Plated component

Abstract

To provide a plated component having a base material with excellent gloss or transparency, and a plated component that improves the adhesion between the base material and the plating film.SOLUTION: A plated component 1 includes: a substrate 10; and a plating film 20 formed on a part of the surface of the substrate 10. The substrate 10 contains resin that is a copolymer having polycarbonate units and constituent units other than polycarbonate units.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a plated part, and more particularly to a plated part on which a plating film is selectively formed. [Background technology]

[0002] The market for molded interconnected devices (MIDs), which have three-dimensional circuits formed on three-dimensional resin molded products, is expanding, primarily for built-in antennas for smartphones. MIDs offer advantages such as reducing the number of printed circuit boards and flexible boards and the number of manufacturing processes, and various manufacturing methods have been developed. It has also been proposed to use MID technology in the manufacture of decorative plated products used in interior and exterior automotive parts (see, for example, Patent Document 1).

[0003] The laser direct structuring method (hereinafter referred to as the "LDS method") is known as a method for selectively forming plating on insulating substrates such as resin molded products without using photoresist. In the LDS method, a laser is irradiated onto the surface of a resin molded product containing a special additive (hereinafter referred to as the "LDS additive"), activating the laser-irradiated areas and forming a plating film on the activated areas (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-16073 [Patent Document 2] Patent No. 5579908 Summary of the Invention [Problem to be solved by the invention]

[0005] Polycarbonate is sometimes used as the base material for MIDs. Polycarbonate is an amorphous engineering plastic with excellent impact resistance and dimensional stability. It is also used as a highly decorative resin due to its unique gloss, and as a material for optical components such as lenses due to its high transparency.

[0006] When forming a plating film on the surface of an insulating substrate, etching with hexavalent chromium or the like may be performed as a pretreatment. In this case, polycarbonate has poor chemical resistance and becomes cloudy during etching, so a polymer alloy of polycarbonate and ABS is used instead of polycarbonate. However, using a polymer alloy with ABS can sometimes impair the gloss and transparency of polycarbonate.

[0007] Two-color molding is also used to form the parts where the plating film will be formed from ABS or similar materials, and the parts where the plating film will not be formed from polycarbonate. However, two-color molding requires two types of molds, which increases manufacturing costs. It is also difficult to form high-resolution patterns.

[0008] When using the LDS method, the LDS additives color the resin of the substrate, making it difficult to achieve high transparency. In addition, the LDS additives can sometimes impair the glossiness of the substrate.

[0009] Patent Document 1 describes the selective formation of a plating film on a polycarbonate substrate by a method different from the LDS method. Patent Document 1 also describes the conducting of a heat shock test in which a part (decoratively plated product) on which a plating film was formed was repeatedly placed in an environment of -35°C and an environment of 90°C, and the confirmation that the plating film did not peel off up to a specified number of cycles. However, no peel test was conducted to measure adhesion strength.

[0010] The present inventors have newly discovered that when a plating film is formed on a polycarbonate substrate using the method described in Patent Document 1, particularly when the plating film is formed on a transparent polycarbonate substrate, the adhesive strength between the substrate and the plating film may not be sufficiently high compared to when the plating film is formed on a substrate such as ABS.

[0011] An object of the present invention is to provide a plated part having a substrate with excellent gloss or transparency, in which the adhesion between the substrate and the plating film is improved. [Means for solving the problem]

[0012] A plated part according to one embodiment of the present invention comprises a substrate and a plating film formed on a portion of the surface of the substrate, the substrate containing a resin that is a copolymer having polycarbonate units and structural units other than polycarbonate units. [Effects of the Invention]

[0013] According to the present invention, a plated part having a substrate with excellent gloss or transparency and improved adhesion between the substrate and the plating film can be obtained. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view that schematically shows part of the configuration of a plated component according to one embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing the plating region. [Figure 3] FIG. 3 is an enlarged cross-sectional view showing the plating region. [Figure 4] FIG. 4 is a diagram for explaining the "thickness direction" of the substrate. [Figure 5] FIG. 5 is a diagram for explaining the "thickness direction" of the substrate. [Figure 6] FIG. 6 is a flow diagram of an example of a method for manufacturing a plated part. [Figure 7]FIG. 7 is a cross-sectional photomicrograph of the plated area of ​​a plated part using a non-copolymer polycarbonate substrate. [Figure 8] FIG. 8 is a cross-sectional photomicrograph of the plated area of ​​an example of a plated part using a polycarbonate copolymer substrate. [Figure 9] FIG. 9 is a cross-sectional photomicrograph of the plated area of ​​another example of a plated part using a polycarbonate copolymer substrate. [Figure 10] FIG. 10 is a cross-sectional photomicrograph of the plated area of ​​yet another example of a plated part using a polycarbonate copolymer substrate. [Figure 11] Figure 11 shows the roughness profile of the surface of a plated part using a non-copolymer polycarbonate substrate before plating. [Figure 12] FIG. 12 shows the roughness profile of the surface of a plated part using a polycarbonate copolymer substrate before plating. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated. The dimensional ratios between the components shown in each drawing do not necessarily represent the actual dimensional ratios.

