WO2018117160A1 - Method for producing plated molded body, and plated molded body - Google Patents

Abstract

Provided is a method for producing a plated molded body, which forms an electroless plating film on a molded body having high plating reactivity by a low-cost method that places only a little burden on the environment. This method for producing a plated molded body comprises: a process for obtaining a molded body by molding a thermoplastic resin that contains cellulose nanofibers; a process for bringing an electroless plating catalyst liquid that contains a metal salt into contact with the molded body; and a process for forming an electroless plating film on the surface of the molded body by bringing an electroless plating liquid into contact with the molded body, which has been brought into contact with the electroless plating catalyst liquid.

Description

Method for producing plated molded body and plated molded body

The present invention relates to a plated molded body and a method for manufacturing the plated molded body.

Electroless plating is known as a method for forming a metal film at low cost on a molded body. In electroless plating, in order to secure the adhesion strength of the metal film to the molded body, 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. Therefore, an ABS resin (acrylonitrile / butadiene / styrene copolymer synthetic resin) that is eroded by an etching solution has been mainly used for electroless plating. 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 a pretreatment of electroless plating has a problem of high environmental load because hexavalent chromic acid or the like is used.

An electroless plating catalyst is applied to the surface of the roughened molded body, and then electroless plating is performed. As the electroless plating catalyst application to the plastic substrate, two kinds of methods are mainly used. After adsorbing the tin colloid on the substrate (Sensitizer), immersing it in a palladium chloride solution (Activator), reducing and precipitating the palladium chloride with stannous chloride, and the palladium tin colloid as the substrate This is a catalyst / accelerator method in which the catalyst is adsorbed (catalyst) and then reduced with concentrated sulfuric acid (accelerator). The sensitizer / activator method has a problem that the mass productivity is low because the bath life of the tin colloid used in the sensitizer is short. For this reason, the catalyst accelerator method is mainly employed as an industrial electroless plating catalyst application method.

On the other hand, an improved pretreatment method for electroless plating has also been proposed. For example, in Patent Document 1, in order to reduce the number of steps in the plating pretreatment, molding is performed with one solution containing a corrosive agent containing an inorganic acid such as hydrochloric acid, an ionogenic activator such as palladium ion, and an organic acid such as acetic acid. Methods for treating the body have been proposed. According to Patent Document 1, it is not necessary to use hexavalent chromic acid having a high environmental load by performing the pretreatment of the polyamide substrate with the above-mentioned one solution, and a good plating film can be obtained. Patent Document 2 proposes an electroless plating catalyst solution containing a complex of palladium ion and 2-aminoethylpyridine as an alternative to a sensitizer solution containing palladium-tin colloid used in the sensitizer / activator method. . The conventional sensitizer solution contains tin that has a high environmental load, and also has a problem that the palladium-tin colloid easily aggregates. According to Patent Document 2, the proposed electroless plating catalyst solution does not contain tin, which has a high environmental load, and is more stable for a long time compared to conventional sensitizer solutions.

Japanese Patent No. 4109615 JP 2015-48529 A

However, the method proposed in Patent Document 1 mainly uses a molded body made of polyamide. Therefore, there is a possibility that an electroless plating film having high adhesion strength cannot be formed on a molded body made of a thermoplastic resin other than polyamide. Moreover, since the method proposed in Patent Document 2 forms a new palladium complex, the cost of the electroless plating catalyst may increase.

The present invention solves these problems, and provides a method for producing a plated molded body in which an electroless plated film is formed on a molded body having high plating reactivity by a method having a low environmental load and low cost. In addition, a plated molded body having a plating film with high adhesion strength and high heat cycle resistance is provided.

According to the first aspect of the present invention, there is provided a method for producing a plated molded body, in which a molded body is obtained by molding a thermoplastic resin containing cellulose nanofibers, and the molded body contains a metal salt. Contacting an electroplating catalyst solution, and contacting the electroless plating solution with the molded body contacted with the electroless plating catalyst solution to form an electroless plating film on the surface of the molded body. A manufacturing method is provided.

Before the molded body is brought into contact with the electroless plating catalyst solution, the molded body may be subjected to a swelling process or an etching process. The metal salt contained in the electroless plating catalyst solution may be one selected from the group consisting of palladium chloride, silver chloride, copper chloride, and silver nitrate. Further, the thermoplastic resin may include polyamide, polypropylene, or ABS resin.

Molding the molded body may include preparing resin pellets containing the thermoplastic resin and the cellulose nanofibers, and molding the resin pellets to obtain the molded body. In addition, preparing the resin pellets obtains a mixture of a molten resin obtained by plasticizing and melting the thermoplastic resin and a slurry in which the cellulose nanofibers are dispersed in a solvent, and removing the solvent from the mixture And extruding the mixture from which the solvent has been removed to obtain an extrudate, and crushing the extrudate to obtain the resin pellets. Preparing the resin pellets may further include adding water to the mixture of the molten resin and the slurry.

According to the second aspect of the present invention, a plated molded body comprising a thermoplastic resin, a molded body containing cellulose nanofibers, and an electroless plating film formed on the surface of the molded body. A shaped body is provided.

The molded body may be a foamed molded body having foam cells inside. Further, the thermoplastic resin may include polyamide, polypropylene, or ABS resin.

In the present invention, an electroless plating film can be formed on a molded body having high plating reactivity containing cellulose nanofibers by a method with low environmental load and low cost. Moreover, the plating molded object obtained by this invention has a plating film with high adhesive strength, and has high heat cycle tolerance.

FIG. 1 is a flowchart showing a method of manufacturing a plated molded body manufactured in the embodiment. FIG. 2 is a schematic view of a resin pellet manufacturing apparatus used in Example 1. FIG. 3 is a partially enlarged view of the manufacturing apparatus shown in FIG. FIG. 4 is a schematic view of a production apparatus for producing the foam molded article used in Example 3.

Referring to FIG. 1, a method for producing a plated molded body (molded body having a plated film) in the present embodiment will be described.

(1) Molding of molded body First, a thermoplastic resin containing cellulose nanofibers is molded to obtain a molded body (step S1 in FIG. 1). Examples of the thermoplastic resin include polyamide such as nylon, polypropylene, polymethyl methacrylate, polycarbonate, amorphous polyolefin, polyether imide, polyethylene terephthalate, polyether ether ketone, ABS resin, polyphenylene sulfide, polyamide imide, polylactic acid, polycaprolactone. Etc. can be used. Among these, polyamide, polypropylene, and ABS resin are preferable as the thermoplastic resin used in the present embodiment. Polyamide has a relatively high hydrophilicity and is suitable for forming an electroless plating film. Polypropylene is inexpensive, lightweight and excellent in chemical resistance, and is preferable as a plated part for automobiles and the like. On the other hand, polypropylene does not easily penetrate the plating solution, but can be plated by mixing an extractant. ABS resin has been used most frequently as a plated part and has a wide range of applications. Conventional plating on ABS resin requires etching using chromic acid or the like as a plating pretreatment, but as described later, etching using an organic solvent instead of chromic acid is also possible. As these thermoplastic resins, one type of resin may be used alone, or two or more types may be mixed and used.

In this embodiment, the cellulose nanofiber (hereinafter referred to as “CNF” as appropriate) is a material obtained by unraveling fibers of a material (for example, wood pulp) containing plant fibers to a nanosize level. CNF is a fiber with a large aspect ratio having a diameter of 4 to 100 nm and a length of 1 μm or more. In this specification, the cellulose nanocrystal (CNC) which is a needle-like crystal is also included in CNF. By including CNF in the molded body, the present inventors adsorb metal ions that function as an electroless plating catalyst on the surface of the molded body in a subsequent electroless plating catalyst application step (step S2 in FIG. 1). As a result, it has been found that the electroless plating reactivity of the molded body is improved. That is, as a first effect of the present embodiment, CNF acts as an adsorbent for metal ions.

