A mandrel coating method and its use

Abstract

The application relates to the technical field of para-aramid material, in particular to a mandrel coating method and application thereof. The coating method comprises the following steps: S1, sand blasting: using sand blasting materials to perform sand blasting treatment on the mandrel; S2, cleaning: first performing surface cleaning by using diluted acid liquid, and then performing rinsing by using deionized water; S3, pretreatment: soaking by using a silane coupling agent; and S4, coating: depositing poly-p-xylylene on the surface of the mandrel, and the mandrel coating method can simultaneously realize lubricating performance of the mandrel and meet the biological compatibility performance; the lubricating friction coefficient is less than 0.25; when the mandrel is used as a mold, the film layer does not fall off and the film does not break after the sleeve is repeatedly taken off for 20-70 times after heat shrinkage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of parylene material, and more particularly to a mandrel coating method and application thereof. BACKGROUND

[0002] The vascular stent is a kind of tubular stent made of metal material or high polymer material, which is placed into the stenosis and occlusion segment of the blood vessel on the basis of balloon dilatation to support the stenosis and occlusion segment of the blood vessel, reduce the elastic recoil and reshaping of the blood vessel, and thus keep the blood flow unobstructed. It belongs to a kind of vascular interventional instrument. At present, the vascular stent has been widely used in the treatment of coronary artery, intracranial artery, carotid artery, renal artery and femoral artery diseases, and has achieved remarkable curative effect. Parylene is a kind of completely linear and highly crystalline polymeric material, which is a new type of conformal coating material developed and applied by Union Carbide Co. in the mid-1960s. It is chemically inert, insoluble in acid, alkali and organic solvent, and can resist hydrolysis and corrosion. The thin film coating formed by this technology can cover the edges and gaps of the silk fabric, and the surface is hydrophobic, with poor permeability to water vapor and corrosive gas, good thermal stability, and good isolation and protection function in harsh environments such as acid mist, mold, humidity and corrosion.

[0003] The preparation method of the vascular coating stent provided by CN103705324B comprises: passing a mandrel coaxially through the cavity of the vascular stent body, the Shore hardness D of the surface layer or the whole of the mandrel is less than 60 or greater than 86; changing the gap between the outer surface of the mandrel and the inner wall of the vascular stent until they are seamlessly contacted or partially contacted; spraying coating liquid on the vascular stent body; and removing the mandrel. This method can prepare a coating stent with coating on the outer wall and the side wall, and no coating or discontinuous coating on the inner wall, which effectively controls the amount of coating on the inner wall of the vascular coating stent.

[0004] At present, the mandrel of the vascular stent has poor biocompatibility in use, and the lubricating effect and wear resistance of the mandrel are poor, so the mandrel is easily worn during work, thereby shortening the service life of the mandrel. Therefore, a mandrel lubricating coating is proposed to increase the lubricating property and biocompatibility of the mandrel surface, reduce the frictional resistance, and thus prolong the service life of the vascular stent. SUMMARY

[0005] The first aspect of the present application provides a mandrel coating method, comprising the following steps:

[0006] S1, sand blasting: using sand blasting material to perform sand blasting treatment on the mandrel;

[0007] S2, cleaning: first using dilute acid solution for surface cleaning, then using deionized water for rinsing;

[0008] S3, pre-treatment: using silane coupling agent for soaking;

[0009] S4, coating: depositing parylene on the surface of the mandrel, and obtaining the same.

[0010] The grit blasting material has a mesh size of 40-200 mesh, the grit blasting pressure is 0.8-5 Pa, and the grit blasting direction includes one of straight blasting and oblique blasting.

[0011] The coating of parylene on the substrate is that active small molecules grow into a completely conformal polymer film coating on the surface of the substrate. The coating is applied to various shaped surfaces, including sharp edges, cracks and inner surfaces, but there are problems of poor adhesion of the coating to the substrate and easy peeling. The applicant has found that the grit blasting material has a mesh size of 40-200 mesh, the grit blasting pressure is 0.8-5 Pa, which can improve the lubricity of the coating to the substrate and the adhesion between the coating and the substrate, effectively solve the problem of coating peeling, and possibly improve the microtopography of the contact surface by grit blasting with a specific mesh size, form a specific microporous structure between the substrate and the coating, match a specific deposition process, and produce adhesion by Van der Waals force between molecules to achieve pore covering while maintaining high smoothness.

