JP4092364B1 - Method for forming plating film and electroless plating solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive electroless plating film having high adhesion strength on the surface of various kinds of polymer members.
A method of forming a plating film on a polymer member, comprising preparing a polymer member impregnated with a metal substance serving as a plating catalyst core inside the surface, and an electroless plating solution containing pressurized carbon dioxide and alcohol The above-mentioned problem is solved by providing a method for forming a plating film, which comprises contacting a polymer member with a polymer member to form a plating film on the polymer member.
[Selection] Figure 5

Description

  The present invention relates to a method of forming a plating film on a polymer member and an electroless plating solution used by the method.

  Conventionally, an electroless plating method is known as a method for forming a metal film on the surface of a polymer member (polymer molded product) at low cost. However, in the electroless plating method, in order to ensure the adhesion of the plating film, the surface of the polymer member is etched using an oxidizing agent having a large environmental load such as hexavalent chromic acid or permanganic acid as a pretreatment of the electroless plating. It is necessary to roughen the surface of the polymer member. In addition, polymers immersed in such an etching solution, that is, polymers to which electroless plating can be applied are limited to polymers such as ABS. This is because ABS contains a butadiene rubber component, and this component is selectively eroded by the etching solution to form irregularities on the surface, whereas other polymers are selective to such an etching solution. This is because there are few components that are oxidized to the surface and it is difficult to form irregularities on the surface. Therefore, for a polycarbonate or the like which is a polymer other than ABS, a plating grade in which ABS or an elastomer is mixed to enable electroless plating is commercially available. However, with such plating grade polymers, deterioration of physical properties such as a decrease in heat resistance of the main material is inevitable, and it has been difficult to apply to molded products that require heat resistance.

  Conventionally, a technique for applying a surface modification method using pressurized carbon dioxide such as supercritical carbon dioxide to plating pretreatment has been proposed. In the surface modification method using pressurized carbon dioxide, the functional material is dissolved in the pressurized carbon dioxide, and the functional material is polymerized by bringing the pressurized carbon dioxide dissolved in the functional material material into contact with the polymer member. The polymer member surface is highly functionalized (modified) by penetrating the inside of the member surface. For example, the present inventors have disclosed a method of performing a surface modification treatment using pressurized carbon dioxide simultaneously with injection molding to make the surface of a polymer molded product highly functional (for example, see Patent Document 1). .

  Patent Document 1 discloses the following surface modification method. First, after plasticizing and weighing the resin in a heating (plasticizing) cylinder of an injection molding machine, the screw in the heating cylinder is sucked back and moved backward. Next, a functional organic material such as pressurized carbon dioxide in a supercritical state and a metal complex dissolved in the screw front part (flow front part) of the molten resin that became negative pressure (reduced pressure) due to the suck back of the screw Is introduced. By this operation, the pressurized carbon dioxide and the functional material can be infiltrated into the molten resin in the front portion of the screw. Next, the molten resin is injection-filled into a mold. At this time, the molten resin in the front portion of the screw infiltrated with the functional material is first injected into the mold, and then the molten resin in which the functional material is hardly infiltrated is injected and filled. When the molten resin in the front part of the screw infiltrated with the functional material is injected, the molten resin in the front part of the screw is pulled by the mold surface due to 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 the surface modification method described in Patent Document 1, a polymer molded article in which a functional material is impregnated (surface-modified by the functional material) is produced inside the surface of the polymer molded article. By using a metal complex or the like as a plating catalyst as a functional material, a polymer molded product impregnated with the plating catalyst on the surface can be obtained, so there is no need to roughen the surface with an etching solution as in the conventional plating pretreatment method. An injection-molded product that can be electrolessly plated can be obtained.

  Furthermore, conventionally, a method of performing electroless plating using an electroless plating solution containing supercritical carbon dioxide has been disclosed (for example, Patent Document 2 and Non-Patent Document 1). In these documents, an electroless plating solution and supercritical carbon dioxide are dissolved using a surfactant, and an emulsion (emulsion state) is formed by stirring to cause a plating reaction in the emulsion. A method is disclosed. Usually, in electroplating or electroless plating, hydrogen gas generated during the plating reaction stays on the surface of the object to be plated, causing pinholes in the plating film. However, when an electroless plating solution containing supercritical carbon dioxide is used as in the electroless plating method disclosed in the above-mentioned document, supercritical carbon dioxide dissolves hydrogen, so it is generated during the plating reaction. It is said that the hydrogen that is removed is removed, so that a pinhole is hardly generated and an electroless plating film having high hardness is obtained. In Patent Document 2, although a plating process for a metal substrate is disclosed, a plating process for a polymer member is not disclosed.

Japanese Patent No. 3696878 Japanese Patent No. 3571627 Surface technology Vol. 56, no. 2, P83 (2005)

  As described above, in the conventional resin plating method, it is necessary to perform a pretreatment with a large environmental load, and the selectivity of the polymer material is also narrow.

  Further, when metal fine particles serving as a plating catalyst are infiltrated into the surface of the polymer member using the surface modification method of the polymer member using pressurized carbon dioxide such as supercritical fluid described in Patent Document 1, As described above, a polymer member having metal fine particles serving as a plating catalyst on the surface and inside is obtained. However, when electroless plating is applied to such a polymer member, only the metal fine particles present on the outermost surface of the polymer member contribute to the catalyst core of the electroless plating, and the metal fine particles present inside the polymer member. Is uneconomical because it is an excessive catalyst core. In addition, when a plating film is formed on a polymer member obtained using the technique described in Patent Document 1, the surface of the polymer member is not roughened, so that it is difficult to obtain a physical anchor effect of the plating film. There was a problem that it was difficult to obtain strong adhesion of the molded product.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for forming an electroless plating film having a low adhesion and high adhesion strength on the surface of a polymer member. is there.

  According to a first aspect of the present invention, there is provided a method of forming a plating film on a polymer member, comprising preparing a polymer member impregnated with a metal substance that serves as a plating catalyst nucleus inside the surface, There is provided a method for forming a plating film, which comprises contacting an electroless plating solution containing alcohol with the polymer member to form a plating film on the polymer member.

As used herein, “pressurized carbon dioxide” refers to pressurized carbon dioxide. Note that “pressurized carbon dioxide” here means not only supercritical carbon dioxide but also pressurized liquid carbon dioxide and pressurized carbon dioxide gas. The pressure of pressurized carbon dioxide includes not only carbon dioxide pressurized to a critical point (supercritical state) or higher, but also carbon dioxide pressurized at a pressure lower than the critical point. More specifically, in the present invention, a pressurized carbon dioxide having a temperature and pressure such that the density of carbon dioxide is in the following range so that the electroless plating solution and the pressurized carbon dioxide are easily compatible. It is desirable to be. The preferred range of density of the pressurized carbon ^{dioxide, 0.10g / cm 3 ~0.99g / cm} 3, more preferably ^{0.40g / cm 3 ~0.99g / cm 3} . When the density of the pressurized carbon dioxide is lower than this range, the compatibility with the electroless plating solution is lowered, and the permeability to the polymer member is also lowered. Further, when the density of the pressurized carbon dioxide is higher than the above range, the pressure of the pressurized carbon dioxide becomes very high (for example, a pressure of 30 MPa or more at a temperature of 10 ° C., a pressure of 40 MPa or more at a temperature of 20 ° C.), and a mass production apparatus. Becomes expensive.

  In order to obtain the density of the pressurized carbon dioxide, it is desirable that the temperature of the carbon dioxide is in the range of 10 ° C. to 110 ° C. and the pressure is in the range of 5 MPa to 25 MPa. In particular, the pressurized carbon dioxide is desirably supercritical carbon dioxide having a temperature of 31 ° C. or higher and a pressure of 7.38 MPa or higher. In the supercritical state, not only the density of pressurized carbon dioxide increases, but also the surface tension becomes zero, so that the permeability of the plating solution into the polymer member is improved. If the temperature is 10 ° C. or lower, the plating reaction is difficult to occur, and if the temperature is 110 ° C. or higher, the plating solution is decomposed. Regarding the pressure, if the pressure is 5 MPa or less, the density of the pressurized carbon dioxide is greatly reduced, and if the pressure is 25 MPa or more, a burden is imposed on the industrialization apparatus.

  The “electroless plating method” as used herein refers to a method of depositing a metal film using a reducing agent on the surface of a substrate having catalytic activity without using an external power source. Further, the “inside surface” of the polymer member here means not only the inside of the polymer member but also the outermost surface.

  When the present inventors diligently examined the electroless plating method using the electroless plating solution containing supercritical carbon dioxide disclosed in Patent Document 2 and Non-Patent Document 1, etc., a metallic substance ( For example, by simply contacting a polymer member impregnated with metal fine particles) with an electroless plating solution containing pressurized carbon dioxide, an electroless plating film is formed on the surface of the polymer member, but sufficient adhesion is achieved. It was found difficult to form a plating film having According to the verification experiment of the present inventors, in this case, the plating film grows mainly using the metal substance present on the outermost surface of the polymer member as a catalyst nucleus, and the physical anchor effect of the plating film is obtained. I found it difficult. Therefore, it is considered that the strong adhesion between the plating film and the molded product cannot be obtained simply by bringing the electroless plating solution into contact with the polymer member together with the pressurized carbon dioxide.

  Further, according to the study of the present inventor, in the electroless plating method using the electroless plating solution containing supercritical carbon dioxide disclosed in Patent Document 2 and Non-Patent Document 1, etc., carbon dioxide and aqueous solution in a high pressure state are used. It was found that the electroless plating solution is not compatible with the electroless plating solution even if a surfactant is used, and the stirring effect needs to be increased. Specifically, it has been found that it is necessary to use a stirrer with high stirring torque or a high-pressure vessel with a shallow bottom. That is, in order to obtain a stable emulsion by uniformly mixing the electroless plating solution and the pressurized carbon dioxide, it has been found that there are large restrictions on the shape of the high-pressure vessel, the stirrer, etc. and the rotation speed of the stirrer.

  The present invention has been made to solve the above-described problems. In the plating film forming method of the present invention, the plating treatment of the polymer member is performed using not only pressurized carbon dioxide but also an electroless plating solution containing alcohol. I do. According to the verification experiment of the present inventors, the electroless plating solution is mainly composed of water. Furthermore, the electroless plating solution and the pressurized carbon dioxide are stirred by mixing alcohol with the electroless plating solution. Even without this, it has been found that carbon dioxide in a high pressure state and the plating solution can be mixed stably and easily. This is considered to be because alcohol is easily compatible with high-pressure carbon dioxide. Therefore, normally, when preparing an electroless plating solution, the stock solution containing metal ions, a reducing agent, etc. is diluted with water according to, for example, the component ratio recommended by the manufacturer, and the plating solution is bathed. In this plating film forming method, a stable mixed solution in which the electroless plating solution and the pressurized carbon dioxide are uniformly mixed can be prepared by further mixing alcohol with water at an arbitrary ratio.

  In the plating film forming method of the present invention, since the electroless plating solution and the pressurized carbon dioxide are uniformly mixed via alcohol, such a mixed solvent becomes a plating catalyst nucleus inside the surface. When contacted with a polymer member impregnated with a metal material containing Pd, Ni, Pt, Cu, etc., the electroless plating solution easily penetrates into the polymer member together with the pressurized carbon dioxide, and the metal material inside the polymer member The plating film can be grown using the catalyst nucleus.

  As described above, in the plating film forming method of the present invention, the plating film grows using the metal substance existing inside the polymer member as a catalyst nucleus, so that the plating film is bitten into the inside of the polymer member. Formed. Therefore, in the method for forming a plating film of the present invention, it is not necessary to roughen the surface of the polymer member by etching as in the conventional electroless plating method. A plating film having excellent adhesion can be easily formed on various types of polymer members. Further, in the method for forming a plating film of the present invention, the surface of the polymer member is not roughened as in the conventional electroless plating method, so that a plating film having a very small surface roughness (nano order) can be formed. .

  In addition, although the volume ratio of the alcohol with respect to water is arbitrary, it is desirable to be in the range of 10 to 80%. More desirably, it is 30 to 60% of range. When the volume ratio of alcohol is less than 10%, it becomes difficult to obtain a stable mixed solution, and the permeability of the electroless plating solution to the polymer member also decreases. Moreover, when the volume ratio of alcohol is larger than 80% (when there are too many alcohol components), for example, an organic solvent such as ethanol is insoluble in nickel sulfate used for nickel-phosphorus plating, so the bath may not be stable.

  In addition, 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 nickel phosphorus plating in which the plating reaction is about 60 ° C. or higher, it is desirable to use an alcohol having a boiling point higher than the reaction processing temperature. When alcohol having a boiling point lower than the treatment temperature is used, the boiling point of the alcohol is lowered and does not boil in a pressurized carbon dioxide atmosphere, but the alcohol volatilizes and plating at atmospheric pressure immediately after exhausting the carbon dioxide. The bath becomes unstable.

  In the method for forming a plated film according to the present invention, the polymer member is prepared using a molding machine, and the polymer member is prepared by pressing the metal material in the molten resin of the polymer member in the molding machine. It is preferable to include introducing carbon dioxide and molding the molten resin into which the metal substance is introduced.

In the plating film forming method of the present invention, the polymer member may have a plating film forming surface that is inert to the electroless plating solution under atmospheric pressure .

  According to the study by the present inventors, when a metal substance is present on the plating film forming surface of the polymer member at a concentration that causes a plating reaction under atmospheric pressure, the electroless plating solution may be contained inside the polymer member depending on the plating conditions. It has been found that a plating reaction may occur in the surface layer before penetrating into the polymer, making it difficult for the plating film to grow inside the polymer. The “plating film forming surface” of the polymer member in the present specification means the surface of the polymer member on which the plating film is formed.

  Accordingly, a polymer member having a plating film forming surface in a surface state in which a metal substance containing Pd, Ni, Pt, Cu, or the like serving as a plating catalyst nucleus is present and an electroless plating reaction does not occur under atmospheric pressure. If the prepared electroless plating solution containing carbon dioxide and alcohol is brought into contact with the polymer member having such a plating film forming surface, the concentration of the metal substance on the plating film forming surface is sufficiently low (under atmospheric pressure). Since it is inert to the electroless plating solution), the plating film does not grow on the surface where the plating film is formed, and the electroless plating solution penetrates into the polymer. When the electroless plating solution penetrates into a region where the concentration of the metal substance inside the polymer member is high, the plating reaction starts from that region. Thereafter, the plating film grows from the inside of the polymer toward the surface by the autocatalytic action of a metal substance such as nickel phosphorus plating.

