JP2011189631A - Insert molding, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a junction strength to a resin material by only formation treatment of a coating film layer of triazine dithiol derivative, irrespective of a kind of a metal material, and to enhance a manufacturing efficiency. <P>SOLUTION: This insert molding S is joined by insert-molding the resin material R, to the metal material M formed with the coating film layer F of triazine dithiol derivative on a surface, and the metal material M is constituted of a sintered body manufactured by a metal injection molding method. The metal injection molding method is called as a so-called MIM (metal injection molding) method, and is a method of adding a binding material of imparting flowability such as a resin and wax to metal powder, of imparting plasticity by heating/kneading, to be injection-molded as same as a plastic, and of obtaining the desired sintered body thereafter by defatting and sintering. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an insert molded product in which a metal material and a resin material are integrated by insert molding, and a method for manufacturing the insert molded product. In particular, the resin material is bonded to a metal material having a coating layer of a triazine dithiol derivative formed on the surface. The present invention relates to an insert molded product and a method for producing the insert molded product.

Conventionally, as this type of insert-molded product, for example, a technique disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2006-305838) is known.
In this method, a mixed layer of this metal material and aluminum is formed on the surface of the metal material, and a coating layer of a triazine dithiol derivative is formed, and a resin material is joined to the coating layer of this metal material by insert molding. is there. As a result, the bonding strength between the metal material and the resin material is increased, and in particular, since aluminum has a high reactivity with the triazine dithiol derivative, by forming a mixed layer of the metal material and aluminum on the surface, relatively In the ferrous metal having inferior bonding interface strength, the bonding strength can be increased.

JP 2006-305838 A

By the way, in the above-mentioned conventional insert-molded product, a mixed layer of a metal material and aluminum is formed on the surface of the metal material, so it is excellent for joining ferrous metals, but the surface treatment of the metal material is complicated accordingly. There was a problem that efficiency was bad. In particular, in the case of precision parts, the thickness of the mixed layer with aluminum must be taken into consideration, so that the degree of freedom in design is limited.
The present invention has been made in view of the above problems, and it is possible to improve the bonding strength with a resin material only by forming a film layer of a triazine dithiol derivative regardless of the type of metal material. It is an object of the present invention to provide an insert molded product and an insert molded product manufacturing method with improved efficiency.

  In order to achieve such an object, the insert molded product of the present invention is an insert molded product in which a resin material is joined by insert molding to a metal material having a coating layer of a triazine dithiol derivative formed on the surface. The structure is a sintered body manufactured by a metal injection molding method.

  The metal injection molding method is referred to as a so-called “MIM (Metal Injection Molding)” method, and since metal parts having complicated shapes can be mass-produced by a process similar to that of plastics, it has recently attracted attention as a metal processing method. In the MIM method, a binder (binder) that imparts fluidity such as resin or wax is added to metal powder, heated and kneaded to impart plasticity, injection-molded in the same way as plastic, and then the binder is removed ( Degreasing) and sintering to obtain a desired metal part. Since the MIM method is particularly excellent for mass production of precision parts using special materials, it is used as a processing method for many parts such as medical equipment parts, automobile parts, and OA equipment parts.

Moreover, the film layer formation of a triazine dithiol derivative is performed by well-known methods, such as an electric field polymerization process method and an immersion process method, for example.
In the electropolymerization method, an electrolytic solution is prepared by dissolving a triazine dithiol derivative together with an electrolyte substance in water or an organic solution. In an electrolytic cell in which the electrolytic solution is placed, a metal material is used as an anode, a cyclic method, a constant current method, A film of the triazine dithiol derivative is formed on the surface of the metal material while polymerizing the triazine dithiol derivative by an electrolysis method such as a constant potential method, a pulse constant potential method, and a pulse constant current method.
In the immersion treatment method, a triazine dithiol derivative is dissolved in water or an organic solvent to prepare an immersion liquid, and an object is immersed in the immersion liquid to form a film of the triazine dithiol derivative on the surface of the metal material.

