Bioabsorbable cotton-like material and method for manufacturing bioabsorbable cotton-like material

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 highly absorbent bioabsorbable cotton-like material 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 instruments. By using bioabsorbable materials, the instruments are absorbed into the body and disappear after fulfilling their function, eliminating the need for a second surgery to remove them, thereby improving safety. Specifically, nonwoven fabrics made of bioabsorbable materials, such as those disclosed in Patent Document 1, are used as substrates to prevent leakage of bodily 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 a variety of medical applications. For example, in surgical procedures, cotton is used to absorb bodily fluids. Because the cotton used in such surgical procedures can be accidentally left unattended, there is a growing demand for cotton made from bioabsorbable materials to ensure safety in the event that it is forgotten. However, most conventional bioabsorbable materials are flat nonwoven fabrics, which present the problem of being difficult to fabricate into a cotton-like form. Furthermore, conventional nonwoven fabrics made from bioabsorbable materials have the problem of low water absorbency, making it even more difficult to obtain a highly 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 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 cm 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, the cotton-like material can be made bioabsorbable. Furthermore, since polyglycolide decomposes relatively quickly, it can be absorbed into the body in a shorter period of time. Furthermore, by using polyglycolide, the material can have physical properties closer to cotton. Here, cotton-like material refers to a material in which fibers are entangled and in a low-density mass.

[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. When the weight-average molecular weight of the polyglycolide is 30,000 or more, the strength of the obtained bioabsorbable cotton-like material can be increased, and when it is 200,000 or less, the decomposition rate can be increased. 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, resulting in a cotton-like structure. 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 average fiber diameter mentioned above means the average value obtained by cutting out a central portion of the bioabsorbable cotton-like material and measuring the fiber diameter at 10 random locations using an electron microscope.

[0010] The bioabsorbable cotton-like material of the present invention has a specific volume of 50 cm 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, which will be described later, can be easily adjusted to the range described later. The specific volume is 55 cm 3 / g or more, and 60cm 3 / g or more is more preferable, and 95cm 3 / g or less, and 3 The specific volume can be adjusted by the manufacturing conditions of the bioabsorbable cotton-like material. The specific volume can be measured by the following method.

[0011] First, the obtained bioabsorbable cotton-like material is cut into a 20 x 20 cm sample and stacked until the mass reaches approximately 40 g to obtain a test specimen. The obtained test specimen is then left for 1 hour and weighed. Next, a 14 g thick plate is placed on the test specimen, and a 63 g weight A is placed on it for 30 seconds, after which weight A is removed and the specimen is left for 30 seconds. This procedure is repeated three times, and after the third time, the heights of the four corners of the test specimen are measured and the average value is calculated. Based on the average heights of the four corners obtained, the specific volume is calculated using the following formula. The test is performed on three test specimens, and the specific volume is expressed as the average of the three measurements. 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 sufficiently absorb body fluids and be used as a substitute for cotton even when used in surgical procedures. 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 measured specifically 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. Then, remove the sample from the water and hang it vertically for 120 seconds. After the test, measure the weight to the nearest 0.1 mg. Based on the obtained weight, 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 of 5 tests)

[0014] The bioabsorbable cotton-like material of the present invention can be produced by using a melt-blowing method to discharge polyglycolide and by controlling the nozzle temperature and the distance between the nozzle and the conveyor within specific ranges. Conventional methods have made it difficult to produce cotton-like material using bioabsorbable materials, and they could only be produced in the form of a flat nonwoven fabric. However, the present invention makes it possible to easily produce a bioabsorbable cotton-like material by using the above-mentioned production method. This method for producing a bioabsorbable cotton-like material of the present invention, which includes a step of ejecting a polyglycolide solution by melt-blowing under conditions where 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, also constitutes 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 melt-blowing under conditions where 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. By setting the nozzle temperature and the nozzle-to-conveyor distance within the above ranges, the crystallization of the extruded polyglycolide fibers is slowed down, allowing the fibers to be entangled with nearby fibers to a moderate degree, and the entangled polyglycolide fibers can be deposited on the conveyor at a low density. As a result, a cotton-like material satisfying the above average fiber diameter, specific volume, and water retention rate, which was previously unrealizable, can be obtained. The nozzle temperature is preferably 30° C. or higher and 40° C. or lower than the melting point of polyglycolide. 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 regular cotton in the medical field. In particular, because the present invention has excellent bioabsorbability and water absorption, it is highly effective in applications such as packing it around an affected area to absorb bodily fluids during surgical operations. By using the present invention in surgical operations, even if the bioabsorbable cotton-like material is left inside the body, it is absorbed into the body over time and disappears, making it highly safe. [Effects of the Invention]

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

[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 Bioabsorbable cotton-like materials were obtained by using the melt-blowing method to extrude threads made of polyglycolide with a weight-average molecular weight of 120,000 and a melting point of 223°C. The specific conditions for the melt-blowing method were: nozzle-to-conveyor distance 80cm, polymer extrusion rate 0.1kg / h, air velocity near the extrusion outlet 50m / s, 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, Handicraft 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 Example. The results are shown in Table 1.

[0023] (1) Measurement of average fiber diameter The central part of the obtained bioabsorbable cotton or cotton was photographed at 1000x magnification using a scanning electron microscope (SEM). Ten fiber portions 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 or cotton was first cut into a 20 x 20 cm sample and stacked until the mass reached approximately 40 g to obtain a test specimen. The resulting test specimen was then left for 1 hour and weighed. A 14 g thick plate was then placed on the test specimen, followed by a 63 g weight A for 30 seconds. Weight A was then removed and the specimen was left for 30 seconds. This procedure was repeated three times, and the heights of the four corners of the test specimen after the third measurement were measured and averaged. The specific volume was calculated using the following formula based on the average heights of the four corners obtained. The test was performed on three test specimens, and the average of the three measurements was used. 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 described above, and then a 126 g weight B was placed on the test piece for 30 seconds, and the heights of the four corners of the test piece were measured again. Weight B was then removed, and the heights of the four corners of the test piece were measured again 3 minutes later. The measured heights of the four corners were each averaged, and the compression ratio and recovery ratio were calculated using the three average values ​​according to the following formula. The test was performed on three test pieces, and the values ​​were expressed as the average of the three measurements. 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 rate of the bioabsorbable cotton-like material and cotton was measured according to a method in accordance with JIS L 1912-1997, and the water absorbency was evaluated. Specifically, the initial weight of the sample under standard conditions was measured, and the sample was then placed underwater in a container filled with water for 180 seconds. The sample was then removed from the water and hung vertically for 120 seconds. After the test, the weight was measured to within 0.1 mg. Based on the obtained weight, 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 of 5 tests)

[0027] [Table 1]

[0028] From Table 1, it can be seen that the nonwoven fabric of the example 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 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: It consists 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.

2. A bioabsorbable cotton-like material for medical use, comprising: It consists 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.

3. A method for producing the bioabsorbable cotton-like material according to claim 1 or 2, comprising: The method includes a step of discharging a polyglycolide solution 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 the 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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