  As described above, when a polymer member having a plating film forming surface in a surface state in which a metal substance serving as a plating catalyst core is present inside and an electroless plating reaction does not occur under atmospheric pressure is surely provided. In addition, the plating film can be grown from the inside of the polymer member. As used herein, the “surface state in which electroless plating reaction does not occur under atmospheric pressure” refers to a non-pressurized carbon dioxide that does not contain pressurized carbon dioxide in the atmosphere (under atmospheric pressure) and at a temperature at which plating reaction can occur. A state in which a plating film does not grow on the surface of a polymer member even when the polymer member is immersed in an electrolytic plating solution. More specifically, when the polymer member is kept in the electroless plating solution not containing pressurized carbon dioxide for 5 minutes or more in the atmosphere and in a temperature range where the plating reaction is possible, the entire surface of the polymer member is removed. A surface state where the plating film does not grow. Even if the metal substance serving as the catalyst nucleus exists on the surface of the polymer member, the plating reaction does not easily occur if the concentration is low.

  The following method is used as a method for producing a polymer member having a plating film forming surface in a surface state in which a metal substance serving as a plating catalyst core is present and an electroless plating reaction does not occur under atmospheric pressure. obtain.

  As a method for producing a polymer member having a plating film forming surface in which a metal substance is present and an electroless plating reaction does not occur under atmospheric pressure, for example, a molten state in a plasticizing screw of an injection molding machine or an extrusion molding machine In this resin, a metal material such as a metal complex is infiltrated with pressure carbon dioxide and kneaded, and a molten resin in which the metal material has permeated can be obtained by injection molding or extrusion molding into a mold or a die. At this time, for example, by injecting or extruding the molten resin into a mold or die at a low speed, the metal substance can penetrate into the inside of the resin, and the metal substance can be made difficult to float on the outermost surface of the molded product.

  Further, when the inventors further studied the surface modification method using supercritical carbon dioxide disclosed in Patent Document 1 described above, the surface using supercritical carbon dioxide disclosed in Patent Document 1 was obtained. In the reforming method, when the residence time of the metal complex becomes longer in the plasticizing cylinder, the metal complex is thermally decomposed and aggregated into metal fine particles. In this case, since the specific gravity of the metal fine particles becomes heavy, the inventors have found a phenomenon that even when a molten resin containing metal fine particles is injected, the metal fine particles on the outermost surface of the molded article are difficult to disperse due to the fountain flow phenomenon. That is, in the surface modification method disclosed in Patent Document 1, it has been found that the concentration of the metal substance decreases on the outermost surface of the obtained molded product depending on the molding conditions and the like. Therefore, in the surface modification method using supercritical carbon dioxide disclosed in Patent Document 1, by increasing the residence time of the metal complex in the plasticizing cylinder, metal fine particles (metal) on the outermost surface of the polymer member are obtained. The concentration of the substance) can be reduced to a surface state in which no electroless plating reaction occurs at atmospheric pressure.

  In order to produce a polymer member having a plating film-forming surface in which a metal substance is present and an electroless plating reaction does not occur under atmospheric pressure, as described later (see Example 1), a metal complex (metal After sufficiently infiltrating the substance) into the molten resin, the internal pressure of the resin may be reduced. By this treatment process, the metal complex is pyrolyzed at high temperature and high pressure to form a cluster to change the metal complex, which is an organic substance, into metal fine particles with a higher specific gravity, and to convert carbon dioxide into a low-pressure gas. . Even when the molten resin in such a state is injection-filled, the metal fine particles and the carbon dioxide gas are difficult to disperse on the surface of the polymer member (are difficult to be lifted).

  As described above, when molding a polymer member by infiltrating a metal material into the molten resin of the polymer member in the molding machine, by appropriately adjusting the molding conditions, the metal material is present inside and the atmospheric pressure is reduced. Thus, it is possible to produce a polymer member having a plating film forming surface on which electroless plating reaction does not occur. Even when polymer pellets pre-impregnated with a metal substance are used, a similar polymer member can be obtained by optimizing the molding conditions.

  As a method for producing a polymer member having a plating film forming surface in which a metal substance is present inside and an electroless plating reaction does not occur under atmospheric pressure, a metal substance is applied to the molten resin of the polymer member in the molding machine as described above. When the method of forming the polymer member by infiltration is used, the metal material that becomes the catalyst core of the plating film can be impregnated into the surface of the polymer member simultaneously with the formation of the polymer member, and the metal material is formed inside the surface. The impregnated polymer member can be produced by an easy and inexpensive process. As the molding method, an injection molding method (or sandwich molding method) or an extrusion molding method can be used.

  In addition to the method for adjusting the molding conditions described above, the plating film forming surface of the polymer member may be brought into a state in which electroless plating reaction does not occur under atmospheric pressure using the following method.

  First, using a molding machine or the like, a polymer member having a metal substance on the outermost surface at a concentration at which an electroless plating reaction occurs under atmospheric pressure is produced, and then a polymer member with an acid such as nitric acid, hydrochloric acid, or aqua regia. The metal material on the outermost surface may be washed to remove the plating material from the outermost surface of the polymer member (in a state inactive to the electroless plating solution).

  Further, as another method, using a molding machine or the like, a polymer member in which a metal substance is present on the outermost surface at a concentration at which an electroless plating reaction occurs at atmospheric pressure, and then containing pressurized carbon dioxide is included. A film made of a material that allows the electroless plating solution to pass through (for example, the same material as the polymer member) is formed on the plating film forming surface of the polymer member by a method such as casting, screen printing, spin coating, or dipping. Also good. In this method, a film without a metal substance is formed on the surface of the polymer member, so that no plating reaction occurs under atmospheric pressure. Examples of the material for forming such a film include thermoplastic resins such as polycarbonate, polymethyl methacrylate, cycloolefin, and polymers, thermosetting resins such as silicone, epoxy, and polyimide, and photocuring such as acrylic and epoxy resins. Resin, those porous materials, etc. can be used.

  In the method for forming a plating film of the present invention, the following method can be used as another method for reliably growing the plating film from the inside of the polymer member.

  In the method for forming a plating film of the present invention, forming the plating film on the polymer member includes contacting pressurized polymer dioxide with the polymer substrate to swell the vicinity of the surface of the polymer member, and the surface of the polymer member. It is preferable to include contacting the polymer member with an electroless plating solution containing pressurized carbon dioxide in a state where the vicinity is swollen.

  In this method, first, pressurized carbon dioxide is brought into contact with a polymer member impregnated with metal fine particles such as Pd, Ni, Pt, and Cu, which are plating catalyst nuclei, inside the surface. At this time, when the polymer member is formed of an amorphous material, the glass transition temperature is lowered and the vicinity of the surface is softened and swells. Further, when the polymer member is formed of a crystalline material, the intermolecular distance expands and swells in the vicinity of the surface even if it is not softened.

  Next, an electroless plating solution containing pressurized carbon dioxide (an electroless plating solution in a state where a plating reaction occurs (for example, a high temperature state)) is brought into contact with the polymer member in such a surface state. At this time, since the electroless plating solution is brought into contact with the vicinity of the surface of the polymer member being swollen, the electroless plating solution can be rapidly infiltrated into the inside of the polymer member together with the pressurized carbon dioxide. At this time, since the electroless plating solution mixed with pressurized carbon dioxide in a supercritical state or the like has a low surface tension, the electroless plating solution is more easily penetrated into the polymer member. As a result, the electroless plating solution reaches the metal material existing inside the polymer member, and the plating film grows using the metal material existing inside the polymer member as the catalyst nucleus. Also in this method, since the electroless plating solution can be rapidly infiltrated into the inside of the polymer member, the plating film grows using not only the surface of the polymer member but also a metal substance existing inside as a catalyst nucleus. Therefore, the plated film can be reliably grown from the inside of the polymer member also by this method.

  In the method for forming a plating film of the present invention, it is preferable that the metal substance includes any one of metal fine particles, a metal complex, and a modified metal complex. Specifically, the metal material impregnated inside the polymer member is fine particles (metal fine particles) made of any metal element of Pd, Pt, Cu, or Ni, or their organometallic complexes and modified products of metal complexes. It is desirable to be. In particular, metal complexes are desirable because they dissolve in pressurized carbon dioxide. Alternatively, the metal substance may be reduced to heat or the like after impregnating pressurized carbon dioxide in which the metal complex is dissolved into the polymer member to be converted into oxide or metal fine particles. Further, when palladium fine particles are used as the metal material, the metal fine particles function as catalyst nuclei for various electroless platings, which is preferable. Further, when nickel and copper are used as the metal fine particles, they act on catalyst nuclei for nickel plating and copper plating, respectively. In this case, since nickel and copper are less expensive than palladium, they are suitable depending on the situation (cost, etc.).

  In the plating film forming method of the present invention, the electroless plating solution may contain a surfactant. Thereby, the compatibility (affinity) of the pressurized carbon dioxide such as supercritical carbon dioxide and the electroless plating solution that is an aqueous solution can be further improved, and the formation of the emulsion can be promoted. In addition, the affinity of the plating solution for the polymer member can be improved.

  As the surfactant, it is desirable to select and use at least one of known nonionic, anionic, cationic and zwitterionic surfactants. In particular, it is desirable to use various surfactants that have been confirmed to be effective for forming an emulsion of supercritical carbon dioxide and water. For example, polyethylene oxide (PEO) -polypropylene oxide (PPO) block copolymer, ammonium carboxylate perfluoropolyether (PFPE), PEO-polybutylene oxide (PBO) block copolymer, octaethylene glycol monododecyl ether, etc. Can do.

  In the plating film forming method of the present invention, the plating film is preferably a nickel phosphorous film. In the electroless plating solution containing pressurized carbon dioxide in the present invention, the pH (hydrogen ion index) is lowered by containing carbon dioxide. That is, in the method for forming a plating film of the present invention, since the pH of the electroless plating solution varies depending on the carbon dioxide content, it is desirable to use an electroless plating solution that reacts stably in an acidic manner. Nickel phosphorous plating is more suitable because it can be plated over a wide range of pH 3-6.

  In the method for forming a plating film of the present invention, it is preferable that a minimum thin metal film is formed on the surface of the polymer member in a short time to ensure adhesion between the metal film and the polymer member. Thereby, it is possible to suppress the electroless plating solution from excessively penetrating into the polymer member, and it is possible to suppress deformation and alteration of the polymer member due to the electroless plating solution. When it is necessary to increase the thickness of the plating film, after forming the electroless plating film on the polymer member by the above method of the present invention, the conventional plating method (electroless plating method and / or Alternatively, a metal film having a desired film thickness can be laminated on the polymer member by applying an electrolytic plating method). According to this method, a plating film having both the reliability (adhesiveness) of the metal film and securing of physical properties such as conductivity can be obtained.

  In the method for forming a plating film of the present invention, it is preferable to prepare a polymer member in which an elution substance that can be dissolved in an electroless plating solution containing pressurized carbon dioxide is present inside the surface. In particular, the elution substance is preferably a mineral.

  According to the study of the present inventor, it has been found that a mixed solvent of pressurized carbon dioxide and water or alcohol has a strong oxidizing power and dissolves a substance that dissolves in an acidic solvent. In particular, the phenomenon becomes remarkable in a mixed solvent of an electroless plating solution and pressurized carbon dioxide, which is an acidic bath. Therefore, if you prepare a polymer member that contains a substance that dissolves in the electroless plating solution containing pressurized carbon dioxide inside the surface of the polymer member, contact the electroless plating solution containing pressurized carbon dioxide with the polymer member. By doing so, the eluted substance inside the surface of the polymer member dissolves into the electroless plating solution, and a void is formed in the region where the eluted substance was present. As a result, irregularities are formed on the surface of the polymer member, the physical anchor effect of the plating film on the surface of the polymer member is increased, and the adhesion of the plating film can be further improved. In this case, the surface of the polymer member can be etched without using a harmful organic solvent that has been used in the conventional plating method. Further, when a polymer member having an elution substance inside the surface of the polymer member is used, when the mixed solvent of pressurized carbon dioxide and electroless plating solution is brought into contact with the polymer member, the mixed solvent becomes the elution substance. It is also possible to obtain an effect that the polymer member can easily penetrate into the polymer member.

  As an elution substance that can be used in the plating film forming method of the present invention, any material can be used as long as it is a material that is dissolved and extracted in an electroless plating solution containing pressurized carbon dioxide. For example, minerals such as calcium carbonate and magnesium carbonate can be used. Since these minerals are conventionally used as a reinforcing agent for polymer members, they can be used without changing the polymer properties. These elution substances may be extracted from the polymer member during the plating reaction, or contacted with water, alcohol, or a mixed solvent of these and pressurized carbon dioxide before the plating reaction. It may be extracted in advance.

  Examples of substances that can be used as an eluent other than minerals include thermoplastic resins, low molecular weight substances thereof, and various elastomers (rubber elastic bodies) such as thermoplastic elastomers. By blending these resin substances into the base polymer, when the electroless plating solution containing pressurized carbon dioxide is brought into contact with the polymer member, it is possible to selectively swell the molten material portion, thereby Plating solution is easy to penetrate.

  In the plating film forming method of the present invention, when the plating film is formed on the polymer member, the metal container body and the electroless plating solution disposed inside the container body and containing the pressurized carbon dioxide It is preferable to use a processing container provided with an inner container made of an inert material, and to bring the polymer member into contact with the electroless plating solution containing the pressurized carbon dioxide in the inner container. It is preferable to use polytetrafluoroethylene, polyethyl ether ketone, liquid crystal polymer, or the like as a material for forming the inner container. By performing the plating process in such an inner container, effects such as that the high-pressure container and the inner wall of the inner container are not plated or corroded can be obtained.

