JP2011001576A - Plating-pretreatment method for polymeric base material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a plating film with excellent adhesiveness at low cost when executing the electroless plating treatment on a polymeric base material.SOLUTION: A plating-pretreatment method for a polymeric base material includes: an impregnating step of impregnating an organometallic complex in a polymeric base material 21 by bringing the polymeric base material 21 and a pressurized fluid containing an organometallic complex into contact with each other at the temperature below the reduction temperature of the organometallic complex; a diluting step of diluting the pressurized fluid in a high-pressure vessel 3 by fluidizing high-pressure carbon dioxide containing no organometallic complex at the temperature below the reduction of the organometallic complex in the high-pressure vessel 3; and a reducing step of reducing the organometallic complex impregnated in the polymeric base material 21 while high-pressure carbon dioxide is contained in the high-pressure vessel 3.

Description

  The present invention relates to a plating pretreatment method for forming a plating film on a polymer substrate by electroless plating treatment.

  Conventionally, an electroless plating method is known as a method of forming a plating film on the surface of a polymer substrate. This electroless plating method uses a catalytic chemical reaction to reduce metal ions to form a plating film on the object to be plated, so that the object to be plated itself has a reducing agent reducing action. Except for the case where the catalytic activity is exhibited, it is ensured that the metal material having catalytic activity is stably and uniformly adhered to the inside of the surface of the object to be plated, thereby ensuring the adhesion of the finally obtained plated film. It is necessary to do. Therefore, when the object to be plated is a polymer substrate made of a resin material, an etching solution containing an oxidant having a large environmental load such as hexavalent chromic acid or permanganic acid is used before electroless plating. An etching process for roughening the surface of the molecular substrate is performed to form irregularities on the surface of the polymer substrate, and a metal substance serving as a catalyst nucleus is imparted to the irregularities. Moreover, the polymer substrate immersed in such an etching solution, that is, a polymer substrate to which electroless plating can be applied is limited to a polymer substrate containing an ABS resin. This is because the ABS-based resin contains a butadiene rubber component that is selectively eroded by the etching solution, while other resins have few components that are selectively eroded by such an etching solution, and the surface of the resin is not easily eroded. This is because unevenness is difficult to be formed. Therefore, when performing electroless plating on polymer substrates containing polycarbonate resin other than ABS resin as a resin component, plating grade products containing ABS resin and elastomer are used to enable electroless plating. Has been. However, in such a plating grade product, deterioration of physical properties such as heat resistance of the main material cannot be avoided.

  In order to solve the above problems, there is a surface modification method in which a catalyst component containing a metal serving as a plating catalyst is infiltrated into a polymer base material using carbon dioxide in a supercritical state before electroless plating treatment. Proposed. For example, the plating catalyst is introduced by bringing a molded resin molded body into contact with a pressurized fluid obtained by dissolving a metal simple substance or a metal-containing compound as a plating catalyst in supercritical carbon dioxide in a high-pressure vessel. A plating pretreatment method for obtaining a resin molded body has been proposed (Patent Document 1). However, since the above metals alone have poor solubility in supercritical carbon dioxide, a sufficient amount of plating catalyst for forming a plating film cannot be introduced into the polymer substrate, and stable plating is performed. It is difficult to form a film. For this reason, for example, a pressurized fluid in which an organometallic complex is dissolved in high-pressure carbon dioxide in a supercritical state or a subcritical state is brought into contact with the polymer fiber substrate in a high-pressure vessel and introduced into the polymer fiber substrate by contact. A plating pretreatment method has been proposed in which the organometallic complex is reduced to a plating catalyst (Patent Document 2).

  High-pressure carbon dioxide such as supercritical carbon dioxide is a fluid that has both permeability as a gas and solvent properties as a liquid, and organometallic complexes are more soluble in high-pressure carbon dioxide than single metals. By using a pressurized fluid in which the organometallic complex is dissolved in high-pressure carbon dioxide, the organometallic complex dissolved in the pressurized fluid penetrates into the polymer substrate as the pressurized fluid penetrates. Thereby, the organometallic complex can be introduced into the polymer substrate without performing an etching treatment. Therefore, according to the above method, it is not necessary to use an oxidizing agent such as hexavalent chromic acid having a large environmental load, and also for a polymer base material made of a resin material with few components eroded by the etching solution, A plating film can be formed by electroless plating.

JP 2001-316832 A

JP 2007-56287 A

  By the way, in the electroless plating treatment, the organometallic complex has lower catalytic activity than the metal substance. Therefore, as described in Patent Document 2, when using an organometallic complex infiltrated into a polymer substrate as a plating catalyst, it is necessary to activate the organometallic complex. Specifically, in Patent Document 2, a pressurized fluid and a polymer fiber substrate are brought into contact with each other in a high-pressure vessel heated to a temperature higher than the reduction temperature of the organometallic complex, or a reducing agent is supplied into the high-pressure vessel. Thus, the organometallic complex is reduced to a metal substance. Since the metal material thus reduced has low solubility in high-pressure carbon dioxide, the metal material can be immobilized inside the polymer substrate.

  However, when the reduction treatment is performed in a state where the pressurized fluid containing the organometallic complex is contained in the high-pressure vessel as described above, the free organometallic complex that has not penetrated the polymer substrate is also reduced. Become a metallic substance. Therefore, there is a problem that an expensive organometallic complex cannot be recovered and the cost is increased. Further, when the organometallic complex in the pressurized fluid is reduced to become a metal substance, the metal substance is poor in solubility in high-pressure carbon dioxide, so it is difficult to penetrate the metal substance into the polymer substrate, An amount of the plating catalyst necessary for the plating reaction cannot be secured inside the polymer substrate. Furthermore, according to the above activation step, a large amount of a metal substance produced by reduction of the free organometallic complex in the pressurized fluid adheres to the outermost surface of the polymer substrate. Therefore, when an electroless plating process is performed on such a polymer substrate with a large amount of metal material attached to the outermost surface, the plating film grows from the outermost surface of the polymer substrate with less anchor effect, and adhesion There is a problem that an excellent plating film cannot be formed.

  From the above viewpoint, it is conceivable to provide a depressurization step for discharging the pressurized fluid from the high-pressure vessel and opening the high-pressure vessel to the atmosphere after the organometallic complex is infiltrated into the polymer base material and before the reduction treatment. In this case, since the pressurized fluid is discharged before the reduction treatment of the organometallic complex, the organometallic complex can be recovered from the discharged pressurized fluid. However, the organometallic complex has high solubility in high-pressure carbon dioxide, but has low affinity for the polymer substrate. In addition, it is difficult for the organometallic complex to permeate the polymer base material unless it is under high pressure conditions where high pressure carbon dioxide exists. Therefore, when discharging the pressurized fluid from the high-pressure vessel, the organometallic complex that has penetrated into the polymer substrate escapes from the polymer substrate, and together with the pressurized fluid, the amount of organometallic complex required for the plating reaction Will also be discharged. As a result, there is a problem that the amount of the organometallic complex inside the polymer substrate is lowered. In particular, when a thin polymer substrate such as a polymer fiber substrate or a sheet-like resin molded body is used as an object to be plated, it can penetrate into these polymer substrates due to its thickness. The amount of organometallic complex is necessarily reduced. In addition, when a thin polymer substrate as described above is used as an object to be plated, when the high-pressure vessel is opened to the atmosphere after infiltrating the organometallic complex, the polymer substrate is released along with the discharge of the pressurized fluid. Organometallic complexes that have penetrated into the material are more easily detached. Therefore, when these thin polymer base materials are used, there is a problem that only a plating film having extremely low adhesion can be formed.

