A method for making a double-layer fluororesin catheter and products and applications thereof

Abstract

The present application relates to the technical field of double-layer fluororesin catheter, in particular to a preparation method, product and application of double-layer fluororesin catheter. The preparation method of double-layer fluororesin catheter comprises the following steps: using fluororesin to prepare an inner tube and an outer tube, and sleeving the inner tube into the outer tube to obtain a sleeve; after blocking one end of the sleeve, placing the sleeve into a processing device to sequentially perform preheating, expansion and cooling to obtain a double-layer fluororesin catheter. The double-layer fluororesin catheter provided in the present application has good bonding effect, the inner layer has good lubricity, and the outer layer needs to have softness and no toxic side effects.

Description

Technical Field

[0001] This invention relates to the field of double-layer fluoropolymer catheter technology, specifically to a method for preparing a double-layer fluoropolymer catheter, as well as the product and its application. Background Technology

[0002] Endoscopes used in medical devices typically integrate multiple functions, including LED lights, water vapor tubes, and electronic cameras. However, endoscopes cannot be directly inserted into the human body; a forceps tube is required as the insertion channel. The inner layer of the forceps tube needs to contact instruments or other tubes, thus requiring reduced frictional resistance. The natural passages within the human body are winding, confined, and have delicate mucous membranes, necessitating a soft and non-toxic outer layer for the forceps tube. A single-layer forceps tube may not pass smoothly through these natural passages and is prone to bending, potentially leading to surgical failure or patient discomfort. Therefore, the layered structure of the forceps tube needs improvement, requiring reduced frictional resistance on the inner surface and a soft, non-toxic outer layer to better meet the demands of using medical devices in the complex environment of the human body.

[0003] Chinese patent publication number CN111449701A discloses a clamp tube, which includes a head, which is a multi-layered composite structure with at least three layers, disposed inside the end of an endoscope; a tail, which is a single-layered structure for connecting the endoscope handle; and a transition section disposed between the head and the tail, wherein the transition section is a multi-layered composite structure to solve the risks of easy breakage, flattening, and damage; however, it does not disclose a technical solution for the inner layer having good lubricity and the outer layer having softness and no toxic side effects.

[0004] Therefore, providing a double-layer fluoropolymer conduit with a multi-layer structure, where the inner layer has excellent lubricity, the outer layer is soft, has no toxic side effects, and has good bending performance is the main technical problem that needs to be solved. Summary of the Invention

[0005] To address the aforementioned technical problems, the first aspect of this invention provides a method for preparing a double-layered fluoropolymer conduit, comprising the following steps:

[0006] The inner and outer tubes are prepared using fluoropolymer resin, and the inner tube is inserted into the outer tube to obtain a sleeve.

[0007] After sealing one end of the sleeve, it is placed in the processing device for preheating, expansion and cooling in sequence to obtain a double-layer fluoropolymer conduit.

[0008] In one embodiment, the inner tube is placed in a plasma machine for surface treatment before use; the surface treatment process of the inner tube in the plasma machine includes: first, evacuating the vacuum, then filling with a nitrogen atmosphere at a nitrogen gas flow rate of 5 cm³. 3 The flow rate is 400W / min, and the processing time is 3 minutes after the nitrogen gas flow rate stabilizes. After the processing is completed, the inner tube is removed.

[0009] In one embodiment, one end of the sleeve can be sealed by knotting or clamping with a tool to achieve an airtight seal.

[0010] In one embodiment, the manufacturing process of the inner tube includes:

[0011] The inner tube is obtained by aging, preforming, extruding, sintering, and cooling PTFE powder.

[0012] In one embodiment, the manufacturing process of the inner tube includes:

[0013] S1. After mixing PTFE powder with additive oil, it is cured at 30°C. After curing, it is pre-formed under a pressure of 2~3MPa to remove air and form a cylindrical blank.

[0014] S2. The blank is placed in the mold in the extrusion equipment and then extruded. The extruded tubular material is volatilized and then enters the sintering furnace. The sintering temperature is 400~500℃. After sintering for 1.5-3 minutes and cooling, the inner tube is obtained.