  Thereby, since the metal material is a sintered body manufactured by the MIM method, it is porous. When a coating layer of the triazine dithiol derivative is formed on the surface of the sintered body, the surface of the sintered body is Triazine dithiol derivative enters the pores. Therefore, when injection molding is performed in the injection molding apparatus, when the molten resin material is injected into the mold cavity loaded with the metal material, the resin material is bonded to the metal material via the triazine dithiol derivative. In this case, since the resin material enters the pores on the surface of the sintered body and is joined to the metal material via the triazine dithiol derivative, the joining is further strengthened. Therefore, the bonding strength with the resin material can be improved only by forming the coating layer of the triazine dithiol derivative regardless of the type of the metal material, and the production efficiency can be improved. In addition, since the metal material and the resin material are joined directly rather than through the aluminum mixed layer as in the past, the accuracy can be improved, and it can contribute to the manufacture of precision parts. become. In particular, it is effective for ferrous metals.

  And, if necessary, the metal material is at least one of iron, copper, aluminum, nickel, gold, silver, platinum, palladium, cobalt, zinc, lead, tin, titanium, chromium, magnesium, manganese and alloys thereof The structure is selected from one type. As described above, the type of metal material is not limited, but it is particularly effective for this type of metal used for precision parts.

  In this case, the metal material is a ferrous metal as necessary. Examples of ferrous metals include pure iron, ordinary steel, and special steel. Examples of the normal steel include SS, SC, SPC, SPCC, and the like when represented by JIS display. Examples of the special steel include SUS, SMn, SCr, SCM, SNCM, SWRH, SUH, SK, SKH, SKS, SKD, SKC, SUP, SWRS, SUJ, and the like. Since ferrous metals are versatile materials with excellent mechanical strength and the like, it is significant that an insert-molded product having practical joint interface strength can be obtained using ferrous metals.

  If necessary, the resin material may be polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyvinyl acetate, ABS resin, polyisobutylene, ethylene propylene polymer, polyacrylic ester, polymethacrylic ester, polyacrylonitrile, poly Cyanoacrylate, polyvinyl ether, polyvinylidene chloride, polyvinyl carbazole, polyvinyl pyrrolidone, polyvinyl imidazole, polyisoprene, polybutadiene, butadiene-styrene rubber, butadiene-acrylonitrile rubber, polychloroprene, polyacetal, ethylene propylene diene rubber, polyamide (nylon 6, nylon 66, nylon 11), polyimide, polyetherimide, silicone resin, silicone rubber, polyurethane, epoxy resin , Polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, polysulfone, polycarbonate, polyetherimide, polyethersulfone, has a configuration selected from at least any one of a poly ethylidenenorbornene.

In addition, the manufacturing method of the insert molded product of the present invention for achieving the above object is an insert molded product in which a resin material is joined by insert molding to a metal material having a coating layer of a triazine dithiol derivative formed on the surface thereof. In the manufacturing method,
A mixing step of mixing a metal powder and a binder to obtain a mixture;
An injection molding step of molding the mixture obtained in the mixing step into a molded body of a required shape in a metal injection molding machine;
A degreasing step for degreasing the molded body obtained in the injection molding step;
A sintering process for obtaining a sintered body by sintering the molded body degreased by the degreasing process;
A film forming step of forming a film of a triazine dithiol derivative on the surface of the sintered body obtained in the sintering step;
It is set as the structure provided with the insert molding process which insert-molds a resin material with a molding machine with respect to the sintered compact in which the film layer of the triazine dithiol derivative was formed in the surface at the film formation process.

  Thereby, first, a sintered body of a metal material is obtained. In the present invention, a sintered body of a metal material is formed by a metal injection molding method, so-called “MIM (Metal Injection Molding)” method. In this method, in a mixing step, a binder (binder) that imparts fluidity to the metal powder, such as resin or wax, is added, and heated and kneaded to impart plasticity. Next, in the injection molding step, a molded body is obtained by injection molding in the same manner as plastic. Thereafter, the binder is removed (degreasing) in the degreasing step, and the formed body is sintered in the sintering step to obtain a desired sintered body.