  The material for forming the polymer member that can be used in the method for forming a plated film of the present invention is arbitrary, and a thermoplastic resin, a thermosetting resin, and an ultraviolet curable resin can be used. In particular, it is desirable to use a polymer member formed of a thermoplastic resin. The type of thermoplastic resin is arbitrary, and can be applied to either amorphous or crystalline. For example, synthetic fibers such as polyester, polypropylene, polyamide resin, polymethyl methacrylate, polycarbonate, amorphous polyolefin, polyetherimide, polyethylene terephthalate, liquid crystal polymer, ABS resin, polyamideimide, polyphthalamide, polyphenylene sulfide, polylactic acid Biodegradable plastics such as nylon resin, nylon resin and the like and composite materials thereof can be used. Further, a resin material in which various inorganic fillers such as glass fiber, carbon fiber, nanocarbon, and mineral are kneaded can also be used.

  Further, in the method for forming a plating film of the present invention, the form and production method of the polymer member are arbitrary. For example, a sheet or pipe produced by extrusion molding, or a polymer molded article produced by ultraviolet curing or injection molding is used. be able to. In consideration of industrial properties, it is preferable to use a polymer molded product obtained by injection molding with high continuous productivity.

According to a second aspect of the present invention, there is provided an electroless plating solution for use in a method for forming a plating film on a polymer member according to the first aspect of the present invention, further comprising a nickel phosphorus plating solution containing alcohol. An electroless plating solution in which the volume ratio of the alcohol in the nickel phosphorus plating solution is 30 to 60% is provided.

  The electroless plating solution of the present invention preferably further includes pressurized carbon dioxide.

  According to the method for forming a plating film of the present invention, a plating film grown from the inside of the polymer member can be formed on the polymer member, so that a plating film with better adhesion can be formed.

  Further, according to the method for forming a plating film of the present invention, since the electroless plating solution penetrates into the inside of the polymer member to cause a plating reaction, it is not necessary to roughen the surface of the polymer member as in the past, A plating film having excellent adhesion can be formed on all types of polymer members.

  According to the plating film forming method of the present invention, alcohol can be included in the electroless plating solution, and the compatibility between the electroless plating solution and the pressurized carbon dioxide can be improved.

  Hereinafter, embodiments of a method for forming a plating film on a polymer member of the present invention will be specifically described with reference to the drawings. However, the embodiments described below are preferred specific examples of the present invention. It is not limited to.

  In Example 1, a method of performing an electroless plating process in the same injection molding machine after injection molding of a polymer molded product (polymer member) using an injection molding machine will be described. In this example, an automobile headlight reflector was manufactured as a polymer member.

[Production equipment for polymer molded products]
A schematic configuration of the apparatus for producing a polymer molded product used in this example is shown in FIG. As shown in FIG. 1, the manufacturing apparatus 100 of the present embodiment mainly includes a vertical injection molding apparatus 103 including a mold, and supply of an electroless plating solution including pressurized carbon dioxide to the mold. It comprises an electroless plating apparatus unit 101 that controls discharge, and a surface reforming apparatus unit 102 that permeates pressurized carbon dioxide in which a metal complex is dissolved in a molten resin in a plasticizing cylinder of an injection molding apparatus unit 103.

  As shown in FIG. 1, the vertical injection molding apparatus unit 103 mainly includes a plasticizing and melting apparatus 110 that plasticizes and melts a resin for forming a polymer molded product, and a mold clamping apparatus 111 that opens and closes a mold. .

  The plasticizing and melting apparatus 110 mainly includes a plasticizing cylinder 52 with a built-in screw 51, a hopper 50, and a pressurized carbon dioxide introduction valve provided in the vicinity of a tip portion (flow front portion) in the plasticizing cylinder 52. 65. Further, a pressure sensor 40 for measuring the resin internal pressure was provided at a position facing the introduction valve 65 of the plasticizing cylinder 52. Poniphenylene sulfide (FZ-8600 Black manufactured by Dainippon Ink & Chemicals, Inc.) was used as a material for resin pellets (not shown) supplied from the hopper 50 into the plasticizing cylinder 52.

  The mold clamping device 111 is mainly composed of a fixed mold 53 and a movable mold 54. The movable mold 54 is connected to a movable platen 56 and a hydraulic mold clamping mechanism (not shown) connected to the movable mold 54 in conjunction with the drive. It is structured to open and close between the tie bars 55 of the book. Further, the movable mold 54 has a plating solution introduction path for supplying and discharging pressurized carbon dioxide and electroless plating solution to a cavity 104 defined between the movable mold 54 and the fixed mold 53. 61, 62 are formed. The plating solution introduction paths 61 and 62 are connected to a pipe 15 of an electroless plating apparatus unit 101 to be described later as shown in FIG. 1, and pressurized carbon dioxide and electroless plating liquid are cavities through the pipe 15. The structure is introduced into 104. The cavity 104 is sealed by fitting the spring-incorporated seal 17 provided on the outer diameter portion of the fixed mold 53 and the movable mold 54.

  As shown in FIG. 1, the surface reformer unit 102 mainly dissolves a liquid carbon dioxide cylinder 21, syringe pumps 20, 34, a filter 57, a back pressure valve 48, and a metal complex in pressurized carbon dioxide. It comprises a dissolving tank 35 and a pipe 80 connecting these components. Further, as shown in FIG. 1, the pipe 80 of the surface reforming unit 102 is connected to an introduction valve 65 of the plasticizing cylinder 52, and a pressure sensor 47 is provided in the pipe 80 near the introduction valve 65. Yes. In this example, a metal complex (hexafluoroacetylacetona palladium (II)) was used as a raw material for the metal fine particles (metal substance) charged in the dissolution tank 35.

  As shown in FIG. 1, the electroless plating apparatus unit 101 mainly includes a liquid carbon dioxide cylinder 21, a pump 19, a buffer tank 36, and a high-pressure vessel 10 that mixes an electroless plating solution and pressurized carbon dioxide. The circulation pump 90, the plating tank 11 for replenishing the electroless plating solution, the syringe pump 33, the recovery container 63 for recovering the electroless plating solution, the recovery tank 12, and the piping 15 connecting these components It consists of. Further, automatic valves 43 to 46 and 38 for controlling the flow of the pressurized carbon dioxide and the electroless plating solution are provided at predetermined positions of the pipe 15. Further, as shown in FIG. 1, the pipe 15 is connected to plating solution introduction paths 61 and 62 of the movable mold 54. In this example, a nickel phosphorus electroless plating solution containing 15% stock solution and 50 vol% alcohol (ethanol) was used as the electroless plating solution.

[Molding method of polymer molded product]
Next, a method for forming a polymer molded article in which metal fine particles are infiltrated into the surface will be described. In the present invention, the method of penetrating the metal complex into the resin is arbitrary, but in this embodiment, the metal complex was dissolved at the tip (flow front part) of the molten resin plasticized and measured in the plasticizing cylinder 52. Pressurized carbon dioxide was introduced.

  First, the metal complex was dissolved in ethanol in the dissolution tank 35, and the ethanol in which the metal complex was dissolved was increased to 15 MPa in the syringe pump 34. On the other hand, the liquid carbon dioxide cylinder 21 was supplied to the syringe pump 20 via the filter 57, and the liquid carbon dioxide pressure was increased to 15 MPa in the syringe pump 20. The pressurized carbon dioxide and ethanol in which the metal complex was dissolved were mixed in the pipe 80 (a pressurized mixed fluid was generated). When the pressurized mixed fluid was supplied to the plasticizing and melting apparatus 110, the supply pressure of the pressurized mixed fluid was controlled by the back pressure valve 48 so that the display of the pressure gauge 49 became 15 MPa. Further, the feeding of the pressurized mixed fluid of the ethanol solution and the pressurized carbon dioxide from both syringe pumps 20 and 34 was performed by switching the control of each syringe pump 20 and 34 from the pressure control to the flow rate control. Furthermore, when supplying the pressurized mixed fluid to the plasticizing and melting apparatus 110, the pressurized mixed fluid was supplied to the plasticizing and melting apparatus 110 while controlling the temperature in the pipe 80 to 50 ° C. by a heater (not shown).

  Next, a procedure for introducing the pressurized mixed fluid into the plasticizing and melting apparatus 110 will be described with reference to FIGS. 2A and 2B are enlarged cross-sectional views of the vicinity of the introduction valve 65 of the plasticizing and melting apparatus 110. FIG. First, while supplying resin pellets from the hopper 50, the screw 51 in the plasticizing cylinder 52 was rotated to measure plasticization of the resin. FIG. 2A shows a state in the vicinity of the introduction valve 65 when the plasticizing measurement is completed. At this time, as shown in FIG. 2A, the introduction pin 70 of the introduction valve 65 moves backward (moves to the left side in FIG. 2A), so that the pressurized mixed fluid 67 is fed to the molten resin 66. It is blocked from being introduced.

  Next, the screw 51 is sucked back (retracted) to reduce the internal pressure of the molten resin 66, and at the same time, both syringe pumps 20 and 34 are switched from pressure control to flow rate control. The pressure mixed fluid 67 was introduced into the molten resin 66 at the flow front portion in the plasticizing cylinder 52 through the introduction valve 65 while the flow rate was set to 1:10 by the above-described method (the state of FIG. 2B). ). A region 68 in FIG. 2B is a portion of the molten resin into which the pressurized mixed fluid 67 has permeated.

  In the introduction valve 65 of the plasticizing cylinder 52 of this embodiment, when the pressure difference between the molten resin 66 and the pressurized mixed fluid 67 becomes 5 MPa or more, the pressurized mixed fluid 67 is contained in the plasticizing cylinder 52. The structure is such that the molten resin 66 is introduced, and the principle of introduction of the pressurized mixed fluid 67 by the introduction valve 65 is as follows. When the screw 51 is sucked back after the plasticization measurement is completed, the molten resin 66 is decompressed and the density is lowered. When the pressure difference between the molten resin 66 and the pressurized mixed fluid 67 becomes 5 MPa or more, the pressure of the pressurized mixed fluid 67 overcomes the return force (elastic force) of the spring 71 in the introduction valve 65, and the introduction pin 70 advances to the molten resin 66 side, and the pressurized mixed fluid 67 is introduced into the molten resin 66. The pressurized mixed fluid 67 was introduced while monitoring the resin pressure and the pressure of the pressurized mixed fluid 67 with the pressure sensors 40 and 47, respectively.

  Subsequently, both syringe pumps 20 and 34 were stopped, and liquid feeding of the pressurized mixed fluid 67 was stopped. At the same time, the screw 51 was advanced to increase the resin pressure again to 20 MPa, and the introduction pin 70 was retracted (moved leftward in FIG. 2B). Thus, the introduction of the pressurized mixed fluid 67 was stopped, and the pressurized mixed fluid 67 and the molten resin 66 were made compatible.

  Subsequently, the resin pressure of the flow front part in the plasticizing cylinder 52 was maintained at 20 MPa to sufficiently infiltrate the metal complex into the resin, and then the internal pressure of the resin was reduced to 1 MPa. By this operation, many of the infiltrated metal complexes are thermally decomposed under high temperature and high pressure to form a clusterer, and the metal complex that is an organic substance changes to metal fine particles having a higher specific gravity. At this time, carbon dioxide becomes a low-pressure gas. By setting the flow front portion of the molten resin in such a state, when the skin layer is formed by injection filling described later, the metal fine particles and carbon dioxide gas are difficult to float on the surface of the skin layer (the outermost surface of the molded product). Become.

  Subsequently, after closing both the syringe pumps 20 and 34 in an automatic valve (not shown) in the pipe 80, the flow rate of the ethanol solution in which the pressurized carbon dioxide and the metal complex supplied to the plasticizing and melting apparatus 110 are dissolved is the syringe pump 20. , 34 was replenished. After that, the pressure control was switched to 15 MPa, and the system was kept waiting until the next shot was fed.

  Next, after the pressurized mixed fluid 67 is introduced into the molten resin 66 in the flow front part in the plasticizing cylinder 52, the mold is clamped by a hydraulic mold clamping mechanism (not shown) of the mold clamping device 111, and a temperature control circuit (not shown). The molten resin was injected and filled into the cavity 104 defined in the mold controlled in temperature by the illustration. At this time, the injection speed until injection filling is set to a low speed of 100 m / s, and the fine metal particles (Pd) are not dispersed at a sufficient concentration on the outermost surface of the polymer molded product, that is, no plating reaction is caused under atmospheric pressure. Injection molding was performed so as to disperse at a concentration. Next, the molded product was cooled and solidified (state shown in FIG. 3).

  When the molten resin is injection-molded into the mold, the molten resin 68 in the flow front portion that is injected first forms the skin of the injection-molded product by the fountain effect (fountain flow). That is, in this example, metal fine particles derived from the metal complex are dispersed in the vicinity of the flow front portion, and therefore, as shown in FIG. 3, the polymer 507 (inside the surface) of the polymer molded product 507 has a polymer impregnated with metal fine particles. A molded product 507 is obtained (step S11 in FIG. 5). In this example, in this way, the metal fine particles were dispersed in the skin layer 505 as the epidermis, and the polymer molded product 507 having almost no metal fine particles in the core layer 506 as the endothelium was obtained.

  A schematic cross-sectional view of the polymer molded product 507 of this example produced as described above is shown in FIG. In the skin layer 505 of the polymer molded product 507 of this example, as shown in FIG. 6, although the metal fine particles 550 (metal substance) are dispersed (existing) from the vicinity of the surface of the skin layer 505 to the inside, the skin layer 505 The concentration of the metal fine particles 550 in the vicinity of the outermost surface was lower than the concentration of the metal fine particles 550 inside the skin layer 505. In addition, the polymer molded product 507 (molded product in FIG. 6) immediately after molding in this example is actually 10% in an electroless plating solution (plating solution having a plating reaction temperature of 60 to 85 ° C.) at 70 ° C. at atmospheric pressure. When immersed for a minute, no plating film was formed on the surface of the polymer molded product 507. From this, in the polymer molded product 507 immediately after molding in this example, the outermost surface (plated film forming surface) is inactive to the electroless plating solution in a state where no plating reaction occurs under atmospheric pressure. It was confirmed.

[Method of forming plating film]
The polymer molded product 507 in which metal fine particles were dispersed inside the surface produced as described above was subjected to electroless plating in a mold as follows. During the electroless plating process, the temperature inside the mold was adjusted to 80 ° C.

  First, as shown in FIG. 4, the movable platen 56 and the movable mold 54 are moved backward by retreating the hydraulic mold clamping mechanism (not shown) of the mold clamping device 111 (downward in FIG. 4), so that the fixed mold is fixed. A gap 508 (cavity 508) was provided between the mold 53 and the polymer molded product 507.

