KR101361452B1 - Nonwoven Web for Blood Filter and Method for Manufacturing The Same - Google Patents

Abstract

Disclosed are a nonwoven web for a blood filter and a method of manufacturing the same, which have an optimal average pore diameter and minimum diameter coefficient of variation that can simultaneously satisfy a high leukocyte removal rate and a low red blood cell damage rate. The nonwoven web for blood filters of the present invention comprises a plurality of short fibers. Each of the short fibers, polyethylene terephthalate; And polybutylene terephthalate, wherein a weight ratio of the polyethylene terephthalate and the polybutylene terephthalate is 1: 1 to 1:19. The short fibers have an average diameter of 1 to 5 μm. The nonwoven web has an average pore diameter of 8 to 12 μm and a short fiber diameter variation coefficient of 15 CV% or less.

Description

Nonwoven Web for Blood Filter and Method for Manufacturing the Same {Nonwoven Web for Blood Filter and Method for Manufacturing The Same}

The present invention relates to a non-woven web for blood filters and a method for manufacturing the same, and more particularly, to a non-woven web for blood filters for removing white blood cells and a method for producing the same.

Blood transfusions containing white blood cells or red blood cell concentrates can cause a variety of side effects, including headaches, vomiting, chills, fever, viral infections, and allogen sensitization. To prevent these side effects, white blood cells must be sufficiently removed from blood prior to transfusion.

Methods for removing leukocytes from blood include centrifugation to rotate blood at high speed, a filter method for adsorbing and removing white blood cells on a filter, and a text field for inhaling and removing leukocyte layers generated by adding and mixing text lines to blood. Law, etc. Among these, a filter method having excellent leukocyte removal performance, easy operation and low cost is widely used.

Among various kinds of substrates for the blood filter used in the filtering method is a nonwoven fabric. Blood filters must meet a variety of needs. First, in order to prevent blood from clotting during the leukocyte removal process, the blood filter must have a fast blood throughput, ie high blood affinity. Second, the blood filter should have a high leukocyte removal rate to prevent the side reactions described above. Third, the blood filter must have a low red blood cell damage rate in order to pass smoothly without damaging other useful components in the blood, such as red blood cells.

On the other hand, all medical devices, including blood filters are subjected to sterilization immediately after manufacture. Representative sterilization methods include ethylene oxide (EO) gas sterilization and high temperature steam sterilization.

According to ethylene oxide gas sterilization, one of the most common sterilization processes, medical devices are exposed to ethylene oxide gas for 6 to 16 hours at a temperature of 38 ° C to 65 ° C and a humidity of 40% RH to 58% RH. In particular, according to the high temperature steam sterilization, the medical device is sterilized at a high temperature of 100 ℃ to 130 ℃.

This sterilization process raises the temperature of the medical device itself, and this temperature rise may change the shape, color, dimensions, etc., which are inherent characteristics of the product.

The change in shape and dimensions due to the sterilization process in the blood filter is a very serious problem in that it changes the leukocyte removal rate and the erythrocyte damage rate.

Accordingly, the present invention relates to a non-woven web for blood filters and a method of manufacturing the same that can prevent problems caused by the above limitations and disadvantages of the related art.

One aspect of the present invention is a non-woven fabric for blood filters having an optimal thermal pore size and minimum diameter variation coefficient that can satisfy both high white blood cell removal rate and low red blood cell damage rate, as well as excellent thermal dimensional stability. To serve the web.

Another aspect of the present invention is to produce a non-woven web for blood filters having an optimal thermal pore size and minimum diameter variation coefficient that can satisfy both high white blood cell removal rate and low red blood cell damage rate as well as excellent thermal dimensional stability. Is to provide a way.

Other features and advantages of the invention will be set forth in the description which follows, or may be learned by those skilled in the art from the description.

According to an aspect of the present invention as described above, a non-woven web for blood filters comprising a plurality of short fibers, each of the short fibers, polyethylene terephthalate; And polybutylene terephthalate, wherein a weight ratio of the polyethylene terephthalate and the polybutylene terephthalate is 1: 1 to 1:19, and the short fibers have an average diameter of 1 to 5 μm, and the nonwoven web Is provided with a nonwoven web for blood filters, which has an average pore diameter of 8 to 12 μm and a short fiber diameter variation coefficient of 15 CV% or less.

