Acrylic resin-based composite water-blocking film as well as preparation method and application thereof

Abstract

The invention provides an acrylic resin-based composite water-blocking film as well as a preparation method and application thereof, and belongs to the technical field of film materials. The preparation method comprises the following steps: placing an acrylic resin material on the surface of fiber cloth, and carrying out lamination treatment to enable a part of the acrylic resin material to be subjected to a cross-linking reaction to form gel, so as to obtain an acrylic prepreg base material; carrying out modification treatment on the inorganic oxide sol by adopting a coupling agent to obtain modified oxide sol; and coating the modified oxide sol on the surface of the acrylic prepreg base material, and sequentially carrying out defoaming and thermocuring to obtain the acrylic resin-based composite water-blocking film. The acrylic resin-based composite water-blocking film prepared by the method has excellent water-blocking performance.

Description

Technical Field

[0001] This invention relates to the field of membrane materials technology, and in particular to an acrylic resin-based composite water-blocking membrane, its preparation method, and its application. Background Technology

[0002] Water-blocking films are widely used in photovoltaic module encapsulation, moisture protection for electronic devices, and flexible displays. Photovoltaic modules, especially flexible and lightweight ones, have a particularly urgent need for high water-blocking performance. Traditional photovoltaic water-blocking films often employ a composite structure of a polymer film and an inorganic coating. The core process involves first preparing a fully cured polymer substrate, and then applying an inorganic coating to the substrate surface via magnetron sputtering or coating. However, water-blocking films prepared using this process exhibit poor water-blocking performance. Summary of the Invention

[0003] The purpose of this invention is to provide an acrylic resin-based composite water-blocking membrane, its preparation method, and its application. The acrylic resin-based composite water-blocking membrane prepared by the method of this invention has excellent water-blocking performance, as well as high mechanical strength and low defects in the barrier layer.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing an acrylic resin-based composite water-blocking membrane, comprising the following steps: An acrylic resin material is placed on the surface of a fiber cloth, and a lamination process is performed to cause a cross-linking reaction of some of the acrylic resin material to form a gel, thereby obtaining an acrylic prepreg substrate. Inorganic oxide sols were modified using coupling agents to obtain modified oxide sols. The modified oxide sol is coated on the surface of the acrylic prepreg substrate, and then degassed and heat-cured in sequence to obtain the acrylic resin-based composite water-blocking film.

[0005] Preferably, the acrylic resin material includes unmodified acrylic resin or modified acrylic resin, wherein the modified acrylic resin includes fluorosilicone modified acrylic resin, epoxy acrylic resin or polyurethane modified acrylic resin; the fiber cloth includes glass fiber cloth, wherein the glass fiber cloth has a specification of 50~200g / m². 2 The transmittance is ≥80% under light wavelength conditions of 380~1100nm; Based on the area of ​​the fiber cloth, the amount of acrylic resin material used is 50~600g / m². 2 ; The degree of curing of the acrylic prepreg substrate is 10-22%.

[0006] Preferably, the lamination process includes: evacuating the vacuum for 50-70 seconds to a vacuum degree of 20-200 Pa, applying pressure for 50-70 seconds to a pressure of 0.1-0.3 MPa, and laminating at a temperature of 155-165°C for 3.5-4.5 minutes; the thickness of the acrylic prepreg substrate is 100-350 μm.

[0007] Preferably, the inorganic oxide sol includes silica sol, alumina sol, or titanium dioxide sol; the precursor reagent used to prepare the inorganic oxide sol includes tetraethyl orthosilicate, aluminum isopropoxide, or tetrabutyl titanate; the solid content of the modified oxide sol is 7-20 wt%, and the viscosity is 20-150 mPa·s.

[0008] Preferably, the coating includes scraping, dipping, or spraying; The conditions for the scraping process include: the viscosity of the modified oxide sol is 50~150 mPa·s, the blade gap is 50~300 μm, and the scraping speed is 0.5~2 m / min; The conditions for dip coating include: the viscosity of the modified oxide sol is 40~60 mPa·s, and the immersion time is 5~10 min; The spraying conditions include: the viscosity of the modified oxide sol is 30~50 mPa·s, and the atomization pressure is 0.3~0.5 MPa.

[0009] Preferably, the degassing is vacuum degassing, wherein the vacuum degree of the vacuum degassing is -0.09 to -0.08 MPa, and the time is 10 to 20 minutes.

[0010] Preferably, the thermosetting is carried out under a pressure of 0.08~0.12MPa, and the thermosetting includes sequentially performing a first curing, a second curing, and a third curing; the temperature of the first curing is 40~60℃, and the holding time is 30~60min; the temperature of the second curing is 100~120℃, and the holding time is 60~120min; the temperature of the third curing is 140~170℃, and the holding time is 30~60min.

[0011] The present invention provides an acrylic resin-based composite water-blocking membrane prepared by the preparation method described above, comprising a fiber-reinforced acrylic resin composite membrane and inorganic oxides dispersed on the surface of the fiber-reinforced acrylic resin composite membrane; the fiber-reinforced acrylic resin composite membrane comprises an acrylic resin matrix and fibers dispersed in the acrylic resin matrix, wherein the inorganic oxides exist in the form of nanoparticles and a film.

[0012] Preferably, the nanoparticles have a particle size of 5-50 nm; and the acrylic resin-based composite water-blocking membrane has a thickness of 100-500 μm.

