Organism absorbent cotton-like material and method for manufacturing the same

Abstract

To provide an organism absorbent cotton-like material with high water absorption and a method for manufacturing the organism absorbent cotton-like material.SOLUTION: An organism absorbent cotton-like material used for medical applications is composed of polyglycolide and has an average fiber diameter of 0.5-7.0 μm. A specific volume measured with a method according to JIS L 1097 is 50-100 cm3 / g, and a water retention value measured with a method according to JIS L 1912-1997 is 150% or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a bioabsorbable cotton-like material having high water absorption properties and a method for producing the bioabsorbable cotton-like material. [Background technology]

[0002] In the medical field, bioabsorbable materials are sometimes used as materials for surgical tools. By using bioabsorbable materials, they are absorbed into the body and disappear after fulfilling their role, so there is no need to perform another surgery to remove them, and safety can be improved. Specifically, nonwoven fabrics made of bioabsorbable materials such as those disclosed in Patent Document 1 are used as substrates to prevent leakage of body fluids and air. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-76586 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, cotton is routinely used in the medical field for a variety of purposes. For example, cotton is used in surgery to absorb bodily fluids. Since the cotton used in such surgery may be forgotten to be removed, there is an increasing demand for cotton made of bioabsorbable materials to ensure safety in the event that it is forgotten to be removed. However, most conventional bioabsorbable materials are flat nonwoven fabrics, and there is a problem that they are difficult to make into a cotton-like material. In addition, conventional nonwoven fabrics made of bioabsorbable materials have a problem of low water absorption, making it even more difficult to obtain a highly water-absorbent bioabsorbable cotton-like material.

[0005] In view of the above problems, an object of the present invention is to provide a bioabsorbable cotton-like material having high water absorption properties and a method for producing the bioabsorbable cotton-like material. [Means for solving the problem]

[0006] The present invention relates to a bioabsorbable cotton-like material for medical use, which is made of polyglycolide, has an average fiber diameter of 0.5 μm or more and 7.0 μm or less, and has a specific volume of 50 cm3 as measured by a method in accordance with JIS L 1097. 3 / g or more 100cm 3 / g or less, and the water retention rate measured by a method in accordance with JIS L 1912-1997 is 150% or more. The present invention will be described in detail below.

[0007] The bioabsorbable cotton-like material of the present invention is made of polyglycolide. By using polyglycolide as a material, it is possible to impart bioabsorbability to the cotton-like material. In addition, since polyglycolide decomposes relatively quickly, it can be absorbed into the body in a short period of time. Furthermore, by using polyglycolide, it is possible to achieve physical properties closer to those of cotton. Note that the cotton-like material here refers to a material in which fibers are entangled and in a low-density mass state.

[0008] The weight average molecular weight of the polyglycolide is not particularly limited, but is preferably 30,000 or more and 200,000 or less. The strength of the obtained bioabsorbable cotton-like material can be increased by making the weight-average molecular weight of polyglycolide 30,000 or more, and the decomposition rate can be increased by making the weight-average molecular weight of polyglycolide 200,000 or less. The weight-average molecular weight of the polyglycolide is more preferably 50,000 or more, and more preferably 150,000 or less.

[0009] The bioabsorbable cotton-like material of the present invention has an average fiber diameter of 0.5 μm or more and 7.0 μm or less. When the average fiber diameter of the fibers constituting the bioabsorbable cotton-like material is within the above range, the fibers are appropriately entangled with each other when produced by the melt-blowing method, so that the cotton-like material can be formed. The average fiber diameter is preferably 1.0 μm or more, more preferably 1.5 μm or more, and is preferably 5.0 μm or less, and more preferably 3.0 μm or less. The average fiber diameter can be adjusted by the production conditions. The above-mentioned average fiber diameter means that a part in the center of the bioabsorbable cotton-like material is cut out, and the fiber diameter is measured at 10 random points using an electron microscope, and then the average is obtained.

[0010] The bioabsorbable cotton-like material of the present invention has a specific volume of 50 cm3 as measured by a method in accordance with JIS L 1097. 3 / g or more 100cm 3 / g or less. By setting the average fiber diameter and specific volume within the above ranges, the shape and physical properties can be made closer to those of cotton. In addition, the water retention rate described below can be easily adjusted to the range described below. The specific volume is 55 cm 3 / g or more, and 60 cm 3 / g or more is more preferable, and 3 / g or less, and 3 The specific volume can be adjusted by the production conditions of the bioabsorbable cotton-like material. The specific volume can be measured by the following method.

