High-molecular hydrophobic coating based on EVOH hydrogen-resistant coating surface and preparation method of high-molecular hydrophobic coating
By preparing an adhesion layer, a hydrogen-retardant layer and a hydrophobic layer on the surface of the EVOH hydrogen-retardant coating, the aqueous polyurethane and modified silica modified by silane coupling agent were solved, and the problem of high H2 transmittance caused by the hydrophilicity of the EVOH coating was achieved, and an efficient H2 barrier effect was achieved.
Patent Information
- Application Number
- CN202510406888.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-02
- Publication Date
- 2025-07-04
AI Technical Summary
The existing EVOH hydrogen-resisting coatings have a deterioration in the material properties after water molecules absorption due to hydrophilicity, which affects the H2 barrier effect.
Three layers of coatings were prepared on the surface of the EVOH hydrogen-retardant coating, including an adhesion layer, a hydrogen-retardant layer and a hydrophobic layer. The surface hydrophobicity was improved by using silane coupling agent-modified aqueous polyurethane and modified silica, and the KH-PU/FS-SiO2 coating was prepared by physical mixing method.
It improves the hydrophobicity of the coating, reduces the contact between water molecules and the hydrogen-resisting layer, enhances the H2 barrier performance, and makes the coating preparation method simple and does not require high-temperature drying.
Smart Images
Figure FT_1
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of inner surface treatment of hydrogen transmission pipelines and type IV hydrogen storage cylinders, and particularly relates to a polymer hydrophobic coating based on an EVOH hydrogen barrier coating surface and a preparation method thereof. Background Art
[0002] The development of renewable energy and non-polluting energy is an important proposition in the energy field at the present stage. Hydrogen energy is an ideal medium for the large-scale development of renewable energy, and renewable energy can be converted into hydrogen energy for storage. For the large-scale application of hydrogen energy, "hydrogen transmission" is a crucial link. Non-metallic plastic pipelines and polymer-lined hydrogen storage tanks have the advantages of light weight and corrosion resistance, and are expected to become the main equipment for future H2 storage and transportation. However, for the problem of high H2 permeability commonly existing in polymer materials, it is urgent to develop new coating materials with high H2 barrier performance. EVOH has high H2 barrier properties. The reason why it can effectively block H2 is that the EVOH structure contains polar groups such as -OH, which means that the coating has hydrophilicity. When the coating comes into contact with water, the water is gradually absorbed, the material will be plasticized, and the bonds between and within molecules will be weakened, resulting in a decrease in the barrier performance. To solve this problem, the present invention prepares a hydrophobic coating on the basis of an EVOH hydrogen barrier coating, aiming to improve the surface hydrophobicity of the coating and prevent the influence of water contact with the coating on the hydrogen barrier effect. Summary of the Invention
[0003] The purpose of the present invention is to provide a polymer hydrophobic coating based on an EVOH hydrogen barrier coating surface applicable to the inside of hydrogen transmission pipelines and type IV hydrogen storage cylinders and a preparation method thereof, which uses surface treatment technology to reduce the H2 permeability of materials while improving surface hydrophobicity.
[0004] A polymer hydrophobic coating based on an EVOH hydrogen barrier coating surface is formed on a nylon 6 substrate and consists of three layers of coatings. The first layer, the adhesion layer, is a nylon treatment agent to improve the adhesion between the barrier layer and the substrate; the second layer is the hydrogen barrier layer, which is composed of a composite of ethylene-vinyl alcohol copolymer (EVOH) and polyethyleneimine (PEI) modified graphene oxide (GO); the third layer, the hydrophobic layer, uses waterborne polyurethane (WPU) modified with silane coupling agent (KH550) as the main raw material, and adds silica (SiO2) modified with trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane (FS1710) as a filler, and prepares the KH-PU / FS-SiO2 coating by physical mixing.
[0005] Furthermore, the preparation method of the trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane modified silica (FS-SiO2) is as follows:
[0006] Step G1: Ultrasonically disperse nano-SiO₂ in absolute ethanol at a concentration of 1 mg / mL and ultrasonicate for 1.5 h at room temperature to achieve full dispersion;
[0007] Step G2: Use a pipette to measure an appropriate amount of FS1710 and then slowly drop it into the continuously stirred nano-SiO₂ dispersion, and stir at room temperature for 24 h;
[0008] Step G3: Filter and wash the product of Step G2 three times with absolute ethanol, and then vacuum dry the product at 60 °C for 6 h;
[0009] Step G4: Grind the product of G3 and sieve it through a 200-mesh sieve to obtain the final product FS-SiO₂ powder.
