JPH01314563A - Preparation of artificial blood vessel - Google Patents

Abstract

PURPOSE:To prepare an artificial blood vessel excellent in extensibility and flexibility by inserting a cylindrical or columnar straight pipe, which has an inner diameter near to that of a fiber cylindrical article, in the fiber cylindrical article prior to the heating corrugation setting process of said article and processing the fiber cylindrical article into a round tubular shape at specific temp. CONSTITUTION:A fiber cylindrical article is pref. formed by using two or more kinds of yarns composed of a polyester fiber and also using a fiber having monofilament fineness of 1.0 denier or less at least in a part thereof. The cylindrical or columnar straight pipe to be inserted in the fiber cylindrical article is desirably composed of stainless steel, plastic or iron and the diameter thereof is appropriately selected so as to be matched with the inner diameter of an artificial blood vessel or the diameter of a core rod having corrugation. Since the melting effect of the fiber or the setting effect of corrugation performed next becomes weak if heating temp. processing a round tubular shape is too high and the tubular shape is not held if said heating temp. is low, the heating temp. is set to a range lower at least by 10 deg.C than corrugation setting temp. but holding temp. capable of imparting a shape, that is, 100-160 deg.C and a treatment time is desirably 1-30min. After the round tubular shape is processed, the whole is cooled to pull off the straight pipe. Next, the core rod having a corrugated grove is inserted in the fiber cylindrical article to be pressed thereto and heated to perform corrugation setting processing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing an artificial blood vessel with excellent extensibility and flexibility.

[Prior Art] Crimping has been particularly important in the production of artificial blood vessels. Without crimping, the tube material becomes flat and difficult to handle. Furthermore, due to problems such as occlusion even when transplanted, crimping is widely used to satisfy extensibility, flexibility, and rigidity.

Generally, the method of crimping tube material is to insert a molded object with corrugated grooves into the tube material, and heat-treat the tube material by sequentially pressing it against the corrugated groove along the corrugated groove. , has been subjected to crimp processing.

However, even if you try to insert a molded object with corrugated grooves into a tube material of approximately the same size, the tube material may be bent, wrinkled, twisted, etc. It starts to get caught on the tip,
This will result in a very slippery situation. For this reason, if the tube material is forcibly inserted and pressed against a molded object with corrugated grooves, there will be areas where the tube material slips or areas where it does not slide, and the crimp shape becomes deeper or shallower, resulting in the so-called The crimp shape becomes non-uniform and distortion occurs. Moreover, as a result, there are parts of the tube material in a tense state and parts in a relaxed state, which results in uneven density of the fibers, which causes variations in the pores 9a and causes bleeding. On the other hand, if a tube material that is thicker than the shaped article having the corrugated grooves is inserted, wrinkles will occur when it is pressed against the corrugated grooves, and the crimp shape will be non-uniform.

Various studies are underway to improve these problems. For example, in Japanese Patent Application Laid-Open No. 52-70597Q, the tube material is pressed into an annular corrugated groove, subjected to a first heat treatment, cooled, placed on a cylindrical mandrel, pressed from one side to shorten the tube material, and then heated again. Treated, cooled and crimp formed.

However, the method of shortening the tube material by pushing it from one side after placing it on a cylindrical mandrel has problems such as difficulty in uniform shortening in the longitudinal direction, resulting in irregularities, and strong crimping, resulting in a hard product texture. occurs.

In addition, using a shrink tube, the tube material is heated and pressed with a corrugated object in a sand inch method, and after cooling,
There are methods such as arranging it on a cylindrical mandrel, shortening it, heating it and cooling it again to form a crimp, but this method is expensive and the process is complicated, so it cannot be easily done on a large scale production basis. .

[Problem to be Solved by the Invention 1] Artificial blood vessels made of knitted fabrics are subjected to various crimping processes to prevent them from deforming during implantation and from causing occlusion after surgery, as described above, but the tube material and Since the crimp shape is poor with the molded article having the wavy grooves, the crimp shape becomes non-uniform and distortion occurs.

In addition, in order to obtain a strong crimp, the process becomes complicated and costs increase, and the texture of the product becomes hard, making it difficult to pass a sewing needle through it when it is connected to a biological blood vessel.

The present inventors have diligently studied the above-mentioned problem, which is a fatal defect in artificial blood vessels, and have arrived at the present invention.

[Means to solve the problem] The present invention has the following configuration.

