JP6318001B2 - Method for producing molded body having plated film - Google Patents

Description

  The present invention relates to a method for producing a molded body having a plating film.

  An electroless plating method is known as a method for forming a metal film on a molded body at low cost. In the electroless plating method, a pretreatment for roughening the surface of the molded body is performed using an etching solution containing an oxidizing agent such as hexavalent chromic acid or permanganic acid in order to ensure adhesion of the metal film to the molded body. Therefore, an ABS resin (acrylonitrile / butadiene / styrene copolymer synthetic resin) that is eroded by an etching solution has been mainly used in the electroless plating method. In the ABS resin, the butadiene rubber component is selectively eroded by the etching solution, and irregularities are formed on the surface. On the other hand, for a resin other than the ABS resin, for example, polycarbonate, a plating grade in which a component that is selectively oxidized to an etching solution such as an ABS resin or an elastomer is mixed in order to enable electroless plating. However, such pretreatment of the electroless plating method has a problem of high environmental load because hexavalent chromic acid or the like is used.

  On the other hand, as a method for forming a metal film on a molded body without passing through the pretreatment etching step, use of a surface modification method of the molded body using pressurized carbon dioxide such as supercritical carbon dioxide has been proposed. Yes. The present inventors have proposed a method of performing surface modification treatment using pressurized carbon dioxide at the same time as injection molding, and dispersing palladium serving as a catalyst core for electroless plating near the surface of the molded body (patent) Literatures 1-3). In this method, a plating film can be formed on the surface of the molded body without performing an etching step by performing electroless plating on the molded body having palladium unevenly distributed on the surface.

Japanese Patent No. 4160623 Japanese Patent No. 3696878 JP 2010-30106 A

  When the electroless plating solution is brought into contact with the molded body containing the catalyst described in Patent Documents 1 to 3, the plating solution penetrates from the surface of the molded body into contact with the metal fine particles, and the inside of the molded body. The plating film grows while spreading the molded body. For this reason, the plating film has high adhesion strength.

  On the other hand, there are various uses of the molded body having a plated film. For example, in decorative applications, not only the adhesion strength of the plated film but also a high quality appearance is required. In particular, it has been difficult to form a uniform plating film having excellent appearance characteristics in a complex-shaped molded body or a molded body containing mineral.

  The present invention solves these problems and provides a method for producing a molded body having a plating film having high adhesion strength as an initial characteristic and excellent appearance characteristics.

According to the present invention, there is provided a method for producing a molded body having a plating film, comprising producing a first resin pellet containing a block copolymer containing a hydrophilic segment and metal fine particles, and a first resin pellet. And molding the molded body by plasticizing and melting the second resin pellet containing mineral and polyamide, contacting the molded body with a strong acid for 1 to 30 seconds, and molding the molded article in contact with the strong acid body contacting the electroless plating solution, it viewed including forming a plating film, is possible to manufacture the first resin pellets and melting plasticizing the block copolymers was melt the plasticizing Mixing the block copolymer with pressurized carbon dioxide in which the metal fine particles are dissolved, extruding the block copolymer in which the metal fine particles and pressurized carbon dioxide are mixed, and the extrusion There is provided a method for producing a molded body having a plated film, comprising pulverizing a molded block copolymer to obtain the first resin pellet .

  In the present invention, the mineral may contain at least one of lead and sulfur. The strong acid may be hydrochloric acid, nitric acid, sulfuric acid, perchloric acid, hydrobromic acid, hydroiodic acid, chromic acid, chloric acid, bromic acid, iodic acid, perbromic acid, metaperiodic acid, permanganic acid. , At least one selected from the group consisting of thiocyanic acid, tetrafluoroboric acid and hexafluorophosphoric acid, or hydrochloric acid or nitric acid.

  You may make a strong acid contact the said molded object for 5 to 30 seconds. Moreover, 1.0-3.5N may be sufficient as the density | concentration of the said strong acid, and 1.0-3.0N may be sufficient as it. 10-30 degreeC may be sufficient as the temperature of the said strong acid.

  In the present invention, the mineral is selected from the group consisting of calcium silicate, aluminum silicate, magnesium silicate, silicon dioxide, calcium oxide, calcium carbonate, magnesium oxide, magnesium hydroxide, barium sulfate and compounds containing these. At least one of at least one of lead and sulfur may be included, and the mineral may include at least one of calcium oxide and silicon dioxide and at least one of lead and sulfur. The mineral may be a natural mineral. The shape of the mineral may be granular.

  In the present invention, the surface roughness (Ra) of the molded body may be 1 μm or less. The strong acid may not contain hexavalent chromic acid.

  In this invention, before making the said electroless-plating liquid contact the said molded object, you may include making an alcohol process liquid contact further to the said molded object. Moreover, after making the said strong acid contact the said molded object, you may make the said alcohol treatment liquid contact the said molded object.

  In the present invention, the alcohol treatment liquid may soften the block copolymer. The alcohol treatment liquid is ethanol, 1-propanol, 2-propanol, 1,2-butanediol, 1,3-butanediol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 1- Ethoxy-2-propanol, 2-methyl-2,4-pentanediol, 2- (2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethanol, 2- (2-methoxyethoxy) ethanol, ethylene glycol, At least one selected from the group consisting of diethylene glycol, tetraethylene glycol, polyethylene glycol, and polypropylene glycol may be included, and the alcohol treatment liquid may include 1,3-butanediol.

  In the present invention, the hydrophilic segment of the block copolymer may be a polyether. The metal fine particles may contain palladium.

  The present invention performs a pretreatment for plating using a strong acid on a molded body containing a thermoplastic resin containing polyamide, a mineral, a block copolymer containing a hydrophilic segment, and metal fine particles, The plating reactivity of the molded product can be improved. Thereby, while having high adhesive strength, the molded object which has a plating film which is excellent also in an external appearance characteristic can be manufactured.

FIG. 1 is a flowchart illustrating a method for manufacturing a molded body having a plating film manufactured in the embodiment. FIG. 2 is a schematic view of the resin pellet manufacturing apparatus used in the examples. FIG. 3 (a) is a scanning electron microscope (SEM) photograph of a plating film non-adhered portion produced at the stage of forming an electroless nickel phosphorus plating film in the molded body produced in Comparative Example 1, (b) Is an SEM photograph of the cross section of the plating film non-attached portion, and (c) is an SEM photograph of the cross section of the plating film forming portion.

  A method for producing a molded body having a plating film will be described with reference to FIG. First, a molded body containing a thermoplastic resin containing polyamide, a mineral, a block copolymer containing a hydrophilic segment, and metal fine particles is prepared (FIG. 1, step S1).

[Molded body]
The molded body contains polyamide as a thermoplastic resin. Since polyamide has high water absorption, penetration of the plating solution is promoted and the plating film grows stably. Moreover, since polyamide is excellent in rigidity, heat resistance and chemical resistance, the rigidity, heat resistance and chemical resistance of resin parts can be ensured. The polyamide contained in the thermoplastic resin is not particularly limited, and nylon 6 (PA6), nylon 66 (PA66), nylon 12 (PA12), nylon 11 (PA11), nylon 6T (PA6T), nylon MXD6 (PAMDX6) Nylon 6.66 copolymer or the like can be used. Nylon 6 which has high water absorption and easily swells is preferable because of the ease of forming a plating film. The thermoplastic resin of the molded body is preferably a polyamide as a main component. For example, the polyamide is preferably contained in the thermoplastic resin in an amount of 30% by weight to 100% by weight, and 60% by weight to 98% by weight. Is more preferable.

  The thermoplastic resin of the molded body may or may not contain a resin other than polyamide. The resin other than polyamide is not particularly limited, but is polypropylene, polymethyl methacrylate, polycarbonate, amorphous polyolefin, polyetherimide, polyethylene terephthalate, polyethylene ether ketone, ABS resin, polyphenylene sulfide, polyamideimide, polylactic acid, polycaprolactone. Etc. can be used.

  The content of the thermoplastic resin in the molded body is better from the viewpoint of the mechanical strength of the molded body. On the contrary, from the viewpoint of the electroless plating reactivity, it is preferable that the content of the thermoplastic resin is small and the content of the block copolymer containing metal fine particles and hydrophilic segments is large. From these two viewpoints, the content of the thermoplastic resin in the molded body is preferably 70 to 99.9% by weight, and more preferably 85 to 99.5% by weight.

  Examples of the mineral contained in the molded body include silicates such as calcium silicate, aluminum silicate, magnesium silicate, and silicon dioxide, silicic acid, calcium oxide, calcium carbonate, magnesium oxide, magnesium hydroxide, barium sulfate, And a compound (mineral) containing the same. In particular, silicates such as calcium silicate and magnesium hydroxide are preferable from the viewpoints of surface properties (appearance), mechanical strength, dimensional stability, and cost. Similarly, calcium oxide and silicon dioxide are also preferable as minerals used in this embodiment.

  Although the shape of the mineral contained in a molded object is not specifically limited, It is preferable that it is granular or substantially spherical. The granular or substantially spherical mineral is not conspicuous in the molded body, for example, and can improve the design of the molded body, as compared with a needle-like fiber.

