JP2009113266A - Method for modifying surface of plastic molded body, method for forming metal film including the same, and plastic component thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface modifying method for roughening the surface of a plastic molded body to obtain an excellent anchoring effect even if the plastic molded body has a complicated three-dimensional shape, a method for forming a metal film including the same, and a plastic component thereof. <P>SOLUTION: The surface modifying method for the plastic molded body 2 formed by melting and injecting the plastic into a mold comprises a step for bringing the molten plastic 120 into contact with high-pressure carbon dioxide dissolved with a fluorine compound, a step for injecting the molten plastic 120 contected with the high-pressure carbon dioxide into the mold 101 and molding it, and a step for dissolving the fluorine compound impregnated in the surface part of the plastic molded body 2 obtained in the molding step with the high-pressure carbon dioxide and for removing the fluorine compound from the surface part of the plastic molded body 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for modifying a surface of a plastic molded body, a method for forming a metal film including the method, and a plastic part.

  The plastic molded body is used as a part of an electronic device, for example. As a means for forming a metal film on the surface of a plastic molded body, an electroless plating method is currently widely used. The manufacturing process from molding of plastic molded body to electroless plating is somewhat different depending on the material of molded body, etc., but generally resin molding, degreasing of molded body, etching, neutralization and wetting, catalyst application, catalyst activation, The electroless plating process is performed in this order.

  In the etching step in the electroless plating process, the surface of the plastic molded body is physically roughened using a chromic acid solution or an alkali metal hydroxide solution. By roughening the surface of the plastic molded body, an anchoring effect is generated between the molded body and the plated film, and the adhesion of the plated film to the molded body is ensured.

  However, since the etching solution requires post-treatment such as neutralization at the time of disposal, it contributes to high cost. Further, chromic acid solution and alkali metal hydroxide solution are highly toxic and handling thereof is complicated.

  An electroless plating method using carbon dioxide in a supercritical state (hereinafter also referred to as supercritical carbon dioxide) has been proposed as a new metal film forming method that replaces the electroless plating method using an etching solution (for example, Non-Patent Document 1). According to the method described in Non-Patent Document 1, first, an organometallic complex is dissolved in supercritical carbon dioxide, and the supercritical carbon dioxide is brought into contact with a molded body of various polymers. Inject (infiltrate) the organometallic complex. Next, the organic metal complex is reduced by heat treatment or chemical reduction treatment on the polymer molded body into which the organometallic complex has penetrated. Thereby, metal fine particles are deposited on the surface of the polymer molded body.

  In the electroless plating method using this organometallic complex and supercritical carbon dioxide, an etching solution is not used, so that the waste solution treatment is naturally not necessary. Further, the deposition of the metal fine particles enables the electroless plating of the polymer molded body.

  In addition, a plating pretreatment process using a photocatalyst has been proposed as a process for obtaining a good anchoring effect by appropriately roughening the plastic surface (see, for example, Patent Document 1). In patent document 1, after apply | coating the titanium oxide as a photocatalyst to the surface of a plastic molding, it irradiates with an ultraviolet-ray. Thereby, fine unevenness | corrugation is formed in the surface of a plastic molding. Due to the anchoring effect due to the fine irregularities, it is possible to form a plating film on the plastic molded body.

  In addition to this, the method of making a resin composition such as a plastic molded body porous is limited to a polyimide resin, but a method using supercritical carbon dioxide has been proposed (for example, patents). Reference 2). In Patent Document 2, a polyamic acid resin which is a precursor of polyimide and a photosensitive resin composition containing a dispersible compound dispersible therein are removed by using a supercritical carbon dioxide to remove the dispersible compound. The formed polyamic acid resin is formed. Further, in Patent Document 2, a conductive layer is further formed on a porous polyamic acid resin. Patent Document 2 does not describe the physical shape on the outermost surface of the resin after the dispersible compound is removed using supercritical carbon dioxide. Further, Patent Document 2 does not describe the adhesion between the resin and the conductive layer.

  In addition, it is known that a fluorine compound dissolves in supercritical carbon dioxide or carbon dioxide in a study of compatibilizing an aqueous solvent and supercritical carbon dioxide (for example, Non-Patent Document 2 and Patent Document 3).

JP-A-2005-85900 JP 2001-215701 A Japanese Patent Application No. 2002-171609 Teruo Hori, “Latest Application Technology of Supercritical Fluids”, NTS Publishing, p. 250-255 (2004) Takafumi Nagai "Functional Materials January 2007 Issue Vol.27 No.1" CMC Publishing Co., Ltd. p27-p36

  As a result of intensive studies by the present inventors on the surface modification process using supercritical carbon dioxide described in Non-Patent Document 1, it has been found that there are the following problems. That is, in the surface modification process using supercritical carbon dioxide of Non-Patent Document 1, there is no process for physically roughening the plastic surface. Therefore, the smoothness of the surface after the surface modification according to Non-Patent Document 1 is good, but the anchoring effect cannot be obtained at the interface between the plating film and the plastic molded body. The adhesion of the plating film to the plastic molded body is basically not high.

  When a plating film is formed on the plastic surface by the method of Non-Patent Document 1 where the anchoring effect cannot be obtained, the plating film is ensured to be adhered by the organometallic complex on the plastic surface. Therefore, the adhesion of the plating film is strongly influenced by the reducing property of the organometallic complex and the density and aggregation state of the metal fine particles on the plastic surface resulting therefrom. Then, when considering the mass production process by the method of Non-Patent Document 1, it is expected that it is extremely difficult to appropriately control all these conditions and to maintain the conditions.

  As a result, when the plating film is formed by the method of Non-Patent Document 1, the adhesion is not basically high and is expected to vary greatly between products.

  In addition, in the photocatalytic process using titanium oxide described in Patent Document 1, it is necessary to irradiate the plastic surface with ultraviolet rays to generate a photocatalytic reaction in order to roughen the plastic surface. For this reason, the method of Patent Document 1 is considered suitable for a two-dimensionally shaped molded body (for example, a film-shaped molded body) capable of uniform irradiation with ultraviolet rays, but has a complicated three-dimensional shape. It is difficult to uniformly irradiate the surface of the molded body with ultraviolet rays, which is considered unsuitable. For example, when a molded object has a hole, it is very difficult to irradiate a uniform ultraviolet-ray with respect to the hole and the outer surface of a molded object. Moreover, since the reaction time of the photocatalyst is as long as several tens of minutes, this becomes one of the obstruction factors of the mass production process.

  An object of the present invention is to provide a surface modification method capable of roughening the surface with a good anchoring effect even if the plastic molded body has a complicated three-dimensional shape. In addition, the present invention includes this surface modification method, and even if the plastic molded body has a complicated three-dimensional shape, it is possible to form a highly adhesive metal film having a good anchoring effect. It is an object of the present invention to provide a method for forming a metal film and a plastic part formed by the method.

  According to a first aspect of the present invention, there is provided a method for modifying the surface of a plastic molded article formed by melting a plastic and injecting it into a molding die, wherein the high pressure dioxide in which a fluorine compound is dissolved in the molten plastic. A step of contacting carbon, a step of injecting a molten plastic contacted with high-pressure carbon dioxide into a molding die, molding, and a fluorine compound impregnated on the surface portion of the plastic molding obtained in the molding step with high-pressure dioxide. And a step of removing the fluorine compound from the surface portion of the plastic molded body by dissolving with carbon.

  Even if the fluorine compound is a polymer, it has a property of being well dissolved in high-pressure carbon dioxide. Therefore, first, the fluorine compound can be satisfactorily dissolved in the high-pressure carbon dioxide brought into contact with the molten plastic. Next, by bringing such high-pressure carbon dioxide into contact with the plastic, a plastic molded body in which the fluorine compound is impregnated on the surface with the high-pressure carbon dioxide is produced. Further, the impregnated fluorine compound is dissolved by contacting the compact with high-pressure carbon dioxide. As a result, a large number of nano-order fine holes can be formed in the plastic molded body. Even if the plastic molded body has a complicated three-dimensional shape, it can have a surface roughness that can provide a good anchoring effect. In addition, this method can be used for surface modification of various types of plastics. Moreover, the fluorine compound also functions effectively as a release agent from the molding die.

  In the present invention, the high-pressure carbon dioxide in which the fluorine compound is dissolved is brought into contact with the plastic in a molten state, whereby the fluorine compound is dispersed in the plastic molded body. Therefore, according to the present invention, fine holes having a size that can provide a good anchoring effect can be formed on the plastic surface with high density and even dispersion. On the other hand, surface roughening is possible by bringing high-pressure carbon dioxide in which a fluorine compound is dissolved into contact with the molded plastic surface, but when the molecular weight of the fluorine compound is particularly large, the surface portion of the plastic ( It is difficult to secure a free volume for the fluorine compound to permeate in the vicinity of the surface). Therefore, compared with the case where high-pressure carbon dioxide in which a fluorine compound is dissolved is brought into contact after molding as described above, it is much shorter in the case where high-pressure carbon dioxide in which a fluorine compound is dissolved is brought into contact with a molten plastic. Thus, fine holes of a size that can provide a good anchoring effect can be formed on the plastic surface with high density and uniform dispersion.

  The “high pressure carbon dioxide” referred to in the present invention includes not only supercritical carbon dioxide but also high pressure liquid carbon dioxide (liquid) and high pressure carbon dioxide. In addition to high-pressure carbon dioxide, mediums that dissolve fluorine compounds to some extent include air, water, butane, pentane, methanol, etc., but high-pressure carbon dioxide has a solubility in organic materials comparable to n-hexane and is non-polluting. Moreover, it is optimal because of its high affinity for plastic. Moreover, in this invention, in order to improve the solubility of the fluorine compound with respect to a high pressure carbon dioxide, you may mix small amounts of organic solvents, such as ethanol, as an entrainer with respect to a high pressure carbon dioxide.

  In the first aspect of the present invention, the high-pressure carbon dioxide in which the fluorine compound is dissolved may come into contact with a portion first injected into a molding die for molten plastic. Alternatively, the high-pressure carbon dioxide in which the fluorine compound is dissolved may be introduced into the flow front portion of the heating cylinder that accommodates the molten plastic that is injected into the molding die.

  When high-pressure carbon dioxide is brought into contact with the molten plastic in this way, first, the molten plastic in the flow front part infiltrated with the fluorine compound is injected, and then the molten plastic almost not infiltrated with the fluorine compound is injected and filled into the mold. Will be. When molten plastic in the flow front part infiltrated with a fluorine compound is injected, the molten plastic in the flow front part is pulled to the mold surface by the fountain flow phenomenon (fountain effect) of the flowing resin in the mold. A surface layer (skin layer) is formed in contact with the mold. Therefore, in these embodiments, a plastic molded body comprising a skin layer in which a fluorine compound is dispersed and a core layer in which the fluorine compound is hardly dispersed is provided. Regardless of the material of the plastic molded body, the fluorine compound is segregated on the surface portion of the plastic molded body and is uniformly dispersed at a high density on the surface portion.

  In addition, the fluorine compound has a property of rising to the surface side closer to the mold of the skin layer. Therefore, many fluorine compounds can be unevenly distributed on the outermost surface of the plastic molded body.

  Therefore, by dissolving with high-pressure carbon dioxide after molding, more fluorine compound can be dissolved from the plastic molded body, and more fine holes can be formed in the plastic molded body. With the minimum necessary addition amount, a large number of fine holes can be efficiently formed in the plastic molded body. It is possible to reduce the fluorine compound remaining in the plastic molded body after being dissolved with high-pressure carbon dioxide, and to effectively use the fluorine compound for the formation of unevenness.

  According to a second aspect of the present invention, there is provided a method for modifying the surface of a plastic molded article formed by melting plastic and injecting it into a molding die, wherein plastic pellets in which a fluorine compound is dispersed are obtained. A step of melting, a step of injecting the melted pellets into a molding die, a step of molding, and a fluorine compound impregnated on the surface of the plastic molded body obtained by injection molding is dissolved in high-pressure carbon dioxide to produce a plastic Removing the fluorine compound from the surface portion of the molded body.

  In the surface modification method of the present invention, a number of nano-order fine holes can be formed in a plastic molded body formed by injection molding using pellets. Even if the plastic molded body has a complicated three-dimensional shape, it can have a surface roughness that can provide an anchoring effect. The present invention can be used for surface modification of various types of plastics. Moreover, since the apparatus used for injection molding does not need to use high-pressure carbon dioxide, a general-purpose injection molding apparatus can be used as it is. Moreover, the fluorine compound also functions effectively as a release agent from the molding die.