[0016] [Plated parts] 1 is a cross-sectional view schematically illustrating a portion of the configuration of a plated component 1 according to one embodiment of the present invention. The plated component 1 includes a substrate 10 and a plating film 20 formed on a portion of the surface of the substrate 10. The plating film 20 is formed in a predetermined pattern on the surface of the substrate 10. The plating film 20 may be formed three-dimensionally across multiple surfaces of the substrate 10 or along the surface of a three-dimensional shape, including a spherical surface.

[0017] The substrate 10 contains a resin that is a copolymer having polycarbonate units and structural units other than polycarbonate units (hereinafter referred to as a "polycarbonate copolymer").

[0018] The polycarbonate unit is a structural unit having a structure containing a carbonate group (carbonate group). The polycarbonate unit may contain an aromatic compound between the carbonate groups, or may not contain an aromatic compound between the carbonate groups. The polycarbonate unit preferably contains an aromatic compound between the carbonate groups. The polycarbonate unit may be, for example, a structural unit derived from 2,2-bis(4-hydroxyphenyl)propane.

[0019] The polycarbonate unit may be a structural unit represented by the following general formula (I). [ka] In the formula, R 1 and R 2 each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, an arylene group having 6 to 12 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, a fluorenediyl group, an arylalkylene group having 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15 carbon atoms, -S-, -SO-, -SO2-, -O-, or -CO-. a and b each independently represent an integer of 0 to 4.

[0020] Of the structural units represented by general formula (I), those in which a and b are 0 and X is a single bond or an alkylene group having 1 to 8 carbon atoms, or those in which a and b are 0 and X is an alkylidene group having 2 to 8 carbon atoms, particularly an isopropylidene group, are preferred.

[0021] The polycarbonate copolymer contains polycarbonate units and structural units other than the polycarbonate units. The structural units other than the polycarbonate units include, but are not limited to, structural units having a structure containing a siloxane bond or an ether bond.

[0022] The polycarbonate copolymer preferably contains polycarbonate units as a main component. Specifically, the proportion of polycarbonate units in the polycarbonate copolymer (when there are multiple types of polycarbonate units, the total proportion) is preferably 60 mol% or more. If the proportion of polycarbonate units is too low, the gloss and transparency of the polycarbonate may be impaired. The lower limit of the proportion of polycarbonate units is more preferably 70 mol%, and even more preferably 80 mol%. On the other hand, if the proportion of polycarbonate units is too high, the effect of improving adhesion to the plating film 20 may not be obtained. The upper limit of the proportion of polycarbonate units is preferably 98 mol%, more preferably 95 mol%, and even more preferably 90 mol%.

[0023] The polycarbonate copolymer is preferably a polycarbonate-polysiloxane copolymer, that is, a copolymer containing polycarbonate units and polysiloxane units.

[0024] The polysiloxane unit is a structural unit having a structure containing a siloxane bond. The polysiloxane unit may be a structural unit represented by the following general formula (II): [ka] In the formula, R 3 and R 4 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms.

[0025] Among the structural units represented by general formula (II), R 3 and R 4 are preferably methyl groups.

[0026] The polycarbonate copolymer may be a block copolymer having a block made up of constitutional units represented by general formula (I) and a block made up of constitutional units represented by general formula (II).

[0027] The substrate 10 may be composed solely of the polycarbonate copolymer described above, or may contain fillers, colorants, and other general-purpose additives. The amount of polycarbonate copolymer in the substrate 10 is, for example, 20 to 100% by weight, and preferably 50 to 100% by weight. When the substrate 10 is to be transparent, it is preferable that the substrate 10 does not contain colorants such as carbon or colored fillers.

[0028] 1, the surface of the substrate 10 includes a plated region 10a where a plating film 20 is formed and a non-plated region 10b where no plating film 20 is formed. The surface roughness Ra of the plated region 10a is preferably larger than the surface roughness Ra of the non-plated region 10b. Increasing the surface roughness Ra of the plated region 10a can increase the adhesive strength with the plating film 20 formed thereon.