  In this embodiment, by containing a mineral in a molded object, the curvature of a molded object can be suppressed and rigidity and dimensional stability can be improved. The content of the mineral in the molded body is preferably 10 to 65% by volume from the viewpoint of the surface property (appearance), mechanical strength, dimensional stability, moldability (ease of molding) of the molded product, and 30 to 50 volume% is more preferable.

  Moreover, the mineral which a molded object contains may contain at least one of lead (Pb) and sulfur (S). The mineral contained in the molded body is preferably a natural mineral from the viewpoint of cost reduction, and the natural mineral often contains lead (Pb) and / or sulfur (S). Lead and sulfur contained in the mineral may be lead alone or sulfur alone, or may be a lead compound or sulfur compound. Examples of the lead compound include lead sulfide, lead sulfate, and lead carbonate, and examples of the sulfur compound include iron sulfide, copper sulfide, zinc sulfide, and nickel sulfide. The content of lead in the molded body may be 0.1 to 1 ppm by weight, or 1 to 5 ppm by weight. 0.1 weight ppm-0.5 weight ppm may be sufficient as content of sulfur in a molded object, and 0.6 weight ppm-1 weight ppm may be sufficient.

  In the present embodiment, a thermoplastic resin containing a commercially available mineral may be used as the above-described thermoplastic resin and mineral. In general, a thermoplastic resin containing a mineral is called a “mineral reinforced resin”. Examples of commercially available mineral reinforced resins include Toyobo's mineral reinforced resin T777-02 and Ube Industries' mineral reinforced resins 1013R and 1013R1.

  The block copolymer containing a hydrophilic segment contained in the molded product (hereinafter referred to as “block copolymer” as appropriate) has a hydrophilic segment, and further has another segment (hereinafter referred to as a hydrophilic segment). And appropriately described as “other segment”). An anionic segment, a cationic segment, and a nonionic segment can be used for the hydrophilic segment. Examples of the anionic segment include polystyrene sulfonic acid series, the cationic segment includes quaternary ammonium base-containing acrylate polymer series, and the nonionic segment includes polyether ester amide series, polyethylene oxide-epichlorohydrin series, and polyether ester series. It is done. The hydrophilic segment is preferably a nonionic segment having a polyether structure because it is easy to ensure the heat resistance of the molded body. Examples of the polyether structure include polyoxyethylene group, polyoxypropylene group, polyoxytrimethylene group, polyoxytetramethylene group and other oxyalkylene groups, polyether diol, polyether diamine, and modified products thereof, and Polyether-containing hydrophilic polymers are included, and polyethylene oxide is particularly preferable.

  The other segment of the block copolymer is optional as long as it is more hydrophobic than the hydrophilic segment. For example, nylon, polyolefin and the like can be used. In addition, when a material compatible with the thermoplastic resin used for the molded body is used for the other segment, phase separation between the thermoplastic resin and the block copolymer is performed during molding of the molded body and inside the molded body after molding. Can be suppressed. On the other hand, if a material incompatible with the thermoplastic resin used for the molded product is used for the other segments, the block copolymer has a strong effect of moving to bleed out to the surface of the molded product, and segregates near the surface of the molded product. It becomes easy to do. Thereby, the permeability of the plating solution into the molded body can be increased. As a material compatible with the thermoplastic resin used for the molded body, a resin having the same structure as that of the thermoplastic resin or a similar structure is preferable. For example, when a polyamide resin such as nylon is used for the thermoplastic resin used in the molded body, the other segment is preferably nylon containing a polyamide component. Moreover, when using polyolefin resins, such as a polypropylene, for the thermoplastic resin used for a molded object, it is preferable that another segment contains a polyolefin component. On the other hand, as a material incompatible with the thermoplastic resin used for the molded body, a resin having a structure different from that of the thermoplastic resin or a different property is preferable. For example, if the thermoplastic resin used for the molded body is a polyolefin such as hydrophobic polypropylene, nylon or the like having relatively high hydrophilicity can be used for the other segments.

  Commercially available products may be used as the block copolymer, and for example, Pelestat (registered trademark), Peletron (registered trademark) manufactured by Sanyo Chemical Industries, Ltd. may be used. For example, Pelestat NC6321, 1251 manufactured by Sanyo Chemical Industries is a block copolymer obtained by copolymerizing a polyether of a hydrophilic segment and nylon of another segment with an ester bond.

  The content of the block copolymer in the molded body is preferably 0.1 to 30% by weight, and more preferably 0.5 to 15% by weight. When the weight is 0.1% by weight or more, the penetration of the plating solution into the shaped body can be increased when the shaped body is plated. When the weight is 30% by weight or less, the shaped body has sufficient mechanical strength. Furthermore, the thermal shock resistance can be maintained even after the plating film is formed.

  As the metal fine particles contained in the molded body, metal fine particles such as Pd, Ni, Pt, and Cu, precursors of metal oxides such as metal complexes and metal alkoxides can be used. The type of the metal complex is arbitrary, but more specifically, hexafluoroacetylacetonato palladium (II) metal complex, platinum dimethyl (cyclooctadiene), bis (cyclopentadienyl) nickel, bis (acetylacetonate) Palladium or the like is preferable because of its high solubility in pressurized carbon dioxide. These metal fine particles function as a plating catalyst, and the molded body can be subjected to electroless plating.

  The content of the metal fine particles in the molded body is preferably 0.1 ppm by weight or more, and more preferably 1 ppm by weight or more from the viewpoint of electroless plating reactivity. Further, the upper limit depends on the type of metal fine particles because it is determined by, for example, the saturation solubility of the metal fine particles in pressurized carbon dioxide in the method for producing a molded body described later.

  The molded body of this embodiment preferably has a surface roughness (Ra) of 1 μm or less. By reducing the surface roughness, the surface roughness of the plating film formed on the surface of the molded body can also be kept small, and the design of the plating film can be improved. For example, by using a granular or substantially spherical mineral as the mineral contained in the molded body, the surface roughness (Ra) of the molded body can be reduced to 1 μm or less.

[Method for producing molded article]
The molded body prepared in this embodiment is, for example, a first resin pellet containing a block copolymer and metal fine particles, and a second resin pellet containing the thermoplastic resin together with the first resin pellet. May be molded by plasticizing and melting.

  Thus, in the method for producing a molded body using the first and second resin pellets, the first resin pellet is a master batch, and the second resin pellet is a base resin into which the master batch is blended. It corresponds to. A masterbatch is a resin pellet containing functional materials such as dyes, pigments, and other additives at a high concentration, and is mixed with a base resin not containing a functional material and molded together with the base resin. When the master batch is used, the handling of the material is easy and the weighing accuracy is improved as compared with the case where the functional material is directly added to the base resin and molded. In the present embodiment, resin pellets (first resin pellets) containing a block copolymer and metal fine particles are used as a master batch containing a block copolymer and metal fine particles.

  The first resin pellet is obtained by plasticizing and melting a block copolymer, mixing pressurized carbon dioxide in which metal fine particles are dissolved into the plasticized and melted block copolymer, and a block in which metal fine particles are mixed. You may manufacture by a manufacturing method including pulverizing the block copolymer which mixed the extrusion molded metal microparticles | fine-particles and the extruded metal particle was mixed, and obtaining said 1st resin pellet. For example, a block copolymer is plasticized and melted in a plasticizing cylinder of an extruder, pressurized carbon dioxide in which metal fine particles are dissolved is supplied to the plasticizing cylinder, and the block copolymer is added to the plasticizing cylinder. Contact with pressurized carbon dioxide.

  The pressurized carbon dioxide is a solvent for the metal fine particles and also acts as a plasticizer for the block copolymer, and promotes uniform dispersion of the metal fine particles in the block copolymer. Therefore, when a molded body having a plating film is manufactured using the first resin pellets manufactured using pressurized carbon dioxide, a uniform and high-quality plating film can be obtained. Although it is possible to produce the first resin pellet by mixing only the block copolymer and metal fine particles without using pressurized carbon dioxide, it is preferable to use pressurized carbon dioxide for the above reasons. .

  In the first method for producing resin pellets, pressurized carbon dioxide in a liquid state, a gas state, or a supercritical state can be used as the pressurized carbon dioxide. These pressurized carbon dioxides are harmless to the human body, have excellent diffusibility into the molten resin, can be easily removed from the molten resin, and further function as a plasticizer for the molten resin. The pressure and temperature of the pressurized carbon dioxide introduced into the plasticizing cylinder are arbitrary, but liquid carbon dioxide or supercritical carbon dioxide is preferably used because of its high density and stability. The temperature of the pressurized carbon dioxide is preferably in the range of 5 ° C to 50 ° C. The lower the temperature of the pressurized carbon dioxide, the higher the density and the higher the solvent effect, which is preferable, but 5 ° C. or higher is preferable from the viewpoint of easy cooling control. Moreover, since there exists a possibility that a density may become low and liquid feeding may become unstable when the temperature of pressurized carbon dioxide becomes high, 50 degreeC or less is preferable from a viewpoint of liquid feeding stably. The pressure of the pressurized carbon dioxide is desirably in the range of 4 to 25 MPa. From the viewpoint of obtaining an appropriate solvent effect because the solvent effect is difficult to be expressed when the pressure is low, 4 MPa or more is preferable, and from the viewpoint of suppressing the cost because the high pressure equipment is costly when the pressure is high. 25 MPa or less is preferable. In addition, the pressurized carbon dioxide in which the metal fine particles are dissolved or dispersed instantaneously becomes high temperature in the plasticizing cylinder and the pressure fluctuates. Therefore, the above-mentioned pressurized carbon dioxide state, temperature and pressure are values of the pressurized carbon dioxide state, pressure and temperature in a stable state before being introduced into the plasticizing cylinder.

