Patent Application
20080078946
A method for manufacturing a wire that relates to an embodiment of the present invention is chiefly constituted from a primer application process, a colored fluororesin coating process and a colored fluororesin baking process. Moreover, the raw materials that are necessary in this method for manufacturing a wire are chiefly a superelastic alloy wire, primer, fluororesin and a coloring substance.
Below, after the necessary raw materials for implementing the present manufacturing method are mentioned, each process in the present manufacturing method will be described in detail.
(1) Superelastic Alloy Wire
For the superelastic alloy wire that is utilized in an embodiment of the present invention, either a straight shape or a fine-pointed taper shape is preferred. Examples of the superelastic alloy that can be named include Ni—Ti (Ni: 49-51 atom %, including a third element added to Ni—Ti), Cu—Al—Zn (Al: 3-8 atom %; Zn: 15-28 atom %), Fe—Mn—Si (Mn: 30 atom %, Si: 5 atom %), Cu—Al—Ni (Ni: 3-5 atom %, Al: 28-29 atom %), Ni—Al (Al: 36-38 atom %), Mn—Cu (Cu: 5-35 atom %), Au—Cd (Cd: 46-50 atom %) and the like. Furthermore, this superelastic alloy is also known as a shape-memory alloy. In the present invention, the Ni—Ti alloy is preferred. It is preferable for the size of the superelastic alloy wire to be selected by considering the inner diameter of the catheter with which it is to be used and a flexibility that is suitable for this use. In concrete terms, it is desirable to use a superelastic alloy wire with a diameter on the order of approx. 0.3-1 mm.
Furthermore, as the superelastic alloy wire in the present embodiment, it is also desirable to use a superelastic alloy wire that is coated with a synthetic resin (referred to below as a synthetic resin-coated superelastic alloy wire). Further, examples of the synthetic resin that can be named include common synthetic resins such as polyamide resin such as nylon, poly(vinyl chloride) resin, polypropylene resin, epoxy resin, poly(phenylene sulfide) resin, polyether sulfone resin, polyether ketone resin, polysulfone resin, polyamideimide resin, polyether amide resin, polyimide resin, silicone rubber, polyurethane resin and blends of the foregoing.
(2) Primer
The primer in the present embodiment is the solution of a resin with superior adhesive properties with respect to the superelastic alloy wire or a precursor of such a resin containing a fluororesin. Examples of resins that have superior adhesive properties with respect to the superelastic alloy wire include acrylic resin, epoxy resin as well as blends of the foregoing. Examples of the fluororesin that can be named include poly(tetrafluoroethylene) (PTFE), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), poly(chlorotrifluoroethylene) (PCTFE), poly(vinylidene fluoride) (PVDF), poly(vinyl fluoride) (PVF) as well as tetrafluoroethylene-ethylene copolymer (PETFE) or blends of the foregoing.
(3) Fluororesin
The fluororesin is preferably at least one fluororesin selected from the group consisting of poly(tetrafluoroethylene) (PTFE), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), poly(chlorotrifluoroethylene) (PCTFE), poly(vinylidene fluoride) (PVDF), poly(vinyl fluoride) (PVF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) or tetrafluoroethylene-ethylene copolymer (PETFE). Fluororesin is stable and inert, since it must be safe even when it comes into contact with blood when introduced into the body.
Furthermore, in the method for manufacturing the medical wire of the present embodiment, a dispersion or powder body form of the fluororesin can also be used.