When inserting a mandrel having a spiral or annular wave groove into the M male part and heating it to set the corrugation, the inner diameter of the fiber cylindrical object must be A method for producing an artificial blood vessel, which comprises inserting a nearly cylindrical or cylindrical straight tube and processing the shape into a circular tube at a temperature that is at least 10° C. lower than the waveform setting processing temperature, but at which the shape can be imparted.

In the present invention, fiber N cylindrical objects include woven fabrics, knitted fabrics, braided cords,
Any material such as non-woven material 15 may be used, and any material may be selected regardless of the type of structure.

Furthermore, the fibers may be of one type or may be a mixture of two or more types of fibers. Also, although it is acceptable to use one type of thread during the formation of the basic structure, it is more preferable to use two or more types of thread. For non-woven fabrics, common card) f/C, flash spinning, melt blowing method, air injection method (OF)
It is preferable to do so.

Further, the polymer used as the fiber may be of any type, such as polyester, polyamide, polytetrafluoroethylene, polyolefin, etc., but polyester is particularly preferred. When using multi-component fibers, the final polymer remaining is the above-mentioned polymer, but other combined components include polystyrene, polyethylene, water-soluble polyamide, alkaline aqueous solution-soluble polyester, water-soluble polyvinyl alcohol, etc., as appropriate. It is possible.

In order to make the present invention more effective, I
It is preferable to use ultrafine fibers having a single fiber fineness of 1.0 denier or less as at least some of the i-fibers of N.

By using ultrafine fibers, the three-dimensional entangling effect is enhanced and the artificial blood vessel becomes extremely flexible.

Regarding the above-mentioned ultra-fine fibers, fibers that are already in the form of ultra-fine fibers may be used as they are for serum formation, but duplexes may be formed using fibers that can be made ultra-fine by chemical or physical means. , and then ultrafine to form a tube of ultrafine fibers. Ultrafine fibers can be obtained by using ordinary spinning methods with due care; however, as in the case of polyester, undrawn fibers are drawn under specific conditions. It is also possible to use thin fibers.

On the other hand, examples of fibers that can be made ultra-fine by post-processing include Japanese Patent Publications No. 48-22126 and Japanese Patent Publication No. 53-22593.
It refers to a type of fiber that is fibrillated or made extremely fine by removing one component of a multicomponent fiber, or by peeling and piffing it, as seen in Tan Publication.

Next, in the method for manufacturing an artificial blood vessel according to the present invention, the cylindrical or cylindrical straight tube to be fitted into the fiber tube is a rod or tube made of stainless steel, plastic, iron, glass, rubber, ceramics, etc. It is desirable to use

The diameter may be appropriately selected depending on the inner diameter of the artificial blood vessel and the diameter of the corrugated mandrel. Similarly, the mandrel with corrugated grooves may be made of stainless steel, plastic, iron, glass, rubber, ceramics, etc., or may be used in combination of two or more types. It is also desirable to use a material that can withstand high temperatures.

A cylindrical or cylindrical straight tube is inserted into a fibrous tube and subjected to heat treatment to shape it into a circular tube. If the heating temperature is too high, the effect of melting the fibers and the next corrugated pit will be weakened, and if the heating temperature is too low, the shape cannot be maintained.
At least 10℃ higher than the waveform setting processing temperature to be performed later
A temperature that is low but can give shape, specifically 100~
A range of 160°C is desirable.

Regarding the processing time, after the cylindrical or cylindrical straight pipe is removed from the fibrous cylindrical object, the fibrous cylindrical object must maintain its cylindrical shape, so the processing time is 1 to 30 minutes.
Time is preferable.

The II cylindrical object before inserting the cylindrical or cylindrical straight pipe is washed with water and dried in a hot air dryer, etc., and the fibrous cylindrical object is bent, twisted, wrinkled, etc. If you insert a mandrel with a corrugated groove as it is, it will cause distortion in the fiber tube because it will not slide easily. Processing without turbulence is required.

The important pre-processing for limp processing of the present invention is to perform processing to maintain the shape before setting the waveform. It was thought that by processing the cylindrical fiber material into a circular shape, the fiber cylindrical material would become hard and would not be able to be crimped uniformly, but surprisingly, the sliding condition with the mandrel with the corrugated groove was smooth. It became something.

In other words, because the cylindrical fibrous material is regularly pressed against the concave and convex portions of the mandrel having corrugated grooves while maintaining its cylindrical shape, uneven density of the fibers of the fibrous cylindrical material is reduced. There is no longer any misalignment of eyes. In addition, it is difficult to insert a mandrel with a corrugated groove into a fibrous cylindrical object that has bends or wrinkles without causing distortion.
It is possible to insert a cylindrical or cylindrical straight pipe without causing distortion.

