WO2018003620A1

WO2018003620A1 - Method for producing plated roll and mechanism for preventing adhesion of hydrogen gas for plating

Info

Publication number: WO2018003620A1
Application number: PCT/JP2017/022818
Authority: WO
Inventors: 西脇　宏; 美幸亀川; すみ子大野; 敏一村田; 秀浩吉岡; 縄舟　秀美; 幸彦金谷
Original assignee: テクノロール株式会社; フソー株式会社
Priority date: 2016-07-01
Filing date: 2017-06-21
Publication date: 2018-01-04
Also published as: TW201802266A; JP2018003092A

Abstract

This method for producing a plated roll comprises: a smoothing step of smoothing the surface of a roll base material composed of a cylindrical carbon fiber reinforced plastic; a base plating step of performing metal plating on the roll base material having been subjected to the smoothing step; and a surface plating step of performing trivalent chrome plating on the roll base material having been subjected to the base plating step in a plating solution. The surface plating step comprises a hydrogen removal step of removing hydrogen gas generated on a plated surface being formed.

Description

Method for manufacturing plating coating roll and mechanism for suppressing adhesion of hydrogen gas for plating

Cross-reference of related applications

This application claims priority based on Japanese Patent Application No. 2016-131576, and is incorporated herein by reference.

The present invention relates to a method for producing a plating coating roll and a hydrogen gas adhesion suppressing mechanism for plating.

Conventionally, printing rolls and industrial rolls have been made by plating a surface of a roll base material using a carbon steel pipe or an aluminum pipe.

Carbon steel pipes are widely used as roll base materials because they are excellent in terms of strength, ease of processing, and material cost. However, if a carbon steel pipe is used for a roll used for high-speed rotation, such as a film forming feed roll or an offset printing roll, there is a problem in that vibration or rotation unevenness occurs during rotation because bending is likely due to insufficient rigidity. Had occurred. In particular, if the roll is to be widened in order to meet the demand for widening the workpiece, there is a problem that the deflection generated during the rotation of the roll is further increased as the width increases.

In order to suppress such deflection during high-speed rotation, it is conceivable to increase the rigidity of the roll. In order to increase the rigidity, it is necessary to increase the outer diameter and thickness of the roll, which increases the weight of the roll. As the weight increases, the moment of inertia increases, so that rotation unevenness and vibration are likely to occur during rotation. Thus, it has been difficult to use a carbon steel pipe for the roll base material of the roll for high-speed rotation.

Also, aluminum tubes have been used to reduce the weight of rolls. However, the aluminum tube, like the carbon steel tube, increases the weight of the roll when it is attempted to increase the rigidity of the roll. Therefore, it is also difficult to use the aluminum pipe for the roll base material of the roll for high-speed rotation.

On the other hand, rolls used in the field of film conveyance, papermaking, printing, etc., tend to cause uneven rotation of the roll due to the increase in the conveyance speed of the workpiece, which may cause damage such as scratches and wrinkles on the workpiece. It was. In order to improve productivity, it is necessary to increase the rigidity of the roll, to reduce the deflection, and to reduce the moment of inertia. Thus, a lightweight roll has been demanded.

Therefore, a roll has been proposed in which a carbon fiber reinforced plastic (hereinafter referred to as “CFRP”) having a specific gravity smaller than that of carbon steel or aluminum is used as a roll base material, and the surface of the roll base material is subjected to chromium plating. For example, “gravure plate making roll” described in Patent Document 1 can be mentioned.

By the way, when chromium plating is performed, a large amount of hydrogen gas is generated from the plating surface being formed and adheres to the roll surface being plated. In addition, since the pH of the plating surface increases with the generation of hydrogen gas, plating defects (for example, formation of many pinholes, abnormal plating of powdered chromium oxide adhesion, and streaky irregularities are formed on the plating surface. Etc.) and a high-quality plated surface may not be obtained.

Japanese Unexamined Patent Publication No. 2008-143169

Accordingly, the present invention provides a manufacturing method of a plating coating roll and a plating hydrogen gas adhesion suppression mechanism that uses CFRP as a roll base material and suppresses the occurrence of plating defects to obtain a high-quality plating surface. Is an issue.

The present invention provides a smoothing step for smoothing the surface of a roll base material made of cylindrical carbon fiber reinforced plastic, and a base plating step for performing metal plating in a plating solution on the roll base material that has undergone the smoothing step. And a surface plating step of performing trivalent chromium plating on the roll base material that has undergone the base plating step, and the surface plating step includes a hydrogen removal step of removing hydrogen gas generated on the plating surface being formed. A method for producing a plating coating roll.

