Polishing compositions and uses thereof

Abstract

The present invention relates to a polishing composition and its use. Specifically, it relates to a highly efficient, stable, and high-precision polishing composition. The polishing composition comprises an acid, an oxidizing agent, and water, wherein the acid is selected from inorganic acids and the oxidizing agent is selected from inorganic oxidizing agents, and the pH value of the polishing composition is 1 or less. The polishing composition of the present invention is suitable for polishing medical devices, particularly for polishing medical devices requiring a relatively large removal rate. When used for polishing, the composition has the advantages of high polishing precision, simple and convenient operation, and low cost. Furthermore, the polished product has relatively good mechanical properties, surface properties, and biological safety.

Description

[Technical Field]

[0001] The present invention relates to the field of pure chemical polishing, and more particularly to highly efficient, stable and precise polishing compositions. [Background technology]

[0002] In recent years, with the rapid development of the medical device industry, research and development of various types of medical devices has been actively carried out, but most medical devices have higher requirements in terms of smoothness of edges and corners, uniformity of size and strength of each part of the device during use, etc. The polishing process is a key factor that affects the above properties, so high requirements are also placed on the polishing process and polishing composition of medical devices.

[0003] Currently, commonly used polishing methods for metal surface treatment include electrochemical polishing, chemical polishing, mechanical polishing, and chemical-mechanical polishing. In these commonly used polishing methods, the polishing process is typically divided into several steps to prevent the newly polished surface formed by polishing from rapid oxidation in air and ensure the stability of the device surface. This involves first polishing the polished part, and then cleaning and passivating the newly polished surface. This process is relatively complex. In electrochemical polishing, large differences in current density exist at different positions in the electrolytic bath. Therefore, if the overall removal volume of the polished part is large, large differences in the polishing removal volume at different positions on the pre-polished part are likely to occur, resulting in poor size uniformity at each position on the pre-polished part. Mechanical polishing or chemical-mechanical polishing typically involves adding an abrasive to the polishing composition and using a mechanical grinding method to remove some of the material from the pre-polished part, thereby achieving the desired effect. However, the presence of the abrasive tends to adhere and remain on the polished part, and also easily scratches the surface of the polished part, resulting in an insufficiently smooth surface. Therefore, mechanical polishing methods are not suitable for technical fields such as medical devices, which have strict product requirements. Furthermore, mechanical polishing methods are limited in the size of the polished parts, making them unsuitable for polishing small parts with complex structures. Chemical polishing has the advantages of low cost and simple operation, but its use is limited by the components commonly used in chemical polishing, such as inorganic acids and strong bases.

[0004] Currently, in the field of medical devices, the amount of material removed by the polishing process of existing medical devices is small, so electrochemical polishing can meet the requirements of existing equipment, such as uniformity. Therefore, electrochemical polishing is still commonly used. For example, Patent CN102356184B describes a method and a method for electrochemical polishing a stent made of high-strength medical alloy. solutionThis method requires one or more conductive adapters to be attached to each stent, and also requires a current-conducting member for connecting the cathode and anode. It not only places high requirements on equipment, but also requires the entire polishing process to be repeated four times in an example. It also discloses that after polishing, the cleaned stent is immersed in a passivation solution to passivate the newly polished surface formed by polishing, thereby preventing the newly polished surface from being rapidly oxidized in air. The polishing process disclosed in this patent has problems such as complicated steps and tedious operation. Summary of the Invention [Problem to be solved by the invention]

[0005] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a chemical polishing composition and its use, in which each component of the chemical polishing composition is a relatively common compound and is low in cost. When polishing is performed using the polishing composition, the polishing process flow is simple, the operation is easy, the polishing conditions are mild, the timing is appropriate and controllable, and the reproducibility is excellent, which contributes to the precision control of the polished stent. Furthermore, after polishing, the polished parts have uniform size at each position, smooth surfaces, no burrs, rounded edges and corners, high precision, and excellent stability. Furthermore, after polishing, the polished parts have excellent mechanical properties. [Means for solving the problem]

[0006] The technical solution of the present invention provides a polishing composition, which comprises an acid, an oxidizing agent, and water, wherein the acid is at least one selected from inorganic acids, and the oxidizing agent is at least one selected from strong inorganic oxidizing agents, and the pH of the polishing composition is 1 or less; further, the pH value of the polishing composition used in the present invention is 0.8 or less, 0.5 or less, and further, the pH value of the polishing composition used in the present invention is 0.2 or less.

[0007] In the present invention, by using a specific type of inorganic acid and a strong oxidizing agent and adjusting their contents, the oxidation and corrosion rate of the surface of the pre-polished part can be fully controlled, and the removal amount of the device surface can be increased to completely remove the cracks inside the pre-polished part generated in the previous step, thereby improving the mechanical properties of the polished part and meeting the requirements for the mechanical properties of various devices, while fully improving the polishing efficiency of the polished part and reducing the polishing cost.

[0008] The inorganic acid in the polishing composition according to the present invention is at least one selected from sulfuric acid, phosphoric acid, nitric acid, perchloric acid, or hydrofluoric acid; in some embodiments of the present invention, the inorganic acid in the polishing composition is sulfuric acid; in some other embodiments of the present invention, the inorganic acid in the polishing composition is a mixed acid of phosphoric acid and nitric acid; and in some further embodiments of the present invention, the inorganic acid in the polishing composition is perchloric acid.

[0009] The inorganic strong oxidizing agent in the polishing composition according to the present invention is at least one selected from the group consisting of persulfates, perchloric acid and its salts, perbromic acid and its salts, periodic acid and its salts, permanganic acid and its salts, peroxides, iodic acid and its salts, chlorous acid and its salts, hypochlorous acid and its salts, hypoiodous acid and its salts, oxybromic acid and its salts, percarbonates, bromic acid and its salts, chloric acid and its salts, hydrogen peroxide, potassium nitrate, and sodium nitrate. In some embodiments of the present invention, the inorganic strong oxidizing agent is one of the above oxidizing agents, and in some further embodiments, the inorganic strong oxidizing agent is a mixture of two or more of the above strong oxidizing agents.

[0010] In the above technical solutions according to the present invention, the mass percentage of the inorganic acid in the polishing composition is 40% to 70%, and further, the mass percentage of the inorganic acid in the polishing composition is 45% to 70%, 48% to 70%, 50% to 70%, 53% to 70%, 55% to 70%, 58% to 70%, 40% to 65%, 40% to 68%, 40% to 63%, 40% to and the mass percentage of the inorganic acid is 45% to 65%, 45% to 68%, 45% to 63%, 45% to 60%, 45% to 58%, 45% to 55%, 45% to 53%, 45% to 50%, 50% to 65%, 55% to 60%, or 50% to 60%.

