PTFE (Polytetrafluoroethylene) etching pipe with bonding layer, multilayer composite pipe and preparation method of multilayer composite pipe

Abstract

The invention relates to the field of medical instruments, in particular to a PTFE etching pipe with a bonding layer, a multi-layer composite pipe and a preparation method of the multi-layer composite pipe. The PTFE etching pipe with the bonding layer sequentially comprises a PTFE base pipe, an etching layer and the bonding layer from inside to outside, the bonding layer is made of polyether block polyamide, polyamide, thermoplastic acrylic resin, silicone rubber or thermoplastic polyurethane elastomer, and the multi-layer composite pipe comprises the PTFE etching pipe with the bonding layer, a middle metal layer and an outer resin layer from inside to outside. Meanwhile, the invention further provides a preparation method of the PTFE etched pipe with the bonding layer and the multi-layer composite pipe, the bonding layer is additionally arranged to improve the bonding strength of the lining pipe and the outer sleeve and reduce the layering risk, compared with a contrast, the peeling strength is higher and larger than 3.4 kN / m, the composite pipe is not layered after aging for 79 days, the natural aging time is converted to be 3 years, and the composite pipe is not layered after aging for 3 years. The durability and the reliability of the catheter are improved, so that the manufacturing cost and the medical risk are reduced.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and particularly to a PTFE etched tube with an adhesive layer, a multi-layer composite tube and a preparation method thereof. Background Art

[0002] In the field of medical devices, especially in the manufacture of composite catheters, the adhesion strength between the inner liner and the outer jacket (also known as Jacket) is a key factor affecting product quality. In the existing technology, PTFE etched tubes are widely used due to their excellent chemical stability and biocompatibility. However, due to the low surface energy of the PTFE material, the adhesion force between it and the outer jacket is insufficient, which easily causes delamination, affecting the service life and safety of the catheter.

[0003] The structure of a typical interventional medical composite catheter usually consists of three layers. The inner layer is usually a PTFE etched tube (or liner); the middle layer is usually a metal wire structure layer, which can be in the form of a metal wire braid or a metal wire winding; the outer Jacket is usually a thermoplastic, and polyether block polyamide (PEBAX) is the most common. Through the thermal composite process (Reflow process), the outer resin on the Jacket can infiltrate, spread and finally achieve high-strength riveting on the surface of the etched tube with high activity in the viscous flow state, so that the composite tube has good integrity and does not delaminate.

[0004] In the existing technical solutions, in order to improve the adhesion between the PTFE etched tube and the catheter, the etching process is usually adjusted, such as adjusting the process parameters of the etching solution concentration, temperature, etching time, cleaning method after etching, etc., in order to obtain an etched tube with appropriate surface activity and roughness. Although the adhesion can be improved to a certain extent, there is still a risk of delamination.

[0005] For the Reflow process, the bonding force between the etched tube and the Jacket must be achieved through the outer resin that penetrates the metal layer. The amount of the outer resin that can reach the surface of the etched tube has a decisive impact on the bonding effect. However, adjusting the surface properties of the etched tube can only ensure that the outer resin reaching the surface of the etched tube is fully utilized, but cannot control the amount of the outer resin reaching the surface of the etched tube in the heated state. When the melting point of the outer resin is relatively high and the melt index is relatively low, making it difficult to flow during the Reflow process, even if the surface state of the etched tube is good, due to the lack of a sufficient amount of resin reaching the surface of the etched tube, it is still impossible to achieve sufficient wetting of the surface of the etched tube and form the aforementioned firm riveting structure. Moreover, for the etched tubes prepared by traditional processes, even at the beginning or for some time after the end of Reflow, although the bonding force between the layers of the composite tube is relatively high, its aging resistance is often poor. The reason is that although the riveting between the outer resin formed during Reflow and the etched tube has reached a certain level, since the amount of the outer resin penetrating the metal layer is limited, the number of riveting sites is still not enough and the degree of riveting is still not high. During long-term storage, this riveting layer will still fail, reducing the service life of the product. Summary of the Invention

[0006] Object of the Invention: The object of the present invention is to overcome the deficiencies of the above-mentioned existing technologies and provide a PTFE etched tube with an adhesive layer, a multi-layer composite tube and a preparation method thereof.