Further, in the hydrogen removal step, bubbles are discharged to the plating surface being formed, and the discharged bubbles are raised to the liquid level of the plating solution through the plating surface being formed while taking in the hydrogen gas. To remove the hydrogen gas.

Also, chromium ions can be replenished by dissolving the metal chromium with an acid and washing it and then adding it to the plating solution.

Also, electrolytic nickel plating can be performed in the base plating step.

The present invention also includes a bubble generating block connected to a lower portion of a roll base material made of a cylindrical carbon fiber reinforced plastic, which is set in a vertical direction in a plating bath, and a gas supply mechanism for supplying gas to the bubble generating block And the bubble generating block is provided with a plurality of gas ejection holes for discharging the gas supplied by the gas supply mechanism to the plating surface being formed on the upper surface in a state of being arranged in the plating bath. This is a hydrogen gas adhesion suppression mechanism.

FIG. 1 is a schematic longitudinal sectional view showing a plating bath used in one embodiment of the present invention. FIG. 2 is a schematic plan view showing the plating bath. FIG. 3A shows an example of a plating coating roll in which a defect has occurred. FIG. 3B shows an example of a healthy plated roll. FIG. 4 is a schematic longitudinal sectional view showing a plating bath used in another embodiment of the present invention.

Next, a method for producing the plating coated roll of the present invention will be described with reference to an example. The outline of the present embodiment is as follows. After the CFRP element tube 2 which is a cylindrical roll base material is degreased and subjected to a conductive treatment with a conductive paint, a smoothing process is performed to smooth the surface of the CFRP element tube 2 (smoothness). ), Plating such as nickel plating as the base plating (base plating step), and then coating the surface of the CFRP base tube 2 plated with the base with trivalent chromium plating (surface plating step). And

CFRP has a pitch system and a PAN system, but both can be used.

If there is no problem in the dimensional accuracy and surface roughness of the CFRP tube 2, degreasing is performed. Although degreasing depends on the degree of contamination of the surface of the CFRP base tube 2, it is usually washed with water and solvent after degreasing with a surfactant. Then dry thoroughly.

Next, it is confirmed that the resistivity is less than 100 kΩ · cm, preferably 1 kΩ · cm or less, by energizing the surface of the CFRP raw tube 2 using a tester or the like.

When the surface of the CFRP element tube 2 is not smooth, a conductive treatment is performed by applying a conductive paint to the surface so that the film thickness can be processed as described below. As a method for applying the conductive paint, various methods such as spraying, dipping, and brushing can be used. The conductive component contained in the conductive paint is, for example, a metal-based, oxide-based, carbon-based or ionic-based material, and a metal-based or carbon-based material is preferable. A plurality of the conductive components may be used in combination. The resin component contained in the conductive paint is not particularly limited, but an epoxy-based, urethane-based, or acrylic-based resin having good compatibility with CFRP is preferable. The coating thickness is preferably 1 to 200 μm, more preferably 60 to 100 μm.

After the conductive coating is cured, surface treatment is performed so that the surface roughness is preferably 1.0 s or less, more preferably 0.5 s or less, and even more preferably 0.2 s or less. As the surface processing, processing suitable for the required accuracy of the finished product, such as dry or wet polishing using a grindstone, turning using a cutting tool, paper processing using dry or wet paper, is appropriately selected. Preferred processing is polishing processing and paper processing processing.

The conductivity of the surface processed surface is preferably 10 kΩ · cm or less, more preferably 1 kΩ · cm or less, in a range where the following base plating is possible. If the conductivity is insufficient even by application of the conductive paint, the conductive paint can be applied again.

As a pretreatment for performing base plating on the CFRP element tube 2 after the conductive treatment, alkali degreasing or solvent degreasing is performed, and then water washing and pickling are performed. Preferably, solvent degreasing is performed, followed by washing with water and pickling.

As the base plating, various metal plating such as nickel plating, copper plating, and iron plating are possible. Nickel plating is preferred, and as this nickel plating, electrolytic nickel plating or electroless nickel plating is possible. Of these, electrolytic nickel plating has a longer bath life than electroless nickel plating, and is easier to dispose of the plating solution than electroless nickel plating. From this point, it is preferable because there is a merit that the surface processing after plating is unnecessary.

