JP2022122044A - Laminated structure body, cable and tube - Google Patents

Abstract

To provide a laminated structure body that is formed of a silicone rubber as a base material and has an excellent resistance to UV-C light, and a cable and tube having an insulation body composed of the laminated structure body.SOLUTION: There is provided a laminated structure body 1 that comprises: a first layer 10 as a base material; and a second layer 11 that is formed from a rubber composition containing a rubber component, first fine particles 112 for imparting unevenness to a surface, and second fine particles 113 for shielding UV-C light, and is laminated on the first layer 10, in which when Raman mapping analysis is performed on a first peak derived from a vibration of the second fine particles 113 contained in a Raman scattering spectrum obtained by a Raman scattering measurement of the second layer 11, the second layer has a region where an intensity of the first peak is higher in a region where the first fine particles 112 do not exist than in a region where the first fine particles 112 exist.SELECTED DRAWING: Figure 1

Description

The present invention relates to laminated structures, cables and tubes.

Conventionally, a cable for medical equipment is known which is made of silicone rubber containing fine particles and has a coating provided so as to cover a sheath (see Patent Document 1). Compared to polyvinyl chloride (PVC), which has been generally used as a conventional sheath material, silicone rubber has advantages such as almost no discoloration with the passage of time, but its surface lubricity is low. There is a tendency.

Since the coating of the cable described in Patent Literature 1 is made of silicone rubber containing fine particles, the surface thereof has irregularities derived from the fine particles. These unevennesses can reduce the contact area when the coating and other members come into contact with each other, and can improve the lubricity of the coating surface, that is, the lubricity of the cable.

Japanese Patent No. 6723489

In recent years, as a method of sterilizing cables for medical equipment, a method of sterilization by irradiation with UV-C light has attracted attention because it is simple, inexpensive, and can be sterilized reliably. In order to do so, the resistance of the cable to UV-C light becomes a problem. It has been confirmed that a cable having a sheath made of silicone rubber also deteriorates when repeatedly irradiated with UV-C light, and cracks occur in the sheath when the cable is subjected to stress such as bending.

An object of the present invention is to provide a laminated structure having silicone rubber as a base material, which is excellent in resistance to UV-C light, and a cable and tube provided with an insulator comprising the laminated structure. to do.

In order to solve the above problems, the present invention provides a first layer that serves as a base material, a rubber component, first fine particles for imparting unevenness to the surface, and a second layer for shielding UV-C light. a second layer formed from a rubber composition containing fine particles of 2 and laminated on the first layer, and the second layer included in the Raman scattering spectrum obtained by Raman scattering measurement of the second layer When Raman mapping analysis is performed on the first peak derived from the vibration of the fine particles in 2, the intensity of the first peak in the region where the first fine particles are not present is higher than the region where the first fine particles are present. To provide a laminated structure having a region in which is increased.

Moreover, in order to solve the above problems, the present invention provides a cable or tube having an insulator comprising the above laminated structure.

INDUSTRIAL APPLICABILITY According to the present invention, there are provided a laminated structure having silicone rubber as a base material and having excellent resistance to UV-C light, and a cable and tube provided with an insulator comprising the laminated structure. can do.

FIG. 1 is a vertical sectional view of a laminated structure according to a first embodiment of the invention. FIG. 2 is a plan view schematically showing the configuration of an ultrasonic probe cable according to the second embodiment of the invention. FIG. 3A is a radial cross-sectional view of the ultrasonic probe cable. FIG. 3(b) is a radial cross-sectional view of the ultrasonic probe cable cut along the cutting line AA shown in FIG. 4A to 4C are radial cross-sectional views of a medical tube according to a second embodiment of the present invention. FIG. 5(a) is a graph showing the results of the tensile test of sample A1. FIG.5(b) is a graph which shows the result of the tension test of sample A2. FIG. 6(a) is a graph showing the results of the tensile test of sample A3. FIG.6(b) is a graph which shows the result of the tension test of sample A4. FIG. 7(a) is a graph showing the relationship between the irradiation time of UV-C light and the stress at breakage of the substrate for samples A1 to A4. FIG. 7(b) is a graph showing the relationship between the irradiation time of UV-C light and the elongation at break of the substrate for samples A1 to A4. FIG. 8 is a graph showing a Raman scattering spectrum measured at a certain point of sample B1. FIG. 9(a) is a mapping image of sample B1 obtained by mapping analysis. FIG. 9(b) is a binarized analysis image obtained by binarizing the mapping image of FIG. 9(a). FIG. 10(a) is a mapping image of sample B2 obtained by mapping analysis. FIG. 10(b) is a binarized analysis image obtained by binarizing the mapping image of FIG. 10(a). FIG. 11(a) is a mapping image of sample B3 obtained by mapping analysis. FIG. 11(b) is a binarized analysis image obtained by binarizing the mapping image of FIG. 11(a). FIG. 12(a) is a mapping image of sample B4 obtained by mapping analysis. FIG. 12(b) is a binarized analysis image obtained by binarizing the mapping image of FIG. 12(a).

[First embodiment]
(Structure of laminated structure)
FIG. 1 is a vertical sectional view of a laminated structure 1 according to a first embodiment of the invention. The laminated structure 1 includes a first layer 10 having a silicone rubber as a base material, and a first layer 111 having a silicone rubber as a base material laminated on the first layer 10 for imparting unevenness to the surface. It comprises particulates 112 and a second layer 11 comprising second particulates 113 for blocking UV-C light by absorption and/or scattering.

