, and then discharged from the mixer (Invention Examples 18 to 22). For comparison, iron powder for powder metallurgy with an average particle size of 78 μm, average particle size of 23 μm
Using the following natural graphite and copper powder having an average particle size of 25 μm or less, the same treatment was carried out in the pretreatment C1 without adding a surface treatment agent to obtain a powder mixed powder (Comparative Example 3). .

Next, 100 g of each obtained powder mixture was discharged from an orifice having a discharge hole diameter of 5 mmΦ at room temperature,
The time until the end of discharge was measured, and the fluidity was examined as in Example 1. The experimental results are shown in Table 3. Comparative Example 3 shown in Table 3
As is clear from a comparison of Invention Examples 18 to 22, the fluidity of the mixed powder is remarkably improved when the treatment with the surface treatment agent is performed.

[0070]

[Table 3]

Example 4 Various organoalkoxysilanes, organosilazanes, titanate-based or fluorine-based coupling agents were added to ethanol, and silicone oil or alkyl benzene was used.
Zen is dissolved in xylene, and the average particle size is approximately 80 μm.
An appropriate amount was sprayed on the alloy steel powder for powder metallurgy (completely alloyed steel powder) or natural graphite having an average particle size of 23 μm or less.

The obtained powders were mixed with a high-speed mixer for 1 minute under the condition of stirring blade rotation speed: 1000 rpm.
The solvent was removed by a vacuum dryer, and the silane, silazane or coupling agent was sprayed at about 100 ° C.
Heated for 1 hour. The above processing is referred to as preliminary processing A2.
Table 4 shows the types and the amounts of the surface treatment agents added in the pretreatment A2.

The contents of the symbols described in the surface treatment agent column in Table 4 are as shown in Table 14. Average particle size of about 80μm with or without pretreatment A2
Alloy steel powder for powder metallurgy and natural graphite with an average particle size of 23 μm or less, which is pretreated A2 or not pretreated A2, are mixed, and ethylene stearate monoamide 0.1 wt% and ethylene stearate bisamide 0.2 wt% are mixed. , While adding 0.1% by weight of lithium stearate and mixing
It was heated at 160 ° C and cooled to below 85 ° C with further mixing.

Lithium stearate (0.4% by weight) was added to each of the obtained powder mixtures, and the mixture was stirred and mixed uniformly and discharged from the mixer (Invention Examples 23 to 26). For comparison, the above treatment was similarly carried out using the alloy steel powder for powder metallurgy having an average particle diameter of about 80 μm and natural graphite having an average particle diameter of 23 μm or less without performing the pretreatment A2 to obtain a powder mixture ( Comparative example 4).

Next, 100 g of each of the obtained powder mixtures was added to 20
After heating to a predetermined temperature of ~ 140 ℃, discharge from the orifice with discharge hole diameter 5mmΦ, and measure the time until discharge is completed.
The fluidity was examined in the same manner as in Example 1. The experimental results are shown in Table 4. As is clear from the comparison between Comparative Example 4 and Inventive Examples 23 to 26 shown in Table 4, when the treatment with the surface treatment agent is performed, the fluidity of the mixed powder is remarkably improved.

[0076]

[Table 4]

Example 5 Partial diffusion alloyed steel powder for powder metallurgy having an average particle size of about 80 μm and natural graphite having an average particle size of 23 μm or less are mixed, and various organoalkoxysilanes, organosilazanes, titanate-based or fluorine-based cups are mixed. A proper amount of ring agent, silicone oil or alkylbenzene was sprayed.

Each of the powders coated with the various surface treatment agents described above was stirred with a high speed mixer at a rotating speed of a stirring blade of 1000 rpm.
After mixing for 1 minute under the following conditions, ethylene stearate monoamide 0.2% by weight, ethylene stearate bisamide
0.2% by weight was added and the mixture was heated at 160 ° C with mixing and then cooled to below 85 ° C. The above process is referred to as a preliminary process B2.