  Further, the pressurized carbon dioxide may contain a solvent that dissolves the metal fine particles. For example, when a metal complex is used as the metal fine particles, a fluorine-based organic solvent such as perfluoropentylamine may be used to increase the concentration of the metal complex in the pressurized carbon dioxide.

  The concentration of the metal fine particles in the pressurized carbon dioxide can be appropriately selected in consideration of the type of the metal fine particles, and is not particularly limited. Considering the permeability to the molten resin and the aggregation of the metal fine particles in the pressurized carbon dioxide, it is preferably not more than the saturation solubility. In particular, the density of carbon dioxide in the pressurized carbon dioxide is preferably about 1 to 50% of the saturation solubility because the density of carbon dioxide rapidly decreases in the plasticizing cylinder of the molding machine that reaches a high temperature.

  A method for preparing the pressurized carbon dioxide is not particularly limited, and a conventionally known method can be used. For example, you may use the pressurized fluid supply apparatus 100 provided with the syringe pump which attracts | sucks and sends pressurized carbon dioxide like the syringe shown in FIG. In the present embodiment, the pressurized fluid supply apparatus 100 manufactures pressurized carbon dioxide (hereinafter referred to as “mixed pressurized fluid” if necessary) in which metal fine particles are mixed at a predetermined ratio, and this mixed pressurization. Supply fluid to the plasticizing cylinder.

  The method of supplying the mixed pressurized fluid to the plasticizing cylinder is arbitrary. For example, the mixed pressurized fluid may be intermittently introduced into the plasticizing cylinder or may be continuously introduced. The introduction of the mixed pressurized fluid may be controlled by using, for example, a syringe pump capable of stable liquid feeding.

  After the mixed pressurized fluid is mixed with the block copolymer, the block copolymer containing metal fine particles is extruded and pulverized to obtain a first resin pellet.

  Next, together with the obtained first resin pellets, the second resin pellets that do not contain the metal fine particles but contain the thermoplastic resin are plasticized and melted to obtain a general-purpose injection molding machine, extrusion molding machine, etc. Using this molding machine, the molded body can be molded by a general-purpose molding method. Therefore, the manufacturing method of the present embodiment is a block co-polymer containing a thermoplastic resin, a mineral, metal fine particles as a plating catalyst, and a hydrophilic segment without making capital investment such as purchasing a new molding machine. A molded body containing the coalescence can be produced.

  In the method for producing a molded body described above, the first resin pellet (masterbatch) is formed only from the block copolymer and the metal fine particles, but the first resin pellet further includes the above-described thermoplastic resin or the like. Other materials may be included. When other materials are contained, it is preferable that the concentration of the block copolymer and the metal fine particles in the first resin pellet (master batch) is higher. For example, the content of the block polymer in the first resin pellet is preferably 20 to 100% by weight, and more preferably 50 to 100% by weight. Further, the content of the metal fine particles in the first resin pellet is preferably 5 ppm by weight or more, and more preferably 50 ppm by weight or more. The mixing ratio of the first resin pellet and the second resin pellet can be determined as appropriate based on the block copolymer concentration and the metal fine particle concentration in the target molded article. For example, the weight ratio ( (First resin pellet): (second resin pellet) = 0.1: 99.9 to 30:70.

  As mentioned above, although the manufacturing method of the molded object prepared by this embodiment was demonstrated, the manufacturing method of a molded object is not limited to this. For example, in addition to the block copolymer and the metal fine particles, the first resin pellet contains the above-described thermoplastic resin and mineral, and the molded body is formed only from the first resin pellet without using the second resin pellet. It may be manufactured. Moreover, although extrusion molding was performed for manufacture of the 1st resin pellet, you may manufacture by injection molding. Furthermore, the first resin pellet may be produced by a method in which pressurized carbon dioxide in which metal fine particles are dissolved is brought into contact with a pellet-shaped block copolymer (raw material pellet) in a high-pressure vessel. In this case, the metal fine particles penetrate into the raw material pellets together with the pressurized carbon dioxide, and the first resin pellets containing the metal fine particles can be manufactured.

[Plating pretreatment]
Next, a strong acid is brought into contact with the prepared block copolymer and the compact containing metal fine particles for 1 to 30 seconds (FIG. 1, step S2). In the present embodiment, the step of bringing a strong acid into contact with the molded product corresponds to a pretreatment for plating for forming a plating film on the molded product.

The “acid (strong acid)” used in the present embodiment is a compound that releases protons (H ⁺ ) in an aqueous solution, dissolves (etches) the surface of the molded body, and further contains block co-polymer contained in the molded body. A compound that softens or dissolves a coalescence. “The block copolymer softens” means that when the acid comes into contact with the block copolymer, the block copolymer does not dissolve in the acid but swells, and the hardness of the block copolymer is higher than that before the contact with the acid. It means lowering. Moreover, when a block copolymer melt | dissolves in an acid, it is guessed that the hydrophilic segment of a block copolymer mainly melt | dissolves in an acid. Whether the block copolymer is dissolved or simply swollen depends on the strength of the acid, the concentration, the temperature, the contact time between the molded product and the acid, and the like. Moreover, it is speculated that only one of the block copolymer may be dissolved or swelled, or both may occur simultaneously.

The strong acid used in the present embodiment is an acid having an acid dissociation constant Ka of 1.0 × 10 ⁻³ or more. From the viewpoint of improving the plating reactivity on the surface of the molded body, strong acids that can be used in this embodiment include hydrochloric acid, nitric acid, sulfuric acid, perchloric acid, hydrobromic acid, hydroiodic acid, chromic acid, and chloric acid. , Bromic acid, iodic acid, perbromic acid, metaperiodic acid, permanganic acid, thiocyanic acid, tetrafluoroboric acid and hexafluorophosphoric acid are preferable, and hydrochloric acid and nitric acid are more preferable. In the present embodiment, one type of strong acid may be used alone, or two or more types of strong acid may be mixed and used in an arbitrary ratio.

  The time during which the strong acid is brought into contact with the molded body (pretreatment time for plating) is 1 to 30 seconds. If it is less than 1 second, it will be difficult to etch the surface of the molded body or soften or dissolve the block copolymer. If it exceeds 30 seconds, a plating film non-deposited portion will be generated due to the dissolution of minerals described later. This is because there is a fear. In addition, for example, when the step of bringing a strong acid into contact with the molded body is automatically performed using an apparatus or the like, it is difficult to control the apparatus if the time for which the molded body is in contact with the strong acid is too short. The contact time is preferably 5 to 10 seconds.

  Further, the concentration of the strong acid brought into contact with the molded body is preferably 1.0 to 3.5N, and more preferably 1.0 to 3.0N. If it is less than 1.0 N, there is a risk that the surface of the molded body will be etched and the softening or dissolution of the block copolymer will be insufficient. If it exceeds 3.5 N, the plating film will not adhere due to the dissolution of minerals described later. This is because the portion is likely to be generated.

  Further, the temperature of the strong acid brought into contact with the molded body is preferably 10 ° C to 30 ° C. If the temperature is lower than 10 ° C, the surface of the molded body may be etched or the block copolymer may be insufficiently softened or dissolved. This is because it is likely to occur.

  In the present embodiment, it is preferable that the strong acid used for the plating pretreatment does not contain hexavalent chromic acid. This is because hexavalent chromic acid can etch the surface of the molded body and swell or dissolve the block copolymer contained in the molded body, but has high toxicity and environmental load.

  The method of bringing the strong acid into contact with the molded body is arbitrary, and various methods can be used depending on the purpose. For example, you may immerse the whole molded object in an acid. Further, when only a part of the molded body is subjected to plating, only the part where the plating process is scheduled may be brought into contact with the acid.

  When the plating pretreatment using the strong acid of the present embodiment is performed, the plating reactivity of the molded body is improved and the plating reaction time can be shortened. Moreover, since plating reactivity improves and it becomes easy to form a plating film, the plating reaction nonuniformity of the complex-shaped molded object can be suppressed. Furthermore, when the plating pretreatment using the strong acid of the present embodiment is performed, a plating film having sufficient adhesion strength can be formed on the molded body.

  The reason why the plating pretreatment using the strong acid of the present embodiment has the above-described effect is presumed as follows. However, the mechanism described below is merely an estimation, and the present invention is not limited thereby. In the pretreatment for plating, the strong acid etches the surface of the molded body, and further softens the block copolymer contained in the molded body to swell the thermoplastic resin. It becomes easy to penetrate from the surface to the inside. As a result, the electroless plating solution comes into contact with many metal fine particles, which are plating catalysts, and the plating reactivity is improved. Moreover, since the plating film grows from the inside of the molded body when the plating solution permeates into the molded body, a plated film having sufficient adhesion strength is formed. Further, in the pretreatment for plating, a strong acid etches the surface of the molded body and further dissolves the block copolymer, so that more metal fine particles can be exposed on the surface of the molded body. By exposing more metal fine particles to the surface of the molded body, it becomes easier to form a plating film on the surface of the molded body.

