JP6752626B2 - Method for manufacturing electropolishing liquid and electropolished metal molded product - Google Patents

Description

The present invention relates to a method for producing a metal molded product in which an electrolytic polishing liquid and a metal molded product are electrochemically polished in the electrolytic polishing liquid.

Electropolishing is a processing method for finishing the surface of various metal molded bodies to a mirror surface, and is generally widely used in the industrial world. Various electropolishing methods for metal molded bodies have been developed so far. For example, metal molded bodies containing iron, chromium, magnesium, aluminum, titanium, etc., which are base metals whose surface is easily oxidized, are used on the surface. Electropolishing tended to be difficult due to the formed oxide film. In particular, electrolytic polishing of a metal molded body made of titanium or a titanium alloy has a remarkable tendency because the oxide film on the surface is difficult to remove (dissolve).

Titanium or titanium alloy has superior properties to other metals such as light weight, high strength, and excellent corrosion resistance. Therefore, titanium or titanium alloys are used in a wide range of fields such as electronic devices such as semiconductor devices, optical devices, chemical devices, and medical materials. In particular, nickel-titanium alloys having shape memory properties and superelastic properties and having an atomic ratio of nickel to titanium of about 1: 1 are being used as medical materials, and are used in orthodontic wires, guide wires, stents, etc. Widely used in medical devices.

The surface of a medical device represented by such a stent is required to be very smooth. If the surface is rough, it can cause inflammation by damaging or excessively stimulating the tissues in the body during or after transplantation into the human body. Therefore, generally, a metal stent such as a metal stent is used. In the post-process of manufacturing medical devices, a process is performed to finish the surface smooth. As a method for processing the surface of such a medical device, an electrolytic polishing method is preferably used.

In electropolishing of metal moldings, due to deterioration due to the use of the electropolishing solution used, or due to the effects of bubbles generated in the electropolishing solution due to long-term electropolishing, temperature changes, ion concentration gradients in the solution, etc. There is a problem that an uneven metal oxide film layer is formed unevenly on a part or the entire surface of the polished surface, resulting in a white and cloudy polished surface.

Electropolishing is performed by immersing the object to be polished in an electrolytic polishing solution with the object to be polished as an anode and antagonizing anode dissolution and anodic oxidation in a well-balanced manner. When used, anodic oxidation tended to predominate and the generation of white cloudy surfaces tended to be more pronounced.

The deterioration due to the use of the electrolytic polishing liquid refers to a state in which the viscous resistance is increased due to the consumption of ions that contribute to the electrolytic polishing ability or the dissolution of the metal component of the object to be polished.

In particular, in a metal molded body containing titanium, the titanium oxide film layer to be formed is difficult to be removed (dissolved) by electrolytic polishing. Therefore, in order to obtain a flat polished surface, electrolysis using an electrolytic polishing solution containing fluoride is used. Many polishing methods have been devised.

For example, Patent Document 1 exemplifies an electrolytic polishing method using an electrolytic polishing solution containing sulfuric acid, hydrofluoric acid, and acetic acid.

Patent Document 2 exemplifies an electrolytic polishing method using an electrolytic polishing solution containing sulfuric acid, ammonium fluoride, and hydroxycarboxylic acid.

However, since the electrolytic polishing solution containing fluoride imposes a burden on health and the environment, an electrolytic polishing solution containing no fluoride has been used.

For example, Patent Document 3 exemplifies an electrolytic polishing method using a fluoride-free electrolytic polishing solution containing methanesulfonic acid and alcandiphosphonic acid.

Special Table 2003-513166 Gazette Special Table 2006-52671 Japanese Unexamined Patent Publication No. 2008-223139

Since the electropolishing methods of Patent Document 1 and Patent Document 2 use an electropolishing solution containing fluoride, there is a problem that they impose a burden on health and the environment.

On the other hand, the electrolytic polishing method of Patent Document 3 is an electrolytic polishing method in which the burden on health and the environment is reduced by using an electrolytic polishing solution containing no fluoride, but the phosphonic acid used is used. Alcandiphosphonic acid (particularly containing little water), which is a type chelating agent, is relatively expensive, and when used in large quantities industrially, it is costly and has a problem in practical use.

In addition, due to the high hygroscopicity of alkyl sulfonic acid and the carry-in of residual water on the surface of the object to be polished, the electrolytic polishing liquid absorbs water during use, so that a sufficient polishing effect cannot be obtained and there is room for improvement. It was. In particular, the reduction of the polishing effect due to moisture absorption has been a remarkable problem in the electrolytic polishing liquid in which a large amount of metal is dissolved by electrolytic polishing.

In order to solve the above problems, the present invention provides an electrolytic polishing liquid and an electrolytic polishing method for a metal molded body, which are excellent in practicality and have excellent durability of the polishing effect of the electrolytic polishing liquid in electrolytic polishing of a metal molded body. There is.

The present inventor has completed the present invention as a result of diligent studies for solving the above problems. That is, the present invention provides the following electrolytic polishing solutions (1) to (21) and a method for producing an electrolytically polished metal molded body.
(1).
An electrolytic polishing solution for electrolytically polishing a metal molded body, which contains an alkyl sulfonic acid and one or more aminocarboxylic acid type chelating agents.
(2).
The electrolytic polishing solution according to (1), wherein the content of the alkyl sulfonic acid is 20% by weight or more and 99.9% by weight or less.
(3).
The electrolytic polishing solution according to (1) or (2), wherein the content of the aminocarboxylic acid type chelating agent is 0.1% by weight or more and 5% by weight or less.
(4).
The electrolytic polishing solution according to any one of (1) to (3), wherein the aminocarboxylic acid type chelating agent is at least one selected from ethylenediaminetetraacetic acid and ethylenediaminetetraacetic acid salt.
(5).
The electrolytic polishing solution according to any one of (1) to (4), which contains a nonionic surfactant.
(6).
The nonionic surfactant is one or more selected from polyoxyethylene alkyl ethers having 1 to 30 molar additions of ethylene oxide and polyoxyethylene alkyl phenyl ethers having 1 to 30 molar additions of ethylene oxide. The electrolytic polishing solution according to (5), which is characterized by being present.
(7).
The electrolytic polishing solution according to (5) or (6), wherein the content of the nonionic surfactant is 0.001% by weight or more and 0.1% by weight or less.
(8).
The electrolytic polishing liquid according to (1) to (7), which contains glycols.
(9).
The electrolytic polishing solution according to (8), wherein the glycols are ethylene glycol.
(10).
The electrolytic polishing solution according to (8) or (9), wherein the content of the glycols is 1% by weight or more and 80% by weight or less.
(11).
A method for producing a metal molded body, which comprises using the electrolytic polishing solution according to any one of (1) to (10) and applying an electrolytic polishing step of applying a voltage for a certain period of time at least once.
(12).
The method for producing a metal molded body according to (11), which comprises a step of mixing an orthoester compound with the electrolytic polishing liquid.
(13).
The orthoester compounds include triisopropyl orthoformate, tributyl orthoacetate, triethyl orthoacetate, triethyl orthoacetate, triethyl orthoacetate, triethyl orthopropionate, triethyl orthovalerate, trimethyl orthoacetate, trimethyl orthobutyrate, orthoacetate. The method for producing a metal molded product according to (12), which comprises at least one selected from trimethyl acid, trimethyl orthoisobutyrate, trimethyl orthopropionate, trimethyl orthoacetate, and tripropyl orthoformate.
(14).
The method for producing a metal molded body according to (12) or (13), wherein the orthoester compound is mixed in an amount of 0.1% by weight or more and 40% by weight or less based on the weight of the electrolytic polishing liquid before mixing. ,
(15).
The method for producing a metal molded body according to any one of (11) to (14), wherein the metal molded body is a metal molded body made of a base metal.
(16).
The method for producing a metal molded body according to (15), wherein the metal molded body is a metal molded body containing at least one selected from iron, chromium, magnesium, aluminum, and titanium.
(17).
The method for producing a metal molded body according to (16), wherein the metal molded body is titanium or a titanium alloy.
(18).
The method for producing a metal molded body according to (17), wherein the metal molded body is a nickel titanium alloy.
(19).
The method for producing a metal molded body according to any one of (11) to (18), wherein the metal molded body is a medical tubular body.
(20).
The method for producing a metal molded body according to (19), wherein the medical tubular body is a stent.
(21).
(20), the method for manufacturing a medical catheter having the stent according to (20).
Regarding.