Table 5 shows the types and amounts of the surface treatment agents added in the pretreatment B2. The contents of the symbols described in the column of the surface treatment agent in Table 5 are as shown in Table 14. Lithium hydroxystearate was added to the obtained powder mixture.
0.4% by weight was added, and after uniformly stirring and mixing, the mixture was discharged from the mixer (Invention Examples 28 to 31). For comparison, average particle size of about 80
μm partially diffused alloyed steel powder for powder metallurgy, average particle size 23 μm
The following natural graphite was mixed, and the same treatment was carried out in the pretreatment B2 without adding the surface treatment agent to obtain a powder mixture (Comparative Example 5).

Next, 100 g of the obtained powder mixture was added to 20-
After heating to a predetermined temperature of 140 ° C., the liquid was discharged from an orifice having a discharge hole diameter of 5 mmΦ, the time until the completion of discharge was measured, and the fluidity was examined as in Example 1. The experimental results are shown in Table 5. As is clear from the comparison between Comparative Example 5 and Invention Examples 28 to 31 shown in Table 5, the fluidity of the mixed powder is remarkably improved when the treatment with the surface treatment agent is performed.

[0081]

[Table 5]

Example 6 A partially diffusion alloyed steel powder for powder metallurgy having an average particle size of about 80 μm and natural graphite having an average particle size of 23 μm or less were mixed, and 0.2% by weight of ethylene stearic acid monoamide and 0.2% by weight of ethylene stearic acid bisamide were mixed. %, Added and heated at 160 ° C. with mixing, then cooled to about 110 ° C.

Various amounts of various organoalkoxysilanes, organosilazanes, titanate-based or fluorine-based coupling agents, silicone oil or alkylbenzene were sprayed onto the obtained powder mixture. Each powder mixture coated with the various surface treatment agents described above was mixed with a high-speed mixer under the condition of stirring blade rotation speed: 1000 rpm,
After mixing for 1 minute, the mixture was cooled to 85 ° C or lower.

The above processing is referred to as preliminary processing C2. Table 6 shows the types and amounts of the surface treatment agents added in the pretreatment C2.
Shown in. The contents of the symbols described in the surface treatment agent column in Table 6 are as shown in Table 14. To each powder mixture obtained, 0.4% by weight of lithium hydroxystearate was added, uniformly stirred and mixed, and then discharged from the mixer (Invention Example 32).
~ 34).

Next, 100 g of the obtained powder mixture was added to 20-
After heating to a predetermined temperature of 140 ° C., the liquid was discharged from an orifice having a discharge hole diameter of 5 mmΦ, the time until the completion of discharge was measured, and the fluidity was examined as in Example 1. The experimental results are shown in Table 6. As is clear from the comparison between Comparative Example 5 and Invention Examples 32 to 34 shown in Tables 5 and 6, when the treatment with the surface treatment agent is performed,
The fluidity of the mixed powder is remarkably improved.

[0086]

[Table 6]

Example 7 Various organoalkoxysilanes, organosilazanes, titanate-based or fluorine-based coupling agents were added to ethanol, and silicone oil or alkyl benzene was used.
Zen is dissolved in xylene, and the average particle size is approximately 80 μm.
Partially diffused alloyed steel powder for powder metallurgy, or average particle size 23μ
A proper amount of m or less natural graphite was sprayed.

Each of the obtained powders was mixed with a high-speed mixer for 1 minute under the condition of stirring blade rotation speed: 1000 rpm.
The solvent was removed by a vacuum dryer, and the silane, silazane or coupling agent was sprayed at about 100 ° C.
Heated for 1 hour. The above processing is called preliminary processing A2.
Table 7 shows the types and the amounts of the surface treatment agents added in the pretreatment A2.

The contents of the symbols shown in the surface treatment agent column in Table 7 are as shown in Table 14. Average particle size of about 80μm with or without pretreatment A2
Alloy steel powder for powder metallurgy and natural graphite with an average particle size of 23 μm or less, which is pretreated A2 or not pretreated A2, are mixed, and ethylene stearate monoamide 0.1 wt% and ethylene stearate bisamide 0.2 wt% are mixed. , And, in addition, either a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure.
0.1% by weight was added, the mixture was heated at 160 ° C. while being mixed, and further cooled to 85 ° C. or lower while being mixed to obtain a powder mixture.