According to another aspect of the invention, blending polyethylene terephthalate and polybutylene terephthalate in a weight ratio of 1: 1 to 1:19 for the production of spinning dope; Spinning the spinning dope through detention; Thinning the short fibers formed by the spinning step using an air jet; And it provides a non-woven web manufacturing method for a blood filter comprising the step of collecting the tapered short fibers.

The foregoing general description of the present invention is intended to be illustrative of or explaining the present invention, but does not limit the scope of the present invention.

According to the blood filter nonwoven web of the present invention and its manufacturing method, since the nonwoven web has an optimum average pore diameter and minimum diameter variation coefficient, it is possible to manufacture a blood filter that satisfies the high leukocyte removal rate requirement and the low red blood cell damage rate simultaneously. have.

At the same time, since the blood filter manufactured by the nonwoven web of the present invention has excellent thermal dimensional stability, the shape and dimensional change that may occur during the high temperature sterilization process are minimized, and as a result, the leukocyte removal rate and erythrocyte damage rate caused by the sterilization process are minimized. The fluctuation can be minimized.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Therefore, the present invention encompasses all changes and modifications that come within the scope of the invention as defined in the appended claims and equivalents thereof.

Hereinafter, a nonwoven web for blood filter and a method of manufacturing the same according to an embodiment of the present invention will be described in detail.

The nonwoven web for blood filters of the present invention comprises monofilaments. Short diameter short fibers are physically or chemically entangled with each other to form a three-dimensional structure. Due to the short fibers forming the three-dimensional structure, the nonwoven web contains a large number of pores.

In order for the blood filter to satisfy both high white blood cell removal rate and low red blood cell damage rate, the filter substrate nonwoven web should have the optimal average pore size and minimum diameter variation coefficient to selectively adsorb only white blood cells and allow red blood cells to pass smoothly. do.

In order to selectively adsorb only white blood cells having a diameter of 12 to 15 μm and to allow red blood cells having a diameter of 6 to 8 μm to pass smoothly, the nonwoven web of the present invention should be prepared to have an average pore size of 8 to 12 μm.

On the other hand, in consideration of leukocyte removal performance and economy, it is preferable that the short fibers of the nonwoven web have an average diameter of 1 to 5 탆. If the average diameter of the short fibers is less than 1 μm, the pressure loss is too high when the blood is filtered, and the practicality of the blood filter is decreased. If the average diameter of the short fibers exceeds 5 μm, the probability of contact between the white blood cells and the short fibers is high. Because of this, the white blood cell removal rate of the blood filter may drop.

In addition, the nonwoven web preferably has a short fiber diameter variation coefficient of 15 CV% or less. The short fiber diameter variation coefficient is defined as the ratio of the standard deviation to the average diameter of the short fibers, and the lower the short fiber diameter variation coefficient, the shorter fibers in the nonwoven web have a uniform diameter. Since the uniform diameters of the short fibers of the nonwoven web may allow blood to flow uniformly throughout the blood filter, the blood filter may have excellent blood processing efficiency and constant blood processing performance.

In order to produce a nonwoven web for blood filters that satisfies all of the above demanding requirements, a material that facilitates control of the average pore diameter and short fiber diameter of the nonwoven web and the like and enables uniform spinning should be used.

Nonwoven webs for blood filters can be made from various materials, such as natural or thermoplastic fibers such as cellulose. Nonwoven webs made of natural fibers have good affinity with blood, but have high manufacturing costs, uneven physical properties, and poor strength. On the other hand, nonwoven webs made of thermoplastic fibers have the advantage of having relatively uniform properties and relatively low manufacturing costs.

In particular, polyethylene terephthalate (PET) in thermoplastic fibers has relatively good stiffness and atmosphere corrosion resistance, and does not have a fast crystallization rate, which facilitates radiation control and enables uniform spinning. Has an advantage. The advantage of such polyethylene terephthalate is essential in the manufacture of nonwoven webs for blood filters that require strict control over the average pore diameter, short fiber diameter, and short fiber diameter variation coefficient of the nonwoven web. Thus, the short fibers of the nonwoven web of the present invention comprise polyethylene terephthalate.

