JP2011140535A - Method for producing organic binder and organic binder - Google Patents

Abstract

An organic binder capable of preventing the generation of bubbles and cracks in a sintered product and a method for producing the same are provided.
A component a which is a water-soluble polymer having a Vicat softening point of less than 80 ° C, a component b which is a water-insoluble thermoplastic polymer having a Vicat softening point of 90 ° C or more, and a melt viscosity at 150 ° C of 200 mPa · s or less. Component c which is a water-insoluble organic compound and component d which is a water-insoluble thermoplastic polymer having a Vicat softening point of less than 100 ° C. are 50 to 80 vol%, 5 to 35 vol%, 10 to 40 vol%, respectively, in the order of description, And the mixture contained in the ratio of 5-20 vol% is heated and melted to a temperature at which all of the components a to d are melted. Next, the molten mixture is charged into water that has been adjusted to a temperature below the melting point of component c and stirred to produce a granular intermediate. Finally, the granular intermediate produced is dried and pulverized to obtain an organic binder used in the powder injection molding method.
[Selection] Figure 1

Description

  The present invention relates to an organic binder used for powder injection molding (MIM) and a method for producing the same.

In recent years, a powder injection molding method has been used to mold ceramics and metal products having complicated shapes. This powder injection molding method was obtained by adding various organic compounds and a thermoplastic resin to give a sinterable powder fluidity, followed by heating and kneading and then injection molding as a raw material for molding. A sintered product is manufactured by degreasing and sintering the compact.
A conventionally used molding raw material having fluidity is, for example, a metal powder to which an organic binder such as a thermoplastic resin having a relatively high melting point and a wax having a lower melting point is added. The forming raw material is obtained by uniformly kneading the sintering powder and the organic binder with a kneader while heating the organic binder to the melting point of the organic binder or higher.

  However, since the thermoplastic resin used as the organic binder is generally supplied as a cylindrical pellet of about 5 mm, the size is extremely different from a metal powder having an average particle size of 10 μm or less. Further, the thermoplastic resin has a higher viscosity at the time of kneading than the wax or the like used at the same time. For these reasons, there has been a problem that it is not easy to uniformly disperse the metal powder or the like in the thermoplastic resin and wax using a kneader, and the kneading operation takes a long time.

In order to solve the problem, Patent Document 1 proposes a technique in which a thermoplastic resin obtained in pellets is pulverized in advance and then kneaded with a metal powder.
However, in the method in which the thermoplastic resin proposed in Patent Document 1 is pulverized in advance, the dispersion after kneading is agglomerated, and it is necessary that a pulverization process is required for the convenience of the subsequent process. (Patent Document 2). Patent Document 2 uses, as an organic binder, a mixture of an organic compound powder such as a thermoplastic resin and a liquid organic compound such as a phthalic acid plasticizer, together with a powder that can be sintered. Techniques for heating and mixing are disclosed.

JP 11-269504 A JP 2001-303103 A

  In the technique disclosed in Patent Document 2 in which an organic compound powder and a liquid organic compound are used as an organic binder, an unmelted powder organic compound is easily blocked when heated and mixed with a metal powder or the like and a mixed organic binder. The metal powder or the like surrounds the blocked powdered organic compound, so that there is a possibility that tens of microns of bubbles and cracks due to the bubbles are included in the molded body after degreasing.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an organic binder capable of preventing the generation of bubbles and cracks in a sintered product, and a method for manufacturing the same.

  The production method according to the present invention is a method for producing an organic binder used in a powder injection molding method, which is a component a which is a water-soluble polymer having a Vicat softening point of less than 80 ° C., and a non-cutting Vicat softening point of 90 ° C. or more. Component b which is a water-soluble thermoplastic polymer, component c which is a water-insoluble organic compound having a melt viscosity at 150 ° C. of 200 mPa · s or less, and a water-insoluble thermoplastic polymer having a Vicat softening point of less than 100 ° C. All components a to d are melted in a mixture containing component d in the order of 50 vol% or more and 80 vol% or less, 5 vol% or more and 35 vol% or less, 10 vol% or more and 40 vol% or less, and 5 vol% or more and 20 vol% or less. The molten mixture is heated to a melting temperature, and the melted mixture is poured into stirred water adjusted to a temperature below the melting point of the component c. The intermediate is produced, it is an powder by drying the particulate intermediate.