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is not found in a polymer substrate surface-modified using a pressurized fluid in which an organometallic complex is dissolved in high-pressure carbon dioxide. To provide a plating pretreatment method capable of recovering an organometallic complex unnecessary for a plating reaction contained in a pressurized fluid and forming a plating film having excellent adhesion when performing an electrolytic plating process. It is in.

In the present invention, in a high-pressure vessel, a polymer substrate and a pressurized fluid containing an organometallic complex and high-pressure carbon dioxide are contacted at a temperature lower than the reduction temperature of the organometallic complex, and the organometallic complex is Infiltrate the polymer substrate,
A high-pressure carbon dioxide containing no organometallic complex is flowed to a high-pressure vessel in which the polymer base material and the pressurized fluid are in contact with each other at a temperature lower than the reduction temperature of the organometallic complex, and the added pressure in the high-pressure vessel is increased. Dilute the pressurized fluid,
It is a pretreatment method for plating a polymer base material, in which the organometallic complex infiltrated into the polymer base material is reduced in a state where high pressure carbon dioxide is contained in the high pressure container.

  According to the pretreatment method described above, the polymer base material and the pressurized fluid containing the organometallic complex are brought into contact with the polymer base material at a temperature lower than the reduction temperature of the organometallic complex in the high-pressure vessel. The complex can penetrate. The pressurized fluid in the high-pressure vessel is diluted by flowing high-pressure carbon dioxide that does not contain the organometallic complex at a temperature lower than the reduction temperature of the organometallic complex in the high-pressure vessel to which the pressurized fluid is supplied. Thus, the unreduced organometallic complex that has not penetrated into the polymer substrate can be recovered from the discharged pressurized fluid. In addition, since the high-pressure carbon dioxide is used for diluting the pressurized fluid, the organometallic complex that has penetrated into the polymer substrate accompanying the discharge of the pressurized fluid is compared with the case where the high-pressure vessel is opened to the atmosphere. Desorption can be suppressed. Furthermore, the amount of the organometallic complex adhering to the outermost surface of the polymer substrate can be reduced by flowing high-pressure carbon dioxide not containing an organometallic complex into the high-pressure vessel. After the dilution, the organometallic complex that has penetrated the polymer base material is reduced in a state in which the high pressure carbon dioxide is contained in the high pressure container without opening the high pressure container to the atmosphere. There is little desorption of the organometallic complex that has penetrated into the molecular substrate. Thereby, the metal substance which becomes a plating catalyst with high concentration inside the polymer substrate can be fixed. Therefore, if the pre-treated polymer substrate is subjected to electroless plating, the growth of the plating film from the outermost surface is suppressed, and a plating film having high adhesion grown from the inside of the polymer substrate is formed. can do.

  In the pretreatment method, as the polymer substrate, a polymer fiber substrate or a sheet-like resin molded body can be used. Since these polymer substrates are thin, the organometallic complex cannot penetrate a large amount into the polymer substrate. However, according to the present invention, the adhesion to such a polymer substrate is improved. An excellent plating film can be formed.

  In the pretreatment method, the polymer substrate and the reducing agent may be contacted in advance before the polymer substrate and the pressurized fluid are contacted. According to the pretreatment method, when the organometallic complex penetrates into the polymer substrate, the organometallic complex is reduced by the reducing agent previously applied to the interior of the polymer substrate. It can be immobilized inside the polymer substrate.

  As described above, according to the plating pretreatment method of the present invention, when a surface-modified polymer base material is subjected to electroless plating using a pressurized fluid in which an organometallic complex is dissolved in high-pressure carbon dioxide. Moreover, a plating film having excellent adhesion can be formed at low cost.

FIG. 1 is a schematic diagram showing a manufacturing apparatus used in an embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of a wound body used in an embodiment of the present invention. FIG. 3 is a schematic diagram showing another example of the wound body used in the embodiment of the present invention. FIG. 4 is a scanning electron micrograph of the cross section of the plating film formed in Example 3 of the present invention. FIG. 5 is an enlarged photograph of FIG. FIG. 6 is a scanning electron micrograph of the cross section of the plating film formed in Comparative Example 2. FIG. 7 is an enlarged photograph of FIG.

  Hereinafter, the pretreatment method for plating the polymer substrate according to the present embodiment will be specifically described.

  In the pretreatment method for plating a polymer substrate according to the present embodiment, a pressurized fluid containing an organometallic complex and high-pressure carbon dioxide is supplied into a high-pressure vessel in which the polymer substrate is disposed. The polymer substrate and the pressurized fluid are brought into contact with each other at a temperature lower than the reduction temperature of the organometallic complex, and a permeation step is performed to permeate the organometallic complex into the polymer substrate. Although the metal material used as the plating catalyst has low solubility in high-pressure carbon dioxide, the organometallic complex has high solubility in high-pressure carbon dioxide, so use a pressurized fluid in which the organometallic complex is dissolved in high-pressure carbon dioxide. Thus, the organometallic complex can be efficiently infiltrated into the polymer substrate without performing an etching process using an etching solution containing an oxidizing agent such as hexavalent chromic acid having a large environmental load. In addition, by using high-pressure carbon dioxide, the organometallic complex can be infiltrated into the inside of the polymer substrate, so that a polymer film made of a resin material having no etching component can be plated with an electroless plating process. Can be formed. Furthermore, since the contact between the polymer substrate and the pressurized fluid is performed below the reduction temperature of the organometallic complex, the organometallic complex is polymerized in an unreduced state in which the organometallic complex is not reduced to a metal substance. It can penetrate into the substrate. Thereby, the organometallic complex unnecessary for the plating reaction can be recovered by allowing high-pressure carbon dioxide that does not contain the organometallic complex later to flow in the high-pressure vessel below the reduction temperature of the organometallic complex.

  The organometallic complex is not particularly limited as long as it is soluble in high-pressure carbon dioxide in the permeation step and can be reduced to a metal substance that becomes a plating catalyst in the reduction step. Specifically, organometallic complexes containing metals such as palladium, platinum, nickel, copper, and silver can be given. Examples of such organometallic complexes include bis (cyclopentadienyl) nickel, bis (acetylacetonato) palladium (II), dimethyl (cyclooctadienyl) platinum (II), hexafluoroacetylacetonatopalladium ( II), hexafluoroacetylacetonatohydrate copper (II), hexafluoroacetylacetonatoplatinum (II), hexafluoroacetylacetonato (trimethylphosphine) silver (I), dimethyl (heptafluorooctaneconate) silver (AgFOD) ) And the like. These may be used alone or in combination. Among these, organometallic complexes having fluorine as a ligand have excellent solubility in high-pressure carbon dioxide, and the solubility in high-pressure carbon dioxide is more than two orders of magnitude compared to organometallic complexes that do not contain fluorine. high. Therefore, by using such an organometallic complex having fluorine as a ligand, the concentration of the organometallic complex in the high-pressure vessel can be increased for several minutes to several tens of minutes. In addition, by using such an organometallic complex having excellent solubility, a pressurized fluid in which the organometallic complex is dissolved can be prepared without using high-pressure carbon dioxide in a supercritical state. Thereby, while being able to shorten the processing time in an infiltration process, the burden in a manufacturing apparatus can be reduced.

