A method for producing an e-PTFE membrane tube and an e-PTFE membrane tube

Abstract

The application discloses a preparation method of an e-PTFE membrane tube, comprising the following steps: arranging and stacking at least two e-PTFE membranes with different fiber directions on a tooling mold in a staggered manner according to the respective fiber directions to obtain an e-PTFE membrane winding body; heating and heat-insulating the e-PTFE membrane winding body, and obtaining a formed e-PTFE membrane winding body after cooling; and disassembling the formed e-PTFE membrane winding body from the tooling mold to obtain the e-PTFE membrane tube. The application further discloses the e-PTFE membrane tube prepared by the method. The e-PTFE membrane tube prepared by the preparation method has anisotropic high tensile strength and high suture tensile force, meets the performance requirements of the e-PTFE membrane tube, and reduces the production cost and process difficulty, and can meet the requirements of e-PTFE membrane tubes with different thicknesses.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a method for preparing an e-PTFE membrane tube and the e-PTFE membrane tube itself. Background Technology

[0002] Expanded polytetrafluoroethylene (e-PTFE) is a novel polymer material, originally produced through special processing methods such as stretching polytetrafluoroethylene (PTFE). Stretching PTFE produces numerous microfibers and segmented structures, which form countless pores, giving e-PTFE superior elasticity and flexibility compared to PTFE. Furthermore, due to its excellent biocompatibility, physicochemical stability, non-toxicity, non-carcinogenicity, and non-allergenic properties, e-PTFE has been widely used in industrial, military, and medical fields since its introduction in the 1960s.

[0003] For example, in clinical medical use, e-PTFE can be used as an artificial blood vessel in the form of a membrane tube to treat aortic aneurysms, aortic stenosis, and superior and inferior vena cava resection and replacement. It can also be used in the intima layer and sheath splicing of various multilayer composite sheaths. These sheaths are widely used in various transcatheter interventional procedures.

[0004] However, the e-PTFE membrane tubes currently used in clinical practice have certain shortcomings:

[0005] (1) Due to the low surface coefficient of e-PTFE, it is difficult to use adhesives to bond and fix it. e-PTFE membrane tubes are usually made by directly rolling the e-PTFE membrane on a rod of uniform diameter to form a round tube. This method is difficult to meet the preparation requirements of e-PTFE membrane tubes of different thicknesses.

[0006] (2) Uniaxial e-PTFE membrane tubes have a single fiber orientation, resulting in lower tensile strength perpendicular to the fiber orientation and making them prone to cracking; biaxial e-PTFE membrane tubes, despite having anisotropic fiber orientation and higher overall tensile strength, have higher production costs and more complex manufacturing processes.

[0007] (3) Since e-PTFE membrane tubes require certain support strength, elasticity, anisotropy and resistance to suture tension, e-PTFE membrane tubes made of single-layer membrane materials usually cannot meet these requirements. Summary of the Invention

[0008] In order to overcome at least one of the defects described in the prior art, the present invention provides a method for preparing an e-PTFE membrane tube and an e-PTFE membrane tube, which can meet the preparation requirements of e-PTFE membrane tubes of different thicknesses, reduce the production and manufacturing cost and process difficulty of e-PTFE membrane tubes, and the prepared e-PTFE membrane tube has high support strength and elasticity, anisotropic high tensile strength and high suture tensile strength.

[0009] The technical solution adopted by this invention to solve its problem is:

[0010] In a first aspect, the present invention provides a method for preparing an e-PTFE membrane tube, comprising the following steps:

[0011] At least two layers of e-PTFE membranes with different fiber orientations are staggered according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding.

[0012] The e-PTFE membrane roll is heated and kept at a certain temperature, and then cooled to obtain the formed e-PTFE membrane roll.

[0013] The formed e-PTFE membrane roll is removed from the tooling mold to obtain the e-PTFE membrane tube.

[0014] Secondly, the present invention also provides an e-PTFE membrane tube, which is manufactured using the above-mentioned method for preparing an e-PTFE membrane tube.