For example, the electrolytic nickel plating can be applied to a CFRP base tube 2 after conducting a conductive treatment in a plating bath using a plating solution of nickel sulfate 240 to 300 g / L, nickel chloride 45 to 50 g / L and boric acid 30 to 40 g / L. Is set in the vertical direction, and plating is performed with a plating thickness of 20 to 50 μm under plating conditions of a current density of 2 to 8 A / dm ² .

After surface plating, surface treatment is performed if necessary, and then trivalent chromium plating is performed after alkaline degreasing, water washing, acid washing, water washing and drying.

For example, trivalent chromium plating can be performed by using chromium chloride or chromium sulfate as a chromium source at 80 to 110 g / L, formate or malate as a complexing agent at 10 to 80 g / L, and boric acid as a pH buffer. In a chromium plating bath 1 using a plating solution 12 prepared by adjusting ammonium chloride, potassium nitrate, atrium sulfate, etc. as a conductive agent in a range of 50-150 g / L and adding a small amount of a surfactant, electrolytic nickel The plated CFRP tube 2 is set in the vertical direction and plated with a plating thickness of 20 to 100 μm under a plating condition of a current density of 3 to 10 A / dm ² .

Here, in trivalent chromium plating, it is necessary to use insoluble anodes such as platinum, graphite, and oxide electrodes. In this case, chromium ions (Cr ³⁺ ions) in the plating solution are consumed and reduced with the progress of plating, so that it is necessary to supply chromium ions. Incidentally, for example, Japanese Patent Application Laid-Open No. 2006-249518 describes that chromium ions are replenished with chromium hydroxide. However, since the described chromium hydroxide is in a water-containing gel form, and it is difficult to separate the solid and liquid, it is difficult to clean the surface. Therefore, when this water-containing gel-like chromium hydroxide is put into the plating solution, it is not washed. Therefore, there is a drawback that the plating solution contains a large amount of impurities. In addition, since the hydrous gel-like chromium hydroxide contains a large amount of water, dehydration is required after the precipitation of chromium hydroxide. In this dehydration and drying process, the chromium hydroxide has a corundum structure and is difficult to dissolve in the plating solution. Therefore, in this embodiment, chromium ions are replenished by the following method.

In this embodiment, in order to replenish chromium ions consumed by electrolytic deposition in a trivalent chromium plating bath, for example, the surface of metallic chromium that is granular is partially dissolved with an acid (specifically hydrochloric acid or sulfuric acid). Then, the oxide film on the surface is dissolved, and then the oxide film is washed with an acid (specifically sulfuric acid) to remove the dissolved oxide film from the metallic chromium. Then, clean metal chromium after the treatment is added to the plating solution 12 to replenish the plating solution 12 with chromium ions. As a specific example, the chromium ion replenishment method is as follows. Metal chromium is added to 20% hydrochloric acid or 20% sulfuric acid heated to 80 ° C., and when bubbles are generated, the metal chromium is taken out and washed with 2% sulfuric acid. The trivalent chromium plating bath 1 is charged. Thereby, since the chromium metal from which the oxide film has been removed is dissolved in the plating bath 1, chromium ions can be replenished promptly without mixing impurities.

Hexavalent chromium plating that has been widely used as chromium plating is excellent in physical properties, productivity, and cost of the plating film. However, since the main component of the plating solution is Cr ⁶⁺ ions, there are concerns about the impact on health, air pollution, and environmental pollution of workers due to mist containing Cr ⁶⁺ ions during manufacturing. The development of was awaited. Therefore, in this example, trivalent chromium was used instead of hexavalent chromium.

Plating baths composed of Cr ³⁺ ions (trivalent chromium baths) have been industrially put to practical use only for decorative applications with a small plating thickness (thickness of 2 μm or less) due to increased environmental awareness. However, with a trivalent chromium bath, it is difficult to obtain a thick film with excellent properties (film thickness of 5 μm or more, desirably 20 μm or more), and it has not been put into practical use for industrial purposes other than decoration. This is because the trivalent chromium plating has a problem that streaks and depressions are formed on the plating surface due to a rapid decrease in plating speed with the elapse of the plating time and generation of hydrogen on the cathode side. In order to solve this problem, it is necessary to remove the foam-like hydrogen gas generated on the surface of the roll base material (CFRP base tube 2) that becomes the cathode during the trivalent chromium plating.