Inclusion of CNF in the molded body brings about the following advantages in addition to the above-described 1) improving the reactivity of electroless plating by adsorbing metal ions. 2) Since CNF is hydrophilic, the catalyst solution and the plating solution easily penetrate into the molded body containing CNF. Then, the plating film grows from the inside of the molded body with the CNF buried in the molded body as a base point, and the fibrous CNF suppresses the peeling of the plating film. Thereby, the adhesion strength of the plating film is improved. 3) CNF has a low specific gravity and a low thermal expansion coefficient and a high elastic modulus. When a molded object contains CNF, the thermal expansion coefficient of a molded object reduces and an elasticity modulus improves. Thereby, also in heat shock tests, such as a heat shock test, the high adhesiveness of a molded object and a plating film is maintained (heat cycle tolerance improvement), and the reliability of a plating molded object increases. In addition, although the same effect is acquired also by including glass fiber etc. in a molded object, since glass fiber has large specific gravity, there exists a possibility of deteriorating the surface property of a plating molded object. On the other hand, since the specific gravity of CNF is small, it is possible to improve both the reliability and surface properties of the plated molded body. 4) Since CNF is a nanofiber with a small diameter, it is hard to affect the external appearance of the surface of the molded object containing this. For this reason, the plating molded object with high designability can be manufactured. 5) CNF has a small anisotropy of filler orientation. For this reason, it is difficult to cause unevenness in the adsorption amount of metal ions on the surface of the molded body. 6) CNF has little adverse effect on the human body.

The specific surface area of the CNF, preferably 70 ~ 300m ² / g, more preferably 70 ~ 250m ² / g, more preferably 100 ~ 200m ² / g. When the specific surface area of CNF is large, the adsorptivity of metal ions and the strength of the molded body are improved. However, when the specific surface area is extremely large, the resin tends to aggregate in the resin. Therefore, the above-mentioned range is preferable for the specific surface area of CNF. When CNF is defibrated to the nano level, it is difficult to measure the fiber diameter and length using X-ray CT or the like, so it is difficult to analyze the dispersion state of CNF in the resin. However, it is preferable to use CNF that has been defibrated to the nano level from the viewpoint of increasing the specific surface area of CNF to some extent within the above range.

The production method of CNF is not particularly limited, and may be produced by any production method, or a commercially available product may be used. Moreover, in order to improve the dispersibility to a thermoplastic resin, the surface modification of CNF may or may not be performed by a known method. The surface modification of CNF has the advantage of improving the mechanical properties of the molded body, such as decreasing the thermal expansion coefficient of the molded body and increasing the elastic modulus, depending on the type of resin in which CNF is dispersed. On the other hand, from the viewpoint of the ability to adsorb metal ions serving as a plating catalyst, the surface modification of CNF is not a particularly necessary treatment. Rather, if CNF aggregation can be suppressed, it is better not to modify the surface of CNF. preferable. When the surface modification of CNF is not performed, there are advantages in that the manufacturing cost is reduced and the manufacturing time is shortened. Moreover, although the surface state of CNF changes by surface modification, there exists a possibility that the adsorption | suction ability of a metal ion may not change or may fall.

CNF is contained in the thermoplastic resin in an amount of, for example, 0.1% to 50% by weight, preferably 0.5% to 20% by weight, and preferably 1% to 10% by weight. More preferred. CNF increases the plating reactivity of the molded body and improves the adhesion strength of the plating film. However, if the ratio to the thermoplastic resin is too high, the moldability may be significantly lowered due to the increase in viscosity. Therefore, the above range is preferable for the ratio of CNF to the thermoplastic resin.

In this embodiment, a block copolymer containing a hydrophilic segment (hereinafter referred to as “block copolymer” as appropriate) may be further mixed with the thermoplastic resin and molded to obtain a molded body. The block copolymer used in the present embodiment has a hydrophilic segment, and further has another segment different from the hydrophilic segment (hereinafter referred to as “other segment” as appropriate). When the molded body contains the block copolymer, the surface of the molded body is hydrophilized, the catalyst solution and the plating solution are easily penetrated into the molded body, and the growth of the plating film is promoted. When a hydrophobic material such as an ABS resin is used as the thermoplastic resin, mixing of the block copolymer is particularly effective.

An anionic segment, a cationic segment, and a nonionic segment can be used as the hydrophilic segment of the block copolymer. Examples of the anionic segment include polystyrene sulfonic acid, the cationic segment includes a quaternary ammonium base-containing acrylate polymer system, and the nonionic segment includes a polyether ester amide system, a polyethylene oxide-epichlorohydrin system, and a polyether ester system. It is done. As the block copolymer used in 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 oxyalkylene groups having 2 to 4 carbon atoms such as oxyethylene group, oxypropylene group, oxytrimethylene group, and oxytetramethylene group, polyether diol, polyether diamine, and their modifications. As well as polyether-containing hydrophilic polymers, with polyethylene oxide being particularly preferred.

In the present embodiment, the other segment of the block copolymer is arbitrary as long as it is more hydrophobic than the hydrophilic segment, but, for example, nylon, polyolefin or the like can be used.

When the block copolymer is mixed with the thermoplastic resin, the block copolymer may be contained in an amount of, for example, 0.5% to 10% by weight and 1% to 5% by weight with respect to the thermoplastic resin. More preferred. The block copolymer promotes the growth of the plating film, but if the content in the molded body is too large, the mechanical strength of the molded body may be lowered. Therefore, the ratio of the block copolymer to the thermoplastic resin is preferably in the above range.

In the present embodiment, the thermoplastic resin may be further mixed with various inorganic fillers such as glass fiber, talc, and carbon fiber and molded to obtain a molded body. When a filler is mixed with a thermoplastic resin, a commercially available resin in which an inorganic filler is mixed in advance, a so-called inorganic filler reinforced resin, may be used as the thermoplastic resin. In addition, if necessary, a general-purpose additive may be added to the thermoplastic resin to form a molded body.

<Production method of resin pellet>
The molding method of a molded object is not specifically limited, A general purpose method can be used. For example, first, resin pellets containing a thermoplastic resin and CNF may be prepared, and the resin pellets may be molded by a general-purpose method to obtain a molded body. By producing a molded body using resin pellets in which CNF is uniformly dispersed in a thermoplastic resin, a good dispersion state of CNF can be maintained even in the molded body. The composition of the resin pellet can be appropriately determined based on the composition of the molded article to be produced.

Resin pellets may be made in-house or commercially available. The manufacturing method of the resin pellet is not particularly limited, and any method can be used. For example, as disclosed in JP 2013-79334 A, a monomer constituting a thermoplastic resin (polyamide) and an aqueous dispersion of CNF (CNF aqueous slurry) are mixed to obtain a polymerization reaction. The obtained resin composition may be taken out and pulverized to produce pellets. Or you may use the commercial item manufactured by the same method. Alternatively, the so-called Kyoto process (for example, New Energy and Industrial Technology Development Organization, News, National Research and Development Corporation, News, which disperses surface-modified cellulose into CNF in a twin-screw extruder while defibrating into CNF. Release, March 23, 2016, “Developing a resin composite material reinforced with high-performance nanofibers and a high-efficiency manufacturing process-A test plant for integrated manufacturing starts operation in Kyoto University”) Also good.

As another method for producing resin pellets, for example, CNF, and if necessary, after extruding a thermoplastic resin containing a block copolymer or the like (hereinafter, appropriately described as “resin pellet material”), The extrudate may be cut to produce resin pellets. CNF and thermoplastic resin may be mixed (dry blended) and then introduced into the plasticizing cylinder of the extruder. Alternatively, the thermoplastic resin is first plasticized and melted in the plasticizing cylinder. Alternatively, CNF may be introduced into the plasticizing cylinder later and mixed with the molten resin. The form of CNF mixed with the thermoplastic resin is not particularly limited, and may be, for example, dry powder CNF or slurry CNF (CNF slurry) dispersed in a solvent such as water.