[0011] In the above technical solutions according to the present invention, the mass percentage of the oxidizing agent in the polishing composition is 5% to 10%, and further, the mass percentage of the oxidizing agent in the polishing composition is 5% to 8%, 5% to 9%, 5% to 9.5%, 5% to 8.5%, 5.5% to 9.5%, 5.5% to 10%, 6% to 10%, 6.5% to 10%, 7% to 10%, 5% to 7%, 6% to 9%, or 6% to 8%, and further, the mass percentage of the oxidizing agent in the polishing composition is 6% to 7% or 5% to 6%.

[0012] In the present invention, the term "polishing composition" means a "polishing liquid." That is, the terms "polishing composition" and "polishing liquid" can be used interchangeably.

[0013] In the present invention, the viscosity of the polishing liquid is adjusted to control the degree of roundness of the device after polishing. In the present invention, by controlling the viscosity of the polishing liquid within a predetermined range, the sharp edges of the device can be sufficiently polished to be smooth and rounded, and burrs and sharp corners at the edges can be eliminated. It is also possible to prevent a certain portion of the device from being over-polished, resulting in the formation of depressions on the surface, which can adversely affect the surface smoothness and flatness, or to prevent the polished part from being smeared with the polishing liquid due to excessive viscosity. rotate Ensure that medical devices meet the corresponding safety requirements without being unable to do so. The technical solution of the present invention has high requirements for the viscosity of the polishing liquid, and the viscosity of the polishing liquid must not be too high, otherwise it will affect the rotation of the stent, and further affect the polishing speed and polishing uniformity of the stent. Also, if the polishing liquid is too viscous, it will not flow smoothly along the inner wall of the stent, resulting in problems such as the inside of the stent being insufficiently polished, relatively deep scratches on the inner wall, poor polishing appearance, and poor mechanical properties of the polished stent. On the other hand, if the viscosity of the polishing liquid is insufficient, the roundness of the polished stent will be insufficient, and the removal of burrs on the surface of the stent and scratches inside the stent base will be poor.

[0014] In the above technical solution according to the present invention, the viscosity of the polishing liquid is: 1 mPa s to 4 mPa s, and the viscosity of the polishing liquid is 1.5 mPa s to 4 mPa s, 1.2 mPa s to 4 mPa s, 1.4 mPa s to 4 mPa s, 1.6 mPa s to 4 mPa s, 1.2 mPa s to 3.5 mPa s, 1.4 mPa s to 3.5 mPa s, 1.6 mPa s to 3.5 mPa s, 1 mPa s to 3.5 mPa s, 1.8 mPa s to 3.5 mPa s, 2.0 mPa s to 3.5 mPa s, 1.2 mPa s to 3.4 mPa s, 1 The viscosity of the polishing liquid is 1.2mPa s to 3.2mPa s, 1.2mPa s to 3.6mPa s, 1.2mPa s to 3.0mPa s, and 1.4mPa s to 3.3mPa s, and the viscosity of the polishing liquid is 1.4mPa s to 3.0mPa s, 1.4mPa s to 3.2mPa s, 1.6mPa s to 3.0mPa s, and 1.6mPa s to 2.9mPa s. In some embodiments of the present invention, the viscosity of the polishing liquid is 1.9 mPa s, 1.7 mPa s, 2.1 mPa s, 2.3 mPa s, 2.5 mPa s, 2.7 mPa s, 2.9 mPa s, 3.0 mPa s, 3.1 mPa s, or 3.3 mPa s, and in some other embodiments, the viscosity of the polishing liquid is 3.5 mPa s, 3.7 mPa s, or 3.9 mPa s.

[0015] In the above technical solution of the present invention, a thickener is used to further adjust the viscosity of the polishing liquid, and the mass percentage of the thickener is 1.5% to 7%, and further, the mass percentage of the thickener is 2% to 7%, 2.5% to 7%, 3% to 7%, 3.5% to 7%, 4.5% to 7%, 4% to 7%, 3.5% to 6.5%, 2.5% to 6.5%, 2 % to 6.5%, and further, the mass percentage of the thickener is 2% to 6%, 2.5% to 6%, 3% to 6%, 4% to 6%, 3.5% to 6%, or 1.5% to 6%.

[0016] In the above technical solution according to the present invention, the thickening agent in the polishing composition is selected from the group consisting of alcohol, silicic acid, silicates, alginic acid, alginates, polyvinylpyrrolidone, modified organic substances of polyvinylpyrrolidone, ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl celluloses, polyacrylic acid, sodium polymethacrylate, sodium polycarboxylate, sodium carboxylate copolymer, carboxylic acid sulfonic acid copolymer, guar gum, sodium starch phosphate, sodium polyacrylate, polyoxyethylenes, carbomer, xanthogenic acid, mosquito The thickening agent is at least one selected from the group consisting of lageenan, agar, gelatin, gum arabic, and derivatives thereof. For example, in some embodiments of the present invention, the thickening agent of the polishing composition is silicic acid, in other embodiments, the thickening agent is hydroxypropyl methylcellulose, and in further embodiments, the thickening agent is a composition of a gum arabic derivative and alcohol.

[0017] In the above technical solution of the present invention, the thickening agent in the polishing composition comprises at least one component A and at least one component B; Component A is alcohol, ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, polyvinylpyrrolidone, polyacrylic acid, polymethacrylic acid sodium, at least one selected from polycarboxylic acid sodium salts, carboxylic acid sodium salt copolymers, carboxylic acid sulfonic acid copolymers and derivatives thereof; Ingredient B is silicic acid, silicates, alginic acid, alginates, modified organic substances of polyvinylpyrrolidone, guar gum, sodium starch phosphate, sodium polyacrylate, polyoxyethylenes, carbomer, xanthogenic acid, mosquito At least one selected from the group consisting of lageenan, agar, gelatin, gum arabic and derivatives thereof in be.

[0018] In some embodiments of the present invention, the thickening agents are ethyl cellulose and guar gum, and in some other embodiments, the thickening agents are sodium silicate and sodium polymethacrylate.

[0019] In the above technical solution of the present invention, the mass ratio of component A to component B of the thickening agent in the polishing composition is 0.5:1 to 15:1. Furthermore, the mass ratio of component A to component B of the thickening agent is 0.5:1 to 10:1, and the mass ratio of component A to component B of the thickening agent is 1.5:1 to 10:1.

[0020] In the above technical solution of the present invention, the molecular weight Mn of the alcohol in the thickener is 800 g / mol or less, and further, Alcohol in has a molecular weight of 720 g / mol or less, and further, the alcohol and its derivatives in the present invention refer to alcohols that are liquid at room temperature, which may be linear or branched, such as butylene glycol, and the positions of the hydroxyl groups may not be fixed, and four methyl, methylene, and / or methine groups may be arranged in a linear chain, or the carbon chain may contain a quaternary carbon atom, and further, the positions of the two hydroxyl groups may be freely changed on the four carbon atoms, and the same applies to others.

