CN114471191A

CN114471191A - Anti-adhesion coating composite film with high moisture permeability and preparation method thereof

Info

Publication number: CN114471191A
Application number: CN202111521109.6A
Authority: CN
Inventors: 张立志; 杨兵; 梁才航
Original assignee: South China University of Technology SCUT; Guilin University of Electronic Technology
Current assignee: South China University of Technology SCUT; Guilin University of Electronic Technology
Priority date: 2021-12-13
Filing date: 2021-12-13
Publication date: 2022-05-13
Anticipated expiration: 2041-12-13
Also published as: CN114471191B

Abstract

The invention discloses a high moisture permeable anti-adhesion coating composite film and a preparation method thereof; the anti-adhesion coating composite membrane with high moisture permeability is formed by coating an active cortex layer on a porous supporting layer membrane material; the active cortex is coated in an interface deposition mode and grafted on the porous supporting layer by intermolecular force and hydrogen bonds to form an asymmetric structure with a compact surface. The active cortex component is formed by copolymerizing a vinyl silane coupling agent and N-vinyl pyrrolidone NVP, and then performing hydrolytic condensation to form an active molecular structure of PVP-polyvinyl siloxane. The composite film well solves the problem that the existing high-moisture-permeability film materials are adhered together and mass production cannot be realized, namely the problem of contradiction between the moisture permeability and the adhesion of the film is effectively solved. The composite film has high moisture permeability, low adhesion, low production cost and simple production method, and is a promising film material.

Description

Anti-adhesion coating composite film with high moisture permeability and preparation method thereof

Technical Field

The invention relates to the field of air dehumidification and air conditioner total heat recovery, in particular to a high-moisture-permeability anti-adhesion coating composite film and a preparation method thereof.

Background

Along with the continuous development of the modern construction of China, the problem of building energy consumption is gradually shown. The building energy consumption refers to energy consumed by civil buildings in the using process, and mainly comprises energy consumed by heating, air conditioning, ventilation, hot water supply, illumination and the like. According to the relevant data, 30% of the total energy consumption of China is the energy consumption of buildings at present. More than 80% of the existing buildings in China have high energy consumption; it is worth noting that a large part of the total building energy consumption is air conditioner energy consumption, the energy consumption of a common central air conditioner accounts for about 50% of the total building energy consumption, and can reach more than 65% in markets and comprehensive buildings.

In air conditioning systems, a membrane total heat exchanger is an air-air energy recovery device which has been developed rapidly in recent years. Compared with other traditional heat exchangers, the membrane type total heat exchanger can simultaneously carry out heat and moisture transfer. The advantages of low energy consumption, continuous operation, no cross contamination, obvious heat and humidity recovery effect and the like of the membrane type total heat exchanger gradually become research hotspots in recent years. The moisture permeable membrane is a key factor determining the performance of the membrane type total heat exchanger, and fresh air and exhaust air exchange latent heat and sensible heat at the interface of the moisture permeable membrane with high selective permeability.

In order to prevent cross contamination of fresh air and exhaust air, the used membrane material should be a compact moisture permeable membrane impermeable to harmful gases such as carbon dioxide. For the traditional compact film, the application of the compact film in the fields of air dehumidification and air conditioning total heat recovery is limited due to the defects of large mass transfer resistance, unobvious moisture permeability effect and the like. For a composite membrane with a compact and selective permeability skin layer coated on a porous support layer membrane material, the thickness of the compact skin layer accounts for 5% -10% of the total thickness of the membrane, so the mass transfer resistance of the composite membrane is far smaller than that of the compact membrane under the condition of the same thickness. The composite film based on the composite film not only has high moisture permeation efficiency, but also is impermeable to harmful gases such as carbon dioxide and the like. The composite films in the current market have a common problem that the prepared finished films are often adhered together on the premise of ensuring higher moisture permeability, and the moisture permeability of the finished films is greatly reduced on the premise of ensuring that the finished films are not adhered. This makes it difficult to compromise between high moisture permeability and low blocking of the film.

