JP5215731B2 - Plastic surface modification method and surface modified plastic - Google Patents

Description

  The present invention relates to a surface modification method which is a pretreatment not for roughening for plating on plastic.

  There is an electroless plating method as a method for imparting metal properties (conductivity, antistatic properties, metallic luster) by forming a metal film on the surface of a nonconductive material such as plastic or ceramic. However, when plating is performed on plastic or the like, pre-treatment on the plastic is indispensable because there are problems such as insufficient adhesion of the film and uneven formation. In the pretreatment, a nucleating agent (catalyst) is used to roughen the surface (hydrophilize) and to form a metal film uniformly in order to improve adhesion to the plastic surface. The method of, is mentioned. For example, ABS (Acrylonitrile Butadiene Styrene) resin, which is often made into a product by plating with Cu or Ni, has its surface easily roughened by elution of butadiene particles by etching with chromic acid or the like. Then, by embedding a reducing metal having a strong adsorptive power such as palladium (Pd) as a nucleating agent on the roughened surface, a uniform metal film with high adhesion is formed by performing electroless plating treatment. .

  On the other hand, engineering plastics having excellent mechanical strength and heat resistance have high chemical resistance, and it is very difficult to roughen them by etching. Therefore, in recent years, a plating method using a supercritical fluid (SCF) has attracted attention. A supercritical fluid typified by supercritical carbon dioxide has both gas diffusibility and liquid solubility. For example, there is a technique (Japanese Patent No. 3571627) for forming a uniform metal film by electroless plating or the like efficiently by a small amount of plating solution due to high ion diffusibility by mixing supercritical carbon dioxide into the plating solution. It is disclosed.

Furthermore, supercritical carbon dioxide has the effect of impregnating all contaminants from the surface of the plastic due to its high permeability. Therefore, electroless plating using this property and impregnation with a nucleating agent for electroless plating are proposed. Has been. As a method therefor, a technique is disclosed in which a substrate is brought into contact with supercritical carbon dioxide mixed with a metal complex as a nucleus or a film, and the surface of the substrate is impregnated (Patent Documents 1 and 2). References 1, 2). Precisely, the metal complex is impregnated from the substrate surface to a depth of 0.1 to 0.2 μm (hereinafter referred to as the vicinity of the surface). Furthermore, a technique is disclosed in which supercritical carbon dioxide mixed with a metal complex at the time of molding of the substrate is caused to flow into the molding die to impregnate the substrate with the metal complex (Patent Document 3). Also disclosed is a technique in which a metal complex solution for forming a nucleus or a film is applied to the surface of a substrate, and the substrate is brought into contact with supercritical carbon dioxide so that the metal complex on the surface of the substrate is impregnated inside (Patent Document). 4, 5). In addition, a technique for efficiently impregnating a substrate surface by mixing a substance to be impregnated into supercritical carbon dioxide as a liquid phase containing the substance is disclosed (Patent Documents 6 and 7).
JP 2004-26986 A JP 2006-37188 A JP 2005-171222 A JP 2005-305945 A Japanese Patent No. 3931196 JP 2005-272668 A JP 2006-8945 A Teruo Hori, Satoko Okubayashi, “Development Trends of“ Supercritical Carbon Dioxide ”Technology with Expected Application Expectations”, Industrial Materials, Nikkan Kogyo Shimbun, February 2007, Vol. 55 No. 2, p. 77-82 Hiroyuki Suda, Yuko Uchimaru, Satoshi Yoda, New Energy and Industrial Technology Development Organization, 2001 Industrial Technology Research Grant Program “Development of Weather-Resistant Inorganic Membrane for Hydrogen Separation by Fine Polymer Technology and Material Composite Technology”

  However, the methods of mixing a metal complex with supercritical carbon dioxide as in Patent Documents 1 to 5 and Non-Patent Documents 1 and 2 have low impregnation efficiency because the solubility of the metal complex in supercritical carbon dioxide is low. Moreover, the process which decomposes | disassembles the metal complex impregnated on the base | substrate surface and precipitates a metal is required. This treatment method includes high temperature treatment at 120 to 200 ° C. or contact with a reducing agent, but in the case of high temperature treatment, the temperature exceeds the specification of a conventional high pressure apparatus that handles supercritical carbon dioxide, Requires capital investment. Alternatively, a dedicated high-temperature treatment device is required separately from the high-pressure device. Furthermore, such a high temperature treatment is not preferable because there is a possibility that the heat resistant resin may be modified. On the other hand, in the case of contact with the reducing agent, the metal complex impregnated to the inside of the substrate (near the surface) is not reduced only by immersing the substrate in the reducing agent solution at atmospheric pressure. In Patent Documents 6 and 7, the substance to be impregnated is not a metal but a low molecular weight polymer or nanocarbon, and the impregnation of the metal is not considered.