[0021] In the above technical solution according to the present invention, the alcohol and its derivatives are at least one of monoalcohol monomers and polyol monomers having 6 or less carbon atoms, and polymers formed from monoalcohols or polyols having 6 or less carbon atoms. In the present invention, "or less" means that it may be less than or equal to, and in the present invention, "monoalcohols and polyols having 6 or less carbon atoms" means monoalcohols or polyols having less than or equal to 6 carbon atoms.

[0022] In the above technical solution according to the present invention, the alcohol and its derivatives are at least one of ethylene glycol, propylene glycol, glycerol, butylene glycol, polyethylene glycol, butanol, cyclohexanol, polypropylene glycol, and polybutylene glycol.

[0023] In the above technical solution of the present invention, by further adding a certain type and mass content of complexing agent to the polishing composition containing an inorganic acid and a strong oxidizing agent, the complexing agent can be sufficiently bonded with the metal ions generated by polishing, so as to avoid the content of metal ions being too high, and the service life of the polishing liquid can be sufficiently extended.

[0024] In the above technical solutions according to the present invention, the mass percentage of the complexing agent is 0.5%-2%, and further, the mass percentage of the complexing agent is 1%-2%.

[0025] In the above technical solution according to the present invention, the complexing agent has a monodentate or polydentate ligand, and the complexing agent is selected from the group consisting of amino, carboxyl, cyanide, thiocyanide, isothiocyanide, nitro, hydroxyl, sulfhydryl, aromatic heterocyclic group, nitroso, sulfo, phosphate group and organophosphino group. mosquito At least one selected from the above.

[0026] In the above technical solution according to the present invention, said complexing agent is at least one selected from hydroxyl carboxylic acids, amino carboxylic acids, hydroxyamino carboxylic acids, hydroxyl phosphonic acids, dicarboxylic acids and salts thereof.

[0027] In the above technical solution according to the present invention, the complexing agent is selected from the group consisting of oxalic acid, aminotrimethylene phosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetramethylene phosphonic acid, J ethylenetriaminepentacarboxylic acid, workman ethylenediaminetetraacetic acid, diethylenetriaminepentamethylenephosphonic acid, 2 -hydroxyphosphonoacetic acid, dihexenetriaminepentamethylenephosphonic acid, 2-phosphono-1,2,4-butanetricarboxylic acid, heptose acid, stomach Taconic acid, succinic acid, tartaric acid, maleic acid, glycolic acid, malonic acid, R Glycolic acid, gluconic acid, alanine, glycine, lactic acid, diethylenetriaminepentaacetic acid, triethylenediamine, propylenediaminetetraacetic acid, hydroxyethylethylenediamine, hydroxyethylethylenediaminetriacetic acid, pyrophosphoric acid, 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, J Ethylenetriaminepentamethylenephosphonic acid, ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, methanehydroxyphosphonic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid and its salts, dihydroxyglycine, disodium EDTA, Po The at least one selected from vinyl alcohol, triethanolamine and salts thereof.

[0028] In addition, "a certain component in the polishing composition of the present invention is at least one selected from a, b, c, d and their derivatives," or "a certain component in the polishing composition of the present invention is at least one selected from a, b, c, d and their salts," means that "a certain component in the polishing composition is at least one selected from a, a derivative, b, b derivative, c, c derivative, and d, d derivative," or "a certain component in the polishing composition is at least one selected from a, a salt, b, b salt, c, c salt, and d, d salt." For example, "the complexing agent is at least one selected from hydroxyl carboxylic acid, amino carboxylic acid, hydroxyamino carboxylic acid, hydroxyl phosphonic acid, dicarboxylic acid, and salts thereof" means that the complexing agent is at least one selected from hydroxyl carboxylic acid, amino carboxylic acid, hydroxyamino carboxylic acid, hydroxyl phosphonic acid, dicarboxylic acid, hydroxyl carboxylate, amino carboxylate, hydroxyamino carboxylate, hydroxyl phosphonate, and dicarboxylate.

[0029] In the present invention, the certain salts refer to the sodium salts, potassium salts, ammonium salts, calcium salts, and magnesium salts formed by the corresponding acids and the corresponding metal ions. For example, alginates include sodium alginate, potassium alginate, ammonium alginate, calcium alginate, and magnesium alginate, and silicates include aluminum silicate, iron silicate, calcium silicate, magnesium silicate, potassium silicate, and sodium silicate, and the same applies to others.

[0030] In the technical solution of the present invention, a surface protective agent is further added to the polishing composition containing an inorganic acid and an oxidizing agent, thereby ensuring that a thin protective film is formed on the surface of the polishing part after the polishing part is polished, preventing the polishing part from being oxidized in the air, and ensuring that the polishing part maintains its gloss and smoothness for a long period of time. It can also improve the chemical stability of the polishing part and extend its storage period and service life.

[0031] In the above technical solution according to the present invention, the polishing composition further comprises a surface protective agent, and the mass percentage of the surface protective agent is 0.02% to 1%, and further, the mass percentage of the surface protective agent is 0.05% to 0.7%, 0.05% to 0.8%, 0.05% to 0.6%, 0.05% to 0.5%, 0.05% to 0.4%, 0.05% to 0.3%, 0.05% to 0.2%, 0.05% to 0.1%, 0.1% to 0.8%, 0.1% to 0.7%, 0.1% to 0.6%, 0.1% to 0.5%, 0.1% to 0.4%, or 0.1% to 0.3%, 0.1% to 0.9%, or 0.05% to 1%.

[0032] In the above technical solution according to the present invention, the surface protective agent is at least one selected from tannic acid, phytic acid, stearic acid, palmitic acid, and salts thereof, i.e., the surface protective agent may be at least one of tannic acid, phytic acid, stearic acid, palmitic acid, a tannate, a phytate, a stearate, or a palmitate, or a mixture of at least one of tannic acid, phytic acid, stearic acid, or palmitic acid with at least one of tannate, a phytate, a stearate, or a palmitate, and the salts include, but are not limited to, sodium salt, potassium salt, ammonium salt, calcium salt, or magnesium salt.

[0033] In the technical solution of the present invention, a surfactant of a certain type and mass content is further added to the polishing composition containing an inorganic acid and a strong oxidizing agent, thereby reducing the surface tension of the liquid with the surfactant, thoroughly dispersing each component in the polishing liquid and contributing to the flow of the polishing liquid along the inner and outer walls of the stent, thereby making the components of the polishing liquid near each part of the preliminary polished part approximately the same, and further making the effects of the polishing liquid on each part of the preliminary polished part approximately the same, ultimately ensuring the uniformity of the surface of the finished polished part. In addition, the surfactant has a certain thickening effect on water, and has excellent affinity and wettability with the surface of the polishing part, so it can penetrate into the metal surface and improve the polishing effect of the polishing liquid on the metal, and can repair dents, scratches and unevenness on the surface of the polishing part, thereby improving the flatness and gloss of the workpiece and making the surface of the polished part bright and flat.

[0034] In the above technical solution according to the present invention, the surfactant is at least one of an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant.