As high-pressure carbon dioxide, carbon dioxide in a liquid state, a gas state, or a supercritical state can be used. By using such high-pressure carbon dioxide, the organometallic complex can be infiltrated into the polymer substrate under high-pressure conditions. In the present embodiment, carbon dioxide in a supercritical state may be used as high-pressure carbon dioxide, but as described above, an organometallic complex having excellent solubility in high-pressure carbon dioxide is used as a catalyst component. Therefore, high-pressure carbon dioxide that is not in a supercritical state can be used. Therefore, the high-pressure carbon dioxide may be carbon dioxide pressurized to a critical point (supercritical state where the temperature is 31 ° C. or higher and the pressure is 7.38 MPa or higher), or pressurized at a pressure lower than the critical point. Carbon dioxide may be used. More specifically, the pressure of the high-pressure carbon dioxide is preferably 5 to 30 MPa. When the pressure is less than 5 MPa, the density of high-pressure carbon dioxide tends to decrease. On the other hand, when the pressure is higher than 30 MPa, a high pressure resistant manufacturing apparatus is required, resulting in an increase in cost. The temperature of the high-pressure carbon dioxide is preferably lower than the reduction temperature of the organometallic complex in order to prevent the organometallic complex from being reduced in the pressurized fluid. Furthermore, the density of the high-pressure carbon dioxide is preferably 0.10 to 0.99 g / cm ³ .

  In preparing a pressurized fluid in which an organometallic complex is dissolved in high-pressure carbon dioxide, a conventionally known method can be used. For example, liquid carbon dioxide is pressurized by a pressurizing means such as a pump, the pressurized high-pressure carbon dioxide is supplied to a dissolution tank in which an organometallic complex is charged, and the organometallic complex and the high-pressure carbon dioxide are combined. Pressurized fluids can be prepared by mixing below the reduction temperature. The concentration of the organometallic complex in the pressurized fluid is not particularly limited, but is preferably less than a saturated concentration, and more preferably 30 to 1,000 mg / L. If the concentration of the organometallic complex is too high, the organometallic complex tends to precipitate from the pressurized fluid due to a pressure change in the high-pressure vessel. Since the deposited organometallic complex is not dissolved in the pressurized fluid, it does not penetrate into the polymer base material and becomes an unnecessary organometallic complex. In addition, the amount of the organometallic complex adhering to the outermost surface of the polymer substrate increases, and the plating film grows from the outermost surface of the polymer substrate, so that the adhesion tends to decrease.

  The resin material constituting the polymer base material is not particularly limited, and any resin material can be used. For example, when a resin molded body is used as the polymer substrate, a thermoplastic resin, a thermosetting resin, an ultraviolet curable resin, or the like can be used as the resin material constituting the resin molded body. Among these, a thermoplastic resin is preferable. The type of the thermoplastic resin is arbitrary, and both amorphous and crystalline can be used. For example, polyester resin; nylon resin; polypropylene resin; polyamide resin; polymethyl methacrylate resin; polycarbonate resin; amorphous polyolefin resin; polyetherimide resin; polyethylene terephthalate resin; A polyamidoimide resin; a polyphthalamide resin; a polyphenylene sulfide resin; a biodegradable plastic such as polylactic acid can be used. Further, a composite material of these resins may be used. Furthermore, resin materials obtained by kneading these resins with various inorganic fillers such as glass fibers, carbon fibers, nanocarbons, and minerals can also be used. Among these, nylon resins that are excellent in permeability of pressurized fluid are preferable. For example, when a polymer fiber substrate is used as the polymer substrate, the fiber material constituting the polymer fiber substrate includes natural fibers such as plant fibers and animal fibers; regenerated fibers such as rayon and cupra; acetate Semi-synthetic fibers such as; synthetic fibers and the like. Synthetic fibers include nylon fibers; aramid fibers; polyacrylic fibers; polyester fibers; polyurethane fibers; polyolefin fibers such as polyethylene and polypropylene; polyvinyl chloride fibers; polyvinylidene chloride fibers; Examples include fibers. These may be used alone or in combination. Among these, at least one selected from the group consisting of nylon fibers and aramid fibers excellent in permeability of pressurized fluid and electroless plating solution is preferable. Examples of such nylon fibers include nylon 6, nylon 46, nylon 66, nylon 11, nylon 12, nylon MXD6, nylon 6T, nylon 9T, and the like. As the aramid fiber, any of a meta aramid fiber and a para aramid fiber can be used without limitation. Examples of the meta-aramid fiber include polymetaphenylene isophthalamide fiber (for example, Nomex manufactured by DuPont). Examples of the para-aramid fiber include polyparaphenylene terephthalamide fiber (for example, Kevlar manufactured by Toray DuPont), copolyparaphenylene-3,4'-diphenyl ether terephthalamide fiber (for example, manufactured by Teijin Ltd., Technora).

  In particular, the pretreatment method of the present embodiment is highly effective when a polymer fiber substrate or a sheet-like resin molded body is used as the polymer substrate. That is, since these polymer base materials are thin, the amount of the organometallic complex that can permeate the inside of the polymer base material is smaller than that of a thick plate-shaped resin molded body. In addition, even if the organometallic complex penetrates into the inside of the polymer substrate, after the infiltration process, when the pressurized fluid is discharged and the high-pressure vessel is opened to the atmosphere, the organic material that has penetrated into the inside of the polymer substrate together with the pressurized fluid. Most of the metal complex is easily discharged. As a result, the amount of the organometallic complex necessary for the plating reaction cannot be secured inside these thin polymer substrates, and it is difficult to form a plating film having excellent adhesion. On the other hand, in the pretreatment method of the present embodiment, high-pressure carbon dioxide is flowed into the high-pressure vessel after the infiltration step, so that even if the pressurized fluid is diluted, the organometallic complex is a thin-walled polymer substrate. The detachment of the organometallic complex from the thin polymer base material can be suppressed as compared with the case where it remains inside and the high-pressure vessel is opened to the atmosphere. Therefore, even when a polymer fiber substrate or a sheet-like resin molded product is used as a polymer substrate, a polymer substrate having a high concentration of an organometallic complex therein can be obtained. For this reason, according to the pretreatment method of the present embodiment, for example, the polymer fiber base material having a fiber diameter of 50 μm or less and the sheet-like resin molded body having a thickness of 200 μm or less have high adhesion. A plating film can be formed.

  In the present embodiment, the polymer substrate may be provided with a reducing agent before the infiltration step. Organic that permeates into the polymer substrate in the infiltration step by providing a reducing agent application step in which the reducing agent is added by bringing the polymer substrate into contact with the reducing agent-containing aqueous solution containing the reducing agent before the infiltration step. The metal complex comes into contact with the reducing agent-containing aqueous solution, and a part of the organometallic complex is reduced to a metal substance having poor solubility in high-pressure carbon dioxide inside the polymer substrate. Therefore, even if high-pressure carbon dioxide has permeated into the polymer base material in the permeation step or the subsequent dilution step, the detachment of the organometallic complex from the polymer base material can be reduced. And since the free organometallic complex in the pressurized fluid which has not penetrated the polymer base material does not come into contact with the reducing agent, it is not reduced to a metallic substance. Therefore, by diluting the pressurized fluid in the high-pressure vessel in the dilution step, unnecessary organometallic complexes can be recovered, and a plating reaction can be efficiently generated in the electroless plating step. .

