Method for manufacturing a partially plated product and partially plated product

Abstract

To provide a method for manufacturing a partial plating product that can improve the working environment of a person, and that can peel off a masking agent in a short time even if the peeling agent is safe for the human body after plating, and to provide a partial plating product. 【Solution means】An oil-based ink containing rosin resin and alcohols as main components is used as a masking agent to form a coating film layer 20 on a plating base material 10, and by volatilizing the alcohols from the coating film layer, a consolidated film 30 mainly composed of rosin resin is formed. Further, a plating layer 50 is formed on the portion of the plating base material where there is no consolidated film by plating treatment with an acidic bath that does not dissolve the consolidated film. Alcohols have less eye irritation and irritating odor than thinners, are safe for the human body, so the working environment can be improved, and a consolidated film can be formed in a short time. Also, the rosin resin forming the consolidated film can be easily peeled off with alcohols.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a partially plated product in which a plating layer is formed on a part of the surface of a plating base material, and to a partially plated product. More specifically, it relates to a method for manufacturing a partially plated product in which a plating base material is masked with an oil-based ink that has low eye irritation and pungent odor and does not deteriorate the working environment of humans, and after the plating process, the masking agent can be peeled off in a short time with a peeling agent that is safe for the human body, and to a partially plated product.

[0002] More specifically, it relates to a method for manufacturing a partially plated product in which the masking agent is an oil-based ink mainly composed of ethanol that is safe for the human body and volatilizes quickly and a rosin resin that can be easily peeled off with ethanol, and the plating process is performed with an acidic solution that does not dissolve the rosin resin, and to a partially plated product. In the present application, the acidic solution refers to a solution having a pH of 7.0 or less that does not dissolve the rosin resin.

Background Art

[0003] Conventionally, as a method for manufacturing a partially plated product, a method of masking a part of a plating base material and forming a plating layer only on the remaining part has been a well-known technique. There are mainly two methods for this well-known technique. The first method is a method of applying a masking agent made of a resin-based paint, and the second method is a method of covering a plating base material with a heat-shrinkable tube, a masking tape, or the like. The invention of the present application belongs to the technology of the first method.

[0004] The first method has the advantage that when applied by an operator, masking is possible even on a complex uneven surface, and according to silk screen printing or the like, a precise mask such as a circuit pattern of a printed circuit board can be formed. However, in the first method, there is a problem that it is necessary to peel off the masking agent with an organic solvent such as thinner after plating.

[0005] By the way, in the plating factory, manufacturing lines such as plating treatment using an acidic bath and plating treatment using an alkaline bath are mixed. Since it is prohibited to directly drain the organic solvent, there is a situation where a masking agent that can be peeled off with a stripping agent (organic solvent) common to both the acidic bath and the alkaline bath is selected so that the drainage treatment can be easily performed.

[0006] However, for the resin coating for plating that is resistant to both acids and alkalis, a thinner mainly composed of highly toxic substances such as toluene, xylene, methanol, ethyl acetate, and methyl ethyl ketone is used as the organic solvent. Therefore, it has strong eye irritation and irritating odor, which deteriorates the working environment and also causes health problems for the workers.

[0007] In addition, the resin coating for plating has a high viscosity to prevent dripping. Therefore, the film thickness of the coating film layer is thick, and it takes several hours to half a day for the coating film layer to cure and dry. Furthermore, when the plating base material is a three-dimensional object such as a mechanical part, even if the three-dimensional object just falls down while the coating film layer is uncured, the coating film layer will touch the workbench or the like and peel off to become a defective product. Therefore, it is necessary to keep the plating base material standing still, resulting in poor workability.

[0008] Here, the drying state of the coating film layer will be explained in advance. In this application, the drying state of the coating film layer complies with the Japanese Industrial Standard Paint General Test Method (JIS K 5600). Specifically, curing and drying means that "when the center of the painted surface is strongly pinched between the thumb and the index finger, there is no indentation due to fingerprints on the painted surface, the movement of the coating film cannot be felt, and when the center of the painted surface is rapidly rubbed repeatedly with the fingertip, there is no rubbing mark on the painted surface." Hereinafter, the state where the applied masking agent is uncured is referred to as the coating film layer, and the state where it is cured and dried is referred to as the solidified film to distinguish the terms.

[0009] As described above, since the resin coating for plating easily forms a thick solidified film, even when it is immersed in the thinner stored in the cleaning tank and ultrasonic cleaning is performed, it takes 20 minutes or more for the solidified film to peel off. Moreover, often, even after ultrasonic cleaning, the solidified film remains partially adhered, and workers have been scraping off the solidified film with a brush, cloth, etc.

[0010] Therefore, for example, when coating a simple-shaped part such as the shaft part of a piston, the second method using a heat-shrinkable tube was actually superior in workability. However, in the second method, pinholes are generated when the heat-shrinkable tube is heated, and there is a possibility that a plating layer is formed in the pinhole part, resulting in product defects. In addition, there was a problem that it could only be applied when the masking part had a simple shape.

[0011] Patent Document 1 discloses a partial plating method technology applied by the applicant. According to the technology described in this document, a specific example is disclosed in which the masking agent is a resin coating for plating composed of an inactive hydrocarbon derivative, a coloring agent, and hydrogenated petroleum naphtha (such as toluene and xylene), and the release agent is the thinner contained in the masking agent.

[0012] However, even with this technology, both the masking agent and the release agent were thinners with strong eye irritation and irritating odors. Toluene, etc. contained in the thinner is excellent as a solvent because a wide range of resins are soluble, but since it is a narcotic and toxic, there is a problem that even with thorough ventilation, there is a possibility that acute poisoning symptoms may occur in workers. Also, since the thickness of the solidified film was thick, it took 10 to 30 minutes for peeling, and the problem of time-consuming peeling could not be solved.