In the said manufacturing method, the average particle diameter of the said granular intermediate body produced | generated by making the stirring conditions of the water which throws in the said molten mixture into a turbulent flow shall be 100 micrometers or less.
The component b is composed of one or more selected from polyacetal, high density polyethylene, polypropylene, polystyrene, polybutene 1, cycloolefin copolymer, and styrene-methacrylate copolymer.

The component c is at least one selected from fatty acid esters, fatty acid amides, phthalic acid esters, microcrystalline wax, paraffin wax, polyethylene wax, polypropylene wax, carnauba wax, montan wax, urethanized wax, and maleic anhydride modified wax. Become.
Component d is amorphous polyolefin, ethylene vinyl acetate copolymer, polyvinyl butyral resin, glycidyl methacrylate resin, methyl methacrylate resin, ethyl methacrylate resin, butyl methacrylate resin, ethylene glycidyl methacrylate copolymer, ethylene / acrylic acid / maleic anhydride. It comprises at least one selected from a copolymer, a maleic anhydride grafted polyolefin resin, an ethylene / vinyl acetate / maleic anhydride copolymer and an ethylene / ethyl acrylate copolymer.

  The organic binder according to the present invention is an organic binder used in a powder injection molding method, which is a water-soluble polymer component a having a Vicat softening point of less than 80 ° C, and a water-insoluble heat having a Vicat softening point of 90 ° C or more. A component b which is a plastic polymer, a component c which is a water-insoluble organic compound having a melt viscosity at 150 ° C. of 200 mPa · s or less, and a component d which is a water-insoluble thermoplastic polymer having a Vicat softening point of less than 100 ° C. Up to a temperature at which a mixture containing 50 vol% or more and 80 vol% or less, 5 vol% or more and 35 vol% or less, 10 vol% or more and 40 vol% or less, and 5 vol% or more and 20 vol% or less is melted. The mixture heated and melted in water that has been heated and melted, adjusted to a temperature lower than the melting point of the component c, and stirred is put into a raw material. The average particle size granular intermediate was formed by drying is is less powder 100 [mu] m.

The water in the “stirred water” includes water containing a water-soluble component other than ultrapure water, distilled water and the like.
The “turbulent flow” refers to a case where the stirring Reynolds number is 4000 or more.
The “average particle diameter” is an average length diameter measured by a particle size distribution measuring apparatus using a laser diffraction / scattering method.

  ADVANTAGE OF THE INVENTION According to this invention, the organic binder which can prevent generation | occurrence | production of the bubble and a crack in a sintered compact product, and its manufacturing method can be provided.

FIG. 1 is a schematic view of an organic binder manufacturing process. FIG. 2 is a flowchart of the manufacturing process of the sintered body product. FIG. 3 is an enlarged image of the organic binder adjusted according to the first embodiment. FIG. 4 is an enlarged image of the organic binder adjusted according to the second embodiment.

FIG. 1 is a schematic view of an organic binder manufacturing process.
The “organic binder” according to the present invention is mixed with metal, ceramic or cermet powder in a powder injection molding method (MIM) to enable injection molding of these powders.
The organic binder is obtained using component a, component b, component c and component d as raw materials.

Hereinafter, component a, component b, component c, and component d will be described.
As the component a, a thermoplastic water-soluble polymer having a Vicat softening point of less than 80 ° C. is used.
As the component a, specifically, one or more of polyhydric alcohols such as polyethylene glycol and polypropylene glycol and polyethers such as polyethylene oxide and polypropylene oxide are used, and polyethylene glycol and polyethylene oxide are preferable.

  As the component b, a water-insoluble thermoplastic polymer having a Vicat softening point of 90 ° C. or higher is used. The component b is specifically selected from polyacetal, high-density polyethylene, polypropylene, polystyrene, polyoxymethylene, polybutene 1 (1-butene polymer), polystyrene, styrene-methacrylate copolymer, and cycloolefin copolymer. One or more types can be used. In consideration of the flowability and rigidity at the time of injection molding of the raw material for molding mixed with metal powder, etc., at least one resin selected from polypropylene polyoxymethylene, styrene-methacrylate, and polystyrene is obtained. Is preferred.