According to the present invention, it is possible to produce an electrolytic polishing liquid which is excellent in practicality and has excellent durability of the polishing effect of the electrolytic polishing liquid.

It is the schematic which shows the electrolytic polishing apparatus which is one Embodiment of this invention. It is the schematic which shows the electrolytic polishing apparatus which is one Embodiment of this invention. It is a stereomicroscopic image of the stent which concerns on Example 1 of this invention. It is a stereomicroscope image of the wire which concerns on Example 2 of this invention. It is a stereomicroscope image of the wire which concerns on Example 3 of this invention. It is a stereomicroscopic image of the stent which concerns on Example 4 of this invention. It is a stereomicroscopic image of the stent which concerns on Example 7 of this invention. It is a stereomicroscopic image of the stent which concerns on Example 10 of this invention. It is a stereomicroscopic image of the stent which concerns on Example 19 of this invention. It is a stereomicroscopic image of the stent which concerns on Example 20 of this invention. It is a stereomicroscopic image of the stent which concerns on Example 25 of this invention. It is a stereomicroscopic image of the wire which concerns on Example 28 of this invention. It is a stereomicroscopic image of the wire which concerns on Example 29 of this invention. It is a stereomicroscope image of the wire which concerns on Example 30 of this invention. It is a stereomicroscopic image of the stent which concerns on Comparative Example 1 of this invention. It is a stereomicroscopic image of the stent which concerns on Comparative Example 2 of this invention. 3 is a stereomicroscopic image of a stent according to Comparative Example 3 of the present invention. 3D surface image of the stent according to Example 1 of the present invention. 3D surface image of the stent according to Comparative Example 1 of the present invention.

The electrolytic polishing liquid of the present invention is characterized by containing an alkyl sulfonic acid and one or more aminocarboxylic acid type chelating agents. Further, the electrolytic polishing liquid of the present invention can appropriately contain a nonionic surfactant and glycols.

Further, the electropolishing method for a metal molded body of the present invention is characterized by including one or more electropolishing steps of applying a voltage for a certain period of time using the electropolishing solution of the present invention. Further, the electrolytic polishing method of the present invention is for removing water in the electrolytic polishing liquid which lowers the electrolytic polishing effect, or lowers the viscous resistance of the electrolytic polishing liquid, or reduces the surface tension of the solution to reduce the surface tension of the solution on a metal surface. In order to improve the wettability against water, a step of mixing the orthoester compound with the electrolytic polishing liquid can be included.

Hereinafter, the electrolytic polishing liquid and the electrolytic polishing method for the metal molded body according to the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

<Metal injection>
The metal molded body of the object to be polished in the present invention is not particularly limited as long as it is a metal that can be electropolished by the electrolytic polishing solution or the electrolytic polishing method of the present invention, but a metal molded body made of a base metal whose surface is easily oxidized is preferably used. Be done. As the metal molded body made of a base metal, for example, a metal molded body containing at least one selected from iron, chromium, magnesium, aluminum, and titanium is preferably used. The base metal referred to here is a metal that has a higher ionization tendency than hydrogen chemically. In particular, a metal molded body containing titanium or a titanium alloy that forms a strong oxide film on the surface (hereinafter, may be referred to as a titanium-based metal molded body) can be particularly preferably used. The titanium-based metal molded body includes a molded body made of pure titanium, and a molded body made of titanium and at least one other metal.

The titanium-based metal molded body is preferably one selected from pure titanium, titanium alloys, and titanium-based shape memory alloys.

Specific examples of titanium or titanium alloys include pure titanium; Ti-15Mo, Ti-5Al-5Sn, Ti-6Al-4V, ELI, Ti-6Al-4V, Ti-6Al-7Nb, Ti-15Mo-5Zr. , Ti-5Al-3Mo-4Zr, Ti-13Nb-13Ta, Ti-12Mo-6Zr-2Fe, Ti-15Zr-4Nb-2Ta-0.2Pd, Ti-35.3Nb-5.1Ta-4.6Zr, Ti -29Nb-13Ta-4.6Zr, Ti-15Sn-4Nb-2Ta-0.2Pd, other Ti-rich alloys, etc .; Ni-Ti-based, Ni-Ti-Co-based, Ni-Ti-Fe-based, Ni -Ti-Cr-based, Ni-Ti-Cu-based, Ni-Ti-Cu-Cr-based shape memory alloys, and various other shape memory alloys containing Ni and Ti as main components are mentioned, and in particular, nickel is contained. A nickel-titanium alloy is preferable, and a nickel-titanium alloy having an atomic ratio of titanium to nickel of about 1: 1 is more preferable.

The above-mentioned metal molded body made of nickel titanium alloy is particularly preferably used as a medical material, and specific examples thereof include a medical tubular body represented by a stent, an embolic device for treating atrial septal defect, and the like. Examples thereof include an aneurysm embolic coil, a thrombus filter, a guide wire, an orthodontic arch wire, and a cerebral aneurysm wire.

A stent is a mesh-like tubular body that is placed inside the body to prevent restenosis after dilation of a stenosis such as a blood vessel. For medical stents, for example, (a) one linear stent. Coil-shaped type made of metal or polymer material, (b) metal tube cut out by laser, etc., (c) linear member welded by laser, etc., (d) multiple wires There is a type made by weaving a metal.

The stent in the present invention is, for example, a tubular that expands in diameter from a first diameter that is the size to be inserted into the luminal structure of the body to a second diameter in which at least a part of the outer surface of the tubular body contacts the blood vessel wall. The body is mentioned, and in particular, it can be preferably used as a medical tubular body used for plasty of an internal luminal structure such as a blood vessel, a ureter, and a bile duct.