[0013] Patent Document 2 discloses a technology of an ultraviolet-curable resin composition for a plating resist (hereinafter simply referred to as a paint). According to this technology, the paint is applied to a plating base material by a screen printing method or the like to form a coating film layer having a desired shape, and then the coating film layer is cured by irradiating ultraviolet rays. Further, the thickness of the coating film layer is set to 12 μm, and a specific example of using an aqueous sodium hydroxide solution as a release agent is disclosed.

[0014] However, according to the technology described in this document, it is necessary to irradiate ultraviolet rays to cure the paint. Then, when applying the paint to a plurality of surfaces of a three-dimensional object such as a machine part, if ultraviolet rays are irradiated from only one direction, the coating film layer on the surface that becomes a shadow may not be cured. Then, there is a problem that it is necessary to irradiate ultraviolet rays in multiple times, which is time-consuming.

[0015] In addition, since the coating film layer remains uncured until the integrated light amount of ultraviolet rays reaches a predetermined amount, when applying to a three-dimensional object that cannot use screen printing, it is necessary to select a paint with a higher viscosity than when printing on a flat surface to prevent dripping. Then, when applying the paint of this technology to the three-dimensional object, the coating film layer is likely to be thicker than in printing, and the time required for peeling may also be longer.

[0016] Since the present applicant has found that it is easily peeled off in many plating processes, the applicant has once again focused on various oil-based inks that have not been used as masking agents in the past and has conducted intensive research. As a result, by combining the plating process using an acidic bath and the oil-based ink that has only been used in writing instruments, it has been found that it is possible to achieve both improvement of the working environment and quick drying and easy peeling of the masking agent, and the present invention has been invented.

Prior Art Documents

Patent Documents

[0017] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-183877 Patent Document 2: Japanese Patent Application Laid-Open No. 2020-105549

Summary of the Invention

Problems to be Solved by the Invention

[0018] The problems to be solved by the present invention are to mask a plating base material with an oil-based ink having little eye irritation and irritating odor and not deteriorating the working environment, and even if it is a stripper safe for the human body after the plating process, to provide a method for manufacturing a partial plating product capable of peeling the solidified film in a short time, and a partial plating product.

Means for Solving the Problems

[0019] A first invention of the present invention is a method for manufacturing a partial plating product in which a masking agent is applied to a part of the surface of a plating base material, and a plating layer is formed on the remaining part of the plating base material that is not masked, including the first step to the fourth step in order. The first step is a degreasing step of degreasing the surface of the plating base material. The second step is an application step of applying an oil-based ink containing a resin and a solvent as main components as the masking agent to the degreased part to form a coating film layer. The third step is a solidified film forming step of forming a solidified film by volatilizing the solvent contained in the coating film layer. The fourth step is a plating treatment step of forming the plating layer only on the remaining part where the solidified film is not formed by an acidic bath. Further, the application step is a step of forming the coating film layer by applying an oil-based ink in which the main component of the resin constituting the oil-based ink is a rosin resin and the main component of the solvent is ethanol that dissolves the rosin resin. The solidified film forming step is characterized in that the solidified film having a main component of the rosin resin is formed with an average film thickness of 0.4 μm or more and 3.0 μm or less.

[0020] Since degreasing in the first step is the step before applying the masking agent, it may be any well-known alkaline degreasing or electrolytic degreasing, and the degreasing method is not limited. The material of the plating base material may be a conductor, such as copper, brass, nickel, iron, stainless steel, etc. in the case of electroplating, or may be a non-conductor in the case of electroless plating. The conductor may be an article with a plating layer formed on its surface. The plating base material is preferably a three-dimensional object such as a gear or a piston, but is not limited thereto and may be a flat plate-like object such as a printed circuit board.

[0021] For the application of the oil-based ink in the second step, it is preferable to impregnate the fibrous pen tip with the oil-based ink and apply it to the plating base material like a writing instrument. However, for a plating base material having a wide flat surface, it may be applied by a coating roller, screen printing, or spraying. The oil-based ink contains a resin for forming a solidified film and a solvent. The main component of the resin is a rosin resin, and the main component of the solvent is ethanol. As ethanol volatilizes from the coating film layer, a solidified film mainly composed of rosin resin is formed on the plating base material.

[0022] Since almost all of the ethanol volatilizes from the coating film layer, the weight ratio of rosin resin to ethanol in the oil-based ink is not limited. In addition, if the content ratio of ethanol to the total weight of the oil-based ink is, for example, 50% by weight or more, the viscosity of the oil-based ink becomes low, the coating operation becomes easy, and it is preferable because it is easier to form a thinner solidified film. The thin solidified film has a short time for curing and drying of the coating film layer, and the solidified film is also easily peeled off.

[0023] Ethanol is soluble in rosin resin, causes little health damage to workers, and has a low environmental impact. In addition, the oil-based ink may contain, as sub-components, a coloring agent (pigment / dye), a dispersant for the coloring agent, other resins, other solvents, etc. in addition to rosin resin and ethanol. A specific example of such an oil-based ink is an oil-based marking pen which is a writing instrument.

[0024] In the third step, volatilization means that ethanol, which is a solvent, becomes a gas and is emitted from the coating film layer under normal temperature and pressure conditions. In the step of forming a consolidated film, a consolidated film with a film thickness of at least 0.4 μm or more may be formed. Ethanol can be volatilized from the coating film layer without heating or ultraviolet irradiation to form a consolidated film, and moreover, it has weaker eye irritation and pungent odor compared to thinner, and is less likely to cause health hazards.