  The said reducing agent provision process can be performed by immersing a polymeric base material in the reducing agent containing aqueous solution containing a reducing agent. As such a reducing agent, the same reducing agent as used in the electroless plating process can be used. Specific examples include at least one selected from the group consisting of hypophosphorous acid, sodium hypophosphite, dimethylamine borane, hydrazine, formaldehyde, sodium borohydride, and phenols. A reducing agent provision process can be performed under a normal pressure. In addition, the reducing agent application step may be performed at normal temperature, or may be performed under heating in order to promote the penetration of the reducing agent-containing aqueous solution into the polymer substrate. When heating, although depending on the resin material constituting the polymer substrate, the temperature is preferably less than 100 ° C., which is the boiling point of water. The concentration of the reducing agent in the reducing agent-containing aqueous solution is not particularly limited because it depends on the type of reducing agent used and the type of resin material constituting the polymer substrate, but usually 0.1 to 10 vol. %. In the reducing agent application step, it is preferable to wash the polymer substrate with a cleaning liquid after bringing the polymer substrate into contact with the reducing agent-containing aqueous solution. Since the reducing agent attached to the surface of the polymer substrate is removed by washing, the reduction of the organometallic complex on the outermost surface of the polymer substrate is suppressed in the permeation process, and from the outermost surface in the electroless plating process. Progress of the plating reaction can be suppressed. Specific examples of such cleaning liquid include water and alcohol.

  In the infiltration step, the method for bringing the polymer substrate into contact with the pressurized fluid containing the organometallic complex is not particularly limited as long as the organometallic complex can be infiltrated into the polymer substrate. For example, by placing a polymer substrate in a high-pressure vessel, supplying a pressurized fluid in which an organometallic complex is dissolved in high-pressure carbon dioxide to the high-pressure vessel, and contacting the polymer substrate with the pressurized fluid, The metal complex can penetrate into the polymer substrate. When a polymer fiber substrate or a sheet-shaped resin molded body is used as the polymer substrate, a wound body in which the polymer substrate is wound around a cylindrical mesh member having a large number of through holes is arranged in a high-pressure container. May be. As such a cylindrical mesh member, an aluminum mesh member or a SUS mesh member can be used. Moreover, when using these polymer base materials, you may arrange | position the wound body which wound the polymer base material through the separator formed from the inorganic substance in a high pressure container. Specific examples of the separator formed of such an inorganic material include an aluminum mesh sheet, a SUS mesh sheet, and a glass cloth. Since the pressurized fluid can pass through these separators, the highly diffusible pressurized fluid uniformly diffuses and permeates through the separator to the entire surface of the polymer substrate. Thereby, while being able to reduce the damage to the polymer base material obtained, an organometallic complex can be permeated in the polymer base material with little aggregation.

  In the infiltration step, the pressure in the high-pressure vessel depends on the pressure of the pressurized fluid supplied, but is preferably 5 to 30 MPa. By bringing the polymer substrate and the pressurized fluid into contact with each other under such a high pressure condition, the organometallic complex can be efficiently penetrated into the polymer substrate. In the infiltration step, the temperature in the high-pressure vessel when the polymer substrate and the pressurized fluid containing the organometallic complex are brought into contact is lower than the reduction temperature of the organometallic complex as described above, and the organometallic complex It is preferably 10 ° C. or more lower than the reduction temperature. The reduction temperature of the organometallic complex can be determined by measuring the decomposition start temperature of the organometallic complex using a differential scanning calorimeter (DSC) in a nitrogen atmosphere. When the temperature in the high-pressure vessel is equal to or higher than the reduction temperature of the organometallic complex, when the pressurized fluid is supplied into the high-pressure vessel, the free organometallic complex in the pressurized fluid becomes soluble in high-pressure carbon dioxide. Since it is reduced to an inferior metal substance, the concentration of the organometallic complex in the pressurized fluid is reduced. Therefore, the amount of the organometallic complex that penetrates the polymer substrate is reduced. In addition, since the free organometallic complex is reduced to a metal substance, the recovery rate of the organometallic complex is reduced. Furthermore, when the free organometallic complex in the pressurized fluid is reduced to the above metal material, the polymer substrate in a state in which a large amount of the reduced metal material adheres to the outermost surface of the polymer substrate. Therefore, the plating film easily grows from the outermost surface of the polymer base material in the subsequent electroless plating treatment, and therefore, it is difficult to form the plating film from the inside of the polymer base material having a high anchor effect. . For this reason, the adhesiveness of a plating film falls.

  Next, the high-pressure vessel containing the polymer base material infiltrated with the organometallic complex as described above is allowed to flow high-pressure carbon dioxide not containing the organometallic complex, and the high-pressure vessel is less than the reduction temperature of the organometallic complex. A dilution process for diluting the pressurized fluid is performed.

  By flowing high-pressure carbon dioxide that does not contain the organometallic complex into the high-pressure vessel after the infiltration process, the pressurized fluid in the high-pressure vessel and the high-pressure carbon dioxide that does not contain the organometallic complex are mixed and added to the high-pressure vessel in the high-pressure vessel. While the concentration of the organometallic complex contained in the pressurized fluid is diluted, the pressurized fluid containing the free organometallic complex that does not penetrate the polymer substrate is discharged from the high-pressure vessel. Since both the infiltration step and the dilution step are performed below the reduction temperature of the organometallic complex, the organometallic complex contained in the discharged pressurized fluid is recovered in an unreduced state that has not been reduced to a metallic substance. The For this reason, the recovered organometallic complex can be reused, thereby reducing the manufacturing cost.

  Moreover, since the concentration of the organometallic complex contained in the pressurized fluid in the high-pressure vessel is diluted by flowing high-pressure carbon dioxide that does not contain the organometallic complex in the high-pressure vessel, The amount of the organometallic complex attached can be reduced. Thereby, the density | concentration of an organometallic complex becomes high inside the outermost surface of a polymer base material, and it can raise | generate a plating reaction using the organometallic complex which osmose | permeated the inside of a polymer base material. That is, the adhesion of the plating film is due to a physical anchor effect caused by the plating film biting into the resin component. Therefore, in order to obtain high adhesion, it is necessary to grow a plating film using the plating catalyst inside the surface as a catalyst nucleus. However, when the polymer substrate is immersed in the electroless plating solution, the electroless plating solution penetrates from the surface of the polymer substrate, so that a large amount of plating catalyst adheres to the outermost surface of the polymer substrate. If so, the plating reaction starts before the electroless plating solution sufficiently penetrates into the polymer substrate. Therefore, although the density of the plating film on the outermost surface of the polymer base material is increased, it is difficult to form a plating film in a state where the resin component is bitten inside the polymer base material. As a result, a high anchor effect cannot be obtained, and the plating reaction tends to be uneven. For this reason, the adhesion strength of the obtained plating film is likely to be reduced, and variations in the adhesion strength are likely to occur. On the other hand, if the high-pressure carbon dioxide not containing an organometallic complex is flowed into the high-pressure vessel after the infiltration step as described above, the concentration of the organometallic complex contained in the pressurized fluid in the high-pressure vessel is diluted. Therefore, the amount of the organometallic complex existing on the outermost surface of the polymer substrate can be reduced, and a polymer substrate containing more organometallic complex inside than the outermost surface can be obtained. Therefore, if this polymer substrate is subjected to reduction treatment to reduce the organometallic complex to a metal substance, a plating film can be grown from the inside of the polymer substrate. Thereby, it is possible to form a plating film having excellent adhesion even to a polymer fiber substrate or a sheet-like resin molded body in which it is difficult to permeate a large amount of the organometallic complex.