[0015] The PTFE powder used in the inner tube was purchased from manufacturers including Daikin Fluorochemicals Japan, specifically PTFE F201.

[0016] In one embodiment, the manufacturing process of the outer tube includes:

[0017] The outer tube is obtained by aging, preforming, stretching and extruding, volatilizing, rapidly sintering and cooling PTFE powder; the outer tube is an expanded PTFE outer tube.

[0018] In one embodiment, the manufacturing process of the outer tube includes:

[0019] S1. After mixing PTFE powder with additive oil, it is cured at 30°C. After curing, it is pre-formed under a pressure of 2~3MPa to remove air and form a cylindrical blank.

[0020] S2. The blank is placed in the mold of the extrusion equipment and then extruded. The extruded tubular material is stretched by a traction machine while evaporating. The stretching temperature is 200~250℃ and the stretching speed is 1.5~3 times the extrusion line speed. After the two ends of the stretched tubular material are clamped, it is rapidly sintered at 350~400℃ for 0.5-1min and then cooled and shaped to obtain the outer tube.

[0021] In one embodiment, the extrusion line speed is 1-3 m / min.

[0022] In one embodiment, the extrusion line speed is 2 m / min.

[0023] The PTFE powder used for the outer tube was purchased from manufacturers including Daikin Fluorochemicals Japan, specifically PTFE F104.

[0024] In one embodiment, the inner diameter of the inner tube is 3.5-3.8 mm, and the outer diameter is 3.85-4.1 mm;

[0025] In one embodiment, the inner diameter of the outer tube is 4.2-4.6 mm, and the outer diameter is 5.0-6.2 mm.

[0026] In one embodiment, the inner diameter of the inner tube is 3.7 mm and the outer diameter is 4.0 mm.

[0027] In one embodiment, the inner diameter of the outer tube is 4.3 mm and the outer diameter is 5.8 mm.

[0028] In one embodiment, the preheating temperature is greater than or equal to 240°C; the preheating includes primary preheating and secondary preheating.

[0029] In one embodiment, the primary preheating temperature is 240-260°C.

[0030] In one embodiment, the primary preheating temperature includes, but is not limited to, 240°C, 241°C, 242°C, 243°C, 244°C, 245°C, 246°C, 247°C, 248°C, 249°C, 250°C, 251°C, 252°C, 253°C, 254°C, 255°C, 256°C, 257°C, 258°C, 259°C, and 260°C.

[0031] In one embodiment, the primary preheating temperature is 250°C.

[0032] In one embodiment, the secondary preheating temperature is 290-310°C.

[0033] In one embodiment, the secondary preheating temperature includes, but is not limited to, 290°C, 291°C, 292°C, 293°C, 294°C, 295°C, 296°C, 297°C, 298°C, 299°C, 300°C, 301°C, 302°C, 303°C, 304°C, 305°C, 306°C, 307°C, 308°C, 309°C, and 310°C.

[0034] In one embodiment, the secondary preheating temperature is 300°C.

[0035] In one embodiment, the expansion temperature is 335-345°C.

[0036] In one embodiment, the expansion temperature includes, but is not limited to, 335°C, 336°C, 337°C, 338°C, 339°C, 340°C, 241°C, 242°C, 243°C, 244°C, and 245°C.

[0037] In one embodiment, the expansion temperature is 340°C.

[0038] In one embodiment, the cooling temperature is 10-20°C.

[0039] In one embodiment, the cooling temperature includes, but is not limited to, 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, and 20°C.

[0040] In one embodiment, the cooling temperature is 15°C.

[0041] In one embodiment, the traction speed of the processing device is 0.15-0.25 m / min.

[0042] In one embodiment, the traction speed of the processing device includes, but is not limited to, 0.15 m / min, 0.16 m / min, 0.17 m / min, 0.18 m / min, 0.19 m / min, 0.20 m / min, 0.21 m / min, 0.22 m / min, 0.23 m / min, 0.24 m / min, and 0.25 m / min.