[0025] The test results are shown in the examples. The consolidated film formed with the oil-based ink of the present invention had an average film thickness of about 0.4 μm. This is about one-thirtieth of the film thickness compared to Patent Document 2 described above, and when immersed in ethanol stored in an ultrasonic cleaning tank, the consolidated film could be removed in about 10 seconds. The film thickness of the consolidated film is described in detail in the examples together with electron micrographs.

[0026] In the fourth step, the plating treatment with an acidic bath may be, for example, electroless nickel plating treatment, electroplating nickel plating treatment, electroplating copper plating treatment, zinc plating treatment with a zinc chloride bath, etc. In any case, since it is a plating treatment with an acidic bath, the consolidated film mainly composed of rosin resin is not dissolved in the plating solution. The plating treatment may include an activation treatment in which the plating base material is immersed in an acidic solution prior to immersion in the plating solution to roughen its surface in order to improve the adhesion between the plating base material and the plating layer.

[0027] According to the first invention, an oil-based ink mainly composed of rosin resin and ethanol is used as a masking agent, and only an acidic solution that does not dissolve rosin resin is used for the activation treatment and plating treatment of the plating base material. Thereby, compared with the conventional resin coating for plating, the curing and drying of the coating film layer are significantly faster, the production efficiency of the partially plated product can be increased, and since it is less likely to cause health hazards to the workers, it is possible to improve the working environment, which is an advantageous effect not found in the prior art.

[0028] The manufacturing method of the partial plating product of the second invention of the present invention is the first invention, wherein the coating step is a step of coating the oil-based ink containing ethanol at a ratio of 50% by weight or more and 90% by weight or less with respect to the total weight of the oil-based ink, and in the solidification film forming step, the ethanol is volatilized within 1 minute without depending on heating or ultraviolet irradiation to form the solidification film, which is characterized in that.

[0029] According to the second invention, in the coating step, an oil-based ink containing ethanol at a ratio of 50% by weight or more and 90% by weight or less is applied. Since the viscosity of the oil-based ink is low, a coating film layer with a thin film thickness can be applied, and ethanol can be quickly volatilized from the coating film layer even in a normal temperature environment to form a solidification film within 1 minute.

[0030] Thereby, heating and ultraviolet irradiation are not required for the curing and drying of the coating film layer, and the production efficiency of the partial plating product can be improved. In the present application, the normal temperature environment refers to an environment of 20°C ± 15°C defined in Japanese Industrial Standard (JIS Z 8703).

[0031] The manufacturing method of the partial plating product of the third invention of the present invention is the second invention, and includes a first management step of managing the number of times the oil-based ink is applied repeatedly. In the first management step, the number of times of performing the coating step and the solidification film forming step is counted and managed to be 1 or more and 5 or less, whereby the average film thickness is managed to be 0.4 μm or more and 3.0 μm or less, which is characterized in that.

[0032] According to the third invention, similar to the second invention, the oil-based ink is an oil-based ink containing ethanol at a ratio of 50% by weight or more and 90% by weight or less. Therefore, the viscosity of the oil-based ink is low and it is easy to manage the average film thickness, and the coating film layer can be quickly cured and dried.

[0033] Furthermore, by limiting the number of times of applying the oily ink (hereinafter simply referred to as the number of applications) to at most 5 times, the average film thickness of the consolidated film is controlled to 3.0 μm or less. As a result, the consolidated film is thinly controlled, the total amount of ethanol volatilized in the consolidated film forming process is small, and the amount of the release agent used in the release process of the consolidated film can also be reduced, making it easier to improve the working environment.

[0034] The method for manufacturing a partially plated product according to the fourth invention of the present invention is the first invention, and further includes a second management step of identifying the application range of the oily ink. The second management step is included in any period after the application step and before the start of the plating process. The application step is a step of applying the oily ink containing a coloring agent as a sub-component. In the second management step, the application range of the oily ink is identified based on the coloring state of the coating film layer or the consolidated film.

[0035] According to the fourth invention, the range where the oily ink is applied can be identified based on the coloring state of the coating film layer or the consolidated film. As a result, the presence or absence of uncoated masking agent can be easily and surely identified, improving workability and increasing the production efficiency of the partially plated product. The color of the coloring agent is not limited, but black, blue, red, etc., which are also easy to visually recognize when applied to a metal plating base material, are suitable.

[0036] The method for manufacturing a partially plated product according to the fifth invention of the present invention is the first to fourth inventions, and further includes a fifth step of peeling the consolidated film. The fifth step is characterized by consisting only of a step of immersing the partially plated product on which the plating layer is formed in a release liquid composed of ethanol having a concentration of 90% by volume or more and performing ultrasonic cleaning.

[0037] According to the fifth invention, the release liquid for the solidified film is an ethanol solution that is safe for the human body, and the concentration of ethanol contained in the release liquid is 90% by volume or more. Thereby, even in the process of peeling the solidified film, the working environment of people can be improved, and the solidified film can be peeled off only by immersion in the ultrasonic cleaning tank, and the wiping work by the operator can be omitted, which has an advantageous effect.

[0038] The sixth invention of the present invention is a partial plating product comprising a metal plating base material, a masking layer, and a plating layer, wherein the masking layer is a solidified film whose main component is rosin resin, and is provided in a state of being exposed on a selected part of the surface of the plating base material, the plating layer is composed of a nickel plating layer or a copper plating layer, and is provided only on the remaining part of the surface of the plating base material excluding the part provided with the solidified film, and the average film thickness of the solidified film is 0.4 μm or more and 3.0 μm or less.