[0015] In summary, the method for preparing an e-PTFE membrane tube and the e-PTFE membrane tube provided by this invention have the following technical advantages compared with the prior art:

[0016] This invention prepares e-PTFE membrane tubes by layering and winding multiple layers of e-PTFE membranes with different fiber orientations. These tubes exhibit high anisotropic tensile strength and high suture tensile strength, meeting the performance requirements of e-PTFE membrane tubes. Furthermore, by using uniaxially stretched finished e-PTFE membranes for layering and winding, compared to directly and simultaneously performing biaxial stretching of e-PTFE membranes, production costs and manufacturing process difficulty are significantly reduced. Simultaneously, e-PTFE membrane tubes of different thicknesses can be prepared by layering and winding multiple layers of e-PTFE membranes, adapting to the needs of e-PTFE membrane tubes of varying thicknesses. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of two layers of e-PTFE membrane stacked and wound on a tooling mold in one embodiment of the present invention;

[0018] Figure 2This is a schematic diagram of the structure of two layers of e-PTFE membrane and adhesive layer stacked and wound on a tooling mold in another embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the structure of two layers of e-PTFE membrane and heat-resistant material layer stacked and wound on a tooling mold in another embodiment of the present invention.

[0020] Icons: 1. e-PTFE membrane with fiber orientation at 90° to the tooling mold axis; 2. e-PTFE membrane with fiber orientation at 0° to the tooling mold axis; 3. Adhesive layer; 4. Heat-resistant material layer; 5. Dumbbell-shaped liner; 51. Mandrel; 52. Connecting end block; 6. Dumbbell-shaped mold. Detailed Implementation

[0021] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0022] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0024] Orientation definition: In the field of interventional medical devices, proximal refers to the end closer to the operator, while distal refers to the end farther from the operator; medial refers to the side closer to the central axis, while lateral refers to the side farther from the central axis.

[0025] Example 1

[0026] To address the need for preparing e-PTFE membrane tubes and to ensure that the prepared e-PTFE membrane tubes possess anisotropic high tensile strength and high suture tensile strength, Embodiment 1 of this invention provides a method for preparing e-PTFE membrane tubes, comprising the following steps:

[0027] S1. At least two layers of e-PTFE membranes with different fiber orientations are staggered according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0028] S2. Heat and keep the e-PTFE membrane roll at a certain temperature, and then cool it to obtain the formed e-PTFE membrane roll.

[0029] S3. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0030] This invention obtains an anisotropic e-PTFE membrane tube with high tensile strength and high suture tensile strength by sintering and fixing at least two layers of e-PTFE membranes with different fiber orientations together. Specifically, in step S1, at least two layers of e-PTFE membranes with different fiber orientations are stacked together, and their respective fiber orientations are misaligned by 45°-90°. This misalignment allows the prepared e-PTFE membrane tube to have anisotropic high tensile strength and high suture tensile strength. Further specifically, in step S2, the multilayer e-PTFE membranes are sintered and fixed by heating and then cooled to obtain a multilayer e-PTFE membrane roll. Further specifically, in step S3, the e-PTFE membrane roll is disassembled from the tooling mold to obtain the e-PTFE membrane tube.

[0031] In the preparation method of this embodiment, the number of e-PTFE membrane layers with different fiber orientations ranges from 2 to 8. When the thickness of the e-PTFE membrane remains constant, to obtain a thicker e-PTFE membrane tube, the overall tensile strength and suture tensile strength can be further improved by increasing the number of e-PTFE membrane layers, for example, by using 3-8 layers of e-PTFE membrane to wind and prepare a thicker e-PTFE membrane tube.

[0032] The heating temperature range is 300-385℃, and the heating time range is 5-60 minutes. Heating refers to placing the e-PTFE membrane roll and the tooling mold together in an oven preheated to the heating temperature for 5-60 minutes. The purpose of heating is to melt the multiple layers of e-PTFE membrane with different fiber orientations.

[0033] The holding temperature is the same as the heating temperature, and the holding time ranges from 5 to 20 minutes. Holding refers to maintaining the oven temperature constant after the preset heating time has been reached, ensuring the e-PTFE membrane roll and tooling mold remain at the heating temperature. The purpose of holding is to sinter and fix the molten multilayer e-PTFE membrane together.

[0034] After cooling, the sintered and fixed multilayer e-PTFE membrane is shaped to conform to the outer surface of the tooling mold, for example, a uniform cylindrical shape. Cooling methods can include common methods such as room temperature cooling or alcohol cooling, which will not be elaborated upon here.

[0035] The e-PTFE membrane tube prepared in this embodiment was observed under a scanning electron microscope (SEM), and its fiber orientation exhibited anisotropy. Tensile testing on a tensile testing machine showed that the overall tensile strength of the multilayer membrane tube, which was stacked and wound, was significantly higher than that of a single-layer uniaxially stretched finished e-PTFE membrane. Furthermore, because a uniaxially stretched finished e-PTFE membrane was used for stacking and winding, compared to directly and simultaneously biaxially stretched e-PTFE membranes, production costs and manufacturing process difficulty were greatly reduced.

