Metal products, metal product manufacturing method, and water repellent liquid agent

Abstract

To provide a metal product that has low environmental load, is easy to handle, and is high in chemical durability, water repellency, and heat resistance and a method for producing the same.SOLUTION: A metal component has a water-repellent coat formed on all or part of its surface, the water-repellent coat being a resin substantially free of halogen component.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to metal products with good water repellency, a method for manufacturing metal products, and a water repellent liquid agent, and more specifically to metal products on which a water repellent coating containing a silicone-based resin is formed, a method for manufacturing the same, and a water repellent liquid agent containing a silicone-based resin. [Background technology]

[0002] Metal products used in medical equipment and the like are often exposed to chemicals and are therefore required to have chemical durability such as water resistance and alkali resistance.

[0003] Metal products may also be washed using a water jet, detergent, ultrasonic cleaning, etc. They may also be subjected to dry heat sterilization at approximately 300°C. Therefore, it is important that metal products not only have good cleanability, but also do not change, deteriorate, peel, etc., even after undergoing the washing process or dry heat sterilization.

[0004] Patent Document 1 proposes a method for improving the water repellency, water resistance, and alkali resistance of a pharmaceutical container by forming a fluororesin-based water-repellent coating on the surface of the pharmaceutical container.

[0005] Patent Document 2 proposes a method for improving the water repellency of a pharmaceutical container by forming a fluorine-containing water-repellent coating on the surface of the container, and further a method for reducing the amount of Si elution when the container is filled with water and autoclaved. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2013 / 179514 [Patent Document 2] Japanese Patent Application Publication No. 5-132065 Summary of the Invention [Problem to be solved by the invention]

[0007] The surfaces of metal products are highly hydrophilic, so cleaning them takes a long time. In addition, medical instruments used in surgery and other procedures are difficult to clean, so they are disposable, resulting in increased medical costs.

[0008] To solve this problem, it is effective to form a water-repellent coating on the surface of the metal product. However, since the water-repellent coating contains halogen components such as fluorine components, it poses problems in terms of environmental impact and handling.

[0009] Furthermore, metal products are sometimes washed at high temperatures of approximately 200 to 300°C, but the water-repellent coatings described above have low heat resistance and are therefore prone to alteration, deterioration, peeling, and the like at high temperatures.

[0010] Therefore, an object of the present invention is to provide a metal product that has a low environmental impact, is easy to handle, and has high chemical durability, water repellency, and heat resistance, and a method for producing the same, as well as to provide a water repellent liquid agent for obtaining a water repellent coating with high water repellency. [Means for solving the problem]

[0011] The present inventors conducted various experiments and found that the above technical problems can be solved by forming a water-repellent coating containing a resin that does not contain halogen components on the surface of a metal product, and have proposed this finding as the present invention. That is, the metal part of the present invention is a metal part having a water-repellent coating formed on part or all of its surface, characterized in that the water-repellent coating is made of a resin that is substantially free of halogen components. Here, "a water-repellent coating that is substantially free of halogen components" means that the content of halogen components in the water-repellent coating is less than 0.8% by mass.

[0012] In addition, in the metal part of the present invention, it is preferable that the resin is a silicone-based resin, and that the silicone-based resin is an organopolysiloxane compound having organic substituents of methyl and / or phenyl groups. By incorporating such a silicone-based resin into the water-repellent liquid agent, good water repellency can be maintained even when the metal product is washed with detergents of a wide range of pH, and deterioration, peeling, etc. of the water-repellent coating can be suppressed.

[0013] In the metal part of the present invention, the organopolysiloxane compound preferably further has an organic substituent selected from the group consisting of an epoxy group, an ether group, and a polyester group.

[0014] In addition, in the metal part of the present invention, the thickness of the water-repellent coating is preferably 100 to 4000 nm.

[0015] The metal part of the present invention is preferably used in a medical instrument.

[0016] The method for manufacturing a metal part of the present invention is a method for manufacturing a metal part having a water-repellent coating formed on part or all of its surface, and is characterized by comprising the steps of: preparing a metal part; applying a water-repellent liquid agent containing a resin that is substantially free of halogen components and an organic solvent to part or all of the surface of the metal part; and drying and thermally curing the applied water-repellent liquid agent by heat treatment to form a water-repellent coating.