[0010] Furthermore, for the silane coupling agent-modified waterborne polyurethane (KH-PU), its preparation method is as follows:
[0011] Step S1: Take an appropriate amount of WPU and dilute it with the same mass of deionized water. Place the solution on a magnetic stirrer and stir at room temperature for 20 min;
[0012] Step S2: Take an appropriate amount of KH550 and add it to the solution described in Step S1, and then stir in a water bath at 60 °C for 6 h to obtain the modified waterborne polyurethane KH-PU;
[0013] Step S3: Let KH-PU stand until room temperature.
[0014] Furthermore, the preparation method of the hydrophobic layer stock solution is as follows:
[0015] Step R1: Take an appropriate amount of KH-PU and dilute it with the same mass of deionized water. Add 1 mL of organosilicon defoamer and stir for 20 min;
[0016] Step R2: Respectively take 30 mg, 40 mg, and 50 mg of FS-SiO₂ powder and add them to the diluted KH-PU solution described in Step R1;
[0017] Step R3: After stirring the solution described in Step R2 at room temperature for 12 h, ultrasonicate it at a power of 100 W for 10 min to obtain the hydrophobic layer stock solution.
[0018] Furthermore, for a polymer hydrophobic coating formed on a nylon 6 substrate and based on the surface of an EVOH hydrogen barrier coating, its coating assembly method is as follows:
[0019] Step T1: Ultrasonically clean the nylon 6 substrate three times with deionized water and ethanol respectively, and leave it to dry at room temperature for 48 h;
[0020] Step T2: Place the nylon 6 substrate in Step T1 on a flat tabletop, and evenly brush a layer of nylon treatment agent on it to form an adhesion layer on the nylon surface, and air-dry at room temperature for 30 min;
[0021] Step T3: Pour an appropriate volume of the hydrogen barrier layer stock solution evenly on the adhesion layer described in Step T2, vacuum dry at 35 °C for 6 h, and cure at room temperature for 36 h after taking it out;
[0022] Step T4: Take an appropriate volume of the hydrophobic layer stock solution and pour it evenly on the hydrogen barrier layer described in Step T3, vacuum dry at 45 °C for 4 h to form a hydrophobic layer on the nylon surface.
[0023] Further, the main components of the nylon treatment agent described in Step T2 are resin and curing agent, and the resin is one or more of epoxy resin, acrylic resin or bisphenol A resin.
[0024] Further, the thickness of the adhesion layer described in Step T2 is 30 - 50 μm.
[0025] Further, the thickness of the hydrogen barrier layer described in Step T3 is 150 - 200 μm.
[0026] Further, the thickness of the hydrophobic layer described in Step T4 is 100 - 150 μm.
[0027] The present invention prepares a polymer coating with hydrophobic properties on the surface of the EVOH hydrogen barrier coating. The coating mainly consists of waterborne polyurethane, and by introducing nano-silica and trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane, the surface roughness of the coating is increased and the surface energy is reduced. At the same time, a silane coupling agent is used to combine the waterborne polyurethane with the hydrophobic component, thereby realizing the hydrophobic effect on the coating surface. Compared with the prior art, the method of the present invention has the following advantages and outstanding effects: the coating preparation method is simple, the coating can be dried at 45 °C without too high temperature; the coating thickness can be controlled by controlling the pouring amount of the mixed solution; the coating surface has strong hydrophobicity and can be used as an effective barrier between water molecules and the hydrogen barrier layer. Description of the Drawings
[0028] Figure 1 It is the three-dimensional surface topography of the KH-PU / FS-SiO2 composite coating with 30 mg FS-SiO2 powder added in Example 1 under an atomic force microscope (AFM). Detailed Embodiments
[0029] The following further describes the present invention with reference to the drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.