  According to a third aspect of the present invention, there is provided a method for modifying the surface of a plastic molded body formed by extruding a plastic material from an extrusion mold, wherein the high pressure carbon dioxide in which a fluorine compound is dissolved is brought into contact with the plastic material. A step of molding a plastic material in contact with high-pressure carbon dioxide by extruding it from an extrusion mold, and dissolving a fluorine compound impregnated on a surface of a plastic molded body obtained by molding with high-pressure carbon dioxide, Removing the fluorine compound from the surface portion of the plastic molded body.

  In the surface modification method of the present invention, a large number of nano-order fine holes can be formed in a plastic molded body formed by extrusion molding. Even if the plastic molded body has a complicated three-dimensional shape, it can have a surface roughness that provides an anchoring effect. The present invention can be used for surface modification of various types of plastics. Moreover, the fluorine compound also functions effectively as a release agent from the molding die. The high-pressure carbon dioxide in which the fluorine compound is dissolved may be in contact with the molten plastic between the heating cylinder and the extrusion die.

  In addition, since high-pressure carbon dioxide in which a fluorine compound is dissolved is brought into contact with the plastic in a molten state, fine holes having a size capable of obtaining an anchoring effect are formed with high density and uniform dispersion on the plastic surface. Can do. In contrast, when high-pressure carbon dioxide in which a fluorine compound is dissolved is brought into contact with the plastic surface after molding, especially when the molecular weight of the fluorine compound is large, the surface portion of the plastic (in the vicinity of the surface) It is difficult to secure a free volume for the penetration of the fluorine compound. Therefore, compared to the case where high-pressure carbon dioxide in which a fluorine compound is dissolved after contact is formed in this way, it is better to contact high-pressure carbon dioxide in which a fluorine compound is dissolved in a molten plastic in a very short time. Fine holes having such a size as to obtain an anchoring effect can be formed on the plastic surface with high density and uniform dispersion.

  According to a fourth aspect of the present invention, there is provided a method for modifying a surface of a plastic molded body formed by extruding a plastic material from an extrusion die, the step of heating plastic pellets in which a fluorine compound is dispersed; , A step of extruding the heated plastic from the extrusion mold and molding the fluorine compound impregnated in the surface portion of the plastic molded body obtained by molding with high-pressure carbon dioxide, and fluorine from the surface portion of the plastic molded body Removing the compound, and a method for modifying the surface is provided.

  In the surface modification method of the present invention, a number of nano-order fine holes can be formed in a plastic molded body formed by extrusion molding using pellets. Even if the plastic molded body has a complicated three-dimensional shape, it can have a surface roughness that can provide an anchoring effect. The present invention can be used for surface modification of various types of plastics. Since the apparatus used for extrusion does not need to use high-pressure carbon dioxide, a general-purpose extrusion apparatus can be used as it is.

  In the first to fourth aspects of the present invention, the plastic may be a thermoplastic resin. Examples of the thermoplastic resin include polycarbonate, polymethyl methacrylate, polyetherimide, polymethylpentene, amorphous polyolefin, polytetrafluoroethylene, liquid crystal polymer, styrene resin, polymethylpentene, polyacetal, polyphenylene sulfide (PPS), Examples include polyethyl ether ketone and cycloolefin polymer. Moreover, what mixed several types of materials as a thermoplastic resin, the polymer alloy which has these as a main component, or the thing which mix | blended various fillers with these may be sufficient. And the surface of the plastic molding by these various thermoplastic resins can be made into desired surface roughness by combining a high pressure carbon dioxide and a fluorine compound.

  In the first to fourth aspects of the present invention, the pressure of the high-pressure carbon dioxide when the fluorine compound impregnated on the surface portion of the plastic molded body is dissolved with high-pressure carbon dioxide is 5 MPa to 25 MPa. There may be. The solubility of fluorine compounds in high-pressure carbon dioxide increases with increasing pressure. When the pressure is 5 MPa or less, the solubility of the fluorine compound becomes extremely low, and the penetration effect of the fluorine compound on the surface of the plastic does not appear. Further, when the pressure becomes 25 MPa or more, the permeability of high-pressure carbon dioxide to the plastic becomes too high, and it becomes difficult to prevent foaming from occurring in the plastic molded body.

  In the first to fourth aspects of the present invention, the boiling point of the fluorine compound may be 150 ° C. or higher. In this case, since the boiling point of the fluorine compound is high, the fluorine compound is hardly thermally decomposed in the plastic melted by heating for molding. Therefore, the fluorine compound dispersed before molding remains effectively in the molded plastic molded body, and the fluorine compound is melted with high-pressure carbon dioxide to form a desired amount of fine holes in the plastic molded body. Can do. A desired surface roughness can be obtained by adjusting the amount of the fluorine compound, and variations in the surface roughness can be suppressed.

  In addition, by using a fluorine compound having a boiling point of 200 ° C. or higher, even if a high melting point material such as polyphenylene sulfide (PPS) is used as the plastic, the fluorine compound is hardly decomposed in the molding machine, and the fluorine compound is added to the plastic molding. Can be dispersed in high density and uniformly. By using a fluorine compound having a boiling point of 200 ° C. or higher, the fluorine compound can be uniformly and uniformly dispersed in the plastic molding without selecting a plastic material.

  In the first to fourth aspects of the present invention, the molecular weight of the fluorine compound may be 500 to 15000. Unlike polyethylene glycol or the like, the fluorine compound can be dissolved in high-pressure carbon dioxide even if it is a polymer. Moreover, when the molecular weight of the fluorine compound is 500 or more, the fluorine compound segregates (bleeds out) on the surface of the plastic molded body during injection molding or extrusion molding. The fluorine compound penetrates into the vicinity of the plastic surface in a cluster form of several tens to several hundreds of nanometers. Therefore, the fluorine compound segregated on the surface in the melting treatment of the fluorine compound after molding is melted, thereby forming a fine hole of a desired large size, and a desired surface roughness that provides a high anchoring effect is obtained. Obtainable. Submicron to nano-order fine holes are formed on the surface of the plastic molding after the fluorine compound removal treatment. By effectively utilizing a high molecular fluorine compound, it is possible to obtain a desired surface roughness that provides a high anchoring effect.

  On the other hand, when the molecular weight of the fluorine compound exceeds 15000, the solubility in high-pressure carbon dioxide is lowered, and the compatibility with molten plastic is lowered. In addition, the weight of the molecular weight makes it difficult for the fluorine compound to float on the plastic surface during molding.

  Therefore, when the molecular weight of the fluorine compound is 500 to 15000, the fluorine compound is segregated on the surface portion of the plastic molded body with good solubility, but is uniformly dispersed throughout the surface portion. In addition, after the molding, the fluorine compound having a relatively large molecular weight is dissolved, so that the surface of the plastic molded body is formed with large fine holes that can provide a high anchoring effect as a whole, and can be used for metal film plating. Suitable surface roughness.

In addition, examples of the fluorine compound having good solubility in high-pressure carbon dioxide and satisfying the above-described molecular weight and boiling point include, for example, Perfluoro-2,5,8,11,14-pentamethyl represented by the following chemical formula 1. -3,6,9,12,15-pentaoxaoctadecanoyl fluoride (molecular formula: C ₁₈ F ₃₆ O ₆ (manufactured by Synquest Laboratory, molecular weight: 996.2, boiling point: 235 ° C.), perfluorotripentylamine (molecular formula: C ₁₅ F ₃₃ N (manufactured by Synquest Laboratory, molecular weight: 821.1, boiling point: 220 ° C.).

  As other fluorine compounds, Perfluoro-2,5,8-trimethyl-3,6,9-trioxadodecanoic acid, methyl ester (molecular weight: 676, boiling point: 196 ° C.), perfluorooctadecanoic acid (molecular weight: 915, boiling point: 235). ° C), Perfluoro (tetradecahydrophenanthrene) (molecular weight: 624, boiling point: 215 ° C), SpectraSynQ1621 (manufactured by Synquest Laboratory, molecular weight: 2120, boiling point: 220 ° C), 1H, 1H-Perfluoro-1-octadecanol (molecular weight: 900, Boiling point: 211 ° C), Hecakis (1H, 1H, 5H-octafluoropentoxy) phosphazene (molecular weight: 1521, boiling point: 207 ° C), 1,2-Bis (dipentafluorophenylphosphino) ethane (molecular weight: 758, boiling point: 190 ° C), Perfluorododecanoic acid (Molecular weight: 614, Boiling point: 245 ° C), Perfluoro-2,5,8,11-tetramethyl-3,6,9,12-tetraoxapentadecanoyl fluoride (Molecular weight: 830, Boiling point: 203 ° C), Perfluorohexadecanoic acid (Molecular weight: 814) , Boiling point: 211 ° C), Perfluoro-1,10 -decanedicarboxylic acid (molecular weight: 610, boiling point: 240 ° C.) and the like.

  Examples of the fluorine compound having a boiling point of less than 200 ° C. and a molecular weight of less than 500 include, for example, 1H, 1H-Perfluoro (2,5-dimethyl-3,6-dioxanonan-1-ol) (molecular weight: 482.1 , Boiling point: 155 ° C).

  According to a fifth aspect of the present invention, there is provided a method for forming a metal film on a plastic molded body formed by the surface modification method according to any one of the first to fourth aspects described above. Thus, there is provided a method for forming a metal film, comprising the step of forming a metal film on the surface of the plastic molded body after removing the fluorine compound.

  In the method for forming a metal film of the present invention, the surface of the plastic molded body has a surface roughness suitable for plating of a metal film that can provide an anchoring effect, so that the plastic molded body has an anchoring effect. A metal film with good adhesion can be formed.

  In addition, since the fine holes formed on the surface of the plastic molded body are sub-micron to nano-order, the surface of the metal film has excellent smoothness (surface roughness is suppressed) and excellent electrical characteristics. It becomes. Then, by adjusting the density of the fine holes formed on the surface of the plastic, the electrical characteristics such as the dielectric constant and dielectric loss tangent of the plastic, and the optical characteristics such as the reduction of the refractive index can be made into desired characteristics. Further, if the density of the fine holes formed on the surface of the plastic can be adjusted for each part, the optical characteristics can be varied as a whole, and it can be used as a reflection plate by irregular reflection. .

  According to a sixth aspect of the present invention, in the surface modification method according to any one of the first to fourth aspects described above, the fluorine impregnated in the surface portion of the plastic molded body There is provided a method for forming a metal film characterized in that a metal film is formed on the surface of a plastic molded body by dissolving a plating solution in high-pressure carbon dioxide for dissolving a compound.

  In the present invention, the metal film plating step can be integrated with the step of removing the fluorine compound from the plastic molded body. A metal film can be formed on a plastic molded body whose surface has been modified without adding a metal film plating step to the surface modification method. Plating can be performed before dirt or the like adheres to the surface after removing the fluorine compound. Therefore, it is possible to form a metal film with excellent smoothness and adhesion due to the anchoring effect due to the fine unevenness of submicron to nano-order size formed on the surface of the plastic and the merit of scale due to the expansion of the surface area. . Further, as described above, since the surface modification method of the present invention can form fine irregularities on the surface of various types of plastics, the metal film formation method of the present invention can smooth the surfaces of various types of plastics. A metal film having excellent properties and adhesion can be formed.

  In the fifth aspect or the sixth aspect of the present invention, the method further includes the step of dispersing the plating catalyst nucleus in the plastic molded body before forming the metal film, and the metal film may be grown from the plating catalyst nucleus. Good. As a result, the metal film is formed not only to enter a large number of fine holes formed on the surface of the plastic molded body, but also to grow from the plating catalyst nucleus in the plastic molded body. Therefore, as the anchoring effect of the metal film, it is possible to obtain more than that obtained by simply forming the metal film into the fine holes. The metal film has excellent weather resistance. As the plating catalyst nucleus, for example, metal fine particles such as Ni, Pd, Pt, and Cu may be used.

