KR20140090422A - A method for manufacturing shape memory nano-filament and a shape memory nano-filament manufactured thereby - Google Patents

Abstract

The present invention relates to a method for manufacturing a shape memory nano-filament and a shape memory nano-filament. Provided is a method for manufacturing the shape memory nano-filament comprising: a first process manufacturing a nanofiber having shape memory properties using a polymer; a second process manufacturing a thread formed of a nanofiber with a nanofiber by twisting the nanofiber; and a third process covering the thread formed of a nanofiber with a protector, so as to manufacture a shape memory nano-filament capable of intactly using as a medical material or a clothes material.

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing a shape memory nanofilament,

The present invention relates to a method of manufacturing a shape memory nanofilament and a shape memory nanofilament.

Conventionally, a structure having shape memory property is widely known. The shape memory property can be a predetermined shape inherent to the structure and a temporary shape that is different from the predetermined shape, and even after the structure is fixed in a temporary shape, It is a property that automatically returns to the shape. As a structure having shape memory property, a material having shape memory property in a material constituting a structure such as shape memory alloy or shape memory polymer is known and widely used.

However, at present, in the technical field of a structure having a shape memory property, it is strongly desired to produce a structure having various shapes or structures in order to further expand applicable fields. Among them, it is particularly demanded to produce fibrous structures promising as medical materials and clothing materials.

As such, conventionally, nanofibers made of a shape memory polymer and having shape memory property and a manufacturing method thereof are known (see Non-Patent Documents 1 and 2, for example). Nanofibers refer to fibers having an average diameter of several thousand nanometers or less and are recently attracting attention due to their specific properties (for example, large specific surface area) due to their thin thicknesses.

According to the nanofiber composed of the shape memory polymer as described above, it becomes possible to use a material that combines the properties of the shape memory polymer and the properties of the nanofiber.

Haitao Zhuo et al., &Quot; Materials Let ters, " 2008, 62, 14, p. Haitao Zhuo et al., &Quot; Journal of Materials Science ", 2011, Vol. 46, No.10, p.3464-3469

 However, there are two problems with conventional nanofibers made of shape memory polymers.

The first problem is that it is difficult to secure sufficient shape memory property of the nanofibers themselves or the " nonwoven fabric made of nanofibers ", and it is difficult to shorten the time for returning to a predetermined shape from a temporary shape in particular.

The second problem is that it is difficult to use the nanofiber state as a medical material or a garment material, mainly due to a problem of strength.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above problems, and it is an object of the present invention to provide a shape memory nanofilament capable of securing a sufficient shape memory property and capable of producing a shape memory nanofilament which can be used as a medical material or a garment material. And a method for producing the same. It is another object of the present invention to provide a shape memory nanofilament that can be produced by the above-described production method, can secure sufficient shape memory, and can be used as a medical material or a garment material as it is.

The inventors of the present invention have conducted intensive studies in order to solve the above problems. As a result, it has been found that the strength can be improved by making the nanofibers twisted to produce " To solve the second problem. Further, as shown in Experimental Examples to be described later, it is found that it is possible to shorten the time for returning the nanofiber to a predetermined shape by increasing the shape memory of the nanofiber by twisting the nanofiber, I have come to a solution. The present invention has the following features and effects.

[1] A method of manufacturing a shape memory nanofilament according to the present invention comprises: a first step of producing a nanofiber having shape memory by using a polymer; a step of twisting the nanofiber so that the nanofiber , And a third step of covering the " yarn made of nanofiber " with a protective material in this order.

According to the shape memory nanofilament manufacturing method of the present invention, since the second step of manufacturing the " yarn made of nanofibers " with the nanofibers being twisted together is included, the shape memory property of the nanofibers can be improved by twisting the nanofibers It is possible to manufacture a shape memory nanofilament which can increase the strength of the shape memory and secure sufficient shape memory.

Further, according to the shape memory nanofilament manufacturing method of the present invention, the nanofibers can be twisted into a "yarn made of nanofibers" because of the above-described second step, so that the strength can be improved. As a result, It is possible to manufacture shape memory nanofilaments that can be used as they are as clothing materials.

Therefore, according to the shape memory nanofilament manufacturing method of the present invention, shape memory nanofilaments which can secure sufficient shape memory and can be used as medical materials and clothes materials can be produced.

Further, according to the shape memory nanofilament manufacturing method of the present invention, since the third step of covering the " yarn made of nanofiber " with a protective material is included, the polymer constituting the nanofiber can be protected from heat and moisture .

Further, according to the shape memory nanofilament manufacturing method of the present invention, the "nanofiber thread" in which nanofibers having a large specific surface area are twisted is used as a base material, so that the specific surface area can be increased.

