JP7030510B2 - Manufacturing method of surface roughened magnesium alloy member - Google Patents

Description

The present invention relates to a method for manufacturing a surface-roughened magnesium alloy member.

In recent years, from the viewpoint of global environmental conservation, there has been an active movement to actively utilize magnesium alloys, which are the lightest and most recyclable among practical metals. For example, in the field of automobiles, due to the tendency to reduce the weight of vehicles for the purpose of improving fuel efficiency, studies have begun to apply magnesium alloys to members that used to use steel plates and aluminum alloys. Further, in the field of home appliances, the movement of replacing conventional aluminum alloys with magnesium alloys has become apparent in the housings of notebook computers, mobile phones, and ECU boxes.

With the movement to replace metal materials, in addition to the existing aluminum-resin bonding technology, the technology to bond and integrate magnesium alloys and resins is now available for parts in the automobile field, home appliance field, industrial equipment, etc. It has come to be demanded from a wide range of fields such as the manufacturing field. As a joining means for this purpose, an adhesive is penetrated into an ultrafine uneven shape portion of a surface-roughened magnesium alloy that satisfies a specific surface shape, and a resin member is further adhered to the adhesive layer to produce a magnesium alloy composite. The method is disclosed (for example, Patent Document 1).

The method for roughening the surface of the magnesium alloy proposed in Patent Document 1 is as follows. That is, the surface portion of the magnesium alloy is degreased using a commercially available degreasing agent, and then chemically treated with an aqueous solution of carboxylic acid or mineral acid having a concentration of 1% to several%, preferably an aqueous solution of citric acid, malonic acid, acetic acid, nitric acid or the like. After etching, a smut removal treatment is performed with a basic aqueous solution, and then a chemical conversion treatment is performed. The chemical conversion treatment is a surface treatment performed as a corrosion prevention measure on the surface of a magnesium alloy member that is easily oxidized. In Patent Document 1, magnesium is treated by treating the magnesium alloy member with a weakly acidic aqueous solution of potassium permanganate. A method of coating the surface of an alloy member with a manganese dioxide layer as a chemical conversion coating is described as a preferable form of chemical conversion treatment.

International Publication No. 2008/133096

The inventors of the present application are obtained by bonding a thermoplastic resin to the surface roughening method described in Patent Document 1, the surface roughened magnesium alloy member thus obtained, and the surface roughened magnesium alloy member. We have been diligently studying the mechanical properties of the magnesium alloy / resin composite structure. As a result, when surface roughening is performed according to the roughening method described in Patent Document 1, specifically, the roughening method described in Experimental Example 1, the following problems exist from an industrial point of view. It turned out.

The concept itself of the stepwise chemical solution dipping treatment method described in Patent Document 1, that is, a chemical solution tank containing at least one various chemical solution and a washing tank containing at least one pure water or industrial water. A method and an apparatus for roughening the surface of a metal member by sequentially immersing the metal member to be treated in a plurality of treatment tanks (treatment units) are known.

Here, when the surface treatment is performed with the step of sequentially immersing the magnesium alloy member in a chemical tank or a water tank to complete the total immersion treatment as one cycle, the roughening method described in Patent Document 1 is a magnesium alloy member. As the treatment amount increases, that is, as the number of cycles increases when the surface treatment of the magnesium alloy flat plate is batchwise, or as the continuous treatment time increases when the roll of the coiled magnesium alloy member is continuously surface-treated. The surface of the magnesium alloy member tends to be easily colored brown to dark brown, and such a coloring tendency is caused by repeated renewal work of the chemical tank for chemical etching and / or the chemical tank for chemical treatment, that is, immersion. It was found that even if the frequency of the work of replacing a part or all of the old chemical solution with the new chemical solution was increased, there was no improvement.

When the surface of the surface-roughened magnesium alloy is colored, when the resin member is bonded to the surface of the surface-roughened magnesium alloy to form a magnesium alloy / resin composite structure, the surface-roughened magnesium alloy is formed in the portion where the resin member is not bonded. Since the roughened surface of the above is exposed as it is, there may be a problem in developing the composite structure for applications requiring design and aesthetics. Additional operations such as scraping off this part thinly to regenerate the background in order to eliminate the colored part complicates the entire process, and at the same time, increasing the amount of scraping off also reduces the effective utilization rate of the magnesium alloy material. It is not preferable because it will be connected.

The present invention has been made in view of the above circumstances, and the surface of the surface-roughened magnesium alloy member is colored brown to dark brown even when the amount of the magnesium alloy member to be roughened is increased. It is an object of the present invention to provide a method for manufacturing a surface-roughened magnesium alloy member capable of suppressing the above.

The present inventors have diligently studied the above-mentioned problems and investigated the cause of the above-mentioned coloring. As a result, they have found that the pH of the permanganate aqueous solution in the chemical conversion treatment has a great influence on the coloring of the surface of the surface-roughened magnesium alloy member when the treatment amount of the magnesium alloy member is increased, and reached the present invention.