  Next, an electroless plating solution containing pressurized carbon dioxide was introduced into the cavity 508 and brought into contact with the polymer molded product 507. Specifically, an electroless plating solution containing pressurized carbon dioxide was brought into contact with the polymer molded product 507 as follows. First, an electroless plating solution containing alcohol supplied from the plating tank 11 of the electroless plating apparatus unit 101 and a pressurized carbon dioxide of 15 MPa supplied from the buffer tank 36 in advance in the high-pressure vessel 10. : 3 was mixed (step S12 in FIG. 5). In the present invention, the mixing ratio of the pressurized carbon dioxide and the plating solution is preferably in the range of 1: 9 to 5: 5, and it is particularly desirable that the amount of the plating solution is large. At this time, the pressurized carbon dioxide and the electroless plating solution were dissolved in the high-pressure vessel 10 by driving the stirrer 16 and rotating the magnetic stirrer 6 at high speed. Subsequently, the automatic valve 43 was closed and the automatic valves 44 and 45 were opened.

  Next, the circulation pump 9 is operated, and an electroless plating solution containing pressurized carbon dioxide and alcohol is circulated through a circulation flow path including the high-pressure vessel 10, the pipe 15, and the cavity 508, so that the polymer molded product 507 is temporarily formed. An electroless plating solution was retained and contacted on the surface to form a plating film (nickel phosphorus film) (step S13 in FIG. 5). When the electroless plating solution containing pressurized carbon dioxide was circulated, the pressures in the cavities 508 and the circulation line 15 were the same by the pressure sensors 58 and 59. Further, replenishment of the electroless plating solution was performed at any time by increasing the pressure of the plating solution supplied from the plating tank 11 with the syringe pump 33 and feeding it simultaneously with the opening of the automatic valve 46.

  When the electroless plating solution containing pressurized carbon dioxide and alcohol is brought into contact with the polymer molded product 507 in the above-described process, the plating reaction does not occur on the outermost surface of the polymer molded product 507, and the pressurized carbon dioxide is contained. The electroless plating solution penetrates into the polymer molded product 507. Then, when the electroless plating solution penetrates to a region where the metal fine particles are dispersed at a concentration sufficient to cause a plating reaction inside the polymer molded product 507, the metal fine particles in the region are used as catalyst nuclei to form a plating film. Begins to grow. Thereafter, the plating film grows from the inside of the polymer member toward the surface by the autocatalytic action of the metal fine particles. That is, since the plating film formed on the polymer molded product 507 grows in a state of being bitten into the polymer molded product 507, a plating film having excellent adhesion is formed.

  Next, after forming a plating film on the polymer molded product 507 as described above, the electroless plating solution containing pressurized carbon dioxide is circulated through the collection vessel 63 from the circulation path of the electroless plating solution containing pressurized carbon dioxide. Exhausted from the recovery tank 12. Specifically, the automatic valves 44 and 45 were closed, and then the automatic valve 38 was opened, whereby the electroless plating solution containing pressurized carbon dioxide was discharged into the collection container 63. In the recovery container 63, the electroless plating solution containing the recovered pressurized carbon dioxide is separated into an aqueous solution (plating solution) and a high-pressure gas (carbon dioxide) by the principle of centrifugation. The plating solution can be recovered in the recovery tank 12 and reused. The gasified carbon dioxide is discharged from the upper part of the recovery container 63 and recovered in an exhaust duct (not shown).

  Next, the automatic valve 43 is opened for a certain period of time, and pressurized carbon dioxide is introduced into the gap 508 (cavity 508) between the fixed mold 53 and the polymer molded product 507, and the plating solution residue remaining in the cavity 508 is removed. It was discharged out of the mold together with the pressurized carbon dioxide. Next, when the internal pressure of the cavity 508 became zero as monitored by the pressure sensor 59, the mold was opened and the polymer molded product 507 was taken out.

  Next, the silver molded film 507 was laminated on the surface of the polymer molded product 507 by applying normal silver plating to the polymer molded product 507 taken out. In this example, a polymer molded product 507 having a plating film formed on the surface was obtained as described above.

  FIG. 7 shows a schematic cross-sectional view of a part of the polymer molded product 507 produced in this example. A nickel-phosphorus metal film 509 (plating film) grown in a mold is formed on one side of the polymer molded article 507 manufactured in this example. The nickel-phosphorus metal film 509 is formed of the polymer molded article 507. It grew from the inside (the permeation layer of the metal film 509 was formed). Further, a silver highly reflective film 510 was formed on the nickel-phosphorus metal film 509.

[Evaluation of plating film]
Next, the adhesion evaluation of a metal film was performed with respect to the polymer molded product 507 produced in this example. Specifically, high temperature and high humidity environment test (conditions: temperature 85 ° C., humidity 85% Rh, standing time 1000 hours), high temperature test under conditions of temperature 150 ° C. and standing time 500 hours, and −30 ° C. and 150 ° C. The heat shock test was performed 20 cycles between the temperatures. As a result, no decrease in the adhesion of the metal film was observed in all tests. Furthermore, when the surface roughness Ra of the polymer molded product 507 produced in this example was measured, Ra = 100 nm, which is equivalent to the surface roughness of the mold. That is, according to the plating film forming method of this example, the plating process can be performed simultaneously with the injection molding, the process can be simplified (the polymer member can be manufactured at a low cost), and the adhesiveness is also improved. It was found that a high and smooth metal film can be formed on a resin material having high heat resistance.

  In Example 2, a method of producing a polymer molded article (polymer member) in which metal fine particles are impregnated on the surface using a sandwich molding machine, and then subjecting the polymer molded article molded in another container to electroless plating treatment Will be described. In this example, a door knob for an automobile was produced as a polymer molded product.

  In this example, the type of functional material to be dissolved in pressurized carbon dioxide described later is arbitrary, but in this example, a metal complex was used. The type of the metal complex is arbitrary, but hexafluoroacetylacetonato palladium (II) having high solubility in carbon dioxide was used. Moreover, although the temperature and pressure conditions of the pressurized carbon dioxide introduced into the molten resin described later are arbitrary, in this embodiment, the temperature is 40 ° C. and the pressure is 10 MPa at which a supercritical state is achieved. In this example, polyamide 6 resin containing 30% glass fiber was used as a material for forming a polymer molded product.

[Sandwich molding equipment]
First, the sandwich molding apparatus used in the method for producing a polymer molded product (polymer member) of this example will be described. A schematic configuration of the molding apparatus used in this example is shown in FIG. As shown in FIG. 8, the molding apparatus 200 used in this example includes a sandwich molding machine unit 201, a pressurized fluid supply unit 202, and a pressurized fluid discharge unit 203.

  As shown in FIG. 8, the sandwich molding machine unit 201 mainly includes a first plasticizing and melting cylinder 220 (hereinafter, also referred to as a first heating cylinder) for forming a skin (surface layer) of a polymer molded product. , A second plasticizing and melting cylinder 224 (hereinafter also referred to as a second heating cylinder) for forming the core of the polymer molded product, and a molten resin outlet 220a of the first heating cylinder 220 and the second heating cylinder 224 And a nozzle part 218 connected to the first heating cylinder 220 and the second heating cylinder 224, and a mold 210 including a movable mold 211 and a fixed mold 212.

  In the nozzle part 218, as shown in FIG. 8, a rotary valve 219 for switching the injection path of the molten resin injected into the mold 210 is provided. In this example, as will be described later, by rotating a rotary valve 219, a molten resin injection path from the inside of the first heating cylinder 220 to the cavity 216 of the mold 210, and from the inside of the second heating cylinder 224 to the mold 210. The molten resin injection path to the cavity 216 is switched. Note that the cavity 216 of the mold 210 is a space defined by the fixed mold 212 and the movable mold 211 abutting against each other. In this example, as shown in FIG. 8, a mold 210 capable of simultaneously molding two door knobs for an automobile is used around a spool 217. The fixed mold 212 and the movable mold 211 are respectively fixed to the fixed platen 214 and the movable platen 213, and the mold 210 is opened and closed by driving the movable platen 213 by the mold clamping mechanism 215. Yes.

  In this example, as shown in FIG. 8, the first heating cylinder 220 includes an air-driven introduction cylinder 227 for introducing supercritical carbon dioxide in which the metal complex is dissolved into the molten resin, and supercritical dioxide. An air-driven discharge cylinder 229 for discharging carbon from the molten resin is provided. An introduction piston 228 and a discharge piston 230 are provided inside the introduction cylinder 227 and the discharge cylinder 229, respectively. Further, in this example, as the screw 221 (hereinafter also referred to as the first screw) in the first heating cylinder 220, as shown in FIG. 8, two vent portions for reducing the resin internal pressure are provided (in FIG. 8). First vent portion 223 and second vent portion 222). The introduction cylinder 227 and the discharge cylinder 229 are arranged in the vicinity of the first vent part 223 and the second vent part 222, respectively. As described above, the molding apparatus of this example is provided with a mechanism for gasifying supercritical carbon dioxide permeated into the molten resin and exhausting it before injection filling. On the other hand, the second heating cylinder 224 has the same structure as a conventional heating cylinder.

  As shown in FIG. 8, the pressurized fluid supply unit 202 mainly includes a liquid carbon dioxide cylinder 240, a known syringe pump 241, and a dissolution tank 242 for dissolving a metal complex in supercritical carbon dioxide. Each component is connected by a pipe 243. In the pressurized fluid supply unit 202, as shown in FIG. 8, valves 244 and 245 for controlling the flow of supercritical carbon dioxide are appropriately installed at predetermined locations, and the dissolution tank 242 is connected by a pipe 243. , And connected to the introduction cylinder 227 of the sandwich molding machine unit 201.

  As shown in FIG. 8, the pressurized fluid discharge unit 203 mainly includes a filter 254, a buffer container 253, a pressure reducing valve 252, and a vacuum pump 250, and each component is connected by a pipe 255. Yes. The filter 254 is connected to the discharge cylinder 229 of the sandwich molding machine unit 201 by a pipe 255.

  In addition, as a shaping | molding apparatus which can be used by a present Example, it is not limited to the example shown in FIG. The molding apparatus has a first plasticizing cylinder that forms the outer skin of the polymer molded article and a second plasticizing cylinder that forms the endothelium, and at least the first plasticizing cylinder was dissolved in pressurized carbon dioxide and the same. An apparatus having an arbitrary structure can be used as long as it has a function of introducing a functional material (metal complex).

[Production method of polymer molded product and formation method of plating film]
Next, the manufacturing method of the polymer molded product of this example is demonstrated, referring FIGS. In this example, a method for producing a polymer molded product will be described from the time when the previous sandwich molding is completed (the state shown in FIG. 9). Therefore, in FIG. 9, the molten resin injected from the second heating cylinder 224 during the previous molding remains in the resin flow path in the nozzle portion 218.

  First, a method for dissolving a metal complex in supercritical carbon dioxide will be described. First, the valve 244 was opened, and carbon dioxide was supplied from the liquid carbon dioxide cylinder 240 to the syringe pump 241. In the syringe pump 241, the supplied carbon dioxide is boosted to a predetermined pressure (10 MPa). Next, the valve 245 was opened, and pressurized liquid carbon dioxide was introduced into the dissolution tank 242 to dissolve the metal complex in the pressurized carbon dioxide (step S21 in FIG. 15). At this time, the temperature of the dissolution tank 242 was kept at 40 ° C., and the introduced pressurized liquid carbon dioxide was brought into a supercritical state. In this example, the metal complex was previously charged in the dissolution tank 242 so as to be supersaturated. Further, by introducing supercritical carbon dioxide into the dissolution tank 242, the piping region up to the introduction cylinder 227 was also pressurized. Note that the region from the dissolution tank 242 to the introduction cylinder 227 is held at a constant pressure by the syringe pump 241 except when supercritical carbon dioxide and organometallic complex in the plasticization metering step described later are introduced into the first heating cylinder 220. Controlled to be.

  Next, a sufficient amount of resin pellets (not shown) are supplied from the hopper 226 into the first heating cylinder 220, and the pellets (first thermoplastic resin: polyamide 6 resin) are plasticized by the rotation of the first screw 221. Melted. At the time of plasticization measurement, the internal pressure in front of the screw is increased by the rotation of the first screw 221 and the first screw 221 is retracted. Therefore, the first vent portion 223 of the first screw 221 provided at the lower portion of the introduction cylinder 227 is used. Then, the melted first thermoplastic resin (hereinafter also referred to as the first molten resin) is depressurized (about 7 MPa).

  Next, in a state where the first molten resin is decompressed, as shown in FIG. 9, the introduction piston 228 in the introduction cylinder 227 is raised, and the dissolution tank 242 of the pressurized fluid supply unit 202 and the first heating cylinder 220 are moved. The supercritical carbon dioxide in which the metal complex was dissolved was introduced into the first heating cylinder 220 and permeated into the first molten resin (step S22 in FIG. 15). During this infiltration process, the syringe pump 241 was switched to flow control, and a constant flow of supercritical carbon dioxide was injected into the first heating cylinder 220 for a fixed time. Also, most of the metal complex that has penetrated into the first molten resin is reduced to a plating catalyst (metal fine particles) by the heat of the first molten resin.

  Further, in this example, the supercritical carbon dioxide that has penetrated into the first molten resin during plasticization measurement is gasified and discharged from the inside of the first heating cylinder 220 to the pressurized fluid discharge unit 203 via the discharge cylinder 229. . Specifically, supercritical carbon dioxide was discharged as follows.

  First, at the time of plasticization measurement, the first molten resin was depressurized by the second vent portion 222 of the first screw 221, and the permeating supercritical carbon dioxide was depressurized below the critical pressure to be gasified. At this time, as shown in FIG. 9, the exhaust piston 230 provided in the discharge cylinder 229 is raised to circulate the inside of the first heating cylinder 220 and the pressurized fluid discharge portion 203, and the first heating cylinder 220. The carbon dioxide gasified in the second vent portion 222 was partially discharged to the pressurized fluid discharge portion 203 via the discharge cylinder 229. At this time, the sublimation-type metal complex kneaded in the high-temperature resin is thermally decomposed into fine metal particles as described above and is in an insoluble state in carbon dioxide. It will never be done. In this example, the residence time of the metal fine particles in the high temperature resin was extended (specifically, about 50 seconds), and the metal fine particles having a large specific gravity were dispersed in the molten resin. By adopting such a state, the metal fine particles are difficult to disperse on the outermost surface of the polymer molded product (skin layer) during injection filling described later.

