JP2013031595A - Tubular body and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tubular body capable of being quickly manufactured and a method for manufacturing the same because conventional artificial blood vessels, various kinds of which are developed, are difficult to manufacture and because the conventional artificial blood vessel cannot be used for a thin blood vessel due to the poor flexibility.SOLUTION: The tubular body includes: a nonwoven fabric layer made of ultrafine fibers whose diameter is 10 μm or smaller formed by an electrospinning method as the innermost layer; and a cover material present outside the layer. The nonwoven fabric layer and the cover material are fixed to each other. When the outer diameter of a mandrel whose outer diameter is variable is large, a film is wound around the mandrel, and the nonwoven fabric layer of the ultrafine fibers whose diameter is 10 μm or smaller is formed by the electrospinning method on the surface of the film. Next, the cover material to cover the whole surface of the nonwoven fabric layer is fixed, and after that, the mandrel is put into a state with a smaller outer diameter thereafter and the film is removed. Finally, the tubular body composed of the nonwoven fabric layer and the cover material is removed from the mandrel.

Description

  The present invention relates to a cylindrical body and a method for manufacturing the same.

  The cylindrical body is a pipe or tube, and an artificial blood vessel will be described below as an example, but the present invention is not limited to this.

Recently, various vascular diseases (such as arteriosclerosis) have increased, and the demand for artificial blood vessels has increased due to improved surgical methods. That is, a damaged blood vessel is replaced with an artificial blood vessel, or is reinforced and treated with an artificial blood vessel.
This artificial blood vessel is required not only to leak not only blood cells but also plasma, but also to have various functions of blood vessels. For example, durability, adaptability to the human body, safety, and the like. Furthermore, since it is introduced by surgery, it must be easy to anastomosis.

Various conventional artificial blood vessels have been developed and used. For example, the artificial blood vessel described in Patent Document 1 has a tubular artificial blood vessel main body, a first reinforcing body provided on the outer periphery thereof, and a second reinforcing body on the outer peripheral surface thereof.
JP2009-022511

  This conventional one seems to have a great effect on blood leakage, but it is difficult to manufacture and has poor flexibility and cannot be used for thin blood vessels.

  Further, in the case of an artificial blood vessel, a member that does not allow liquid to pass through at all, that is, a member that has no space, does not proliferate endothelial cells, and blood leaks if a large hole is formed. Although the pores are vacant, it is better to immediately block the cellular components around the pores, causing clogging.

  Therefore, the present invention provides a cylindrical body that can satisfy the above-described demand for an artificial blood vessel as much as possible and can be manufactured quickly, and a method for manufacturing the same.

In view of such a current situation, the present inventors have completed the cylindrical body of the present invention and the manufacturing method thereof as a result of intensive studies. The feature of the cylindrical body is that the electrospinning method is used for the cylindrical body. In the production method, the formed nonwoven fabric layer of ultrafine fibers having a diameter of 10 μm or less is the innermost layer, at least the cover material is present on the outer side, and the nonwoven fabric layer and the cover material are fixed. Is a non-woven fabric layer of ultrafine fibers having a diameter of 10 μm or less by electrospinning on the surface of the film body when the outer diameter of the mandrel is variable and the mandrel has a large outer diameter. Next, the cover material covering the entire surface of the nonwoven fabric layer is fixed, and then the mandrel is brought into a state having a small outer diameter, and the cylindrical body composed of the nonwoven fabric layer and the cover material is removed from the mandrel, and finally The film body is removed.

First, the cylindrical body of the present invention will be described.
The cylindrical body here is not limited to the artificial blood vessel described above, but also a cylindrical filter that traps fine particles, and other applications. Although the size is not limited, the outer diameter is particularly preferably about 3 mm to 40 mm, and more preferably 5 mm to 25 mm.

In the electrospinning method, a polymer is dissolved, a voltage is applied to the polymer, and fine fibers are blown toward a grounded member at a remote position, and the fiber is laminated on the member or another intermediate member. .
As an example, there is a method in which a polymer is put into a syringe, extruded from a narrow hole provided at the tip, the solvent is evaporated to form a fiber, and it is sprayed randomly on a target object. At this time, the syringe is charged, the target object is grounded, and the ultrafine fibers are easy to fly. The thickness of the fiber can be adjusted by the diameter of the hole at the tip and the concentration in the solvent.