  In the fifth aspect or the sixth aspect of the present invention, further, before the metal film is formed by bringing the high-pressure carbon dioxide in which the plating catalyst core is melted into contact with the plastic molded body from which the fluorine compound has been removed. The plating catalyst core may be dispersed in the plastic molded body. Thereby, the plating catalyst core can be dispersed in the plastic molded body. Moreover, the plating catalyst nuclei are substantially uniformly dispersed on the surface of the plastic molding by bringing the plating catalyst nuclei into contact with the high-pressure carbon dioxide.

  In the fifth or sixth aspect of the present invention, a metal film is formed by further dissolving the plating catalyst nucleus in high-pressure carbon dioxide that is brought into contact with the molten plastic in order to disperse the fluorine compound in the plastic molded body. The plating catalyst nuclei may be dispersed in the plastic molded body before performing. Thereby, a plating catalyst nucleus can be disperse | distributed with a fluorine compound with respect to a molten plastic. The plating catalyst core can be dispersed in the plastic molded body without adding an independent step for dispersing the plating catalyst core to the surface modification step.

  In particular, in the combination with the sixth aspect, the plating catalyst nucleus is dispersed in the molten plastic together with the fluorine compound, and the plating is grown in the step of removing the fluorine compound from the molded plastic molded body. The plating process can be completed by the same number of steps as the surface modification process of the plastic molded body.

  In the fifth aspect or the sixth aspect of the present invention, the plating catalyst nucleus may be a metal complex containing fluorine. Thereby, a metal complex becomes easy to segregate on the plastic surface after a shaping | molding.

  According to a seventh aspect of the present invention, there is provided a plastic part having a porous plastic molded body in which a fluorine compound is dispersed inside and a plurality of fine holes are formed in the surface portion. Is provided. In the seventh aspect of the present invention, plating catalyst nuclei may be dispersed inside the plastic molded body. Further, in the seventh aspect of the present invention, the micropores may have a size from submicron to nano-order. Moreover, in the 7th aspect of this invention, you may have further the metal film formed in a fine hole on the surface of a plastic molding. In the seventh aspect of the present invention, the surface roughness of the metal film may be nano-order.

  In the plastic part of the present invention, a metal film having high adhesion to a plastic molded body is formed by an anchoring effect by entering a plurality of fine holes formed in the surface portion with a size of sub-micron to nano-order. be able to. In particular, when plating catalyst nuclei are dispersed inside, an anchoring effect by growing from the plating catalyst nuclei can be obtained, and a metal film having higher adhesion can be formed. This metal film can be formed by the metal film formation method of the fifth aspect or the metal film formation method of the sixth aspect described above.

  As described above, in the surface modification method of the present invention, even if the plastic molded body has a complicated three-dimensional shape, it can be modified to a surface roughness that provides a good anchoring effect. Further, in the metal film forming method including this surface modification method, even if the plastic molded body has a complicated three-dimensional shape, a metal film having an anchoring effect and good adhesion can be formed. . And the plastic component which has such a metal film with good adhesiveness can be obtained.

  In addition, in these methods, by combining a fluorine compound and high-pressure carbon dioxide, fine irregularities of sub-micron to nano-order can be formed on the molded body without selecting a plastic material.

  Therefore, for example, when the surface modification method of the present invention is used as an electroless plating pretreatment process, a low-cost and clean electroless plating pretreatment process can be provided. In addition, by adjusting the density of the micropores formed on the surface of the plastic, the electrical characteristics such as the dielectric constant and dielectric loss tangent of the plastic, and the optical characteristics such as low refractive index and high reflectance are made to the desired characteristics. Can be included.

  In the metal film formation method of the present invention, the metal film is formed on the surface of the plastic molded body obtained by the surface modification method of the present invention using high-pressure carbon dioxide or the like. In addition, a metal film having excellent adhesion can be formed by an anchoring effect due to fine unevenness of submicron to nano-order size and a merit of scale due to an increase in surface area. Further, since the unevenness formed on the surface of the plastic has a size of sub-micron to nano-order, the surface of the metal film is very smooth and smooth. Further, in the metal film forming method of the present invention, the surface of the plastic can be roughened without using a harmful etchant (etching solution) as in the conventional plating method, so that the metal film can be formed at low cost and cleanly. Can do.

  Embodiments of a method for modifying a surface of a plastic molded body according to the present invention, a method for forming a metal film including the method, and examples of plastic parts will be described below 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. 1 is a cross-sectional view schematically showing a plastic part 1 molded in the first embodiment. This plastic part 1 has a substantially disc-shaped plastic molded body 2 and a metal film (plating film) 3 formed on the surface thereof.

  This plastic molded body 2 is molded by an injection molding process described later. The plastic molded body 2 has an uneven surface (porous) by allowing the fluorine compound to permeate using high-pressure carbon dioxide and then removing the fluorine compound using high-pressure carbon dioxide during injection molding. It has been modified to become. Further, as will be described later, a plastic part 1 was formed by forming a metal film (plating film) 3 on the plastic molded body 2 whose surface was modified by general electroless plating.

In this example, polyphenylene sulfide (PPS), which is a thermoplastic resin, is used as a material for forming the plastic molded body 2, and perfluoro-2,5,8,11,14-pentamethyl-3,6, 9,12,15-pentaoxaoctadecanoyl fluoride (molecular formula: C ₁₈ F ₃₆ O ₆ (molecular weight: 996.2, boiling point: 235 ° C.) was used. As high-pressure carbon dioxide, supercritical carbon dioxide (supercritical carbon dioxide) Carbon).

[Molding equipment]
FIG. 2 shows a schematic structure of an injection molding apparatus 100 that forms the plastic molded body 2 shown in FIG. The injection molding apparatus 100 mainly has an injection molding machine unit 100A and a supercritical fluid generation unit 100B.

  As shown in FIG. 2, the injection molding machine unit 100 </ b> A mainly accommodates a movable mold 102 and a fixed mold 103 that constitute the molding die 101, and pellets made of PPS (a kind of plastic molding 2). It has a hopper 104 and a plasticizing cylinder 105 that melts the pellets supplied from the hopper 104 and injects them into the molding die 101. As shown in FIG. 2, when the movable mold 102 is abutted against the fixed mold 103, a disk-shaped cavity 106 having a spool at the center is formed in the molding mold 101. In this example, as shown in FIG. 2, the shape of the region other than the portion (spool or the like) corresponding to the center of the cavity 106 on the surface of the movable die 102 and the fixed die 103 on the cavity 106 side is: A flat surface (mirror surface) was used. A gas introduction mechanism 107 is connected to the flow front portion 105A in the heating cylinder (plasticizing cylinder 105). The other structure of the injection molding machine unit 100A is the same as that of a conventional injection molding machine.

  As shown in FIG. 2, the supercritical fluid generating unit 100B mainly includes a liquid carbon dioxide cylinder 111, a continuous flow system (E-260 manufactured by ISCO) 112 including two known syringe pumps, and a fluorine compound. It is comprised from the dissolution tank 113 which melt | dissolves in supercritical carbon dioxide, and each component is connected in the order by the piping 114. FIG. Moreover, the dissolution tank 113 is connected to the gas introduction mechanism 107 described above via air operated valves 115 and 116.

[Injection molding method and surface modification method]
Next, the molding method and the surface modification method of this example will be described with reference to FIGS. FIG. 3 is a partially enlarged view of a molding die 101 portion of the injection molding apparatus 100 of FIG. 3A schematically shows a state immediately after the start of injection, and FIG. 3B schematically shows a state at the end of injection. FIG. 4 shows a manufacturing process of the plastic part 1 of FIG.

  First, as shown in FIG. 2, the liquid carbon dioxide of 5 to 7 MPa stored in the liquid carbon dioxide cylinder 111 is introduced into the continuous flow system 112 and pressurized. Thereby, supercritical carbon dioxide is generated. In the continuous flow system 112, carbon dioxide is constantly pressurized and held at a predetermined pressure of 10 MPa by at least one syringe pump.

  Next, supercritical carbon dioxide is introduced from the continuous flow system 112 into the dissolution tank 113. Thereby, the fluorine compound in the dissolution tank 113 is dissolved in supercritical carbon dioxide (step S1 in FIG. 4). The dissolution tank 113 is heated to 40 ° C., and the dissolution tank 113 is supersaturated with the fluorine compound Perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl fluoride. It is prepared to become. Therefore, the fluorine compound is always saturated and dissolved in the supercritical carbon dioxide introduced from the continuous flow system 112 in the dissolution tank 113. At this time, the pressure gauge 117 of the dissolution tank 113 displayed 10 MPa.

  Next, similarly to the general injection molding apparatus 100, the screw 105A in the heating cylinder 105 is rotated to plasticize and melt the plastic pellets supplied from the hopper 104 (step S2 in FIG. 4). Further, the screw 105A was moved backward while being measured so that the molten plastic was pushed out before the screw 105A, and stopped at a predetermined measuring position.

  Next, the screw 105A was further retracted, and the measured molten plastic was depressurized. In this example, the internal pressure monitor 108 of the molten plastic provided in the vicinity of the flow front portion 105A of the heating cylinder 105 confirmed that the internal pressure decreased to 4 MPa or less.

  Next, supercritical carbon dioxide in which a fluorine compound was dissolved was introduced from the gas introduction mechanism 107 and brought into contact with the molten plastic in the flow front portion 105A of the heating cylinder 105 (step S3 in FIG. 4). The supercritical carbon dioxide in which the fluorine compound is dissolved is introduced into the molten plastic 120 in a reduced pressure state in the heating cylinder 105 and penetrates. Specifically, supercritical carbon dioxide in which a fluorine compound was dissolved was introduced as follows. First, the first air operated valve 115 is opened, and supercritical carbon dioxide in which a fluorine compound is dissolved is introduced into the pipe 114 between the second air operated valve 116 and the first air operated valve 115 to introduce a pressure gauge. 118 was boosted. Next, at the time of introduction into the heating cylinder 105, the second air operated valve 116 was opened with the first air operated valve 115 closed. In this embodiment, the amount of supercritical carbon dioxide introduced was controlled by the internal volume of the pipe 114 between the first air operated valve 115 and the second air operated valve 116. In addition, the supercritical fluid that permeates the molten plastic may be single as in this example, or may be plural.

  Next, the screw 105A was advanced by back pressure, and the screw 105A was returned to the filling start position. By this operation, carbon dioxide and a fluorine compound are diffused into the molten plastic 120 in the flow front portion 105A on the front side of the screw 105A.

  Next, the air piston 109 was driven to open the shut-off valve 110, and the molten plastic 120 was injected and filled into the cavity 106 defined by the movable mold 102 and the fixed mold 103 (step S4 in FIG. 4).

  As shown in FIG. 3A, the molten plastic in the flow front portion 105A is first filled into the cavity 106 at the time of initial filling. The fluorine compound and carbon dioxide permeating the molten plastic 120A of the flow front part 105A diffuse in the cavity 106 while being decompressed. At this time, the molten plastic 120A of the flow front part 105A flows while in contact with the surface of the mold 102 due to the fountain effect at the time of filling, and forms a skin layer 121 as shown in FIG. 4B. Thereafter, when the cavity 106 is filled with the molten plastic 120, the injection filling is completed. Thus, by bringing the fluorine compound and carbon dioxide into contact with the molten plastic 120A of the flow front portion 105A, the skin layer 121 impregnated with the fluorine compound by the molten plastic 120 in the cavity 106, and the fluorine compound inside the skin layer 121 are obtained. A core layer 122 into which (the penetrating substance) hardly penetrates is formed.

  As will be described later, the fluorine compound that permeates and remains inside the molded body 2 does not contribute to the surface function (surface roughening). Therefore, by contacting supercritical carbon dioxide in which a fluorine compound is dissolved only in the flow front portion 105A as in this example, without reducing the amount of the fluorine compound in the surface portion (skin layer 121) of the plastic molded body 2, The amount of fluorine compound used can be reduced.

  Further, in order to prevent gasification of supercritical carbon dioxide and thus suppress foaming in the cavity 106 to obtain the surface property of the molded body 2, the pressure of the molten plastic is kept high after the above-described primary filling. There is a need to. Therefore, in general, it is necessary to add counter pressure to the cavity 106 during and after injection. However, in the molding method of the present embodiment, since supercritical carbon dioxide is infiltrated only into the flow front portion 105A in the plasticizing cylinder 105, the absolute amount of carbon dioxide relative to the total amount of the filled resin is small. Therefore, the surface properties of the plastic molded body 2 are unlikely to deteriorate even without applying counter pressure to maintain the pressure of the molten plastic.

