Coating composition, coating film, and elongated medical device

Abstract

Provided is a coating composition containing a fluororesin, an engineering plastic (excluding the fluororesin), and a solvent, wherein the solvent contains a high-boiling-point low-polarity organic solvent that has a solubility parameter (SP value) of 9.2 (cal / cm3)1 / 2 or less as calculated by the equation of Fedors and a boiling point of 145°C or more. The coating composition makes it possible to achieve excellent sliding properties.

Description

Coating composition, coating film and long medical device

[0001] The present invention relates to coating compositions that can be used in the manufacture of elongated medical devices such as guidewires.

[0002] Patent Document 1 discloses a guidewire manufactured using a fluororesin, with the aim of achieving excellent lubricity as one of its objectives. In particular, the Examples section of Patent Document 1 discloses that the guidewire is manufactured by sequentially forming a lower layer and a surface layer containing a fluororesin on the surface of a stainless steel wire.

[0003] JP 2015-100664 A

[0004] In a guidewire provided with a coating film containing a fluororesin as disclosed in Patent Document 1, the action of the fluororesin can reduce friction between the surface of the guidewire and the inside of the catheter when the guidewire is inserted into the catheter, thereby making it easier for the guidewire to slide inside the catheter.

[0005] An object of the present invention is to provide a coating composition that can achieve excellent sliding properties.

[0006] In order to achieve the above object, first, the present invention provides a method for producing a polymeric composition comprising a fluororesin, an engineering plastic (excluding the fluororesin), and a solvent, the solvent having a solubility parameter (SP value) calculated by the Fedors equation of 9.2 (cal / cm ３ ) １／２ The present invention provides a coating composition containing a high-boiling, low-polarity organic solvent having a molecular weight of 100 or less and a boiling point of 145°C or higher (Invention 1).

[0007] In the above invention (Invention 1), it is preferable that the high-boiling-point, low-polarity organic solvent has a surface tension of 30 dyn / cm or less, and that the solvent contains, together with the high-boiling-point, low-polarity organic solvent, a second solvent having a surface tension of more than 30 dyn / cm (Invention 2).

[0008] In the above inventions (Inventions 1 and 2), it is preferable that the high-boiling, low-polarity organic solvent is blended in the coating composition in an amount of 5 to 50 parts by mass per 100 parts by mass of the fluororesin (Invention 3).

[0009] In the above inventions (Inventions 1 to 3), the high-boiling, low-polarity organic solvent is preferably at least one selected from the group consisting of aliphatic hydrocarbons having 9 to 20 carbon atoms, aromatic hydrocarbons having 9 to 20 carbon atoms, diethylene glycol monobutyl ether, propylene glycol methyl ether, coal tar naphtha, 3-methoxy-3-methylbutyl acetate, and triethylene glycol monobutyl ether (Invention 4).

[0010] Secondly, the present invention provides a coating film, which preferably contains a fluororesin and an engineering plastic (excluding the fluororesin), and has a fluorine concentration of 65 mass% or more when measured on the film surface (Invention 5).

[0011] Third, the present invention provides a long medical device having, on its surface, a coating film obtained by applying the coating composition according to any one of the above inventions (1) to (4) or the coating film according to the above invention (5) (Invention 6).

[0012] Hereinafter, an embodiment of the present invention will be described. The coating composition according to this embodiment contains a fluororesin, an engineering plastic (excluding the above-mentioned fluororesin), and a solvent. The solvent has a solubility parameter (SP value) calculated by the Fedors equation of 9.2 (cal / cm ３ ) １／２ The organic solvent used in the present invention is a high-boiling, low-polarity organic solvent having a boiling point of 145°C or higher.

[0013] The coating composition according to this embodiment has the above-mentioned composition, and in particular contains the above-mentioned high-boiling, low-polarity organic solvent, so that the fluororesin tends to be localized on the surface side of the coating film formed using the coating composition. The surface side here refers to the side of the coating film formed opposite to the target when the coating composition is applied to the target.

[0014] As described above, the surface of the formed coating film exhibits excellent sliding properties due to the fluororesin being localized on the surface side, and the action of the fluororesin is effectively exerted. Therefore, when a coating film is formed on the surface of a long medical device such as a guidewire using the coating composition according to this embodiment, the long medical device will have excellent sliding properties.