The first fine particles 112 are made of a Si-containing material such as silicone resin or silica, which has higher resistance to UV-C light than silicone rubber. Also, the average particle size of the second fine particles 113 is preferably smaller than the average particle size of the first fine particles 112 . For example, the average particle size of the second fine particles 113 is preferably 1/2 or less, more preferably 1/5 or less of the average particle size of the first fine particles 112 . As a result, the second fine particles 113 are segregated around the first fine particles 112, and the second fine particles 113 are selectively arranged in regions in the in-plane direction of the second layer 11 where the first fine particles 112 do not exist. can be made Here, UV-C light is ultraviolet light in the wavelength range of 200-280 nm.

Silicone rubber, which is the base material of the first layer 10 and the second layer 11, is a type of silicone resin. Silicone rubber has higher resistance to ultraviolet rays (UV-A light and UV-B light) than polyvinyl chloride, which has been generally used as a material for cables and tubes used in medical applications.

In addition, silicone rubber is added with first fine particles 112, which are fine particles containing Si such as silicone resin fine particles and silica (silicon oxide) fine particles, to form unevenness on the surface, thereby suppressing surface stickiness (tack). Slipperiness (slidability) can be improved. Therefore, by laminating the second layer 11 made of silicone rubber to which the first fine particles 112 are added on the first layer 10 made of silicone rubber that does not contain the first fine particles 112 to cover the surface thereof, silicone It is possible to suppress the stickiness of the surface of the rubber and improve the slipperiness.

On the other hand, the silicone rubber that does not contain the first fine particles 112 seems to have performance as a substrate (for example, the function of protecting or containing other articles) compared to the silicone rubber that contains the first fine particles 112. requires a certain thickness. Therefore, when the laminated structure 1 is used as an insulator for a cable or tube, the first layer 10 is formed by extrusion or the like with excellent productivity, and the second layer is formed thereon by a method such as coating. 11 is preferably laminated.

The laminated structure 1 can take various forms depending on its use. For example, when it is used as an insulator for cables and tubes, it is molded into a tubular shape, and is used as a sheet for temperature-controlled greenhouses with high UV resistance, or as an UV shielding sheet (UV shielding curtain) for blocking UV leakage from sterilization rooms, etc. When used, it is formed into sheets.

(Configuration of second layer)
Since the second layer 11 contains the first fine particles 112, the surface thereof has an uneven shape. As a result, the contact area of the second layer 11 when it comes into contact with a contacting object is reduced and the slipperiness is enhanced, compared to the case where the surface is flat.

As the silicone rubber that is the base material 111 of the second layer 11, for example, an addition reaction type silicone rubber coating agent or a condensation reaction type silicone rubber coating agent can be used. In particular, it is preferable to use an addition reaction type silicone rubber coating agent from the viewpoint of adhesion to the first layer 10 having a base material of silicone rubber and abrasion resistance.

The second layer 11 preferably has a thickness of 3 μm or more so that the surface of the laminated structure 1 can have good lubricity and predetermined wiping resistance. Also, the second layer 11 may be laminated on both sides of the first layer 10 . Although the upper limit of the thickness of the second layer 11 is not particularly limited, it is preferably 100 μm or less from the viewpoint of productivity, high flexibility, and high bendability.

The first microparticles 112 are, for example, silicone resin microparticles, silica microparticles, or a mixture of these two. The first microparticles 112 preferably have a hardness higher than that of the base material 111 made of silicone rubber (for example, a Shore (durometer A) hardness of about 1.1 times or more).

A silicone resin having fewer reactive groups (eg, methyl groups) than silicone rubber has higher hardness than silicone rubber, and silica having no reactive groups has even higher hardness. In terms of mass, silica is the largest, silicone resin is the second largest, and silicone rubber is the smallest.

From the viewpoint of suppressing deformation of the unevenness of the surface when the second layer 11 comes into contact with a contacting object, silica having high hardness is most preferable as the material of the first fine particles 112, followed by silicone resin. This is because the higher the hardness of the first fine particles 112 is, the more the uneven deformation of the surface of the second layer 11 can be suppressed when the pressing pressure is applied to the surface of the second layer 11 by a contacting object. be. As a result, it is possible to suppress an increase in the contact area of the second layer 11 with the contact object and maintain the lubricity.

On the other hand, since silica has a large mass as described above, the first fine particles 112 made of silica tend to settle in the silicone rubber coating agent that is the base material in the manufacturing process of the second layer 11, and the silicone resin is made of silicone resin. Compared to the first fine particles 112, it is difficult to disperse them in the silicone rubber (second layer 11). Therefore, from the viewpoint of improving the uniformity of dispersion in the silicone rubber (second layer 11), it is preferable to use the first fine particles 112 made of silicone resin.

Therefore, in order to achieve both the maintenance of slipperiness when the second layer 11 comes into contact with a contacting object and the uniformity of dispersion of the first fine particles 112 in the base material silicone rubber, It is preferable to use the first fine particles 112 of

The average particle diameter of the first microparticles 112 is, for example, 1 μm or more and 10 μm or less. Also, the concentration (% by mass) of the first fine particles 112 in the second layer 11 is, for example, 10% by mass or more and 60% by mass or less. Here, the "average particle size" in the specification of the present application refers to that measured by a laser diffraction scattering method.

In addition, as described above, the first microparticles 112 have higher resistance to UV-C light than silicone rubber, which is the material of the base material 111 . This is because the bond energy between atoms in the molecular structure of silicone resin or silica, which is the material of the first fine particles 112, is higher than the bond energy between atoms in the molecular structure of silicone rubber.