At present, the composite membrane with high moisture permeability is almost adhered together, so that the industrial mass production cannot be realized. In the document entitled Synthesis and chromatography of PVA/LiCl blend Membrane for air de-husbandization published in Journal of Membrane Science in 2008, a composite Membrane with PVA/LiCl as an active compact skin layer is invented, which has high moisture permeability, but the reaction temperature required by the process flow is high, the reaction time is long, and the prepared composite Membrane is easy to be adhered together, so that the industrial mass production cannot be realized. Therefore, the development of a high moisture-permeable anti-adhesion coating composite film is urgent for effectively reducing air conditioning load and building energy consumption.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the invention aims to provide a high moisture-permeable anti-adhesion coating composite film and a preparation method thereof. The composite film prepared by the invention not only has high moisture permeability effect, but also has low viscosity.

The purpose of the invention is realized by the following technical scheme:

a highly moisture permeable anti-adhesion coating composite membrane, coating a layer of active cortex on a porous supporting layer membrane material; the active cortex is coated in an interface deposition mode and grafted on the porous supporting layer by intermolecular force and hydrogen bonds to form an asymmetric structure with a compact surface.

Preferably, the material of the porous support layer is one of polyvinylidene fluoride, polyethylene and polypropylene.

Preferably, the active skin layer component is an active molecular structure of PVP-polyvinyl siloxane formed by copolymerizing a vinyl silane coupling agent and N-vinyl pyrrolidone NVP, and then performing hydrolytic condensation.

Preferably, the surface roughness of the high moisture-permeable anti-blocking coating composite film is 10-35 nm; the surface contact angle of the high moisture-permeable anti-blocking coating composite film is 50-80 degrees; the thickness of the compact active cortex of the high moisture permeable anti-adhesion coating composite film is 2-5 mu m.

The preparation method of the anti-adhesion coating composite film with high moisture permeability comprises the following steps:

(1) adding a vinyl silane coupling agent, N-vinyl pyrrolidone (NVP) and an initiator into an organic mixed solvent, and stirring for 20-24 hours at 40-60 ℃ to obtain a pre-copolymerization mixed solution;

(2) under the condition of stirring at 40-60 ℃, dropwise adding deionized water and a catalyst into the pre-copolymerization mixed solution, stirring for 12-18 h, standing and defoaming to obtain an active cortex solution;

(3) and coating the active cortex solution on a porous supporting layer membrane material, and crosslinking and drying at 60-80 ℃ for 1-2 h to obtain the high-moisture-permeability anti-adhesion coating composite membrane.

Preferably, the organic mixed solvent, deionized water, initiator, catalyst, N-vinyl pyrrolidone NVP, and vinyl silane coupling agent are used in an amount of 100% by mass: 70-83 wt% of organic mixed solvent, 0.5-1 wt% of deionized water, 0.1-0.3 wt% of initiator, 0.15-0.2 wt% of catalyst, and the balance of N-vinyl pyrrolidone NVP and vinyl silane coupling agent.

Preferably, the catalyst in the step (2) is a hydrochloric acid solution with the weight percent of 36-38%;

preferably, the standing and defoaming time is 15-30 min.

Preferably, the mass ratio of the vinyl silane coupling agent to the N-vinyl pyrrolidone NVP in the step (1) is as follows: 1:1 to 5: 2.

Preferably, the organic mixed solvent in the step (1) is n-propanol and butanone, wherein the mass ratio of the n-propanol to the butanone is 1: 1-5: 1.

Preferably, the initiator in the step (1) is azobisisobutyronitrile AIBN;

preferably, the vinyl silane coupling agent in the step (1) is one of vinyl trimethoxy silane, vinyl triethoxy silane and vinyl triisopropoxy silane.

The compact active cortex is the key for determining whether the composite membrane has selective permeability, and the thickness of the compact active cortex is inversely proportional to the moisture permeation efficiency, namely, the thicker the compact active cortex is, the larger the resistance for transferring water vapor is, and the lower the moisture permeation efficiency is; conversely, the thinner the compact active skin layer is, the smaller the resistance to water vapor transmission is, and the higher the moisture permeation efficiency is. Because the water vapor transmission between the dry air and the wet air is that the water vapor is firstly absorbed to the surface of the membrane and then is diffused among the membranes, the compact active skin layer has hydrophilicity, and the stronger the hydrophilicity is, the more obvious the water vapor is absorbed to the surface of the membrane; conversely, the less hydrophilic, the less pronounced the adsorption of water vapor to the membrane surface. Therefore, the control of the thickness and hydrophilicity of the compact skin layer plays an important role in the moisture permeability of the composite membrane.