  Next, after molding the plastic molded body 2 in the cavity 106 as described above, the fluorine compound was removed (washed) from the plastic molded body 2 using supercritical carbon dioxide as a solvent (step S5 in FIG. 4). . In this example, the inside of the cavity 106 was controlled to be a temperature of 40 ° C. and a pressure of 15 MPa, and this state was continued for 30 minutes. When the temperature is 40 ° C. and the pressure is 15 MPa, carbon dioxide is in a supercritical state. By this cleaning treatment, fine irregularities (fine holes) were formed at a high density on the surface of the plastic molded body 2. That is, the surface shape of the plastic molded body 2 was physically changed by the cleaning process. Thus, in this example, the surface modification of the plastic molded body 2 was performed.

  In this example, when the fluorine compound and supercritical carbon dioxide (high pressure carbon dioxide) are contacted, the treatment is performed at a temperature near the glass transition temperature of the resin material so that the amorphous resin material swells sufficiently. It is desirable to do. Further, when only the fluorine compound introduced into the resin material is dissolved and extracted, it is desirable to perform the treatment at a temperature sufficiently lower than the glass transition temperature. This is because the size of the pores expands due to swelling of the resin during extraction.

  By this process, the fluorine compound that permeated the surface of the plastic molded body 2 made of polyphenylene sulfide, that is, Perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl fluoride A fine hole is formed in the detached part. In other words, fine holes (fine irregularities) were formed on the surface of the plastic molded body 2 by the cleaning treatment (the surface was submerged or made porous).

  FIG. 5A is an AFM (Atomic Force Microscope) observation image of the surface of the plastic molded body 2 that has not been cleaned with supercritical carbon dioxide, corresponding to the surface of the plastic molded body 2 before the cleaning treatment. It is. FIG. 5B is an AFM observation image of the surface of the plastic molded body 2 after being cleaned with supercritical carbon dioxide. As is clear from FIG. 5B, a large number of fine holes having a size of about 100 to 300 nm (submicron to nano-order) are formed on the surface of the plastic molded body 2 after the cleaning treatment. The surface of the plastic molded body 2 was modified into an uneven surface by the numerous fine holes.

[Method of forming plating film]
Next, a metal film (plating film) 3 was formed by electroless plating on the plastic molded body 2 produced as described above and having irregularities due to a large number of fine holes formed on the surface thereof. Specifically, an electroless plating film was formed as follows.

  First, the plastic molded body 2 made of polyphenylene sulfide was degreased using a known conditioner (OPC-370 manufactured by Okuno Pharmaceutical Co., Ltd.). Next, a catalyst (OPC-80 catalyst manufactured by Okuno Pharmaceutical Co., Ltd.) was applied to the plastic molded body 2 (step S6 in FIG. 4), and then an activator (OPC-500 accessor manufactured by Okuno Pharmaceutical Industry Co., Ltd.). The catalyst was activated using a calibrator MX). Next, electroless Ni plating was performed (step S7 in FIG. 4). Note that Nicolon DK manufactured by Okuno Pharmaceutical Co., Ltd. was used as the plating solution.

  As a result, no peeling or the like was confirmed on the plating film formed on the plastic molded body 2.

  Moreover, when the surface roughness of the plating film formed in this example was measured with a stylus type surface roughness measuring device (manufactured by KLA-Tencor), the arithmetic average roughness (Ra) was 15.2 nm, ten points. The average roughness (Rz) was 105.8 nm. The arithmetic average roughness (Ra) of a plating film formed by a conventional plating method (etching method) is about several μm to several tens of μm (micron order). That is, the surface roughness of the plating film formed in this example is an order of magnitude smaller than that formed by the conventional plating method (etching method), and the surface of the plating film has good smoothness. I was able to get it. That is, in this example, it was possible to obtain a plastic molded body 2 on which an electroless plating film excellent in adhesion and smoothness was formed.

  Thereafter, a conventional electric nickel plating was further applied in the atmosphere for about 20 μm, and a high temperature and high humidity environment test (temperature 80 ° C., humidity 90% Rh, 500 hours) was performed. As a result, in all the tests described above, peeling or blistering of the metal film 3 was not recognized. Further, when a peel test with a tape was performed, no peeling or the like occurred.

  The same results were obtained when 10 cycles of a high temperature environmental test and a heat cycle test in which the temperature was switched between −40 ° C. and 85 ° C. under conditions of a temperature of 150 ° C. and a standing time of 500 hours were performed. Obtained.

  That is, according to the plating film forming method of this example, the metal film 3 having high adhesion and smoothness can be formed on the plastic molded body (polymer member) 2 by a simple method using the conventional method as it is, In addition, the entire process can be simplified by modifying the surface of the resin molding to eliminate the degreasing process, etching process, neutralization and wetting process, catalyst application process, catalyst activation process, etc. I found out that

  In Example 2, as in Example 1, when a plastic molded body (plastic) 2 was molded by injection molding, supercritical carbon dioxide was used to infiltrate the fluorine compound into the plastic molded body 2 and then supercritical. By removing the fluorine compound from the plastic molded body 2 using carbon dioxide, the surface was modified to be uneven. In addition, a metal catalyst nucleus (metal fine particles) is imparted to the plastic molded body 2 whose surface is modified using supercritical carbon dioxide, and then a metal film (plating film) 3 using supercritical carbon dioxide. The plastic part 1 was formed.

  In this example, metal catalyst nuclei were imparted to the plastic molded body 2 (polymer member) from which the fluorine compound had been removed by a batch method. Moreover, the metal film 3 formed an emulsion with a mixed solution of supercritical carbon dioxide and an electroless Ni plating solution, and performed electroless plating in the emulsion of the mixed solution. In addition, after forming an electroless plating film using supercritical carbon dioxide, a copper or silver film may be further formed thereon.

  The basic structure of the plastic part 1 of this example and the process until obtaining the plastic molded body 2 from which the fluorine compound is extracted are the same as those in the first embodiment, and the description thereof is omitted. Here, a description will be mainly given of a plating film forming process for the plastic molded body 2 that has been modified to have an uneven surface by extracting a fluorine compound.

[Method of forming plating film]
First, the plastic molded body 2 formed by the method of Example 1 is mounted together with a metal complex in a high-pressure container of a surface modification device (not shown). At this time, the plastic molded body 2 was floated and held in the central portion of the high-pressure vessel so that the entire surface of the plastic molded body 2 could come into contact with supercritical carbon dioxide introduced into the high-pressure vessel later. In this example, hexafluoroacetylacetonato palladium (II) was used as the metal complex.

  After the plastic molded body 2 and the metal complex were accommodated in a high-pressure vessel, 15 MPa supercritical carbon dioxide was introduced into the high-pressure vessel. The metal complex charged in the high-pressure vessel is dissolved in supercritical carbon dioxide and penetrates into the inside of the plastic molded body 2 together with the supercritical carbon dioxide. By holding this pressure at 150 ° C. for 30 minutes, a part of the metal complex that has penetrated into the entire surface of the plastic molded body 2 is reduced.

  Next, electroless plating was applied to the plastic molded body 2 infiltrated with the metal complex, and a plating film was formed on the surface of the plastic molded body 2. Actually, electroless plating was performed in a mixed solution of a supercritical carbon dioxide and an electroless plating solution. First, the plastic molded body 2 provided with the metal complex (metal catalyst nucleus, metal fine particles) was taken out from the high-pressure vessel of the surface reformer and mounted in the high-pressure vessel of the electroless plating apparatus 200.

  FIG. 6 shows an electroless plating apparatus 200. The electroless plating apparatus 200 mainly includes a liquid carbon dioxide cylinder 201, a syringe pump 202, and a high-pressure container 203. The high-pressure vessel 203 can be temperature-controlled at an arbitrary temperature from 30 ° C. to 145 ° C. with temperature-controlled water whose temperature is controlled by a temperature controller (not shown) that flows through the temperature adjustment channel 211. The high-pressure container 203 can seal high-pressure gas or the like inside by sealing the container main body 203A and the lid 203B with a polyimide seal 203C containing a known spring.

  The plastic molded body 2 is held by suspending the plastic molded body 2 from the lid 203B of the high-pressure vessel 203 so that the entire surface thereof can come into contact with supercritical carbon dioxide introduced into the high-pressure vessel 203 later. The high-pressure vessel 203 is filled with an electroless nickel plating solution 204 to 70% of its internal volume, and a magnetic stirrer 205 is provided.

  Note that it is desirable to use a material that is not easily corroded for the high-pressure vessel 203, and SUS316, SUS316L, Inconel, Hastelloy, titanium, or the like can be used. In this embodiment, SUS316L was used. In the present invention, when the inner wall surface of the high-pressure vessel 203 is in contact with the electroless plating solution 204, the inner wall surface may be coated with a non-plated growth film so that the plating film does not grow inside the vessel. desirable. As the material of the non-plated growth film, DLC (diamond-like carbon), PTFE (polytetrafluoroethylene), PEEK (polyethyl ether ketone), or the like can be used. It is coated by CVD (Chemical Vapor Deposition Chemical Vapor Deposition).

  Further, the kind of electroless plating solution 204 that can be used in the present invention is arbitrary, such as nickel-phosphorus, nickel-boron, palladium, copper, silver, cobalt, etc. In this embodiment, nickel-phosphorous was used. Since high-pressure carbon dioxide penetrates into the plating solution 204, the pH of the plating solution 204 is lowered. Therefore, in the present invention, a solution that can be plated in a neutral or weakly alkaline to acidic bath is suitable, and nickel-phosphorus has a pH of 4-6. It is desirable because it can be used within the range of In addition, when the pH is lowered, the phosphorous concentration is increased and the precipitation rate is lowered. Therefore, the pH of the plating solution 204 may be raised in advance.

  In particular, regarding the electroless plating using high-pressure carbon dioxide of the present invention, the plating reaction may be performed in an electroless plating solution 204 containing alcohol. Alcohol is easily compatible with supercritical carbon dioxide at high pressure without stirring. According to the study by the present inventors, the plating liquid 204 is mainly composed of water, but by adding alcohol, the high-pressure carbon dioxide and the plating liquid 204 are easily mixed stably. In order to obtain a stable mixed state, it is not necessary to use a fluorine compound or to stir. Further, when alcohol is added to the plating solution 204, the surface tension of the plating solution 204 is lowered. Therefore, it is convenient for the plating solution 204 to penetrate into the plastic molded body 2 together with the high-pressure carbon dioxide to grow the plating reaction therein. It is.

  In general, the electroless plating solution 204 is diluted with a stock solution containing metal ions, a reducing agent, or the like with water according to a component ratio recommended by the manufacturer, for example. What is necessary is just to add to water in a ratio. The volume ratio of water and alcohol is arbitrary, but it is preferably in the range of 10 to 80% of the plating solution 204. If the alcohol component ratio is less than 10%, it is difficult to obtain a stable mixed solution. If the alcohol component ratio is greater than 80%, for example, nickel sulfate used for nickel-phosphorous plating is insoluble in an organic solvent such as ethanol, so that the bath may not be stable.

  In the present embodiment, 150 ml of Nikon DK manufactured by Okuno Pharmaceutical Co., Ltd. as a stock solution containing a nickel sulfate metal salt, a reducing agent and a complexing agent is added to the plating solution 204, 350 ml of water, and ethanol as alcohol. 500 ml each was added and mixed. That is, the alcohol component ratio was 50% in the plating solution 204. Since nickel sulfate is insoluble in alcohol, it was found that when the amount of alcohol added exceeds 80%, a large amount of nickel sulfate precipitates, which makes it impossible to apply.

  In addition, although the kind of alcohol which can be used for this invention is arbitrary, methanol, ethanol, n-propanol, isopropanol, butanol, heptanol, ethylene glycol etc. can be used, In this Example, ethanol was used.

  After the plastic molded body 2 provided with the complex was attached to the metal electroless plating apparatus 200 in FIG. 6, supercritical carbon dioxide was introduced into the electroless plating apparatus 200. Supercritical carbon dioxide is pressurized from the liquid carbon dioxide cylinder 111 through the filter 206 to 15 MPa by the syringe pump 202 and introduced into the high-pressure vessel 203 from the manual valve 207. The syringe pump 202 executes control to keep the pressure constant with the manual valve 207 open, and absorbs pressure fluctuations caused by changes in the internal temperature of the high-pressure vessel 203 or the density of supercritical carbon dioxide. The internal pressure of the container 203 can be stably maintained.