As the protective material used in the third step, it is preferable to use a curing agent which can be cured in a liquid state by electromagnetic waves or the like. By such a method, it is possible to carry out the third step relatively easily by curing after immersion in the " nanofiber yarn " in a liquid state.

Further, as the protective material, it is more preferable to use those having flexibility and elasticity even after curing. By such a method, it is possible to increase the elasticity of the shape memory nanofilaments and make them easy to use.

According to the shape memory nanofilament of the present invention, various kinds of sensors (temperature sensor, humidity sensor, etc.), medical materials (smart medical), biomaterials, medical materials (gibbs, Catheters, etc.), industrial materials (screws, binding materials, cushioning materials, insulating materials, etc.).

The shape memory nanofilament is a yarn-like structure made of a material (hereinafter referred to as " nanofiber yarn ") obtained by further adding nanofibers having shape memory properties, and has shape memory.

[2] In the method for producing a shape memory nanofilament according to the present invention, in the first step, the nanofiber is made to be a nonwoven fabric by an electrospinning method, and in the second step, the nonwoven fabric is twisted, It is preferable to produce a " yarn made of fibers ".

The field emission method is a method for obtaining nanofibers of relatively high quality (particularly, small diameter deviation) in a relatively simple manner, so that it is possible to manufacture high quality shape memory nanofilaments by a simple method as described above.

Further, by the above-described method, it becomes possible to manufacture shape memory nanofilaments without the labor of separating the " nonwoven fabric made of nanofibers "

[3] In the method for producing a shape memory nanofilament according to the present invention, the polymer preferably contains poly-epsilon -caprolactone as a main component.

By such a method, the shape memory nanofilaments as a whole can be made to have a shape memory property by utilizing the interaction between the phenomenon (softening at the melting point temperature and the expression of the shape memory effect) attributable to the properties of the polymer and the shape- Lt; / RTI >

[4] In the method for producing a shape memory nanofilament according to the present invention, the polymer preferably contains poly-L-lactic acid as a main component.

By using such a method, the shape memory nanofilaments as a whole have shape memory property by utilizing the interaction between the phenomenon (softening at the glass transition temperature and the expression of shape memory) attributable to the properties of the polymer and the shape stabilizing effect by the protective material .

[5] In the method of manufacturing a shape memory nanofilament according to the present invention, the protective member is preferably made of silicone rubber.

Since the silicone rubber can be cured in a liquid state by a curing agent and has flexibility and elasticity even after being cured, the third step can be carried out comparatively easily by this method, and the elasticity of the shape memory nanofilament So that it becomes easy to use.

In the above case, the third step of coating the surface of the " yarn made of nanofibers " with the protective material is performed by applying the liquid silicone rubber to the surface of the " yarn made of nanofiber " Immobilization)

[6] The shape memory nanofilament according to the present invention comprises a nanofiber yarn consisting of a polymer and having a shape memory property, and a protective material covering the " yarn made of nanofiber " .

According to the shape memory nanofilament of the present invention, since it is provided with the protective material covering the "yarn made of nanofiber" and the "yarn made of nanofiber" formed by twisting nanofibers having shape memory properties and made of polymer, Can be produced by the shape memory nanofilament manufacturing method of the present invention, can secure sufficient shape memory, and can be used as a medical material or a garment material as it is.

[7] In the shape memory nanofilament according to the present invention, the polymer preferably contains poly-epsilon -caprolactone as a main component.

With such a constitution, by utilizing the interaction between the development (softening at the melting point temperature and the manifestation of shape memory) due to the properties of the polymer and the shape stabilizing effect by the protective material, the shape memory nanofilaments Lt; / RTI >

[8] In the shape memory nanofilament according to the present invention, the polymer preferably comprises poly-L-lactic acid as a main component.

By employing such a constitution, the shape memory nanofilaments as a whole have shape memory property by utilizing the interaction between the phenomenon (softening at the glass transition temperature and the expression of shape memory) attributable to the properties of the polymer and the shape stabilizing effect by the protective material .

[9] In the shape memory nanofilament according to the present invention, the protective member is preferably made of silicone rubber.

 Since the silicone rubber can be cured in a liquid state by a curing agent and has flexibility and elasticity even after being cured, it is possible to manufacture the silicone rubber comparatively easily by such a constitution, and the shape memory nanofilament with high elasticity and easy to use .

According to the shape memory nanofilament manufacturing method of the present invention having the above configuration, since it includes the second step of manufacturing the " yarn made of nanofibers " with the nanofibers being twisted together with the nanofibers, It is possible to manufacture shape memory nanofilaments capable of increasing the shape memory property of the shape memory nanoparticles and ensuring sufficient shape memory.