[0029] The surface roughness (arithmetic mean roughness; the same applies below) Ra of the plating region 10a is preferably 1.0 μm or more. The lower limit of the surface roughness Ra of the plating region 10a is more preferably 2.0 μm, and even more preferably 3.0 μm. The upper limit of the surface roughness Ra of the plating region 10a is, for example, 8.0 μm, preferably 6.0 μm, and even more preferably 5.0 μm.

[0030] The surface roughness Ra of the plating region 10a can be measured, for example, with a laser microscope after removing the plating film 20 with a chemical. The surface roughness Ra of the plating region 10a can also be determined by observing a cross section of the portion where the plating film 20 is formed and calculating the arithmetic mean roughness of a profile extracted from the interface between the substrate 10 and the plating film 20.

[0031] The surface roughness (arithmetic mean roughness; the same applies below) Ra of the non-plated region 10b is not particularly limited, but may be, for example, less than 1.0 μm. The surface roughness Ra of the non-plated region 10b may be 0.5 μm or less, or may be 0.2 μm or less.

[0032] The surface roughness Ra of the non-plated region 10b can be measured, for example, by a laser microscope, in the same manner as the surface roughness Ra of the plated region 10a. The surface roughness irregularities are preferably fine irregularities.

[0033] 2 and 3 are enlarged cross-sectional views of the plating region 10a. In a cross section of the substrate 10 cut along a plane including the normal direction of the substrate 10, the plating region 10a preferably has a cross-sectional shape including flat portions 10a1 having a shape that follows the surface shape of the substrate 10 and recessed portions 10a2 recessed from the flat portions 10a1 toward the interior of the substrate 10. By forming such a cross section in which the flat portions 10a1 and the recessed portions 10a2 are periodically arranged, the adhesion between the substrate 10 and the plating film 20 can be further improved.

[0034] The proportion of the flat portion 10a1 in the plating region 10a is preferably 10 to 90%. The lower limit of the proportion of the flat portion 10a1 is preferably 20%, more preferably 30%, and even more preferably 40%. The upper limit of the proportion of the flat portion 10a1 is preferably 80%, more preferably 70%, and even more preferably 60%.

[0035] Specifically, the proportion of the flat portion 10a1 in the plating region 10a is determined as follows: A cross-sectional micrograph is taken so that the width W of the field of view is 200 μm or more. The interface (boundary) between the plating film 20 and the substrate 10 is extracted from the cross-sectional micrograph. A line along the surface (contour) of the substrate 10 is translated in the thickness direction of the substrate 10 (a direction perpendicular to the width direction of the cross-sectional micrograph), and the line at which the overlap with the boundary between the plating film 20 and the substrate 10 (hereinafter simply referred to as the "boundary") is greatest is determined as the reference line BL. Note that because the reference line BL is a line along the surface (contour) of the substrate 10, it will be curved if the surface of the substrate 10 is curved. The sum of the lengths of the overlapping portions of the reference line BL and the boundary within the observation field of view (in the example of Figure 3, la1 + la2 + la3 + la4) divided by the width W of the field of view is defined as the "proportion of the flat portion 10a1 in the plating region 10a."

[0036] The average length of the flat portion 10a1 ((la1+la2+la3+la4) / 4 in the example of FIG. 3) is preferably 10 to 100 μm.

[0037] The proportion of recesses 10a2 in the plating region 10a is preferably 10 to 90%. The lower limit of the proportion of recesses 10a2 is preferably 20%, more preferably 30%, and even more preferably 40%. The upper limit of the proportion of recesses 10a2 is preferably 80%, more preferably 70%, and even more preferably 60%.

[0038] The proportion of recesses 10a2 in the plating region 10a is the sum of the lengths of the regions in the cross-sectional micrograph where the boundary line is closer to the center of the substrate 10 than the reference line BL (in the example of Figure 3, lb1 + lb2 + lb3 + lb4) divided by the width W of the field of view.

[0039] The average length of the recesses 10a2 (in the example of FIG. 3, (lb1+lb2+lb3+lb4) / 4) is preferably 20 to 100 μm.

[0040] The average depth of the recesses 10a2 is preferably 3 to 50 μm. The average depth of the recesses 10a2 is determined by dividing the total area of ​​the regions where the boundary lines are located closer to the center of the substrate 10 than the reference line BL by the total length of the regions where the boundary lines are located closer to the center of the substrate 10 than the reference line BL (lb1+lb2+lb3+lb4 in the example of FIG. 3).

