JP6051786B2 - Medical three-layer tube and three-layer tube extrusion method - Google Patents

Description

  The present invention relates to a medical three-layer tube and a method for extruding the three-layer tube, and more particularly to a medical three-layer tube used for infusion.

  As in an infusion set, there is known a medical article in which a tube is interposed between a medical solution bag containing an infusion preparation and a needle at the tip or between connecting tools. Such medical tubes include not only infusion set tubes but also those of various thicknesses and lengths, and are widely used to conduct liquids. Moreover, since it is used in various medical scenes, the medical tube is required to have a characteristic that is flexible and hardly breaks.

  From this point of view, PVC (polyvinyl chloride) has been widely used for medical tubes.

  In addition, since it is used for medical purposes, it should be used once. Therefore, as a result, there is a situation that a large amount of waste is discharged.

  On the other hand, since chlorinated plastics such as PVC are the main sources of dioxins, in recent years it has been required to reduce their use.

  Further, PVC easily adsorbs a drug and is not suitable for administration of a trace amount of drug, and an internal plasticizer is likely to be eluted. Therefore, in recent years there is a potential demand to avoid the use of PVC medical tubes as much as possible.

  Therefore, a medical tube made of PBD (polybutadiene) may be used as an alternative to PVC. PBD is suitable for medical use because it has a low drug adsorptivity and does not elute a plasticizer. However, PBD has a problem that its breaking strength tends to be several tens of percent smaller than PVC and its elastic modulus is low.

  In the medical field, when the stand that suspends the infusion bag is moved or when a person moves, it may be stretched or hooked. Even if it is not equal to or higher than PVC, considering the safety factor, the breaking strength is as high as possible and elastic. High medical tubes are desired.

JP-A-2005-103192 Japanese Patent No. 3192217 Japanese Patent No. 4419448

  The present invention has been made in view of the above, and an object of the present invention is to provide a general-purpose medical tube that does not substantially adsorb a drug, does not elute a plasticizer, and has a high breaking strength and rich elasticity. .

Medical three-layer tube of claim 1, the inner layer is Ri polybutadiene, the outer layer is polybutadiene der, between the inner and outer layers, mixing of the rupture-resistance material incompatible with the material and polybutadiene which are compatible with the polybutadiene It is a resin, and an intermediate layer with a mechanical lock formed over the entire area of the local weld with the inner layer and outer layer is provided, and molded as a rupture-resistant material with the inner layer, intermediate layer, outer layer, and intermediate layer bonded together It is characterized by that.

That is, the invention according to claim 1 can provide a general-purpose medical tube that has a three-layer structure, substantially does not adsorb a drug and does not elute a plasticizer, and has a high breaking strength and high elasticity. . When a medical tube is manufactured by extrusion molding, when a three-layer tube is molded, each layer needs to be firmly bonded without peeling. In the present invention, since it has a three-layer structure, it is possible to join both layers by providing an intermediate layer even if the combination is such that they are not thermally welded as a result of optimal material selection derived from the required physical properties of the inner layer and outer layer It becomes .

Middle tier, even those incompatible as PBD and TPU as described later, by extruding it was dispersed in each other, and finally mechanical lock according to the material between the intermediate layer is formed In addition, it is possible to obtain a strong extrusion-molded body in which the local welded portions with the inner layer and the outer layer material cover the entire region and are bonded together as a whole . The three layers include an aspect in which a clear layer interface does not necessarily exist.

  Although the thickness of a tube is not specifically limited, For example, an internal diameter can be 0.5 mm-5.0 mm, and an outer diameter can be 2.0 mm-7.0 mm. The ratio of the inner layer thickness to the outer layer thickness can be, for example, in the range of 2: 8 to 8: 2, but 6: 4 from the viewpoint of extrusion moldability and homogeneity. The ratio can be ˜4: 6. Further, the intermediate layer can have a thickness of 10% to 50% of the whole.