There is also a type in which a container in which a polymer is dissolved in a solvent is placed below, and the same object as above is placed above it. is there.

  Thus, a non-woven fabric made of ultrafine fibers is formed on the base material (film body, mandrel, etc.). The thickness of the fiber is preferably several tens of nm to 10 μm, and more preferably several hundreds of nm to 10 μm. This polymer (fiber) may be any one that dissolves in a solvent.

The ultrafine fiber layer means that the ultrafine fibers are not simply fixed to several base materials, but are formed into a film having a large number of through-holes by a large number of ultrafine fibers. The thickness of this film is arbitrary, and conversely, by adjusting the thickness, the size of the penetration can be limited. An example of the thickness is preferably several tens of μm to several hundreds of μm.
Moreover, although the size of the pores (voids) formed by these fibers is arbitrary, several tens of μm to several hundreds of μm are preferable.

The fiber used in this electrospinning method may be one using a plurality of types of polymers. It is desirable that the plurality of components have different melting points. Although the degree of difference is not limited, in practice, it is preferable that there is a difference of 30 ° C. or more.
As will be described later, this melts and does not melt when the whole is heated.

Considering the ease of temperature management and the like, it is more preferable if there is a difference of about 50 to 100 ° C. In the case of three or more components, there is no need for all differences. There should be at least one difference.

  The melting point in the present application is not only the melting point in the sense that the crystal melts, but also the softening point of the amorphous material, and if it becomes higher than the softening point, it can be fixed to other things and keep its state if it falls below that temperature. It also includes the meaning of temperature that can be used.

  Any solvent may be used as long as it dissolves the polymer or the like. The concentration in the solvent also varies depending on the viscosity of the polymer, the thickness of the fiber to be produced, the solvent used, etc., but is usually about 1 to 50% by weight.

Examples of such fibers are as follows when a combination of two kinds of polymers and oligomers and a solvent at that time are exemplified. The last is a solvent.
1 Polylactic acid Polycaprolactone Dichloromethane 2 Polylactic acid Polybutylene succinate Dichloromethane 3 Polyacrylonitrile Polylactic acid N, N-dimethylformamide 4 Polyamide Polymethyl methacrylate Formic acid 5 Polyamide Polyoxymethylene Hexafluoroisopropanol 6 Polyamide Polyethylene terephthalate Hexafluoroisopropanol 7 Polyethylene oxide Polycarbonate Chloroform 8 Polyaniline Polystyrene Chloroform 9 Polyurethane Polylactic acid N, N-dimethylformamide 10 Polystyrene Polyvinyl chloride Chloroform 11 Polycaprolactone Polymethyl methacrylate Chloroform 12 Polycarbonate Polycarbonate oligomer Chloroform

  In the above example, a plurality of polymers are dissolved in the same manner and solidified as one fiber, but this is a method using a plurality of fibers composed of different components. This is like a non-woven fabric or the like in which polylactic acid fibers and polycaprolactone fibers are separately present.

  The cylindrical body of the present invention is characterized in that the nonwoven fabric layer of the ultrafine fibers is in the innermost layer, and in the conventional artificial blood vessel, the innermost side is a net of metal or a reinforcing material of woven fabric. Since the nonwoven fabric layer of ultrafine fibers exists in the innermost layer, it is particularly good for artificial blood vessels.

A cover material here means a braid, a knitted fabric, and a woven fabric. That is, these cover materials are fixed around the above-described nonwoven fabric to reinforce the nonwoven fabric. Even when the tubular body bends, it can bend and follow without breaking, and has sufficient strength.

  The nonwoven fabric layer and the cover material are fixed, but the fixing method includes adhesion and fusion. Adhesion is separately used for the adhesion, and both or one of the objects to be fused is fused and fixed. The fixing method described later can be used.

  This completes the structure of the cylindrical body of the present invention, but it may be covered with another material on the outside of the cover material.

  Next, the manufacturing method of the present invention will be described. This is one manufacturing method of the above-described tubular body of the present invention and is a very convenient method. Hereinafter, the words of claim 2 will be described in order.