Added lubricant (thermoplastic resin or thermoplastic elastomer or compound having layered crystal structure)
Table 7 shows the types and addition amounts. The contents of the symbols described in the column of lubricant in Table 7 are as shown in Table 15. In addition,
For comparison, the average particle size without the pretreatment A2 is about
80μm partially diffused alloyed steel powder for powder metallurgy, average particle size 23μ
Natural graphite of m or less was mixed, and the above treatment was similarly performed without adding the lubricant to obtain a powder mixture.

Next, at least one of lithium stearate, lithium hydroxystearate or calcium laurate was added to the obtained powder mixture in a total amount of 0.2% by weight, and after uniformly stirring and mixing, the mixture was discharged from the mixer. (Invention Examples 35 to 39, Comparative Example 6). Next, 100 g of the obtained powder mixture was heated to a predetermined temperature of 20 to 140 ° C., then discharged from an orifice having a discharge hole diameter of 5 mmΦ, and the time until the end of discharge was measured. I checked.

Further, in parallel with the above liquidity survey,
The powder mixture discharged from the above mixer was molded into a tablet of 11 mmΦ with a molding pressure of 7 ton / cm ² while heating at 150 ° C., and the ejection force and the green compact density during molding were measured. The experimental results are shown in Table 7. Comparative Example 6 and Invention Examples 35 to 39 shown in Table 7
As is clear from the comparison of the above, when the treatment with the surface treatment agent is performed, the fluidity of the mixed powder at each temperature is significantly improved.

Further, as is clear from the comparison between Comparative Example 6 and Invention Examples 35 to 39, a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure was added, and a treatment with a surface treating agent was carried out. In this case, the green compact density is improved, the ejection force is reduced, and the moldability is improved.

[0094]

[Table 7]

[0095]

[Table 8]

Example 8 Partial diffusion alloyed steel powder for powder metallurgy having an average particle size of about 80 μm and natural graphite having an average particle size of 23 μm or less are mixed, and various organoalkoxysilanes, organosilazanes, titanate-based or fluorine-based cups are mixed. A proper amount of ring agent, silicone oil or alkylbenzene was sprayed.

Each of the various powder mixtures obtained was mixed with a high-speed mixer for 1 minute under the condition of the stirring blade rotation speed: 1000 rpm, and then ethylene stearate monoamide 0.2% by weight,
0.2% by weight of ethylene stearic acid bisamide, and
In addition, 0.1% by weight of either a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure was added, the mixture was heated at 160 ° C. while being mixed, and further cooled to 85 ° C. or lower while being mixed.

The above processing is referred to as preliminary processing B2. Table 8 shows the types and addition amounts of the surface treatment agent and the lubricant (thermoplastic resin or thermoplastic elastomer or compound having a layered crystal structure) added in the pretreatment B2. The contents of the symbols shown in the column of surface treatment agent in Table 8 are as shown in Table 14, and the contents of the symbols shown in the column of lubricant are as shown in Table 15.

Next, at least one of lithium stearate, lithium hydroxystearate, and calcium laurate was added to the obtained powder mixture in a total amount of 0.2% by weight, and after uniformly stirring and mixing, the mixture was discharged from the mixer. (Invention Examples 40 to 43). Next, 100 g of the obtained powder mixture was heated to a predetermined temperature of 20 to 140 ° C., then discharged from an orifice having a discharge hole diameter of 5 mmΦ, and the time until the end of discharge was measured. I checked.

Further, in parallel with the above liquidity survey,
The powder mixture discharged from the above mixer was molded into a tablet of 11 mmΦ with a molding pressure of 7 ton / cm ² while heating at 150 ° C., and the ejection force and the green compact density during molding were measured. The experimental results are shown in Table 8. Comparative Example 6 and invention example shown in Table 7 and Table 8
As is clear from the comparison of 40 to 43, the fluidity of the mixed powder at each temperature is remarkably improved when the treatment with the surface treatment agent is performed.

As is clear from the comparison between Comparative Example 6 and Invention Examples 40 to 43, a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure was added, and a treatment with a surface treating agent was applied. In this case, the green compact density is improved, the ejection force is reduced, and the moldability is improved.

[0102]

[Table 9]

Example 9 Partial diffusion alloyed steel powder for powder metallurgy having an average particle size of about 80 μm and natural graphite having an average particle size of 23 μm or less were mixed, and 0.2% by weight of ethylene stearic acid monoamide and 0.2% by weight of ethylene stearic acid bisamide were mixed. %, And, in addition, either a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure.
After adding 1% by weight and heating at 160 ° C while mixing,
It was cooled to about 110 ° C.