Next, in the film forming step, a film of the triazine dithiol derivative is formed on the surface of the sintered body. In this film forming step, as described above, for example, a film layer of a triazine dithiol derivative is formed by a known method such as an electric field polymerization method or an immersion method.
In the insert molding process, the resin material is injected and insert-molded onto the sintered body by a known insert molding machine. At this time, when the molten resin material is injected into the mold cavity filled with the metal material, the resin material is bonded to the metal material via the triazine dithiol derivative. In this case, since the resin material enters the pores on the surface of the sintered body and is joined to the metal material via the triazine dithiol derivative, the joining is further strengthened. Therefore, the bonding strength with the resin material can be improved only by forming the coating layer of the triazine dithiol derivative regardless of the type of the metal material, and the production efficiency can be improved. In addition, since the metal material and the resin material are joined directly rather than through the aluminum mixed layer as in the past, the accuracy can be improved, and it can contribute to the manufacture of precision parts. become. In particular, it is effective for ferrous metals.

  Moreover, it is set as the structure which performs the said degreasing process and a sintering process continuously in a degreasing sintering furnace as needed. Compared to the case of putting in a degreasing furnace and degreasing, then taking out the molded product, putting it in a sintering furnace and sintering it, degreasing and sintering are performed continuously in one degreasing and sintering furnace. The production efficiency is greatly improved since the sintering is completed in a short time.

Furthermore, if necessary, the sintering temperature Ts in the sintering step is configured such that Ts <Tm when the melting temperature Tm of the metal material is set. Thereby, sintering is performed.
In this case, when the sintering temperature Ts in the sintering step is the melting point temperature Tm of the metal material, Ts = (0.70-0.90) Tm can be obtained.
Generally, in the MIM method, the sintering temperature Ts is as close to the melting point temperature Tm as possible, for example, Ts = (0.91 to 0.98) Tm is standard, but in the present invention, the strength of the sintered body is impaired. If the temperature is low, Ts = (0.70-0.90) Tm can be set relatively low. Thereby, since the porous property of a sintered compact is ensured, the coupling | bonding with a resin material is securable. Further, since the sintering temperature can be set relatively low, labor saving can be achieved.

  According to the present invention, since the metal material is a sintered body manufactured by the so-called MIM method, the metal material is porous. When a coating layer of a triazine dithiol derivative is formed on the surface of the sintered body, the sintered material is sintered. The triazine dithiol derivative enters the pores on the surface of the body, and when the injection molding is performed in the injection molding apparatus, the resin material also enters the pores on the surface of the sintered body and joins with the metal material via the triazine dithiol derivative. Bonding becomes stronger. Therefore, the bonding strength with the resin material can be improved only by forming the coating layer of the triazine dithiol derivative regardless of the type of the metal material, and the production efficiency can be improved. As a result, the metal material and the resin material are directly bonded only through the film layer of the triazine dithiol derivative, so that the accuracy can be improved and the production of precision parts can be contributed. In particular, it is effective for ferrous metals such as stainless steel.

It is sectional drawing which shows the insert molded product which concerns on embodiment of this invention. It is process drawing which shows the manufacturing method of the insert molded product which concerns on embodiment of this invention. It is a figure which shows the shape of the test piece of the insert molded product which concerns on the Example of this invention, (a) is a top view, (b) is a front view, (c) is front sectional drawing. It is a table | surface figure which shows the result of the manufacturing conditions and the adhesive strength test about Example 1 thru | or 8 of this invention. It is an electron micrograph of the surface of the sintered compact (metal material) used in Example 1, 3, and 7 of this invention. It is an electron micrograph of the surface of the sintered compact (metal material) used in Examples 2, 4, and 8 of the present invention. It is an electron micrograph of the surface of the stainless steel material which concerns on a comparative example. It is a microscope picture which shows the planar state of the fracture | rupture part by the side of the metal material after the resin material fracture | ruptures in Example 5 of this invention. It is a microscope picture which shows the planar state of the fracture | rupture part by the side of the metal material after the resin material fracture | ruptures in Example 6 of this invention. It is a microscope picture which shows the planar state of the fracture | rupture part by the side of the metal material after the resin material fracture | ruptures in Example 7 of this invention. It is a microscope picture which shows the cross-sectional state of the fracture | rupture part by the side of the metal material after the resin material fracture | ruptures in Example 7 of this invention.

