JP6625639B2 - Orthopedic fixation material - Google Patents

Description

  The present invention relates to an orthopedic fixation material.

  As an orthopedic fixation material, a so-called cast material, a material using a thermoplastic resin material as shown in Patent Literature 1 below has been widely used in recent years, instead of a material using conventional gypsum.

  The orthopedic fixation material made of such a thermoplastic resin material can be easily deformed along the affected part of the human body such as a fractured portion by applying heat, and the shape is maintained after solidification. Because it is easy to be done, convenience is high.

JP-A-9-234241

  However, it is necessary to cool or heat the affected part for treatment after fixing it with orthopedic fixing materials, such as cooling to suppress swelling of the affected part, but resin material has poor thermal conductivity Therefore, there is a problem that it is difficult to obtain the effects of cooling and heating.

  The problem to be solved by the present invention is to improve the thermal conductivity of an orthopedic fixation material made of a resin material.

  In order to solve the above problems, the orthopedic fixation material of the present invention uses, as a base material, a resin component containing a heat conductive powder having higher heat conductivity than the resin component. .

  The content of the heat conductive powder in the base material is preferably in the range of 5 to 50% by weight. The average particle size (median diameter) of the heat conductive powder is preferably in the range of 5 to 100 μm.

  The heat conductive powder is preferably an aluminum powder for the reasons described below. Note that the aluminum powder here includes an aluminum alloy powder.

  The resin component preferably has thermoplasticity. The melting point of the thermoplastic resin component is preferably in the range of 40 to 90 ° C.

  Since the resin component and the heat conductive powder are contained in the base material of the orthopedic fixing material, the heat conductivity is improved. If the affected part is fixed with the orthopedic fixing material and then a cooling agent or a heating agent is applied thereto, the affected part can be treated by cooling or heating.

  When aluminum powder is used as the heat conductive powder to be contained in the resin component to improve the heat conductivity, the weight of the orthopedic fixation material is prevented from increasing because the aluminum powder is relatively lightweight. .

Hereinafter, embodiments of the present invention will be described.
The orthopedic fixing material of the embodiment is used for covering and fixing an affected part of a human body such as a fractured part, and has a higher thermal conductivity than an orthopedic fixing material made of a conventional resin material. Good.

  The orthopedic fixation material of the embodiment is composed of a base material containing a resin component and a heat conductive powder having higher heat conductivity than the resin component.

  The type of the resin component is not particularly limited, but in the case of a thermoplastic resin, it is easy to deform along the affected part of the human body by applying heat, and the shape is easily maintained after solidification, so it is easy to handle. preferable.

  Examples of such a resin include polyester biodegradable resins such as polycaprolactone (PCL), polylactic acid, and polyglycolic acid; polyester resins such as polyethylene terephthalate (PET) excluding biodegradable resins; polyethylene (PE); Examples thereof include polyolefin-based resins such as PP), and a mixture of these resins may be used.

  The content of the resin component in the base material is not particularly limited, but is preferably in the range of 50 to 95% by weight.

  If the content is less than 50% by weight, the orthopedic fixation material becomes brittle and easily breaks or breaks when it is placed along the affected part. On the other hand, if the content exceeds 95% by weight, the rate of improvement in the thermal conductivity of the orthopedic fixation material cannot be expected even if the below-described heat conductive powder is blended. In addition, the thermal conductivity of the resin component itself is very low, and is 0.1 to 0.5 W / m · K.

  The melting point of the thermoplastic resin is not particularly limited. However, if the orthopedic fixing material is adjusted so as to be softened by hot water at a common temperature, the handling is easy, and the melting point is in the range of 40 to 90 ° C. Is preferably within the range.

  Among them, polycaprolactone is particularly preferable because it is easily thermally deformed with hot water in the range of about 50 to 80 ° C. and has good shape memory after solidification.

  The heat conductive powder is contained in the resin component in order to improve the heat conductivity of the orthopedic fixing material.