[0035] In the above technical solution of the present invention, the mass percentage of the surfactant is 0.05% to 1%, and further, the mass percentage of the surfactant is 0.05% to 0.7%, 0.05% to 0.8%, 0.05% to 0.6%, 0.05% to 0.5%, 0.05% to 0.4%, 0.05% to 0.3%, 0.05% to 0.2%, 0.05% to 0.1%, 0.1% to 0.8%, 0.1% to 0.7%, 0.1% to 0.6%, 0.1% to 0.5%, 0.1% to 0.4%, or 0.1% to 0.3%, 0.1% to 0.9%. in be.

[0036] In the above technical solution according to the present invention, the surfactant is selected from the group consisting of higher fatty acid salts, alkyl sulfonates, alkyl ether carboxylate surfactants, silicone surfactants, alkane sulfates, Placeand at least one selected from the group consisting of alkyl substituted amine salts, betaine, polyethylene oxide, polyvinyl alcohol, polyvinyl acetate, polyacrylic acid, polyvinylpyrrolidone, lecithin, amino acid derivatives, alkylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ether sodium sulfate, isooctanol polyoxyethylene ethers, alkyl glucosides, polyoxyethylene ethers, polyethyleneimines, alkyl trimethyl quaternary ammonium salts, alkyl dimethyl benzyl ammonium chloride salts, and pyridinium salts.

[0037] In the above technical solution according to the present invention, the surfactant may be selected from the group consisting of sodium dodecyl sulfate, sodium dodecyl sulfonate, OP-10, sodium linear alkylbenzene sulfonate (LAS), sodium fatty alcohol polyoxyethylene ether sulfate (AES), ammonium fatty alcohol polyoxyethylene ether sulfate (AESA), sodium lauryl sulfate (SDS), lauroyl glutamic acid, nonylphenol polyoxyethylene ether (TX-10), glyceryl stearate monoester, lignosulfonates, heavy alkylbenzene sulfonates, alkyl sulfonates, diffusing agent NNO, diffusing agent MF, alkyl polyether (PO-EO copolymer), fatty alcohol polyoxyethylene ether (AEO-3), betaine, alkyltrimethyl quaternary ammonium salt, lecithin, amino acid derivatives, alkylphenol polyoxyethylene ether, stomach The alkyl dimethylbenzyl ammonium chloride salt is at least one selected from the group consisting of octanol polyoxyethylene ether, alkyl glucoside, polyoxyethylene ether, alkyl dimethyl benzyl ammonium chloride salt, and pyridinium salt.

[0038] In the above technical solution according to the present invention, the present invention also provides a use of the polishing composition in polishing a medical device.

[0039] In the above technical solution of the present invention, the medical device has a relatively small mass, and the mass of the abrasive part of one medical device is generally 0.5 kg Here, the abrasive part of one medical device may be a part of a particular medical device, or may be the entirety of a certain medical device.

[0040] In the above technical solution according to the present invention, the medical device is a degradable medical device.

[0041] In the above technical solutions according to the present invention, the medical device includes an iron-containing medical device, and the iron-containing medical device may refer to a device composed only of iron element, or a device composed of iron element and other elements, and may be a pure iron material or an iron-containing alloy. The iron-containing medical device may be a device in which the entire device contains an iron material, or a member or part of the device may be made of an iron-containing material.

[0042] In the above technical solutions according to the present invention, the medical device includes an intervention material / device or an implantable material / device used in vivo.

[0043] In the above technical solution of the present invention, the medical device teeth , a degradable metal or metal alloy, and the medical device includes a vascular stent, a non-intravascular stent, an occluder, a spacer, a vascular prosthesis, a dental implant device, a vascular clamp, a prosthetic heart valve, an orthopedic implant, a dental implant, a respiratory implant, a gynecological implant, a male medical implant, a suture, or a bolt. The orthopedic implant includes a bone nail, a bone plate, etc.

[0044] The polishing composition of the present invention is suitable for polishing metals, particularly iron-based or iron-based alloys, including low-alloy steels or iron-based alloys with a carbon content of 2.5 wt.% or less. Furthermore, the polishing composition of the present invention is suitable for polishing small products with complex structures.

[0045] In the above technical solution according to the present invention, the mass-to-volume ratio of the abrasive part of the medical device is 0.001 g / cm 3 ~0.4g / cm 3 and the mass-to-volume ratio of the abrasive component of the medical device is 0.002 g / cm 3 ~0.3g / cm 3 and the mass-to-volume ratio of the abrasive component of the medical device is 0.005 g / cm 3 ~0.25g / cm 3 is.

[0046] In the above technical solution according to the present invention, the iron-containing medical device is pure iron or an iron-based alloy with a carbon content of 2.11 wt% or less.

[0047] In the present invention, " / " means "or", for example, "intervention material / device" means "intervention material or intervention device".

[0048] The mass percentage of each component described in this invention refers to the mass percentage of the main component of each component as a solute in the entire polishing composition. When component M itself is a solution and its solute is J, the mass percentage of this component in the polishing composition refers to the mass percentage of J in the entire polishing composition K, not the mass percentage of M in the entire polishing composition, that is, the mass of J and polishing It is a percentage of the mass of composition K.

[0049] The mass % of each component in the polishing composition of the present invention plus the mass % of water is 100%. polishing The composition is a mixed solution of each major component and water.

[0050] In the present invention, by rationally combining each component and controlling the relative content of each component, each component is blended and cooperated with each other, ultimately ensuring that the abrasive part has a smooth, round and bright surface, with no burrs on the surface, no edges or corners, reducing the irritation and damage caused by the device to the human body, and also fully improving the mechanical properties of the device, so as to meet the corresponding requirements for mechanical properties in various application scenarios.

[0051] The polishing composition of the present invention has high polishing efficiency, and can stably maintain each parameter after polishing two or more polishing parts, ensuring high polishing precision and controllable product weight.

[0052] When polishing components using the polishing composition of the present invention under specified conditions, the removal rate of the polished component after polishing can reach 20% to 60%, and the polishing uniformity at each part of the device can reach 85%, 90%, 95%, or even 98% or more. When each part of the polished component after polishing was magnified 200 times using an optical microscope, all of them had bright, smooth surfaces and were free of scratches, and no signs of fracture were observed even when the polished component was bent, stretched, or expanded hundreds of times.

[0053] Since all of the components in the polishing composition of the present invention are common compounds, it is low in cost. When polishing is performed using this polishing composition, the polishing process flow is simple, the operation is easy, the polishing conditions are mild, the timing is appropriate and controllable, and the reproducibility is excellent, which not only contributes to the precision control of the polished stent, but also when multiple identical stents are polished under the same conditions, the RSD of the weights of multiple polished stents is within 2%, or even within 0.8%.

[0054] With the polishing composition of the present invention, the polished parts have uniform size at each position, smooth surfaces, no burrs, rounded edges and corners, high precision, and excellent stability, and furthermore, the polished parts have excellent mechanical properties.