[0039] According to the sixth invention, the masking layer is a solidified film containing rosin resin as a main component. Since rosin resin is cured and dried by the volatilization of ethanol which is a solvent, the solidified film does not contain a photoinitiator unlike an ultraviolet curable resin paint, and does not contain a resin cured by heat unlike a heat curable resin paint.

[0040] Since the average film thickness of the solidified film is 0.4 μm or more, pinholes do not occur and defective products are not generated. The upper limit value of the average film thickness is not limited, but it is preferably 5.0 μm or less because the amount of oily ink used can be reduced. In addition, since rosin resin is easily dissolved even in ethanol which is safe for the human body, a thin solidified film is easy to peel off and remove. Thereby, it has an advantageous effect not found in the prior art of being able to provide a partial plating product that does not deteriorate the working environment of people.

[0041] The partial plating product of the seventh invention of the present invention is the sixth invention, characterized in that the plating base material is a mechanical part, and the solidified film is provided on a plurality of surfaces of the mechanical part.

[0042] According to the seventh invention, the plating base material is a machine part that is a three-dimensional object, and a solidified film that is a masking layer is provided on a plurality of surfaces of the machine part. The type of the machine part is not limited, and for example, it may be a gear, a plug, a piston, or the like. Further, the average film thickness of the solidified film is set to 3.0 μm or less, which makes it easy to control the film thickness by the number of times of applying the oil-based ink. Thereby, even in the product in which the coating film layer is formed on a plurality of surfaces of the machine part, it is not necessary to pay attention to dripping and peeling of the coating film layer during the drying period, and the workability is high, and a partial plating product in which the solidified film is easily peeled off can be provided.

[0043] The partial plating product of the eighth invention of the present invention is the sixth or seventh invention, and is characterized in that the solidified film contains a coloring agent as a sub-component. According to the eighth invention, since the solidified film is colored, it is easy to identify the range where the solidified film is formed. Thereby, it is possible to easily find out whether there is a masking defect in the plating base material, and the quality control of the partial plating product is easy.

[0044] The ratio of the coloring agent contained in the solidified film is not limited, but since it is sufficient if the masking range can be visually recognized, the content ratio may be lower than that of a general oil-based marking pen. For example, if the coloring agent is set at a ratio of 5% by weight or more and 40% by weight or less with respect to the weight of the rosin resin forming the solidified film, the main component of the solidified film component becomes rosin resin, and even if the film thickness of the solidified film is thin, pinholes are less likely to occur, and a solidified film that is easy to visually recognize can be obtained.

Effects of the Invention

[0045] · According to the first invention of the present invention, compared with the conventional resin coating for plating, the curing and drying of the coating film layer are remarkably fast, the production efficiency of the partial plating product can be increased, and it is difficult to cause health damage to the operator. Therefore, there is an advantageous effect not found in the prior art that the working environment can be improved. · According to the second invention of the present invention, heating and ultraviolet irradiation are not required for curing and drying the coating film layer, and the production efficiency of the partial plating product can be increased.

[0046] · According to the third invention of the present invention, the solidified film can be thinly controlled, the total amount of ethanol volatilized in the solidified film forming step can be reduced, and the amount of the release agent used in the solidified film peeling step can also be reduced, making it easier to improve the working environment. · According to the fourth invention of the present invention, the presence or absence of the masking agent residue can be easily and surely identified, thereby improving workability and increasing the production efficiency of the partial plating product. · According to the fifth invention of the present invention, even in the solidified film peeling step, the working environment of people can be improved, and the solidified film can be peeled off only by immersion in the ultrasonic cleaning tank, and the wiping work by the operator can also be omitted, showing an advantageous effect.

[0047] · According to the sixth invention of the present invention, there is an advantageous effect not found in the prior art that a partial plating product that does not deteriorate the working environment of people can be provided. · According to the seventh invention of the present invention, even in a product in which a coating film layer is formed on a plurality of surfaces of a mechanical part, there is no need to pay attention to liquid dripping and peeling of the coating film layer during the drying period, and the workability is high, and a partial plating product with easy peeling of the solidified film can be provided. · According to the eighth invention of the present invention, it is possible to easily detect whether there is a masking defect in the plating base material, and the quality control of the partial plating product is easy.

Brief Description of the Drawings

[0048]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0049] In manufacturing a partial plating product, an oil-based ink mainly composed of rosin resin and ethanol is applied to a plating base material to form a coating film layer, and only ethanol is volatilized from the coating film layer to form a solidified film mainly composed of rosin resin. Further, by plating treatment using an acidic bath that does not dissolve the solidified film, a plating layer is formed only on the remaining part where the solidified film of the plating base material is not formed.

Example

[0050] In Example 1, a partial plating product and its manufacturing method will be described with reference to FIGS. 1 to 5. FIG. 1 shows a test photograph when an oil-based ink resistant to an acidic bath is selected using an oil-based marking pen currently on the market. FIG. 1(A) shows a photograph of the oil-based ink applied to a copper plate, and FIG. 1(B) shows a photograph after electroless nickel plating treatment using an acidic bath.

[0051] FIG. 2 shows a photograph of the film thickness of the solidified film observed with an electron microscope. FIG. 3 shows a manufacturing process diagram of the partial plating product. FIG. 4 shows an explanatory diagram of a cross-section of the partial plating product corresponding to the manufacturing process diagram of FIG. 3. FIG. 5 shows photographs of partial plating products manufactured by three types of plating treatments.

