Cable surface treatment method and cable

Abstract

The present invention provides a surface treatment method for cables equipped with a sheath primarily composed of polyvinyl chloride resin, which can repair deterioration of the sheath caused by chemical disinfection or UV-C light sterilization, and improve resistance to these treatments, as well as a cable surface-treated by this method. [Solution] A surface treatment method for a cable 1 having a sheath 10 mainly composed of a vinyl chloride resin is provided, wherein a liquid silicone rubber composition containing a UV-C light shielding filler 112 is applied to the surface of the sheath 10 and cured to form a coating layer 11 on the surface of the sheath 10.

Description

Technical Field

[0001] The present invention relates to a method for surface treatment of a cable and a cable.

Background Art

[0002] Conventionally, cables used in medical devices such as ultrasonic probes and endoscopes widely use a sheath mainly composed of a vinyl chloride resin (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, the sheath of a cable used in a medical device is subjected to disinfection treatment with a chemical or sterilization treatment with UV-C light to prevent infectious diseases. However, in a cable provided with a sheath mainly composed of a vinyl chloride resin, when these disinfection treatments or sterilization treatments are performed on the sheath, the progress of deterioration such as discoloration (yellowing) and stickiness (bleed phenomenon) due to the appearance of a plasticizer becomes remarkable. Therefore, even if there is no problem with the function as a cable, the use may be restricted early due to hygienic problems or the like. Therefore, for a cable provided with a sheath mainly composed of a vinyl chloride resin, in order to repair the deterioration of the sheath or to suppress the deterioration of the sheath in advance (slow down the progress of deterioration), an improvement in resistance to disinfection treatment with a chemical or sterilization treatment with UV-C light is required. <000002​​The object of the present invention is to provide a cable surface treatment method that can repair deterioration of the sheath caused by chemical disinfection or UV-C light sterilization in a cable having a sheath mainly composed of polyvinyl chloride resin, and to improve resistance to these treatments, and to provide a cable surface-treated by this method. [Means for solving the problem]

[0006] The present invention aims to solve the above problems and provides a surface treatment method for a cable having a sheath mainly composed of a vinyl chloride resin, wherein a liquid silicone rubber composition containing a UV-C light shielding filler is applied to the surface of the sheath and cured to form a coating layer on the surface of the sheath.

[0007] Furthermore, the present invention aims to solve the above problems by providing a cable comprising a sheath mainly composed of a vinyl chloride resin and a covering layer that covers the sheath, the covering layer being made of a liquid silicone rubber composition containing a filler that shields against UV-C light. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a cable surface treatment method that can repair deterioration of the sheath caused by chemical disinfection or UV-C light sterilization in a cable having a sheath mainly composed of polyvinyl chloride resin, and to improve resistance to these treatments, as well as a cable surface-treated by this method. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a cross-sectional view of the vicinity of the surface layer of a cable according to an embodiment of the present invention. [Figure 2] Figure 2 is a schematic external view showing the configuration of a medical ultrasound probe cable using the cable according to an embodiment of the present invention. [Figure 3]Figure 3(a) is a radial cross-sectional view of the ultrasonic probe cable. Figure 3(b) is a radial cross-sectional view of the ultrasonic probe cable cut along the cutting line AA shown in Figure 2. [Figure 4] Figure 4(a) is a radial cross-sectional view of the cable before surface treatment. Figure 4(b) is a radial cross-sectional view of an ultrasonic probe cable with the cable before surface treatment. [Figure 5] Figure 5 is a photograph of the external appearance of a cable in which a protective layer has been formed by applying a surface treatment to a portion of the deteriorated sheath. [Modes for carrying out the invention]

[0010] A surface treatment method for a cable according to an embodiment of the present invention is a surface treatment method for a cable having a sheath mainly composed of a vinyl chloride resin, wherein a coating layer is formed on the surface of the sheath by applying a liquid silicone rubber composition to the surface of the sheath and curing it.

[0011] The following describes the configuration of a cable surface-treated by the cable surface treatment method according to an embodiment of the present invention, as well as specific examples of the cable surface treatment method.