That is, according to the present invention, the following method for manufacturing a surface-roughened magnesium alloy member is provided.
[1]
A chemical etching process that chemically etches magnesium alloy members with an acidic aqueous solution,
A chemical conversion treatment step for chemical conversion of the chemically etched magnesium alloy member, and
A method for manufacturing a surface-roughened magnesium alloy member containing
The acidic aqueous solution in the chemical etching step contains an organic acid and contains
The surface of the chemical conversion treatment step is characterized in that the chemically etched magnesium alloy member is treated with an aqueous permanganate solution having a pH value measured at 25 ° C. in the range of 3.0 or more and less than 3.7. A method for manufacturing a roughened magnesium alloy member.
[2 ]
The method for producing a surface-roughened magnesium alloy member according to the above [1 ], wherein the permanganate aqueous solution is an aqueous solution in which permanganate is dissolved in an acidic aqueous solution having a pH buffering action.
[ 3 ]
The above-mentioned acidic aqueous solution having a pH buffering action contains at least one selected from acetate, phthalate, citrate, succinate, lactate, tartrate, borate, and phosphate. 1] or [2] , the method for manufacturing a surface-roughened magnesium alloy member.

According to the present invention, even when the treatment amount of the magnesium alloy member to be roughened is increased, it is possible to prevent the surface of the surface roughened magnesium alloy member from being colored brown to dark brown.

It is an external view schematically showing an example of the structure of the magnesium alloy / resin composite structure of the embodiment which concerns on this invention. It is a block diagram which shows typically an example of the process of manufacturing the magnesium alloy / resin composite structure of the embodiment which concerns on this invention. The measurement points of a total of 6 straight lines including any 3 straight lines parallel to each other and any 3 straight lines orthogonal to the 3 straight lines on the surface of the surface-roughened magnesium alloy member according to the present embodiment will be described. It is a schematic diagram for doing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are designated by a common reference numeral, and the description thereof will be omitted as appropriate. Further, the figure is a schematic view and does not match the actual dimensional ratio. Unless otherwise specified, the "~" between the numbers in the text indicates the following from the above.

<Manufacturing method of surface roughened magnesium alloy member>
A method for manufacturing the surface-roughened magnesium alloy member 103 of the present embodiment will be described.
The method for manufacturing the surface-roughened magnesium alloy member 103 according to the present embodiment includes a chemical etching step of chemically etching the magnesium alloy member with an acidic aqueous solution and a chemical etching step of chemically etching the chemically etched magnesium alloy member. include.
Before the chemical etching step, a pretreatment step for the purpose of degreasing or the like may be performed. Further, after the chemical etching step, a chemical conversion treatment step for protecting the etched surface from oxidation is performed.
Further, in the chemical conversion treatment step, the chemically etched magnesium alloy member is treated with a permanganate aqueous solution having a pH value in the range of 3.0 or more and less than 3.7 measured at 25 ° C.
According to the method for manufacturing the surface-roughened magnesium alloy member 103 according to the present embodiment, the surface of the surface-roughened magnesium alloy member 103 is brown to brown even when the treatment amount of the surface-roughened magnesium alloy member is increased. It is possible to suppress coloring to dark brown. Further, by using the surface-roughened magnesium alloy member 103 obtained by the method for producing the surface-roughened magnesium alloy member 103 according to the present embodiment, a magnesium alloy / resin composite structure 106 having excellent bonding strength can be stably obtained. be able to.

In the present embodiment, some additional steps may be optionally performed before and after the above-mentioned pretreatment step, chemical etching step and chemical conversion treatment step. Such optional steps include, for example, a cleaning step with an inorganic acid aqueous solution mainly for the purpose of removing smuts after a chemical etching step, and a neutralization step performed after treatment with an acidic aqueous solution or a basic aqueous solution. And washing process with water. The method for manufacturing the surface-roughened magnesium alloy member 103 according to the present embodiment may be a batch processing method as shown in Examples described later, or a roll made of a coiled magnesium alloy member may be continuously used as a chemical solution. It may be a so-called roll-to-roll method in which the material is passed through a tank, or a hybrid method in which these methods are appropriately combined.
Hereinafter, the (1) pretreatment step, (2) chemical etching step, and (3) chemical conversion post-treatment step of the surface roughening method of the present embodiment will be described in detail in this order.

The magnesium alloy member of the raw material subject to surface roughening in the present embodiment is not particularly limited, but is preferably a magnesium alloy member having a Mn content of 0.5% by mass or less as an alloy component. For example, an alloy member of Mg and rare earth elements such as Al, Zn, Si, Cu, Fe, Mn, Ag, Zr, Sr, Pb, Re, Y and mischmetal can be mentioned. Typical magnesium alloy members include commercially available magnesium alloy members such as AZ91, AZ31, AM60, AM50, AM20, AS41, AS21, and AE42.
The shape of the magnesium alloy member is not particularly limited as long as it can be joined to the resin member 105, and may be, for example, a flat plate shape, a curved plate shape, a coil shape, a rod shape, a tubular shape, a lump shape, or the like. Further, it may be a structure composed of a combination of these.