[0012] Preferably, the grit blasting material has a mesh size of 50-200 mesh, the grit blasting pressure is 0.8-4 Pa, and the grit blasting direction includes one of straight blasting and oblique blasting.

[0013] The dilution ratio of the acid solution is 1-10 wt%.

[0014] The applicant has found that first using dilute acid solution for surface cleaning, then using deionized water for rinsing, and the dilution ratio of the acid solution being 1-10 wt%, not only can remove the residues left on the substrate surface by grit blasting, but also can form a microporous etching effect on the substrate surface, which is beneficial to the surface treatment of the substrate by the silane coupling agent. It is speculated that the grit blasting forms a micro-nano concave structure, and the specific acid solution performs surface cleaning, expands the concave structure to a certain extent, and smooths the edges of the concave structure, which is consistent with the morphology of the parylene particles deposited in the subsequent step.

[0015] Preferably, the dilution ratio of the acid solution is 1-8 wt%.

[0016] The acid solution includes one of phosphoric acid, hydrochloric acid and nitric acid.

[0017] The conductivity of the deionized water is <20 s / cm.

[0018] The conductivity of the deionized water is < 20 s / cm. The deionized water is cleaner and has no residue. If the conductivity is not within the range, there will be more impurities, and residues on the surface will affect the bonding force.

[0019] Preferably, the conductivity of the deionized water is < 10 s / cm.

[0020] The silane coupling agent comprises the following functional groups: acryloyloxy, allyl, vinyl, and alkoxy silane.

[0021] The general structure of the silane coupling agent includes [R n SiO (4-n) / 2 ] m , wherein n is 1-3, and m is 1-3.

[0022] The Si / O atomic ratio of the silane coupling agent is 0.5-2.

[0023] The silane coupling agent comprises Q-type structure (Si / O = 0.5) and T-type structure (Si / O = 2), and the mass ratio of the Q-type structure to the T-type structure is (0-2):(1-3).

[0024] The applicant has found that the silane coupling agent comprises Q-type structure (Si / O = 0.5) and T-type structure (Si / O = 2), and the mass ratio of the Q-type structure to the T-type structure is (0-2):(1-3), so that the mandrel is used as a mold, and the membrane layer does not fall off or break after the sleeve is repeatedly removed 20-70 times or more after heat shrinkage. The surface of the substrate after sandblasting surface treatment has a microporous surface, and forms a mechanical locking physical effect with the coating. Under the action of shear force for a long time, interlayer slip occurs, leading to damage to the membrane layer. After sandblasting treatment, a more firm chemical bonding force is formed between the substrate and the coating through the treatment of a specific silane coupling agent, which is also more conducive to the deposition of poly-p-xylylene on the mandrel.

[0025] Preferably, the mass ratio of the Q-type structure to the T-type structure is 0:1.

[0026] Further preferably, the silane coupling agent comprises at least one of A174 (γ-methacryloyloxypropyltrimethoxysilane) and A151 (vinyltriethoxysilane).

[0027] The pressure of the deposition is 30-70 mTorr, and the speed of the deposition is 1-2 um / hour, which can improve the toughness of the coating, and the lubricating friction coefficient is less than 0.25, further improving the number of repeated use after the shrinkage of the sleeve. When the pressure increases, the surface free energy increases due to the relatively large number of polar components on the surface, and the contact angle gradually decreases. The contact angle prepared at a certain pressure is low, the surface has a relatively high surface tension and hydrophilicity, and the wettability is better. However, if the deposition rate is too high, the reaction time of the double radical end polymerization will be shortened, resulting in a low average molecular weight of the film and a low smoothness of the film surface.

[0028] The Parylene includes at least one of unsubstituted dimeric parylene (N type), dichloro-substituted dimeric parylene (C type), 4,7,12,15-tetrachloro-substituted dimeric parylene (D type), 3,4,11,12-tetrachloro-substituted dimeric parylene, 4,5,12,13-tetrachloro-substituted dimeric parylene, 4,5,12,13-tetrabromo-substituted dimeric parylene, 1,1,2,2,9,9,10,10-octafluoro[2.2]dimeric parylene (AF type), and 4,5,7,8,12,13,15,16-octafluoro-substituted dimeric parylene.

