JP2017179530A - Plated product and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin plated product having high adhesion strength between a plated layer and a body to be plated, and having sufficient surface appearance even when the plated layer is thin.SOLUTION: The plated product comprises a body to be plated having a resin layer including a thermoplastic resin composition on the surface and a plated layer provided thereon. The thermoplastic resin composition includes: a graft copolymer (I) obtained by graft co-polymerizing a monomer mixture including at least an unsaturated nitrile monomer and an aromatic vinyl monomer with a rubbery polymer; and a styrene based copolymer (II) using at least the unsaturated nitrile monomer and the aromatic vinyl monomer as a constituent. The maximum height difference of irregularities on the surface of the body to be plated is 200 nm or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a plated product and a manufacturing method thereof.

In recent years, a plating process on a resin surface has been performed for the purpose of reducing the weight by converting a metal part into a resin and imparting design properties to a resin product. There are various types of resins used at this time, but ABS resins are generally used from the viewpoint of ease of plating, a feeling of rigidity (closer to a metal feeling), and price.
By the way, as a conventional plating method for resin moldings, etc., after forming irregularities on the resin molding surface by etching with a solvent such as chromic acid mixed solution, neutralization, catalyst application, electroless plating, A method of performing electroplating is employed. As described above, a chromic acid mixed solution containing chromium trioxide as a main component is used as a solvent for this etching. However, hexavalent chromium contained in this chromic acid mixture is a harmful substance, and problems such as adverse effects on the working environment and environmental effects such as drainage have been pointed out.
For example, Patent Document 1 proposes a plating method using an etching solution using permanganic acid, and Patent Document 2 proposes a plating method including an etching process by ultraviolet irradiation.
The purpose of the etching is to improve the adhesion strength between the resin and the plating layer. In other words, the surface of the resin has large irregularities with a height difference of about 500 nm due to the strong oxidizing action of the mixed chromic acid, and a plating layer is formed thereon to express physical adhesion due to the irregularities. It is.
Therefore, in order to improve the appearance (smoothness) of the plating surface, it is necessary to form a considerably thick plating layer that does not cause the unevenness on the resin. This thick plating layer greatly reduces the traceability of the surface shape of the resin molded product, and causes a time load in the process, which is disadvantageous in terms of cost.

  In recent years, attempts have been made to apply resin-plated products to parts for which metal has been used so far, and there is an increasing demand for plating minute parts. The traceability of the shape of the resin product has been required due to the minute parts, and the market strongly demands a plated product having a sufficient surface appearance even with a thin plating layer.

WO2015 / 060196 JP2015-57515A

In the technique using heavy metal as an etchant solution as shown in the publicly known literature in the prior art, the problem that the etching time is long and the process load is still high is not solved. In addition, the etching technique by ultraviolet irradiation is a proposal for application only to a specific resin, and when applied to an ABS resin or the like, the adhesion strength is not sufficient and cannot be applied.
In either case, there is a problem that a good surface appearance cannot be obtained if the thickness of the plating layer is reduced.
That is, an object of the present invention is to provide a resin plating product having a high plating layer-to-be-plated adhesion strength and having a sufficient surface appearance even when the plating layer is thin.

  As a result of intensive studies, the present inventors have made the resin surface of the object to be plated in contact with the plating layer highly smooth, specifically, by setting the level difference of the unevenness to a specific range, It is possible to form a resin-plated product with a smooth surface appearance without increasing the thickness, and also to achieve an adhesive strength that can withstand practical use. Furthermore, the adhesive strength is the content of unsaturated nitrile monomer units in the ABS resin The present invention was completed by finding that it increases when a high styrene copolymer is contained.

That is, the present invention is as follows.
[1] A plated product having a body to be plated having a resin layer containing a thermoplastic resin composition on the surface, and a plating layer provided thereon,
The thermoplastic resin composition comprises at least a graft copolymer (I) obtained by graft copolymerization of a rubber mixture with a monomer mixture containing at least an unsaturated nitrile monomer and an aromatic vinyl monomer. A styrene copolymer (II) comprising a saturated nitrile monomer and an aromatic vinyl monomer as constituent components,
The maximum value of the height difference of the unevenness of the surface of the object to be plated is 200 nm or less,
Plating product.
[2] The plated product according to [1], wherein an adhesion strength between the plated layer and the object to be plated is 5 N / cm or more by a measurement method based on JIS H8630.
[3] When the styrene copolymer (II) has a total of 100% by mass of unsaturated nitrile monomer units and aromatic vinyl monomer units, 30 to 30 unsaturated nitrile monomer units. The plated product according to [1] or [2], containing 50% by mass.
[4] The method for producing a plated product according to any one of [1] to [3], including an etching step by ultraviolet irradiation.

  ADVANTAGE OF THE INVENTION According to this invention, even if it does not make a plating layer extremely thick, the surface appearance is favorable and it can provide the resin plating product which has high adhesion strength (plating layer-resin interlayer adhesion strength).

It is a specific example of the scanning transmission electron microscope (STEM) photograph of the cross section of a plating product. It is the schematic which shows the shape of the to-be-plated body in Example 6 and Comparative Example 3. FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. However, the present invention is not limited to this, and various modifications can be made without departing from the gist thereof. Is possible.

<Substance to be plated>
The to-be-plated body which contacts the plating layer which comprises the plating product of this embodiment has the resin layer containing a thermoplastic resin composition on the surface. The surface of the object to be plated only needs to be made of a resin. For example, the entire body may be made of a resin (a composition containing a thermoplastic resin composition) or made of a material other than a resin. It may be formed from a core portion and a resin layer formed on the surface thereof.
In the present embodiment, the surface of the object to be plated (the surface of the resin layer) is extremely smooth. Specifically, the maximum value of the height difference of the unevenness is 200 nm or less. Since the unevenness is small, it is possible to give a good surface appearance without increasing the thickness of the plating layer. Conventionally, relatively large irregularities have been formed on the surface of the object to be plated by etching or the like in order to increase the adhesion strength. Therefore, a good surface appearance could not be achieved unless the plating layer was thickened. However, according to the study by the present inventors, it has been unexpectedly found that sufficient adhesion strength can be obtained even if the maximum value of the uneven height difference is 200 nm or less.
The maximum value of the height difference of the preferable unevenness is 150 nm, more preferably 100 nm, still more preferably 70 nm, and most preferably 50 nm. Since the smoother the better, there is no minimum value. However, in general, the surface has gentle irregularities of several nm.