[0017] In the method for producing a metal part of the present invention, the resin is preferably a silicone-based resin, and the silicone-based resin is preferably an organopolysiloxane compound having organic substituents of methyl groups and / or phenyl groups.

[0018] In the method for producing a metal part of the present invention, the water-repellent liquid agent preferably further contains a surface conditioner that reduces surface tension.

[0019] In the method for producing a metal part of the present invention, the thickness of the water-repellent coating is preferably 100 to 4000 nm, which makes it less likely for defects such as pinholes to occur and reduces stress that occurs after thermal curing, thereby preventing deterioration, peeling, etc. of the water-repellent coating.

[0020] In the method for manufacturing a metal part of the present invention, the metal part is preferably a metal part used in a medical instrument.

[0021] The water-repellent liquid agent of the present invention is a water-repellent liquid agent for forming a water-repellent coating on all or part of the surface of a metal part, and is characterized by containing a resin that is substantially free of halogen components.

[0022] Furthermore, in the water-repellent liquid agent of the present invention, the resin is preferably a silicone-based resin, and the silicone-based resin is preferably an organopolysiloxane compound having organic substituents of methyl groups and / or phenyl groups.

[0023] In the water repellent liquid agent of the present invention, the organopolysiloxane compound preferably further has an organic substituent selected from the group consisting of an epoxy group, an ether group, and a polyester group.

[0024] The water-repellent liquid agent of the present invention preferably has a resin content of 10 to 60% by mass, which makes it easier to adjust the viscosity of the water-repellent liquid agent and to make the thickness of the water-repellent coating more uniform.

[0025] The water-repellent liquid agent of the present invention is preferably used for metal parts of medical instruments. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide a metal product that has a low environmental impact, is easy to handle, and has high chemical durability, water repellency, and heat resistance. DETAILED DESCRIPTION OF THE INVENTION

[0027] Preferred embodiments of a metal product and a method for manufacturing the same will be described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments.

[0028] [Water repellent liquid] The water-repellent liquid agent for forming the water-repellent coating contains a resin that is substantially free of halogen components, such as alkylethylene urea resins, alkylketene dimer resins, silicone resins, and pyridinium salt resins. Of these, silicone resins are preferred because of their excellent water repellency and heat resistance.

[0029] The silicone resin preferably contains an organopolysiloxane compound having one or more organic substituents selected from the group consisting of methyl, phenyl, epoxy, ether, and polyester groups in its molecule, and more preferably methyl and / or phenyl groups. By incorporating an organopolysiloxane compound having such organic substituents, the water-repellent coating can maintain good water repellency even when exposed to detergents with a wide range of pH levels at high temperatures for extended periods, while also suppressing deterioration and peeling of the water-repellent coating. Furthermore, a water-repellent coating with high heat resistance and hardness can be obtained.

[0030] Organopolysiloxane compounds contain at least one siloxane structure. The siloxane structure is shown below and may be a composite structure consisting of a single chain, linear, or cage structure, where the side chain R represents a hydrogen atom or a hydrocarbon group. Polymerized siloxanes consisting of oligomeric and polymeric siloxane units with organic side chains (R≠H) are represented as polysiloxanes (SiOR1R2)n (n≧1), where R1 and R2 have one or more organic substituents selected from the group consisting of methyl, phenyl, epoxy, ether, and polyester groups.

[0031] [ka] [ka]

[0032] Representative examples of polysiloxanes are shown below. Methylpolysiloxane: (SiO(CH4)) n (n≧1) Phenylpolysiloxane: (SiO(C6H6)) n (n≧1) Dimethylpolysiloxane: (SiO(CH3)2) n (n≧1) [ka] [ka] [ka]

[0033] The content of the resin in the water-repellent liquid agent, preferably a silicone-based resin, and particularly an organopolysiloxane compound, is preferably 1% or more, 5% or more, 10% or more, and particularly preferably 15% or more by mass, and is preferably 60% or less, 50% or less, 45% or less, and particularly preferably 40% or less. If the resin content is too high, the viscosity of the water-repellent liquid agent increases, making it difficult to apply it to the surface of a metal product with a uniform thickness. As a result, residual stress in the water-repellent coating tends to cause cracking and peeling during drying and thermal curing.

