JP2015143382A - Resin molding and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin molding high in rigidity, heat resistance and chemical resistance and capable of obtaining reliability over a long term in a severe environment such as a vehicle interior.SOLUTION: The resin molding has a first part having a plating film formed on a surface and a second part without a plating film formed on a surface. The first part includes a first thermoplastic resin, a block copolymer having a hydrophilic segment and metal fine particles, and the second part includes a second thermoplastic resin. The water absorption rate of the first part is 0.5 wt.% or more and 3.0 wt.% or less when immersed in water at 23°C for 24 hours, and the water absorption rate of the second part is 2.0 wt.% or less.

Description

  The present invention relates to a resin molded body in which a plating film is partially formed and a manufacturing method thereof.

  A wet plating method is known as a method for forming a metal film on a resin molded body at low cost. As a method of manufacturing a resin part partially formed with a plating film using a wet plating method, a method of performing masking has been common. However, the masking process and the masking peeling process are factors that increase the cost.

  As a method for producing a resin part partially formed with a plating film without masking, an integrally molded product made of acrylonitrile / butadiene / styrene copolymer resin (ABS resin) and polycarbonate (PC) or acrylic resin ( Hereinafter, a method of performing a plating process on an “ABS / PC integral molded product” as appropriate is proposed (Patent Document 1). In the conventional wet plating method, plating that roughens the surface of the resin molded body 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 resin molded body. Perform pre-processing. In the ABS resin, the butadiene rubber component is selectively eroded by the etching solution, and wet plating becomes possible. On the other hand, since PC or acrylic resin has etching resistance, it is not affected by the etching solution and the wettability of the plating solution is low. For this reason, even if the ABS / PC integrated molded product is immersed in the plating solution without masking, a plating film is formed only on the ABS resin, and no plating film is formed on the PC or acrylic resin.

  As another method of manufacturing resin parts with a partially plated film, a two-color molding method using a resin containing a metal catalyst for electroless plating and a resin that does not contain a metal catalyst is also proposed. (Patent Document 2). According to this method, it is possible to form the plating film only on the site containing the metal catalyst.

  In addition, instead of partially forming a plating film on an integrally molded product, a molded body having a plating film and a molded body having no plating film are manufactured separately and then partially plated to assemble. A method of manufacturing a resin part on which a film is formed is also performed.

JP 2008-290295 A Japanese Patent No. 3004689

  However, in the method disclosed in Patent Document 1, usable resins are limited to ABS resin, PC, and acrylic resin. This is because, in the conventional electroless plating method disclosed in Patent Document 1, there is a possibility that the plating catalyst grows due to surface adsorption of the plating catalyst on a general-purpose resin other than PC and acrylic resin.

  ABS resin has low mechanical strength and heat resistance, PC has low chemical resistance, and acrylic resin has low heat resistance. Therefore, it has been difficult to use the ABS / PC integrated molded product as a resin part that requires long-term reliability in a harsh environment such as an automobile interior. In addition, in resin parts, there may be a demand for a high-quality appearance with matte in a portion where a plating film is not formed, but such an appearance cannot be obtained for a part formed by PC. It was. Furthermore, the conventional electroless plating method disclosed in Patent Document 1 has a problem of high environmental load because hexavalent chromic acid, permanganic acid, or the like is used in etching as a pretreatment for plating.

  Unlike the method disclosed in Patent Document 1, the method disclosed in Patent Document 2 can form a molded body using a resin having high rigidity, heat resistance, and chemical resistance, such as polyphenylene sulfide. However, it is necessary to knead a large amount of expensive metal catalyst in the portion where the plating film is formed (about several hundred ppm), which is uneconomical. Further, similar to the method disclosed in Patent Document 1, it is necessary to etch the surface of the portion where the plating film is formed using a chemical having a high environmental load. As a result, the surface of the portion where the plating film is not formed is also etched, and it has been difficult to manufacture a resin component that requires design.

  Resin parts manufactured by assembling, not an integrally molded product, are expensive, and there is a risk that the design property may be lowered due to a step at the interface between the part having the plating film and the part not having the plating film. There is a possibility that a squeak noise may occur, and further, the chemical resistance of the interface is also a problem.

  The present invention solves the above-described problems, and has high rigidity, heat resistance and chemical resistance. For example, it can ensure long-term reliability in a harsh environment such as an automobile interior and has excellent design. A resin component partially formed with a plating film is provided at low cost.

  According to the first aspect of the present invention, the resin molded body has a first portion where the plating film is formed on the surface and a second portion where the plating film is not formed on the surface, The first part includes a first thermoplastic resin, a block copolymer having a hydrophilic segment, and metal fine particles, and the second part includes a second thermoplastic resin, which is in water at 23 ° C. The water absorption rate of the first part when immersed for 24 hours is 0.5% by weight or more and 3.0% by weight or less, and the water absorption rate of the second part is 2.0% by weight or less. A resin molded body characterized by the above is provided.

  In this embodiment, the first thermoplastic resin may be polyamide. Moreover, 5 GPa or more may be sufficient as the bending elastic modulus in normal temperature of a site | part with much occupied volume in the said resin molding among a 1st site | part and a 2nd site | part. The second thermoplastic resin may contain polyamide or may contain polypropylene.

  In this aspect, the second part may not contain the metal fine particles. The metal fine particles contained in the first part may be palladium, and the metal fine particles may be contained in the first part in an amount of 1 to 50 ppm by weight. Moreover, in this aspect, the 1st site | part and the 2nd site | part may be shape | molded integrally. The plating film may contain nickel phosphorus or nickel boron. In the first portion of this embodiment, the domain of the block copolymer containing the metal fine particles may be present in the matrix made of the first thermoplastic resin.

  According to a second aspect of the present invention, there is provided a method for producing a resin molded body according to the first aspect, wherein the block copolymer and resin pellets containing the metal fine particles are prepared, and the first heat Plasticizing and melting the plastic resin and the resin pellets to form a first molten resin, plasticizing and melting the second thermoplastic resin to form a second molten resin, and first melting Molding a resin member having a first part made of the first molten resin and a second part made of the second molten resin using the resin and the second molten resin; and the resin member A method for producing a resin molded body comprising forming the plating film on the surface of the first part is provided.

  In this aspect, the resin pellet is prepared by bringing pressurized carbon dioxide in which the metal fine particles are dissolved or dispersed into contact with the block copolymer and allowing the metal fine particles to permeate the block copolymer. May be included. Further, the manufacturing method of this aspect may include molding the resin member by two-color molding, and immersing the entire resin member in an electroless plating solution to form the plating film only on the surface of the first part. May be formed.

  The resin molded body of the present invention having the first part where the plating film is formed on the surface and the second part where the plating film is not formed on the surface has a clear contrast with the presence or absence of the plating film and has a good design Are better. Moreover, the rigidity, heat resistance, and chemical resistance are high, and long-term reliability can be secured in a harsh environment such as an automobile room.

It is a figure of the resin molding which has the plating film of embodiment. It is a cross-sectional schematic diagram of the resin molding which has the plating film of embodiment. It is a flowchart explaining the manufacturing method of the resin molding of embodiment. (A)-(e) is a figure explaining the two-color molding of the resin member of embodiment.

[Resin molding]
The resin molding of the present invention is a resin molding in which a plating film is partially formed. As an embodiment of the present invention, first, an evaluation sample resin molded body 100 shown in FIG. The resin molded body 100 has a first portion 101 where the plating film 103 is formed on the surface and a second portion 102 where the plating film is not formed on the surface.

