A medical catheter surface super-lubricating coating and a method for preparing the same

Abstract

The application discloses a kind of medical catheter surface superlubricity coating and preparation method thereof, belong to medical instrument field, coating solution is coated on the medical catheter surface after nitrogen plasma treatment, further ultraviolet light curing and heat curing obtain the medical catheter surface superlubricity coating of described;The coating solution includes polyurethane acrylate, acrylic acid, ultraviolet light initiator, thermal crosslinking agent, functional polymer and solvent, wherein, the mass ratio of polyurethane acrylate, acrylic acid and functional polymer is 3-8:1:1-3, the mass fraction of acrylic acid is 1.6-2.4wt%, and functional polymer is at least one of polyvinylpyrrolidone, polyethylene glycol, hydroxypropyl methyl cellulose, hyaluronic acid, chitosan.The superlubricity coating and the binding force of medical catheter are good, stability and friction performance are excellent, and its single-layer structure is simple, curing time is short, and market application prospect is widely.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of medical devices, in particular to a medical catheter surface super-lubricating coating and a preparation method thereof. BACKGROUND

[0002] Interventional medical catheters are widely used in clinical practice, including urinary catheters, nasal catheters, gastric tubes, anal tubes, tracheal tubes, etc. Interventional medical catheters are used to diagnose and treat diseases locally by passing through the body cavity. However, these medical devices often contain a large amount of hydrophobic polymers, such as silicone rubber, polyurethane, polyethylene, polypropylene, latex, polyether block polyamide, etc. They have a large friction with human tissues, causing pain in patients, and even leading to trauma and infection at the use site, seriously affecting the treatment effect and harming the health of patients. Hydrophilic lubricating coating is one of the key technologies to solve this problem, which can improve the low wettability of the surface of medical devices while not damaging their mechanical properties.

[0003] The hydrophilic coating on the surface of medical devices can form a hydration layer when wet, greatly reducing the friction coefficient of the device surface. In addition, the hydration layer can reduce protein adsorption, reduce the incidence of infection and thrombosis, and to a large extent meet the needs of short-term use in the body. However, most coatings have poor compatibility with the substrate, and are often accompanied by the risk of particle leakage and even coating shedding during use, leading to serious consequences such as aseptic inflammation, vascular embolism, and tissue necrosis. Therefore, the stability of the hydrophilic coating is crucial.

[0004] Currently, a widely used hydrophilic lubricating coating technology is based on a solidification scheme of high molecular weight hydrophilic polymers. This type of coating is usually composed of a primer and a topcoat. First, a resin such as polyurethane or acrylate is used as the main component on the surface of the substrate to form a primer layer through polymerization, which strongly bonds with the substrate to form a primer layer, thereby bonding the substrate with the hydrophilic functional layer. Then, a hydrophilic lubricating topcoat is further constructed on the primer, which mainly uses a reactive polymer backbone and hydrophilic polymers such as polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), or polysaccharides as the main components, which are firmly combined with the primer (or form an interpenetrating network) through solidification, to achieve good hydrophilic lubricating effect.

[0005] A Chinese patent document with publication number CN114163912A discloses an interventional catheter surface coating, which includes a base coating and a top coating. The base coating includes a water-based polyurethane emulsion, polyvinyl alcohol, deionized water, a wetting agent, and a silane coupling agent. The top coating includes an acrylamide-modified vinylpyrrolidone polymer, a water-based polyurethane, trehalose, an isooctanol polyoxyethylene ether, a surfactant, a citrate plasticizer, an organic solvent, and deionized water. The base coating and the top coating in the coating are covalently bonded and cross-linked to form an interpenetrating network structure, enhancing the tight connection between the coatings.

[0006] The hydrophilic lubricating coating obtained by the above two-step dip coating and curing has advantages of high efficiency and cleanliness. The curing methods include ultraviolet light curing and thermal curing. The ultraviolet light curing coating has a gradient in the depth direction due to the radiation intensity attenuation and other factors, which leads to the decrease of the swelling performance and hydration ability of the coating. Furthermore, the conventional ultraviolet light curing polyurethane acrylate has only two cross-linkable double bonds at the end groups, so that the cross-linking density is limited, and the firmness of the formed coating needs to be further improved. The thermal curing can uniformly transfer heat to all positions of the coating, reduce the gradient of the coating in the depth direction, and process irregular surfaces. However, the thermal curing usually has a long curing time, generally needs to be heated at 80 DEG C or higher for 15-30 min, is easy to damage the substrate, and is not conducive to efficient production, which to some extent limits the popularization of the method. SUMMARY

[0007] The application provides a medical catheter surface super-lubricating coating, which has good adhesion to the medical catheter, excellent stability and friction performance, and does not significantly increase the friction coefficient after 30 reciprocating friction cycles. The single-layer structure of the coating is simple, the curing time is short, and the market application prospect is wide.