[0012] (Cable configuration) Figure 1 is an enlarged cross-sectional view of the vicinity of the surface layer of cable 1 according to an embodiment of the present invention. Figure 1 shows a cross-section of the sheath 10 of cable 1, which is mainly composed of polyvinyl chloride resin, and a covering layer 11 which is mainly composed of silicone rubber and covers the sheath 10.

[0013] Sheath 10 is a layer made of a vinyl chloride resin, or a layer with a vinyl chloride resin as the base material and containing additives such as pigments, stabilizers, auxiliary plasticizers, lubricants, and antioxidants. Here, vinyl chloride resin refers to a vinyl chloride homopolymer, or a copolymer of vinyl chloride and monomers copolymerizable with vinyl chloride, mainly composed of vinyl chloride.

[0014] The coating layer 11 is a layer with silicone rubber as the base material 111 and containing UV-C light-shielding fillers 112 such as titanium dioxide (TiO2) fine particles and zinc oxide (ZnO) fine particles. In addition to the powder 113 described later and the fillers that absorb and / or reflect visible light, the coating layer 11 may also contain nanosilica or the like. The coating layer 11 is made from a liquid silicone rubber composition containing the fillers 112.

[0015] For example, an addition reaction type or a condensation reaction type can be used as the liquid silicone rubber composition (silicone rubber coating agent) used to form the coating layer 11.

[0016] In particular, since the vinyl chloride resin, which is the main component of the sheath 10, generally has a low heat resistance temperature, it is preferable to use a condensation reaction type liquid silicone rubber composition that can be cured without applying heat to form the coating layer 11. As a condensation reaction type liquid silicone rubber composition, for example, KE-45W manufactured by Shin-Etsu Chemical can be used.

[0017] Furthermore, even if an addition-reaction type liquid silicone rubber composition that hardens when heat is applied is used, if a type with a low curing temperature is used, or if a heat-resistant vinyl chloride resin is used for the vinyl chloride resin that is the main component of the sheath 10, the addition-reaction type liquid silicone rubber composition may be used to form the coating layer 11.

[0018] The silicone rubber, which is the base material 111 of the coating layer 11, has higher resistance to UV-A and UV-B light compared to the vinyl chloride resin, which is the main component of the sheath 10. Furthermore, since the coating layer 11 contains a filler 112 that shields against UV-C light, it also has excellent resistance to UV-C light. In addition, silicone rubber has higher chemical resistance compared to vinyl chloride resin. Therefore, by covering the surface of the sheath 10 with the coating layer 11, the resistance of the cable 1 to chemical disinfection treatment and UV-C light sterilization treatment can be improved, and the occurrence of stickiness (bleeding phenomenon) and yellowing can be suppressed.

[0019] Even if the sheath 10 has already become sticky due to disinfection treatment with chemicals or sterilization treatment with UV-C light, the stickiness on the surface of the cable 1 can be eliminated by covering the surface of the sheath 10 with the coating layer 11.

[0020] Here, UV-A light is ultraviolet light in the wavelength range of 400 to 315 nm, UV-B light is ultraviolet light in the wavelength range of 315 to 280 nm, and UV-C light is ultraviolet light in the wavelength range of 200 to 280 nm.

[0021] The TiO2 fine particles that can be used as the filler 112 can shield UV-C light. By shielding UV-C light with the TiO2 fine particles, the deterioration of the silicone rubber, which is the base material 111 of the coating layer 11, due to UV-C light can be suppressed. The TiO2 constituting the TiO2 fine particles may be any of the anatase type, rutile type, or brookite type, or may be a mixture of two or more. Further, niobium oxide may be added to TiO2 to impart stability.

[0022] When the coating layer 11 contains TiO2 fine particles as the filler 112, the Ti concentration in the coating layer 11 is preferably 1.0 mass% or more and 4.4 mass% or less. By including TiO2 fine particles having a concentration such that the Ti concentration is 1.0 mass% or more in the coating layer 11, the occurrence of cracks in the coating layer 11 when the cable 1 is bent can be suppressed.