  The first portion 101 where the plating film 103 is formed on the surface includes a first thermoplastic resin, a block copolymer having a hydrophilic segment, and metal fine particles. The first thermoplastic resin preferably contains polyamide. Since polyamide has high water absorption, penetration of the plating solution is promoted and the plating film grows stably in the first part. Moreover, since polyamide is excellent in rigidity, heat resistance and chemical resistance, the rigidity, heat resistance and chemical resistance of the resin molded product can be ensured. The main component of the first thermoplastic resin is preferably polyamide. For example, the polyamide is preferably contained in the first thermoplastic resin in an amount of 50% by weight to 100% by weight, and 80% by weight to 98% by weight. More preferably it is included. The polyamide contained in the first 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, and the like can be used. Nylon 6 which has high water absorption and easily swells is more preferable because of the ease of forming a plating film.

  The first thermoplastic resin may or may not contain a resin other than polyamide. The resin other than polyamide is not particularly limited, and polycarbonate, polypropylene, polymethyl methacrylate and the like can be used. The first thermoplastic resin may be a non-reinforced resin not containing a filler such as mineral or glass fiber, a mineral reinforced resin containing mineral or the like, a fiber containing glass fiber (GF) or carbon fiber or the like. It may be a reinforced resin. In order to enhance the designability, it is preferable to use a mineral reinforced resin having a spherical particle shape and inconspicuous filler, and in the case where it is necessary to increase the rigidity, it is preferable to use a glass fiber reinforced resin. Further, when the thickness of the first portion is thick, it is preferable to use a fiber reinforced resin because the movement of the resin is increased in the thermal shock test and the plating film may be broken. The content of the filler contained in the first thermoplastic resin can be appropriately determined according to the use of the resin molded body and the required strength. For example, the filler is preferably contained in the first thermoplastic resin in an amount of 5 wt% to 80 wt%, more preferably 10 wt% to 60 wt%. Moreover, in order to improve the adhesiveness of the 1st site | part and the 2nd site | part, the 1st thermoplastic resin may contain various compatibilizing materials and adhesive materials, such as maleic anhydride modified polypropylene (PP-MAH). it can.

  Next, a block copolymer having a hydrophilic segment contained in the first portion 101 (hereinafter referred to as “block copolymer” as appropriate) will be described. The block copolymer has a hydrophilic segment and another segment different from the hydrophilic segment (hereinafter referred to as “other segment” as appropriate). The block copolymer tends to move along with the metal fine particles toward the surface of the first portion 101 during the molding process or after molding, and segregate near the surface of the molded body together with the metal fine particles.

  An anionic segment, a cationic segment, and a nonionic segment can be used for the hydrophilic segment of the block copolymer of this embodiment. Examples of anionic segments include polystyrene sulfonic acid, cationic segments include quaternary ammonium base-containing acrylate polymer systems, and nonionic segments include polyether ester amide systems, polyethylene oxide-epichlorohydrin systems, and polyether ester systems. Can be mentioned.

  As the block copolymer of the present embodiment, it is preferable that the hydrophilic segment is a nonionic segment having a polyether structure because the heat resistance of the molded product is easily secured. Examples of the polyether structure include an oxyalkylene group having 2 to 4 carbon atoms of alkylene, such as an ethylene group, a propylene group, a trimethylene group, and a tetramethylene group, a polyether diol, a polyether diamine, and these Modified products and polyether-containing hydrophilic polymers are included, and polyethylene oxide is particularly preferable.

  The other segment of the block copolymer of this embodiment is arbitrary as long as it is a hydrophobic segment rather than a hydrophilic segment, and the kind according to the objective can be selected. For example, polyamides such as nylon 6 and nylon 12, polyolefin, polylactic acid, polyethylene and the like can be used.

  In this embodiment, a commercial item may be used for a block copolymer. The block copolymer of this embodiment may be commercially available as a resin-kneaded polymer type antistatic agent because it segregates (orients) near the surface of the molded body. For example, Pelestat (registered trademark) or Peletron (registered trademark) manufactured by Sanyo Chemical Industries, Ltd. can be used as the block copolymer of this embodiment. Pelestat (registered trademark) NC6321, 1251 manufactured by Sanyo Chemical Industries, Ltd. is a block copolymer obtained by copolymerizing a hydrophilic segment polyether and another segment nylon with an ester bond.

  Content of the block copolymer in the 1st site | part 101 is arbitrary, and can be suitably determined based on the kind of 1st thermoplastic resin, the kind of block copolymer, the use of a resin molding, etc. For example, the block copolymer is preferably contained in the first portion 101 in an amount of 1 to 30% by weight, more preferably 1 to 20% by weight, and even more preferably 3 to 15% by weight. . When the block copolymer is contained in the first part 101 at 1% by weight or more, the permeability of the plating solution can be sufficiently increased, and when it is contained at 30% by weight or less, the heat resistance and mechanical strength of the molded body are increased. The physical properties such as are not greatly impaired.

  Next, the metal fine particles contained in the first part 101 will be described. The metal fine particles function as a metal catalyst for electroless plating for forming the plating film 103 on the surface of the first portion 101 in the manufacturing process of the resin molded body. The metal fine particles are preferably metals capable of functioning as an electroless plating catalyst, for example, fine particles such as Pd, Ni, Pt, and Cu, and palladium fine particles are more preferable from the viewpoint of catalyst stability of electroless plating.

  The metal fine particles of this embodiment are preferably nanoparticles having a particle size of 10 nm or less. Since nanoparticles having a particle size of 10 nm or less have a large surface area and high catalytic activity, a plating film can be stably formed with a low concentration of catalyst, and the cost can be reduced.

  It is preferable that 1-50 weight ppm of metal microparticles are contained in the 1st site | part 101, and it is still more preferable that 5-20 weight ppm is contained. The content of the metal fine particles in the first portion 101 is such that a part of the first portion 101 is dissolved in an organic solvent, and the amount of metal such as Pt is measured using ICP (Inductively Coupled Plasma) emission analysis. It is calculated | required by measuring. When the content of the metal fine particles is small, the amount of metal such as Pt can be measured using ICP-MS (inductively coupled plasma mass spectrometer).

  The 2nd site | part 102 in which the plating film is not formed in the surface shown in FIG. 1 contains the 2nd thermoplastic resin. The second thermoplastic resin is not particularly limited, and the resins listed as the first thermoplastic resin can be used depending on the application of the resin molded body. Similarly to the first thermoplastic resin, the second thermoplastic resin may be a non-reinforced resin or a reinforced resin. In addition, various compatibilizing materials and adhesive materials may be mixed in order to improve the adhesion between the first part and the second part.

  From the viewpoint of improving the rigidity, heat resistance and chemical resistance of the resin molded body, the second thermoplastic resin is preferably a polyamide excellent in these characteristics. In particular, by using a glass fiber reinforced resin, the second portion can also obtain rigidity close to aluminum.

  Moreover, it is preferable that a 2nd thermoplastic resin contains a polypropylene (PP) from a viewpoint of the chemical-resistant improvement of a resin molding, weight reduction, and cost reduction. In the case where the first thermoplastic is polyamide, from the viewpoint of improving the adhesion between the first part and the second part, the second thermoplastic resin is a maleic anhydride obtained by modifying a part of polypropylene. It may be a modified polypropylene (PP-MAH), a mixture of PP and PP-MAH, or an alloy resin of polyamide (PA) / PP.

  When it is desired to add a matte decoration to the second portion where the plating film is not formed, the second thermoplastic resin is preferably a crystalline resin. Examples of the crystalline resin include resins such as nylon, polyethylene, polypropylene, polyacetal, polyphthalamide, polyphenylene sulfide, polybutylene terephthalate, and polyethylene terephthalate.

  As the second thermoplastic resin, one kind of resin may be used alone, or two or more kinds of resins may be mixed and used. When two or more types of resins are used in combination, from the viewpoint of improving the adhesion between the first part and the second part, the second thermoplastic resin is a common resin with the first thermoplastic resin. It is preferable to include. For example, when the first thermoplastic resin is polyamide, the second thermoplastic resin preferably contains 5% by weight or more of polyamide.