As the magnesium alloy member, it is preferable that the magnesium alloy material is processed into the above-mentioned predetermined shape by cutting; plastic working by pressing or the like; punching processing; thinning processing such as cutting, polishing, electric discharge machining or the like.

(1) Pretreatment step The magnesium alloy member described above is generally manufactured by a casting method called a die casting method or a thixomolding method, and in some cases, a press molding method or forging using a magnesium alloy plate for wrought. Manufactured by law. Originally, unlike aluminum alloys, magnesium alloy members have a dense hexagonal lattice (HCP) and are not easily deformed. Therefore, a large amount of machine oil, a mold release agent, or the like is often used at the time of molding. As a result, there is a high possibility that a large amount of these oils adhere to and permeate the surface of the magnesium alloy member and contaminate the surface. Therefore, prior to the chemical etching treatment, an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide aqueous solution is used. It is desirable to perform degreasing treatment with a commercially available degreasing agent for magnesium alloys. The degreasing treatment is performed at, for example, 40 to 70 ° C. for several minutes. Further, before the degreasing treatment, a treatment for removing the oxide film or the like deposited on the surface of the magnesium alloy member by mechanical polishing such as sandblasting or grinding or chemical polishing may be performed.

(2) Chemical Etching Step The chemical etching step according to the present embodiment is a step of imparting a fine uneven shape on the surface of a magnesium alloy member. The chemical etching agent (form is an aqueous solution or suspension) used in the chemical etching step is, for example, an acidic aqueous solution containing an organic acid or an inorganic acid. From the viewpoint of the bonding strength between the magnesium alloy member and the resin member, it may be an acidic aqueous solution containing an organic acid or an acidic aqueous solution containing an inorganic acid, but the etching amount is kept to a minimum and is stably high. From the viewpoint of exhibiting bond strength, an acidic aqueous solution containing an organic acid is preferable as the etching agent. The organic acid more preferably contains an aliphatic carboxylic acid. The aliphatic carboxylic acid can be used without limitation as long as it is water-soluble at room temperature, but more preferable aliphatic carboxylic acids include a polybasic acid (a1) having no hydroxy group and one having a hydroxy group. It is classified into three types: a basic acid (a2) and a polybasic acid (a3) having a hydroxy group. Examples of the polybasic acid (a1) having no hydroxy group include oxalic acid, malonic acid, adipic acid, and maleic acid. Examples of the monobasic acid (a2) having a hydroxy group include glycolic acid, lactic acid, glyceric acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, and mevalonic acid. Examples of the polybasic acid (a3) having a hydroxy group include citric acid, malic acid, and tartaric acid. When a polybasic acid is used, a corresponding acid anhydride in which two carboxy groups are formally intramolecularly dehydrated and condensed may be used. This is because acid anhydrides are generally hydrolyzed and converted to dibasic acids by being dissolved in water. Among these aliphatic carboxylic acids, it has a hydroxy group from the viewpoint of roughening efficiency, that is, efficient bonding strength can be stably developed with a minimum etching amount, or from the viewpoint of chemical safety of the etching agent. Polybasic acid (a3) is preferable, and citric acid and tartaric acid are particularly preferably used. Malonic acid is also a preferably used chemical etching agent. At the time of treatment, a magnesium alloy member arbitrarily degreased was placed in an aliphatic carboxylic acid aqueous solution having a concentration of preferably 0.1 to 5% by mass, more preferably 0.5 to 5% by mass. It can be immersed for about 20 minutes, preferably 2 to 15 minutes.

FIG. 3 is for explaining a total of 6 straight lines including any 3 straight lines in parallel on the surface 110 of the surface roughened magnesium alloy member 103 and any 3 straight lines orthogonal to the 3 straight lines. It is a schematic diagram of.
By the above chemical etching, JIS is applied to a total of 6 straight portions consisting of arbitrary 3 straight portions parallel to each other and arbitrary 3 straight portions orthogonal to the 3 straight portions on the surface 110 of the surface-roughened magnesium alloy member 103. A fine concavo-convex structure is formed in which the surface roughness measured in accordance with B0601 (corresponding international standard: ISO4287) simultaneously satisfies the following requirements (1) and (2). For the 6 straight lines, for example, 6 straight lines B1 to B6 as shown in FIG. 3 can be selected. Here, the horizontal distance and the vertical distances D1 to D4 between the straight lines are, for example, 2 to 5 mm.
(1) The average value of the ten-point average roughness (Rz) at an evaluation length of 4 mm is in the range of more than 2.0 μm and 20 μm or less, preferably 3.0 μm or more and 15 μm or less. The average value of the average length (RSm) of the curve element is in the range of more than 10 μm and 200 μm or less, preferably 10 μm or more and 200 μm or less.