[0052] (Selection test of oil-based ink) First, the selection test of the oil-based ink will be described with reference to FIG. 1 and Table 1. In the selection test, 10 types of oil-based marking pens provided by 9 companies were used and applied to a copper plate serving as a plating base material so as to draw a straight line to form a coating film layer (see FIG. 1(A)). Then, after all the coating film layers were cured and dried to form a solidified film, electroless nickel plating treatment was carried out to evaluate the dissolution state of the oil-based ink (see FIG. 1(B)).

[0053] Here, two sets of test pieces with a coating film layer formed are prepared. To make it easier to compare the state of the oil-based ink before and after the plating process, for one of them, the state with a consolidated film formed is left as it is (see Fig. 1(A)), and only the other one is subjected to the plating process (see Fig. 1(B)). In addition, to prevent misreading of the test results, numbers corresponding to each ink shown in Table 1 are drawn on the copper plate with Ink 1 (rosin resin) which was confirmed by a preliminary test not to dissolve in an acidic solution.

[0054] The test location is within the plating factory of the applicant. The conditions for applying the oil-based ink and its curing and drying were carried out by adjusting the temperature of the plating test chamber to about 25°C to make it a normal temperature environment. The coating film layer formed by each oil-based ink was cured and dried within 1 minute, forming a consolidated film. The time required for the curing and drying of each coating film layer was confirmed by applying it to the copper plate in advance and then rubbing the oil-based ink with a finger to ensure that it did not adhere.

[0055] The bath composition per liter of the electroless nickel plating bath was nickel sulfate: about 20 g / L to 25 g / L, sodium hypophosphite as a reducing agent: about 25 g / L to 30 g / L, sodium hydroxide as a pH adjuster: about 1.6 g / L, lactic acid as a complexing agent: about 27 g / L, propionic acid as an accelerator: about 2 g / L, and a sulfur compound as a stabilizer: about 2 mg / L.

[0056] The plating bath conditions were adjusted with the bath temperature at about 90°C and the pH at about 4.0 to 5.0, and air was fed into the plating solution for stirring. Here, the plating bath time was set to about 60 minutes so that the film thickness of the electroless nickel plating layer would be about 5 μm. In addition, a known colloidal solution of palladium was applied to a part of the copper plate to form a catalyst 40 (see Fig. 4) which is the starting point for the formation of the electroless nickel plating layer.

[0057] Next, the ten types of oil-based marking pens will be specifically described. For Ink 1 to Ink 9, black oil-based marking pens were used, and for Ink 10, a blue oil-based marking pen was used. Although only Ink 1 had the resin component disclosed in the safety data sheet, for the comparative examples of Ink 2 to Ink 10, it was found that part or substantially all of the solidified film dissolved and could not be used as a masking agent, so detailed component analysis was omitted.

[0058] Ink 1 is the black color of "Twin Marker" provided by Tombow Pencil Co., Ltd., and the main component as the resin forming the solidified film is rosin resin. Ink 2 is the black color of "Macky (registered trademark)" provided by Zebra Co., Ltd. Ink 3 is the black color of "Magic Ink (registered trademark)" provided by Teranishi Chemical Industry Co., Ltd. Ink 4 is the black color of "Oil-based Marker" provided by Pilot Corporation. Ink 5 is the black color of "Oil-based Marker" provided by Pentel Co., Ltd.

[0059] Ink 6 is the black color of "Name Pen" provided by Sakura Kuretake Co., Ltd. Ink 7 is the black color of "Artline (registered trademark)" provided by Shachihata Inc. Ink 8 is the black color of "Oil-based Marker" provided by Kenz Co., Ltd. Ink 9 is the black color of "Oil-based Marker" provided by Askul Corporation. Ink 10 is the blue color of "Twin Marker" provided by Tombow Pencil Co., Ltd.

[0060] [Table 1] TIFF0007699365000002.tif75158

[0061] (Evaluation of the state of the solidified film after plating treatment) For Ink 2 and Inks 4 to 10, as shown in the photograph of Fig. 1(B) and Table 1, it was confirmed that part or substantially the whole of the solidified film dissolved in the electroless nickel plating solution and thus did not function as a masking agent. Exceptionally for Ink 3, although substantially the whole of the solidified film had dissolved, there were also parts where the plating base material was exposed. However, depending on the plating time, it is presumed that electroless nickel plating will be deposited on this exposed part, so it is not suitable as a masking agent. On the other hand, only the solidified film mainly composed of rosin resin formed by Ink 1 gave good results with no dissolution part occurring at all.

[0062] Hereinafter, the applicant is conducting tests and plating processes using an oil-based ink (hereinafter referred to as this oil-based ink) in which rosin resin and ethanol are mixed. This oil-based ink is prepared by mixing rosin resin manufactured by Hayashi Pure Chemical Industries, Ltd. and absolute ethanol (concentration 99.5% by volume) manufactured by Daishin Chemical Co., Ltd. so that the content ratio of absolute ethanol is 50% by weight or more and 90% by weight or less with respect to the total weight of this oil-based ink.

[0063] When a coloring agent is mixed as a sub-component into this oil-based ink, if the coloring agent is mixed at a ratio of 5% to 40% with respect to the total weight of the rosin resin, the formation range of the solidified film is easy to visually recognize, and even if the solidified film is thin with rosin resin being the main component of the solidified film components, pinholes are less likely to occur in the solidified film. The material of the coloring agent may be a coloring agent soluble in ethanol, for example, a known liquid alcohol dye, but is not limited thereto, and may be a pigment or the like. In addition, as the color of the coloring agent, it is advisable to select black, blue, red, etc. that are easy to visually recognize according to the base color of the plating base material.