[0008] The specific technical solutions are as follows:

[0009] A medical catheter surface super-lubricating coating is obtained by coating a coating solution on the surface of a medical catheter treated by nitrogen plasma, and then performing ultraviolet light curing and thermal curing.

[0010] The coating solution comprises polyurethane acrylate, acrylic acid, ultraviolet light initiator, thermal cross-linking agent, functional polymer and solvent. The mass ratio of the polyurethane acrylate, the acrylic acid and the functional polymer is 3-8:1:1-3, the mass fraction of the acrylic acid is 1.6-2.4 wt%, the mass ratio of the ultraviolet light initiator to the polyurethane acrylate and the acrylic acid is 2-5:100, and the mass ratio of the thermal cross-linking agent to the acrylic acid is 3-6:100.

[0011] The ultraviolet light curing time is 2-5 min, and the thermal curing time is 5-10 min.

[0012] The functional polymer is at least one of polyvinylpyrrolidone, polyethylene glycol, hydroxypropyl methyl cellulose, hyaluronic acid and chitosan.

[0013] The application performs plasma treatment on the surface of a medical catheter to clean and activate the surface (endow the surface with free radicals), and then coats a coating solution of specific components, in which the unsaturated bond between the polyurethane acrylate and the acrylic acid is crosslinked by end-to-end under the action of ultraviolet light, and the carboxyl group of the acrylic acid is polycondensed under the action of heat with a thermal crosslinking agent. The application stabilizes the polymer skeleton through a short-time treatment mode of dual crosslinking of light / thermal crosslinking, forms a firm interpenetrating network structure of the polymer skeleton and the functional lubricating polymer, firmly fixes the functional lubricating polymer in the coating, and makes the polymer skeleton and the surface of the medical catheter after plasma treatment have high adhesion, so that the prepared coating has excellent lubricating performance and stability, and can greatly reduce the time required for the curing process.

[0014] The medical catheter includes but is not limited to a TPU nasogastric feeding tube, a TPU balloon catheter, a silicone urinary catheter, a latex urinary catheter, a PVC nasogastric feeding tube, a medical PEBAX catheter, etc.

[0015] The coating method includes but is not limited to a spraying method, a dipping method, etc.

[0016] Preferably, the polyurethane acrylate is difunctional polyurethane acrylate, which contains two active groups that can participate in the photocuring reaction in the molecule of the bifunctional polyurethane acrylate, and has a fast photocuring rate.

[0017] Preferably, the ultraviolet light initiator is benzophenone (BP) or 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (I2959).

[0018] Preferably, the thermal crosslinking agent is polyaziridine and / or carbodiimide.

[0019] Specifically, the solvent is at least one of ethanol, dichloromethane, isopropyl alcohol and water.

[0020] Preferably, the functional polymer is polyvinylpyrrolidone, and the weight average molecular weight of the polyvinylpyrrolidone is 360,000-1,300,000. The wrapped polyvinylpyrrolidone has strong water absorption in a liquid environment, thereby showing high lubricity.

[0021] Further preferably, the mass ratio of the polyurethane acrylate, the acrylic acid and the functional polymer is 4-6:1:1.5-3, the mass fraction of the acrylic acid is 1.8-2.2 wt%, the mass ratio of the ultraviolet light initiator to the polyurethane acrylate and the acrylic acid is 3-4:100, and the mass ratio of the thermal crosslinking agent to the acrylic acid is 3-4:100. The product prepared under the above parameters has more stable coating performance.

[0022] Preferably, the UV curing parameters are 320-400 nm, 2-5 min; the heat curing parameters are 50-80℃, 5-10 min. Based on the acrylate and heat curing agent in the formula in the present application, the curing time is too long, which may cause the crosslinking degree of the polymer to be too high, thereby reducing the friction coefficient of the coating.