Therefore, in this embodiment, a hydrogen removal process is performed. In this hydrogen removal step, in order to remove the hydrogen gas in the chromium plating bath 1 from the surface of the roll base material (CFRP base tube 2), as shown in FIGS. Set in bath 1. The hydrogen gas adhesion suppressing mechanism 4 includes a bubble generation block 41 having a hollow portion, and a gas supply mechanism 42 having a compressor or the like that supplies air to the bubble generation block 41. For example, as shown in FIG. 1, the gas supply mechanism 42 includes a gas supply source 421, an atmospheric pressure adjustment mechanism 422, and an air supply pipe 423. As the gas supply source 421, a compressor or the like is used when air is sent. Moreover, when sending an inert gas (for example, nitrogen gas), the cylinder filled with the inert gas is used. As the atmospheric pressure adjusting mechanism 422, for example, a regulator capable of setting to a specified gas pressure can be used. In addition to the above, a filter for filtering gas can be added to the gas supply mechanism 42.

Here, the cooling mechanism 6 is provided in the plating tank 11. The cooling mechanism 6 includes, for example, a temperature adjusting device 61, a connection unit 62, and a plating bath cooling unit 63. The plating bath cooling unit 63 is provided in the plating tank 11 at a portion that contacts the plating solution 12. For example, the cooling mechanism 6 can be configured to circulate the refrigerant between the temperature adjusting device 61 and the plating bath cooling unit 63 via a connection unit 62 that is a refrigerant pipe. Alternatively, the temperature adjusting device 61 can be electrically connected to the plating bath cooling unit 63 including a cooling element that is cooled by energization via a connection unit 62 that is an electrical wiring. With these configurations, the plating bath cooling unit 63 can cool the plating solution 12.

Here, since the chromium plating in this embodiment is electroplating, the plating solution 12 is heated and the temperature of the plating solution 12 rises as power is supplied to the chromium plating bath 1. In particular, in the case of trivalent chrome plating, the required power is larger than other plating such as hexavalent chrome plating, so the temperature rise of the plating solution 12 is significant. Therefore, by cooling the plating solution 12 by the cooling mechanism 6, it is possible to suppress the temperature rise of the plating solution 12 and perform trivalent chromium plating in a favorable environment.

In addition, the code | symbol 3 in FIG.1 and FIG.2 is an anode which is an electrode which becomes a pair with a cathode. In the chromium plating bath 1 of the present embodiment, the flat plate-like anodes 3 are provided at four locations, but the shape and quantity are not limited to this. In addition, the shape of the plating tank 11 is not restricted to what was illustrated, and can be various shapes. An electric wire 52 a connected to the negative pole of the rectifier 51 is connected to the CFRP base tube 2 that is a cathode. The anode 3 is connected to an electric wire 52 b connected to the positive pole of the rectifier 51 that is the power supply mechanism 5.

The bubble generating block 41 is connected to the lower side of the CFRP element tube 2 subjected to electrolytic nickel plating, and is a substantially disc-shaped part formed with a larger diameter than the CFRP element tube 2. As shown in FIG. 1, the upper surface of the bubble generation block 41 is formed as a flat surface around the connection portion with the CFRP element tube 2, and is formed on a slope 411 that rises from the middle toward the outside. As shown in FIG. 2, a plurality of gas ejection holes 412 are formed on the inclined surface 411 of the bubble generation block 41 in a circular shape, for example. The air supplied to the bubble generation block 41 by the gas supply mechanism is jetted from the gas jet hole 412 to the chromium plating bath 1.

The air ejected from the gas ejection holes 412 becomes granular bubbles B as shown in FIG. At this time, the bubbles B rise to the surface of the plating solution 12 while taking in hydrogen gas generated on the surface of the chromium plating being formed. By the incorporation, the hydrogen gas is prevented from adhering to the surface of the CFRP element tube 2 during the chrome plating, and the adhering hydrogen gas is removed. Further, the plating solution 12 is agitated by the flow of the plating solution 12 accompanying the release of the bubbles B from the bubble generating block 41.

The hydrogen gas adhesion suppressing mechanism 4 can suppress the occurrence of a large number of pinholes as plating proceeds while the hydrogen gas is adhered to the surface of the roll base material (CFRP base tube 2). In addition, since the plating solution 12 is agitated by the air released from the bubble generating block 41 to the chromium plating bath 1, the pH of the plating solution 12 is locally increased by the generation of hydrogen gas, and chromium oxide or chromium hydroxide is generated. It can suppress that chromium compounds, such as a thing, generate | occur | produce on the chromium plating surface in formation, and precipitation of metal chromium is inhibited.