[0015] Furthermore, since the fluororesin is localized on the surface side of the coating film, the engineering plastic tends to be localized relatively closer to the object to be coated, thereby improving the adhesion between the coating film and the object to be coated.

[0016] As described above, the reason why the fluororesin tends to localize on the surface side of the coating film is thought to be, but is not limited to, the following: First, the high-boiling-point, low-polarity organic solvent has a relatively low surface tension, which causes it to localize on the surface side when a coating film is formed. Second, since both the high-boiling-point, low-polarity organic solvent and the fluororesin have low polarity, they have a high affinity, and the fluororesin also localizes on the surface side together with the high-boiling-point, low-polarity organic solvent.

[0017] Furthermore, due to their high boiling points, high-boiling, low-polarity organic solvents are more likely to remain in the coating film than other solvents. Therefore, when the solvent in the coating film is evaporated, the high-boiling, low-polarity organic solvent remains in the coating film until the end, making it easier for the fluororesin to maintain a localized state. Furthermore, when the coating film is baked to form a coating film, the fluidity of the coating film is temporarily restored by heating, but the action of the small amount of remaining high-boiling, low-polarity organic solvent maintains the localized state of the fluororesin.

[0018] As a result, the fluororesin is sufficiently localized on the surface side of the formed coating film, and as a result, the long medical device provided with this coating film exhibits excellent sliding properties.

[0019] 1. Components of the Coating Composition (1) Fluorine Resin In this embodiment, known fluororesins can be used. Suitable examples of fluororesins include polytetrafluoroethylene (hereinafter sometimes referred to as "PTFE"), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (hereinafter sometimes referred to as "PFA"), tetrafluoroethylene-hexafluoropropylene copolymer (hereinafter sometimes referred to as "FEP"), polychlorotrifluoroethylene (hereinafter sometimes referred to as "PCTFE"), and the like. Among these, it is preferable to use PTFE from the viewpoint of easily achieving excellent sliding properties.

[0020] The coating composition according to this embodiment preferably contains 0.1 to 40% by mass of the fluororesin, and from the viewpoint of making it easier to achieve better sliding properties, the content of the fluororesin in the coating composition is more preferably 1 to 30% by mass, and particularly preferably 5 to 25% by mass.

[0021] (2) Engineering Plastics (excluding Fluorine Resins) In this embodiment, known engineering plastics can be used. Examples of engineering plastics include super engineering plastics such as polysulfone resins (e.g., polyethersulfone, etc.), polyamideimide, aromatic polyetherketone resins (e.g., polyetherketone, polyetheretherketone, polyetherketoneketone), polyphenylene sulfide, liquid crystal polymers, polyetherimide, polyimide, polyarylate, and polyethernitrile, as well as engineering plastics other than super engineering plastics such as polycarbonate, polyamide, polybutylene terephthalate, polyacetal, modified polyphenylene ether, and polyethylene terephthalate.

[0022] Among these, from the viewpoint of easily achieving excellent sliding properties, the SP value is preferably 9.3 or more, more preferably 10.0 or more, and even more preferably 11.0 or more. From the viewpoint of easily achieving even better sliding properties, at least one selected from the group consisting of polysulfone resin, aromatic polyether ketone resin, and polyamide imide is more preferred, and from the viewpoint of easily achieving excellent adhesion to the substrate and even better sliding properties, polysulfone resin is even more preferred.

[0023] (2-1) Polysulfone Resin The polysulfone resin in this embodiment has a repeating structure containing sulfonyl groups in the constituent molecules, and known polysulfones can be used. Among them, polyethersulfones can be mentioned, and polyethersulfones have the following basic skeleton: The polyethersulfone in this embodiment may be composed solely of the above structure, or may be one in which the above structure is partially modified. An example of such modification is one in which any hydrogen atom on the benzene ring is modified with a sulfone group or the like.

[0024] (2-2) Aromatic Polyetherketone Resin As the polyetherketone resin in the present embodiment, known polyetherketones, polyetheretherketones, polyetherketoneketones, etc. can be used. (2-3) Polyamideimide As the polyamideimide in the present embodiment, known polyamideimides can be used, and the polyamideimide is a resin having both an imide bond and an amide bond.