  As the component c, a water-insoluble organic compound having a melt viscosity at 150 ° C. of 200 mPa · s or less is used. Specifically, fatty acid ester, fatty acid amide, higher fatty acid, phthalic acid ester, adipic acid ester, paraffin wax, microcrystalline wax, polyethylene wax, polypropylene wax, carnauba wax, montan wax, urethanized wax, maleic anhydride modified wax 1 or more types selected from can be used.

  As the component d, a water-insoluble polymer having a Vicat softening point of less than 100 ° C. is used. Specifically, low density polyethylene, amorphous polyolefin, ethylene vinyl acetate copolymer, polyvinyl butyral resin, glycidyl methacrylate resin, methyl methacrylate resin, ethyl methacrylate resin, butyl methacrylate resin, ethylene glycidyl methacrylate copolymer, ethylene / acrylic acid / A resin comprising at least one selected from a maleic anhydride copolymer, a maleic anhydride grafted polyolefin resin, an ethylene / vinyl acetate / maleic anhydride copolymer, and an ethylene / ethyl acrylate copolymer can be used.

The organic binder is manufactured as follows.
Referring to FIG. 1, first, predetermined amounts of component a, component b, component c, and component d are charged into mixer 1. The predetermined amount means that component a is in the range of 50 to 80 vol%, component b is 5 to 35 vol%, component c is 10 to 40 vol%, and component d is 5 to 20 vol%.

For the mixer 1, for example, an apparatus for powder mixing such as a V-type mixer is used. The mixing operation by the mixer 1 is performed until any one of the components a to d becomes substantially uniform in the plug body without being unevenly distributed (FIG. 1A, mixing step).
A mixture of components a to d mixed by the mixer 1 (hereinafter referred to as “mixed intermediate”) is supplied to a twin-screw extruder 2 controlled at a temperature of 100 ° C. or higher and melted by the twin-screw extruder 2. The mixed intermediate is extruded in a string form from a strand die (nozzle head) 11 (FIG. 1B, melting step).

  The mixed intermediate extruded in a string shape is charged into water (warm water) in the stirring tank 3 which is controlled to a predetermined temperature and stirred by the stirring blade 12. In the stirring tank 3, the water-soluble component a elutes in water from the added mixing intermediate. Since the components a to d are uniformly melted (dispersed), the mixture of the components b to c which are insoluble in water with the elution of the component a into water is composed of fine particles (hereinafter referred to as “granular intermediate”). And dispersed in warm water (FIG. 1 (c), granulating step).

The “predetermined temperature” that is the control temperature is a temperature lower than the melting point of the component c.
The amount of water in the agitation tank 3 is, for example, 200 L with respect to 50 kg of the mixed intermediate extruded by the twin-screw extruder 2.
Even after the entire amount of the mixed intermediate is put into the stirring tank 3, stirring by the stirring blade 12 is continued, and the granular intermediate is supplied to the pressure filtration device (filter press) 4 in a state of being dispersed in water for dehydration. (FIG. 1 (d), dehydration step).

The dehydrated granular intermediate is transferred to the tray 13 and then placed in the vacuum dryer 5 and dried to become an organic binder of fine particles (FIG. 1 (e), drying step).
Next, the manufacturing process of the sintered compact product using the organic binder obtained as mentioned above is demonstrated.
FIG. 2 is a flowchart of the manufacturing process of the sintered body product.

  First, an organic binder and a powder sintered material (hereinafter referred to as “sintering powder”) are charged into a mixer and mixed uniformly (# 1). For the mixer, an apparatus for powder mixing such as a V-type mixer is used. The time required to uniformly mix the organic binder and the sintered material varies depending on the size of the mixer, the amount of the organic binder and the sintered material, etc., so obtain the relationship between the mixing time and the degree of mixing in advance. Mixing time is determined.