[0055] The polishing process of the present invention is simple to operate; it is sufficient to place the pre-polished part in the prepared polishing solution and polish it under specified conditions for several minutes or several tens of minutes. High-quality polished parts can be obtained without the need for subsequent steps such as passivation, and the polishing stability and reproducibility of the polished parts are high.

[0056] When the polishing composition of the present invention is used, the polishing composition is used to polish the polishing part of the device. When the polishing composition is used to polish the polishing part and the finished product is magnified 500 times under an SEM electron microscope, slight scratches are found on the surface of the polishing part, but the ratio of the area of ​​the scratches to the total surface area of ​​the polishing part is 20% or less. Furthermore, when the polishing part of the present invention is magnified 500 times under an SEM electron microscope, the area of ​​the scratches on the surface of the polishing part is 15% or less, 10% or less, or even 6% or less of the total surface area of ​​the polishing part.

[0057] In the polishing composition of the present invention, the scratch depth h of the finished product obtained by polishing an abrasive part in the polishing composition is 2.5 μm or less, and further, the scratch depth of the abrasive part may be less than 1 μm, and further, the scratch depth of the abrasive part may be less than 0.5 μm or less than 0.3 μm.

[0058] In the polishing composition of the present invention, the surface roughness Sa of the finished product obtained by polishing an abrasive part in the polishing composition is 50 nm or less, and further, the surface roughness Sa of the abrasive part of the medical device is 30 nm or less, and further, the surface roughness Sa of the abrasive part of the medical device is 20 nm or less.

[0059] In the polishing composition of the present invention, a thin protective film is formed on the surface of the finished product obtained by polishing an abrasive part in the polishing composition, which gives the surface of the abrasive part excellent stability and makes it less susceptible to oxidation by air, etc., ensuring the stability of the surface appearance and performance during transportation and storage of the abrasive parts of the device.

[0060] In the polishing composition of the present invention, when the finished product obtained by polishing an abrasive part in the polishing composition was magnified 100 times under an optical electron microscope, a smooth and bright surface was observed, and further, when the polished part was magnified 200 times or 250 times under an optical electron microscope, a smooth and bright surface was also observed.

[0061] The polishing composition of the present invention can fully control the amount of removal by polishing at each part of the polishing process of the polishing part of the medical device, and can ensure that the polishing uniformity of the polishing part is 85% or more, more preferably 90%, 95%, or even 98% or more, thereby ensuring that there are no weak parts throughout the polishing part of the medical device and that the mechanical properties are excellent throughout. In the present invention, the polishing uniformity of the polishing part refers to the relatively uniform size of the polishing part after polishing, that is, the polishing uniformity is the ratio of the width / thickness R of a certain part of the polishing part after polishing. i and the average width / thickness of the corresponding part of the polished part after polishing R 平均 For example, in the process of polishing the polished parts of a medical device, the size uniformity of each part after polishing reaches 85% or more refers to ≧85%.

[0062] The polishing composition of the present invention has relatively high stability in the process of polishing polishing parts, and even when polishing dozens of stents at the same time, the stents have a stable and relatively good appearance, and each parameter such as the size and weight of the stents is stable and stable.

[0063] Although the advantages of the technical solutions of the present invention have been described individually for the sake of convenience, the form provided by the present invention is an inseparable whole, and the final effect can only be achieved when the various components of the form cooperate and interact with each other. A particular component alone cannot achieve very good results without the assistance of other components. For example, the thickening agent in the present invention can improve the surface smoothness of the abrasive part, but the viscosity of the solution is not the result of the thickening agent alone, but the result of the interaction of all the components. That is, without the cooperation of all the components, the smooth surface of the abrasive part after polishing cannot be achieved.

[0064] The value of the interval range according to the present invention is not limited to the defined interval range, but may be a value of a new interval composed of any two values ​​within the interval, or any one specific value within the interval. For example, in the present invention, "the content of surfactant is 0.05% to 0.1%" means that the content of surfactant is 0.05% to 0.1%. % The range is not limited to a value range of 0.05% to 1% and may be a new range consisting of any two values ​​from the countless values ​​between 0.05% and 1%, such as 0.05% to 0.5%, 0.1% to 0.8%, etc. Furthermore, when there are multiple combinations of values, each parameter can take any value within that range, and the values ​​of multiple parameters can be arbitrarily combined. If the pH value of the polishing liquid is 1 or less and the viscosity of the polishing liquid is 1 to 4 mPa·s, the pH value of the polishing liquid can be any value within the range of 1 or less, and the viscosity of the polishing liquid can be any value within the range of 1 to 4 mPa·s. These two parameters can also be arbitrarily combined, for example, a pH value of 0.1 and a viscosity of 3.5 mPa·s.

[0065] It is to be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "said" are intended to include the plural forms unless the context clearly dictates otherwise. The terms "comprise," "include," "contain," and "have" are inclusive and thus indicate the presence of stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. Method steps, processes, and operations described herein should not be construed as requiring performance in the particular order described or illustrated, unless an order of performance is explicitly indicated. It is also to be understood that additional or alternative steps may be employed.

[0066] In the description herein, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, general expressions using the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine different embodiments or examples described herein, as well as features of different embodiments or examples, without mutual contradictions. [Brief explanation of the drawings]

[0067] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for the purpose of illustrating the preferred embodiments and are not to be construed as limiting the invention. Like parts throughout the drawings are designated by like reference numerals. [Figure 1]FIG. 2 is a view showing the stent of Example 1 magnified 500 times by an SEM scanning electron microscope. [Figure 2] FIG. 2 is a diagram showing the stent of Example 1 magnified 200 times with an optical microscope. [Figure 3] FIG. 2 is a diagram showing the stent of Comparative Example 1 magnified 200 times with an optical microscope. DETAILED DESCRIPTION OF THE INVENTION

[0068] The following are only preferred embodiments of the present invention, and the protection of the present invention is not limited to the following preferred embodiments. For example, although a stent or a specific model of stent is described as an example in all of the examples, the technical solutions of the present invention are not limited to this stent or this specific model of stent. It should be noted that for those skilled in the art, any modifications and improvements made based on the creative concept of the present invention are all within the scope of protection of the present invention. Reagents or equipment used without a manufacturer's name are all ordinary products available on the market.

[0069] Test Method 1. Roughness In the present invention, the surface roughness of the polished part was detected using a SENSOFAR Q-SIX cardiovascular stent detector under an interference lens at a magnification of 400 times and a scanning height of 50 μm.

[0070] 2.Viscosity The polishing solution was poured into a Zahn cup CUP1#, the outflow time t was recorded, and the viscosity of the solution was calculated according to the equation kinematic viscosity = 1.1(t-29)*ρ (ρ is the density of the solution).

[0071] 3. Measurement of stent width and thickness The stent was placed under an optical microscope, observed at a magnification of 100 to 200 times, and its size was measured.

[0072] 4. Depth of the wound The stent was sealed and polished with a polishing machine until the cross section of the stent was exposed, and finally the polished cross section was placed under a metallurgical microscope to measure the depth of the scratches.