[0041] The plated component 1 may have a transparent substrate 10. More specifically, the non-plated region 10b of the substrate 10 may have a total visible light transmittance of 50% or more when irradiated with light in the thickness direction. Here, the "thickness direction" refers to the direction including the smallest dimension t of the target region TA when measuring the total visible light transmittance (see FIG. 4). However, if the substrate 10 is an optical component such as a lens, the dimension t in the direction in which light is expected to be irradiated when the component is in use is defined as the thickness, and the direction parallel to this direction is defined as the thickness direction (see FIG. 5). When the substrate 10 is transparent, the total visible light transmittance is more preferably 60% or more, and even more preferably 70% or more.

[0042] Alternatively, the plated component 1 may have a glossy black (jet black) color tone called piano black in the non-plated area 10b of the substrate 10. Piano black has a glossiness and a L * a * b * For example, piano black is preferably a black having a 60-degree specular gloss of 90 or more and a L * a * b * In the color system, L * is 8 or less, a * is -0.5 to 0, b * is -1.5 to 0, and more preferably, the 60-degree specular gloss is 90 or more, and L * a * b * In the color system, L * is less than or equal to 1, a * is -0.2 to 0, b * is between -1 and 0.

[0043] The plating film 20 is formed on the plating region 10a of the substrate 10. Although not shown in FIG. 1, the plating film 20 may be composed of multiple layers. Specifically, the plating film 20 may include an electroless plating film formed on the substrate 10 and an electrolytic plating film formed on the electroless plating film. The electrolytic plating film may also be composed of multiple types of electrolytic plating films. The electroless plating film is not particularly limited, but examples include electroless nickel phosphorus plating film and electroless copper plating film, with electroless nickel phosphorus plating film being preferred. The electrolytic plating film is not particularly limited, but examples include electrolytic copper plating film and electrolytic nickel plating film.

[0044] The thickness of the plating film 20 (if the plating film 20 is composed of multiple layers, the total thickness of the layers; the same applies below) is not particularly limited, but is, for example, 0.5 to 60 μm. The lower limit of the thickness of the plating film 20 is preferably 1.0 μm. The upper limit of the thickness of the plating film 20 is preferably 40 μm, and more preferably 35 μm.

[0045] The adhesion strength between the substrate 10 and the plating film 20 is preferably 1.0 N / cm or more from the viewpoint of ensuring adhesion between the substrate 10 and the plating film 20. The lower limit of the adhesion strength is preferably 2.0 N / cm, and more preferably 5.0 N / cm. The upper limit of the adhesion strength is not particularly limited as long as adhesion between the substrate 10 and the plating film 20 can be ensured, but is, for example, 40 N / cm, and preferably 30 N / cm. The adhesion strength can be measured by a peel test, for example, by the method described in the Examples.

[0046] 1, the plated part 1 may further include a catalytic activity interference layer containing a polymer having an amide group and a sulfur-containing group on the non-plated region 10b of the substrate 10. Details of the catalytic activity interference layer will be described later.

[0047] [Method of manufacturing plated parts] Next, an example of a method for manufacturing the plated part 1 will be described. FIG. 6 is a flow diagram of an example of a method for manufacturing the plated part 1. This manufacturing method includes a step of forming a catalytic activity impediment layer on a substrate (step S1), a step of irradiating a part of the surface of the substrate on which the catalytic activity impediment layer has been formed with a laser beam (step S2), a step of applying an electroless plating catalyst to the substrate irradiated with the laser beam (step S3), and a step of contacting the substrate to which the electroless plating catalyst has been applied with an electroless plating solution (step S4). Each step will be described in detail below.

[0048] First, a catalytic activity-blocking layer is formed on the surface of the substrate (step S1). The "substrate" here is a member corresponding to the substrate 10 of the plated part 1 (FIG. 1) to be manufactured. Therefore, this "substrate" contains a resin that is a copolymer (polycarbonate copolymer) having polycarbonate units and structural units other than polycarbonate units. Hereinafter, this "substrate" will be referred to as the "raw substrate" to distinguish it from the substrate 10 of the finished product (plated part 1). The raw substrate is, for example, a molded product of a polycarbonate copolymer.

[0049] A portion of the surface of the base material is roughened by a laser beam irradiation step (step S2) described below. The portion roughened in this step (laser beam irradiated portion) becomes the plated region 10a in Fig. 1, and the portion not roughened (laser beam non-irradiated portion) becomes the non-plated region 10b in Fig. 1. Therefore, the surface roughness Ra of the non-plated region 10b of the plated part 1 to be manufactured can be adjusted by the surface roughness Ra of the base material.