[0064] (Film Thickness Control Test) In the film thickness control test, this oil-based ink mixed to contain 70% by weight of absolute ethanol was applied to a copper plate, and the film thickness of the solidified film was imaged with an electron microscope to test how the film thickness of the solidified film changes depending on the number of overcoats. The application to the copper plate was carried out by filling a felt pen with a replaceable core and ink with this oil-based ink.

[0065] FIG. 2 shows the film thickness in three cases: the film thickness when applied once (FIG. 2(A)), the film thickness when applied three times in succession (FIG. 2(B)), and the film thickness when applied five times in succession (FIG. 2(C)). Also, for each number of applications, the film thickness at the thinnest part of the consolidated film (branch number 1), the film thickness at an average part (branch number 2), and the film thickness at the thickest part (branch number 3) are shown side by side.

[0066] [Table 2] TIFF0007699365000003.tif29146

[0067] (Evaluation of Film Thickness Management Test) As shown in Table 2, for the part where the film thickness of the consolidated film is average (hereinafter referred to as the average film thickness), the result was that the average film thickness increased in direct proportion to the number of applications. The same was true for the thick part of the consolidated film. On the other hand, for the thin part of the consolidated film, when the number of overcoats was 3, it increased almost in direct proportion to the number of applications, whereas when the number of overcoats was 5, the film thickness became thinner compared to 3 times.

[0068] According to this test result, it was found that even if overcoating is performed 5 times or more, not only does the work become complicated, but it may also be difficult to manage the average film thickness. Also, although it will be described in detail later together with FIG. 5, even when the number of applications is 1, no masking defect has occurred. Therefore, in the present invention, even for a plating base material such as a mechanical part where the number of overcoats tends to be large, by counting and managing the number of applications up to 5 times, the average film thickness of the consolidated film is formed in the range of 0.4 μm or more and 3.0 μm or less, so as to achieve quality stabilization of the consolidated film and ease of work.

[0069] Note that, since the data becomes complicated, the electron micrograph and the table are omitted. When the proportion of ethanol was 80% by weight, the average film thickness of the consolidated film could be controlled to at least 0.40 μm or more by counting and controlling the number of coating times to 2 or more. Similarly, when the proportion of ethanol was 90% by weight, the average film thickness of the consolidated film could be controlled to at least 0.40 μm or more by counting and controlling the number of coating times to 3 or more.

[0070] (Hardening and Drying Test of Coating Film Layer) In the hardening and drying test of the coating film layer, the time required for the hardening and drying of this oil-based ink was verified by rubbing the coating film layer with a fingertip every predetermined time to check whether the ink adhered to the finger. In this test, the ethanol content ratio in this oil-based ink was 70% by weight, and the number of coating times on the metal plate was changed to 1, 3, and 5 times to compare the hardening and drying times of the coating film layer. The overcoating of the oil-based ink was carried out before the lower coating film layer hardened and dried. In addition, a black liquid alcohol dye was added to this oil-based ink to make it easier to confirm adhesion to the finger.

[0071] [Table 3] TIFF0007699365000004.tif29146

[0072] When the number of coating times was 1, after 15 seconds had elapsed since coating, even when the coating film layer was repeatedly rubbed with a fingertip, the oil-based ink did not adhere to the fingertip. Therefore, based on 15 seconds later, the hardened state was verified by rubbing the overcoated coating film layer at 5-second intervals. As a result, it was confirmed that a consolidated film was formed 20 seconds later in the case of 3 overcoatings and 30 seconds later even in the case of 5 overcoatings. From this test result, according to this oil-based ink, a significant reduction in time is expected in the manufacture of partial plating products compared to conventional resin coatings for plating that require several hours for hardening and drying.

[0073] Next, the manufacturing process of the partial plating product 1 will be described with reference to the flowchart of the manufacturing process in FIG. 3 and the explanatory diagrams at each process stage of the partial plating product in FIG. 4. In FIG. 3, for the main processes (from S100 to S500), the frames are shown with solid lines, and for the optional processes (S10 and S20), the frames are shown with dashed lines.

[0074] FIG. 4(A) shows the plating base material 10 before the degreasing process. At this time, an oil film layer 11 remains on the surface of the plating base material 10. FIG. 4(B) shows the coating process of applying the oil-based ink to the plating base material 10 from which the oil film layer 11 has been removed by degreasing to form the coating layer 20. FIG. 4(C) shows the solidification film forming process in which ethanol volatilizes from the coating layer to form the solidification film 30. FIGS. 4(D) and 4(E) show the plating process of depositing the plating layer 50 by attaching the palladium colloid solution as the catalyst 40 to the plating base material and then immersing it in the electroless nickel plating solution. FIG. 4(F) shows the cleaning process of cleaning the solidification film. Here, a specific example in which the plating base material 10 is a copper plate will be described.

[0075] In step 100, the degreasing process, which is the first process, is carried out to remove the oil film layer on the surface of the copper plate by known alkaline degreasing or electrolytic degreasing (S100). In step 200, the coating process, which is the second process, is carried out to apply the oil-based ink to the surface of the degreased copper plate to form the coating layer 20 (S200). In step 300, the solidification film forming process, which is the third process, is carried out (S300). Here, in a normal temperature environment, it is only necessary to let it stand for about 30 seconds until ethanol volatilizes from the coating layer 20 and the solidification film 30 is formed.

[0076] When the second and third processes are carried out only once, it proceeds to step 20 (S20). On the other hand, when repeating a plurality of times, the number of overcoating times of the oil-based ink is counted as the first management process and controlled within 5 times (S10). In step 20, the range where the solidification film 30 is formed is identified from its coloring state (S20). The identification of the coloring state may be by visual inspection by an operator, but of course, it may also be by identification using an inspection camera.