  The present invention has been made in view of the above-mentioned problems, and is a plating on a plastic in which a metal surface such as Pd is efficiently impregnated at a relatively low temperature (120 ° C. or lower) on the surface of the plastic used as a substrate. An object of the present invention is to provide a pre-processing method.

  In order to solve the above-mentioned problems, a plastic surface modification method according to claim 1 includes a container containing a plastic substrate, a solution obtained by dissolving a metal complex having a metal as a central atom in an organic solvent, Critical carbon dioxide is supplied, the plastic substrate is immersed in the solution, and the metal complex is impregnated in the vicinity of the surface of the plastic substrate.

  According to such a method, the metal complex can be impregnated in the vicinity of the surface of the plastic substrate efficiently by mixing the metal complex as a solution and mixing supercritical carbon dioxide with this solution.

  Furthermore, the plastic surface modification method according to claim 2 is the plastic surface modification method according to claim 1, wherein the metal complex impregnated in the vicinity of the surface of the plastic base material is reduced to reduce the metal. It is deposited on the surface of the plastic substrate and in the vicinity of the surface.

  According to such a method, the metal complex can be efficiently impregnated in the vicinity of the surface of the plastic substrate, and at the same time, the metal complex can be reduced to a metal to form a surface layer of the plastic substrate.

  According to another aspect of the plastic surface modification method of the present invention, a solution in which a metal complex having a metal as a central atom is dissolved in an organic solvent and supercritical carbon dioxide are supplied to a container that houses a plastic substrate. An impregnation step of immersing the plastic substrate in the solution to impregnate the metal complex in the vicinity of the surface of the plastic substrate, and reducing the metal complex impregnated in the vicinity of the surface of the plastic substrate. A reduction step of depositing the metal on the surface of the plastic substrate and in the vicinity of the surface in this order, and the impregnation step is performed at a temperature at which the metal complex is not reduced or at a very low rate of reduction. The reduction step is performed by raising the temperature from the temperature in the impregnation step to a temperature at which the metal complex is reduced.

  Thus, the metal complex can be sufficiently impregnated in the vicinity of the surface of the plastic substrate by first mixing the metal complex with the supercritical carbon dioxide as a solution without being reduced.

  The plastic surface modification method according to claim 4 is the plastic surface modification method according to claim 2 or 3, wherein the organic solvent is a substance that reduces the metal complex. To do. The plastic surface modification method according to claim 5 is the plastic surface modification method according to claim 2 or 3, wherein a substance for reducing the metal complex is added to the solution. Features.

  By setting it as such a solution, a metal can be deposited from a metal complex at comparatively low temperature.

  According to another aspect of the plastic surface modification method of the present invention, a solution in which a metal complex having a metal as a central atom is dissolved in an organic solvent and supercritical carbon dioxide are supplied to a container containing a plastic substrate. An impregnation step of immersing the plastic substrate in the solution to impregnate the metal complex in the vicinity of the surface of the plastic substrate, and reducing the metal complex impregnated in the vicinity of the surface of the plastic substrate. A reduction step of precipitating the metal on the surface of the plastic substrate and in the vicinity of the surface in this order, and the organic solvent is a substance that does not reduce or reduces the metal complex, and reduces the reduction The step is characterized in that a substance that reduces the metal complex is added to the solution.

  Thus, the metal complex can be sufficiently impregnated in the vicinity of the surface of the plastic substrate by first mixing the supercritical carbon dioxide in a state where the metal complex is not reduced but dissolved in the solution. Moreover, a metal can be deposited from a metal complex at a relatively low temperature.

  The plastic surface modification method according to claim 7 is the plastic surface modification method according to any one of claims 1 to 6, wherein the metal is made of Cu, Ni, Pd. It is selected from these.