As a material used for a stent, a nickel titanium alloy can be preferably used because it has shape memory properties and superelastic properties and is also excellent in workability. Further, among the nickel titanium alloys, a nickel titanium alloy containing about 50% to about 60% nickel can be preferably used.

As a method for producing a metal stent, a method in which a tubular material is cut out in a mesh shape by a laser and then electropolished can be preferably used.

Electropolishing involves removing the surface oxide film generated by laser processing of the strut part, which is the bent linear part of the stent, or heat treatment after laser processing, and rounding (round shape) the sharp edges of the strut cross section. It is done for the purpose of. Electropolishing is preferably performed as a final finishing step for various purposes such as reducing metal elution, improving fatigue properties, and improving cleanliness.

<Electropolishing solution>
The electrolytic polishing liquid of the present invention is characterized by containing an alkyl sulfonic acid and at least one aminocarboxylic acid type chelating agent.

The alkyl sulfonic acid that can be used in the present invention is not particularly limited as long as it has an electrolytic polishing effect, and a commercially available alkyl sulfonic acid can be preferably used. Examples of commercially available alkyl sulfonic acids include methane sulfonic acid, ethane sulfonic acid, propane sulfonic acid, butane sulfonic acid, pentan sulfonic acid, hexane sulfonic acid, heptane sulfonic acid, octane sulfonic acid and the like. Among them, methanesulfonic acid is preferable because it has high polishing efficiency.

In the present invention, the lower limit of the content of the alkyl sulfonic acid in the electrolytic polishing liquid is preferably 20% by weight or more, more preferably 30% by weight or more, and particularly preferably 40% by weight or more, from the viewpoint of ensuring viscosity.

The upper limit of the content of the alkyl sulfonic acid in the electrolytic polishing solution is preferably 99.9% by weight or less, more preferably 99.5% by weight or less, and particularly preferably 99% by weight or less from the viewpoint of ensuring conductivity. , 98.7% by weight or less is even more preferable.

The pH of the electrolytic polishing solution of the present invention is preferably 2.0 or less, more preferably 1.0 or less, and even more preferably 0.5 or less.

The aminocarboxylic acid type chelating agent in the present invention is a compound having an amino group and a carboxyl group. Usually, it also includes a polyvalent molecule having a plurality of carboxyl groups, in which the carboxyl group is substituted with a hydroxyl group, and the structure of a derivative in which hydrogen of the carboxyl group is substituted with sodium, calcium or the like.

The aminocarboxylic acid type chelating agent coordinates with the metal eluted from the object to be polished by electropolishing to form complex ions, thereby preventing the formation of suspended substances of metal compounds in the electropolishing solution and causing disorder. It has the effect of suppressing and stabilizing the anodic dissolution and maintaining the electrolytic polishing ability.

Specific examples of the aminocarboxylic acid type chelating agent include iminodiacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, nitrilotripropionic acid, ethylenediaminetetraacetic acid, hydroxyethylenediaminetriacetic acid, hexamethylenediaminetetraacetic acid, and diethylenetriamine-5. Acetic acid, triethylenetetraminehexacetic acid, trans-1,2-diaminocyclohexanetetraacetic acid, bis (2-hydroxyethyl) glycine, diaminopropanol tetraacetic acid, ethylenediamine-2-propionic acid, glycol etherdiaminetetraacetic acid, bis (2-) Hydroxybenzyl) ethylenediaminediacetic acid, salts thereof and the like can be mentioned. In particular, ethylenediaminetetraacetic acid or a salt thereof, which is excellent from the viewpoint of cost, is preferably used.

In the present invention, the lower limit of the content of the aminocarboxylic acid type chelating agent is preferably 0.1% by weight or more, more preferably 0.3% by weight or more in the electrolytic polishing liquid from the viewpoint of maintaining the metal coordination effect. It is preferable, and 0.5% by weight or more is particularly preferable.

Further, the upper limit of the content of the aminocarboxylic acid type chelating agent is preferably 5% by weight or less, preferably 3% by weight, because if the metal coordination effect is too strong, the anode dissolution is suppressed too much and the electrolytic polishing effect is hindered. % Or less is more preferable, and 2% by weight or less is particularly preferable.
In the electrolytic polishing solution of the present invention, one type of aminocarboxylic acid type chelating agent may be used, or two or more types may be mixed and used.

The electrolytic polishing liquid of the present invention can further contain a nonionic surfactant. Nonionic surfactants are surfactants that do not exhibit ionicity when dissolved in a liquid, but exhibit surface activity.

The nonionic surfactant improves the wettability of the electrolytic polishing liquid with respect to the object to be polished and promotes the release of the gas generated from the electrode, thereby exhibiting the effect of obtaining a uniform polished surface with less uneven polishing. Further, since the nonionic surfactant is nonionic, it is not easily affected by other components in the electrolytic polishing liquid, has excellent dispersibility, and has little foaming, and is therefore preferably used.

Specific examples of the nonionic surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether and polyoxyethylene lauryl ether, and polyoxyethylene alkyls such as polyoxyethylene nonylphenyl ether and polyoxyethylene octylphenyl ether. Examples thereof include phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene fatty acid amide, and a perfluoroalkyl group-containing ethylene oxide adduct. Preferably, polyoxyethylene alkyl ether or polyoxyethylene alkyl phenyl ether is used. The number of moles of these ethylene oxides added is preferably 1 to 30, more preferably 2 to 15.

In the present invention, the lower limit of the content of the nonionic surfactant is preferably 0.001% by weight or more, more preferably 0.003% by weight or more, and 0.005% by weight or more from the viewpoint of improving wettability. Especially preferable.

Further, the upper limit of the content of the nonionic surfactant is preferably 0.1% by weight or less because excessive foaming in the electrolytic polishing liquid due to the influence of the surfactant hinders the electrolytic polishing effect. It is more preferably 0.05% by weight or less, and particularly preferably 0.02% by weight or less.

In the electrolytic polishing solution of the present invention, one type of nonionic surfactant may be used, or two or more types may be mixed and used.

The electrolytic polishing liquid of the present invention can further contain glycols. Glycos are compounds having a structure in which two carbon atoms of a chain aliphatic hydrocarbon or a cyclic aliphatic hydrocarbon are substituted with one hydroxyl group, and are also called diol compounds.

The glycols have the effect of adjusting the viscosity of the electrolytic polishing liquid to obtain a uniform polished surface with less uneven polishing. On the polar surface of the object to be polished in the electrolytic polishing liquid, metal ions and the electrolytic polishing liquid are entangled to form a mucilage layer, and due to the large electrical resistance of this mucilage layer, the convex portion of the surface of the object to be polished Since the current easily flows, the surface is smoothed. Therefore, it is very important to adjust the viscosity of the electrolytic polishing liquid.

Specific examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-. Examples thereof include butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, and 1,4-cyclohexanediol. In particular, ethylene glycol is preferably used.

In the present invention, the lower limit of the content of glycols is preferably 1% by weight or more, more preferably 5% by weight or more, and particularly preferably 10% by weight or more from the viewpoint of adjusting the viscosity.