As described above, in this embodiment, by using the hydrogen gas adhesion suppressing mechanism 4, the problems caused by the conventional trivalent chromium plating are solved, and a thick film having excellent properties can be obtained. For this reason, the plating coating roll which does not use harmful hexavalent chromium also in industrial uses other than a decoration came to be manufactured.

According to the present embodiment, a CFRP, which is a material having a specific gravity smaller than that of carbon steel or aluminum, can be used to form a roll having a small runout even if it is rotated. it can. And since the roll is lightened, it can be expected to provide a roll product corresponding to an increase in line speed, an improvement in yield, and a widening.

Also, since the trivalent chrome plating film has higher hardness than the conventionally used hexavalent chrome plating film, the wear resistance of the plating coating roll can be expected to be improved. Further, in hexavalent chromium plating, cracks (microcracks) occurred when the film thickness was large. This micro-crack causes a problem that a fine uneven pattern is formed (transferred) on the film when the work is a precision resin film. In addition, the micro-crack is not cleaned when the roll is stopped or when the work is changed. At this time, there is a possibility that foreign matter, oil or the like enters the micro crack, and rust is generated on the roll or foreign matter or oil is transferred to the workpiece. In contrast, since trivalent chromium plating does not generate cracks, the above-described problems do not occur and the corrosion resistance increases. Further, in the chromium plating bath 1 of this embodiment, trivalent chromium ions can be constantly supplied to the surface of the chromium plating being formed, and the uniformity of the plating thickness due to the generation of hydrogen can be ensured, so that the bath management is simplified and industrial use. Can withstand use in

As mentioned above, according to the manufacturing method of the plating coating roll concerning a present Example, many merits can be enjoyed.

Next, since the inventor of the present invention actually made a prototype of a CFRP roll, the trial production procedure and results will be described below.

In this trial production, a CFRP element tube 2 having a diameter (φ) of 100 mm, a length of 2000 mm, and a wall thickness of 10 mm was used as a roll base material. As the CFRP base tube 2, a pitch-based carbon fiber tube “Carbo Leader 240” manufactured by Mitsubishi Rayon Co., Ltd. was used.

In order to degrease the CFRP element tube 2, it was first washed with a surfactant, washed with water and washed with warm water, and then sufficiently dried. After degreasing, the conductivity of the surface of the CFRP element tube 2 was measured with a tester, and a carbon-based conductive paint was applied to the surface so that the resistivity was 1000 Ω · cm or less. The film thickness of the applied conductive paint was about 60 μm. After the conductive coating was cured, surface processing was performed so that the surface roughness of the entire roll surface was 0.5 s or less.

As described above, the CFRP element tube 2 confirmed to be conductive was added to nickel sulfate 270 g / L, nickel chloride 47.5 g / L, boric acid 35 g / L, saccharin 5 g / L, 1,4-butynediol 0.3 g / An electrolytic nickel plating having an average plating thickness of 0.03 mm was performed as a base plating under a plating condition of a current density of 5 A / dm ² .

After the electrolytic nickel plating was applied, alkaline degreasing, washing with water, pickling, and drying with water were performed without surface treatment. And chromium chloride or chromium sulfate salt as a chromium source 90g / L, complexing agent formate and malate 45g / L, pH buffer boric acid 50g / L, conductive agent ammonium chloride, potassium nitrate, Sodium sulfate is adjusted in the range of 50 to 150 g / L and placed vertically in the chrome plating bath 1 using a plating solution to which a small amount of surfactant is added, and the current density is 6.5 A / dm ² under plating conditions. Then, trivalent chromium plating with an average plating thickness of 0.05 mm was performed.

In order to prevent hydrogen gas generated on the chromium plating surface being formed during trivalent chromium plating, the plating solution on the roll surface is combined with a mechanism for preventing hydrogen gas from adhering to the cathode surface as shown in FIGS. As a mechanism for urging the agitation, a hydrogen gas adhesion suppressing mechanism 4 for releasing hydrogen gas generated from the lower part of the cathode is provided in the plating tank 11.

In the installation of trivalent chrome plating, in the plating tank 11, a cage-shaped unit that allows easy removal of the plated product is provided, and the nickel-plated state that functions as an insoluble anode 3 and cathode during plating. CFRP element tube 2 was set in the vertical direction. At the lower part of the roll, a bubble generating block 41 made of polyvinyl chloride and having a hole for sending air, which constitutes the hydrogen gas adhesion suppressing mechanism 4, was attached. The air bubbles B generated from the bubble generating block 41 are discharged to the chromium plating bath 1, and the bubbles B take in the hydrogen gas generated in the chromium plating bath 1 and pass through the surface of the chromium plating that is being formed. It rises to the liquid level. Thereby, adhesion of hydrogen gas to the roll surface is prevented. Further, as the bubbles B are released from the bubble generation block 41, the plating solution is agitated. As a result, it was possible to prevent problems caused by hydrogen gas (the generated hydrogen gas locally increased the pH of the plating solution (particularly near the surface of the CFRP element tube 2)), and the plating solution could be uniformly stirred. .