[0036] Example 2

[0037] Embodiment 2 of the present invention provides a method for preparing an e-PTFE membrane tube, comprising the following steps:

[0038] S1. Two layers of e-PTFE membranes with different fiber orientations are staggered by 90° according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0039] Optionally, see Figure 1 The fiber orientation of the first layer of e-PTFE membrane wound on the tooling mold can be 90° to the axis of the tooling mold (i.e., Figure 1 If the first layer of e-PTFE membrane has a fiber orientation at 90° to the axis of the tooling mold, then the second layer of e-PTFE membrane has a fiber orientation at 0° to the axis of the tooling mold (i.e., ...). Figure 1 2) An e-PTFE membrane with fiber orientation at 0° to the tooling mold axis;

[0040] S2. Heat the e-PTFE membrane roll to 300℃ and keep it at 300℃ for 5 minutes. After cooling, the formed e-PTFE membrane roll is obtained.

[0041] S3. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0042] Example 3

[0043] Embodiment 3 of the present invention provides a method for preparing an e-PTFE membrane tube, comprising the following steps:

[0044] S1. Five layers of e-PTFE membrane with different fiber orientations are arranged with a 60° offset according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0045] S2. Heat the e-PTFE membrane roll to 345℃ and keep it at 345℃ for 12 minutes. After cooling, the formed e-PTFE membrane roll is obtained.

[0046] S3. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0047] Example 4

[0048] Example 4 of this invention provides a method for preparing an e-PTFE membrane tube, comprising the following steps:

[0049] S1. Eight layers of e-PTFE membrane with different fiber orientations are staggered by 45° according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0050] S2. Heat the e-PTFE membrane roll to 385℃ and keep it at 385℃ for 20 minutes. After cooling, the formed e-PTFE membrane roll is obtained.

[0051] S3. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0052] Example 5

[0053] To improve the adhesion between adjacent e-PTFE membrane layers and increase the strength of the e-PTFE membrane tube, Embodiment 5 of the present invention provides a method for preparing an e-PTFE membrane tube, which involves adding an adhesive layer 3 between adjacent e-PTFE membrane layers, including the following steps:

[0054] S1. At least two layers of e-PTFE membranes with different fiber orientations are staggered according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0055] S2. An adhesive layer 3 is provided between two adjacent e-PTFE membranes with different fiber orientations;

[0056] S3. Heat and keep the e-PTFE membrane roll at a certain temperature, and then cool it to obtain the formed e-PTFE membrane roll.

[0057] S4. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0058] It is understood that S1, S2, S3, and S4 are used only for ease of description and are not intended to limit the order of steps in the preparation method of the present invention. For example, in the preparation method of this embodiment, S1 can be described as: at least two layers of e-PTFE membranes with different fiber orientations are staggered according to their respective fiber orientations and stacked and wound on a tooling mold, and an adhesive layer 3 is provided between two adjacent layers of e-PTFE membranes with different fiber orientations to obtain an e-PTFE membrane winding. Specifically, in this embodiment, if only two layers of e-PTFE membrane with different fiber orientations are used, the adhesive layer 3 is disposed between the first and second e-PTFE membrane layers. The preparation method steps in this embodiment are as follows: the first e-PTFE membrane is wound onto a tooling mold, the adhesive layer 3 is applied to the outside of the first e-PTFE membrane, and the second e-PTFE membrane is wound onto the outside of the adhesive layer 3 to obtain an e-PTFE membrane winding body with the adhesive layer 3. The e-PTFE membrane winding body with the adhesive layer 3 is heated and kept warm, and after cooling, a formed e-PTFE membrane winding body is obtained. The formed e-PTFE membrane winding body is removed from the tooling mold to obtain an e-PTFE membrane tube.

[0059] In this embodiment, by setting an adhesive layer 3 between two adjacent e-PTFE membrane layers, the adhesive layer 3 will melt accordingly during the preparation process. Therefore, compared with the direct bonding of the prior art, it can still effectively improve the firmness between the two adjacent e-PTFE membrane layers, thereby improving the support strength of the prepared e-PTFE membrane tube. It is understood that, depending on the thickness and performance of the e-PTFE membrane tube to be prepared, different numbers of e-PTFE membrane layers can be selected, and one or more adhesive layers 3 can be set accordingly.