Further, the upper limit of the content of glycols is preferably 80% by weight or less, preferably 70% by weight, because if the viscosity is too high, the fluidity is lowered and the conductivity is lowered and the foam breakage is deteriorated, which hinders the electrolytic polishing effect. % Or less is more preferable, and 60% by weight or less is particularly preferable.

Depending on the usage environment, the electrolytic polishing liquid may absorb moisture in the air, or the moisture content of the electrolytic polishing liquid may increase due to the influence of the residual moisture of the object to be polished. In particular, when the water content exceeds 2% by weight, a white cloudy surface is likely to be generated on the polished surface of the titanium-based metal molded body after electrolytic polishing, and further, the surface smoothness tends to be insufficient. is there. The water content of the electrolytic polishing liquid is preferably substantially anhydrous with respect to the total amount of the electrolytic polishing liquid, but is preferably 2% by weight or less at most, and 1 weight by weight. The content is more preferably% or less. The water content of the electrolytic polishing liquid can be measured by a known method, and for example, the Karl Fischer method is exemplified.

Further, it is preferable that the electrolytic polishing liquid of the present invention does not contain fluoride. Examples of the fluoride include sodium fluoride, potassium fluoride, lithium fluoride, ammonium fluoride, hydrogen fluoride and the like. Since the use of a fluoride-containing electrolytic polishing solution involves risks to health and the environment, it is preferable to use a fluoride-free electrolytic polishing solution. The concentration of fluoride in the electrolytic polishing solution of the present invention is preferably 0.5% by weight or less, more preferably 0.1% by weight or less, and even more preferably 0.01% by weight or less.

The content of each component of the electrolytic polishing liquid can be appropriately adjusted according to the type and shape of the metal molded body to be electrolytically polished, the size of the electrolytic polishing area, and the like.

The electrolytic polishing liquid of the present invention is excellent in sustainability of the polishing effect because it is not easily affected by the inhibition of the polishing effect by moisture even if it absorbs moisture by the components constituting the liquid.

<Electropolishing method>
In the electrolytic polishing method of the present invention, the cathode and the anode made of the metal molded body are immersed in the electrolytic polishing liquid of the present invention, and a voltage is applied between both electrodes to polish the surface of the metal molded body. Includes one or more steps.

Depending on the shape of the metal molded body to be electropolished and the polished area, an anode conductive member capable of electrically conducting the electrode and the metal molded body can be used to fix the metal molded body.

FIG. 1 shows an electrolytic polishing apparatus in which an electrode is brought into contact with a metal molded body 14 to be polished to perform electrolytic polishing.

In the electrolytic polishing, the anode conductive member 13 connected to the positive electrode of the power supply 11 by the conductive wire 12a is in contact with the metal molded body 14 in the electrolytic polishing liquid 17 stored in the electrolytic polishing liquid tank 15. Further, the cathode 16 connected to the negative electrode of the power supply 11 by the conductive wire 12b is installed so as to be separated from the metal molded body 14. When a voltage is applied between the anode conductive member 13 and the cathode 16 in such an arrangement state, the metal element on the surface of the metal molded body 14 acting as the anode dissolves in the electrolytic polishing liquid 17. As a result, the metal molded body 14 can be electropolished to have a smooth surface and give gloss.

The material of the anode conductive member 13 can be appropriately selected according to the type of electrolytic polishing liquid used, and is not particularly limited as long as it has sufficient conductivity. For example, stainless steel, titanium, copper, and aluminum. , Platinum, gold and other metals or alloys thereof.

The shape of the anode conductive member 13 can be appropriately selected according to the type and shape of the metal molded body to be used, and is not particularly limited as long as the metal molded body 14 of the object to be polished can be conductively fixed. It may be plate-shaped, wire-shaped, rod-shaped, core-shaped, or clip-shaped as shown in FIG.

The material of the cathode 16 can be appropriately selected according to the type of electrolytic polishing liquid used, and is not particularly limited as long as it has sufficient conductivity. For example, stainless steel, titanium, copper, aluminum, platinum, etc. Examples include metals such as gold and alloys thereof.

The shape of the cathode 16 can be appropriately selected according to the type and shape of the metal molded body to be used, and is not particularly limited as long as the metal molded body 14 can be electropolished. For example, a plate shape, a core shape, a rod shape, or the like. A mesh shape or a punching shape is provided on the cathode 16 in order to increase the surface area of the cathode 16 and to avoid air bubbles, temperature changes and concentration gradients of ions in the liquid generated during electrolytic polishing. It may be formed. Further, it is preferable to make the shape so that the current flows uniformly according to the shape of the product to be polished, and for example, it can be made into a cylindrical shape so as to surround the object to be polished.

Since the electrolytic polishing liquid of the present invention has a high polishing ability, the metal molded body can be uniformly polished without physical polishing, for example, polishing with a polishing pad, a polishing cloth, polishing paper, a grindstone, abrasive grains, a slurry, or the like. Can be polished.

In the electrolytic polishing step of the present invention, a voltage is applied to the metal molded body 14 and the cathode 16 as anodes for a certain period of time by the power supply 11, and the metal molded body 14 can be electrolytically polished to a desired smoothness. Further, in the electrolytic polishing step of the present invention, it is preferable to apply a constant voltage for a certain period of time. When a constant voltage is applied, the current density rapidly increases immediately after the voltage is applied, and then gradually decreases and stabilizes, so that a smooth polished surface can be easily obtained.

The current density in the present invention indicates a range of values measured from the maximum value shown by reaching a desired voltage to the end of electrolytic polishing, and a voltage (current density) is applied. The time is called the electrolytic polishing time.

In the electrolytic polishing step of the electrolytic polishing method of the present invention, the liquid temperature of the electrolytic polishing liquid is preferably 10 ° C. or higher and 80 ° C. or lower, particularly preferably 20 ° C. or higher and 40 ° C. or lower, 25. It is more preferably ° C. or higher and 30 ° C. or lower.

The voltage value in the electrolytic polishing step of the electrolytic polishing method of the present invention is preferably 10 V or more and 45 V or less, and more preferably 15 V or more and 35 V or less.

The current density in the electrolytic polishing process is preferably 40 mA / cm ² or more, and more preferably 50~5000mA / cm ^2.

The lower limit of the electrolytic polishing time to which the voltage of the electrolytic polishing step is applied is preferably 1 second or more, particularly preferably 20 seconds or more, and the upper limit is preferably 60 seconds or less, preferably 40 seconds. Within is particularly preferable.

Electropolishing is preferably performed twice or more in that more uniform electropolishing can be performed and a flat polished surface can be easily obtained. The suitable number of times of electropolishing is not particularly limited as long as a smooth surface can be obtained, but it is preferably repeated 2 to 30 times in terms of more uniform electropolishing.

Further, it is preferable that the metal molded body 14 is once taken out from the electrolytic polishing liquid 17 in each electrolytic polishing step, and the metal molded body 14 is washed with alcohol, water, nitric acid, or a solution obtained by combining them. After repeating several times, it is preferable to immerse in an ultrasonic bath at room temperature for 1 to 30 minutes for washing.