  The second part may be a foam molded article. By foaming the second part, a resin molded body having both heat insulating properties, strength, and dimensional accuracy can be obtained. The resin molded body in which the second part is foamed includes, for example, building material parts such as resin sashes, high-rigidity automobile parts such as door knobs, shift levers, paddle shifts, air conditioner blades, automobiles such as front grills, garnishes, and inner door handles. It can be used as a ready-made plating part, a camera casing, a lens barrel of an interchangeable lens or a part thereof, a home appliance part such as a flat-screen TV, a personal computer, an air conditioner, and a refrigerator.

  Since the second portion 102 does not have a plating film on the surface, it is not necessary to include the metal fine particles that act as a catalyst for electroless plating and the block copolymer that improves the electroless plating reaction.

  In the present embodiment, the water absorption rate of the first part when immersed in water at 23 ° C. for 24 hours is 0.5% by weight or more and 3.0% by weight or less, and the water absorption rate of the second part is 2.0% by weight or less. The said water absorption of a 1st site | part and a 2nd site | part can be measured by the method described in the Example mentioned later, for example. When the first portion has a water absorption rate of less than 0.5% by weight when immersed in water at 23 ° C. for 24 hours, the plating reactivity decreases, and the water absorption rate exceeds 3.0% by weight. The difference between the swelling of the resin during plating and the shrinkage of the resin after plating increases, and there is a possibility that problems such as cracking of the plating film may occur. Also, if the water absorption rate of the first part exceeds 3.0% by weight, the plating solution may accumulate at the interface between the first part and the second part during electroless plating, and peeling may occur at the interface between the two resins. There is also. On the other hand, in the second part, when the water absorption rate after being immersed in water at 23 ° C. for 24 hours exceeds 2.0% by weight, water is immersed from the second part to the first part, and the plating film interface May occur. Moreover, if the water absorption rate of the second part is large, the dimensional accuracy of the resin molded body also decreases due to water absorption. As described above, as a result of intensive studies by the present inventors, when electroless plating is performed on a resin molded body composed of the first part and the second part, the water absorption rate of both parts must be optimized. It has been found that there is a problem in the reliability of parts using resin molded bodies. The water absorption rate of the first part when immersed in water at 23 ° C. for 24 hours is 0.5% by weight or more and 3.0% by weight or less, and the water absorption rate of the second part is 2.0% by weight or less. By doing so, it is possible to ensure long-term reliability of parts using resin molded bodies.

  Furthermore, the water absorption rate of the first part when immersed in water at 23 ° C. for 24 hours is preferably 0.5 wt% or more and 2.0 wt% or less. The lower limit of the water absorption rate of the second part is not particularly limited and is preferably as low as possible. However, from the viewpoint of suppressing peeling due to a difference in water absorption rate with the first resin, 0.1% by weight or more is preferable. preferable.

  In the resin molded body of the present embodiment, the first part and the second part have the water absorption rate in the specific range described above, and the difference in the water absorption rate between the two parts is 2.9% by weight or less. And is more preferably 2.5% by weight or less. If the difference in water absorption between the two parts is 2.9% by weight or less, the difference in expansion coefficient between the two parts due to water absorption is also small, so that the plating film is peeled off and the first part and the second part are separated. Can be suppressed. The water absorption rate of the first part and the second part may be larger than the first part as long as the water absorption rate of the second part is within the specific range described above. Conversely, the water absorption rate of the first part may be larger than that of the second part. The “difference between the water absorption rates of the two parts” is a difference obtained by subtracting a small value from a large value of the water absorption rate of the first part and the water absorption rate of the second part.

  The resin molded body of the present embodiment preferably has a bending elastic modulus at room temperature of a portion having a larger occupied volume in the resin molded body of the first portion and the second portion at 5 GPa or more, More preferably, it is 10 GPa or more. These bending elastic moduli at normal temperature are measured according to the test method ISO178. If the bending elastic modulus at room temperature of the part with the larger occupied volume in the resin molded body is 5 GPa or more, it can be used for, for example, an interior part of an automobile requiring high rigidity. Since glass fiber (GF) reinforced nylon mixed with a large amount of glass fiber has high rigidity, it is preferably used as a thermoplastic resin contained in a portion having a larger occupied volume in the resin molded body. In the resin molded body, the first part and the second part may occupy a large volume of either part, and are determined based on the use, design, or the like of the resin molded body.

  The plating film 103 formed on the surface of the first portion 101 preferably contains nickel, and particularly preferably contains nickel phosphorus or nickel boron. This is because these plating films can be easily formed by an electroless plating method. The plating film 103 is formed on the surface of the first portion 101 using metal fine particles as an electroless plating catalyst. For this reason, in this embodiment, the highly reliable plating film 103 can be formed on the surface of the first portion 101 without using an etching process with a high environmental load. On the other hand, since the second portion 102 does not contain an electroless plating catalyst, a plating film is not formed even when it comes into contact with the electroless plating solution. Thereby, the resin molding 100 can obtain the partial plating film 103 with clear contrast of the presence or absence of the plating film at a low cost without using the masking process. In addition, for the purpose of improving the use and design of the resin molded body, the plating film 103 is a laminate in which electrolytic copper plating, electrolytic nickel plating, electrolytic trivalent chromium plating, etc. are further laminated on the electroless plating film. There may be.

  The resin molded body 100 of this embodiment preferably does not undergo plastic deformation when left in an environment of 140 ° C. to 150 ° C. for 48 hours. By not plastically deforming, swelling, cracking, peeling, etc. of the plating film 103 can be suppressed, and long-term reliability can be ensured in a harsh environment where the temperature is high such as in an automobile interior.

  Next, a cross-sectional structure near the surface of the first part of the present embodiment will be described. In the present specification, “near the surface of the first part” means an area inside the first part and close to the surface. The extent to which “near the surface of the first part” means the region from the surface of the first part depends on the type of the first thermoplastic resin, block copolymer and metal fine particles. Although it is different, for example, it is a region having a depth of 0.1 to 10 μm from the surface of the molded body.

  As shown in FIG. 2, the vicinity of the surface of the first portion 101 of this embodiment is a domain (island) of a block copolymer containing metal fine particles 106 in a first thermoplastic resin matrix (sea) 104. 105 has a matrix-domain structure (sea-island structure). Since the block copolymer has a hydrophilic segment, it moves along with the metal fine particles toward the surface of the first part, and tends to segregate near the surface of the first part together with the metal fine particles. For this reason, there are more domains (islands) 105 of the block copolymer near the surface of the first part 101 than in the central part of the first part 101. As a result, the concentration of the metal fine particles inside the first part that does not contribute to the plating reaction can be relatively lowered, the waste of material can be saved, and the material cost can be suppressed.

  In the first portion 101 of the present embodiment, the block copolymer is oriented in stripes in the vicinity of the surface (is unevenly distributed), so that the surface of the molded body is hydrophilized by the hydrophilic segment of the block copolymer. For this reason, it is considered that the penetration of the plating solution and the growth of the plating film are promoted. As a result, the first portion 101 of this embodiment has a good throwing power of the plating film, and the plating film is 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. Further, the plating solution easily penetrates into the hydrophilic portion. Since the metal fine particles 106 are present in a large amount in the domain (island) 105 of the hydrophilic block copolymer, the plating solution is more likely to come into contact with the metal fine particles 106 and the plating efficiency is considered to be improved.