(4) Pigment
For the pigment, it is preferable to select at least one pigment selected from the group consisting of inorganic white pigments such as zinc oxide (zinc white), lead white (silver white), lithopone (pigment mixture of zinc oxide and zinc sulfide), titanium dioxide (titanium white), ceramic white and the like, inorganic extender pigments such as precipitated barium sulfate and barite powder, inorganic red pigments such as red lead, Bengal red (red iron oxide), cadmium red, vermillion and the like, inorganic orange pigments such as cadmium orange, chrome vermillion and the like, inorganic yellow pigments such as yellow lead (chrome yellow), yellow zinc (zinc chromate, zinc yellow), cadmium yellow, yellow ochre, nickel titanium yellow, bismuth vanadium yellow and the like, inorganic brown pigments such as sienna earth, amber earth, Vandyke brown and the like, inorganic blue pigments such as ultramarine blue, iron blue (Prussian blue), cobalt blue, cerulean blue, manganese blue and the like, inorganic green pigments such as viridian, chrome oxide green, cobalt green and the like, inorganic purple pigments such as cobalt violet, manganese violet and the like, inorganic black pigments such as ivory black, peach black, lamp black, Mars black, compound oxide black, carbon black and the like, organic red pigments such as alizarin red, quinacridone red, naphthol red, monoazo red, polyazo red and the like, organic orange pigments such as benzimidazolone orange and the like, organic yellow pigments such as monoazo yellow, disazo yellow, polyazo yellow, benzimidazolone yellow, isoindolinone yellow and the like, organic brown pigments such as benzimidazolone brown, sepia and the like, organic blue pigments such as phthalocyanine blue and the like, organic green pigments such as phthalocyanine green and the like, organic purple pigments such as dioxazine violet, quinacridone violet and the like, and organic black pigments such as aniline black.
(1) Primer Application Process
In the primer application process, primer is applied to the outer circumference of the superelastic alloy wire or the synthetic resin coated superelastic alloy wire (this wire is referred to below as a primer-coated wire). Furthermore, when primer is applied to the superelastic alloy wire or the synthetic resin coated superelastic alloy wire, by regulating the viscosity of the primer liquid, it is possible to control the primer thickness when the superelastic alloy wire is withdrawn from the primer liquid at a constant rate of speed after the superelastic alloy wire is immersed. Further, the thickness of primer in this case is preferably in the range of 1-10 μm. More preferable is for the thickness to be in the range of 2-5 μm. Moreover, it is acceptable for inorganic powders such as metal, ceramic or the like or fluororesin powder to be added to the primer liquid. If this is done, it is possible as mentioned below to form microscopic protuberances in the surface of the fluororesin layer of the fluororesin-coated wire, and to further reduce the frictional resistance with the inner wall of the catheter. Furthermore, it is acceptable to use a pigment-containing primer that is a primer liquid that contains a pigment. With pigment being contained in the primer liquid, it will not be necessary for the fluororesin mentioned below to contain a pigment. In addition, if a pigment-containing primer and a pigment-containing fluororesin are used in the primer liquid application process and the fluororesin application process, the thickness of the pigment-containing layer can become thicker, and it can conceal the backing with a vivid color being easily brought out.
(2) Colored Fluororesin Application Method
In the colored fluororesin application method, a pigment-containing fluororesin dispersion, a fluororesin enamel liquid that contains a pigment, a pigment-containing fluororesin powder body or the like is applied to a primer-coated wire. Furthermore, if a pigment-containing fluororesin dispersion or a fluororesin enamel liquid that contains a pigment is applied to the primer-coated wire, by regulating the viscosity of the pigment-containing fluororesin dispersion or a fluororesin enamel liquid that contains a pigment, it is possible to control the thickness of the pigment-containing fluororesin if the primer-coated wire is withdrawn from the pigment-containing fluororesin dispersion or a fluororesin enamel liquid that contains a pigment at a constant rate of speed after the primer-coated wire has been immersed. Thereafter, the pigment-containing fluororesin dispersion or a fluororesin enamel liquid that contains a pigment on the primer-coated wire is dried, and a pigment-containing fluororesin layer is formed on the primer-coated wire (this wire is referred to below as a pigment-containing fluororesin-coated wire). Additionally, when a pigment-containing primer has been used in the aforementioned primer application process, it is not necessary for the fluororesin to contain a pigment. In addition, if a pigment-containing primer and a pigment-containing fluororesin are used in the primer liquid application process and the fluororesin application process, the thickness of the pigment-containing layer can become thicker, and it can conceal the backing with a vivid color being easily brought out. In addition, if a pigment-containing powder body is applied to the primer-coated wire, the thickness of the fluororesin can be controlled if a suitable particle size is selected for the fluororesin powder body. Furthermore, this thickness of the pigment-containing fluororesin is preferably in the range 1-50 μm, and is preferably thinner than the thickness of the synthetic resin layer. If the thickness of the pigment-containing fluororesin layer exceeds 50 μm, the rigidity of the fluororesin will exert an effect on the flexibility of the wire, and moreover if the thickness is ≦1 μm, sufficient sliding characteristics and durability will not be obtained. Additionally, the layer with a thickness of 5-30 μm is more preferred. In addition, the layer with a thickness of 5-20 μm is further preferred. Moreover, it is acceptable for inorganic powders such as metal, ceramic or the like or fluororesin powder to be added to the pigment-containing fluororesin dispersion or fluororesin enamel liquid that contains a pigment. If this is done, it is possible to form microscopic protuberances in the surface of the fluororesin layer, and to further reduce the frictional resistance with the inner wall of the catheter. Additionally, in the present invention, it is also possible to use dyes without exceeding the scope of the present invention.