  The mixture of uniformly mixed organic binder and sintering powder is convenient for injection molding by a continuous kneader such as a batch kneader or an extruder controlled at a constant temperature of 100 ° C. or higher, for example. (# 2). A mixture of the granulated organic binder and the sintered material is referred to as “forming raw material (or feedstock)”. When an extruder that performs kneading and granulation in series is not used, the mixture of the organic binder and the sintering powder uniformly kneaded with a batch kneader is granulated with a granulating machine.

Granular (pellet-shaped) molding raw materials having a uniform size by granulation are molded into a molded body by an injection molding machine (# 3).
The formed body is housed in a sealed degreasing furnace and degreased by gradually raising the temperature from room temperature in a nitrogen atmosphere (# 4). The processing temperature for degreasing is, for example, 50 to 600 ° C. Prior to degreasing by raising the temperature, component c may be extracted and removed with a solvent.

The degreased shaped body is naturally cooled or forcedly cooled and transferred to a sintering furnace. The molded body is sintered in a sintering furnace heated from room temperature to 1000 ° C. or higher in an argon atmosphere (# 5), and is naturally or forcedly cooled and then taken out from the sintering furnace as a sintered body product. It is.
The sintering process is performed at a temperature of 800 to 1500 ° C. or higher according to the sintering characteristics of the powder.

In addition, the degreasing treatment and the sintering treatment can be performed in one heating furnace, and by using a degreasing furnace and a sintering furnace equipped with a pusher type, walking beam type conveying machine capable of automatically conveying a molded body, The molded product can be degreased and fired.
Next, the influence of the components a to d at the time of adjusting the organic binder to the sintered body product will be described. Table 1 shows the usage ratios of various components a to d during the production of the organic binder, and Table 2 shows the shape of the organic binder manufactured with the usage ratios of the various components a to d and the manufacturing process of the sintered product using the same. Etc. are shown.

Manufacture of the organic binder by the combination of component ad shown in Table 1 was performed as follows.
The individual raw materials belonging to any of the components a to d are introduced into a V-type mixer so that the total weight is 50 kg and mixed substantially uniformly.
Here, the Vicat softening point of polyoxymethylene (Polyplastics Corporation, Duracon (registered trademark)) in component b of Table 1 is 155 ° C., polystyrene (DIC Corporation, Dick Styrene (registered trademark), CR-3500) The Vicat softening point is 92 ° C., and the Vicat softening point of polypropylene (Sumitomo Chemical Co., Ltd., Sumitomo Noblen (registered trademark), Z144) is 125 ° C.

  Paraffin wax in Component c (Nippon Steel Co., Ltd., F140 has a viscosity of 100 mPa · s or less at 150 ° C., and polypropylene wax (Sanyo Chemical Industries, Ltd., Viscol (registered trademark), 660-P) has a viscosity of 150 ° C. The viscosity of phthalic acid ester (reagent, dibutyl phthalate) is 100 mPa · s or less at 150 ° C., the viscosity of stearic acid (reagent) is 100 mPa · s or less at 150 ° C., and carnauba wax (Toagosei Co., Ltd.). , Purified carnauba wax) has a viscosity of 100 mPa · s or less at 150 ° C.

  The Vicat softening point of the ethylene glycidyl methacrylate copolymer (Sumitomo Chemical Co., Ltd., Bond First (registered trademark)) in component d is less than 90 ° C, the Vicat softening point of polyvinyl butyral (reagent) is less than 100 ° C, amorphous polyolefin (trade name) APAO Rextac) has a Vicat softening point of less than 80 ° C., Polybutylmethacrylate (Kyoeisha Chemical Co., Ltd., 1700) has a Vicat softening point of less than 90 ° C., low density polyethylene (Sumitomo Chemical Co., Sumikasen (registered trademark), G806) The Vicat softening point is less than 100 ° C, and the Vicat softening point of ethylene vinyl acetate (Tosoh Corporation, Ultrasen (registered trademark), 633) is less than 70 ° C.

