JP2010069761A - Method of manufacturing resin-molded component with metal film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a manufacturing method in which a metal film having high adhesion can be formed to a resin-molded component versatilely in spite of materials, etc. of the resin-molded component by economical treatment using an electroless plating liquid of ordinary pressure. <P>SOLUTION: The manufacturing method comprises step of (S1) installing a resin sheet 10 formed of a polyamide-based resin in which metal fine particles are dispersed on at least one surface in a die 73 shaping a resin-molded component 5 in a state that the polyamide-based resin touches the die 73, (S2) filling the die 73 with a resin sheet 10 installed with a molten resin to shape the resin-molded component 5 in which the resin sheet 10 and the molten resin are integrated, and (S3) immersing the resin-molded component 5 in the electroless plating liquid containing alcohol at ordinary pressure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a resin molded product having a metal film.

  In recent years, an attempt has been made to form a light reflector such as a reflector of an automotive headlamp unit from a resin material. In this case, it is necessary to form a metal film on the surface of the resin molded product. At the same time, an attempt has been made to use a thermoplastic resin such as a polyester resin or a polycarbonate resin excellent in mass productivity instead of the thermosetting resin. Since the temperature in the headlamp unit rises due to the heat generated by the lamp, the reflector is required to have heat resistance that does not cause the metal reflective film to peel off even at a temperature of 160 ° C to 180 ° C.

  As a method of forming a metal reflective film on a resin molded product, there is a method of depositing metal after activating the surface of the molded product by plasma activation treatment (direct vapor deposition method). However, when a metal film is formed on a resin molded product such as a headlamp unit or a base material of a headlamp reflector by this method, the resin molded product is exposed to a high temperature environment for a long time. There was a problem that the metal film peeled off and the metal film became cloudy. Possible causes of the metal film peeling include, for example, thermal expansion and deformation of the base polymer, generation of heat decomposition gas in the polymer, and the like.

  As a method for suppressing the generation of pyrolysis gas in the base polymer, for example, a technique for improving the resin component is disclosed (Patent Document 1). And in this resin composition of patent document 1, generation | occurrence | production of the thermal decomposition gas in a base polymer is suppressed by making terminal carboxyl group amount into a specific amount or less. However, the resin component of Patent Document 1 does not contain a release material. Therefore, when a large and complicated (or highly accurate) three-dimensional molded product such as a headlamp unit or a headlamp reflector is molded using the resin having the composition of Patent Document 1, a mold release failure occurs. The molded product cannot be formed into a desired shape. Patent Document 2 discloses a technique for improving the release property of a resin molded product by improving the release agent of the resin component.

  In addition to the automotive headlamp unit and reflector described above, the resin molded product having a metal film includes, for example, an fθ mirror used for optical scanning in a laser beam printer, a copying machine, etc., and a large-sized optical path used for projection TV. There are mirrors. Conventionally, in these plastic mirrors, a highly accurate mirror surface of a molding die is transferred to the surface of a resin molded product, and a metal reflective film is formed on the surface of the resin molded product by vapor deposition or the like.

  However, when the metal reflective film is formed by vapor deposition or the like, the equipment cost is high because the vapor deposition apparatus is expensive. In particular, when forming a molded product with a large area, the number of molded products that can be formed in one batch (one vapor deposition process) is reduced, so that the productivity is poor and an expensive vapor deposition apparatus is required to ensure mass productivity. It was necessary to use multiple units.

  In the past, alternative methods have been disclosed to overcome the cost problems of this deposition method. One alternative method is a method of injecting and filling a thermoplastic resin into a molding die after installing a metal sheet in the molding die (Patent Document 3). In the insert molding method of the metal sheet, the metal sheet and the thermoplastic resin can be integrated in the mold, so that a vapor deposition process after molding is not necessary. However, with this method, the reflectance of the metal sheet that functions as the reflecting surface is lowered. In addition, since the metal sheet that functions as the reflective surface is formed into a desired mirror shape by being brought into close contact with the mold, even if the metal sheet is brought into close contact with the mold by vacuum suction in the mold. It has been difficult to properly adhere (trace) a metal sheet to a complicated three-dimensional mold such as a free-form surface. Therefore, the quality of the plastic mirror obtained by this alternative method was inferior to that obtained by the vapor deposition method.

  As another alternative method, there is a method in which a metal reflection film obtained by vapor-depositing a metal reflection film such as aluminum or silver on a resin film is used for insert molding instead of a metal sheet (Patent Document 4). By using a metal reflective film instead of the metal sheet, the reflectance of the reflecting surface can be increased as compared with the case where the metal sheet is used. However, even if a metal reflective film is used instead of the metal sheet, it is difficult to properly adhere (trace) the metal reflective film to a complicated three-dimensional mold such as a free-form surface. In addition, when the shape of the molded product is a complicated shape such as a free curved surface, excessive tension acts on the film in the process of deforming the deposited film into a curved shape during molding, and the metal reflective film deposited on the film In some cases, cracks occurred. This phenomenon is caused by the fact that the metal binding force in the metal film formed on the film by vapor deposition or the like is weaker than the metal binding force in the metal sheet.

  In addition, in order to avoid the crack of the metal film of a metal reflective film, it is also possible to heat-press the metal reflective film to a molded resin molded product as in Patent Document 5, but even in this case, the metal Since there is no change in transforming the reflective film into a desired shape, it cannot be guaranteed that no cracks will occur in the metal film during thermocompression bonding (pressing). In addition, since a thermocompression bonding (pressing) process is required as a separate process after injection molding, the mass productivity is lower than the two alternative methods described above.

  By the way, besides the vapor deposition method and the alternative method described above, a metal film can be formed on a resin molded product by using an electroless plating method. In the electroless plating method, since the molded product is immersed in an electroless plating solution, a metal film can be formed at a lower cost than the vapor deposition method. Moreover, even if the shape of the resin molded product is a complicated shape such as a free-form surface, a metal film can be formed on the surface of the complicated shape.

  However, in the electroless plating method, it is necessary to roughen the surface of the resin molded product with an etching solution such as chromic acid before the plating treatment, so that the usable resin is limited to ABS resin that can be immersed in the etching solution. It is done. In addition, although other materials such as polycarbonate are commercially available in grades that can be electrolessly plated, these materials are obtained by mixing polycarbonate or the like with ABS or an elastomer. And even if a molded product is obtained with these materials, the heat resistance required for the reflector and the reflection performance required for the mirror could not be obtained.

  In addition, the present inventors have proposed another method for improving the electroless plating method to form a metal film on a resin molded product (Patent Document 6). In this unique method, first, metal fine particles such as a metal complex are dissolved in carbon dioxide such as a supercritical fluid, and then the metal fine particles and the supercritical fluid are introduced into a mold during injection molding. Electroless plating catalyst nuclei are segregated on the surface. Next, the resin molded product is immersed in an electroless plating solution. As described above, since the electroless plating catalyst core is provided on the surface of the resin molded product manufactured by the injection molding method, the electroless plating can be performed without performing pre-etching treatment. Further, even when a material that is not immersed in the etching solution is used as the resin material of the resin molded product, electroless plating is possible.

  The inventors also proposed another method (Patent Document 7). In another method, first, metal fine particles such as a metal complex are dissolved in carbon dioxide such as a supercritical fluid, and the metal fine particles and the supercritical fluid are brought into contact with a resin sheet during extrusion to disperse the metal fine particles. A resin sheet is prepared. Next, the resin sheet is insert-molded to segregate electroless plating catalyst nuclei on the surface of the resin molded product. Further, the resin molded product is immersed in an electroless plating solution. Even in this method, since the electroless plating catalyst core is imparted to the surface of the resin molded product produced by the injection molding method, electroless plating is possible without performing pre-etching treatment, and it is immersed in an etching solution. Electroless plating is possible even when materials that are not used are used.

  However, when electroless plating is performed on the resin molded product manufactured by the methods of Patent Documents 6 and 7 under a normal pressure environment, the plating grows from the catalyst core on the surface of the resin molded product, and the resin A metal film having high adhesion to the molded product could not be formed. In order to form a metal film having high adhesion, it was necessary to mix supercritical carbon dioxide with the electroless plating solution. And since supercritical carbon dioxide is used, expensive apparatuses, such as a high-pressure vessel, were required.

  In addition, a method (Patent Document 8) in which a resin sheet on which a pattern is printed with ink is preformed and mounted in a mold during molding or by insert molding is known (Patent Document 8). However, in order to maintain the printed state of the pattern, it is necessary to prevent the printed sheet from being bent greatly during molding. Also, if the entire printed sheet is dissolved at the time of preforming or molding, the printing will not remain clean.

JP 2000-35509 A JP 2005-97563 A JP-A-5-315829 JP-A-3-82513 JP 2004-148638 A Japanese Patent No. 3866102 Japanese Patent No. 3914961 JP 7-156197 A

  As described above, when a direct vapor deposition method or a vapor deposition method is employed to form a metal film on a resin molded product, the vapor deposition apparatus is expensive, resulting in an increase in production cost. In addition, the metal film formed by the direct vapor deposition method was peeled off when the molded product was used in a heated environment. Further, in an alternative method in which a metal sheet or a metal reflection film and a resin are integrally formed, a complicated metal film such as a free-form surface that requires high surface accuracy cannot be formed. In electroless plating, resin materials that can be used for pre-etching treatment for surface roughening are limited, and the use of supercritical carbon dioxide in combination with resin materials that can be used increases versatility. Even if an expensive high-pressure vessel or the like is not used, a metal film having high adhesion cannot be formed.