[0060] The adhesive layer 3 has a lower melting point than the e-PTFE. Therefore, when the two e-PTFE membranes sandwiching the adhesive layer 3 are heated together, the adhesive will reach its melting point and melt first because its melting point is lower than that of the e-PTFE. At this point, the e-PTFE membrane has not yet reached its melting point and therefore does not melt. Furthermore, since the e-PTFE membranes on both sides of the adhesive layer 3 have a porous structure, the molten adhesive will flow to the pore surfaces of the e-PTFE membranes on both sides, and may even completely fill the pores. After the e-PTFE membrane roll cools down, the two e-PTFE membranes on both sides can be further fixed and bonded together.

[0061] The adhesive layer 3 includes at least one adhesive selected from at least one of polytetrafluoroethylene, polyether block polytetrafluoroethylene, or polypropylene.

[0062] The thickness of the adhesive layer 3 ranges from 0.02 to 0.05 mm, which achieves the purpose of bonding the two adjacent e-PTFE membranes while avoiding the excessive time required for heating and melting of an excessively thick adhesive layer 3, and the impact of an excessively thick adhesive layer 3 on the supporting strength and elasticity of the prepared e-PTFE membrane tube.

[0063] The heating temperature range is 200-360℃. The holding temperature is the same as the heating temperature, and the holding time ranges from 4 to 15 minutes. Since an adhesive layer 3 is added in this embodiment, and the melting point of the adhesive is lower than that of e-PTFE, the required heating temperature is lower than that in Examples 1-4, and the required holding time is also reduced accordingly, thus further reducing production costs.

[0064] Example 6

[0065] Embodiment 6 of the present invention provides a method for preparing an e-PTFE membrane tube, comprising the following steps:

[0066] S1. Two layers of e-PTFE membranes with different fiber orientations are staggered by 90° according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0067] Optionally, see Figure 2 The fiber orientation of the first layer of e-PTFE membrane wound on the mold can be 90° to the axis of the tooling mold (i.e., Figure 2 If the first layer of e-PTFE membrane has a fiber orientation at 90° to the axis of the tooling mold, then the second layer of e-PTFE membrane has a fiber orientation at 0° to the axis of the tooling mold (i.e., ...). Figure 2 2) An e-PTFE membrane with fiber orientation at 0° to the tooling mold axis;

[0068] S2. An adhesive layer 3 is provided between two adjacent e-PTFE membranes with different fiber orientations, and the adhesive layer 3 covers the outside of the first e-PTFE membrane.

[0069] The adhesive layer 3 is made of polytetrafluoroethylene.

[0070] The thickness of the adhesive layer 3 is 0.02 mm;

[0071] S3. Heat the e-PTFE membrane roll to 200℃ and keep it at 200℃ for 4 minutes. After cooling, the formed e-PTFE membrane roll is obtained.

[0072] S4. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0073] Example 7

[0074] Embodiment 7 of the present invention provides a method for preparing an e-PTFE membrane tube, comprising the following steps:

[0075] S1. Five layers of e-PTFE membrane with different fiber orientations are arranged with a 60° offset according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0076] S2. An adhesive layer 3 is provided between two adjacent e-PTFE membranes with different fiber orientations, and the adhesive layer 3 covers the outside of the first and third e-PTFE membranes.

[0077] The adhesive is polyether-block polytetrafluoroethylene;

[0078] The thickness of adhesive layer 3 is 0.035 mm;

[0079] S3. Heat the e-PTFE membrane roll to 280℃ and keep it at 280℃ for 10 minutes. After cooling, the formed e-PTFE membrane roll is obtained.

[0080] S4. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0081] Example 8

[0082] Example 8 of this invention provides a method for preparing an e-PTFE membrane tube, comprising the following steps:

[0083] S1. Eight layers of e-PTFE membrane with different fiber orientations are staggered by 45° according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0084] S2. An adhesive layer 3 is provided between each pair of adjacent e-PTFE membranes with different fiber orientations, and the adhesive layer 3 covers the outside of the first 7 e-PTFE membranes.

[0085] The adhesive layer 3 is made of polypropylene.

[0086] The thickness of adhesive layer 3 is 0.05 mm.

[0087] S3. Heat the e-PTFE membrane roll to 360°C and keep it at 360°C for 15 minutes. After cooling, the formed e-PTFE membrane roll is obtained.