[0073] 5. Radial strength Radial strength: In terms of performance testing of luminal stents, the radial strength of the luminal stent was used to apply uniform radial pressure to the stent through the compression module, compressing the stent to produce uniform deformation. The radial strength of the stent was defined as the radial pressure applied when the stent was deformed 10% in the radial direction (outer diameter).

[0074] 6. Hyperextension plasticity A balloon catheter with the appropriate length and outer diameter was selected for the stent. The stent was inflated at a pressure of 6-8 atm and maintained at this pressure for 30 seconds. The entire stent was then observed under a 200x 3D microscope and recorded for cracks or rod fractures. If no cracks or rod fractures were found, the procedure was repeated until cracks or rod fractures were found or the expanded outer diameter of the stent met the acceptable criteria. The observations and records were also recorded.

[0075] 7. Appearance Using a three-dimensional measuring microscope, the gloss and roughness of the outer and inner walls of the entire stent were thoroughly inspected at an appropriate magnification (e.g., 50 to 200 times).

[0076] Example 1 The 30018 stent was cut and ultrasonically cleaned for 2 minutes. The cut stent was then placed in a polishing solution (viscosity 4.0 mPa·s) containing 100 ml of sulfuric acid, 3 g of EDTA, 10 ml of glycerol, 5 g of sodium nitrate, 5 g of sodium silicate, 0.1 ml of phytic acid, 0.05 g of sodium lauryl sulfate, and 50 ml of water. The flow rate of the polishing solution was controlled at 1.0 m / s, and the stent was polished for 3 minutes at 20°C. The stent was then removed, washed, and dried. The dried stents were observed under an optical microscope at 200x magnification, revealing a smooth, shiny surface. Under a scanning electron microscope at 500x magnification, the edges and corners of the stents were rounded, the surface area occupied by scratches was 2%, the maximum scratch depth was 1 μm, the removal depth on one side of the stent rod was 15 μm, the polishing uniformity of the stent was 90%, and the mass loss rate of the stent was 45%. Measurements using a sensofar3D optical profiler revealed that the surface roughness Sa of the stent was 15 nm, the radial strength of the stent was 120 kPa, and no cracks or fractures were observed even after balloon expansion to a diameter of 4.6 mm. Five stents were polished repeatedly, and the RSD of the polished stent quality was less than 1%.

[0077] <Example 2> The 30018 stent was cut and ultrasonically cleaned for 2 minutes. The cut stent was then placed in a polishing solution (viscosity 2.0 mPa·s) containing 100 ml of hydrochloric acid, 5 g of tartaric acid, 10 ml of ethylene glycol, 10 ml of perchloric acid, 5 g of sodium alginate, 0.1 g of sodium phytate, 0.05 g of OP-10, and 50 ml of water. The flow rate of the polishing solution was controlled at 0.8 m / s, and the stent was polished for 3 minutes at 25°C. The stent was then removed, washed, and dried. The dried stent was observed under an optical microscope at 200x magnification, revealing a smooth, shiny surface. Under an SEM at 500x magnification, the edges and corners of the stent were rounded, the surface area occupied by scratches was 2%, the maximum scratch depth was 0.5 μm, the removal depth on one side of the stent rod was 15 μm, the polishing uniformity of the stent was 95%, and the mass loss rate of the stent was 42%. Measurements using a sensofar3D optical profiler revealed that the surface roughness Sa of the stent was 10 nm, the radial strength of the stent was 115 kPa, and no cracks or fractures were observed even after balloon expansion to a diameter of 4.6 mm. Five stents were polished repeatedly, and the RSD of the polished stent quality was less than 1.5%. 。

[0078] Example 3 The 30018 stent was cut and ultrasonically cleaned for 5 minutes. The cut stent was then placed in a polishing solution (viscosity 3.0 mPa·s) containing 100 ml of phosphoric acid, 5 g of disodium EDTA, 10 ml of butanediol, 10 ml of nitric acid, 5 g of sodium silicate, 0.1 ml of tannic acid, 0.05 g of polyethylene glycol, and 50 ml of water. The flow rate of the polishing solution was controlled at 0.5 m / s, and the stent was polished for 3 minutes at 30°C. The stent was then removed, washed, and dried. The dried stents were observed under an optical microscope at 200x magnification, revealing a smooth, shiny surface. Under a scanning electron microscope at 500x magnification, the edges and corners of the stents were rounded, the surface area occupied by scratches was 2%, the maximum scratch depth was 1.5 μm, the removal depth on one side of the stent rod was 15 μm, the polishing uniformity of the stent was 92%, and the mass loss rate of the stent was 45%. Measurements using a sensofar3D optical profiler revealed that the surface roughness Sa of the stent was 20 nm, the radial strength of the stent was 125 kPa, and no cracks or fractures were observed even after balloon expansion to a diameter of 4.6 mm. Five stents were polished repeatedly, and the RSD of the polished stent quality was less than 2%.

[0079] Example 4 The 30018 stent was cut and ultrasonically cleaned for 2 minutes. The cut stent was then placed in a polishing solution (viscosity 1.5 mPa·s) containing 100 ml of hydrochloric acid, 3 g of succinic acid, 10 ml of propylene glycol, 10 ml of hydrogen peroxide, 5 g of sodium silicate, 0.1 g of stearic acid, 0.05 g of sodium dodecyl sulfonate, and 50 ml of water. The flow rate of the polishing solution was controlled at 0.5 m / s, and the stent was polished for 3 minutes at 30°C. The stent was then removed, washed, and dried. The dried stents were observed under an optical microscope at 200x magnification, revealing a smooth, shiny surface. Under a scanning electron microscope (SEM) at 500x magnification, the edges and corners of the stents were rounded, the surface area occupied by scratches was 2%, the maximum scratch depth was 2 μm, the removal depth on one side of the stent rod was 15 μm, the polishing uniformity of the stent was 92%, and the mass loss rate of the stent was 44%. Measurements using a sensofar3D optical profiler revealed that the stent had a surface roughness Sa of 20 nm and a radial strength of 120 kPa. No cracks or fractures were observed after balloon expansion to a diameter of 4.6 mm. No significant changes were observed after 4 weeks of storage. Five stents were polished repeatedly, and the RSD of the polished stent quality was less than 2.5%.