In the present embodiment, the height difference of the unevenness is determined by using a scanning transmission electron microscope using an ultrathin section prepared by a FIB (Focused Ion Beam) method from a cross section of the plated product (cross section perpendicular to the tangent plane of the plating surface). (STEM) is obtained by arbitrarily photographing the interface between the plating layer and the resin layer with a field of view of 1.7 × 2.5 μm and measuring the height difference of the largest unevenness on the resin surface in contact with the plating layer. . In bright field observation of STEM, a region with a large atomic number is dark and a region with a small atomic number is bright. The catalyst or plating layer used for plating is a metal, and has a larger atomic number than a resin mainly composed of carbon or hydrogen. By utilizing this, the surface of the bright layer in contact with the dark contrast layer in each field of view can be regarded as the resin surface in contact with the plating layer (see FIG. 1).
In this way, the difference in height of the largest unevenness is measured for any 10 fields of view of the cross section of the plated product, and the average value of these 10 is the height difference of the unevenness on the surface of the object to be plated in this embodiment. Maximum value.

<Thermoplastic resin composition>
In this embodiment, the thermoplastic resin composition which comprises the resin layer of the to-be-plated body surface contains the graft copolymer (I) and the styrene-type copolymer (II).

(Graft copolymer (I))
The graft copolymer (I) is a graft copolymer obtained by graft copolymerizing a rubber polymer with a monomer mixture containing at least an unsaturated nitrile monomer and an aromatic vinyl monomer.
As the rubbery polymer, for example, those having a glass transition temperature (Tg) of 0 ° C. or less can be preferably used.
Specific examples of the rubbery polymer include, but are not limited to, polybutadiene, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, polyisoprene, polychloroprene, styrene-butadiene block copolymer rubber, styrene- Isoprene block copolymer rubber, conjugated diene rubber such as ethylene-propylene-diene terpolymer rubber, acrylic rubber such as polybutyl acrylate, ethylene-propylene rubber, silicon rubber, silicon-acrylic composite rubber, and their Examples thereof include hydrogenated products.
Among these, conjugated diene rubbers are preferable, and polybutadiene, styrene-butadiene copolymer rubber, and acrylonitrile-butadiene copolymer rubber are particularly preferable. Among these, polybutadiene, styrene-butadiene copolymer, styrene-butadiene block copolymer, and acrylonitrile-butadiene copolymer are preferable in order to maintain strength such as impact resistance of the plated product.

The rubbery polymer contained in the graft copolymer (I) is preferably in the form of particles, and preferably present in a finely dispersed state in the thermoplastic resin composition. The number average particle diameter is preferably 0.05 μm or more and 0.4 μm or less. The lower limit of the volume average particle diameter of the rubbery polymer is more preferably 0.07 μm, further preferably 0.10 μm, and most preferably 0.15 μm. Moreover, a preferable upper limit is 0.35 micrometer, Most preferably, it is 0.3 micrometer.
The number average particle diameter can be calculated by obtaining the particle diameter by image analysis with a transmission electron microscope (TEM) in an arbitrary range of at least 20 μm × 40 μm of the resin layer on the surface of the object to be plated. . At this time, at least 2000 particles are to be measured, and when there are a major axis and a minor axis, the average is taken as the particle diameter. Further, when observing with a transmission electron microscope, it is recommended that the resin layer be stained with a heavy metal such as osmium tetroxide in order to make it easier to confirm the rubbery polymer.

Examples of the unsaturated nitrile monomer that can be graft copolymerized with the rubbery polymer of the present embodiment include acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like.
These unsaturated nitrile monomers may be used individually by 1 type, and may use 2 or more types together.

Examples of the aromatic vinyl monomer that can be graft-copolymerized with the rubbery polymer of the present embodiment include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, o-ethylstyrene, Examples thereof include p-ethylstyrene, pt-butylstyrene, and vinylnaphthalene.
These aromatic vinyl monomers may be used alone or in combination of two or more.

In addition to the unsaturated nitrile monomer and aromatic vinyl monomer, the monomer mixture that can be graft copolymerized with the rubber polymer includes other monomers that can be graft copolymerized with the rubber polymer. A mer may be included.
Examples of such monomers include, but are not limited to, N-substituted maleimide monomers such as unsaturated carboxylic acid alkyl ester monomers, maleic anhydride, N-phenylmaleimide, N-methylmaleimide, and the like. And glycidyl group-containing monomers such as glycidyl methacrylate.
These may be used alone or in combination of two or more.

The method for producing the rubbery polymer constituting the graft copolymer (I) is not limited, and examples thereof include bulk polymerization, solution polymerization, suspension polymerization, bulk suspension polymerization, and emulsion polymerization. Can be used. Among these, a particle-shaped rubber component is obtained, and the particle diameter can be easily controlled, so that an emulsion polymerization method, a suspension polymerization method, and a bulk suspension polymerization method are preferably used.
When a polymer having a plurality of Tg is used as the rubbery polymer, those having different monomer compositions can be polymerized and produced in multiple stages. It is preferable to produce by multistage polymerization using an emulsion polymerization method.
In addition, when the rubbery polymer is a polymer having a composition gradient, the polymerization can be performed by continuously changing the monomer composition. For example, in emulsion polymerization, it can manufacture using what is called a power feed method.
When the rubber polymer is a block copolymer of an aromatic vinyl monomer and a diene vinyl monomer, for example, a styrene-butadiene block copolymer, it is produced by living anion polymerization in a solution. can do.