Compared with the prior art, the invention has the following beneficial effects:

(1) the skin layer component of the composite membrane is modified on the basis of only polysiloxane, so that the contact angle of the active skin layer is lower, the hydrophilicity is better, and the moisture permeability efficiency is higher;

(2) compared with the prior art, the compact active skin layer of the composite membrane has better hydrophilicity, lower adhesion, low temperature requirement, low equipment cost and easy operation;

(3) the composite film has a very thin skin layer which can reach 2-5 mu m, and the moisture permeability efficiency is greatly improved;

(4) the composite film of the present invention has a lower roughness of the film surface than that of the prior art and a smoother film surface.

Drawings

FIG. 1 is a reaction mechanism diagram of an active dense skin layer in the present invention.

FIG. 2 is an IR spectrum of example 1, example 2 and comparative example 1 of the present invention.

FIG. 3a is an SEM surface view at 2000 times magnification of PVDF porous support layer membrane material used in the examples of the present invention.

FIG. 3b is an SEM cross-sectional view at 2000 times magnification of PVDF porous support layer membrane material used in the examples of the present invention.

FIG. 4a is a SEM surface image of the composite membrane of example 1 at 5000 magnification.

FIG. 4b is a cross-sectional view of the composite membrane of example 1 at 1000 times magnification.

FIG. 5a is a surface elemental analysis chart of polyvinylidene fluoride in example 1 of the present invention.

FIG. 5b is a surface elemental analysis chart of the composite film in example 1 of the present invention.

FIG. 6a is an atomic mechanical microscope photograph of polyvinylidene fluoride as the porous support layer of example 1 of the present invention.

FIG. 6b is an atomic mechanical microscope image of the composite film of example 1 of the present invention.

FIG. 6c is an atomic mechanical microscope image of a commonly used commercially available membrane.

FIG. 7 is a flow chart for testing the moisture permeability of the composite membrane of the present invention.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.

FIG. 1 is a reaction mechanism diagram of an active compact skin layer in the present invention, that is, under the action of an initiator, N-vinyl pyrrolidone NVP and a vinyl silane coupling agent are first reacted, and C ═ C of the N-vinyl pyrrolidone NVP are opened and subjected to a copolymerization reaction; secondly, the vinyl silane coupling agent is hydrolyzed under the acidic condition to generate-Si-OH; finally, condensation reaction is carried out to form an active high molecular structure connected by-Si-O-Si-.

The moisture permeability of the composite membrane is tested according to the flow chart of FIG. 7; the method comprises the following specific steps:

in the figure, two air flows are provided, one air flow simulates fresh air through humidification and temperature rise, and the moisture content of the air at a fresh air inlet is controlled to be 0.02kg/kg, and the temperature is controlled to be 35 ℃; the other air flow is cooled and dehumidified by an electronic dehumidifier to simulate air exhaust, the moisture content of the air at an air exhaust inlet is controlled to be 0.01kg/kg, and the temperature is controlled to be 25 ℃. The temperature and humidity changes of fresh air and exhaust air are read by four temperature and humidity displays, and the fresh air and the exhaust air are arranged on a plate-like heat exchangerIs arranged in the cavity shell for heat and mass exchange. The temperature and humidity display value can be converted into the moisture content of air by calculation, so that the moisture permeability efficiency of the composite film is calculated. In order to simplify the calculation of the moisture permeability of the composite membrane and control the air flow rate of fresh air and exhaust air to be consistent, the calculation formula of the moisture permeability efficiency of the composite membrane can be simplified into

Subscripts "f", "e" indicate fresh air and exhaust air, respectively, and subscripts "i", "o" indicate air inlet and outlet. Omega is the moisture content of air, and epsilon is the moisture permeation efficiency of the composite film. The volume flow of the two air flows is controlled to be 0.06m in the experimental test process³/h。

The preparation of the polyvinylidene fluoride PVDF porous support layer membrane used in the embodiment is prepared by a non-solvent phase-induced transformation method, and the specific preparation process is as follows: (1) dissolving 10 wt% of PVDF in 87.2 wt% of N-N dimethylformamide solvent, adding 2.8 wt% of pore-forming agent polyvinyl alcohol PEG2000, stirring for 12-16 h at 65 ℃, (2) standing and defoaming the casting solution obtained in (1) for 0.5-1 h at room temperature, (3) flatly placing a clean glass plate on a film scraping machine, pouring a proper amount of casting solution on the glass plate, controlling the thickness of the film scraping machine to be 100 mu m, completing the film scraping step, (4) taking down the glass plate with the film scraped, placing the glass plate in a coagulating bath at room temperature, and allowing the film to form and be separated from the glass plate, (5) soaking the separated film in clean water for 2 days, and changing water once every 12h to remove the solvent DMF, (6) airing the film in (5) at room temperature to obtain the PVDF porous support film.