  The conditions for flowing high-pressure carbon dioxide that does not contain an organometallic complex into the high-pressure vessel are not particularly limited as long as the concentration of the organometallic complex contained in the pressurized fluid in the high-pressure vessel can be diluted. The ratio (recovery rate) of the recovery amount of the organometallic complex recovered by the flow of high-pressure carbon dioxide not containing the organometallic complex in the dilution step to the supply amount of the organometallic complex is 25 to 90% by mass. Thus, it is preferred to dilute the pressurized fluid. In particular, when the recovery rate is 50 to 75% by mass, a plating film having higher adhesion can be formed uniformly. If the recovery rate is less than 25% by mass, a large amount of the organometallic complex remains in the high-pressure vessel, so that the free organometallic complex that has not penetrated the polymer base material in the subsequent reduction step is reduced to a metal substance, The organometallic complex cannot be efficiently recovered. In addition, since the organometallic complex is reduced in a state where a large amount of the organometallic complex adheres to the outermost surface of the polymer substrate, a plating reaction occurs from the outermost surface, and the adhesion of the obtained plating film tends to be reduced. . On the other hand, when the recovery rate is more than 95% by mass, the organometallic complex that has penetrated into the polymer substrate in the dilution step is detached in a large amount from the polymer substrate, and the organometallic complex inside the polymer substrate is removed. The amount of is reduced. For this reason, the plating reaction does not occur sufficiently, and the adhesion of the plating film tends to decrease.

  As the high-pressure carbon dioxide flowing in the high-pressure vessel in the dilution step, one having the same pressure as the high-pressure carbon dioxide used in the permeation step can be used. Further, the temperature in the high-pressure vessel in the dilution step is lower than the reduction temperature of the organometallic complex as described above, and is preferably lower by 10 ° C. or more than the reduction temperature of the organometallic complex. When the temperature in the high-pressure vessel is equal to or higher than the reduction temperature of the organometallic complex, the free organometallic complex that has not penetrated the polymer substrate in the high-pressure vessel is reduced to a metal substance, so that it is the same as in the infiltration process. In addition, the recovered amount of the organometallic complex is reduced, which is uneconomical and the adhesion of the plating film tends to be lowered. In addition, it is preferable that the temperature in the high-pressure vessel in the dilution step is maintained at the temperature in the high-pressure vessel in the infiltration step. In particular, when the temperature in the high-pressure vessel in the dilution step is lower than the temperature in the high-pressure vessel in the infiltration step, the pressure in the high-pressure vessel is reduced, and the organometallic complex that has penetrated into the polymer substrate is likely to be detached. Become.

  Next, after the high-pressure carbon dioxide that does not contain the organometallic complex is flowed in the high-pressure vessel as described above, the organic material that has been permeated into the polymer substrate in a state where the high-pressure carbon dioxide is contained in the high-pressure vessel. A reduction process for reducing the metal complex to a metal substance is performed. As a result, the organometallic complex that has permeated the inside of the polymer substrate is reduced to a metal material, and the reduced metal material can be immobilized inside the polymer substrate. In addition, since the reduction treatment is performed under pressure in a state where high-pressure carbon dioxide is contained in the high-pressure vessel, the organometallic complex accompanying the discharge of high-pressure carbon dioxide is higher than when a conventional high-pressure vessel is opened to the atmosphere. Desorption from the molecular substrate can be suppressed.

  The reduction step may be performed by heating the high-pressure vessel to a temperature equal to or higher than the reduction temperature of the organometallic complex, or may be performed by supplying a reducing agent to the high-pressure vessel. These reduction treatments may be used in combination. When performing the thermal reduction treatment, the temperature in the high-pressure vessel is not limited as long as it is equal to or higher than the reduction temperature of the organometallic complex, but is preferably 10 ° C. or higher than the reduction temperature of the organometallic complex in order to promote the reduction. . In addition, when performing a thermal reduction process, in order to suppress the damage to the resin material of a polymer base material, it is preferable that the temperature in a high pressure container is less than the decomposition start temperature of a resin material. Moreover, when performing the reduction process by a reducing agent, as a reducing agent, the thing similar to the reducing agent used at the reducing agent provision process mentioned above can be used. Among these, when forming a nickel-phosphorous plating film, the reducing agent is preferably at least one selected from the group consisting of hypophosphorous acid and sodium hypophosphite. When performing a reduction treatment with a reducing agent, it is necessary to supply high-pressure carbon dioxide in which the reducing agent is dissolved into the high-pressure vessel. However, the reducing agent does not provide the reducing action of the organometallic complex unless water is present in the surroundings, whereas the solubility of water in high-pressure carbon dioxide is low. Therefore, it becomes difficult to dissolve the aqueous solution containing the reducing agent in high-pressure carbon dioxide. For this reason, when performing a reduction process with a reducing agent, it is preferable to supply the reducing agent containing fluid which dissolved the reducing agent, water, and alcohol in the high pressure carbon dioxide to a high pressure container. Alcohol is highly compatible with water, has excellent solubility in high-pressure carbon dioxide, and also has excellent penetrability into the polymer substrate, so that the reducing agent can smoothly penetrate into the polymer substrate. The organometallic complex can be efficiently reduced to a metal substance inside the polymer substrate. The type of alcohol is arbitrary, but considering the permeability to the polymer substrate, an alcohol having a low surface tension is desirable. Specifically, an alcohol having a surface tension lower than the surface tension of water (73 dyn / cm) at 20 ° C. is preferable, and an alcohol having a surface tension of 40 dyn / cm or less is more preferable. Moreover, since it will become difficult to penetrate | invade a polymer base material when the molecular weight of alcohol is large, the alcohol which has a molecular weight of 150 or less is preferable, and the alcohol which has a molecular weight of 120 or less is more preferable. Specific examples of alcohols that satisfy these conditions include ethanol (molecular weight: 46.1, surface tension: 22.3 dyn / cm), 1-propanol (molecular weight: 60.1, surface tension: 23.8 dyn). / Propanol), 2-propanol (molecular weight: 60.1, surface tension: 21.7 dyn / cm), 2-methoxyethanol (molecular weight: 76.1, surface tension: 31.8 dyn / cm), 2-ethoxyethanol ( Molecular weight: 90.1, surface tension: 28.2 dyn / cm), 1-methoxy-2-propanol (molecular weight: 90.1, surface tension: 27.1 dyn / cm), 1-ethoxy-2-propanol (molecular weight: 104.2, surface tension: 25.9 dyn / cm), 1,3-butanediol (molecular weight: 90.1, surface tension: 37.8 dyn / cm), te t-butyl alcohol (molecular weight: 74.1, surface tension: 19.5 dyn / cm), 2- (2-ethoxyethoxy) ethanol (molecular weight: 134.2, surface tension: 31.3 dyn / cm), 1-propoxy -2-propanol (molecular weight: 118.2, surface tension: 25.9 dyn / cm), 2 (2-methoxypropoxy) propanol (molecular weight: 148.2, surface tension: 28.8 dyn / cm), and the like. These may be used alone or in combination. Although content of alcohol is arbitrary, 35-65 vol% is desirable with respect to the total amount of water and alcohol.

  The pressure in the high-pressure vessel in the reduction step is preferably 5 to 30 MPa in order to reduce the desorption of the organometallic complex from the polymer substrate.

  The metal material can be immobilized on the polymer substrate by the above pretreatment method, and a plating film can be formed by using this metal material as a plating catalyst. And according to the pretreatment method of the present embodiment, since the amount of the organometallic complex on the outermost surface of the polymer substrate is reduced by the dilution step, the polymer substrate is subjected to electroless plating treatment. A plating film having a high anchor effect grown from the inside can be formed.