[0023] On the other hand, if the coating layer 11 contains TiO2 fine particles at a concentration exceeding 4.4% by mass, the surface roughness of the coating layer 11 increases. Increased surface roughness makes it easier for dirt and bacteria to adhere, and makes it difficult to remove the dirt and bacteria that have adhered. Furthermore, if the coating layer 11 contains powder 113 such as silicone resin fine particles described later, if it contains TiO2 fine particles at a concentration exceeding 4.4% by mass, the adhesion between the silicone rubber base material 111 and the powder 113 decreases, making it easier for the powder 113 to fall off the surface of the base material 111, and reducing the surface sliding properties of the coating layer 11. For this reason, it is preferable that the Ti concentration in the coating layer 11 be 4.4% by mass or less.

[0024] Note that all Ti in the coating layer 11 is contained in the filler 112. The Ti concentration in the coating layer 11 is determined as the average value over a measurement area of ​​125 μm x 95 μm using an energy-dispersive X-ray analyzer (EDS) mounted on a scanning electron microscope (SEM).

[0025] Furthermore, it is preferable that the coating layer 11 contains a filler that absorbs and / or reflects visible light. In this case, by covering the surface of the sheath 10 with the coating layer 11, the yellowing of the sheath 10 caused by UV-C light irradiation can be concealed, and the deterioration of its appearance can be repaired. Examples of such fillers include inorganic pigments and carbon black.

[0026] TiO2 nanoparticles and ZnO nanoparticles that can be used as filler 112 have the property of absorbing and / or reflecting visible light. That is, when TiO2 nanoparticles or ZnO nanoparticles are used as filler 112, the coating layer 11 can be said to contain both a filler that shields ultraviolet light and a filler that absorbs and / or reflects visible light. In addition, the coating layer 11 may also contain a filler that absorbs and / or reflects visible light separately from the filler 112.

[0027] Furthermore, it is preferable that the coating layer 11 contains powder 113 to give its surface an uneven surface. When the surface of the coating layer 11 has an uneven surface, the contact area when the coating layer 11 comes into contact with the object is reduced compared to when the surface is flat, and the surface sliding properties of the cable 1 are improved. Generally, silicone rubber has a higher coefficient of static friction on its surface compared to vinyl chloride resin (for example, the coefficient of static friction of polyvinyl chloride is about 0.2) and has lower surface sliding properties. However, by including powder 113 in the coating layer 11, surface sliding properties equivalent to or better than those of a layer made of vinyl chloride resin can be obtained (for example, the coefficient of static friction is about 0.05 to 0.2).

[0028] Powder 113 includes, for example, at least one of silicone resin microparticles, silicone rubber microparticles, and silica microparticles. Silicone resin, which has fewer reactive groups (e.g., methyl groups) than silicone rubber, has higher hardness than silicone rubber, and silica, which has no reactive groups, has even higher hardness. In terms of density, silica has the highest density, followed by silicone resin, and then silicone rubber has the lowest density.

[0029] To suppress deformation of surface irregularities when the coating layer 11 comes into contact with an object, it is preferable that the powder 113 has high hardness. This is because, when pressure is applied to the surface of the coating layer 11 by the object, the higher the hardness of the powder 113, the more effectively deformation of surface irregularities can be suppressed. This suppresses the increase in the contact area between the coating layer 11 and the object, and maintains surface sliding properties. For this reason, from the viewpoint of suppressing deformation of surface irregularities when the coating layer 11 comes into contact with an object, it is most preferable to use silica fine particles as the powder 113, and the next most preferable to use silicone resin fine particles.

[0030] On the other hand, as mentioned above, silica has a high density, so silica fine particles tend to settle in the liquid silicone rubber composition that forms the base material during the manufacturing process of the coating layer 11, making it difficult to disperse them in the liquid silicone rubber composition (i.e., disperse them in the coating layer 11) compared to silicone resin fine particles or silicone rubber fine particles. Therefore, from the viewpoint of improving the uniformity of dispersion in the liquid silicone rubber composition (i.e., dispersion in the coating layer 11), it is most preferable to use silicone rubber fine particles as the powder 113, and the next most preferable is to use silicone resin fine particles.

[0031] Therefore, in order to maintain the surface sliding properties when the coating layer 11 comes into contact with an object and to ensure the uniformity of the dispersion of the powder 113 in the coating layer 11, it is preferable to use silicone resin fine particles as the powder 113.