Medical three-layer tube of claim 2 is the medical three-layered tube of claim 1, the middle-layer is a mixed resin of a polybutadiene and a thermoplastic polyurethane, polybutadiene: Thermoplastic polyurethane = 25 wt% : 75 wt% to 60 wt%: 40 wt%, blending ratio, thickness is 15% to 50% of the total thickness

  That is, the invention according to claim 2 provides a medical tube that is capable of improving fracture resistance to the same level or higher than PVC while combining materials that have been used for medical purposes, and has easy adhesion or easy joining. It becomes possible.

The invention according to claim 2 can provide a medical tube having a high fracture resistance equal to or higher than that of a conventional PVC tube as well as a single-layer PBD tube. Preferably, polybutadiene: thermoplastic polyurethane = 30 wt%: 70 wt% to 50 wt%: 50 wt%.

The method for extruding a medical three-layer tube according to claim 3 is a method for extruding a medical three-layer tube, wherein the inner layer has a material non-adsorbent and a plasticizer non-eluting property, and the outer layer has Easy-to-adhesive material or easily-bondable material for connectors and other medical connecting parts, intermediate layer, material compatible with both inner layer material and outer layer material, and at least one of inner layer material and outer layer material Using materials that are incompatible with each other and exhibiting fracture resistance , the two materials are mixed by heating and melted, and a mechanical lock is formed between the two materials in the intermediate layer region by extrusion. Further, the present invention is characterized in that a local welded portion with the inner layer material and the outer layer material is spread over the entire region, and a three-layer tube in which the inner layer and the intermediate layer and the outer layer and the intermediate layer are bonded together is obtained as a whole.

In other words, the invention according to claim 3 uses, as a constituent material of the intermediate layer, a material that is not compatible with the inner and outer layers as a result of imparting fracture resistance and other required characteristics while using a material suitable for the required characteristics for each of the inner and outer layers. Even when it is used, a tube suitable for medical use can be obtained. Moreover, it is possible to manufacture using existing equipment without incurring complicated manufacturing processes.

The medical three-layer tube extrusion method according to claim 4 is the medical three-layer tube extrusion method according to claim 3 , wherein the inner layer material and the outer layer material are polybutadiene, and the intermediate layer is polybutadiene and a thermoplastic polyurethane. And the intermediate layer has a polybutadiene: thermoplastic polyurethane = 25 wt%: 75 wt% to 60 wt%: 40 wt% blending ratio and wall thickness of 15% to 50% of the total wall thickness And

That is, the invention according to claim 4 can provide a medical tube having a high fracture resistance equal to or higher than that of a conventional PVC tube as well as a single-layer PBD tube. Preferably, polybutadiene: thermoplastic polyurethane = 30 wt%: 70 wt% to 50 wt%: 50 wt%.

In addition, it is a method for extrusion molding of a three-layer tube , generalizing claim 3 , wherein the intermediate layer is compatible with the inner layer material but not with the outer layer material, and is compatible with the outer layer material and the inner layer. Using a material that is incompatible with the material, the two materials are mixed and melted by heating, and an intermediate layer is formed with the inner and outer layer materials in the intermediate layer interface region by forming a mechanical lock between the two materials in the intermediate layer by extrusion molding. A three-layer tube in which the inner layer and the intermediate layer, and the outer layer and the intermediate layer are bonded as a whole may be obtained by spreading the local welded portion with the intermediate layer material over the entire area.

That is, with this technique, a three-layer tube having various characteristics can be obtained by forming a mechanical lock in the intermediate layer region. Moreover, it is possible to manufacture using existing equipment without incurring complicated manufacturing processes. Note that the two materials of the intermediate layer may be an inner layer material and an outer layer material, respectively, and in this case, a two-layer tube in which the boundary surface is complicated is formed. That is, in this technology , a three-layer tube includes a two-material tube that is a three-layer at the time of extrusion (injection).