Further, according to the shape memory nanofilament manufacturing method of the present invention, the nanofibers can be twisted into a "yarn made of nanofibers" because of the above-described second step, so that the strength can be improved. As a result, It is possible to produce shape memory nanofilaments that can be used as they are as a clothing material, and it is possible to manufacture shape memory nanofilaments which can secure sufficient shape memory and can be used as medical materials and clothing materials as they are .

Further, according to the shape memory nanofilament manufacturing method of the present invention, since the third step of covering the " yarn made of nanofiber " with a protective material is included, the polymer constituting the nanofiber can be protected from heat and moisture And the "nanofiber thread" in which nanofibers having a large specific surface area are twisted is used as a base material, so that the specific surface area can be increased.

In addition, the use of the interaction between the phenomenon (softening at the glass transition temperature and the expression of shape memory) attributable to the properties of the polymer and the shape stabilizing effect by the protective material enables the shape memory nanofilaments to have shape retention as a whole The silicone rubber can be cured in a liquid state by a curing agent and has flexibility and elasticity even after curing. Thus, the silicone rubber can be produced relatively easily by such a constitution, and the shape memory It becomes possible to make the nano filament.

Fig. 1 is a view for explaining the first step of the embodiment. Fig.
Fig. 2 is a view for explaining the second step of the embodiment. Fig.
Fig. 3 is a view for explaining the third step of the embodiment and the shape memory nanofilament 28. Fig.
4 is an electron micrograph of the shape memory nanofilament 28a according to Experimental Example 1. FIG.
Fig. 5 is a photograph showing the shape memory property of the shape memory nanofilament 28a according to Experimental Example 1. Fig.
6 is an electron micrograph of the shape memory nanofilament 28b according to Experimental Example 2. FIG.
Fig. 7 is a photograph showing the shape memory property of the shape memory nanofilament 28b according to Experimental Example 2. Fig.
Fig. 8 is a graph showing the difference in strength between the "nonwoven fabric made of nanofibers", "the yarn made of nanofibers" and shape memory nanofilaments.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a shape memory nanofilament and a shape memory nanofilament according to the present invention will be described based on embodiments shown in the drawings.

[Embodiment Mode]

Fig. 1 is a view for explaining the first step of the embodiment. Fig. 1 (a) is a view showing a state in which a sheet-like nonwoven fabric 22 made of nanofibers 21 is produced by an electrospinning method. FIG. 1 (b) Like nonwoven fabric 24 as shown in Fig.

Fig. 2 is a view for explaining the second step of the embodiment. Fig. In addition, the band-like nonwoven fabric 24 is twisted to form a "yarn made of nanofibers" 26 by the belt-like nonwoven fabric 24.

Fig. 3 is a view for explaining the third step of the embodiment and the shape memory nanofilament 28. Fig. 3 (a) is a view showing a "thread made of nanofibers" 26, and FIG. 3 (b) is a view showing a state in which a liquid 40 serving as a protective material is applied FIG. 3 (c) is a view showing the shape memory nanofibers 28 produced. FIG.

First, a method for producing shape memory nanofibers according to the embodiment will be described.

A method of manufacturing a shape memory nanofiber according to an embodiment includes a first step of producing a nanofiber using a polymer, a second step of producing a " nanofiber yarn " with the nanofiber twisted with the nanofiber, And a third step of covering the " yarn made of nanofiber " with a protective material in this order. Hereinafter, these steps will be described in order.

1. First step

The first step is a step of producing the nanofiber 21 having shape memory by using a polymer. The first step is to produce the nanofibers 21 so as to be the sheet-like nonwoven fabric 22 by the electric field irradiation method and thereafter cut the sheet-like nonwoven fabric 22 to obtain the belt-like nonwoven fabric 24 .

First, the sheet-like nonwoven fabric 22 is produced as follows. 1 (a), the polymer solution 20 to be a raw material of the nanofibers 21 is filled in the raw material tank 12 provided in the electric field radiation device 10, and the valve 13 To open the nozzle 14 so that the polymer solution 20 can be supplied. Subsequently, a high voltage is applied between the nozzle 14 and the collector 18 by using the high voltage power source 16 to cause the nanofibers 21 to be electroluminescent and to generate between the nozzle 14 and the collector 18 The nonwoven fabric sheet 22 made of the nanofibers 21 is produced by depositing the nanofibers 21 on the collector 18 by an electric field that is the same as that of the nanofibers 21. [

The thickness of the sheet-like nonwoven fabric 22 is, for example, 5 mu m to 50 mu m. The average diameter of the nanofibers 21 is, for example, 300 nm to 800 nm.