  The present invention has been made in order to solve the above-mentioned problems, and has high adhesion for general purposes regardless of the material of the resin molded product by inexpensive treatment using an electroless plating solution at normal pressure. The object is to obtain a production method capable of forming a metal film on a resin molded product. Moreover, this invention is providing the manufacturing method which can form a metal film with a desired pattern further with respect to a resin molded product.

  According to an aspect of the present invention, there is provided a method for producing a resin molded article having a metal film, wherein at least one surface of the resin sheet is formed of a polyamide-based resin in which metal fine particles are dispersed. In the mold for molding the resin, the polyamide-based resin is placed in contact with the mold, the molten resin is filled in the mold in which the resin sheet is placed, and the resin sheet and the above There is provided a production method including molding the resin molded product formed by integrating a molten resin and immersing the resin molded product in an electroless plating solution containing alcohol under normal pressure.

  In this aspect, the resin sheet and the molten resin are integrated so that the polyamide resin in which the metal fine particles are dispersed is on the surface to form a resin molded product, and the resin molded product is further immersed in an electroless plating solution. Thus, a metal film can be formed on a resin molded product by growing plating from metal fine particles dispersed in a polyamide-based resin.

  Moreover, since polyamide has high water absorption and the plating solution penetrates, it is possible to grow plating from metal fine particles dispersed in a hydrophilic polyamide resin. Therefore, a metal film can be formed on a resin molded product for general purposes regardless of the material of the molten resin constituting the resin molded product. For example, even when a hydrophobic resin material that cannot form a metal film with an electroless plating solution is used as the molten resin, the metal film can be formed on a resin molded product made of this hydrophobic resin material.

  In this embodiment, the method of electroless plating, the type of electroless plating solution, and the like are arbitrary. For example, known copper plating, nickel phosphorus plating, Rickel-boron plating, cobalt plating, palladium plating, and the like can be used. . Among these, nickel phosphorus plating is preferable because the adhesion of the metal film is increased.

  By the way, when alcohol is mixed in the electroless plating solution, the reaction rate of plating becomes slow. The reason for this is not clear, and it is presumed that the metal ions such as nickel sulfate are dissolved in water molecules and alcohol that does not dissolve the metal ions is surrounded, so that the metal ions are difficult to reduce. In addition, when an alcohol is added, the plating bath becomes unstable, for example, metal ions are deposited. Therefore, the alcohol is not usually mixed with the electroless plating solution. However, in this method, alcohol is intentionally mixed with the electroless plating solution. Accordingly, the plating growth can be delayed, and the electroless plating solution can be deeply penetrated into the hydrophilic polyamide-based resin, so that the plating can be grown from the metal fine particles inside the resin sheet. As a result, a metal film grown from the inside of the resin molded product (resin sheet) can be formed, and plating is grown from metal fine particles on the surface (outermost surface) of the resin molded product (resin sheet) because no alcohol is used. Compared to the case, the adhesion strength between the resin molded product and the metal film can be remarkably increased. In addition, by mixing alcohol with the electroless plating solution in this way, a metal film having high adhesion can be formed without applying high pressure to, for example, an electroless plating solution or a resin molded product. A metal film having high adhesion can be formed at a low cost by performing electrolytic plating.

  In this embodiment, the alcohol mixed with the electroless plating solution is arbitrary, but an alcohol having a low surface tension is desirable from the viewpoint of easy penetration into the polyamide-based resin. The surface tension of the alcohol is desirably at least smaller than the value of water (73 dyn / cm, 20 ° C.), and more desirably, the surface tension at 20 ° C. is 50 dyn / cm or less. Examples of such an alcohol include ethanol (22.3 dyn / cm), 2 propanol (23.8 dyn / cm), ethylene glycol (46.5 dyn / cm), 2-methoxyethanol (31.8 dyn / cm), 2-ethoxyethanol (28.2 dyn / cm), 1-methoxy-2-propanol (27.1 dyn / cm), 1-ethoxy-2-propanol (25.9 dyn / cm), 1,3-butanediol (37.8 dyn) / Tert-butyl alcohol (19.45 dyn / cm), 2 (2-methoxypropoxy) propanol (28.8 dyn / cm), and the like.

  Further, from the viewpoint of heating to a high temperature (plating reaction temperature) by mixing with a plating solution, it is desirable that the flash point and boiling point of the alcohol be higher than the plating temperature. In the case of electroless nickel phosphorus plating, since the plating temperature is about 60 to 90 ° C, alcohol having a boiling point of 60 ° C and a flash point of 40 ° C or higher is desirable. Examples of the alcohol having a low surface tension and satisfying this temperature condition include 1,3-butanediol (boiling point: 207.5 ° C., flash point: 121 ° C.), 2-methoxyethanol (boiling point: 124.6 ° C.). , Flash point: 43 ° C., 1-ethoxy-2-propanol (boiling point: 132.2 ° C., flash point: 43 ° C.), 2 (2-methoxypropoxy) propanol (boiling point: 190.0 ° C., flash point: 74 ° C.) )and so on.

  In addition, although the mixing amount of alcohol in a plating solution is arbitrary, the mixing amount of 20 vol% or more and 60 vol% or less is desirable. When the amount of alcohol mixed is less than 20 vol%, the high permeability of the plating solution with respect to the polyamide resin cannot be obtained. Moreover, it is because it will become easy to isolate | separate alcohol and a plating solution when it is more than 60 vol%.

  As described above, in this embodiment, the resin sheet formed of the polyamide-based resin in which the metal fine particles are dispersed is used to disperse the metal fine particles serving as the electroless plating catalyst core in the resin molded product itself, and then, under normal pressure. Since the electroless plating of the resin molded product is performed, a metal film can be formed on the molded product for general purposes regardless of the molten resin (resin material) and the shape of the molded product. In addition, since the metal film grows from the inside of the resin molded product to obtain a high anchoring effect, it has high adhesion. Therefore, when molding automotive headlamp units and their reflectors that require heat resistance and durability, when molding mirrors for optical components that require complex shapes such as high reflectance characteristics and free-form surfaces, When molding molded products that require durability such as decorative plating, when molding MID (Molded Interconnect Device) or electromagnetic shield moldings that form electrical circuits on the surface of resin molded products, etc. It can be suitably used.

  In addition, in the manufacturing method of this aspect, the metal film is formed without using a dry process such as vapor deposition or a high-pressure vessel, so that a resin molded product having the metal film can be manufactured by an inexpensive process. In addition, since the resin molded product is simply immersed in an electroless plating solution under normal pressure, even if the molded product has a large area and / or a complicated shape, it has a highly adhesive metal film. Resin molded products can be mass produced.

  In this embodiment, the resin molded product may be immersed in an aqueous solution in which the reducing agent is dissolved before the resin molded product having the polyamide resin on the surface is immersed in the alcohol-containing plating solution. By this electroless plating pretreatment, the plating solution easily penetrates into the polyamide-based resin formed on the surface of the resin molded product and provided with catalyst nuclei. Moreover, the plating reactivity inside a polyamide-type resin can be improved. Therefore, the adhesion of the plating film is further increased. For this reason, the reducing agent dissolved in water molecules is unlikely to be present on the polyamide surface, and is presumed to exist in the polyamide within a short time until the plating treatment. Therefore, it is considered that the reduction reaction of the plating is more likely to occur inside the polyamide than the surface. As the reducing agent used for this pretreatment, a reducing agent that can be used for plating is desirable, and for example, hypophosphorous acid, sodium hypophosphite, sodium borohydride, formalin, hydrazine, dimethylamine borane, and the like are desirable. Particularly when nickel phosphorus plating is performed, hypophosphorous acid or sodium hypophosphite is desirable as a pretreatment reducing agent.

  In addition, the resin sheet used in this embodiment may be any sheet as long as at least one surface is formed of a polyamide-based resin in which metal fine particles are dispersed. For example, a sheet formed of a single layer of a polyamide-based resin Or the sheet | seat with which the layer of the polyamide-type resin and the layer of other resin overlapped may be sufficient. In particular, the other surface of the resin sheet may be formed of a resin different from the polyamide-based resin and melt-bonded to the molten resin filled in the mold. For example, in the case of a resin sheet in which a highly polar polyamide resin and a resin with a non-polar material with low adhesion are stacked, the other surface (adhesive surface) of the resin sheet is made of a resin that is easily compatible with the molten resin filled in the mold. Therefore, the filling resin and the resin sheet can be more firmly integrated in the mold. In addition to this, an adhesive layer (resin component) that increases the compatibility of each resin between these resin sheets is obtained by laminating the polyamide resin sheet and the resin sheet on the other surface by a multilayer coextrusion molding method. A resin sheet may be included. Also, in order to improve the adhesion between the molten resin filled in the mold and the resin sheet, a functional group was imparted to the other surface (adhesive surface) of the resin sheet by UV treatment, corona discharge treatment, plasma treatment, or the like. A resin sheet may be used. The resin sheet may be molded by extrusion molding or may be molded by a casting method. In addition, since the resin sheet may be semi-melted with hot air in the mold and attached to the mold, a non-stretchable and highly flexible sheet is desirable.