According to the present invention, it is possible to provide a general-purpose medical tube that can be used for conducting a trace amount of drug and has high strength and reliability.
In addition, a material suitable for the required characteristics for each of the inner and outer layers is used, and a material that is incompatible with at least one of the inner layer and the outer layer is used as a constituent material of the intermediate layer as a result of having fracture resistance and other required characteristics. However, a tube suitable for medical use can be obtained .

It is explanatory drawing which showed the structural example of the infusion set using the medical three-layer tube of this invention. It is explanatory drawing which showed the cross-sectional conceptual diagram of the medical three-layer tube of this invention. It is the figure which compared the breaking strength about the medical three-layer tube of this invention which varied the composition of the intermediate | middle layer, and the conventional tube. It is a figure showing the result of having measured the relationship between tensile strength and elongation about the medical three-layer tube of this invention, and the conventional tube. It is the figure which showed the result of having inserted and bonded the connection member inside the three-layer tube of this invention, and measuring the tensile strength. It is the figure which showed the result of having measured the tensile strength by varying the thickness ratio of the intermediate | middle layer of the three-layer tube of this invention. It is the figure which showed the result of having varied the thickness etc. of the three-layer tube of this invention, and comparing the tensile strength with the conventional product.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view showing a configuration example of an infusion set using the medical three-layer tube of the present invention. FIG. 2 is an explanatory view showing a conceptual cross-sectional view of the medical three-layer tube of the present invention. For convenience of explanation, the scale of each component is appropriately changed. Here, an example in which a mixed resin of PBD + TPU is used for the intermediate layer will be described.

  As shown in FIG. 1, the infusion set 100 includes an infusion bag 101 in which a drip solution is stored, a tube 102, and a venous needle 103 that punctures a vein (arm) of a patient C. Further, in the middle of the tube 102, there are an infusion tube 104 that makes it possible to visually check the flow rate of the drip solution, and a clamp 105 that adjusts the flow rate of the drip solution.

  The infusion bag 101 is suspended from the stand S, and the drip solution is transferred to the body of the patient C through the tube 102 by gravity. The tube 102 may be relatively long and sometimes pulled strongly, such as reaching the floor with the bed on which the patient C lies.

  Therefore, the tube 102 has a three-layer structure as shown in a cross section in FIG. 2 in order to ensure the breaking strength. The inner layer 121 is made of PBD, the intermediate layer 122 is made of a mixed resin of PBD and TPU, and the outer layer 123 is made of PBD. Although these are tube structures and are in close contact with each other, they are manufactured not by adhering with an adhesive but by adhering each other by extrusion.

  The reason why the PBD is used for the outer layer 123 is to ensure adhesiveness and bondability with other connectors or components such as the infusion bag 101, the venous needle 103, and the drip tube 104. In addition, in order to improve assembly property and operativity, you may add and shape | mold a lubricant.

  The reason why PBD is used for the inner layer 121 is that it is difficult to adsorb chemicals, is suitable for transferring a trace amount of chemicals, and does not elute a plasticizer. Moreover, it is because there is a past use result in the case of PBD. In addition, other parts may be inserted into the tube 102, and adhesiveness and bondability can be ensured by using PBD in the same manner as the outer layer. Although a single-layer tube made of PBD can be used only when a small amount of drug is used, the medical tube is usually transparent, and it is difficult to confirm whether it is made of PBD or PVC, and Sometimes there is no time to check. Therefore, the tube 102 is a three-layer tube so that it can be used without being conscious of the material of the tube when any medicine is conducted, ensuring versatility. In addition, in order to improve bubble removal property, a PBD may be added to the inner layer PBD so as to improve the hydrophilicity and be molded.

  The intermediate layer 122 is a mixed resin layer of PBD and TPU. Although these are not compatible, each pellet is put into an extruder and extruded as a molten mixed resin. Since the inner layer 121 and the outer layer 123 are both PBDs, they are integrated with the PBD part of the intermediate layer material, and the TPU is scattered in a small lump shape, fiber shape, and mesh shape in the intermediate layer region. Responsible for expression. This makes it possible to provide a tube suitable for medical use that takes advantage of the characteristics of both materials.