  The temperature of the high-pressure vessel 203 and the plating solution 204 when supercritical carbon dioxide is introduced into the high-pressure vessel 203 is maintained at 50 ° C. by the temperature adjustment water flowing through the temperature adjustment flow path 211. On the other hand, the reaction temperature of the plating solution 204 is 70 ° C to 85 ° C. Therefore, at the time of introducing the supercritical carbon dioxide, the electroless plating solution 204 only enters the inside of the plastic molded body 2 together with the supercritical carbon dioxide, even if the magnetic stirrer 205 is rotated at a high speed. No plating grows at 2.

  Thereafter, the temperature of the plating solution 204 compatible with the plastic molding 2 and supercritical carbon dioxide was raised to the reaction temperature (85 ° C.) of the plating solution 204. As a result, a plating reaction occurred in the storage container 203.

  Thus, by introducing supercritical carbon dioxide at a temperature lower than the plating reaction temperature and then raising the temperature to the plating reaction temperature, the electroless plating solution 204 penetrates into the plastic molded body 2 together with the high-pressure carbon dioxide in advance. However, the growth of the plating film starts in the state where the previous penetration has been made. As a result, the plating film is formed so as to react inside the plastic molded body 2 and grow from the inside of the plastic molded body 2.

  After the plating process, the magnetic stirrer 205 was stopped. Thereby, the carbon dioxide and the plating solution 204 are separated into two phases in the container. Thereafter, the manual valve 207 on the introduction side was closed, the manual valve 208 on the discharge side was opened, and carbon dioxide was exhausted. When the plastic molded body 2 of this example was taken out from the high-pressure vessel 203, a metallic luster was observed on the entire surface.

  Next, a peel test using the same tape as in Example 1 was performed on the plastic molded body 2 on which the plating film 3 was formed. As a result, peeling of the plating film 3 and the like were not confirmed.

  Further, when the surface roughness of the plating film 3 formed in this example was measured with a stylus type surface roughness measuring device (manufactured by KLA-Tencor), the arithmetic average roughness (Ra) was 22.3 nm, 10%. The point average roughness (Rz) was 107.2 nm, which was an order of magnitude smaller than the plating film (Ra≈several to several tens of μm) formed by the conventional plating method (etching method). . That is, in this example, it was possible to obtain a plastic molded body 2 on which the electroless plating film 3 having excellent adhesion and smoothness was formed.

  Furthermore, the plastic molded body 2 having the electroless plating film 3 formed on the surface thereof is subjected to conventional electro nickel plating in the atmosphere for about 20 μm, and a high temperature and high humidity environment test (temperature 80 ° C., humidity 90% Rh, 500 Time). As a result, no peeling or blistering of the metal film 3 was observed in all tests. Further, when a peel test with a tape was performed, peeling or the like did not occur. In addition, a high temperature test under the conditions of a temperature of 150 ° C. and a standing time of 500 hours and a test in which a heat cycle for switching the temperature between −40 ° C. and 85 ° C. was repeated 10 times were performed. I was able to get it.

  That is, in the plating film forming method of this example, the metal film 3 having high adhesion and smoothness can be formed on the plastic molded body (polymer member) 2 by a simple method using the conventional method almost as it is, By surface modification in resin molding, the whole process can be simplified by omitting the degreasing process, etching process, neutralization and wetting process, catalyst application process, catalyst activation process, etc. I understood.

  In Example 3, as in Example 1, when the plastic molded body 2 (plastic) is molded by injection molding, superplastic carbon dioxide is used to remove the fluorine compound and the metal catalyst core (metal fine particles). Then, the fluorine compound was removed from the plastic molded body 2 to modify the surface so as to be uneven. Further, a plastic part 1 was formed by forming a metal film (plating film) 3 using supercritical carbon dioxide on the plastic molded body 2 whose surface was modified.

In addition, the two types of substances that have permeated the plastic molded body 2 are fluorine compounds (Perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12) permeated before molding in Example 1. , 15-pentaoxaoctadecanoyl fluoride (molecular formula: C ₁₈ F ₃₆ O ₆ , molecular weight: 996.2, boiling point: 235 ° C.) and a metal complex (hexafluoroacetylacetonato palladium (II)) permeated after molding in Example 2 In the present invention, a metal complex containing fluorine and dissolved in supercritical carbon dioxide (high-pressure carbon dioxide) and a fluorine compound are mixed, so that the metal complex is easily segregated on the plastic surface after molding. It is considered that the heat resistance of the complex is temporarily improved by surrounding the fluorine-containing complex with the fluorine compound, and it becomes easy to bleed out to the surface together with the fluorine compound. Polyphenylene sulfide (PPS), which is a thermoplastic resin, was used as a forming material for 2. In forming the metal film 3, an emulsion was formed with a mixed solution of supercritical carbon dioxide and electroless Ni plating solution, Electroless plating was performed in an emulsion of the mixed solution.

[Molding equipment]
In this example, the injection molding apparatus 100 shown in FIG. 2 was used. In the dissolution tank 113, the above-described two kinds of penetrating substances (fluorine compound and metal complex) are charged so as to be supersaturated. Otherwise, injection molding was performed in the same manner as in Example 1, and plating was performed.

[Injection molding method and surface modification method]
FIG. 7 shows a manufacturing process of the plastic part 1 according to the third embodiment. First, as in Example 1, supercritical carbon dioxide in which two kinds of permeation substances (fluorine compound and fluorine-containing metal complex) are dissolved is introduced into the molten plastic 120 in the heating cylinder 105, and the two kinds of permeation substances are obtained. A plastic molded body 2 impregnated in the surface portion 121 was produced (steps S21 to S24 in FIG. 7). In this molding process, most of the penetrated metal complex is reduced to metal fine particles by the heat of the molten plastic 120.

  Next, the high-pressure carbon dioxide was used as a solvent to remove the fluorine compound from the plastic molded body 2 (step S25 in FIG. 7). The temperature of the cavity 106 in the molding die 101 was controlled to 40 ° C. and the internal pressure of the cavity 106 was set to 15 MPa, and this state was maintained for 30 minutes. Accordingly, the plastic molded body 2 is cleaned with the supercritical carbon dioxide. Of the penetrating substance penetrating into the plastic molded body 2, the fluorine compound is detached from the surface of the plastic molded body 2, and fine irregularities (fine holes) are formed on the surface. The metal fine particles as the other penetrating substance were hardly removed by this washing treatment, and penetrated into the surface of the plastic molded body 2 even after washing. In this example, the surface of the plastic molded body 2 was modified in this way.

[Method of forming plating film]
Next, as in Example 2, a mixed solution of supercritical carbon dioxide and electroless plating solution was formed, and the surface-modified plastic molded body 2 was immersed therein. A metal film 3 was formed on the surface of the plastic molded body 2 by this electroless plating. Thereby, the plastic part 1 of Example 3 was formed (step S26 in FIG. 7).

  Next, a peel test using the same tape as in Example 1 was performed on the plastic part 1. As a result, peeling of the plating film 3 and the like were not confirmed.

  Further, when the surface roughness of the plating film 3 formed in this example was measured with a stylus type surface roughness measuring device (manufactured by KLA-Tencor), the arithmetic average roughness (Ra) was 27.6 nm, 10%. The point average roughness (Rz) is 105.3 nm, which is an excellent surface roughness that is orders of magnitude smaller than the plating film (Ra≈several μm to several tens μm) formed by the conventional plating method (etching method). (Good smoothness) was obtained. That is, in this example, it was possible to obtain a plastic molded body 2 on which the electroless plating film 3 having excellent adhesion and smoothness was formed.

  Then, about 20 μm of conventional electric nickel plating was applied in the atmosphere, and a high temperature and high humidity environment test (temperature 80 ° C., humidity 90% Rh, 500 hours) was performed. As a result, peeling and blistering of the metal film 3 were not observed in all tests. Further, when a peel test with a tape was performed, no peeling or the like occurred.

  Similar results were obtained when a high-temperature environment test under conditions of a temperature of 150 ° C. and a standing time of 500 hours and a test in which a heat cycle for switching the temperature between −40 ° C. and 85 ° C. was repeated 10 times. was gotten.

  That is, according to the plating film forming method of this example, the metal film 3 having high adhesion and smoothness can be formed on the plastic molded body (polymer member) 2 by a simple method using the conventional method as it is, In addition, the entire process can be simplified by modifying the surface of the resin molding to eliminate the degreasing process, etching process, neutralization and wetting process, catalyst application process, catalyst activation process, etc. I found out that

  In Example 4, when the plastic molded body 2 (plastic) is molded by injection molding, a fluorine compound and a metal complex are infiltrated into the surface of the plastic molded body 2 using high-pressure carbon dioxide, and then supercritical carbon dioxide is added. By using it and removing the fluorine compound from the plastic molded body 2, the surface was modified to be uneven. Further, a plastic part 1 was formed by forming a metal film (plating film) 3 using supercritical carbon dioxide on the plastic molded body 2 whose surface was modified.

  In this example, however, the sandwich injection molding apparatus 300 having two cylinders is used in the injection molding of the plastic molded body 2. Of the two cylinders, a fluorine compound and a metal complex are introduced into the first plasticizing cylinder 301 that forms the outer skin after being dissolved in supercritical carbon dioxide.

  In this example, the fluorine compound was removed with a mixed solution of supercritical carbon dioxide and electroless Ni plating solution, and the metal film 3 was formed by performing electroless plating in the mixed solution.

[injection molding]
FIG. 8 shows a schematic configuration of the sandwich injection molding apparatus 300. 9 to 14 are enlarged views of main parts in each process described later. The sandwich injection molding apparatus 300 includes a first plasticizing cylinder 301 that forms an outer skin and a second plasticizing cylinder 302 that forms an inner skin. In the first plasticizing cylinder 301 forming the outer skin, a fluorine compound and a metal complex are introduced by being dissolved in supercritical carbon dioxide. Note that the fluorine compound and the metal complex may be dissolved in the supercritical carbon dioxide and introduced into the second plasticizing cylinder 302.

In addition, although the kind of functional material dissolved in supercritical carbon dioxide is arbitrary, in this example, a fluorine compound and a metal complex were used. As the fluorine compound, the fluorine compound used in Example 1 (Perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl
fluoride (molecular formula: C ₁₈ F ₃₆ O ₆ , molecular weight: 996.2, boiling point: 235 ° C.) was used, and hexafluoroacetylacetonato palladium (II) of Example 2 was used as the metal complex. Also, these functional materials are introduced by melting in supercritical carbon dioxide having a temperature of 40 ° C. and a pressure of 10 MPa.

  Further, the type of the resin material that forms the outer skin and in which the functional material is dispersed by the high-pressure carbon dioxide is arbitrary as long as it is a thermoplastic resin material, and can be applied to either amorphous or crystalline. Used polyphenylene sulfide (PPS).

  Moreover, the kind of the resin material forming the inner skin is arbitrary, and the same kind as the outer skin can be selected. Further, by using a material in which glass fibers, inorganic fillers and the like are mixed only in the endothelium, it is possible to obtain a molded article having good surface properties and excellent mechanical strength, dimensional stability and hygroscopicity. In this example, polyphenylene sulfide (PPS) mixed with 30% glass fiber was used.

  The forms of the molding die 303 and the cavity 306 are not limited to planar shapes, and may be any three-dimensional shape. In this embodiment, the cavity 106 formed by the fixed mold 304 and the movable mold 305 can take two headlamp reflectors (a kind of plastic molded body 2) for automobiles around the spool. Shaped. The fixed mold 103 is fixed to a fixed platen 307 of the molding machine, the movable mold 102 is fixed to the movable platen 308, and is driven by a mold clamping mechanism, so that the movable platen 308 contacts and separates from the fixed platen 307. And the molding die 101 opens and closes.

[Injection molding method and surface modification method]
FIG. 15 shows a manufacturing process of the plastic part 1 according to the fourth embodiment. In this example, the permeation substance in supercritical carbon dioxide was dissolved and introduced into the plasticizing cylinder 105 by the following method.