Polypropylene PP porous support layer membrane, polyethylene PE porous support layer membrane materials presented in the examples were purchased by the industry. Further, comparative example 1 is a commonly available film used, and its composition is a VTMO/PP composite film.

Example 1

(1) Weighing 6 parts of vinyltrimethoxysilane VTMO, 6 parts of N-vinyl pyrrolidone NVP and 0.1 part of azobisisobutyronitrile AIBN in 44 parts of an organic mixed solvent of N-propanol and butanone, wherein the ratio of the N-propanol to the butanone is 2: 1, stirring for 20 hours at the temperature of 60 ℃ to obtain a pre-copolymerization mixed solution;

(2) dropwise adding 0.3 part of deionized water and 0.1 part of 36-38 wt% hydrochloric acid solution into the mixed solution obtained in the step (1), stirring at 60 ℃ for 12 hours, and standing and defoaming at room temperature for 30min to obtain a PVP-VTMO active molecular cortex solution;

(3) and (3) placing the polyvinylidene fluoride PVDF porous support layer membrane with the thickness of about 25 mu m on a flat glass plate, uniformly coating the active skin layer solution obtained in the step (2) on the surface of one side of the PVDF, placing the coated composite membrane in a vacuum oven at 80 ℃ for crosslinking for 1h, and drying to obtain the PVP-VTMO/PVDF composite membrane.

The thickness of the ultrathin compact skin layer of the composite film prepared by adopting the technical scheme is about 2-3 mu m, the moisture permeation efficiency is 46.5%, the surface contact angle of the finished film is 54 degrees, the surface average roughness Ra of the finished film is 10.5nm, and the finished film cannot be adhered.

Example 2

(1) Weighing 6 parts of vinyltrimethoxysilane VTMO, 4 parts of N-vinyl pyrrolidone NVP and 0.08 part of azobisisobutyronitrile AIBN in 44 parts of an organic mixed solvent of N-propanol and butanone, wherein the proportion of the N-propanol to the butanone is 5:2, stirring for 24 hours at the temperature of 40 ℃ to obtain a pre-copolymerization mixed solution;

(2) dropwise adding 0.24 part of deionized water and 0.08 part of 36-38 wt% hydrochloric acid solution into the mixed solution obtained in the step (1), stirring for 18 hours at the temperature of 40 ℃, standing and defoaming for 30min at room temperature to obtain a PVP-VTMO active molecular cortex solution;

The thickness of the ultrathin compact skin layer of the composite film prepared by adopting the technical scheme is about 2-3 mu m, the moisture permeation efficiency is 42.7%, the surface contact angle of the finished film is 73 degrees, the surface average roughness Ra of the finished film is 34.7nm, and the finished film cannot be adhered.

Example 3

(1) Weighing 6 parts of vinyltrimethoxysilane VTMO, 6 parts of N-vinyl pyrrolidone NVP and 0.1 part of azobisisobutyronitrile AIBN in 44 parts of an organic mixed solvent of N-propanol and butanone, wherein the proportion of the N-propanol to the butanone is 3: 1, stirring for 20 hours at the temperature of 60 ℃ to obtain a pre-copolymerization mixed solution;

(3) and (3) placing the polypropylene PP porous support layer film with the thickness of about 28 micrometers on a flat glass plate, uniformly coating the active skin layer solution obtained in the step (2) on one side surface of the PP, placing the coated composite film in a vacuum oven at 80 ℃ for crosslinking for 1h, and drying to obtain the PVP-VTMO/PP composite film.

The thickness of the ultrathin compact skin layer of the composite film prepared by adopting the technical scheme is about 4 mu m, the moisture permeation efficiency is 44.8 percent, the contact angle of the surface of the finished film is 62 degrees, the average roughness Ra of the surface of the finished film is 24.5nm, and the finished film cannot be adhered.