  The type of polyamide resin in the resin sheet is arbitrary, and may be nylon 6, nylon 6, 6, nylon 46, nylon 11, nylon 12, nylon MXD6, nylon 6T, nylon 9T, aramid resin, or the like. Among these, nylon 6 (melting point 225 ° C.) or nylon 66 (melting point 265 ° C.) is desirable from the viewpoint of cost and ease of manufacture and handling.

  The metal fine particles may function as a catalyst nucleus for electroless plating, and may be at least one fine particle selected from, for example, palladium complex, modified palladium complex, and palladium metal fine particles.

  The resin sheet may have a thickness of 10 to 200 μm. When the resin sheet is thinner than 10 μm, the resin sheet is easily broken partially when the filled resin comes into contact, the quality is not stable, and mass productivity is impaired. Also, when the resin sheet is made thinner than 200 μm, the resin sheet is melted as a whole and filled after cooling by filling the molten thermoplastic resin into the mold with the resin sheet installed in the mold. Can be integrated with the resin. Note that the temperature of the resin to be filled is, for example, 200 ° C. or higher, more preferably 230 ° C. or higher, which is the softening temperature of the polyamide resin.

  Also, if the resin sheet is made thinner than 200 μm, the resin sheet can be easily deformed and can be in close contact with the mold, so that the resin sheet floats from the mold or when the molten resin is filled in the mold. It becomes difficult to break the part. As a result, a resin molded product having a shape based on the shape of the mold can be mass-produced. For example, even if the mold has a complicated shape such as a free-form surface, a resin molded product having a shape obtained by transferring the complicated shape can be mass-produced. Moreover, since the surface of the resin molded product having a complicated shape is composed of a polyamide-based resin in which metal fine particles are dispersed, a metal film can be formed by electroless plating at normal pressure containing alcohol. A metal film having high adhesion to a resin molded product can be formed at low cost.

  In addition, as the resin molded product manufactured in this aspect, a resin molded product having a surface of a polyamide-based resin that can be in close contact with a metal film formed by plating, and an interior formed from a resin having a lower thermal expansion coefficient or water absorption than polyamide Can be formed. In such a resin structure, a dimensional change due to heat or moisture of the polyamide resin can be suppressed by making the resin sheet containing the polyamide resin thin by 200 μm or less. Therefore, compared to the case where a resin molded product is formed using only a polyamide-based resin, it is possible to suppress the peeling and cracking of the metal plating film due to thermal shock, and the change in the optical characteristics of the metal film due to the dimensional change due to moisture absorption. Can be suppressed.

In particular, when the resin sheet has a thickness of 10 to 150 μm, before filling the mold with the molten resin, the resin sheet placed in the mold is heated, pressurized, or vacuumed. The method may include bringing the resin sheet into close contact with the mold by one method. For example, the resin sheet installed in the mold may be heated by applying hot air to the resin sheet installed in the mold. Alternatively, if the mold temperature is high to some extent or the pressurizing force is high, the sheet can be traced on the mold surface by spraying a pressurized gas such as pressurized air or N ₂ on the sheet. Or a thin sheet | seat can be closely_contact | adhered to a metal mold | die by vacuum-sucking for a short time. You may employ | adopt these methods in combination.

  Since a resin sheet having a thickness of 150 μm or less is easily softened by heat, the resin sheet can be fixed to the surface of the mold as a thin film by blown with hot air in the mold. Further, the resin sheet is in close contact with the mold without any gap. Accordingly, since the molten resin can be filled into the mold in a state where the resin sheet is in close contact with the mold, a resin molded product having a shape in which the mold is transferred can be molded while preventing the resin sheet from being damaged. Moreover, since the resin sheet is molded in the mold using hot air, it is not necessary to mold the resin sheet before it is put into the mold (no need for a preform), and the resin sheet is shaped into the mold. Can be molded with high accuracy. In addition, when the resin sheet becomes thinner than 150 μm, the physical properties of the resin filled in the mold in the resin molded product become more emphasized, so the mechanical properties of the molded product can be selected by selecting the resin filled in the mold. And can incorporate thermal properties. When the thickness of the resin sheet is greater than 150 μm, even if hot air is applied to the resin sheet in the mold, it becomes difficult for the resin sheet to closely adhere to the complex-shaped mold. Therefore, when a resin sheet thicker than 150 μm is used, the resin sheet is molded into a desired shape (preform) according to the shape of the mold before being placed in the mold, and then the mold A resin sheet molded in accordance with the shape may be installed in an injection mold. The sheet thickness required for roughly molding a resin sheet by a known preform method is desirably 50 μm or more from the viewpoint of maintaining the shape after molding to some extent.

  In addition, in this aspect, before the resin molded product is immersed in the electroless plating solution, the polyamide resin is partially removed from the resin molded product by irradiating the resin molded product with a laser. May be.

By irradiating the resin molded product with laser and partially removing the polyamide resin from the resin molded product, the polyamide resin on the surface of the resin molded product can be formed into a desired pattern. For example, a circuit wiring pattern or the like can be formed on the surface of the resin molded product. A metal film having a desired pattern can be formed on the resin molded product by performing the electroless plating at normal pressure on the polyamide-based resin having a desired pattern in this way. Further, since the polyamide-based resin is formed in a desired pattern by laser irradiation, selective plating can be performed in a fine pattern having a narrow line width (a width of several microns to several millimeters). In consideration of ease of removal by laser, the thickness of the polyamide resin (resin sheet) is preferably 100 μm or less, and more preferably 30 μm or less. Examples of lasers that can be used to partially remove the polyamide-based resin include a CO ₂ laser and a YAG laser. Among these, a YAG pulse laser is desirable because a polyamide-based resin can be formed with a fine pattern on the surface of a molded product.

  In this aspect, installing the resin sheet in the mold may include partially installing the resin sheet on a part of the molding surface of the mold.

  By partially installing the resin sheet on a part of the molding surface of the mold, the polyamide-based resin on the surface of the resin molded product can be formed into a desired pattern. A metal film having a desired pattern can be formed on the resin molded product by performing the electroless plating at normal pressure on the polyamide-based resin having a desired pattern in this way. Moreover, since the metal film is formed in a desired pattern by partially disposing the resin sheet itself, if the surface area where the metal film is not formed is large, the polyamide resin is partially removed from the resin molded product with a laser. It is advantageous compared with the case where it removes automatically. As described above, the method of partially disposing the resin sheet is a macro portion (a portion having a large area on the order of several millimeters to several centimeters in width) as compared with the method of partially removing the resin with a laser. The selective plating can be easily realized. Conversely, the method of partially removing the polyamide-based resin from the resin molded product using a laser is advantageous when a fine pattern is formed. In addition, you may use combining the method of arrange | positioning a resin sheet partially, and the method of removing resin partially with a laser.

  By the way, in this embodiment, the method for producing the resin sheet is arbitrary. The resin sheet can be formed continuously by melting and kneading, for example, metal fine particles and polyamide resin pellets with an extruder. In addition, for example, high pressure carbon dioxide in which metal fine particles are dissolved may be brought into contact with a resin sheet made of polyamide resin. Specifically, for example, a batch method in which high-pressure carbon dioxide in which metal fine particles are dissolved and a resin sheet made of a polyamide resin are contacted in a high-pressure container, high-pressure carbon dioxide in which metal fine particles are dissolved, and a molten polyamide-based resin; There is an extrusion molding method in which is contacted and permeated in a mold of an extrusion molding machine. When metal fine particles are dispersed in the resin sheet using high-pressure carbon dioxide, the metal fine particles are uniformly dispersed in the resin sheet. The metal fine particles may be dispersed using a solvent such as alcohol other than high-pressure carbon dioxide.

  Specifically, in the resin sheet extrusion molding method, for example, when a resin sheet having at least one surface formed of a polyamide-based resin is molded by extrusion molding, high-pressure carbon dioxide in which the metal complex that is the source of the metal fine particles is dissolved May be brought into contact with the molten resin before molding or the resin in the extrusion mold. Thereby, the resin sheet in which at least one surface is formed from the polyamide-based resin in which the metal fine particles are dispersed can be generated.

  Specifically, in the resin sheet batch method, for example, a resin sheet having at least one surface formed of a polyamide-based resin is formed by extrusion molding, the resin sheet is accommodated in a high-pressure container, and the metal fine particles are further formed. What is necessary is just to introduce | transduce the high voltage | pressure carbon dioxide in which the metal complex used as this is melt | dissolved in the said high pressure vessel. Thereby, at least one surface of the resin sheet becomes a surface formed from the polyamide-based resin in which the metal fine particles are dispersed. In addition, when a resin sheet is formed by extrusion, a long resin sheet can be formed continuously, so that the metal complex is continuously brought into contact with the long resin sheet to form a metal complex (metal fine particles). It is possible to efficiently mold a resin sheet in which is dispersed. Resin sheets used for a plurality of resin molded products can be formed continuously and collectively. Therefore, it is not necessary to carry out a process of dispersing the metal fine particles for each resin molded product. Moreover, when a resin sheet is formed by extrusion molding, it can be reused by melting and kneading the surplus sheet after insert molding together with the resin pellets.

  Further, in this resin sheet batch method, the polyamide sheet may be wound around a separator made of an inorganic material and accommodated in a high-pressure container. As the separator formed of an inorganic material, for example, an aluminum mesh sheet, a SUS mesh sheet, a glass cloth, or the like is suitable. Since these separators can pass high-pressure carbon dioxide, highly diffusible high-pressure carbon dioxide can diffuse and penetrate evenly over the entire surface of the polyamide sheet through the separator.