  On the other hand, since the block copolymer is unevenly distributed in the vicinity of the surface of the first part 101, only the vicinity of the surface of the first part 101 is hydrophilized, and the water absorption (macroscopic water absorption) of the entire first part 101 is achieved. The effect is small. Therefore, brittle fracture of the first part 101 in the plating solution can be suppressed, and the mechanical strength of the molded body is not reduced. Further, since the block copolymer of the present embodiment is a polymer, unlike a normal low molecular surfactant, it remains in the vicinity of the surface without falling off from the surface of the molded body, and the first portion 101 as described above. The surface vicinity of can be made hydrophilic. A normal low molecular surfactant has a high possibility of falling off the surface of the molded body, and an effect equivalent to that of the block copolymer of the present invention cannot be expected.

  Further, metal particles 107 made of a metal having the same composition as the plating film (electroless plating film) 103 exist in the vicinity of the surface of the first portion 101 shown in FIG. This is because, during electroless plating, the plating solution penetrates near the surface of the first portion 101 and comes into contact with the metal fine particles 106 to generate metal particles 107. The metal particles 107 are connected to form a film, and a plating film (electroless plating film) 103 is finally formed. In this way, the plating film 103 grows while expanding the molded body from the inside of the molded body. Therefore, a part of the metal particles 107 is connected to the plating film 103 in the vicinity of the surface of the first part 101. In other words, the electroless plating film 103 is formed on the first part 101 in a state where it has penetrated into the first part 101 (a state in which a part of the plating film has penetrated into the molded body), and has high adhesion due to the anchor effect. Showing gender.

  As described above, the resin molded body of the present embodiment has a wide selection range of the first thermoplastic resin and the second thermoplastic resin, has high rigidity, heat resistance, and chemical resistance, and is a plating film. The presence / absence of contrast is high and the design is good. Since masking or the like is not used, it can be provided at a low manufacturing cost. In addition, since the resin molded body 100 of the present embodiment is an integrally molded product, there is no step at the interface between the portion having the plating film and the portion not having the plating film, excellent design, and chemical resistance at the interface. There is no risk of decline.

[Method for producing resin molded body]
Next, a method for manufacturing the resin molded body 100 shown in FIG. 1 will be described with reference to the flowchart shown in FIG.

(1) Production of Master Batch (Resin Pellets) First, resin pellets in which metal fine particles are dispersed in a block copolymer are prepared (step S1). In the present specification, the “resin pellet” means a small lump (pellet) so that the resin can be easily processed, and the size and shape vary depending on the use of the pellet, for example, about 3 to 5 mm. It is a small piece of particulate and columnar resin. Moreover, in the manufacturing method of this embodiment, the resin pellet containing a block copolymer and metal microparticles corresponds to a master batch, and the first thermoplastic resin corresponds to a base resin into which the master batch is blended. 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 molding by adding metal fine particles, which are functional materials, directly to the base resin. Moreover, when a masterbatch is used, it has the advantage that the molded object containing a metal microparticle can be manufactured using a general purpose molding machine.

  The master batch (resin pellet) can be produced by any method. For example, the master batch (resin pellet) can be produced by the production method disclosed in International Patent Publication No. WO2013 / 129659. It is preferable to include a step of infiltrating the fine metal particles into the block copolymer by bringing carbon (hereinafter referred to as “mixed pressurized fluid” if necessary) into contact with the block copolymer. Since the method using pressurized carbon dioxide does not require an organic solvent, the environmental load is low. Further, the pressurized carbon dioxide promotes uniform dispersion of the metal fine particles in the block copolymer, and can significantly reduce the particle size of the metal fine particles. It is considered that the metal fine particles are more easily moved to the surface of the molded body along with the block copolymer because the metal fine particles are uniformly dispersed without being aggregated. As a result, when a molded body having a plating film is manufactured using resin pellets manufactured using pressurized carbon dioxide, a uniform and high-quality plating film can be obtained. Although it is possible to produce resin pellets 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. The metal fine particles used in this embodiment are preferably dissolved in pressurized carbon dioxide. Therefore, as metal fine particles, hexafluoroacetylacetonatopalladium (II) metal complex, platinum dimethyl (cyclooctadiene), bis (cyclopentadienyl) nickel, bis (acetyl), which have high solubility in pressurized carbon dioxide Acetate) Metal complexes such as palladium are preferred.

  In this embodiment, a master batch (resin pellet) is manufactured by batch processing using a high-pressure vessel. First, a pellet-shaped block copolymer (raw material pellet) and a metal complex are accommodated in a high-pressure vessel, and pressurized carbon dioxide is introduced therein. After the introduction of the pressurized carbon dioxide, the inside of the high-pressure vessel is kept in a pressurized state for a certain time. The metal fine particles are dissolved in the pressurized carbon dioxide, the pressurized carbon dioxide in which the metal fine particles are dissolved contacts the block copolymer, and the metal fine particles penetrate into the block copolymer together with the pressurized carbon dioxide. Thereby, a resin pellet (master batch) in which metal fine particles are dispersed in the block copolymer is obtained. After a certain period of time, the pressurized carbon dioxide inside the high-pressure vessel is exhausted outside the vessel, and the resin pellets (master batch) are taken out from the high-pressure vessel. Although depending on various conditions of the batch processing, in this embodiment, the amount of the metal fine particles accommodated in the metal container permeating into the block copolymer (raw material pellet) is 20 to 80 of the charged amount. %, Not all metal fine particles penetrate into the block copolymer. However, the metal fine particles that do not penetrate into the block copolymer can be recovered by being discharged out of the high-pressure vessel together with the pressurized carbon dioxide and separated from the pressurized carbon dioxide.

  The content of the metal fine particles in the resin pellet (masterbatch) is arbitrary and can be appropriately determined in consideration of the type of metal fine particles, the type of block copolymer, the use application of the resin parts, etc. From the viewpoint of plating reactivity, for example, 10 ppm by weight to 2000 ppm by weight is preferable, and 50 ppm by weight to 500 ppm by weight is more preferable.

  As the pressurized carbon dioxide used for the production of the resin pellets, pressurized carbon dioxide in a liquid state, a gas state, or a supercritical state can be used. These pressurized carbon dioxides are harmless to the human body, are excellent in diffusibility into the block copolymer, and can be easily removed from the block copolymer. The pressure and temperature of the pressurized carbon dioxide introduced into the high-pressure vessel are arbitrary, but it is preferable to use liquid carbon dioxide or supercritical carbon dioxide 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. Note that the pressure and carbon dioxide in which metal fine particles are dissolved or dispersed tend to fluctuate in temperature and pressure. Therefore, the above-mentioned state, temperature, and pressure of pressurized carbon dioxide are values of the state, pressure, and temperature of pressurized carbon dioxide in a stable state before being introduced into the high-pressure vessel.

  In this embodiment, after the introduction of the pressurized fluid, the time for maintaining the inside of the high-pressure vessel in a pressurized state can be arbitrarily determined in consideration of the type of block copolymer, the type of metal fine particles, etc. Minutes to 120 minutes are preferred.

  As described above, in this embodiment, resin pellets (master batch) are manufactured by batch processing using a pressurized container, but resin pellets (master batch) are manufactured by other methods using pressurized carbon dioxide. May be. Examples of other methods using pressurized carbon dioxide include the following methods. First, the block copolymer is plasticized and melted in a plasticizing cylinder of an extruder, and pressurized carbon dioxide (mixed pressurized fluid) in which metal fine particles are dissolved is introduced into the plasticizing cylinder. The block copolymer is brought into contact with the mixed pressurized fluid. Then, the block copolymer mixed with the metal fine particles is extruded and then pulverized to obtain resin pellets (master batch) formed from the block copolymer mixed with the metal fine particles.

  In addition, the resin pellet (masterbatch) used by this embodiment demonstrated above contains only a block copolymer as a thermoplastic resin, However, a resin pellet (masterbatch) may include another thermoplastic resin as needed. May be included. As such a thermoplastic resin, the same kind of resin as the first thermoplastic resin described above can be used.