To the obtained powder mixture, various kinds of organoalkoxysilane, organosilazane, titanate-based or fluorine-based coupling agent, silicone oil or alkylbenzene was further sprayed in an appropriate amount. Each of the obtained powder mixtures was mixed with a high-speed mixer under the condition of stirring blade rotation speed: 1000 rpm for 1 minute, and then cooled to 85 ° C. or lower.

The above processing is referred to as preliminary processing C2. Table 9 shows the types and amounts of the surface treatment agent and lubricant (thermoplastic resin or thermoplastic elastomer or compound having a layered crystal structure) added in the pretreatment C2. The contents of the symbols described in the column of surface treatment agent in Table 9 are as shown in Table 14, and the contents of the symbols described in the column of lubricant are as shown in Table 15.

Next, 0.4% by weight of lithium hydroxystearate was added to the obtained powder mixture, and the mixture was uniformly stirred and mixed, and then discharged from the mixer (Invention Examples 44 to 48). Next, 100 g of the obtained powder mixture was heated to a predetermined temperature of 20 to 140 ° C., then discharged from an orifice having a discharge hole diameter of 5 mmΦ, and the time until the end of discharge was measured. I checked.

Further, in parallel with the above liquidity survey,
The powder mixture discharged from the above mixer was molded into a tablet of 11 mmΦ with a molding pressure of 7 ton / cm ² while heating at 150 ° C., and the ejection force and the green compact density during molding were measured. The experimental results are shown in Table 9. Comparative Example 6 and invention examples shown in Tables 7 and 9
As is clear from the comparison of 44 to 48, the fluidity of the mixed powder at each temperature is remarkably improved when the treatment with the surface treatment agent is performed.

As is clear from the comparison between Comparative Example 6 and Inventive Examples 44 to 48, a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure was added and a treatment with a surface treating agent was carried out. In this case, the green compact density is improved, the ejection force is reduced, and the moldability is improved.

[0109]

[Table 10]

[0110]

[Table 11]

Example 10 Various organoalkoxysilanes, organosilazanes, titanate-based or fluorine-based coupling agents were placed in ethanol and silicone oil or alkyl benzene was added.
Zen is dissolved in xylene, and the average particle size is approximately 80 μm.
Partially diffused alloyed steel powder for powder metallurgy, or average particle size 23μ
A proper amount of m or less natural graphite was sprayed.

Each of the obtained powders was mixed with a high-speed mixer for 1 minute under the condition of stirring blade rotation speed: 1000 rpm,
The solvent was removed by a vacuum dryer, and the silane, silazane or coupling agent was sprayed at about 100 ° C.
Heated for 1 hour. The above processing is referred to as preliminary processing A2.
Table 10 shows the types and the amounts of the surface treatment agents added in the pretreatment A2.

The contents of the symbols described in the surface treatment agent column in Table 10 are as shown in Table 14. Average particle size of about 80μm with or without pretreatment A2
Alloy steel powder for powder metallurgy and natural graphite with an average particle size of 23 μm or less, which is pretreated A2 or not pretreated A2, are mixed, and ethylene stearate monoamide 0.1 wt% and ethylene stearate bisamide 0.2 wt% are mixed. , And, in addition, either a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure.
0.1 wt.

Lubricants added (thermoplastic resin or thermoplastic elastomer or compound having layered crystal structure)
Table 10 shows the types and addition amounts. The contents of the symbols shown in the lubricant column in Table 10 are as shown in Table 15. next,
To the obtained powder mixture, at least one of lithium stearate, lithium hydroxystearate, and calcium laurate was added in a total amount of 0.2% by weight, uniformly mixed by stirring, and then discharged from the mixer (Invention Example 49). ~ 52).

Next, 100 g of the obtained powder mixture was added to 20-
After heating to a predetermined temperature of 140 ° C., the liquid was discharged from an orifice having a discharge hole diameter of 5 mmΦ, the time until the completion of discharge was measured, and the fluidity was examined as in Example 1. Further, in parallel with the above fluidity investigation, the powder mixture discharged from the above mixer was heated to 150 ° C. and at a molding pressure of 7 ton / cm ²
It was molded into a tablet of mmΦ, and the ejection force and green compact density during molding were measured.