  First, the carbon dioxide supplied from the liquid carbon dioxide cylinder 331 is increased to a predetermined pressure by the syringe pump 332, and the fluorine compound and the metal complex charged in the dissolution tank 333 are dissolved so as to be supersaturated (FIG. 15). Middle step S31). At this time, the section up to the introduction cylinder 313 was pressurized. In the present embodiment, the syringe pump 332 is held at a constant pressure from the dissolution tank 333 to the introduction cylinder 313 except for the timing of introducing high-pressure carbon dioxide and functional material into the plasticizing cylinder 301 at the time of plasticization measurement described later. It was set to control.

  The first screw 301 </ b> A built in the first plasticizing cylinder 301 was provided with two decompression points as vent portions 311 and 312, respectively. As shown in FIG. 9, during plasticization measurement, the internal pressure in front of the screw 301 </ b> A rises due to the rotation of the first screw 301 </ b> A, and the screw 301 </ b> A begins to retreat, but at this time, the vent provided at the lower portion of the introduction cylinder 313 In the part 312, the molten resin was decompressed, and at the same time, the air-driven introduction piston 313 </ b> A in the introduction cylinder 313 was raised and penetrated into the decompression resin (steps S <b> 32 to S <b> 33 in FIG. 15). During the permeation time of the high-pressure carbon dioxide in which the functional material was dissolved into the resin, the syringe pump 332 was switched to flow control, and a constant flow of high-pressure carbon dioxide was injected into the plasticizing cylinder 105 for a certain time.

  The molding apparatus of this example has a function of exhausting high-pressure carbon dioxide dissolved in the functional material and infiltrated into the molten resin before injection filling. As shown in FIG. 10, the resin was depressurized by the first screw 301A and the second vent portion 312 during the plasticization measurement, and the high-pressure carbon dioxide was depressurized below the supercritical pressure to be gasified. At the same time, the exhaust piston 314A built in the discharge cylinder 314 was raised, and part of the gasified carbon dioxide was exhausted from the plasticizing cylinder 301. After passing through the filter 315 and the buffer container 316, the carbon dioxide was depressurized by the pressure reducing valve 317 so that the pressure gauge 318 became 0.5 MPa and exhausted from the vacuum pump 319.

  Resin pellets (not shown) supplied from the first hopper 104 are plasticized and melted in a state where the penetrating substance (fluorine compound, metal complex) and high-pressure carbon dioxide are uniformly diffused in the first plasticizing cylinder 301. The flow of the first plasticizing cylinder 301 and the second plasticizing cylinder 302 to the mold is controlled by the rotation of the rotary valve. For example, when plasticizing and metering in the first plasticizing cylinder 301, as shown in FIGS. 9 and 10, the rotary valve is installed in the second so that the pressurized resin does not leak into the mold from the tip of the nozzle. The resin flow path is set between the plasticizing cylinder 302 and the nozzle.

  As shown in FIG. 10, the introduction piston 313A of the introduction cylinder 313 and the discharge piston 314A of the discharge cylinder 314 are moved down at the same time as the plasticization measurement of the first resin material is completed by the first screw 301A. 332 was switched to pressure control, and introduction and exhaust of high-pressure carbon dioxide were stopped.

  Next, as shown in FIG. 11, when the molten resin plasticized and measured by the first plasticizing cylinder 301 is injected and filled into the mold 303 and the cavity 106 by the advancement of the first screw 301A. The rotary valve 321 was rotated to form a resin flow path between the first plasticizing cylinder 301 and the nozzle 322.

  At the same time, in the second plasticizing cylinder 302, the resin pellets that form the endothelium supplied from a second hopper (not shown) were plasticized and measured by the rotation of the second screw 302A. As shown in FIG. 12, immediately before the first resin is completely filled, the plasticization measurement of the second resin is completed.

  Immediately after the first resin material forming the outer skin is filled from the first plasticizing cylinder 301 (step S34 in FIG. 15), the rotary valve 321 is rotated, and as shown in FIG. The second resin material was injected and filled from the control cylinder 302 (step S35 in FIG. 15). Then, as shown in FIG. 14, a sandwich molded body (a kind of plastic molded body 2) 343 is injection molded in the cavity 106. The outer skin 341 of the sandwich molded body 343 is formed of a first resin material in which two kinds of penetrating substances (fluorine compound and fluorine-containing metal complex) are dispersed, and the inner skin 342 is formed of a second resin material. Has been. In this molding process, most of the penetrated metal complex is reduced to metal fine particles by the heat of the molten resin. After cooling and solidifying, the mold was opened, and the sandwich molded body 343 was taken out to produce a plastic molded body 2 with two kinds of penetrating substances impregnated on the surface.

[Fluorine compound extraction method and plating film formation method]
FIG. 16 shows an electroless plating apparatus 200. The electroless plating apparatus 200 has substantially the same configuration as that of FIG. However, in this example, the plating solution and the plastic molded body 2 are accommodated in a Teflon (registered trademark) inner container 251 kept at room temperature, and the Teflon (registered trademark) inner container 251 is preliminarily adjusted to 90 ° C. The high-pressure vessel 203 is accommodated. In addition, 15 MPa of supercritical carbon dioxide is introduced into the high-pressure vessel 203 immediately after being accommodated.

Immediately after supercritical carbon dioxide is introduced into the high-pressure vessel 203, the internal vessel 251 uses a resin having low thermal conductivity, so the temperature in the internal vessel 251 does not rise rapidly. For a while, it is maintained at a low temperature below the temperature at which the plating reaction occurs. For this reason, supercritical carbon dioxide is a fluoro compound, Perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15- Pentaoxaoctadecanoyl fluoride (molecular formula: C ₁₈ F ₃₆ O ₆ , molecular weight: 996.2, boiling point: 235 ° C.) is removed from the plastic molded body 2. Thereby, fine irregularities (fine holes) are formed on the surface of the plastic molded body 2 (step S36 in FIG. 15).

  Thereafter, the temperature in the inner container 251 increases with time. The temperature in the inner container 251 eventually rises to the plating reaction temperature. As a result, a plating reaction occurs in the inner container 251, and the plating film 3 grows on the surface of the plastic molded body 2 (step S37 in FIG. 15). At this time, in the method of forming the plating film 3 of this embodiment, since the electroless plating solution 204 penetrates in advance to the metal fine particles existing inside the plastic molded body 2 as described above, the plastic molded body The plating film 3 grows using not only the surface of 2 but also the metal fine particles existing inside thereof as catalyst nuclei. That is, in the plating film forming method of this embodiment, the plating film 3 grows even in the free volume inside the plastic molded body 2 and is formed in a state where it is bitten into the plastic molded body 2 and has a strong adhesion strength. have.

  Next, the peel test using the tape similar to Example 1 was done with respect to the plastic molding 2 in which the plating film 3 was formed. As a result, peeling of the plating film 3 and the like were not confirmed.

  Further, when the surface roughness of the plating film 3 formed in this example was measured with a stylus type surface roughness measuring apparatus (manufactured by KLA-Tencor), the arithmetic average roughness (Ra) was 31.2 nm, 10%. The point average roughness (Rz) is 111.5 nm, which is an order of magnitude smaller than the plating film (Ra≈several μm to several tens μm) formed by the conventional plating method (etching method). Good surface roughness (good smoothness) was obtained. That is, in this example, it was possible to obtain a plastic molded body 2 on which the electroless plating film 3 having excellent adhesion and smoothness was formed.

  Thereafter, conventional nickel electroplating was further applied in the atmosphere for about 20 μm, and a high temperature and high humidity environment test (temperature 80 ° C., humidity 90% Rh, 500 hours) was performed. As a result, no peeling or blistering of the metal film 3 was observed in all tests. Further, when a peel test with a tape was performed, no peeling or the like occurred.

  Moreover, when the high temperature test on the conditions of temperature 150 degreeC and leaving time 500 hours and the heat cycle test which switches temperature between -40 degreeC and 85 degreeC 10 times were performed, the same result was obtained.

  That is, according to the plating film forming method of this example, not only can the process be simplified by a simple method, but also a metal film 3 having high adhesion and smoothness can be formed on the plastic molded body 2.

  In Example 5, a method of modifying the surface of the plastic molded body 2 that does not use supercritical carbon dioxide during injection molding, and a method of forming the plating film 3 on the surface of the plastic molded body 2 using supercritical carbon dioxide. An example will be described.

In this example, Perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl fluoride (molecular formula: C ₁₈ F ₃₆ O ₆ , molecular weight: 996.2, boiling point) : 235 ° C.), and polycarbonate was used as a material for forming the plastic molded body 2. The procedure from the molding method and surface modification method of the plastic molded body 2 of this example to the plating film forming method will be described below with reference to FIG.

[Molding method and surface modification method]
First, in this example, before injection molding, polycarbonate as a forming material of the plastic molded body 2 and perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12 as a penetrating substance are used. , 15-pentaoxaoctadecanoyl fluoride was kneaded in a known extruder to produce pellets (first plastic resin). Specifically, the mixing ratio of Perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl fluoride to polycarbonate is set to 30% and supplied to the extrusion molding machine. The resin was extruded from the die at the tip of the nozzle while melting and kneading. The obtained molded body was cooled with a cooling bath and granulated with a pelletizer. At this time, in order to make the kneading of polycarbonate and Perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15-pentaoxaoctadecanoyl fluoride uniform, the end group was modified with an additive. Modifications such as improving affinity may be performed.

  In this example, before injection molding, as a second pellet, Perfluoro-2,5,8,11,14-pentamethyl-3,6,9,12,15- A pellet (second plastic resin) made of polycarbonate not containing pentaoxaoctadecanoyl fluoride was produced (step S41 in FIG. 17). In the present invention, the material for forming the plastic molded body 2 is arbitrary as long as it is a thermoplastic resin that can be extruded.

  Next, a plastic molded body 2 was molded using a known sandwich molding apparatus using the two types of pellets. The sandwich molding apparatus used in this example is a kind of the injection molding apparatus 100, and includes two heating cylinders and molds in circulation with their tip nozzles as in the case of FIG. The sandwich molding apparatus injects molten resin from one heating cylinder (hereinafter also referred to as a first heating cylinder) into a mold and then melts from the other heating cylinder (hereinafter also referred to as a second heating cylinder). The plastic molded body 2 is molded by injection-filling resin.

  Specifically, first, pellets of polycarbonate (first plastic resin) containing a fluorine compound were supplied into the first heating cylinder, and plasticized and melted (step S42 in FIG. 17). Moreover, pellets of polycarbonate (second plastic resin) not containing a fluorine compound were supplied into the second heating cylinder and plasticized and melted (step S43 in FIG. 17).

  Next, a molten resin of polycarbonate containing a fluorine compound was injected into the mold from the first heating cylinder (step S44 in FIG. 17). Next, the injection route of the molten resin was switched to the second heating cylinder, and the molten resin of polycarbonate containing no fluorine compound was injected and filled into the mold from the second heating cylinder (step S45 in FIG. 17).

  As a result, a plastic molded body 2 having a core layer 342 made of polycarbonate containing no fluorine compound and a skin layer 341 made of polycarbonate containing fluorine compound formed on the core layer 342 was obtained.

  In this example, in this way, a plastic molded body 2 having a surface impregnated with a fluorine compound was produced without using supercritical carbon dioxide during injection molding. In addition, as a shaping | molding method of the plastic molding 2, not only sandwich molding but insert molding, two-color molding, etc. may be used.

  Fluorine compound was removed from the surface of the plastic molded body 2 of the plastic molded body 2 produced by sandwich molding using high pressure carbon dioxide as a solvent (step S46 in FIG. 17).

[Method of forming plating film]
Next, supercritical carbon dioxide in which the plating catalyst nucleus was melted was brought into contact with the plastic molded body 2 having microholes formed on the surface, thereby imparting a plating catalyst nucleus to the surface portion of the plastic molded body 2 (see FIG. 17 step S47).

  Next, the plastic molded body 2 provided with the plating catalyst core was dipped in a mixed solution of supercritical carbon dioxide and electroless plating solution to form a plating film 3 on the surface of the plastic molded body 2 (step in FIG. 17). S48).

  Next, the peel test using the tape similar to Example 1 was done with respect to the plastic molding 2 in which the plating film 3 was formed. As a result, no peeling of the plating film 3 was confirmed.