Further, there is no limitation on the method for producing the graft copolymer (I) containing the graft component (the method of graft polymerizing the monomer mixture onto the rubbery polymer). For example, the bulk polymerization method, the solution polymerization method, Methods such as turbid polymerization, bulk suspension polymerization, and emulsion polymerization can be used. In addition, after the production of the particulate rubber polymer, the graft polymerization may be continuously performed in the same reactor, or after the rubber polymer particles are once isolated as a latex, the graft polymerization is performed again. May be. When a radical initiator is used, an initiator such as peroxodisulfate or t-butylperoxy-2-ethylhexanoate can be used.
Among these, when producing by emulsion polymerization, a thermal decomposition type initiator that generates radicals by heat or a redox type initiator can be used. In the emulsion polymerization method, for example, a rubbery polymer obtained separately by emulsion polymerization may be used, and a method of emulsion polymerization of a monomer mixture containing an unsaturated nitrile monomer and an aromatic vinyl monomer may be used. it can. The graft portion obtained here is preferably compatible with the styrene copolymer (II) from the viewpoint of impact resistance.
When using the solution polymerization method, a diene monomer is subjected to living anion polymerization to obtain an uncrosslinked rubber polymer, and then the aromatic vinyl monomer and unsaturated nitrile monomer are dissolved. By performing polymerization together, a method obtained by precipitating a composite of a rubber component and a high Tg resin component can be used.

  In the graft copolymer (I), the ratio of the unsaturated nitrile monomer to the total amount of 100% by mass of the unsaturated nitrile monomer and aromatic vinyl monomer copolymerized is 20 to 50% by mass. It is preferable that A more preferable lower limit is 25% by mass, still more preferably 28% by mass, still more preferably 30% by mass, and most preferably 32% by mass. Moreover, a more preferable upper limit is 45 mass%, More preferably, it is 42 mass%, Most preferably, it is 40 mass%. In order to improve adhesiveness with a plating layer, it is preferable that it is 20 mass% or more, and in order to suppress the deterioration of the color of a molded object, it is preferable that it is 50 mass% or less.

  As an example of the most preferred embodiment as the graft copolymer (I), polybutadiene is used as a rubber polymer, and acrylonitrile is used as an unsaturated nitrile monomer and styrene is used as an aromatic vinyl monomer. The copolymer which was made is mentioned.

In the present embodiment, the content of the graft copolymer (I) contained in the thermoplastic resin composition and the rubbery polymer contained therein is not particularly limited, but the content of the rubbery polymer is 1 to 30 mass. %, And more preferably 1 to 20% by mass. In order to keep the adhesion strength with the plating layer high, the content of the rubbery polymer is desirably 1% by mass or more, and in order to suppress deterioration of the surface appearance of the plated product, it is 30% by mass or less. It is preferable.
In addition, content of the rubber-like polymer as used in the field of this invention can be calculated | required by the component analysis using a Fourier-transform infrared spectrophotometer (FT-IR). Specifically, using a calibration curve created using the peak values of multiple samples (thermoplastic resin composition) containing rubbery polymers with known concentrations, calculating the content Can do.

(Styrene copolymer (II))
The styrene copolymer (II) is a styrene copolymer having at least an unsaturated nitrile monomer and an aromatic vinyl monomer as constituent components.
Examples of the unsaturated nitrile monomer and aromatic vinyl monomer constituting the styrene copolymer (II) include the unsaturated nitrile monomer and aromatic vinyl monomer contained in the graft copolymer (I), respectively. The thing similar to what was mentioned above as a specific example of a monomer can be used.

The styrenic copolymer (II) may contain other monomers copolymerizable therewith. Examples of such monomers include, but are not limited to, N-substituted maleimide monomers such as unsaturated carboxylic acid alkyl ester monomers, maleic anhydride, N-phenylmaleimide, N-methylmaleimide, and the like. And glycidyl group-containing monomers such as glycidyl methacrylate.
These may be used alone or in combination of two or more.

The ratio of the unsaturated nitrile monomer unit to the total amount of 100% by mass of the unsaturated nitrile monomer unit and the aromatic vinyl monomer unit constituting the styrene copolymer (II) is 30 to 50% by mass. Preferably there is. A more preferable lower limit is 32% by mass, still more preferably 34% by mass, and most preferably 35% by mass. Moreover, a more preferable upper limit is 48 mass%, More preferably, it is 45 mass%, Most preferably, it is 40 mass%.
According to the study by the present inventors, when the ratio of the unsaturated nitrile monomer unit in the styrene copolymer (II) is higher than the general range (about 25 to 30% by mass), the thermoplastic resin composition It has been found that the adhesion between the object and the plating layer is increased. In order to obtain a sufficient adhesion strength between the plating layer and the object to be plated, the ratio of the unsaturated nitrile monomer unit is preferably 20% by mass or more. However, if it is too high, a styrene copolymer ( Since the impact resistance of the composition containing II) is lowered, it is preferably 50% by mass or less.

The styrenic copolymer (II) is dissolved in acetone. Therefore, the ratio of the unsaturated nitrile monomer unit to the total amount of the unsaturated nitrile monomer unit and the aromatic vinyl monomer unit constituting the styrene copolymer (II) is the resin layer portion of the plated product. Is soaked in acetone, the soluble component is taken out, and the component is analyzed using a Fourier transform infrared spectrophotometer (FT-IR). The specific procedure is shown below.
(Separation of acetone-soluble matter)
Prepare two centrifuge tubes per sample. First, the centrifuge tube is allowed to cool for 15 minutes or more in a desiccator and then precisely weighed to 0.1 mg with an electronic balance. Next, about 1 g is cut from the thermoplastic resin composition obtained by peeling the plating from the plated product, weighed into a centrifuge tube, and precisely weighed to 0.1 mg. In addition, about 20 mL of acetone is collected with a graduated cylinder, put into a centrifuge tube, put on a silicon stopper, and shaken with a shaker for 2 hours. After shaking, the sample adhering to the silicon stopper is dropped into the centrifuge tube using a small amount of acetone. Next, set the two centrifuge tubes diagonally to the rotor of a Hitachi high-speed cooling centrifuge manufactured by Hitachi Koki Co., Ltd., operate the Hitachi high-speed cooling centrifuge, and centrifuge for 60 minutes at a rotational speed of 20000 rpm. Do. After completion of the centrifugation, the sedimentation tube is taken out of the rotor, and the supernatant liquid is decanted. This supernatant can be dried at 80 ° C. for 1 hour and then dried under reduced pressure at 100 ° C. for 1 hour to obtain an acetone-soluble component.
(Measurement method of the ratio of unsaturated nitrile monomer)
Composition analysis can be performed using FT-IR from the acetone-soluble component obtained as described above. In this case, an unsaturated nitrile monomer unit is obtained using a calibration curve created using a peak value of a copolymer having a known content of unsaturated nitrile monomer unit and aromatic vinyl monomer unit. The ratio of the unsaturated nitrile monomer unit to the total amount of the unsaturated nitrile monomer unit and the aromatic vinyl monomer unit can be determined.