[0007] To achieve the above object, the technical solutions provided by the present invention are as follows:

[0008] In the first aspect of the present application, there is provided a PTFE etched tube with an adhesive layer, which sequentially includes a PTFE base tube, an etched layer, and an adhesive layer from the inside to the outside, wherein the material of the adhesive layer is polyether block polyamide, polyamide, thermoplastic acrylic resin, silicone rubber or thermoplastic polyurethane elastomer.

[0009] In some embodiments, the thickness of the adhesive layer is 0.0015 - 0.0076 mm.

[0010] In the second aspect of the present application, there is provided a multi-layer composite tube, including the PTFE etched tube with an adhesive layer described above.

[0011] In some embodiments, the multi-layer composite tube sequentially includes a PTFE etched tube with an adhesive layer, a middle metal layer, and an outer resin layer from the inside to the outside.

[0012] In some embodiments, the material of the outer resin layer of the multi-layer composite pipe is polyether block polyamide, polyamide or thermoplastic polyurethane elastomer, the thickness of the outer resin layer is 0.05 - 0.55 mm, and the thickness of the intermediate metal layer is 0.026 - 0.2 mm.

[0013] The third aspect of the present application provides a method for preparing the PTFE etched tube with an adhesive layer, comprising the following steps:

[0014] S1: Treat the PTFE base tube through a wet etching technique to form an etched layer on the surface, and obtain the PTFE etched tube;

[0015] S2: Heat the polymer raw material particles to 60 - 120 °C and dissolve them in an organic solvent under stirring. After complete dissolution, a solution is formed, and the solution is cooled to 25 - 50 °C;

[0016] S3: Seal both ends of the PTFE etched tube prepared in step S1, and immerse it in the solution described in S2 to form an adhesive layer, and the soaking time is 10 s - 10 min;

[0017] S4: Take out the tube soaked in S3 and dry it to obtain the PTFE etched tube with an adhesive layer.

[0018] In some embodiments, in step S2 of the method for preparing the PTFE etched tube with an adhesive layer, the material of the polymer raw material particles includes polyether block polyamide, polyamide, thermoplastic acrylic resin, silicone rubber or thermoplastic polyurethane elastomer, the mass percentage of the polymer raw material particles in the solution is 2 - 40%, and the organic solvent is one or more of alcohol solvents, ketone solvents, and ester solvents. In some embodiments, the organic solvent is one or more of ethanol, n-butanol, n-propanol, isopropanol, glycerol, acetone, methyl ketone, cyclohexanone, ethyl acetate, and butyl butyrate.

[0019] The fourth aspect of the present application provides a method for preparing the multi-layer composite pipe, comprising the following steps:

[0020] S1: Put the PTFE etched tube with an adhesive layer on the stainless steel inner liner mandrel;

[0021] S2: Weave metal wires or wind a spring on its surface to form an intermediate metal layer;

[0022] S3: Sheath a resin outer tube on the intermediate metal layer to form an outer resin layer;

[0023] S4: Sheath an FEP heat shrinkable tube on the outer tube and perform thermal lamination;

[0024] S5: After the thermal lamination is completed, peel off the FEP heat shrinkable tube and extract the stainless steel inner liner mandrel to form the multi-layer composite pipe.

[0025] In some embodiments, the method for preparing the multi-layer composite tube is characterized in that in step S4, the heat shrinkage ratio of the FEP heat shrinkable tube is 1.3 - 2.0, and the conditions for the thermal composite are: the temperature is 200 - 300 °C and the speed is 0.9 - 3 mm / s.