  Next, after the carbon dioxide discharged to the high-pressure fluid discharge unit 203 was passed through the filter 254 and the buffer container 253, the pressure was reduced by the pressure reducing valve 252 so that the pressure gauge 251 showed 0 MPa, and the vacuum pump 250 exhausted the carbon dioxide. In this example, as described above, the first thermoplastic resin is plasticized and lightened in the first heating cylinder 220, while the metal complex is infiltrated into the first molten resin, and supercritical carbon dioxide is gasified to form the first. 1 discharged from the molten resin.

  In the above-described step of plasticizing and metering the first thermoplastic resin in the first heating cylinder 220, the resin pellets supplied from the hopper 226 are kneaded with the introduced supercritical carbon dioxide and the metal complex. However, since it is plasticized and melted, the supercritical carbon dioxide and the metal complex are uniformly diffused inside the first molten resin. In order to prevent the first molten resin pressurized in the first heating cylinder 220 from leaking from the tip of the nozzle part 218 into the mold 210 during plasticization measurement in the first heating cylinder 220, As shown in FIG. 9, the rotation of the rotary valve 219 is adjusted so that the inside of the second heating cylinder 224 and the injection passage in the nozzle portion 218 circulate through the passage in the rotary valve 219. The inside of 1 heating cylinder 220 and the inside of the nozzle part 218 were made not to distribute | circulate.

  Next, when the plasticization measurement of the first molten resin 260 in which the metal fine particles (and the metal complex) have permeated is completed with the first screw 221, the introduction piston 228 and the discharge cylinder in the introduction cylinder 227 are completed as shown in FIG. The discharge piston 230 in the 229 was lowered, and at the same time, the syringe pump 241 was switched from flow control to pressure control, and the introduction and exhaust of pressurized carbon dioxide were stopped.

  Next, as shown in FIG. 11, the inside of the first heating cylinder 220 and the injection flow path in the nozzle portion 218 are circulated, that is, the inside of the first heating cylinder 220 and the cavity 216 in the mold 210 are connected. The rotary valve 219 was rotated so as to circulate. Next, the first screw 221 of the first heating cylinder 220 is advanced to inject the plasticized and weighed first molten resin 260 into the spool and cavity 216 in the mold 210 (step S23 in FIG. 15: FIG. 11). And 12 states). The state of FIG. 12 represents a state immediately before the injection filling of the first molten resin 260 is completed. As shown in FIG. 12, in this example, the amount of the first molten resin 260 to be injected is the cavity The amount was adjusted so that the entire interior of 216 was not filled.

  On the other hand, in the second heating cylinder 224, during the injection of the first molten resin, resin pellets (second thermoplastic resin: polyamide 6 resin) are supplied into the second heating cylinder 224 from a hopper (not shown), Plasticization weighing was performed by rotating the screw 225. At this time, in the second heating cylinder 224, the resin pellets were plasticized and melted without introducing a metal complex (hereinafter, the resin plasticized and melted in the second heating cylinder 224 is also referred to as a second molten resin). Then, immediately before the injection filling of the first molten resin 260 was completed, the plasticization measurement of the second molten resin 261 was completed (state of FIG. 12). In this example, the same material is used for the first thermoplastic resin and the second thermoplastic resin, but the present invention is not limited to this, and the first thermoplastic resin and the second thermoplastic resin are formed of different materials. May be.

  Next, after the injection filling of the first molten resin is completed, as shown in FIG. 13, the second heating cylinder 224 and the injection flow path in the nozzle portion 218 are circulated, that is, the second heating cylinder. The rotary valve 219 was rotated so that the inside of the 224 and the cavity 216 in the mold 210 circulated. Next, the second screw 225 was advanced to inject the second molten resin 261 into the spool and cavity 216 in the mold 210 (step S24 in FIG. 15: state of FIG. 13). At this time, the first molten resin 260 previously filled in the cavity 216 is pushed to the mold surface defining the cavity 216 by the filling pressure of the second molten resin 261. As a result, as shown in FIG. 14, after completion of the injection of the second molten resin 261, the surface layer (outer skin) of the molded product has a layer of the first molten resin 260 in which metal fine particles (and metal complex) are dispersed. The core part which consists of the 2nd molten resin 261 which is formed and does not contain a metal microparticle is formed in the inside of a molded article.

  Next, after the injection-filled molten resin was cooled and solidified, the mold 210 was opened and the molded product (polymer substrate) was taken out. In this example, metal fine particles were dispersed inside the surface by the above-described sandwich molding to obtain a polymer molded product.

  In the same manner as in Example 1, the polymer molded product of this example molded as described above was placed in an electroless plating solution (plating solution having a plating reaction temperature of 60 to 85 ° C.) at 70 ° C. at atmospheric pressure. Although immersed for 10 minutes, no plating film was formed on the surface of the polymer molded product. That is, in the polymer molded product molded by the molding method of the present embodiment, the concentration of metal fine particles on the outermost surface (surface layer) is low, and the outermost surface of the polymer molded product does not cause a plating reaction under atmospheric pressure, That is, it was confirmed that it was inert to the electroless plating solution.

  Next, a plating film was formed by electroless plating on the surface of the polymer molded product of this example molded as described above (step S25 in FIG. 15). Specifically, a plating film was formed on the surface of the polymer molded product as follows. First, a high-pressure vessel having an inner container made of PTFE (polytetrafluoroethylene) is prepared, and a nickel phosphorus plating solution consisting of 15% stock solution, 50% alcohol (propanol) and 35% water is placed in the inner vessel. Then, the polymer molded product was inserted into the inner container and immersed in the electroless plating solution. At this time, the electroless plating solution, the high-pressure vessel, and the inner vessel were previously heated to 70 ° C. Next, pressurized carbon dioxide at 20 ° C. and 15 MPa is introduced into the high-pressure vessel and the inner vessel to dissolve the pressurized carbon dioxide in the electroless plating solution (an electroless plating solution containing pressurized carbon dioxide is polymer-molded). The product was kept in contact for 5 minutes and then decompressed. In this example, a nickel phosphorus metal film was formed on the entire surface of the polymer molded article as described above.

  Even in the above method, when the electroless plating solution containing pressurized carbon dioxide is brought into contact with the polymer molded product, the plating reaction does not occur on the outermost surface of the polymer molded product. The electrolytic plating solution penetrates into the polymer molded product. Then, when the electroless plating solution penetrates to a region where the metal fine particles are dispersed at a concentration sufficient to cause a plating reaction inside the polymer molded product, the metal fine particles in that region are used as catalyst nuclei, and the plating film is formed. Start growing. Thereafter, the plating film grows from the inside of the polymer toward the surface by the autocatalytic action of the metal fine particles. That is, also in the present embodiment, the plating film formed on the polymer molded product grows in a state of being bitten into the polymer molded product, so that a plating film having excellent adhesion is formed.

  Next, an electrolytic copper plating film having a thickness of 20 μm is formed on the surface of the above-described polymer molded article that has been subjected to electroless plating (a nickel phosphorus metal film is formed) by a conventional electrolytic plating method. A bright electrolytic nickel plating film having a thickness of 10 μm was formed thereon. Further, for the polymer molded article having a metal film formed on the surface produced in this example, the metal film adhesion evaluation test was conducted in the same manner as in Example 1. As in Example 1, No peeling of the metal film was observed, and no decrease in adhesion was observed.

  In Example 3, in the electroless plating process of Example 2, various volume ratios of alcohol in the electroless plating solution (nickel phosphorus plating solution) were changed to 5, 10, 30, 60, 80, and 90%. An electroless plating solution was prepared. Other than that was carried out similarly to Example 2, and formed the electroless-plated film on the surface of the polymer molded article (polymer member). In this example, the plating process was continuously performed a plurality of times with each electroless plating solution.

  As a result of the above treatment, in the electroless plating solution having an alcohol volume ratio of 80%, the plating film was formed on the front surface of the polymer molded product in the first treatment, but the plating film was hardly formed in the second treatment. It was. This is thought to be because when the amount of alcohol added is large, nickel sulfate is likely to precipitate from the nickel phosphorus plating solution, and as a result, the amount of nickel sulfate ions in the plating solution is insufficient and the plating bath is broken. . Actually, in the electroless plating solution having an alcohol volume ratio of 80%, nickel sulfate deposits were confirmed in the plating solution in the first and second treatments. However, as described above, it was found that in the electroless plating solution having an alcohol volume ratio of 80%, nickel plating precipitates are present in the plating solution, but the plating treatment can be performed at least once. .

  With the electroless plating solution having an alcohol volume ratio of 60%, a plating film could be formed after the second time. When the volume ratio of alcohol was 60%, the plating treatment time (time for forming a plating film on the entire surface of the polymer molded product) was 3 minutes.

  In the electroless plating solution in which the volume ratio of alcohol is 30%, the plating time is as long as 10 minutes. In addition, in the electroless plating solution having an alcohol volume ratio of 10%, the plating time was further increased to 30 minutes. This is considered to be because when the amount of alcohol decreases, the surface tension of the electroless plating solution increases and the penetration time of the electroless plating solution into the polymer molded product becomes longer. When the alcohol volume ratio was 10, 30 and 60%, the plating film was formed in the second and subsequent plating treatments.

  In addition, with the electroless plating solution having an alcohol volume ratio of 5%, a plating film was formed only on a part of the surface of the polymer molded product even when the plating treatment time was increased to 1 hr. In the electroless plating solution having an alcohol volume ratio of 90%, all nickel sulfate was precipitated, and no plating film was formed.

  In Example 4, a polyphenylene sulfide resin material in which fine particles of calcium carbonate (mineral) were mixed in advance was used as a material for forming a polymer molded article (polymer member). Calcium carbonate is a substance (eluting substance) that is dissolved and extracted by a mixed solvent of pressurized carbon dioxide and plating solution. Except that the forming material of the polymer molded product was changed, the polymer molded product was molded by injection molding in the same manner as in Example 1, and then plated in the mold used for molding to form the polymer molded product on the polymer molded product. A plating film was formed.

  In this example, after the electroless plating treatment, the residual plating solution was discharged from the mold with pressurized carbon dioxide, and then a clamping pressure of 100 tons was applied to the molded product simultaneously with the pressure reduction. This is to remove more of the mixed solution of pressurized carbon dioxide and plating solution from the inside of the polymer, to compress the swollen polymer molded product to improve the physical strength, and to correct the deformation of the polymer, etc. It is done for the purpose. This pressing step after plating may be performed in a mold or by batch processing. Moreover, you may carry out after the depressurization after plating reaction. By using such a method, the plating film forming method of the present invention can be applied to an amorphous thermoplastic resin that swells and deforms significantly.

  As in this example, the substance dissolved and extracted in the mixed solution of pressurized carbon dioxide, plating solution, water, and alcohol is blended with the resin material, so that the eluted substance is contained inside the polymer molded product. A dispersed polymer molded article is obtained, and when the mixed solution is brought into contact with such a polymer molded article, the mixed solution easily penetrates into the polymer molded article through the eluting substance. As such an elution substance, water-soluble materials, such as polyethylene glycol and surfactant, an amorphous thermoplastic resin component, various elastomers, etc. can be used.

  Further, as in this example, in the polymer molded product in which the eluted substance is dispersed inside, when the eluted material dispersed on the outermost surface is dissolved in the electroless plating solution, irregularities are formed on the surface of the polymer molded product, The physical anchor effect of the metal film on the surface of the polymer molded article is increased, and the adhesion of the metal film can be improved.

  In the polymer molded product of the present invention, in order to obtain the above effect, it is desirable that the eluting substance is dispersed in a depth region of at least 5 μm, more preferably 1 μm or less from the outermost surface of the polymer molded product. In this example, calcium carbonate fine particles were dispersed at a high concentration in a region from the outermost surface of the polymer molded product to a depth of about 0.5 μm. In addition, the impregnation depth of the eluted substance of the polymer molded product can be adjusted by the particle size of the eluted substance, the presence or absence of chemical modification to the eluted substance, and the like. Specifically, when the eluted substance is atomized or chemically modified to improve the compatibility with the resin, the eluted substance is easily dispersed on the surface of the molded product during injection molding.

  In this embodiment, the elution substance is eluted during the plating process. However, the elution process of the elution substance may be performed in a batch process before the plating process. In this case also, it is desirable to perform dissolution and extraction reaction of the eluted substance in a solution containing at least one of water, alcohol and pressurized carbon dioxide.

  In the plating film forming method of this embodiment, the electroless plating solution quickly penetrates into the resin while dissolving the calcium carbonate inside the resin and reacts with the catalyst core, so that the reaction of the plating thin film on the entire surface of the molded product. Time (plating processing time) has been greatly reduced. Specifically, when calcium carbonate was not dispersed inside the polymer molded article, the plating treatment time was 2 minutes, but in the method of this example, it was 1 minute. Moreover, the adhesion strength between the plating film and the polymer was improved by pressing the polymer molded product after the plating treatment as in the treatment method of this example. Specifically, when the press molding is not performed, the adhesion strength between the plating film and the polymer is 0.9 kgf / cm, but when the plating film is formed by the method of this example, the adhesion strength is 1. It became 3 kgf / cm.

  In the above Examples 1 to 4, the concentration of the metal fine particles (metal substance) on the plating film forming surface of the polymer molded product was adjusted according to the injection molding conditions, but the present invention is not limited to this. For example, as in Examples 5 to 9 described later, first, a polymer molded product in which metal fine particles are present on the outermost surface at a concentration at which electroless plating reaction occurs at atmospheric pressure, and then nitric acid, hydrochloric acid, The polymer molded product may be washed with an acid such as aqua regia to remove the outermost metal fine particles and adjust the concentration of the metal fine particles on the plating film forming surface. Another method is to prepare a polymer molded product in which metal fine particles are present on the outermost surface at a concentration at which electroless plating reaction occurs under atmospheric pressure, and then apply an electroless plating solution containing pressurized carbon dioxide. You may form the film | membrane which consists of material (For example, the same material as a polymer molded product) which lets it pass on the plating film formation surface of a polymer molded product.

  In Example 5, a method of forming an electroless plating film on the surface of a polymer member by batch processing will be described.