As the polymer used as the raw material of the nanofiber 21, those containing poly-epsilon -caprolactone (PCL) as a main component or poly-L-lactic acid (PLA or PLLA) as a main component can be suitably used. If the polymer is composed mainly of poly-epsilon -caprolactone, shape memory nanofilaments (Tm-modified nanofilaments) can be produced using the melting point of the polymer. Further, if the polymer comprises poly-L-lactic acid as a main component, shape memory nanofilaments (Tg modification type nanofilaments) can be produced using the glass transition point of the polymer.

 The voltage applied between the nozzle 14 and the collector 18 when manufacturing the sheet-like nonwoven fabric 22 using the field emission device 10 is determined by the distance between the nozzle 14 and the collector 18, But it is several kV to several tens kV. An optimum value may be selected depending on the kind of the polymer or the structure of the electric field radiation device 10. [

Subsequently, a strip-shaped nonwoven fabric 24 is produced. That is, as shown in Fig. 1 (b), the sheet-like nonwoven fabric 22 is cut to a width of about 1 mm to 100 mm to produce a band-like nonwoven fabric 24 which can be twisted.

2. Second Step

The second step is a step of producing a " yarn made of nanofibers " 26 by twisting the nanofibers with the nanofibers. Further, the second step is a step of twisting the belt-like nonwoven fabric 24 to produce the " yarn made of nanofiber " 26 with the belt-like nonwoven fabric 24.

In the second step, as shown in Fig. 2, the belt-like nonwoven fabric 24 produced in the first step is twisted using the twisted yarn device 30 to thereby produce the " yarn made of nanofiber 26 " . The strip-shaped nonwoven fabric 24 is twisted once by the main twist apparatus 32 and thereafter the yarn is twisted from the left side to the right side of Fig. 2 by using the yarn transfer devices 34 and 36, The " yarn made of nanofibers " 26 can be continuously produced.

When the yarn is fed using the yarn feeders 34 and 36 and the yarn feeding speed of the yarn feeding device 36 is higher than the yarn feeding speed of the yarn feeding device 34, 26 may be stretched.

The diameter of the " yarn made of nanofiber " 26 produced in the second step is, for example, 10 mu m to 1000 mu m. When the thickness is smaller than 10 탆, it may be difficult to secure a sufficient tensile strength. When the thickness is larger than 1000 탆, it is difficult to sufficiently ensure the uniformity of the surface of the "yarn made of nanofibers" There is. As long as the above problem can be solved, "yarn made of nanofiber" which is thinner than 10 μm or "yarn made of nanofiber" which is thicker than 1000 μm can be used as long as the effect and object of the present invention are not impaired.

3. The third process

As shown in Fig. 3, the third step is a step of manufacturing the shape memory nanofilaments 28 by covering the "yarn made of nanofibers" 26 with a protective material. In the third step, the protective material is made of silicone rubber. In the third step, the liquid silicone rubber obtained by mixing the curing agent is applied to the surface of the " yarn made of nanofibers " (see Fig. 3 (a)) (see Fig. (See Fig. 3 (c)).

Next, the shape memory nanofilament 28 according to the embodiment will be described

3, the shape memory nano filament 28 is composed of a "nanofiber thread" 26 made of a polymer and having twisted nanofibers 21 having a shape memory property, And a protective material 42 for covering the " thread "

As the polymer, those containing poly-epsilon -caprolactone or poly-L-lactic acid as a main component can be suitably used. If the polymer is composed of poly-epsilon -caprolactone as a main component, the shape memory nanofilament using the melting point of the polymer (Tm-modified nano filament) is obtained. Further, if the polymer comprises poly-L-lactic acid as a main component, shape memory nanofilaments (Tg modification type nanofilaments) can be produced using the glass transition point of the polymer.

The protection material 42 is made of silicone rubber.

Next, a method of manufacturing a shape memory nanofilament according to an embodiment and an effect of a shape memory nanofilament will be described.

The shape memory nanofilament manufacturing method according to the embodiment includes the second step of manufacturing the " yarn made of nanofiber " 26 by twisting the nanofibers 21 to form the nanofiber 21, It is possible to manufacture shape memory nanofilaments which can twist to increase the shape memory property of the nanofibers and ensure sufficient shape memory.

Further, according to the shape memory nanofilament manufacturing method according to the embodiment, since the above-mentioned second step is included, the nanofibers can be twisted into a "yarn made of nanofibers" to improve the strength. As a result, It is possible to manufacture shape memory nanofilaments which can be used as raw materials or as clothing materials.