For example, the C—H bond, which is often contained in silicone rubber, has a bond energy (approximately 4.27 eV) that is smaller than the energy of UV-C light (approximately 6.2 eV), so the bond is cut by irradiation with UV-C light. However, Si—O bonds, which are abundantly contained in the silicone resin, have bond energy (approximately 6.52 eV) greater than that of UV-C light, so the bond cannot be broken by irradiation with UV-C light.

The second fine particles 113 block UV-C light by absorbing and/or scattering titanium oxide (TiO ₂ ), carbon (C), zinc oxide (ZnO), iron oxide (Fe ₂ O ₃ ), etc. It consists of materials with properties. By shielding the UV-C light by the second fine particles 113, deterioration of the base material 111 made of silicone rubber due to the UV-C light can be suppressed. Titanium oxide as a material of the second fine particles 113 may be of an anatase type, rutile type, or brookite type, or may be a mixture of two or more. Also, niobium oxide may be added to titanium oxide to impart stability.

As described above, the average particle size of second fine particles 113 is preferably smaller than the average particle size of first fine particles 112 . By reducing the average particle size of the second fine particles 113 , the second fine particles 113 can be present in the gap spaces between the first fine particles 112 . By making the average particle size of the second fine particles 113 smaller than the average particle size of the first fine particles 112 , the second fine particles 113 are segregated around the first fine particles 112 to form the second layer 11 . The second fine particles 113 can be selectively arranged in a region where the first fine particles 112 do not exist in the in-plane direction. For example, the average particle diameter of the second fine particles 113 is set to 1/2 or less of the average particle diameter of the first fine particles 112, more preferably 1/5 or less. It can be segregated around one fine particle 112 . Although the lower limit of the average particle diameter of the second fine particles 113 is not particularly limited, the average particle diameter of the second fine particles 113 is preferably 10 nm or more from the viewpoint of availability. Here, the "average particle size" of the second fine particles 113 is measured by a laser diffraction scattering method.

When the second layer 11 is observed from the surface, the region where the first fine particles 112 do not exist (the region located between the first fine particles 112) has only the base material 111 made of silicone rubber. This is an area with low resistance to light. The inventors of the present application have found that by selectively arranging the second fine particles 113 in this region to block the UV-C light, the resistance to the UV-C light can be efficiently improved.

(Configuration of first layer)
In order to suppress deterioration due to UV-C light transmitted through the second layer 11, the first layer 10 has a layer for absorbing UV-C light, similar to the second layer 11 containing the second fine particles 113. It is preferable that the second microparticles 102 are included. In this case, as shown in FIG. 1, the first layer 10 uses silicone rubber as a base material 101 and contains second fine particles 102 dispersed in the base material 101 . As the material of the base material 101, polyethylene, chlorinated polyethylene, chloroprene rubber, polyvinyl chloride (PVC), polyurethane, or the like can also be used. Among them, silicone rubber and chloroprene rubber are preferable from the viewpoint of chemical resistance and heat resistance. When the first layer 10 is used as a sheath material, general compounding agents such as various cross-linking agents, cross-linking catalysts, anti-aging agents, plasticizers, lubricants, fillers, flame retardants, stabilizers, colorants, etc. can be an insulating material added with Also, instead of the second fine particles 102 dispersed in the base material 101, an organic ultraviolet absorber may be blended.

For the material of the second fine particles 102, the same material as the material of the second fine particles 113, such as titanium oxide or carbon, can be used. However, it is preferable that the second fine particles 102 are uniformly dispersed in the base material 101 so that the resistance of the first layer 10 to UV-C light does not vary from place to place. For this reason, the average particle diameter of the second fine particles 102 is not particularly limited, but is preferably 10 nm or more and 1 μm or less, for example. Here, the "average particle size" of the second fine particles 102 is measured by a laser diffraction scattering method.

[Second embodiment]
A second embodiment of the present invention is a cable or tube provided with an insulator composed of the laminated structure 1 according to the first embodiment. As an example, a cable used as an ultrasonic probe cable for medical use will be described below.

In recent years, the use of silicone rubber, which has excellent heat resistance and chemical resistance, as a sheath material for cables used in medical applications has been studied. However, as described above, silicone rubber has a problem of poor lubricity. Therefore, when silicone rubber is used as the material for the sheath of the cable, the cable tends to get caught on other members, and the surface of the cable tends to collect dust.

In particular, if the cable is likely to get caught on other members, for example, it becomes difficult to handle the cable that is connected to a medical device such as an ultrasonic imaging device. This is because, with an ultrasound imaging system, the ultrasound probe connected to the probe cable is inspected while being moved on the human body. because it will not be possible. Therefore, cables used for medical applications are desired to have good surface slipperiness (static friction coefficient of 0.5 or less) without stickiness.

FIG. 2 is a plan view schematically showing the configuration of the ultrasonic probe cable 2 according to the second embodiment of the invention. In the ultrasonic probe cable 2, as shown in FIG. 2, an ultrasonic probe 32 is attached to one end of the cable 20 via a boot 31 that protects this one end. On the other hand, the other end of the cable 20 is attached with a connector 33 that is connected to the main body of the ultrasonic imaging apparatus.