The bubble generation block 41 used in the trial production has a diameter of 160 mm, a flat portion thickness of 50 mm, and a slope 411 formed at 45 °. There are 32 gas ejection holes 412 provided in the circumferential direction on the slope 411 of the bubble generation block 41, and each gas ejection hole 412 has a diameter of 0.3 mm. From the gas ejection hole 412, air is ejected at an angle of 45 ° in the radial inward direction with respect to the vertical direction. The pressure of the ejected air was 0.06 MPa.

As described above, the trivalent chromium plating using the hydrogen gas adhesion suppressing mechanism 4 has a high hardness, trivalent chromium plating that is glossy and has no microcracks and is equal to or higher than the hardness of the conventional hexavalent chromium plating. Was able to produce a plating coated roll coated with. Table 1 shows the results of inspection after polishing the surface after chromium plating. The prototype was confirmed to have less deflection than carbon steel pipes and aluminum pipes (diameter: φ) 100 mm, length 2000 mm, wall thickness 10 mm (both without plating coating). Moreover, neither nickel plating nor trivalent chromium plating confirmed that the peeling of the plating film was visually observed and the adhesion was good.

Here, FIG. 3A shows an example of a plating coating roll (defective product) Rb manufactured when the hydrogen gas adhesion suppressing mechanism 4 is not provided in the chromium plating bath 1. The plating coating roll Rb had a glossy finish at the center of the roll surface, but black defective portions X were formed at the upper and lower portions. The defective part X is a part where chromium oxide or chromium hydroxide is abnormally deposited on the surface of the part due to the adhesion of hydrogen gas. The reason why the defective part X can be formed in the upper part and the lower part is that electricity flows intensively in the corner part of the CFRP elementary tube 2 as compared with the central part, and the pH of the plating solution in contact with this part increases.

On the other hand, the plating coating roll (non-defective product) Rg shown in FIG. 3B is a prototype manufactured by the above-mentioned trial manufacture, and a healthy plating film is formed in the entire area of the roll surface. Thus, in the chromium plating bath 1 of the present Example, it has confirmed that the hydrogen gas adhesion suppression mechanism 4 was functioning effectively.

As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the configuration shown in the above embodiment, and various modifications can be made without departing from the gist of the present invention.

For example, as the hydrogen gas adhesion suppressing mechanism 4, in addition to the configuration of the above embodiment, stirring means such as a propeller may be used in combination. In addition, a nozzle can be provided at a portion of the bubble generating block 41 where air is ejected. The nozzle may be a movable nozzle that moves (rotates, etc.) by air pressure, for example. In addition, in order for the bubbles B to rise along the surface of the roll base material (CFRP base tube 2), a flow guide portion (fin or the like) for guiding the bubbles B can be provided in the chromium plating bath 1. Moreover, although the granular bubble B was formed in the said Example, a film-like bubble can also be formed. In the above embodiment, the plurality of gas ejection holes 412 are provided in the circumferential direction of a single circle, but a plurality of gas ejection holes 412 may be provided in the circumferential direction of two or more concentric circles.

In the above embodiment, air is ejected from the bubble generating block 41. However, as long as it does not adversely affect the trivalent chromium plating, a gas other than air, such as an inert gas, is ejected. You can also.

Further, in the above embodiment, the cooling mechanism 6 is provided in the plating tank 11, but in addition to this, a cooling mechanism is provided in the gas supply mechanism 42, and the bubble is generated by cooling the gas by this cooling mechanism. Can also be supplied. By supplying the gas cooled by the gas supply mechanism 42 to the chromium plating bath 1, the temperature rise of the plating solution 12 can be suppressed as in the above embodiment, and trivalent chromium plating can be performed in a favorable environment.

Furthermore, the hydrogen gas adhesion suppressing mechanism 4 is not limited to the configuration in which the bubbles B are discharged to the chrome plating surface being formed as in the above-described embodiment, and for example, a configuration as shown in FIG. 4 can also be adopted. The hydrogen gas adhesion suppressing mechanism 4 in this embodiment includes a gas removal unit 43, a flange unit 44, a connecting rod 45, and a drive unit 46.