[0043] In one embodiment, the traction speed of the processing device is 0.20 m / min.

[0044] In one embodiment, after one end of the sleeve is sealed, the other end of the sleeve is connected to an inflation device. The other end of the sleeve must not leak air, and air is injected into the gap between the inner and outer tubes. The inflation pressure is 0.018-0.03 MPa.

[0045] In one embodiment, the inflation pressure includes, but is not limited to, 0.018 MPa, 0.019 MPa, 0.02 MPa, 0.021 MPa, 0.022 MPa, 0.023 MPa, 0.024 MPa, 0.025 MPa, 0.026 MPa, 0.027 MPa, 0.028 MPa, 0.029 MPa, and 0.03 MPa.

[0046] In one embodiment, the inflation pressure is 0.02 MPa.

[0047] To enhance the bonding effect between the inner and outer tubes, and given that the inner layer of the double-layer fluororesin conduit has excellent lubricity while the outer layer is soft, non-toxic, and possesses good bending properties, the inventors discovered during experiments that the inner tube can be placed in a plasma machine for surface treatment. This surface treatment process involves first evacuating the inner tube, then filling it with a nitrogen atmosphere at a flow rate of 5 cm³. 3 The processing time is 3 minutes after the nitrogen gas flow rate stabilizes, with an energy of 400W per minute. After processing, the inner tube is removed and then inserted into the outer tube to obtain a sleeve. One end of the sleeve is sealed and placed in the processing device for preheating, expansion, and cooling to obtain a double-layer fluoropolymer conduit. The preheating temperature is greater than or equal to 240℃. The preheating includes primary and secondary preheating. The primary preheating temperature is 240-260℃. The secondary preheating temperature is 290-310℃. The expansion temperature is 335-345℃. The traction speed of the processing device is 0.15-0.25 m / min. The inflation pressure is 0.018-0.03 MPa. The cooling temperature is 10-20℃. By adopting the above preheating, expansion, and cooling methods, the process is completed. The expansion of internal air pressure and the slight melting effect of the high-temperature zone can bond the inner and outer tubes together, resulting in a double-layered fluoropolymer conduit with good bonding properties. However, the inventors discovered that when the secondary preheating and expansion temperature are low, the inner and outer tubes of the double-layered fluoropolymer conduit may not be bonded and may delaminate. When the inflation pressure is low, the bonding effect between the inner and outer tubes is not strong enough, and the peeling force is relatively low. When the traction speed is too fast, the welding time is insufficient, resulting in a weak bond between the inner and outer tubes. When the expansion temperature is too high and the traction speed is too fast, the inner and outer tubes may be over-sintered, resulting in a hard tube with poor bending performance, a transparent appearance, and loss of expanded polytetrafluoroethylene (ePTFE) properties.

[0048] A second aspect of the present invention provides a double-layered fluoropolymer conduit, which is prepared by the aforementioned method for preparing a double-layered fluoropolymer conduit.

[0049] The double-layer fluoropolymer conduit includes an inner tube and an outer tube, wherein the inner tube is a PTFE inner tube and the outer tube is an expanded PTFE outer tube.

[0050] A third aspect of the present invention provides an application of a double-layered fluoropolymer catheter in the field of medical device technology.

[0051] Beneficial effects

[0052] 1. The double-layer fluoropolymer conduit provided in this application has good bonding effect, with excellent lubricity of the inner layer and softness and no toxic side effects of the outer layer.

[0053] 2. The preparation method of the double-layer fluoropolymer conduit provided in this application can avoid the inner and outer tubes of the double-layer fluoropolymer conduit from being unbonded or delaminated.

[0054] 3. The preparation method of the double-layer fluororesin conduit provided in this application can avoid the problems of insufficient bonding between the inner and outer tubes of the double-layer fluororesin conduit and low tear strength.

[0055] 4. The preparation method of the double-layer fluororesin conduit provided in this application can avoid the problem of weak bonding between the inner and outer tubes of the double-layer fluororesin conduit.