  The strong acid treatment of the present embodiment is particularly effective when an electroless plating film is formed on a complex shaped product. In a complex-shaped molded body, uneven distribution of metal fine particles on the surface of the molded body and unevenness in the degree of crystallinity of the resin are likely to occur, and uneven plating due to this is likely to occur. However, even in the case of a complex shaped product, the plating pretreatment using the strong acid of this embodiment improves the plating reactivity on the surface of the molded product, so that uneven plating can be suppressed and a uniform plating film can be formed. Can be formed.

  Note that the pretreatment for plating using a strong acid in the present embodiment is different from the conventional plating pretreatment for roughening the surface of the molded body. As a conventional plating pretreatment, there is known a method in which an ABS resin, an elastomer, a mineral, or the like is contained in a resin, and these are removed from the surface of the molded body with an etching solution having a high environmental load such as hexavalent chromic acid. Therefore, in the conventional plating pretreatment, relatively large unevenness is formed on the surface of the molded body. In contrast, the pretreatment of the strong acid plating according to the present embodiment slightly etches the surface of the molded body and further softens the block copolymer in the vicinity of the surface of the molded body, or the hydrophilicity of the block copolymer. Dissolve the sex segment. Even when the block copolymer is dissolved, the metal fine particles are only exposed to the surface of the molded body, and the surface of the molded body is not roughened.

  Furthermore, in this embodiment, generation | occurrence | production of a plating film non-adhered part can be suppressed by controlling the time (plating pretreatment time) which has contacted the strong acid with the molded object to 1 to 30 seconds. Here, the “plating film non-adhered portion” generated by performing a pre-plating treatment using a strong acid on a mineral-containing molded body is a portion where the plating reactivity is clearly different from other parts on the molded body. Yes, it is different from uneven plating and pinholes that are likely to occur in a complex shaped product. The plating film non-adhered portion is caused by the mineral, and the general size of the mineral mixed with the thermoplastic resin is several tens to several hundreds μm or less even if it is large. Therefore, it becomes a substantially circular shape centering on the mineral that causes the plating film non-attached portion, and the size is smaller than 1 mm. On the other hand, plating unevenness is caused by uneven distribution of metal fine particles on the surface of the molded body and unevenness of resin crystallinity on the surface of the molded body, and most of the size is 1 mm or more, and the shape is not circular. Many. Pinholes are also generated due to impurities adhering to the surface of the molded body, molding defects, etc., and most of them are not circular. Therefore, the plating film non-attached portion can be visually distinguished from plating unevenness and pinholes.

  In the present embodiment, the mechanism that can suppress the occurrence of the plating film non-adhered portion is assumed as follows. However, the mechanism described below is merely an estimation, and the present invention is not limited thereby. When the molded body contains a mineral, when plating pretreatment is performed using an acid, particularly a strong acid, a large number of plating film unattached portions where a plated film is not formed are generated on the surface of the molded body. The present inventors speculate that the cause is a lead (Pb) component or sulfur (S) component contained in the mineral. When a strong acid is used for the plating pretreatment, the strong acid dissolves the mineral, and the lead (Pb) component or the sulfur (S) component is eluted from the mineral. These are considered to inhibit the plating growth of electroless plating or reduce the plating catalytic activity of the metal fine particles to generate a plating film non-attached portion. In this embodiment, by controlling the pretreatment time for plating with a strong acid to be as short as 1 to 30 seconds, elution of lead (Pb) component or sulfur (S) component from the mineral is suppressed, and the plating film is not deposited. It is presumed that the generation of parts can be suppressed.

  Further, according to the present inventors, instead of performing a pretreatment for plating in a short time (1 to 30 seconds) using a strong acid, a pretreatment for plating is performed for a long time (more than 30 seconds) using a weak acid. It was also found that the generation of the plating film non-adhered portion can be suppressed. However, since the degree of dissociation of a weak acid changes depending on the temperature or the like, it is difficult to control and store the acid strength (pH), and a weak acid such as acetic acid has a problem of odor during work. On the other hand, the strong acid used in this embodiment is easy to control and store the acid strength (pH), and does not cause odor problems. Furthermore, there is an advantage that the plating pretreatment time is shorter than that of the weak acid.

  In the pre-plating treatment of this embodiment, only a strong acid may be brought into contact with the molded body, but an alcohol treatment liquid may be further contacted with the molded body. The alcohol treatment liquid can also swell the block copolymer contained in the molded product, and can further improve the plating reactivity of electroless plating. The plating pretreatment using the alcohol treatment liquid is performed after the plating pretreatment using a strong acid. When plating pretreatment using an alcohol treatment solution is performed before plating pretreatment using a strong acid, the electroless plating does not grow from the inside of the resin and immediately covers the surface of the molded body, resulting in extremely low adhesion strength. There is a possibility that a plating film is formed. The reason for this is not clear, but is presumed as follows. In general, the alcohol treatment liquid has a lower surface tension than the strong acid treatment liquid and is more easily penetrated into the molded body. Therefore, when the plating pretreatment using the alcohol treatment liquid is performed first, the alcohol treatment liquid remains in the molded body even after washing with pure water after the treatment, and the strong acid treatment treatment liquid (strong acid) performed thereafter. Does not penetrate into the molded body. As a result, etching or dissolution of the block copolymer occurs only on the outermost surface of the molded body, and activation of only the outermost surface of the molded body proceeds, and plating is performed on the outermost surface before plating growth from the inside of the molded body is performed. It is assumed that a film is formed.

  The alcohol treatment liquid contains an alcohol having a property of softening the block copolymer contained in the molded body. Examples of the alcohol contained in the alcohol treatment liquid include ethanol, 1-propanol, 2-propanol, 1,2-butanediol, 1,3-butanediol, 2-methoxyethanol, 2-ethoxyethanol, and 1-methoxy- 2-propanol, 1-ethoxy-2-propanol, 2-methyl-2,4-pentanediol, 2- (2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethanol, 2- (2-methoxyethoxy) ) Ethanol, ethylene glycol, diethylene glycol, tetraethylene glycol, polyethylene glycol, and polypropylene glycol.

  Furthermore, it is preferable that the alcohol contained in the alcohol treatment liquid has higher permeability to the molded body. Therefore, the surface tension at 20 ° C. of the alcohol used in the present embodiment is preferably lower than 73 dyn / cm, which is the surface tension of water at 20 ° C., and more preferably 50 dyn / cm or less. In consideration of safety in the plating process, the alcohol contained in the alcohol treatment liquid preferably has a flash point of 40 ° C. or higher. Examples of the alcohol satisfying both the low surface tension and the high flash point include 1,3-butanediol (surface tension: 37.8 dyn / cm, flash point: 121 ° C.), 2-methoxyethanol (surface Tension: 31.8 dyn / cm, flash point: 43 ° C., 2- (2-methoxypropoxy) propanol (surface tension: 28.8 dyn / cm, flash point: 74 ° C.), and the like. Among these, 1,3-butanediol having excellent permeability is more preferable. The alcohol contained in the alcohol treatment liquid may be one type of alcohol, or two or more types may be mixed and used at an arbitrary ratio.

  The alcohol treatment liquid used in the present embodiment may contain, in addition to alcohol, other solvents that are compatible with the alcohol to be used, such as water. However, if the content of the other solvent is too large, the above-described block copolymer is insufficiently softened in the plating pretreatment. For this reason, 30 volume% or more is preferable and, as for content of alcohol in an alcohol processing liquid, 50 volume% or more is more preferable. In particular, an alcohol treatment liquid consisting essentially of alcohol is preferred except for inevitable impurities mixed in in the case of industrial products. The alcohol treatment liquid may contain an additive in order to improve the permeability to the molded body. Examples of such additives include surfactants.

  The method of bringing the alcohol treatment liquid into contact with the molded body is arbitrary, and various methods can be used depending on the purpose. For example, the entire molded body may be immersed in an alcohol treatment liquid. In addition, when only a part of the molded body is plated, only the part where the plating process is scheduled may be brought into contact with the alcohol treatment liquid.

  The time for which the alcohol treatment liquid is brought into contact with the molded body can be arbitrarily set based on the type of thermoplastic resin and the type of alcohol contained in the molded body. When the time for which the alcohol treatment liquid is in contact with the molded body is too short, the alcohol does not sufficiently penetrate into the molded body, so that the block copolymer is not sufficiently softened by the alcohol treatment liquid. On the other hand, if the time for which the alcohol treatment liquid is in contact with the molded body is too long, the production efficiency is lowered, and the resin structure of the molded body may be weakened by alcohol. From such a viewpoint, the time during which the alcohol treatment liquid is in contact with the molded body is preferably, for example, 1 minute to 30 minutes.

  The pretreatment for plating with the alcohol treatment liquid may be performed at room temperature, or may be performed at a temperature higher than room temperature in order to promote softening of the block copolymer and impregnation of the alcohol treatment liquid into the molded body. . In particular, the plating pretreatment is preferably performed at a temperature equal to or higher than the glass transition temperature of the thermoplastic resin contained in the molded body. This is because when the temperature is equal to or higher than the glass transition temperature, the molded body is plastically deformed, and the alcohol treatment liquid easily penetrates into the molded body.