  In the present embodiment, the content of the styrenic copolymer (II) contained in the thermoplastic resin composition is not limited, but is 10% by mass or more from the viewpoint of maintaining high adhesion strength with the plating layer. Is preferable, more preferably 20% by mass or more, and still more preferably 30% by mass or more. Moreover, there is no limitation also about the upper limit, for example, it is good also as 80 mass% or less, good also as 70 mass% or less, and good also as 60 mass% or less.

(Additive)
In this embodiment, you may mix | blend and use an additive for a thermoplastic resin composition as needed. Examples of the additive include, but are not limited to, for example, phosphite-based, hindered phenol-based, benzotriazole-based, benzophenone-based, benzoate-based, and cyanoacrylate-based UV absorbers and antioxidants; higher fatty acids and acid esters. And acid amides, lubricants and plasticizers such as higher alcohols; release agents such as montanic acid and its salts, esters, half esters, stearyl alcohol, stellar amide and ethylene wax; Anti-coloring agents such as phosphates; Nucleating agents; Antistatic agents such as amines, sulfonic acids, and polyethers; 1,3-phenylenebis (2,6-dimethylphenyl phosphate), tetraphenyl-m- Lithium bisphosphate, phenoxyphosphoryl, phenoxyphosphazene, etc. And a halogen-based flame retardants; system flame retardant.

Examples of the lubricant include, but are not limited to, aliphatic metal salts, polyolefins, polyester elastomers, polyamide elastomers, and the like.
When these lubricants are blended and used, the preferred amount is 0.1 parts by mass or more and 10 parts by mass or less when the thermoplastic resin composition is 100 parts by mass.

Examples of the fatty acid metal salt include, but are not limited to, a metal and fatty acid salt containing at least one selected from sodium, magnesium, calcium, aluminum, and zinc. Specific examples of the fatty acid metal salt include, but are not limited to, for example, sodium stearate, magnesium stearate, calcium stearate, aluminum stearate (mono, di, tri), zinc stearate, sodium montanate, montanic acid Examples include calcium, calcium ricinoleate, and calcium laurate. Among the above, stearic acid-based metal salts such as sodium stearate, magnesium stearate, calcium stearate, and zinc stearate are preferable. Among the stearic acid-based metal salts, specifically, calcium stearate is more preferable.
When these are blended and used, the preferable amount is 0.1 parts by mass or more and 5 parts by mass or less when the thermoplastic resin composition is 100 parts by mass.

Although not limited to the following as said polyolefin, For example, the composition produced | generated from at least 1 or more types, such as ethylene, propylene, an alpha olefin, is mentioned, These are the compositions induced | guided | derived from this composition as a raw material Including. Specific examples include, but are not limited to, polypropylene, ethylene-propylene copolymer, polyethylene (high density, low density, linear low density), oxidized polyolefin, and graft polymerized polyolefin. Of these, oxidized polyolefin wax and polyolefin grafted with styrene resin are preferred, more preferably polypropylene wax, polyethylene wax, oxidized polypropylene wax, oxidized polyethylene wax, acrylonitrile-styrene copolymer grafted polypropylene, acrylonitrile- Styrene copolymer grafted polyethylene, styrene polymer grafted polypropylene, and styrene polymer grafted polyethylene.
When these are blended and used, the preferable amount is 0.1 parts by mass or more and 10 parts by mass or less when the thermoplastic resin composition is 100 parts by mass.

Examples of the polyester elastomer include, but are not limited to, for example, polycondensation of a dicarboxylic acid compound and a dihydroxy compound, ring-opening polycondensation of a polycondensation lactone compound of an oxycarboxylic acid compound, or polycondensation of a mixture of these components. And polyester obtained by the above. Either a homopolyester or a copolyester may be used.
When these are blended and used, the preferable amount is 0.1 parts by mass or more and 10 parts by mass or less when the thermoplastic resin composition is 100 parts by mass.
Examples of the dicarboxylic acid compound include, but are not limited to, terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, and diphenyl-4,4-dicarboxylic acid. , Aromatic dicarboxylic acids such as diphenoxyethanedicarboxylic acid, sodium 3-sulfoisophthalate, and aliphatic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, dicyclohexyl-4,4-dicarboxylic acid , Diphenyl ether dicarboxylic acid, diphenylethane dicarboxylic acid, succinic acid, oxalic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid and other aliphatic dicarboxylic acids, and mixtures of these dicarboxylic acids. Haloge And substituted are also included. These dicarboxylic acid compounds can also be used in the form of an ester-forming derivative, for example, a lower alcohol ester such as dimethyl ester. In this embodiment, these dicarboxylic acid compounds can be used alone or in combination of two or more. Of these, terephthalic acid, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, sebacic acid, adipic acid and dodecanedicarboxylic acid are preferred.
Examples of the dihydroxy compound include, but are not limited to, ethylene glycol, propylene glycol, butanediol, neopentyl glycol, butenediol, hydroquinone, resorcin, dihydroxy diphenyl ether, cyclohexane diol, hydroquinone, resorcin, dihydroxy diphenyl ether, cyclohexane diol, 2,2-bis (4-hydroxyphenyl) propane and the like, and these polyoxyalkylene glycols and their alkyl, alkoxy or halogen-substituted products are exemplified. These dihydroxy compounds can be used alone or in combination of two or more.
Examples of the oxycarboxylic acid compound include, but are not limited to, oxybenzoic acid, oxynaphthoic acid, diphenyleneoxycarboxylic acid, and the like, and these alkyl, alkoxy, and halogen substituted products are also included. These oxycarboxylic acid compounds can be used alone or in combination of two or more. A lactone compound such as ε-caprolactone can also be used for producing a polyester elastomer.

