JP2003102828A - Shape memory thin film composed of strongly hydrogen absorbing alloy, shape memory composite material composed of strongly hydrogen absorbing alloy, and soft catheter for medical use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape memory thin film that is composed of a strongly hydrogen absorbing alloy, can be deformed by overcoming the resistance from the surrounding bio-tissue of a bodily temperature area of a human being by revealing a strong shape memory effect, has good bio-compatibility and a human body-friendly soft property, and can reveal a shape memory effect even when the thin film is not heated, and to provide a shape memory composite material composed of the strongly hydrogen absorbing alloy and a soft catheter for medical use. SOLUTION: The shape memory thin film composed of the strongly hydrogen absorbing alloy is composited by diffusing fine LaNix-based alloy particles in a polymer material.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a strong hydrogen storage alloy shape memory thin film that exhibits a shape memory effect in a temperature range slightly higher than room temperature, particularly in a temperature range of human body temperature, and can be used in the medical field. The present invention relates to a strong hydrogen storage alloy shape memory composite material and a medical soft catheter.

[0002]

2. Description of the Related Art Recently, in clinical clinical practice, various treatments and tests are performed by inserting a catheter into a living body and remotely controlling the distal end portion thereof. In such a medical catheter, medical personnel request a small power source that can freely move the tip portion.

Various types of power sources for medical catheters have been proposed so far, but among them, shape memory alloys are drawing attention because of their small size, light weight and simple structure.

[0004]

However, since the conventional shape memory alloy material exerts a small force when the shape memory effect is exhibited, it cannot be deformed against the restraining force of the tissues surrounding the living body. Or, the amount of deformation becomes insufficient. For example, it cannot be used for treatment that requires a large deformation such as bending the tip of the catheter by 90 degrees or more.

As a medical catheter, it exhibits a shape memory effect in the temperature range of human body temperature and has good biocompatibility,
No shape memory alloy material has been proposed so far, which has soft properties that are gentle to the human body and also has all of the properties that exert a shape memory effect without applying heat.

The present invention has been made in order to solve the above-mentioned problems, and exhibits a strong shape memory effect in the temperature region of human body temperature to overcome the resistance of surrounding living tissues and deform. A strong hydrogen storage alloy shape memory thin film, a strong hydrogen storage alloy shape, which has a good biocompatibility, has a soft property that is kind to the human body, and can exert a shape memory effect without applying heat. It is an object to provide a memory composite material and a medical soft catheter.

[0007]

A strong hydrogen storage alloy shape memory thin film according to the present invention is laminated on a substrate by using either a physical vapor phase method, a chemical vapor phase method or a physicochemical vapor phase method. It is characterized in that it is made of the LaNix-based alloy obtained as described above.

The strong hydrogen storage alloy shape memory composite material according to the present invention is characterized in that fine particles of LaNix alloy are dispersed in a polymer material to form a composite.

The above alloy thin film or the dispersion alloy in the composite material preferably has a stoichiometric coefficient x in the range of 4 to 7, and is further composed of either LaNi ₅ alloy or LaNi _6.5 alloy. preferable.

Furthermore, the dispersion alloy in the alloy thin film or composite material is LaNixCo with Co added as the third element.
It is preferably composed of y alloy. In this case, it is preferable that the stoichiometric coefficient x be in the range of 3 to 4 and the stoichiometric coefficient y be in the range of 1.5 to 2.5. Among the LaNiCo alloys, LaNi _3.3 Co _2.1
The alloy thin film having the above composition is the best.

In the case of a LaNi-based alloy or LaNiCo-based alloy thin film, its thickness is preferably 1 μm or less. This is because if the film thickness exceeds 1 μm, the thin film may collapse during repeated storage and release of hydrogen and the shape may not be maintained.

Hydrogen storage alloys represented by LaNi alloys show a maximum volume expansion of 24% when absorbing and releasing hydrogen,
Furthermore, the expansive force destroys itself and shows a force enough to make it fine.

Therefore, a composite material in which a hydrogen storage alloy powder typified by LaNi ₅ alloy is dispersed in silicone rubber, which is one of polymer materials that does not damage the living body, is further bonded with silicone rubber without any additive. Then, a bipolymer was produced and used as a medical hydrogen storage alloy dispersed shape memory material.

The alloy fine particles are preferably fine particles having an average particle size in the range of 25 to 40 μm obtained by causing the alloy lump or the alloy thin film to occlude by excessively absorbing hydrogen. The alloy fine particles may be manufactured by a gas atomizing method or a mechanical grinding method such as a ball mill.

In general, the smaller the particle size of the alloy fine particles, the larger the specific surface area, so the hydrogen absorbing capacity is increased, which is advantageous in obtaining a large deformation force. However, it is generally difficult to produce ultrafine particles of a hydrogen storage alloy having an average particle size of less than 1 μm (micronization due to hydride formation is relatively easy if the particle size is 1 μm or more, but less than 1 μm With this particle size, pulverization due to hydride formation is less likely to occur), and even if it can be manufactured, the manufacturing cost increases significantly, so the lower limit of the average particle size of the alloy fine particles is preferably 1 μm.

On the other hand, when the average particle size exceeds 40 μm, the specific surface area decreases, the hydrogen storage amount decreases, the deformation force decreases, and uniform kneading with the polymer becomes difficult. The upper limit of the diameter is preferably 40 μm. In the examples described later, the particle size of the alloy fine particles is conveniently set to 25 to 40 μm in order to compare the LaNi ₅ alloy and the LaNiCo hydrogen storage alloy. This is because pulverization due to hydride formation is extremely easy up to a particle diameter of about 25 μm.

The polymeric material preferably comprises silicone rubber. This is because silicone rubber is substantially harmless to the human body and has good biocompatibility. In addition to silicone rubber, it is also possible to use a polymer material that transmits hydrogen, does not damage the human body, and does not elute harmful substances.