  In this way, after dissolving fine metal particles such as a metal complex in high-pressure carbon dioxide in a liquid or supercritical state, the polyamide-based resin layer of the resin sheet is damaged by bringing the high-pressure carbon dioxide into contact with the resin sheet. The metal fine particles can be quickly diffused (dispersed) inside the resin sheet without giving them and without aggregating the metal fine particles in the resin sheet. Further, since the metal complex is dissolved in the resin sheet after being dissolved in high-pressure carbon dioxide, the metal complex can be uniformly dispersed in the resin sheet without using an organic solvent.

  Examples of the metal complex include bis (cyclopentadienyl) nickel, bis (acetylacetonato) palladium (II), dimethyl (cyclooctadienyl) platinum (II), and hexafluoroacetylacetonatopalladium (II). , Hexafluoroacetylacetonatohydrate copper (II), hexafluoroacetylacetonatoplatinum (II), hexafluoroacetylacetonato (trimethylphosphine) silver (I), dimethyl (heptafluorooctaneconate) silver (AgFOD), etc. Can be used. Among these, a palladium complex is preferable because it is balanced in terms of cost and function as a catalyst core for plating.

Further, although the metal complex is infiltrated into the resin sheet, the metal fine particles in the resin sheet at the time of electroless plating may be those obtained by modifying the metal complex into its oxide or the like. Further, in order to increase the catalytic activity of plating, a method of metalizing a metal complex in a polyamide resin layer (resin sheet) which may be metalized before electroless plating is arbitrary. For example, The polyamide resin layer (resin sheet) may be brought into contact with high-pressure carbon dioxide in which the metal complex is dissolved after the reducing agent has been permeated into the polyamide resin layer (resin sheet). Thereby, the metal complex which permeate | transmitted the polyamide-type resin layer (resin sheet | seat) can be reduce | restored and metallized with low temperature (normal temperature). In addition to this, for example, a high pressure carbon dioxide in which a metal complex is dissolved in a low temperature (normal temperature) high pressure container is brought into contact with the resin sheet to infiltrate the metal complex into the resin sheet, and then the temperature in the high pressure container is increased. Thus, the metal complex that has penetrated into the polyamide resin layer (resin sheet) can be thermally reduced to be metalized. Still further, for example, the metal complex or metal oxide can be reduced and metallized by performing the above-described reduction treatment before the electroless plating treatment.

  As described above, in the present invention, a metal film having high adhesion is formed on a resin molded product for a general purpose regardless of the material of the resin molded product by an inexpensive treatment using an electroless plating solution at normal pressure. it can. Further, in the present invention, a metal film can be formed in a desired pattern on the resin molded product.

  Hereinafter, embodiments of a method for producing a resin molded product having a metal film of the present invention will be described with reference to the drawings. In addition, the Example described below is a suitable example of this invention, and this invention is not limited to this.

  FIG. 2 is a process diagram showing the overall processing flow of the method for producing a resin molded product having a metal film in each of the following examples. In each example, a polyamide-based resin sheet infiltrated with metal fine particles is produced using a batch method or an extrusion molding method (S1), and a preform method (before insert injection molding, before placing in a mold in advance). The method of molding the sheet into the cavity shape of the mold is defined as the preform method or the direct molding method (adhesion of the sheet to the cavity surface in the mold for injection molding before resin filling in insert injection molding) The resin molded product was insert-molded using a method (S2), and a metal film was formed on the resin molded product using an electroless plating solution at normal pressure (S3). Further, a desired metal body was formed by using this metal film as a metal base film, and this metal body was used as a heat radiating body, a conductor or the like of a resin molded product. First, the elemental technology used in each process will be described.

[Production method of polyamide resin sheet using batch method]
In the batch method, a polyamide-based resin sheet in which metal fine particles have permeated is produced by bringing pressurized carbon dioxide in which metal fine particles are dissolved into contact with a polyamide-based resin sheet formed into a sheet shape.

  FIG. 2 is a configuration diagram of a batch apparatus for infiltrating metal fine particles such as a metal complex into the polyamide resin sheet 1. The batch apparatus mainly includes a high-pressure vessel 11 that accommodates a wound long polyamide resin sheet 10, a dissolution tank 12 that accommodates a powdery metal complex, and a liquid carbon dioxide cylinder 13. A hexafluoroacetylacetonatoparadium (II) complex was used as the powdery metal complex.

  The long polyamide resin sheet 10 includes a polyamide resin such as nylon 6 or polyphthalamide, and is formed to have a width of 40 cm and a length of 20 m. Moreover, in the following Examples, it has the thickness in the range of 25-300 micrometers. As shown in FIG. 3, the long polyamide resin sheet 10 is rolled over an aluminum mesh separator 9 and wound around an aluminum cylinder 8 having a large number of holes.

  The long polyamide resin sheet 10 that is wound around the aluminum cylinder 8 so as to overlap the separator 9 is accommodated in the high-pressure vessel 11. At this time, a support cylinder 26 formed in the center of the high-pressure vessel 11 and having a large number of holes is inserted into the aluminum cylinder 8. Thereafter, the lid was closed and the pressure vessel 11 was sealed.

  Next, high-pressure carbon dioxide was introduced into the high-pressure vessel 11 to infiltrate the polyamide resin sheet 10 with the metal complex. Specifically, after the liquid carbon dioxide having a pressure of 6 MPa and a room temperature of 25 ° C. is exhausted from the liquid carbon dioxide cylinder 3 and gasified by passing through the pipe 14 adjusted to 40 ° C., the pressure gauge 16 indicates 20 MPa. Thus, the pressure was increased by the pump 15. Thereby, the internal pressure of the buffer container 17 whose temperature is adjusted to 50 ° C. becomes 20 MPa. The high-pressure carbon dioxide placed in an environment of 20 MPa and 50 ° C. in the buffer container 17 and being in a supercritical state was decompressed by the pressure reducing valve 18 so that the display of the pressure gauge 19 became 15 MPa. When the automatic valve 20 is opened, high pressure carbon dioxide in a supercritical state of 15 MPa is introduced into the sealed pressure vessel 11 from the lower and upper introduction / discharge ports 27 and 28 of the high pressure vessel 11.

  Supercritical carbon dioxide introduced into the high-pressure vessel 11 is circulated between the high-pressure vessel 11 and the dissolution tank 12 by a circulation pump 22. Actually, the circulation pump 22 was driven for several minutes to circulate high-pressure carbon dioxide in the direction of the check valve 21 for several minutes. Since the metal complex is charged in the dissolution tank 12, the metal complex is dissolved in supercritical carbon dioxide in the dissolution tank 12. The supercritical carbon dioxide in which the metal complex is dissolved diffuses into the pressure vessel 11 and permeates the polyamide resin sheet 10. As a result, the metal complex penetrates into the polyamide resin sheet 10.

  Note that the pressure of the back pressure valve 25 was adjusted to 15 MPa in advance. When the pressure of circulating supercritical carbon dioxide decreases, supercritical carbon dioxide is replenished from the automatic valve 20. Thereby, the pressure of the supercritical carbon dioxide circulating through the high-pressure vessel 11 and the dissolution tank 12 is maintained at 15 MPa. The pressure gauge 23 displays 15 MPa, which is the internal pressure of the pressure vessel 11.

  After the metal complex was infiltrated into the polyamide resin sheet 10, the circulation pump 22 was stopped. Further, after holding the high-pressure vessel 11 at 50 ° C. for 30 minutes, the temperature inside the pressure vessel 11 was raised to 120 ° C. with a temperature controller (not shown). As a result, the metal complex that has permeated the polyamide resin sheet 10 is thermally reduced to form metal fine particles, which are fixed to the sheet. In addition, although the internal pressure of the pressure vessel 11 also rises due to the above-described temperature rise, surplus carbon dioxide for this pressure rise escapes from the back pressure valve 25. A centrifugal separator (not shown) is installed at the tip (exhaust side) of the back pressure valve 25, and the metal complex contained in the exhaust and the decompressed carbon dioxide can be separated and recovered. The recovered metal complex can be reused.

  After the metal fine particles were fixed to the polyamide resin sheet 10, the automatic valve 25 was closed and the automatic valve 24 was opened. Thereby, the high-pressure carbon dioxide in the pressure vessel 11 is exhausted. Moreover, after the internal pressure of the pressure vessel 11 returned to normal pressure, the pressure vessel 11 was opened, and the polyamide resin sheet 10 was taken out together with the jig.

  As described above, a long polyamide resin sheet 10 into which the metal complex, its thermal metamorphosis, or metal fine particles have permeated can be obtained by a batch method. Further, the metal fine particles can penetrate substantially uniformly into both surfaces of the polyamide resin sheet 10.

[Production method of polyamide resin sheet using extrusion molding method]
In the extrusion molding method, a pressure-reduced carbon dioxide in which metal fine particles are dissolved is brought into contact with a polyamide resin, and then the polyamide resin after contact is formed into a sheet shape so that the metal fine particles penetrated. Is made.

  FIG. 4 is a configuration diagram of an extrusion molding apparatus for forming a polyamide resin sheet 10 infiltrated with metal fine particles such as a metal complex. The extrusion molding apparatus mainly includes a T die 41 for forming a molten resin into a film (sheet) shape, a plasticizing cylinder 42 for continuously supplying the molten resin to the T die 41, a liquid carbon dioxide cylinder 43, a metal And a container 44 containing a fluorine solution in which 5 wt% of the complex is dissolved.