  By using such a metal complex, it is possible to embed an excellent metal as a nucleating agent for plating or a plating film in a plastic substrate.

  The plastic surface modification method according to claim 8 is the plastic surface modification method according to any one of claims 1 to 6, wherein the metal complex is hexafluoroacetylacetonato palladium, It is selected from the group consisting of palladium trifluoroacetylacetonate and acetylacetonatopalladium.

  By using such a metal complex, palladium having excellent characteristics as a nucleating agent for plating can be embedded in a plastic substrate.

  The plastic surface modification method according to claim 9 is the plastic surface modification method according to any one of claims 1 to 8, wherein the plastic substrate is made of a polyimide resin or a liquid crystal polymer. It is characterized by being. The plastic according to claim 10 is a plastic substrate having a metal layer formed on the surface thereof by the plastic surface modification method according to claim 9.

  By using such a material as a substrate, a metal film can be uniformly formed on a substrate that is difficult to roughen the surface.

  According to the plastic surface modification method according to claim 1 and claim 2, the plastic base material in which the metal or metal complex is embedded in the vicinity of the surface by a single treatment and using a small amount of the metal complex. Can be obtained.

  According to the plastic surface modification method of the third aspect, the metal can be embedded in the plastic substrate surface vicinity more efficiently.

  According to the plastic surface modification method of claims 4 and 5, the treatment temperature can be made relatively low, and the plastic substrate is not denatured. Furthermore, according to the plastic surface modification method of the sixth aspect, it is possible to embed metal in the vicinity of the plastic substrate surface more efficiently and at a relatively low temperature.

  According to the plastic surface modification method of the seventh aspect, it is possible to obtain a plastic in which Pd serving as a nucleating agent is embedded, or a plastic in which a Cu or Ni film suitable for a plating material is formed. According to the plastic surface modification method of the eighth aspect, Pd serving as a nucleating agent is embedded even in the vicinity of the surface, and an excellent surface modification treatment can be performed as a pretreatment for plating.

  According to the plastic surface modification method according to the ninth and tenth aspects, a polyimide or a liquid crystal polymer with a metal film formed, which was difficult with the conventional method, can be obtained.

The plastic surface modification method according to the present invention will be described below.
FIG. 1 is a schematic view of a high-pressure processing apparatus for performing plastic surface modification processing according to an embodiment of the present invention, and FIG. 2 is a flowchart showing an example of plastic surface modification processing according to the present invention. Hereinafter, each element in the plastic surface modification treatment according to the present invention will be described.

〔Base material〕
The substrate 1 is formed by molding a plastic (synthetic resin) used for general industrial products. The plastic used must have solvent resistance. Specifically, it is a thermoplastic resin such as ABS resin, a thermosetting resin such as polyurethane, and a polyacetal (POM) classified as an engineering plastic. , Polyamide (PA), modified polyphenylene ether (m-PPE), polybutylene terephthalate (PBT), polysulfone (PSF), polyethersulfone (PES), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyimide ( PI), polyetherimide (PEI), liquid crystal polymer (LCP) and the like. In particular, it is preferable to apply polyimide, which is difficult to perform surface modification by a conventional method. Moreover, the base material 1 is processed and shape | molded by a well-known method, The shape is not specifically limited, For example, a film form, a granular form, and a fiber form may be sufficient.

[Metal complex]
It is preferable that the metal complex has, as a central atom, Pd, Cu, Ni, or the like, a nucleating agent for plating or a metal ion that becomes a plating film. Specific examples of the Pd complex include hexafluoroacetylacetonatopalladium, palladium trifluoroacetylacetonato, and acetylacetonatopalladium. In particular, hexafluoroacetylacetonato having good solubility in organic solvents described later. Palladium is preferred. Examples of the Cu complex include trifluoroacetylacetonato copper, hexafluoroacetylacetonato copper, acetylacetonato copper, and Ni complex includes hexafluoroacetylacetonato nickel. From these metal complexes, a metal complex to be used as a nucleating agent for plating or a plating film is applied. Moreover, although the density | concentration at the time of making it melt | dissolve in the organic solvent of a postscript is not specifically limited, 0.1-1 mass% (concentration in a solution) is preferable from the point of efficiency and cost.