FIG. 3A is a radial cross-sectional view of the cable 20 of the ultrasonic probe cable 2. FIG. Inside the cable 20 , for example, electric wires 21 typified by a plurality of coaxial cables are housed, and a shield 22 such as a braided shield is provided so as to cover the plurality of electric wires 21 . A sheath 23 is provided to cover the shield 22 . Furthermore, the cable 20 is formed with a coating 24 that covers the sheath 23 described above and is in close contact with the sheath 23 .

FIG. 3(b) is a radial cross-sectional view of the ultrasonic probe cable 2 cut along the cutting line AA shown in FIG. As shown in FIG. 3B, the boot 31 is attached onto the coating 24 via an adhesive layer 34 so as to cover the coating 24 . The adhesive layer 34 is made of, for example, a silicone-based adhesive or an epoxy-based adhesive. Also, the boot 31 may be made of, for example, PVC, silicone rubber, chloroprene rubber, or the like. It preferably contains an absorbent.

The sheath 23 and the coating 24 of the cable 20 consist of the first layer 10 and the second layer 11 of the laminated structure 1 respectively. That is, the laminated structure 1 is used as the sheath 23 and the coating 24 in the cable 20 . By using the coating 24 made of the second layer 11 having excellent slipperiness, it is possible to suppress the ultrasonic probe cable 2 from being caught due to the stickiness of the surface of the sheath 23 . The thickness of the coating 24 is, for example, 3 μm or more and 100 μm or less. Illustration of the second microparticles 102 in the sheath 23 and the first microparticles 112 and the second microparticles 113 in the coating 24 is omitted.

Next, an example of a method for manufacturing the ultrasonic probe cable 2 according to this embodiment will be described. First, a plurality of (for example, 100 or more) electric wires 21 are bundled together. Then, a shield 22 is formed so as to cover the bundled multiple electric wires 21 .

Subsequently, the first layer 10 and the second layer 11 of the laminated structure 1 are sequentially formed so as to cover the shield 22, and the sheath 23 and the film 24 are formed. The sheath 23 is formed, for example, by extrusion using an extruder. The coating 24 is formed by, for example, a dipping method, a spray coating method, a roll coating method, or the like. In the dipping method, the coating 24 is formed on the surface of the sheath 23 by pulling up the ultrasonic probe cable 2 formed up to the sheath 23 through the liquid coating material. This dipping method is superior to the spray coating method and the roll coating method in terms of the uniformity of the film thickness of the coating 24 formed.

The liquid coating agent used in the dipping method is liquid silicone rubber containing first fine particles 112 and second fine particles 113, and contains a solvent such as n-heptane. By adjusting the content of the first fine particles 112 and the second fine particles 113 contained in the liquid coating agent, the content of the first fine particles 112 and the second fine particles 113 contained in the coating 24 is controlled. be able to.

As another example of a cable or tube provided with an insulator composed of the laminated structure 1, the configuration of a tube (hollow tube) used for medical purposes such as a catheter will be described below.

4A to 4C are radial cross-sectional views of a medical tube according to a second embodiment of the present invention. A medical tube 40 a shown in FIG. 4( a ) has an outer coating 42 on the outer surface 41 a of the tube body 41 . A medical tube 40 b shown in FIG. 4( b ) has an inner coating 43 on the inner surface 41 b of the tube body 41 . A medical tube 40c shown in FIG. 4(c) has an outer coating 42 and an inner coating 43 on an outer surface 41a and an inner surface 41b of a tube body 41, respectively.

As exemplified by medical tubes 40a, 40b, and 40c, the tube according to the present embodiment includes a tube body 41, an outer coating 42 covering the outer surface 41a of the tube body 41, and an inner surface 41b of the tube body 41. It has an overlying inner coating 43 or both an outer coating 42 and an inner coating 43 . The tube body 41 of the medical tubes 40 a , 40 b , 40 c consists of the first layer 10 of the laminated structure 1 , and the outer coating 42 and the inner covering 43 consist of the second layer 11 of the laminated structure 1 .

Since the tube according to the present embodiment has excellent lubricity on the inner surface and the outer surface, for example, when an instrument is inserted into the tube and used, such as a medical tube such as a catheter, the instrument can be smoothly moved. insertion/removal is possible. In addition, the tubes according to the present embodiment include a tube set for endoscopic surgical instruments, a tube set for ultrasonic surgical instruments, tubes for blood analyzers, piping in oxygen concentrators, artificial dialysis blood circuits, artificial heart-lung circuits, endotracheal tubes, and the like. can be used for

(Effect of Embodiment)
According to the laminated structure 1 according to the first embodiment, since the second layer 11 contains the first fine particles 112, the surface is excellent in slipperiness. 2 fine particles 113 are segregated, the resistance to UV-C light is excellent. Further, according to the ultrasonic probe cable 2 and the medical tubes 40a, 40b, 40c, etc. according to the second embodiment, since the laminated structure 1 is used as an insulator, the surface is excellent in slipperiness. Excellent resistance to UV-C light.

In the above-described first embodiment, silicone rubber is used as the material of the base material 111 in the second layer 11 of the laminated structure 1, but rubber other than silicone rubber such as chloroprene rubber may be used instead of silicone rubber. A similar effect can be obtained by using a component.