However, the nonwoven web made of only polyethylene terephthalate resin is hardened and brittle when exposed to a high temperature of 80 ° C. or more for a long time, and has a problem of decreasing pore size due to heat shrinkage. This problem makes it difficult to manufacture the nonwoven web for blood filters of the present invention with only polyethylene terephthalate resin. Accordingly, the nonwoven web of the present invention further includes other thermoplastic resins that can alleviate the problems of polyethylene terephthalate in addition to polyethylene terephthalate, i.e., minimize the shape and dimensional changes of blood filters that may occur during high temperature sterilization processes. shall.

Polybutylene terephthalate (PBT) is one of the thermoplastic resins that can alleviate the problems of polyethylene terephthalate while satisfying the basic physical properties required for the blood filter nonwoven web. Polybutylene terephthalate has the highest crystallization rate after polyoxymethylene (POM) in crystalline polymers.

Specifically, since the glass transition temperature (Tg) of polybutylene terephthalate is at least 40 ° C. or lower lower than that of polyethylene terephthalate, polybutylene terephthalate has a relatively high crystallization rate compared to polyethylene terephthalate. Therefore, nonwoven webs made of polybutylene terephthalate have superior thermal dimensional stability compared to nonwoven webs made of polyethylene terephthalate, so that the average pore diameter and short fiber of the nonwoven web after high temperature sterilization process There is almost no change in the diameter and the short fiber diameter variation coefficient.

However, when the nonwoven web is manufactured through the meltblown process using only polybutylene terephthalate, the average pore diameter of the nonwoven web and the diameter of the short fiber are increased because the crystallization of the polybutylene terephthalate proceeds too fast. , And it is difficult to strictly control the short fiber diameter variation coefficient and the like, and therefore, it is difficult to set the spinning conditions correctly.

As a result, in order to not only have an optimal average pore diameter and minimum short fiber diameter coefficient of variation that can simultaneously satisfy high leukocyte removal rate and low red blood cell damage rate, but also have excellent thermal dimensional stability to withstand high temperature sterilization process, Each of the short fibers constituting the nonwoven web for blood filter of the present invention includes polyethylene terephthalate and polybutylene terephthalate. The weight ratio of polyethylene terephthalate and polybutylene terephthalate is preferably 1: 1 to 1:19.

When the weight of the polybutylene terephthalate is less than the weight of the polyethylene terephthalate, the non-woven web's machine direction (MD) heat shrinkage rate and / or cross direction (CD) heat shrinkage rate is 1.0%. And the shape and dimensions of the blood filter during the high temperature sterilization process are unacceptably changed. The longitudinal heat shrinkage and the widthwise heat shrinkage of the nonwoven web are obtained by measuring the length change after exposing the nonwoven web for 9 hours at a temperature of 65 ° C. and a relative humidity of 58%.

On the other hand, if the weight of polybutylene terephthalate exceeds 19 times the weight of polyethylene terephthalate, it becomes difficult to strictly control the average pore diameter, short fiber diameter, and short fiber diameter variation coefficient of the nonwoven web, and in particular, spinning The uniformity of is lowered so that the coefficient of variation in the short fiber diameter of the nonwoven web exceeds 15 CV%, making it impossible to secure both high white blood cell removal rate and low red blood cell damage rate.

Since each of the short fibers constituting the nonwoven web for blood filter of the present invention includes polyethylene terephthalate and polybutylene terephthalate in a weight ratio of 1: 1 to 1:19, the nonwoven web of the present invention is 1.0% or less. It can be made to have a longitudinal heat shrinkage rate, a widthwise heat shrinkage rate of 1.0% or less, and a short fiber diameter variation coefficient of 15 CV% or less.

In order to improve the blood treatment rate, the nonwoven web of the present invention may further include a hydrophilic coating layer. Such a coating layer may include a polymer having a nonionic hydrophilic group. The polymer having a nonionic hydrophilic group can be obtained by polymerizing a monomer such as 2-hydroxyethyl methacrylate.

Hereinafter, a method of manufacturing the nonwoven web for blood filter of the present invention will be described in detail.

First, polyethylene terephthalate and polybutylene terephthalate are blended in a weight ratio of 1: 1 to 1:19 to prepare the spinning dope. Polyethylene terephthalate is prepared using a germanium-based catalyst and has a glass transition temperature of 60 ° C or higher. In contrast, polybutylene terephthalate has a glass transition temperature of 60 ° C. or less.