When a CNF slurry dispersed in water is used for producing resin pellets, a mixture of a molten resin obtained by plasticizing and melting a thermoplastic resin and a CNF slurry is obtained in a plasticizing cylinder. At this time, it is preferable that the CNF slurry is sufficiently dispersed in the molten resin while maintaining the liquid phase. For this reason, it is preferable to maintain the pressure in the plasticizing cylinder of the extrusion molding machine at a high pressure at which the solvent of the CNF slurry can maintain the liquid body even in a high temperature state where the thermoplastic resin melts. When the temperature of the liquid becomes high, the density rapidly decreases and the function as a solvent for dissolving or dispersing the solute is lost. However, by increasing the pressure, the decrease in the solvent density of the solvent can be prevented, and the precipitation and aggregation of CNF can be suppressed. . Therefore, it is preferable that the plasticizing cylinder of the extruder used for producing the resin pellets has a high-pressure kneading zone in which the molten resin and the CNF slurry can be mixed at high temperature and high pressure. The temperature and pressure of the high-pressure kneading zone for mixing the molten resin and the CNF slurry can be determined according to the type of the thermoplastic resin and the type of the solvent of the CNF slurry, and are, for example, 150 ° C. to 280 ° C., 3 MPa to 20 MPa, Preferably, they are 180 ° C. to 230 ° C. and 7 MPa to 15 MPa.

In the high-pressure kneading zone, it is preferable to further mix water with the mixture of the molten resin and the CNF slurry. The introduced water prevents the CNF slurry from drying in the high-pressure kneading zone, and further suppresses the aggregation of CNF in the molten resin. Since water is introduced into a mixture of a molten resin and a CNF slurry in a high temperature and pressure state, it is preferably in a pressure state.

After sufficiently mixing the molten resin and the CNF slurry, the mixture of the molten resin and the slurry is preferably decompressed before being extruded to remove the solvent and water of the slurry from the mixture. Therefore, it is preferable that the plasticizing cylinder of the extruder used for the production of the resin pellets has a reduced pressure zone that lowers the resin internal pressure of the molten resin and removes the solvent of the slurry from the molten resin. The removed solvent is discharged out of the plasticizing cylinder from a vent provided in the decompression zone. Further, when the molten resin containing a large amount of solvent is rapidly decompressed, the resin expands greatly, and so-called vent-up is likely to occur. In order to prevent sudden pressure reduction of the molten resin and suppress vent-up, it is preferable to provide a gradual pressure reducing section for gradually evacuating the mixture of the molten resin and the slurry upstream of the vent in the pressure reducing zone.

A mixture of molten resin and CNF slurry is extruded into a string shape, cooled, and then cut using a general-purpose cutting device such as a strand cutting device to obtain resin pellets. Extrusion molding, cooling and cutting are preferably performed continuously from the viewpoint of productivity of resin pellets.

<Molding method of molded body>
The molding method of the molded body is not particularly limited. The formed resin pellets may be molded by general-purpose molding such as injection molding or extrusion molding to obtain a molded body having a desired shape. Further, the produced resin pellets may be foam-molded to obtain a foam-molded body having foam cells inside. In general, the foam molded article tends to have a reduced mechanical strength. However, the foam molded article contains CNF, so that the reduction in mechanical strength due to foaming can be partially offset by the reinforcing effect of CNF. Foam molding is broadly divided into a chemical foaming method using a chemical foaming agent and a physical foaming method using a physical foaming agent, and the physical foaming method is preferable because the foaming agent is inexpensive and does not have an adverse effect of the foaming agent residue. . In particular, foam molding using carbon dioxide or nitrogen as a physical foaming agent is preferable because the foamed cells become fine due to the foaming nucleating agent effect and the thickening effect of CNF. The pressure of the physical foaming agent such as carbon dioxide or nitrogen is preferably not higher than the supercritical pressure. By setting the pressure to a supercritical pressure or lower, it is possible to suppress the appearance defect of the molded body called a swirl mark that occurs when the molded body is injection molded.

As mentioned above, although the resin pellet containing a thermoplastic resin and CNF was prepared and the resin pellet was shape | molded by the general purpose method and demonstrated, the method of obtaining a molded object was demonstrated, but this embodiment is not limited to this. For example, without using resin pellets containing CNF, thermoplastic resin is mixed with CNF and, if necessary, inorganic filler, etc., and then molded by general-purpose injection molding, extrusion molding, etc., directly to the desired A shaped molded body may be obtained.

(2) Pre-plating treatment In the present embodiment, as the pre-plating treatment, it is preferable that the molded body is first subjected to etching treatment or swelling treatment. Then, after that, an electroless plating catalyst solution containing a metal salt is brought into contact with the formed body (step S2 in FIG. 1). Thereby, the metal ion derived from the metal salt which functions as an electroless plating catalyst can be imparted to the surface of the molded body.

<Etching treatment or swelling treatment of molded article>
Before bringing the catalyst solution into contact with the molded body, it is preferable to subject the molded body to an etching treatment or a swelling treatment. When the molded body is etched, the amount of CNF exposed on the outermost surface of the molded body increases, and metal ions that function as an electroless plating catalyst are more easily adsorbed on the surface of the molded body. In addition, when the molded body is subjected to swelling treatment, metal ions easily penetrate into the molded body together with the catalyst solution, and are adsorbed by CNF inside the molded body (near the surface). Thus, when the molded body is etched or swelled, metal ions adsorbed on the molded body are increased, and the electroless plating reactivity of the molded body is further improved.

The etching treatment method and the swelling treatment method of the molded body can be appropriately selected depending on the type of thermoplastic resin used in the molded body. However, it is preferable not to use a reagent with a large environmental load such as chromic acid.

For example, as a thermoplastic resin, a molded body using a copolymer or a polymer alloy containing a rubber component such as an ABS resin has a surface tension of 36 mN / m or less and a solubility parameter (SP value) of 12. You may etch the surface of a molded object by making the etching liquid containing the solvent which is the following contact a molded object. If the surface tension is 36 mN / m or less, the surface of the molded body can be sufficiently wetted. If the SP value is 12 or less, the SP value of the etching solution and the SP value of the butadiene component of the ABS resin Is a close value. By bringing an etching solution containing such a solvent into contact, micropores can be formed on the surface of the molded body. In addition, the value of the surface tension of the solvent in this specification means the value of the surface tension at room temperature. Specific examples of the solvent include ethylene glycol monobutyl ether, diethylene glycol monohexyl ether, dipropylene glycol monomethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, and triethylene glycol monobutyl ether glycol ether. Can be mentioned. Of these, dipropylene glycol monomethyl ether is preferred.

For molded products using chemically stable materials such as polypropylene, etc. as thermoplastic resins, extract materials that can be extracted with acid or water are included in the molded product in advance, and acid or water is used as the etching solution. By contacting the body, the extracted material may be extracted to etch the surface of the molded body. As the extraction material, inorganic particles such as calcium hypophosphite, calcium carbonate, magnesium carbonate, magnesium sulfate, and magnesium oxide, high melting point organic compounds such as pentaerythritol, and the like can be used. Examples of the acid include hydrochloric acid, sulfuric acid, and nitric acid, and can be appropriately selected depending on the extraction material.

In addition, for a molded body using an aliphatic polyamide such as polyamide 6 (PA6) or polyamide 66 (PA66) as the thermoplastic resin, after contacting the acid, hot water (hot water) is contacted. The molded body surface may be swollen. Examples of the acid include hydrochloric acid. The temperature of the hot water is preferably a temperature equal to or higher than the glass transition point of the aliphatic polyamide in the molded body in order to enhance the swelling effect of the molded body, for example, 50 to 90 ° C., preferably 60 to 75 ° C.

<Applying electroless plating catalyst>
After the molded body is etched or swelled, the molded body is contacted with an electroless plating catalyst solution containing a metal salt (step S2 in FIG. 1). Thereby, the metal ion derived from the metal salt which functions as an electroless plating catalyst can be imparted to the surface of the molded body.

The metal salt contained in the electroless plating catalyst solution is a metal salt having electroless plating catalytic ability, and any metal salt can be used as long as it dissolves in water and generates metal ions. For example, salts such as Pd, Pt, Cu, Ni, and Ag can be mentioned, and Pd, Ag, and Cu are particularly preferable. As metal salts, chlorides, sulfides, iodides, fluorides, bromides, etc. of these metals can be used, but chlorides are preferred from the viewpoint of stability, versatility, and cost, and copper chloride, silver chloride Palladium chloride is particularly preferred.