The experimental results are shown in Table 10. As is clear from the comparison between Comparative Example 6 and Inventive Examples 49 to 52 shown in Tables 7 and 10, the fluidity at each temperature of the mixed powder is remarkably improved when the treatment with the surface treatment agent is performed. . Comparative Example 6 and invention example
As is clear from the comparison of 49 to 52, when a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure is added and subjected to a treatment with a surface treatment agent, the green compact density is improved, and The ejection force is reduced and the moldability is improved.

[0117]

[Table 12]

Example 11 Partial diffusion alloyed steel powder for powder metallurgy having an average particle size of about 80 μm and natural graphite having an average particle size of 23 μm or less are mixed, and various organoalkoxysilanes, organosilazanes, titanate-based or fluorine-based cups are mixed. A proper amount of ring agent or silicone oil or alkylbenzene was sprayed.

Each of the obtained powder mixtures was mixed with a high-speed mixer for 1 minute under the condition of stirring blade rotation speed: 1000 rpm, and ethylene stearic acid monoamide was added in an amount of 0.2% by weight.
Add 0.2% by weight of ethylene stearic acid bisamide,
Heat at 160 ° C with mixing, 85 ° C with further mixing
Cooled to: The above process is referred to as a preliminary process B2.

Table 11 shows the types and amounts of the surface treatment agents added in the pretreatment B2. The contents of the symbols described in the surface treatment agent column in Table 11 are as shown in Table 14. Next, to the obtained powder mixture, 0.1% by weight of lithium stearate and, in addition, a lubricant which is at least one of a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure is added in total. The amount was 0.2% by weight, and the mixture was uniformly stirred and mixed, and then discharged from the mixer (Invention Examples 53 to 56).

Table 11 shows the type of lubricant added and the amount added.
Shown in. The contents of the symbols described in the lubricant column in Table 11 are shown in the table.
As shown in 15. Then 100 g of the obtained powder mixture
After heating to a specified temperature of 20 to 140 ° C, the discharge hole diameter is 5 mm.
The liquid was discharged from the orifice of Φ, the time until the discharge was completed was measured, and the fluidity was examined in the same manner as in Example 1.

Further, in parallel with the above liquidity survey,
The powder mixture discharged from the above mixer was molded into a tablet of 11 mmΦ with a molding pressure of 7 ton / cm ² while heating at 150 ° C., and the ejection force and the green compact density during molding were measured. The experimental results are shown in Table 11. Comparative Example 6 and invention examples shown in Table 7 and Table 11
As is clear from the comparison of 53 to 56, the fluidity of the mixed powder at each temperature is remarkably improved when the surface treatment agent is applied.

As is clear from the comparison between Comparative Example 6 and Invention Examples 53 to 56, a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure was added, and a treatment with a surface treating agent was carried out. In this case, the green compact density is improved, the ejection force is reduced, and the moldability is improved.

[0124]

[Table 13]

Example 12 A partially diffusion alloyed steel powder for powder metallurgy having an average particle size of about 80 μm and natural graphite having an average particle size of 23 μm or less are mixed, and 0.2% by weight of ethylene stearic acid monoamide and 0.2% by weight of ethylene stearic acid bisamide are mixed. %, Added and heated at 160 ° C. with mixing, then cooled to about 110 ° C.

To the obtained powder mixture, various kinds of organoalkoxysilane, organosilazane, titanate-based or fluorine-based coupling agent, silicone oil or alkylbenzene was further sprayed. The respective powder mixtures coated with the various surface treatment agents described above were mixed with a high-speed mixer for 1 minute under the condition of stirring blade rotation speed: 1000 rpm, and then cooled to 85 ° C or lower.

The above processing is referred to as preliminary processing C2. Table 12 shows the types and amounts of the surface treatment agents added in the pretreatment C2.
Shown in. The contents of the symbols described in the surface treatment agent column in Table 12 are as shown in Table 14. Next, to the obtained powder mixture, 0.1% by weight of lithium stearate and, in addition, a lubricant which is at least one of a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure is added in total. In an amount of 0.2% by weight, the mixture was uniformly stirred and mixed, and then discharged from the mixer (Invention Examples 57 to 59).