[0034] The organopolysiloxane compound contained in the water-repellent liquid agent preferably contains dimethylpolysiloxane, phenylpolysiloxane, and methylpolysiloxane. The inclusion of these compounds enhances water repellency and temperature stability. When the molar ratio of dimethylpolysiloxane:phenylpolysiloxane:methylpolysiloxane is A:B:C, A is 0.1-4.0, B is 0.1-4.0, and C is 0.1-4.0, preferably A is 0.3-3.0, B is 0.4-2.5, and C is 0.4-2.5, and more preferably A is 0.6-2.0, B is 0.7-1.5, and C is 0.7-1.5. If the mass ratio of the two is outside the above range, it becomes difficult to sufficiently enhance water repellency and heat resistance is impaired.

[0035] The water-repellent liquid agent is preferably applied to the surface of the metal product in a state where it is uniformly mixed with an organic solvent. The organic solvent is not particularly limited, but examples include butyl alcohol, isopropyl alcohol, and isopropyl acetate. These organic solvents may be used in combination, or a single type may be used. The content of the organic solvent in the water-repellent liquid agent is preferably 1% or more, 5% or more, 10% or more, 15% or more, 20% or more, and particularly preferably 25% or more, by mass, and is preferably 80% or less, 60% or less, and particularly preferably 40% or less.

[0036] The water-repellent liquid agent may contain a surface conditioner that adjusts the surface tension. This can improve the smoothness of the water-repellent coating after application to the surface of the metal product. The content of the surface conditioner in the water-repellent liquid agent is, in mass %, preferably 0 to 10%, more preferably 0 to 5%, and particularly 0.5 to 1%.

[0037] The water-repellent liquid agent may further contain an organic acid such as amino acid, citric acid, acetic acid, or oxalic acid. This allows the agent to maintain excellent chemical resistance even in high-pH solutions. A mixture of multiple organic acids may be used, or only one type may be used. The organic acid content in the water-repellent liquid agent is preferably 0.1% or more, 0.5% or more, and particularly 1% or more, by mass, and is preferably 10% or less, 8% or less, 5% or less, and particularly 4% or less. If the organic acid content is too high, the water-repellent liquid agent may corrode the surface of the metal product when applied.

[0038] It is preferable that the water-repellent liquid agent (water-repellent coating) is substantially free of halogen components, particularly fluorine components and chlorine components, which reduces the environmental impact and improves handling.

[0039] The peak intensity of the Raman spectrum of the water-repellent coating is in the wavenumber range of 900 to 1250 cm -1 , 1500~1650cm -1 , 2500~3000cm -1 In each case, it is preferable that the value is 1.1 times or more of the base value when fitting is performed with a Gaussian function. This makes it possible to maintain good water repellency even when washed with detergents of a wide range of pH levels, and to prevent deterioration, peeling, etc. of the water-repellent coating.

[0040] [How to apply water repellent liquid] To ensure that the water-repellent liquid agent is applied uniformly, it is preferable to clean the metal product in advance. The cleaning method is not particularly limited, but may involve removing dust and the like by air blowing, or solvent cleaning with purified water, acetone, or the like.

[0041] The method for applying the water-repellent liquid agent is not particularly specified, and a dipping method, a spray method, an electrostatic spray method, or the like can be applied.

[0042] [Formation of water-repellent coating] After applying the water-repellent liquid agent to the surface of the metal product, it is preferable to dry and heat-cure it by heat treatment to form a water-repellent coating. The drying process is a process of volatilizing the organic solvent in the water-repellent liquid agent. The heat-cure process is a process of causing a dehydration condensation reaction of the water-repellent liquid agent to firmly bond with the surface of the metal product.