The concentration of the metal salt in the electroless plating catalyst solution can be adjusted as appropriate based on conditions such as the temperature of the electroless plating catalyst solution and the contact time between the electroless plating catalyst solution and the molded article. 500 mg / L, preferably 1 to 250 mg / L, more preferably 5 to 150 mg / L. If the concentration of the metal salt is lower than the above range, the amount of metal ions adsorbed on the molded product may be uneven, and defects in the plating film may occur. Further, when the concentration of the metal salt exceeds the above range, the amount of metal ions adsorbed on the surface of the molded body increases, the plating reaction on the outermost surface of the molded body becomes dominant, and the adhesion strength of the plating film may be reduced. There is.

The solvent of the electroless plating catalyst solution for dissolving the metal salt is not particularly limited and can be selected according to the type of the metal salt, for example, water; ethanol, propanol, isopropanol, butanol, isobutanol, acetone, ethyl methyl ketone. Organic solvents such as: mixed solvents thereof. Furthermore, in order to increase the solubility of the metal salt, hydrochloric acid, nitric acid, ammonia, sodium hydroxide, or the like may be added to adjust the pH of the liquid. As the electroless plating catalyst solution of this embodiment, an aqueous hydrochloric acid solution of palladium chloride is preferable. When the electroless plating catalyst solution contains hydrochloric acid, the concentration of hydrochloric acid in the electroless plating catalyst solution is, for example, 0.1 to 12N, preferably 0.1 to 5N, and more preferably 1.0 to 4.0N. preferable. In particular, since palladium chloride may be precipitated when the concentration of hydrochloric acid is lowered, the state of palladium ions can be stably maintained by setting the hydrochloric acid concentration to 0.1 N or more. On the other hand, if the concentration of hydrochloric acid exceeds 12N, the appearance characteristics of the plating film and the mechanical strength of the molded body may be affected by dissolution of the molded body.

The electroless plating catalyst solution may be composed of only a metal salt and a solvent, or may contain a general-purpose additive as necessary. The electroless plating catalyst solution may contain a surfactant, for example. By containing the surfactant, the surface tension of the electroless plating catalyst solution is reduced, the wettability to the surface of the molded body is improved, and the metal salt is easily adsorbed on the surface of the molded body. As the surfactant, a general-purpose surfactant such as an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant can be used.

The electroless plating catalyst solution may be prepared by mixing a metal salt, a solvent, and a general-purpose additive as necessary, or a commercially available product may be used. For example, when an aqueous hydrochloric acid solution of palladium chloride is used as the electroless plating catalyst solution, it can be prepared by adding palladium chloride to hydrochloric acid (aqueous hydrochloric acid solution) and stirring until the palladium chloride is dissolved. Moreover, as a commercial item, the catalyzing processing agent (activator) used for a sensitizer activator method can be used, for example. In the usual sensitizer / activator method, a sensitizer treatment using a sensitivity imparting agent (sensitizer) containing Sn ²⁺ is required before the activator treatment using a catalytic treatment agent (activator) containing Pd ^2+. However, the sensitizer processing is not necessary in this embodiment. For this reason, the electroless plating catalyst application method of the present embodiment can reduce the manufacturing cost and improve the throughput as compared with the sensitizer / activator method.

The method of bringing the electroless plating catalyst solution 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 the electroless plating catalyst solution, or only a part of the molded body may be brought into contact with the electroless plating catalyst solution.

The time for bringing the electroless plating catalyst solution into contact with the molded body is preferably, for example, 5 seconds to 15 minutes. If it is less than 5 seconds, there is a possibility that the amount of the metal salt adsorbed on the molded body may be uneven. Moreover, when it exceeds 15 minutes, there exists a possibility that the molded object may deteriorate with the electroless-plating catalyst liquid which osmose | permeated the molded object.

Further, the temperature of the electroless plating catalyst solution brought into contact with the molded body can be appropriately determined according to the kind of the thermoplastic resin, and is, for example, 10 ° C. to 50 ° C. If the temperature is less than 10 ° C., the amount of metal ions adsorbed on the surface of the molded article may be uneven. On the other hand, if the temperature of the electroless plating catalyst solution exceeds 50 ° C., the amount of metal ions adsorbed on the surface of the molded body increases, and the plating reaction on the outermost surface of the molded body may become dominant. Further, when the electroless plating catalyst solution contains hydrochloric acid, it may be difficult to stabilize the hydrochloric acid concentration due to generation of gas from hydrochloric acid or evaporation of water.

In this embodiment, the metal ion derived from the metal salt is adsorbed to the compact by bringing the electroless plating catalyst solution into contact with the compact. The metal ions function as an electroless plating catalyst in a subsequent electroless plating process (step S3 in FIG. 1). This mechanism is presumed as follows.

Generally, metal ions such as palladium that serve as an electroless plating catalyst are difficult to be adsorbed to a molded body as they are. Therefore, in the sensitizer activator method and catalyst accelerator method, which are general-purpose electroless plating catalyst application methods, first, the surface of the molded body is roughened, and further, palladium ions are reduced to reduce the oxidation number 0 (zero) metal. It is made to adsorb | suck to a molded object as palladium. Therefore, conventionally, even when a liquid containing metal ions such as palladium that is not in a metallic state is brought into contact with the molded body, the metal ions are hardly adsorbed on the surface of the molded body. Since the catalyst activity was not exhibited in the state, it was difficult to use as an electroless plating catalyst.

In this embodiment, since the molded body contains CNF, metal ions are easily adsorbed on the surface of the molded body. The reason why CNF has such characteristics is not clear, but it is speculated that it is due to having a high specific surface area. Furthermore, in this embodiment, the metal ions adsorbed on the molded body function as an electroless plating catalyst in an electroless plating step (step S3 in FIG. 1) in a subsequent step without using a reduction step. This is because the metal ions adsorbed on the compact are reduced by a reducing agent such as sodium hypophosphite, dimethylamine borane and formalin contained in the electroless plating solution in the electroless plating process, It is estimated that

Thus, in this embodiment, an inexpensive metal salt solution can be used as the electroless plating catalyst solution, and the reduction treatment of the electroless plating catalyst (metal ions) can be omitted. Thereby, manufacturing cost can be reduced and throughput can be improved.

(3) Electroless plating Next, an electroless plating solution is brought into contact with the formed body that has been subjected to the plating pretreatment to form a plated film (step S3 in FIG. 1). Is obtained. As the electroless plating solution, any general-purpose electroless plating solution can be used according to the purpose, for example, an electroless nickel phosphorus plating solution, an electroless copper plating solution, an electroless tin plating solution, Among these, an electroless nickel phosphorus plating solution is preferable from the viewpoint that the catalyst activity is high and the solution is stable.

The electroless plating temperature and the electroless plating time can be appropriately set according to the type of thermoplastic resin, the type of electroless plating solution, and the like. The electroless plating temperature (temperature of the electroless plating solution) is, for example, 50 ° C. to 80 ° C., and preferably 50 ° C. to 70 ° C. Further, the electroless plating time (the time for which the electroless plating solution is brought into contact with the formed body) is, for example, 30 seconds to 30 minutes.

A plurality of different types of electroless plating films may be formed on the molded body on which the electroless plating film is formed for the purpose of improving the use and design of the molded body, or by electroplating. May be formed. 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.

Since the plated molded body obtained in the present embodiment contains CNF in the molded body, it has a plating film with high adhesion strength and has high heat cycle resistance. Moreover, since the molded object containing CNF has high water absorption in the state in which a plating film is not formed, swelling by water absorption etc. becomes a problem depending on a use. The plated molded body of the present embodiment can be used for various purposes because the plated film formed on the surface of the molded body can suppress water absorption of the molded body.

Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited by the following examples and comparative examples.

[Example 1]
In this example, first, a resin pellet containing a thermoplastic resin, CNF, and a block copolymer was manufactured, and the manufactured resin pellet was molded to obtain a molded body. Then, the obtained molded body was subjected to etching, electroless plating catalyst application, and electroless plating in this order to obtain a plated component of this example.

As the thermoplastic resin, ABS resin (Toyolac 125-X82, manufactured by Toray Industries, Inc.) is used. CNF water slurry) was used. As the block copolymer, a block copolymer of nylon and polyethylene oxide (manufactured by Sanyo Chemical Industries, Pelestat NC6321) was used.