Table 12 shows the type and amount of the lubricant added.
Shown in. The contents of the symbols in the lubricant column in Table 12 are shown in the table.
As shown in 15. Then 100 g of the obtained powder mixture
After heating to a specified temperature of 20 to 140 ℃, the discharge hole diameter 5
The liquid was discharged from the orifice of mmΦ, the time until the discharge was completed was measured, and the fluidity was examined in the same manner as in Example 1.

Further, in parallel with the above liquidity survey,
The powder mixture discharged from the above mixer was molded into a tablet of 11 mmΦ with a molding pressure of 7 ton / cm ² while heating at 150 ° C., and the ejection force and the green compact density during molding were measured. The experimental results are shown in Table 12. Comparative Example 6 and invention example shown in Table 7 and Table 12
As is clear from the comparison of 57 to 59, when the treatment with the surface treatment agent is performed, the fluidity of the mixed powder at each temperature is significantly improved.

Further, as is clear from the comparison between Comparative Example 6 and Invention Examples 57 to 59, when the treatment with the surface treatment agent is carried out, the green compact density is improved and the ejection force is reduced, resulting in moldability. Has been improved.

[0131]

[Table 14]

Example 13 A partially diffusion alloyed steel powder for powder metallurgy having an average particle size of about 80 μm and natural graphite having an average particle size of 23 μm or less were mixed, and 0.2% by weight of ethylene stearic acid monoamide and 0.2% by weight of ethylene stearic acid bisamide were mixed. %, Added and heated at 160 ° C. with mixing, then cooled to about 110 ° C.

The powder mixture thus obtained was further sprayed with a suitable amount of various organoalkoxysilanes, organosilazanes, titanate or fluorine coupling agents, silicone oil or alkylbenzene . The respective powder mixtures coated with the various surface treatment agents described above were mixed with a high-speed mixer for 1 minute under the condition of stirring blade rotation speed: 1000 rpm, and then cooled to 85 ° C or lower.

The above processing is referred to as preliminary processing C2. Table 13 shows the type and amount of the surface treatment agent added in the pretreatment C2.
Shown in. The contents of the symbols described in the column of surface treatment agent in Table 13 are as shown in Table 14. Next, to the obtained powder mixture, 0.1% by weight of lithium stearate and, in addition, a lubricant which is at least one of a thermoplastic resin or a thermoplastic elastomer or a compound having a layered crystal structure is added in total. The amount was 0.2% by weight, and the mixture was stirred and mixed uniformly, and then discharged from the mixer (Invention Examples 60 to 63).

Table 13 shows the type and amount of the lubricant added.
Shown in. The contents of the symbols described in the lubricant column in Table 13 are shown in the table.
As shown in 15. Then 100 g of the obtained powder mixture
After heating to a specified temperature of 20 to 140 ℃, the discharge hole diameter 5
The liquid was discharged from the orifice of mmΦ, the time until the discharge was completed was measured, and the fluidity was examined in the same manner as in Example 1.

Further, in parallel with the above liquidity survey,
The powder mixture discharged from the above mixer was molded into a tablet of 11 mmΦ with a molding pressure of 7 ton / cm ² while heating at 150 ° C., and the ejection force and the green compact density during molding were measured. The experimental results are shown in Table 13. Comparative Example 6 and invention examples shown in Tables 7 and 13
As is clear from the comparison of 60 to 63, when the treatment with the surface treatment agent is performed, the fluidity of the mixed powder at each temperature is significantly improved.

Further, as is clear from the comparison between Comparative Example 6 and Invention Examples 60 to 63, even when only the treatment with the surface treatment agent is applied, the green compact density is improved and the ejection force is reduced. ,
Moldability is improved.

[0138]

[Table 15]

[0139]

[Table 16]

[0140]

[Table 17]

[0141]

According to the present invention, it has become possible to provide an iron-based powder mixture for powder metallurgy which can obtain excellent fluidity not only at room temperature but also at room temperature. Furthermore, according to the present invention, it is possible to provide an iron-based powder mixture for powder metallurgy, which has excellent fluidity, has reduced ejection force at the time of molding at room temperature and warm temperature, and has improved moldability. became.