[Electroless plating]
Next, an electroless plating solution is brought into contact with the molded body in contact with a strong acid to form a plated film (FIG. 1, step S3), and a molded body having a plated film is obtained. As the electroless plating solution, any general-purpose electroless plating solution can be used depending on the purpose, but an electroless nickel phosphorous plating solution is preferable from the viewpoint that the catalyst activity is high and the solution is stable. Since the molded body prepared in this embodiment contains metal fine particles that function as a plating catalyst, it is not necessary to perform a plating catalyst application process when performing electroless plating.

  A plurality of different types of electroless plating films may be formed on the molded body that has undergone the plating pretreatment, and further, an electrolytic plating film may be formed on the electroless plating film by electrolytic plating. Good. Moreover, the molded body on which the electroless plating film is formed may be annealed after the electroless plating, or may be left to stand at room temperature to be naturally dried. Moreover, you may perform the following processes, such as forming an electrolytic plating film | membrane continuously, without performing annealing treatment and natural drying.

  In the present embodiment, the hydrophilic segment of the block copolymer moves to bleed out to the surface of the molded body during or after the molded body manufacturing process. Therefore, the block copolymer is unevenly distributed near the surface of the molded body, and only the vicinity of the surface of the molded body is hydrophilized by the hydrophilic segment of the block copolymer.

  In this embodiment, when an electroless plating solution is brought into contact with the molded body, the plating solution penetrates from the surface of the molded body to contact with the metal fine particles, and the plating is performed while spreading the resin molded body from the inside of the resin molded body. The film grows. At this time, since the surface vicinity of the molded body of this embodiment is hydrophilized by the block copolymer, it is considered that the penetration of the plating solution and the growth of the plating film are promoted. The molded body of the present embodiment has a good throwing power of the plating film, and the plating film can be formed in a short time. By shortening the plating film formation time, defects in the plating film such as pinholes are less likely to occur.

  On the other hand, since the block copolymer is segregated near the surface of the molded body, only the vicinity of the surface of the molded body is hydrophilized by the block copolymer. The block copolymer partially improves the hydrophilicity of the molded body, but has little influence on the water absorption (macroscopic water absorption) of the entire molded body. Therefore, the brittle fracture of the molded body in the plating solution can be suppressed, and the mechanical properties of the molded body are not deteriorated. As a result, the molded body has sufficient thermal shock resistance even after the plating film is formed.

  Furthermore, in this embodiment, it is presumed that as the block copolymer moves to the vicinity of the surface of the molded body, the metal fine particles also move to the vicinity of the surface and are likely to be unevenly distributed near the surface. The reason for this phenomenon is not clear, but the metal fine particles are unevenly distributed near the surface, making it easier to form a plating film on the surface of the resin, suppressing a decrease in the adhesion of the plating film, plating reaction unevenness, pinholes, etc. The appearance defect is reduced.

  In the present specification, the “near the surface of the molded body” means an area inside the molded body and close to the surface. When the molded body is brought into contact with the plating solution, the plating solution is exposed from the surface. It means the area where plating penetrates and plating reaction occurs. The extent to which “near the surface of the molded body” means the region from the surface of the molded body varies depending on the type of resin used in the molded body. A region having a depth of 1 to 10 μm.

  In the present embodiment, by using a block copolymer, only the vicinity of the surface of the molded body can be made hydrophilic, and the above-described effects can be achieved. For example, in the case of a random copolymer composed of the same constituent components, a polymer composed only of hydrophilic segments, etc., it is difficult to hydrophilize only the vicinity of the surface of the molded body, and the same effect as the present invention cannot be obtained. . Further, the low molecular surfactant also has a property of segregating on the surface of the molded body, but cannot provide the same effect as the block copolymer of the present embodiment. The block copolymer is a polymer, unlike ordinary low-molecular surfactants. Since the block copolymer has a large molecular weight, it is considered that the block copolymer can move to the vicinity of the surface of the molded body with the mixed metal fine particles. Moreover, since it is a polymer, even if it is unevenly distributed at a high concentration on the surface of the molded body, the heat resistance and mechanical strength of the molded body are not reduced. Further, as described above, since it has a sufficient viscosity in the plasticized and melted state, even a block copolymer alone can be extruded and pelletized.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not restrict | limited by the following Example and comparative example.

[Example 1]
In this embodiment, a resin pellet manufacturing apparatus 1000 shown in FIG. 2 is used to manufacture a first resin pellet containing a block copolymer containing a hydrophilic segment and metal fine particles, and then a general-purpose injection. Using a molding machine, a molded body was molded from the first resin pellet and the second resin pellet containing a thermoplastic resin. And the plating film was formed on the manufactured molded object.

  As the block copolymer contained in the first resin pellet, a polyether ester amide block copolymer (Periostat NC6321 manufactured by Sanyo Chemical Industries, Ltd.) in which polyethylene oxide and a polyamide component are ester-bonded, as metal fine particles, Hexafluoroacetylacetonato palladium (II) metal complex which is an organometallic complex was used. The hydrophilic segment in the polyetheresteramide block copolymer is polyethylene oxide, which is a polyether. Further, as the second resin pellet, mineral-reinforced nylon 6 (product name: T777-02, manufactured by Toyobo Co., Ltd.) in which 40% by volume of a mineral containing calcium oxide and silicon dioxide was mixed was used. Further, 3.0N hydrochloric acid was used as the acid used for the plating pretreatment.

<Resin pellet manufacturing equipment>
First, the apparatus used for manufacture of the 1st resin pellet in a present Example is demonstrated. As shown in FIG. 2, a resin pellet manufacturing apparatus 1000 extrudes an extrusion molding apparatus 200 that extrudes a block copolymer mixed with metal fine particles, and pressurized carbon dioxide (mixed pressurized fluid) containing metal fine particles. A pressurized fluid supply device 100 supplied to the device 200, a resin cooling device 300 that cools the block copolymer extruded by the extrusion molding device 200, and a control device (not shown) are provided. The control device controls the operation of the pressurized fluid supply device 100, the extrusion molding device 200, and the resin cooling device 300.

  The pressurized fluid supply device 100 prepares a mixed pressurized fluid by mixing pressurized carbon dioxide and a solution C in which metal fine particles are dissolved in a solvent, and supplies the prepared mixed pressurized fluid to the extrusion molding device 200. To do. The pressurized fluid supply apparatus 100 includes a siphon-type carbon dioxide cylinder 101, a carbon dioxide syringe pump 102 that supplies liquid carbon dioxide after sucking liquid carbon dioxide from the carbon dioxide cylinder 101, and contains metal fine particles. It is comprised from the solution tank 111 which accommodates the liquid C, and the solution syringe pump 112 which pressurizes and supplies the metal fine particle containing liquid C in the solution tank 111. FIG. Each syringe pump 102, 112 is capable of pressure control and flow rate control. The prepared mixed pressurized fluid is supplied to the extrusion molding apparatus 200 via the back pressure valve 120.

  The extrusion molding apparatus 200 includes a first cylinder (plasticizing cylinder) 210 having a screw 20 rotatably disposed therein, a second cylinder 220 having a screw 25 rotatably disposed therein, and a screw. The servo motors 28 and 29 are connected to the motors 20 and 25 to rotate the screws 20 and 25, respectively, and the connecting part 230 connects the first cylinder 210 and the second cylinder 220. In the present embodiment, in the first and second cylinders 210 and 220, the plasticized and melted molten resin flows from the right hand to the left hand in FIG. Therefore, in the first and second cylinders 210 and 220, the right hand in FIG. 2 is defined as “upstream” or “rear”, and the left hand is defined as “downstream” or “front”. The first cylinder (plasticizing cylinder) 210 is provided with a ring-shaped seal member 26 through which the screw 20 passes, and a ring-shaped member 24 through which the screw 20 passes, provided downstream of the seal member 26. Further, the second cylinder 220 has a nozzle 27 at its tip.

  On the upper side surface of the first cylinder 210, in order from the upstream side, a resin supply port 201 for supplying the block copolymer to the plasticizing cylinder 210, an introduction for introducing the mixed pressurized fluid into the first cylinder 210. A mouth 202 is formed. A resin supply hopper 211 and an introduction valve 212 are disposed in the resin supply port 201 and the introduction port 202, respectively. A band heater (not shown) is disposed on the outer wall surface of the first cylinder 210, whereby the plasticizing cylinder 210 is heated and the block copolymer is plasticized and melted. In addition, a vent 203 for exhausting carbon dioxide gasified from the inside of the second cylinder 220 is formed on the upper side surface of the second cylinder 220.

  In the extrusion molding apparatus 200, a block copolymer is supplied from the resin supply port 201 into the first cylinder 210, and the block copolymer is plasticized by a band heater to become a molten resin. Sent to. The molten resin sent to the vicinity of the inlet 202 is contact-kneaded with pressurized carbon dioxide (mixed pressurized fluid) containing the introduced metal fine particles under high pressure. The molten resin containing the mixed pressurized fluid is sent from the first cylinder 210 to the downstream connecting portion 230. The resin of the connecting portion 230 is extruded into the resin sequentially supplied from the first cylinder 210 and further sent to the second cylinder 220 downstream. In the second cylinder 220, the gasified carbon dioxide is separated from the molten resin by exhausting from the vent 203 by reducing the internal pressure of the molten resin kneaded in contact with the mixed pressurized fluid. After the carbon dioxide is exhausted, the molten resin is sent downstream as the screw 25 rotates and is pushed out of the second cylinder 220 from the nozzle 27.