After shaping into a cylindrical shape, it is cooled to below the glass transition point and a cylindrical or cylindrical straight tube is centrally cut out.

Next, a mandrel having a corrugated groove is inserted while the cylindrical fiber M maintains its cylindrical shape.

The waveform of the mandrel with waveform grooves is spiral or annular, and the shape of the waveform grooves is triangular, trapezoidal, or sinusoidal, and the tip is rounded rather than pointed. It is preferable that it is.

This method of pressing a fibrous cylindrical object onto a mandrel having wavy grooves involves successively pressing the cylindrical cylindrical cylindrical object along the pitch of the wavy grooves. Since the cylindrical shape is processed, the fibrous tubular material is easy to slip and can be pressed regularly and evenly into the concave and convex portions of the mandrel of the corrugated groove. In addition, since the fibers are processed into a cylindrical shape, even when pressed against a mandrel having corrugated grooves, the cylindrical fibers remain fixed, making it difficult for the fibers to become uneven in density. Therefore, a regular limp shape with uniform fiber density can be obtained.

The pressing method may be achieved by pressing with a mandrel having a wave-shaped groove and a circular tube-shaped object having the same wave-shaped grooves on the inside, or by tightening with a ring-shaped object. It is also possible to use wire, monofilament, twisted yarn, braided cord, or the like to wrap and press the core along the grooves of the mandrel having the corrugated grooves.

By these methods, a cylindrical fiber material is heated while being pressed against a mandrel having a corrugated groove to perform a wave-setting process. The heating temperature is preferably below the softening point of the fiber. At high temperatures, the fibers melt and become hard. Furthermore, if the temperature is low, the effect of waveform setting processing will not be apparent. Furthermore, since the softening point varies depending on the il+ift used, a range of 120 to 200°C is desirable.

Regarding the processing time, it is important that the crimp state after the waveform setting process does not easily deform.Dry heat treatment requires time for heat transfer, but wet heat treatment using an autoclave or steam to set the waveform can shorten the process time. Since the setting effect appears over time, it also varies depending on the material of the mandrel with the corrugated grooves used and the fiber tube used. For this reason, it is desirable to carry out the process for about 1 to 60 minutes, although this cannot be said completely.

Thereafter, it is cooled to below the glass transition point. If the mandrel with corrugated grooves is pressed against the mandrel or the mandrel is removed during high temperature cooling, the crimp condition applied to the fiber tube will weaken and it will quickly deform or become blocked. It is desirable to cool down to below the glass transition point.

The cooling method may be by leaving it as it is, forcing air or cold air to cool it, or cooling it by immersing it in water. Thereafter, the fiber tube is removed from the corrugated mandrel.

The fiber cylinders crimped by these methods have a uniform limp shape and are excellent in extensibility, flexibility, and rigidity.

Moreover, it can be easily carried out in an economical manner and on a mass production basis without using complicated methods or tools.

[Example] EXAMPLES The present invention will be explained in more detail with reference to Examples below.

Example-1 The warp yarn and the weft yarn (@ yarn) are made of polyethylene terephthalate 50 denier 36 filament temporarily twisted yarn, and the weft surface yarn is made of polymer array composite fiber with 78 parts of island component polyethylene terephthalate and sea component polystyrene. 22
Using a fiber M245 denier 40 filament with 36 sheets and 36 sheets, weaved it into a tube shape with a so-called warp and warp double weave structure to form a fiber tube with an inner diameter of 19 mmφ and a length of 1 m, washed with hot water, and then dried. The polystyrene was then removed with trichlene.

Next, a raising oil agent was applied to this fiber cylinder, and then the fiber was raised using a raising machine. Next, water jet punching treatment was performed and drying was performed. The inner diameter of the fiber cylinder at this time is 10.1
mmφ, and the condition of the fiber cylinder after drying is folded and wrinkled.
Twisting was observed.

A stainless steel cylindrical straight tube with a diameter of 1 Q mm was inserted into this fiber tube, and the tube was shaped into a circular tube (corrugated pretreatment) using a hot air dryer at 130° C. for 10 minutes. Thereafter, it was taken out of the hot air dryer and left to cool to room temperature, and the cylindrical straight pipe was rolled out. At this time, the mm tube-and-pile-like object had no folding or wrinkles, and it maintained a solid cylindrical shape.