In the electrolytic polishing method of the present invention, in order to remove water contained in the electrolytic polishing liquid, to reduce the viscous resistance of the electrolytic polishing liquid increased by the dissolved component of the metal molded body of the object to be polished, or to reduce the electrolytic polishing liquid. It is preferable to include a step of mixing the orthoester compound with the electrolytic polishing liquid for the purpose of reducing the surface tension of the metal surface and improving the wettability with respect to the metal surface.

The orthoester compound that can be used in the present invention refers to an organic compound having three alkoxy groups on the same carbon. The three alkoxy groups may be of the same type or of different types. Further, the alkyl group of the alkoxy group may be linear, branched, substituted or unsubstituted.

Hydrolysis of 1 mol of the orthoester compound produces 1 mol of the corresponding ester compound and 2 mol of the corresponding alcohol. The orthoester compound is usually a compound that is liquid at room temperature.

The orthoester compound is easily hydrolyzed by reacting with the water content in the electrolytic polishing solution, and changes into a volatile component such as an alcohol compound. As a result, a sufficient dehydration action can be obtained without interfering with the component system effective for electrolytic polishing.

Specific examples of the orthoester compound include, formic acid ester, orthoacetate ester, orthopropionic acid ester, orthobutyric acid ester, diethylphenyl orthoatete, triethyl orthochloroacetate, triethyl orthodichloroacetate, and triisopropyl orthoacetate. Tributyl ortho, triethyl orthoacetate, triethyl orthoacetate, triethyl orthoformate, triethyl orthopropionate, triethyl orthoacetate, trimethyl orthoacetate, trimethyl orthobutyrate, trimethyl orthoacetate, trimethyl orthoisobutyrate, trimethyl orthopropionate, ortho Examples thereof include trimethyl orthoacetate and tripropyl orthoate. Among these, from the viewpoint of availability, triisopropyl orthoate, tributyl orthoate, triethyl orthoacetate, triethyl orthoacetate, triethyl orthoate, triethyl orthopropionate, triethyl orthoacetate, trimethyl orthoacetate, Preferably used are trimethyl orthoacetate, trimethyl orthoformate, trimethyl orthoisobutyrate, trimethyl orthopropionate, trimethyl orthoacetate, tripropyl orthoformate and the like.

In the present invention, the lower limit of the mixing amount of the orthoester compound is preferably 0.1% by weight or more, more preferably 1% by weight or more, and mixed by 5% by weight or more in order to sufficiently remove the water content in the electrolytic polishing liquid. It is particularly preferable to let it.

The upper limit of the mixing amount of the orthoester compound is preferably 40% by weight or less, more preferably 30% by weight or less, and particularly preferably 20% by weight or less, from the viewpoint of not affecting the electrolytic polishing liquid.

As the timing of mixing the orthoester compound, from the viewpoint of performing stable electrolytic polishing, it may be added to the electrolytic polishing liquid in advance and mixed, and from the viewpoint of improving storage stability, it is used to some extent. When the moisture in the environment is absorbed, it may be added to the electrolytic polishing solution and mixed.

In the addition and mixing operation of the orthoester compound according to the present invention, the orthoester compound and the reaction product thereof remaining in the electrolytic polishing solution without being used in the reaction reduce the viscous resistance of the electrolytic polishing solution or increase the surface tension. The effect of making it smaller and improving wettability can be expected.

When removing a part or all of the remaining orthoester compound and the reaction product from the electrolytic polishing solution, it can be removed by heating under normal pressure, reduced pressure, or pressure.

Further, from the viewpoint of improving the dehydration effect, an acid other than the alkyl sulfonic acid can be mixed with the orthoester compound. The acid other than the alkyl sulfonic acid may be any substance as long as it functions as an acid catalyst. For example, sulfuric acid, p-toluene sulfonic acid, benzene sulfonic acid, 2,4-dimethylbenzene sulfonic acid, 10-campar sulfonic acid. Examples thereof include acids and trifluoromethanesulfonic acids, and particularly strong acids containing almost no water can be preferably used.

Further, the step of mixing the orthoester compound may be included a plurality of times before electropolishing or between electropolishing steps.

Since the electrolytic polishing method of the present invention can easily obtain a smooth surface, it can be preferably used for a medical tubular body such as a stent.

Hereinafter, the electrolytic polishing method of the present invention will be described in more detail with reference to FIG. 2 by taking a stent as an example of a metal molded body, but the present invention is not limited thereto.

The electrolytic polishing device shown in FIG. 2 is an electrolytic polishing device for electrolytically polishing a stent 214 or the like. It is mainly composed of a power supply 211, an electrolytic polishing liquid 217, an anode conductive member 213, a cathode 216, and an electrolytic liquid tank 215, and the stent 214 is expanded substantially evenly so as to have a substantially circular shape. It has an anode conductive member 213 that supports the inner surface of 214.

The anode conductive member 213 has four elongated members 21 so as to be in contact with the stent 214 at four electrical contacts 218. Each elongated member 21 extends over the entire length of the stent 214 in the longitudinal direction, and forms four electrical contacts 218 in its cross section. Further, an extension portion 22 extending outward from the apex to which the elongated members 21 are joined is joined. The anode conductive member 213 is electrically conductively connected to the anode connecting portion 23 for fixing the anode conductive member 213 of the main body of the electrolytic polishing apparatus.

In the electropolishing step in the electropolishing method of the present invention, the power supply 211 is operated in the state of FIG. 2, and a voltage is applied between the stent 214 and the cathode 216 to perform electropolishing.

The structure of the anode connection portion 23 is a pin vise structure, and the anode conductive member 213 can be removed from the anode connection portion 23 during the electrolytic polishing step, and the anode conductive member 213 can be cleaned with the stent 214 attached. Further, it is preferable to move the stent 214 in the circumferential direction for each electrolytic polishing step to change the electrical contact 218 between the stent 214 and the elongated member 21 of the anode conductive member 213.

Since the anode rotating portion 24 is provided on the anode connecting portion 23 and the entire anode rotating portion 26 is further provided on the anode support portion 25, the stent 214 and the entire anode support portion 25 are rotated in the electrolytic polishing step. be able to. Since a concentration gradient and a temperature difference are unlikely to occur in the electrolytic polishing liquid 217, a smooth polished surface can be easily obtained.

A rotary connector can be used for the entire anode rotating portion 26 and the anode rotating portion 24 for rotation and power supply.

Further, the cathode 216 has a cylindrical shape that surrounds the outer circumference of each stent 214 so that the distance between the electrodes with the stent 214 is substantially equidistant.
In order to keep the temperature of the electrolytic polishing liquid 217 constant, the electrolytic liquid tank 215 has a circulating water inlet 27 and a circulating water outlet 28.

By rotating the stirrer bar 29 with the magnetic stirrer 200, the electrolytic polishing liquid 217 can be agitated and the uniform state of the liquid can be maintained.