  In this embodiment, the mount of a camera lens module used in a mobile phone, a digital camera, or the like is used as the polymer member. A schematic cross-sectional view of the polymer member of this example is shown in FIG. As shown in FIG. 17, the camera lens module 701 includes a mount 702 having an inner hole 708, a lens 704, and a lens holder 703 that fixes the lens 704. 17A is a diagram when the mount 702 and the lens holder 703 are disassembled, and FIG. 17B is a diagram when the mount 702 and the lens holder 703 are combined. As shown in FIG. 17A, the lens holder 703 is provided with an inner hole 707, and the lens 704 is fixed to the inner hole 707. An imaging element such as a C-MOS sensor (not shown) is fixed to the lower part of the camera module 701.

  As shown in FIG. 17A, a screw groove 705 is formed on the outer wall of the lens holder 703, and the upper end portion of the inner wall of the inner hole 708 of the mount 702 is fitted with the screw groove 705 of the lens holder 703. A thread groove 706 is formed. By fitting the screw groove 705 of the lens holder 703 and the screw groove 706 of the mount 702, the mount 702 and the lens holder 703 are combined as shown in FIG.

  Note that in the camera lens module 701 used in a mobile phone, a digital camera, or the like, a subject image is formed on a sensor such as an image sensor such as a CCD or C-MOS by the lens 704, but due to electrical signal noise from the mobile phone body. As a method for suppressing an adverse effect on the module, it is desirable to shield the mount 702 adjacent to the image sensor with an electromagnetic wave. However, when a plating film is formed on the entire mount 702, if the inner wall surface of the mount 702 is a metallic gloss film, light is reflected inside the mount 702, which causes ghost flare. Therefore, in the final step of the plating film of this example, the surface of the mount 702 was subjected to black electroless plating.

  Further, in this example, reinforced polyphthalamide containing 65% glass fiber and mineral (Amodel AS-1566HS manufactured by Solvay Advanced Polymer) was used as a forming material of the polymer member 702 (mount).

[Plating equipment]
A schematic configuration diagram of the plating apparatus used in Example 5 is shown in FIG. As shown in FIG. 16, the plating apparatus 300 mainly includes a carbon dioxide cylinder 321, a filter 326, a high-pressure syringe pump 320, and a high-pressure container 301, and these components are connected by a pipe 327. In addition, as shown in FIG. 16, manual valves 322 to 324 for controlling the flow of pressurized carbon dioxide are provided at predetermined positions on the pipe 327 connecting the constituent elements.

  As shown in FIG. 16, the high-pressure container 301 includes a container main body 302 that stores an electroless plating solution 308 and a polymer member 702, and a lid 303. The lid 303 is provided with a polyimide seal 304 containing a known spring. The polyimide seal 304 seals high-pressure gas inside the high-pressure vessel 301. A holding member 305 that can suspend and hold a plurality of polymer members 702 in the electroless plating solution 308 is provided on the surface (lower surface) of the lid 303 on the plating solution 308 side. On the other hand, a magnetic stirrer 306 for stirring the electroless plating solution 308 is provided at the bottom of the container body 302. Further, the container body 302 has a temperature control flow path 307, and the temperature control water controlled in temperature by a temperature controller (not shown) is caused to flow into the temperature control flow path 307, whereby the high-pressure container 301. The temperature is adjusted. In this example, the temperature can be adjusted at any temperature from 30 ° C. to 145 ° C. Further, as shown in FIG. 16, a pressurized carbon dioxide inlet 325 was provided on the side wall of the container main body 302.

  In this example, SUS316L was used as a material for forming the high-pressure vessel 301. As a material for forming the high-pressure vessel 301, it is desirable to use a material that is not easily corroded, and SUS316, SUS316L, Inconel, Hastelloy, titanium, or the like can be used. Further, in this embodiment, in order to prevent a plating film from growing on the inner wall of the high-pressure vessel 301 when the inner wall surface of the high-pressure vessel 301 comes into contact with the electroless plating solution, the CVD (Chemical Vapor Deposition) A non-plated growth film made of DLC (diamond-like carbon) was formed by a chemical vapor deposition method. As the non-plated growth film, PTFE (polytetrafluoroethylene), PEEK (polyethyl ether ketone), or the like can also be used.

  In this example, nickel-phosphorus was used as the electroless plating solution 308. As the electroless plating solution, nickel-boron, palladium, copper, silver, cobalt, or the like may be used. Further, as the electroless plating solution 308, a solution that can be plated in a neutral or weakly alkaline to acidic bath is suitable, and in the case of nickel-phosphorus, it can be used in a pH range of 4 to 6, and is desirable. Depending on the conditions of the electroless plating solution 308 before introducing the pressurized carbon dioxide, the pH of the electroless plating solution 308 is lowered by allowing the pressurized carbon dioxide to penetrate (introduce) into the electroless plating solution. In addition, since the phosphorous concentration may increase and the plating film deposition rate may decrease, the pH of the electroless plating solution 308 may be increased in advance.

  In this example, Nicolon DK manufactured by Okuno Pharmaceutical Co., Ltd., which contains a nickel sulfate metal salt, a reducing agent, and a complexing agent, was used as a stock solution for the electroless plating solution 308. Further, alcohol was mixed with the electroless plating solution 308. The type of alcohol that can be used in this example is arbitrary, and methanol, ethanol, n-propanol, isopropanol, butanol, heptanol, ethylene glycol, and the like can be used. In this example, ethanol was used. More specifically, the ratio of each component in 1 l of the electroless plating solution is as follows: 150 ml of stock solution (Nicolon DK manufactured by Okuno Seiyaku Co., Ltd.) containing a metal salt of nickel sulfate and a reducing agent or complexing agent, 350 ml of water, And alcohol (ethanol) was made into 500 ml. That is, the ratio (volume ratio) of alcohol in the electroless plating solution 308 was 50%. In addition, since nickel sulfate was 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.

  According to the study by the present inventors, water is the main component of the electroless plating solution 308, but it is understood that carbon dioxide in a high pressure state and the electroless plating solution are easily mixed stably by mixing alcohol. It was. This is considered due to the fact that alcohol and supercritical carbon dioxide are easily compatible. Therefore, when alcohol is mixed with the electroless plating solution as in this embodiment, it is not necessary to add a surfactant to the electroless plating solution or to stir the electroless plating solution. Furthermore, in order to allow the plating solution to penetrate into the polymer member together with the pressurized carbon dioxide to grow the plating reaction inside the polymer member, the surface tension is lower when alcohol is added to the plating solution than with water alone. Is more preferable. However, in the present invention, a surfactant may be added or the electroless plating solution may be stirred in order to further improve the compatibility (affinity) between the pressurized carbon dioxide and the electroless plating solution. In this example, as described later, a surfactant was added to the electroless plating solution, and the electroless plating solution was also stirred.

  In this example, octaethylene glycol monododecyl ether as a surfactant was further added at 3 wt% with respect to the electroless plating solution 308.

  In the syringe pump 320 of the plating apparatus 300 used in this example, the pressure inside the high-pressure vessel 301 and the density of the pressurized carbon dioxide were changed by controlling the pressure constant with the manual valves 322 and 323 opened. Even in such a case, it is possible to absorb pressure fluctuations and thereby to stably hold the pressure inside the high-pressure vessel 301.

[Method of forming plating film]
First, a polymer member 702 (mount) in which metal fine particles penetrated into the surface was prepared (prepared) as follows. A polymer member 702 having a predetermined shape shown in FIG. 17 was formed by injection molding. Next, the molded polymer member 702 and the metal complex were mounted in a high-pressure container (not shown) of a surface modification device (not shown). At this time, the polymer member 702 was held in the high-pressure vessel so that the entire surface of the polymer member 702 was in contact with supercritical carbon dioxide (hereinafter referred to as supercritical carbon dioxide) to be introduced into the high-pressure vessel later. In this example, hexafluoroacetylacetonato palladium (II) was used as the metal complex.

  Next, 15 MPa of supercritical carbon dioxide was introduced into the high-pressure vessel. At this time, the metal complex charged in the high-pressure vessel is dissolved in supercritical carbon dioxide and penetrates into the entire surface of the polymer member 702 together with the supercritical carbon dioxide. Next, by holding the pressure in the high-pressure vessel at 120 ° C. for 30 minutes, a part of the metal complex that has permeated the entire surface of the polymer member 702 is reduced. In this example, the polymer member 702 in which the metal fine particles penetrated into the inside of the surface was produced in this way (step S51 in FIG. 21). This state is shown in FIG. 18, where the black circles 709 in FIG. 18 are the metal fine particles penetrating the inside of the surface of the polymer member 702. In the polymer member 702 in which the metal fine particles produced as described above have permeated the inside of the surface, the metal fine particles are dispersed on the outermost surface of the polymer member 702 at a concentration at which a plating reaction occurs at atmospheric pressure.

  Next, after attaching the polymer member 702 manufactured as described above to the holding member 305 of the lid 305 of the high-pressure vessel 301 shown in FIG. 16, the polymer member 702 is inserted into the container body 302 and the lid 303 is inserted. Was closed and the high-pressure vessel 301 was sealed. The container body 302 is filled with 70% of the inner volume of the container body 302 in advance, and the container body 302 is sealed with a lid 303, whereby an electroless plating solution containing a surfactant and alcohol is sealed. A plurality of polymer members 702 are suspended in 308 (state in FIG. 16, step S52 in FIG. 21). However, at this time, the temperature of the high-pressure vessel 301 and the electroless plating solution 308 is 50 or lower than the plating reaction temperature (70 ° C. to 85 ° C.) due to the temperature-controlled water flowing through the temperature adjustment flow path 307 of the high-pressure vessel 301. Adjusted to ° C. Therefore, at this point, the polymer member 702 is in contact with the electroless plating solution at a temperature lower than the plating reaction temperature (the temperature at which the plating reaction does not occur), and the plating film does not grow on the surface of the polymer member 702.

  Next, pressurized carbon dioxide was introduced into the high-pressure vessel 301 that was temperature-controlled at a low temperature at which no plating reaction occurred as follows. In this example, supercritical carbon dioxide was used as pressurized carbon dioxide. First, the liquid carbon dioxide taken out from the liquid carbon dioxide cylinder 321 was sucked up by the high-pressure syringe pump 320 through the filter 326, and then the pressure was increased to 15 MPa in the pump (supercritical carbon dioxide was generated). Next, the manual valves 322 and 323 were opened, 15 MPa of supercritical carbon dioxide was introduced into the high-pressure vessel 301 through the inlet 325, and contacted with the polymer member 702 (step S53 in FIG. 21). At this time, the surface of the polymer member 702 is swollen by the introduced supercritical carbon dioxide, and the surface tension of the plating solution mixed with the supercritical carbon dioxide is low. Therefore, the electroless plating solution 308 is supercritical. It penetrates inside the polymer member together with carbon dioxide. As a result, the electroless plating solution 308 reaches the fine metal particles present inside the polymer member 702. In this example, since the electroless plating solution 308 contains alcohol, the surface tension of the electroless plating solution 308 is further reduced, so that the electroless plating solution 308 easily penetrates into the polymer member 702.

  In this example, after the supercritical carbon dioxide was introduced, the electroless plating solution 308 was agitated by rotating the magical stirrer 306 at a high speed. As described above, in this example, since the electroless plating solution contains alcohol, the phase between the supercritical carbon dioxide and the plating solution can be obtained without diffusing the electroless plating solution 308 by using the magnetic stirrer 306. Although sufficient solubility can be secured, in this example, the electroless plating solution 308 was agitated with a magretic stirrer 306 in order to increase the compatibility between the supercritical carbon dioxide and the plating solution.

  Next, the temperature of the high-pressure vessel 301 was raised to 85 ° C., and a plating reaction was caused in the high-pressure vessel 301 (electroless plating was performed) to form a plating film on the surface of the polymer member 702 (in FIG. 21). Step S54). At this time, in the plating film forming method of this example, since the electroless plating solution penetrates to the metal fine particles existing inside the polymer member 702 as described above, not only the surface of the polymer member 702, A plating film grows using the metal fine particles existing inside as catalyst nuclei. That is, in the plating film forming method of this example, the plating film grows also in the free volume inside the polymer member 702, and the plating film is formed on the polymer member 702 in a state of being bitten into the polymer member 702. The

  After the completion of plating, the magnetic stirrer 306 was stopped and allowed to stand for a while to separate the carbon dioxide and the plating solution into two phases in the high-pressure vessel 301. Thereafter, the manual valve 322 was closed, the manual valve 324 was opened, and the carbon dioxide in the high-pressure vessel 301 was exhausted. Next, the high-pressure vessel 301 was opened, and the polymer member 702 was taken out from the high-pressure vessel 301. When the taken out polymer member 702 was visually confirmed, metallic luster was observed on the entire surface of the polymer member 702.

  Next, the polymer member 702 was annealed at 150 ° C. for 1 hour in order to degas the carbon dioxide and the electroless plating solution from the inside of the polymer member 702 taken out from the high-pressure vessel 301. Next, the oxidized plating film surface was activated with hydrochloric acid. After that, electroless plating is performed at atmospheric pressure using a conventional electroless nickel-phosphorous solution in the atmosphere, a 500 nm thick plating film is laminated, and an electroless copper plating is further formed thereon with a thickness of 1 μm. And an electromagnetic wave shielding film was applied. Next, black electroless plating was performed, and a black electroless nickel-phosphorous plating film was laminated on the electroless copper plating film. The blackening was performed by plating using a dedicated electroless nickel-phosphorous plating solution and then roughening the surface by etching. This is because the inner wall of the polymer member 702 (mount) is blackened to suppress ghost flare due to light reflection. In this example, as described above, a polymer member was obtained in which the entire surface of the polymer member 702 as shown in FIG. 19 was covered with a metal film (reference numeral 710 in FIG. 19).

[Evaluation of plating film]
For the polymer member 702 manufactured as described above, a high-temperature and high-humidity test (conditions: temperature 80 ° C., humidity 90% Rh, standing time 500 hours) and heat cycle test (between temperatures between 80 ° C. and 150 ° C.) After performing a peel test after 15 cycles, no film peeling occurred. Further, when the above process of this example was repeated, no growth of plating film or corrosion of the inner wall of the container was observed in the high pressure container 301.