[0029] Preferably, the Parylene includes at least one of unsubstituted dimeric parylene (N type) and dichloro-substituted dimeric parylene (C type).

[0030] Further preferably, the Parylene includes unsubstituted dimeric parylene (N type).

[0031] The pressure of the deposition is 30-70 mTorr.

[0032] Preferably, the pressure of the deposition is 40-50 mTorr.

[0033] The thickness of the deposition is 1-10 um.

[0034] Preferably, the thickness of the deposition is 2-5 um.

[0035] The speed of the deposition is 0.5-2 um / hour.

[0036] Preferably, the speed of the deposition is 1-2 um / hour.

[0037] Further preferably, the speed of the deposition is 1 um / hour.

[0038] The second aspect of the application provides an application of a mandrel coating method, which is applied to the auxiliary preparation of balloon catheters and balloon welding.

[0039] Advantages:

[0040] 1. The mandrel coating method of the present application can simultaneously achieve the lubrication performance of the mandrel and meet the biocompatibility performance.

[0041] 2. The grit blasting material has a mesh size of 40-200 mesh and a blasting pressure of 0.8-5 Pa, which can improve the lubrication performance of the coating on the substrate and the adhesion performance between the coating and the substrate, and effectively solve the problem of coating peeling.

[0042] 3. The surface is first cleaned with diluted acid solution and then rinsed with deionized water, and the dilution ratio of the acid solution is 1-10 wt%, which not only removes the residues left on the surface of the substrate after grit blasting treatment, but also forms a microporous etching effect on the surface of the substrate, which is beneficial to the surface treatment and deposition effect of the silane coupling agent on the substrate.

[0043] 4. The silane coupling agent includes Q-type structure (Si / O=0.5) and T-type structure (Si / O=2), and the mass ratio of the Q-type structure to the T-type structure is (0-2):(1-3), so that the mandrel is used as a mold, and the film layer does not peel off or break after the sleeve is repeatedly shrunk 20-70 times.

[0044] 5. The deposition pressure is 30-70 mTorr, and the deposition speed is 1-2 um / hour, which can improve the toughness of the coating, and at the same time, the lubrication friction coefficient is less than 0.25, further improving the number of repeated uses after the sleeve is shrunk. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 Biocompatibility-sensitization test results after mandrel coating of Example 1

[0046] Figure 2 Biocompatibility-acute systemic toxicity test results after mandrel coating of Example 1

[0047] Figure 3 Biocompatibility-intradermal reaction test results after mandrel coating of Example 1

[0048] Figure 4 Biocompatibility-in vitro cytotoxicity test results after mandrel coating of Example 1

[0049] Figure 5 Mandrel surface after 30 times of sleeve shrinkage for Example 1

[0050] Figure 6 Mandrel surface before sleeve shrinkage for Example 2, and mandrel surface after 60 times of sleeve shrinkage DETAILED DESCRIPTION

[0051] Example 1, a mandrel coating method, is the following steps:

[0052] S1, sand blasting: sand blasting material (brown corundum) 50 mesh, pressure 0.8 pa, straight blasting, time 5 minutes, on the mandrel (stainless steel material);

[0053] S2, cleaning: use 1wt% nitric acid diluent to clean 1 time for 3 minutes, rinse with deionized water (grade: AR, resistivity MΩ.cm. (25°C) ≥0.5, greater than 1 μm particle number ≤500; greater than 0.5 μm particle number ≤2000) 3 times, 3 minutes each time;

[0054] S3, pre-treatment process: 0.5wt% A174 (isopropyl alcohol as solvent) (γ-methacryloxypropyl trimethoxysilane) soaking for 30 minutes;

[0055] S4, coating: add Parylene N type 30g, add coupling agent (A174) 5ml, set the deposition gas pressure 30mTorr, the average deposition rate 1um / hour, when the deposition thickness reaches 1um, turn off the equipment.

[0056] Example 2, a mandrel coating method, is the following steps:

[0057] S1, sand blasting: sand blasting material 140 mesh (brown corundum), pressure 2 pa, time 5 minutes;

[0058] S2, cleaning: use 3wt% nitric acid diluent to clean 1 time for 3 minutes, rinse with deionized water (grade: AR, resistivity MΩ.cm. (25°C) ≥0.5, greater than 1 μm particle number ≤500; greater than 0.5 μm particle number ≤2000) 3 times, 3 minutes each time;

[0059] S3, pre-treatment: 0.5wt% A174 soaking for 30 minutes;

[0060] S4, coating: add Parylene N type 90g, add coupling agent 5ml, set the deposition gas pressure 30mTorr, the average deposition rate 1um / hour, when the deposition thickness reaches 3um, turn off the equipment.