(Production of laminated structure 1)
Four kinds of samples (Samples A1 to A4) were prepared for verifying the UV-C light shielding effect of the second layer 11 of the laminated structure 1 . First, 200 coaxial cables with a diameter of about 0.25 mm were twisted together and covered with a braided wire to prepare a cable core. Subsequently, using an extruder, the outer periphery of the cable core was extruded and covered with a sheath material at a speed of 5 m/min to form a sheath 23 having a thickness of 0.8 mm as the first layer 10 of the laminated structure 1. (cable outer diameter about 8 mm). Here, PVC, which is generally used, was used as the sheath material of sample A1. As the sheath material of samples A2 to A4, a color batch containing titanium oxide (a mixture of "KE-color-W" and "KE-174-U" manufactured by Shin-Etsu Chemical Co., Ltd.) was used. Mixed so that the Ti concentration analyzed by an energy dispersive X-ray spectrometer (EDS) mounted on a scanning electron microscope (SEM) (average value in a measurement area of 125 μm wide × 95 μm long) was 0.12% by mass. did. Through the steps up to this point, the samples A1 and A2 without the film 24 as the second layer 11 of the laminated structure 1 were produced.

Subsequently, a material for forming the coating 24 of sample A3 was prepared. An addition reaction type silicone rubber coating agent (trade name: SILMARK-TM, manufactured by Shin-Etsu Chemical Co., Ltd.) was prepared as a rubber component for the base material 111 . As the first fine particles 112, silicone resin fine particles (trade name: X-52-1621, manufactured by Shin-Etsu Chemical Co., Ltd.) having an average particle size of 5 μm were prepared. For 100 parts by mass of this rubber component, 120 parts by mass of silicone resin fine particles, 600 parts by mass of toluene as a solvent for viscosity adjustment, and 8 parts by mass of a cross-linking agent (trade name: CAT-TM, manufactured by Shin-Etsu Chemical Co., Ltd.). , 0.3 parts by mass of a curing catalyst (trade name: CAT-PL-2, manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed to prepare a coating solution in which the ratio of the first fine particles 112 to the coating 24 was 55% by mass. . Note that the content of the first fine particles 112 in the coating 24 was calculated on the assumption that the coating agent was cured without substantially reducing its mass (substantially equivalent to the mixing mass ratio).

Subsequently, the surface of the sheath 23 provided on the cable core was washed. Thereafter, the cable core provided with the sheath 23 was immersed in the above coating solution by a dip coating method to form a coating film made of silicone rubber on the surface of the sheath. After that, the coating film was sufficiently dried and cured at a temperature of 150° C. to form a coating film 24 having an uneven surface. The thickness of the film 24 of the obtained sample A3 was 15 μm. Sample A3 was produced through the above steps.

Next, a material for forming the coating 24 of sample A4 was prepared. For the coating 24 of the sample A4, in addition to the same rubber component as the base material 111 and the silicone resin fine particles as the first fine particles 112 used for the coating 24 of the sample A3, the second fine particles 113 are Titanium oxide (anatase-type TiO ₂ ) fine particles with a particle size of 250 nm were prepared. Then, with respect to 100 parts by mass of the rubber component, 120 parts by mass of silicone resin fine particles, titanium oxide fine particles, 600 parts by mass of toluene as a solvent for viscosity adjustment, a cross-linking agent (trade name: CAT-TM, Shin-Etsu Chemical Co., Ltd. company) and 0.3 parts by mass of a curing catalyst (trade name: CAT-PL-2, manufactured by Shin-Etsu Chemical Co., Ltd.). A coating solution was prepared in which the ratio of the second fine particles 113 to the coating 23 was a predetermined concentration. The concentration of the titanium oxide fine particles, which are the second fine particles 113, is determined by an energy dispersive X-ray spectrometer (EDS) mounted on a scanning electron microscope (SEM). Adjustment was made so that the concentration of titanium (average value in the measurement area) was 0.6% by mass. Also, the content of the first fine particles 112 in the coating 24 was calculated on the assumption that the coating agent cured without substantially reducing its mass (substantially equivalent to the mixing mass ratio).

Subsequently, in the same manner as the coating 24 of sample A3, the surface of the sheath 23 was washed, a coating film was formed by a dip coating method, and the coating film was dried and cured to form a coating 24 having unevenness on the surface. formed. The thickness of the film 24 of the obtained sample A4 was 15 μm. Sample A4 was produced through the above steps.

(Verification of UV-C light shielding effect)
In order to verify the UV-C light shielding effect of the second layer 11 of the laminated structure 1, tensile tests were performed on samples A1 to A4 before and after UV-C light irradiation. First, the sheath 23 of the cable-shaped samples A1 to A4 produced by the above method (the sheath 23 covered with the film 24 in the samples A3 and A4) was cut along the length direction, and the inside of the sheath 23 was cut. The contents were removed and the sheath 23 was opened. Then, the opened sheath 23 was punched out with a No. 6 dumbbell to prepare a dumbbell test piece (thickness: 0.8 mm). Here, the dumbbell test pieces formed from the sheaths 23 of the samples A1, A2, A3 and A4 (the sheaths 23 covered with the films 24 in the samples A3 and A4) are referred to as samples B1, B2, B3 and B4, respectively. Table 1 below shows the configurations of samples B1 to B4.

The tensile test is a test specified in "JIS K6251 (1994)", and was performed on the above samples B1 to B4 under the conditions of an environmental temperature of 15 to 35 ° C., an environmental humidity of 28 to 65 RH%, and atmospheric pressure. . In addition, UV-C light irradiation was performed using a storage cabinet with a germicidal lamp (Daishin Kogyo Co., Ltd. DM-5, lamp GL-10), with an internal temperature of 25 to 40 ° C., an internal humidity of 28 to 65%, and a The conditions were an internal pressure of 1 atm (atmospheric pressure), a wavelength of 253.7 nm, an illuminance of 1.3 mW/cm ² , and an irradiation time of 100 hours and 200 hours. UVC-254A manufactured by MK Scientific was used as an illuminometer.