[0026] Beneficial effects: The present invention relates to the field of medical devices, and specifically relates to a PTFE etched tube with an adhesive layer, a multi-layer composite tube and a preparation method thereof. The PTFE etched tube with an adhesive layer sequentially includes a PTFE base tube, an etched layer, and an adhesive layer from the inside to the outside, wherein the material of the adhesive layer is polyether block polyamide, polyamide, thermoplastic acrylic resin, silicone rubber or thermoplastic polyurethane elastomer. The multi-layer composite tube sequentially includes a PTFE etched tube with an adhesive layer, an intermediate metal layer, and an outer resin layer from the inside to the outside. At the same time, the present application also provides a preparation method for the PTFE etched tube with an adhesive layer and the multi-layer composite tube. The schematic diagram compared with Comparative Example 1 is as Figure 6 shown. For the multi-layer tube of the inner layer PTFE etched tube + intermediate layer metal layer + outer layer resin layer, during reflow, the outer layer resin cannot completely fill the micro-grooves on the surface of the etched tube, leaving voids and prone to delamination. For the multi-layer tube of the inner layer PTFE etched tube with an adhesive layer + intermediate metal layer + outer layer resin layer, during reflow, the adhesive layer is pre-filled into the micro-grooves of the etched tube sufficiently. During thermal composite, the outer layer resin is more likely to combine with the adhesive layer, making the multi-layer tube less prone to delamination. Adding an adhesive layer can improve the adhesion strength between the inner liner and the outer sleeve, reduce the delamination risk, and the peeling strength of this solution is stronger, with a force greater than 3.4 kN / m. After aging test for 79 days, the composite tube does not delaminate, and the equivalent natural aging time is 3 years without delamination, improving the durability and reliability of the catheter, thereby reducing the manufacturing cost and medical risk. Description of the Drawings

[0027] Figure 1 is a scanning electron micrograph of the surface of the PTFE base tube;

[0028] Figure 2 is a scanning electron micrograph of the surface of the PTFE etched tube;

[0029] Figure 3 is a scanning electron micrograph of the outer surface of the PTFE etched tube with an adhesive layer;

[0030] Figure 4 is a schematic structural diagram of the PTFE etched tube with an adhesive layer;

[0031] Figure 5 is a schematic structural diagram of the multi-layer composite tube;

[0032] Figure 6 is a schematic diagram of the principle comparison of this solution with the comparative example;

[0033] Among them, the corresponding reference numerals in the figure are as follows:

[0034] 1 - PTFE etched tube with an adhesive layer; 1-1 - PTFE base tube; 1-2 - etched layer; 1-3 - adhesive layer; 4 - intermediate metal layer; 5 - outer resin layer. Specific embodiments

[0035] The following further clarifies the present invention in conjunction with specific embodiments. These embodiments are implemented on the premise of the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0036] Embodiment 1

[0037] Prepare a PTFE etched tube with an adhesive layer:

[0038] S1: Treat the PTFE base tube 1-1 through a wet etching technique to form an etched layer 1-2 on the surface, and obtain a PTFE etched tube;

[0039] S2: Take 10 g of PEBAX5533 (polyether block polyamide 5533) particles and 190 g of n-butanol, add them to a beaker respectively, and heat and stir in an oil bath at 100 °C. After 2 hours, it is completely dissolved, and the solution is cooled to 40 °C;

[0040] S3: Seal the two ends of the PTFE etched tube prepared in step S1, and immerse it in the solution described in S2 to form an adhesive layer 1-3, and the soaking time is 10 min;

[0041] S4: Take out the tube soaked in S3, hang it naturally to dry, and obtain a PTFE etched tube 1 with an adhesive layer, and the thickness of the adhesive layer is 0.003 mm.

[0042] Preparation steps for a multi-layer composite tube of a PTFE etched tube with an adhesive layer:

[0043] S1: Put the PTFE etched tube 1 with an adhesive layer on a stainless steel inner liner mandrel;

[0044] S2: Weave it on its surface with stainless steel metal flat wires in a 1-over-2 weaving pattern to form an intermediate metal layer 4;

[0045] S3: Sheath an outer tube made of PEBAX5533 (polyether block polyamide 5533) with a thickness of 0.15 mm on the intermediate metal layer 4 to form an outer resin layer 5;

[0046] S4: Sheath an FEP heat shrinkable tube on the outer tube, with a heat shrinkage ratio of 1.6, and perform heat lamination at a temperature of 230 °C and a speed of 2 mm / s;

[0047] S5: After the thermal lamination is completed, remove the FEP heat-shrinkable tube and pull out the stainless steel inner core shaft to form a multi-layer composite tube.