  Subsequently, the mixed intermediate mixture is melted by a twin screw extruder controlled at 140 ° C., and the mixed intermediate extruded from the strand die is stirred at a temperature adjusted to 40 ° C. and containing 200 L of hot water to be stirred. Put directly into the tank. The stirring blade and the number of rotations in the stirring tank are preferably such that the flow of the dispersion is equal to or higher than the transition region between laminar flow and turbulent flow even when the total amount (40 kg) of the mixed intermediate is charged and dispersed in warm water. More preferably, it is a turbulent flow. The laminar flow and the turbulent flow are determined by the stirring Reynolds number calculated from the shape of the stirring blade, the number of rotations, and the density and viscosity of the fluid. Here, the turbulent flow is defined as a case where the stirring Reynolds number is 4000 or more.

The granular intermediate dispersed in warm water (water) was dehydrated with a filter press and dried with a vacuum dryer to obtain an organic binder.
The shape of the organic binder shown in Table 2 is obtained by observing an image displayed on a display after being enlarged with a microscope and detected by an image sensor (CCD) in a state dispersed in water before dehydration by a filter press. (See FIGS. 3 and 4).

The average particle diameter of the organic binder shown in Table 2 is the length average diameter measured by a particle size distribution measuring apparatus using a laser diffraction / scattering method. Hereinafter, the “average particle diameter” for the organic binder refers to an average length diameter measured by a particle size distribution measuring apparatus using a laser diffraction / scattering method.
Moreover, the process until obtaining the sintered compact product shown in Table 2 was performed as follows.

A SUS316L powder having an average particle diameter of 10 μm or a zirconia powder having a specific surface area of 11.2 m 2 / g was used as a powder for sintering and mixed with the organic binder shown in Table 1 by a V-type mixer.
A mixture of such a powder for sintering and an organic binder is kneaded in a batch system controlled at a constant temperature (for example, 170 ° C. in Example 1 and 150 ° C. in Example 2) according to the Vicat softening point of component b. The mixture was kneaded by a machine, and a pelletized molding material having a diameter of about 3 mm and a length of about 3 mm was obtained using a granulator.

The obtained molding raw material was injection-molded using a rectangular shaped mold having a thickness of 5 mm, a length of 50 mm and a width of 10 mm, and the molded body was elevated from room temperature to 500 ° C. over 12 hours in a nitrogen atmosphere. The sample was heated, held at 500 ° C. for 2 hours, and then cooled to room temperature for degreasing.
When SUS316L powder is used for sintering, the degreased compact is heated in a sintering furnace from room temperature to 1350 ° C. in an argon atmosphere for 8 hours, held for 2 hours, and then cooled to room temperature. It was. When zirconia powder is used, sintering is performed by heating the degreased molded body from room temperature to 1600 ° C. in an air atmosphere in a sintering furnace in 12 hours, holding for 2 hours, and then cooling to room temperature. I went.

The internal defect of the molded body, the internal defect of the degreased product, and the internal defect of the sintered body product in Table 2 were determined visually by dividing the molded body into two parts. The density of the sintered product was measured by helium gas replacement using a dry automatic densimeter (Acupick, manufactured by Shimadzu Corporation). The density of the sintered product was judged to be appropriate when the density was 94% or more.
From Table 1 and Table 2, component a was produced at 55 vol% or more and 75 vol% or less, component b was produced at 6 vol% or more and 13 vol% or less, component c was produced at 13 vol% or more and 23 vol% or less, and component d was produced at 6 vol% or more and 13 vol% or less. It can be seen that the sintered body product sintered using the organic binder does not have internal defects such as bubbles and cracks.

  Until now, powder injection molding methods have had problems such as blisters and micropores (bubbles) generated by aggregation of organic binders. However, the organic binder prepared by mixing the components a to d at the above ratio has a particle size of 100 μm or less (see Table 2), and thus does not cause defects in the degreasing process and the sintering process, and is healthy. Sinter products can be manufactured.

3 is an enlarged image of the organic binder adjusted according to the first embodiment, and FIG. 4 is an enlarged image of the organic binder adjusted according to the second embodiment. From FIG. 3 and FIG. 4, it is observed that the resulting organic binder is spherical.
The amount of polyethylene glycol remaining in the organic binder of Example 1 was 0.7% by weight, and the amount of polyethylene glycol remaining in the organic binder of Example 2 was 0.8% by weight. The amount of polyethylene glycol remaining in the organic binder was measured using a TG-DTA (manufactured by Shimadzu Corporation) and a dry automatic densimeter (manufactured by Shimadzu Corporation, Accupic).