Hereinafter, an insert molded product and an insert molded product manufacturing method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
As shown in FIG. 1, an insert molded product S according to an embodiment of the present invention is obtained by joining a resin material R to a metal material M having a coating layer F of a triazine dithiol derivative formed on the surface thereof by insert molding. is there. And the metal material M is comprised with the sintered compact manufactured by the metal injection molding method.

The metal material M may be any metal or alloy as described above. In the embodiment, the metal material M is made of, for example, stainless steel (SUS) that is an iron-based metal.
The resin material R can also be selected from various resins as described above. In the embodiment, the resin material R is made of, for example, polyamide (PA resin) or polyphenylene sulfide (PPS resin). These resins are heat-resistant engineering plastics, have excellent chemical resistance and flame resistance, and are widely used mainly in automobiles, electrical / electronics and precision machine parts.

  Next, a method for manufacturing the insert molded product S according to the embodiment of the present invention will be described. As shown in FIG. 2, this manufacturing method includes (1) a mixing step, (2) an injection molding step, (3) a degreasing step, and (4) a metal injection molding method (so-called “MIM” method). Thus, a sintered body of the metal material M is manufactured. Next, in the film forming step, a coating layer F of a triazine dithiol derivative is formed on the surface of the sintered body. Finally, (6) In the insert molding step, the resin material R is joined to the sintered body by insert molding. Hereinafter, each step will be described.

(1) Mixing step A stainless steel (SUS) metal powder and a binder (binder) such as wax are mixed to obtain a mixture. The metal powder has a particle size of about 10 μm, for example. These materials are put into a material kneader (kneader) and heated and kneaded. Then pelletize.

(2) Injection molding process In a metal injection molding machine, the pelletized mixture is injection molded and formed into a molded body having a required shape.

(3) Degreasing process It puts into a degreasing sintering furnace, and degreasing | defatting is first performed in 300 degreeC atmosphere first, for example. Thereby, the degreasing process of the binder of a molded object is performed.

(4) Sintering process Next, in a degreasing sintering furnace, the degreased shaped body is sintered to obtain a sintered body. At the melting point temperature Tm (1350 ° C. to 1550 ° C.) of stainless steel (SUS), the sintering temperature Ts is set to Ts <Tm. In this case, the sintering temperature Ts can be Ts = (0.70-0.90) Tm. For example, when Ts ≦ 0.86 Tm and the melting point temperature Tm = 1400 ° C., in the MIM method, the sintering temperature Ts is as close as possible to the melting point temperature Tm, for example, Ts = 1350 ° C. (= 0.97 Tm) is standard. However, Ts = 1200 ° C. (= 0.86 Tm) and Ts = 1050 ° C. (= 0.75 Tm) can be set relatively low. Thereby, since the porosity of a sintered compact is ensured, the coupling | bonding with the resin material R is securable. Further, since the sintering temperature can be set relatively low, labor saving can be achieved.

  Moreover, since this sintering process is performed continuously with the degreasing process in one degreasing sintering furnace, the degreasing process is performed in the degreasing furnace, and then the molded product is taken out and then placed in the sintering furnace for sintering. In comparison, the number of work steps is reduced, and the sintering is completed in a short time, so that the production efficiency is greatly improved.