[0048] Example 2

[0049] Prepare a PTFE etched tube with an adhesive layer:

[0050] S1: Treat the PTFE base tube 1-1 through a wet etching technique to form an etched layer 1-2 on the surface and obtain a PTFE etched tube;

[0051] S2: Take 20 g of PA12 (polyamide 12) particles and 313 g of n-butanol, add them to a beaker respectively, heat and stir in an oil bath at 80 °C. After 2 hours, it is completely dissolved, and the solution is cooled to 50 °C;

[0052] S3: Seal the two ends of the PTFE etched tube prepared in step S1, immerse it in the solution described in S2 to form an adhesive layer 1-3, and the soaking time is 10 min;

[0053] S4: Take out the tube soaked in S3, hang it naturally to dry, and obtain a PTFE etched tube 1 with an adhesive layer, and the thickness of the adhesive layer is 0.0025 mm.

[0054] Preparation steps for the multi-layer composite tube of the PTFE etched tube with an adhesive layer:

[0055] S1: Put the PTFE etched tube 1 with an adhesive layer on the stainless steel inner core shaft;

[0056] S2: Wind a stainless steel spring around its surface to form an intermediate metal layer 4;

[0057] S3: Sheath an outer tube with a thickness of 0.3 mm of PA12 (polyamide 12) on the intermediate metal layer 4 to form an outer resin layer 5;

[0058] S4: Sheath an FEP heat-shrinkable tube on the outer tube, with a heat shrinkage ratio of 1.8, and perform thermal lamination at a temperature of 230 °C and a speed of 1.5 mm / s;

[0059] S5: After the thermal lamination is completed, remove the FEP heat-shrinkable tube and pull out the stainless steel inner core shaft to form a multi-layer composite tube.

[0060] Example 3

[0061] Prepare a PTFE etched tube with an adhesive layer:

[0062] S1: Treat the PTFE base tube 1-1 through a wet etching technique to form an etched layer 1-2 on the surface and obtain a PTFE etched tube;

[0063] S2: Take 20 g of PMMA (polymethyl methacrylate) particles and 180 g of cyclohexanone, add them to a beaker respectively, and heat and stir in an oil bath at 100 °C. After 2 hours, it is completely dissolved, and the solution is cooled to 40 °C;

[0064] S3: Seal both ends of the PTFE etching tube prepared in step S1, immerse it in the solution described in S2 to form an adhesive layer 1-3, and the soaking time is 5 min;

[0065] S4: Take out the tube soaked in S3, hang it naturally to dry, and obtain a PTFE etching tube 1 with an adhesive layer, and the thickness of the adhesive layer is 0.005 mm.

[0066] Preparation steps of a multi-layer composite tube of a PTFE etching tube with an adhesive layer:

[0067] S1: Put the PTFE etching tube 1 with an adhesive layer on a stainless steel inner liner mandrel;

[0068] S2: Weave it on its surface with stainless steel flat wires in a 1-over-2 weaving pattern to form an intermediate metal layer 4;

[0069] S3: Sheath an outer tube with a thickness of 0.35 mm of PEBAX6333 (polyether block polyamide 6333) on the metal layer to form an outer resin layer 5;

[0070] S4: Sheath an FEP heat shrinkable tube on the outer tube, with a heat shrinkage ratio of 1.8, and perform heat lamination at a temperature of 230 °C and a speed of 1 mm / s;

[0071] S5: After the heat lamination is completed, peel off the FEP heat shrinkable tube and pull out the stainless steel inner liner mandrel to form a multi-layer composite tube.

[0072] Example 4

[0073] Preparation of a PTFE etching tube with an adhesive layer:

[0074] S1: Treat the PTFE base tube 1-1 through a wet etching technique to form an etching layer 1-2 on the surface, and obtain a PTFE etching tube;

[0075] S2: Take TM Liveo TM 10 g of QP1-40 (silicone rubber QP1-40) particles and 490 g of ethyl acetate, add them to a beaker respectively, and heat and stir in an oil bath at 70 °C. After 3 hours, it is completely dissolved, and the solution is cooled to 30 °C;

[0076] S3: Seal both ends of the PTFE etching tube prepared in step S1, immerse it in the solution described in S2 to form an adhesive layer 1-3, and the soaking time is 15 min;

[0077] S4: Take out the tube after being soaked in S3, hang it naturally to dry, and obtain the PTFE etched tube 1 with an adhesive layer, and the thickness of the adhesive layer is 0.003 mm.

