JP4072166B2 - Method for manufacturing flexible tube for endoscope - Google Patents

Description

The present invention relates to a method for manufacturing a flexible tube for an endoscope , and more particularly to a method for manufacturing a flexible tube for an endoscope having excellent resistance to autoclave sterilization.

  A flexible tube of a conventional endoscope is usually configured by covering a spiral tube with a mesh tube and covering a flexible outer skin. For example, a polyurethane elastomer is generally used as the outer skin.

  Since the endoscope is used repeatedly, it is necessary to perform cleaning and disinfection each time. In recent years, in order to avoid endoscopic patient-to-patient infection, sterilization with peroxide-based disinfectant or ethylene oxide gas, which has a very strong sterilizing power, and also in a high-pressure steam atmosphere with excellent sterilizing power Autoclave sterilization is performed.

  When a conventional polyurethane elastomer is used as an outer skin of a flexible tube for an endoscope, there are the following drawbacks.

  1. When the heat resistance and chemical resistance are not sufficient and it is used repeatedly, the polyurethane elastomer in the outer skin gradually deteriorates, the flexibility of the flexible tube is lowered, and the insertability into the body is deteriorated. Further, when the deterioration further progresses, a crack occurs in the outer skin, and the outer skin eventually peels off and falls off.

  2. Polyurethane elastomers cannot be used for autoclave sterilization because they will hydrolyze when contacted with high temperature and high pressure steam.

  In order to improve the chemical resistance of the polyurethane elastomer as described above and the resistance to autoclave sterilization, it has been proposed that the outer skin is composed of a material obtained by adding a hydrolysis inhibitor to the polyurethane elastomer (see, for example, Patent Document 1). ).

  However, even by adding a hydrolysis inhibitor, it is difficult to sufficiently suppress the hydrolysis of the polyurethane elastomer, and only an effect of delaying the progress of the deterioration of the polyurethane elastomer can be obtained. It will come.

  In addition, since a material different from polyurethane elastomer, which is a hydrolysis inhibitor, is added, the dispersibility and compatibility between the polyurethane elastomer and the hydrolysis inhibitor are likely to be insufficient, and the polyurethane elastomer can There is a risk of separation of the hydrolysis inhibitor and eventually peeling of the outer skin.

  In order to improve the chemical resistance of a polyurethane elastomer, a technology is known in which a polyurethane resin, which is a material having excellent chemical resistance, is mixed with a polyurethane elastomer to form an outer skin (for example, see Patent Document 2).

  However, even if a polyolefin resin is added, hydrolysis of the polyurethane elastomer cannot be sufficiently suppressed. In addition, since different materials are mixed, there is a problem caused by insufficient dispersibility and compatibility as described above. Furthermore, since the polyolefin resin has low adhesion, the adhesion with the coating layer deposited on the outer skin is poor, and when the flexible tube is immersed in the disinfectant solution, the coating layer may be peeled off and fall off. In order to avoid this, a step of applying a primer or applying a surface treatment is newly required.

  Further, as another conventional example, a technique of mixing silicone rubber or fluororubber having better chemical resistance with various elastomers (polyurethane elastomer, polyester elastomer, polyolefin elastomer) is also known (for example, see Patent Document 3).

However, polyurethane elastomers and polyester elastomers are easily hydrolyzed, and mixing with silicone rubber or fluoro rubber has the same problems of dispersibility and compatibility as above, and silicone rubber, fluoro rubber, and polyolefin elastomer are adhesive. The coat layer may peel off and fall off.
JP 2001-346754 A Japanese Patent Laid-Open No. 2000-245485 JP 2001-161632 A

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a flexible tube for an endoscope that has excellent durability against sterilization treatment.

In order to solve the above problems, an embodiment of the present invention includes a step of covering a spiral tube with a mesh tube, a step of covering an outer periphery of the mesh tube with a skin containing a polymerized polyolefin elastomer, and a crystal of the polymerized polyolefin elastomer Provided is a method for manufacturing a flexible tube for an endoscope, comprising a step of heat-treating at a melting temperature or higher and a step of coating a coat layer on the outer periphery of the outer skin.