[0088] S4. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0089] Example 9

[0090] To improve the heat resistance of e-PTFE membrane tubes, Embodiment 9 of the present invention provides a method for preparing e-PTFE membrane tubes, which involves adding a heat-resistant material layer 4 between two adjacent e-PTFE membrane layers, including the following steps:

[0091] S1. At least two layers of e-PTFE membranes with different fiber orientations are staggered according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0092] S2. A heat-resistant material layer 4 is provided between two adjacent e-PTFE membranes with different fiber orientations;

[0093] S3. Heat and keep the e-PTFE membrane roll at a certain temperature, and then cool it to obtain the formed e-PTFE membrane roll.

[0094] S4. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0095] It is understood that S1, S2, S3, and S4 are used only for ease of description and are not intended to limit the order of steps in the preparation method of the present invention. For example, in the preparation method of this embodiment, S1 can be described as follows: at least two layers of e-PTFE membranes with different fiber orientations are staggered according to their respective fiber orientations and stacked and wound on a tooling mold, and a heat-resistant material layer 4 is provided between two adjacent layers of e-PTFE membranes with different fiber orientations to obtain an e-PTFE membrane winding body. Specifically, in this embodiment, if only two layers of e-PTFE membrane with different fiber orientations are used, the heat-resistant material layer 4 is disposed between the first and second e-PTFE membranes. The preparation method steps in this embodiment are as follows: the first e-PTFE membrane is wound onto a tooling mold, the heat-resistant material layer 4 is applied to the outside of the first e-PTFE membrane, and the second e-PTFE membrane is wound onto the outside of the heat-resistant material layer 4 to obtain an e-PTFE membrane winding body with the heat-resistant material layer 4. The e-PTFE membrane winding body with the heat-resistant material layer 4 is heated and kept at a certain temperature. After cooling, a formed e-PTFE membrane winding body is obtained. The formed e-PTFE membrane winding body is removed from the tooling mold to obtain an e-PTFE membrane tube.

[0096] In this embodiment, by setting a heat-resistant material layer 4 between two adjacent e-PTFE membrane layers, the heat resistance of the e-PTFE membrane tube can be effectively improved. It is understood that, depending on the required thickness and performance of the e-PTFE membrane tube, different numbers of e-PTFE membrane layers can be selected, and one or more heat-resistant material layers 4 can be set accordingly.

[0097] The melting point of the heat-resistant material is lower than that of e-PTFE. Therefore, when the two e-PTFE membranes sandwiching the heat-resistant material layer 4 are heated together, the heat-resistant material layer 4 will melt first because its melting point is lower than that of e-PTFE. Furthermore, the e-PTFE membranes on both sides of the heat-resistant material layer 4 have a porous structure, allowing the molten heat-resistant material to flow to the pore surfaces of the e-PTFE membranes on both sides, even completely filling the pores. When the e-PTFE membrane roll cools, not only are the two e-PTFE membranes fixed together, but the heat-resistant material in the pores also provides excellent heat resistance for the e-PTFE membrane tube.

[0098] The heat-resistant material layer 4 includes at least one heat-resistant material with a hardness range of 20-40D. By selecting a heat-resistant material within this hardness range, the prepared e-PTFE membrane tube can possess reasonable support strength and elasticity.

[0099] The heat-resistant material is selected from at least one of Pebax (block polyether amide resin), TPU (thermoplastic polyurethane elastomer rubber), soft PVC (polyvinyl chloride) or silicone rubber.

[0100] The thickness of the heat-resistant material layer 4 ranges from 0.02 to 0.05 mm, which achieves the purpose of bonding the two adjacent e-PTFE membranes and providing heat resistance for the e-PTFE membrane tube, while avoiding the excessive time required for heating and melting of an excessively thick heat-resistant material layer 4, and the impact of an excessively thick heat-resistant material layer 4 on the supporting strength and elasticity of the prepared e-PTFE membrane tube.

[0101] The heating temperature range is 100-220℃. The holding temperature is the same as the heating temperature, and the holding time is 3-9 minutes. Since a heat-resistant material layer 4 is added in this embodiment, and the melting point of the heat-resistant material is lower than that of the adhesive, the required heating temperature is lower than that in Examples 5-8, and the required holding time is also reduced accordingly, thus further reducing production costs.