As described above, the electrolytic polishing method for the metal molded body according to the embodiment of the present invention has been described with reference to specific examples, but the present invention is not limited by the above-described embodiment, and the gist of the above and the following will be described. It is also possible to make changes to the extent that it is compatible with, and all of them are included in the technical scope of the present invention.

Hereinafter, the present invention will be described in more detail based on Examples. In all of the following examples, electropolishing was performed using the electropolishing apparatus shown in FIG.

Hereinafter, embodiments of the present invention will specifically show Production Examples 1 to 20 of the electrolytic polishing liquid according to the present invention, and Examples 1 to 30 and Comparative Examples 1 to 5 according to the present invention. The component compositions of the electrolytic polishing solutions of Production Examples 1 to 20 are shown in Tables 1 and 2.

(Production Example 1)
10 g of ethylenediaminetetraacetic acid was dissolved in 990 g of methanesulfonic acid to prepare an electrolytic polishing solution 1.

(Manufacturing Example 2)
Electropolishing solution 2 was prepared by dissolving 10 g of ethylenediaminetetraacetic acid and 0.1 g of polyoxyethylene (10) octylphenyl ether in 990 g of methanesulfonic acid.

(Production Example 3)
Electropolishing solution 3 was prepared by dissolving 10 g of ethylenediaminetetraacetic acid, 0.1 g of polyoxyethylene (10) octylphenyl ether and 1500 g of ethylene glycol in 990 g of methanesulfonic acid.

(Manufacturing Example 4)
10 g of ethylenediaminetetraacetic acid was dissolved in 990 g of methanesulfonic acid to prepare an electrolytic polishing solution 41. Next, 100 g of triethyl orthoacetate was mixed with 1000 g of the electrolytic polishing solution 41 to prepare the electrolytic polishing solution 42.

(Production Example 5)
An electrolytic polishing solution 51 was prepared by dissolving 10 g of ethylenediaminetetraacetic acid and 0.1 g of polyoxyethylene (10) octylphenyl ether in 990 g of methanesulfonic acid. Next, 100 g of triethyl orthoacetate was mixed with 1000.1 g of the electrolytic polishing solution 51 to prepare the electrolytic polishing solution 52.

(Manufacturing Example 6)
An electrolytic polishing solution 61 was prepared by dissolving 10 g of ethylenediaminetetraacetic acid, 0.1 g of polyoxyethylene (10) octylphenyl ether and 1500 g of ethylene glycol in 990 g of methanesulfonic acid. Next, 100 g of triethyl orthoacetate was mixed with 2500.1 g of the electrolytic polishing solution 51 to prepare the electrolytic polishing solution 62.

(Production Example 7)
10 g of ethylenediaminetetraacetic acid was dissolved in 990 g of methanesulfonic acid to prepare an electrolytic polishing solution 71. Next, 100 g of triethyl orthoacetate was mixed with 1000 g of the electrolytic polishing solution 71, then a nickel titanium alloy (compatible with ASTM F2063-05) was dissolved by 4 g / L electrolytic polishing, and 30 g of water was added to the electrolytic polishing solution. 72 was adjusted.

(Manufacturing Example 8)
10 g of ethylenediaminetetraacetic acid was dissolved in 990 g of methanesulfonic acid to prepare an electrolytic polishing solution 81. Next, a nickel titanium alloy (compatible with ASTM F2063-05) was dissolved in 1000 g of electrolytic polishing solution 81 by 4 g / L electrolytic polishing, then 30 g of water was added, and then 100 g of triethyl orthoacetate was mixed and electrolytically polished. Liquid 82 was adjusted.

(Manufacturing Example 9)
An electrolytic polishing solution 91 was prepared by dissolving 10 g of ethylenediaminetetraacetic acid and 0.1 g of polyoxyethylene (10) octylphenyl ether in 990 g of methanesulfonic acid. Next, 100 g of triethyl orthoacetate was mixed with 1000.1 g of the electrolytic polishing solution 91, then the nickel titanium alloy was dissolved by 4 g / L electrolytic polishing, and then 30 g of water was added to prepare the electrolytic polishing solution 92. ..

(Manufacturing Example 10)
An electrolytic polishing solution 101 was prepared by dissolving 10 g of ethylenediaminetetraacetic acid and 0.1 g of polyoxyethylene (10) octylphenyl ether in 990 g of methanesulfonic acid. Next, a nickel titanium alloy (compatible with ASTM F2063-05) was dissolved in 1000.1 g of electrolytic polishing liquid 101 by 4 g / L electrolytic polishing, then 30 g of water was added, and then 100 g of triethyl orthoacetate was mixed. The electrolytic polishing solution 102 was adjusted.

(Manufacturing Example 11)
An electrolytic polishing solution 111 was prepared by dissolving 10 g of ethylenediaminetetraacetic acid, 0.1 g of polyoxyethylene (10) octylphenyl ether and 1500 g of ethylene glycol in 990 g of methanesulfonic acid. Next, 100 g of triethyl orthoacetate was mixed with 2500.1 g of electrolytic polishing solution 111, and then a nickel titanium alloy (compatible with ASTM F2063-05) was dissolved by 4 g / L electrolytic polishing, and then 30 g of water was added. The electrolytic polishing solution 112 was adjusted.

(Manufacturing Example 12)
An electrolytic polishing solution 121 was prepared by dissolving 10 g of ethylenediaminetetraacetic acid, 0.1 g of polyoxyethylene (10) octylphenyl ether and 1500 g of ethylene glycol in 990 g of methanesulfonic acid. Next, a nickel titanium alloy (compatible with ASTM F2063-05) was dissolved in 2500.1 g of electrolytic polishing solution 121 by 4 g / L electrolytic polishing, 30 g of water was added, and then 100 g of triethyl orthoacetate was mixed and electrolytically polished. Liquid 122 was adjusted.

(Manufacturing Example 13)
10 g of ethylenediaminetetraacetic acid was dissolved in 990 g of methanesulfonic acid to prepare an electrolytic polishing solution 131. Next, a nickel titanium alloy (compatible with ASTM F2063-05) was dissolved in 1000 g of the electrolytic polishing liquid 131 by 4 g / L electrolytic polishing, and then 30 g of water was added to prepare the electrolytic polishing liquid 132.

(Manufacturing Example 14)
10 g of ethylenediaminetetraacetic acid and 0.1 g of polyoxyethylene (10) octylphenyl ether were dissolved in 990 g of methanesulfonic acid to prepare an electrolytic polishing solution 141. Next, a nickel titanium alloy (compatible with ASTM F2063-05) was dissolved in 1000.1 g of the electrolytic polishing solution 141 by 4 g / L electrolytic polishing, and then 30 g of water was added to prepare the electrolytic polishing solution 142.

(Manufacturing Example 15)
Electropolishing solution 151 was prepared by dissolving 10 g of ethylenediaminetetraacetic acid, 0.1 g of polyoxyethylene (10) octylphenyl ether and 1500 g of ethylene glycol in 990 g of methanesulfonic acid. Next, a nickel titanium alloy (compatible with ASTM F2063-05) was dissolved in 2500.1 g of the electrolytic polishing solution 151 by 4 g / L electrolytic polishing, and then 30 g of water was added to prepare the electrolytic polishing solution 152.