(1) Resin pellet manufacturing apparatus First, the manufacturing apparatus 1000 used for manufacture of the resin pellet in a present Example is demonstrated. As shown in FIG. 2, the manufacturing apparatus 1000 includes an extruder 200 having a plasticizing cylinder 210, a supply mechanism 100 that supplies water (liquid A) to the plasticizing cylinder 210, and a control device (not shown). . The control device controls the operations of the extrusion molding machine 200 and the supply mechanism 100.

(A) Extruder molding machine In this embodiment, even at a high temperature at which the thermoplastic resin is plasticized and melted, the high viscosity slurry in which CNF is dispersed and the water added to the molten resin can be kneaded into the molten resin in a liquid state. A molding machine 200 is used. An extrusion molding machine 200 shown in FIG. 2 drives a plasticizing cylinder 210, a die 29 provided at the tip of the plasticizing cylinder 210, a screw 20 disposed rotatably in the plasticizing cylinder 210, and the screw 20. A screw drive mechanism (not shown), an upstream seal mechanism S1 and a downstream seal mechanism S2 disposed in the plasticizing cylinder 210, and a vacuum pump P connected to the plasticizing cylinder 210. In the present embodiment, in the plasticizing cylinder 210, the plasticized and melted molten resin flows from the right hand to the left hand in FIG. Therefore, in the plasticizing cylinder 210 of this embodiment, the right hand in FIG. 2 is defined as “upstream” or “rear”, and the left hand is defined as “downstream” or “front”. Note that the extruder 200 of the present embodiment, like the configuration of a conventionally known extruder, rotates the screw 20 counterclockwise when viewed from the rear side of the plasticizing cylinder 210. It is configured to perform forward rotation sent forward (nozzle side) and reverse rotation when rotated clockwise.

On the upper side surface of the plasticizing cylinder 210, in order from the upstream side, a resin supply port 201 for supplying thermoplastic resin to the plasticizing cylinder 210, an introduction port 202 for introducing liquid A into the plasticizing cylinder 210, A vent 203 for exhausting the solvent and liquid A of the CNF slurry gasified from the plasticizing cylinder 210 is formed. The resin supply port 201 is provided with a resin supply hopper 211 via a feeder screw 121, and the introduction port 202 is provided with an introduction valve 212 incorporating a backflow prevention valve. A vacuum pump P is connected via the container 213. The introduction valve 212 is connected to the supply mechanism 100 provided outside the extrusion molding machine 200. A band heater (not shown) is disposed on the outer wall surface of the plasticizing cylinder 210, whereby the plasticizing cylinder 210 is heated to plasticize the thermoplastic resin.

In the extrusion molding machine 200 having such a structure, the thermoplastic resin and the CNF slurry are supplied from the resin supply port 201 into the plasticizing cylinder 210, and the thermoplastic resin is plasticized by the band heater to become a molten resin. It is sent downstream by rotating forward. The molten resin sent to the vicinity of the inlet 202 is contact-kneaded with the introduced liquid A under high pressure. Next, by reducing the internal pressure of the molten resin that has been kneaded with the liquid A, the solvent of the gasified slurry and the liquid A are separated from the molten resin and are exhausted from the vent 203. Then, the molten resin sent further forward is pushed out from the die 29.

As a result, in the plasticizing cylinder 210, in order from the upstream side, the plasticizing zone 21 that plasticizes the thermoplastic resin into the molten resin, and the molten resin and the liquid A introduced from the inlet 202 are contact-kneaded under high pressure. By reducing the internal pressure of the high-pressure kneading zone 22 and the molten resin, a reduced-pressure zone 23 for exhausting the solvent and liquid A of the slurry separated from the molten resin from the vent 203 is formed. Further, a recompression zone 24 is provided downstream of the decompression zone 23.

The following describes each zone further. The plasticizing zone 21 is provided with a feed portion 21A and a compression portion 21B from the upstream side. The feed portion 21A is provided with a resin supply port 201 through which a resin pellet material is supplied, and gives residual heat to the resin pellet material supplied therefrom. In the compression part 21B, the resin pellet material to which the residual heat is applied is plasticized and melted. The screw 20 located in the compression part 21B has a structure in which the screw flight depth becomes shallower as it goes downstream. Due to the structure of the screw 20, in the compression part 21B, the molten resin is pressurized as it flows downstream.

An upstream seal mechanism S1 and a downstream seal mechanism S2 are disposed on the upstream side and the downstream side of the high-pressure kneading zone 22, respectively. As the upstream seal mechanism S1, any seal mechanism can be used as long as the backflow of the resin to the upstream side can be suppressed. In this embodiment, a seal ring used for conventional foam molding or the like is employed. The downstream seal mechanism S2 can cause the molten resin to flow to the downstream decompression zone 23 in the upstream high pressure kneading zone 22 with the pressure of the molten resin adjusted to be substantially constant. The detailed structure and function of the downstream side seal mechanism S2 will be described later.

In the decompression zone 23, a slow decompression part 23A and a starvation decompression part 23B are provided from the upstream side. As for the screw 20 located in the slow pressure reduction part 23A, the part with a shallow screw flight depth and a deep part are arrange | positioned alternately, and in the starvation pressure reduction part 23B continuing downstream of the slow pressure reduction part 23A, the screw 20 located there The depth of screw flight is deep. Due to the shape of the screw 20 of the gradual decompression unit 23A and the starvation decompression unit 23B, the pressure of the molten resin flowing from the gradual decompression unit 23A to the starvation decompression unit 23B gradually decreases in the gradual decompression unit 23A. Thereby, the sudden pressure reduction of molten resin can be prevented and the vent up from the vent 203 provided in the starvation pressure reduction part 23B can be suppressed. Moreover, in the starvation decompression part 23B where the depth of a screw flight is deep, the starvation state of molten resin is accelerated | stimulated and this also suppresses vent up. Here, the “starvation state” means a state in which the molten resin is not filled in the starvation decompression portion 23B and is not full.

(B) Liquid A Supply Mechanism Next, the liquid A supply mechanism 100 shown in FIG. 2 will be described. The supply mechanism 100 is connected to the introduction valve 212 of the extrusion molding machine 200 and supplies the liquid A to the molding machine 200. The supply mechanism 100 includes a storage container (liquid phase tank) 10 for the liquid A, a double plunger pump 11 that can suck the liquid A from the storage container 10 and then pressurize the liquid A to a predetermined pressure. The back pressure valve 12 adjusts the pressure of the liquid A sent from the double plunger pump 11 before being supplied to the molding machine 200. Further, pressure gauges 13 and 14 are provided on the upstream side (double plunger pump 11 side) and the downstream side (extrusion machine 200 side) of the back pressure valve 12, respectively. The pressure gauge 13 indicates the pressure of the solution A upstream from the back pressure valve 12 (pressure on the double plunger pump 11 side, primary pressure) adjusted by the back pressure valve 12, and the pressure gauge 14 is adjusted by the back pressure valve 12. The pressure of the downstream solution A (pressure on the molding machine 200 side, secondary pressure) is shown.

(C) Downstream side sealing mechanism The downstream side sealing mechanism S2 provided in the extrusion molding machine 200 will be described. The downstream seal mechanism S2 is provided in a boundary region between the high-pressure kneading zone 22 and the decompression zone 23 (gradual decompression unit 23A). The downstream-side seal mechanism S2 is a pressure holding mechanism that allows the molten resin to flow from the high-pressure kneading zone 22 to the decompression zone 23 in a state where the pressure of the molten resin in the high-pressure kneading zone 22 is adjusted to be substantially constant. In this embodiment, since the liquid (solvent of CNF slurry and liquid A) is mixed with the molten resin, the viscosity of the molten resin is reduced. In order to increase the pressure of the molten resin whose viscosity has been lowered in this way, a mechanical seal mechanism as described below is effective. On the other hand, for example, it is considered difficult to control the pressure of the molten resin whose viscosity has been reduced by a technique such as controlling the pressure of the molten resin by designing the shape of the screw flight.