  As described above, in the first cylinder 210, the block copolymer is plasticized and melted to form a molten resin in order from the upstream side, and mixed pressure introduced from the molten resin and the introduction port 202. A kneading zone 22 is formed in which the fluid is contact-kneaded under high pressure. And in the 2nd cylinder 220, the pressure_reduction | reduced_pressure zone 23 which exhausts the carbon dioxide isolate | separated from molten resin from the vent 203 is formed by reducing the resin internal pressure of the molten resin contact-kneaded with the mixed pressurized fluid. In the first cylinder 210, the ring-shaped seal member 26 described above is located at the boundary between the plasticizing zone 21 and the kneading zone 22, and the ring-shaped member 24 is located in the kneading zone 22. And the part located in the kneading | mixing zone 22 of the screw 20 has a shape where the diameter becomes large as it goes downstream.

  The resin cooling device 300 is a device that cools and solidifies the block copolymer extruded from the nozzle 27 of the second cylinder 220, and is optional as long as the block copolymer is sufficiently solidified by cooling water or the like. However, in this embodiment, an aluminum belt conveyor device 301 that does not use cooling water is used. By not using cooling water, excessive water absorption of the block copolymer can be prevented, and a difficult dehydration operation in the subsequent process becomes unnecessary. As shown in FIG. 2, the aluminum belt conveyor device 301 is a belt conveyor that rotates a ring-shaped aluminum belt, and the block copolymer extruded from the extrusion molding device 200 is cut onto the aluminum belt. And transport from upstream to downstream (from right hand to left hand) in FIG. By being placed on an aluminum belt having high heat dissipation performance, the extruded block copolymer is cooled and solidified while being transported.

<Production of first resin pellet>
Using the resin pellet manufacturing apparatus 1000 shown in FIG. 2 described above, resin pellets were manufactured by the method described below. First, liquid carbon dioxide was sucked from the liquid carbon dioxide cylinder 101, and liquid carbon dioxide was pressurized to a predetermined pressure by pressure control of the carbon dioxide syringe pump 102. The solution syringe pump 112 sucks the solution C in which metal fine particles are dissolved in the solvent from the solution tank 111, and pressurizes the solution C to a predetermined pressure by controlling the pressure of the solution syringe pump 112. In this example, a fluorine-based organic solvent of perfluoropentylamine was used as the solvent of the solution C.

  Next, the carbon dioxide syringe pump 102 and the solution syringe pump 112 were switched from pressure control to flow rate control, and were flowed so that the flow rate ratio between the carbon dioxide syringe pump 102 and the solution syringe pump 112 was 10: 1. . As a result, the pressurized carbon dioxide and the solution C were mixed in the pipe, and the system up to the introduction valve 212 for introducing the mixed pressurized fluid into the first cylinder 210 was pressurized. In this example, the system from the syringe pumps 102 and 112 to the introduction valve 212 was cooled to 10 ° C., and the pressure was 10 MPa. The set pressure of the back pressure valve 120 was also set to 10 MPa. In this example, the concentration of the metal fine particles in the mixed pressurized fluid was controlled to about 10 to 20% of the saturation solubility.

  On the other hand, in the extrusion molding apparatus 200, the block copolymer is supplied from the resin supply hopper 211, and the plasticizing zone 21 is heated by a band heater (not shown) provided on the outer wall surface of the plasticizing zone 21. 20 was rotated. As a result, the block copolymer was plasticized and melted and flowed to the downstream kneading zone 22.

  In the kneading zone 22, the mixed pressurized fluid was continuously supplied at a constant flow rate into the plasticizing cylinder 210 through the introduction port 202 by the introduction valve 212. Then, by rotating the screw 20, the mixed pressurized fluid was dispersed and kneaded in the molten resin (molten block copolymer). At this time, the ring-shaped sealing member 26 prevents carbon dioxide and metal fine particles introduced into the kneading zone 22 from leaking into the upstream plasticizing zone 21.

  Next, the rotation of the screw 20 caused the resin in the kneading zone 22 to flow to the downstream connecting portion 230. In the kneading zone 22, when the resin flows downstream, the shape of the screw 20 and the presence of the ring-shaped member 24 whose diameter increases as it goes downstream becomes the flow resistance of the molten resin, and the internal pressure of the resin in the kneading zone 22 is reduced. As a result, the pressure in the first cylinder 210 increases.

  The kneading zone 22 is provided with a pressure sensor (not shown) so that the cylinder pressure in the kneading zone 22 can be monitored. When the pressure in the cylinder of the kneading zone 22 decreases due to a change in the resin viscosity or the like, the rotation speed of the servo motor 28 is increased to increase the amount of molten resin supplied to the kneading zone 22, Increase pressure. On the contrary, when the pressure in the cylinder rises, the rotational speed of the servo motor 28 is lowered to reduce the resin supply amount, and the pressure in the cylinder is lowered. Thus, the 1st cylinder of a present Example has a mechanism which can keep cylinder internal pressure constant by adjusting screw rotation speed. When the fluctuation of the pressure in the cylinder of the kneading zone 22 is large, the introduction amount of the mixed pressurized fluid supplied from the syringe pumps 102 and 112 is not stable and varies, but in this embodiment, in the kneading zone 22 The introduction amount is stabilized by keeping the pressure in the cylinder constant. In this example, the rotation speed of the screw 20 was set so that the cylinder internal pressure in the kneading zone 22 was maintained at 8 MPa.

  The screw 20 was continuously rotated, and the molten resin (molten block copolymer) in the first cylinder 210 was continuously supplied to the downstream connecting portion 230. The molten resin in the connecting portion 230 flowed into the decompression zone 23 of the downstream second cylinder 220 while being pushed out by the molten resin supplied from the first cylinder. In the decompression zone 22, the pressure of the molten resin was reduced, and only carbon dioxide dissolved in the molten resin was separated and discharged from the vent 203 provided in the second cylinder 220.

  Next, the molten resin from which carbon dioxide was discharged (molten block copolymer) was extruded by the rotation of the screw 25 from the nozzle 27 provided at the tip of the second cylinder. The extrusion amount of the molten resin from the nozzle 27 was adjusted by a servo motor 29. The servo motor 29 can be controlled independently from the servo motor 28.

  The block copolymer extruded from the nozzle 27 was placed on the aluminum belt conveyor 301 of the cooling device 300 and conveyed from the upstream side to the downstream side in FIG. The extruded molten resin (molten block copolymer) was cooled and solidified during transportation. The solidified block copolymer was cut into an arbitrary size by a general-purpose cutting machine to obtain a first resin pellet containing palladium metal fine particles and a block copolymer. The concentration of the metal fine particles in the first resin pellet was 500 ppm by weight.

<Molding of molded body>
The obtained first resin pellets and second resin pellets are mixed at a weight ratio of 10:90, and general-purpose molding is performed using a general-purpose foam injection molding machine (manufactured by Nippon Steel Works, J180AD-2M). A 6 cm × 4 cm × 0.2 cm flat plate shaped product was formed by the method. In this example, the physical foaming agent was not used, and the resin filling rate of the molten resin into the mold was set to 100% with respect to the volume of the mold cavity, and a non-foamed molded body was molded.

<Plating pretreatment>
Next, the obtained molded body was immersed in hydrochloric acid (3.0 N) at 25 ° C. for 30 seconds. After being immersed in hydrochloric acid, the molded body was washed with pure water.

<Plating treatment>
The molded body subjected to the plating pretreatment was immersed in an electroless nickel phosphorus plating solution (Okuno Pharmaceutical Co., Ltd., Top Nicolon HMA-LF) at 70 to 90 ° C. for 15 minutes to form an electroless nickel phosphorus plating film. Next, the formed body on which the nickel phosphorus plating film was formed was immersed in a room temperature replacement copper plating solution (ANC Acti, manufactured by Okuno Pharmaceutical Co., Ltd.) for 1 minute to form a replacement copper plating film. Thereafter, since water was absorbed into the resin during electroless plating, the molded body on which the copper plating film was formed was placed in an electric furnace and annealed at 80 ° C. for 1 hour to promote dehydration.

  Next, an activator solution having a concentration of 100 g / L was prepared using an activator (Okuno Pharmaceutical Co., Ltd., Topsun). The formed article subjected to the annealing treatment was immersed in the prepared activator solution for 5 minutes at room temperature to activate the metal film on the formed article. By this treatment, the oxide film formed on the outermost surface of the molded body by annealing was removed.

An electrolytic copper plating film having a thickness of 20 μm was formed on the molded body subjected to the activation treatment by a general-purpose electrolytic plating method. As the electrolytic copper plating solution, a copper sulfate bath containing copper sulfate, sulfuric acid, hydrochloric acid and a brightener was used, the bath temperature was 30 ° C., and the current density was 3 A / dm ² . Furthermore, a 20 μm electrolytic nickel plating film was formed on the electrolytic copper plating film by a general-purpose method. As the electrolytic nickel plating solution, a Watt bath containing nickel sulfate, nickel chloride, boric acid and a brightener was used, the bath temperature was 55 ° C., and the current density was 3 A / dm ² .