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-148505 (JP, A) JP-A-5-117703 (JP, A) JP-A-3-162502 (JP, A) JP-A-6- 145701 (JP, A) JP-A-2-47201 (JP, A) JP-A-62-182418 (JP, A) JP-A-59-47301 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B22F 1/00-1/02

Claims (16)

(57) [Claims] 1. In an iron-based powder mixture containing an iron-based powder, a lubricant and an alloying powder, at least one selected from the iron-based powder, the lubricant and the alloying powder is an organoalkoxy.
Silane, organosilazane, silicone oil, titanium
-Based coupling agents, fluorine-based coupling agents and
An iron-based powder mixture for powder metallurgy having excellent fluidity and moldability, which is a powder coated with one or more surface-treating agents selected from alkylbenzenes . Wherein said organoalkoxysilane claim 1 for powder metallurgy iron-based powder mixture having excellent flowability and moldability according with substituted or unsubstituted organic group. 3. The powder having excellent fluidity and moldability according to claim 2, wherein the substituent of the organic group is at least one selected from organoalkoxysilanes which are an acrylic group, an epoxy group or an amino group. Iron-based powder mixture for metallurgy. Wherein said lubricant is a fatty acid amine Toori other fat
An acid amide and metal soap claims 1-3 for powder metallurgy iron-based powder mixture having excellent flowability and moldability of any one. Wherein said lubricant, in addition, inorganic compounds having a layered crystal structure, according to claim 4 comprising an organic compound having a layered crystal structure, at least one selected from thermoplastic resins and thermoplastic elastomers An iron-based powder mixture for powder metallurgy, which has excellent fluidity and moldability as described above. Wherein said fatty acid amide is a fatty acid monoamide and powder metallurgical iron-based powder mixture having excellent flowability and moldability of claim 4 or 5, wherein at least one selected from fatty acid bisamides. 7. The iron base for powder metallurgy having excellent fluidity and moldability according to claim 5, wherein the inorganic compound having a layered crystal structure is at least one selected from graphite, fluorocarbon and MoS _2. Powder mixture. 8. The melamine-cyanuric acid addition compound and / or N is an organic compound having a layered crystal structure.
An iron-based powder mixture for powder metallurgy having excellent fluidity and moldability according to claim 5, which is -alkyl aspartic acid-β-alkyl ester. 9. The powder having excellent fluidity and moldability according to claim 5, wherein the thermoplastic resin is at least one selected from powdery polystyrene, nylon, polyethylene and fluororesin having a particle size of 30 μm or less. Iron-based powder mixture for metallurgy. 10. The thermoplastic elastomer has a particle size of
An iron-based powder mixture for powder metallurgy having excellent fluidity and moldability according to claim 5, which is a powdered thermoplastic elastomer having a particle size of 30 µm or less. 11. The thermoplastic elastomer according to claim 5 or 10 , wherein the thermoplastic elastomer is at least one selected from a styrene thermoplastic elastomer, an olefin thermoplastic elastomer, an amide thermoplastic elastomer, and a silicone thermoplastic elastomer. An iron-based powder mixture for powder metallurgy, which has excellent fluidity and moldability as described above. 12. An iron-based powder mixture containing an iron-based powder, a lubricant and an alloying powder, wherein at least one selected from the iron-based powder, the lubricant and the alloying powder is an organoalkoxy compound.
Sisilane, organosilazane, silicone oil, titanium
Nate coupling agents, fluorine coupling agents and
And at least one surface treatment agent selected from alkylbenzene , the alloy powder contains at least graphite powder, the lubricant contains at least metal soap and fatty acid amide, and the graphite powder content is 0.05 to 1
An iron-based powder mixture for powder metallurgy excellent in fluidity and moldability, characterized in that the content of wt%, the content of fatty acid amide is 0.01 to 1.0% by weight, and the content of metal soap is 0.01 to 1.0% by weight. 13. At least one of them is an organoal.
Coxisilane, organosilazane, silicone oil,
Titanate coupling agent, Fluorine coupling agent
And an iron-based powder and an alloy powder coated with one or more surface-treating agents selected from alkylbenzene and fatty acid, fatty acid amide , thermoplastic resin, thermoplastic elastomer, and layered crystal structure. A step of adding one or more kinds selected from an inorganic compound and a lubricant which is an organic compound having a layered crystal structure or further adding a metal soap to carry out a primary mixing, and the mixture after the primary mixing among the above-mentioned lubricants A step of stirring while heating at least the melting point of at least one lubricant, melting the lubricant, cooling the mixture obtained after the melting step while mixing, and applying the lubricant to the surface of the iron-based powder by the lubricant. Fixing the alloy powder,