As shown in FIG. 3, the screw 20 has a pressure holding portion 20 </ b> A in which a screw internal flow path 30 in which a molten resin can flow is formed in the boundary region between the high pressure kneading zone 22 and the decompression zone 23. The downstream seal mechanism S2 includes the pressure holding portion 20A, the half seal ring 31 provided on the outer periphery of the pressure holding portion 20A, and the flow of the molten resin that is provided inside the screw 20 and flows through the flow passage 30 in the screw. It is mainly composed of a poppet valve 33 that serves as a resistor and a disc spring 34 that is provided inside the screw 20 and biases the poppet valve 33 upstream.

The in-screw flow path 30 communicates the high pressure kneading zone 22 and the decompression zone 23. On the other hand, the half seal ring 31 prevents the molten resin from flowing from the high-pressure kneading zone 22 to the decompression zone 23 through the outside of the pressure holding unit 20A (screw 20). Therefore, in the downstream seal mechanism S2, the molten resin tends to flow from the high-pressure kneading zone 22 to the pressure-reducing zone 23 through the screw flow path 30 formed in the pressure holding portion 20A.

At this time, if the pressure of the molten resin (pressure in the high-pressure kneading zone 22) is less than a predetermined pressure, the in-screw flow path 30 is blocked by the povet valve 33 and the molten resin cannot flow to the decompression zone 23. Then, when the screw 20 rotates in the forward direction and the molten resin continues to flow from the plasticizing zone 21 to the high-pressure kneading zone 22 while the in-screw flow path 30 is blocked by the povet valve 33, the pressure in the high-pressure kneading zone 22 is increased. Rises. When the pressure in the high-pressure kneading zone 22 becomes equal to or higher than a predetermined pressure, the molten resin pressurizes the poppet valve 33 in the downstream direction (left direction in FIG. 3) with a pressure equal to or higher than the spring force of the disc spring 34. 30 is opened. As a result, the molten resin can flow from the high-pressure kneading zone 22 to the decompression zone 23.

The downstream side seal mechanism S2 opens the in-screw flow path 30 only when the high-pressure kneading zone 22 reaches a certain pressure, and causes the molten resin to flow from the high-pressure kneading zone 22 in the decompression zone 23. When the high-pressure kneading zone 22 becomes less than a certain pressure, the screw flow path 30 is again blocked by the povet valve 33. Thus, the downstream seal mechanism S2 can maintain the pressure of the molten resin in the high-pressure kneading zone 22 at a high pressure with little pressure fluctuation. As a result, in the high-pressure kneading zone 22, the CNF slurry is sufficiently kneaded and dispersed in the molten resin while maintaining its liquid phase. In this embodiment, the downstream side sealing mechanism S2 is designed so that the high-pressure kneading zone 22 can be maintained at 8 to 10 MPa.

(2) Manufacture of resin pellets Using the manufacturing apparatus 1000 shown in FIG. 2 described above, resin pellets containing a thermoplastic resin, CNF, and a block copolymer were manufactured.

Water (liquid A) was stored in the storage container 10. Then, the liquid A was sucked, pressurized and fed by the double plunger pump 11, and the system up to the introduction valve 212 was pressurized. The primary pressure (liquid A pressure upstream of the back pressure valve 12) is set to 12 MPa by the back pressure valve 12, whereby the secondary pressure (liquid A pressure downstream of the back pressure valve 12) is in the range of 8 to 11 MPa. Adjusted.

In the extrusion molding machine 200, the feed section 21A is 220 ° C., the compression section 21B is 240 ° C., the high pressure kneading zone 22 is 190 ° C., the decompression zone 23 is 220 ° C., and the recompression zone 24 is 220 ° C. by a band heater (not shown). Adjusted. In the high-pressure kneading zone 22, the liquid A is introduced, and the viscosity of the molten resin rapidly decreases. In order to maintain the resin density and the internal pressure of the molten resin at a low temperature, the high-pressure kneading zone 22 was set at a lower temperature than the other zones.

First, ABS resin, block copolymer, and CNF slurry (CNF concentration: 10% by weight) are mixed at a ratio of 100 parts by weight, 3 parts by weight, and 40 parts by weight (CNF: 4 parts by weight), and then water ( The solvent of the CNF slurry was partially dried. Thereafter, the mixture (resin pellet material) was supplied to the extrusion molding machine 200 from the resin supply hopper 211. The resin pellet material was supplied to the extrusion molding machine 200 while the supply amount was suppressed by the feeder screw 121. By suppressing the supply amount, in the feed portion 21A, the resin pellet material was maintained in an unfilled state (starved state).

While the screw 20 was rotated in the forward direction, preheating was applied at the feed portion 21A, and the thermoplastic resin and the block copolymer were plasticized and melted at the compression portion 21B. Further, by rotating the screw 20 forward, the molten resin containing the CNF slurry was caused to flow from the plasticizing zone 21 to the high-pressure kneading zone 22.

Next, the introduction valve 212 was opened, and liquid A (water) was introduced into the high-pressure kneading zone 22 at an introduction pressure of 8 to 11 MPa (about 10 MPa). The amount of liquid A introduced was adjusted so that liquid A was about 10% by weight with respect to the resin pellet material.

The pressure in the high-pressure kneading zone 22 is adjusted to a predetermined pressure by the downstream seal mechanism S2, and is maintained in the range of 8 to 10 MPa by a pressure sensor (not shown) provided at a position facing the inlet port 202. I confirmed. In the high-pressure kneading zone adjusted to 190 ° C., the pressure for stably maintaining the liquid phase (water) is about 3 to 5 MPa. Therefore, in the high-pressure kneading zone adjusted to 8 to 10 MPa, the CNF slurry could be mixed with the molten resin while maintaining its liquid phase. Furthermore, CNF aggregation was suppressed by mixing liquid A (water) with the molten resin.

By further rotating the screw 20 forward, the molten resin is allowed to pass from the high-pressure kneading zone 22 through the downstream-side seal mechanism S2 while the high-pressure kneading zone 22 is maintained at a predetermined pressure (8 to 10 MPa). To 23. In the depressurization zone 23, the molten resin is gradually depressurized while flowing from the slow depressurization unit 23A to the starvation depressurization unit 23B, and the solvent (water) and liquid A (water) of the slurry contained in the molten resin are gasified in the starvation depressurization unit 23B. Separated. Gasified water (water vapor) is sucked by the vacuum pump P, discharged from the vent 203 through the vent container 213 to the outside of the plasticizing cylinder 210, and recovered in a recovery container (not shown) connected to the vacuum pump P. It was done.

By further rotating the screw 20, the molten resin is further flowed to the downstream recompression zone 24, and then extruded from a die 29 provided at the tip of the plasticizing cylinder 210 to obtain a string-like molded body. It was. The obtained string-like extruded product was pelletized with a pelletizer (not shown) to obtain resin pellets.

(3) Molding of molded body Next, the obtained resin pellets were injection molded using a general-purpose injection molding machine to obtain a flat molded body of 60 mm x 80 mm x 2 mm. The resin temperature was 230 ° C. and the mold temperature was 70 ° C. Black spots were observed on the surface of the obtained molded body. From this observation result, it is presumed that at least a part of CNF in the molded body is aggregated.

(4) Etching Next, the obtained molded body was immersed in dipropylene glycol monomethyl ether (DPGM) at 40 ° C. for 10 minutes, and then washed with water. Micropores were formed on the surface of the molded body. This is presumably because the butanediene component of the ABS resin contained in the molded body was eluted.

(5) Application of electroless plating catalyst First, 2.0 N hydrochloric acid (aqueous hydrochloric acid solution) containing 50 mg / L palladium chloride was prepared as an electroless plating catalyst solution. The electroless plating catalyst solution was adjusted to 30 ° C., and the compact was immersed for 5 minutes. Thereafter, the molded body was taken out from the electroless plating catalyst solution and washed with water.