Therefore, the shape memory nanofilament manufacturing method according to the embodiment makes it possible to manufacture shape memory nanofilaments which can secure sufficient shape memory and can be used as a medical material or a garment material as it is.

Further, according to the shape memory nanofilament manufacturing method according to the embodiment, since the third step of covering the " yarn made of nanofiber " 26 with the protective material 42 is included, It becomes possible to protect it from moisture.

Further, according to the shape memory nanofilament manufacturing method according to the embodiment, since the "nanofiber made of thread" 26, which is formed by twisting the nanofibers 21 having a large specific surface area, is used as the substrate, it is possible to increase the specific surface area It becomes.

Further, according to the shape memory nanofilament manufacturing method according to the embodiment, since the protective material 42 that can be cured in the liquid state by the curing agent is used, the protective material 42 is allowed to penetrate into the "yarn made of nanofiber" It is possible to perform the third step relatively easily by curing.

Further, according to the shape memory nanofilament manufacturing method according to the embodiment, since the material (silicone rubber) having flexibility and elasticity even after curing is used as the protection material 42, the elasticity of the shape memory nanofilament can be increased, Lt; / RTI >

Further, according to the shape memory nanofilament manufacturing method of the embodiment, since the nonwoven fabric made of the nanofibers 21 is produced by the field radiation method in the first step, it is possible to manufacture the shape memory nanofilament of high quality in a relatively simple manner It becomes possible.

Further, according to the shape memory nanofilament manufacturing method according to the embodiment, the " yarn made of nanofiber " 26 is produced by twisting the nonwoven fabric in the nonwoven fabric in the second step, It is possible to manufacture the shape memory nanofilaments without the labor of separating the shape memory nanofilaments.

Further, according to the method for producing a shape memory nanofilament according to the embodiment, since the polymer comprises poly-e-caprolactone as the main component or poly-L-lactic acid as the main component, the phenomenon caused by the properties of the polymer The shape memory nanofilaments as a whole can have shape memory property by utilizing the interaction of the shape memory effect (softening at a melting point temperature or softening at a glass transition temperature and expression of shape memory) and shape stabilizing effect by a protective material.

 Further, according to the shape memory nanofilament manufacturing method according to the embodiment, since the protective material 42 is made of silicone rubber, it is possible to carry out the third step relatively easily, and the elasticity of the shape memory nanofilament can be increased It becomes possible to make it easy to do.

 According to the shape memory nanofilament according to the embodiment, the protective material 42 covering the "yarn made of nanofibers" 26 and the "yarn made of nanofibers" 26, which twist the nanofibers 21 made of polymer, It can be manufactured by the shape memory nano filament manufacturing method according to the embodiment, and it is possible to secure sufficient shape memory, and it can be used as a medical material or a garment material as it is.

According to the shape memory nanofilament according to the embodiment, the polymer contains poly-.epsilon.-caprolactone as a main component or poly-L-lactic acid as a main component, so that the development due to the properties of the polymer Or softening at a glass transition temperature and the expression of shape memory) and the shape stabilizing effect by the protective material can be used to make shape memory nanofilaments have shape memory as a whole.

According to the shape memory nano filament according to the embodiment, since the protective material 42 is made of silicone rubber, the shape memory nanofilament can be manufactured relatively easily, and the shape memory nanofilament having high elasticity and easy to use can be obtained.

[Experimental Example 1]

4 is an electron micrograph of the shape memory nanofilament 28a according to Experimental Example 1. FIG. Each of the photographs of FIGS. 4 (a) and 4 (b) differs in magnification and place.

Fig. 5 is a photograph showing the shape memory property of the shape memory nanofilament 28a according to Experimental Example 1. Fig. 5A is a photograph of the shape memory nanofilament 28a having a predetermined shape and FIG. 5B is a photograph of the shape memory nanofilament 28a fixed in a temporary shape. FIG. c) is a photograph of the shape memory nanofilaments 28a returned to a predetermined shape.

In the following Experimental Example 1, the shape memory nanofilaments 28a were actually manufactured by the shape memory nanofilament manufacturing method according to the embodiment, and their properties were examined. In the following description, the description of the process part using the same method as the embodiment is omitted.

The shape memory nanofilaments 28a refer to shape memory nanofilaments produced by using the following poly-L-lactic acid as a raw material.

1. Manufacturing of shape memory nanofilaments 28a

In Experimental Example 1, shape memory nanofilaments 28a were produced by the method described in Embodiment 1.

Poly-L-lactic acid (manufactured by Aldrich, molecular weight: 152,000) was used as a raw material polymer.