[0102] Example 10

[0103] Example 10 of this invention provides a method for preparing an e-PTFE membrane tube, comprising the following steps:

[0104] S1. Two layers of e-PTFE membranes with different fiber orientations are staggered by 90° according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0105] Optionally, see Figure 3 The fiber orientation of the first layer of e-PTFE membrane wound on the mold can be at 0° to the axis of the tooling mold (i.e., Figure 3If the first layer of e-PTFE membrane has a fiber orientation of 0° to the axis of the tooling mold, then the second layer of e-PTFE membrane has a fiber orientation of 90° to the axis of the tooling mold (i.e., ...). Figure 3 e-PTFE membrane with fiber orientation at 90° to the tooling mold axis 1);

[0106] S2. A heat-resistant material layer 4 is provided between two adjacent e-PTFE membranes with different fiber orientations, and the heat-resistant material layer 4 covers the outside of the first e-PTFE membrane.

[0107] The heat-resistant material layer 4 has a hardness of 20D.

[0108] The heat-resistant material is Pebax.

[0109] The thickness of the heat-resistant material layer 4 is 0.02 mm;

[0110] S3. Heat the e-PTFE membrane roll to 100°C and keep it at 100°C for 3 minutes. After cooling, the formed e-PTFE membrane roll is obtained.

[0111] S4. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0112] Example 11

[0113] Embodiment 11 of the present invention provides a method for preparing an e-PTFE membrane tube, comprising the following steps:

[0114] S1. Five layers of e-PTFE membrane with different fiber orientations are arranged with a 60° offset according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0115] S2. A heat-resistant material layer 4 is provided between two adjacent e-PTFE membranes with different fiber orientations, and the heat-resistant material layer 4 covers the outside of the first and third e-PTFE membranes.

[0116] The heat-resistant material layer 4 has a hardness of 30D.

[0117] The heat-resistant material is TPU;

[0118] The thickness of the heat-resistant material layer 4 is 0.035 mm;

[0119] S3. Heat the e-PTFE membrane roll to 160°C and keep it at 160°C for 6 minutes. After cooling, the formed e-PTFE membrane roll is obtained.

[0120] S4. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0121] Example 12

[0122] Embodiment 12 of the present invention provides a method for preparing an e-PTFE membrane tube, comprising the following steps:

[0123] S1. Eight layers of e-PTFE membrane with different fiber orientations are staggered by 45° according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding body.

[0124] S2. A heat-resistant material layer 4 is provided between each pair of adjacent e-PTFE membranes with different fiber orientations, and the heat-resistant material layer 4 covers the outside of the first 7 e-PTFE membranes.

[0125] The hardness range of the heat-resistant material layer 4 is 40D;

[0126] Among them, the heat-resistant material is selected from soft PVC and silicone rubber. The material of each heat-resistant material layer 4 is different. The first three layers are made of soft PVC, and the remaining layers are made of silicone rubber.

[0127] The thickness of the heat-resistant material layer 4 is 0.05 mm;

[0128] S3. Heat the e-PTFE membrane roll to 220°C and keep it at 220°C for 9 minutes. After cooling, the formed e-PTFE membrane roll is obtained.

[0129] S4. Remove the formed e-PTFE membrane roll from the tooling mold to obtain the e-PTFE membrane tube.

[0130] Example 13

[0131] Based on any one of Examples 1-12, Example 13 of the present invention provides a method for preparing an e-PTFE membrane tube, wherein the e-PTFE membrane is obtained by uniaxial stretching, the thickness of the e-PTFE membrane is 0.02 mm, and the node spacing of the e-PTFE membrane is 0.1 μm.

[0132] Example 14

[0133] Based on any one of Examples 1-12, Example 14 of the present invention provides a method for preparing an e-PTFE membrane tube, wherein the e-PTFE membrane is obtained by uniaxial stretching, the thickness of the e-PTFE membrane is 0.035 mm, and the node spacing of the e-PTFE membrane is 10 μm.

[0134] Example 15

[0135] Based on any one of Examples 1-12, Example 15 of the present invention provides a method for preparing an e-PTFE membrane tube, wherein the e-PTFE membrane is obtained by uniaxial stretching, the thickness of the e-PTFE membrane is 0.05 mm, and the node spacing of the e-PTFE membrane is 20 μm.

[0136] Example 16

[0137] To reduce the axial resistance of the e-PTFE membrane tube to the fluid passing through its inner cavity, preferably, the fiber orientation of the innermost e-PTFE membrane should be the same as the direction of the fluid. Therefore, based on any one of Examples 1-15, Example 16 of the present invention provides a method for preparing an e-PTFE membrane tube, wherein the fiber orientation of the first layer of e-PTFE membrane wound on the tooling mold is at 0° to the axis of the tooling mold.