[0025] (2-4) Amount of Blend The coating composition according to this embodiment preferably contains 0.1 to 40% by mass of the engineering plastic as described above. From the viewpoint of making it easier to improve the adhesion between the coating film to be formed and the surface of the coating target, the content of the engineering plastic in the coating composition is more preferably 1 to 30% by mass, and particularly preferably 5 to 25% by mass.

[0026] (3) Solvent The solvent in this embodiment includes a high-boiling, low-polarity organic solvent as described above. The solvent in this embodiment may also include a solvent other than the high-boiling, low-polarity organic solvent, in addition to the high-boiling, low-polarity organic solvent.

[0027] (3-1) High-Boiling-Point, Low-Polarity Organic Solvent The high-boiling-point, low-polarity organic solvent in this embodiment is a solvent having an SP value of 9.2 (cal / cm ３ ) １／２ There are no particular limitations on the solvent, as long as it satisfies the conditions of a temperature of 100° C. or lower and a boiling point of 145° C. or higher.

[0028] In the present disclosure, the SP value is calculated using the following Fedors equation. δ: solubility parameter (SP value) Δei: evaporation energy of each atom or atomic group Δvi: molar volume of each atom or atomic group

[0029] Examples of high-boiling, low-polarity solvents, from the viewpoint of facilitating improved adhesion between the coating film to be formed and the surface of the coating target, include at least one selected from the group consisting of aliphatic hydrocarbons having 9 to 20 carbon atoms, aromatic hydrocarbons having 9 to 20 carbon atoms, diethylene glycol monobutyl ether, propylene glycol methyl ether, coal tar naphtha, 3-methoxy-3-methylbutyl acetate, and triethylene glycol monobutyl ether.

[0030] Examples of the aliphatic hydrocarbon having 9 to 20 carbon atoms include at least one selected from the group consisting of n-nonane, n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, and n-icosane.

[0031] Examples of the aromatic hydrocarbon having 9 to 20 carbon atoms include at least one selected from the group consisting of 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, n-propylbenzene, isopropylbenzene, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, 1,2,3,4-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, diethylbenzene, and cymene.

[0032] Among the above, it is preferable to use coal tar naphtha, from the viewpoint that it is easy to efficiently cause localization of the fluororesin.

[0033] The SP value of the high-boiling, low-polarity solvent is 9.2 (cal / cm) as described above. ３ ) １／２ However, from the viewpoint of easily localizing the fluororesin more efficiently, it is preferable that the viscosity is 9.0 (cal / cm ３ ) １／２ It is preferable that the calorie content is 8.5 (cal / cm ３ ) １／２ The lower limit of the SP value is not particularly limited, and is, for example, 4.0 (cal / cm ３ ) １／２ It may be 5.0 (cal / cm ３ ) １／２ It may be more than that.

[0034] The boiling point of the high-boiling-point, low-polarity solvent must be 145° C. or higher as described above, but from the viewpoint of more efficiently localizing the fluororesin, it is preferably 150° C. or higher, more preferably 160° C. or higher, and particularly preferably 170° C. or higher. The upper limit of the boiling point is not particularly limited, and may be, for example, 400° C. or lower, particularly 350° C. or lower.

[0035] Furthermore, from the viewpoint of easily and efficiently localizing the fluororesin, the surface tension of the high-boiling-point, low-polarity solvent is preferably 30 dyn / cm or less, particularly preferably 28 dyn / cm or less, and even more preferably 25 dyn / cm or less. The lower limit of the surface tension is not particularly limited, and may be, for example, 5 dyn / cm or more, particularly 10 dyn / cm or more.

[0036] (3-2) Second Solvent The solvent in this embodiment has an SP value of 9.3 (cal / cm ３ ) １／２ It is also preferable that the second solvent contains a second solvent having an SP value of 9.5 (cal / cm ３ ) １／２ In the second solvent, the upper limit of the SP value is not particularly limited, and is, for example, 25.0 (cal / cm ３ ) １／２ It may be equal to or less than 24.0 (cal / cm ３ ) １／２ Examples of the second solvent include at least one selected from the group consisting of N-methylpyrrolidone (hereinafter sometimes referred to as "NMP"), propylene glycol monomethyl ether acetate (hereinafter sometimes referred to as "PMA"), cyclohexanone, 3-methoxy-3-methylbutyl acetate, dimethyl sulfoxide, N,N-dimethylformamide, dimethylacetamide, 2-propanol, xylene, and toluene.