After the chemical etching is completed, washing with a weakly basic aqueous solution and / or a strongly basic aqueous solution may be performed, if necessary. Typical examples of such a basic aqueous solution include an aqueous solution of sodium carbonate, an aqueous solution of sodium hydrogen carbonate, or a mixture thereof, and the pH at which 1% by mass of sodium carbonate and 1% by mass of sodium hydrogen carbonate are dissolved is 9. A weakly basic aqueous solution of around 8.8 is preferably used. Further, as the strong basic aqueous solution, for example, a sodium hydroxide aqueous solution of about 15% by mass is used. A washing operation may be performed before and after washing with these weakly basic aqueous solutions and / or basic aqueous solutions.

(3) Chemical conversion treatment step The magnesium alloy member that has undergone the above chemical etching is then subjected to chemical conversion treatment to form a chemical conversion film. That is, since magnesium is a metal having a high ionization tendency, the oxidation rate due to moisture and oxygen in the air is relatively faster than that of other metals. Magnesium alloy members are usually coated with a natural oxide film, but it is not sufficient from the viewpoint of corrosion resistance, and oxidative corrosion progresses due to water molecules and oxygen diffused in the natural oxide film even in a normal environment. .. In order to suppress such an oxidation reaction, a chemical conversion treatment for positively forming a chemical conversion film has been performed so far.

Known chemical conversion treatment methods include a treatment of immersing in a weakly acidic permanganate aqueous solution to cover the entire surface with a thin layer of manganese dioxide, or immersing in an aqueous solution of chromic acid or potassium dichromate to obtain chromium oxide. Generally, corrosion prevention measures are performed by performing chromate treatment (chromate treatment) or the like to cover the entire surface with a thin layer. In the present embodiment, the former method of coating a thin layer of manganese dioxide is preferably used from the viewpoint of environmental pollution.

In the present embodiment, the pH value of the weakly acidic aqueous solution of permanganate measured at 25 ° C. is extremely important for exerting the effect of the present invention. This pH value is 3.0 or more and less than 3.7, preferably 3.1 or more and less than 3.7, more preferably 3.2 or more and 3.6 or less, and further preferably 3.3 or more and 3.6. It is as follows. When the pH of the permanganate aqueous solution satisfies such a range, the number of batch treatments for surface roughening of the magnesium alloy member is repeated, that is, the treatment amount of the magnesium alloy member to be roughened is increased. Further, it is possible to prevent the surface of the surface-roughened magnesium alloy member 103 from being colored brown to dark brown. Examples of the cation species constituting the permanganate include ammonium ion, sodium ion, potassium ion, silver ion and zinc ion, but potassium ion is used because of its safety as a chemical substance and its handleability in the air. This is preferred. The concentration of permanganate in the permanganate aqueous solution is, for example, 0.5 to 5% by mass, preferably 1 to 3% by mass.
When the concentration of permanganate is above the above lower limit, the oxidizing ability becomes better, and when the concentration of permanganate is below the above upper limit, the chemical conversion film is formed while suppressing the amount of permanganate used. The generation speed can be set to an appropriate speed.

The permanganate aqueous solution having a pH value in a specific acidic region as described above is, for example, a permanganate aqueous solution having a pH buffering capacity in the range of 3.0 or more and less than 3.7. Can be easily prepared by dissolving.
As the acidic solution having the pH buffering ability, at least one of acetate, phthalate, citrate, succinate, lactate, tartrate, borate, and phosphate is 0.1 each. Examples thereof include acidic solutions contained in the range of ~ 5.0% by mass. Specifically, acetates such as sodium acetate (CH ₃ COONa), phthalates such as potassium hydrogen phthalate ((KOOC) ₂ C ₆ H ₄ ), sodium citrate (Na ₃ C ₆ H ₅ O ₇ ). And citrates such as potassium dihydrogen citrate (KH ₂ C ₆ H ₅ O ₇ ), succinates such as sodium succinate (Na ₂ C ₄ H ₄ O ₄ ), sodium lactate (NaCH ₃ CHOHCO ₂ ), etc. Contains at least one of tartrates such as lactate, sodium tartrate (Na ₂ C ₄ H ₄ O ₆ ), borates, and phosphates in a concentration range of 0.1 to 5.0% by mass. An aqueous solution can be used.

When the chemically etched magnesium alloy member is treated with a weakly acidic aqueous solution of permanganate, the treatment temperature is, for example, 25 ° C to 60 ° C, preferably 30 ° C to 55 ° C, and the treatment time is 5 seconds to 3 minutes. It is preferably about 10 seconds to 2 minutes. When the treatment temperature is equal to or higher than the above lower limit, it is preferable in the summer because it is not necessary to use additional cooling equipment such as a refrigerator. When the treatment temperature is not more than the above upper limit value, the reaction heat of the permanganate for a short time can be suppressed, which is preferable.