In the organic binder, component a is mixed at a ratio of 50 vol% to 80 vol%, component b is mixed at 5 vol% to 35 vol%, component c is mixed at 10 vol% to 40 vol%, and component d is mixed at a ratio of 5 vol% to 20 vol%. Preferably it is manufactured.
When the component a is used in an amount of more than 80 vol%, the dehydration becomes incomplete and the drying time becomes long. The use of component a exceeding 80 vol% is caused by the re-aggregation of dispersed particles composed of component b, component c, and component d, resulting in many particles having a particle size exceeding 100 μm, and a desired organic binder having an average particle size of 100 μm or less. It becomes difficult to obtain stably.

In addition, when the component a is less than 50 vol%, the mixture of the components b to d produced by the elution of the component a into warm water in the granulation step is not smoothly dispersed, and fine particles (granular intermediate) are obtained. I can't.
As described above, the amount of component a used is preferably 55 vol% or more and 75 vol% or less, and an organic binder having a particle size of 100 μm or less is obtained under the condition where the amount of component a used is 60 vol% or more and 70 vol% or less. Ideal for.

An organic binder produced using less than 5 vol% of component b has a low strength of an injection molded product (molded product) obtained by using this. When the component b is used in an amount of more than 35 vol%, the demolding of the injection molded body (molded body) is not performed smoothly, and cracks and swelling due to incomplete degreasing tend to occur inside the molded body.
When the component c used in the mixing step is less than 10 vol%, the fluidity at the time of injection molding of the molding raw material mixed with the obtained organic binder is deteriorated, and cracks and cracks are likely to occur in the molded body. . When the amount of component c used is more than 40 vol%, burrs are likely to occur in the molded body during injection molding, and the strength of the molded body may be reduced. Also, deformation is likely to occur during the degreasing process.

  When the component d used is less than 5 vol%, the fluidity at the time of injection molding of the molding raw material mixed with the obtained organic binder is deteriorated, the flexibility of the molded body is impaired, and the molded body is cracked. And cracks are likely to occur. If the amount of component d used is more than 20 vol%, burrs are likely to occur in the molded body during injection molding, and the strength of the molded body may be reduced. Also, deformation is likely to occur during the degreasing process.

  The organic binder in Examples 1-8 whose average particle diameter is 100 micrometers or less also has the following effects. For example, in a conventional organic binder, a kneading time of about 2 hours is required to obtain a kneaded product with about 10 kg of a sintering powder with a batch kneader. On the other hand, when an organic binder having an average particle size of 100 μm or less is used, the kneading time can be shortened to 30 minutes or less.

Materials for the powder for sintering mixed with the organic binder are metals, ceramics, and cermets.
As the metal, stainless steel, iron-based material, titanium, copper, nickel alloy, chromium alloy, tungsten alloy, or the like is used. The average particle size of the metal powder is preferably 1 to 30 μm. When the average particle size of the metal powder is 1 μm or less, the amount of the organic binder necessary for molding increases, so that defects such as deformation, cracking, and swelling are likely to occur during degreasing. When the average particle size of the metal powder is 30 μm or more, the powder and the organic binder are easily separated at the time of molding, the density after sintering is lowered, and the strength of the obtained sintered product is also lowered. The average particle diameter of the sintering powder is an average diameter of 50% cumulative weight measured using a particle size distribution measuring apparatus using a laser diffraction / scattering method.

Examples of the sinterable ceramic powder include oxide ceramics, nitride ceramics, and carbide ceramics.
Examples of the oxide ceramic include alumina powder and zirconia powder, and examples of the nitride ceramic include silicon nitride and aluminum nitride.
An example of the carbide ceramic is silicon carbide.

In addition to the ceramics described above, sialon or one or more composite materials of the ceramics can be used. In addition, for the purpose of improving the sintering density, the strength after sintering, and the like when using these powders, powders such as yttrium oxide, magnesium oxide, calcium oxide, cerium oxide may be added as appropriate.
The average particle size of the ceramic powder used for the production of the sintered product is optimally 1 μm or less in order to improve the sintered density.