In the present invention, metal fine particles to be permeated into the resin sheet 10 are arbitrary, but in this example, hexafluoroacetylacetona (II) which is a metal complex was used. In addition, the container 44 contains a liquid fluorine compound Perfluorotripropylamine (molecular formula: C ₁₅ F ₃₃ N (manufactured by Synquest Laboratory, molecular weight: 821.1, boiling point: 220) that is compatible with the metal complex and soluble in high-pressure carbon dioxide. C.) and a metal complex were mixed to contain a fluorine solution prepared so as to dissolve 5 wt% of the metal complex.

  When forming the polyamide resin sheet 10, first, the automatic valve 46 was opened, and a fluorine solution in which 5 wt% of the metal complex was dissolved was sucked into the syringe pump 47 through the filter 45. Further, the pressure of the fluorine solution was increased to 15 MPa in the syringe pump 47. Further, the automatic valve 49 was opened, liquid carbon dioxide was sucked from the liquid carbon dioxide cylinder 43 into the syringe pump 50, and the liquid carbon dioxide was increased to 15 MPa in the syringe pump 50.

  After suctioning the fluid of the same pressure to the two syringe pumps 47, 50, the two syringe pumps 47, 50 are driven while controlling the flow rate ratio to obtain a fluorine solution in which 5 wt% of the metal complex is dissolved and high-pressure carbon dioxide. Mix. Thereby, the metal complex and the fluorine solution are dissolved in the liquid high-pressure carbon dioxide. This mixed fluid (liquid) is supplied to the plasticizing cylinder 42 via the pressure gauge 52, the check valve 53, the manual valve 54 and the introduction port 55. The mixing ratio of the liquid high-pressure carbon dioxide and the fluorine solution in which 5 wt% of the metal complex is dissolved may be, for example, 20: 1.

  In the plasticizing cylinder 42, a single screw 57 having a vent structure for constituting the decompression unit 56 in the cylinder 42 is rotating. Therefore, the polyamide resin pellets supplied from the hopper 58 are plasticized and melted in the plasticizing cylinder 42 adjusted to a temperature of 200 to 230 ° C., and then sent out according to the rotation of the single screw 57, and vented. The pressure is suddenly reduced at the part 56. Further, the mixed fluid is introduced into the plasticizing cylinder 42 in the decompression unit 56. Accordingly, the liquid high-pressure carbon dioxide in which the metal complex and the fluorine solution are dissolved is mixed with the molten resin that has been rapidly depressurized in the decompression section 56. Thereby, the metal complex and the fluorine solution are dispersed in the molten resin.

  The molten resin in which the metal complex and the fluorine solution are dispersed is extruded from the plasticizing cylinder 42 as the single screw 57 rotates, and is formed into a film (sheet) shape by the T die 41. The film (sheet) -like polyamide resin extruded from the T-die 41 passes through the cooling roll 59 and the like, and is wound up. In this example, a non-stretched polyamide resin sheet 10 having a thickness of, for example, 50 μm was formed by adjusting a gap (not shown) at the extrusion port of the T die 41.

  As described above, a long polyamide resin sheet 10 in which a metal complex or the like is dispersed can be obtained by an extrusion molding method. In addition, the shape of the extrusion port of the T die 41 that can be used in the extrusion molding method can be an arbitrary shape. Then, by changing the shape of the extrusion port of the T die 41, a long polyamide-based resin in which a metal complex or the like is dispersed can be formed in a shape other than the sheet.

  Note that the metal complex can be dissolved in pressurized carbon dioxide by further dissolving the high-pressure carbon dioxide after mixing and dissolving the metal complex in the liquid fluorine compound. Further, by dissolving by this method, the mixing ratio of the fluorine solution 42 in which 5 wt% of the metal complex is dissolved and the liquid high pressure carbon dioxide can be made constant, and the amount of the metal complex in the mixed fluid (liquid) can also be made constant. . In the mixed fluid, the metal complex exists in a state protected by a liquid fluorine compound, so that it is difficult for the metal complex to thermally decompose or agglomerate when contacted with a molten resin at a high temperature. The dispersibility of the metal complex in the resin can be prevented from deteriorating. Further, since the fluorine compound has the property of easily bleeding out on the surface of the resin, the metal complex protected by the fluorine compound is likely to segregate near the surface of the resin. In addition, the concentration of the metal complex dissolved in the high-pressure carbon dioxide can be maintained constant without using a dissolution tank that directly contacts the metal complex with the high-pressure carbon dioxide, and it is continuous without interruption to the high-pressure carbon dioxide. A stable amount of the metal complex can be supplied. In addition, the container 44, which is installed upstream of the syringe pump 47, is replenished with a fluorine solution in which 5 wt% of the metal complex is dissolved in the storage container 44 under normal pressure, so that the fluorine solution can be continuously supplied without interruption. Continuous production of the polyamide resin sheet 10 is possible in the molding method.

[Insert molding method for resin molded products using the preform method]
In the insert molding method for a resin molded product, an injection molding apparatus for forming the resin molded product is used. 5 and 6 are cross-sectional views showing a part of the injection molding apparatus. The injection molding apparatus mainly includes a mold 73 that includes a movable mold 71 and a fixed mold 72 and molds a molten tree, and a plasticizing cylinder 74 that injects the molten tree into the mold 73.

  First, a known preform molding was performed in advance. As shown in FIG. 8, in the preform, the resin sheet 10 of FIG. 8 (A) is prepared, and the resin sheet 10 is exposed by an indirect heating source using an infrared heater (not shown) as shown in FIG. 8 (B). After being softened, the resin sheet 10 is stacked on a mold 79 imitating the injection mold 71 shown in FIG. 8C, sprayed with pressurized air at a pressure of 1 MPa, and removed from the mold 79, so that FIG. A box-shaped sheet 10 as shown in FIG.

  Next, the sheet 10 in which metal fine particles were dispersed and preformed was inserted into a mold 71 for injection molding, and insert molding was performed. First, the polyamide resin sheet 10 formed into a box shape by the preform method was brought into close contact with the mold 73. Specifically, the sheet 2 was inserted into the surface of the cavity 13 of the movable mold 33 of the injection mold, and fixed by vacuum suction from the vacuuming groove 34. Thereafter, as shown in FIG. 6, the molten resin in the plasticizing cylinder 74 adjusted to an arbitrary temperature is injected and filled into the mold 73 by the advancement of the screw 75. Thereafter, after the mold 73 was clamped, the mold 73 was released. Thereby, the resin molded product 5 was obtained.

  In the present invention, the type of the filling resin material to be injection-molded by insert (in-mold) molding is arbitrary. For example, synthetic fibers such as polyester, polypropylene, polymethyl methacrylate, polycarbonate, amorphous polyolefin, polyetherimide Polyethylene terephthalate, liquid crystal polymer, ABS resin, polyamidoimide, polylactic acid and other biodegradable plastics, nylon resin and the like, and composite materials thereof can be used. Moreover, the resin material which kneaded various inorganic fillers, such as glass fiber, carbon fiber, nanocarbon, etc. can also be used for filling resin. The filling resin may be the same polyamide-based resin as the resin sheet material or may be different from the resin sheet material, but may be the same material in order to improve the adhesion to the sheet material.

  As described above, a resin molded product 5 having a polyamide resin layer 6 in which metal fine particles are dispersed on the surface can be obtained by using the preform method. In the preform method, the polyamide-based resin sheet 10 is softened and then stretched by blowing pressurized air, and the sheet 10 is deformed into a shape that matches the preform mold 79. Some degree of strength is required. Actually, a sheet having a thickness of 50 μm or more can be maintained in a molded shape without being torn by being stretched by the pressurized air for the preform and after being removed from the preform die 79. Was able to be preformed.

  When a sheet having a thickness of 200 μm or less is used as the polyamide resin sheet 10, the sheet 10 can be melted or thinned by contact with the molten resin during injection molding. Therefore, strictly speaking, the shape of the sheet layer 6 after the injection molding is not maintained in the shape of the sheet 10 before the preform. In addition, even if the shape of the preformed sheet 10 is not a shape that can be in close contact with the mold 73 and the mold 73 is a complicated shape such as a deep drawing, the surface of the mold 73 is traced well. A resin molded product 5 having a simple outer shape can be obtained.

[Insert molding method for resin molded products using the direct molding method]
In the present invention, a thin sheet can be directly molded without a preform that is plastically deformed into a cavity shape immediately before injection molding. Even when the sheet is thin and difficult to maintain its shape, it can be brought into close contact with the mold mirror surface by at least one of heating, pressurization and vacuum.

  In the insert molding method of the present embodiment, after a polyamide-based resin sheet is made to have a desired shape using a jig obtained by tracing the cavity surface shape of a mold, the sheet in that state together with the jig is used in an injection molding apparatus. A resin molded product is obtained by arranging in a mold. Thus, by using a jig to dispose the sheet on the mold of the injection molding apparatus, it is possible to dispose a thin sheet without causing any trouble with respect to the mold of the injection molding apparatus. . In addition, you may arrange | position a sheet | seat directly to the metal mold | die of an injection molding apparatus.