  When performing an electroless plating treatment, a conventionally known plating solution can be used as the electroless plating solution. Specifically, for example, nickel-phosphorous plating solution, nickel-boron plating solution, palladium plating solution, copper plating solution, silver plating solution, cobalt plating solution and the like can be mentioned. The electroless plating solution preferably contains alcohol. By adding alcohol to the electroless plating solution, the surface tension of the electroless plating solution can be reduced, and the electroless plating solution penetrates smoothly into the polymer substrate even in electroless plating treatment under normal pressure. it can. In addition, since alcohol acts as a reducing agent that delays the growth of the plating film, the plating reaction on the outermost surface can be delayed when the electroless plating solution begins to permeate the surface of the polymer substrate. As a result, the formed electroless plating film grows inside the polymer substrate and has high adhesion strength. As the alcohol mixed in the electroless plating solution, the same alcohol as that used in the above reduction step can be used. The content of alcohol in the electroless plating solution is arbitrary, but is preferably 20 to 60 vol%.

  In the present embodiment, the electroless plating step can be performed by opening the high-pressure vessel to the atmosphere after the reduction step and immersing the polymer substrate taken out from the high-pressure vessel in an electroless plating solution under normal pressure. . That is, according to the pretreatment method of the present embodiment, the organometallic complex is reduced to a metal substance in the high-pressure vessel, and the metal substance has a higher affinity for the polymer substrate than the organometallic complex. And has low solubility in high-pressure carbon dioxide. For this reason, even when high-pressure carbon dioxide is discharged when the polymer substrate on which the metal substance is immobilized is taken out from the high-pressure vessel, the metal substance is hardly detached from the polymer substrate. Therefore, even if the polymer base material is taken out under normal pressure, the electroless plating treatment can be performed on the polymer base material in which the metal substance is fixed inside. The treatment temperature in the electroless plating process is not particularly limited as long as it is equal to or higher than the temperature at which the plating reaction occurs. In addition, since the electroless plating process can be performed under normal pressure as described above, it is not necessary to use high-pressure carbon dioxide. Therefore, it is possible to prepare a uniform plating bath with little change in the concentration of the electroless plating solution due to changes in pressure and temperature. Thereby, the dispersion | variation in a plating reaction can further be suppressed and the plating film with few dispersion | variation in adhesive force can be formed.

  In the present embodiment, the electroless plating step may be performed a plurality of times. For example, after performing an electroless plating treatment using an electroless plating solution containing the above-described alcohol, an electroless plating treatment using an aqueous electroless plating solution may be further performed. Further, an electrolytic plating film may be laminated on the electroless plating film.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited to these Examples.

[Example 1]
In this example, an aramid fiber (manufactured by Teijin Ltd., Technora, single fiber diameter: 12 μmφ) was used as the polymer substrate, and hexafluoroacetylacetonato palladium (II) was used as the organometallic complex.

(Reducing agent application process)
In the reducing agent application step, the polymer substrate is immersed in a reducing agent-containing aqueous solution containing a reducing agent. In this example, the aramid fiber was immersed in a hypophosphorous acid aqueous solution (hypophosphorous acid concentration: 6% by mass) at 80 ° C. for 30 minutes under normal pressure. After the immersion, the aramid fiber was taken out and the aramid fiber was ultrasonically washed in water for 1 minute in order to remove hypophosphorous acid adhering to the surface of the aramid fiber. Thereafter, in order to sufficiently remove the reducing agent adhering to the surface, the aramid fibers washed with water were immersed in ethanol at 70 ° C. under normal pressure for 15 seconds. After immersion, the aramid fiber was taken out, ethanol adhering to the aramid fiber surface was removed by dry air, and further dried in the air for 5 minutes.

(Penetration process)
Next, in order to infiltrate the organometallic complex into the polymer base material provided with the reducing agent as described above, a pressurized fluid in which the organometallic complex is dissolved in high-pressure carbon dioxide in the high-pressure vessel, the polymer base material, The permeation step is performed in which the is contacted at a temperature lower than the reduction temperature of the organometallic complex. FIG. 1 is a schematic diagram showing a manufacturing apparatus used in this example. As shown in FIG. 1, this manufacturing apparatus contains a liquid carbon dioxide cylinder 1, a syringe pump 2 for supplying high-pressure carbon dioxide by pressurizing liquid carbon dioxide to a predetermined pressure, and a polymer substrate. The high-pressure vessel 3, the pressurized fluid discharged from the high-pressure vessel 3, the separation / recovery machine 4 for separating the organometallic complex and the high-pressure carbon dioxide, and the collection tank for collecting the separated organometallic complex And 5. A manual needle valve V1 is disposed in the pipe L1 that connects the liquid carbon dioxide cylinder 1 and the syringe pump 2, and the pipe L2 that connects the syringe pump 2 and the high-pressure vessel 3 is in order from the upstream side. A pressure gauge P1, a check valve S, and a manual needle valve V2 are provided. Further, a branch pipe L3 is connected to the upstream side and the downstream side of the manual needle valve V2 to the pipe L2 connecting the syringe pump 2 and the high-pressure vessel 3, and the branch pipe L3 is sequentially connected from the upstream side. A manual needle valve V3, a dissolution tank 6 containing an organometallic complex, and a manual needle valve V4 are interposed. Furthermore, a pressure gauge P2, a manual needle valve V5, and a back pressure valve Vb are arranged in this order from the upstream side in the pipe L4 that connects the high-pressure vessel 3 and the separation and recovery machine 4.

  When supplying high-pressure carbon dioxide to the dissolution tank 6, the manual needle valve V1 of the liquid carbon dioxide cylinder 1 is opened, the syringe pump 2 is set to a constant pressure mode, and liquid carbon dioxide is supplied from the liquid carbon dioxide cylinder 1. Suction. Then, the pressure of carbon dioxide is increased by the syringe pump 2 so that the pressure detected by the pressure gauge P1 becomes a predetermined pressure. In this example, 4 to 6 MPa of liquid carbon dioxide was sucked from the liquid carbon dioxide cylinder 1 and the pressure of the carbon dioxide was increased by the syringe pump 2 so that the pressure detected by the pressure gauge P1 was 15 MPa. In the permeation process, the manual needle valve V2 is closed so that only high-pressure carbon dioxide is not supplied to the high-pressure vessel 3.

  After the pressure of carbon dioxide is increased to a predetermined pressure, the manual needle valve V3 is opened, and the high-pressure carbon dioxide is supplied to the dissolution tank 6 whose temperature is adjusted to a predetermined temperature. Thereby, the organometallic complex accommodated in the dissolution tank 6 is dissolved in high-pressure carbon dioxide, and a pressurized fluid containing the organometallic complex is prepared under pressure. In this example, 100 mg of hexafluoroacetylacetonato palladium (II) was placed in the dissolution tank 6, the temperature of the dissolution tank 6 was adjusted to 50 ° C., and the organometallic complex was stirred while stirring using a stirrer (not shown). Dissolved in high pressure carbon dioxide. In addition, in order to supply the pressurized fluid which the organometallic complex melt | dissolved uniformly to the high pressure vessel 3, stirring of the pressurized fluid in the dissolution tank 6 was continued during the infiltration process.

  As shown in FIGS. 1 and 2, a wound body 20 in which an aramid fiber 21 as a polymer base material is wound around a cylindrical mesh member 22 is accommodated in the high-pressure vessel 3. The cylindrical mesh member 22 has a large number of through holes on the side surface of the cylindrical portion, and is configured such that the pressurized fluid that has permeated the inside of the cylindrical mesh member 22 is also in contact with the surface of the polymer base material. Has been. In this example, an aramid fiber provided with a reducing agent was cut into a length of 10 m, and this was wound around a cylindrical mesh member made of SUS (diameter: 1.5 cmφ, length: 10 cm). 20 was placed in the high-pressure vessel 3. The high-pressure vessel 3 includes a temperature controller (not shown), whereby the temperature of the high-pressure vessel 3 is adjusted below the reduction temperature of the organometallic complex. In the present example, the temperature of the high-pressure vessel 3 was adjusted to 50 ° C., which is 10 ° C. or more lower than 73 ° C., which is the reduction temperature of hexafluoroacetylacetonato palladium (II).