[0023] The present application also provides a preparation method of the medical catheter surface super-lubricating coating, comprising the following steps:

[0024] (1) placing the medical catheter in a plasma device for N2 plasma treatment, and the treatment conditions are as follows: N2 flow rate 50-200 mL / min, bombardment power 100-300 W, and bombardment time 60-300 s;

[0025] (2) coating the coating solution on the surface of the medical catheter obtained in step (1), and then sequentially performing UV curing and heat curing, and then cleaning, drying, and obtaining the medical catheter surface super-lubricating coating.

[0026] Preferably, in step (2), the coating method is dip coating, and the specific operation steps are as follows: the coating solution is loaded into a dip coater, the medical catheter is dipped into the coating solution at a speed of 0.4-1.0 cm / s, and then lifted up at a speed of 1-3 cm / s, and then exposed to UV light at 320-400 nm for 2-5 min, and the rotating speed of the clamp is 5-15 r / min during the exposure, and then the medical catheter is transferred to 50-80℃ for heat curing for 5-10 min.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] (1) The medical catheter surface super-lubricating coating prepared by the method of the present application has good integrity, the polymer skeleton is stabilized by the light / heat crosslinking double crosslinking method, and the functional polymer is fixed in the coating due to the interpenetrating network structure formed by the polymer skeleton (polyurethane acrylate) and the functional polymer, so that the coating has good lubricating performance and a low average friction coefficient.

[0029] (2) The medical catheter surface super-lubricating coating provided by the present application has good stability, and the friction coefficient does not increase significantly after 30 reciprocating friction cycles.

[0030] (3) The method of the present application has simple preparation process, easy-to-obtain raw materials, simple single-layer coating structure, short curing time, easy operation, low production cost, and wide market application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a schematic view of the medical catheter surface super-lubricating coating.

[0032] Figure 2 Optical photograph of the medical catheter surface super-lubricant coating after Congo red staining. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0034] In the examples and comparative examples, the difunctional polyurethane acrylate used is purchased from Guangzhou Lihou Trade Co., Ltd.

[0035] Examples 1-7

[0036] (1) The medical catheter (TPU nasogastric tube) was placed in a plasma device for N2 plasma treatment, and the treatment conditions were as follows: N2 flow rate 100 mL / min, bombardment power 100 W, and bombardment time 120 s;

[0037] (2) The coating solution was loaded into a dip coater, and the coating solution was coated on the surface of the medical catheter obtained in step (1) by dip coating, the medical catheter was controlled to be immersed in the coating solution at a speed of 1.0 cm / s, and was pulled up at a speed of 1 cm / s, then was exposed to ultraviolet light at 365 nm for 5 min, the rotation speed of the clamp was 10 r / min during exposure, after ultraviolet curing, the medical catheter was transferred to 60°C for thermal curing for 5 min, then was placed in water for cleaning, and after drying, the medical catheter surface super-lubricant coating was obtained.

[0038] Specifically, in Examples 1-7, the formula of the coating solution is shown in Table 1:

[0039] Table 1 Formula of the coating solution in Examples 1-7

[0040]

[0041] The above coating solution is prepared on demand, and the storage period is 48 h.

[0042] Example 8

[0043] The difference between this example and Example 1 is that the N2 plasma treatment conditions are as follows: N2 flow rate 200 mL / min, bombardment power 300 W, and bombardment time 200 s.

[0044] Example 9

[0045] The difference between this example and Example 1 is that the medical catheter is selected as PEBAX catheter (block polyether amide resin), and the N2 plasma treatment conditions are as follows: N2 flow rate is 300 mL / min, bombardment power is 150 W, and bombardment time is 100 s.

[0046] Example 10

[0047] The difference between this example and Example 1 is that, in the process of preparing the coating by dip-coating method, the medical catheter is immersed into the coating solution at a speed of 0.8 cm / s, pulled up at a speed of 2.0 cm / s, then exposed to the ultraviolet light at 365 nm for 4 min, the rotating speed of the clamp is 5 r / min during the exposure, and after the ultraviolet curing, the medical catheter is transferred to 70°C for thermal curing for 9 min.

[0048] Example 11

[0049] The difference between this example and Example 1 is that, in the process of preparing the coating by dip-coating method, the medical catheter is immersed into the coating solution at a speed of 0.6 cm / s, pulled up at a speed of 3.0 cm / s, then exposed to the ultraviolet light at 365 nm for 3 min, the rotating speed of the clamp is 8 r / min during the exposure, and after the ultraviolet curing, the medical catheter is transferred to 60°C for thermal curing for 8 min.