[0032] Furthermore, the interatomic bond energies in the molecular structures of silicone resin and silica are higher than those in the molecular structure of silicone rubber. For this reason, silicone resin and silica have higher resistance to UV-C light than silicone rubber.

[0033] For example, the CH bond, which is abundant in silicone rubber, has a bond energy (approximately 4.27 eV) that is lower than the energy of UV-C light (approximately 6.2 eV), so the bond breaks when irradiated with UV-C light. However, the Si-O bond, which is abundant in silicone resin, has a bond energy (approximately 6.52 eV) that is higher than the energy of UV-C light, so the bond does not break when irradiated with UV-C light. For this reason, from the viewpoint of resistance to UV-C light, it is preferable to use silicone resin fine particles or silica fine particles as powder 113.

[0034] The average particle size of powder 113 is, for example, 1 μm or more and 10 μm or less. The concentration (mass%) of powder 113 in the coating layer 11 is, for example, 10% by mass or more and 60% by mass or less. The concentration (mass%) of powder 113 is calculated assuming that the liquid silicone rubber composition hardens with almost no mass loss, and represents the ratio of the mass of powder 113 to the mass of the hardened coating layer 11 (the sum of the mass of the rubber component and the mass of powder 113). Here, "average particle size" in this specification refers to the particle size measured by laser diffraction scattering.

[0035] In order to obtain good surface sliding properties and wipe resistance (properties that suppress the reduction of surface sliding properties caused by wiping with a nonwoven fabric containing disinfectant alcohol) on the surface of the cable 1 by the coating layer 11, it is preferable that the thickness of the coating layer 11 is 3 μm or more. There is no particular upper limit to the thickness of the coating layer 11, but from the viewpoint of productivity, high flexibility and high bendability, it is preferable that it be 100 μm or less.

[0036] Figure 2 is a schematic external view showing the configuration of a medical ultrasonic probe cable 2 using cable 1 according to an embodiment of the present invention. The ultrasonic probe cable 2 is an example of a device, etc., in which cable 1 according to an embodiment of the present invention is used.

[0037] In the ultrasonic probe cable 2, as shown in Figure 2, an ultrasonic probe 22 is attached to one end of the cable 1 via a boot 21 that protects this end. On the other hand, a connector 23 that connects to the main body of the ultrasonic imaging device is attached to the other end of the cable 1 via a boot 21 that protects this other end.

[0038] Figure 3(a) is a radial cross-sectional view of the cable 1 of the ultrasonic probe cable 2. Inside the cable 1, multiple wires 12, such as coaxial cables, are housed, and a shield 13, such as a braided shield, is provided to cover these multiple wires 12. A sheath 10 is provided to cover the shield 13. Furthermore, a covering layer 11 is formed to cover the periphery of the sheath 10. Note that the filler 112 and powder 113 in the covering layer 11 are not shown in the illustration.

[0039] Figure 3(b) is a radial cross-sectional view of the ultrasonic probe cable 2 cut along the cutting line AA shown in Figure 2. The boot 21 is attached to the covering layer 11 via an adhesive layer 24, as shown in Figure 3(b), so as to cover the covering layer 11. The boot 21 is made of, for example, polyvinyl chloride, silicone rubber, chloroprene rubber, etc. The adhesive layer 24 is made of, for example, a silicone-based adhesive or an epoxy-based adhesive.

[0040] Next, an example of a surface treatment method for cable 1 will be described. First, prepare cable 1a, which is cable 1 before surface treatment, that is, before the coating layer 11 is applied, with the sheath 10 as the outermost layer.

[0041] Figure 4(a) is a radial cross-sectional view of cable 1a. This cable 1a may be in an unused state where the sheath 10 is not sticky, yellowed, or otherwise deteriorated, or it may be in a state where the sheath 10 has deteriorated due to disinfection with chemicals or sterilization with UV-C light. The sheath 10 is formed, for example, by extrusion molding using an extruder. The sheath 10 may also have a multilayer structure, in which case at least the outermost layer should be a vinyl chloride resin layer mainly composed of vinyl chloride resin.