[0138] Example 17

[0139] In the field of medical devices, e-PTFE membrane tubes are commonly used as artificial blood vessels for splicing with natural blood vessels. Since suturing is typically used when splicing with blood vessels, the end of the e-PTFE membrane tube that fits over the blood vessel needs to have a large diameter to facilitate insertion and suturing, and to prevent blood leakage after suturing.

[0140] Therefore, based on any one of Examples 1-16, Example 17 of the present invention provides a method for preparing an e-PTFE membrane tube, which uses a dumbbell-shaped tooling mold to prepare a dumbbell-shaped e-PTFE membrane tube with large diameters at both ends, making it easy to attach to blood vessels for suturing and preventing blood leakage after suturing.

[0141] The tooling includes a set of dumbbell-shaped bushings 5 ​​and dumbbell-shaped molds 6, with a fitting gap between the dumbbell-shaped bushings 5 ​​and the dumbbell-shaped molds 6. This fitting gap is used to accommodate multiple layers of e-PTFE membranes with different fiber orientations that are stacked and wound.

[0142] Furthermore, the dumbbell-shaped liner 5 includes a mandrel 51 and connecting end blocks 52 detachably connected to both ends of the mandrel 51; wherein, each connecting end block 52 is provided with a small side end and a large side end, the length of the small side end is less than the length of the large side end, the small side end is close to the mandrel 51, and the large side end is far away from the mandrel 51, thereby facilitating the removal of the formed e-PTFE membrane roll from the tooling mold.

[0143] It should be noted that when removing the formed e-PTFE membrane roll from the tooling mold, first remove the dumbbell-shaped mold 6 from the dumbbell-shaped liner 5, then remove the two connecting end blocks 52 from the mandrel 51, and then remove the mandrel 51 to obtain the dumbbell-shaped e-PTFE membrane tube.

[0144] Therefore, Embodiment 17 of the present invention can produce dumbbell-shaped e-PTFE membrane tubes, meeting the requirements for dumbbell-shaped e-PTFE membrane tubes.

[0145] Example 18

[0146] Example 18 of the present invention provides an e-PTFE membrane tube, which is made using the e-PTFE membrane tube preparation method of any one of Examples 1-17.

[0147] Furthermore, the diameters at both ends of the prepared e-PTFE membrane tube are larger than the diameter at the middle, and at least two layers of e-PTFE membrane with different fiber orientations are distributed radially. That is, the prepared e-PTFE membrane tube is dumbbell-shaped, which makes it easier to fit into blood vessels for suturing, thus meeting the requirements of dumbbell-shaped e-PTFE membrane tubes.

[0148] In summary, this invention prepares e-PTFE membrane tubes by staggering and stacking multiple layers of e-PTFE membranes with different limiting orientations. This results in e-PTFE membrane tubes with anisotropic high tensile strength and high suture tensile strength, meeting the performance requirements of e-PTFE membrane tubes. Furthermore, since uniaxially stretched finished e-PTFE membranes are used for stacking and winding, compared with e-PTFE membranes that are directly and simultaneously biaxially stretched, the production cost and manufacturing process difficulty are greatly reduced. At the same time, e-PTFE membrane tubes of different thicknesses can be prepared by stacking and winding multiple layers of e-PTFE membranes, adapting to the needs of e-PTFE membrane tubes of different thicknesses.

[0149] Furthermore, by adding adhesives or heat-resistant materials between the e-PTFE membranes, the membrane strength and heat resistance of the e-PTFE membrane tube can be improved, thus broadening the application range of e-PTFE membrane tubes in the medical field.

[0150] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that the steps in this invention are not limited in order. It should be pointed out that those skilled in the art can make several improvements and modifications without departing from the principle of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A method for preparing an e-PTFE membrane tube, characterized in that, Includes the following steps: At least two layers of e-PTFE membranes with different fiber orientations are staggered according to their respective fiber orientations and stacked and wound on a tooling mold to obtain an e-PTFE membrane winding. The e-PTFE membrane roll is heated and kept at a certain temperature, and then cooled to obtain the formed e-PTFE membrane roll. The formed e-PTFE membrane roll is removed from the tooling mold to obtain the e-PTFE membrane tube; The fiber orientation of the first layer of the e-PTFE membrane wound on the mold is at 0° to the axis of the tooling mold; The e-PTFE membrane tube has a larger diameter at both ends than at the middle, and has at least two layers of e-PTFE membrane with different fiber orientations distributed radially. The e-PTFE membrane is obtained by uniaxial stretching, the thickness of the e-PTFE membrane ranges from 0.02 to 0.05 mm, and the node spacing of the e-PTFE membrane ranges from 0.1 to 20 μm. By stacking and winding multiple layers of the e-PTFE membrane, e-PTFE membrane tubes of different thicknesses can be prepared. The tooling mold includes a set of dumbbell-shaped bushings and dumbbell-shaped molds, with a fitting gap between the dumbbell-shaped bushings and the dumbbell-shaped molds.