[0061] Example 3, a mandrel coating method, is the following steps:

[0062] S1, sand blasting: sand blasting material 200 mesh (brown corundum), pressure 4 pa, time 5 minutes;

[0063] ​S2, cleaning: clean with 8wt% nitric acid dilution for 3 minutes once, rinse with deionized water (grade: AR, resistivity MΩ.cm. (25°C) > 0.5, number of particles > 1 μm ≤ 500; number of particles > 0.5 μm ≤ 2000) for 3 times, 3 minutes each time;

[0064] S3, pre-treatment process: soak with 0.5wt% A174 for 30 minutes;

[0065] S4, coating: add Parylene N type 200g, add coupling agent 5ml, set deposition pressure 65mTorr, average deposition speed 1um / hour, when the deposition thickness reaches 7um, turn off the equipment.

[0066] Example 4, a mandrel coating method, the following steps:

[0067] S1, sand blasting: sand blasting material 100 mesh (brown corundum), pressure 3pa, time 5 minutes;

[0068] S2, cleaning: clean with 6wt% nitric acid dilution for 3 minutes once, rinse with deionized water (grade: AR, resistivity MΩ.cm. (25°C) > 0.5, number of particles > 1 μm ≤ 500; number of particles > 0.5 μm ≤ 2000) for 3 times, 3 minutes each time;

[0069] S3, pre-treatment process: soak with 0.5wt% A174 for 30 minutes;

[0070] S4, coating: add Parylene N type 120g, add coupling agent 5ml, set deposition pressure 50mTorr, average deposition speed 1um / hour, when the deposition thickness reaches 4um, turn off the equipment.

[0071] Comparative Example 1, a mandrel coating method, the following steps:

[0072] S1, cleaning: soak with 75wt% IPA (isopropyl alcohol) aqueous solution for 30 minutes, clean for 5 minutes;

[0073] S2, coating: add Parylene N type 60g, add coupling agent 5ml, set deposition pressure 30mTorr, average deposition speed 1um / hour, when the deposition thickness reaches 2um, turn off the equipment.

[0074] Comparative Example 2, a mandrel coating method, the following steps:

[0075] S1, cleaning: clean with 3wt% nitric acid dilution for 3 minutes, rinse with deionized water (grade: AR, resistivity MΩ.cm. (25°C) > 0.5, number of particles > 1 μm ≤ 500; number of particles > 0.5 μm ≤ 2000) for 3 times, 3 minutes each time;

[0076] S2, pre-treatment process: soak in 0.8wt% A174 for 30 minutes;

[0077] S3, coating: add Parylene C type 40g, add coupling agent 5ml, set deposition pressure 15 mTorr, average deposition speed 1 um / hour, when the deposition thickness reaches 2 um, turn off the equipment.

[0078] Comparative Example 3, a mandrel coating method, is the following steps:

[0079] S1, sand blasting: sand blasting material 500 mesh (brown corundum), pressure 3 pa, time 5 minutes;

[0080] S2, cleaning: soak in 75wt% IPA (isopropyl alcohol) solution for 30 minutes, clean for 5 minutes;

[0081] S3, pre-treatment process: soak in 0.5wt% A174 for 30 minutes;

[0082] S4, coating: add Parylene N type 15g, add coupling agent 5ml, set deposition pressure 30 mTorr, average deposition speed 1 um / hour, when the deposition thickness reaches 0.5 um, turn off the equipment.

[0083] Comparative Example 4, a mandrel coating method, is the following steps:

[0084] S1, sand blasting: sand blasting material 300 mesh (brown corundum), pressure 3 pa, time 5 minutes;

[0085] S2, cleaning: clean with 3wt% nitric acid dilution for 3 minutes, rinse with deionized water for 3 times, 3 minutes each time;

[0086] S3, pre-treatment process: soak in 0.5wt% A174 for 30 minutes;

[0087] S4, coating: add Parylene N type 30g, add coupling agent 5ml, set deposition pressure 30 mTorr, average deposition speed 1 um / hour, when the deposition thickness reaches 1 um, turn off the equipment.