[Organic solvent]
Examples of the organic solvent include N-methyl-2-pyrrolidinone (NMP), dimethylformamide, dimethyl sulfoxide, acetonitrile and the like. In addition, since alcohols such as ethanol and isopropanol (IPA) have the action of reducing the central metal ions of the metal complex, these may be used as organic solvents, or organic solvents having a low reducing power such as NMP as a reducing agent. You may mix and use. The type of the organic solvent is selected depending on whether the substrate 1 has solvent resistance to the organic solvent or compatibility such as an impregnation promoting effect on the substrate 1. For example, when the substrate 1 is made of polyimide, NMP having an impregnation promoting effect is preferable. In addition, when adding a reducing agent to the solution 2 in the reduction | restoration process mentioned later, the density | concentration fall of the metal complex by addition of a reducing agent is calculated, and the initial solution 2 is prepared.

[High pressure processing equipment]
As shown in FIG. 1, a high-pressure treatment apparatus for performing a surface modification treatment of plastic according to an embodiment of the present invention includes a carbon dioxide storage tank 4 and a pressure pump 5 for supplying supercritical carbon dioxide, and a surface inside. A pressure vessel 6 that can be subjected to a reforming process and is capable of high pressure treatment, and a constant temperature bath 7 as a treatment temperature adjusting means that incorporates the pressure vessel 6 are provided. Further, a high pressure valve 81 is provided upstream of the pressure vessel 6 and a pressure reducing valve 82 is provided downstream to adjust the pressure inside the pressure vessel 6. Furthermore, a recovery means (not shown) for discharging the solution 2 after the reduction reaction is provided at the bottom of the pressure vessel 6. Note that it is preferable to use the high pressure valve 81 and the pressure reducing valve 82 as pressure regulating valves because, for example, when a reducing agent is added during processing, pressure fluctuation does not occur. Any of these can use a known apparatus.

  The pressure vessel 6 has a volume capable of accommodating the base material 1 and can handle the processing temperature and the processing pressure, and the shape and material thereof are not limited as long as the material of the inner wall is resistant to an organic solvent. However, if it is too large with respect to the base material 1, a large amount of solution 2, that is, a metal complex is required, and the cost is high. Therefore, it is preferable that the pressure vessel 6 has an internal shape and volume adapted to the base material 1. For example, if the base material 1 is plate-shaped, the pressure vessel 6 is a flat container having a large bottom area. If the base material 1 is a film shape, the pressure vessel 6 is cylindrical, and the base material 1 is rolled. It is preferable to devise a method for reducing the amount of the solution 2 by storing the core material inside the wire. The inner wall of the pressure vessel 6 is preferably made of a material that does not adsorb metal deposited from the solution 2. Further, a stirring means (not shown) may be provided in the pressure vessel 6.

〔Processing method〕
Next, a processing procedure for surface modification of plastic according to an embodiment of the present invention will be described.
(Impregnation process)
First, the metal complex is dissolved in an organic solvent to prepare solution 2 (step S11). The base material 1 is stored in the pressure vessel 6, and the solution 2 is injected so that the surface of the base material 1 is completely immersed (step S12). The pressure vessel 6 is sealed and further stored in a thermostatic chamber 7. At this time, the thermostat 7 is set so that the temperature (T) in the pressure vessel 6 (solution 2) exceeds 31.1 ° C., which is the critical temperature (Tc) of carbon dioxide. However, when the metal complex is reduced by heat, when the organic solvent of the solution 2 has a reducing action on the metal complex, or when a reducing agent is included, the critical temperature is exceeded and the reduction reaction proceeds. It is preferable that the reduction reaction rate is adjusted to a very low temperature. This slow reduction reaction rate is a rate at which the reduction reaction is not completed (all the metal complexes are reduced) before the solution 2 (metal complex) is sufficiently impregnated in the vicinity of the surface of the substrate 1. To do. Although depending on the components of the solution 2, in the case of an organic solvent having a reducing action, specifically, 40 to 60 ° C. is preferable. Note that the temperature of the solution 2 is set so as not to denature the substrate 1 throughout the entire process regardless of the presence or absence of the reducing action. Next, the high pressure valve 81 is opened, supercritical carbon dioxide (scCO ₂ ) is supplied to the pressure vessel 6 by the pressure pump 5, and the high pressure valve 81 is closed (step S13).