[0078] Preparation steps of the multi-layer composite tube of the PTFE etched tube with an adhesive layer:

[0079] S1: Put the PTFE etched tube 1 with an adhesive layer on the stainless steel inner liner mandrel;

[0080] S2: Wind a nickel-titanium spring around its surface to form the intermediate metal layer 4;

[0081] S3: Sheath an outer tube of PEBAX7233 (polyether block polyamide 7233) with a thickness of 0.5 mm on the metal layer to form the outer resin layer 5;

[0082] S4: Sheath an FEP heat-shrinkable tube on the outer tube with a heat shrinkage ratio of 1.8, and perform heat lamination at a temperature of 240 °C and a speed of 1 mm / s;

[0083] S5: After the heat lamination is completed, peel off the FEP heat-shrinkable tube and draw out the stainless steel inner liner mandrel to form a multi-layer composite tube.

[0084] Example 5

[0085] Preparation of the PTFE etched tube with an adhesive layer:

[0086] S1: Treat the PTFE base tube 1-1 through a wet etching technique to form an etched layer 1-2 on the surface, and obtain the PTFE etched tube;

[0087] S2: Take 10 g of TPU1185A (thermoplastic polyurethane elastomer 1185A) particles and 156 g of acetone, add them to a beaker respectively, heat and stir in an oil bath at 60 °C. After 2 hours, it is completely dissolved, and the solution is cooled to 30 °C;

[0088] S3: Seal the two ends of the PTFE etched tube prepared in step S1, and immerse it in the solution described in S2 to form an adhesive layer 1-3, and the soaking time is 5 min;

[0089] S4: Take out the tube after being soaked in S3, hang it naturally to dry, and obtain the PTFE etched tube 1 with an adhesive layer, and the thickness of the adhesive layer is 0.006 mm.

[0090] Preparation steps of the multi-layer composite tube of the PTFE etched tube with an adhesive layer:

[0091] S1: Put the PTFE etched tube 1 with an adhesive layer on the stainless steel inner liner mandrel;

[0092] S2: Weave it on its surface with nickel-titanium metal flat wires in a 2-over-2 weaving pattern to form an intermediate metal layer 4;

[0093] S3: Sheath a layer of TPU1185A (thermoplastic polyurethane elastomer 1185A) with a thickness of 0.4 mm on the metal layer to form an outer resin layer 5;

[0094] S4: Sheath a layer of FEP heat-shrinkable tube on the outer tube with a heat shrinkage ratio of 1.8, and perform heat lamination at a temperature of 220 °C and a speed of 2 mm / s;

[0095] S5: After the heat lamination is completed, peel off the FEP heat-shrinkable tube and draw out the stainless steel inner core shaft to form a multi-layer composite tube, and its structure is as Figure 5 shown. The scanning electron microscope image of the surface of the PTFE base tube 1-1 is as Figure 1 shown, the scanning electron microscope image of the surface of the PTFE etched tube is as Figure 2 shown, the scanning electron microscope image of the outer surface of the PTFE etched tube 1 with an adhesive layer is as Figure 3 shown, and the structural schematic diagram of the PTFE etched tube 1 with an adhesive layer is Figure 4 shown. It can be seen from Figure 1 , 2 and 3 that there are no microscopic grooves on the outer surface of the PTFE base tube 1-1, there are microscopic grooves on the outer surface of the PTFE etched tube, and there are no microscopic grooves and it is flat on the outer surface of the PTFE etched tube 1 with an adhesive layer. The fact that there are no microscopic grooves and it is flat on the outer surface of the PTFE etched tube 1 with an adhesive layer indicates that the adhesive layer fully infiltrates into the microscopic grooves on the surface of the etched tube and forms a riveting structure.

[0096] Comparative Example 1

[0097] Preparation steps of the multi-layer composite tube of the PTFE etched tube:

[0098] 1. Put the PTFE etched tube on the stainless steel core shaft;

[0099] 2. Weave it on its surface with stainless steel metal flat wires in a 1-over-2 weaving pattern to form a metal layer;

[0100] 3. Sheath a layer of PEBAX5533 (polyether block polyamide 5533) with a thickness of 0.15 mm outside the metal layer;

[0101] 4. Sheath a layer of FEP heat-shrinkable tube on the outer tube with a heat shrinkage ratio of 1.6, and perform heat lamination at a temperature of 230 °C and a speed of 2 mm / s;

[0102] 5. After the heat lamination is completed, peel off the outermost FEP heat-shrinkable tube and draw out the stainless steel core shaft to obtain a multi-layer composite tube.