Subsequently, the non-woven web is produced with the spin dope using a meltblown method. In more detail, the spinning dope is spun through the detention. The short fibers coming out of the detention are tapered using an air jet. This thin short fibers are collected on the collector.

At this time, in order to control the average pore diameter, short fiber diameter, and short fiber diameter variation coefficient of the nonwoven web, the spinning temperature, air pressure, and die to collector distance (DCD) should be appropriately adjusted.

According to one embodiment of the invention, in order to produce a nonwoven web made of short fibers having a fineness of uniform diameter, spinning temperature of 280 to 300 ℃, air pressure of 0.7 to 1.5 kgf / ㎠, and 60 to The meltblown process is carried out under a DCD of 100 mm.

If the spinning temperature is lower than 280 ° C., short fibers having a diameter of less than 5.0 μm cannot be obtained because the short fibers are not sufficiently drawn, and the binding force between the short fibers stacked on the collector is excessively lowered, so that the mechanical properties of the nonwoven web are reduced. There is a problem that the physical properties are lowered. On the other hand, when the spinning temperature is higher than 300 ° C., the bonding force between the short fibers stacked on the collector is so strong that the flexibility of the nonwoven web is low, and when it is higher than the optimum condition, the flexibility is reduced due to excessive bonding of the fibers, and 8 to 12 μm. There is a problem that it is not easy to adjust the pore size of the nonwoven web to have an average pore diameter.

On the other hand, when the air pressure is less than 0.7 kgf / ㎠ it is not possible to obtain a short fiber having a diameter of less than 5.0 ㎛ as short fibers are not sufficiently drawn. On the other hand, when the air pressure is more than 1.5 kgf / ㎠ may cause the blowing of the fiber may be difficult to obtain a non-woven web of a uniform shape accordingly.

The blood filter made of the nonwoven web obtained through the above method has an excellent leukocyte removal rate of 98% or more and an erythrocyte recovery rate of 85% or more. Therefore, the blood filter can be used in a blood purification apparatus requiring excellent leukocyte removal rate and erythrocyte recovery rate.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. It should be noted, however, that the following examples are intended to assist the understanding of the present invention, and the scope of the present invention should not be limited thereby.

Example 1

Polyethylene terephthalate resin having an intrinsic viscosity of 0.52, a glass transition temperature of 79 ° C., and a melting temperature of 257 ° C., a polybutylene tere having a intrinsic viscosity of 0.75, a glass transition temperature of 35 ° C., and a melting temperature of 220 ° C. The phthalate resin was blended in a weight ratio of 1: 9 to prepare a spinning dope. Subsequently, in the conventional melt blown nonwoven fabric manufacturing apparatus, the air pressure and the speed of the collector were adjusted to make fibers having an average diameter of 2 μm, having a weight per unit area of 30 g / m 2, and an average thickness of 0.15 mm. Nonwoven webs were made. Spinning temperature was 285 ℃, DCD (Die to Collector Distance) was 70mm.

Example 2

A nonwoven web was prepared in the same manner as in Example 1 except that the DCD was 90 mm.

Example 3

A nonwoven web was prepared in the same manner as in Example 1 except for blending the weight ratio of polyethylene terephthalate resin and polybutylene terephthalate resin in a weight ratio of 1: 7.

Example 4

A nonwoven web was prepared in the same manner as in Example 1 except for blending the weight ratio of polyethylene terephthalate resin and polybutylene terephthalate resin in a weight ratio of 1: 8.

Example 5

A nonwoven web was prepared in the same manner as in Example 1 except for blending the weight ratio of polyethylene terephthalate resin and polybutylene terephthalate resin in a weight ratio of 1:10.

Example 6

A nonwoven web was prepared in the same manner as in Example 1 except for blending the weight ratio of polyethylene terephthalate resin and polybutylene terephthalate resin in a weight ratio of 1:11.

Example 7

A nonwoven web was prepared in the same manner as in Example 1 except for blending the weight ratio of polyethylene terephthalate resin and polybutylene terephthalate resin in a weight ratio of 1: 1.

Example 8

A nonwoven web was prepared in the same manner as in Example 1 except for blending the weight ratio of polyethylene terephthalate resin and polybutylene terephthalate resin in a weight ratio of 1:19.