(5) Film forming step A film of a triazine dithiol derivative is formed on the surface of the sintered body. In the embodiment, the electropolymerization processing method is used. In the electropolymerization method, an electrolytic solution in which a triazine dithiol derivative is dissolved in water or an organic solution together with an electrolyte substance is prepared. In an electrolytic bath in which the electrolytic solution is placed, the metal material M is used as an anode, for example, an electrolytic method (organic plating treatment) ) To form a film of the triazine dithiol derivative on the surface of the metal material M while polymerizing the triazine dithiol derivative.

(6) Insert molding process Finally, the resin material R is insert-molded by an insert molding machine with respect to the sintered body on which the coating layer F of the triazine dithiol derivative is formed. At this time, when the molten resin material R is injected into the mold cavity loaded with the metal material M, the resin material R is bonded to the metal material M via the triazine dithiol derivative as shown in FIG. In this case, since the resin material R enters the hole H formed on the surface of the sintered body and is bonded to the metal material M via the triazine dithiol derivative, the bonding is further strengthened. In addition, the bonding strength with the resin material R can be improved only by the formation process of the film layer of the triazine dithiol derivative, and the production efficiency can be improved.

  According to the insert molded product S manufactured in this way, the metal material M and the resin material R are firmly bonded, so that the quality can be improved. In addition, since the metal material M and the resin material R are directly bonded rather than bonded via an aluminum mixed layer as in the past, the accuracy can be improved accordingly, contributing to the manufacture of precision parts. become able to. In particular, it is effective for ferrous metals such as stainless steel (SUS).

  Examples will now be described. As shown in FIG. 3, the insert molded product S according to the embodiment is formed by forming a sintered body of a metal material M into a required shape, and using a plate-like portion provided at one end of the sintered body as a joint portion J. The resin material R is joined by insert molding. As shown in FIG. 4, there are eight types of insert-molded products S according to this example. The metal material M to be used, the sintering temperature Ts of the metal material M, and the conditions of the resin material R are changed, respectively. It was manufactured by the method shown in the above-mentioned embodiment in the same manner except that the melting temperature was changed according to the melting point of the resin material R. As a molding machine, TNS50RE5VE manufactured by Nissei Plastic Industry Co., Ltd. was used. As the metal material M, stainless steel SUS304L (manufactured by Epson Atmix Co., Ltd.) and SUS316L (manufactured by Epson Atmix Co., Ltd.) were used. As the resin material R, PA6 (manufactured by Ube Industries), which is polyamide, PAMXD6 (manufactured by Mitsubishi Engineering Plastics), which is polyamide, and PPS (manufactured by Toray Industries, Inc.) which is polyphenylene sulfide were used. And the sintered compact was manufactured by using the degreasing sintering machine by Shimadzu Mektem Co., Ltd. at any one of 1350 ° C., 1200 ° C. and 1050 ° C.

  And adhesive strength was measured about these 8 types of Examples 1 thru | or 8, respectively. The adhesive strength is determined when each test piece having the shape shown in FIG. 3 is pulled from the metal material M and the resin material R in the longitudinal direction (X direction in the drawing) and the resin material R breaks and is separated from the metal material M. The load was measured, the load was divided by the adhesion area, and the tensile shear strength (MPa) was calculated, which was defined as the adhesion strength. As the measuring instrument, “AGS-10KNB” manufactured by Shimadzu Corporation was used. Ten pieces of each test piece according to each example were prepared, the adhesive strength was measured for all, and an average value was obtained for each example. The results are shown in FIG.

  All showed good adhesive strength. Therefore, it can be seen that the resin material R enters the hole H formed on the surface of the metal material M, and the metal material M and the resin material R are firmly bonded via the triazine dithiol derivative.

  Moreover, the electron micrograph of the surface of the sintered compact used in Examples 1 thru | or 4, 7, and 8 was imaged, and it compared with the surface of the stainless steel material as a comparative example. These electron micrographs are shown in FIGS. The photograph of FIG. 5 is of SUS304L (sintering temperature 1350 ° C.), the photograph of FIG. 6 is of SUS316L (sintering temperature 1350 ° C.), and the photograph of FIG. 7 is a comparative example. As is apparent from the photograph, a large number of holes H of several microns in which the resin material R can enter can be seen in the sintered body.