(2) Molding of resin member In this embodiment, a resin member having a first portion 101 and a second portion 102 by a two-color molding method using a general-purpose two-color molding machine 200 shown in FIG. Is molded. Here, the resin member means a member obtained by removing the plating film 103 from the resin molded body 100 shown in FIG.

  First, the first thermoplastic resin and the resin pellet (masterbatch) are plasticized and melted in the first plasticizing cylinder 204 of the two-color molding machine 200 shown in FIG. (Step S2 in FIG. 3), the second thermoplastic resin is plasticized and melted in the second plasticizing cylinder 205 to form the second molten resin (Step S3). Next, as shown in FIG. 4B, the first molten resin is injected into the cavity 202 formed in the mold 201 shown in FIG. 1 part 101 is formed.

  A core back is performed in the mold 201 by a hydraulic drive mechanism (not shown), and the cavity 202 in the mold 201 is widened to form a new space 203 as shown in FIG. Then, as shown in FIG. 4 (d), the second molten resin is transferred from the second plasticizing cylinder 205 to a new space 203 in the cavity 202 while holding the first portion 101 in the cavity 202. Inject. Thereby, the 2nd site | part 102 connected to a 1st site | part is shape | molded in the metal mold | die 201, and the resin member of this embodiment is obtained (step S4 of FIG. 3). As shown in FIG. 4E, by opening the mold 201, the resin member formed from the first part 101 and the second part 102 can be taken out.

  In the two-color molding of the present embodiment, the mixing ratio of the first thermoplastic resin and the resin pellet (master batch) can be appropriately determined in consideration of the content of metal fine particles in the resin pellet (master batch). For example, the ratio of the resin pellet (masterbatch) is 1% by weight to the total amount of the resin pellet (masterbatch) and the first heat-composable resin, that is, the total weight of the first part. It is preferably 30% by weight, more preferably 1% by weight to 15% by weight. When the ratio of the resin pellets (master batch) is 1% by weight or more, the permeability and plating reactivity of the plating solution can be sufficiently increased. Physical properties such as mechanical strength are not significantly impaired.

  As described above, in the manufacturing method of the present embodiment, by using resin pellets (master batch) containing metal fine particles, a general-purpose molding machine is used to simultaneously perform molding and surface modification of the molded body. Therefore, it is not necessary to make a capital investment such as purchasing a new molding machine. Further, in the two-color molding method of the present embodiment, a method of performing core back in the cavity 201 (core back method) was used, but other known methods, for example, a first molten resin was injection molded into the cavity. Thereafter, a method may be used in which the cavity is inverted and the second molten resin is injected and filled into the cavity (inversion method). Furthermore, as long as the molding method integrates parts made of different materials, other known molding methods other than two-color molding, for example, insert molding may be used.

(3) Electroless plating The resin member obtained by the above molding method is immersed in an electroless plating solution. Thereby, the plating film 103 is formed on the surface of the first member 101, and the resin molded body 100 shown in FIG. 1 is obtained (step S5 in FIG. 3).

  As the electroless plating solution, known ones can be used, but electroless nickel phosphorous plating solution, electroless nickel boron plating solution and the like are preferable from the viewpoint that the catalyst activity is high and the solution is stable. In the present embodiment, a nickel phosphorous film that is a nickel-containing film is formed on the surface of the molded body using an electroless nickel phosphorous plating solution.

  Since the first member 101 contains fine metal particles that function as an electroless plating catalyst, it is not necessary to apply a catalyst to the surface of the molded body, and it is necessary to perform a surface treatment using a chemical with a high environmental load for applying the catalyst. There is no. On the other hand, since the second portion 102 does not contain an electroless plating catalyst, for example, even if the entire resin member is immersed in an electroless plating solution, the plating film is formed only on the surface of the first member, A plating film is not formed on the second portion 102. Thereby, the partial plating film 103 with a clear contrast of the presence or absence of the plating film can be formed on the surface of the resin molded body 100 at a low cost without using the masking process. In addition, for the purpose of improving the use and design of the resin molded body, a plating film such as electrolytic copper plating, electrolytic nickel plating and electrolytic trivalent chromium plating is further laminated on the plating film formed by electroless plating. Also good.

  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.

  In Examples 1 to 5 and Comparative Examples 1 to 4 described below, a resin molded body 100 shown in FIG. 1 as an evaluation sample was manufactured by the following method. Table 1 shows the materials used for manufacturing the resin molded body 100 and the evaluation results of the resin molded body 100.

[Example 1]
<Manufacture of resin members>
(1) Production of master batch Resin pellets (master batch) in which metal fine particles were dispersed in a block copolymer were produced by batch processing using a high-pressure vessel. First, in a high-pressure vessel adjusted to 40 ° C., pelletized block copolymer (raw material pellet) made by Sanyo Chemical Industries, Pelestat (registered trademark) PL1251, and metal complex hexafluoroacetylacetonato palladium (II ) The complex was accommodated. The ratio of the metal complex to the block copolymer (raw material pellet) was 2000 ppm by weight. The ratio of palladium in the metal complex to the block copolymer (raw material pellets) was about 400 ppm by weight.

  Liquid carbon dioxide having a pressure of 15 MPa was introduced as pressurized carbon dioxide into the high-pressure vessel in which the block copolymer and the metal complex were accommodated. After the introduction, the inside of the high-pressure vessel was maintained in a pressurized state for 1 hour. Thereafter, the pressurized carbon dioxide inside the high-pressure vessel was exhausted outside the vessel and the pressure was reduced, and the resin pellet (master batch) was taken out from the high-pressure vessel. The resin pellets changed from the white color of the raw material pellets to yellow, which is the color of the metal complex.

  The obtained resin pellet was dissolved in concentrated hydrochloric acid using a microwave dissolving apparatus, and the amount of palladium in the resin pellet was measured with an ICP emission spectrometer. The content of palladium in the resin pellets was 190 ppm by weight. From this result, it was found that less than 50% by weight of palladium contained in the metal complex introduced into the high-pressure vessel penetrated into the raw material pellets. Next, the cross section of the resin pellet was observed using TEM. In TEM, palladium could not be detected in the cross section of the resin pellet. From this result, it is presumed that the palladium in the resin pellet is present at an atomic level below the detection limit of TEM.

(2) Two-color molding Using a two-color molding machine manufactured by Nippon Steel, J180AD-2M, the first two-color molding method of the core back method shown in FIGS. The resin member having the part 101 and the second part 102 was molded. Here, the resin member means a member obtained by removing the plating film 103 from the resin molded body 100 shown in FIG. As the first thermoplastic resin, glass fiber reinforced nylon 6 containing 45% by weight of glass fiber (Toray, Amilan CM1011G45), and as the second thermoplastic resin, glass fiber reinforced nylon 6 containing 60% by weight of glass fiber (manufactured by Toyobo) , Gramide TY791G60), and the resin pellets produced above were used as resin pellets (masterbatch).

  In the molding of the first part 101, the ratio of the resin pellets (master batch) to the total amount of the resin pellets (master batch) and the first heat-composable resin was 5% by weight. As described above, since the proportion of palladium in the resin pellets (master batch) used in this example was 190 ppm by weight, the proportion of palladium in the first portion 101 was 190 × 0.05 = It can be calculated as 9.5 ppm by weight. When the proportion of palladium in the first portion 101 of the resin member obtained in this example was measured by ICP-MS, it was confirmed that the error of the calculated value was within 10%.