  In the present invention, it is not necessary to completely mix the solution 2 in the pressure vessel 6 and the supercritical carbon dioxide, and the liquid phase, that is, the solution, even if it is separated into two phases (liquid phase and gas phase). 2 is mixed with a sufficient amount of supercritical carbon dioxide to impregnate the metal complex into the vicinity of the surface of the substrate 1. Specifically, a sufficient amount of supercritical carbon dioxide is mixed in the solution 2 in a state where the pressure inside the pressure vessel 6 is 72.9 atm, which is the critical pressure of carbon dioxide. Alternatively, the supercritical carbon dioxide may be supplied to the pressure vessel 6 before the solution 2 is injected.

(Reduction process)
When supercritical carbon dioxide is supplied to the pressure vessel 6, the temperature is raised to a temperature at which the metal complex in the solution 2 is reduced (T _Red ) or higher (step S14). Alternatively, a reducing agent is added to the solution 2 (reducing agent supply path is not shown). Step S14 may be executed in parallel with step S13, and is preferably executed after completion of step S13 (supercritical carbon dioxide supply completion), and more preferably executed after a predetermined time. It is. By setting the predetermined time, the metal complex in the solution 2 can be sufficiently impregnated into the vicinity of the surface of the substrate 1. The predetermined time before the reduction step (step S14) is not particularly limited, and may be set as appropriate depending on the material and shape of the substrate 1, the composition of the solution 2, and the like. When step S14 is executed simultaneously with step S13 and immediately after completion of step S13, the reduction reaction rate is adjusted not to be too high by adjusting the temperature after the temperature rise, the temperature rise rate, the concentration of the reducing agent, etc. It is preferable to do. In particular, when step S14 is executed before step S13 is completed, the metal is prevented from precipitating before the supercritical carbon dioxide is mixed into the solution 2. By adjusting the reduction reaction rate in this way, the metal complex is prevented from being reduced before the solution 2 is impregnated in the vicinity of the surface of the substrate 1. Further, the reduction reaction time is not particularly limited, and may be appropriately set depending on the composition (concentration), temperature, etc. of the solution 2, and both temperature increase and addition of a reducing agent may be performed.

  In addition, when the base material 1 is immersed in the solution 2 (step S12), the degree of the reducing action of the solution 2 on the metal complex of the organic solvent or the reducing agent and the temperature of the solution 2 are relatively slow. If supercritical carbon dioxide is promptly supplied to the pressure vessel 6 (step S13) and the temperature and pressure of the pressure vessel 6 are maintained for a predetermined time, the substrate 1 is impregnated with the metal complex. Reduction of the metal complex proceeds simultaneously. That is, the reduction process (step S14) is automatically performed without adding work. In this case, if the temperature-controlled solution 2 is injected into the pressure vessel 6, the thermostatic chamber 7 can be formed of a heat insulating material without a temperature adjusting function and only have a heat retaining function.

  When the reduction reaction is completed, the pressure reducing valve 82 is opened to release the pressure inside the pressure vessel 6 (step S15). When the inside of the pressure vessel 6 is maintained at a temperature exceeding the critical temperature and the pressure is reduced to less than the critical pressure, the carbon dioxide becomes a gas from the supercritical state, and the supercritical carbon dioxide mixed in the solution 2 is also reduced. It is separated from the liquid after the reaction (a mixture of the organic solvent and metal particles deposited without impregnating the substrate 1) and exhausted to the outside through the pressure reducing valve 82. Then, the liquid is discharged from the pressure vessel 6 by a collecting means (not shown), and the substrate 1 is taken out. Alternatively, after the liquid is discharged from the pressure vessel 6, supercritical carbon dioxide is supplied again to replace the liquid (organic solvent) impregnated in the substrate 1. By the above method, a metal can be deposited on the surface of the base material 1 and in the vicinity of the surface. Note that the reduction process (step S14) may not be performed, and the treatment may be completed by reducing the pressure in the state of the metal complex. Further, electroless plating may be performed on the substrate 1 using this metal or metal complex as a nucleating agent to further form a film.