The alloy fine particles have a stoichiometric coefficient x of 4
It is preferably in the range of 7 to 7, and more preferably made of either a LaNi ₅ alloy or a LaNi _6.5 alloy.

The fine particles of the alloy are LaN further containing Co.
It is preferably made of an ixCoy alloy. In this case,
It is preferable that the stoichiometric coefficient x is in the range of 3 to 4 and the stoichiometric coefficient y is in the range of 1.5 to 2.5, and the particles are LaNi _3.3 Co _2.1 alloy particles. Is more preferable.

The medical soft catheter according to the present invention comprises:
A first element having a hollow portion through which hydrogen gas or a hydrogen-containing gas flows, and made of the above-mentioned strong hydrogen storage alloy dispersed shape memory composite material; and hydrogen gas flowing through the hollow portion of the first element, or A second element having a hollow part through which a hydrogen-containing gas flows and made of a polymer material adhered to the first element.

The order of gas flow is as follows:
It is preferable that the gas is allowed to flow through the hollow part of the element, and then the gas is allowed to flow (return) to the hollow part of the second element, but the gas may be allowed to flow in the reverse order.

Further, the first and second elements are formed in a semi-cylindrical shape, and the ventral planes of the semi-cylindrical first and second elements are bonded to form a cylindrical element assembly. It is preferable to bundle a plurality of the above. By bundling a plurality of elements in this way, the deformation force is further enhanced.

[0023]

Various preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) (Hydrogen Storage Alloy Shape Memory Thin Film) The flash vapor deposition apparatus shown in FIG. 1 was used to prepare a hydrogen storage alloy shape memory thin film sample. The flash vapor deposition apparatus 1 is surrounded by a vacuum container 2 that is evacuated via an exhaust path 3. A flash heating unit 4 is provided below the vacuum container 2, and a sample holder 20 is provided above the container 2. The flash heating unit 4 includes a heater 5 and a hopper 10. The heater 5 is supported by a plurality of posts 7 via insulating members 8 and 9, and is supplied with power from a power source (not shown). The raw material powder 6 is stored in the hopper 10, and an appropriate amount of the raw material powder 6 is dropped from the hopper 10 onto the heater 5.

The sample holder 20 includes a motor 21 and a holder 2.
3, a cover 24 is provided. This sample holder 20 is
It is movably supported by an elevating mechanism having a guide post 17, an elevating member 18, and a support plate 19. A plurality of substrates 29 are held by the holder 23 of the sample holding unit 20. In this case, the three or six substrates 29 are attached to the holder 23.
Held in. The drive shaft 22 of the motor 21 is the holder 2
3, the holder 23 is rotated and moved.

In the flash vapor deposition apparatus 1, the heater 5
When a predetermined component and a predetermined amount of the raw material powder 6 are dropped from the hopper 10 to a high temperature state, the raw material powder 6 instantly becomes a metal vapor and is vapor-deposited on the surface of the substrate 29 held by the holder 23, so that A thin film of

Example 1 A LaNi-based alloy thin film having a thickness of 1 μm or less was produced on a polyimide film substrate under the following conditions using the above flash vapor deposition apparatus.

Degree of ultimate vacuum: 10 ^-3 Pa or less Substrate material: Polyimide film Substrate thickness: 11 μm Sample temperature: Room temperature (however, the substrate temperature is 356 K due to radiant heat)
Temperature rises to (83 ℃). ) Powder composition: average film thickness of LaNi ₅ alloy thin film: 0.2 μm Vapor-deposited alloy thin film composition: LaNi _{6.5 In} addition to polyimide film, polymer thin film such as paraffin or silicone single crystal or metal thin film should be used as the substrate. Good.

The produced hydrogen storage thin film is Energy Dispersio
n X-ray Spectroscopy
As a result of analyzing the composition by using, it was found to be a hydrogen storage thin film of LaNi _6.5 . The produced hydrogen storage alloy shape memory thin film was placed in a reaction tube made of stainless steel (SUS316) in an atmosphere of high purity hydrogen (5N) (or more), and was stored for about 50b.
The initial activation operation was performed on the hydrogen storage alloy in the sample at a hydrogen pressure of ar.

The activated sample was placed in a heating vessel 41 of a hydrogen storage shape memory effect measuring apparatus 40 comprising a glass reaction tube shown in FIG. 2, and evacuation and hydrogenation were alternately repeated several times. After that, shape displacement (Y / X) at each sample temperature
Was measured using a video recorder 49. Heating container 4
1 is equipped with a heater (not shown) (not shown)
Can be heated to a temperature of 0 ° C. to 90 ° C. Inside the heating container 41, a pipe 43 penetrating through the lid 42 is used to connect the rotary pump 45, the hydrogen gas cylinder 46, the thermometer 47, the pressure gauge 48 to the valves 44a-4.
4c communicate with each other. The thermometer 47 detects the temperature of the sample 32 in the container, and the pressure gauge 48
Is for detecting the pressure of hydrogen gas introduced from the gas cylinder 46 into the container 41.

The change in shape of the sample was measured as shown in FIG. 3, where the horizontal length X and the vertical length of the sample 32 were Y, and the ratio (Y / X) between them was obtained.

The result of measuring the shape of the sample by the measuring device 40 will be described with reference to FIG. 4 (a), (b) and (c) are photographs showing the shape deformation due to the introduction of hydrogen at a sample temperature of 303.15K. Before hydrogenation (activation), as shown in FIG. 4 (a), the sample was bent so that the polyimide film substrate was on the inside and the LaNi _6.5 alloy thin film was on the outside due to the effect of stress due to vapor deposition. It is in. After evacuation, the shape of the sample is shown in Fig. 4.
(B) of FIG. Here, the sample temperature 30
By introducing hydrogen gas at 3.15 K under a pressure of 3.86 bar, the thin film further expanded in volume, and as shown in FIG. 4C, the shape was further deformed toward the polyimide film side. This shape change can be explained as being caused by the LaNi _6.5 alloy thin film exhibiting volume expansion due to hydrogen absorption.