(3) Colored Fluororesin Baking Process
In the colored fluororesin baking process, the pigment-containing fluororesin-coated wire is passed into a tunnel furnace that comprises a quartz heater, and the pigment-containing fluororesin that constitutes the outermost layer of the pigment-containing fluororesin-coated wired is heated and baked. Furthermore, in this case, it is preferred to use the quartz heater that can irradiate infrared radiation with a peak wavelength of 1.5-5.6 μm (middle infrared region). In addition, the use of the quartz heater that can irradiate infrared radiation with a peak wavelength of 0.9-1.6 μm (near infrared region) is further preferred.
Furthermore, while it is preferable for the abovementioned primer application process, colored fluororesin application process and colored fluororesin baking process to be carried out continuously, it is acceptable for them to be carried out in batch mode.
Further, while a guide wire was manufactured using the abovementioned method for manufacturing that relates to the present invention, this manufacturing method that relates to the present invention can also be used for manufacturing a catheter or other medical devices. If this is done, it is possible to obtain the same effect.
The present invention is further explained below in concrete terms using various Examples.
After a Ni—Ti (Ni: 49-51 atom %) superelastic alloy wire with a diameter of 0.35 mm was immersed in a fluororesin primer liquid (solid fraction concentration: 35 wt %) (DuPont Co. tradename: 855-300) at 23° C. with the viscosity regulated at 110 cP (centipoise), it was withdrawn at a constant rate of speed and then dried at 150° C. This resulted in a fluororesin layer with a thickness of approx. 1 μm being formed on the Ni—Ti superelastic alloy wire (this wire is referred to below as a primer-coated wire). Next, after the primer-coated wire was immersed in a PTFE dispersion (DuPont Co. tradename: 855-510) that contains zinc yellow pigment (solid fraction concentration: 50 wt %), it was withdrawn at a constant rate of speed and was then allowed to dry naturally. This resulted in a yellow-colored PTFE resin layer with a thickness of approx. 5 μm being formed on the primer-coated wire (this wire is referred to below as a yellow-colored PTFE resin-coated wire). To continue, the yellow-colored PTFE resin-coated wire was passed into a tunnel furnace that comprises a quartz heater (peak wavelength 3 μm) at a temperature of 350° C. as measured by thermocouple for a period of 10 seconds to bake the yellow-colored PTFE resin (this wire is referred to below as a baked yellow-colored PTFE resin-coated wire). When the color of the baked yellow-colored PTFE resin-coated wire obtained thereby was checked, no discoloration was observed. Moreover, when the yellow-colored PTFE resin layer and the fluororesin primer layer were removed from the thus obtained baked yellow-colored PTFE resin-coated wire and the outer surface of the Ni—Ti superelastic alloy wire was observed, no discoloration of the Ni—Ti superelastic alloy wire was observed. In addition, after the baked yellow-colored PTFE resin-coated wire was wrapped around a pipe of diameter 10 mm and then released, it returned to its original shape without taking on a bending habit. From this fact it was concluded that the superelasticity of the Ni—Ti superelastic alloy wire was maintained.