[0103] Comparative Example 2

[0104] Preparation steps of the multi-layer composite pipe of the PTFE-based pipe:

[0105] 1. Put the PTFE-based pipe on the stainless steel mandrel;

[0106] 2. Weave the stainless steel flat wire on its surface in a 1-over-2 weaving pattern to form a metal layer;

[0107] 3. Put an outer pipe of PEBAX5533 (polyether block polyamide 5533) with a thickness of 0.15 mm outside the metal layer;

[0108] 4. Put an FEP heat shrinkable tube outside the outer pipe with a heat shrinkage ratio of 1.6, and perform heat lamination at a temperature of 230 °C and a speed of 2 mm / s;

[0109] 5. After the heat lamination is completed, peel off the outermost FEP heat shrinkable tube and draw out the stainless steel mandrel to obtain the multi-layer composite pipe.

[0110] Test example

[0111] Peel test of the composite pipe

[0112] Test method: In accordance with GB / T 2790-1995 "Test Method for 180° Peel Strength of Adhesives - Flexible Materials to Rigid Materials", the test equipment is an electronic universal testing machine, the test rate is 100 mm / min, test the peel strength of the PTFE etched tube with an adhesive layer and the outer tube after lamination, and evaluate the change of its surface adhesion.

[0113] Calculate the peel strength according to formula (1):

[0114]

[0115] In the formula:

[0116] σ 180。 ---180° peel strength, kN / m;

[0117] F---Peeling force, N;

[0118] B---Specimen width, mm.

[0119] Select the multi-layer composite pipes of Examples 1-5 and Comparative Examples 1-2, test their peel strengths, and make a comparative analysis as shown in Table 1 below.

[0120] Table 1 Peel test results of the composite pipe

[0121]

[0122]

[0123] Aging test

[0124] Test method: In accordance with YY / T 0681.1-2018 "Test Methods for Packaging of Sterile Medical Devices - Part 1: Guidelines for Accelerated Aging Test", Examples 1-5 and Comparative Example 1 were selected. The temperature of the aging test was 60 °C and the humidity was 22%. The delamination of the corresponding multi-layer composite pipes at different aging times was analyzed and compared, as shown in Table 2 below.

[0125] Using the Arrhenius formula, taking Q 10 equal to 2 is a common and conservative method for calculating the aging factor.

[0126] Calculate the estimated value of the accelerated aging factor according to formula (2):

[0127] AAF = Q 10 [(TAA-TRT) / 10] .........(2)

[0128] In the formula:

[0129] AAF ---- Accelerated aging factor;

[0130] T AA ---- Accelerated aging temperature, in degrees Celsius (°C);

[0131] T RT ---- Ambient temperature, in degrees Celsius (°C).

[0132] Determine the accelerated aging time using formula (3):

[0133] AAT = RT / AAF.............(3)

[0134] In the formula:

[0135] AAT ---- Accelerated aging time;

[0136] RT ---- Desired or required actual time;

[0137] AAF ---- Accelerated aging factor

[0138] Table 2 Results of the aging test

[0139]

[0140]

[0141] As shown in Table 1 and Table 2, in Examples 1-5, the multi-layer composite pipe was subjected to a peel test, and its peel strength was greater than 3.4 kN / m. After aging for 79 days, the composite pipe did not delaminate. The equivalent natural aging time was 3 years without delamination, and its peel strength was greater than 2.5 kN / m. In Comparative Example 1, the multi-layer composite pipe was subjected to a peel test, and its peel strength was 2.6 kN / m. After aging for 53 days, the composite pipe did not delaminate. The equivalent natural aging time was 2 years without delamination, and its peel strength was 1.2 kN / m. After aging for 79 days, the composite pipe delaminated.