Example 4

(1) Weighing 6 parts of vinyltriethoxysilane, 3 parts of N-vinylpyrrolidone NVP and 0.08 part of azobisisobutyronitrile AIBN in 44 parts of an organic mixed solvent of N-propanol and butanone, wherein the ratio of N-propanol to butanone is 4: 1, stirring for 22 hours at the temperature of 50 ℃ to obtain a pre-copolymerization mixed solution;

(2) dropwise adding 0.24 part of deionized water and 0.08 part of 36-38 wt% hydrochloric acid solution into the mixed solution obtained in the step (1), stirring for 15 hours at the temperature of 50 ℃, standing and defoaming for 30min at room temperature to obtain a PVP-vinyltriethoxysilane active molecular cortex solution;

(3) and (3) placing the polyvinylidene fluoride PVDF porous support layer film with the thickness of about 25 micrometers on a flat glass plate, uniformly coating the active skin layer solution obtained in the step (2) on the surface of one side of the PVDF, placing the coated composite film in a vacuum oven at the temperature of 60 ℃ for crosslinking for 1 hour, and drying to obtain the PVP-vinyltriethoxysilane/PVDF composite film.

The thickness of the ultrathin compact skin layer of the composite film prepared by adopting the technical scheme is about 3-4 microns, the moisture permeability efficiency is 41.9%, the contact angle of the surface of the finished film is 68 degrees, and the finished film cannot be adhered.

Example 5

(1) Weighing 6 parts of vinyl triisopropoxysilane, 2.4 parts of N-vinyl pyrrolidone NVP and 0.06 part of azobisisobutyronitrile AIBN in 44 parts of an organic mixed solvent of N-propanol and butanone, wherein the proportion of the N-propanol to the butanone is 5:1, stirring for 22 hours at the temperature of 50 ℃ to obtain a pre-copolymerization mixed solution;

(3) and (3) placing the polyethylene PE porous support layer film with the thickness of about 26 microns on a flat glass plate, uniformly coating the active skin layer solution obtained in the step (2) on the surface of one side of the PE, placing the coated composite film in a vacuum oven at 70 ℃ for crosslinking for 1h, and drying to obtain the PVP-VTMO/PE composite film.

The thickness of the ultrathin compact skin layer of the composite film prepared by adopting the technical scheme is about 3-5 microns, the moisture permeability efficiency is 42.1 percent, the contact angle of the surface of the finished film is 77 degrees, and the finished film cannot be adhered.

Comparative example 1

(1) Weighing 6 parts of vinyl trimethoxy silane VTMO in 44 parts of an organic mixed solvent of n-propanol and butanone, wherein the proportion of the n-propanol to the butanone is 2: 1, stirring for 24 hours at the temperature of 60 ℃ to obtain a VTMO active cortex solution.

(2) And (2) placing a polypropylene PP porous support layer film with the thickness of about 28 micrometers on a flat glass plate, uniformly coating the active skin layer solution obtained in the step (1) on one side surface of PP, placing the coated composite film in a vacuum oven at 80 ℃ for crosslinking for 1h, and drying to obtain the VTMO/PP composite film.

The thickness of the ultrathin compact skin layer of the composite film prepared by adopting the technical scheme is about 4 mu m, the moisture permeation efficiency is 41.5 percent, the contact angle of the surface of the finished film is 92 degrees, the average roughness Ra of the surface of the finished film is 24.4nm, and the finished film cannot be adhered.

Comparative example 2

(1) Weighing 6 parts of vinyl trimethoxy silane VTMO in 44 parts of an organic mixed solvent of n-propanol and butanone, wherein the proportion of the n-propanol to the butanone is 5:1, stirring for 24 hours at the temperature of 40 ℃ to obtain a VTMO active cortex solution.

(2) And (2) placing the polyvinylidene fluoride PVDF porous support layer film with the thickness of about 25 mu m on a flat glass plate, uniformly coating the active skin layer solution obtained in the step (1) on one side surface of the PVDF, placing the coated composite film in a vacuum oven at 80 ℃ for crosslinking for 1h, and drying to obtain the VTMO/PVDF composite film.