  Unlike non-polymerized polyolefin elastomers, polymerized polyolefin elastomers are rich in flexibility and excellent in chemical resistance and hydrolysis resistance. The endoscope flexible tube exhibits excellent resistance to disinfectant chemicals and autoclave sterilization.

  In addition, after coating the outer skin, heat treatment is performed at a temperature equal to or higher than the crystal melting temperature of the polymerized polyolefin elastomer, so that the reticular tube and the outer skin are firmly bonded, and the adhesion between the outer skin and the coat layer on it is dramatically improved. It is possible to improve.

  In this case, the outer skin can contain a mixture of two or more polymerization-type polyolefin elastomers having different hardnesses. As described above, the flexibility of the flexible tube can be finely adjusted by using a mixture of two or more kinds of appropriately selected polymerization type polyolefin elastomers.

  Moreover, a fluororesin can be used as a coating layer, and the excellent adhesiveness with the heat-processed outer skin containing a polymerization type polyolefin elastomer can be obtained.

  Furthermore, a coating layer of a silane coupling agent can be interposed in at least a part between the mesh tube and the outer skin. When heat treatment is performed after coating the outer skin, the functional group generated by hydrolysis of the silane coupling agent is firmly bonded to the network tube, and the organic functional group of the silane coupling agent is chemically bonded to the polymerized polyolefin elastomer that forms the outer skin. This is because a reaction occurs and the joints are firmly joined. Such joining between the mesh tube and the outer shell has high resistance to a high-pressure steam atmosphere, so that joining is not impaired even when subjected to autoclave sterilization.

  The silane coupling agent may have at least one organic functional group selected from the group consisting of a vinyl group, a methacryl group, an epoxy group, an amino group, and a mercapto group. As described above, these organic functional groups cause a chemical reaction with the polymerized polyolefin elastomer by heat treatment, whereby the mesh tube and the outer skin are firmly bonded.

  According to the present invention, the outer skin is made of a polymerized polyolefin elastomer that is flexible and excellent in chemical resistance and hydrolysis resistance, and is subjected to heat treatment, so that the reticular tube and the outer skin, and the outer skin and after heating. It is possible to obtain an endoscope flexible tube that promotes adhesion with the formed coating layer and exhibits excellent resistance to disinfectant solution and autoclave sterilization.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a flexible tube for an endoscope according to a first embodiment of the present invention.

  As shown in FIG. 1, the endoscope flexible tube 1 includes a spiral tube 2, a mesh tube 3 covering the outer periphery of the spiral tube 2, an outer skin 4 covering the periphery of the mesh tube 3, and And a coat layer 5 covering the outer periphery of the outer skin 4.

  The spiral tube 2 is configured by spirally winding a thin plate having elasticity. Examples of the material constituting the thin plate having elasticity include stainless steel and copper alloy. The mesh tube 3 is configured by braiding a plurality of fine wires made of metal or nonmetal. As the material for the fine wire, stainless steel can be used for metal, and synthetic resin can be used for non-metal. Further, in order to improve the adhesion to the outer skin, there are cases where braiding is performed by mixing metallic and non-metallic thin wires.

  Covering the outer periphery of the mesh tube 3 with the outer skin 4 is performed by extruding a polymerization type polyolefin elastomer on the outer periphery of the mesh tube 3. The polymerization type polyolefin elastomer is produced by polymerizing an olefin monomer serving as a hard segment and then polymerizing an olefin monomer serving as a soft segment in the same polymerization reactor. The order of polymerization of the hard segment and the soft segment may be reversed.

  From the above points, the polymerizable polyolefin elastomer is distinguished from the non-polymerized polyolefin elastomer produced by mechanically dispersing and combining the hard segment and the soft segment with a kneader.