  Specifically, first, as shown in FIG. 8 (A), a polyamide resin sheet 10 in which metal fine particles are dispersed is placed on a fixing jig 81 having the same shape as the molded product. Thereafter, as shown in FIG. 8B, the fixing jig 81 is heated to 150 ° C., the sheet 10 is heated with pressurized and heated air, and provided inside and outside the fixing jig 81. Air was sucked from the vacuum suction groove 82 to fix the sheet 10 to the surface of the fixing jig 81. Thereby, the polyamide resin sheet 10 is formed in the surface shape of the molded product.

  Next, as shown in FIG. 9, the fixing jig 81 to which the sheet 10 is attached is disposed so as to face the movable mold 71, and the fixing jig 81 and the movable mold 71 are further arranged as shown in FIG. 10. While the sheet 2 is sandwiched, the vacuum suction of the fixing jig 81 is cut. Thereafter, the pressurized air is caused to flow on the surface of the fixing jig 81 from another air circuit (not shown), and at the same time, vacuum suction is performed from the vacuum suction groove 76 of the movable mold 71. As a result, as shown in FIG. 11, the sheet 10 formed in the surface shape of the molded product is peeled off from the fixing jig 81 and is in close contact with the movable mold 71. In FIG. 9, the resin sheet 10 is installed only on the movable mold 71, and is partially installed on a part of the molding surface of the mold 73.

  After the polyamide resin sheet 10 is brought into close contact with the movable mold 71 by the direct molding method, as shown in FIG. 12, the mold 73 is closed, and the screw 75 of the plasticizing cylinder 74 adjusted to an arbitrary temperature. Move forward. Thereby, the molten resin of the plasticizing cylinder 74 is injected and filled into the mold 73. Thereafter, after the mold 73 was clamped, the mold 73 was released to obtain the resin molded product 5. For example, as shown in FIG. 13, a reflector-shaped molded product 5 having a concave mirror surface is formed. In FIG. 13, a through hole 4 is formed at the center of the concave mirror surface of the reflector 5, and a part of the polyamide resin sheet 10 protrudes from the through hole 4 toward the right in the drawing. In such a case, the final resin molded product 5 as shown in FIG. 14 can be obtained by cutting the protruding portion.

  As described above, the resin molded product 5 having the polyamide-based resin layer 6 having metal fine particles dispersed on the surface can be obtained by using a direct molding method. In the direct molding method, the polyamide resin sheet 10 is formed into a desired mold shape using the fixing jig 81, and then the polyamide resin sheet 10 is formed on the mold 73 using pressurized air. Since it adheres, even if the polyamide-type resin sheet 10 is a thin thing of 90 micrometers or less, it can be stuck to the metal mold | die 73, without making it break.

[Method for Forming Metal Film on Resin Molded Product Using Alcohol-Containing Normal Pressure Electroless Plating Solution]
Using the preform method or the direct molding method described above, for example, as shown in FIG. 14, a resin molded product 5 having a polyamide-based resin layer 6 in which metal fine particles are dispersed can be obtained. In the resin molded product 5, a plating film (metal base film) can be grown from the metal fine particles inside the molded product 5 by the following electroless plating method. In this example, an electroless Ni—P (nickel phosphorus) plating solution was used.

  First, a reducing solution in which 10% by volume of hypophosphorous acid as a reducing agent is dissolved and pH is adjusted to 7 with NaOH is prepared, and resin molding formed by the above-described preform method or direct molding method on this reducing solution. Product 5 was immersed for 5 minutes. By the reduction treatment before the electroless plating treatment, the hydrophilic polyamide resin layer 6 on the surface of the resin molded product 5 swells, and metal fine particles (palladium) such as a metal complex in the polyamide resin layer 6 are activated. Can be

  Thereafter, the resin molded product 5 taken out from the reducing solution was washed with water to remove the reducing agent attached to the surface of the molded product 5. Next, the resin molded product 5 washed with water was immersed in an electroless nickel phosphorus plating solution containing 45 vol% alcohol. 1,3-butanediol or the like was used as the alcohol, and the temperature of the plating solution was 70 ° C. Nicolon DK manufactured by Okuno Pharmaceutical Co., Ltd. was used as a stock solution for electroless plating.

  As described above, the metal film 3 was formed on the surface of the resin molded product 5 by electroless plating under normal pressure, for example, as shown in FIG. For example, the metal film 3 can be formed on the concave mirror surface of the reflector 5 and the through hole 4 as shown in FIG. Further, a thick metal film can be formed on the base film 3 by performing electrolytic plating or the like using the metal film 3 as a base film. By superimposing another metal film on the base film 3 having the desired pattern, a conductor having desired electrical characteristics can be formed.

  The polyamide resin layer has hydrophilicity. Therefore, without performing the above-described reduction treatment using the reducing agent and the accompanying water washing treatment, the resin molded product 5 insert-molded using the preform method or the direct molding method is immersed in an electroless plating solution under normal pressure as it is. Even so, the metal film 3 can be formed on the resin molded product 5.

  Next, each embodiment using a combination of the above elemental technologies will be described. Table 1 shows combinations of materials and processes used in each example.

  In this embodiment, nylon 6 sheets 10 having a thickness of 25, 50 and 90 μm are prepared, and these sheets 10 are prepared using the above-described batch method using high-pressure carbon dioxide (see FIGS. 2 and 3). Metal fine particles were infiltrated into the glass.

  Moreover, in the present Example, the plastic mirror-shaped resin molded product 5 was formed by the insert molding method (FIGS. 8 to 14) using the direct molding method described above, using the sheet 10 infiltrated with metal fine particles. . In insert molding, polyphthalamide (Amodel AS-1566, manufactured by Solvay Advanced Polymers Co., Ltd.) as a molding resin was heated to 320 ° C. and injection-filled into the mold 73. Polyphthalamide is a polyamide-based resin and has high heat resistance and low expansion coefficient properties.

  Further, in this example, the nickel phosphorus plating film 3 was formed to a thickness of 1 μm on the surface of the resin molded product 5 by the above-described normal pressure electroless plating method containing alcohol (FIG. 15).

In this embodiment, an electrolytic Ni plating film containing a brightening agent having a leveling effect is formed on the nickel phosphorus plating film 3 with a thickness of 2 μm on the nickel phosphorus plating film 3 as a base film. The surface was smoothed. Further, Ni on the smoothed surface was substituted with Ag by substitution silver plating (Meltex, Alpha Star). The film thickness of Ag plating was 100 nm. Further, a protective film made of an organic (acrylic) -inorganic (SiO ₂ ) hybrid material (JSR Glassca) was formed to a thickness of 5 μm on the Ag plating film by dipping.

  Through the above processing, in this example, a plastic mirror was formed as the resin molded product 5 having the metal film 3. Since this plastic mirror is made of polyphthalamide resin, it has heat resistance and high dimensional accuracy, and the shape of the reflective film (3) can be maintained even in a high temperature environment. In addition, a smooth nylon 6 layer is formed on the surface of the resin molded product 5, and the reflective film (3) is formed on the surface without roughening the surface with an etching solution. A plastic mirror having a smooth and highly reliable reflecting surface was obtained.

  In addition, the absolute reflectance (regular reflection) at the center of the plastic mirror of this example was as high as 95 to 97% (measurement wavelength 550 nm) regardless of the thickness difference of the sheet 10. When the plastic mirror of this example was subjected to an environmental test for 100 hours in an environment of a temperature of 80 ° C. and a humidity of 95% RH, no swelling or white turbidity was observed in the plating film (3). Further, the decrease in reflectance before and after the environmental test was within 3%.

  In this example, 90 and 200 μm thick nylon 6 sheets 10 were prepared, and metal fine particles were applied to these sheets 10 using the batch method (FIGS. 2 and 3) using high-pressure carbon dioxide described above. Infiltrated.

  Further, in this embodiment, the box-shaped resin molded product 5 is obtained by the insert molding method using the above-described preform (FIGS. 5, 6, and 7) using the sheet 10 infiltrated with metal fine particles. Formed. In the insert molding, nylon 6 (with glass fiber 20%, Mitsubishi Engineering Plastics Novamid 1013GH20) and polycarbonate (with glass fiber 20%, Mitsubishi Engineering Plastics GS2020MR2) are used as molding resins, each at 250 ° C. The mold 73 was heated to 350 ° C. and injected into the mold 73. The surface of the resin molded product 5 formed by insert molding is closer to the surface roughness of the mirror surface of the mold 73 than the surface roughness of the original sheet 10, and is smoothed to improve the glossiness. This is because the high-temperature molten resin injected and filled into the mold 73 comes into contact with the sheet 10 in contact with the mold 73, the sheet 10 is melted by this contact, and then the sheet 10 together with the molten resin is molded into the mold 73. This is because it was solidified into a shape.

  Further, in this example, similarly to Example 1, the nickel phosphorus plating film 3 having a thickness of 1 μm is formed on the surface of the resin molded product 5 by the above-described alcohol-containing normal pressure electroless plating method (FIG. 15). did. Further, known decorative plating was performed. Specifically, electrolytic Cu plating containing a brightener is formed to a thickness of 40 μm, semi-bright electrolytic Ni plating is formed to a thickness of 10 μm, bright Ni plating is formed to a thickness of 10 μm, Cr plating was formed to a thickness of 0.5 μm. The present decorative plated molded article 5 has a gloss comparable to that of a plated article using ABS, although the molding resin is a material containing glass fibers and is difficult to obtain surface properties.