A baked yellow-colored PFA resin-coated wire was manufactured under the same conditions as were used for the first example, except that the PTFE dispersion of the first example was replaced with a PFA dispersion. When the color of the baked yellow-colored PFA resin-coated wire obtained thereby was checked, no discoloration was observed. Additionally, when the yellow-colored PFA resin layer and the fluororesin primer layer were removed from the thus obtained baked yellow-colored PFA resin-coated wire and the outer surface of the Ni—Ti superelastic alloy wire was observed, no discoloration of the Ni—Ti superelastic alloy wire was observed. Moreover, after baked PFA resin-coated wire was wrapped around a pipe of diameter 10 mm and then released, it returned to its original shape without taking on a bending habit. From this fact it was concluded that the superelasticity of the Ni—Ti superelastic alloy wire was maintained.
A Ni—Ti (Ni: 49-51 atom %) superelastic alloy wire with a diameter of 0.35 mm, after being immersed in a fluororesin primer liquid (solid fraction concentration: 35 wt %) (DuPont Co. tradename: 855-300) at 23° C. with the viscosity regulated at 110 cP (centipoise), was withdrawn at a constant rate of speed (this wire is referred to below as a primer-coated wire), and then without the fluororesin primer liquid on the primer-coated wire being completely dried, a powder body of zinc yellow pigment-containing PTFE powder (Asahi Glass Co. tradename: L150J (mean particle size: approx. 9 μm)) was applied the primer-coated wire, which was then allowed to dry naturally (this wire is referred to below as a yellow-colored PTFE resin-coated wire). To continue, the yellow-colored PTFE resin-coated wire was passed into a tunnel furnace that comprises a quartz heater (peak wavelength 1 μm) at a temperature of 350° C. as measured by thermocouple for a period of 10 seconds to bake the yellow-colored PTFE resin (this wire is referred to below as a baked yellow-colored PTFE resin-coated wire). When the color of the baked yellow-colored PTFE resin-coated wire obtained thereby was checked, no discoloration was observed. Moreover, when the yellow-colored PTFE resin layer and the fluororesin primer layer were removed from the thus obtained baked yellow-colored PTFE resin-covered wire and the outer surface of the Ni—Ti superelastic alloy wire was observed, no discoloration of the Ni—Ti superelastic alloy wire was observed. In addition, after the baked yellow-colored PTFE resin-coated wire was wrapped around a pipe of diameter 10 mm and then released, it returned to its original shape without taking on a bending habit. From this fact it was concluded that the superelasticity of the Ni—Ti superelastic alloy wire was maintained.
A pigment-containing primer liquid was prepared by adding polyamidoimide varnish (Hitachi Chemical Co., Ltd., tradename: HPC-1000) and zinc yellow pigment to a PTFE dispersion (Asahi Glass Co. tradename: AD912) so that the polyamidoimide varnish can be 20 wt % and the zinc yellow pigment can be 30 wt of to the total weight. Then, a primer-coated wire was manufactured in the same manner of conditions as in the first example, except that the primer liquid used in the first example was replaced with the pigment-containing primer liquid. Next, except for the zinc yellow pigment-containing PTFE dispersion in the first example being replaced by a PTFE dispersion (Asahi Glass Co. tradename: AD912), the coating and baking of the PTFE resin was carried out under the same conditions used in the first example. When the color of the baked yellow-colored PTFE resin-coated wire obtained thereby was checked, no discoloration was observed. Moreover, when the PTFE resin layer and the yellow-colored fluororesin primer layer were removed from the thus obtained baked yellow-colored PTFE resin-coated wire and the outer surface of the Ni—Ti superelastic alloy wire was observed, no discoloration of the Ni—Ti superelastic alloy wire was observed. Additionally, after the baked yellow-colored PTFE resin-coated wire was wrapped around a pipe of diameter 10 mm and then released, it returned to its original shape without taking on a bending habit. From this fact it was concluded that the superelasticity of the Ni—Ti superelastic alloy wire was maintained.