A mandrel serves as a mandrel when manufacturing a cylindrical body, and its cross section is usually circular. However, in the case of the present invention, strictly speaking, it does not have to be a circle.
The mandrel's outer diameter can be changed includes those in which the outer diameter of the mandrel itself changes, and those in which the mandrel itself does not change, but additionally, a spacer is attached to and detached from the mandrel to change the total outer diameter.
The mandrel is usually made of metal and is used as one of the electrodes of the electrospinning method. However, the mandrel may not be made of metal and may be placed behind the mandrel.

What changes the outer diameter of the mandrel itself is one in which the mandrel is divided, one in which a thin plate (film) is wound (such as a spring), and the like. The outer diameter is changed by moving the divided parts closer or further away.
In the case of winding, the outer diameter is changed depending on whether the winding is advanced or rewinded. Of course, it is not limited to these.

The attachment / detachment method of the spacer is performed by the difference in outer diameter between the state where the spacer is attached to the mandrel and the state where the spacer is removed.
The spacer is preferably a string, plastic or metal rod.

The film body is a thin film such as a film or paper.
In particular, a fluorine film such as Teflon (registered trademark) or a silicon film having high peelability, or a paper having high heat resistance coated with a fluorine resin or a silicon resin is preferable.

Further, it is preferable that the film body is not simply wound around a large rectangular shape, but a thin width body is wound around a mandrel spirally. If it does in this way, when the whole will be extracted from the mandrel after manufacture, a film body will exist in a spiral inside what became a cylinder. When the film body and the nonwoven fabric described later are peeled off, it is only necessary to peel the film body on the inside sequentially in a spiral manner, and there is no need to pull out against the friction.
When it is not spiral, the film body is pulled out against the friction, and the nonwoven fabric may be damaged.

After the non-woven fabric is formed on the mandrel surface, the cover material is continuously formed around the cover material. That is, in the case of braids, there are a plurality of string feeding portions (simple bobbins) that can rotate around the mandrel, and may be known ones.
Also for knitting. It may be the same as that of knitting a tubular body such as socks.
The same applies to the woven fabric, as long as it can be woven in a cylindrical shape around the mandrel.

The cover material and the non-woven fabric are fixed so as not to come off.
The fixing method includes adhesion and fusion. Adhesion is separately used for the adhesion, and both or one of the objects to be fused is fused and fixed.

  In the case of the bonding method, after forming the nonwoven fabric, before forming the cover material thereon, an adhesive is applied to the surface of the nonwoven fabric. The adhesive may be a solvent type, an emulsion type, or a hot melt type.

  In the case of the fusing method, the temperature is raised to a temperature (approximately 10 to 50 ° C.) slightly higher than the temperature of the lower melting point of either the cover material or the nonwoven fabric, and is melted and fixed. The melted material is either the cover material or the nonwoven fabric, and particularly the melted material of the cover material, but both may be melted.

Further, when the nonwoven fabric uses a plurality of types of fibers having different melting points and the lowest melting point is lower than the melting point of the cover material, the temperature may be higher than the one melting point. On the contrary, the same applies to the case where the cover material uses a plurality of types of fibers, and the cover material may be at a higher temperature than that having the lowest melting point of the cover material.

Furthermore, the melting point of the cover material and the nonwoven fabric may be the same. In that case, the fusion may be performed at a higher temperature.

As an example of the degree of temperature rise, in the case of a nonwoven fabric composed of two kinds of fibers, polylactic acid (melting point: about 160 ° C.) and polycaprolactone (melting point: about 60 ° C.), the temperature is 60 ° C. or higher (for example, about 100 ° C.). ) Is heated. By this heating, a part (or all) of the low melting point fiber melts and adheres to other fibers and the cover material.

The heating method may be any method as long as the fiber is heated, such as heating with an electric heater or sending hot air to the fiber.
Of course, heat fusion and adhesion may be combined.

  In order to easily and reliably fix the nonwoven fabric and the cover material, the cover material may be fixed and then pressed with a roller or the like (a large number of rollers are provided on the upper part of the mandrel).

In the production method of the present invention, the steps described in claim 2 are essential, but steps before or after this method may be added without departing from the spirit of the present invention. For example, another film body is wound after the method of the present invention, or something is wound on a mandrel before the present invention is implemented.

  Examples of the use of the cylindrical body of the present invention include artificial organs (artificial blood vessels) and various separation membranes. Although it is a cylindrical body, it may be cut and used as a film.