[0037] Furthermore, it is also preferable that the second solvent is different from the high-boiling, low-polarity solvent and has a surface tension of more than 30 dyn / cm. In particular, it is preferable to use a second solvent having a surface tension of more than 30 dyn / cm together with a high-boiling, low-polarity solvent having a surface tension of 30 dyn / cm or less. In this case, in the coating film formed by applying the coating composition according to this embodiment, the high-boiling, low-polarity solvent tends to migrate more efficiently to the surface side, and as a result, it becomes easier to generate localized fluororesin more efficiently. From this viewpoint, the surface tension of the second solvent is more preferably 35 dyn / cm or more, and particularly preferably 40 dyn / cm or more. Surface tension of more than 30 dyn / cm

[0038] Furthermore, it is also preferable to use a solvent having an SP value of 9.3 or more and a boiling point of 145°C or more (hereinafter sometimes referred to as a "high-boiling-point, highly polar solvent"). By using a high-boiling-point, highly polar solvent in combination with a high-boiling-point, low-polarity solvent, the high-boiling-point, low-polarity solvent can more efficiently migrate to the surface side in the coating film formed by applying the coating composition according to this embodiment, and as a result, localization of the fluororesin can be more efficiently achieved. An example of a high-boiling-point, highly polar solvent is NMP.

[0039] The solvent in this embodiment may contain a solvent other than the high-boiling-point, low-polarity solvent and the second solvent, and examples of the solvent other than the high-boiling-point, low-polarity solvent and the second solvent include butyl acetate, methyl isobutyl ketone, and methyl ethyl ketone.

[0040] (3-3) Amount of Blend The coating composition according to this embodiment preferably contains 20 to 99.8% by mass of the solvent. From the viewpoint of making it easier to more efficiently localize the fluororesin, the content of the solvent in the coating composition is more preferably 40 to 90% by mass, and particularly preferably 50 to 90% by mass.

[0041] Furthermore, from the viewpoint of more efficiently causing localization of the fluororesin, the high-boiling, low-polarity organic solvent is preferably blended into the coating composition in an amount of 5 to 50 parts by mass per 100 parts by mass of the fluororesin, more preferably 7.5 to 40 parts by mass per 100 parts by mass of the fluororesin, and even more preferably 10 to 30 parts by mass per 100 parts by mass of the fluororesin.

[0042] Furthermore, when the solvent in this embodiment includes a second solvent, the coating composition preferably includes 40 to 440 parts by mass of the second solvent per 100 parts by mass of the high-boiling, low-polarity organic solvent, more preferably 140 to 350 parts by mass, and even more preferably 150 to 270 parts by mass of the second solvent, which makes it easier to more efficiently localize the fluororesin.

[0043] (4) Other Components The coating composition according to this embodiment may contain components other than the above-mentioned fluororesin, engineering plastic, and solvent. Such other components include those generally added to coating compositions containing fluororesin, specifically fluorine-containing surfactants, silicone surfactants, nonionic surfactants, anionic surfactants, cationic surfactants, thickeners, antifoaming agents, surface conditioners, emulsifiers, antifouling agents, wetting agents, scratch resistance improvers, gloss adjusters such as silica, extender pigments, anticorrosive pigments, coloring pigments, fatty acids, unsaturated fatty acids, and oils and fats. Among these, it is preferable to use fluorine-containing surfactants from the viewpoint of easily achieving better sliding properties.

[0044] When a fluorine-containing surfactant is used, the content of the fluorine-containing surfactant in the coating composition is preferably 0.1 to 10 mass %, particularly preferably 0.5 to 5 mass %, from the viewpoint of making it easier to achieve better sliding properties.

[0045] 2. Method for preparing coating composition The coating composition according to this embodiment can be obtained by appropriately mixing the fluororesin, engineering plastic, and solvent, as well as other components as necessary. Specific methods for this preparation can be known.

[0046] In particular, when powdered PTFE is used as the fluororesin, it is preferable to premix the other components, add the powdered PTFE thereto, and then thoroughly stir to disperse it.