  The inner layer 121 and the outer layer 123 have the same thickness. However, the thickness is not limited to this, and the inner layer 121 only needs to have chemical adsorption resistance and plasticizer non-eluting properties. It can be. Further, in the intermediate layer 122, when the mixing ratio of TPU is reduced, the thickness of the intermediate layer 122 may be relatively increased. Since the intermediate layer 122 only needs to function as an adhesive member between the inner layer 121 and the outer layer 123 and as a strength developing layer, the thickness of the intermediate layer 122 can be, for example, 15% of the total thickness.

  Next, the tensile strength test of the three-layer tube of the present invention will be described. The three-layer tube was a mixed resin of an outer layer, an inner layer PBD, and an intermediate layer PBD + TPU. As comparative examples, tensile strength was also measured for PVC single-layer tubes (added with plasticizer DEHP), PVC single-layer tubes (added with plasticizer TOTM), and PBD single-layer tubes conventionally used for medical purposes.

  All experiments were standardized with an inner diameter of φ3.2 mm and an outer diameter of φ4.6 mm. For the three-layer tube, the outer layer thickness is 0.30 mm, the intermediate layer thickness is 0.15 mm, the inner layer thickness is 0.25 mm, and the mixing ratio (weight) of PBD and TPU is PBD: TPU = 1: 9, 3: 7, The respective breaking strengths were measured as 5: 5. The results are shown in FIG.

  As is apparent from the figure, it was found that when PBD: TPU = 1: 9 to 3: 7, the fracture resistance is improved more than the conventional PVC.

  Next, the tube holding interval of the intermediate layer PBD: TPU = 3: 7 is set to 30 mm, the tensile speed is set to 200 mm / min, the horizontal axis indicates elongation (strain%), and the vertical axis indicates stress (MPa). The relationship between stress and stress was measured. In addition, here, a conventional tube was also measured, and a three-layer tube in which a mixed resin of polyethylene (PE) + TPU was used for the inner and outer layers PBD and the intermediate layer was also measured. The tube of the intermediate layer PE + TPU has an inner diameter of 2.7 mm and an outer diameter of 4.6 mm (outer layer thickness of 0.25 mm, intermediate layer thickness of 0.40 mm, inner layer thickness of 0.30 mm), and is thicker than other tubes did. The results are shown in FIG.

  As can be seen from the figure, the three-layer tube of the present invention is a tube suitable for use in the medical field because it can be confirmed that the three-layer tube of the present invention can be stretched to follow even when pulled and is not easily cut. I found out. In addition, when the intermediate layer is PE + TPU, a stress reduction is observed in the middle. This indicates that delamination has occurred. In other words, the three-layer tube of the present invention can be said to be an excellent tube having a higher breaking strength than PVC without causing delamination.

  Next, various measurements were performed by adjusting the blending ratio of the intermediate layer (PBD + TPU) and the wall thickness ratio with respect to the entire thickness. The tube has an inner diameter of 3.2 mm, an outer diameter of 4.6 mm, an outer layer thickness of 0.315 mm, an inner layer thickness of 0.315 mm, and the intermediate layer thickness is fixed to 0.07 mm, which is 10% of the total thickness. PBD: TPU = 10 wt%: 90 wt% to 90 wt%: 10 wt%, and samples were prepared with different blending ratios of 10% (both inner and outer layers were made of PBD).

  A PC pipe was inserted and bonded as a connecting member inside the tube, and the tensile strength was measured with a distance between chucks of 40 mm and a tensile speed of 200 mm / min. The results are shown in FIG.