(3) Formation of plating film The molded resin member was immersed in an aqueous 2.5N hydrochloric acid solution at room temperature for 1 minute, then immersed in an aqueous solution of 1,3-butanediol (75% by volume) at 80 ° C. for 5 minutes, and then 85 It was immersed for 10 minutes in an electroless nickel plating solution (Okuno Pharmaceutical Co., Ltd., Nicolon DK). As a result, a nickel phosphorous plating film having a thickness of 1 μm was formed only at the first portion. The time (plating time) required until the entire surface of the first part was covered with the nickel phosphorus plating film was 5 minutes. Next, an electrolytic copper plating film of 10 μm, an electrolytic nickel plating film of 10 μm, and an electrolytic trivalent chromium plating of 0.2 μm are laminated in this order on the nickel phosphorus plating film by a general-purpose method, and the resin molded body 100 shown in FIG. Got.

<Evaluation of resin molding>
(1) Water Absorption Rate of First and Second Part A first evaluation molded body having the same composition as the first part 101 and a second evaluation molded body having the same composition as the second part 102 were molded. The size of the first and second evaluation molded bodies was 10 cm × 20 cm × 0.3 cm. Next, the molded body for first and second evaluation was immersed in water at 23 ° C. for 24 hours, and the weight increase rate after immersion was determined, and these were each immersed in water at 23 ° C. for 24 hours. It was set as the water absorption rate of the 1st and 2nd site | part. The water absorption rate of the first part 101 was 1.1% by weight, and the water absorption rate of the second part 102 was 0.7% by weight. The difference between the first part and the second part is 0.4% by weight.

(2) Flexural modulus A third evaluation molded body having the same composition as that of the first portion 101 and a fourth evaluation molded body having the same composition as that of the second portion 102 were molded. The 3rd and 4th molded object for evaluation is a molded object of the dumbbell test piece shape based on test method ISO178. Next, the bending elastic modulus at room temperature of the third and fourth evaluation molded bodies was measured by a method based on the test method, and these bending elastic moduli were respectively measured at the bending points of the first and second parts. Elastic modulus was used. In this example, the flexural modulus of the first part was 13.0 GPa, and the flexural modulus of the second part was 16.0 GPa. It turned out that the 1st site | part and the 2nd site | part have a high elasticity modulus exceeding 10 GPa.

(3) Warm water test The manufactured resin molding 100 was immersed in water at 40 ° C. for 200 hours. The resin molded body 100 after immersion was visually observed and evaluated based on the following evaluation criteria.

Evaluation criteria for hot water test:
○: No peeling between the first part 101 and the second part 102.
X: There is peeling between the first portion 101 and the second portion 102.

After the hot water test, in the resin molded body 100 of this example, there was no peeling between the first part 101 and the second part 102, and the hot water test evaluation was “◯”.

(4) Thermal shock test (heat shock test)
50 cycles of a heat shock test in which the produced resin molded body 100 was alternately exposed to an atmosphere of −40 ° C. and an atmosphere of 120 ° C. were performed. The resin molded body 100 after the thermal shock test was visually observed and evaluated based on the following evaluation criteria.

Thermal shock test evaluation criteria:
A: The plating film 103 is not swollen, cracked, peeled off or the like.
C: The plating film 103 has any swelling, cracking, peeling, or the like.

In the resin molded body 100 of this example, the plating film 103 did not swell, crack, peel, etc., and the evaluation result was “A”.

  The resin molded body 100 of this example could easily form a plating film only on the first portion 101, had a clear contrast with and without the plating film, and was excellent in design. In the second portion 102, no deposition of the plating film was observed. In addition, the molded body of this example has high rigidity, heat resistance, and water resistance, and is suitable for automobile interior and exterior parts, building material parts, home appliance parts, and the like that require them. Examples of such parts include interior and exterior parts for automobiles such as inner door handles, shift levers, and air conditioner blades, resin parts for doors, and building parts such as door knobs.

[Example 2]
As the first thermoplastic resin, mineral-reinforced nylon 6 containing about 40% by weight of mineral (Toyobo, Gramide T777-02), and as the second thermoplastic resin, aromatic glass fiber containing 50% by weight of glass fiber. A resin molded body 100 shown in FIG. 1 was manufactured by the same manufacturing method using the same material as in Example 1 except that reinforced 6T nylon (manufactured by Toyobo, GLAMIDE TY791G) was used. The time (plating time) required until the entire surface of the first part was covered with the nickel phosphorous plating film was 3 minutes. Further, the proportion of palladium in the first portion 101 of this example can be calculated as 190 × 0.05 = 9.5 ppm by weight, as in Example 1. When the proportion of palladium in the first portion 101 of the resin member obtained in this example was measured by ICP-MS, it was confirmed that the error of the calculated value was within 10%.

<Evaluation of resin molding>
In the same manner as in Example 1, (1) water absorption of the first and second parts, (2) flexural modulus, (3) hot water test, and (4) thermal shock test (heat shock test) were performed. . The results are shown in Table 1.

  The resin molded body 100 of this example could easily form a plating film only on the first portion 101, had a clear contrast with and without the plating film, and was excellent in design. In the second portion 102, no deposition of the plating film was observed. In addition, the molded body of this example has high rigidity, heat resistance, and water resistance, and is suitable for automobile interior and exterior parts, building material parts, home appliance parts, and the like that require them. Further, in this example, since mineral reinforced nylon having a low thermal expansion coefficient was used as the first thermoplastic resin, it was possible to increase the glossiness of the plated film as compared with Example 1.

[Example 3]
As the first thermoplastic resin, non-reinforced nylon 6 (manufactured by Toyobo Co., Ltd., T-802), and as the second thermoplastic resin, glass fiber reinforced MXD nylon 6 containing 50% by weight of glass fiber (manufactured by Mitsubishi Engineering Plastics, Reny 1025). In the molding of the first part 101, the ratio of the resin pellet (master batch) to the total amount of the resin pellet (master batch) and the first heat-composable resin was changed to 10% by weight. A resin molded body 100 shown in FIG. 1 was manufactured by the same manufacturing method using the same material as in Example 1. The time (plating time) required until the entire surface of the first part was covered with the nickel phosphorous plating film was 1.5 minutes. Further, the proportion of palladium in the first portion 101 of this example can be calculated as 190 × 0.10 = 19 ppm by weight. When the proportion of palladium in the first portion 101 of the resin member obtained in this example was measured by ICP-MS, it was confirmed that the error of the calculated value was within 10%.

<Evaluation of resin molding>
In the same manner as in Example 1, (1) water absorption of the first and second parts, (2) flexural modulus, (3) hot water test, and (4) thermal shock test (heat shock test) were performed. . The results are shown in Table 1.

  The resin molded body 100 of this example could easily form a plating film only on the first portion 101, had a clear contrast with and without the plating film, and was excellent in design. In the second portion 102, no deposition of the plating film was observed. In addition, the molded body of this example has high rigidity, heat resistance, and water resistance, and is suitable for automobile interior and exterior parts, building material parts, home appliance parts, and the like that require them.

  In this example, non-reinforced nylon with high water absorption was used as the first thermoplastic resin, and the masterbatch content was also 10% by weight higher than those in Examples 1 and 2. As a result, the water absorption rate of the first part was as high as 2.9% by weight, the plating reactivity of the first part was improved, and the plating time was significantly shortened to 1.5 minutes. Moreover, compared with Example 2, the glossiness of the plating film was able to be improved.

  According to the study by the present inventors, when a plating film is formed on a molded body made of a non-reinforced polyamide resin having a high water absorption rate, it is known that the molded body has a large coefficient of linear expansion, so that it is difficult to withstand the heat shock test. . However, since the resin molded body 100 of the present embodiment has a high rigidity of the second part where the plating film is not formed, the movement of the second part due to heat or water absorption is restricted, and the adhesion of the plating film is reduced. Presumed to have been secured.