(Manufacturing Example 16)
10 g of malonic acid was dissolved in 990 g of methanesulfonic acid to prepare an electrolytic polishing solution 16.

(Manufacturing Example 17)
10 g of etidronic acid was dissolved in 990 g of methanesulfonic acid to prepare an electrolytic polishing solution 17.

(Manufacturing Example 18)
10 g of N, N, N', N'-ethylenediamine tetrakis (methylenephosphonic acid) was dissolved in 990 g of methanesulfonic acid to prepare an electrolytic polishing solution 18.

(Manufacturing Example 19)
An electrolytic polishing solution 19 composed of only 1000 g of methanesulfonic acid was prepared.

(Manufacturing Example 20)
An electrolytic polishing solution 201 composed of only 1000 g of methanesulfonic acid was prepared. Next, a nickel titanium alloy (compatible with ASTM F2063-05) was dissolved in 1000 g of the electrolytic polishing solution 201 by 4 g / L electrolytic polishing, and then 30 g of water was added to prepare the electrolytic polishing solution 202.

(Example 1)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.

The object to be polished is inserted through an anode conductive member made of SUS304 having an outer diameter of 10.5 mm so that the object to be polished is evenly expanded in diameter, and the inner surface of the stent is an anode in the cross section of the entire length of the object to be polished. It was fixed so as to form an electrical contact at four points with an elongated member of the conductive member. As the elongated member of the anode conductive member, a columnar member having an outer diameter of 1.2 mm was used.

The electrolytic polishing liquid 1 of Production Example 1 is charged into the electrolytic polishing liquid tank and stored at 25 ° C., and has a curved shape so that the distance between the electrodes with the object to be polished is substantially equidistant to 45 mm to 55 mm. A cathode made of SUS304 was installed.
Power was supplied to the electrolytic polishing liquid at a voltage of 20 V for 20 seconds, and the object to be polished was immersed in the electrolytic polishing liquid to perform electrolytic polishing of the surface of the object to be polished. After the power supply was completed, the object to be polished was washed with water and dried, and the electrical contact between the object to be polished and the anode conductive member was changed.

The above steps were continuously repeated 10 times. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 2)
A wire made of pure titanium having an outer diameter of 1.0 mm was prepared as an object to be polished.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.

Other than that, electrolytic polishing was carried out in the same manner as in Example 1. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 3)
As the object to be polished, a wire made of titanium alloy Ti-6Al-4V having an outer diameter of 1.0 mm was prepared.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.

Other than that, electrolytic polishing was carried out in the same manner as in Example 1. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 4)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 2 of Production Example 2 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 5)
A wire made of pure titanium having an outer diameter of 1.0 mm was prepared as an object to be polished.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 2 of Production Example 2 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 6)
As the object to be polished, a wire made of titanium alloy Ti-6Al-4V having an outer diameter of 1.0 mm was prepared.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 2 of Production Example 2 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 7)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 3 of Production Example 3 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 8)
A wire made of pure titanium having an outer diameter of 1.0 mm was prepared as an object to be polished.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 3 of Production Example 3 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 9)
As the object to be polished, a wire made of titanium alloy Ti-6Al-4V having an outer diameter of 1.0 mm was prepared.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 3 of Production Example 3 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 10)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 42 of Production Example 4 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 11)
A wire made of pure titanium having an outer diameter of 1.0 mm was prepared as an object to be polished.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 42 of Production Example 4 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 12)
As the object to be polished, a wire made of titanium alloy Ti-6Al-4V having an outer diameter of 1.0 mm was prepared.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 42 of Production Example 4 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 13)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing liquid 52 of Production Example 5 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 14)
A wire made of pure titanium having an outer diameter of 1.0 mm was prepared as an object to be polished.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing liquid 52 of Production Example 5 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 15)
As the object to be polished, a wire made of titanium alloy Ti-6Al-4V having an outer diameter of 1.0 mm was prepared.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing liquid 52 of Production Example 5 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 16)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing liquid 62 of Production Example 6 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 17)
A wire made of pure titanium having an outer diameter of 1.0 mm was prepared as an object to be polished.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing liquid 62 of Production Example 6 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 18)
As the object to be polished, a wire made of titanium alloy Ti-6Al-4V having an outer diameter of 1.0 mm was prepared.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing liquid 62 of Production Example 6 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 19)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 72 of Production Example 7 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 20)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing liquid 82 of Production Example 8 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 21)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 92 of Production Example 9 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 22)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 102 of Production Example 10 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 23)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 112 of Production Example 11 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 24)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing liquid 122 of Production Example 12 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 25)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 132 of Production Example 13 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 26)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 142 of Production Example 14 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 27)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 152 of Production Example 15 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 28)
As a material to be polished, a wire made of stainless steel SUS304 having an outer diameter of 1.2 mm was prepared.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Other than that, electrolytic polishing was carried out in the same manner as in Example 1. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 29)
A wire made of magnesium alloy AZ61 having an outer diameter of 1.6 mm was prepared as an object to be polished.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Other than that, electrolytic polishing was carried out in the same manner as in Example 1. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Example 30)
A wire made of pure aluminum A1070 having an outer diameter of 1.5 mm was prepared as an object to be polished.
The extension of the anode conductive member was removed and the wire was attached directly to the anode connection.
Other than that, electrolytic polishing was carried out in the same manner as in Example 1. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Comparative Example 1)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 16 of Production Example 16 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Comparative Example 2)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 17 of Production Example 17 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Comparative Example 3)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 18 of Production Example 18 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Comparative Example 4)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 19 of Production Example 19 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Comparative Example 5)
As an object to be polished, a stent made of nickel titanium alloy (compatible with ASTM F2063-05) having an inner diameter of 10.0 mm was prepared.
Electropolishing was carried out in the same manner as in Example 1 except that the electrolytic polishing solution 202 of Production Example 20 was used. The current densities during all electropolishing were in the range of 100-1000 mA / cm ² .

(Appearance evaluation by stereomicroscope)
The appearance of the metal molded product produced in each example was evaluated by observing the surface appearance at a magnification of 50 times using a stereomicroscope (MM-400 manufactured by Nikon). For Examples 1 to 4, 7, 10, 19, 20, 25, 28 to 30, and Comparative Examples 1 to 3, a digital single-lens reflex camera (EOS Kiss X5 manufactured by Canon) was connected to a stereomicroscope and magnified photographs were taken. The surface observation results are shown in FIGS. 3 to 17, respectively. The results are shown in Table 3.

As a result, in Examples 1 to 24, it was confirmed that all the surfaces were excellent in smoothness. Further, in Examples 25 to 27, although a partially white cloudy surface was confirmed, it was confirmed that almost all the surfaces were excellent in smoothness. In Examples 28 to 30, it was confirmed that all the surfaces were excellent in smoothness.