  The polymerized polyolefin elastomer constituting the outer skin 4 is excellent in durability against hydrolysis, flexibility and strength. As a specific example of such polymerized polyolefin elastomer, propylene is used as an olefin monomer as a hard segment. In the soft segment, ethylene / propylene rubber is used, and there is a specific name such as Zelas (trade name: manufactured by Mitsubishi Chemical Corporation). This polymerized polyolefin elastomer has a large amount of ethylene / propylene rubber introduced into propylene by direct reaction (polymerization), and is superior to the non-polymerized polyolefin elastomer in the following points.

  (1) Excellent flexibility.

  (2) Excellent heat resistance.

  (3) Strength is improved by about 30%.

  The film thickness of the outer skin 4 is preferably about 0.1 to 0.4 mm, more preferably about 0.15 to 0.4 mm.

  In order to finely adjust the flexibility of the flexible tube, two or more kinds of polymerizable polyolefin elastomers having different hardnesses may be mixed and used.

  After coating the outer skin 4 on the outer periphery of the mesh tube 3 and before forming the coat layer 5, the flexible tube is heated. The heating temperature is equal to or higher than the crystal melting temperature of the polymerizable polyolefin elastomer constituting the outer skin 4, and varies depending on the film thickness of the outer skin 4. Preferably, the temperature is equal to or higher than the crystal melting temperature of the elastomer and equal to or lower than the crystal melting temperature of the elastomer + 100 ° C. The heating time is preferably about 1 to 12 minutes.

  After the heat treatment, a coat layer 5 is coated on the outer periphery of the outer skin 4. By performing heat treatment at a temperature equal to or higher than the crystal melting temperature of the polymerizable polyolefin elastomer constituting the outer skin 4, the adhesion between the outer skin 4 and the coat layer 5 is greatly improved. As the coating layer 5, a fluororesin can be used.

  In the endoscope flexible tube 1 configured as described above, since the outer skin 4 is made of a polymerized polyolefin elastomer, it has excellent durability against disinfectant chemicals and autoclave sterilization.

  That is, the non-polymerization type polyolefin elastomer has a certain degree of good chemical resistance and heat resistance, but has poor flexibility and poor adhesion, and therefore constitutes the outer skin of a flexible tube for an endoscope. However, the polymerized polyolefin elastomer has an improvement in tensile strength and elongation at break of about 25% compared to the non-polymerized polyolefin elastomer. In particular, flexibility is given by a significant improvement in elongation, and it can exhibit excellent performance as an outer skin of a flexible tube for an endoscope even if different types of elastomers are not mixed as in the past. I can do it.

  In addition, the polymerized polyolefin elastomer has not only good chemical resistance but also resistance to hydrolysis, so even if it is subjected to autoclave sterilization in a high-pressure steam atmosphere, cracks and cracks of the outer skin do not occur, Excellent insertability can be maintained over a long period of time.

  By heating the polymerized polyolefin elastomer to a temperature higher than its crystal melting temperature, that is, near the melting point, the molecular motion of the low molecular weight component in the polyolefin elastomer is activated and transferred to the surface layer of the outer skin. As a result, it has been found through experiments that the adhesion between the mesh tube 3 and the outer skin 4 and between the outer skin 4 and the coat layer 5 is dramatically improved.

The present inventors made a flexible tube for an endoscope using a polymerized polyolefin elastomer as an outer skin, and conducted an experiment for improving adhesion by heating. That is, using Zeras (trade name: manufactured by Mitsubishi Chemical Corporation) as a polymerizable polyolefin elastomer, the heating temperature and the heating time were varied, and the adhesion between the mesh tube and the outer skin, and the outer skin and the coat layer was examined. The results are shown in Tables 1 and 2 below. Table 1 below shows the adhesion between the outer skin and the coat layer, and Table 2 below shows the results on the adhesion between the outer skin and the mesh tube. In the table, ◯ indicates good adhesion that can be used as an endoscope flexible tube, and x indicates inferior adhesion that cannot be used as an endoscope flexible tube.