[0050] Comparative Example 1

[0051] The difference between this example and Example 1 is that, only the ultraviolet curing is performed by exposing to the ultraviolet light at 365 nm for 5 min, and no thermal curing is performed.

[0052] Comparative Example 2

[0053] The difference between this example and Example 1 is that, only the thermal curing is performed at 60°C for 5 min, and no ultraviolet curing is performed.

[0054] Comparative Example 3

[0055] The difference between this example and Example 1 is that, the thermal curing parameters are 80°C and 30 min.

[0056] Sample Analysis

[0057] The schematic diagram of the super-lubricating coating on the surface of the medical catheter is shown in Figure 1 .

[0058] (1) The integrity of the super-lubricating coating on the surface of the medical catheter

[0059] The medical catheter surface super-lubricating coating prepared in Example 1, 8, 9, 10 and Comparative Example 1, 2 was immersed in 1% (w / v) aqueous solution of Congo red for 30 seconds, then the excess dye solution on the surface was washed off under running water, and the coating was naturally air-dried and photographed for the staining condition, and the results are shown in Fig. 1. Figure 2 The coating prepared in Example 1, 8, 9, 10 was dyed by Congo red, and the staining was uniform without uncolored part, and the coating had good integrity. However, the coating prepared in Comparative Example 1, 2 was dyed by Congo red, and the staining was not uniform with uncolored part, and the coating had poor integrity.

[0060] (2) Measurement of the friction coefficient and firmness of the medical catheter surface super-lubricating coating

[0061] The friction test of the medical catheter surface super-lubricating coating was carried out in a 37℃ constant temperature water bath. The sample was immersed in the 37℃ water bath for 1 minute, and then two pieces of silicone rubber with Shore hardness of 55A in the friction tester were used to apply a constant clamping force of 300g to the coating area of the catheter, the position of the two pieces of silicone rubber was adjusted to clamp the sample, and the sample was pulled up at a speed of 5mm / s, the test distance was 50mm, then the clamp was opened, the sample was moved down to the starting height of the first test, then the clamp was tightened again, and the average force value was the friction force, and the friction coefficient was calculated; the cycle was repeated for 30 times, and the average friction force F1 of the first 5 cycles and the average friction force F2 of the last 5 cycles were taken respectively, and the percentage value (F2 / F1) of F2 and F1 was calculated, which should be not more than 130%, i.e. good firmness.

[0062] The results of the friction performance test of the coatings of Example 1-11 and Comparative Example 1-3 are shown in Table 2, and the results of the firmness test are shown in Table 3. It can be seen that the friction coefficient of the medical catheter surface super-lubricating coating prepared by the present application Example 1-11 is less than 0.05, which has super-lubricity. The friction coefficients of the 1st, 10th and 30th cycles were calculated from the measured friction data, and Table 3 shows that the friction coefficient of the coating changes little after 30 times of friction, and is less than 0.05, and F2 / F1 is not more than 130%, which indicates that the coating has small abrasion and good firmness. The friction coefficient of the coating of Comparative Example 1-2 is much greater than 0.05, and F2 / F1 is much greater than 130%, which indicates that the coating has poor lubricity and firmness. In Comparative Example 3, the heat curing time was prolonged to 30 minutes, and the firmness of the coating was improved (F2 / F1 is much less than 130%), but the lubricity of the coating was decreased (the friction coefficient is greater than 0.05), which may be due to the fact that the high molecular lubricant is densely embedded in the coating due to the high crosslinking degree of the polymer, and it is difficult to be wetted by water to play its lubricating role. In addition, similar experimental results show that the coating obtained by the method of the present application on various medical catheters has super-lubricity and good firmness, which indicates that the super-lubricating coating has universality for different medical catheters, and has broad market.