  The heat conductive powder may be any heat conductive powder having a higher heat conductivity than the resin component, and the type thereof is not particularly limited. For example, metal powders such as aluminum, gold, silver, copper, nickel, iron, and stainless steel, and inorganic powders such as silicon carbide, aluminum nitride, alumina, and carbon are exemplified. In addition, by applying a chemical treatment such as plating to the surface of a powder having a low thermal conductivity such as a resin powder, a powder having a high thermal conductivity having a metal film or an inorganic compound film formed on the surface can also be used. .

  The heat conductive powder is particularly preferably a heat conductive powder having a thermal conductivity of 100 W / m · K or more at 20 ° C., and a thermal conductive powder having a heat conductivity of 200 W / m · K or more at 20 ° C. Is more preferable. Among these, aluminum powder (including an aluminum alloy) that is inexpensive, easily available, relatively lightweight, and has high heat dissipation is preferred. In this case, an increase in the weight and cost of the orthopedic fixing material can be suppressed.

  Metal powders such as aluminum powder have a surface made of a layer made of an inorganic substance such as a metal oxide such as silicon, titanium, or aluminum or a hydroxide of a similar metal, or a layer made of an organic substance such as a resin or an organic compound. Surface treatment such as coating may be performed. When such a surface treatment is performed, it is possible to suppress corrosion of the metal powder due to adhesion of moisture such as sweat to a portion directly in contact with the skin and deterioration of the resin component due to the corrosion. In addition, if the patient has a metal allergy, such surface treatment can prevent direct contact between the skin and the metal powder, and can suppress the occurrence of metal allergy. It becomes possible. As a countermeasure against metal allergy, it is possible to use a heat conductive powder composed of an inorganic powder other than the metal powder.

  Further, the shape of the heat conductive powder is not particularly limited, and examples thereof include spherical, granular, plate, and flake shapes.

  When aluminum powder is used as the thermal conductive powder, it may be either aluminum alone or an aluminum alloy.

  When mixing the heat conductive powder with the resin component, the heat conductive powder may be mixed alone or, in order to facilitate the handling, mixed with a master batch that is contained in the carrier resin. Is also good.

  Although the type of the carrier resin is not particularly limited, polyethylene such as low density polyethylene (LDPE) and polyethylene wax can be exemplified. The content of the thermally conductive powder in the masterbatch is not particularly limited, but may be in the range of 60 to 80% by weight.

  The content of the thermally conductive powder in the substrate is not particularly limited, but is preferably in the range of 5 to 50% by weight. More preferably, it is in the range of 10 to 30% by weight. In particular, if the content is within the range of 10 to 30% by weight, when it is contained in the orthopedic fixing material, all of the moldability, thermal conductivity and flexibility are moderately satisfied within a range where there is no problem in use. It becomes possible.

  If the content is less than 5% by weight, the rate of improvement in the thermal conductivity of the orthopedic fixing material decreases. On the other hand, if the content exceeds 50% by weight, the weight of the orthopedic fixation material increases, and the orthopedic fixation material becomes brittle and easily cracks or breaks when it is placed along the affected part.

  The average particle size of the heat conductive powder is not particularly limited, but is preferably in the range of 5 to 100 μm in median diameter (D50).

  If the average particle diameter is less than 5 μm, it becomes difficult to handle the powder. On the other hand, if the average particle size exceeds 100 μm, it is difficult to uniformly disperse the resin component in the resin component, and there is a possibility of overheating, so that it is difficult to impart desired thermal conductivity to the orthopedic fixing material.

  The average particle size of the heat conductive powder can be measured by a known particle size distribution measuring method such as a laser diffraction method.

  Next, the content of the present invention will be further clarified by giving Examples and Comparative Examples of the present invention.

  As a heat conductive powder used in the orthopedic fixing material of the example, a masterbatch containing aluminum powder, METAX NEO (trade name) “NME010T6” manufactured by Toyo Aluminum Co., Ltd. was prepared.