With the exception of the PTFE dispersion in fourth example being replaced by a zinc yellow pigment-containing PTFE dispersion, the PTFE resin was coated and baked under the same manner of conditions as for the fourth example. When the color of the baked yellow-colored PTFE resin-coated wire obtained thereby was checked, no discoloration was observed. Moreover, when the yellow-colored PTFE resin layer and the yellow-colored fluororesin primer layer were removed from the thus obtained baked yellow-colored PTFE resin-coated wire and the outer surface of the Ni—Ti superelastic alloy wire was observed, no discoloration of the Ni—Ti superelastic alloy wire was observed. In addition, after the baked yellow-colored PTFE resin-coated wire was wrapped around a pipe of diameter 10 mm and then released, it returned to its original shape without taking on a bending habit. From this fact it was concluded that the superelasticity of the Ni—Ti superelastic alloy wire was maintained.
The tunnel furnace in the first example was replaced with a circulating hot air oven with an ambient air temperature of 390° C., and the yellow-colored PTFE resin-coated wire was baked for 30 minutes. When the color of the baked yellow-colored PTFE resin-coated wire obtained thereby was checked, a slight discoloration was observed. Moreover, when the yellow-colored PTFE resin layer and the fluororesin primer layer were removed from the thus obtained baked yellow-colored PTFE resin-coated wire and the outer surface of the Ni—Ti superelastic alloy wire was observed, the Ni—Ti superelastic alloy wire was observed to have undergone a color change to a gold color, which was interpreted as due to oxidation. In addition, after the baked yellow-colored PTFE resin-coated wire was wrapped around a pipe of diameter 10 mm and then released, it did not return to its original shape and had taken on a bending habit. From this fact it was concluded that the superelasticity of the Ni—Ti superelastic alloy wire was impaired.
The PTFE dispersion in the first example was replaced with an FEP dispersion, and further the tunnel furnace in the first example was replaced with a circulating hot air oven with an ambient air temperature of 350° C., and the yellow-colored FEP resin-coated wire was baked for 30 minutes. When the color of the baked yellow-colored FEP resin-coated wire obtained thereby was checked, a slight discoloration was observed. Additionally, when the yellow-colored FEP resin layer and the fluororesin primer layer were removed from the thus obtained baked yellow-colored FEP resin-coated wire and the outer surface of the Ni—Ti superelastic alloy wire was observed, the Ni—Ti superelastic alloy wire was observed to have undergone a color change to a gold color, which was interpreted as due to oxidation. Moreover, after the baked yellow-colored PTFE resin-coated wire was wrapped around a pipe of diameter 10 mm and then released, it had taken on a bending habit and did not return to its original shape. From this fact it was concluded that the superelasticity of the Ni—Ti superelastic alloy wire was impaired.
A Ni—Ti (Ni: 49-51 atom %) superelastic alloy wire with a diameter of 0.35 mm was passed into a tunnel furnace that comprises a quartz heater (peak wavelength 3 μm) at a temperature of 350° C. as measured by thermocouple for a period of 10 seconds. When the outer surface of the Ni—Ti superelastic alloy wire was observed after passing through the tunnel furnace, no discoloration was observed.
A Ni—Ti (Ni: 49-51 atom %) superelastic alloy wire with a diameter of 0.35 mm was allowed to stand in a circulating hot air oven with an ambient air temperature of 350° C. for a period of 30 minutes. When withdrawn from the oven, the Ni—Ti superelastic alloy wire was observed to have undergone a color change to a gold color, which was interpreted as due to oxidation.
The method for manufacturing a medical device that relates to the present invention has exceptional utility in that the elastic modulus of a superelastic alloy wire is maintained when the superelastic alloy wire is coated with a fluororesin. Moreover, the method for the manufacture a medical wire relating to the present invention possesses the characteristics that the superior properties of the fluororesin can be elicited without any fading of the color of the colored substance, and the use of fluororesin as the material for the outermost layer constitutes an extremely effective way to color a medical device.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-271227 | Oct 2006 | JP | national |