The gas removal unit 43 is provided immovably with respect to the plating tank 11. The gas removal unit 43 is located outside the diameter of the CFRP base tube 2 and extends in the vertical direction to a bar-like support unit 431 and a plurality of plates that are fixed to the support unit 431 and spaced in the vertical direction. Part 432. Although not shown, the plate portion 432 has an annular shape in plan view, and the inner peripheral edge 432 a of the plate portion 432 is positioned so as to surround the outer surface of the CFRP element tube 2. In addition, the inner peripheral edge 432a of the plate portion 432 is located slightly apart from the chrome plating surface being formed in the CFRP element tube 2 without being in close contact therewith. Thereby, the plate part 432 is made not to inhibit formation of chromium plating. The material of the plate portion 432 is not limited, but the trivalent chromium plating film may be damaged even if the plate portion 432 touches the surface of the CFRP base tube 2 when the CFRP base tube 2 moves up and down as will be described later. It is preferable that the material is flexible so that it does not exist.

The flange portion 44 includes a lower flange portion 441 that is connected to the lower end portion of the CFRP element tube 2 and an upper flange portion 442 that is connected to the upper end portion of the CFRP element tube 2 when performing chromium plating. In this embodiment, the lower end portion of the lower flange portion 441 and the upper end portion of the upper flange portion 442 have a conical shape with a tapered shape. For this reason, when the CFRP raw tube 2 moves up and down as will be described later, the flange portion 44 that moves up and down together can prevent the plating solution 12 from causing undulations more than necessary, thereby preventing adverse effects on the chromium plating construction. .

The connecting rod 45 is a rod-like body extending in the vertical direction, is connected to the upper flange portion 442, and protrudes above the plating tank 11. The connecting rod 45 is made of a conductive material and is electrically connected to the power supply mechanism 5 together with the anode 3.

The drive unit 46 includes a drive unit main body 461 and a drive rod 462 extending in the horizontal direction from the drive unit main body 461 and reciprocating in the vertical direction as indicated by an arrow M in FIG. The connecting rod 45 is connected to the drive rod 462. The CFRP base tube 2 can be moved up and down in the chromium plating bath 1 by reciprocating the drive rod 462 in the vertical direction.

As the CFRP element tube 2 moves up and down, a flow of the plating solution 12 in the vertical direction is generated on the surface of the CFRP element tube 2. The flow of the plating solution 12 prevents the hydrogen gas from adhering to the surface of the CFRP element tube 2 during the chrome plating, and the hydrogen gas adhering thereto is removed. Further, since the plating solution 12 flows as the CFRP elementary tube 2 moves up and down, the plating solution 12 is agitated particularly near the surface of the CFRP elementary tube 2.

Also in the hydrogen gas adhesion suppressing mechanism 4 of this embodiment, as in the embodiment provided with the bubble generation block 41, a large number of pinholes are generated in the roll base material (CFRP base tube 2), and metal chromium It can suppress effectively that precipitation is inhibited.

In this embodiment, the gas removal unit 43 is provided immovably and the CFRP element tube 2 is moved up and down. However, the present invention is not limited to this, and the CFRP element tube 2 is provided immovably and the gas removal unit 43 is moved up and down. The gas removal unit 43 and the CFRP element tube 2 can be moved up and down together. Furthermore, the CFRP element tube 2 can be rotated not only in the vertical direction but also in the circumferential direction.

Further, the shape of the flange portion 44 is not limited to the shape of this embodiment, and can be various shapes such as a columnar shape. Further, the flange portion 44 is omitted, and the connecting rod 45 is directly connected to the CFRP base tube 2. You can also.

The configuration and operation related to the above embodiment will be described collectively below. In the above embodiment, a smoothing step for smoothing the surface of the roll base material 2 made of a cylindrical carbon fiber reinforced plastic, and a base plating step for performing metal plating on the roll base material 2 that has undergone the smoothing step, The roll base material 2 that has undergone the base plating step has a surface plating step of performing trivalent chromium plating in a plating solution 12, and the surface plating step removes hydrogen gas generated on the plating surface being formed. It is a manufacturing method of a plating coat roll including a hydrogen removal process.

According to this configuration, the surface plating step includes a hydrogen removal step of removing hydrogen gas generated on the plating surface being formed. For this reason, hydrogen gas adheres to the surface of the roll base material 2 during surface plating, and the pH of the plating solution 12 is locally increased (particularly near the surface of the roll base material 2) due to the generation of hydrogen gas. This can be suppressed.