[0043] The drying temperature in the drying step is preferably 40°C or higher, 45°C or higher, and particularly preferably 50°C or higher, and is preferably 180°C or lower, 170°C or lower, and particularly preferably 150°C or lower. If the drying temperature is too low, the organic solvent is not sufficiently removed from the water-repellent liquid agent, and the water-repellent coating is likely to become cloudy or peel off. If the drying temperature is too high, a thermosetting reaction occurs, and the water-repellent coating is likely to become cloudy or peel off.

[0044] The drying time is preferably 5 minutes or more, 10 minutes or more, 15 minutes or more, particularly 20 minutes or more, and is preferably 120 minutes or less, 100 minutes or less, particularly 80 minutes or less. If the drying time is too short, the organic solvent is not sufficiently removed from the water-repellent liquid agent, and the water-repellent coating is likely to become cloudy or peel off. If the drying time is too long, the productivity of the metal product decreases.

[0045] The heat curing temperature in the heat curing process is preferably 185°C or higher, 190°C or higher, and particularly 200°C or higher, and preferably 350°C or lower, 325°C or lower, and particularly 300°C or lower. If the heat curing temperature is too low, the heat curing reaction does not occur sufficiently, making it difficult to improve the water repellency of the metal product. On the other hand, if the heat curing temperature is too high, the water repellent liquid agent may thermally decompose, causing defects in the water repellent coating, and in the worst case, the water repellent coating may disappear.

[0046] The heat curing time is preferably 5 minutes or more, 10 minutes or more, and particularly 15 minutes or more, and is preferably 150 minutes or less, 140 minutes or less, and particularly 120 minutes or less. If the heat curing time is too short, the heat curing reaction does not occur sufficiently, making it difficult to improve the water repellency of the metal product. On the other hand, if the heat curing time is too long, the productivity of the metal product decreases.

[0047] The thickness of the water-repellent coating after thermal curing is preferably 100 nm or more, 120 nm or more, 300 nm or more, 500 nm or more, or 520 nm or more, and is preferably 4000 nm or less, 2500 nm or less, 2000 nm or less, and particularly preferably 1500 nm or less. This makes it difficult for defects such as pinholes to occur, and reduces stress that occurs after thermal curing, thereby preventing deterioration, peeling, etc. of the water-repellent coating.

[0048] [Metal products] Various metal materials can be used for the metal parts on which the water-repellent coating is formed, such as SUS, titanium, titanium-nickel alloy, cobalt-chromium alloy, tantalum, and niobium.

[0049] The metal product of the present invention can be used in a variety of applications, for example, as forceps for endoscopes, metal tubes for catheters, and the like, which are expected to be washed and reused repeatedly. [Example]

[0050] The present invention will be described in detail based on examples. Note that the following examples are merely illustrative and the present invention is not limited to the following examples.

[0051] [Sample No. 1] A water-repellent liquid agent was prepared by mixing and dissolving 30% by mass of an organopolysiloxane compound (silicone resin) containing methyl groups and phenyl groups, 15% by mass of butyl alcohol, 10% by mass of isopropyl acetate, and 45% by mass of isopropyl alcohol, and then adding 2% by mass of citric acid, mixing, and dissolving. The dimethylpolysiloxane, phenylpolysiloxane, and methylpolysiloxane were adjusted to a molar ratio of 1.3:1:1.

[0052] The water-repellent liquid was applied to a SUS substrate by spin coating. The glass substrate with the water-repellent liquid applied was dried for 60 minutes in a dryer heated to 60°C. Next, a heat curing treatment was performed for 60 minutes in a dryer heated to 210-225°C, forming a water-repellent coating 1500 nm thick on the surface of the SUS substrate.

[0053] The contact angle of a water droplet on the SUS substrate after the heat curing treatment was measured using a contact angle measuring instrument (B100 manufactured by Asumi Giken) and purified water, and the contact angle was found to be 88.7°.

[0054] [Sample No. 2] A water-repellent liquid was prepared by mixing and dissolving 30% by weight of a methyl-containing organopolysiloxane compound (silicone resin), 15% by weight of butyl alcohol, 10% by weight of isopropyl acetate, and 45% by weight of isopropyl alcohol, and then adding 2% by weight of citric acid, mixing, and dissolving. The molar ratio of dimethylpolysiloxane and methylpolysiloxane contained in the organopolysiloxane compound was adjusted to 1.3:1.0.