[0011] First, the obtained bioabsorbable cotton-like body is cut into a sample of 20 x 20 cm, and stacked until the mass is about 40 g to obtain a test piece. The obtained test piece is then left for 1 hour and weighed. Next, a 14 g thick plate is placed on the test piece, and a 63 g weight A is placed on it for 30 seconds, after which weight A is removed and the test piece is left for 30 seconds. This operation is repeated three times, and the heights of the four corners of the test piece after the third operation are measured and the average value is calculated. Based on the average value of the heights of the four corners obtained, the specific volume is calculated from the following formula. The test is performed on three test pieces, and the specific volume is expressed as the average of the three measured values. Specific volume (cm 3 / g)=(5×5×(h0 / 10)) / W h0: Average height of the four corners of the test piece after weight A is removed (mm) W: Mass of the test piece (g)

[0012] The bioabsorbable cotton-like material of the present invention has a water retention rate of 150% or more as measured by a method in accordance with JIS L 1912-1997. When the water retention rate of the bioabsorbable cotton-like material is within the above range, it can be used as a substitute for cotton even when used in a surgical operation, since it can sufficiently absorb body fluids. The water retention rate is preferably 200% or more, and more preferably 250% or more. There is no particular upper limit to the water retention rate, and the higher the better, but it is, for example, 1000% or less. The water retention rate can be specifically measured by the following method.

[0013] First, measure the initial weight of the sample under standard conditions, then place it underwater in a container filled with water for 180 seconds. After that, remove the sample from the water and hang it vertically for 120 seconds. After the test, measure the weight to within 0.1 mg. Based on the weight obtained, calculate the water retention rate using the following formula. W A =(M N -M K ) / M K ×100 W A :Water retention rate (%) M K : Initial weight (g) (average value of 5 times) M N Weight after test (g) (average value of 5 tests)

[0014] The bioabsorbable cotton-like material of the present invention can be produced by setting the nozzle temperature when discharging polyglycolide using the melt-blowing method and the distance between the nozzle and the conveyor to a specific range. With conventional methods, it was difficult to produce a cotton-like material using a bioabsorbable material, and it could only be produced in the form of a flat nonwoven fabric, but with the present invention, the bioabsorbable cotton-like material can be easily produced by using the above-mentioned production method. Such a method for producing a bioabsorbable cotton-like material of the present invention, which includes a step of ejecting a polyglycolide solution by a melt-blowing method under conditions in which the nozzle temperature is between +20°C and +50°C above the melting point of polyglycolide and the distance between the nozzle and the conveyor is between 50 cm and 150 cm, is also one aspect of the present invention.

[0015] The method for producing a bioabsorbable cotton-like material of the present invention includes a step of extruding a polyglycolide solution by a melt-blowing method under conditions of a nozzle temperature of +20°C or more and +50°C or less of the melting point of polyglycolide and a distance between the nozzle and the conveyor of 50 cm or more and 150 cm or less. By setting the nozzle temperature and the nozzle-to-conveyor distance within the above ranges, the crystallization of the discharged polyglycolide fibers is delayed, so that the fibers can be appropriately entangled with the neighboring fibers, and the entangled polyglycolide fibers can be deposited on the conveyor at a low density. As a result, it is possible to obtain a cotton-like material that satisfies the above average fiber diameter, specific volume, and water retention rate, which was not possible with the conventional method. The nozzle temperature is preferably at least 30° C. above the melting point of polyglycolide, and is preferably at most 40° C. above the melting point of polyglycolide. Moreover, the distance between the nozzle and the conveyor is preferably 60 cm or more, more preferably 70 cm or more, and is preferably 140 cm or less, more preferably 130 cm or less.

[0016] The bioabsorbable cotton-like material of the present invention is used in the same applications as ordinary cotton in the medical field. In particular, since the present invention has excellent bioabsorbability and water absorption properties, it is very effective in applications such as packing it around the affected area in surgery to absorb body fluids. By using the present invention in surgery, even if the bioabsorbable cotton-like material is left in the body, it is absorbed into the body over time and disappears, so it is highly safe. Effect of the Invention

[0017] According to the present invention, it is possible to provide a highly water-absorbent bioabsorbable cotton-like material and a method for producing the bioabsorbable cotton-like material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The following describes the embodiments of the present invention in more detail, but the present invention is not limited to these embodiments.

[0019] Example 1 A bioabsorbable cotton-like material was obtained by extruding threads made of polyglycolide with a weight-average molecular weight of 120,000 and a melting point of 223°C using the melt-blowing method. The specific conditions for the melt-blowing method were: nozzle-to-conveyor distance 80cm, polymer extrusion rate 0.1kg / h, air speed near the extrusion outlet 50m / sec, conveyor movement speed 1.0m / min, and nozzle temperature 260°C.