[0142] Compared with Comparative Example 1, in Examples 1-5, there is an adhesive layer on the PTFE etched pipe, and the composite pipe has a stronger peel strength and a longer aging time, that is, a longer effective storage time.

[0143] Compared with Comparative Example 2, in Examples 1-5, there is an etched pipe layer and an adhesive layer on the PTFE. The composite pipe has a stronger peel strength. When there is no etched layer on the PTFE, its composite ability is poor and it is extremely easy to delaminate.

[0144] The above specific embodiments further elaborate on the purpose, technical solutions, and beneficial effects of the present application. It should be understood that the above are only specific embodiments of the present application and are not used to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solutions of the present application shall be included in the protection scope of the present application.

Claims

1. A PTFE etching tube (1) with an adhesive layer, characterized in that: From the inside to the outside, it comprises a PTFE base tube (1-1), an etching layer (1-2), and a bonding layer (1-3), wherein the material of the bonding layer (1-3) is polyether block polyamide, polyamide, thermoplastic acrylic resin, silicone rubber or thermoplastic polyurethane elastomer.

2. The method for preparing the PTFE etching tube (1) with an adhesive layer according to claim 1, characterized in that: The thickness of the bonding layer (1-3) is 0.0015-0.0076 mm.

3. A multi-layer composite pipe, characterized in that: The invention comprises a PTFE etching tube with an adhesive layer as described in any one of claims 1 to 2.

4. A multi-layer composite pipe according to claim 3, characterized in that: From the inside to the outside, it comprises a PTFE etching tube (1) with an adhesive layer, a middle metal layer (4), and an outer resin layer (5).

5. A multi-layer composite pipe according to claim 4, characterized in that: The material of the outer resin layer (5) is polyether block polyamide, polyamide or thermoplastic polyurethane elastomer, the thickness of the outer resin layer (5) is 0.05-0.55 mm, and the thickness of the intermediate metal layer (4) is 0.026-0.2 mm.

6. A method for preparing the PTFE etching tube (1) with an adhesive layer as claimed in any one of claims 1 to 2, characterized in that: The following steps are involved: S1: treating a PTFE base tube (1-1) by wet etching technology to form an etching layer (1-2) on the surface, thereby preparing a PTFE etching tube; S2: heating the polymer raw material particles to 60-120°C under stirring and dissolving them in an organic solvent to form a solution after they are completely dissolved, and cooling the solution to 25°C-50°C; S3: Seal both ends of the PTFE etching tube prepared in step S1, and immerse it in the solution described in step S2 to form a bonding layer (1-3), and the immersion time is 10s-30min; S4: Drying to obtain a PTFE etched tube (1) with an adhesive layer.

7. The method for preparing the PTFE etching tube (1) with an adhesive layer according to claim 6, characterized in that: In step S2, the material of the polymer raw material particles includes polyether block polyamide, polyamide, thermoplastic acrylic resin, silicone rubber or thermoplastic polyurethane elastomer, the mass percentage of the polymer raw material particles in the solution is 2-40%, and the organic solvent is one or more of alcohol, ketone or ester solvents.

8. The method for preparing the PTFE etching tube (1) with an adhesive layer according to claim 7, characterized in that: The organic solvent is one or more of ethanol, n-butanol, n-propanol, isopropanol, glycerol, acetone, ketone, cyclohexanone, ethyl acetate or butyl butyrate.

9. A method for preparing the multilayer composite pipe according to any one of claims 3 to 5, characterized in that: The following steps are involved: S1: inserting the PTFE etched tube (1) with an adhesive layer onto the stainless steel lined mandrel; S2: a metal wire is woven or spring is wound on its surface to form an intermediate metal layer (4); S3: Covering the middle metal layer (4) with a resin outer tube to form an outer resin layer (5); S4: Put a layer of FEP heat shrink tube on the outer tube for thermal bonding; S5: After the thermal compounding is completed, the FEP heat shrink tube is peeled off and the stainless steel lined mandrel is pulled out to form a multi-layer composite tube.

10. The method for preparing a multi-layer composite pipe according to claim 9, characterized in that: In step S4, the heat shrinkage ratio of the FEP heat shrinkable tube is 1.3-2.0, and the conditions of the heat compounding are: temperature of 200-300° C. and speed of 0.9-3 mm / s.

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