  From Table 1 and Table 2 above, it can be seen that good adhesion can be obtained in a short time by heating to 150 ° C. or higher, which is the crystal melting temperature of the polymerizable polyolefin elastomer.

  Thus, in the endoscope flexible tube according to the present embodiment, the coat layer can be formed with good adhesion without applying a surface treatment of the outer skin or a primer.

  When the endoscope including the flexible tube for an endoscope according to the present embodiment is autoclaved in a steam atmosphere at 135 ° C. and 2 atm for 5 minutes, high-pressure steam penetrates into the endoscope insertion portion. As a result, the outer skin 4 was not deteriorated and the member accommodated in the endoscope insertion portion was not damaged. Therefore, it was possible to provide a safer endoscope in terms of bacterial infection.

  The present inventors manufactured an endoscope flexible tube using a polyester elastomer, a non-polymerized polyolefin elastomer, and a polymerized polyolefin elastomer as the outer skin, and comparatively observed the outer skin after being subjected to high-pressure steam sterilization using an autoclave. did. The results are shown in Table 3 below.

In addition, Hytrel (trade name: manufactured by Toray DuPont) is used as the polyester elastomer, Santoprene (product name: manufactured by AES Japan) is used as the non-polymerized polyolefin elastomer, and Zeras (product) is used as the polymerizable polyolefin elastomer. Name: manufactured by Mitsubishi Chemical Corporation). Further, in Table 3 below, a case where the outer shell was not cracked was marked as ◯, and a state where the outer shell was cracked and the watertight structure could not be maintained was marked as x.

  As is apparent from Table 3 above, when a polymerized polyolefin elastomer was used for the outer skin, no cracking of the outer skin was observed even 667 hours after the autoclave was charged. In contrast, when a polyester elastomer was used for the outer shell, cracking was observed in 60 hours after the autoclave was charged, and in a case where a non-polymerized polyolefin elastomer was used, cracking was observed in 73 hours.

  FIG. 2 shows an endoscope flexible tube according to a second embodiment of the present invention.

  As shown in FIG. 2, the endoscope flexible tube 10 includes a spiral tube 2, a mesh tube 3 that covers the outer periphery of the spiral tube 2 via a coupling agent coating layer 6, and the mesh tube 3. The outer skin 4 that covers the outer periphery of the outer skin 4, and the coat layer 5 that is applied to the surface of the outer skin 4.

  In the endoscope flexible tube 10 according to this embodiment configured as described above, a layer 6 in which a silane coupling agent is applied is formed between the mesh tube 3 and the outer skin 4. As the silane coupling agent, either a type diluted with water or a type diluted with a solvent may be used.

  In addition, when using the silane coupling agent of the type diluted with water, it is preferable that the dilution rate is 0.5 to 10%. When using the silane coupling agent of the type diluted with a solvent, the dilution rate is from the stock solution to It is preferably 10%.

  As the silane coupling agent, it is desirable to use an organic functional group having a vinyl group, a methacryl group, an epoxy group, an amino group, or a mercapto group.

  Conventionally, the mesh tube 3 and the outer skin 4 are joined via an adhesive. However, when subjected to autoclave sterilization in a high-pressure steam atmosphere, the adhesive is hydrolyzed and the outer skin 4 is removed from the mesh tube 3. There was a case of peeling. On the other hand, when a layer coated with a silane coupling agent is interposed between the reticular tube 3 and the outer skin 4 as in this embodiment, the hydrolysis of the silane coupling agent is performed by heat treatment after the outer skin 4 is coated. As a result, the organic functional group of the silane coupling agent undergoes a chemical reaction with the polymerized polyolefin elastomer constituting the outer skin 4 to be firmly bonded.

  Since the joining between the mesh tube 3 and the outer skin 4 has high resistance to a high-pressure steam atmosphere, the joining is impaired even when the endoscope flexible tube is subjected to autoclave sterilization. There is nothing.