In the first step, a solution of dichloromethane (DCM) / dimethylformamide (DMF) (DCM: DMF = 7: 3) containing poly-L-lactic acid at a concentration of 7.5 wt% was prepared as a polymer solution.

 When the sheet-like nonwoven fabric 22a (not shown) is manufactured by using the electric field radiation device 10a (having the same structure as that of the field emission device 10 of the embodiment, not shown), the nozzle 14a (Not shown) and the collector 18a (not shown) is 13 kV. The distance between the nozzle 14a and the collector 18a was set to 15 cm. The inner diameter of the nozzle 14a is 0.6 mm and the plastic syringe 12a (not shown) of 5 ml is attached to the nozzle 14a (needle). The polymer solution is injected at a rate of 2 ml / .

The thickness of the sheet-like nonwoven fabric 22a was set to be 5 mu m to 50 mu m.

The diameter of the nanofibers 21a (not shown) was 500 nm to 580 nm.

As the belt-like nonwoven fabric 24a (not shown), the length of the long side was 15 cm and the length of the short side was 5 mm.

In the second step, the band-like nonwoven fabric 24a produced in the first step was twisted to produce a " yarn made of nanofiber " 26a (not shown). The twist number of the " yarn made of nanofiber " 26a was set at 700 T / m (Twist per meter).

The diameter of the " yarn made of nanofiber " 26a produced in the second step was about 420 mu m.

3. The third process

In the third step, the "yarn made of nanofibers" 26a was covered with a protective material 42a (not shown) to produce shape memory nanofilaments. In the third step, "Silicone Guard 184 (made by Dow Corning)" which is silicone rubber was used as the protective material 42a. As a curing agent for curing the protective material, a curing agent attached to "Silicide 184" was mixed with silicone rubber at a ratio of 10: 1.

First, the liquid-phase " seal guard 184 " is applied to and impregnated into " thread made of nanofiber " 26a. Thereafter, the extra "seal guard 184" was removed from the surface of the "nanofiber seal" 26a by vacuum filtration and the "seal guard 184" was cured to form the protective material 42a . The shape memory nanofilaments 28a were prepared by drying at room temperature for 24 hours at a curing temperature of 60 deg. C and a curing time of 48 hours.

Thereafter, the produced shape memory nanofilaments 28a were subjected to heat treatment to confirm that they were in a predetermined shape (see Fig. 5 (a)). The heat treatment was carried out at 70 ° C to 75 ° C for 48 hours. In the case of the shape memory nanofilaments 28a, the predetermined shape has a coil shape (spring shape) as shown in Fig. 5 (a).

As shown in Fig. 4, the shape memory nanofilaments 28a thus produced were observed by a scanning electron microscope (SEM) to confirm that the shape memory nanofilaments 28a were produced .

The shape memory nano filament 28a was subjected to a shape memory test. Further, the shape memory nanofilaments 28a thus produced became shape memory nanofilaments triggered by the glass transition point of poly-L-lactic acid.

It was confirmed that the shape memory nanofilaments 28a having a coil shape (predetermined shape) could be stretched while being heated and then cooled to be fixed in a substantially linear temporary shape (see Fig. 5 (b)).

It was also confirmed that the shape memory nanofilaments 28a were returned to a coil shape (predetermined shape) by heating the shape memory nanofilaments 28a fixed in a temporary shape and then cooling them (see (c ) Reference).

Further, the heating was performed at about 80 ° C, and the cooling was performed at room temperature.

It was confirmed that the time for returning to the predetermined shape from the temporary shape was about 1.8 seconds, and the shape memory nanofilaments 28a had a high shape memory property.

As described above, the shape memory property of the shape memory nanofilaments 28a made of poly-L-lactic acid as a raw material was confirmed.

[Experimental Example 2]

6 is an electron micrograph of the shape memory nanofilament 28b according to Experimental Example 2. FIG. 6A and 6B each have different magnifications and locations.

Fig. 7 is a photograph showing the shape memory property of the shape memory nanofilament 28b according to Experimental Example 2. Fig. Fig. 7A is a photograph of the shape memory nanofilament 28b having a predetermined shape, Fig. 7B is a photograph of shape memory nanofilament 28b fixed in a temporary shape, and Fig. c) is a photograph of the shape memory nanofilament 28b returned to a predetermined shape.

In the following Experimental Example 2, the shape memory nanofilaments 28b were actually manufactured by the shape memory nanofilament manufacturing method according to the embodiment, and their properties were investigated. In the following description, the description of the process part using the same method as the embodiment is omitted.

The shape memory nanofilaments 28b are shape memory nanofilaments made of poly-epsilon -caprolactone as a raw material as shown below.