[0050] The catalytic activity inhibitor layer is a layer containing a compound (hereinafter referred to as a "catalytic activity inhibitor") that reduces the function of the electroless plating catalyst used in step S3. The catalytic activity inhibitor may be, for example, a compound having a functional group that adsorbs the electroless plating catalyst. Examples of functional groups that adsorb the plating catalyst include, but are not limited to, amide groups, amino groups, ether bonds, and sulfur-containing groups. Examples of sulfur-containing groups include sulfide groups, dithiocarbamate groups, and thiocyanate groups. The catalytic activity inhibitor may be a compound having two or more of these functional groups.

[0051] The catalyst activity inhibitor is preferably a polymer having an amide group and a sulfur-containing group, and more preferably a polymer having an amide group and a dithiocarbamate group in a side chain. The catalyst deactivator is preferably a dendritic polymer such as a dendrimer or a hyperbranched polymer.

[0052] As the dendritic polymer, for example, a hyperbranched polymer disclosed in WO 2017 / 154470 or WO 2018 / 131492, which is represented by the following formula (1) and has a weight-average molecular weight of 1,000 to 1,000,000, is preferred.

[0053] [ka] In formula (1), A 1 is a group containing an aromatic ring, and A 2 is a group containing an amide group, and A 3 is a sulfur-containing group, and R 0 represents hydrogen or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, m1 is 0.4 to 11, and n1 is 5 to 3,500.

[0054] The catalytic activity-hindering layer is preferably thin so as not to affect the properties of the base substrate. On the other hand, from the viewpoint of hindering catalytic activity, it is better not to be too thin. The thickness of the catalytic activity-hindering layer is, for example, 10 to 5000 nm. The lower limit of the thickness of the catalytic activity-hindering layer is preferably 20 nm, more preferably 30 nm. The upper limit of the thickness of the catalytic activity-hindering layer is preferably 500 nm, more preferably 200 nm. The catalytic activity-hindering layer is preferably formed at least in the region of the surface of the base material to which the electroless plating catalyst is applied in the step of applying the electroless plating catalyst (step S3) described below, and more preferably formed on the entire surface of the base material. The catalytic activity-hindering layer may be removed, for example, after the electroless plating step (step S4).

[0055] The method for forming a catalytic activity-interfering layer on the surface of a base substrate is not particularly limited. For example, a treatment liquid may be prepared by dissolving or dispersing a catalytic activity-interfering agent in a solvent or dispersion medium, and the treatment liquid may be brought into contact with the base substrate to form a catalytic activity-interfering layer. The treatment liquid may be applied to the base substrate, or the base substrate may be immersed in the treatment liquid. Specific formation methods include dip coating, screen coating, spray coating, etc.

[0056] A laser beam is irradiated onto a portion of the surface of the base material on which the catalytic activity-preventing layer has been formed (step S2). Specifically, the laser beam is irradiated onto the surface of the base material in an area where the plating film 20 (FIG. 1) is to be formed, i.e., an area corresponding to plating area 10a. As a result, the catalytic activity-preventing layer in the area corresponding to plating area 10a is selectively removed (or the catalytic activity-preventing layer in that area is selectively modified), and that area is selectively roughened.

[0057] The laser beam is not particularly limited, but examples that can be used include infrared lasers such as YVO4 laser (λ=1064 nm), fiber laser (λ=1090 nm), CO2 laser (λ=10 μm), green laser (λ=532 nm), UV laser (λ=355 nm), excimer laser (λ=193 nm), etc. Among these, UV lasers are preferred because they can produce fine concave-convex shapes.

[0058] Next, an electroless plating catalyst is applied to the laser beam-irradiated base substrate (step S3). The electroless plating catalyst can be, for example, a metal salt with electroless catalytic activity. Examples of metal salts include salts of Pd, Pt, Cu, Ni, etc., with Pd being preferred due to its high catalytic activity. Examples of Pd salts include palladium chloride, palladium acetate, and palladium complexes, with inexpensive and stable palladium chloride being preferred.

[0059] The region irradiated with the laser beam (plating region 10a) has a larger surface area due to roughening compared to the region not irradiated with the laser beam (non-plating region 10b), and thus a larger amount of electroless plating catalyst is adsorbed. Furthermore, a catalytic activity-blocking layer remains in the region not irradiated with the laser beam (non-plating region 10b), suppressing the plating reaction in that area. This allows an electroless plating film to be selectively formed in the region irradiated with the laser beam (plating region 10a) in the next electroless plating step (step S4).

[0060] Next, the base substrate to which the electroless plating catalyst has been applied is contacted with an electroless plating solution (step S4). The electroless plating solution may be, but is not limited to, an electroless copper plating solution, an electroless copper-nickel plating solution, or an electroless nickel-phosphorus plating solution. After the electroless plating film is formed, if necessary, electroplating may be performed using the electroless plating film as a conductor to form an electrolytic plating film on the electroless plating film.