In the mixture containing the iron-based powder to which the alloying powder obtained in the step is fixed, metal soap, thermoplastic resin, fatty acid amide, thermoplastic elastomer, inorganic compound powder having a layered crystal structure and layered A method for producing an iron-based powder mixture for powder metallurgy having excellent fluidity and moldability, comprising the step of adding at least one selected from organic compound powders having a crystal structure and secondary mixing. 14. At least one of them is an organoal.
Coxisilane, organosilazane, silicone oil,
Titanate coupling agent, Fluorine coupling agent
And an iron-based powder and an alloy powder coated with one or more surface-treating agents selected from alkylbenzene ,
(1) Fatty acid amide and (2) Lubricants which are metal soaps, thermoplastic resins, thermoplastic elastomers, inorganic compounds having a layered crystal structure and organic compounds having a layered crystal structure, which have a higher melting point than the fatty acid amide. A step of adding one or more kinds selected from among the above to perform primary mixing, a step of stirring the mixture obtained in the primary mixing step while heating the mixture above the melting point of the fatty acid amide to melt the fatty acid amide, Cooling while mixing the mixture obtained after the melting step, the step of fixing the alloying powder to the surface of the iron-based powder by the lubricant, the iron-based powder to which the alloying powder obtained in the step is fixed In addition to the mixture containing, a metal soap, a thermoplastic resin, a fatty acid amide, a thermoplastic elastomer, an inorganic compound powder having a layered crystal structure and a layered crystal structure. Method for producing an organic compound at least one kind of added iron-based powder mixture for superior powder metallurgy flowability and moldability, characterized by comprising the step of mixing the secondary selected from among powders that. 15. Among iron-based powders and alloy powders, fatty acids, fatty acid amides , thermoplastic resins, thermoplastic elastomers, inorganic compounds having a layered crystal structure and lubricants which are organic compounds having a layered crystal structure A step of adding at least one metal soap selected from the following or further adding a metal soap and performing primary mixing, while heating the mixture obtained in the primary mixing step to the melting point of at least one of the above-mentioned lubricants Stirring and melting the lubricant; cooling the mixture obtained in the melting step while mixing;
In the temperature range of 0 to 140 ℃, organoalkoxysilane,
Luganosilazane, silicone oil, titanate cup
Pulling agents, fluorine coupling agents and alkyl
A step of adding and mixing one or more surface-treating agents selected from the group consisting of a metal soap, a thermoplastic resin, a fatty acid amide, a thermoplastic elastomer, and a layered layer. A powder excellent in fluidity and moldability, which comprises a step of adding at least one selected from an inorganic compound powder having a crystal structure and an organic compound powder having a layered crystal structure, and performing secondary mixing. A method for producing an iron-based powder mixture for metallurgy. 16. An iron-based powder and a powder for alloys are added to (1) a fatty acid amide and (2) a metal soap, a thermoplastic resin, a thermoplastic elastomer having a melting point higher than that of the fatty acid amide,
1 selected from an inorganic compound having a layered crystal structure and a lubricant that is an organic compound having a layered crystal structure
A step of adding at least one species and performing primary mixing; a step of stirring the mixture obtained in the primary mixing step at a temperature equal to or higher than the melting point of the fatty acid amide to melt the fatty acid amide; Organo in the temperature range of 100 to 140 ° C
Alkoxysilane, organosilazane, silicone oil
, Titanate coupling agent, fluorine coupling
At least one selected from the group
That mixing added surface treatment agent, to the mixture surface treatment agent obtained was added in about該工, further inorganic compounds having metallic soap, thermoplastic resin, fatty acid amides, thermoplastic elastomers, a layered crystal structure A powder and an iron-based powder mixture for powder metallurgy excellent in fluidity and moldability, which comprises a step of adding at least one selected from powders and organic compound powders having a layered crystal structure and secondary mixing Manufacturing method.