1. Manufacturing of shape memory nanofilament 28b

In Experimental Example 1, shape memory nanofilaments 28b were produced by the method described in Embodiment 1.

As the polymer used as a raw material, poly-epsilon -caprolactone (manufactured by Aldrich, molecular weight: 70000 to 90000) was used.

Dimethylformamide (DMF) / ethanol (EtOH) (TCM: DMF: EtOH = 8: 1: 1) containing poly-epsilon -caprolactone at a concentration of 15 wt% 1) solution was prepared.

When the sheet-like nonwoven fabric 22b (not shown) is manufactured by using the electric field radiation device 10b (which is basically the same as the electric field radiation device 10 of the embodiment, not shown), the nozzle 14b ) And the collector 18b was set to 10 kV. The distance between the nozzle 14b and the collector 18b was set to 10 cm. The inside diameter of the nozzle 14b was 0.6 mm, and a plastic syringe 5 ml was attached to the nozzle 14b (needle), and the polymer solution was adjusted so as to come out from the nozzle at a rate of 2 ml / h.

The thickness of the sheet-like nonwoven fabric 22b was set to be 5 탆 to 50 탆.

The diameters of the nanofibers 21b (not shown) were 800 nm to 900 nm.

As the belt-like nonwoven fabric 24b (not shown), the length of the long side was 15 cm and the length of the short side (width) was 7 mm.

In the second step, the band-shaped nonwoven fabric produced in the first step was twisted to produce a " yarn made of nanofiber " 26b. The twist number of the " yarn made of nanofiber " 26b was set at 300 T / m.

The diameter of the " yarn made of nanofiber " 26b produced in the second step was about 500 mu m.

3. The third process

In the third step, the shape memory nanofilaments 28b were produced by covering the "yarn made of nanofibers" 26b with a protective material 42b (not shown). In the third step, "Silicone Guard 184 (made by Dow Corning)" which is silicone rubber was used as the protective material 42b. As a curing agent for curing the protective material, a curing agent attached to "Silicide 184" was mixed with silicone rubber at a ratio of 10: 1.

First, the liquid sealant 184 is applied and impregnated to the thread made of nanofibers 26b. Thereafter, the extra "thread guard 184" was removed from the surface of the "thread made of nanofiber" 26b by vacuum filtration, and the "thread guard 184" was cured to form the protective material 42b . The shape memory nanofilament 28b was prepared by drying at room temperature for 24 hours at a curing temperature of 60 deg. C and a curing time of 48 hours.

Thereafter, the produced shape memory nanofilaments 28b were subjected to heat treatment to confirm that they were in a predetermined shape (see Fig. 7 (a)). The heat treatment was carried out at 70 ° C to 75 ° C for 48 hours. In the case of the shape memory nanofilament 28b, as shown in Fig. 7 (a), the predetermined shape has a coil shape (spring shape).

As shown in Fig. 6, the shape memory nanofilaments 28b thus produced were observed by a scanning electron microscope (SEM) to confirm that the shape memory nanofilaments 28b were produced .

Further, the shape memory nano filament 28b was subjected to a shape memory test. Further, the shape memory nanofilaments 28b thus produced became shape memory nanofilaments triggered by the melting point of poly-epsilon -caprolactone.

It was confirmed that the shape memory nanofilaments 28b having a coil shape (predetermined shape) could be stretched while being heated and then cooled to be fixed in a substantially linear temporal shape (see Fig. 7 (b)).

It was confirmed that the shape memory nano filament 28b fixed in a temporary shape was heated and then cooled to return the shape memory nano filament 28b to a coil shape (predetermined shape) (Fig. 7 (c) Reference).

Further, the heating was made to be about 80 DEG C, and the cooling was performed at room temperature. It was confirmed that the time taken to return from the temporary shape to the predetermined shape was about 1.75 seconds and that the shape memory nanofilaments 28a had a high shape memory property.

As described above, the shape memory property of the shape memory nanofilament 28b made of poly-epsilon -caprolactone as a raw material was confirmed.

[Experimental Example 3]

Fig. 8 is a graph showing the difference in strength between the "nonwoven fabric made of nanofibers", "the yarn made of nanofibers" and shape memory nanofilaments. Fig. 8 (a) is a graph showing the tensile strength, and Fig. 8 (b) is a table showing the difference in strength. In the graph of FIG. 8A, the vertical axis represents the stress MPa, the horizontal axis represents the elongation (%), and the tilting of the end of the graph indicates that the object is broken at that point. In the graph of Fig. 8 (a), the symbol "a" is a graph for a " nonwoven fabric made of nanofibers "Quot; c "is a graph of a " thread made of heat treated nanofibers ", and the symbol" d " And a shape memory nanofilament (shape memory nanofilament 28a).