The present invention has the following advantages.
(1) The cylindrical body of the present invention is optimal as an artificial blood vessel because the nonwoven fabric layer of ultrafine fibers is present on the innermost side.
(2) Since a nonwoven fabric composed of very thin fibers is reinforced with a fiber cover material, a strong and flexible material can be manufactured.
(3) Since the outer diameter of the mandrel is changed, it is easy to remove it from the mandrel. Conventional mandrel usage is difficult to remove from the mandrel and often damages the product.
(4) Since the film body is used, it is easier to remove from the mandrel, and this film body is also easy to remove from the nonwoven fabric.
(5) The size of the particles passing through the fiber layer can be freely adjusted depending on the thickness and amount of the nonwoven fabric and the ultrafine fibers.

It is a schematic side view which shows the mandrel 1 used for manufacture of this invention cylindrical body. It is a side view which shows the place which wound the paper which coated the silicon resin in the state of FIG. 1 in the spiral. It is a side view which shows the place which has formed the nonwoven fabric layer by the electrospinning method. It is a side view which shows the place which forms the braid on the surface. 6 is a cross-sectional view showing another example of the mandrel 1. FIG. It is a fragmentary perspective view which shows one example of this invention cylindrical body.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

  FIG. 1 is a schematic side view showing a mandrel 1 used for manufacturing the cylindrical body of the present invention. A silicon resin plastic rod (diameter 2 mm) 2 is placed along a mandrel (outer diameter 10 mm) 1. FIG. 2 shows a state in which paper 3 (width 10 mm, thickness 100 μm) coated with silicon resin is wound in a spiral in this state.

FIG. 3 shows a state in which a nonwoven fabric layer 4 is formed by electrospinning on the film body (paper) 3 wound around. Here, the fiber constituting the nonwoven fabric is nylon. The thickness of the nonwoven fabric is approximately 0.5 mm.
A container 5 is filled with a solution obtained by dissolving a polymer in a solvent. The container is energized and the metal mandrel 1 above it is grounded. From the container 5, the liquid rises upward, and a large number of liquids fly toward the mandrel 1. The solvent volatilizes in the middle of the liquid and adheres to the mandrel 1 in a fibrous form. And it is laminated like a nonwoven fabric. At this time, the mandrel is rotated regularly or irregularly so that the entire circumference is laminated as uniformly as possible.

  FIG. 4 shows a braid 7 formed on the surface of the state shown in FIG. Although not shown in the figure, there are many bobbins for feeding out the respective strings 8 below, which are revolving and rotating. Such devices are already commercially available. This is a so-called automatic braid manufacturing apparatus.

  After this step, hot air is blown from the surroundings, and a part of the cover material is melted and fixed to the nonwoven fabric. For fixing, a plurality of rollers (not shown) are provided on the upper part of the mandrel 1 and pressed. Finally, this is removed from the mandrel 1 and the film body 3 existing inside is sequentially peeled off in a spiral. If the film body is removed, it is completed.

FIG. 5 shows another example of the mandrel 1, which can be divided into two in the longitudinal direction, each or one of which can be moved, and the outer diameter can be changed. Two members may be connected by a hinge and movable.

FIG. 6 is a partial perspective view showing an example of the cylindrical body of the present invention. This is an example in which the nonwoven fabric 4 is present on the inner side and the reinforcing braid 7 is present on the outer side. Ideal for artificial blood vessels.

1 Mandrel 2 Spacer 3 Film body 4 Non-woven fabric 5 Container 6 Ground 7 Braid 8 String

Claims (2)

A nonwoven fabric layer of ultrafine fibers having a diameter of 10 μm or less formed by an electrospinning method is the innermost layer, and at least a cover material is present on the outer side, and the nonwoven fabric layer and the cover material are fixed to each other. Tubular body. When a mandrel having a variable outer diameter has a large outer diameter, a film body is wound around the mandrel, and a non-woven fabric layer of ultrafine fibers having a diameter of 10 μm or less is formed on the surface of the film body by an electrospinning method. A cover material covering the entire surface of the non-woven fabric layer is fixed, and then the mandrel is brought into a state having a small outer diameter, a cylindrical body composed of the non-woven fabric layer and the cover material is removed from the mandrel, and finally the film body is removed. A method for producing a cylindrical body characterized by comprising:

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