  And about the molded article 5 of a present Example, the heat shock test which repeats hold | maintaining in -40 degreeC environment for 1 hour, and hold | maintaining in 100 degreeC environment for 1 hour was done. As a result, in the molded product 5 of this example, even if the thickness of the sheet 10 used for insert molding was 90 μm or 200 μm, the metal film 3 did not swell and crack after the 20-cycle test.

  In addition, the molded product 5 of this example uses nylon 6 reinforced with glass fiber and polycarbonate as a molding resin. Thus, by using a combination of polycarbonate and nylon 6 whose thermal expansion coefficient is suppressed by glass fiber, it is caused by the difference between the thermal expansion coefficient of the metal film 3 and the thermal expansion coefficient of the resin, and at the time of thermal shock. The internal stress generated at the interface between the metal film 3 and the resin was suppressed, and peeling of the plating film 3 could be avoided.

  In the present example, a nylon 6 layer and a polypropylene layer (PP layer) were used in a batch method (FIGS. 2 and 3) using the above-described high-pressure carbon dioxide using a sheet 10 having a thickness of 120 μm. Metal fine particles were permeated into the sheet 10.

  Further, in this embodiment, a box-shaped resin is obtained by the insert molding method (FIGS. 5, 6, and 7) using the above-described preform method using the two-layer sheet 10 infiltrated with metal fine particles. Molded product 5 was formed. The sheet 10 was disposed on the mold 73 with the nylon 6 layer in contact with the mold 73. Polypropylene (Novatech MA3H manufactured by Nippon Polypro Co., Ltd.) was used as the molding resin. PP is a cheap and most versatile resin material, but it has excellent chemical resistance and low water absorption. Therefore, when the resin molded product 5 is formed by itself, it has high adhesion by electroless plating under normal pressure. The plating film 3 cannot be formed.

  Further, in this example, similarly to Example 2, the nickel phosphorus plating film 3 having a thickness of 1 μm is formed on the surface of the resin molded product 5 by the above-described alcohol-containing normal pressure electroless plating method (FIG. 15). Furthermore, well-known decorative plating was performed.

  And, according to ABS automotive parts plating standards, the molded product 5 of this example is held for 1 hour in an environment of −40 ° C. and held for 1 hour in an environment of 80 ° C. 3 Repeated heat cycle test was performed. As a result, in the molded product 5 of this example, the inserted sheet 10 and the plating film 3 did not peel or swell. For example, no peeling or swelling occurred at the edge portion of the inserted sheet 10.

  Further, according to the insert molding method of the present invention, the sheet 10 having the polyamide layer capable of forming the strong plating film 3 on the surface layer is insert-molded, and the PP layer on the back surface of the sheet 10 and the PP of the molding resin are formed. Since they can be integrated, the plating film 3 equivalent to the conventional ABS can be formed on the PP molded product 5 which is difficult and inexpensive to plate. In addition, partial plating with respect to the resin molded product 5 becomes possible, without performing the masking process etc. with respect to the resin molded product 5 by installing the sheet | seat 10 for plating with respect to the metal mold | die 73 partially.

  In this example, a sheet 10 made of nylon 6 into which metal fine particles were infiltrated was formed using the above-described extrusion method using high-pressure carbon dioxide (FIG. 4). The sheet 10 was formed to a thickness of 50 μm.

  Further, in this example, mirror-shaped resin molding was performed by the insert molding method (FIGS. 8 to 14) using the direct molding method described above as in Example 1, using the sheet 10 infiltrated with metal fine particles. Product 5 was formed.

  Further, in this embodiment, the nickel phosphorus plating film 3 is formed with a thickness of 1 μm on the surface of the resin molded product 5 by the above-described normal pressure electroless plating method (FIG. 15). The same plating film and protective film as in Example 1 were overlaid on top.

  In the same manner as in Example 1, the reflection characteristics before and after the high temperature and humidity environment test were evaluated. Even when the polyamide sheet 10 infiltrated with metal fine particles was formed by an extrusion method as in this example, it was confirmed that a plastic mirror excellent in weather resistance and reflection characteristics was obtained as in Example 1. .

  In this example, a sheet 10 made of nylon 6 having a thickness of 25 μm is prepared, and this sheet 10 is applied to the sheet 10 using the batch method (FIGS. 2 and 3) using high-pressure carbon dioxide as described in Example 1. Metal fine particles were infiltrated.

  Further, in this example, similarly to Example 1, the box-shaped resin molded product 5 was formed by the insert molding method (FIGS. 8 to 14) using the direct molding method using the high-pressure carbon dioxide described above. .

  Thereafter, in this embodiment, as shown in FIGS. 16 to 18, the sheet 10 is partially installed in the mold 73 so that the metal film 3 is partially formed on the surface of the resin molded product 5. In addition, the resin molded product 5 was irradiated with laser light so that the nylon 6 layer 6 was partially formed on the surface of the resin molded product 5.

  Specifically, first, the polyamide sheet 10 in which the metal fine particles are dispersed is cut into a rough pattern and fixed to the mold 73. The sheet 10 is molded with a width of the order of millimeters to centimeters by providing an adhesive layer to the mold 73 on the surface of the sheet 10 or providing a recess for fixing the sheet 10 on the surface of the mold 73. 73 can be fixed. In this embodiment, first, the sheet 10 cut so as to have a minimum line width of 2 cm is temporarily fixed to the fixing jig 81, and then the mold 73 is pressed against the mold 73. The sheet 10 was transferred to the mold 73 by vacuum suction from the vacuum suction groove 76.

  Thereafter, insert molding was performed using a polyphthalamide resin by the same molding method as in Example 1. Thereby, as shown in FIG. 16, the resin molded product 5 in which the polyamide sheet 10 is partially integrated on the surface of the molded product main body 5 made of polyphthalamide resin is obtained.

After that, as shown in FIG. 17, the sheet of polyphthalamide resin 10 on the surface of the resin molded product was irradiated with a CO ₂ laser beam 91 for laser drawing. Thereby, a portion of the polyphthalamide resin sheet 10 that has not been irradiated with laser light remains on the surface of the resin molded product 5. Further, the line width (pattern line width) of the remaining sheet was 0.4 mm.

  Next, in this example, the nickel phosphorus plating film 3 is formed on the surface of the resin molded product 5 with a thickness of 1 μm by the above-described alcohol-containing normal pressure electroless plating method, and further contains no alcohol. A metal film is formed with a thickness of 15 μm using an electroless nickel / copper alloy plating solution, a metal film is formed with a thickness of 5 μm using a nickel-phosphorous plating solution containing no alcohol, and A metal film having a thickness of 0.5 μm was formed by Au displacement plating. Thereby, as shown in FIG. 18, the metal film 3 is formed on the surface of the remaining resin sheet 10.

  Thereby, for example, an electric circuit pattern 2 as shown in FIG. 19 could be partially formed on the surface of the resin molded product 5. FIG. 19 shows the electric circuit pattern 2 in the state after nickel phosphorus plating in the series of plating processes described above.

  Further, when the resin molded product 5 of this example was annealed at a temperature of 260 ° C. for 10 minutes, no swelling or peeling was observed in the electric circuit pattern (selective plating portion) 2. Thus, since the resin molded product 5 of the present example can withstand the annealing process at a temperature of 260 ° C. for 10 minutes, there is no problem in hand reflow resistance.

  In this example, a nylon 6 sheet having a thickness of 250 and 300 μm was used, and the same batch method (FIGS. 2 and 3) and preform method (FIGS. 5, 6, and 7) as in Example 2. A resin molded product 5 having the metal film 3 was formed. Moreover, the glass fiber-containing nylon 6 of Example 2 was used for the molding resin used at the time of insert molding.

  Unlike the molded product 5 of Example 2, the surface of the resin molded product 5 formed by insert molding was equivalent to the surface property of the sheet 10. This is considered to be because the sheet 10 was not sufficiently melted at the time of insert molding because the thickness of the sheet 10 was increased, and as a result, the sheet 10 did not adhere to the mold 73. In particular, since polyamide is a crystalline resin and has a high melting point of 200 ° C. or higher, it is harder to be softened and melted than polycarbonate that softens above the glass transition temperature. As a result, the polyamide is difficult to be completely integrated with the resin of the sheet 10 at the time of injection molding. From this result, it can be seen that in order to bring the surface property of the molded product 5 close to the surface property of the mold 73, it is necessary to make the sheet 10 thinner as in the second embodiment.

  Further, in this example, similarly to Example 2, the nickel phosphorus plating film 3 having a thickness of 1 μm is formed on the surface of the resin molded product 5 by the above-described alcohol-containing normal pressure electroless plating method (FIG. 15). And well-known decorative plating was implemented.

  And when the heat shock test similar to Example 2 was done about the molded article 5 of the present Example, the plating film 3 swelled after several cycles. When the cross-sectional structure of the peeled portion was observed with an electron microscope, no peeling was observed at the interface between the sheet 10 and the plating film 3, and the polyamide resin portion inside the molded product 5 was stretched and broken. When the nylon 6 resin sheet 10 having a large linear expansion coefficient is thermally expanded, it is presumed that the polyamide resin portion cannot withstand thermal shock.

  Thus, in order to make use of the physical properties of the base resin material and to achieve both surface smoothness of the molded product 5, the thickness of the polyamide sheet 10 of the present invention is preferably less than 250 μm. When the thickness of the polyamide sheet 10 is 10 μm or less, it becomes difficult to form the sheet 10. Based on these results, a desirable sheet thickness is 10 to 200 μm.