[0042] Next, a coating layer 11 is formed on the surface of the sheath 10 by applying a coating made of a liquid silicone rubber composition using methods such as dipping, spray coating, or roll coating. For example, in the dipping method, the cable 1a, which has been formed up to the sheath 10, is pulled up through the liquid coating and suspended, and the coating is dried at room temperature for a predetermined time (e.g., 24 hours) to form a coating layer 11 on the surface of the sheath 10. This dipping method is superior to the spray coating method and roll coating method in terms of the uniformity of the film thickness of the formed coating layer 11.

[0043] Furthermore, the dipping method allows for more precise control of the distribution of fine particles such as filler 112 and powder 113 in the coating layer 11 by adjusting the cable 1's pulling speed, thereby enhancing the effects of filler 112 and powder 113, such as resistance to UV-C light and surface sliding properties. This point will be explained below.

[0044] In the dipping method, paint adheres to the surface of the sheath 10 when the cable 1a is lifted from the liquid surface of the paint. When this paint adheres to the surface of the sheath 10, fine particles may move and self-align within the paint film. This self-alignment allows the fine particles to be densely distributed on the surface of the paint film. Furthermore, the slower the cable lifting speed, the more time is available for the fine particles to self-align, and the more stably the dense distribution of fine particles can be reproduced. Specifically, from the viewpoint of densely distributing fine particles, it is preferable to lift the cable 1 in the dipping method at a speed of 10 m / min or less, and more preferably at 5 m / min or less.

[0045] The liquid coating used in the dipping method is a liquid silicone rubber composition containing filler 112, powder 113, etc., and contains an organic solvent. By adjusting the content of filler 112 and powder 113 in this liquid coating, the content of filler 112 and powder 113 in the coating layer 11 can be controlled. As the organic solvent, for example, aromatic hydrocarbon solvents such as toluene and xylene, or aliphatic hydrocarbon solvents such as n-hexane, n-heptane, n-octane, isooctane, nonane, decane, undecane, and dodecane can be used alone or in combination of two or more. In addition, for example, alcohols such as ethanol and isopropyl alcohol, or acetone may be used as the organic solvent.

[0046] Furthermore, when applying the above surface treatment to cable 1a, the surface of the sheath 10 may be roughened beforehand by methods such as dry ice blasting or sandpapering before applying the surface treatment. The anchoring effect due to the roughening can improve the adhesion strength between the sheath 10 and the covering layer 11. Also, when repairing cable 1a, the discolored parts of the sheath 10 are removed by roughening, reducing the degree of yellowing, making it easier for the covering layer 11 to cover and conceal the yellowing of the sheath 10.

[0047] Figure 4(b) is a radial cross-sectional view of an ultrasonic probe cable in which a boot 21, an ultrasonic probe 22, and a connector 23 are attached to a cable 1a that has not undergone the surface treatment described above. The cutting positions of the cross-section in Figure 4(b) correspond to the cutting positions of the cross-section in Figure 3(b). In the ultrasonic probe cable shown in Figure 4(b), the boot 21 is directly attached to the sheath 10 via an adhesive layer 24 so as to cover the sheath 10. The cable 1a of this ultrasonic probe cable may also be subjected to the surface treatment described above.

[0048] When applying the above surface treatment to cable 1a of the ultrasonic probe cable shown in Figure 4(b), the treatment can be carried out without removing the boot 21, ultrasonic probe 22, and connector 23, by protecting them with a mask or the like. In this case, the cost associated with the surface treatment can be reduced compared to when the parts attached to cable 1a are removed before performing the surface treatment. This is also true when applying the above surface treatment to cable 1a with various other parts attached.

[0049] Figure 5 is a photograph of the external appearance of cable 1a in which a coating layer 11 has been formed by surface treatment on a portion of the deteriorated sheath 10. Approximately the left half of cable 1a shown in Figure 5 is the portion that has not been surface treated, and approximately the right half is the portion that has been surface treated to form the coating layer 11 (corresponding to cable 1). In forming the coating layer 11, the surface of the sheath 10 of cable 1a is wiped clean with an organic solvent such as ethanol, and then a liquid silicone rubber composition is applied and cured.