[0047] 3. Coating Film The coating film according to this embodiment contains a fluororesin and an engineering plastic (excluding the above-mentioned fluororesin), and the fluorine concentration measured at the film surface is higher than the fluorine concentration measured at a height of one-seventh of the film thickness from the bottom surface of the film.

[0048] The coating film according to this embodiment preferably has a fluorine concentration of 65% by mass or more, more preferably 70% by mass or more, when measured at the film surface, from the viewpoint of being likely to have better sliding properties. Also, from the viewpoint of having better adhesion to the substrate, the fluorine concentration measured at a position one-seventh of the film thickness from the bottom surface is preferably 30% by mass or less, more preferably 20% by mass or less.

[0049] The fluororesin and engineering plastic contained in the coating film according to this embodiment can be the same as those previously described as components contained in the paint composition according to this embodiment. In particular, it is preferable that the coating film according to this embodiment be formed using the paint composition according to this embodiment. By forming a coating film using the paint composition according to this embodiment, the fluororesin is localized on the surface, making it easy to form a coating film in which the fluorine concentration measured at the film surface is higher than the fluorine concentration measured at a position one-seventh of the film thickness from the bottom.

[0050] The coating film according to this embodiment does not refer to a film of two or more layers formed from two or more types of paint, but rather to a film of one layer formed from one type of paint composition.

[0051] The thickness of the coating film according to this embodiment can be set appropriately depending on the purpose and the object, but is preferably, for example, 2 μm or more and 30 μm or less, and particularly preferably 3 μm or more and 20 μm or less.

[0052] 4. Long Medical Devices The coating composition according to this embodiment is suitable for use in forming a coating film on the surface of a predetermined object. In particular, the coating composition according to this embodiment is suitable for use in applying to the surface of a long medical device, thereby forming a coating film on the surface.

[0053] The method for applying the coating composition according to this embodiment is not particularly limited, and examples thereof include a method of immersing the object in the coating composition, a method of spraying the coating composition onto the object, and a method of spreading the coating composition over the object using a spatula, roller, or the like.

[0054] The thickness of the coating film formed using the coating composition according to this embodiment can be set appropriately depending on the purpose and the object, but is preferably, for example, from 2 μm to 30 μm, and particularly preferably from 3 μm to 20 μm.

[0055] Examples of elongated medical devices include guidewires such as spring guidewires, etc. Such guidewires can also be used as tapered wires and support wires.

[0056] The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0057] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0058] [Materials] As the fluororesin, polytetrafluoroethylene (PTFE) powder was prepared. As polyethersulfone (hereinafter sometimes referred to as "PES"), "Sumikaexcel 4100G" manufactured by Sumitomo Chemical Co., Ltd. was prepared. As the fluorosurfactant, a PTFE-dispersible fluorosurfactant was prepared. As the high-boiling-point, low-polarity organic solvent, coal tar naphtha was prepared. As solvents (second solvents) other than the high-boiling-point, low-polarity organic solvent, N-methyl-2-pyrrolidone (NMP), propylene glycol monomethyl ether acetate (PMA), cyclohexanone, and butyl acetate were prepared.

[0059] The SP values, boiling points, and surface tensions of the high-boiling-point, low-polarity organic solvents and second solvents, as well as common solvents, are summarized in Table 1. In cases where the boiling point ranges, such as coal tar naphtha, the average of the lower and upper limits of the boiling point range is reported as the boiling point.

[0060] In Table 1, the details of the abbreviations of the solvents given as examples of "common solvents" are as follows: MIBK: methyl isobutyl ketone IPA: isopropyl alcohol THF: tetrahydrofuran

[0061]

[0062] Example 1 (1) Preparation of Coating Composition 10.0 g of PES and 38.0 g of NMP were added to a 200 ml stainless steel container, and the mixture was stirred at 1000 rpm using a standard tornado mixer (manufactured by AS ONE Corporation, product name "SM-104") to dissolve the PES in the NMP.

[0063] Next, 4.0 g of coal tar naphtha, 8.0 g of PMA, 8.0 g of cyclohexanone, 17.0 g of butyl acetate, and 3.0 g of fluorine-containing surfactant were added to the resulting solution and stirred at 1000 rpm. 12.0 g of powdered PTFE was then added and dispersed by stirring at 400 rpm for 120 minutes to obtain a coating composition. The composition of the coating composition is as shown in Table 2.