2. The method for preparing an e-PTFE membrane tube according to claim 1, characterized in that, The angle range of the misalignment of the two adjacent e-PTFE membranes with different fiber orientations is 45°-90°.

3. The method for preparing an e-PTFE membrane tube according to claim 2, characterized in that, The angle of the misalignment between two adjacent e-PTFE membranes with different fiber orientations is 90°.

4. The method for preparing an e-PTFE membrane tube according to claim 1, characterized in that, The number of layers in the e-PTFE membrane with different fiber orientations ranges from 2 to 8.

5. The method for preparing an e-PTFE membrane tube according to claim 1, characterized in that, The heating temperature range is 300-385℃.

6. The method for preparing an e-PTFE membrane tube according to claim 5, characterized in that, The temperature for heat preservation is the same as the temperature for heating, and the heat preservation time ranges from 5 to 20 minutes.

7. The method for preparing an e-PTFE membrane tube according to claim 1, characterized in that, It also includes the following steps: An adhesive layer is provided between two adjacent e-PTFE membranes with different fiber orientations.

8. The method for preparing an e-PTFE membrane tube according to claim 7, characterized in that, The adhesive layer includes at least one adhesive whose melting point is lower than that of the e-PTFE.

9. The method for preparing an e-PTFE membrane tube according to claim 8, characterized in that, The adhesive is selected from at least one of polytetrafluoroethylene, polyether-block polytetrafluoroethylene, or polypropylene.

10. The method for preparing an e-PTFE membrane tube according to claim 7, characterized in that, The thickness of the adhesive layer ranges from 0.02 to 0.05 mm.

11. The method for preparing an e-PTFE membrane tube according to claim 7, characterized in that, The adhesive layer covers the outside of the first layer of the e-PTFE membrane.

12. The method for preparing an e-PTFE membrane tube according to claim 7, characterized in that, The heating temperature range is 200-360℃.

13. The method for preparing an e-PTFE membrane tube according to claim 12, characterized in that, The temperature for heat preservation is the same as the temperature for heating, and the heat preservation time ranges from 4 to 15 minutes.

14. The method for preparing an e-PTFE membrane tube according to claim 1, characterized in that, It also includes the following steps: A heat-resistant material layer is provided between two adjacent e-PTFE membranes with different fiber orientations.

15. The method for preparing an e-PTFE membrane tube according to claim 14, characterized in that, The heat-resistant material layer includes at least one heat-resistant material, and the hardness of the heat-resistant material is in the range of 20-40D.

16. The method for preparing an e-PTFE membrane tube according to claim 15, characterized in that, The heat-resistant material is selected from at least one of Pebax, TPU, soft PVC or silicone rubber.

17. The method for preparing an e-PTFE membrane tube according to claim 14, characterized in that, The thickness of the heat-resistant material layer ranges from 0.02 to 0.05 mm.

18. The method for preparing an e-PTFE membrane tube according to claim 14, characterized in that, The heat-resistant material layer covers the outside of the first layer of the e-PTFE membrane.

19. The method for preparing an e-PTFE membrane tube according to claim 14, characterized in that, The heating temperature range is 100-220℃.

20. The method for preparing an e-PTFE membrane tube according to claim 19, wherein the heat preservation temperature is the same as the heating temperature, and the heat preservation time is 3-9 minutes.

21. The method for preparing an e-PTFE membrane tube according to claim 1, characterized in that, The dumbbell-shaped bushing includes a mandrel and connecting end blocks that are detachably connected to both ends of the mandrel; Each of the connecting end blocks is provided with a small side end and a large side end. The length of the small side end is less than the length of the large side end. The small side end is close to the mandrel, and the large side end is far away from the mandrel.

22. An e-PTFE membrane tube, characterized in that, It is manufactured using the preparation method of an e-PTFE membrane tube according to any one of claims 1-21.

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