[0055] The water-repellent liquid was applied to a SUS substrate by spin coating. The glass substrate with the water-repellent liquid applied was dried for 60 minutes in a dryer heated to 60°C. Next, a heat curing treatment was performed for 60 minutes in a dryer heated to 210-225°C, forming a water-repellent coating 1500 nm thick on the surface of the SUS substrate.

[0056] The contact angle of a water droplet on the SUS substrate after the heat curing treatment was measured using a contact angle measuring instrument (B100 manufactured by Asumi Giken) and purified water, and the contact angle was found to be 85.7°.

[0057] [Chemical durability evaluation] The SUS substrates with water-repellent coatings of Samples No. 1 and 2 were washed three times each with purified water, and then immersed in a sodium hydroxide solution adjusted to a pH of 11. After that, they were heat-treated at 121°C for 60 minutes, and then, with the water-repellent coating still immersed in the solution, they were held up to a light source such as a fluorescent lamp to check for cracks or peeling in the water-repellent coating, and no cracks or peeling were found.

[0058] The SUS substrates with water-repellent coatings of Samples No. 1 and 2 were washed three times each with purified water and then immersed in a hydrochloric acid solution adjusted to pH 4. After that, they were heat-treated at 121°C for 60 minutes, and then the substrates, with the water-repellent coating still immersed in the solution, were held up to a light source such as a fluorescent lamp to check for cracks or peeling in the water-repellent coating, and no cracks or peeling were found.

[0059] [Heat resistance evaluation] The SUS substrates with the water-repellent coatings of Samples No. 1 and 2 were subjected to a heat treatment at 300° C. for 60 minutes, and then the contact angle with a water droplet was measured. No decrease in the contact angle was observed.

[0060] [Sample No. 3] When the same SUS substrate as Sample No. 1 was used and no water-repellent coating was formed, the contact angle of a water droplet was measured, and the contact angle was 64.7°.

[0061] As can be seen from the above, Samples Nos. 1 and 2 had better water repellency, heat resistance up to at least 300° C., and chemical durability than Sample No. 3.

Claims

1. A metal part having a water-repellent coating formed on a part or all of its surface, The water-repellent coating is made of a resin that is substantially free of halogen components, the resin is a silicone-based resin, and the silicone-based resin is an organopolysiloxane compound having organic substituents of methyl groups and / or phenyl groups; the organopolysiloxane compound further has an organic substituent selected from the group consisting of an epoxy group, an ether group, and a polyester group; Metal parts used in medical equipment.

2. 2. The metal part according to claim 1, wherein the water-repellent coating has a thickness of 100 to 4000 nm.

3. A method for manufacturing a metal part having a water-repellent coating formed on a part or all of its surface, comprising: Providing a metal part; A step of applying a water-repellent liquid agent containing a resin that is substantially free of halogen components and an organic solvent to a part or all of the surface of a metal part; a step of drying and thermally curing the applied water-repellent liquid agent by heat treatment to form a water-repellent coating; Equipped with the resin is a silicone-based resin, and the silicone-based resin is an organopolysiloxane compound having organic substituents of methyl groups and / or phenyl groups; The water-repellent liquid agent further contains a surface conditioner that reduces surface tension, A method for manufacturing a metal part, wherein the metal part is a metal part used in a medical device.

4. The method for manufacturing a metal part according to claim 3, wherein the water-repellent coating has a thickness of 100 to 4000 nm.

5. A water-repellent liquid agent for forming a water-repellent coating on all or part of the surface of a metal part, Contains a resin that is substantially free of halogen components, the resin is a silicone-based resin, and the silicone-based resin is an organopolysiloxane compound having organic substituents of methyl groups and / or phenyl groups; the organopolysiloxane compound further has an organic substituent selected from the group consisting of an epoxy group, an ether group, and a polyester group; A water-repellent liquid agent used on metal parts of medical equipment.

6. 6. The water-repellent liquid agent according to claim 5, wherein the resin content is 10 to 60% by mass.

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