[0088] Comparative Example 5, a mandrel coating method, is the following steps:

[0089] S1, sand blasting: sand blasting (brown corundum) 50 mesh on mandrel (stainless steel material), pressure 0.8 pa, straight blasting, time 5 minutes;

[0090] S2, cleaning: using 1wt% nitric acid diluent to clean 3 minutes 1 time, deionized water (grade: AR, resistivity MΩ.cm. (25℃) ≥0.5, greater than 1 μm particle number ≤500; greater than 0.5 μm particle number ≤2000) rinsing 3 times, 3 minutes each time;

[0091] S3, pre-treatment process: 0.5wt% KH550 soaking 30 minutes;

[0092] S4, coating: adding Parylene N type 30g, adding coupling agent (KH550) 5ml, setting deposition gas pressure 30mTorr, average deposition speed 1um / hour, when the deposition thickness reaches 1um, turning off the equipment.

[0093] Comparative Example 6, a mandrel coating method, the following steps:

[0094] S1, sand blasting: sand blasting (brown corundum) 50 mesh on mandrel (stainless steel material), pressure 0.8 pa, straight blasting, time 5 minutes;

[0095] S2, cleaning: using 1wt% nitric acid diluent to clean 3 minutes 1 time, deionized water (grade: AR, resistivity MΩ.cm. (25℃) ≥0.5, greater than 1 μm particle number ≤500; greater than 0.5 μm particle number ≤2000) rinsing 3 times, 3 minutes each time;

[0096] S3, 0.5wt% KH560 soaking 30 minutes;

[0097] S4, coating: adding Parylene N type 30g, adding coupling agent (KH560) 5ml, setting deposition gas pressure 30mTorr, average deposition speed 1um / hour, when the deposition thickness reaches 1um, turning off the equipment.

[0098] Performance test method

[0099] The mandrels in the examples and comparative examples were subjected to the following performance tests:

[0100] 1, the mandrel was used as a mold, after the sleeve was heat-shrunk, it was repeatedly used, the film layer was peeled off, the film was broken, the experiment was stopped, the number of repeated use was recorded, and the test data were listed in Table 1.

[0101] 2, biocompatibility test, as shown in Figures 1-4 .

[0102] Performance test data

[0103] Table 1

[0104] Number of uses Example 1 30 Example 2 60 Example 3 45 Example 4 60 Comparative Example 1 1 Comparative Example 2 1 Comparative Example 3 10 Comparative Example 4 16 Comparative Example 5 8 Comparative Example 6 15

Claims

1. A mandrel coating method characterized by, The method comprises the following steps: S1, sand blasting: using sand blasting material to perform sand blasting treatment on the mandrel; S2, cleaning: first using diluted acid liquid to perform surface cleaning, and then using deionized water to perform rinsing; S3, pre-treatment: using silane coupling agent to perform soaking; S4, coating: depositing poly-p-xylene on the surface of the mandrel, and obtaining the same; The sand blasting material has a mesh number of 40-200 meshes, the sand blasting pressure is 0.8-5 Pa, and the sand blasting direction includes one of straight blasting and oblique blasting; The acid liquid has a dilution ratio of 1-10 wt%, the acid liquid includes one of phosphoric acid, hydrochloric acid and nitric acid, and the conductivity of the deionized water is less than 20 s / cm; The silane coupling agent is γ-methacryloxypropyl trimethoxysilane; The deposition pressure is 30-70 mTorr, the deposition thickness is 1-10 μm, and the deposition speed is 0.5-2 μm / hour.

2. A mandrel coating method according to claim 1, wherein The poly-p-xylene includes at least one of unsubstituted dimeric p-xylene, dichloro-substituted dimeric p-xylene, 4,7,12,15-tetrachloro-substituted dimeric p-xylene, 3,4,11,12-tetrachloro-substituted dimeric p-xylene, 4,5,12,13-tetrachloro-substituted dimeric p-xylene, 4,5,12,13-tetrabromo-substituted dimeric p-xylene, 1,1,2,2,9,9,10,10-octafluoro[2.2]dimeric p-xylene and 4,5,7,8,12,13,15,16-octafluoro-substituted dimeric p-xylene.

3. Use of the mandrel coating method according to claim 1, characterized in that The method is applied to the auxiliary preparation of balloon catheters and balloon welding.

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