(6) Electroless plating An electroless nickel phosphorus plating solution (Okuno Pharmaceutical Co., Ltd., Top Nicolon HMB) in which 0.2% by weight of a surfactant (sodium lauryl sulfate) is dissolved is adjusted to 70 ° C. It was immersed for 1 minute (electroless plating time 10 minutes) to form an electroless nickel phosphorus plating film having a thickness of 1 μm. The electroless plating film was formed on the entire surface of the molded body. Next, the molded body on which the electroless nickel phosphorous film is formed is immersed in a replacement copper plating solution (ANC Acti, manufactured by Okuno Pharmaceuticals Industries Co., Ltd.) for 1 minute at a room temperature, and further, a film thickness of 40 μm is obtained by a general electrolytic copper plating method A copper plating film was formed to obtain a plated molded body of this example.

The adhesion strength of the plating film of the obtained plated molded body was measured using a tensile tester. The adhesion strength of the plating film was 8 N / cm. This result was a value close to 10 N / cm, which is the target value of the adhesion strength of the plating film formed on the molded body.

[Comparative Example 1]
In this comparative example, an ABS resin and a block copolymer drive-driven are injection-molded, and the obtained molded body is etched, electroless-plated catalyst applied, and electroless by the same method as in Example 1. Plating was performed in this order to obtain a plated part. The same ABS resin and block copolymer as in Example 1 were used in the same ratio. That is, in this comparative example, a molded body having the same composition as that of Example 1 was formed except that CNF was not contained in the molded body, and a plated part was manufactured by the same method as in Example 1.

In this comparative example, the electroless plating film was formed only about 60% to 80% of the surface of the molded body. Further, the adhesion strength of the plating film was measured by the same method as in Example 1. As a result, the adhesion strength of the plating film was 3 N / cm.

From the comparison between Example 1 and Comparative Example 1, it was confirmed that the plating reactivity and the adhesion strength of the plating film were improved by containing CNF in the molded body. It was also found that the plating reactivity and the adhesion strength of the plating film were improved even when CNF was somewhat aggregated in the molded body as in the plated molded body of Example 1.

[Example 2]
In this example, resin pellets (manufactured by Unitika) containing CNF were molded, and an electroless plating catalyst was applied to the obtained molded body and electroless plating was performed in this order to obtain a plated part. In this example, unlike Example 1, no block copolymer was used, and the molded product was not etched.

The CNF-containing resin pellets used in this example are resin pellets produced by dispersing CNF in the monomer polymerization reaction process of polyamide 6 (PA6) by the method disclosed in JP 2013-79334 A. Contains about 2% by weight of CNF. PA6, which is a thermoplastic resin, can disperse CNF that is not surface-modified, and CNF contained in the resin pellets of this example is not surface-modified.

(1) Molding of molded body CNF-containing resin pellets were injection molded using a general-purpose injection molding machine to obtain a flat molded body of 60 mm x 80 mm x 2 mm. The resin temperature was 270 ° C. and the mold temperature was 100 ° C. The surface of the obtained molded body was smooth, and the CNF float was hardly noticeable.

(2) Application of electroless plating catalyst and electroless plating In this example, the electroless plating catalyst was prepared in the same manner as in Example 1 except that the electroless plating time was 5 minutes shorter than that of Example 1. Application, electroless plating, displacement copper plating and electrolytic copper plating were performed to obtain a plated molded body. The electroless plating film was formed on the entire surface of the molded body.

The adhesion strength of the plating film was measured by the same method as in Example 1. As a result, the adhesion strength of the plating film was 15 N / cm. This result was a high value significantly exceeding 10 N / cm, which is the target value of the adhesion strength of the plating film formed on the molded body.

Further, a heat shock test was conducted by alternately repeating 100 times (100 cycles) holding the molded body at a high temperature of 90 ° C. for 30 minutes and holding at a low temperature of −35 ° C. for 30 minutes. As a result of the heat shock test, the plating film did not swell or crack.

[Comparative Example 2]
In this comparative example, general-purpose unreinforced PA6 pellets (manufactured by Unitika, Unitika Nylon A1030BRF-BA) that do not disperse CNF were molded, and an electroless plating catalyst was applied to the resulting molded body in the same manner as in Example 2. , And electroless plating were performed in this order to obtain a plated part. That is, in this comparative example, a plated part was produced by the same method as in Example 2 using a molded body having the same composition as in Example 2 except that the molded body did not contain CNF.

In this comparative example, the electroless plating film was not formed on the entire surface of the molded body, and a portion where the plating film was not molded partially occurred at the end of the molded body. Further, the adhesion strength of the plating film was measured by the same method as in Example 1. As a result, the adhesion strength of the plating film was 7 N / cm. Further, a heat shock test was performed in the same manner as in Example 2. As a result, the plated molded body of this comparative example was swollen in the plated film in the fifth cycle of the heat shock test.

From a comparison between Example 2 and Comparative Example 2, it was confirmed that heat cycle resistance was improved along with plating reactivity and adhesion strength of the plating film by containing CNF in the molded body.

[Example 3]
In this example, the resin pellets (manufactured by Unitika) used in Example 2 were subjected to foam molding using pressurized nitrogen as a physical foaming agent. Application of an electroless plating catalyst and electroless plating were performed in this order on the obtained foamed molded article to obtain a plated part of this example.

(1) Production apparatus for foam molded article First, a production apparatus for producing a foam molded article used in this example will be described. In the present embodiment, a foam molded body is manufactured using a manufacturing apparatus (injection molding apparatus) 2000 shown in FIG. The manufacturing apparatus 2000 mainly includes a plasticizing cylinder 410 in which a screw (plasticizing screw) 40 can be rotated and moved forward and backward, and a cylinder that is a physical foaming agent supply mechanism that supplies a physical foaming agent to the plasticizing cylinder 410. 400, a mold clamping unit (not shown) provided with a mold, and a control device (not shown) for controlling the operation of the plasticizing cylinder 410 and the mold clamping unit. The molten resin plasticized and melted in the plasticizing cylinder 410 flows from the right hand to the left hand in FIG. Therefore, in the plasticizing cylinder 410 of this embodiment, the right hand in FIG. 4 is defined as “upstream” or “rear”, and the left hand is defined as “downstream” or “front”.

On the upper side surface of the plasticizing cylinder 410, a physical foaming agent for introducing a resin supply port 401 for supplying a thermoplastic resin to the plasticizing cylinder 410 and a physical foaming agent into the plasticizing cylinder 410 in order from the upstream side. An introduction port 402 is formed. The resin supply port 401 and the physical foaming agent introduction port 402 are provided with a resin supply hopper 411 and a container 412, respectively. The cylinder 400 is connected to the container 412 via a pressure reducing valve 451 and a pressure gauge 452. The nozzle tip 49 of the plasticizing cylinder 410 is provided with a shut-off valve 48 that opens and closes by driving the air cylinder, so that the inside of the plasticizing cylinder 410 can be held at a high pressure. A die (not shown) is in close contact with the nozzle tip 49, and molten resin is injected and filled from the nozzle tip 49 into a cavity formed by the die.

Within the plasticizing cylinder 410, a feed part 41, a compression part 42, a flow rate adjustment part 43, a starvation part 44, and a recompression part 45 are formed in order from the upstream side, and between the compression part 42 and the flow rate adjustment part 43. Is provided with a seal ring S3 for preventing the backflow of the molten resin and the foaming agent. A resin supply port 401 is formed in the feed unit 41, and the resin pellets supplied from the resin supply port 401 to the feed unit 41 are plasticized and melted and pressurized in the compression unit 42. The screw 40 located in the compression part 42 has a structure in which the screw flight depth becomes shallower as it goes downstream. Due to the structure of the screw 40, the compression portion 42 is pressurized while the molten resin flows, and the amount of resin supplied downstream is limited. By restricting the supply amount of the molten resin downstream in the compression unit 42, the molten resin is starved in the downstream starvation unit 44. A physical foaming agent (pressurized nitrogen) at a constant pressure is always introduced into the plasticizing cylinder 410 from the physical foaming agent introduction port 402 provided in the starvation part 44, and the molten resin in the flow rate adjusting part 43 and the starvation part 44. And penetrates into the molten resin. The molten resin infiltrated with the physical foaming agent is repressurized by the recompression unit 45 and then injected and filled into a mold to obtain a foamed molded product.