[0061] Through the above steps, a plated component 1 is manufactured in which the plating film 20 is selectively formed on the plating region 10a.

[0062] In the above example, a catalytic activity impediment layer is formed on the surface of the base substrate before the base substrate is roughened. By forming a catalytic activity impediment layer, deposition of plating in the non-plating region 10b can be further suppressed. On the other hand, as described above, the roughened portion (plating region 10a) has a larger surface area, which increases the amount of plating catalyst adsorbed. Therefore, even without forming a catalytic activity impediment layer, a contrast can be created between the plating region 10a and the non-plating region 10b. Therefore, depending on the fineness of the pattern to be formed, it is possible to manufacture plated parts without using a catalytic activity impediment layer.

[0063] [Effects of this embodiment] In the plated component 1 according to this embodiment, the substrate 10 contains a resin (polycarbonate copolymer) that is a copolymer having polycarbonate units and structural units other than polycarbonate units. Experiments have shown that the use of a polycarbonate copolymer can improve the adhesive strength between the substrate 10 and the plating film 20 compared to when a non-copolymer polycarbonate substrate is used. The reason why the use of a polycarbonate copolymer improves adhesive strength is not clear, but is presumed to be as follows.

[0064] Figure 7 is a cross-sectional micrograph of the plated region of a plated part (Comparative Example 1, described later) that uses a non-copolymer polycarbonate substrate. In plated parts that use a non-copolymer polycarbonate substrate, the plated region has a relatively flat cross-sectional shape that conforms to the surface shape of the substrate overall. Although the reason is unclear, when polycarbonate is used as the substrate, particularly when transparent polycarbonate is used as the substrate, it is more difficult to form irregularities suitable for achieving an anchoring effect with the plating film than when other engineering plastics (e.g., ABS) are used as the substrate.

[0065] 8 to 10 are cross-sectional micrographs of the plated region of a plated part using a polycarbonate copolymer substrate (Examples 1 to 3, described below). In plated parts using a polycarbonate copolymer substrate, the plated region has a cross-sectional shape that includes a flat portion that conforms to the surface shape of the substrate and a recess that is recessed from the flat portion toward the inside of the substrate. It is believed that the substrate has such a cross-sectional shape, which improves adhesion to the plating film. It is not clear why such a cross-sectional shape is obtained by using a polycarbonate copolymer as the substrate, but it is presumed to be due to the difference in reactivity to the laser beam between segments made of polycarbonate units and other segments.

[0066] Fig. 11 shows the roughness profile of the surface of a plated part (Comparative Example 1, described later) that uses a polycarbonate substrate that is not a copolymer before plating. Fig. 12 shows the roughness profile of the surface of a plated part (Example 1, described later) that uses a polycarbonate copolymer substrate before plating. In Figs. 11 and 12, height is displayed on a seven-level scale based on the maximum and minimum values ​​of the measurement data. White areas are convex regions (regions with high height or small depth), and black areas are concave regions (regions with low height or large depth).

[0067] As shown in Figure 11, in plated parts using a non-copolymer polycarbonate substrate, the plated areas are lighter than the non-plated areas. That is, in plated parts using a non-copolymer polycarbonate substrate, the plated areas (areas roughened by the laser beam) have irregularities that extend outward (upward) from the surface of the substrate. In contrast, as shown in Figure 12, in plated parts using a polycarbonate copolymer substrate, the plated areas are darker than the non-plated areas, and the plated areas (areas roughened by the laser beam) have irregularities that extend inward (downward) from the surface of the substrate.

[0068] The above describes a plated part 1 according to one embodiment of the present invention. According to this embodiment, a plated part having a substrate with excellent gloss or transparency and improved adhesion between the substrate and the plating film can be obtained.

[0069] The plated parts of this embodiment can contribute to achieving Goal 7 (Affordable and clean energy), Goal 9 (Industry, innovation and infrastructure), Goal 11 (Sustainable cities and communities), and Goal 12 (Responsible consumption and production) of the 17 Sustainable Development Goals (SDGs) established by the United Nations. [Example]

[0070] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0071] [Example 1] (a) Base material As a substrate, a polycarbonate resin (siloxane copolymer grade) Toughlon (registered trademark) AG1950 manufactured by Idemitsu Kosan Co., Ltd. was molded to prepare a plate measuring 50 mm x 80 mm x 1 mm thick.