  The endoscope provided with the flexible tube for an endoscope according to the present embodiment described above is subjected to autoclave sterilization for 5 minutes in a steam atmosphere of 135 ° C. and 2 atm similarly to the first embodiment. The high-pressure steam did not penetrate into the endoscope insertion portion, and the outer skin 4 was not deteriorated, and the joining between the mesh tube 3 and the outer skin 4 was not impaired. Therefore, it was possible to provide a safer endoscope in terms of bacterial infection.

  As described above, the example in which the outer skin is constituted by one type of polymerized polyolefin elastomer has been described. However, the present invention is not limited to this. A flexible tube for a mirror can be formed.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

(Appendix)
Appendix 1. In a flexible tube for an endoscope comprising a spiral tube, a mesh tube covered on the spiral tube, an outer skin coated on the outer periphery of the mesh tube, and a coat layer coated on the outer periphery of the outer skin, the outer skin is A flexible tube for an endoscope, comprising a polymerized polyolefin elastomer, coated with the outer skin, heat-treated at a temperature equal to or higher than a crystal melting temperature of the polymerized polyolefin elastomer, and then coated with the coat layer.

  Appendix 2. The flexible tube for an endoscope according to appendix 1, wherein the outer skin includes a mixture of two or more kinds of polymerized polyolefin elastomers having different hardnesses.

  Appendix 3. The flexible polyolefin tube for an endoscope according to appendix 1, wherein the polymerized polyolefin elastomer is obtained by polymerizing a hard segment made of propylene and then polymerizing a soft segment made of ethylene / propylene rubber.

  Appendix 4. The flexible tube for an endoscope according to appendixes 1 to 3, wherein the thickness of the outer skin is 0.1 to 0.4 mm.

  Appendix 5. The flexible tube for an endoscope according to any one of appendices 1 to 4, wherein a coating layer of a silane coupling agent is interposed in at least a part between the mesh tube and the outer skin.

  Appendix 6. The flexible tube for an endoscope according to appendix 5, wherein the silane coupling agent has at least one organic functional group selected from the group consisting of a vinyl group, a methacryl group, an epoxy group, an amino group, and a mercapto group.

  Appendix 7. The flexible tube for an endoscope according to appendix 5 or 6, wherein the silane coupling agent is diluted with water or a solvent.

  Appendix 8. The flexible tube for an endoscope according to any one of appendices 1 to 7, wherein the outer tube is coated and then heat-treated at a temperature equal to or higher than a crystal melting temperature of the polymerizable polyolefin elastomer.

  Appendix 9. The flexible tube for an endoscope according to appendix 8, wherein the heat treatment temperature is a crystal melting temperature of the polymerized polyolefin elastomer + 100 ° C. or less.

  Appendix 10. A step of covering the spiral tube with a mesh tube, a step of coating the outer periphery of the mesh tube with a skin containing a polymerized polyolefin elastomer, a step of heat-treating at or above the crystal melting temperature of the polymerized polyolefin elastomer, and a periphery of the shell The manufacturing method of the flexible tube for endoscopes which comprises the process of coat | covering a coating layer.

Sectional drawing which shows the flexible tube for endoscopes which concerns on one Embodiment of this invention. Sectional drawing which shows the flexible tube for endoscopes which concerns on other embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,10 ... Flexible tube, 2 ... Spiral tube, 3 ... Reticulated tube, 4 ... Outer skin, 5 ... Coat layer, 6 ... Coupling agent application layer.

Claims (2)

A process of covering a spiral tube with a mesh tube,
Coating the outer circumference of the mesh tube with a sheath containing a polymerized polyolefin elastomer;
A method of manufacturing a flexible tube for an endoscope, comprising: a step of heat-treating at a temperature equal to or higher than a crystal melting temperature of the polymerizable polyolefin elastomer; and a step of coating a coat layer on an outer periphery of the outer skin.   The method of manufacturing a flexible tube for an endoscope according to claim 1, wherein the outer skin includes a mixture of two or more kinds of polymerized polyolefin elastomers having different hardnesses.

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