  The molded body on which the electrolytic plating film was formed as described above was placed in an electric furnace and annealed at 80 ° C. for 1 hour to obtain a sample of this example (molded body having a plated film). In this embodiment, after forming the replacement copper plating film, the annealing treatment is performed to promote dehydration of the molded body that has absorbed water during the electroless plating. However, the annealing treatment may not be performed. Instead of the annealing treatment, the molded body on which the copper plating film is formed may be left at room temperature, or the next processing step may be performed continuously without leaving the molded body at room temperature. When the next step is performed after the replacement copper plating film is formed, the activation treatment may be omitted and electrolytic copper plating may be performed.

[Example 2]
In Example 2, a molded body (sample) having a plating film was formed by the same method as in Example 1 except that the pre-plating treatment was performed with the molded body immersed in hydrochloric acid for 5 seconds. Manufactured.

[Example 3]
In Example 3, as a pretreatment for plating, the molded body was immersed in hydrochloric acid (3.0 N) at 25 ° C. for 30 seconds, and after the immersion, the molded body was washed with pure water, and further, 1,3-butanediol at 80 ° C. It was immersed in an aqueous solution (75% by volume) for 15 minutes, and the molded body was washed with pure water after the immersion. A molded body (sample) having a plating film was manufactured by the same method using the same material as in Example 1 except for the pretreatment for plating.

[Example 4]
In Example 4, as a pretreatment for plating, the molded body was immersed in hydrochloric acid (3.0 N) at 25 ° C. for 5 seconds, and after the immersion, the molded body was washed with pure water, and further, 1,3-butanediol at 80 ° C. It was immersed in an aqueous solution (75% by volume) for 15 minutes, and the molded body was washed with pure water after the immersion. A molded body (sample) having a plating film was manufactured by the same method using the same material as in Example 1 except for the pretreatment for plating.

[Example 5]
In Example 5, a molded body (sample) having the same material as in Example 1 and having a plating film by the same method except that nitric acid (2.5N) was used instead of hydrochloric acid to perform pre-plating treatment. Manufactured.

[Example 6]
In Example 6, a molded body (sample) having a plating film was formed in the same manner as in Example 5 except that the pre-plating treatment was performed with the molded body immersed in nitric acid for 5 seconds. Manufactured.

[Example 7]
In Example 7, as a pretreatment for plating, the molded body was immersed in nitric acid (2.5 N) at 25 ° C. for 30 seconds, and after the immersion, the molded body was washed with pure water, and further, 1,3-butanediol at 80 ° C. It was immersed in an aqueous solution (75% by volume) for 15 minutes, and the molded body was washed with pure water after the immersion. A molded body (sample) having a plating film was manufactured by the same method using the same material as in Example 1 except for the pretreatment for plating.

[Example 8]
In Example 8, as a pretreatment for plating, the molded body was immersed in nitric acid (2.5 N) at 25 ° C. for 5 seconds, and after the immersion, the molded body was washed with pure water, and further, 1,3-butanediol at 80 ° C. It was immersed in an aqueous solution (75% by volume) for 15 minutes, and the molded body was washed with pure water after the immersion. A molded body (sample) having a plating film was manufactured by the same method using the same material as in Example 1 except for the pretreatment for plating.

[Comparative Example 1]
In Comparative Example 1, as a pretreatment for plating, the molded body was immersed in hydrochloric acid (3.0N) at 25 ° C. for 60 seconds. A molded body (sample) having a plating film was manufactured by the same method using the same material as in Example 1 except for the pretreatment for plating.

[Comparative Example 2]
In Comparative Example 2, as a pretreatment for plating, the molded body was immersed in hydrochloric acid (3.0 N) at 25 ° C. for 60 seconds, and after the immersion, the molded body was washed with pure water, and further, 1,3-butanediol at 80 ° C. It was immersed in an aqueous solution (75% by volume) for 15 minutes, and the molded body was washed with pure water after the immersion. A molded body (sample) having a plating film was manufactured by the same method using the same material as in Example 1 except for the pretreatment for plating.

[Comparative Example 3]
In Comparative Example 1, as a pretreatment for plating, the molded body was immersed in nitric acid (2.5N) at 25 ° C. for 60 seconds. A molded body (sample) having a plating film was manufactured by the same method using the same material as in Example 1 except for the pretreatment for plating.

[Comparative Example 4]
In Comparative Example 4, as a pretreatment for plating, the molded body was immersed in nitric acid (2.5 N) at 25 ° C. for 60 seconds, and after the immersion, the molded body was washed with pure water, and further, 1,3-butanediol at 80 ° C. It was immersed in an aqueous solution (75% by volume) for 15 minutes, and the molded body was washed with pure water after the immersion. A molded body (sample) having a plating film was manufactured by the same method using the same material as in Example 1 except for the pretreatment for plating.

[Comparative Example 5]
In Comparative Example 5, a molded body (sample) having a plating film was manufactured by the same method using the same material as in Example 1 except that the pretreatment for plating was not performed. However, in Comparative Example 5, since the electroless plating film (electroless nickel phosphorous film) was not formed on the entire surface of the molded body even after being immersed in the electroless plating solution for 15 minutes, the electroless plated film was formed on the entire surface of the molded body. Until then, the compact was kept immersed in the electroless plating solution for 19.6 minutes.

[Reference Example 1]
In Reference Example 1, nylon 6 (non-reinforced nylon 6) containing no mineral (CM1017 manufactured by Toray) was used as the second resin pellet. Except for the second resin pellet, the same material as in Comparative Example 1 was used, and a molded body (sample) having a plating film was produced by the same method.

<Evaluation>
The following evaluation items (1) to (3) were evaluated in the preparation process of the samples in Examples 1 to 8, Comparative Examples 1 to 5 and Reference Example 1 or the prepared samples.

(1) Evaluation of plating film non-adhered portion In the molded bodies produced in Examples 1 to 8, Comparative Examples 1 to 5 and Reference Example 1, the surface was visually observed at the stage where the electroless nickel phosphorus plating film was formed, The number of plating film non-adhered portions present on the entire surface of the sample was counted to determine the number of plating film non-adhered portions per unit area (cm ² ). In each Example etc., the same evaluation was performed about five molded objects. The results are shown in Table 1.

(2) Measurement of adhesion strength Using a tensile tester (manufactured by Shimadzu Corp., AGS-100N), in accordance with JIS H8630, under the conditions of an angle of 90 ° and a speed of 25 mm / min over a length of 40 mm on the sample surface, The force when peeling the plating film from the sample was measured. In each Example etc., the same test was done about five samples and the average value was calculated | required. The results are shown in Table 1.

(3) Composition analysis around the plating film non-adhered portion In the molded body produced in Comparative Example 1, the periphery of the plating film non-adhered portion generated at the stage of forming the electroless nickel phosphorus plating film was scanned with an electron microscope (SEM). Was observed. An SEM photograph is shown in FIG. The composition analysis of the plating film non-adhered portion 1 shown in FIG. 3A was performed with an electron probe microanalyzer (EPMA). As a result, lead (Pb): 15.7 wt% (1.27 mol%) and sulfur (S): 2.12 wt% (1.11 mol%) were detected from the plating film non-attached portion 1. .

  Next, in the molded body manufactured in Comparative Example 1, the cross section of the plating film non-attached portion 1 and the cross section of the portion where the plating film is formed (plating film forming portion) 2 shown in FIG. Was observed. FIG. 3B shows a SEM photograph of the cross section of the plating film non-attached portion 1, and FIG. 3C shows a SEM photograph of the cross section of the plating film forming portion 2. As shown in FIG. Minerals M1 and M2 were observed in the cross section of the plating film non-attached portion 1 and the cross section of the plating film forming portion 2, respectively. The minerals M1 and M2 shown in FIGS. 3B and 3C were subjected to composition analysis by energy dispersive X-ray spectroscopy (EDX). As a result, in addition to calcium oxide and silicon dioxide-derived calcium (Ca), silicon (Si), oxygen (O), lead (Pb): 53.7 Weight% (7.68 mol%), sulfur (S): 10.8 wt% (10.0 mol%) were detected. On the other hand, lead (Pb) and sulfur (S) were not detected from the mineral M2 present in the plating film forming part 2.

<Discussion>
(1) About plating film non-attachment part In Examples 1-8 in which the compact was immersed in strong acid (hydrochloric acid or nitric acid) for 30 seconds or 5 seconds as a pretreatment for plating, the plating film per unit area (cm ² ) The number of unattached portions was small and was in the range of 0 to 4 pieces / cm ² . In particular, in Examples 2, 4, 6 and 8 in which the molded body was immersed in strong acid (hydrochloric acid or nitric acid) for 5 seconds as a pretreatment for plating, the number of plating film non-adhered portions per unit area (cm ² ) was and 0-1 / cm ^2, was very small.