By using the surface-roughened magnesium alloy member 103 obtained by the method for manufacturing the surface-roughened magnesium alloy member 103 according to the present embodiment, the magnesium alloy / magnesium alloy is bonded to the resin member 105, preferably by injection bonding (insert molding). A resin composite structure 106 can be obtained. The resin member 105 is made of a thermoplastic resin composition (P). The thermoplastic resin composition (P) contains a thermoplastic resin (A) as a resin component and, if necessary, a filler (B). Further, the thermoplastic resin composition (P) may optionally contain other compounding agents, if necessary.

(Thermoplastic resin (A))
The thermoplastic resin (A) is not particularly limited, and for example, a polyolefin resin, a polymethacrylic resin such as polymethylmethacrylate resin, a polyacrylic resin such as methylpolyacrylate resin, a polystyrene resin, and a polyvinyl alcohol-poly. Vinyl chloride copolymer resin, polyvinyl acetal resin, polyvinyl butyral resin, polyvinyl formal resin, polymethylpentene resin, maleic anhydride-styrene copolymer resin, polycarbonate resin, polyphenylene ether resin, polyether ether ketone resin, polyether ketone Aromatic polyether ketones such as resins, polyester resins, polyamide resins, polyamideimide resins, polyimide resins, polyetherimide resins, styrene elastomers, polyolefin elastomers, polyurethane elastomers, polyester elastomers, polyamide elastomers, ionomers , Aminopolyacrylamide resin, isobutylene anhydride copolymer, ABS, ACS, AES, AS, ASA, MBS, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-vinyl chloride graft polymer, ethylene-vinyl alcohol Copolymer, chlorinated polyvinyl chloride resin, chlorinated polyethylene resin, chlorinated polypropylene resin, carboxyvinyl polymer, ketone resin, amorphous copolyester resin, norbornen resin, fluoroplastic, polytetrafluoroethylene resin, fluorinated ethylene polypropylene resin , PFA, polychlorofluoroethylene resin, ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride resin, polyvinyl fluoride resin, polyallylate resin, thermoplastic polyimide resin, vinylidene chloride resin, polyvinyl chloride resin, vinyl acetate resin, polysulphon Resin, polyparamethylstyrene resin, polyallylamine resin, polyvinyl ether resin, polyphenylene oxide resin, polyphenylene sulfide (PPS) resin, polymethylpentene resin, oligoester acrylate, xylene resin, maleic acid resin, polyhydroxybutyrate resin, polysulfone Examples thereof include resins, polylactic acid resins, polyglutamic acid resins, polycaprolactone resins, polyether sulfone resins, polyacrylonitrile resins, styrene-acrylonitrile copolymer resins and the like. These thermoplastic resins (A) may be used alone or in combination of two or more.

Among these, the thermoplastic resin (A) includes a polyolefin resin, a polyester resin, and a polyester resin from the viewpoint of more effectively obtaining the effect of improving the bonding strength between the surface roughened magnesium alloy member 103 and the resin member 105. One or more thermoplastic resins selected from polyamide resins are preferably used.

(Filler (B))
The thermoplastic resin composition (P) further comprises a filler (B) from the viewpoint of adjusting the difference in linear expansion coefficient between the surface-roughened magnesium alloy member 103 and the resin member 105 and improving the mechanical strength of the resin member 105. It may be included.
As the filler (B), for example, one or more kinds can be selected from the group consisting of glass fiber, carbon fiber, carbon particles, clay, talc, silica, mineral, and cellulose fiber. Of these, one or more selected from glass fiber, carbon fiber, talc, and minerals are preferable.

When the thermoplastic resin composition (P) contains the filler (B), the content thereof is preferably 1 part by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin (A). , More preferably 5 parts by mass or more and 70 parts by mass or less, and particularly preferably 10 parts by mass or more and 50 parts by mass or less.

(Other compounding agents)
The thermoplastic resin composition (P) may contain other compounding agents for the purpose of further imparting a unique function other than mechanical strength. Examples of such a compounding agent include heat stabilizers, antioxidants, pigments, weather resistant agents, flame retardants, plasticizers, dispersants, lubricants, mold release agents, antistatic agents and the like. When the thermoplastic resin composition (P) contains other compounding agents, the content thereof is preferably 0.0001 to 5 parts by mass with respect to 100 parts by mass of the thermoplastic resin (A), which is more preferable. Is 0.001 to 3 parts by mass.

As a method for producing the magnesium alloy / resin composite structure 106 according to the present embodiment, that is, a method for joining the resin member 105 made of the thermoplastic resin composition (P) to the surface roughened magnesium alloy member 103, for example, injection molding. , Extrusion molding, heat press molding, compression molding, transfer molding, casting molding, laser welding molding, reaction injection molding (RIM molding), rim molding (LIM molding), spray molding and other resin molding methods.
Among these, the injection molding method is preferable, and specifically, injection molding in which the surface-roughened magnesium alloy member 103 is inserted into the cavity of the injection molding mold and the thermoplastic resin composition (P) is injected into the mold. It is preferable to mold the resin member 105 by the method to produce the magnesium alloy / resin composite structure 106. Hereinafter, a specific description will be given.