  When supplying the pressurized fluid to the high-pressure vessel 3, the manual needle valve V4 is opened. As a result, a pressurized fluid having a constant pressure is supplied to the high-pressure vessel 3, the pressurized fluid comes into contact with the polymer substrate in the high-pressure vessel 3, and the organometallic complex penetrates into the polymer substrate. In this example, a pressurized fluid having a pressure of 15 MPa was supplied to the high-pressure vessel 3, and the pressurized fluid and the polymer substrate were brought into contact with each other for 30 minutes in the high-pressure vessel 3 having a pressure of 15 MPa.

(Dilution process)
Next, after the infiltration step, high-pressure carbon dioxide that does not contain the organometallic complex is flowed into the high-pressure vessel containing the pressurized fluid at a temperature lower than the reduction temperature of the organometallic complex, A dilution step for diluting is performed.

  In order to dilute the pressurized fluid in the high-pressure vessel 3, first, the manual needle valves V3 and V4 of the branch pipe L3 are closed, and are arranged in the pipes L2 and L4 on the upstream side and downstream side of the high-pressure vessel 3. Open the manual needle valves V2 and V5. Moreover, the syringe pump 2 was changed from the constant pressure mode to the constant flow rate mode, and the high-pressure carbon dioxide not containing the organometallic complex below the reduction temperature of the organometallic complex was adjusted to a temperature below the reduction temperature of the organometallic complex. The liquid is sent to the high-pressure vessel 3 for a certain period of time. At this time, since the syringe pump 2 is controlled in the constant flow rate mode, the pressure in the high-pressure vessel 3 is increased by the supplied high-pressure carbon dioxide. Therefore, the back pressure valve Vb is set to a predetermined pressure so that the pressurized fluid corresponding to the pressure increase is discharged. Thereby, in a state where the pressure in the high-pressure vessel 3 is kept constant, the pressurized fluid containing the organometallic complex in the high-pressure vessel 3 is diluted with the high-pressure carbon dioxide not containing the organometallic complex, and free organic The pressurized fluid containing the metal complex is discharged from the high-pressure vessel 3 to the separation / recovery machine 4. In this example, the pressure of the back pressure valve Vb was set to 15 MPa, and high-pressure carbon dioxide at 10 ° C. was fed at a flow rate of 10 mL / min to the high-pressure vessel 3 that was temperature-controlled at 50 ° C. in the same manner as the infiltration step. At this time, the recovered amount of the organometallic complex recovered in the recovery tank 5 was weighed.

(Reduction process)
Next, after the dilution step, a reduction step of reducing the organometallic complex that has permeated the polymer base material is performed under pressure in which high-pressure carbon dioxide is contained in the high-pressure vessel. In this example, a thermal reduction treatment was performed in which the high-pressure vessel 3 was heated to a temperature higher than the reduction temperature of the organometallic complex.

  The thermal reduction treatment can be performed by changing the syringe pump 2 again from the constant flow rate mode to the constant pressure mode and heating the high-pressure vessel 3. At this time, since the pressure in the high-pressure vessel 3 increases as the temperature rises, the back pressure valve Vb is set to a predetermined pressure so that high-pressure carbon dioxide corresponding to the pressure increase is discharged. Thereby, the pressure in the high-pressure vessel 3 is kept constant. In this example, the temperature inside the high-pressure vessel 3 was increased from 50 ° C. to 150 ° C. using a temperature controller. Further, the pressure of the back pressure valve Vb was set to 15 MPa, the pressure in the high-pressure vessel 3 was kept at 15 MPa, and thermal reduction treatment was performed for 30 minutes while discharging high pressure carbon dioxide corresponding to the pressure increase. After the thermal reduction treatment, the pressure of the back pressure valve Vb was gradually reduced to atmospheric pressure, the high-pressure vessel 3 was opened to the atmosphere, and the pre-treated polymer substrate was taken out from the high-pressure vessel 3.

(Electroless plating process)
Next, an electroless plating process is performed in which the polymer substrate pretreated as described above is subjected to electroless plating. Thereby, an electroless plating film can be formed on the polymer substrate. In this example, an electroless plating treatment was performed in which the pretreated polymer substrate was immersed in an electroless plating solution containing alcohol under normal pressure. The electroless plating solution was prepared by mixing ethanol and a nickel-phosphorus plating solution containing a metal salt of nickel sulfate, a reducing agent, and a complexing agent (Okuno Pharmaceutical Co., Ltd., Nicolon DK). Content of alcohol in electroplating solution: 50 vol%). The above electroless plating solution is put into an open container, and the pretreated polymer base material is immersed in the electroless plating solution, and an electroless plating treatment is performed at 70 to 85 ° C. under normal pressure. An electroless plating film having the following was formed.

[Example 2]
In the dilution step, an electroless plating film was formed in the same manner as in Example 1 except that the feeding time of high-pressure carbon dioxide not containing an organometallic complex was changed to 15 minutes.

[Example 3]
In the dilution step, an electroless plating film was formed in the same manner as in Example 1 except that the liquid feeding time of high-pressure carbon dioxide not containing an organometallic complex was changed to 30 minutes.

[Example 4]
In the dilution step, an electroless plating film was formed in the same manner as in Example 1 except that the feeding time of high-pressure carbon dioxide not containing an organometallic complex was changed to 45 minutes.

[Example 5]
In this example, a sheet made of nylon 6 (manufactured by Mitsubishi Plastics, Diamilon, thickness: 25 μm, width: 40 cm, length: 20 m) was used as the polymer substrate. In the permeation step, a high-pressure carbon dioxide containing no organometallic complex is used in the dilution step using a wound body 20A in which a sheet 21A is wound around a cylindrical mesh member 22 shown in FIG. 3 via an aluminum mesh separator 23. An electroless plating film was formed in the same manner as in Example 1 except that the liquid feeding time was changed to 30 minutes.

[Comparative Example 1]
After the infiltration step, without performing the dilution step, the high-pressure vessel was immediately opened to the atmosphere and the polymer substrate was taken out of the high-pressure vessel, and this was carried out except that it was subjected to thermal reduction treatment at 150 ° C. using an electric furnace under normal pressure. Although electroless plating treatment was performed in the same manner as in Example 1, the plating reaction did not proceed, and an electroless plating film could not be formed on the polymer substrate. The recovered amount of the organometallic complex recovered in the recovery tank 5 when the atmosphere was released was measured.

[Comparative Example 2]
In the infiltration process, the temperature inside the high-pressure vessel was changed to 150 ° C., and the organic metal complex was infiltrated into the polymer base material while reducing the organometallic complex. In the same manner as in Example 1, an electroless plating film was formed.

[Comparative Example 3]
After the infiltration step, an electroless plating film was formed in the same manner as in Example 1 except that the reduction step was performed immediately without performing the dilution step.

  About each polymer base material in which the electroless plating film was formed in the above Examples 1 to 5 and Comparative Examples 2 to 3, the surface of the electroless plating film was visually observed, and the electroless plating film was a polymer without defects. The case where it was formed on the entire surface of the substrate was evaluated as ◯, and the case where the electroless plating film was not formed on a part of the surface of the polymer substrate was evaluated as Δ.