[0064] (2) Preparation of a guide wire with a coating film A stainless steel guide wire with a diameter of 0.34 mm was immersed in the coating composition, then immediately removed and allowed to stand for 10 minutes, thereby forming a coating film of the coating composition on the surface of the guide wire.

[0065] The guidewire with the coating film formed thereon was then baked in a gas oven at 360°C for 60 minutes to obtain a guidewire with a coating film containing PTFE. The thickness of the formed coating film was measured using a micrometer (manufactured by Mitutoyo Corporation, product name "Digimatic Standard Outside Micrometer MDC-25SX") and found to be 7 µm. The adhesion of the coating film was evaluated by a scratch test, and the base material of the guidewire was not visible to the naked eye, indicating good adhesion.

[0066] Example 2 10.0 g of PES and 38.0 g of NMP were added to a 200 ml stainless steel container, and the mixture was stirred at 1000 rpm using a standard tornado mixer (manufactured by AS ONE Corporation, product name "SM-104") to dissolve the PES in the NMP.

[0067] Next, 4.0 g of coal tar naphtha, 33.0 g of butyl acetate, and 3.0 g of fluorine-containing surfactant were added to the resulting solution and stirred at 1000 rpm. 12.0 g of powdered PTFE was then added and dispersed by stirring at 400 rpm for 120 minutes to obtain a coating composition. The composition of the coating composition is as shown in Table 2.

[0068] Furthermore, except that the coating composition obtained above was used, a guide wire having a coating film containing PTFE formed thereon was obtained in the same manner as in Example 1. The adhesion of the coating film was evaluated by a scratch test, and the result showed good adhesion.

[0069] Example 3 10.0 g of PES and 38.0 g of NMP were added to a 200 ml stainless steel vessel, and the mixture was stirred at 1000 rpm using a standard tornado mixer (manufactured by AS ONE Corporation, product name "SM-104") to dissolve the PES in the NMP.

[0070] Next, 4.0 g of coal tar naphtha, 16.0 g of cyclohexanone, 17.0 g of butyl acetate, and 3.0 g of fluorine-containing surfactant were added to the resulting solution and stirred at 1000 rpm. 12.0 g of powdered PTFE was then added and dispersed by stirring at 400 rpm for 120 minutes to obtain a coating composition. The composition of the coating composition is as shown in Table 2.

[0071] Furthermore, except that the coating composition obtained above was used, a guide wire having a coating film containing PTFE formed thereon was obtained in the same manner as in Example 1. The adhesion of the coating film was evaluated by a scratch test, and the result showed good adhesion.

[0072] Comparative Example 1: 10.0 g of PES and 42.0 g of NMP were added to a 200 ml stainless steel container, and the mixture was stirred at 1000 rpm using a standard tornado mixer (manufactured by AS ONE Corporation, product name "SM-104") to dissolve the PES in the NMP.

[0073] Next, 8.0 g of PMA, 8.0 g of cyclohexanone, 17.0 g of butyl acetate, and 3.0 g of fluorine-containing surfactant were added to the resulting solution and stirred at 1000 rpm. 12.0 g of powdered PTFE was then added and dispersed by stirring at 400 rpm for 120 minutes to obtain a coating composition. The composition of the coating composition is as shown in Table 2.

[0074] Furthermore, a guide wire having a coating film containing PTFE formed thereon was obtained in the same manner as in Example 1, except that the coating composition obtained as described above was used.

[0075] Comparative Example 2: 10.0 g of PES and 42.0 g of NMP were added to a 200 ml stainless steel container, and the mixture was stirred at 1000 rpm using a standard tornado mixer (manufactured by AS ONE Corporation, product name "SM-104") to dissolve the PES in the NMP.

[0076] Next, 33.0 g of butyl acetate and 3.0 g of fluorine-containing surfactant were added to the resulting solution and stirred at 1000 rpm. 12.0 g of powdered PTFE was then added and dispersed by stirring at 400 rpm for 120 minutes to obtain a coating composition. The composition of the coating composition is as shown in Table 2.

[0077] Furthermore, a guide wire having a coating film containing PTFE formed thereon was obtained in the same manner as in Example 1, except that the coating composition obtained as described above was used.