[Example 4]
As the first thermoplastic resin, mineral-reinforced nylon 6 containing approximately 40% by weight of the same mineral as in Example 2 (Toyobo, Gramide T777-02), and as the second thermoplastic resin, nylon 6.66 copolymer A resin molded body 100 shown in FIG. 1 was manufactured by the same manufacturing method using the same material as in Example 1 except that (Amilan CM6041-XF manufactured by Toray Industries, Inc.) was used. The time (plating time) required until the entire surface of the first part was covered with the nickel phosphorous plating film was 3 minutes. Further, the proportion of palladium in the first portion 101 of this example can be calculated as 190 × 0.05 = 9.5 ppm by weight, as in Example 1. When the proportion of palladium in the first portion 101 of the resin member obtained in this example was measured by ICP-MS, it was confirmed that the error of the calculated value was within 10%.

<Evaluation of resin molding>
In the same manner as in Example 1, (1) water absorption of the first and second parts, (2) flexural modulus, (3) hot water test, and (4) thermal shock test (heat shock test) were performed. . The results are shown in Table 1.

  The resin molded body 100 having the partial plating film of this example could easily form the plating film only on the first portion 101, had a clear contrast with and without the plating film, and was excellent in design. In the second portion 102, no deposition of the plating film was observed.

  In this example, since mineral-reinforced nylon having a low coefficient of thermal expansion was used as the first thermoplastic resin, the glossiness of the plated portion could be enhanced as in Example 2. Moreover, since the highly flexible copolymer nylon was used for the 2nd site | part which does not have a plating film, the flexible resin molding was obtained. The resin molded body 100 of the present embodiment has high flexibility as well as heat resistance and water resistance, and is suitable for automobile interior / exterior parts, building material parts, home appliance parts and the like that require them.

  According to the study by the present inventors, when a highly water-absorbing resin is used for the second part where the plating film is not formed, water accumulates at the interface between the first part and the second part in the warm water test. There is a possibility that the parts may be separated and the plating film may be broken. However, from the results of this example, it was found that the result of the hot water test was good when the water absorption rate of the second part was up to 2.0% by weight.

[Example 5]
As a first thermoplastic resin, mineral-reinforced nylon 6 containing 40% by weight of mineral (Toyobo, Gramide T777-02), glass fiber-reinforced polypropylene containing 10% by weight of glass fiber (manufactured by Prime Polymer, Prime Polypro K7000) and Using a mixture of maleic anhydride-modified polypropylene (PP-MAH) (manufactured by Sanyo Chemical Industries, Yumex 1001) as a second thermoplastic resin, glass fiber reinforced polypropylene containing 10% by weight of glass fiber (manufactured by Prime Polymer, Prime Polypropylene) K7000) and maleic anhydride modified polypropylene (PP-MAH) (manufactured by Sanyo Kasei Kogyo Co., Ltd., Umex 1001), except that a mixture of the same materials as in Example 1 was used. A resin molded body 100 was manufactured. Maleic anhydride-modified polypropylene is a compatibilizing material for enhancing the adhesion between the first part and the second part. In the molding of the first part, the proportions of mineral-reinforced nylon 6, polypropylene, maleic anhydride-modified polypropylene, and resin pellets (masterbatch) were 87% by weight, 5% by weight, 3% by weight, and 5% by weight. In the molding of the second part, the proportion of the maleic anhydride-modified polypropylene in the second thermoplastic resin was 3% by weight. The time (plating time) required until the entire surface of the first part was covered with the nickel phosphorous plating film was 3 minutes. Further, the proportion of palladium in the first portion 101 of this example can be calculated as 190 × 0.05 = 9.5 ppm by weight, as in Example 1. When the proportion of palladium in the first portion 101 of the resin member obtained in this example was measured by ICP-MS, it was confirmed that the error of the calculated value was within 10%.

<Evaluation of resin molding>
In the same manner as in Example 1, (1) the water absorption rate of the first and second parts, (2) the flexural modulus, and (3) the hot water test were performed. The results are shown in Table 1.

(4) Thermal shock test (heat shock test)
Since polypropylene is used for applications having lower heat resistance than the polyamide used in Examples 1 to 4, in this example, a thermal shock test was performed under milder conditions than the test performed in Example 1 described below. . A heat shock test in which the produced resin molded body 100 was alternately exposed to an atmosphere of −40 ° C. and an atmosphere of 80 ° C. was performed 10 cycles. The resin molded body 100 after the thermal shock test was visually observed and evaluated based on the following evaluation criteria.

Thermal shock test evaluation criteria:
B: No swelling, cracking, peeling, or the like has occurred in the plating film 103.
D: The plating film 103 has any swelling, cracking, peeling, or the like.

In the resin molded body 100 of this example, the plating film 103 did not swell, crack, peel, etc., and the evaluation result was “B”.

  The resin molded body 100 having the partial plating film of this example could easily form the plating film only on the first portion 101, had a clear contrast with and without the plating film, and was excellent in design. In the second portion 102, no deposition of the plating film was observed.

  Although the resin molded body of this example is inferior in heat resistance as compared with the molded bodies of Examples 1 to 4, polypropylene, which is the second thermoplastic resin, has high chemical resistance. Excellent chemical resistance compared to integrally molded products.

  Polypropylene has the advantages of low specific gravity, high chemical resistance, and low cost, so it has been widely used as an automotive part. However, it is chemically stable and has high adhesion. It was difficult to form a plating film. In the present invention, as in this embodiment, the plating film can be formed on a part of the molded product of polypropylene by using polyamide or the like for the portion (first portion) where the plating film is formed. Since the resin molded body of a present Example can be manufactured without a masking process or an assembly process, manufacturing cost can be restrained low. Therefore, the present invention can be applied to manufacturing interior and exterior parts of automobiles such as a front grille, an emblem, a car name mark, and a garnish at low cost.

[Comparative Example 1]
As the first thermoplastic resin, acrylonitrile / butadiene / styrene copolymer resin (ABS resin) (manufactured by Toray, Toyolac 125X82) and as the second thermoplastic resin, polycarbonate (PC) (manufactured by Teijin, Panlite L-1225Y) The resin member which has the 1st site | part 101 and the 2nd site | part 102 was shape | molded by the two-color molding method similar to Example 1 without using a resin pellet (masterbatch). Here, the resin member means a member obtained by removing the plating film 103 from the resin molded body 100 shown in FIG.

  Next, the plating film 103 was formed on the 1st site | part 101 with the general purpose method demonstrated below. First, the resin member was etched using hexavalent chromic acid. Since hexavalent chromic acid etched the butadiene component of the ABS resin and did not etch the polycarbonate, only the first portion 101 was etched. Next, application (catalyst) and activation (accelerator) of palladium colloid as a catalyst core of electroless plating are performed, and then, electroless nickel plating solution (manufactured by Okuno Pharmaceutical Co., Ltd., Nicolon DK) for 10 minutes. Soaked. The time (plating time) required until the entire surface of the first part was covered with the nickel phosphorus plating film was 1 minute. Next, an electrolytic copper plating film of 10 μm, an electrolytic nickel plating film of 10 μm, and an electrolytic trivalent chromium plating of 0.2 μm are laminated in this order on the nickel phosphorous plating film by the same method as in Example 1 and shown in FIG. A resin molded body 100 was obtained.

<Evaluation of resin molding>
In the same manner as in Example 1, (1) the water absorption rate of the first and second parts, (2) the flexural modulus, and (3) the hot water test were performed. The results are shown in Table 1.

(4) Thermal shock test (heat shock test)
A thermal shock test was performed in the same manner as in Example 1, and evaluation was performed in accordance with the same evaluation criteria as in Example 1. In the resin molded body 100 of this comparative example, the plating film 103 was peeled off. Next, a thermal shock test was performed by the same method as in Example 5, and evaluation was performed according to the same evaluation criteria as in Example 5. The results are shown in Table 1.