[0030] Example 1: Composite Coating with 30 mg FS-SiO2 Powder Added
[0031] First, prepare trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane-modified silica (FS-SiO2), and the specific steps are as follows:
[0032] Step G1, 200 mg of nano-SiO2 is ultrasonically dispersed in 200 mL of absolute ethanol at a concentration of 1 mg / mL, and ultrasonically treated for 1.5 h at room temperature to make it fully dispersed;
[0033] Step G2, use a pipette to measure 1 mL of FS1710, and then slowly drop it into the continuously stirred nano-SiO2 dispersion, and stir at room temperature for 24 h;
[0034] Step G3, filter and wash the product of Step G2 three times with absolute ethanol, and then vacuum dry the product at 60 °C for 6 h;
[0035] Step G4, grind the product of G3 and sieve it through a 200-mesh sieve to obtain the final product FS-SiO2 powder.
[0036] Secondly, prepare silane-coupling-agent-modified waterborne polyurethane (KH-PU), and the specific steps are as follows:
[0037] Step S1, take 20 g of WPU, add 20 g of deionized water for dilution, place the solution on a magnetic stirrer, and stir at room temperature for 20 min;
[0038] Step S2, take 4 mL of KH550 and add it to the solution described in Step S1, and then stir it in a water bath at 60 °C for 6 h to obtain the modified waterborne polyurethane KH-PU;
[0039] Step S3, let KH-PU stand to room temperature.
[0040] Then, prepare a hydrophobic layer coating stock solution containing 30 mg of FS-SiO2 powder, and the specific steps are as follows:
[0041] Step R1, take 20 g of KH-PU and add 20 g of deionized water for dilution, add 1 mL of silicone defoamer and stir for 20 min;
[0042] Step R2, take 30 mg of FS-SiO2 powder and add it to the diluted KH-PU solution described in Step R1;
[0043] Step R3, stir the solution described in Step R2 at room temperature for 12 h, and then ultrasonically treat it at a power of 100 W for 10 min to obtain the hydrophobic layer stock solution.
[0044] Finally, coat a composite coating on a nylon 6 substrate, and the specific steps are as follows:
[0045] Step T1: Ultrasonically clean the nylon 6 substrate three times with deionized water and ethanol respectively, and leave it to dry at room temperature for 48 h;
[0046] Step T2: Place the nylon 6 substrate obtained in Step T1 on a flat tabletop, and evenly brush a layer of nylon treatment agent on it to form an adhesion layer on the nylon surface. Air-dry it at room temperature for 30 min, and the thickness of the adhesion layer is 30 - 50 μm;
[0047] Step T3: Pour an appropriate volume of the hydrogen barrier layer stock solution evenly on the adhesion layer described in Step T2, and vacuum-dry it at 35 °C for 6 h. After taking it out, cure it at room temperature for 36 h to form a barrier layer on the nylon surface, and the thickness of the barrier layer is 150 - 200 μm;
[0048] Step T4: Take an appropriate volume of the hydrophobic layer stock solution and pour it evenly on the hydrogen barrier layer described in Step T3, and vacuum-dry it at 45 °C for 4 h to form a hydrophobic layer on the nylon surface, and the thickness of the hydrophobic layer is 100 - 150 μm.
[0049] Please refer to Figure 1 , the three-dimensional morphology and roughness of the surface of the KH-PU / FS-SiO2 composite coating added with 30 mg of FS-SiO2 powder were characterized by atomic force microscopy. It can be observed from the figure that the surface of the coating is rough because the addition of FS-SiO2 powder will introduce microscale inhomogeneities, resulting in an increase in the surface roughness of the coating.
[0050] Example 2: Composite coating added with 40 mg of FS-SiO2 powder
[0051] Same as Example 1, the difference is that the addition amount of the FS-SiO2 powder described in Step R2 is 40 mg.
[0052] It should be noted that the present invention includes but is not limited to the above-mentioned embodiments. Modifications and improvements made based on the concept of the present invention all fall within the protection scope of the present invention.
Claims
1. A polymer hydrophobic coating on the surface of an EVOH hydrogen barrier coating and its preparation method, characterized in that, The coating includes a substrate, an adhesion layer, a hydrogen barrier layer, and a hydrophobic layer arranged in sequence.
2. A polymer hydrophobic coating based on the surface of an EVOH hydrogen barrier coating and its preparation method according to claim 1, wherein the substrate is nylon 6.