In FIG. 8, the horizontal axis represents time t from the start of hydrogen introduction.
(Sec) is taken, and the vertical axis represents the shape displacement (Y / X), and is a characteristic diagram showing the results of examining the shape change of the LaNi _6.5 alloy thin film when hydrogen is introduced at each temperature. In the figure, the triangular plot shows the result of the temperature of 296.15K, the square plot shows the result of the temperature of 303.15K, and the rhombic plot shows the result of 3.
The result of 11.15K, the circle plot shows the temperature of 316.15.
The results of K are shown respectively. The hydrogen partial pressure P is 3.86.
It was set to bar (constant). As is clear from this figure, it was confirmed that the LaNi _6.5 thin film vacuum-deposited on the polyimide film had an increased amount of shape displacement as the hydrogen introduction time increased at each sample temperature.

In FIG. 9, the horizontal axis represents the reciprocal of temperature (1 / T) when the shape displacement (Y / X) of the LaNi _6.5 thin film sample becomes 0.007, and the vertical axis represents the hydrogen introduction from the start. It is the characteristic view which took the reciprocal of time (1 / t) and investigated the correlation of both. When the apparent activation energy was obtained from the slope of the straight line in the figure, it was found that Ea = 11.2 kal / mol. This roughly corresponds to the value of the activation energy for diffusion of hydrogen in the metal.

As described above, it was confirmed that the LaNi-based alloy thin film of the present embodiment exhibits a shape memory effect by changing the temperature or the introduced hydrogen pressure (by absorbing or releasing hydrogen). .

As the deformation output when the shape memory effect is exhibited, the stress (σ _L ) is calculated from the total cross-sectional area of the sample to be 1000 kPa, and only the hydrogen storage alloy thin film which is the driving source due to the strain change is calculated. The stress (σ
_{When t} ) was calculated, a large force of 56193.5 kPa could be measured.

(Second Embodiment) (Hydrogen storage alloy shape memory composite material) Composite material A in which hydrogen storage alloy powders of various compositions are dispersed and fixed in silicone rubber.
A bipolymer shape memory material was prepared by adhering a silicone rubber simple substance (non-added silicone rubber) B on top of the alloy, and the shape memory effect was measured.

(Example 2) (LaNi-based hydrogen storage alloy shape memory composite material) Example 2
The method for producing the sample will be described.

As sample A, hydrogen storage alloy powder represented by LaNi ₅ alloy (particle size: 25-40 μm) 0.61
A composite material having a shape of 30 × 5 × 1 mm ³ (length × width × thickness) was prepared by sufficiently kneading and dispersing 3 g and 0.095 g of silicone rubber (product name “HJ-125” of Cemedine Co., Ltd.). .

As the sample B, the additive-free silicone rubber 0.
145 g was produced in the same shape (30 × 5 × 1 mm ³ ).

Samples A and B were face-to-face bonded to each other to prepare a bipolymer. The produced bipolymer shape memory material was subjected to an initial activation operation for a hydrogen storage alloy in a sample in a reaction tube made of stainless steel (SUS316) in an atmosphere of ultra-high purity hydrogen 7N at a hydrogen pressure of about 50 bar. went. The activated sample was loaded into the container 41 of the measuring device 40, and after evacuation and hydrogenation were repeated alternately several times, the shape change of the sample at each introduced hydrogen pressure was measured by the video recorder 49.

As shown in FIG. 3, the change in shape of the sample is measured as shown in FIG. 3, where the horizontal length X and the vertical length of the sample are Y and the shape change ratio (Y / X) is used. I asked.

5A and 5B show the sample temperature 296.
It is a photograph which shows the mode of shape change at the time of evacuation of a sample at 15K and hydrogen introduction. The shape change of the bipolymer shape memory alloy after activation had a certain curvature such that the composite material was inside and the additive-free silicone rubber was outside during vacuum evacuation, as shown in FIG. 5 (a). Bent in shape. Then, when the pressure of the hydrogen gas introduced into the container 41 is gradually increased, the curvature of the sample gradually increases, and as shown in FIG. 5B, the sample is substantially linear at a pressure of about 2 bar. It was confirmed that the shape would be.

The mechanism by which the shape memory effect is exhibited in the above bipolymer material will be described with reference to FIG.

As shown in FIGS. 6 (a) and 6 (b), the side (B side) of the composite material 31 is contracted by removing hydrogen from the composite material 31 by evacuation, and the composite material 31 is inward. The sample 32 bends so that the additive-free silicone rubber 30 is on the outside.

On the other hand, as shown in (c) and (d) of FIG. 6, a hydride is formed in the composite material 31 by hydrogen absorption, and the composite material 31 side (B) is expanded by volume expansion.
Side) extends, the curvature of the sample 32 gradually increases, and finally it becomes a substantially linear shape.

In FIG. 10, the horizontal axis represents the absolute pressure P in the container 41.
FIG. 4 is a characteristic diagram showing the correlation between the hydrogen introduction pressure and the shape displacement of the LaNi ₅ alloy dispersed shape memory material at the time of hydrogen introduction, in which (bar) is taken and the shape displacement (Y / X) of the sample is plotted on the vertical axis. In the figure, the white square plots show the shape displacement at the time of vacuum evacuation, and the black circles show the shape displacement at each pressure 10 minutes after the introduction of hydrogen. As is apparent from this figure, as the applied hydrogen pressure rises, the shape displacement (Y / X) decreases, and in the region where the pressure P is about 3 bar or more, the sample has a curved shape and becomes almost a linear shape. I was able to confirm that.