  In this comparative example, a plating film can be easily formed only on the first portion 101, and the contrast with and without the plating film is clear. In the second portion 102, no deposition of the plating film was observed. However, the results of the flexural modulus and the thermal shock test show that the resin molded body of this comparative example has lower rigidity and heat resistance than the resin molded bodies of Examples 1 to 4 using polyamide. It was. In addition, ABS resin and polycarbonate are known to have low chemical resistance, and the resin molded body of this comparative example is estimated to have low chemical resistance as compared with the resin molded bodies of Examples 1 to 5. Is done.

[Comparative Example 2]
A resin molded body 100 shown in FIG. 1 is produced by the same production method using the same material as in Example 1 except that non-reinforced nylon 6 (Toyobo's Gramide T-802) is used as the second thermoplastic resin. Manufactured. The time (plating time) required until the entire surface of the first part was covered with the nickel phosphorus plating film was 1.5 minutes. In the obtained resin molded body 100, some peeling occurred between the first portion 101 and the second portion 102.

<Evaluation of resin molding>
In the same manner as in Example 1, (1) water absorption of the first and second parts, (2) flexural modulus, (3) hot water test, and (4) thermal shock test (heat shock test) were performed. . The results are shown in Table 1. In addition, although the resin molded body 100 of this comparative example had some peeling generate | occur | produced between the 1st site | part 101 and the 2nd site | part 102 before implementing a warm water test, The peeling progressed and the evaluation was “x”.

  In this comparative example, a plating film can be easily formed only on the first portion 101, and the contrast with and without the plating film is clear. In the second portion 102, no deposition of the plating film was observed. However, in the resin molded body 100 obtained as described above, part of the peeling occurred between the first part 101 and the second part 102. This is presumably because the water absorption rate of the second part 102 is as high as 2.6% by weight, and water has accumulated at the interface between the first part 101 and the second part 102. From the results of Example 4 and this comparative example, it was found that the water absorption rate of the second part needs to be lower than 2.6% by weight, and preferably 2.0% by weight or less.

[Comparative Example 3]
As the first thermoplastic resin, using the same material as in Example 1 except that glass fiber reinforced MXD nylon 6 (Mitsubishi Engineering Plastics, Reny 1025) containing 50% by weight of glass fiber was used, A resin molded body 100 shown in FIG. 1 was manufactured. In the obtained resin molded body 100, the nickel phosphorus plating film was missing, and the plating film 103 did not cover the entire surface of the first part. For this reason, in this comparative example, the time (plating time) required until the entire surface of the first part was covered could not be measured.

<Evaluation of resin molding>
In the same manner as in Example 1, (1) water absorption of the first and second parts, (2) flexural modulus, (3) hot water test, and (4) thermal shock test (heat shock test) were performed. . The results are shown in Table 1.

  As described above, in this comparative example, the plating film did not grow stably, and the nickel phosphorus plating film was missing. This is presumably because the water absorption rate of the first part is too low. From this result, it was found that the water absorption rate of the first part needs to be higher than 0.4% by weight, and preferably 0.5% by weight or more.

[Comparative Example 4]
Using non-reinforced nylon 6 (Toyobo, T-802) as the first thermoplastic resin, the ratio of the resin pellet (masterbatch) to the total amount of the resin pellet (masterbatch) and the first thermosetting resin A resin molded body 100 shown in FIG. 1 was manufactured by the same manufacturing method using the same material as in Example 1 except that the content was 15 wt%. The time (plating time) required until the entire surface of the first part was covered with the nickel phosphorous plating film was 1.2 minutes. In the resin molded body 100 of this comparative example, a crack was confirmed in a part of the plating film 103.

<Evaluation of resin molding>
In the same manner as in Example 1, (1) water absorption of the first and second parts, (2) flexural modulus, (3) hot water test, and (4) thermal shock test (heat shock test) were performed. . The results are shown in Table 1. In the resin molded body 100 of this comparative example, cracks were confirmed in a part of the plating film 103 before the thermal shock test. However, the plating film progressed by the thermal shock test. The evaluation result was “C”.

  In the resin molded body 100 of this comparative example, a plating film can be easily formed only on the first portion 101, and the contrast with and without the plating film was clear. In the second portion 102, no deposition of the plating film was observed. However, in the resin molded body 100 of this comparative example, a crack was confirmed in a part of the plating film 103. This is presumed that since the water absorption rate of the first member was too high, the first part was swollen during plating and adhesion to the plating film could not be secured. From this result, it was found that the water absorption rate of the first part needs to be smaller than 3.2% by weight, and preferably 3.0% by weight or less.

  The resin molding of the present invention has a clear contrast with the presence or absence of a partially formed plating film and is excellent in design. In addition, it has high rigidity, heat resistance, and chemical resistance.For example, it is suitable for automobile interior and exterior parts, building material parts, home appliance parts, etc. because it can provide long-term reliability in harsh environments such as automobile interiors. is there.

100 resin molded body 101 first part 102 second part 103 plating film

104 First thermoplastic resin 105 Block copolymer having hydrophilic segment 106 Metal fine particle 107 Metal particle

Claims (15)

A resin molded body,
A first portion having a plating film formed on the surface;
Having a second portion where no plating film is formed on the surface;
The first part is
A first thermoplastic resin;
A block copolymer having a hydrophilic segment;
Containing fine metal particles,
The second portion includes a second thermoplastic resin,
The water absorption rate of the first part when immersed in water at 23 ° C. for 24 hours is 0.5% by weight to 3.0% by weight, and the water absorption rate of the second part is 2.0% by weight. A resin molded product characterized by the following.   The resin molded body according to claim 1, wherein the first thermoplastic resin contains polyamide.   The bending elastic modulus at normal temperature of a portion having a larger occupied volume in the resin molded body among the first portion and the second portion is 5 GPa or more. Resin molded body.   The resin molding according to any one of claims 1 to 3, wherein the second thermoplastic resin contains polyamide.   The resin molding according to any one of claims 1 to 3, wherein the second thermoplastic resin contains polypropylene.   The resin molded body according to any one of claims 1 to 5, wherein the second part does not contain the metal fine particles.   The resin molded body according to any one of claims 1 to 6, wherein the metal fine particles are palladium.   The resin molded body according to any one of claims 1 to 7, wherein the first part contains 1 to 50 ppm by weight of the metal fine particles.   The resin molded body according to any one of claims 1 to 8, wherein the first portion and the second portion are integrally molded.   The resin molded body according to any one of claims 1 to 9, wherein the plating film contains nickel phosphorus or nickel boron.   The domain of the block copolymer containing the metal fine particles is present in the matrix made of the first thermoplastic resin in the first part. Resin molded body. It is a manufacturing method of the resin fabrication object according to claims 1-11,
Preparing a resin pellet containing the block copolymer and the metal fine particles;
Plasticizing and melting the first thermoplastic resin and the resin pellets into a first molten resin;
Plasticizing and melting the second thermoplastic resin into a second molten resin;
Molding a resin member having a first portion made of the first molten resin and a second portion made of the second molten resin, using the first molten resin and the second molten resin; ,
A method for producing a resin molded body comprising forming the plating film on a surface of a first portion of the resin member. Preparing the resin pellets,
13. The resin according to claim 12, comprising contacting the block copolymer with pressurized carbon dioxide in which the metal fine particles are dissolved or dispersed, and allowing the metal fine particles to permeate the block copolymer. Manufacturing method of a molded object.   The method for producing a resin molded body according to claim 12 or 13, wherein the resin member is molded by two-color molding.   15. The resin molded body according to claim 12, wherein the entire resin member is immersed in an electroless plating solution to form the plating film only on the surface of the first part. Production method.

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