  Although the best mode for carrying out the present invention has been described above, examples in which the effects of the present invention have been confirmed will be specifically described in comparison with comparative examples that do not satisfy the requirements of the present invention. . In addition, this invention is not limited to this Example.

(Sample preparation)
A 0.3 mm thick film made of polyimide was cut into a 10 mm square to form a substrate. Further, hexafluoroacetylacetonato palladium as a metal complex was dissolved in a solvent shown in Table 1 at a mass ratio shown in Table 1 to prepare a solution. The above-mentioned base material and 2 to 5 ml of the solution were placed in a 5 ml capacity pressure vessel, and the pressure vessel was sealed. And the temperature inside the pressure vessel (temperature of the solution) was adjusted to the temperature shown in the treatment condition 1 of Table 1. Next, carbon dioxide was injected into the pressure vessel from the outside so that the pressure became 15 MPa. After the pressure reached 15 MPa, the pressure and temperature were maintained for the time indicated in treatment condition 1 in Table 1.

  In Examples 1 to 7, after elapse of the time shown in the treatment condition 1, the pressure vessel was reduced to normal pressure and the base material was taken out to be used as test materials. On the other hand, Examples 8 to 10 were adjusted to the temperature shown in the treatment condition 2 of Table 1 while maintaining the pressure after the lapse of time. In Examples 11 and 12, ethanol as a reducing agent was added in substantially the same amount as the original solution. Furthermore, in Example 13, both the addition of ethanol as a reducing agent and the temperature increase to the temperature shown in the treatment condition 2 of Table 1 were performed. Note that the pressure in the pressure vessel was maintained at 15 MPa by the pressure regulating valve during the transition to the treatment condition 2. And after the time shown in the processing condition 2 of Table 1, the base material was taken out similarly to Examples 1-7.

  As a comparative example, the same base material as in the example was placed in a container together with a solution having the composition shown in Table 1, and adjusted so as to have a temperature shown in treatment condition 1 in Table 1. However, carbon dioxide was not injected, and the temperature was maintained at normal pressure for the time indicated in treatment condition 1 of Table 1. In Comparative Example 15, the temperature shown in the processing condition 2 in Table 1 was adjusted after the time shown in the processing condition 1 had elapsed.

  Ni-P electroless plating was performed on the obtained specimen. The test material taken out from the processing container was immersed in an electroless Ni—P plating solution made of nickel sulfate, sodium pyrophosphate, and glycolic acid, and subjected to electroless plating at 90 ° C. for 20 minutes.

(Evaluation method)
The evaluation was made by visually observing the presence or absence of plating on the surface of the specimen after Ni-P electroless plating and the presence or absence of peeling of the specimen by bending the specimen. If the Ni plating film was uniformly formed on the surface of the test material and the Ni plating film was not peeled off, it was evaluated as “Good” as good. In addition, the test material that Ni plating film partly peeled off but remained uniformly was designated as “Δ”. On the other hand, the Ni plating film was not formed uniformly, or the test material from which the Ni plating film was easily peeled off was evaluated as “x”.

  In Examples 1 and 2 processed at 40 ° C., a uniform Ni plating film could be formed although a part was peeled off. This is because the action as a nucleating agent was small because Pd embedded in polyimide completed the treatment in a complex state. On the other hand, in Examples 3 to 5 treated at 80 ° C., the Pd embedded in a complex state was reduced, so that it sufficiently acts as a nucleating agent in Ni—P electroless plating, and Ni plating that does not peel evenly A film could be formed, and it was confirmed that Pd was embedded to the inside of the vicinity of the surface of polyimide as a base material. However, in Example 6 having a Pd complex concentration of 5% by mass, a Pd film was formed on the surface of the polyimide so that a metallic luster not found in Examples 3 to 5 was observed at the completion of the treatment (before Ni-P electroless plating). However, since Pd that was not embedded in the polyimide was present, the Ni plating film was partly peeled off. Further, in Example 8 where the temperature was raised from 40 ° C. to 80 ° C. after 1 hour had passed, the Pd complex was sufficiently impregnated in the polyimide and then reduced, so that a particularly good Ni plating film could be formed. .