In Experimental Example 3, an experiment was conducted to confirm that the strength (tensile strength) was improved by changing the "nonwoven fabric made of nanofibers" (band-like nonwoven fabric) into "yarn made of nanofibers". Experiments were conducted to confirm the difference in strength due to the presence or absence of the protective material.

In Experimental Example 3, the belt-like nonwoven fabric 24a of Experimental Example 1 was used as the " nonwoven fabric made of nanofiber ", and the " yarn made of nanofiber " 26a of Experimental Example 1 was used as " And shape memory nanofilaments 28a were used as shape memory nanofilaments. Further, a " yarn made of heat treated nanofiber " having the same constitution as shape memory nanofilament 28a was prepared except that no protective material was provided for comparison.

For the measurement of tensile strength of "yarn made of nanofiber", "yarn made of heat-treated nanofiber" and shape memory nanofilament, Autograph "AG-5000G" of Seishin Shimazu Co., Ltd. was used . As a measurement condition, the head speed was 5 mm / min and the temperature was room temperature. In order to measure the tensile strength of the "nonwoven fabric made of nanofibers", Tensilon RTC 1250-A, a universal material testing machine manufactured by A & D Co., Ltd. was used. As a measurement condition, a test member (dumbbell type) having a length of 165 mm, a width of 19 mm, and a thickness of 3 mm was used based on the provisions of ASTM D-638. The maximum load capacity was 50N.

First, as shown in Fig. 8, regarding the strength of the "nonwoven fabric made of nanofibers" (band-like nonwoven fabric) and the "yarn made of nanofibers", a "nonwoven fabric made of nanofibers" , It was confirmed that the tensile strength of 2 times or more as compared with the state of the nonwoven fabric was obtained, and the strength was improved (see (a) and (b) in FIG. 8).

Subsequently, it was confirmed that the difference in strength due to the presence or absence of the protective material improves the strength when the protective material is present (see (c) and (d) in FIG. 8).

Further, when comparing the "shape made of nanofibers" with the shape memory nanofilaments, the shape memory nanofilaments have a smaller tensile strength at break than a "thread made of nanofibers" but a larger tensile strength (about 1.4 times) I could confirm that I could.

Although the present invention has been described based on the above embodiment, the present invention is not limited to the above embodiment. The present invention can be carried out in various forms without departing from the spirit of the invention. For example, the following modifications are possible.

(1) The number, material, and shape of each constituent element described in the above embodiment are illustrative, and can be changed within a range that does not impair the effect of the present invention.

(2) In the above embodiment, the "yarn made of nanofiber" 26 is produced by the belt-like nonwoven fabric 24, but the present invention is not limited to this. For example, a " yarn made of nanofiber " may be produced with a sheet-like nonwoven fabric, or a yarn made of " nanofiber "

10: Field emission device
12: raw material tank
13: Valve
14: Nozzle
16: High voltage power source
18: collector
20: polymer solution
21: Nano fiber
22: sheet nonwoven fabric
24: Band-like nonwoven fabric
26: "yarn made of nanofiber"
28, 28a, 28b: shape memory nanofilaments
30: Twisted device
32: Main twist device
34, 36: yarn feeder
40: Liquid to be protective material
42: Protection material

Claims (9)

A first step of producing a nanofiber having shape memory by using a polymer,
A second step of twisting the nanofibers to produce a " yarn made of nanofibers " with the nanofibers, and
And a third step of covering the " yarn made of nanofibers " with a protective material in this order. The method according to claim 1,
In the first step, the nanofibers are produced to be a nonwoven fabric by an electrospinning method.
And a step of twisting the nonwoven fabric in the second step to produce a " yarn made of nanofibers " with the nonwoven fabric. 3. The method according to claim 1 or 2,
Wherein the polymer comprises poly-epsilon -caprolactone as a main component. 3. The method according to claim 1 or 2,
Wherein the polymer comprises poly-L-lactic acid as a main component. The method according to claim 1,
Wherein the protective material is made of silicone rubber. A shape memory nanofilament comprising a polymer and comprising a "yarn made of nanofibers" in which nanofibers having shape memory are twisted and a protective material covering said "yarn made of nanofibers". The method according to claim 6,
Wherein the polymer comprises poly-epsilon -caprolactone as a main component. The method according to claim 6,
Wherein the polymer comprises poly-L-lactic acid as a main component. 9. The method according to any one of claims 6 to 8,
Wherein the protective material is made of silicone rubber.

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