Examples of the polyamide elastomer include, but are not limited to, for example, aminocarboxylic acids or lactams having 6 or more carbon atoms, nylon mn salts having m + n of 12 or more, and the hard segment (X) is limited to the following. For example, aminocarboxylic acids such as ω-aminocaproic acid, ω-aminoenanoic acid, ω-aminocaprylic acid, ω-aminobergonic acid, ω-aminocapric acid, 11-aminoundecanoic acid, 12-aminododecanoic acid; caprolactam Lactams such as laurolactam, nylon 6,6, nylon 6,10, nylon 6,12, nylon 11,6, nylon 11,10, nylon 12,6, nylon 11,12, nylon 12,10, nylon 12, Nylon salts such as 12. In addition, the soft segment (Y) such as polyol includes polyethylene glycol, poly (1,2- and 1,3-propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, and ethylene oxide. Examples thereof include a block or random copolymer of propylene oxide and a block or random copolymer of ethylene oxide and tetrahydrofuran. The number average molecular weight of these soft segments (Y) is preferably 2.0 × 10 ^{2 to} 6.0 × 10 ³ , more preferably 2.5 × 10 ^{2 to} 4.0 × 10 ³ . The number average molecular weight can be measured as a styrene equivalent molecular weight by comparison with standard polystyrene by gel permeation chromatography (GPC). Note that both ends of poly (alkylene oxide) glycol may be aminated or carboxylated.

In the present embodiment, when a lubricant is added to the thermoplastic resin composition, an acid-modified or epoxy-modified modified resin may be further mixed for the purpose of improving the compatibility.
Further, a part of the thermoplastic resin composition may be acid-modified or epoxy-modified. For example, the graft copolymer (I) or the styrene copolymer (II) contained in the thermoplastic resin composition is copolymerized with a vinyl monomer containing a carboxyl group or a glycidyl group. Etc.
When using these, the preferable quantity is 0.1 to 10 mass parts when the whole thermoplastic resin composition is 100 mass parts.
Examples of the vinyl monomer containing a carboxyl group include, but are not limited to, unsaturated compounds containing a free carboxyl group such as acrylic acid, crotonic acid, cinnamic acid, itaconic acid, maleic acid, maleic anhydride, Examples thereof include unsaturated compounds containing an acid anhydride-type carboxyl group such as itaconic anhydride, chloromaleic anhydride, and citraconic anhydride. Among these, acrylic acid, methacrylic acid, and maleic anhydride are preferable. .
Examples of the vinyl monomer containing the glycidyl group include, but are not limited to, glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, methyl glycidyl ether, methyl glycidyl methacrylate, and the like. Glycidyl is preferred.

(Method for producing thermoplastic resin composition)
The thermoplastic resin composition constituting at least the surface of the plated product of the plated product according to the present embodiment is a thermoplastic resin composition such as a single-screw or twin-screw extruder, plastmill, kneader, Banbury mixer, Brabender, etc. It can manufacture by mixing a raw material using the various mixing apparatuses generally used for manufacture of a composition.

<Plating products>
As for the plating product of this embodiment, it is desirable that the adhesion strength of the plating layer by the measuring method based on JISH8630 and a to-be-plated body is 5 N / cm or more. It is possible to obtain a plating layer having such a strong adhesion while having a smooth surface appearance by making the surface of the object to be plated smooth without large unevenness and infiltrating the catalyst metal into the resin. It is quite surprising considering the conventional technical common sense.
The adhesion strength is more preferably 8 N / cm or more, even more preferably 9 N / cm or more, and most preferably 10 N / cm or more. There is no particular upper limit, and the upper limit varies depending on the strength at which the material destruction of the resin molding occurs. When the adhesion strength is within this range, plating peeling during actual use can be prevented.

In the present embodiment, the thickness of the plating layer can be appropriately adjusted depending on the purpose, but is preferably 0.5 μm to 30 μm. More preferably, they are 1 micrometer-20 micrometers, More preferably, they are 1.5 micrometers-25 micrometers, Most preferably, they are 2 micrometers-10 micrometers. By being 0.5 μm or more, the appearance is more excellent. Moreover, it becomes easier to trace the surface shape of a to-be-plated body because it is 30 micrometers or less, and the time load in a plating process process also becomes small. In general, in order to achieve a surface appearance having a clean metallic luster without fogging, the thickness of the plating layer is required to be 40 μm or more. However, in the plating product of this embodiment, the thickness of the plating layer is 30 μm or less. Even if it exists, a favorable surface external appearance can be implement | achieved.
The thickness of the plating layer can be measured based on JIS H8501. Specifically, an ultra-thin slice created by the FIB method from the cross section of the plated product (cross section perpendicular to the tangential plane of the plated surface of the product) is observed by STEM, from the plated layer surface to the surface of the object to be plated in contact with the plated layer Are measured at three locations for each visual field, and a total of 30 are measured for any 10 visual fields, and the average value thereof is defined as the plating layer thickness.

<Method of manufacturing the object to be plated>
The body to be plated in the present embodiment is not particularly limited as long as it has the above-described resin layer on the surface. For example, a molded body manufactured by a known molding method or the like can be used. For example, any of press molding, injection molding, gas assist injection molding, welding molding, extrusion molding, blow molding, film molding, hollow molding, multiphase molding, foam molding, and the like may be used. In the injection molding method, insert molding with metal, outsert molding, gas assist molding, or the like may be used in combination. The die used is not particularly limited, and the gate shape may be any kind of pin gate, tab gate, film gate, submarine gate, fan gate, ring gate, direct gate, disk gate, and the like.