[0080] <Example 5> The 30018 stent was cut and ultrasonically cleaned in 12.5% ​​hydrochloric acid for 2 minutes, and then washed with 100 ml of hydrofluoric acid, 3 g of diethylenetriaminepentamethylenephosphonic acid, 10 ml of cyclohexanol, 10 ml of potassium permanganate, 5 g of sodium alginate, 0.1 g of palmitic acid, and 50 ml of pure water. was prepared by mixing Viscosity 1.0mPas polishing The solution was placed in a low-temperature magnetic tank, and the temperature was set to 30°C and the flow rate of the polishing solution was set to 0.8 mThe stents were polished at 1000 kJ / s in a low-temperature magnetic tank for 3 minutes, then removed, washed, and dried. Observation of the dried stents under an optical microscope at 200x magnification revealed a smooth, shiny surface. Observation under a scanning electron microscope at 500x magnification revealed rounded edges and corners, a scratch area of ​​2% of the surface, a maximum scratch depth of 0.5 μm, a removal depth of 15 μm on one side of the stent rod, a polishing uniformity of 92%, and a mass loss of 46%. Measurements using a sensofar3D optical profiler revealed a surface roughness Sa of 20 nm and a radial strength of 115 kPa. No cracks or fractures were observed even after balloon expansion to a diameter of 4.6 mm. Five stents were polished repeatedly, and the RSD of the polished stent quality was less than 3%.

[0081] Example 6 The 30018 stent was cut and ultrasonically cleaned in 12.5% ​​hydrochloric acid for 2 minutes, followed by a 50 ml solution of 100 ml of perchloric acid, 5 g of sodium gluconate, 10 ml of butanol, 5 g of potassium nitrate, 5 g of sodium alginate, 0.1 g of sodium stearate, 0.05 g of betaine, 0.05 g of sodium lauryl sulfate, and 50 ml of pure water. was prepared by mixing Viscosity 2.5mPas polishing The solution was placed in a low-temperature magnetic tank, and the temperature was set to 25°C and the flow rate of the polishing solution was set to 0.6 mThe stents were polished at 1000 kJ / s in a low-temperature magnetic tank for 3 minutes, then removed, washed, and dried. Observation of the dried stents under an optical microscope at 200x magnification revealed a smooth, shiny surface. Observation under a scanning electron microscope at 500x magnification revealed rounded edges and corners, a scratch area of ​​2% of the surface, a maximum scratch depth of 0.3 μm, a removal depth of 15 μm on one side of the stent rod, a polishing uniformity of 95%, and a mass loss of 43%. Measurements using a sensofar3D optical profiler revealed a surface roughness (Sa) of 12 nm and a radial strength of 118 kPa. No cracks or fractures were observed even after balloon expansion to a diameter of 4.6 mm. Five stents were polished repeatedly, and the RSD of the polished stent quality was less than 3%.

[0082] Example 7 The 30018 stent was cut and ultrasonically cleaned for 2 minutes. The cut stent was then placed in a polishing solution (viscosity 2.5 mPa·s) containing 100 ml of sulfuric acid, 5 g of disodium EDTA, 10 ml of ethylene glycol, 5 g of sodium nitrate, 0.1 ml of phytic acid, and 50 ml of water. The flow rate of the polishing solution was controlled at 0.5 m / s, and the stent was polished for 3 minutes at 25°C. The stent was then removed, washed, and dried. When the dried stent was examined under an optical microscope at 200x magnification, the surface was smooth and shiny. When examined under an SEM at 500x magnification, the edges and corners of the stent were rounded, the percentage of scratched surface area was 2.5%, the maximum scratch depth was 2 μm, the removal depth on one side of the stent rod was 15 μm, the polishing uniformity of the stent was 85%, and the mass loss rate of the stent was 44%. When measured using a sensofar3D optical profiler, the surface roughness Sa of the stent was 18 nm, and the radial strength of the stent was 115 kPa. When expanded to a diameter of 4.5 mm using a balloon, no fracture occurred. Five stents were polished repeatedly, and the RSD of the polished stent quality was less than 3%.

[0083] Example 8 The 30018 stent was cut and ultrasonically cleaned for 2 minutes. The cut stent was then placed in a polishing solution (viscosity 3.5 mPa·s) containing 100 ml of hydrochloric acid, 3 g of succinic acid, 10 ml of glycerol, 10 ml of nitric acid, 5 g of sodium alginate, and 50 ml of water. The flow rate of the polishing solution was controlled at 0.6 m / s, and the stent was polished for 3 minutes at 30°C. The stent was then removed, washed, and dried. The dried stents were observed under an optical microscope at 200x magnification, revealing a smooth, shiny surface. Under a scanning electron microscope at 500x magnification, the edges and corners of the stents were rounded, the surface area occupied by scratches was 2%, the maximum scratch depth was 1.2 μm, the removal depth on one side of the stent rod was 1.5 μm, the polishing uniformity of the stent was 88%, and the mass loss rate of the stent was 48%. Measurements using a sensofar3D optical profiler revealed that the surface roughness Sa of the stent was 25 nm, the radial strength of the stent was 120 kPa, and no cracks or fractures were observed even after balloon expansion to a diameter of 4.6 mm. After 7 days of storage, yellow spots were observed on the surface. Five stents were polished repeatedly, and the RSD of the polished stent quality was less than 2%.

[0084] Example 9 The 30018 stent was cut and ultrasonically cleaned for 2 minutes. The cut stent was then placed in a polishing solution (viscosity 3.5 mPa·s) containing 100 ml of phosphoric acid, 5 g of malic acid, 10 ml of butanediol, 10 ml of perchloric acid, and 50 ml of water. The flow rate of the polishing solution was controlled at 0.8 m / s, and the stent was polished for 3 minutes at 35°C. The stent was then removed, washed, and dried. The dried stents were observed under an optical microscope at 200x magnification, revealing a smooth, shiny surface. Under a scanning electron microscope at 500x magnification, the edges and corners of the stents were rounded, the surface area covered by scratches was 3%, the maximum scratch depth was 2.5 μm, the removal depth on one side of the stent rod was 15 μm, the polishing uniformity of the stent was 82%, and the mass loss rate of the stent was 48%. Measurements using a sensofar3D optical profiler revealed that the surface roughness Sa of the stent was 30 nm, the radial strength of the stent was 128 kPa, and the stent fractured when expanded to a diameter of 4.0 mm using a balloon. Five stents were polished repeatedly, and the RSD of the polished stent quality was less than 1.5%.

[0085] <Comparative Example 1> The 30018 stent was cut and ultrasonically cleaned for 2 minutes, then placed in a polishing solution containing 140 ml of acetic acid and 60 ml of perchloric acid and polished for 20 seconds at a constant current of 0.1 A using a DC power supply. The stent was then removed, washed, and dried. The dried stents were observed under an optical microscope at 200x magnification. The surfaces were smooth and shiny, but the stents were partially yellowed, with small scratches at both ends and large scratches in the center. Observation under an SEM at 500x magnification revealed rounded edges and corners, a 5% surface area ratio with scratches, a maximum scratch depth of 6 μm, a single-sided removal depth of 5 μm on the inner wall of the stent rod, a polishing uniformity of 50%, and a mass loss rate of 50%. Measurements using a sensofar3D optical profiler revealed a surface roughness (Sa) of 200 nm and a radial strength of 95 kPa. The stents fractured when expanded to a diameter of 3.5 mm using a balloon. Five stents were polished repeatedly, and the RSD of the polished stent quality was less than 3%.