[0072] Before plating the substrate, the surface roughness and total light transmittance were measured. The surface roughness (Ra) of the substrate was determined by calculating the arithmetic mean roughness from the line roughness profile of the surface measured over a 760 μm × 406 μm field of view using a Keyence Corporation laser microscope (VK-9700). For the calculation, line roughness profiles were extracted from three randomly selected locations parallel to the short side (406 μm) of the area measured by the microscope, i.e., perpendicular to the long side (760 μm). Each profile was subjected to noise reduction and waviness (wavelength 20 μm) correction, and the arithmetic mean roughness was calculated. The surface roughness (Ra) was calculated as the average of the arithmetic mean roughness values ​​obtained from the line roughness profiles at the three randomly selected locations. The transmittance was measured using a JASCO V-570 with a large integrating sphere (IVL-472) in the wavelength range of 380 to 780 nm using a haze value measurement program, and the total light transmittance was measured. As a result of the measurement, the surface roughness Ra of the substrate was 0.2 μm, and the total light transmittance was 85.5%.

[0073] (b) Formation of catalytically inactive layer A polymer represented by the following general formula (A) was dissolved in propylene glycol monomethyl ether to prepare a polymer solution with a polymer concentration of 1.0 wt%, and then an equal amount of isopropyl alcohol was added to prepare a polymer solution with a polymer concentration of 0.5 wt%. A substrate was immersed in the polymer solution at room temperature for 5 seconds and then dried in a dryer at 80°C for 15 minutes. This formed a catalytic activity interference layer on the surface of the substrate. The thickness of the catalytic activity interference layer was 100 nm. [ka] In formula (A), R 0is a methyl group.

[0074] (c) Laser beam irradiation A UV laser (Keyence Corporation, 3-Axis UV Laser Marker, MD-U1000C) was used to form a predetermined pattern on the substrate. The laser drawing conditions were 60% power, 300 mm / s speed, and 50 kHz frequency, with a contour shrinkage of 10 μm and a fill pitch of 10 μm.

[0075] (d) Plating (d-1) Plating pretreatment and cleaning An aqueous polyethyleneimine solution (P7-70 manufactured by Wako Pure Chemical Industries, Ltd.) was prepared. After the substrate was immersed in the aqueous polyethyleneimine solution adjusted to 40° C. for 3 minutes, the substrate was taken out of the aqueous polyethyleneimine solution and washed with water.

[0076] (d-2) Addition of electroless plating catalyst Next, the substrate was immersed for 3 minutes in a commercially available aqueous solution of palladium chloride (PdCl2) (Activator, manufactured by Okuno Chemical Industries Co., Ltd.) adjusted to 30°C, and then the substrate was taken out of the aqueous solution of palladium chloride and washed with water.

[0077] (d-3) Electroless plating The substrate was immersed for 5 minutes in an electroless nickel-phosphorus plating solution (ICP Nicorone LTN-NP, manufactured by Okuno Chemical Industries Co., Ltd., pH 6.5, phosphorus concentration 5% by weight) adjusted to 60°C, resulting in the deposition of an electroless nickel-phosphorus plating film in the area irradiated with the laser beam.

[0078] (d-4) Electroplating Next, the substrate was immersed in an electrolytic plating solution (copper sulfate plating bath) adjusted to 30°C, and the plating was conducted at a current of 2 A / dm 2 The electrolytic plating film was formed at a voltage of 1000 kJ / cm for 3 hours. The thickness of the plating film was 30 μm.

[0079] The samples prepared under the respective conditions were evaluated according to the following (A) to (D).

[0080] (A) Plating pattern In step (c), a laser beam was irradiated in a pattern of fine lines with L / S = 200 μm / 200 μm, and the plating process was carried out up to step (d-3), depositing a nickel-phosphorus plating film with a width of 200 μm to produce wiring confirmation sample 1A.

[0081] When the obtained substrate was observed under a microscope, no abnormal deposition of plating was observed in the 200 μm spaces that were not irradiated with the laser beam, and it was confirmed that fine plated wiring had been formed.

[0082] (B) Evaluation by peel test In step (c), a pattern measuring 1 cm wide and 10 cm long was irradiated onto the center of the substrate, and all plating steps up to step (d-4) were carried out. However, to prevent the plating film from breaking during the tensile test, the electroplating time was doubled and the electroplating thickness was set to 71 μm. The resulting sample was dried at 80°C for 1 hour to prepare Sample 1B for peel testing. The plating film was peeled off using a force gauge tester, and the adhesion strength was measured, resulting in a value of 25 N / cm.

[0083] (C) Measurement of surface roughness of plated area In step (c), a pattern with a width of 0.35 mm was irradiated, and the surface roughness of the irradiated area was measured in the same manner as in step (a). The surface roughness Ra was 2.80 μm.