<Plating method>
A plated product can be obtained by plating the object to be plated. There is no limitation on the plating treatment, and a known method can be adopted. In the present embodiment, for example, each step of etching, surface adjustment, catalyst application, activation, catalyst application, and electroless plating is sequentially performed. It is preferable.

(Etching process)
There is no limitation on the etching method in the etching step, and for example, known etching methods such as ultraviolet irradiation, immersion in ozone water, combined use of ultraviolet irradiation and ozone water immersion can be used. From the viewpoint of setting the thickness to 200 nm or less, it is preferable to perform ultraviolet irradiation.
When ultraviolet irradiation is performed, the light source to be used is not particularly limited, and examples thereof include a low pressure mercury lamp, a high pressure mercury lamp, and an excimer lamp. Although the illuminance of ultraviolet rays is not particularly limited, it is preferable illuminance is 5mW / cm ² ~150mW / cm ² at a wavelength of 254 nm. When the illuminance is 5 mW / cm ² or more, the adhesion strength tends to be more excellent. Moreover, it exists in the tendency for the surface appearance of a plating layer to become the more excellent in it being 150 mW / cm < ² > or less. The irradiation time of ultraviolet rays is preferably 0.1 minutes to 50 minutes. More preferably, it is 0.2 to 40 minutes, and most preferably 0.3 to 30 minutes. Sufficient adhesion strength is obtained when the time is 0.1 minutes or longer, and the surface appearance tends to be more excellent when the time is 50 minutes or shorter.

(Surface adjustment step 1)
After the etching step, surface adjustment 1 may be performed in which the object to be plated is immersed in a treatment liquid for cleaning the surface of the object to be plated and imparting wettability.
The processing liquid used for the surface adjustment 1 can use a well-known thing, for example, CP conditioner (made by Kizai Co., Ltd.) etc. are mentioned. When using a CP conditioner, the temperature of the treatment liquid is preferably 30 to 60 ° C., and the immersion time is preferably 1 to 5 minutes. By treating under these conditions, the plating deposits evenly and is more excellent in adhesion strength.

(Surface adjustment step 2)
In order to make it easy to deposit the catalyst in the catalyst application step, after the etching step (or after the surface adjustment step 1), surface adjustment 2 in which the object to be plated is immersed in the treatment liquid may be performed.
The treatment agent contained in the treatment liquid used for the surface conditioning 2 may be any substance that can be adsorbed to both the functional group and the catalyst on the surface of the object to be plated etched by ultraviolet irradiation. As such a compound, a polyvalent amine is preferable, and specifically, ethyleneamine, polyethyleneimine, polyethyleneamine, and polyallylamine are more preferable. Among these, polyallylamine and polyethyleneimine are particularly preferable. By using these substances, the adhesion strength is further improved.
When polyallylamine is used as the treating agent, the concentration in the treating solution is preferably 0.01 g / l to 10 g / l, more preferably 0.1 g / l to 1 g / l.
30-60 degreeC is preferable and the temperature of a process liquid has more preferable 35-50 degreeC. The treatment time is preferably 1 to 10 minutes, more preferably 1 to 5 minutes. By treating under these conditions, it is possible to realize a plating layer with no unevenness and better adhesion strength.

(Catalyst application process)
The catalyst can be applied after the surface adjustment. In the catalyst application step, the object to be plated after the surface adjustment is treated with a solution containing a metal complex, and the metal complex is supported on the surface of the object to be plated.
Although there is no restriction | limiting in particular as a metal complex, A palladium complex, a copper complex, and a silver complex are preferable, and palladium chloride is more preferable. When palladium chloride is used, the palladium chloride concentration in the solution is preferably 50 to 500 mg / l.
The solution is preferably an acidic aqueous solution, more preferably hydrochloric acid or sulfuric acid aqueous solution. The acid concentration in the aqueous solution is preferably 10 to 100 g / l. The temperature of the solution containing the metal complex is preferably 30 to 60 ° C., and the immersion time is preferably 1 to 5 minutes. By treating under these conditions, it is possible to realize a plating layer with better appearance and adhesion strength.

(Activation process)
It is preferable to perform activation after applying the catalyst. In the activation step, the object to be plated after applying the catalyst is treated with a solution containing a reducing agent to activate the catalyst. Although there is no restriction | limiting in particular as a reducing agent, Hydrogen, sodium hypophosphite, and sodium borohydride are preferable, and sodium hypophosphite is more preferable. When sodium hypophosphite is used, the reducing agent concentration in the solution is preferably 0.1 to 100 g / l, more preferably 5 to 100 g / l.
The solution is preferably an aqueous solution. The temperature of the solution containing the reducing agent is preferably 30 to 60 ° C., and the immersion time is preferably 1 to 5 minutes. By treating under these conditions, it is possible to realize a plating layer with better appearance and adhesion strength.

(Electroless plating process)
Electroless plating is performed after the activation step (after the catalyst application step if no activation treatment is performed). A known electroless plating method can be adopted for the electroless plating. For example, copper plating, nickel plating, palladium plating, silver plating, gold plating, and alloy plating thereof can be used according to the purpose.

(Electrolytic plating process)
Electrolytic plating may be further performed after electroless plating. Electrolytic plating can be used without particular limitation depending on the purpose, such as designability and anticorrosion.

  Hereinafter, although this embodiment is described more specifically using examples and comparative examples, this embodiment is not limited to the following examples.