The thickness of the ultrathin compact skin layer of the composite film prepared by adopting the technical scheme is about 5.3 mu m, the moisture permeation efficiency is 43 percent, the contact angle of the surface of the finished film is 83 degrees, the average roughness Ra of the surface of the finished film is 32.8nm, and the finished film cannot be adhered.

Comparative example 3

(1) Weighing 8 parts of polyvinyl alcohol PVA in 92 parts of deionized water, and heating and stirring at 90 ℃ for 2 hours; then 4 parts of L-malic acid, 0.1 part of glacial acetic acid and 2.5 parts of hygroscopic metal salt lithium chloride are added, stirred for 2 hours at the temperature of 70 ℃, cooled and kept stand for 30 minutes.

(2) And (2) placing the polyvinylidene fluoride PVDF porous support layer film with the thickness of about 25 mu m on a flat glass plate, uniformly coating the active skin layer solution obtained in the step (1) on one side surface of the PVDF, placing the coated composite film in a vacuum oven at 100 ℃ for crosslinking for 1h, and drying for 2h at 60 ℃ to obtain the PVA-LiCl/PVDF composite film.

The thickness of the ultrathin compact skin layer of the composite film prepared by adopting the technical scheme is about 15 mu m, the moisture permeability efficiency is 43.1 percent, the contact angle of the surface of the finished film is 52 degrees, and the finished film has an adhesion phenomenon.

FIG. 2 is an IR spectrum of example 1, example 2 and comparative example 1 of the present invention. Compared to the common commercial film, i.e. vinyltrimethoxysilane in comparative example 1, it is clear with the solution according to the invention that: example 1, example 2 at a wavenumber of 1600cm^-1The C-C vibration absorption peak has obvious weakening phenomenon, which proves that the copolymerization reaction effect is obvious; furthermore, in examples 1 and 2, the wave number is 1680cm^-1The C ═ O vibration absorption peak of NVP was observed, and the effect of copolymerization was also confirmed to be remarkable. In the three schemes, the wave number is 1100cm^-1In the vicinity, 844cm is an absorption peak of vibration of Si-O-Si bond^-1Is an absorption peak of Si-O bond, and proves that the vinyltrimethoxysilane is subjected to hydrolytic condensation reaction.

FIG. 3a is an SEM surface image of PVDF porous support layer membrane material used in the examples of the present invention magnified 2000 times, and it can be clearly seen from the surface image that PVDF membrane prepared by non-solvent phase inversion method has high porosity, and greatly reduces the diffusion resistance of water vapor on the porous support layer.

FIG. 3b is an SEM cross-sectional view of the PVDF porous supporting layer membrane material used in the embodiment of the invention, which is magnified 2000 times, and it can be clearly seen from the cross-sectional view that the PVDF membrane prepared by the non-solvent induced phase inversion method has finger-shaped through holes, which can improve the moisture permeability of the PVDF membrane.

FIG. 4a is a SEM surface image of the composite membrane of example 1 at 5000 magnification. Compared with the graph in FIG. 3a, a layer of compact active structure on the surface of the membrane can be clearly seen, and the successful preparation of the composite membrane is also proved, and the composite membrane not only has selective permeability, but also can well block CO₂And the harmful gases permeate the membrane material.

FIG. 4b is a cross-sectional view of the composite membrane of example 1 at 1000 times magnification. In contrast to fig. 3b, a thin dense skin layer can be seen in cross-section overlying the PVDF porous support layer, and it can also be seen that the finger holes are not plugged.

FIG. 5a is a surface elemental analysis chart of PVDF as polyvinylidene fluoride in example 1 of the present invention. Table 1 is a table of the elemental ratios of polyvinylidene fluoride in example 1 of the present invention; it was found that the PVDF had only C, O, F elements as the main component.

FIG. 5b is a surface elemental analysis chart of the composite film in example 1 of the present invention. Table 2 is a table of the elemental ratios of the composite films in example 1. The composite membrane of example 1, which was subjected to elemental analysis compared to fig. 5a and table 1, was greatly increased in N, O, Si elements, and the three elements were derived from the active cortex. The success of the preparation of the composite membrane of the invention is proved.