In the starvation part 44, since the molten resin is not full (starved state), a constant pressure physical foaming agent (pressurized nitrogen) is always supplied from the physical foaming agent inlet 402 to a space where no molten resin exists. Contact with. The physical foaming agent dissolves in the molten resin while pressurizing the molten resin at a constant pressure. As described above, in the molding apparatus 2000 of this example, the physical foaming agent and the resin are not kneaded with a high shearing force, but the low-density molten resin is contacted with the physical foaming agent to The physical blowing agent can be dissolved to saturation solubility. The depth of the screw flight of the starvation part 44 was set deeper than other parts, and the starvation state of the molten resin was promoted.

In the starvation part 44, it is preferable to send the molten resin downstream at a higher flow rate than the compression part 42 and the like in order to make the molten resin starved. For this reason, in the starvation part 44, although the contact area of molten resin and a physical foaming agent increases, contact time is shortened. In order to compensate for the contact time between the molten resin and the physical foaming agent and sufficiently dissolve the physical foaming agent in the molten resin, in the molding apparatus 2000 of the present embodiment, the flow rate adjusting unit 43 is provided upstream of the starvation unit 44. . In the flow rate adjusting unit 43, the screw 40 located there is provided with a portion where the depth of the screw flight is shallow and a portion where the depth is deep. This screw structure becomes the flow resistance of the molten resin, and the flow rate adjusting unit 43 decreases the flow rate of the molten resin, and the contact time between the molten resin and the physical foaming agent can be extended.

(2) Molding of Foam Molded Body In this example, a nitrogen cylinder filled with nitrogen at 15 MPa was used as the cylinder 400. First, the cylinder 400 was opened, the pressure of nitrogen was adjusted by the pressure reducing valve 451 so that the pressure indicated by the pressure gauge 452 was 2 MPa, and pressurized nitrogen was supplied to the starvation unit 44 via the container 412. In FIG. 4, the pressurized nitrogen (physical foaming agent) supplied into the molding apparatus 2000 is shown as PFA (the area of the dot pattern in FIG. 4). During the production of the molded body, the cylinder 400 was always open.

In the foam molding of this example, the plastic pellets were plasticized and melted and measured under the conditions of a screw rotation speed of 50 rpm, a resin temperature of 250 to 280 ° C., and a back pressure of 5 MPa. First, resin pellets were supplied from the resin supply port 401 of the plasticizing cylinder 410 to the feed unit 41, and plasticized, melted and pressurized by the compression unit 42. Thereafter, the molten resin was caused to flow to the flow rate adjusting unit 43 and the starvation unit 44 by the rotation of the screw 40. In the flow rate adjusting unit 43 and the starvation unit 44, the physical foaming agent was infiltrated into the molten resin by bringing a physical foaming agent having a constant pressure (2 MPa) into contact with the molten resin. In FIG. 4, the molten resin in the molding apparatus 2000 is indicated as R (the hatched area in the plasticizing cylinder 410 in FIG. 4).

The molten resin infiltrated with the physical foaming agent was sent to the recompression unit 45 and recompressed, and the molten resin for one shot was measured at the tip of the plasticizing cylinder 410. Thereafter, the shut-off valve 48 is opened, and the molten resin is injected and filled into the cavity of the mold so as to have a filling rate of 90% of the volume of the cavity, and without holding pressure, 60 mm × 80 mm × 2 mm. A flat foam molded article was molded (short shot method).

The swirl mark confirmed on the surface of the obtained foamed molded product was small, and it was confirmed that the adverse effect of foam molding on the appearance of the molded product was small. Moreover, the cross section of the molded object was observed with SEM. As a result, the average cell diameter was as fine as about 30 μm.

(3) Application of electroless plating catalyst and electroless plating In this example, the electroless plating catalyst was prepared in the same manner as in Example 1 except that the electroless plating time was 3 minutes shorter than that of Example 1. Application, electroless plating, displacement copper plating and electrolytic copper plating were performed to obtain a plated molded body. The electroless plating film was formed on the entire surface of the molded body.

The adhesion strength of the plating film was measured by the same method as in Example 1. As a result, the adhesion strength of the plating film was 10 N / cm. Although this result is a lower value than Example 2, it is practically sufficient strength. According to the study by the present inventors, the adhesive strength of the plating film formed on the surface of the foamed molded product tends to be lower than that of the non-foamed molded product regardless of the presence or absence of CNF. The cause of this is not clear, but is presumed as follows. When the plated molded body after the adhesion strength measurement (after the tensile test) is observed, the peeling interface of the plated film exists not inside the foamed molded body (resin) and the plated film, but inside the foamed molded body. From this result, it is presumed that in the foamed molded product, the skin layer of the molded product becomes brittle, and thus the adhesion strength of the plating film is lowered.

Since the method for producing a plated molded body of the present invention can provide a molded body having high plating reactivity, an electroless plated film can be formed by a method with low environmental burden and cost. Furthermore, the obtained plated molded body has a plating film with high adhesion strength and has high heat cycle resistance. Therefore, the plated molded body produced according to the present invention can be widely used for applications requiring high durability.

11 Double plunger pump 12 Back pressure valve 13, 14 Pressure gauge 20 Screw 20A Pressure holding part 21 Plasticization zone 21A Feed part 21B Compression part 22 High pressure kneading zone 23 Decompression zone 23A Slow pressure reduction part 23B Starvation decompression part 24 Recompression zone 29 Die 31 Half seal ring 33 Poppet valve 34 Belleville spring 100 Supply mechanism 200 Extruder 201 Resin supply port,
202 Introduction Port 203 Vent 210 Plasticizing Cylinder 211 Resin Supply Hopper 212 Introducing Valve 213 Vent Container 1000 Manufacturing Device A Liquid P Vacuum Pump S1 Upstream Seal Mechanism S2 Downstream Seal Mechanism 40 Screw (Plasticization Screw)
41 Feed unit 42 Compression unit 43 Flow rate adjustment unit 44 Starvation unit 45 Recompression unit 48 Shutoff valve 49 Nozzle tip 400 Cylinder 401 Resin supply port 402 Physical foaming agent introduction port 410 Plasticizing cylinder 411 Resin supply hopper 412 Container 451 Depressurization Valve 452 Pressure gauge 2000 Manufacturing equipment (injection molding equipment)
PFA Physical foaming agent R Molten resin S3 Seal ring

Claims (10)

1. A method for producing a plated molded body,
   Molding a thermoplastic resin containing cellulose nanofibers to obtain a molded body;
   Contacting the molded body with an electroless plating catalyst solution containing a metal salt;
   A manufacturing method comprising: bringing an electroless plating solution into contact with the formed body in contact with the electroless plating catalyst solution to form an electroless plating film on a surface of the formed body.
2. The manufacturing method according to claim 1, further comprising subjecting the molded body to a swelling treatment or an etching process before contacting the molded body with the electroless plating catalyst solution.
3. 3. The method according to claim 1, wherein the metal salt contained in the electroless plating catalyst solution is one selected from the group consisting of palladium chloride, silver chloride, copper chloride, and silver nitrate. .
4. The production method according to any one of claims 1 to 3, wherein the thermoplastic resin includes polyamide, polypropylene, or ABS resin.
5. Forming the molded body,
   Preparing a resin pellet containing the thermoplastic resin and the cellulose nanofiber;
   The manufacturing method according to any one of claims 1 to 4, further comprising: molding the resin pellets to obtain the molded body.
6. Preparing the resin pellets,
   Obtaining a mixture of a molten resin obtained by plasticizing and melting the thermoplastic resin and a slurry in which the cellulose nanofibers are dispersed in a solvent;
   Removing the solvent from the mixture;
   Extruding the mixture from which the solvent has been removed to obtain an extruded product;
   The manufacturing method according to claim 5, comprising pulverizing the extruded product to obtain the resin pellets.
7. Preparing the resin pellets,
   The manufacturing method according to claim 6, further comprising adding water to the mixture of the molten resin and the slurry.
8. A plated molded body,
   A molded body containing a thermoplastic resin and cellulose nanofibers;
   A plated molded body comprising an electroless plated film formed on the surface of the molded body.
9. The plated molded body according to claim 8, wherein the molded body is a foamed molded body having foamed cells therein.
10. The plated molded body according to claim 8 or 9, wherein the thermoplastic resin contains polyamide, polypropylene, or ABS resin.

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