  The average particle size of the aluminum powder contained in the masterbatch is 10 μm, the carrier resin is a mixture of low-density polyethylene and polyethylene wax, and the content of the aluminum powder in the masterbatch is 70% by weight.

In addition, three types of resin components as base materials used in the orthopedic fixing materials of Examples and Comparative Examples were thermoplastic polycaprolactones “Capa ^™ 6400”, “Capa ^™ 6500” and “Capa ^™ 6800” manufactured by Perstorp. Was prepared.

Here, “Capa ^™ 6400” has a molecular weight of 37000 g / mol, a melt flow index (MFI) of 40 dg / min at 160 ° C., and a melting point of 58 to 60 ° C. Further, “Capa ^™ 6500” has a molecular weight of 50,000 g / mol, a melt flow index (MFI) of 7 dg / min at 160 ° C., and a melting point of 58 to 60 ° C. “Capa ^™ 6800” has a molecular weight of 80,000 g / mol, a melt flow index (MFI) of 3 dg / min at 160 ° C., and a melting point of 58 to 60 ° C.

  Using these aluminum powder and the resin component, a sample of a molded product was prepared by an injection molding machine as described later, and Examples A1 to A3, Examples B1 to B3, and Examples shown in Table 1 were prepared. Each of Examples C1 to C3 and Comparative Examples of Comparative Example A1, Comparative Example B1 and Comparative Example C1 were prepared.

As a resin component, in Table 1, Comparative Example A1 and Examples A1 to A3 are “Capa ^™ 6400”, Comparative Examples B1 and Examples B1 to B3 are “Capa ^™ 6500”, Comparative Examples C1 and C1. As for C3, “Capa ^™ 6800” was used.

  In Table 1, PCL indicates polycaprolactone as a substrate, AL indicates aluminum as an aluminum powder, and PE indicates a mixture of low-density polyethylene and polyethylene wax as a carrier resin.

  Moldability test: Injection molding of a sample having a size of 49 mm x 79 mm x 2.5 mm was attempted by using a commonly used injection molding machine at a molding temperature of 180 ° C using the materials of these Examples and Comparative Examples. . The evaluation criteria are as follows. ○ indicates that molding was possible without any problem. Δ indicates that molding was possible but defects such as cracks occurred on the surface of the molded body. × indicates that molding was not possible. In the formulations of the examples in Table 1, all were ○.

  Thermal conductivity test: The samples of Examples and Comparative Examples prepared by these moldability tests were evaluated for thermal conductivity. The evaluation of the thermal conductivity was performed by connecting a temperature sensor to “Thermo Recorder RT12” manufactured by ESPEC as a measuring device and confirming the temperature change on the sample surface. Specifically, when a cooling sheet (“Cooling sheet” manufactured by Toyo Aluminum Echo Products Co., Ltd.) is attached to the back of a sample molded to 49 mm × 79 mm × 2.5 mm, a temperature sensor is installed at the center of the surface of the sample. By doing so, a temperature change after a lapse of 30 minutes was confirmed (thermal conductivity test 1). Similarly, a change in temperature when a heating element ("Warm Aid extending thermal tape" manufactured by Toyo Aluminum Echo Products Co., Ltd.) was adhered to the back surface of the same sample was confirmed (thermal conductivity test 2). The measurement was performed under the conditions of room temperature 25 ° C. and humidity 22%. In Table 2, a comparative example serving as a reference was evaluated as 1 (the temperature change was the smallest), and the case where the temperature change was very high (the thermal conductivity was very good) was set to 5, and the evaluation was performed by a five-step evaluation. . The average of the evaluation results of the thermal conductivity test 1 and the thermal conductivity test 2 is shown in the column of the thermal conductivity test in Table 2.