[0077] When the solidification film is formed within an appropriate range, in the plating process which is the fourth step, electroless nickel plating which is an acidic bath is performed (S400). Even when the formation range of the solidification film is inappropriate, the process returns to the first control step (S10), and the present oil-based ink is reapplied while the number of overcoating times is counted and managed. The bath composition and the like of the plating process will be described later together with FIG. 5.

[0078] After the completion of the plating process, in the cleaning process which is the fifth step, the solidification film is cleaned (S500). In the cleaning process, the plated base material 10 after the plating process is immersed in an ethanol solution generating ultrasonic vibration to peel off the solidification film. The ultrasonic vibration may be generated by immersing a known ultrasonic generator in the storage tank of the ethanol solution. After ultrasonic cleaning, the ethanol solution adhering to the surface of the partially plated product 1 is removed by water washing or the like. The concentration of the ethanol solution will be described later together with Table 4.

[0079] Here, a detailed description of the plating process will be given with reference to FIG. 5. FIG. 5(A) shows a photograph of the partially plated product 1 obtained by performing electroless nickel plating using a copper plate as the plated base material. FIG. 5(B) shows a photograph of the partially plated product 2 obtained by performing electro nickel plating using a brass plate as the plated base material. FIG. 5(C) shows a photograph of the partially plated product 3 obtained by performing electro copper plating using a brass plate as the plated base material. In the partially plated product 1, the details of the plating process are written with a glass rod, and in the partially plated products 2 and 3, they are written with a felt pen. In any case, a clip is attached to the right end of the metal plate, and since the plating process is carried out by suspending the metal plate so that a part of the metal plate protrudes from the plating solution, a plating layer is not attached to a part on the right side of the metal plate.

[0080] (Electroless Nickel Plating Process) Regarding the bath composition of electroless nickel plating, etc., since it has been described in the selection test of the oil-based ink, the description is omitted here. Since the surface hardness of the electroless nickel plating layer can be increased by heating, in the case of plated products for parts that require high strength such as sliding parts, a heating process may be included as a post-treatment. Note that the electroless nickel plating process is not limited to nickel-phosphorus plating, and may be electroless nickel plating using an acidic bath such as known nickel-boron plating or nickel-tungsten-phosphorus plating.

[0081] (Electroplated nickel plating process) The electroplated nickel plating process using an acidic bath may be a Watts bath, which is a known acidic bath. As the bath composition of the electroplated nickel plating solution, for example, per liter of the nickel plating aqueous solution, nickel sulfate: 250 g / L, nickel chloride: 45 g / L, boric acid: 40 g / L. Also, as the plating conditions, the bath temperature is from 40°C to 55°C, the pH is from 3.5 to 4.5, and the current density is from 2 A / dm 2 to 10 A / dm 2 is sufficient. The plating bath time may be adjusted according to the film thickness of the electroplated nickel plating layer and is not particularly limited.

[0082] Note that in the case of electroplating, prior to the electroplating bath, an activation treatment may be performed to immerse the plating base material in an acidic solution to activate the portion where the solidified film is not formed. The acidic solution used for activation may be, for example, when the plating base material is made of copper, a solution obtained by adding water to a stock solution of sulfuric acid containing 98% sulfuric acid by weight ratio so that the ratio of the stock solution of sulfuric acid to water is 1:9 by volume ratio. By the activation treatment, the exposed portion of the plating base material is roughened, and the adhesion between the electroplated layer formed on the surface and the plating base material is improved, so that the plating layer is less likely to peel off from the peripheral portion.

[0083] (Electroplated copper plating process) The electrocopper plating treatment using an acidic bath may be a known copper sulfate bath. As the bath composition of the electrocopper plating solution, for example, per liter of the aqueous copper plating solution, copper sulfate: about 160 g / L to 220 g / L, concentrated sulfuric acid: about 40 g / L to 80 g / L, chloride ions: about 20 mg / L to 80 mg / L. The plating bath conditions were a bath temperature of about 30 °C, a pH of 1.0 or less, and a current density of about 8 A / dm 2 Here, the concentrated sulfuric acid refers to a sulfuric acid solution containing about 98% of the sulfuric acid component by weight ratio. The plating bath time may be adjusted according to the film thickness of the electrocopper plating layer and is not limited.

[0084] (Evaluation test of cleaning treatment) In the evaluation test of the cleaning treatment, the concentration of the ethanol aqueous solution in which the plated base material was immersed was changed, and the peeling state of the solidified film after performing ultrasonic cleaning for 10 seconds and the peeling state of the solidified film when further wiping work was performed were evaluated. The ethanol aqueous solutions to be tested were six types: ethanol aqueous solutions prepared by mixing absolute ethanol and water to 50% by volume, 60% by volume, 70% by volume, 80% by volume, 90% by volume, and an absolute ethanol solution of 99.5% by volume. The results of the evaluation test are shown in Table 4 below.

[0085] [Table 4] TIFF0007699365000005.tif23164

[0086] When the ethanol concentration was 80% by volume or less, the solidified film could not be completely peeled off only by performing ultrasonic cleaning for 10 seconds, and wiping work was also required. On the other hand, when the ethanol concentration was 90% by volume or more, it was confirmed that the solidified film was completely peeled off within 10 seconds of cleaning time, and the wiping work by the operator could be omitted. Therefore, in the case of mass-produced products such as machine parts, it is preferable to immerse them in an ethanol aqueous solution of 90% by volume or more.

[0087] On the other hand, even when the ethanol concentration was between 50% and 80% by volume, the solidified film could be removed simply by having an operator gently wipe it with a cloth. Therefore, in the case of a partial plating product that assumes a wiping operation process after the masking agent is peeled off, for example, in the case of a decorative article manufactured by multiple partial plating processes, the concentration of the aqueous ethanol solution may be less than 90%.