Comparative Example 1

A nonwoven web was prepared in the same manner as in Example 1 except for blending the weight ratio of the polyethylene terephthalate resin and the polybutylene terephthalate resin in a weight ratio of 2: 1.

Comparative Example 2

A nonwoven web was prepared in the same manner as in Example 1 except for blending the weight ratio of polyethylene terephthalate resin and polybutylene terephthalate resin in a weight ratio of 1:20.

Comparative Example 3

A nonwoven web was prepared in the same manner as in Example 1 except that the spinning dope was made only with polyethylene terephthalate resin having an intrinsic viscosity of 0.52, a glass transition temperature of 79 ° C., and a melting temperature of 257 ° C.

Comparative Example 4

A nonwoven web was prepared in the same manner as in Example 1 except that the spinning dope was made of only polybutylene terephthalate resin having an intrinsic viscosity of 0.75, a glass transition temperature of 35 ° C., and a melting temperature of 220 ° C. .

Comparative Example 5

A nonwoven web was prepared in the same manner as in Comparative Example 4 except that the DCD was 90 mm.

The heat shrinkage rate, fiber diameter, change rate, pore size, and heat shrinkage rate of the nonwoven webs obtained by the above examples and comparative examples were obtained by the following method, and the results are shown in Table 1 below.

Thermal shrinkage of nonwoven webs (%)

The heat shrinkage rate of the nonwoven web was measured using a thermohygrostat (Tabai Espec Corp, PL-F). After exposing the nonwoven web for 9 hours at a temperature of 65 ° C and a relative humidity of 58%, the length before and after heat treatment was measured before and after heat treatment in the longitudinal direction (MD) and the cross direction (CD), respectively. The ratio of reduced length to was calculated.

Average pore diameter of nonwoven web (μm)

The average pore diameter (μm) of the nonwoven web constituting the blood filter was indirectly measured using an electron microscope image analyzer (model name: JSM6700F, manufacturer: JEOL, measurement magnification: 1.0K). Specifically, an image of the nonwoven web is obtained through electron microscope image analysis. Subsequently, the area A of the void portion of the image, that is, the portion recognized as black in the electron microscope image is obtained. In addition, the number of effective voids B, which is the number of black image fragments that can be viewed as actual voids, is represented by a certain area, rather than a defect or shadow on the image, among the portions recognized as black in the electron microscope image. Then, using A and B, the cell density was obtained by the following formula, and the average pore diameter of the nonwoven web was obtained by the following formula using the cell density and the constant.

Constant = density of raw polymer / density of nonwoven

Cell density = (B / A x 100) ^3/2 x 10 ⁹ x Constant

Average pore diameter = [(constant -1) x 6 / (? X cell density)] ^1/3 × 10 ⁴

Short Fiber Fluctuation Coefficient (CV%)

The coefficient of variation of the short fibers constituting the nonwoven web of the blood filter was determined using a scanning electron microscope and an image analyzer (using the JVC Digital Camera KY-F70B in the software of Image-Pro Plus). First, the diameter of each of the 20 samples was measured, and then the average diameter and standard deviation of the short fibers were calculated. Subsequently, the short fiber diameter variation coefficient was calculated | required according to the following formula using the average diameter and standard deviation of short fiber.

Coefficient of variation (CV%) = (standard deviation / mean diameter) × 100

division Weight ratio
(PET / PBT) DCD
(mm) Short Fiber Diameter Variation Coefficient
(CV%) Average pore size
(탆) MD / CD Heat Shrinkage
(%)
Example 1 1: 9 70 14.6 10.3 0.5 / 0.5 Example 2 1: 9 90 12.5 11.6 0.5 / 0.4 Example 3 1: 7 70 14.3 10.7 0.8 / 0.8 Example 4 1: 8 70 14.4 10.8 0.6 / 0.6 Example 5 1:10 70 14.7 10.4 0.5 / 0.4 Example 6 1:11 70 14.8 10.4 0.4 / 0.4 Example 7 1: 1 70 14.2 10.9 1.0 / 0.9 Example 8 1:19 70 14.9 10.1 0.2 / 0.1 Comparative Example 1 2: 1 70 14.1 9.9 2.2 / 1.9 Comparative Example 2 1:20 70 21.2 11.1 0.1 / 0.1 Comparative Example 3 1: 0 70 13.9 9.5 6.0 / 5.5 Comparative Example 4 0: 1 70 25.4 7.8 0/0 Comparative Example 5 0: 1 90 24.5 14.3 0/0