[0056] 5. The preparation method of the double-layer fluororesin conduit provided in this application can improve the resilience of the double-layer fluororesin conduit and give it good bending performance. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the preparation process of the double-layer fluoropolymer conduit provided in Example 1.

[0058] Figure 2 This is a schematic diagram of the structure of the double-layer fluoropolymer conduit provided in Example 1.

[0059] Figure 3 The diagram shows the unbonded and delaminated states of the double-layered fluoropolymer conduit provided for Comparative Example 1.

[0060] Figure 4 The diagram shows the unbonded and delaminated states of the double-layered fluoropolymer conduit provided for Comparative Example 1.

[0061] Figure 5 The diagram shows the change in peel force during the peel force test of the double-layer fluoropolymer conduit provided in Example 1.

[0062] Figure 6 This is the minimum bending diameter test method.

[0063] Figure 7 This is a method for testing resilience.

[0064] Figure 8 The outer tube of Example 1 is in a white state.

[0065] Figure 9 The outer tube of Comparative Example 4 is in a transparent state.

[0066] Figure 1 In the middle: 01. Pipe delivery reel (including air pressure); 02. Sleeve; 03. Primary preheating zone; 04. Secondary preheating zone; 05. Expansion zone; 06. Cooling zone; 07. Traction wheel of processing equipment; 08. Finished pipe receiving zone.

[0067] Figure 2 In Chinese: 101, outer tube; 102, inner tube. Detailed Implementation

[0068] Example 1

[0069] The first aspect of this embodiment provides a method for preparing a double-layered fluoropolymer conduit, comprising the following steps:

[0070] The inner and outer tubes are prepared using fluoropolymer resin, and the inner tube is inserted into the outer tube to obtain a sleeve.

[0071] After sealing one end of the sleeve, it is placed in the processing device for preheating, expansion and cooling in sequence to obtain a double-layer fluoropolymer conduit.

[0072] Figure 1 This is a schematic diagram illustrating the preparation process of the double-layer fluoropolymer conduit provided in this embodiment.

[0073] The inner tube is placed in a plasma machine for surface treatment before use. The surface treatment process of the inner tube in the plasma machine includes first evacuating the vacuum, then filling it with a nitrogen atmosphere at a flow rate of 5 cm³. 3 The plasma energy is 400W, and the treatment time is 3 minutes after the nitrogen gas flow rate stabilizes. After the treatment is completed, the inner tube is removed.

[0074] By sealing one end of the sleeve, an airtight seal is achieved.

[0075] The manufacturing process of the inner tube includes:

[0076] S1. By mass percentage, 75wt% of PTFE powder and 25wt% of auxiliary oil are mixed and cured at 30°C. After curing, the mixture is pre-formed under 2MPa pressure to remove air and form a cylindrical blank.

[0077] S2. The billet is placed in the mold in the extrusion equipment and then extruded. The extruded tubular material is volatilized and then enters the sintering furnace. The sintering temperature is 420℃ and the sintering time is 2min. After cooling, an inner tube is obtained. The cooling temperature is 25℃. The inner tube is a PTFE tube.

[0078] The PTFE powder used in the inner tube was purchased from Daikin Fluorochemicals of Japan, model number F201.

[0079] The auxiliary oil used in the inner tube was purchased from ExxonMobil G type.

[0080] The inner diameter of the inner tube is 3.7 mm and the outer diameter is 4.0 mm.

[0081] The manufacturing process of the outer tube includes:

[0082] S1. By mass percentage, 75wt% of PTFE powder and 25wt% of auxiliary oil are mixed and cured at 30°C. After curing, the mixture is pre-formed under 2MPa pressure to remove air and form a cylindrical blank.

[0083] S2. The billet is placed in the die inside the extrusion equipment and extruded. The extruded tubular material is stretched by a traction machine while evaporating. The stretching temperature is 200℃, the stretching speed is twice the extrusion line speed, and the extrusion line speed is 2m / min. After stretching, the two ends of the tubular material are clamped and rapidly sintered at 350℃ for 1 minute, and then cooled and shaped to obtain the outer tube. The cooling temperature is 25℃. The outer tube is an expanded PTFE outer tube.