  In Examples 7 and 9 in which ethanol was added as a reducing agent to the solution, a Ni plating film that was uniform and not peeled off could be formed. In particular, it was confirmed in Example 7 that was treated consistently at 40 ° C. that Pd was embedded even in the vicinity of the polyimide surface even at a treatment temperature of 40 ° C. However, in Example 10 having a Pd complex concentration of 5 mass%, similar to Example 6, a metallic luster due to Pd was observed at the completion of the treatment, but a part of the Ni plating film was peeled off.

  In Example 11 in which ethanol was added to the solution after one hour had elapsed, the Pd complex was sufficiently impregnated in the polyimide and then reduced, so that a particularly good Ni plating film could be formed. However, in Examples 12 and 13 having a Pd complex concentration of 5% by mass, similar to Examples 6 and 10, a metallic luster due to Pd was recognized at the completion of the treatment, but a part of the Ni plating film was peeled off. .

  In contrast to these examples, Comparative Examples 14 and 15 in which no supercritical carbon dioxide was supplied were the same Ni—P electroless plating as in the above example, and no Ni plating film was formed. Pd could not be embedded.

It is a schematic diagram of the high-pressure processing apparatus which concerns on embodiment of this invention. It is a flowchart which shows an example of the process of surface modification of the plastic which concerns on this invention.

Explanation of symbols

1 Base material (plastic base material)
2 Solution 6 Pressure vessel (container)
scCO ₂ supercritical carbon dioxide

Claims (10)

A plastic surface modification method for forming a metal layer on the surface of a plastic substrate,
A container containing the plastic substrate is supplied with a solution obtained by dissolving a metal complex having the metal as a central atom in an organic solvent and supercritical carbon dioxide, and the plastic substrate is immersed in the solution. A plastic surface modification method comprising impregnating the metal complex in the vicinity of the surface of the plastic substrate.   2. The surface modification of plastic according to claim 1, wherein the metal complex impregnated in the vicinity of the surface of the plastic substrate is reduced, and the metal is deposited on the surface of the plastic substrate and in the vicinity of the surface. Method. A plastic surface modification method for forming a metal layer on the surface of a plastic substrate,
A container containing the plastic substrate is supplied with a solution obtained by dissolving a metal complex having the metal as a central atom in an organic solvent and supercritical carbon dioxide, and the plastic substrate is immersed in the solution. Impregnation step of impregnating the metal complex in the vicinity of the surface of the plastic substrate,
Reducing the metal complex impregnated in the vicinity of the surface of the plastic substrate, and depositing the metal on the surface of the plastic substrate and in the vicinity of the surface, in this order,
The impregnation step is performed at a temperature at which the metal complex is not reduced, or a temperature at which the rate of reduction is very low,
The plastic surface modification method, wherein the reduction step is performed by raising the temperature from the temperature in the impregnation step to a temperature at which the metal complex is reduced.   4. The plastic surface modification method according to claim 2, wherein the organic solvent is a substance that reduces the metal complex.   4. The plastic surface modification method according to claim 2, wherein a substance for reducing the metal complex is added to the solution. A plastic surface modification method for forming a metal layer on the surface of a plastic substrate,
A container containing the plastic substrate is supplied with a solution obtained by dissolving a metal complex having the metal as a central atom in an organic solvent and supercritical carbon dioxide, and the plastic substrate is immersed in the solution. Impregnation step of impregnating the metal complex in the vicinity of the surface of the plastic substrate,
Reducing the metal complex impregnated in the vicinity of the surface of the plastic substrate, and depositing the metal on the surface of the plastic substrate and in the vicinity of the surface, in this order,
The organic solvent is a substance that does not reduce or reduces the metal complex,
In the reducing step, a plastic surface modification method, wherein a substance that reduces the metal complex is added to the solution.   The plastic surface modification method according to any one of claims 1 to 6, wherein the metal is selected from the group consisting of Cu, Ni, and Pd.   7. The metal complex according to claim 1, wherein the metal complex is selected from the group consisting of hexafluoroacetylacetonatopalladium, palladium trifluoroacetylacetonato, and acetylacetonatopalladium. 8. Plastic surface modification method.   9. The plastic surface modification method according to claim 1, wherein the plastic substrate is a polyimide resin or a liquid crystal polymer.   A plastic substrate, wherein a metal layer is formed on the surface by the plastic surface modification method according to claim 9.

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