  Flexibility test: The samples of Examples and Comparative Examples were bent at 180 ° C. under a temperature condition of 80 ° C., and the occurrence of breaks and cracks was observed to evaluate the flexibility. After bending, the sample surface (the surface that becomes outside when bent) has no visible cracks or the like, and the sample has some visible cracks or the like, and the triangle has the cracks extending from the front surface to the back surface. And the one in which a crack penetrated occurred was judged as x. Table 2 shows the results.

As shown in Table 2, there is no problem in molding in any of the examples, and it can be seen that the thermal conductivity is better than that of the comparative example. The difference in the evaluation in the thermal conductivity test in each example is presumed to be due to the difference in the content of the aluminum powder.

Further, as another example, using various heat conductive powders shown in “Types of heat conductive powder” in the following Table 3, the composition of the heat conductive powder and the resin component shown in the same table was used. A moldability test, a thermal conductivity test, and a flexibility test were performed in the same manner as described above. Table 4 shows the results.

In Table 3, resin-coated AL is a resin-coated aluminum powder in which the surface of an aluminum powder is coated with a resin layer, and silica (silicon oxide) -coated AL is silica-coated aluminum in which the surface of an aluminum powder is coated with silica (silicon oxide). Powder, PCL is polycaprolactone as a base material, PE is a mixture of low-density polyethylene and polyethylene wax as a carrier resin, and PBSA is an aliphatic polyester obtained by condensation polymerization of glycol and dicarboxylic acid as a base material. Certain polybutylene succinate adipates (manufactured by Showa Polymer Co., Ltd., trade name: Bionole 5001G, melting point: 79.3 ° C.) are shown.

In Example A4, a masterbatch obtained by mixing the resin-coated aluminum powder with the carrier resin was prepared, and the masterbatch was mixed with polycaprolactone as a base material. The average particle size of the resin-coated aluminum powder contained in the masterbatch is 10 μm, the carrier resin is a mixture of low-density polyethylene and polyethylene wax, and the content of the resin-coated aluminum powder in the masterbatch is 70% by weight. is there.

Similarly, Example A5 was prepared by preparing a masterbatch obtained by mixing silica (silicon oxide) -coated aluminum powder with a carrier resin, and mixing this with polycaprolactone as a base material. The average particle size of the silica (silicon oxide) aluminum powder contained in the masterbatch is 10 μm, the carrier resin is a mixture of low-density polyethylene and polyethylene wax, and the content of silica (silicon oxide) -coated aluminum powder in the masterbatch The amount is 70% by weight.

  As shown in Table 4, it can be seen that, regardless of which thermal conductive powder was used, the thermal conductivity was better than those of Comparative Examples shown in Tables 1 and 2. The difference in evaluation in the thermal conductivity test in each example is due to the difference in thermal conductivity depending on the type of each thermal conductive powder. Further, in Tables 2 and 4, the evaluations of the thermal conductivity tests of Examples A4 and A5 were lower than those of Examples A3 and D1 using aluminum powder. This is probably due to a slight decrease in the thermal conductivity caused by the surface treatment of the aluminum powder used in the above, but it still has a sufficiently good thermal conductivity.

  The embodiments and examples disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the invention is set forth by the following claims, and is intended to include all modifications and variations within the scope.

Claims (4)

An orthopedic fixation material using a base material containing a resin component having thermoplasticity and a heat conductive powder having higher heat conductivity than the resin component,
The content of the heat conductive powder in the base material is in the range of 5 to 50% by weight,
An orthopedic fixation material for treating an affected area by cooling or heating the affected area by applying a cooling agent or a heating agent from above the fixed area.   The orthopedic fixation material according to claim 1, wherein an average particle diameter (median diameter) of the heat conductive powder is in a range of 5 to 100 m.   The orthopedic fixation material according to claim 1, wherein the heat conductive powder is an aluminum powder.   The orthopedic fixation material according to any one of claims 1 to 3, wherein a melting point of the thermoplastic resin component is in a range of 40 to 90 ° C.