In FIG. 11, the horizontal axis represents the time t (seconds) from the start of hydrogen introduction, and the vertical axis represents the shape displacement (Y / X) of the sample, showing the shape displacement at the time of introducing hydrogen at each sample temperature. It is a characteristic view which shows the examined result. In the figure, the square plot shows the results at a temperature of 296.34K, and the circle plot shows the results at a temperature of 3
The result of 03.15K, the triangular plot is 309.15K
The results are shown below. The hydrogen partial pressure P is 3.84b.
It was set to ar (constant). As is clear from this figure, it was confirmed that in the hydrogen storage alloy dispersed shape memory bipolymer, the amount of shape displacement increased as the hydrogen introduction time increased at each sample temperature.

In FIG. 12, the horizontal axis represents the reciprocal of temperature (1 / T) when the shape displacement (Y / X) of the hydrogen storage alloy dispersed shape memory material is 0.0018, and the vertical axis represents the introduction of hydrogen. It is a characteristic view showing the result of examining the correlation between the two by taking the reciprocal of the time from (1 / t). The apparent activation energy of the hydrogen storage alloy dispersed shape memory material was calculated from the slope of the straight line connecting the black circle plots in the figure, and Ea = 1
It was found to be 4.5 kcal / mol. This is almost in agreement with the activation energy for diffusion of hydrogen in the metal.

(Example 3) (LaNi-based hydrogen storage alloy shape memory composite material) Example 3
As a result, the LaNi ₅ alloy powder was fixed, and the shape memory effect exhibited when the alloy absorbs and releases hydrogen is investigated.

A method of manufacturing the sample of Example 3 will be described.

As sample A, LaNi ₅ alloy fine particles and silicone rubber were sufficiently kneaded to prepare a plate-like sample of 30 × 5 × 1 mm (length × width × thickness).

As sample B, additive-free silicone rubber 0.
145 g was made into substantially the same shape (30 × 5 × 1 mm ³ ).

Samples A and B were face-to-face bonded to each other to prepare a bipolymer. The produced bipolymer shape memory material was placed in a reaction tube made of stainless steel (SUS316) using a high pressure Giebelt apparatus in an atmosphere of ultra-high purity hydrogen (7N) at a hydrogen pressure of about 50 bar (a pressure of about 5 MPa). Initial activation was performed on the hydrogen storage alloy in the sample. The activated sample is loaded into the container 41 of the measuring device 40,
0.04 MPa, 0.08 MPa, 0.12 MPa,
The shape change of the sample under the applied hydrogen pressure of 0.16 MPa and 0.2 MPa and in the vacuum using the oil rotary pump was measured by the video recorder 49.

In FIG. 13, the horizontal axis represents the hydrogen partial pressure (MPa) of the gas supply system, and the vertical axis represents the shape displacement (Y / X) of the sample. The LaNi ₅ alloy shape memory composite material of Example 3 was obtained. It is a characteristic view which shows the correlation of the introduced hydrogen pressure and shape change about a sample. As is clear from this figure, as the applied hydrogen pressure increased, the sample changed from a shape having a curvature to a linear shape, and the shape of the sample changed with good reproducibility due to changes in the hydrogen partial pressure.

(Example 4) (LaNiCo-based hydrogen storage alloy shape memory composite material) Sample
As A, LaNi₃Co₂Hydrogen storage represented by alloys
0.684 g of gold powder (particle size: 25-40 μm) and silicon
Rubber (Product name "HJ-12 of Cemedine Co., Ltd.
5 ") Shape 30 in which 0.065 g was sufficiently kneaded and dispersed
× 5 × lmm ³Create a composite material (length x width x thickness)
It was

As the sample B, the additive-free silicone rubber 0.
172 g was produced in the same shape (30 × 5 × 1 mm ³ ).

Samples A and B were face-to-face bonded to each other to prepare a bipolymer. The produced bipolymer shape memory material was subjected to an initial activation operation for a hydrogen storage alloy in a sample in a reaction tube made of stainless steel (SUS316) in an atmosphere of ultra-high purity hydrogen 7N at a hydrogen pressure of about 50 bar. went. The activated sample was loaded into the container 41 of the measuring device 40, and after evacuation and hydrogenation were repeated alternately several times, the shape change of the sample at each introduced hydrogen pressure was measured by the video recorder 49.

The result of measuring the shape of the sample of Example 4 by the measuring device 40 will be described with reference to FIG. 14A and 14B are photographs showing the shape of the sample at the time of evacuation and the shape at the time of introducing hydrogen at a sample temperature of 37 to 38 ° C., respectively. As shown in FIG. 14A, the shape of the sample after evacuation is substantially linear.
On the other hand, from the start of hydrogen introduction at a hydrogen partial pressure of 2 bar,
After a lapse of seconds, as shown in FIG. 14 (B), the shape of the sample was changed and the sample was greatly bent toward the non-added silicone rubber. It can be explained that this shape change occurred because the LaNi _3.3 Co _2.1 alloy shape memory composite material exhibited volume expansion due to hydrogen absorption.

The mechanism by which the shape memory effect is exhibited in the above bipolymer material will be described with reference to FIG.

As shown in FIGS. 15A and 15B,
When hydrogen is removed from the composite material A by evacuation, the side of the composite material A contracts, the composite material A in this contracted state and the additive-free silicone rubber B are aligned in the same length, and the bipolymer material is substantially linear. It has a shape of a shape.

On the other hand, as shown in (c) and (d) of FIG. 15, hydride is formed in the composite material A by hydrogen storage, and volume expansion causes the composite material A side to expand,
As a result, the bipolymer material is bent and deformed with the composite material A on the outside and the additive-free silicone rubber B on the inside.