  Further, when the surface roughness of the plating film 3 formed in this example was measured with a stylus type surface roughness measuring device (manufactured by KLA-Tencor), the arithmetic average roughness (Ra) was 30.9 nm, 10%. Good surface roughness with a point average roughness (Rz) of 117.2 nm, which is orders of magnitude smaller than a plating film (Ra≈several to several tens of μm) formed by a conventional plating method (etching method). (Good smoothness) was obtained. That is, in this example, it was possible to obtain a plastic molded body 2 on which the electroless plating film 3 having excellent adhesion and smoothness was formed.

  Thereafter, further, conventional electro nickel plating was applied on the plating film 3 in the atmosphere in an amount of about 20 μm, and a high temperature and high humidity environment test (temperature 80 ° C., humidity 90% Rh, 500 hours) was performed. As a result, no peeling or blistering of the metal film 3 was observed in all tests. Further, when a peel test with a tape was performed, no peeling or the like occurred.

  Similar results were obtained when a high temperature test and a heat cycle test in which the temperature was switched 10 times between −40 ° C. and 85 ° C. under conditions of a temperature of 150 ° C. and a standing time of 500 hours were performed.

  That is, according to the plating film forming method of this example, not only can the process be simplified by a simple method, but also a metal film 3 having high adhesion and smoothness can be formed on the plastic molded body 2.

  Table 1 summarizes the test results after plating in Examples 1 to 5.

  From these results, in all Examples, good results were obtained in terms of appearance, plating film adhesion, and plated surface smoothness. This is because fine irregularities can be uniformly dispersed at a high density without impairing the surface smoothness of the plastic molded body 2 as compared with the case where the substrate surface is roughened to the micron order using a conventional etchant. As a result, it is considered that a sufficient anchoring effect was obtained.

  When the surface roughness of the metal film 3 is large, the reflectance and electrical characteristics (resistance, etc.) of the metal film 3 are deteriorated. However, in the method for forming a plating film of the present invention, the molded body 2 Since the surface roughness of the plastic part 1 can be made extremely small, for example, the metal film of the plastic part 1 used in applications such as a reflector that requires high reflectivity, a high-frequency electric circuit or an antenna that requires good electrical characteristics, etc. 3 is suitable as a forming method.

  In Examples 1-5, although the example which dissolved the osmosis | permeation substance (fluorine compound and / or metal complex) in the high pressure carbon dioxide with the dissolution tank was demonstrated, this invention is not limited to this. For example, using a storage tank such as a cylinder filled with high-pressure carbon dioxide in which an osmotic substance is dissolved in advance, the high-pressure carbon dioxide in which the osmotic substance is dissolved is directly supplied (introduced) from the storage to the plastic (or molten resin). good.

  In Example 6, Example 1 was used except that 1H, 1H-Perfluoro (2,5-dimethyl-3,6-dioxanonan-1-ol) (molecular weight: 482.1, boiling point: 155 ° C.) was used as the fluorine compound. Injection molding, surface modification, and plating film 3 were formed by the same method as described above.

  And the peel test using the tape similar to Example 1 was done with respect to the plastic molding 2 in which this plating film 3 was formed. As a result, no peeling of the plating film 3 was confirmed.

  Further, when the surface roughness of the plating film 3 formed in this example was measured with a stylus type surface roughness measuring device (manufactured by KLA-Tencor), the arithmetic average roughness (Ra) was 12.3 nm, 10%. The point average roughness (Rz) is 101.8 nm, which is an order of magnitude smaller than that of a plating film (Ra≈several μm to several tens μm) formed by a conventional plating method (etching method). A surface roughness (good smoothness) was obtained.

  That is, in this example, it was possible to obtain a plastic molded body 2 on which the electroless plating film 3 having excellent adhesion and smoothness was formed.

  After that, the conventional nickel electroplating is applied in the atmosphere for about 20 μm, high temperature and high humidity environment test (temperature 80 ° C., humidity 90% Rh, 500 hours), and high temperature test under conditions of temperature 150 ° C. and standing time 500 hours. And went. As a result, no peeling or blistering of the metal film 3 was observed, and no peeling or the like occurred in a peel test using a tape performed thereafter.

  Furthermore, the heat cycle test which switches temperature 10 times between -40 degreeC and 85 degreeC was done. Even in this case, peeling or blistering of the metal film 3 was not recognized. In a subsequent peel test using a tape, peeling was observed in part, but it was determined that the plating film 3 had an adhesive force with no practical problem.

  Table 2 summarizes the test results after plating of Example 6.

  In Example 7, at least a resin film (plastic sheet) having a fluorine compound and a metal complex on the surface was prepared by extrusion molding, and then the plastic surface modification method for removing the fluorine compound and the surface modification method were used. An example of a method for forming a plating film (metal film) on the surface of the obtained plastic molded product will be described.

  The resin material that can be used for the resin film is arbitrary as long as it is a thermoplastic resin that can be extruded, but in this example, polycarbonate was used. In addition, the material that penetrates into the resin film is also arbitrary, but in this example, the fluoro compound is Perfluorotripentylamine (molecular formula: C15F33N (manufactured by Shinquest Laboratory, molecular weight: 821.1, boiling point: 220 ° C.)), or as a metal complex. Hexafluoroacetylacetonato palladium (II), which is a fluorine-based metal complex, was used, and in this example, liquid high-pressure carbon dioxide was used as the high-pressure fluid.

[Molding apparatus] First, the molding apparatus of this example used for producing a resin film will be described. A schematic configuration diagram of the molding apparatus used in this example is shown in FIG. As shown in FIG. 18, the molding apparatus 400 used in this example mainly includes an extrusion molding unit 401, a carbon dioxide supply unit 402, and a carbon dioxide discharge unit 403.

  As shown in FIG. 18, the extrusion machine unit 401 mainly includes a plasticizing and melting cylinder 411 (hereinafter also referred to as a heating cylinder), a hopper 412 that supplies resin pellets into the heating cylinder 411, and a heating cylinder 411. A motor 414 that rotates the screw 413, a cooling jacket 415, a die 416 that pushes out the molten resin while reducing the thickness of the molten resin in a fan shape, and a cooling roll 417. As the screw 413, a single screw having a vent structure part 413a serving as a decompression part was used.

  The structure / method of the extrusion die 416 is arbitrary and can be set as appropriate depending on the shape, use, etc. of the molded product to be produced. In this example, a T-die for film formation was used as the extrusion die 416. Further, in the molding apparatus 400 of this example, the resin film 501 pushed out from the T die 416 is wound up by the cooling roll 417 or the like. In this embodiment, the gap t at the die extrusion port of the T die 416 was set to 0.5 mm.

  Further, in the molding apparatus 400 of this example, as shown in FIG. 18, the carbon dioxide inlet 411a is provided in the vicinity of the vent mechanism portion 413a of the single screw 413 where the molten resin is decompressed. Further, in the molding apparatus 400 of this example, as shown in FIG. 18, a monitor for measuring the internal pressure of the resin includes a connection part (monitor 418) between the heating cylinder 411 and the cooling jacket 415, and the inside of the cooling jacket 415 ( Monitor 419).

  As shown in FIG. 18, the carbon dioxide supply unit 402 mainly includes a carbon dioxide cylinder 441, a syringe pump 442, a dissolution tank 443, a back pressure valve 444, a valve 445, a pressure gauge 446, and a configuration thereof. It is comprised from piping 447 which connects an element. Further, as shown in FIG. 18, the downstream side (secondary side) of the valve 445 is connected to a carbon dioxide inlet 411a of the heating cylinder 411 via a pipe 447, and the molten resin inside the heating cylinder 411 It is in circulation with the channel. In addition, the introduction | transduction location of a carbon dioxide is not limited to this, If it is the area | region from the screw 413 to the T-die 416, it can provide in arbitrary locations.

  Further, as shown in FIG. 18, the carbon dioxide discharge unit 403 mainly includes an extraction container 461 for discharging carbon dioxide, a back pressure valve 462, a pressure gauge 463, and a pipe 464 that connects these components. Consists of Further, as shown in FIG. 18, the upstream side (primary side) of the back pressure valve 462 is connected to the carbon dioxide discharge port 415 a of the cooling jacket 415 through a pipe 464, and the molten resin inside the cooling jacket 415 It is in circulation with the channel.

  In the extrusion molding machine unit 401 of this embodiment, the mechanisms such as the screw 413, the heating cylinder 411, the die 416, and the like can have the same forms as the mechanisms of a known extrusion molding machine.

[Resin Film Molding Method] Next, a resin film molding method in this example will be described with reference to FIGS. 18 and 19. FIG. 19 shows a manufacturing process of the plastic part of the seventh embodiment.

  First, a sufficient amount of pellets of resin material (polycarbonate) is supplied to the hopper 412 of the extrusion molding unit 401, and the screw 413 is rotated by the motor 414 to plasticize and melt the resin material, and the molten resin is supplied to the heating cylinder 411. It was sent to the tip (step S51 in FIG. 19). At this time, the temperature of the heating cylinder 411 was adjusted to 280 ° C. by the band heater 420.

  Next, the fluorine compound was dissolved in the high-pressure carbon dioxide by flowing high-pressure carbon dioxide (high-pressure fluid) inside the dissolution tank 443 previously charged with the fluorine compound and the metal complex (step S52 in FIG. 19). Specifically, the fluorine compound and the metal complex were dissolved in high-pressure carbon dioxide as follows. First, the pressure of the liquid carbon dioxide supplied from the carbon dioxide cylinder 441 was increased and the pressure was adjusted by the syringe pump 442, and the pressure was adjusted so that the pressure gauge 46 became 15 MPa. The pressurized high-pressure carbon dioxide is temperature-controlled at 40 ° C., and flows into the dissolution tank 443 charged so that the fluorine compound and metal complex are supersaturated, and the fluorine compound and metal complex are dissolved in high-pressure carbon dioxide. I let you.

  Next, the valve 445 is opened, and high-pressure carbon dioxide in which a fluorine compound is dissolved is introduced into the vent structure portion 413a of the heating cylinder 411 through the pipe 447 and the introduction port 411a. The contact was allowed to permeate (step S53 in FIG. 19). At this time, high-pressure carbon dioxide in which a fluorine compound and a metal complex were dissolved was introduced at a constant flow while controlling the flow rate of high-pressure carbon dioxide with a syringe pump 442 and controlling the pressure of high-pressure carbon dioxide with a back pressure valve 444. At this time, the high-pressure carbon dioxide and the osmotic material (fluorine compound, metal complex) injected into the molten resin of the vent structure portion 413 a are kneaded into the resin by the rotation of the screw 413.

  Next, the molten resin was extruded from the heating cylinder 411 while adjusting the pressure of the molten resin in which high-pressure carbon dioxide, fluorine compound, and metal complex were kneaded so as to increase to 20 MPa on the display 418 of the internal pressure of the resin.

  Next, the molten resin extruded from the heating cylinder 411 was passed through the cooling jacket 415. The cooling jacket 415 is cooled to 200 ° C. by temperature-controlled water that flows through a cooling water channel 415 b provided inside the cooling jacket 415. Further, in the molding apparatus 400 of this example, as shown in FIG. 18, the cross-sectional area of the flow path of the molten resin inside the cooling jacket 415 is equal to the flow path of the molten resin at the connecting portion between the heating cylinder 411 and the cooling jacket 415. Since it is larger than the cross-sectional area, when the molten resin passes through the cooling jacket 415, the pressure is reduced simultaneously with cooling. In this example, when the molten resin passed through the cooling jacket 415, the resin internal pressure monitor 419 in the decompression section showed 10 MPa.

  Next, the molten resin extruded from the cooling jacket 415 passes through the T die 416, and the resin 501 extruded from the T die 416 is wound up by a cooling roll 417 or the like and continuously formed into a film (sheet) ( Step S104 in FIG. 19). In this example, the resin 501 was thinned by a stretching apparatus (not shown) to produce a resin film having a thickness of 0.1 mm. Thus, a resin film (plastic sheet) in which the fluorine compound and the metal complex were dispersed on the surface and inside was obtained.

  The surface roughness of the plastic molded product (resin film 501) of this example described above was measured with a stylus type surface roughness measuring device (manufactured by KLA-Tencor). The arithmetic average roughness (Ra) was 5 nm, and the ten-point average roughness (Rz) was 8 nm.