  Next, using each polymer substrate on which the electroless plating film is formed, an ordinary electrolytic copper plating treatment (plating bath: copper sulfate plating bath, anode: copper electrode) is performed, and on the electroless plating film, An electrolytic plating film having a thickness of 1.0 μm was laminated. Using each polymer substrate on which this electrolytic plating film was formed, the adhesion of the plating film and the electric resistance of the plating film were measured by the following tape peeling test. Table 1 shows the results together with the recovery rates of the organometallic complexes recovered in the examples and comparative examples.

[Adhesion]
A cross-cut tape peeling test was conducted in accordance with JIS K 5600 (25 squares, 1 × 1 mm / mass) to evaluate the adhesion of the plating film. A cellophane adhesive tape (manufactured by Nichiban Co., Ltd.) was used as the peeling tape, and the tape was peeled off after the tape was adhered to the plating film with the belly of the finger. After peeling, the case where there was no peeling of the plating film out of 25 squares was evaluated as ◯, the case of partial peeling was evaluated as Δ, and the case of complete peeling was evaluated as x.

[Electric resistance]
Using a digital multimeter PC5000 tester (manufactured by Sanwa Denki Keiki Co., Ltd.), the electric resistance of the plating film was measured at room temperature.

  As shown in Table 1 above, after the organometallic complex was infiltrated into the polymer substrate at a temperature lower than the reduction temperature of the organometallic complex using a pressurized fluid, the organometallic complex was removed at a temperature lower than the reduction temperature of the organometallic complex. It can be seen that the unreduced organometallic complex can be recovered by flowing high-pressure carbon dioxide not contained in the high-pressure vessel. Moreover, it turns out that the recovery rate of the organometallic complex supplied to the high-pressure vessel becomes higher as the liquid feeding time becomes longer. And when the organometallic complex collect | recovered in the dilution process of these Examples was reused, the plating film was able to be formed without a problem similarly to the above. Therefore, it was confirmed that the recovered organometallic complex can be reused by combining an infiltration step and a dilution step below the reduction temperature of the organometallic complex.

  On the other hand, when the high pressure vessel was opened to the atmosphere immediately after the infiltration step without performing the dilution step, most of the supplied organometallic complex was recovered. This is presumably because the organometallic complex that had penetrated into the interior of the polymer substrate was detached from the polymer substrate along with the discharge of the pressurized fluid when the atmosphere was released. In addition, as in the past, when the high-pressure vessel is heated to a temperature higher than the reduction temperature of the organometallic complex in the permeation process and the organometallic complex is infiltrated into the polymer substrate while reducing the organometallic complex, the dilution process is performed. If the reduction process is performed in the high-pressure vessel immediately after the infiltration step, the pressurized fluid is discharged from the high-pressure vessel as the pressure increases during the reduction, but only the metallic substance is contained in the pressurized fluid. And no reusable organometallic complex.

  In addition, as shown in the above table, a polymer fiber substrate is obtained by performing electroless plating treatment on a polymer substrate after flowing high-pressure carbon dioxide not containing an organometallic complex in a high-pressure vessel in a dilution step. It can be seen that a plating film having excellent adhesion can be formed on both the sheet-like resin molded body and the sheet-like resin molded body. In particular, it is understood that a plating film having excellent adhesion and low electrical resistance can be formed by flowing high-pressure carbon dioxide not containing an organometallic complex so that the recovery rate is 50 to 75% by mass. For this reason, it is considered that these plating films are uniformly formed with a high anchor effect from the inside of the polymer substrate. In addition, the adhesion strength of the plating film formed in Example 5 was 15 N / cm, and it was confirmed that the plating film having an adhesion force having no practical problem was formed.

  On the other hand, when the high-pressure vessel was opened to the atmosphere immediately after the infiltration step and the reduction step was performed under normal pressure, the electroless plating film itself could not be formed. As described above, by releasing the air after the permeation step, most of the organometallic complex that has permeated the inside of the polymer base material is discharged along with the discharge of the pressurized fluid. This is probably because the amount of the organometallic complex serving as a catalyst nucleus necessary for forming the electroless plating film inside the substrate was lowered. In addition, when the reduction is performed in the permeation process or when the reduction process is performed in the high-pressure vessel immediately after the permeation process without performing the dilution process, the electroless plating film can be formed. It can be seen that the plating film peels easily from the polymer substrate. Moreover, it turns out that the electrical resistance of the formed plating film is also very high. This is because the free organometallic complex that has not penetrated into the polymer substrate is reduced in the high-pressure vessel, so that the amount of organometallic complex necessary for the plating reaction can sufficiently penetrate into the interior of the polymer substrate. This is thought to be because the metal material with reduced organometallic complex adhered to the outermost surface of the polymer substrate and the electroless plating film grew unevenly from the outermost surface with less anchor effect. .

  4 and 5 show scanning electron microscope (SEM) photographs of the cross section of the polymer substrate on which the plating film was formed in Example 3, and FIGS. 6 and 7 show the polymer substrate on which the plating film was formed in Comparative Example 2. The scanning electron microscope (SEM) photograph of the cross section of is shown. 5 and 7 are enlarged photographs of the surface portion of the polymer substrate of FIGS. 4 and 6, respectively. As shown in FIGS. 4 and 5, it can be seen that the plating film formed in Example 3 has a mixed portion in which the fiber material and the plating film are mixed on the surface of the polymer substrate. Thus, according to the present Example, since the plating film is formed from the inside of a polymer base material, it is thought that the outstanding adhesiveness is obtained. On the other hand, as shown in FIGS. 6 and 7, the plating film formed in Comparative Example 2 has a plating film formed on the surface of the polymer substrate, but the plating film is laminated on the outermost surface of the fiber material. It can only be seen that the fiber material is not formed. For this reason, it is thought that only the plating film with low adhesion could be formed. The SEM photographs in FIGS. 6 and 7 are obtained by selecting and observing a portion where the plating film covers the surface of the fiber material in order to confirm the formation state of the plating film at the interface between the plating film and the fiber material. There were many defective portions where no plating film was formed in other portions. For this reason, it is thought that the plating film of this comparative example shows high electrical resistance.

DESCRIPTION OF SYMBOLS 1 Liquid carbon dioxide cylinder 3 High pressure vessel 20 Rolling body 21 Polymer base material

Claims (3)

In a high-pressure vessel, a polymer substrate and a pressurized fluid containing an organometallic complex and high-pressure carbon dioxide are brought into contact with each other at a temperature lower than the reduction temperature of the organometallic complex, and the organometallic complex is brought into contact with the polymer substrate. Infiltrate
A high-pressure carbon dioxide containing no organometallic complex is flowed to a high-pressure vessel in which the polymer base material and the pressurized fluid are in contact with each other at a temperature lower than the reduction temperature of the organometallic complex, and the added pressure in the high-pressure vessel is increased. Dilute the pressurized fluid,
A pretreatment method for plating a polymer substrate, wherein the organometallic complex infiltrated into the polymer substrate is reduced in a state in which high-pressure carbon dioxide is contained in the high-pressure vessel.   2. The pretreatment method for plating a polymer substrate according to claim 1, wherein the polymer substrate comprises a polymer fiber substrate or a sheet-like resin molded product.   The pretreatment method for plating a polymer substrate according to claim 1 or 2, wherein the polymer substrate and the reducing agent are brought into contact with each other before the polymer substrate and the pressurized fluid are brought into contact with each other.