In FIG. 16, the horizontal axis represents the absolute pressure P in the container 41.
(Bar) is taken, and the shape displacement (Y / X) of the sample is plotted on the vertical axis. The results of examining the correlation between hydrogen pressure and shape displacement in the LaNi _3.3 Co _2.1 alloy shape memory composite material at the time of hydrogen introduction are shown. It is a characteristic diagram. In this case, the temperature of the sample was set to 36.5 ± 0.5 ° C. (309.65 ± 0.5K). In the figure, the open square plots show the shape displacement at the time of vacuum evacuation, and the black circle plots show the shape displacement of each hydrogen pressure 10 minutes after the start of hydrogen introduction.
As is clear from this figure, it was confirmed that the amount of shape displacement increased as the applied hydrogen pressure increased, and when the pressure reached about 2 bar or higher, the shape was changed from a linear shape by evacuation to a shape having a curvature.

Further, when the stress (σ _L ) was calculated from the total cross-sectional area of the sample as the deformation output when the shape memory effect was exhibited, it was 10.4 kPa. When the stress (σ _t ) was calculated from the cross-sectional area, it was confirmed that a force of 20.4 kPa was developed.

(Third Embodiment) (Medical Soft Catheter) Next, a medical soft catheter using the above composite material will be described with reference to FIG.

As shown in FIG. 7A, first, the semi-cylindrical first and second elements 31 and 30 are bonded to each other on the ventral side plane to produce a cylindrical element assembly 32A. The first and second elements 31 and 30 respectively have hollow portions 33 and 34 for allowing gas to flow therethrough.
The proximal ends of the first and second elements 31 and 30 are respectively connected to a gas supply source (not shown), and a mixed gas of hydrogen and nitrogen is supplied to the hollow portion 33 of the first element so that the catheter tip is Via the hollow portion 34 of the second element
A circulation circuit is formed through which the gas is returned to the original gas supply source. In the introduced gas, argon was added to adjust the hydrogen concentration. The mixing ratio of hydrogen and Ar is, for example, 5
To 95 (H ₂ : Ar = 5: 95).

As a result of investigating the H ₂ —N ₂ mixed gas, almost the same results as the H ₂ —Ar mixed gas are obtained.

By adjusting the hydrogen concentration in this way or by appropriately selecting the element assembly 32A for introducing hydrogen, the catheter tip can be displaced in the desired direction by the desired displacement amount.

The hydrogen storage alloy shape memory composite material described in the second embodiment was used for the first element 31, and the additive-free silicone rubber was used for the second element 30. A hollow wire rod was produced by a punching rolling method, and the hollow wire rod was extruded to be formed into a semi-cylindrical shape to obtain first and second elements 31 and 30.

As shown in FIG. 7 (b), four cylindrical element assemblies 32A are bundled and adhered to each other.
The medical soft catheter 36 is used. In this case, the first
The element 31 is disposed inside and the second element 30 is disposed outside. By thus integrating the plurality of element assemblies 32A, the catheter 36 can be moved in any direction. That is, by appropriately selecting from the four first elements 31 and supplying the hydrogen-containing gas, the first elements 31 extend,
The tip of the catheter 36 can be bent and deformed in a desired direction to be displaced. The entire catheter 36 may be covered with a polymer film having excellent biocompatibility in order to prevent harm to the human body.

Next, various characteristics of the hydrogen storage alloy shape memory material will be described with reference to FIGS. 17 to 26.

[0072] (temperature dependence) 17, the elapsed time from the hydrogen feed initiated the horizontal axis (in seconds), taking the strain variation Δε of sample (ppm) on the vertical axis, LaNi _3.3 Co _2.1 alloy shaped It is a characteristic view which shows the result of having investigated about the correlation of hydrogen introduction time and the amount of strain changes, changing the temperature of the sample which consists of memory composite materials variously. The square plot in the figure indicates the sample temperature of 28.
The results of 3 ± 1K and hydrogen pressure of 2.0 bar, the circle plots of sample temperature 311 ± 1K and hydrogen pressure of 1.9 bar, the triangular plots of sample temperature 329 ± 1K and hydrogen pressure of 1.9 bar, and vice versa. Triangle plot shows sample temperature 35
The results at 9 ± 1 K and hydrogen pressure of 2.0 bar are shown. As is clear from this figure, about 5
After 00 seconds, the temperature is 311 ± 1K and 329 ± 1
Deformation was observed in each of the K samples, and it was found that the amount of deformation of the sample increased with the passage of time.

In FIG. 18, the horizontal axis represents the sample temperature (K) and the vertical axis represents the strain change amount Δε (ppm) of the sample.
LaNi _{3.3 by} changing the elapsed time from the start of hydrogen introduction
It is a characteristic view which shows the correlation of the temperature and the amount of strain changes of the sample which consists of _Co2.1 alloy shape memory composite materials. The hydrogen pressure condition was measured as 1.95 ± 0.5 bar. In the figure, square plots show the results after 100 seconds from the hydrogen introduction, circle plots show the results after 300 seconds from the hydrogen introduction, triangular plots show the results after 1000 seconds from the hydrogen introduction, and inverse triangle plots. The results after 3000 seconds from the introduction of hydrogen are shown. As is clear from this figure, 34 ° C to 4 ° C
It was confirmed that the strain change amount Δε of the sample significantly increased in the temperature range of 0 ° C. That is, it was confirmed that the material of this example remarkably exhibits the shape memory effect in the temperature range of human body temperature (38 ± 1 ° C.). It was also confirmed that the material of this example had a maximum strain change amount Δε when the hydrogen introduction elapsed time was 3000 seconds.

(Pressure Dependence) In FIG. 19, the horizontal axis represents the hydrogen pressure P _H2 (bar), and the vertical axis represents the strain change amount Δε of the sample.
(Ppm) is a characteristic diagram showing the correlation between the applied hydrogen pressure and the strain change amount of the LaNi _3.3 Co _2.1 alloy shape memory composite material. Sample temperature 309.5 ± 0.5K (constant)
The strain change amount Δε of each sample was measured under the following conditions. In the figure, a square plot shows the strain change amount at the time of vacuum evacuation, and a black circle plot shows the strain change amount 10 minutes after the start of hydrogen introduction. As is clear from this figure, when the applied hydrogen pressure becomes about 1 bar, the strain change amount of the sample appears, and the strain change amount of the sample greatly changes in the hydrogen pressure range of 1 to 2 bar.
It was found that the strain change amount saturates and the change becomes smaller when the temperature rises above ar.