  Moreover, the cross section of the surface vicinity of the polymer member 702 produced in this example was observed with SEM (scanning electron microscope). The results are shown in FIG. A region 702a in FIG. 20 is a region of the polymer member 702 in which no plating film is formed, and a region 702b is a layer in which a metal film is grown inside the polymer member 702. A region 702c in FIG. 20 is a region of a metal film formed when electroless plating is performed at normal pressure using a conventional electroless nickel-phosphorus solution in the atmosphere. A region 702d is a region of the electroless copper plating film. Therefore, the vicinity of the boundary between the region 702 b and the region 702 c is the outermost surface of the polymer member 702. As is apparent from the observation image of FIG. 20, it was confirmed that a layer in which a metal film was grown was formed inside the polymer member 702 (region 702b in FIG. 20).

  In this example, when a metal component present in the polymer member 702 was subjected to component analysis using an XRD (X-ray diffractometer), Ni, P and Pd were detected. From this result, it was confirmed that Pd derived from a metal complex that penetrated into the polymer member 702 worked as a catalyst, and a Ni-P plating film was grown inside the polymer.

  In Example 6, as in Example 5, a method for forming an electroless plating film on the surface of a polymer member by batch processing will be described. In this example, a high pressure vessel having a structure different from that of Example 5 was used as the high pressure vessel in the plating apparatus. The electroless plating solution used in this example was the same as in Example 5. In this example, similarly to Example 5, a metal film was formed on the surface of the camera lens module mount (mount 702 having the structure shown in FIG. 17). Moreover, supercritical carbon dioxide was used as the pressurized carbon dioxide introduced into the electroless plating solution.

[Plating equipment]
A schematic configuration diagram of the plating apparatus used in Example 6 is shown in FIG. As shown in FIG. 22, the plating apparatus 400 mainly includes a carbon dioxide cylinder 421, a filter 426, a high-pressure syringe pump 420, and a high-pressure container 401, and these components are connected by a pipe 427. Yes. Further, as shown in FIG. 22, manual valves 422 to 424 for controlling the flow of supercritical carbon dioxide are provided at predetermined positions on a pipe 427 that connects the components.

  As shown in FIG. 22, the high-pressure container 401 includes a container main body 402, a lid 403, and an internal container 409 accommodated in the container main body 402. The lid 403 has the same structure as that of the fifth embodiment except that the lid 403 does not include a holding member that holds the polymer member 702 as in the fifth embodiment. The container body 402 of this example has the same structure as that of Example 5 except that the non-plated growth film is not provided on the inner wall surface. In the plating apparatus 400 of this example, an inner container 409 made of PTFE (polytetrafluoroethylene) that can be accommodated in the metal container body 402 is used, and the polymer member 702 is electrolessly plated in the inner container 409. Was given.

  As shown in FIG. 22, the inner container 409 includes a container main body 409 a in which the electroless plating solution 408 and the polymer member 702 are accommodated, and a lid 409 b. A holding member 405 capable of suspending and holding a plurality of polymer members 702 in the electroless plating solution 408 is provided on the surface (lower surface) of the lid portion 409b on the electroless plating solution 408 side. The holding member 405 has the same structure as the holding member of the fifth embodiment. On the other hand, a magnetic stirrer 406 for stirring the electroless plating solution 408 is provided at the bottom of the container body 409a. In addition, a screw groove is formed on the outer wall near the upper end of the container main body 409a, and a screw groove is formed on the inner wall of the lid 409b to be mated with a screw groove provided on the outer wall of the upper end of the container main body 409a. Yes. Then, the inner container 409 is closed by fitting the screw groove of the container main body 409a and the screw groove of the lid 409b.

[Method of forming plating film]
First, in this example, in the same manner as in Example 5, a polymer member 702 (mount 702 having the shape shown in FIG. 18) in which metal fine particles penetrated into the surface was prepared (prepared). In this example, hexafluoroacetylacetonato palladium (II) was used as the metal complex.

  Next, after the molded polymer member 702 was attached to the holding member 405 of the lid portion 409b of the inner container 409 shown in FIG. 22, the polymer member 702 was inserted into the container main body portion 409a and the lid portion 409b was closed. . At this time, as shown in FIG. 22, a plurality of polymer members 702 are suspended in an electroless plating solution 408 containing a surfactant and alcohol. And this state was hold | maintained at normal temperature. Therefore, at this time, since the temperature of the electroless plating solution 408 is equal to or lower than the plating reaction temperature (70 ° C. to 85 ° C.), the plating film does not grow on the surface of the polymer member 702.

  Next, the inner vessel 409 is inserted into the high-pressure vessel 401 that has been previously adjusted to 90 ° C., the lid 403 is closed, and immediately, supercritical carbon dioxide is introduced through the inlet 425 in the same manner as in Example 5. And introduced into the high-pressure vessel 401. Thereafter, the electroless plating solution 408 was stirred with a magnetic stirrer 406. At this time, the container body 409a and the lid 409b of the inner container 409 are fitted with screws as described above, but even in that state, supercritical carbon dioxide has low viscosity and high diffusibility. The inner container 409 is sufficiently introduced into the inner container 409 through a slight gap in the portion engaged with the screw. At this time, since the resin having low thermal conductivity is used for the inner container 409, the temperature in the inner container 409 does not rise rapidly, so that the temperature is lower than the temperature at which the plating reaction occurs. In addition, the plating film does not grow on the surface of the polymer member 702. Therefore, when the internal container 409 is inserted into the high-pressure container 401 and supercritical carbon dioxide is immediately introduced, the surface of the polymer member 702 swells and the supercritical carbon dioxide is mixed as in the fifth embodiment. Since the plating solution has a low surface tension, the electroless plating solution penetrates into the polymer member 702 together with the supercritical carbon dioxide, and the electroless plating solution reaches the metal fine particles existing inside the polymer member 702.

  Thereafter, with the passage of time, the temperature in the inner container 409 rises, and finally the temperature of the electroless plating solution 408 etc. rises to the plating reaction temperature. At that time, a plating reaction occurs in the inner container 409 and a plating film grows on the surface of the polymer member 702. At this time, in the plating film forming method of this example, since the electroless plating solution penetrates to the metal fine particles existing inside the polymer member 702 as described above, not only the surface of the polymer member 702, A plating film grows using the metal fine particles existing inside as catalyst nuclei. In other words, in the plating film forming method of this example, the plating film is formed on the polymer member in a state of being bitten into the polymer member 702.

  Next, after the plating process described above (about 30 minutes after the insertion of the inner container 409), supercritical carbon dioxide was exhausted from the high-pressure container 401, and the inner container 409 was kept at 90 ° C. as it was. By this process, a plating film was further grown at normal pressure on the plating film grown from the inside of the polymer member 702. Thereafter, the inner container 409 was taken out from the high-pressure container 401, and then the polymer member 702 was taken out from the inner container 409. Subsequently, the polymer member 702 taken out from the inner container 409 was subjected to electroless copper plating and black electroless nickel-phosphorous plating in the same manner as in Example 5. In this example, as described above, a polymer member 702 having the entire surface as shown in FIG. 19 covered with a metal film (reference numeral 710 in FIG. 19) was obtained.

[Evaluation of plating film]
When the environmental test (high temperature and humidity test, heat cycle test) and adhesion evaluation (peel test) were performed on the polymer member 702 produced as described above in the same manner as in Example 5, Example 5 and Similarly, it was found that a plating film with high adhesion was formed on the polymer member 702.

  Further, no plating film was confirmed inside the high-pressure vessel 401 of this example. Therefore, as in this embodiment, when a resin-made inner container is used, plating does not grow on the inner wall of the high-pressure vessel 401 without coating the inside of the high-pressure vessel 401. It can be carried out. Further, since the corrosion of the surface of the high-pressure vessel 401 can be suppressed, the plating apparatus is suitable as a plating film forming method using supercritical carbon dioxide.

  In Example 7, the same plating apparatus as in Example 6 was used except that the surfactant was not added to the electroless plating solution and that the electroless plating solution was not stirred with a magnetic stirrer. Then, the electroless plating treatment was performed on the polymer member by the same method.

  Further, for the polymer member produced in this example, environmental tests (high temperature and humidity test, heat cycle test) and adhesion evaluation (peel test) were conducted in the same manner as in Example 6. Similarly, it was found that a highly adhesive plating film was formed on the polymer member. That is, according to the method for forming a plating film of the present invention, there is no need to improve the affinity (compatibility) between the supercritical carbon dioxide and the electroless plating solution by using a surfactant or a magnetic stirrer. It has been found that a plating film having good adhesion can be formed on a polymer by adding only alcohol to the electrolytic plating solution.

  In Example 8, the polymer member was coated with the same method as in Example 5 except that the inner wall of the high-pressure vessel of the plating apparatus was not coated with a non-plated growth film. Electrolytic plating was performed.

  Further, for the polymer member produced in this example, environmental tests (high temperature and humidity test, heat cycle test) and adhesion evaluation (peel test) were conducted in the same manner as in Example 5. Similarly, it was found that a plating film with good adhesion was formed on the polymer member. However, in this example, since the non-plated growth film was not formed on the inner wall of the high-pressure vessel of the plating apparatus, the growth and corrosion of the plating film was confirmed on the inner wall of the high-pressure vessel.

[Comparative Example 1]
In Comparative Example 1, alcohol was not mixed in the electroless plating solution, the pressure of supercritical carbon dioxide was increased to 20 MPa in the electroless plating solution, and stirring was not performed in the inner container of the plating apparatus. Except for the above, the electroless plating treatment of the polymer member was performed in the same manner as in Example 6 using the same plating apparatus as in Example 6.

  Also, for the polymer member produced in this example, environmental tests (high temperature and humidity test, heat cycle test) and adhesion evaluation (peel test) were conducted in the same manner as in Example 5. The polymer member peeled off the electroless plating film.

Table 1 summarizes the form of the high-pressure vessel, the conditions of the electroless plating solution, and the evaluation results in Examples 5 to 8 and Comparative Example 1. In addition, the evaluation criteria of the adhesion of the plating film and the corrosivity of the high-pressure inner wall in Table 1 are as follows.
Plating film adhesion:
◎ When there is no problem in the peel test after the environmental test (high temperature and high humidity, heat cycle test) (when there is no peeling of the plating film or film swelling)
○ When there is no problem in the peel test before the environmental test × When peeled off during the peel test before the environmental test Corrosion of the inner wall of the container and growth of the plating film:
○ When there is no rust or plating film growth on the container inner wall × When rust or plating film growth occurs on the container inner wall

  In Example 9, a method of performing electroless plating in the same injection molding machine after injection molding of a polymer molded product using the same injection molding machine as in Example 1 will be described. However, in this example, the forming process and the electroless plating process were performed by a method different from that of Example 1. In this example, as in Example 1, an automobile headlight reflector was produced as a polymer molded product.

[Molding method of polymer molded product]
A method for forming a polymer molded article in which metal fine particles are infiltrated into the surface in this embodiment will be described with reference to FIGS. In this example, similarly to Example 1, pressurized carbon dioxide in which metal fine particles were dissolved was introduced into the tip (flow front part) of the molten resin plasticized and measured in the plasticizing cylinder 52.

  First, the metal complex was dissolved in ethanol in the dissolution tank 35, and the ethanol in which the metal complex was dissolved was increased to 15 MPa in the syringe pump 34. On the other hand, the liquid carbon dioxide cylinder 21 was supplied to the syringe pump 20 via the filter 57, and the liquid carbon dioxide pressure was increased to 15 MPa in the syringe pump 20. The pressurized carbon dioxide and ethanol in which the metal complex was dissolved were mixed in the pipe 80 (a pressurized mixed fluid was generated). When the pressurized mixed fluid was supplied to the plasticizing and melting apparatus 110, the supply pressure of the pressurized mixed fluid was controlled by the back pressure valve 48 so that the display of the pressure gauge 49 became 15 MPa. Further, the feeding of the pressurized mixed fluid of the ethanol solution and the pressurized carbon dioxide from both syringe pumps 20 and 34 was performed by switching the control of each syringe pump 20 and 34 from the pressure control to the flow rate control. Furthermore, when supplying the pressurized mixed fluid to the plasticizing and melting apparatus 110, the pressurized mixed fluid was supplied to the plasticizing and melting apparatus 110 while controlling the temperature in the pipe 80 to 50 ° C. by a heater (not shown).

  Next, a procedure for introducing the pressurized mixed fluid into the plasticizing and melting apparatus 110 will be described with reference to FIGS. First, while supplying resin pellets from the hopper 50, the screw 51 in the plasticizing cylinder 52 was rotated to measure plasticization of the resin. FIG. 2A shows a state in the vicinity of the introduction valve 65 when the plasticizing measurement is completed. At this time, as shown in FIG. 2A, the introduction pin 70 of the introduction valve 65 moves backward (moves to the left side in FIG. 2A), so that the pressurized mixed fluid 67 is fed to the molten resin 66. It is blocked from being introduced.

  Next, the screw 51 is sucked back (retracted) to reduce the internal pressure of the molten resin 66, and at the same time, both syringe pumps 20, 34 are switched from pressure control to flow rate control, and ethanol and carbon dioxide in which the metal complex is dissolved. The pressurized mixed fluid 67 was introduced into the molten resin 66 at the flow front portion in the plasticizing cylinder 52 via the introduction valve 65 (FIG. 2B). Status). A region 68 in FIG. 2B is a portion of the molten resin into which the pressurized mixed fluid 67 has permeated. The pressurized mixed fluid 67 was introduced while monitoring the resin pressure and the pressure of the pressurized mixed fluid 67 with the pressure sensors 40 and 47, respectively.

  Subsequently, both syringe pumps 20 and 34 were stopped, and liquid feeding of the pressurized mixed fluid 67 was stopped. At the same time, the screw 51 is advanced to increase the resin pressure again, and the introduction pin 70 is retracted (moved leftward in FIG. 2B). Thus, the introduction of the pressurized mixed fluid 67 was stopped, and the pressurized mixed fluid 67 and the molten resin 66 were made compatible.

  Subsequently, after closing both the syringe pumps 20 and 34 in an automatic valve (not shown) in the pipe 80, the flow rate of the ethanol solution in which the pressurized carbon dioxide and the metal complex supplied to the plasticizing and melting apparatus 110 are dissolved is the syringe pump 20. , 34 was replenished. After that, the pressure control was switched to 15 MPa, and the system was kept waiting until the next shot was fed.