FIG. 5(a) is a graph showing the results of the tensile test of sample B1. "Unirradiated" in FIG. 5(a) indicates the sample B1 in a state not irradiated with UV-C light, and "after irradiation" indicates the sample B1 after being irradiated with the above UV-C light for 200 hours. showing. As shown in FIG. 5(a), after irradiation with UV-C light, the strength (magnitude of stress when the substrate breaks) and elongation are smaller than before irradiation, and sample B1 is UV- It was confirmed that the irradiation of the C light causes deterioration (deterioration that makes it easier to break). Further, since the sample B1 was gray PVC, it was visually confirmed that the sample B1 was discolored to a yellowish color by irradiation with UV-C light. The elongation of 100% means that the length of the dumbbell test piece has doubled from its initial length.

FIG.5(b) is a graph which shows the result of the tension test of sample B2. "Unirradiated" in FIG. 5(b) indicates the sample B2 in a state not irradiated with the UV-C light, and "after irradiation" indicates the sample B2 after being irradiated with the UV-C light for 200 hours. showing. As shown in FIG. 5(b), the strength and elongation after irradiation with UV-C light are smaller than those before irradiation, and it is possible that sample B2 deteriorates (changes) due to irradiation with UV-C light. confirmed. No discoloration due to irradiation with UV-C light was visually observed in sample B2 (white) made of silicone rubber. On the other hand, when compared with the graph of FIG. 5(a), it can be seen that the degree of deterioration of silicone rubber due to irradiation with UV-C light is greater than that of PVC.

Although sample B2 contains TiO ₂ fine particles as second fine particles that absorb UV-C light, the concentration thereof is low (the Ti concentration in the sheath 23 is 0.12% by mass). It is considered that the resistance to -C light was hardly affected. Moreover, since the sample B2 does not have a film corresponding to the second layer 11, the surface lubricity is inferior to the samples B3 and B4.

FIG. 6(a) is a graph showing the results of the tensile test of sample B3. "Unirradiated" in FIG. 6(a) indicates the sample B3 in a state not irradiated with the UV-C light, and "after irradiation" indicates the sample B3 after being irradiated with the UV-C light for 200 hours. showing. As shown in FIG. 6(a), the strength and elongation after irradiation with UV-C light are smaller than those before irradiation, confirming that sample B3 deteriorates due to irradiation with UV-C light. . Further, for sample B3 (white), similarly to sample B2, no discoloration due to irradiation with UV-C light was visually observed.

According to FIG. 6A, cracks are generated in the coating 23 corresponding to the second layer 11 when the elongation exceeds 50%. The coating 23 of sample B3 contains silicone resin fine particles as the first fine particles 112 having excellent resistance to UV-C light. It is considered that cracks were generated.

FIG.6(b) is a graph which shows the result of the tension test of sample B4. "Unirradiated" in FIG. 6(b) indicates the sample B4 in a state not irradiated with UV-C light, and "after irradiation" indicates the sample B4 after being irradiated with the above UV-C light for 200 hours. showing. As shown in FIG. 6(b), the strength and elongation are almost equal before and after UV-C light irradiation, confirming that the deterioration of sample B4 due to UV-C light irradiation is effectively suppressed. was done. Further, for sample B4 (white), similarly to sample B2, no discoloration due to irradiation with UV-C light was visually observed.

Comparing the test results of sample B4 with the test results of sample B3, the titanium oxide fine particles as the second fine particles contained in the coating corresponding to the second layer 11 block UV-C light and suppress deterioration. I understand that.

FIG. 7(a) is a graph showing the relationship between the irradiation time of UV-C light and the stress at breakage of the substrate for samples B1 to B4. FIG. 7(b) is a graph showing the relationship between the irradiation time of UV-C light and the elongation at break of the substrate of samples B1 to B4.

According to FIGS. 7A and 7B, the sample B3, which does not contain titanium oxide fine particles as the second fine particles in the coating corresponding to the second layer 11, has , the strength and elongation are reduced. On the other hand, Sample B4, which contains titanium oxide fine particles as the second fine particles in the coating corresponding to the second layer 11, shows no change in strength and elongation even if the UV-C light irradiation time is increased. Also, sample B4 is inferior to sample B1 in elongation before irradiation with UV-C light, but is superior to sample B1 in elongation after irradiation with UV-C light for 200 hours. These results also show that the titanium oxide fine particles contained in the coating of sample B4 can suppress the progression of deterioration due to UV-C light.

A Raman mapping analysis was performed to examine the distribution state of the second fine particles 113 in the second layer 11 of the laminated structure 1 . In the Raman mapping analysis, Raman scattering measurement is performed while scanning the surface of the sample with a laser, and the information obtained from the Raman scattering spectrum at each measurement point is mapped two-dimensionally. Raman mapping analysis was performed using samples before UV-C light irradiation.

Tables 2 and 3 below show the measurement conditions and mapping conditions for Raman scattering measurement, respectively. The Raman scattering measurement was performed using a RAMANforce Standard VIS-NIR-HS manufactured by Nanophoton Co., Ltd. The Raman scattering measurement was carried out under an environment with an environmental temperature of 15 to 35° C., an environmental humidity of 25 to 65 RH%, and atmospheric pressure.