[0078] Comparative Example 3: 10.0 g of PES and 42.0 g of NMP were added to a 200 ml stainless steel vessel, and the mixture was stirred at 1000 rpm using a standard tornado mixer (manufactured by AS ONE Corporation, product name "SM-104") to dissolve the PES in the NMP.

[0079] Next, 16.0 g of cyclohexanone, 17.0 g of butyl acetate, and 3.0 g of fluorine-containing surfactant were added to the resulting solution and stirred at 1000 rpm. 12.0 g of powdered PTFE was then added and dispersed by stirring at 400 rpm for 120 minutes to obtain a coating composition. The composition of the coating composition is as shown in Table 2.

[0080] Furthermore, a guide wire having a coating film containing PTFE formed thereon was obtained in the same manner as in Example 1, except that the coating composition obtained as described above was used.

[0081] Test Example 1 (Catheter Sliding Test) The guidewires with coating films manufactured in the Examples and Comparative Examples were passed through a catheter with an inner diameter of 0.44 mm (product name "ASAHI Corsair Pro XS", manufactured by Asahi Intecc Co., Ltd.) with the tip of the guidewire protruding 10 mm from the tip of the catheter.

[0082] The guidewire was then reciprocated 30 times at a speed of 600 mm / min over a distance of 10 mm. The load (gf) generated at the 30th retraction was measured using a compression / tension load cell. The maximum load (gf) obtained is shown in Table 2.

[0083]

[0084] As can be seen from Table 2, the guide wires according to Examples 1 to 3, which had coating films formed using a coating composition containing coal tar naphtha (i.e., a high-boiling, low-polarity organic solvent), had superior catheter slidability compared to Comparative Examples 1 to 3.

[0085] Furthermore, for a guide wire having a coating film formed using the coating composition of Example 1, a blade was inserted at an angle of 15° relative to the coating film surface, and the coating film was peeled off obliquely from the substrate. Subsequently, composition analysis was performed using an EDX attached to a scanning electron microscope at an acceleration voltage of 5 kV and a magnification of 300x, revealing a fluorine concentration of 77.8% by mass. Composition analysis of the surface at a thickness of 1 / 7 of the film thickness from the bottom of the film revealed a fluorine concentration of 11.2% by mass. This confirmed that the fluororesin was localized on the surface side of the film and decreased on the bottom side. Other conditions for the scanning electron microscope and EDX were as follows: Electron gun settings: L.C.: 66 μA; Heating setting (°C): 160; Bias adjustment (COARESE): 832; Bias adjustment (FINE): 168; Element distribution conditions: Process time: T4; Number of pixels: 1024 x 768

[0086] The coating composition of the present invention can be suitably used in the production of long medical devices such as guidewires.

Claims

1. A method for producing a liquid crystal display device comprising: a fluororesin; an engineering plastic (excluding the fluororesin); and a solvent, wherein the solvent has a solubility parameter (SP value) calculated by the Fedors equation of 9.2 (cal / cm ３ ) １／２ A coating composition comprising a high-boiling, low-polarity organic solvent having a boiling point of 145°C or higher and a viscosity of 1000 psi or lower.

2. The coating composition of claim 1, wherein the high-boiling, low-polarity organic solvent has a surface tension of 30 dyn / cm or less, and the solvent contains, together with the high-boiling, low-polarity organic solvent, a second solvent having a surface tension of more than 30 dyn / cm.

3. A coating composition according to claim 1 or 2, wherein the high-boiling, low-polarity organic solvent is blended in the coating composition in an amount of 5 to 50 parts by mass per 100 parts by mass of the fluororesin.

4. The coating composition according to any one of claims 1 to 3, wherein the high-boiling, low-polarity organic solvent is at least one selected from the group consisting of aliphatic hydrocarbons having 9 to 20 carbon atoms, aromatic hydrocarbons having 9 to 20 carbon atoms, diethylene glycol monobutyl ether, propylene glycol methyl ether, coal tar naphtha, 3-methoxy-3-methylbutyl acetate, and triethylene glycol monobutyl ether.

5. A coating film comprising a fluororesin and an engineering plastic (excluding the fluororesin), wherein the fluorine concentration measured on the film surface is 65 mass % or more.

6. A long medical device having on its surface a coating film obtained by applying the coating composition according to any one of claims 1 to 4 or the coating film according to claim 5.

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