3. A polymer hydrophobic coating based on the surface of an EVOH hydrogen barrier coating and its preparation method according to claim 1, wherein the adhesion layer is a nylon treatment agent, and the main components are resin and curing agent, and the resin is one or more of epoxy resin, acrylic resin, or bisphenol A resin.
4. A polymer hydrophobic coating based on the surface of an EVOH hydrogen barrier coating and its preparation method according to claim 1, wherein the coating stock solution of the hydrogen barrier layer is composed of a composite of ethylene-vinyl alcohol copolymer (EVOH) and polyethyleneimine (PEI) modified graphene oxide (GO).
5. A polymer hydrophobic coating based on the surface of an EVOH hydrogen barrier coating and its preparation method according to claim 1, wherein the coating stock solution of the hydrophobic layer uses waterborne polyurethane (WPU) modified with silane coupling agent (KH550) as the main raw material, marked as KH-PU; trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane (FS1710) modified nano-silica (SiO2) is used as a filler for composite, and the modified filler is denoted as FS-SiO2, and the composite coating is marked as KH-PU / FS-SiO2.
6. The preparation method of the filler FS-SiO2 according to claim 5 is as follows: Step G1, ultrasonically disperse nano-SiO2 in absolute ethanol at a concentration of 1 mg / mL, and ultrasonically disperse it at room temperature for 1.5 h to make it fully dispersed; Step G2, use a pipette to measure an appropriate amount of FS1710, and then slowly drop it into the continuously stirred nano-SiO2 dispersion, and stir at room temperature for 24 h; Step G3, filter and wash the product of Step G2 with absolute ethanol three times, and then vacuum dry the product at 60 °C for 6 h; Step G4, grind the product of G3 and sieve it through a 200-mesh sieve to obtain the final product FS-SiO2 powder.
7. The preparation method of the modified waterborne polyurethane (KH-PU) according to claim 5 is as follows: Step S1, take an appropriate amount of WPU and dilute it with the same mass of deionized water, place the solution on a magnetic stirrer, and stir at room temperature for 20 min; Step S2, take an appropriate amount of KH550 and add it to the solution described in Step S1, and then stir it in a water bath at 60 °C for 6 h to obtain the modified waterborne polyurethane KH-PU; Step S3, let KH-PU stand until room temperature.
8. A polymer hydrophobic coating based on the surface of an EVOH hydrogen barrier coating and its preparation method according to claim 1, wherein the preparation method of the hydrophobic layer stock solution is as follows: Step R1, take an appropriate amount of KH-PU and dilute it with the same mass of deionized water, add 1 mL of silicone defoamer to the solution, and stir at room temperature for 20 min; Step R2, take 30 mg, 40 mg, and 50 mg of FS-SiO2 powder respectively and add them to the diluted KH-PU solution described in Step R1; Step R3: After stirring the solution described in Step R2 at room temperature for 12 h, ultrasonicate it at a power of 100 W for 10 min to obtain the hydrophobic layer stock solution.
9. A polymer hydrophobic coating on the surface of an EVOH hydrogen barrier coating and a preparation method thereof according to claim 1, characterized in that, The steps for assembling the substrate, adhesion layer, hydrogen barrier layer, and hydrophobic layer are as follows: Step T1: Ultrasonically clean the nylon 6 substrate three times each with deionized water and ethanol, and leave it to dry at room temperature for 48 h. Step T2: Place the nylon 6 substrate from Step T1 on a flat tabletop, and evenly brush a layer of nylon treatment agent on it to form an adhesion layer on the nylon surface, and dry it at room temperature for 30 min. Step T3: Pour an appropriate volume of the hydrogen barrier layer stock solution evenly onto the adhesion layer described in Step T2, vacuum dry it at 35 °C for 6 h, take it out and cure it at room temperature for 36 h. The thickness of the hydrogen barrier layer is 150 - 200 μm. Step T4: Take an appropriate volume of the hydrophobic layer stock solution and pour it evenly onto the hydrogen barrier layer described in Step T3, vacuum dry it at 45 °C for 4 h to form a hydrophobic layer on the nylon surface. The thickness of the hydrophobic layer is 100 - 150 μm.