FIG. 2 is a block diagram schematically showing an example of a process of manufacturing the magnesium alloy / resin composite structure 106 according to the embodiment of the present invention.
The method for producing the magnesium alloy / resin composite structure 106 according to the present embodiment includes, for example, the following steps [1] to [3].
[1] Step of preparing a desired thermoplastic resin composition (P) [2] Step of installing a surface-roughened magnesium alloy member 103 including a concavo-convex forming region inside a mold 102 for injection molding [3] Heat A step of injection molding the plastic resin composition (P) into the mold 102 through an injection molding machine 101 so as to be in contact with at least an uneven formation region of the surface roughened magnesium alloy member 103 to form the resin member 105.

Hereinafter, the injection molding method according to the steps [2] and [3] will be described.
First, a mold 102 for injection molding is prepared, the mold is opened, and a surface-roughened magnesium alloy member 103 including a concavo-convex forming region is installed in a part of the mold 102.
After that, the mold 102 is closed, and the step [1] is performed in the mold 102 so that at least a part of the thermoplastic resin composition (P) is in contact with the uneven shape forming region of the surface 110 of the surface roughened magnesium alloy member 103. The thermoplastic resin composition (P) obtained in 1 is injected and solidified. After that, the magnesium alloy / resin composite structure 106 can be obtained by opening the mold 102 and releasing the mold.

Further, in addition to the injection molding by the above steps [1] to [3], injection foam molding or high-speed heat cycle molding (RHCM, heat & cool molding) for rapidly heating and cooling the mold 102 may be used in combination. good.
As a method of injection foam molding, a method of adding a chemical foaming agent to a resin, a method of directly injecting nitrogen gas or carbon dioxide gas into the cylinder of an injection molding machine, or a method of injecting nitrogen gas or carbon dioxide gas in a supercritical state. There is a MuCell injection foam molding method of injecting into the cylinder portion of a molding machine, and any method can obtain a magnesium alloy / resin composite structure 106 in which the resin member 105 is a foam. Further, in any of the methods, it is possible to use counter pressure or a core back depending on the shape of the molded product as a control method of the mold 102.
High-speed heat cycle molding can be carried out by connecting a rapid heating / cooling device to the mold 102. The rapid heating / cooling device may be a generally used method. As the heating method, any one of steam type, pressurized hot water type, hot water type, hot oil type, electric heater type, electromagnetic induction superheating type, or a method in which a plurality of them are combined can be used. As the cooling method, either one of the cold water type and the cold oil type or a method in which they are combined can be used. As a condition of the high-speed heat cycle molding method, for example, the mold 102 for injection molding is heated to a temperature of 100 ° C. or higher and 250 ° C. or lower, and after the injection of the thermoplastic resin composition (P) is completed, it is used for injection molding. It is desirable to cool the mold 102 of. The preferred range of the temperature for heating the mold differs depending on the thermoplastic resin (A) constituting the thermoplastic resin composition (P), and if the thermoplastic resin is a crystalline resin and has a melting point of less than 200 ° C, it is 100 ° C. It is preferably 150 ° C. or higher, and if it is a crystalline resin and a thermoplastic resin having a melting point of 200 ° C. or higher, 140 ° C. or higher and 250 ° C. or lower is desirable. The amorphous resin is preferably 100 ° C. or higher and 180 ° C. or lower.

The magnesium alloy / resin composite structure 106 according to the present embodiment is used in various industrial fields by taking advantage of its high bonding strength and light weight even under harsh conditions. For example, the personal computer field represented by the bottom case and liquid crystal rear case of a laptop computer; the mobile phone field such as a thin-walled housing for a mobile phone and the frame body; the camera field such as a cover and a mirror box for a digital single-lens reflex camera; a speaker Audio field such as vibration plate; Second hand of clock; Automotive field such as automobile head cover, oil pan, cylinder block, steering wheel, steering member, mission case, seat back frame, road wheel; Motorcycle engine field; Aircraft engine parts, helicopter The field of aviation such as gearboxes; the field of railway vehicles; the field of tools such as lightweight pliers and lightweight hammers; the field of sports such as yoyo for competition can be mentioned.

The uses of the magnesium alloy / resin composite structure 106 according to the present embodiment have been described above, but these are examples of the uses of the present embodiment and can be used for various uses other than the above.