[0088] (Evaluation Test of Plating Layer) In the evaluation test of the plating layer, after the plating process, the solidified film was washed and removed, and the deposition state of the plating layers of the partial plating products 1, 2, and 3 was evaluated. The objects of the evaluation test are shown in Fig. 5. Specifically, there are three cases: when an electroless nickel plating layer is formed on a copper plate (Fig. 5(A)), when an electro-nickel plating layer is formed on a brass plate (Fig. 5(B)), and when an electro-copper plating layer is formed on a brass plate (Fig. 5(C)). The results of the evaluation test are shown in Table 5 below. In this evaluation test, this oily ink is used to write the content of the plating process with a glass rod or a felt pen to form a solidified film.

[0089] [Table 5] TIFF0007699365000006.tif29168

[0090] In any of the plating processes, it was confirmed that a plating layer with a clearly distinguishable contour was formed in the part where the solidified film was formed. That is, according to this oily ink, it was confirmed that peeling did not occur even in the case of a thin solidified film without overcoating in the contour part that serves as the starting point of peeling. From this test result, it was confirmed that the partial plating product using this oily ink is equivalent to the partial plating product using the conventional resin coating for plating in terms of the quality of the plating layer.

[0091] As described above, according to this oil-based ink, it is possible to eliminate strong eye irritation and irritating odor like thinner in both the coating process and the peeling process while maintaining the quality of the partial plating product, and it is possible to improve the working environment of people. Furthermore, since each process time is shortened and the workability is improved, the burden on the operator can be reduced.

[0092] (Others) · In this embodiment, the plating process for depositing a copper plating layer and the plating process for depositing a nickel plating layer were exemplified and described. However, as long as it is a plating process using an acidic bath that does not dissolve the rosin resin, the type of plating process is not limited. For example, it may be a zinc plating process using a known zinc chloride bath, a gold plating process using an acidic bath (potassium gold cyanide), a silver plating process using a non-cyanide silver plating bath, etc. · The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The technical scope of the present invention is not limited to the above description but is indicated by the scope of the claims, and it is intended that all modifications within the meaning and scope equivalent to the scope of the claims are included.

Explanation of Reference Numerals

[0093] 1, 2, 3... Partial plating product, 10... Plating base material, 11... Oil film layer, 20... Coating film layer, 30... Consolidated film, 40... Catalyst, 50... Plating layer

Claims

1. A method for producing a partial plated product, comprising applying a masking agent to a portion of a surface of a plated base material and forming a plating layer on the remaining portion of the plated base material that is not masked, comprising: The method includes steps 1 to 4 in order, The first step is a degreasing step of degreasing the surface of the plating base material, The second step is a coating step of coating the degreased portion with an oil-based ink containing a resin and a solvent as the masking agent to form a coating layer; The third step is a consolidation film forming step of forming a consolidation film by volatilizing a solvent contained in the coating layer, a fourth step is a plating step in which the plating layer is formed only on the remaining portion on which the consolidated film is not formed, using an acid bath; Furthermore, the coating step is a step of coating an oil-based ink in which the main component of the resin constituting the oil-based ink is a rosin resin and the main component of the solvent is ethanol that dissolves the rosin resin, thereby forming the coating layer, The consolidation film forming step is a step of forming the consolidation film, the main component of which is the rosin resin, to have an average thickness of 0.4 μm or more and 3.0 μm or less. A method for producing a selectively plated product comprising the steps of:

2. the coating step is a step of coating the oil-based ink containing ethanol in a ratio of 50% by weight or more and 90% by weight or less with respect to a total weight of the oil-based ink, In the consolidation film forming step, the ethanol is evaporated within one minute without heating or irradiating the coating layer with ultraviolet light, and the consolidation film is formed. The method for producing a selectively plated product according to claim 1 .

3. A first management step of managing the number of times the oil-based ink is applied repeatedly, In a first management step, the number of times that the coating step and the consolidated film forming step are performed is count-managed to be 1 time or more and 5 times or less, so that the average film thickness is controlled to be 0.4 μm or more and 3.0 μm or less. The method for producing a selectively plated product according to claim 2 .

4. Further, a second management step of identifying the application range of the oil-based ink is included, A second management step is included in any period after the application step and before the start of the plating treatment step, The coating step is a step of coating the oil-based ink containing a colorant as a sub-ingredient, In a second management step, the application range of the oil-based ink is identified based on the colored state of the coating layer or the consolidated film. The method for producing a selectively plated product according to claim 1 .

5. The method further includes a fifth step of peeling off the conjunctival membrane, The fifth step comprises only a step of immersing the partially plated product on which the plating layer is formed in a stripping solution containing ethanol having a concentration of 90% by volume or more and ultrasonically cleaning the product. The method for producing a partially plated product according to any one of claims 1 to 4.

6. A partially plated product comprising a metal plating base material, a masking layer, and a plating layer, the masking layer is a consolidation film whose main component is a rosin resin, and is provided in a state where it is exposed on a selected part of the surface of the plating base material; the plating layer is made of a nickel plating layer or a copper plating layer, and is provided only on the remaining portion of the surface of the plating base material excluding the portion on which the consolidation film is provided, The average thickness of the consolidation film is 0.4 μm or more and 3.0 μm or less. A selectively plated product.

7. The plating base material is a mechanical part, The conjugation film is provided on a plurality of surfaces of the mechanical component.

7. The selectively plated product according to claim 6.

8. The conjunctival membrane contains a coloring agent as a secondary component.

8. The partially plated product according to claim 6 or 7.

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