Thus, the temperature range of body temperature (36.5 ° C.,
At 309.5 K), a large strain change at a low hydrogen pressure of 1-2 bar indicates that when LaNi _3.3 Co _2.1 alloy shape memory composite material is applied to a medical catheter, it is substantially effective for the human body. This is one proof that it is harmless.

Such pressure dependence is also apparent from the characteristic diagram shown in FIG. 10 described above, and the material of the present invention exhibits a shape memory effect under the condition of low hydrogen pressure of about 1 to 3 bar. Express.

(Load Dependence) In FIG. 20, the introduced hydrogen pressure (P _H2 ) is plotted on the abscissa and the strain change amount (Δε) is plotted on the ordinate, and applied to the LaNi _3.3 Co _2.1 alloy shape memory composite material sample. FIG. 6 is a characteristic diagram showing a correlation between an introduced hydrogen pressure (P _H2 ) and a strain change amount (Δε) by changing load stress variously. The strain change amount Δε of each sample was measured 10 minutes after the start of hydrogen introduction under the condition that the sample temperature was 310.0 ± 0.5 K (constant), which is close to the body temperature. In the figure, square plots show strain change amounts when hydrogen pressure is 0.478 kPa, circle plots show strain change amounts when hydrogen pressure is 0.956 kPa, and triangular plots show strain change amounts when hydrogen pressure is 4.781 kPa. The rhombus plot shows hydrogen pressure of 9.561 kP
The amount of change in strain when a is shown. As is clear from this figure, it has been found that the strain change amount Δε increases as the introduced hydrogen pressure increases. On the other hand, it was confirmed that the maximum strain change amount Δεmax decreases as the load applied to the sample increases.

(Relationship between stress and maximum strain) In FIG. 21, the horizontal axis represents stress σ (kPa) and the vertical axis represents maximum strain Δεmax.
(Ppm) to obtain a hydrogen storage alloy shape memory material (composite material and thin film) as a general-purpose shape memory material Ni-T
It is a characteristic view which shows the correlation of stress (sigma) and maximum strain (DELTA) (epsilon) max, respectively compared with i alloy. Square plots in the figure are Ni
-The stress-strain characteristics of the Ti alloy, the white circle plots and the black circle plots show the stress-strain characteristics of the hydrogen storage alloy shape memory thin film, and the white triangle plots and the black triangle plots show the stress strain characteristics of the hydrogen storage alloy dispersed shape memory composite material. Are shown respectively.

The difference between the white circle plot and the black circle plot is
The former shows the stress σ _L obtained by dividing the load Lw by the total cross-sectional area A of the whole sample, while the latter divides the sum of the load and the weight of the sample (Lw + Ls) by the cross-sectional area At of the thin film portion. The stress σ _t is shown (equations (3) and (4) in FIG. 24).
reference). The difference between the white triangle plot and the black triangle plot is that the former shows the stress σ _L obtained by dividing the load load Lw by the total cross-sectional area A of the entire sample, whereas the latter shows the load load and the sample weight. Sum (Lw + Ls) is the cross-sectional area Ac of the composite material part
27 shows the stress σc divided by (see equations (7) and (8) in FIG. 26).

As is apparent from this figure, the hydrogen storage alloy dispersed shape memory composite material has a smaller force associated with deformation than the Ni-Ti alloy, but the maximum strain Δεmax shows a value close to that of the Ni-Ti alloy. It is expected that a large deformation due to the shape memory effect will be obtained. On the other hand, the hydrogen storage alloy shape memory thin film has a smaller amount of strain deformation than the Ni—Ti alloy, but the stress σ _{t of} only the thin film portion, which is the drive source, accompanying the strain change
Was confirmed to exceed that of the Ni-Ti alloy.

FIG. 22A shows a sample after vacuum evacuation (left side), a sample after hydrogen gas introduction (hydrogen pressure 3 bar) (center), and exposure to an atmosphere of diluted argon gas (Ar + 5% H ₂ ) for 5000 seconds. It is a photograph which shows a sample (right side) when doing. Further, in FIG. 22B, the horizontal axis represents the elapsed time (seconds) from the start of hydrogen introduction, and the vertical axis represents strain ε.
(Ppm) to obtain argon diluted hydrogen gas (Ar + 5
It is a characteristic view showing a strain change of a sample in a% H ₂ ) atmosphere. The sample temperature was 37.0 ± 1.0 ° C. (constant), and the argon diluted hydrogen gas (Ar + 5% H ₂ ) pressure was 1 bar. In the figure, the solid line drawn at the strain ε of about 7500 ppm corresponds to the strain (initial strain) after evacuation, and the white circle plot shows the argon diluted hydrogen gas (Ar + 5%).
The result of the strain measurement value of the sample at each time when H ₂ ) was kept flowing is shown. As is clear from this figure, by switching from hydrogen gas to argon-diluted hydrogen gas (Ar + 5% H ₂ ), a small curvature due to volume expansion due to hydride formation of the hydrogen storage alloy dispersed and fixed on the composite material side can be achieved. It was confirmed that the shape having a large curvature (center of FIG. 22A) returned to the shape having a large curvature (right side of FIG. 22A).

By switching and flowing the hydrogen gas and the argon-diluted hydrogen gas in this way, it becomes possible to deform the medical soft catheter in the third embodiment into a shape having a desired curvature. It will be very useful as a therapeutic catheter in the medical field.