TABLE 1

Element(s)	wt％	Atomic percent
			C	38.84	49.99
O	1.50	1.45
			F	59.66	48.55
Total amount:	100.00	100.00

TABLE 2

Element(s)	wt％	Atomic percent
			C	39.63	50.90
N	2.02	2.22
			O	6.03	5.82
F	46.91	38.09
			Si	5.42	2.98
Total amount:	100.00	100.00

Fig. 6c is an atomic mechanical microscope image of comparative example 1, a commonly used commercial film.

In the three diagrams a, b and c of fig. 6, it can be clearly seen that the composite film of example 1 of the present invention has the smoothest surface and the least defects.

Table 3 shows the average roughness Ra and the root mean square average roughness Rq of the porous support layer polyvinylidene fluoride in example 1, the composite membrane in example 1, and the conventional commercially available membrane in comparative example 1. Lower Ra and Rq indicate smoother surface of the film, less defects. Table 3 it can be clearly seen that the composite film of the present invention has a smoother surface and fewer defects than the commonly used commercially available films.

TABLE 3

Table 4 summarizes the moisture permeability of the composite films of the examples and comparative examples of the present invention and whether the blocking phenomenon occurred in the composite films. The composite film prepared by the method has the advantages of lower contact angle, better hydrophilicity, smoother surface and higher moisture permeability efficiency, and the composite film prepared by the method can not be adhered together, so that the problem that the industrial high moisture permeability composite film is adhered together is effectively solved.

TABLE 4

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. The anti-adhesion coating composite membrane with high moisture permeability is characterized in that an active skin layer is coated on a porous supporting layer membrane material; the active skin layer is coated in an interface deposition mode and grafted on the porous supporting layer by intermolecular force and hydrogen bonds to form an asymmetric structure with a compact surface.

2. The composite film with high moisture permeability and anti-adhesion coating of claim 1, wherein the porous support layer film material is one of polyvinylidene fluoride, polyethylene and polypropylene.

3. The composite film with high moisture permeability and anti-adhesion coating of claim 1, wherein the active skin layer component is formed by copolymerization with N-vinyl pyrrolidone NVP by using a vinyl silane coupling agent, and then hydrolytic condensation to form the active molecular structure of PVP-polyvinyl siloxane.

4. The high moisture-permeable anti-blocking coating composite film according to claim 1, wherein the surface roughness of the high moisture-permeable anti-blocking coating composite film is 10-35 nm; the surface contact angle of the high moisture-permeable anti-adhesion coating composite film is 50-80 degrees; the thickness of the compact active cortex of the high moisture permeable anti-adhesion coating composite film is 2-5 mu m.

5. The method for preparing the high moisture-permeable anti-blocking coating composite film according to any one of claims 1 to 4, which comprises the following steps:

(2) under the stirring condition of 40-60 ℃, dropwise adding deionized water and a catalyst into the pre-copolymerization mixed solution, stirring for 12-18 hours, and standing for defoaming to obtain an active cortex solution;

6. The preparation method of the high moisture-permeable anti-blocking coating composite film according to claim 5, wherein the organic mixed solvent, deionized water, initiator, catalyst, N-vinylpyrrolidone (NVP) and vinyl silane coupling agent are used in an amount of 100% by mass: 70-83 wt% of organic mixed solvent, 0.5-1 wt% of deionized water, 0.1-0.3 wt% of initiator, 0.15-0.2 wt% of catalyst, and the balance of N-vinyl pyrrolidone NVP and vinyl silane coupling agent.

7. The method for preparing the high moisture-permeable anti-blocking coating composite film according to claim 5, wherein the catalyst in the step (2) is a hydrochloric acid solution with a concentration of 36-38 wt%; and the standing and defoaming time is 15-30 min.

8. The method for preparing the high moisture-permeable anti-blocking coating composite film according to claim 5, wherein the mass ratio of the vinyl silane coupling agent to the N-vinyl pyrrolidone NVP in the step (1) is as follows: 1:1 to 5: 2.

9. The preparation method of the high moisture-permeable anti-blocking coating composite film according to claim 5, wherein the organic mixed solvent in the step (1) is n-propanol and butanone, and the mass ratio of n-propanol to butanone is 1: 1-5: 1.

10. The method for preparing the high moisture-permeable anti-blocking coating composite film according to claim 5, wherein the initiator of step (1) is azobisisobutyronitrile AIBN; the vinyl silane coupling agent in the step (1) is one of vinyl trimethoxy silane, vinyl triethoxy silane and vinyl triisopropoxy silane.