[0020] (Reference example 1) Cotton (100% organic cotton) was used as is.

[0021] (Reference example 2) Polyester cotton (100% polyester cotton, Craft Cotton (SW-300) manufactured by Kiyohara Co., Ltd.) was used as is.

[0022] <Physical Properties> The following measurements were carried out on the bioabsorbable cotton-like materials obtained in the Examples and the cotton of the Reference Examples. The results are shown in Table 1.

[0023] (1) Measurement of average fiber diameter The central part of the obtained bioabsorbable cotton-like material or cotton was photographed at 1000 times magnification using a scanning electron microscope (SEM). Ten fiber parts were randomly selected from the obtained image, and the fiber diameters were measured and averaged to determine the average fiber diameter.

[0024] (2) Measurement of specific volume (density) The specific volume, compressibility and recovery rate of the bioabsorbable cotton-like material and cotton were measured according to the method of JIS L 1097. The results are shown in Table 1. Specifically, the obtained bioabsorbable cotton-like material or cotton was first cut into a sample of 20 x 20 cm, and stacked until the mass reached about 40 g to obtain a test piece. The obtained test piece was then left for 1 hour and weighed. Next, a 14 g thick plate was placed on the test piece, and a 63 g weight A was placed on it for 30 seconds, after which the weight A was removed and the test piece was left for 30 seconds. This operation was repeated three times, and the heights of the four corners of the test piece after the third operation were measured to obtain the average value. Based on the average value of the heights of the four corners obtained, the specific volume was calculated from the following formula. The test was performed on three test pieces, and the average of the three measured values ​​was expressed. Specific volume (cm 3 / g)=(5×5×(h0 / 10)) / W h0: Average height of the four corners of the test piece after weight A is removed (mm) W: Mass of the test piece (g)

[0025] (3) Measurement of compression rate and recovery rate The heights of the four corners of the test piece were measured in the same manner as in the measurement of the specific volume, and then a 126g weight B was placed on the test piece for 30 seconds, and the heights of the four corners of the test piece were measured. The weight B was then removed, and the heights of the four corners of the test piece were measured 3 minutes later. The measured heights of the four corners were averaged, and the compression ratio and recovery ratio were calculated from the three average values ​​according to the following formula. The test was performed on three test pieces, and the averages of the three measurements were used. Compression ratio (%) = (h0-h1) / h0 x 100 Recovery rate (%)=(h2-h1) / (h0-h1)×100 h1: Average height of the four corners of the test piece when weight B is placed on it (mm) h2: Average height of the four corners of the test piece after weight B is removed (mm)

[0026] (4) Measurement of water retention rate The water retention of the bioabsorbable cotton-like material and cotton was measured according to a method in accordance with JIS L 1912-1997 to evaluate the water absorbency. Specifically, first, the initial weight of the sample in the standard state was measured, and then the sample was placed under the water for 180 seconds in a container filled with water. The sample was then removed from the water and hung vertically for 120 seconds, after which the weight was measured to within 0.1 mg. Based on the weight obtained, the water retention rate was calculated using the following formula. The results are shown in Table 1. W A =(M N -M K ) / M K ×100 W A :Water retention rate (%) M K : Initial weight (g) (average value of 5 times) M N Weight after test (g) (average value of 5 tests)

[0027] [Table 1]

[0028] From Table 1, it can be seen that the nonwoven fabric of the examples has properties similar to those of cotton and can be used in place of cotton. [Industrial Applicability]

[0029] According to the present invention, it is possible to provide a highly water-absorbent bioabsorbable cotton-like material and a method for producing the bioabsorbable cotton-like material.

Claims

1. A bioabsorbable cotton-like material for medical use, comprising: Made of polyglycolide, The average fiber diameter is 0.5 μm or more and 7.0 μm or less, The specific volume measured according to JIS L 1097 is 50 cm ３ / g or more 100cm ３ / g or less Bioabsorbable cotton-like material.

2. A bioabsorbable cotton-like material for medical use, comprising: Made of polyglycolide, The average fiber diameter is 0.5 μm or more and 7.0 μm or less, The water retention rate measured according to JIS L 1912-1997 is 150% or more. Bioabsorbable cotton-like material.

3. A method for producing the bioabsorbable cotton-like material according to claim 1 or 2, comprising the steps of: The method includes a step of discharging a solution of polyglycolide by a melt-blowing method under the conditions that the nozzle temperature is 20° C. or more and 50° C. or less of the melting point of polyglycolide, and the distance between the nozzle and the conveyor is 50 cm or more and 150 cm or less. A method for producing a bioabsorbable cotton-like material.

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