The mapping analysis according to this example was performed on the surfaces of four types of sheet-like silicone rubber films (referred to as samples C1 to C4) as the second layer 11 . All of the samples C1 to C4 include silicone rubber as the base material 111, silicone resin fine particles having an average particle size of about 2 μm as the first fine particles 112, and anatase having an average particle size of about 250 nm as the second fine particles 113. It contains titanium oxide microparticles, mainly containing _TiO2 microparticles of the type. The content of silicone resin particles in samples C1 to C4 is all 60% by mass. The content of silicone resin fine particles in Samples C1 to C4 was calculated on the assumption that the silicone rubber coating agent cured with almost no weight loss (almost equivalent to the blending weight ratio). Specifically, the mass of the silicone resin microparticles is divided by the total mass of the silicone resin microparticles, the titanium oxide microparticles and the silicone rubber and expressed as a percentage.

Table 4 below shows the silicone resin particles as the first fine particles 112, the silicone resin concentration in each sample, the average particle size of the titanium oxide fine particles as the second fine particles 113, and the Ti concentration is shown. The Ti concentration in the table was determined by SEM-EDS (average value in a measurement area of 125 μm wide×95 μm long). Note that the sample C1 corresponds to the sample A4 (B4).

Samples C1 to C4 differ in the blending amount of titanium oxide fine particles as second fine particles 113 . The Ti concentrations (SEM-EDS evaluation results) of samples C1, C2, C3, and C4 are 0.6% by mass, 1.1% by mass, 1.5% by mass, and 4.4% by mass, respectively.

FIG. 8 shows a Raman scattering spectrum measured at a certain point on the sample C1 as an example of the measured Raman scattering spectrum. The peak (referred to as the first peak) near about 640 cm ⁻¹ (eg, 640±20 cm ⁻¹ ) in the Raman scattering spectrum is mainly derived from the lattice vibration Eg of anatase TiO ₂ (anatase TiO ₂ fine particles) is a particularly intense peak in the scattering spectrum of the titanium oxide fine particles, and the peak near about 2915 cm ^-1 (for example, 2915±33 cm ^-1 ) (referred to as the second peak) is , which is a particularly intense peak in the scattering spectrum of the silicone resin, which is derived from the CH stretching of the silicone resin. In the Raman mapping analysis according to this example, the intensities of these first and second peaks were used to map the distribution of titanium oxide fine particles and silicone resin fine particles. In the case where the titanium oxide fine particles mainly contain rutile-type TiO ₂ fine particles, a peak near about 445 cm ⁻¹ (for example, 445±45 cm ⁻¹ ) derived from lattice vibration Eg is used as the first peak. is preferred. Further, when the titanium oxide fine particles mainly contain brookite-type TiO ₂ fine particles, it is preferable to use a peak near about 150 cm ⁻¹ (for example, 150±15 cm ⁻¹ ) as the first peak.

FIGS. 9A, 10A, 11A, and 12A are mapping images of samples C1, C2, C3, and C4 obtained by mapping analysis, respectively. The size of these mapping images (mapping area) is 22.5 μm×22.5 μm.

Mapping analysis was performed using analysis software Raman Viewer Ver.4.5.54 manufactured by Nanophoton Co., Ltd. 9(a), 10(a), 11(a), and 12(a), the shading of the regions showing the titanium oxide fine particles is made darker as the intensity of the first peak increases. , intensity was set within the range of 20-3500. A value within the range of 1760 to 3500 was set as the presence of titanium oxide fine particles. In addition, the density of the region showing the silicone resin fine particles was set within the range of intensity 400 to 3000 so that the intensity of the second peak increased as the intensity of the second peak increased. A value within the range of 1700 to 3000 was set as the presence of silicone resin microparticles. A region in which neither the Raman peak indicating the silicone resin fine particles nor the titanium oxide fine particles is observed, that is, the silicone rubber region which is the base material 111 is observed in a different color from these regions.

9(a), 10(a), 11(a), and 12(a), the titanium oxide fine particles segregate around the silicone resin fine particles, and the silicone resin fine particles do not exist in the region (silicone It can be seen that the area located between the resin particles) is efficiently filled. This is because the average particle size of the titanium oxide fine particles is smaller than the average particle size of the silicone resin fine particles (for example, 1/2 or less, more preferably 1/5 or less). In addition, as the amount of the titanium oxide fine particles added increases, the proportion of the region occupied by the titanium oxide fine particles in the region where the silicone resin fine particles are not present increases, and when the Ti concentration is 1.5% by mass or more, silicone Titanium oxide microparticles occupy almost the entire region in the region where resin microparticles do not exist (region with low resistance to UV-C light).

That is, in the second layer 11, since the titanium oxide fine particles are preferentially present in the regions where the silicone resin fine particles are not present, the regions where the silicone resin fine particles are present (FIGS. 9(a), 10(a), In FIGS. 11(a) and 12(a), the intensity of the first peak in the circular white region: region A) is the region where the silicone resin fine particles are not present (the region located between the silicone resin fine particles: region It has a region where the intensity is smaller than the intensity of the first peak in B). Thus, in the second layer 11, the titanium oxide fine particles are not uniformly dispersed, and the titanium oxide fine particles are segregated around the silicone resin fine particles.

FIGS. 9(b), 10(b), 11(b) and 12(b) are respectively FIG. 9(a), FIG. 10(a), FIG. 11(a) and FIG. 12(a). It is a binarized analysis image obtained by binarizing the mapping image of .