  As the sinterable cermet powder, a material obtained by adding cobalt, nickel or the like to tungsten carbide powder, or a material obtained by adding cobalt, nickel or the like to titanium nitride or titanium carbide powder is used. The amount of cobalt, nickel, and the like used can be appropriately adjusted depending on the strength and sintered density of the objective sintered product. The average particle size of tungsten carbide, titanium nitride, and titanium carbide powder is optimally 5 μm or less in order to improve the strength and sintered density of the sintered product. The average particle diameter of the added material such as cobalt or nickel is optimally 10 μm or less in order to improve the sintered density of the sintered product.

In the above-described embodiment, the apparatus used for the mixing step 1, the melting step, the granulating step, the dehydrating step, and the drying step may be based on another method having the same function.
In addition, the raw materials used as the components a to d can be appropriately changed in accordance with the spirit of the present invention.

  The present invention can be used for an organic binder used in a powder injection molding method (MIM) and a manufacturing method thereof.

Claims (6)

A method for producing an organic binder used in a powder injection molding method,
Component a which is a water-soluble polymer having a Vicat softening point of less than 80 ° C., component b which is a water-insoluble thermoplastic polymer having a Vicat softening point of 90 ° C. or more, and a water-insoluble solution having a melt viscosity at 150 ° C. of 200 mPa · s or less Component c, which is a water-soluble organic compound, and component d, which is a water-insoluble thermoplastic polymer having a Vicat softening point of less than 100 ° C., are 50 vol% or more and 80 vol% or less, 5 vol% or more and 35 vol% or less, 10 vol% or more and 40 vol, respectively. %, And a mixture contained in a ratio of 5 vol% or more and 20 vol% or less is heated to a temperature at which all of the components a to d are melted,
The molten mixture is poured into water that has been adjusted to a temperature below the melting point of component c and stirred to produce a granular intermediate;
A method for producing an organic binder, wherein the granular intermediate is dried to form a powder. The method for producing an organic binder according to claim 1, wherein an average particle diameter of the granular intermediate formed by making the stirring condition of water into which the molten mixture is charged is turbulent is 100 µm or less. The component b is
The method for producing an organic binder according to claim 1 or 2, comprising at least one selected from polyacetal, high density polyethylene, polypropylene, polystyrene, polybutene 1, cycloolefin copolymer, and styrene-methacrylate copolymer. The component c is
The fatty acid ester, fatty acid amide, phthalic acid ester, microcrystalline wax, paraffin wax, polyethylene wax, polypropylene wax, carnauba wax, montan wax, urethanized wax, and maleic anhydride modified wax. The manufacturing method of the organic binder of any one of Claim 3. The component d is
Amorphous polyolefin, ethylene vinyl acetate copolymer, polyvinyl butyral resin, glycidyl methacrylate resin, methyl methacrylate resin, ethyl methacrylate resin, butyl methacrylate resin, ethylene glycidyl methacrylate copolymer, ethylene / acrylic acid / maleic anhydride copolymer, anhydrous The organic binder according to any one of claims 1 to 4, comprising at least one selected from a maleic acid grafted polyolefin resin, an ethylene / vinyl acetate / maleic anhydride copolymer and an ethylene / ethyl acrylate copolymer. Production method. An organic binder used in powder injection molding,
Component a which is a water-soluble polymer having a Vicat softening point of less than 80 ° C., component b which is a water-insoluble thermoplastic polymer having a Vicat softening point of 90 ° C. or more, and a water-insoluble solution having a melt viscosity at 150 ° C. of 200 mPa · s or less Component c, which is a water-soluble organic compound, and component d, which is a water-insoluble thermoplastic polymer having a Vicat softening point of less than 100 ° C., are 50 vol% or more and 80 vol% or less, 5 vol% or more and 35 vol% or less, 10 vol% or more and 40 vol, respectively. %, And a mixture contained in a proportion of 5 vol% or more and 20 vol% or less is heated and melted to a temperature at which all of the components a to d are melted,
Powder having an average particle size of 100 μm or less formed by drying a granular intermediate produced by charging the mixture heated and melted in water that has been adjusted to a temperature lower than the melting point of component c and stirred. An organic binder characterized by