[0084] The PTFE powder used for the outer tube was purchased from Daikin Fluorochemicals, Japan, specifically model PTFE F104.

[0085] The auxiliary oil used in the outer pipe was purchased from ExxonMobil G type.

[0086] The inner diameter of the outer tube is 4.3 mm, and the outer diameter is 5.8 mm.

[0087] The preheating includes primary preheating and secondary preheating.

[0088] The primary preheating temperature is 250℃.

[0089] The secondary preheating temperature is 300℃.

[0090] The expansion temperature is 340°C.

[0091] The cooling temperature is 15°C.

[0092] The traction speed of the processing device is 0.20 m / min.

[0093] After one end of the sleeve is sealed, the other end of the sleeve is connected to the inflation device. The other end of the sleeve must not leak air. Air is injected into the gap between the inner and outer tubes. The inflation pressure is 0.02 MPa.

[0094] The second aspect of this embodiment provides a double-layered fluoropolymer conduit, which is prepared by the aforementioned method for preparing a double-layered fluoropolymer conduit.

[0095] The double-layer fluoropolymer conduit includes an inner tube and an outer tube, wherein the inner tube is a PTFE tube and the outer tube is an expanded PTFE outer tube.

[0096] Figure 2 A schematic diagram of a double-layered fluoropolymer conduit is provided.

[0097] The third aspect of this embodiment provides an application of a double-layered fluoropolymer catheter in the field of medical device technology.

[0098] Comparative Example 1

[0099] This comparative example provides a method for preparing a double-layer fluoropolymer conduit. The specific implementation method is the same as in Example 1, except that the secondary preheating temperature is 280°C and the expansion temperature is 330°C.

[0100] This comparative example provides a double-layered fluoropolymer conduit, which is prepared by the aforementioned method for preparing a double-layered fluoropolymer conduit.

[0101] The double-layered fluororesin conduit obtained in this comparative example exhibits an unbonded inner and outer tube, showing a delamination state, as shown in the figure. Figure 3 and Figure 4 .

[0102] Comparative Example 2

[0103] This comparative example provides a method for preparing a double-layer fluoropolymer conduit. The specific implementation method is the same as in Example 1, except that after one end of the sleeve is sealed, the other end of the sleeve is connected to an inflation device. The other end of the sleeve must not leak air. Air is injected into the gap between the inner and outer tubes, and the inflation pressure is 0.01 MPa.

[0104] This comparative example provides a double-layered fluoropolymer conduit, which is prepared by the aforementioned method for preparing a double-layered fluoropolymer conduit.

[0105] Comparative Example 3

[0106] This comparative example provides a method for preparing a double-layer fluoropolymer conduit. The specific implementation method is the same as in Example 1, except that the traction speed of the processing device is 0.40 m / min.

[0107] This comparative example provides a double-layered fluoropolymer conduit, which is prepared by the aforementioned method for preparing a double-layered fluoropolymer conduit.

[0108] Comparative Example 4

[0109] This comparative example provides a method for preparing a double-layer fluoropolymer conduit. The specific implementation method is the same as that in Example 1, except that the expansion temperature is 380℃ and the traction speed of the processing device is 0.40m / min.

[0110] This comparative example provides a double-layered fluoropolymer conduit, which is prepared by the aforementioned method for preparing a double-layered fluoropolymer conduit.

[0111] Performance testing

[0112] 1. Peeling performance test:

[0113] The double-layer fluoropolymer conduits provided in Example 1 and Comparative Examples 1-4 were tested for peel force between the inner and outer tubes according to GB / T 8808-1988 "Peel Test Method for Flexible Composite Plastic Materials". The test speed was 50 mm / min, and the test results are shown in Table 1.

[0114] The peel force change during the peel force test of the double-layer fluoropolymer catheter provided in Example 1 is shown in the figure. Figure 5 .