Next, when a mandrel having a spiral waveform groove of 1 Q mm in diameter was inserted into this fiber tube, it could be inserted smoothly.

After that, when stainless steel wire Q, 2 mmφ was sequentially wound at a tension of 500Q along the pitch of the mandrel having wavy grooves, each time the stainless steel wire was wound, the fibrous cylindrical object smoothly had wavy grooves. It was sent sliding down the mandrel and tightly wrapped around the recesses of the corrugated groove.

Next, a heat treatment was performed at 180° C. for 30 minutes in a hot air dryer to perform a wave-setting process. Thereafter, it was taken out of the hot air dryer and left to cool to room temperature, the stainless steel wire was removed, and the fibrous cylindrical object was removed from the mandrel having the corrugated grooves.

The artificial blood vessel that had been twisted had a regularly uniform limp shape, did not twist even when stretched, and was elongated uniformly.

Even when I bent it roughly, it didn't bend. That is, it had excellent extensibility and flexibility.

Comparative Example 1 Using the same thread as in the example, water jet punching was carried out in the same manner as in the example, and the process was carried out until drying. The inner diameter of the fiber cylinder at this time is 10. The condition of the fibrous cylinder with a diameter of 1 mm and 92 dryness showed folds, wrinkles, and twists. A mandrel having a spiral waveform groove of iQmmφ was inserted into this fiber tube, but it was difficult to slip because it got caught on the tip of the waveform. After that, it was wrapped with a stainless steel wire of 0.2 mmφ and wound with a tension of 500 Cl along the pitch of the mandrel with the corrugated grooves, but the fiber tube did not slip easily and the stainless steel wire could not reach the corrugated recesses, so it was not possible to wrap it by hand. I sent him a fiber cylinder. Next, a heat treatment was performed at 180° C. for 30 minutes in a hot air dryer to set the waveform. Thereafter, it was taken out of the hot air dryer and left to cool to room temperature, and the stainless steel wire was removed. The obtained artificial blood vessel had a non-uniform crimp shape, with some shallow parts and some deep parts, probably due to poor smoothness of the fibrous tubular material. Also, uneven fiber density was observed. When this was pulled, different areas of elongation were observed. When I roughly bent it, I found that the shallow part of the crimp shape was bent.

Comparative Example 2 A yarn was used in the same manner as in the example and subjected to tarjet punching and drying. The inner diameter of the fiber tube at this time was 10.1 mmφ, and the condition of the fiber tube after drying was observed to be bent, wrinkled, and twisted. According to Japanese Patent Application Laid-open No. 52-70597, a mandrel having an annular wave-shaped groove of '1Qmmφ was inserted into the male part of the ifi fiber tube, and then pressed with a mold having the same shape and dried in a hot air dryer for 130 minutes.
A first heat treatment was performed at a temperature of .degree. C. for 10 minutes.

Thereafter, it was left to cool to room temperature. It was then removed from the mold with the corrugated grooves. A glass tube with approximately the same diameter as the inner diameter of the fiber tube was inserted into the bond, and one end was fixed to the glass tube. Then the other end was shortened to the fixed one. If the convex parts of the waveform were shortened so that they touched each other, it could be shortened uniformly, but if the convex parts did not touch each other, the crimps would be dense at both ends and rough in the center, and the crimp could not be uniformly shortened. Since it was difficult to shorten the length, a second heat treatment was performed with the protrusions in contact with each other. The heating temperature is 18
After 30 minutes at 0''C, it was left to cool to room temperature.The crimp shape of the resulting artificial blood vessel was almost uniform and had good extensibility, but it had a very hard texture. .

[Effects of the Invention] By adopting such a configuration, the present invention brings about the following extremely large effects.

(1) A uniform, regular, or limp-shaped artificial blood vessel is created, and it also has excellent extensibility and flexibility.

(2) The fiber structure of the artificial blood vessel can be made with very little variation in fiber density.

(3) It is economical because it can be easily carried out on a mass production basis.

Claims (1)

[Claims] (1) When inserting a mandrel having a spiral or annular wave groove into a fibrous cylindrical object and heating it to set the corrugation, the inner diameter of the fibrous cylindrical object must be 1. A method for manufacturing an artificial blood vessel, which comprises inserting a cylindrical or cylindrical straight tube close to the shape of the waveform, and shaping it into a cylindrical shape at a temperature that is at least 10° C. lower than the waveform setting processing temperature, but still allows shaping.