  As shown in the figure, delamination occurred when PBD = 10 wt% and 20 wt%, and tube breakage occurred when the mixing ratio was higher. This is because when the PBD is small, the adhesive portion with the inner and outer layers is small and there are many incompatible TPUs, so peeling occurs between the layers. Conversely, when the PBD is large, the adhesive portion with the inner and outer layers increases. It was considered that the strength expression of PBD was not sufficient, and PBD-derived fracture occurred.

  Particularly preferred is an extrapolation of the measurement results to give a tensile strength of 60 N or more, and the blending ratio is in the range of PBD: TPU = 25 wt%: 75 wt% to 60 wt%: 40 wt%. Preferably, PBD: TPU = 30 wt%: 70 wt% to 50 wt%: 50 wt%, which is 70 N or more. Although not shown, when the blending ratio was similarly changed and the tensile strength of the tube itself was measured across both ends of the tube without being connected to the member, a constant strength of about 100 N in the blending ratio range was obtained. Confirmed to have. Further, regarding the water pressure resistance of the tube, good results of substantially the same level were shown in the above-mentioned blending ratio range. Regarding the kink resistance of the tube, the results were better as the blending ratio of PBD was higher, although it was approximately the same level in the blending ratio range.

  Next, the tensile strength of the tube itself with respect to the thickness ratio of the intermediate layer was measured. The tube had an inner diameter of 3.2 mm and an outer diameter of 4.6 mm, the outer layer thickness was the same as the inner layer thickness, and the thickness of the intermediate layer was varied from 5% to 50% in 5% increments to prepare samples. Here, the inner and outer layer materials were PBD, and the intermediate layer was PBD: TPU = 40 wt%: 60 wt%. The results are shown in FIG. Moreover, the result of the PVC single layer tube of the same shape and the PBD single layer tube was also shown collectively.

  As shown in the figure, it was confirmed that when the thickness ratio was 15% of the whole, it was almost the same level as PVC, and when it exceeded 20%, it was confirmed that a tensile strength higher than PVC was exhibited. Note that when the thickness ratio exceeded 40%, the tensile strength was flat. On the other hand, when the thickness ratio exceeds 50%, the tube becomes hard, and therefore the thickness ratio is preferably 50% or less.

  Finally, the tube thickness and blending ratio thickness ratio were changed, and the tensile strength of the tube itself was compared with the conventional product. FIG. 7 (a) shows the result of using a tube having a large diameter of about 3.2 mm inside diameter x 4.6 mm outside diameter including products of other companies. For the three-layer tube of the present invention, the inner and outer layers (PBD) have the same thickness, the intermediate layer thickness is 20% of the whole, and the PBD: TPU in the intermediate layer is 40 wt%: 60 wt%. FIG. 7B shows the result of using a tube having a small diameter of about 1.0 mm inside diameter and about 2.7 mm outside diameter including products of other companies. In the three-layer tube of the present invention, the inner and outer layers (PBD) have the same thickness, the intermediate layer thickness is 40% of the whole, and the PBD in the intermediate layer: TPU = 50 wt%: 50 wt%. All can confirm that it has the tensile strength equivalent to a PVC single layer tube.

  As shown above, according to the present invention, the present invention provides a novel alternative tube suitable for PVC-free medical use that has the same strength as PVC and does not have drug adsorption or plasticizer elution like PVC. It was confirmed that it was possible.

  In the above experiment, the intermediate layer is made of PBD + TPU, but the intermediate layer can be made of SEBS, SBS, or SEEPS in addition to the same thermoplastic elastomer, that is, TPU, for the purpose of strength development.

  Moreover, even if it is a case where the resin which is not compatible as mentioned above is used, it turns out that the extrusion tube | tube which was firmly joined as a whole can be obtained.