Further, in Examples 5, 6, and 7, after the resin material R was broken, the broken portion was imaged with an electron microscope, and the state of the resin material R remaining on the metal material M was examined. The results are shown in FIGS. FIG. 8 shows a planar state of Example 5 after fracture. FIG. 9 shows a planar state of Example 6 after fracture. FIG. 10 shows the planar state of Example 7 after fracture. FIG. 11 shows the state of the cross section of Example 7 after fracture.
From this result, it is observed that the density of the holes H formed on the surface is higher when the sintering temperature is lower. In any case, it can be seen that the resin material R well enters the hole H of the metal material M and engages, and the bonding is firmly performed.

  In the above embodiment, the metal material M and the resin material R are not limited to those described above, and may be appropriately selected. Of course, various manufacturing conditions are not limited to the above-described conditions.

S insert molding product M metal material R resin material F coating layer J joint H hole (1) mixing process (2) injection molding process (3) degreasing process (4) sintering process (5) film forming process (6) insert Molding process

Claims (8)

In an insert molded product in which a resin material is joined by insert molding to a metal material formed with a coating layer of a triazine dithiol derivative on the surface,
An insert-molded article, wherein the metal material is a sintered body produced by a metal injection molding method.   The metal material is selected from at least one of iron, copper, aluminum, nickel, gold, silver, platinum, palladium, cobalt, zinc, lead, tin, titanium, chromium, magnesium, manganese, and alloys thereof. The insert-molded article according to claim 1, wherein   The insert-molded article according to claim 2, wherein the metal material is an iron-based metal.   The resin material is polyvinyl chloride, polyethylene, polypropylene, polystyrene, polyvinyl acetate, ABS resin, polyisobutylene, ethylene propylene polymer, polyacrylate ester, polymethacrylate ester, polyacrylonitrile, polycyanoacrylate, polyvinyl ether, Polyvinylidene chloride, polyvinylcarbazole, polyvinylpyrrolidone, polyvinylimidazole, polyisoprene, polybutadiene, butadiene-styrene rubber, butadiene-acrylonitrile rubber, polychloroprene, polyacetal, ethylene propylene diene rubber, polyamide (nylon 6, nylon 66, nylon 11), Polyimide, polyetherimide, silicone resin, silicone rubber, polyurethane, epoxy resin, polyethylene The phthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ketone, polysulfone, polycarbonate, polyether imide, polyether sulfone, and polyethylidene norbornene are selected from any one of claims 1 to 3. Insert molded product. In a method of manufacturing an insert molded product in which a resin material is joined to a metal material having a coating layer of a triazine dithiol derivative formed on the surface by insert molding,
A mixing step of mixing a metal powder and a binder to obtain a mixture;
An injection molding step of molding the mixture obtained in the mixing step into a molded body of a required shape in a metal injection molding machine;
A degreasing step for degreasing the molded body obtained in the injection molding step;
A sintering process for obtaining a sintered body by sintering the molded body degreased by the degreasing process;
A film forming step of forming a film of a triazine dithiol derivative on the surface of the sintered body obtained in the sintering step;
An insert molded product manufacturing method comprising an insert molding step of insert molding a resin material with a molding machine for a sintered body having a coating layer of a triazine dithiol derivative formed on a surface in a film forming step .   6. The method for producing an insert-molded product according to claim 5, wherein the degreasing step and the sintering step are continuously performed in a degreasing sintering furnace.   The method for manufacturing an insert-molded product according to claim 5 or 6, wherein the sintering temperature Ts in the sintering step is Ts <Tm when the melting point temperature Tm of the metal material is set.   The insert molding according to claim 5 or 6, wherein when the sintering temperature Ts in the sintering step is the melting point temperature Tm of the metal material, Ts = (0.70-0.90) Tm. Product manufacturing method.