As shown in Table 1, the nonwoven webs of Examples 1 to 8 in which the weight ratio of polyethylene terephthalate and polybutylene terephthalate are 1: 1 to 1:19 are all 1.0% or less in longitudinal thermal shrinkage and 1.0% or less. The thermal shrinkage in the width direction is shown. On the contrary, in Comparative Example 1 in which the weight ratio of polyethylene terephthalate and polybutylene terephthalate is 2: 1, both the longitudinal heat shrinkage and the widthwise heat shrinkage were 1.9% or more, and without polyethylene terephthalate, polyethylene terephthalate was found. In the case of Comparative Example 3 prepared only with phthalate, both the longitudinal heat shrinkage rate and the widthwise heat shrinkage rate were found to be 5.5% or more.

As for the short fiber diameter coefficient of variation, the nonwoven webs of Examples 1 to 8, in which the weight ratio of polyethylene terephthalate and polybutylene terephthalate are 1: 1 to 1:19, all have a short fiber diameter coefficient of variation of 15 CV% or less. It can be seen that the short fibers have a relatively uniform diameter. On the contrary, in Comparative Example 2 in which the weight ratio of polyethylene terephthalate and polybutylene terephthalate is 1:20, the short fiber diameter variation coefficient was found to be more than 20 CV%, and only polybutylene terephthalate without polyethylene terephthalate was used. In the case of the prepared Comparative Example 4, the short fiber diameter variation coefficient was found to be 25 CV% or more.

On the other hand, except that the DCD was changed from 70mm to 90mm, the nonwoven web of Comparative Example 5 manufactured by the same method as Comparative Example 4 had an average pore diameter nearly twice that of the nonwoven web of Comparative Example 4 appear. From this fact, it can be seen that when the nonwoven web is manufactured using only polybutylene terephthalate without polyethylene terephthalate, the control of the process is difficult because the physical properties of the nonwoven web are greatly changed by only a small change in process conditions. On the contrary, in Examples 1 and 2, when the nonwoven web was prepared by blending polyethylene terephthalate and polybutylene terephthalate in a weight ratio of 1: 9, the average pore difference of the nonwoven web was changed even when the DCD was changed from 70 mm to 90 mm. It can be seen that the process control is relatively easy because it is as small as 1.3 μm.

Claims (7)

In the nonwoven web for blood filters comprising a plurality of short fibers,
Each of the short fibers,
Polyethylene terephthalate; And
Polybutylene terephthalate,
The weight ratio of the polyethylene terephthalate and the polybutylene terephthalate is 1: 1 to 1:19,
The short fibers have an average diameter of 1 to 5 μm,
The nonwoven web has a mean pore diameter of 8 to 12 μm and a short fiber diameter variation coefficient of 15 CV% or less. The method of claim 1,
The nonwoven web has a longitudinal shrinkage of 1.0% or less and a transverse shrinkage of 1.0% or less when exposed to 9 hours at a temperature of 65 ° C. and a relative humidity of 58%. 3. The method of claim 2,
The polyethylene terephthalate has a glass transition temperature of 60 ℃ or more,
The polybutylene terephthalate is non-woven web for blood filter, characterized in that having a glass transition temperature of less than 60 ℃. Blending polyethylene terephthalate and polybutylene terephthalate in a weight ratio of 1: 1 to 1:19 for spinning dope preparation;
Spinning the spinning dope through detention;
Thinning the short fibers formed by the spinning step using an air jet; And
Method for producing a nonwoven web for blood filter, characterized in that it comprises the step of collecting the thin short fibers. 5. The method of claim 4,
The polyethylene terephthalate has a glass transition temperature of 60 ℃ or more,
The polybutylene terephthalate is a nonwoven fabric web manufacturing method for a blood filter, characterized in that it has a glass transition temperature of less than 60 ℃. 5. The method of claim 4,
The spinning step is a non-woven web manufacturing method for a blood filter, characterized in that carried out under a spinning temperature of 280 to 300 ℃. The method according to claim 6,
The air jet is a non-woven web manufacturing method for a blood filter, characterized in that provided at an air pressure of 0.7 to 1.5 kgf / ㎠.