FIG. 23 is a schematic diagram of a mathematical formula and a sample for explaining the strain (ε) measuring method of the hydrogen storage alloy shape memory thin film. The ρ, η, d _f , and d _s shown in the figure were measured, and the strains (0.2 μm) associated with hydrogen absorption of the thin film portion (0.2 μm) were measured using these measured values and equations (1) and (2). The Δε ^f ) value was calculated.

FIG. 24 is a schematic diagram of a mathematical formula and a sample for explaining the method of calculating the stress (σ) of the hydrogen storage alloy shape memory thin film. Lw shown in FIG., A, Ls, A _t was measured, these measurements and equation (3), (4) and the total cross-sectional area of the sample (11.2 .mu.m) using a thin film portion (0 .2μ
The values of σ _L , σ _t , and values associated with the hydrogen storage of m) were calculated.

FIG. 25 is a schematic diagram of mathematical expressions and samples for explaining the strain (ε) measuring method of the hydrogen storage alloy dispersed shape memory composite material. Ρ, η, d, r, ε ₀ shown in the figure are measured, and the strain (ε) value due to hydrogen storage in the composite material portion is calculated by using these measured values and equations (5) and (6). Was calculated.

FIG. 26 is a schematic diagram of mathematical expressions and samples for explaining the method for calculating the stress (σ) of the hydrogen storage alloy dispersed shape memory composite material. Lw, A, Ls, and Ac shown in the figure were measured, respectively, and using these measured values and equations (7) and (8), the total cross-sectional area of the sample and σ _L accompanying the hydrogen absorption of the composite material portion were measured. , Σc, and the value were calculated.

[0087]

EFFECTS OF THE INVENTION According to the present invention, a strong hydrogen storage alloy shape memory thin film capable of exerting a strong shape memory effect in the temperature range of human body temperature and being able to overcome the resistance of surrounding living tissues to be deformed. And a strong hydrogen storage alloy shape memory composite material can be provided.

Further, according to the present invention, there is provided a medical soft catheter which has good biocompatibility, has a soft property that is kind to the human body, and can exert a shape memory effect without applying heat. can do.

[Brief description of drawings]

FIG. 1 is an internal perspective sectional view showing an outline of a film forming apparatus (flash vapor deposition apparatus) used for manufacturing a strong hydrogen storage shape memory alloy thin film of the present invention.

FIG. 2 is a schematic configuration block diagram showing a hydrogen storage shape memory effect measuring device equipped with a glass reaction tube.

FIG. 3 is a schematic sectional view illustrating a method for measuring shape displacement (Y / X) when a sample exhibits a hydrogen storage shape memory effect.

4 (a) is a photograph showing the appearance of LaNi _6.5 alloy thin film sample before activation, (b) the LaNi _6.5 during evacuation
Photograph showing the appearance of the alloy thin film sample, (c) is a photograph showing the appearance of the LaNi _6.5 alloy thin film sample when hydrogen is introduced.

FIG. 5 (a) is a strong hydrogen storage alloy dispersed shape memory composite material of the present invention (LaNi having a shape having a curvature during evacuation).
₅ alloy fine particles / silicone rubber composite material) Photograph showing the appearance of the sample, (b) hydrogen introduction (hydrogen pressure of about 2 bar)
3 is a photograph showing the appearance of a sample of the strong hydrogen-absorbing alloy dispersed shape memory composite material of the present invention that has changed from a curvature shape to a linear shape by the above.

6A to 6D are schematic views for explaining the shape memory mechanism of the composite material of the present invention.

FIG. 7A is a perspective view schematically showing a soft catheter member using the strong hydrogen storage alloy dispersed shape memory composite material of the present invention, and FIG. 7B is a perspective view schematically showing a soft shape memory catheter.

FIG. 8 is a characteristic diagram showing the correlation between the elapsed time from the start of hydrogen introduction and the shape displacement (Y / X) at each sample temperature of the LaNi _6.5 thin film.

FIG. 9: Shape displacement of LaNi _6.5 alloy thin film sample (Y /
The characteristic view which shows the correlation of the reciprocal of temperature (1 / T) and the reciprocal of time (1 / t) when (X) becomes 0.007.

FIG. 10: Hydrogen storage alloy dispersed shape memory material (composite material)
FIG. 6 is a characteristic diagram showing the correlation between the hydrogen introduction pressure and the shape displacement (Y / X) of FIG.

FIG. 11: Hydrogen introduction time and shape displacement (Y) at each sample temperature of the strong hydrogen storage alloy-dispersed shape memory composite material of the present invention.
/ X) is a characteristic diagram showing a correlation with.

FIG. 12 shows the reciprocal of temperature (1 / T) and the reciprocal of time (1 / t) when the shape displacement (Y / X) of the strong hydrogen storage alloy dispersed shape memory composite material of the present invention becomes 0.0018. FIG.

FIG. 13 is a characteristic diagram showing the relationship between hydrogen pressure and shape displacement (Y / X).

FIG. 14 (A) is a photograph showing the appearance of a composite material sample having a LaNi _3.3 Co _2.1 powder-dispersed polymer (when hydrogen is released), and FIG. 14B is a composite material sample having a LaNi _3.3 Co _2.1 powder-dispersed polymer (hydrogen storage). A photograph showing the appearance of

15A to 15D are schematic views for explaining the shape memory mechanism of the alloy thin film and the composite material of the present invention, respectively.

FIG. 16 is a characteristic diagram showing the results of examining the hydrogen storage shape memory effect of a composite material having a LaNi _3.3 Co _2.1 alloy fine particle dispersed polymer.

FIG. 17 is a characteristic diagram showing a correlation between hydrogen introduction time and strain change amount at each sample temperature of the hydrogen storage alloy dispersed shape memory composite material.

FIG. 18 is a characteristic diagram showing the correlation between each sample temperature and the amount of strain change of the hydrogen storage alloy dispersed shape memory composite material.

FIG. 19 is a characteristic diagram showing a correlation between an applied hydrogen pressure and a strain change amount of a hydrogen storage alloy dispersed shape memory composite material.