Although the embodiments of the present invention have been described above, these are examples of the present invention and include various configurations other than the above.
Hereinafter, an example of the embodiment will be added.
1. 1. A chemical etching process that chemically etches magnesium alloy members with an acidic aqueous solution,
A chemical conversion treatment step for chemical conversion of the chemically etched magnesium alloy member, and
A method for manufacturing a surface-roughened magnesium alloy member containing
The surface of the chemical conversion treatment step is characterized in that the chemically etched magnesium alloy member is treated with an aqueous permanganate solution having a pH value measured at 25 ° C. in the range of 3.0 or more and less than 3.7. A method for manufacturing a roughened magnesium alloy member.
2. 2. 1. The acidic aqueous solution in the chemical etching step contains an organic acid. A method for manufacturing a surface-roughened magnesium alloy member according to.
3. 3. The permanganate aqueous solution is an aqueous solution in which permanganate is dissolved in an acidic aqueous solution having a pH buffering action. Or 2. A method for manufacturing a surface-roughened magnesium alloy member according to.
4. 1. The acidic aqueous solution having a pH buffering action contains at least one selected from acetate, phthalate, citrate, succinate, lactate, tartrate, borate, and phosphate. To 3. The method for manufacturing a surface-roughened magnesium alloy member according to any one of the above.

Hereinafter, this embodiment will be described in detail with reference to Examples and Comparative Examples. The present embodiment is not limited to the description of these examples.

[Example 1]
(Surface roughening)
The magnesium alloy plate AZ31B (thickness: 2.0 mm) was cut into a length of 45 mm and a width of 18 mm to prepare a total of 500 flat magnesium alloy plates. Next, the intermediate treated body C was prepared by performing the following treatments on the magnesium alloy plates one by one.
First, the magnesium alloy plate was immersed in a 7.5 mass% aqueous solution of a commercially available degreasing agent for magnesium alloy "Cleaner 160 (manufactured by Meltex Inc.)" at 60 ° C. for 5 minutes, and then washed with water. Then, it was immersed in a citric acid aqueous solution tank having a citric acid concentration of 1% by mass at 40 ° C. for 4 minutes for chemical etching, and then ultrasonically washed with water at room temperature for 2 minutes. Then, for the purpose of removing smut, it was immersed in a mixed aqueous solution of sodium carbonate / sodium hydrogencarbonate at 65 ° C. (sodium carbonate concentration; 1% by mass, sodium hydrogencarbonate concentration; 1% by mass, pH; 9.8) for 5 minutes. .. Then, it was immersed in a 15 mass% sodium hydroxide aqueous solution at 65 ° C. for 5 minutes and then washed with water to obtain an intermediate treatment body C. Here, the degreasing agent aqueous solution in the degreasing tank, the sodium carbonate / sodium hydrogen carbonate mixed aqueous solution in the smut removing tank, the sodium hydroxide aqueous solution in the smut removing tank, the citric acid aqueous solution in the citric acid aqueous solution tank, and the water in the washing tank. Every time the treatment for 10 sheets of the magnesium alloy plate was completed, a newly prepared chemical solution was used.
The intermediate processed bodies C of the 1st, 10th, 30th, 100th, 200th, 300th, 400th and final 500th sheets were sampled, and their surface roughness was measured in Tokyo. The measurement was performed with a surface roughness measuring device "Surfcom 1400D" manufactured by Seimitsu Co., Ltd. As a result, the ten-point average roughness (Rz) average value is unevenly distributed in the range of 3 μm to 7 μm for all the treated plates, and the average value of the average length (RSm) of the roughness curve elements is in the range of 70 μm to 100 μm. It was confirmed that it was unevenly distributed in. From this result, it is presumed that in the chemical etching step, a fine uneven structure is formed under substantially the same acid conditions.

Next, one intermediate treatment body C after completing the above chemical etching and smut removal operations was immersed in an aqueous solution of potassium permanganate having a pH of 3.3 measured at 25 ° C. at 35 ° C. for 1 minute, and then at room temperature. The surface-roughened product A1 was obtained by ultrasonically washing with water for 5 minutes and then drying in a warm air dryer. Here, the pH of the potassium permanganate aqueous solution of pH 3.3 measured at 25 ° C. was adjusted to 3.3 (measured at 25 ° C.) by adding acetic acid to a 0.5 mass% sodium acetate trihydrate aqueous solution. It was prepared by dissolving 2% by mass of potassium permanganate in a buffered acetic acid / sodium acetate aqueous solution.

This series of cycle operations is repeated 350 times by changing the intermediate treatment body C to a new one, and the 100th surface roughening body A100 and the 200th surface roughening body A200 and the 350th surface roughening body in the middle are repeated. The embodiment A350 was secured. The pH of the potassium permanganate aqueous solution after preparing the surface roughened body 350 was 3.6.

Five points were arbitrarily selected from the roughened surfaces of the surface roughened body A1, the surface roughened body A100, the surface roughened body A200, and the surface roughened body A350, and the color tone was visually observed. As a result, the color tone of 5 points was bright yellow for all the roughened bodies.

(injection molding)
The obtained surface roughened body A1, surface roughened body A100, surface roughened body A200, and surface roughened body 350 were placed in a small dumbbell metal insert mold 102 mounted on J55AD-30H manufactured by Japan Steel Works, Ltd. Each was installed. Next, a PBT resin (Duranex 930HL) manufactured by Polyplastics Co., Ltd., which is a resin composition (P), is placed in a mold 102 under the conditions of a cylinder temperature of 270 ° C., a mold temperature of 160 ° C., an injection primary pressure of 90 MPa, and a holding pressure of 80 MPa. A magnesium alloy / resin composite structure A1, a magnesium alloy / resin composite structure A100, a magnesium alloy / resin composite structure A200, and a magnesium alloy / resin composite structure A350 were obtained by injection molding.