In the examples and comparative examples, the following raw materials were used.
In addition, the composition of each copolymer is a value obtained as a result of composition analysis using FT-IR.
[Graft Copolymer (I)]
The following ABS resins (A-1) and (A-2) containing the graft copolymer (I) were used.
(A-1)
An ABS resin having a rubbery polymer (butadiene) content of 30% by mass and a graft copolymer (I) content of 45%.
The graft ratio of the graft copolymer (I) is determined by using a solvent (acetone in this embodiment) to remove the solvent-soluble component from the resin portion and taking out the graft copolymer (I) as the solvent-insoluble component. The mass of the rubbery polymer and other components (that is, the graft polymerized monomer) in the graft copolymer (I) is measured by a Fourier transform infrared spectrophotometer (FT-IR), From the value, it was determined as the ratio of the mass of the graft polymerized monomer to the mass of the rubbery polymer.
Moreover, (A-1) also contains styrene-type copolymer (II) as an acetone soluble part, The content was 56.5 mass%.
(A-2)
An ABS resin having a rubbery polymer (butadiene) content of 36% by mass and a graft copolymer (I) content of 37%.
Moreover, (A-2) also contains styrene-type copolymer (II) as an acetone soluble part, The content was 50.7 mass%.

[Styrene copolymer (II)]
As the styrene copolymer (II), not only the styrene copolymer (II) contained in the ABS resin of the above (A-1) or (A-2), but also the following (II-1) and ( II-2) was mixed and used.
(II-1)
AS resin (II-2) having 40% by mass of acrylonitrile units and 60% by mass of styrene units
AS resin having 27% by mass of acrylonitrile units and 73% by mass of styrene units

(Measurement of maximum unevenness of resin surface)
An ultrathin section was prepared from the cross section of the plated product by the FIB method, and STEM observation was performed at 10 locations in a field of 1.7 × 2.5 μm. The maximum value of the unevenness on the surface of the object to be plated (the surface of the resin layer in contact with the plating layer) in each field of view was measured, and the average value of 10 values was defined as the unevenness of the unevenness.
(Measurement of plating layer thickness)
The ultrathin sections prepared above were observed with a STEM, and the thicknesses of any three plating layers were measured in each of 10 fields of view, and the average value of a total of 30 places was defined as the plating thickness.

Example 1
(A-1) After mixing 55 parts by mass and (II-1) 45 parts by mass, using a twin screw extruder (TEM-35B, manufactured by Toshiba Machine Co., Ltd.), a cylinder set temperature of 250 ° C., screw rotation After kneading at several 200 rpm, it was cooled and cut in a water bath to obtain a thermoplastic resin composition pellet. Unsaturated nitrile monomer with respect to the total amount of unsaturated nitrile monomer units and aromatic vinyl monomer units constituting styrene copolymer (II) in the acetone-soluble component of this thermoplastic composition The unit ratio (P) was 40% by mass. Thereafter, using an injection molding machine (EC-60N, manufactured by Toshiba Machine Co., Ltd.), a flat plate of 90 mm × 50 mm × 2.5 mm at a barrel set temperature of 250 ° C., a mold temperature of 60 ° C., and an injection speed of 25 mm / s. Was molded.
Using this flat plate as a body to be plated, the following treatment was performed to obtain a plated product.
(1) Ultraviolet irradiation step The molded flat plate was irradiated with ultraviolet rays for 3 minutes at an irradiation distance of 50 cm using KOV1-30H (manufactured by Koto Electric Co., Ltd.).
(2) Surface adjustment step 1
The molded body after the ultraviolet irradiation step was immersed in an aqueous solution to which CP conditioner (manufactured by Kizai Co., Ltd.) was added to a concentration of 100 mL / L and sodium hydroxide to a concentration of 30 g / L at 50 ° C. for 2 minutes.
(3) Surface adjustment step 2
The molded body after the surface adjustment step 1 was immersed in an aqueous solution to which CP-COND 1256 (manufactured by Kizai Co., Ltd.) was added to a concentration of 50 mL / L at 40 ° C. for 2 minutes.
(4) Catalyst application step The molded body after the surface adjustment step 2 was added to an aqueous solution in which EP ActiPAC (manufactured by Kizai Co., Ltd.) was added to a concentration of 30 mL / L and 35% hydrochloric acid to a concentration of 35 mL / L. It was immersed for 2 minutes at 40 ° C.
(5) Activation step The molded body after the catalyst application step was immersed in an aqueous solution to which EP Accel PA Conk (manufactured by Kizai Co., Ltd.) was added to a concentration of 20 mL / L at 40 ° C for 2 minutes.
(6) Electroless plating step The molded body after the activation step is added to an aqueous solution in which Nyco SLE (manufactured by Kizai Co., Ltd.) A solution and B solution are added to a concentration of 125 mL / L at 35 ° C. It was immersed for 10 minutes and electroless plating (nickel) was performed.

(Example 2)
A plated product was obtained in the same manner as in Example 1 except that the ultraviolet irradiation time in the ultraviolet irradiation step was 1 minute.

(Example 3)
A plated product was obtained in the same manner as in Example 1 except that the ultraviolet irradiation time in the ultraviolet irradiation step was 0.1 minute.

Example 4
A plated product was obtained in the same manner as in Example 1 except that the ultraviolet irradiation time in the ultraviolet irradiation step was 10 minutes.

(Example 5)
A plated product was obtained in the same manner as in Example 2 except that (A-2) 45 parts by mass and (II-2) 55 parts by mass were used as raw materials. Unsaturated nitrile monomer based on the total amount of unsaturated nitrile monomer units and aromatic vinyl monomer units constituting the styrene copolymer (II) in the acetone-soluble component of the used thermoplastic composition The ratio (P) of the body unit was 27% by mass.

(Comparative Example 1)
The following treatment was performed on the flat plate obtained in the same manner as in Example 1 to obtain a plated product.
(A) Etching Step The shaped flat plate was immersed in an aqueous solution prepared by adjusting 98% by mass sulfuric acid so that the chromium trioxide concentration was 400 g / L and the sulfuric acid concentration was 400 g / L at 68 ° C. for 10 minutes.
(B) Neutralization process The molded body after the etching process was immersed in an aqueous solution prepared by adjusting 35 mass% hydrochloric acid to 50 mL / L at room temperature for 1 minute.
(C) Catalyst application process The molded body after the neutralization process is an aqueous solution prepared by adjusting 35 mass% hydrochloric acid so that the concentration of CP Cat 5 (manufactured by Kizai Co., Ltd.) is 12 mL / L and the hydrochloric acid concentration is 200 mL / L For 3 minutes at 35 ° C.
(D) Activation process The molded object after a catalyst provision process was immersed for 3 minutes at 35 degreeC in the aqueous solution which adjusted 35 mass% hydrochloric acid to 80 mL / L.

