JPH01232972A - Blood filter - Google Patents

Abstract

PURPOSE:To reduce the damage of blood corpuscles and to make a leucocyte removing rate and an erythrocyte recovery rate excellent, by constituting a filter of nonwoven fabric using a synthetic fiber having predetermined monofilament fineness and a profile cross-section whose surface area increase rate is a specific value or more. CONSTITUTION:The fineness of the monofilament of a synthetic fiber constituting a blood filter is set to 0.25 denier or less, pref., to 0.1 denier or less and the cross-section of the monofilament has an odd-shape and the surface area increase ratio F=l/(4pis)1/2(wherein l is the average outer peripheral length of the monofilament cross-section and s is the average cross-section of the monofilament cross-section) is 1.15 or more. This synthetic fiber is in an opened state. Since the synthetic fiber constituting the blood filter has the profile cross-section, an increasing surface area increase ratio is 1.15 or more, pref., 1.30 or more as compared with a round cross-sectional fiber and the surface area increase ratio of 1.15 or less is not pref. because the enhancement of the removal rate of a leucocyte is less as compared with the round cross-sectional fiber. By this method, even when the diameter of a fiber is not made too small and a filling rate is not enhanced, the contact surface area of the fiber with a leucocyte is increased, and a leucocyte removing rate and an erythrocyte recovery rate are made excellent.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a blood filter, and particularly to a filter for removing white blood cells from body fluids containing white blood cells, lymph fluid, and their processing. The present invention relates to a leukocyte removal filter that causes less blood cell damage and has an excellent leukocyte removal rate and red blood cell recovery rate by specifying the shape characteristics and structure.

(Prior Art) Recent thinking regarding blood transfusion has shifted from the traditional whole blood axis to components tailored to the needs of the patient. That is, conventional whole blood transfusions and red blood cell concentration fluid transfusions often cause side effects such as fever, headache, and nausea due to the inconvenience of histocompatibility antigens in patients receiving these transfusions. Therefore, for general blood transfusions that only require red blood cells, it has come to be considered that it is better to transfuse blood that contains only red blood cells and contains as few extra components as possible.

Methods for removing leukocytes from whole blood are broadly classified into centrifugation, dextran sedimentation, and filter methods, but the filter method is currently being studied primarily due to its ease of operation and low cost. Regarding the filter method, efforts have been made to improve leukocyte removal performance and separation efficiency by examining fiber materials and filling methods, especially by adjusting fiber diameter and filling rate.
It is known that by decreasing the fiber diameter and increasing the filling rate in No. 5, the fiber surface that comes into contact with leukocytes increases and the leukocyte removal rate improves.

However, it is difficult to reduce the fiber diameter only to a certain extent, and when the filling rate is increased, white blood cells become clogged and the removal rate decreases in a short period of time.

(Problems to be Solved by the Invention) The present invention has been made by focusing on the above-mentioned problems. In other words, the object is to increase the surface area of the fibers in contact with leukocytes without reducing the fiber diameter too much or increasing the filling rate, and to provide a leukocyte filter with excellent leukocyte removal rate and red blood cell recovery rate. .

(Means for Solving the Problems) The present invention provides a nonwoven fabric using synthetic fibers having a single fiber fineness of 0.25 denier or less and a modified cross section having a surface area increase ratio F of 1.15 or more as expressed by the following formula. A blood filter characterized in that:

The term "filter" used in the present invention refers to a single layer or a multi-layered nonwoven sheet made of fibers with irregular cross sections.

The fineness of the single fibers of the synthetic fibers constituting the blood filter according to the present invention must be 0.25 denier or less, preferably 0.1 denier or less, and the cross section of the single fibers has an irregular shape and a surface area increase ratio of 1. 15 or more. Such synthetic fibers are characterized by being in an opened state, which increases the surface area of the fibers and exhibits a leukocyte removal effect with excellent leukocyte removal rate and red blood cell recovery rate.

If the fineness of the synthetic fibers constituting the blood filter of the present invention exceeds 0.025 denier, it is not preferable because the contact area with white blood cells decreases, leukocyte removal performance is poor, and drapability and softness are also poor due to the irregular cross-sectional effect. . If the fineness is too fine, the single fibers forming the structure are easily deformed by weak force, so the preferable fineness is from 0.05 denier to 0.005 denier.