  In this example, a resin molded product 5 having a metal film was obtained in the same manner as in Example 2 except that 1-ethoxy-2-propanol was used as the alcohol mixed with the electroless plating solution.

  And the molded product 5 of a present Example was strong to heat shock similarly to the molded product of Example 2, and the surface property was favorable.

  In this example, resin molding having a metal film 3 in the same manner as in Example 1 except that polyphthalamide (nylon 6T), which is aromatic nylon, is used as the material of the sheet 10 and the sheet thickness is 100 μm. Product 5 was obtained.

  And the molded product 5 of a present Example obtained the reflecting film excellent in adhesiveness and a weather resistance similarly to the molded product 5 of Example 1. FIG.

[Comparative Example 1]
In this comparative example, an attempt was made to obtain the resin molded product 5 having the metal film 3 by the same method as in Example 2 except that the thickness of the nylon 6 sheet 10 was 25, 40 μm.

  However, a part of the preformed sheet 10 is damaged, and the sheet 10 cannot be properly fixed to the mold 73 during the filling and curing of the molding resin. As described above, when the thin sheet 10 of 40 μm or less was preformed, the sheet 10 could not be properly fixed to the mold 73.

  In Examples 4 and 5, a nylon 10 sheet 10 having a thickness of 25, 50 μm was used, but the sheet 10 could be fixed to the mold by a direct molding method. The range of the sheet thickness suitable for the direct molding method is arbitrary because the strength varies depending on the resin material, and the stretch amount of the sheet varies depending on the shape, but in the case of nylon 6, the thickness of the sheet 10 is 10 to 90 μm. At some point, the sheet 10 could be properly fixed to the mold 73 by a direct molding method. In the case of nylon 6, when the film thickness of the sheet 10 is 25 μm to 40 μm, the sheet could not be formed into a shape that can be inserted into an injection mold by the preform method.

[Comparative Example 2]
In this comparative example, the thickness of the sheet 10 was 200 μm, and the metal film 3 was formed in the same manner as in Example 1 except that no alcohol was included in the electroless plating solution used for electroless plating under normal pressure. A resin molded product 5 having the following was obtained.

  And when the heat shock test was done like Example 2, in the plating molded product 5 of this comparative example, the plating film 3 swelled by one cycle of heat shock. From this, it was found that in order to improve the adhesion of the metal film 3 formed by electroless plating under normal pressure, it is necessary to add alcohol to the electroless plating solution.

[Comparative Example 3]
In this comparative example, a resin molded product 5 having a metal film 3 in the same manner as in Example 2 except that a polycarbonate sheet having a thickness of 100 μm is used as the resin sheet 10 and a polycarbonate resin containing glass fibers is used as the molding resin. Got.

  And when the heat shock test was done like Example 2, in the plating molded product 5 of this comparative example, a part of plating film 3 peeled by the heat shock of 1 cycle. When examined in detail, it was found that the plating film 3 did not grow from the inside of the resin molded product 5. This is thought to be because the resin film having a low water absorption was used as the material of the sheet 5, so that the plating film 3 could not penetrate into the resin molded product 5 even when electroless plating containing alcohol was performed. It is done.

  In the method for producing a resin molded article having a metal film according to the present invention, a metal film having high adhesion for general purposes regardless of the material of the resin molded article by an inexpensive treatment using an electroless plating solution at normal pressure. Can be formed into a resin molded product. Further, in the present invention, a metal film can be formed in a desired pattern on the resin molded product. Therefore, the manufacturing method of the present invention is suitable for molding a headlamp unit of an automobile and its reflector that require heat resistance and durability, when molding a mirror of an optical component that requires high reflectivity characteristics, When molding a molded product requiring durability such as plating, it can be used for molding a MID or an electromagnetic shield molded body for forming an electric circuit on the surface of a resin molded product.

FIG. 1 is a process diagram showing a method for producing a resin molded product having a metal film. FIG. 2 is a schematic configuration diagram of a batch apparatus for infiltrating metal fine particles into a resin sheet. FIG. 3 is a perspective view showing a resin sheet accommodated in the high-pressure container in FIG. 1. FIG. 4 is a schematic configuration diagram of an extrusion molding apparatus for forming a resin sheet infiltrated with metal fine particles. FIG. 5 is a partial cross-sectional view of the injection molding apparatus in a state where a resin sheet is preformed on a mold. FIG. 6 is a partial cross-sectional view of the injection molding apparatus in a state where the molding resin is injected and filled in the mold. 7A to 7D are explanatory views of the preform process. FIG. 8 is an explanatory diagram of a process of directly forming a resin sheet using an immobilizing jig. (A) is a positioning state, and (B) is a state during molding. FIG. 9 is a partial cross-sectional view of the injection molding apparatus in a state where the fixing jig to which the resin sheet is stuck is positioned on the movable mold. FIG. 10 is a partial cross-sectional view of the injection molding apparatus in a state where the resin sheet is sandwiched between the fixing jig and the movable mold. FIG. 11 is a partial cross-sectional view of the injection molding apparatus in a state where the resin sheet is in close contact with the movable mold. FIG. 12 is a partial cross-sectional view of the injection molding apparatus in a state where a molding resin is injected and filled into a mold. FIG. 13 is a cross-sectional view of a resin molded product formed by an injection molding apparatus. FIG. 14 is a cross-sectional view of a reflector-shaped resin molded product. FIG. 15 is a cross-sectional view of a reflector-shaped resin molded product having a metal film. FIG. 16 is a partial cross-sectional view of a resin molded product in which a resin sheet is partially disposed. FIG. 17 is a partial cross-sectional view of a resin molded product in a state where laser drawing is performed on a resin molded product in which a resin sheet is partially disposed. FIG. 18 is a partial cross-sectional view of a resin molded product on which a metal film is formed. FIG. 19 is a partially enlarged view of a resin molded product on which an electric circuit pattern is formed using a metal film.

Explanation of symbols

3 Metal Film 5 Resin Molded Product 10 Resin Sheet 11 High Pressure Container 73 Mold (Mold for Injection Molding)
79 Mold (mold for preform)
91 Laser light

Claims (13)

A method for producing a resin molded product having a metal film,
Place at least one surface of a resin sheet formed of a polyamide resin in which metal fine particles are dispersed in a mold for molding the resin molded product in a state where the polyamide resin is in contact with the mold. To do
Filling the mold in which the resin sheet is installed with a molten resin, and molding the resin molded product formed by integrating the resin sheet and the molten resin;
Immersing the resin molded article in an electroless plating solution containing alcohol under normal pressure.   The manufacturing method according to claim 1, wherein the resin sheet has a thickness of 10 to 200 μm. The resin sheet has a thickness of 10 to 150 μm, and
Before filling the mold with the molten resin, the resin sheet placed in the mold is brought into close contact with the mold by at least one of heating, pressurization, and vacuum suction. The manufacturing method of Claim 1 or 2 including this.   The manufacturing method according to claim 3, wherein heating the resin sheet installed in the mold includes applying hot air to the resin sheet installed in the mold. The resin sheet has a thickness of 50 to 200 μm, and
Installing the resin sheet in the mold,
Molding the resin sheet in accordance with the shape of the mold before installing in the mold;
The manufacturing method according to claim 1, further comprising: placing the resin sheet molded in accordance with the shape of the mold in the mold for injection molding. Installing the resin sheet in the mold,
The manufacturing method according to any one of claims 1 to 5, comprising partially installing the resin sheet on a part of a molding surface of the mold.   Furthermore, before the resin molded product is immersed in the electroless plating solution, the resin molded product is irradiated with laser light to partially remove the polyamide-based resin from the resin molded product. Item 7. The method according to any one of Items 1 to 6.   Furthermore, before the resin molded product is immersed in the electroless plating solution containing the alcohol under normal pressure, the resin molded product having the polyamide resin on the surface thereof is immersed in an aqueous solution in which a reducing agent is dissolved. Item 8. The method according to any one of Items 1 to 7.   The manufacturing method according to any one of claims 1 to 8, wherein the polyamide-based resin is 6 nylon or 66 nylon.   The other surface of the resin sheet is formed of a resin that is different from the polyamide-based resin and that is melt-bonded to the molten resin filled in the mold. The manufacturing method according to one item.   The method according to claim 1, wherein the metal fine particles are at least one fine particle selected from a palladium complex, a modified product of a palladium complex, and palladium metal fine particles.   Further, a resin sheet having at least one surface formed from a polyamide-based resin is formed into a long shape by extrusion, the long resin sheet is wound so that the surface is exposed, and is accommodated in a high-pressure container. By introducing high-pressure carbon dioxide in which the metal complex that forms the metal fine particles is dissolved into the high-pressure vessel, a resin sheet in which at least one surface is formed from a polyamide-based resin in which the metal fine particles are dispersed is generated. The manufacturing method according to claim 1, further comprising:   Further, when a resin sheet having at least one surface formed of a polyamide-based resin is molded by extrusion molding, high-pressure carbon dioxide in which the metal complex that is the source of the metal fine particles is dissolved is used as a molten resin or mold before molding. 12. The method according to claim 1, further comprising: generating a resin sheet in which at least one surface is formed of a polyamide-based resin in which the metal fine particles are dispersed, by contacting with the resin inside. Production method.

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