[0063] Table 2 Results of the friction force performance test of the coatings of Examples 1-11 and Comparative Examples 1-3

[0064] Item 1st friction coefficient 10th friction coefficient 30th friction coefficient Example 1 0.032 0.034 0.037 Example 2 0.022 0.025 0.026 Example 3 0.026 0.028 0.031 Example 4 0.036 0.039 0.043 Example 5 0.028 0.030 0.032 Example 6 0.039 0.040 0.045 Example 7 0.029 0.029 0.035 Example 8 0.031 0.034 0.036 Example 9 0.029 0.031 0.033 Example 10 0.034 0.035 0.040 Example 11 0.036 0.040 0.041 Comparative Example 1 0.24 0.37 0.45 Comparative Example 2 0.26 0.34 0.42 Comparative Example 3 0.079 0.082 0.083

[0065] Table 3 Results of the firmness test of the coatings of Examples 1-11 and Comparative Examples 1-3

[0066] Item F1 F2 F2 / F1 (%) Example 1 9.5 11.2 118 Example 2 6.3 8.0 127 Example 3 7.6 9.5 125 Example 4 10.7 12.2 114 Example 5 8.2 9.9 121 Example 6 11.5 13.8 120 Example 7 8.5 10.7 126 Example 8 9.1 11 121 Example 9 8.2 9.9 121 Example 10 10 12.2 122 Example 11 10.5 12.5 119 Comparative Example 1 72 135 188 Comparative Example 2 79 128 162 Comparative Example 3 23.6 24.9 106

[0067] The above described examples have been described in detail for the technical solutions of the present application, it should be understood that the above described is only a specific embodiment of the present application, and is not used to limit the present application, any modification, supplement or similar way of substitution made within the principle range of the present application should be included in the protection scope of the present application.

Claims

1. A medical catheter surface coating, characterized in that, The coating solution is coated on the surface of the medical catheter treated by N2 plasma, and the medical catheter surface coating is obtained by ultraviolet curing and heat curing. The ultraviolet curing time is 2-5 min; the heat curing temperature is 50-80℃; and the heat curing time is 5-10 min. The coating solution comprises polyurethane acrylate, acrylic acid, ultraviolet light initiator, heat crosslinking agent, functional polymer and solvent, wherein the mass ratio of polyurethane acrylate, acrylic acid and functional polymer is 3-8:1:1-3, the mass fraction of acrylic acid is 1.6-2.4wt%, the mass ratio of ultraviolet light initiator to polyurethane acrylate and acrylic acid is 2-5:100, and the mass ratio of heat crosslinking agent to acrylic acid is 3-6:

100. The functional polymer is at least one of polyvinylpyrrolidone, polyethylene glycol, hydroxypropyl methyl cellulose, hyaluronic acid and chitosan.

2. The medical catheter surface coating of claim 1, wherein, The coating method comprises spraying or dipping.

3. The medical catheter surface coating of claim 1, wherein, The polyurethane acrylate is difunctional polyurethane acrylate.

4. The medical catheter surface coating of claim 1, wherein, The ultraviolet light initiator is benzophenone or 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone; the heat crosslinking agent is polyaziridine and / or carbodiimide; and the solvent is at least one of ethanol, dichloromethane, isopropanol and water.

5. The medical catheter surface coating of claim 1, wherein, The mass ratio of polyurethane acrylate, acrylic acid and functional polymer is 4-6:1:1.5-3, the mass fraction of acrylic acid is 1.8-2.2wt%, the mass ratio of ultraviolet light initiator to polyurethane acrylate and acrylic acid is 3-4:100, and the mass ratio of heat crosslinking agent to acrylic acid is 3-4:

100.

6. The medical catheter surface coating of claim 1, wherein, The wavelength parameter of ultraviolet curing is 320-400 nm.

7. The method of claim 1-6, wherein the medical catheter surface coating is prepared by, The method comprises the following steps: (1) placing the medical catheter in a plasma device for N2 plasma treatment, wherein the treatment conditions are as follows: N2 flow rate 50-200 mL / min, bombardment power 100-300 W, and bombardment time 60-300 s; (2) coating the coating solution on the surface of the medical catheter obtained in step (1), and then sequentially performing ultraviolet curing and heat curing, cleaning, and air drying to obtain the medical catheter surface coating.

8. The method of claim 7, wherein the medical catheter surface coating is prepared by, In step (2), the coating method is dipping, and the specific operation steps are as follows: the coating solution is loaded into a dipping instrument, the medical catheter is dipped into the coating solution at a speed of 0.4-1.0 cm / s, and then lifted up at a speed of 1-3 cm / s, followed by exposure to ultraviolet light at 320-400 nm for 2-5 min, and the rotation speed of the clamp is 5-15 r / min during exposure, and then the medical catheter is transferred to 50-80℃ for heat curing for 5-10 min.

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