  That is, a method of extruding a medical three-layer tube, wherein the intermediate layer is compatible with at least one of the inner layer material and the outer layer material, and is compatible with at least one of the inner layer material and the outer layer material. This material is a material that does not break, exhibits resistance to breakage, stretchability, and other characteristics. The two materials are mixed and melted by heating, and a mechanical lock is formed between the two materials in the intermediate layer region by extrusion. In this way, a local welded portion with the inner layer material and the outer layer material is spread over the entire region, and a three-layer tube in which the inner layer and the intermediate layer and the outer layer and the intermediate layer are bonded together can be obtained as a whole.

  Further, it is a generalized method of extruding a three-layer tube, in which the intermediate layer is compatible with the inner layer material but not the outer layer material, and the outer layer material is compatible with the inner layer material. Uses incompatible materials, mixes and melts the two materials by heating, and forms a mechanical lock between the two materials in the intermediate layer by extrusion, while forming the inner and outer layer materials and the intermediate layer in the intermediate layer interface region. It is possible to obtain a three-layer tube in which the inner layer and the intermediate layer and the outer layer and the intermediate layer are bonded together as a whole by locally spreading the welded portion with the material.

  As appropriate, put each material in 2 to 3 extrusion molding machines, heat melt or heat mix, inject the material into a mold for forming a three-layer tube, extrude it, and cool it in the cooling water tank immediately downstream What is necessary is just to shape | mold and it has the advantage that the production using the present installation is attained.

  According to the present invention, the present invention can be applied to a tube having a relatively large diameter such as an artificial cardiopulmonary circuit other than an infusion set.

  Also, even in the infusion circuit, so-called upper tubes from the bottle needle to the drip tube, so-called pump tubes downstream from the drip tube, other tubes such as intermediate tubes, extension tubes, kink resistance, component adhesion, etc. However, by appropriately optimizing the material, inner diameter, and outer diameter of the inner / outer / intermediate layer, a more suitable medical tube can be provided.

100 Infusion set 101 Infusion bag 102 Tube 103 Intravenous needle 104 Drip tube 105 Clamp 121 Inner layer 122 Intermediate layer 123 Outer layer S Stand C Patient

Claims (4)

The inner layer is polybutadiene, the outer layer is polybutadiene der is,
Between the inner layer and the outer layer, it is a mixed resin of a material that is compatible with polybutadiene and a fracture-resistant material that is not compatible with polybutadiene, and a mechanical lock is formed over the entire area where the inner and outer layers are welded. Provided an intermediate layer,
A medical three-layer tube characterized by being molded as a fracture-resistant material in which an inner layer and an intermediate layer, and an outer layer and an intermediate layer are bonded. Middle-layer is a mixed resin of a polybutadiene and a thermoplastic polyurethane, polybutadiene: Thermoplastic polyurethane = 25wt%: 75wt% ~60wt% : 40wt% blend ratio, the thickness, 15% of the overall thickness of 50 medical three-layer tube according to claim 1, characterized in that percent was. A method of extruding a medical three-layer tube,
The inner layer is a material with non-drug-adsorbing properties and plasticizer-non-eluting properties, and the outer layer is an easily-adhesive material or an easily-bondable material for connectors and other medical connection parts,
For the intermediate layer, a material that is compatible with both the inner layer material and the outer layer material, and a material that is incompatible with at least one of the inner layer material and the outer layer material and that exhibits fracture resistance ,
The two materials are mixed and melted by heating,
Extrusion molding forms a mechanical lock between the two materials in the intermediate layer region, while spreading the local welds between the inner layer material and the outer layer material over the entire area, so that the inner layer and the intermediate layer as well as the outer layer and the intermediate layer are joined together. A method for extruding a medical three-layer tube, characterized by obtaining a worn three-layer tube. The inner layer material and the outer layer material are polybutadiene, the intermediate layer is a mixed resin of polybutadiene and thermoplastic polyurethane, and the intermediate layer is made of polybutadiene: thermoplastic polyurethane = 25 wt%: 75 wt% to 60 wt%: 40 wt% 4. The method for extruding a medical three-layer tube according to claim 3 , wherein the thickness is 15% to 50% of the total wall thickness.

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