(E) Electroless Plating Process The molded body after the activation process was adjusted to an aqueous solution prepared by adjusting the liquid A and liquid B of Nyco SLE (manufactured by Kizai Co., Ltd.) to a concentration of 125 mL / L at 35 ° C. Soaked for 10 minutes.

(Comparative Example 2)
A plated product was obtained in the same manner as in Comparative Example 1 except that the immersion time in the step (e) was adjusted so that the thickness of the plating layer was 15 μm.
(Measurement of adhesion strength)
In order to make it possible to measure the adhesion strength, the molded body (plated product) after the electroless plating process is subjected to electrolysis using a plating bath consisting of the following, bath temperature 20 ° C., current density 3 A / dm ² , 60 minutes. Plating was applied. A smooth portion was cut out from this molded body, and the adhesion strength was measured based on JIS H8630.
<Composition of electrolytic plating bath>
Copper sulfate 200g / L
Sulfuric acid 60g / L
Chloride ion 60mg / L
Kotak Makeup 4mL / L
Kotak 1 0.5mL / L
(Appearance evaluation)
The visual appearance of the plated product was judged according to the following criteria.
◎: No cloudiness and beautiful metallic luster ○: Partially cloudy but metallic luster △: Mostly cloudy and almost no metallic luster ×: Whole cloudy and metallic luster Absent

The results are shown in the table below.

The plated product of Example 1 was excellent in both adhesion strength and appearance.
Compared with Example 1, the plated product of Example 2 is sufficiently practical, although the adhesion strength is slightly reduced due to the fact that the maximum height difference of the unevenness on the surface of the object to be plated is reduced. Met.
Compared with the product of Example 2, the plating product of Example 3 has an even lower adhesion strength due to a further decrease in the maximum value of the unevenness on the surface of the object to be plated, but it can withstand practical use. It had adhesion strength.
The plated product of Example 4 has a higher maximum value of the surface unevenness of the surface of the object to be plated than that of Example 1, so that the appearance was partially cloudy, but it was practical. Met.
In the plated product of Example 5, the ratio of the unsaturated nitrile monomer unit to the total amount of the unsaturated nitrile monomer unit and the aromatic vinyl monomer unit in the styrene copolymer (II) was measured. Compared with 40 mass% of Example 2, it was as low as 30 mass%, and the adhesive strength was smaller than that of Example 2.
The plated product of Comparative Example 1 was inferior in appearance because the maximum value of the unevenness of the object to be plated was 300 nm.
The plating product of Comparative Example 2 has a maximum unevenness of the unevenness of the object to be plated of 300 nm as in Comparative Example 1. Even if the plating layer is thicker than Comparative Example 1, the appearance is practical. It was not suitable.

(Example 6)
A plated product was obtained in the same manner as in Example 1 except that the shape of the object to be plated was changed from a flat plate to a toy saw blade shape having a flow length of 400 mm, a width of 20 mm, and a thickness of 2 mm as shown in FIG. In addition, a part of one side surface of the object to be plated has a saw blade shape with a blade pitch of 1.8 mm and a kerf width of 0.8 mm. In FIG. 2, the “gate position” is a portion corresponding to the inlet through which the thermoplastic resin composition is injected into the mold when the object to be plated is formed.
The maximum value of the unevenness on the surface of the object to be plated was 52 nm, the adhesion strength of the plated product was 16 N / cm, and the thickness of the plating layer was 11 μm.
The appearance of this plated product was clean and had a beautiful metallic luster. Furthermore, when the folded paper is cut using the saw blade part at the flow end of this plated product (the part shown in the figure as “used for testing”), it can be cut cleanly with little resistance. It was.

(Comparative Example 3)
A toy saw blade-shaped plated product was obtained in the same manner as in Comparative Example 1 except that the shape of the object to be plated was the same as that in Example 6. The maximum unevenness of the surface of the object to be plated was 315 nm.
However, the appearance of this plated product was entirely cloudy and did not have a metallic luster. Therefore, when the thickness of the plated layer was increased until it showed a clean metallic luster without fogging, the thickness of the plated layer became 40 μm. The adhesion strength was 7 N / cm.
When the folded paper was cut using the saw blade portion at the flow end of this plated product in the same manner as in Example 6, the resistance was so great that it could not be cut cleanly.

  Since the plated product of the present invention is excellent in adhesion strength and appearance, it can be suitably used in various applications such as automotive applications, household appliance applications, and electronic device applications.

Claims (4)

A plated product having a body to be plated having a resin layer containing a thermoplastic resin composition on the surface, and a plating layer provided thereon,
The thermoplastic resin composition comprises at least a graft copolymer (I) obtained by graft copolymerization of a rubber mixture with a monomer mixture containing at least an unsaturated nitrile monomer and an aromatic vinyl monomer. A styrene copolymer (II) comprising a saturated nitrile monomer and an aromatic vinyl monomer as constituent components,
The maximum value of the height difference of the unevenness of the surface of the object to be plated is 200 nm or less,
Plating product.   The plated product according to claim 1, wherein the adhesion strength between the plated layer and the object to be plated by a measuring method based on JIS H8630 is 5 N / cm or more.   When the total amount of the unsaturated nitrile monomer unit and the aromatic vinyl monomer unit is 100% by mass, the styrene copolymer (II) is 30 to 50% by mass of the unsaturated nitrile monomer unit. The plated product according to claim 1, comprising:   The manufacturing method of the plating product of any one of Claims 1-3 including the etching process by ultraviolet irradiation.