  Next, after the pressurized mixed fluid 67 is introduced into the molten resin 66 in the flow front part in the plasticizing cylinder 52, the mold is clamped by a hydraulic mold clamping mechanism (not shown) of the mold clamping device 111, and a temperature control circuit (not shown). The molten resin was injected and filled into the cavity 104 defined in the mold controlled in temperature by the illustration. At this time, the injection speed until injection filling was set to 200 m / s.

  Next, the molded product was cooled and solidified (state shown in FIG. 3). When the molten resin is injection-molded into the mold, the molten resin 68 in the flow front portion that is injected first forms the skin of the injection-molded product by the fountain effect (fountain flow). That is, in this example, metal fine particles derived from the metal complex are dispersed in the vicinity of the flow front portion, and therefore, as shown in FIG. 3, the polymer 507 (inside the surface) of the polymer molded product 507 has a polymer impregnated with metal fine particles. A molded product 507 is obtained (step S91 in FIG. 23). In this example, in this way, the metal fine particles were dispersed in the skin layer 505 as the epidermis, and a polymer molded product 507 ′ having almost no metal fine particles in the core layer 506 as the endothelium was obtained.

  In the molding process of the present embodiment, as described above, the pressure reduction process is not performed after the metal complex is sufficiently infiltrated into the resin in the flow front portion in the plasticizing cylinder 52 as in the first embodiment. And the resin of the flow front part was injected at a higher speed than Example 1. By this operation, when the skin layer is formed by injection filling described later, the metal fine particles and carbon dioxide gas easily float on the surface of the skin layer (the outermost surface of the molded product), and the plating reaction occurs at atmospheric pressure. Metal fine particles are dispersed on the surface of the skin layer (the outermost surface of the molded product) at a concentration (see FIG. 24).

[Method of forming plating film]
The polymer molded product 507 in which metal fine particles were dispersed inside the surface produced as described above was subjected to electroless plating in a mold as follows. During the electroless plating process, the temperature inside the mold was adjusted to 80 ° C.

  First, as shown in FIG. 4, the movable platen 56 and the movable mold 54 are moved backward by retreating the hydraulic mold clamping mechanism (not shown) of the mold clamping device 111 (downward in FIG. 4), so that the fixed mold is fixed. A gap 508 (cavity 508) was provided between the mold 53 and the polymer molded product 507.

  Next, the carbon dioxide supplied from the carbon dioxide cylinder 21 of the electroless plating apparatus unit 101 was pressurized by the pump 19 and stored in the buffer tank 36. Next, the automatic valve 43 is opened, and the pressurized carbon dioxide stored in the buffer tank 36 is introduced into the cavity 508 through the plating solution introduction path 61 to bring the pressurized carbon dioxide into contact with the surface of the polymer molded product 507. (Step S92 in FIG. 23). At this time, since the cavity 508 is sealed by fitting the spring-incorporated seal 17 provided on the outer diameter portion of the fixed mold 53 and the movable mold 54, the introduced pressurized carbon dioxide is outside the mold. Never leak out. At this time, the pressure of the pressurized carbon dioxide in the cavity 508 was set to 15 MPa. Since the surface of the polymer molded product 507 swells when the pressurized carbon dioxide is brought into contact with the surface of the polymer molded product 507 in this way, the mixed fluid of the pressurized carbon dioxide and the electroless plating solution to be introduced next The effect that the penetration into the inside of the polymer molded product 507 is performed more smoothly is obtained.

  Next, an electroless plating solution containing pressurized carbon dioxide was introduced into the cavity 508 and brought into contact with the polymer molded product 507 as follows. First, an alcohol and surfactant-mixed electroless plating solution supplied from the plating tank 11 of the electroless plating apparatus unit 101 and a 15 MPa pressurized carbon dioxide supplied from the buffer tank 36 in advance are used. Mixed inside. The electroless plating solution of this example was prepared so that the ratio of each component contained therein was the same as in Example 5. At this time, the pressurized carbon dioxide and the electroless plating solution were dissolved in the high-pressure vessel 10 by driving the stirrer 16 and rotating the magnetic stirrer 6 at high speed. Subsequently, the automatic valve 43 was closed and the automatic valves 44 and 45 were opened.

  Next, the circulation pump 90 is operated, and an electroless plating solution containing pressurized carbon dioxide is circulated through a circulation flow path including the high-pressure vessel 10, the pipe 15, and the cavity 508, so that the surface of the polymer molded product 507 is electrolessly plated. The liquid was contacted to form a plating film (nickel phosphorus film) (step S93 in FIG. 23). At this time, since the surface of the polymer molded product 507 is swollen, the electroless plating solution permeates into the polymer molded product 507 from the surface of the polymer molded product 507 and the metal fine particles dispersed inside the polymer molded product 507 are dispersed. A plating film grows as a catalyst nucleus. That is, since the plating film formed on the polymer molded product 507 grows in a state of being bitten into the polymer molded product 507, a plating film having excellent adhesion is formed. When the electroless plating solution containing pressurized carbon dioxide was circulated, the pressures in the cavities 508 and the circulation line 15 were the same by the pressure sensors 58 and 59. Further, replenishment of the electroless plating solution was performed at any time by increasing the pressure of the plating solution supplied from the plating tank 11 with the syringe pump 33 and feeding it simultaneously with the opening of the automatic valve 46.

  Next, after forming a plating film on the polymer molded product 507 as described above, the electroless plating solution containing pressurized carbon dioxide is circulated through the collection vessel 63 from the circulation path of the electroless plating solution containing pressurized carbon dioxide. Exhausted from the recovery tank 12. Specifically, the automatic valves 44 and 45 were closed, and then the automatic valve 38 was opened, whereby the electroless plating solution containing pressurized carbon dioxide was discharged into the collection container 63. In the recovery container 63, the electroless plating solution containing the recovered pressurized carbon dioxide is separated into an aqueous solution (plating solution) and a high-pressure gas (carbon dioxide) by the principle of centrifugation. The plating solution can be recovered in the recovery tank 12 and reused. The gasified carbon dioxide is discharged from the upper part of the recovery container 63 and recovered in an exhaust duct (not shown).

  Next, the automatic valve 43 is opened for a certain period of time, and pressurized carbon dioxide is introduced into the gap 508 (cavity 508) between the fixed mold 53 and the polymer molded product 507, and the plating solution residue remaining in the cavity 508 is removed. It was discharged out of the mold together with the pressurized carbon dioxide. Next, when the internal pressure of the cavity 508 became zero as monitored by the pressure sensor 59, the mold was opened and the polymer molded product 507 was taken out.

  Next, the extracted polymer molded product 507 was subjected to normal substitutional gold plating, and a gold plating film was laminated on the surface of the polymer molded product 507. In this example, a polymer molded product 507 having a plating film formed on the surface was obtained as described above.

  FIG. 24 shows a schematic cross-sectional view of a part of the polymer molded product 507 produced in this example. It was confirmed that metal fine particles 600 (black circles in FIG. 24) are dispersed in the skin layer 505 of the polymer molded product 507 produced in this example. Further, a nickel-phosphorus metal film 509 grown in a mold is formed on one side of the polymer molded article 507, and the nickel-phosphorus metal film 509 grew from the inside of the polymer molded article 507 (metal The permeation layer of the membrane 509 was formed). Also, a gold highly reflective film 510 was formed on the nickel-phosphorus metal film 509.

  In addition, the adhesion evaluation of the metal film was also performed on the polymer molded product 507 produced in this example by the same high temperature and high humidity environment test as in Example 5. A high temperature test was also conducted under conditions of a temperature of 150 ° C. and a notification time of 500 hours. As a result, the same results as in Example 5 were obtained, and no decrease in the adhesion of the metal film was observed. Furthermore, when the surface roughness Ra of the polymer molded product 507 produced in this example was measured, Ra = 100 nm, which is equivalent to the surface roughness of the mold. That is, according to the plating film forming method of this example, the plating process can be performed simultaneously with the injection molding, and not only can the process be simplified, but also a metal film having high adhesion and smoothness can be made heat resistant. It was found that it can be formed into a high resin material.

  In the electroless plating treatment of Example 9 above, first, only the pressurized carbon dioxide was brought into contact with the polymer molded article to swell the surface of the polymer molded article, and then the electroless plating solution was brought into contact with the polymer molded article. However, the present invention is not limited to this. For example, a first electroless plating solution containing a pressurized carbon dioxide in a polymer molded article and having a plating solution concentration that does not cause a plating reaction is brought into contact with the polymer molded article. A plating film may be formed by bringing a second electroless plating solution having a concentration of the plating solution to occur into contact with the polymer molded product. Here, the plating solution concentration refers to the concentration of a reducing agent such as sodium hypophosphite that is a factor that determines the plating reaction in the plating solution. That is, the above method will be described more specifically. An electroless plating solution (first electroless plating solution) and a pressurized carbon dioxide that are sufficiently small to prevent a plating reaction from occurring and pressurized carbon dioxide are brought into contact with a polymer molded product. Then, the plating solution is infiltrated into the polymer, and then the first electroless plating solution is electrolessly plated (a second electroless plating solution) containing a reducing agent to such an extent that a plating reaction occurs sufficiently. May be substituted. Alternatively, a second electroless plating solution can be obtained by adding a solvent containing water or alcohol containing a reducing agent as a main component and pressurized carbon dioxide to the first electroless plating solution having a small reducing agent. It may be formed.

  In Examples 1 to 9 described above, the example in which the crystal material is used as the forming material of the polymer member (polymer molded product) has been described. However, the present invention is not limited to this, and as the forming material of the polymer member (polymer molded product). The same effect can be obtained even when an amorphous material is used.

  In the plating film forming method of the present invention, a plating film grown from the inside of the polymer can be formed without roughening the surface of the polymer, so that plating with excellent adhesion to various types of polymers is possible. It is the most suitable method for forming a film.

  Further, in the method for forming a plating film of the present invention, when an electroless plating process is performed in an injection molding machine, a smooth metal film with high adhesion can be formed on a resin material with high heat resistance. It is suitable as a method for producing a reflector for an automotive headlight that requires heat resistance.

FIG. 1 is a schematic configuration diagram of a manufacturing apparatus used in the first embodiment. FIG. 2 is a view showing a state in which pressurized carbon dioxide in which a metal complex is dissolved in a molten resin in a plasticizing cylinder is introduced, and FIG. FIG. 2 (b) is a diagram showing a state when pressurized carbon dioxide is introduced. FIG. 3 is a view showing a state when the injection molding of the polymer molded product is completed in the method for producing a polymer molded product of Example 1. FIG. FIG. 4 is a diagram showing a state where the polymer molded product is subjected to an electroless plating process in the method for producing a polymer molded product of Example 1. FIG. 5 is a flowchart for explaining the procedure of the plating film forming method according to the first embodiment. 6 is a diagram schematically showing a cross-sectional structure of a polymer molded product after molding in Example 1. FIG. FIG. 7 is a diagram schematically showing a cross-sectional structure of the polymer molded product produced in Example 1. FIG. 8 is a schematic configuration diagram of the molding apparatus used in the second embodiment. FIG. 9 is a diagram for explaining the procedure of the method for producing a polymer substrate in Example 2. FIG. 10 is a view for explaining the procedure of the method for producing a polymer substrate in Example 2. FIG. 11 is a diagram for explaining the procedure of the method for producing a polymer substrate in Example 2. FIG. 12 is a diagram for explaining the procedure of the method for producing a polymer substrate in Example 2. FIG. 13 is a diagram for explaining the procedure of the method for producing a polymer substrate in Example 2. FIG. 14 is a diagram for explaining the procedure of the method for producing a polymer substrate in Example 2. FIG. 15 is a flowchart for explaining the procedure of the method for producing a polymer substrate in Example 2. FIG. 16 is a schematic configuration diagram of a plating apparatus used in the fifth embodiment. 17 is a schematic cross-sectional view of the polymer member produced in Example 5, FIG. 17 (a) is a view when the mount and the lens holder are disassembled, and FIG. 17 (b) is a combination of the mount and the lens holder. FIG. FIG. 18 is a schematic cross-sectional view of a polymer member after surface modification of the polymer member in the plating film forming method of Example 5. FIG. 19 is a schematic cross-sectional view of the polymer member after the plating film is formed on the surface of the polymer member in the plating film forming method of Example 5. FIG. 20 is an SEM image near the surface of the polymer member produced in Example 5. FIG. 21 is a flowchart for explaining the procedure of the plating film forming method according to the fifth embodiment. FIG. 22 is a schematic configuration diagram of the plating apparatus used in Example 6. FIG. 23 is a flowchart for explaining the procedure of the plating film forming method according to the ninth embodiment. FIG. 24 is a diagram schematically showing a cross-sectional structure of a polymer molded product produced in Example 9.

Explanation of symbols

500 Manufacturing apparatus 501 Electroless plating apparatus section 502 Surface modification apparatus section 503 Injection molding apparatus section 504 Cavity 505 Skin layer (skin)
506 Core layer 507 Polymer molded product 509 Electroless nickel-phosphorus film 550 Metal fine particles

Claims (5)

A method of forming a plating film on a polymer member,
Preparing a polymer member impregnated with a metal substance that becomes a plating catalyst core inside the surface;
Nickel phosphorus plating solution containing pressurized carbon dioxide and alcohol into contact with the polymer member, the above polymer member, see containing and forming a plated film grown from the inside of the polymer member,
The method for forming a plating film, wherein a volume ratio of the alcohol in the nickel phosphorus plating solution is 30 to 60% . Preparing the polymer member using a molding machine and preparing the polymer member introduces pressurized carbon dioxide in which the metal substance is dissolved into the molten resin of the polymer member in the molding machine, and the metal The method for forming a plating film according to claim 1, comprising molding a molten resin into which a substance has been introduced . Forming a plating film on the polymer member includes contacting the polymer substrate with pressurized carbon dioxide to swell the vicinity of the surface of the polymer member, and applying pressure in a state where the surface of the polymer member is swollen. The method for forming a plating film according to claim 1 , further comprising contacting a nickel phosphorus plating solution containing carbon dioxide with the polymer member .   An electroless plating solution for use in the method for forming a plating film of a polymer member according to any one of claims 1 to 3,
  An electroless plating solution comprising an alcohol-containing nickel phosphorus plating solution, wherein a volume ratio of the alcohol in the nickel phosphorus plating solution is 30 to 60%.   The electroless plating solution according to claim 4, further comprising pressurized carbon dioxide.

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