The cross section of the synthetic fibers constituting the blood filter of the present invention has a modified cross section, so that the surface area increase rate is 1.15 or more, preferably 1.30 or more, compared to round cross section fibers. A surface area increase ratio of less than .15 is not preferred because the leukocyte removal rate is less improved than with round cross-section fibers. Here, the larger the surface area increase ratio is, the more preferable it is, but from the viewpoint of manufacturing, it is estimated that about 10 is the limit. The cross-sectional shape of the synthetic fiber is not particularly limited.

The synthetic fibers constituting the blood filter of the present invention are not particularly limited as long as they are synthetic polymers that can be melt-spun, such as polyester, polyamide, polyolefin, polyacrylonitrile, polyvinyl chloride, etc., but preferably polyester, polyamide, fully aromatic fibers, etc. Examples include polymers with relatively high modulus such as group polymers, and those that can provide properties such as heat resistance, chemical resistance, and weather resistance.

The bulk density of the nonwoven fabric constituting the filter of the present invention is 0.
05-0.5 g/cIi1, preferably 0. 1~0
．． 3g/CTa, eye = tt O-100g/cJ The nonwoven fabric is a single layer or multiple layers laminated.

Example 1 Using the melt blow nozzle shown in Fig. 1 (1 in the figure indicates the orifice hole and 4 indicates the excessive detection end),
Polyethylene terephthalate No. 5 was made into ultrafine fibers having an irregular cross section of 0.023 denier and a surface area increase ratio of 1.42 by using a conventional melt blowing method with an orifice hole equivalent diameter of 0.4 mmφ and a nozzle of the type shown in FIG. 2 (E). The basis weight consists of 40
A nonwoven fabric with g/Cml and a thickness of 10 mm was obtained.

Fifteen of the filters were stacked and placed in a filter holder with an effective diameter of 8 cm, and the leukocyte removal performance of fresh blood added with ACD was evaluated. Evaluation was performed by measuring the number of blood cells in blood sampled from the inlet and outlet channels of the test filter using a microsyringe using a Coulter Counter (manufactured by Coulter Electronics). Blood flow rate: 401 d/m, blood volume: 500 d
Table 1 shows the leukocyte removal rate and red blood cell recovery rate.

Example 2 Polyethylene terephthalate with an intrinsic viscosity of 0.65 was
Orifice hole shape shown in figure (c) (round equivalent φ0.4m
A nonwoven fabric was produced using the nozzle (n) under the same conditions as in Example 1. The properties of the obtained nonwoven fabric were that the fineness was 0.023, the fabric weight was 40 g/cl, and the surface area increase ratio was 1.32.

The same evaluation as in Example 1 was performed, and the results are shown in Table 1.

Example 3 Polyethylene terephthalate having an intrinsic viscosity of 0.65 was prepared using an orifice-shaped nozzle as shown in FIG. 2 (c). Example 1
Under the same conditions as 0.015 denier, surface area increase ratio 1.
A nonwoven fabric containing the fibers of No. 3 and having a basis weight of 40 g/cffl was obtained. The leukocyte removal effect is shown in Table 1.

Comparative Example 1 The orifice shape is as shown in Fig. 2 (a) and φ0
．． A nonwoven fabric was produced under the same conditions as in Example I except that 3 mm was used. The characteristics of the obtained nonwoven fabric are fineness of 0.046
g/d, basis weight 40g/Cl11, surface area increase ratio 1.00
Met. The same evaluation as in Example 1 was performed and the results were
Shown in the table.

Comparative Example 2 A nonwoven fabric was produced under the same conditions as in Example 1, except that the nozzle (equivalent round diameter φ0.4+++m) shown in FIG. 2(c) was used as the orifice shape.

The characteristics of the obtained nonwoven fabric are fineness of 0.012 g/d and basis weight of 4.
The surface area increase ratio was 0 g/ci and 1.10.

Evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

The following is an engraving of the margin specification (no changes to the content) (Effects of the invention) The present invention is configured as described above, and the fiber surface area is increased by specifying the diameter and cross-sectional shape of the fibers constituting the nonwoven fabric. It is now possible to provide a leukocyte removal filter that also has excellent leukocyte removal properties.

[Brief explanation of the drawing]

Figure 1 shows a spinning nozzle using the melt blow method;
The figure shows the hole shape of the spinning nozzle and the cross section of a single fiber.

Claims (1)

[Claims] (1) A blood filter characterized by being composed of a nonwoven fabric made of synthetic fibers having a single fiber fineness of 0.25 denier or less and a modified cross section with a surface area increase ratio F of 1.15 or more expressed by the following formula. . F=l/√(4πs) [However, l is the average outer circumference length (cm) of the single fiber cross section, and s
is the average cross-sectional area (cm^2) of a single fiber cross-section. ]