On the other hand, in Comparative Examples 1 to 4 in which the molded body was immersed in strong acid (hydrochloric acid or nitric acid) for 60 seconds as pre-plating treatment, the number of plating film unattached portions per unit area (cm ² ) was large, and 5 to 58 It was in the range of pieces / cm ² .

  From the above results, from the viewpoint of forming a uniform plating film having excellent appearance characteristics by reducing the number of plating film unattached portions, it is preferable that the pretreatment time for plating using a strong acid is short, and it is necessary to set it to 30 seconds or less. I found out.

In Reference Example 1 using a molded body containing no mineral, in the same manner as in Comparative Example 1, although the molded body was immersed in hydrochloric acid for 60 seconds, the plating film non-adhered portion per unit area (cm ² ) the number is, the 0-1 / cm ^2, it was very small. And Pb and S are detected from the mineral M1 which exists in the plating film non-attachment part 1 of the sample produced in Comparative Example 1, while Pb and S are detected from the mineral M2 which exists in the plating film formation part 2. Not detected.

  From the above results, the following can be inferred. The strong acid used for the plating pretreatment causes some adverse effects on the plating reaction by eluting Pd or S in the mineral by some reaction such as dissolving the mineral contained in the molded body. Thereby, the plating film non-adhered portion is formed in the portion containing S or Pd on the surface of the molded body. In Examples 1 to 8, it is considered that the elution of Pd or S in the neral can be suppressed and the occurrence of the plating film non-adhered portion can be suppressed by setting the plating pretreatment time using a strong acid to 30 seconds or less.

In Comparative Example 5 in which the plating pretreatment using a strong acid was not performed, the number of plating film non-adhered portions per unit area (cm ² ) was small as in Examples 1 to 8, but as will be described later. Furthermore, the adhesion strength of the plating film was below the target value.

(2) Adhesive strength The target value of the adhesive strength of the plating film is 10 N / cm or more. As shown in Table 1, in Examples 1 to 8 where a strong acid was used for the plating pretreatment, an adhesion strength higher than the target value could be obtained. Among them, Examples 3, 4, 7 and 8 which performed plating pretreatment using an alcohol treatment liquid in addition to plating pretreatment using a strong acid obtain particularly high adhesion strength of 16.7 N / cm or more. I was able to. On the other hand, in Comparative Example 5 where the plating pretreatment using a strong acid was not performed, the adhesion strength was less than the target value.

In Comparative Examples 1 to 4 using a strong acid for the plating pretreatment, an adhesion strength equal to or higher than the target value could be obtained, but as described above, the plating film unattached portion per unit area (cm ² ). There were many.

  In Examples 1 to 8 described above, the minerals contained in the molded body were calcium oxide and silicon dioxide, but other minerals such as calcium silicate, aluminum silicate, magnesium silicate, and dioxide. It is speculated that the same result can be obtained even if the molded body contains at least one selected from the group consisting of silicon, calcium oxide, calcium carbonate, magnesium oxide, magnesium hydroxide, barium sulfate and compounds containing these. The

  In Examples 3, 4, 7 and 8, 1,3-butanediol aqueous solution was used as the alcohol treatment liquid. However, other alcohol treatment liquids such as ethanol, 1-propanol, 2-propanol, 1, 2-butanediol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 2-methyl-2,4-pentanediol, 2- (2-butoxyethoxy) Alcohol treatment containing at least one selected from the group consisting of ethanol, 2- (2-ethoxyethoxy) ethanol, 2- (2-methoxyethoxy) ethanol, ethylene glycol, diethylene glycol, tetraethylene glycol, polyethylene glycol, and polypropylene glycol Even with liquid It is presumed to be obtained a like result.

  In Examples 1-8, although the 1st resin pellet was manufactured using extrusion molding, the pressurization carbon dioxide which metal fine particles dissolved was made to contact other manufacturing methods, for example, a pellet-like block copolymer. Therefore, it is estimated that the same result can be obtained even if the first resin pellet is manufactured.

  The method for producing a molded article having a plated film of the present invention can produce a molded article having a plated film having high adhesion strength as an initial characteristic and excellent in appearance characteristics. Therefore, the molded body having a plated film manufactured according to the present invention can be used for decorative purposes that require high durability. Moreover, since the electroless plating time can be shortened, the production efficiency of a molded body having a plating film is also improved.

21 Plasticization zone 22 Kneading zone 23 Decompression zone 20, 25 Screw 28, 29 Servo motor 24 Ring-shaped member 26 Seal member 27 Nozzle 100 Pressurized fluid supply device 200 Extrusion molding device 300 Resin cooling device 101 Carbon dioxide cylinder 102 For carbon dioxide Syringe pump 111 Solution tank 112 Syringe pump 120 for solution Back pressure valve 201 Resin supply port 202 Inlet port 203 Vent 210 First cylinder (plasticizing cylinder)
211 resin supply hopper 212 introduction valve 220 second cylinder 230 connecting part 301 belt conveyor device 1000 resin pellet manufacturing device

Claims (21)

A method for producing a molded body having a plating film,
Producing a first resin pellet containing a block copolymer containing a hydrophilic segment and metal fine particles;
Plasticizing and melting the first resin pellet and the second resin pellet containing mineral and polyamide to form a molded body;
Contacting the molded product with a strong acid for 1 to 30 seconds;
Contacting the electroless plating solution to said molded body is brought into contact with the strong acid, saw including forming a plating film,
Producing the first resin pellets,
Plasticizing and melting the block copolymer;
Mixing the plasticized and melted block copolymer with pressurized carbon dioxide in which the metal fine particles are dissolved;
Extruding a block copolymer in which the metal fine particles and pressurized carbon dioxide are mixed;
The manufacturing method of the molded object which has a plating film including grind | pulverizing the said extrusion-molded block copolymer and obtaining said 1st resin pellet .   The said mineral contains at least one of lead and sulfur, The manufacturing method of the molded object which has a plating film of Claim 1 characterized by the above-mentioned.   The strong acid is hydrochloric acid, nitric acid, sulfuric acid, perchloric acid, hydrobromic acid, hydroiodic acid, chromic acid, chloric acid, bromic acid, iodic acid, perbromic acid, metaperiodic acid, permanganic acid, thiocyanate The method for producing a molded body having a plating film according to claim 1 or 2, wherein the method is at least one selected from the group consisting of an acid, tetrafluoroboric acid and hexafluorophosphoric acid.   The method for producing a molded body having a plating film according to claim 3, wherein the strong acid is hydrochloric acid or nitric acid.   The method for producing a molded body having a plating film according to any one of claims 1 to 4, wherein a strong acid is brought into contact with the molded body for 5 to 30 seconds.   The method for producing a molded body having a plated film according to any one of claims 1 to 5, wherein the concentration of the strong acid is 1.0 to 3.5N.   The method for producing a molded body having a plated film according to claim 6, wherein the concentration of the strong acid is 1.0 to 3.0 N.   The method for producing a molded body having a plated film according to any one of claims 1 to 7, wherein the temperature of the strong acid is 10 to 30 ° C. The mineral is
At least one selected from the group consisting of calcium silicate, aluminum silicate, magnesium silicate, silicon dioxide, calcium oxide, calcium carbonate, magnesium oxide, magnesium hydroxide, barium sulfate and compounds containing these,
The method for producing a molded body having a plated film according to any one of claims 1 to 8, comprising at least one of lead and sulfur. The mineral is
At least one of calcium oxide and silicon dioxide;
The method for producing a molded body having a plated film according to claim 9, comprising at least one of lead and sulfur.   The said mineral is a natural mineral, The manufacturing method of the molded object which has a plating film as described in any one of Claims 1-10 characterized by the above-mentioned.   The method for producing a molded body having a plating film according to any one of claims 1 to 11, wherein the shape of the mineral is granular.   The method for producing a molded body having a plated film according to any one of claims 1 to 12, wherein the molded body has a surface roughness (Ra) of 1 µm or less.   The method for producing a molded body having a plating film according to any one of claims 1 to 13, wherein the strong acid does not contain hexavalent chromic acid.   The plating film according to claim 1, further comprising contacting an alcohol treatment liquid with the molded body before contacting the electroless plating solution with the molded body. The manufacturing method of the molded object which has.   The method for producing a molded body having a plating film according to claim 15, wherein the alcohol treatment liquid is contacted with the molded body after the strong acid is brought into contact with the molded body.   The method for producing a molded body having a plating film according to claim 15 or 16, wherein the alcohol treatment liquid softens the block copolymer.   The alcohol treatment liquid is ethanol, 1-propanol, 2-propanol, 1,2-butanediol, 1,3-butanediol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 1- Ethoxy-2-propanol, 2-methyl-2,4-pentanediol, 2- (2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethanol, 2- (2-methoxyethoxy) ethanol, ethylene glycol, The method for producing a molded body having a plated film according to any one of claims 15 to 17, comprising at least one selected from the group consisting of diethylene glycol, tetraethylene glycol, polyethylene glycol, and polypropylene glycol. .   The method for producing a molded body having a plated film according to claim 18, wherein the alcohol treatment liquid contains 1,3-butanediol.   The method for producing a molded body having a plated film according to any one of claims 1 to 19, wherein the hydrophilic segment of the block copolymer is a polyether.   The method for producing a molded body having a plated film according to any one of claims 1 to 20, wherein the metal fine particles contain palladium.

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