[0115] 2. Minimum bending diameter test:

[0116] A certain length of the double-layer fluoropolymer conduit provided in Example 1 and Comparative Examples 1-4 was placed into a fixture. One end of the fixture was fixed, and the other end was moved inward until a crease appeared at the top of the conduit. The movement was then stopped, and the minimum bending radius of the double-layer fluoropolymer conduit was recorded. The test method is described in [link to test method]. Figure 6 The test results are shown in Table 1.

[0117] 3. Resilience test:

[0118] Take a certain length of the double-layered fluoropolymer conduit provided in Example 1 and Comparative Examples 1-4 respectively and place it in a tooling. Bend the double-layered fluoropolymer conduit to 180° and then release the movable end. Observe the instantaneous rebound angle of the double-layered fluoropolymer conduit. The test method is as follows: Figure 7 The test results are shown in Table 1.

[0119] 4. Color test of outer tube:

[0120] The color of the outer tube of the double-layer fluoropolymer conduit provided in Example 1 and Comparative Examples 1-4 was recorded, and the results are shown in Table 1.

[0121] The outer tube of the double-layered fluoropolymer conduit provided in Example 1 is white. (See the image for the white state.) Figure 8 .

[0122] The outer tube of the double-layered fluoropolymer conduit provided in Comparative Example 4 is transparent. (See attached image for transparency details.) Figure 9 .

[0123] Table 1

[0124]

[0125] In Table 1, " / " indicates that it cannot be measured.

[0126] The double-layered fluoropolymer conduit provided in Comparative Example 1 showed that the inner and outer tubes were not bonded together, exhibiting a delamination state, making it impossible to measure the tear force.

[0127] The double-layer fluoropolymer conduit provided in Comparative Example 4 showed that the inner and outer tubes were firmly bonded together, and the interface between the inner and outer tubes was completely melted, making it impossible to measure the tear force.

[0128] In Comparative Example 1, with low secondary preheating and low expansion temperature, the inner and outer tubes of the resulting double-layer fluoropolymer conduit exhibited unbonded and delamination. In Comparative Example 2, with low inflation pressure, the bonding between the inner and outer tubes was insufficient, resulting in low tear strength. In Comparative Example 3, excessively high traction speed led to insufficient welding time, resulting in weak bonding between the inner and outer tubes. In Comparative Example 4, with excessively high expansion temperature and excessively high traction speed, the inner and outer tubes exhibited over-sintering, resulting in a hard tube with poor bending performance, a transparent appearance, and a loss of expanded polytetrafluoroethylene (ePTFE) properties.

Claims

1. A method for preparing a double-layered fluoropolymer conduit, characterized in that, Includes the following steps: The inner and outer tubes are prepared using fluoropolymer resin, and the inner tube is inserted into the outer tube to obtain a sleeve. After sealing one end of the sleeve, it is placed in the processing device and preheated, expanded and cooled in sequence to obtain a double-layer fluoropolymer conduit. The preheating temperature is greater than or equal to 240°C; the preheating includes primary preheating and secondary preheating. The secondary preheating temperature is 290-310℃; The expansion temperature is 335-345℃; The traction speed of the processing device is 0.15-0.25 m / min; After one end of the sleeve is sealed, the other end of the sleeve is connected to the inflation device to inflate the gap between the inner and outer tubes. The inflation pressure is 0.018-0.03 MPa. The inner tube is a PTFE inner tube; The outer tube is an expanded PTFE outer tube.

2. The method for preparing the double-layer fluoropolymer conduit as described in claim 1, characterized in that, The primary preheating temperature is 240-260℃.

3. The method for preparing the double-layer fluoropolymer conduit as described in claim 1, characterized in that, The cooling temperature is 10-20℃.

4. A double-layered fluoropolymer conduit, characterized in that, It is prepared by the method for preparing double-layer fluoropolymer conduit as described in any one of claims 1-3.

5. An application of the double-layer fluoropolymer conduit according to claim 4, characterized in that, The double-layered fluoropolymer catheter is used in the field of medical device technology.

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