  Next, the fluorine film dispersed in the vicinity of the surface of the resin film 501 was removed using the high-pressure carbon dioxide as the solvent for the resin film 501 (step S55 in FIG. 19). In this example, a supercritical state temperature of 40 ° C. and a pressure of 15 MPa were used, and a cleaning process was performed for 30 minutes. By this step, fine holes were formed at the locations where the fluorine compound was removed, and fine irregularities were formed on the surface of the plastic molded product (resin film 501). In this example, the surface modification of the plastic molded product was performed as described above.

  As described above, in the surface modification method of the plastic molded product (resin film 501) of this example, since the fluorine compound different from the material of the resin film is removed from the resin film by the solvent, at least on the surface of the molded product. A resin molded product in which fine holes are formed is obtained. The size of the micropores can be controlled in the range from several nm order to micron order depending on the molecular weight of the fluorine compound and the conditions for extracting and removing the fluorine compound from the resin film.

  The surface roughness of the plastic molded product having fine holes formed on the surface produced as described above was measured in the same manner as in Example 1. As a result, the arithmetic average roughness (Ra) is 15 nm, the ten-point average roughness (Rz) is 130 nm, and the surface roughness is large compared to the plastic molded product before removing the fluorine compound, that is, after extrusion molding. became. This indicates that the fluorine compound dispersed on the surface of the resin film was removed and fine pores were formed. However, considering that the surface of the molded product is roughened by about several μm to several tens of μm in the etching process of chromic acid or permanganic acid performed in the conventional plating process, the plastic molded product whose surface is modified in this example Then, it turned out that favorable surface roughness (good smoothness) is obtained compared with the molded article roughened by the conventional etching process.

[Method for Forming Plating Film] Next, in this example, a plating film was formed on the plastic molded product from which the fluorine compound was removed in the same manner as in Example 2 (step S56 in FIG. 19).

  Next, the peel test using the tape similar to Example 1 was done with respect to the polymer molded article in which the plating film was formed on the said polymer. As a result, peeling of the plating film or the like was not confirmed.

  Moreover, when the surface roughness of the plating film formed in this example was measured with a stylus type surface roughness measuring device (manufactured by KLA-Tencor), the arithmetic average roughness (Ra) was 32.2 nm, the 10-point average. The roughness (Rz) is 115.4 nm, which is very small compared to the plating film (Ra ≒ several μm to several tens of μm) formed by the conventional plating method (etching method), and good surface roughness (good) Smoothness) was obtained. That is, in this example, a plastic molded product having an electroless plating film excellent in adhesion and smoothness formed on the surface could be obtained.

  Then, about 20 μm of conventional nickel electroplating was applied in the atmosphere, and a high temperature and high humidity (80 ° C., 90% Rh, 500 hr) test was performed. As a result, peeling and blistering of the metal film were not observed in all tests. Further, when a peel test with a tape was performed, peeling or the like did not occur. Similar results were obtained when 10 cycles of a high temperature test and a -40 ° C. to 85 ° C. heat cycle test were performed under conditions of a temperature of 150 ° C. and a standing time of 500 hours. That is, according to the plating film forming method of this example, it was found that not only the process can be simplified by a simple method, but also a metal film having high adhesion and smoothness can be formed on the polymer member. Table 3 summarizes the test results after plating in Example 7.

[Comparative Example 1]
In Comparative Example 1, injection molding, surface modification (supercritical carbon dioxide flow), and a plating film were formed by the same method as in Example 3 except that no fluorine compound was used.

  A peel test using the same tape as in Example 1 was performed on a polymer molded article having a plating film formed on the polymer. As a result, peeling of the plating film or the like was not confirmed.

  Moreover, when the surface roughness of the plating film formed in this example was measured with a stylus type surface roughness measuring device (manufactured by KLA-Tencor), the arithmetic average roughness (Ra) was 6.0 nm, ten points. The average roughness (Rz) is 23.7 nm, which is very small compared to the plating film (Ra≈several μm to several tens μm) formed by the conventional plating method (etching method), and has a good surface roughness. (Good smoothness) was obtained. That is, in this example, since the extraction is not performed in supercritical carbon dioxide, the smoothness of the substrate surface is maintained, and as a result, the surface roughness becomes very small.

  Then, about 20 μm of conventional nickel electroplating was applied in the atmosphere, and a high temperature and high humidity (80 ° C., 90% Rh, 500 hr) test was performed. As a result, blistering was observed in the metal film. In addition, when the high temperature test and 10 cycles of the heat cycle test of −40 ° C. to 85 ° C. were performed under the conditions of a temperature of 150 ° C. and a standing time of 500 hours, film swelling occurred similarly. That is, in this example, since the surface treatment was not performed by extracting the fluorine compound, it was found that the adhesion of the plating film was insufficient.

  In the surface modification method of the present invention, fine unevenness of submicron to nano-order can be formed on various types of plastics using high-pressure carbon dioxide. Therefore, for example, when the surface modification method of the present invention is used as an electroless plating pretreatment process, it is a low-cost and clean electroless plating pretreatment process.

  In the method for forming a metal film of the present invention, a metal film having excellent smoothness and adhesion can be formed without using a harmful etchant as in the conventional plating method and without questioning the plastic material. it can. Therefore, the metal film formation method of the present invention can be applied to all fields and is suitable as a low-cost and clean metal film formation method. Further, the method for forming a metal film of the present invention can be easily applied to a molded body having a large area and a complicated shape.

  Further, in the surface modification method of the present invention, the surface roughness of the plastic molded body can be made very small, and a highly adherent plating film can be formed. Therefore, for example, it is suitable as a method for forming a metal film such as a reflector that requires high reflectance, and a metal film such as a high-frequency electric circuit or antenna that requires good electrical characteristics.

1 is a cross-sectional view schematically showing a plastic part molded in Example 1. FIG. FIG. 2 shows an injection molding apparatus for forming the plastic molded body in FIG. FIG. 3 is a partially enlarged view of the injection molding apparatus of FIG. FIG. 3A schematically shows the state immediately after the start of injection, and FIG. 3B schematically shows the state at the end of injection. FIG. 4 shows a manufacturing process of the plastic part of FIG. FIG. 5 is an AFM observation image of the surface of the plastic molded body. FIG. 5A shows the surface of the plastic molded body that has not been cleaned with supercritical carbon dioxide, and FIG. 5B shows the surface of the plastic molded body that has been cleaned with supercritical carbon dioxide. FIG. 6 shows an electroless plating apparatus. FIG. 7 shows a manufacturing process of the plastic part of the third embodiment. FIG. 8 shows a schematic configuration of the sandwich injection molding apparatus of the fourth embodiment. FIG. 9 is an enlarged view of a main part at the time of plasticizing measurement in the first plasticizing cylinder in the sandwich injection molding apparatus of FIG. FIG. 10 is an enlarged view of a main part at the time of exhausting carbon dioxide gasified from the first plasticizing cylinder in the sandwich injection molding apparatus of FIG. FIG. 11 is an enlarged view of a main part at the time of injection by the first plasticizing cylinder in the sandwich injection molding apparatus of FIG. FIG. 12 is an enlarged view of a main part when the injection by the first plasticizing cylinder is completed in the sandwich injection molding apparatus of FIG. FIG. 13 is an enlarged view of a main part at the time of injection by the second plasticizing cylinder in the sandwich injection molding apparatus of FIG. FIG. 14 is an enlarged view of a main part when the injection by the second plasticizing cylinder is completed in the sandwich injection molding apparatus of FIG. FIG. 15 shows a manufacturing process of the plastic part of the fourth embodiment. FIG. 16 shows an electroless plating apparatus of Example 4. FIG. 17 shows a manufacturing process of the plastic part of the fifth embodiment. FIG. 18 shows a schematic configuration of the extrusion molding apparatus of Example 7. FIG. 19 shows a manufacturing process of the plastic part of the seventh embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plastic part 2 Plastic molded object 3 Metal film 101 Molding die 105 Plasticizing cylinder (heating cylinder)
105A Flow front part

Claims (20)

A method for modifying the surface of a plastic molded body formed by melting plastic and injecting it into a molding die,
Contacting high pressure carbon dioxide in which a fluorine compound is dissolved with molten plastic;
Injecting and molding the molten plastic in contact with the high-pressure carbon dioxide into the molding die; and
Dissolving the fluorine compound impregnated in the surface portion of the plastic molded body obtained in the molding step with high-pressure carbon dioxide, and removing the fluorine compound from the surface portion of the plastic molded body;
A surface modification method comprising:   2. The surface modification method according to claim 1, wherein the high-pressure carbon dioxide in which the fluorine compound is dissolved comes into contact with a portion of the molten plastic that is first injected into the molding die.   2. The surface modification method according to claim 1, wherein the high-pressure carbon dioxide in which the fluorine compound is dissolved is introduced into a flow front portion of a heating cylinder that houses the molten plastic injected into the molding die. . A method for modifying the surface of a plastic molded body formed by melting plastic and injecting it into a molding die,
Melting the plastic pellets in which the fluorine compound is dispersed;
Injecting the molten pellets into the molding die and molding;
Dissolving the fluorine compound impregnated in the surface portion of the plastic molded body obtained by the injection molding with high-pressure carbon dioxide, and removing the fluorine compound from the surface portion of the plastic molded body;
A surface modification method comprising: A method for modifying the surface of a plastic molded body formed by extruding a plastic material from an extrusion mold,
Contacting the plastic material with high-pressure carbon dioxide in which a fluorine compound is dissolved;
Molding the plastic material in contact with the high pressure carbon dioxide by extruding from the extrusion mold;
Dissolving the fluorine compound impregnated in the surface portion of the plastic molded body obtained by the molding with high-pressure carbon dioxide, and removing the fluorine compound from the surface portion of the plastic molded body;
A surface modification method comprising: A method for modifying the surface of a plastic molded body formed by extruding a plastic material from an extrusion mold,
Heating the plastic pellets in which the fluorine compound is dispersed;
Extruding and molding the heated plastic from the extrusion mold;
Dissolving the fluorine compound impregnated in the surface portion of the plastic molded body obtained by the molding with high-pressure carbon dioxide, and removing the fluorine compound from the surface portion of the plastic molded body;
A surface modification method comprising: The surface modification method according to claim 1, wherein the plastic is a thermoplastic resin.   8. The pressure of the high-pressure carbon dioxide when the fluorine compound impregnated on the surface portion of the plastic molded body is dissolved with high-pressure carbon dioxide is 5 MPa to 25 MPa. The surface modification method according to one item.   The surface modification method according to claim 7 or 8, wherein the fluorine compound has a boiling point of 150 ° C or higher.   The molecular weight of the said fluorine compound is 500-15000, The surface modification method of Claim 9 characterized by the above-mentioned. A method for forming a metal film on a plastic molded body formed by the surface modification method according to any one of claims 1 to 10,
A method of forming a metal film, comprising the step of forming a metal film on the surface of the plastic molded body after removing the fluorine compound. A method for forming a metal film on a plastic molded body formed by the surface modification method according to claim 1,
A metal film is formed on the surface of the plastic molded body by dissolving a plating solution in the high-pressure carbon dioxide when the fluorine compound impregnated on the surface of the plastic molded body is dissolved. Forming a metal film. Furthermore, before forming the metal film, the step of dispersing the plating catalyst core in the plastic molded body,
13. The method for forming a metal film according to claim 11, wherein the metal film is grown from the plating catalyst nucleus.   The plating molded core is dispersed in the plastic molded body before forming the metal film by contacting the plastic molded body after removing the fluorine compound with high-pressure carbon dioxide melted with the plating catalyst core. The method for forming a metal film according to claim 13.   By dissolving the plating catalyst nucleus in the high-pressure carbon dioxide that is in contact with the plastic molten resin in order to disperse the fluorine compound in the plastic molded body, the plastic molded body is formed before the metal film is formed. 14. The method for forming a metal film according to claim 13, wherein the plating catalyst nucleus is dispersed.   16. The method for forming a metal film according to claim 15, wherein the plating catalyst nucleus is a metal complex containing fluorine.   A plastic part comprising a plastic molded body having a porous structure in which a fluorine compound is dispersed inside and a plurality of fine holes are formed in a surface portion.   18. The plastic part according to claim 17, further comprising a plating catalyst core dispersed in the plastic molded body.   The plastic part according to claim 17 or 18, wherein the micropore has a size of submicron to nano-order.   The plastic part according to any one of claims 17 to 19, further comprising a metal film formed on the surface of the plastic molded body so as to enter the fine hole.