[0084] (D) Cross-sectional observation A sample equivalent to the peel test sample was prepared, and a sample for cross-sectional observation was prepared using a Hitachi High-Tech IM4000 ion milling device. After that, the sample was observed using a scanning electron microscope (accelerating voltage 2 kV, secondary electron image (LA100), working distance (WD): 2 to 8 mm).

[0085] [Example 2] Wiring confirmation sample 2A and peel test sample 2B were prepared in the same manner as in Example 1, except that the substrate was a polycarbonate resin (siloxane copolymer grade) Toughlon (registered trademark) AG1760 manufactured by Idemitsu Kosan Co., Ltd. The surface roughness Ra of the substrate before processing was 0.1 μm, and the total light transmittance was 85.5%. Wiring confirmation sample 2A confirmed that there was no abnormal deposition in the non-plated area. The adhesion strength was 16 N / cm, and the surface roughness Ra of the plated area was 2.21 μm.

[0086] [Example 3] Wiring confirmation sample 3A and peel test sample 3B were prepared in the same manner as in Example 1, except that the substrate was a polycarbonate resin (siloxane copolymer grade) Toughlon (registered trademark) RC1760 manufactured by Idemitsu Kosan Co., Ltd. The surface roughness Ra of the substrate before processing was 0.2 μm, and the total light transmittance was 90.1%. It was confirmed from wiring confirmation sample 3A that there was no abnormal deposition in the non-plated area. The adhesion strength was 5.2 N / cm, and the surface roughness Ra of the plated area was 1.92 μm.

[0087] [Comparative Example 1] Wiring confirmation sample 4A and peel test sample 4B were prepared in the same manner as in Example 1, except that the substrate was a general-purpose polycarbonate (polycarbonate resin (natural grade) Toughlon (registered trademark) IR1700 manufactured by Idemitsu Kosan Co., Ltd.). The surface roughness Ra of the substrate before processing was 0.2 μm, and the total light transmittance was 89.9%. It was confirmed from wiring confirmation sample 4A that there was no abnormal deposition in the non-plated area. The adhesion strength was 0.8 N / cm, and the surface roughness Ra of the plated area was 0.94 μm.

[0088] Fig. 7 is a cross-sectional photograph of Comparative Example 1. Figs. 8 to 10 are cross-sectional photographs of Examples 1 to 3, respectively. In Comparative Example 1, the plating region had a relatively flat cross-sectional shape that generally followed the surface shape of the substrate, whereas in Examples 1 to 3, the plating region had a cross-sectional shape that included a flat portion that followed the surface shape of the substrate and a recess that recessed from the flat portion toward the inside of the substrate. It is believed that in the plated parts of Examples 1 to 3, the substrate having such a cross-sectional shape improved adhesion with the plating film, resulting in improved adhesion strength.

[0089] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention. [Explanation of symbols]

[0090] 1 Plated parts 10 Base material 10a Plating area 10a1 flat area 10a2 recess 10b Non-plated area 20 Plating film

Claims

1. A substrate; a plating film formed on a portion of the surface of the base material, The plated part is characterized in that the substrate contains a resin that is a copolymer having polycarbonate units and structural units other than polycarbonate units.

2. 2. The plated component according to claim 1, wherein a surface roughness Ra of a plating region, which is a region on the surface of the substrate where the plating film is formed, is greater than a surface roughness Ra of a non-plating region, which is a region where the plating film is not formed.

3. The plated part of claim 1, wherein the copolymer is a polycarbonate-polysiloxane copolymer.

4. 2. The plated part according to claim 1, wherein the proportion of the polycarbonate units in the copolymer is 60 to 98 mol %.

5. The plated part according to any one of claims 1 to 4, wherein the surface roughness Ra of the plating region, which is the region on the surface of the substrate where the plating film is formed, is 1.0 µm or more.

6. a plating region on the surface of the base material where a plating film is formed has a cross-sectional shape including a flat portion having a shape that follows the surface shape of the base material and a recessed portion recessed from the flat portion toward the inside of the base material, The plated part according to any one of claims 1 to 4, wherein the proportion of the recesses in the plated region is 10 to 90%.

7. The plated part according to any one of claims 1 to 4, wherein the substrate is transparent.

8. 5. The plated part according to claim 1, wherein a non-plated region of the substrate, which is a region where the plating film is not formed, has a total visible light transmittance of 50% or more when irradiated with light in a thickness direction.

9. The plated part according to any one of claims 1 to 4, further comprising a catalytic activity interference layer formed in a non-plating area of ​​the substrate where the plating film is not formed, the catalytic activity interference layer comprising a polymer having an amide group and a sulfur-containing group.

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