Using the tensile tester "Model 1323 (manufactured by Aiko Engineering Co., Ltd.)", attach a special jig to the tensile tester, and at room temperature (23 ° C), the chuck distance is 60 mm and the tensile speed is 10 mm / min. The joint strength was measured. The joint strength was obtained by dividing the breaking load (N) by the area of the magnesium alloy / resin joint portion. The measurement was performed on 5 samples, and the average value thereof was taken as the joint strength ( _SA ). The bonding strengths _SA1 , _SA100 , _SA200 and SA350 of the magnesium alloy / resin composite structure A1, the magnesium alloy / resin composite structure A100, the magnesium alloy / resin composite structure A200 and the magnesium alloy / resin composite structure _A350 are , 31 MPa, 31 MPa, 31 MPa and 31 MPa, respectively. The fracture surface was the fracture of the resin base material.

[Comparative Example 1]
A single intermediate treatment body C was formed in the same manner as in Example 1 except that an aqueous solution of potassium permanganate having a pH of 3.7 measured at 25 ° C. was used instead of the aqueous solution of potassium permanganate having a pH of 3.3. The treatment was carried out to obtain a surface roughened body B1. Here, the pH 3.7 aqueous potassium permanganate solution measured at 25 ° C. is acetic acid / acetic acid / trihydrate aqueous solution prepared by adding acetic acid to buffer the pH to 3.7 (measured at 25 ° C.). It was prepared by dissolving potassium permanganate in an aqueous solution of sodium acetate. Here, in the potassium permanganate aqueous solution having a pH of 3.7 measured at 25 ° C., the concentration of sodium acetate / trihydrate was 0.5% by mass, the concentration of acetic acid was 1% by mass, and the concentration of potassium permanganate was. 2% by mass. The potassium permanganate aqueous solution having a pH of 3.7 corresponds to the potassium permanganate aqueous solution disclosed in Experimental Example 1 of International Publication No. 2008/133096.

This series of cycle operations was repeated 100 times to secure the 40th surface roughened body B40 and the 100th surface roughened body B100 on the way. The pH of the potassium permanganate aqueous solution after preparing the surface roughened body B100 had risen to 4.2.

For the surface roughened body B1, the surface roughened body B40, and the surface roughened body B100, 5 points were arbitrarily selected from the roughened surfaces and the surface color tone was visually observed. As a result, all 5 points of the surface roughened body B1 were bright yellow, 4 points out of 5 points of the surface roughened body B40 were brown, the remaining 1 point was light brown, and 5 points of the surface roughened body B100. Everything was dark brown.

(injection molding)
PBT resin (Duranex 930HL) manufactured by Polyplastics Co., Ltd. is injection-molded on the obtained surface roughened body B1, surface roughened body B40, and surface roughened body B100 under the same conditions as those of the injection molding of Example 1. Then, a magnesium alloy / resin composite structure B1, a magnesium alloy / resin composite structure B40, and a magnesium alloy / resin composite structure B100 were obtained, respectively.

Next, for the magnesium alloy / resin composite structure B1, the magnesium alloy / resin composite structure B40, and the magnesium alloy / resin composite structure _B100 , the bonding strengths SB1, _SB40 , and _SB100 are the same as in the method described in Example 1. Asked. As a result, _SB1 , _SB40 and _SB100 were 31 MPa, 28 MPa and 26 MPa, respectively.

101 Injection molding machine 102 Mold 103 Surface roughened magnesium alloy member 104 Joint surface (surface treatment area)
105 Resin member 106 Magnesium alloy / resin composite structure 107 Gate / Runner 110 Surface of surface roughened magnesium alloy member

Claims (3)

A chemical etching process that chemically etches magnesium alloy members with an acidic aqueous solution,
A chemical conversion treatment step for chemical conversion of the chemically etched magnesium alloy member, and
A method for manufacturing a surface-roughened magnesium alloy member containing
The acidic aqueous solution in the chemical etching step contains an organic acid and contains
The surface of the chemical conversion treatment step is characterized in that the chemically etched magnesium alloy member is treated with an aqueous permanganate solution having a pH value measured at 25 ° C. in the range of 3.0 or more and less than 3.7. A method for manufacturing a roughened magnesium alloy member. The method for producing a surface-roughened magnesium alloy member according to claim 1, wherein the permanganate aqueous solution is an aqueous solution in which permanganate is dissolved in an acidic aqueous solution having a pH buffering action. Claimed that the acidic aqueous solution having a pH buffering action contains at least one selected from acetate, phthalate, citrate, succinate, lactate, tartrate, borate, and phosphate. The method for producing a surface-roughened magnesium alloy member according to 1 or 2 .

Images