This binarization analysis was performed by the "area ratio analysis" function of the analysis software Raman Viewer Ver.4.5.54. Also, in this binarization analysis, the integrated intensity of the first peak integration range 38.7 cm ^-1 is applied to the calculation as the intensity of the first peak, and the integration range of the second peak 35.2 cm ^-1 The integrated intensity was applied in the calculation as the intensity of the second peak. In Raman Viewer Ver.4.5.54, the intensity calculation method in binarization analysis is called area calculation.

According to the binarized analysis images shown in FIGS. 9(b), 10(b), 11(b), and 12(b), the area of the titanium oxide fine particles and the area other than the titanium oxide fine particles ( That is, the ratios of the total area of silicone resin fine particles and silicone rubber) are 6.4 to 93.6, 12.8 to 87.2, 22.7 to 77.3, and 35.2 to 64.8, respectively. .

From the above results, when the ratio of the area of the titanium oxide fine particles to the total area of the titanium oxide fine particles and the silicone resin fine particles in the binarized analysis image performed under the above conditions is 22.7% or more, the silicone It was found that titanium oxide particles occupy almost all of the area where no resin particles are present, and that the second layer 11 has excellent resistance to UV-C light. The conditions for the second layer 11 to have excellent resistance to UV-C light include the case where the silicone resin fine particles as the first fine particles 112 are changed to other fine particles such as silica fine particles, It is considered that this holds true even when the titanium oxide fine particles as the fine particles 113 are changed to other fine particles such as carbon fine particles. From the viewpoint of reducing the coefficient of static friction, it is necessary to have a region where a certain amount of silicone resin fine particles are present. The upper limit of the ratio of is preferably 50% or less.

(Summary of embodiment)
Next, technical ideas understood from the embodiments described above will be described with reference to the reference numerals and the like in the embodiments. However, each reference numeral and the like in the following description do not limit the constituent elements in the claims to the members and the like specifically shown in the embodiment.

[1] A first layer (10) as a base material, a rubber component (111), first fine particles (112) for imparting unevenness to the surface, and a second layer for shielding UV-C light. A second layer (11) formed from a rubber composition containing fine particles (113) and laminated on the first layer (10), and a Raman scattering measurement of the second layer (11) When the Raman mapping analysis was performed on the first peak derived from the vibration of the second fine particles (113) contained in the obtained Raman scattering spectrum, the region where the first fine particles (112) were present was found to be the A laminated structure (1) having a region where the intensity of the first peak is high in a region where the first fine particles (112) do not exist.

[2] The above [1], wherein the rubber component (111) is a silicone rubber, and the first fine particles (112) are made of a Si-containing material having higher resistance to UV-C light than the silicone rubber. ], the laminated structure (1).

[3] The laminated structure (1) according to [1] or [2] above, wherein the first fine particles (112) are silicone resin fine particles and/or silica fine particles.

[4] The laminated structure (1) according to any one of [1] to [3] above, wherein the second fine particles (113) are titanium oxide fine particles.

[5] The laminated structure according to [4] above, wherein the second layer has a Ti concentration of 1.5% by mass or more.

[6] A cable (20) comprising an insulator comprising the laminated structure (1) according to any one of [1] to [5] above.

[7] Tubes (40a, 40b, 40c) comprising an insulator comprising the laminated structure (1) according to any one of [1] to [5] above.

[8] A first layer (10) having a silicone rubber as a base material, and a silicone rubber as a base material (111) laminated on the first layer (10) to provide unevenness to the surface and a second layer (11) comprising second microparticles (113) for absorbing UV-C light, said first microparticles (112) comprising said Made of a Si-containing material having higher resistance to UV-C light than silicone rubber, the average particle size of the second fine particles (113) is 1/1 of the average particle size of the first fine particles (112) 2 or less, laminated structure (1).

Although the embodiments and examples of the present invention have been described above, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the invention. Moreover, the embodiments and examples described above do not limit the invention according to the scope of the claims. Also, it should be noted that not all combinations of features described in the embodiments and examples are essential to the means for solving the problems of the invention.

1 Laminated Structure 10 First Layer 111 Base Material 112 First Microparticle 113 Second Microparticle 11 Second Layer 2 Ultrasonic Probe Cable 20 Cable 23 Sheath 24 Coating 40a, 40b, 40c Medical Tube 41 Tube Body 42 Outer coating 43 Inner coating

Claims (7)

a first layer serving as a base material;
A second layer formed from a rubber composition containing a rubber component, first fine particles for imparting unevenness to the surface, and second fine particles for shielding UV-C light, and laminated on the first layer. layer and
with
When Raman mapping analysis is performed on the first peak derived from the vibration of the second fine particles contained in the Raman scattering spectrum obtained by Raman scattering measurement of the second layer, the first fine particles are present. Having a region where the intensity of the first peak is greater in the region where the first fine particles are not present than in the region,
Laminated structure. The rubber component is silicone rubber,
The first fine particles are made of a Si-containing material having higher resistance to UV-C light than the silicone rubber,
The laminate structure according to claim 1. The first microparticles are silicone resin microparticles and/or silica microparticles,
The laminate structure according to claim 1 or 2. wherein the second fine particles are titanium oxide fine particles;
The laminate structure according to any one of claims 1 to 3. Ti concentration of the second layer is 1.5% by mass or more,
The laminate structure according to claim 4. An insulator comprising the laminated structure according to any one of claims 1 to 5,
cable. An insulator comprising the laminated structure according to any one of claims 1 to 5,
tube.

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