FIG. 20 is a characteristic diagram showing a correlation between introduced hydrogen pressure (P _H2 ) and strain change amount (Δε) at each load stress.

FIG. 21 is a characteristic diagram showing the correlation between the stress σ and the maximum strain change amount Δεmax in the Ni—Ti alloy and the hydrogen storage alloy shape memory material (bipolymer).

FIG. 22 (a) is a sample after vacuum evacuation (left side), a sample after hydrogen gas introduction (center), and argon diluted hydrogen gas (Ar).
Photographs showing the sample (right side) when exposed to + 5% H ₂ ) atmosphere for 5000 seconds, (b) is a characteristic diagram showing the strain change of the sample in an argon diluted hydrogen gas (Ar + 5% H ₂ ) atmosphere.

FIG. 23 is a schematic diagram of a mathematical formula and a sample for explaining a strain (ε) measuring method of a hydrogen storage alloy shape memory thin film.

FIG. 24 is a schematic diagram of a mathematical formula and a sample for explaining a stress (σ) calculation method of a hydrogen storage alloy shape memory thin film.

FIG. 25 is a schematic diagram of a mathematical formula and a sample for explaining a strain (ε) measuring method of a hydrogen storage alloy dispersed shape memory composite material.

FIG. 26 is a schematic diagram of a mathematical formula and a sample for explaining a method for calculating a stress (σ) of a hydrogen storage alloy dispersed shape memory composite material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Film-forming apparatus (flash vapor deposition apparatus), 2 ... Vacuum container, 3 ... Exhaust path, 4 ... Flash heating unit, 5 ... Heater, 6 ... Raw material powder, 7, 11 ... Post, 8, 9 ...
Insulating member, 10 ... Hopper, 17 ... Guide post, 18 ... Elevating member, 19 ... Support plate, 20 ... Sample holding part, 21 ... Motor, 22 ... Drive shaft, 23 ... Holder, 24 ... Cover, 29 ... Substrate (sample ), 30 ... Polymer material (silicone rubber substrate), 31 ... Mixed material of shape memory alloy and polymer material (silicone rubber), 32 ... Composite sample, 32A ... Composite material, 33 ... Gas introduction channel, 34 ... Gas discharge flow path, 35 ... Partition, 36 ... Soft catheter, 40 ... Measuring device, 41 ... Heating container, 42 ... Lid, 43 ... Tube, 44a to 44c
... Valve, 45 ... Rotary pump, 46 ... Hydrogen gas cylinder, 47 ... Thermometer, 48 ... Pressure gauge, 49 ... Video camera.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiromasa Yabe             1117 Kitakaneme, Hiratsuka-shi, Kanagawa Tokai University             Graduate School of Engineering (72) Inventor Kim Byung-suk             1117 Kitakaneme, Hiratsuka-shi, Kanagawa Tokai University             Graduate School of Engineering F-term (reference) 4C081 AC08 CA271 CA272 CG04                       DC03                 4C167 AA01 BB02 BB07 BB37 BB51                       CC04 EE03 FF01 GG02 GG03                       GG23 GG26 GG32 GG42 HH30

Claims (19)

[Claims] 1. A strong hydrogen storage characterized by comprising a LaNix-based alloy obtained by laminating on a substrate using any one of a physical vapor phase method, a chemical vapor phase method and a physicochemical vapor phase method. Alloy shape memory thin film. 2. The thin film according to claim 1, wherein the stoichiometric coefficient x is in the range of 4 to 7. 3. The thin film according to claim 1, which is made of a LaNi ₅ alloy. 4. The thin film according to claim 1, which is made of LaNi _6.5 alloy. 5. The thin film according to claim 1, further comprising a LaNixCoy alloy containing Co. 6. The stoichiometric coefficient x is in the range of 3 to 4, and the stoichiometric coefficient y is in the range of 1.5 to 2.5. Thin film. 7. The thin film according to claim 5, which is made of a LaNi _3.3 Co _2.1 alloy. 8. The thin film according to claim 1, wherein the film thickness is 1 μm or less. 9. A strong hydrogen storage alloy shape memory composite material, characterized in that fine particles of LaNix alloy are dispersed in a polymer material to form a composite. 10. The fine particles of the alloy have an average particle size of 1 to
The composite material according to claim 9, wherein the composite material comprises fine particles in the range of 40 μm. 11. The composite material according to claim 9, wherein the polymer material is made of silicone rubber. 12. The composite material according to claim 9, wherein the fine particles of the alloy have a stoichiometric coefficient x in the range of 4 to 7. 13. The composite material according to claim 9, wherein the fine particles of the alloy are made of LaNi ₅ alloy. 14. The composite material according to claim 9, wherein the fine particles of the alloy are made of LaNi _6.5 alloy. 15. The composite material according to claim 9, wherein the fine particles of the alloy are made of LaNixCoy alloy further containing Co. 16. The fine particles of the alloy have a stoichiometric coefficient x in the range of 3 to 4 and a stoichiometric coefficient y in the range of 1.5 to 2.5. Claim 1
5. The composite material according to item 5. 17. The fine particles of the alloy are LaNi _3.3 C.
o Composite material according to claim 15, characterized in that it consists of a _2.1 alloy. 18. A first element made of the composite material according to any one of claims 9 to 17 having a hollow portion through which hydrogen gas or hydrogen-containing gas flows, and A second element having a hollow portion through which the hydrogen gas or the hydrogen-containing gas that has flowed through the hollow portion of the first element flows and which is made of a polymer material and is bonded to the first element; A medical soft catheter characterized by the following. 19. The first and second elements are formed in a semi-cylindrical shape, and the ventral planes of the semi-cylindrical first and second elements are bonded to form a cylindrical element assembly. 20. The catheter according to claim 19, wherein a plurality of assemblies are bundled.