In Comparative Examples 1 to 4, it was confirmed that polishing unevenness occurred on almost all the surfaces. In Comparative Example 5, polishing unevenness occurred on almost all the surfaces, and a partially white cloudy surface was confirmed.

(Measurement of surface roughness with a laser microscope)
The arithmetic average roughness Ra and the maximum height Ry were measured for the metal molded bodies produced in Example 1 and Comparative Example 1 using a laser microscope (manufactured by KEYENCE, VK-9510) based on JIS B0601-1994. The surface roughness measurement results of Example 1 and Comparative Example 1 are shown in Table 4. It was found that the arithmetic mean roughness Ra and the maximum height Ry of Example 1 were both smaller than those of Comparative Example 1, and that Example 1 was superior to Comparative Example 1 in smoothness. In addition, 3D surface images of the metal molded products produced in Example 1 and Comparative Example 1 observed at 1000 times using a laser microscope (manufactured by KEYENCE, VK-9510) are shown in FIGS. 18 and 19, respectively.

(result)
In Examples 1 to 30, it was confirmed that due to the effect of the present invention, the metal molded body was electropolished to obtain a polished surface having excellent smoothness. As can be seen from the results of Examples 25 to 27, even in the electrolytic polishing liquid having a reduced polishing effect, a white cloudy surface was partially observed, but a smooth polished surface was obtained as a whole. It was confirmed that.

On the other hand, in Comparative Examples 1 to 4, polishing unevenness was confirmed in many parts of the stent surface. In Comparative Example 5 in which the electrolytic polishing solution having a reduced polishing effect was used, uneven polishing occurred in many parts of the stent surface, and a white cloudy surface was partially confirmed. In Comparative Examples 1 to 3, an electrolytic polishing solution containing a chelating agent of a type different from that used in the present invention was used, but on the contrary, uneven polishing occurred, and all chelating agents were not necessarily used. It can be seen that it does not contribute to the polishing effect.

Further, as can be seen from the results of Examples 19 to 24, due to the further effect of the present invention, even in the electrolytic polishing liquid containing the metal molded product component by electropolishing, no white cloudy surface is observed and electrolysis is performed. It was confirmed that a very smooth polished surface similar to the initial state of the polishing liquid could be obtained.

From this, according to the present invention, it is possible to maintain an excellent polishing effect by a simple method having excellent practicality, and to produce a metal molded body having a uniform polishing surface with less uneven polishing.

11 Power supply 12a, 12b Conductive wire 13 Anode conductive member 14 Metal molded body 15 Electrolytic polishing liquid tank 16 cathode 17 Electrolytic polishing liquid 18 Electrical contact 21 Elongated member 22 Extension part 23 Anode connection part 24 Anode rotating part 25 Anode support part 26 Anode overall rotating part 27 Circulating water inlet 28 Circulating water outlet 29 Stirrer bar 200 Magnetic stirrer 211 Power supply 212 Conductive wire 213 Anode conductive member 214 Stent 215 Electrolytic polishing liquid tank 216 Cathode 217 Electrolytic polishing liquid 218 Electrical contact

Claims (22)

An electrolytic polishing solution for electrolytically polishing a metal molded body, which contains an alkyl sulfonic acid, one or more aminocarboxylic acid type chelating agents, and an orthoester compound . The electrolytic polishing solution according to claim 1, wherein the content of the alkyl sulfonic acid is 20% by weight or more and 99.9% by weight or less. The electrolytic polishing solution according to claim 1 or 2, wherein the content of the aminocarboxylic acid type chelating agent is 0.1% by weight or more and 5% by weight or less. The electrolytic polishing solution according to any one of claims 1 to 3, wherein the aminocarboxylic acid type chelating agent is at least one selected from ethylenediaminetetraacetic acid and ethylenediaminetetraacetic acid salt. The orthoester compounds include triisopropyl orthoester, tributyl orthoate, triethyl orthoacetate, triethyl orthoate, triethyl orthopropionate, triethyl orthovalerate, trimethyl orthoacetate, trimethyl orthobutyrate, trimethyl orthoacetate, orthoiso. The electropolishing solution according to any one of claims 1 to 4, wherein the electrolytic polishing solution is at least one selected from trimethyl butyrate, trimethyl orthopropionate, trimethyl orthovalerate, and tripropyl orthoformate. The electrolytic polishing solution according to any one of claims 1 to 5 , wherein the electrolytic polishing solution contains a nonionic surfactant. The nonionic surfactant is one or more selected from polyoxyethylene alkyl ethers having 1 to 30 molar additions of ethylene oxide and polyoxyethylene alkyl phenyl ethers having 1 to 30 molar additions of ethylene oxide. The electrolytic polishing solution according to claim 6 , wherein the electrolytic polishing solution is provided. The electrolytic polishing solution according to claim 6 or 7 , wherein the content of the nonionic surfactant is 0.001% by weight or more and 0.1% by weight or less. The electrolytic polishing solution according to claim 1 to 8 , wherein the electrolytic polishing solution contains glycols. The electrolytic polishing solution according to claim 9 , wherein the glycols are ethylene glycol. The electrolytic polishing solution according to claim 9 or 10 , wherein the content of the glycols is 1% by weight or more and 80% by weight or less. A method for producing a metal molded body, which comprises using the electrolytic polishing solution according to any one of claims 1 to 11 and comprising an electrolytic polishing step of applying a voltage for a certain period of time at least once. A step of mixing an orthoester compound with an electrolytic polishing solution containing an alkylsulfonic acid and one or more aminocarboxylic acid type chelating agents, which is an electrolytic polishing solution for electrolytically polishing a metal molded body, and a voltage. method of manufacturing features and to Rukin genus moldings that comprise one or more times electropolishing step of applying a certain time. The ortho ester compound, orthoformate, triisopropyl orthoformate, tributyl orthoacetate triethyl Le, OH belt formic acid triethyl orthopropionate triethyl orthovalerate, triethyl orthoacetate, trimethyl orthobutyrate, trimethyl orthoformate The method for producing a metal molded product according to claim 13 , wherein the metal molded product is at least one selected from trimethyl orthoisobutyrate, trimethyl orthopropionate, trimethyl orthovalerate, and tripropyl orthoformate. The method for producing a metal molded product according to claim 13 or 14 , wherein the orthoester compound is mixed in an amount of 0.1% by weight or more and 40% by weight or less based on the weight of the electrolytic polishing liquid before mixing. The method for producing a metal molded body according to any one of claims 12 to 15 , wherein the metal molded body is a metal molded body made of a base metal. The method for producing a metal molded body according to claim 16 , wherein the metal molded body is a metal molded body containing at least one selected from iron, chromium, magnesium, aluminum, and titanium. The method for producing a metal molded body according to claim 17 , wherein the metal molded body is titanium or a titanium alloy. The method for producing a metal molded body according to claim 18 , wherein the metal molded body is a nickel titanium alloy. The method for producing a metal molded body according to any one of claims 12 to 19 , wherein the metal molded body is a medical tubular body. The method for producing a metal molded body according to claim 20 , wherein the medical tubular body is a stent. The method for manufacturing a medical catheter having the stent according to claim 21 .