[0050] In the cable 1a shown in Figure 5, yellowing has occurred on the surface of the sheath 10, which is made of polyvinyl chloride resin (PVC), due to deterioration. On the left side of the cable 1a, a yellowed portion 100 extending linearly in the longitudinal direction of the cable 1a can be seen. On the other hand, in the surface-treated portion on the right side, the yellowed portion 100 is covered by the coating layer 11 and is not visible. Figure 5 shows that by forming a coating layer 11 on the surface of the deteriorated and yellowed sheath 10, the yellowing can be concealed and the deterioration in appearance can be repaired.

[0051] (Effects of the embodiment) According to this embodiment of the present invention, by covering the sheath 10 of a cable 1, which is mainly composed of a vinyl chloride resin, with a covering layer 11, it is possible to repair deterioration of the sheath 10 caused by chemical disinfection treatment or UV-C light sterilization treatment, and to improve the resistance of the cable 1 to chemical disinfection treatment or UV-C light sterilization treatment.

[0052] The cable surface treatment method according to the embodiment of the present invention can be suitably used for cables used in medical devices, such as the cable 1 used in the ultrasonic probe cable 2 described above, which have a sheath mainly composed of a polyvinyl chloride resin and are subjected to disinfection with chemicals or sterilization with UV-C light. However, it is not limited to this, and can be suitably used for all cables that have a sheath mainly composed of a polyvinyl chloride resin and are subjected to disinfection with chemicals or sterilization with UV-C light during use or maintenance.

[0053] (Summary of the embodiments) Next, the technical concept understood from the embodiments described above will be described using the reference numerals and other symbols from the embodiments. However, the reference numerals and other symbols in the following description are not limited to the components in the claims that are specifically shown in the embodiments.

[0054] [1] A surface treatment method for a cable (1) having a sheath (10) mainly composed of a vinyl chloride resin, wherein a liquid silicone rubber composition containing a UV-C light shielding filler (112) is applied to the surface of the sheath (10) and cured to form a coating layer (11) on the surface of the sheath (10).

[0055] [2] The surface treatment method for the cable (1) according to [1] above, wherein the coating layer (11) includes a filler that absorbs and / or reflects visible light.

[0056] [3] The surface treatment method for the cable (1) according to [1] or [2] above, wherein the coating layer (11) includes a powder (113) for giving the surface an uneven texture.

[0057] [4] The liquid silicone rubber composition is of the condensation reaction type, a surface treatment method for the cable (1) according to [1] or [2] above.

[0058] [5] A cable (1) comprising a sheath (10) mainly composed of a vinyl chloride resin, and a covering layer (11) which covers the sheath (10) and is made of a liquid silicone rubber composition containing a filler that shields against UV-C light.

[0059] [6] The cable (1) according to [5] above, wherein the covering layer (11) includes a filler that absorbs and / or reflects visible light.

[0060] [7] The cable (1) according to [5] or [6] above, wherein the covering layer (11) includes a powder (113) for giving the surface an uneven surface.

[0061] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention. Furthermore, the embodiments described above do not limit the invention as claimed. It should also be noted that not all combinations of features described in the embodiments are necessarily essential for solving the problem of the invention. [Explanation of symbols]

[0062] 1 Cable 10 sheaths 11 Covering layer 111 Base material 112 Filler 113 Powder

Claims

1. A surface treatment method for a cable having a sheath mainly composed of polyvinyl chloride resin, A coating layer is formed on the surface of the sheath by applying a liquid silicone rubber composition containing a filler that blocks UV-C light to the surface of the sheath and curing it. A method for treating the surface of a cable.

2. The coating layer includes a filler that absorbs and / or reflects visible light. The method for surface treatment of a cable according to claim 1.

3. The coating layer includes a powder for giving its surface an uneven surface. The method for surface treatment of a cable according to claim 1 or 2.

4. The aforementioned liquid silicone rubber composition is of the condensation reaction type. The method for surface treatment of a cable according to claim 1 or 2.

5. A sheath primarily composed of polyvinyl chloride resin, A coating layer comprising a liquid silicone rubber composition containing a filler that shields against UV-C light, which covers the sheath, A cable that is equipped with it.

6. The coating layer includes a filler that absorbs and / or reflects visible light. The cable according to claim 5.

7. The coating layer includes a powder for giving its surface an uneven surface. The cable according to claim 5 or 6.

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