Further, in the hydrogen removal step, bubbles are discharged to the plating surface being formed, and the discharged bubbles are raised to the liquid surface of the plating solution 12 through the plating surface being formed while taking in the hydrogen gas. Thus, hydrogen gas can be removed.

According to this configuration, the released bubbles rise to the surface of the plating solution 12 while taking in hydrogen gas. For this reason, hydrogen gas generated on the plating surface being formed can be efficiently removed from the plating solution 12.

Further, chromium ions can be replenished by dissolving the metal chromium with an acid and washing it and then adding it to the plating solution 12.

According to this configuration, the surface of the metal chromium is partially dissolved with an acid to dissolve the surface oxide film, and then the oxide film is washed with an acid to remove the dissolved oxide film from the metal chromium. be able to. As a result, clean metal chromium from which the oxide film has been removed is dissolved in the plating bath, so that chromium ions can be replenished promptly without introducing impurities.

Also, electrolytic nickel plating can be performed in the base plating step.

According to this configuration, electrolytic nickel plating eliminates the need for surface processing after plating in terms of film thickness uniformity and surface smoothness.

In the above-described embodiment, the bubble generating block 41 connected to the lower part of the roll base material 2 made of a cylindrical carbon fiber reinforced plastic, which is set in the plating bath 1 in the vertical direction, and gas is supplied to the bubble generating block 41. A plurality of gas supply mechanisms 42, wherein the bubble generating block 41 discharges the gas supplied by the gas supply mechanism 42 to the plating surface being formed on the upper surface in a state where the bubble generation block 41 is disposed in the plating bath 1. It is the hydrogen gas adhesion suppression mechanism 4 for plating provided with the gas ejection hole 412 of this.

According to this configuration, the gas (air, inert gas, etc.) released from the gas ejection hole 412 of the bubble generation block 41 to the plating surface being formed removes hydrogen gas generated on the plating surface being formed. For this reason, hydrogen gas adheres to the surface of the roll base material 2 during plating, and the pH of the plating solution 12 increases locally (particularly near the surface of the roll base material) due to the generation of hydrogen gas. Can be suppressed.

In the above embodiment, hydrogen gas adheres to the surface of the roll base material 2 during plating, and the pH of the plating solution 12 increases locally (particularly near the surface of the roll base material) due to the generation of hydrogen gas. This can be suppressed. For this reason, plating defects such as pinholes caused by hydrogen gas are suppressed, and a high-quality plated surface can be obtained.

DESCRIPTION OF SYMBOLS 1 Plating bath, chrome plating bath 11 Plating tank 12 Plating solution 2 Roll base material, CFRP raw tube 3 Anode 4 Hydrogen gas adhesion suppression mechanism 41 Bubble generation block 411 Part of upper surface, slope 412 Gas ejection hole 42 Gas supply mechanism 43 Gas Removal part 44 Flange part 45 Connecting rod 46 Drive part 5 Power supply mechanism 6 Cooling mechanism B Bubble

Claims

A smoothing step of smoothing the surface of a roll base material made of cylindrical carbon fiber reinforced plastic;
A base plating step of performing metal plating on the roll base material that has undergone the smoothing step;
A surface plating step of performing trivalent chromium plating in a plating solution on the roll base material that has undergone the base plating step;
The said surface plating process is a manufacturing method of the plating coating roll including the hydrogen removal process which removes the hydrogen gas which arises on the plating surface in formation.
In the hydrogen removal step, bubbles are released to the plating surface being formed, and the released bubbles are raised to the surface of the plating solution through the plating surface being formed while taking in the hydrogen gas. The manufacturing method of the plating coating roll of Claim 1 which removes.
The manufacturing method of the plating coating roll of Claim 1 or 2 which replenishes chromium ion by throwing into the said plating solution after melt | dissolving and wash | cleaning metal chromium with an acid.
The method for producing a plating coating roll according to any one of claims 1 to 3, wherein electrolytic nickel plating is performed in the base plating step.
A bubble generating block connected to the lower part of a roll base material made of a cylindrical carbon fiber reinforced plastic, which is set in a vertical direction in a plating bath,
A gas supply mechanism for supplying gas to the bubble generating block,
The bubble generating block includes a plurality of gas ejection holes for releasing the gas supplied by the gas supply mechanism to the plating surface being formed on the upper surface in a state where the bubble generation block is disposed in the plating bath. .