[0086] <Comparative Example 2> The 30018 stent was cut and ultrasonically cleaned for 2 minutes. A polishing solution consisting of 60 ml of phosphoric acid, 30 ml of sulfuric acid, and 10 ml of nitric acid was heated to boiling, and the stent was polished in the polishing solution for 10 seconds. The stent was then washed and dried. Observation of the dried stent under an optical microscope at 200x magnification revealed a rough, uneven, and yellowish surface. Observation under an SEM at 500x magnification revealed that the edges and corners of the stent were rounded, with a scratch area of ​​8% and a maximum scratch depth of 0.5 μm. The removal depth on one side of the inner wall of the stent rod was 16 μm. The polishing uniformity of the stent was 90%, and the mass loss rate of the stent was 65%. Measurements using a sensofar3D optical profiler revealed a surface roughness (Sa) of 250 nm and a radial strength of 70 kPa. The stent fractured when expanded to a diameter of 4.0 mm using a balloon. After polishing five consecutive stents repeatedly, the RSD of the polished stent quality exceeded 10%.

[0087] As can be seen from the comparative examples, in the stent subjected to electrochemical polishing in Comparative Example 1, the size of each part varied, the surface was yellowish and rough, the proportion of the surface area occupied by scratches was high, the depth of the scratches was large, and the radial bearing capacity and expansion capacity of the stent were low. In Comparative Example 2, the stent subjected to high-temperature chemical polishing in Comparative Example 2, the surface was yellowish and rough, the proportion of the surface area occupied by scratches was high, and in this method, the polishing time was 10 s is short, the polishing precision of the product is low, and after repeated polishing, the RSD of the size and quality of multiple polished products becomes large, and the polishing stability deteriorates.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although stents are used as examples in the embodiments of the present invention, this does not mean that the present invention is only applicable to the polishing of stents, but also to the polishing of small precision parts of other medical devices and even other non-medical devices. The present invention has been described in detail with reference to the above embodiments, but those skilled in the art may modify the technical solutions described in the above embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention are intended to fall within the scope of protection of the present invention.

Claims

1. A polishing composition comprising an acid, an oxidizing agent, and water, The polishing composition has a pH value of 1 or less, A polishing composition, characterized in that the acid is at least one selected from inorganic acids, and the oxidizing agent is at least one selected from strong inorganic oxidizing agents.

2. 2. The polishing composition according to claim 1, wherein the mass percentage of the inorganic acid is 40% to 70%, and the mass percentage of the inorganic strong oxidizing agent is 5% to 10%.

3. 2. The polishing composition according to claim 1, wherein the polishing composition has a viscosity of 1 mPa s to 4 mPa s.

4. 2. The polishing composition according to claim 1, wherein the inorganic acid is at least one selected from sulfuric acid, phosphoric acid, nitric acid, perchloric acid, and hydrofluoric acid, and the strong inorganic oxidizing agent is at least one selected from persulfates, perchloric acid and its salts, perbromic acid and its salts, periodic acid and its salts, permanganic acid and its salts, peroxides, iodic acid and its salts, chlorous acid and its salts, hypochlorous acid and its salts, hypoiodous acid and its salts, oxybromic acid and its salts, percarbonates, bromic acid and its salts, chloric acid and its salts, hydrogen peroxide, potassium nitrate, and sodium nitrate.

5. 2. The polishing composition according to claim 1, further comprising a thickening agent, the mass percentage of the thickening agent being 1.5% to 7%.

6. 6. The polishing composition according to claim 5, wherein the thickening agent is at least one selected from alcohol, silicic acid, silicates, alginic acid, alginates, polyvinylpyrrolidone, modified organic polyvinylpyrrolidone, ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose, carboxymethyl celluloses, polyacrylic acid, sodium polymethacrylate, sodium polycarboxylate, sodium carboxylate copolymer, carboxylic acid sulfonic acid copolymer, guar gum, sodium starch phosphate, sodium polyacrylate, polyoxyethylenes, carbomer, xanthogenic acid, carrageenan, agar, gelatin, gum arabic and derivatives thereof.

7. The thickening agent comprises at least one component A and at least one component B; Component A is at least one selected from alcohol, ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl celluloses, polyvinylpyrrolidone, polyacrylic acid, sodium polymethacrylate, polycarboxylic acid sodium salts, carboxylic acid sodium salt copolymers, carboxylic acid sulfonic acid copolymers, and derivatives thereof; 6. The polishing composition according to claim 5, wherein component B is at least one selected from the group consisting of silicic acid, silicates, alginic acid, alginates, modified organic substances of polyvinylpyrrolidone, guar gum, sodium starch phosphate, sodium polyacrylate, polyoxyethylenes, carbomer, xanthogenic acid, carrageenan, agar, gelatin, gum arabic, and derivatives thereof.

8. 8. The polishing composition according to claim 7, wherein the mass ratio of component A to component B is 0.5:1 to 15:

1.

9. 2. The polishing composition of claim 1, further comprising a complexing agent, wherein the complexing agent is a monodentate or polydentate ligand, and the complexing agent is at least one selected from amino, carboxyl, cyanide, thiocyanide, isothiocyanide, nitro, hydroxyl, sulfhydryl, aromatic heterocyclic group, nitroso, sulfo, phosphate group, and organophosphino group.

10. 10. The polishing composition of claim 9, wherein the mass percentage of the complexing agent is 0.5% to 2%.

11. 2. The polishing composition according to claim 1, further comprising a surface protective agent, the mass percentage of the surface protective agent being 0.02% to 1%.

12. 12. The polishing composition according to claim 11, wherein the surface protective agent is at least one selected from the group consisting of tannic acid, phytic acid, stearic acid, palmitic acid, and salts thereof.

13. 2. The polishing composition according to claim 1, further comprising a surfactant, the mass percentage of the surfactant being 0.05% to 1%.

14. 14. The polishing composition of claim 13, wherein the surfactant is at least one of an anionic surfactant, a cationic surfactant, a nonionic surfactant, or an amphoteric surfactant, and the surfactant is at least one selected from higher fatty acid salts, alkyl sulfonates, alkyl ether carboxylate surfactants, silicone surfactants, alkane sulfates, substituted amine salts, betaine, lecithin, amino acid derivatives, alkylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ether sodium sulfate, isooctanol polyoxyethylene ethers, alkyl glucosides, and polyoxyethylene ethers.

15. 15. Use of the polishing composition of any one of claims 1 to 14 in polishing a medical device, wherein the medical device comprises an in vivo interventional or implantable device.

16. 16. Use of the polishing composition of claim 15 in polishing a medical device, comprising: The medical device is a degradable metal or metal alloy, and the medical device comprises a vascular stent, a non-intravascular stent, an occluder, a spacer, a vascular prosthesis, a dental implant device, a vascular clamp, a prosthetic heart valve, an orthopedic implant, a dental implant, a respiratory implant, a gynecological implant, a male medical implant, a suture, or a bolt.

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