[0013] This invention provides the application of the acrylic resin-based composite water-blocking film described above in the encapsulation front plate of photovoltaic modules, the encapsulation back plate of photovoltaic modules, or the conductive substrate of perovskite photovoltaic cells.

[0014] Beneficial Effects: This invention places acrylic resin material on the surface of a fiber cloth, and through lamination, causes a partial cross-linking reaction of the acrylic resin material to form a gel, obtaining an acrylic prepreg substrate. An inorganic oxide sol is modified using a coupling agent to obtain a modified oxide sol. The modified oxide sol is coated onto the surface of the acrylic prepreg substrate, and then subjected to degassing and thermosetting to obtain the acrylic resin-based composite water-blocking membrane. The acrylic resin-based composite water-blocking membrane prepared by the method of this invention has excellent water-blocking performance. Specifically, this invention uses an acrylic prepreg substrate as the base material, coats it with a modified oxide sol as the initial component of the water vapor barrier layer, and obtains an acrylic resin-based composite water-blocking membrane through a simultaneous curing and molding process of acrylic prepreg and modified oxide sol. The integrally formed dense inorganic oxide layer endows it with high water vapor barrier performance, with a water vapor permeability as low as 0.3 g / m³. 2 • 24h. As the test results show, the water vapor transmission rate of the acrylic resin-based composite water-blocking membrane prepared in the embodiments of the present invention is 0.3~0.8 g / m. 2 • 24h, far lower than the water vapor permeability of traditional single resin membranes.

[0015] Furthermore, the acrylic resin-based composite water-blocking membrane of this invention retains the high light transmittance of the acrylic resin matrix, and the fiber cloth (such as glass fiber cloth) helps improve the mechanical properties of the acrylic resin-based composite water-blocking membrane, resulting in high biaxial tensile strength. Therefore, the acrylic resin-based composite water-blocking membrane of this invention has excellent water-blocking performance while also possessing high light transmittance and mechanical strength. Moreover, the acrylic resin-based composite water-blocking membrane prepared using the method of this invention also features low barrier layer defects. Attached Figure Description

[0016] Figure 1 This is a SEM image of the silica barrier layer in the acrylic resin-based composite water-blocking membrane of Example 1. Detailed Implementation

[0017] This invention provides a method for preparing an acrylic resin-based composite water-blocking membrane, comprising the following steps: An acrylic resin material is placed on the surface of a fiber cloth, and a lamination process is performed to cause a cross-linking reaction of some of the acrylic resin material to form a gel, thereby obtaining an acrylic prepreg substrate. Inorganic oxide sols were modified using coupling agents to obtain modified oxide sols. The modified oxide sol is coated on the surface of the acrylic prepreg substrate, and then degassed and heat-cured in sequence to obtain the acrylic resin-based composite water-blocking film.

[0018] In this invention, unless otherwise specified, all raw materials used are commercially available products known to those skilled in the art or prepared using methods known to those skilled in the art.

[0019] This invention involves placing an acrylic resin material on the surface of a fiber cloth, and then laminating it to cause a cross-linking reaction in a portion of the acrylic resin material to form a gel, thereby obtaining an acrylic prepreg substrate. In one embodiment of this invention, the fiber cloth includes a glass fiber cloth, and the glass fiber cloth can have a specification of 50~200 g / m². 2 Specifically, it can be 50g / m 2 100g / m 2 150g / m 2 Or 200g / m 2 The light transmittance of the glass fiber cloth is ≥80% and further ≥85% under light wavelength conditions of 380~1100nm.

[0020] In one embodiment of the present invention, the acrylic resin material includes unmodified acrylic resin or modified acrylic resin. The modified acrylic resin includes fluorosilicone-modified acrylic resin, epoxy acrylic resin, or polyurethane-modified acrylic resin. Specifically, the unmodified acrylic resin in this invention can be the high-transmittance acrylic powder resin in patent CN117701092A; the fluorosilicone-modified acrylic resin can be the fluorosilicone-modified acrylic resin in patent CN117700651A; the epoxy acrylic resin can be the epoxy acrylic powder coating resin in patent CN115651473A; and the polyurethane-modified acrylic resin can be the ultra-weather-resistant polyurethane-modified acrylic resin in patent CN118406196A. The present invention uses fluorosilicone-modified acrylic resin, epoxy acrylic resin, or polyurethane-modified acrylic resin, which combines the performance advantages of low water resistance of fluorosilicone resin, high strength of epoxy resin, and ultra-weather resistance of polyurethane resin, thus expanding the application scenarios of the acrylic resin-based composite water-blocking membrane. In one embodiment of the present invention, based on the area of ​​the fiber cloth, the amount of acrylic resin material used can be 50~600g / m². 2 Specifically, it can be 50g / m 2 100g / m 2 200g / m 2 250g / m 2 300g / m 2 350g / m 2 400g / m 2 500g / m2 Or 600g / m 2 In one embodiment of the present invention, the degree of curing of the acrylic prepreg substrate can be 10-22%, more specifically 18-22%; the degree of curing of the acrylic prepreg substrate in the present invention specifically refers to the percentage of the mass of the acrylic resin material undergoing the cross-linking reaction to the total mass of the acrylic resin material. In one embodiment of the present invention, the lamination process includes: vacuuming for 50-70 seconds to a vacuum degree of 20-200 Pa, applying pressure for 50-70 seconds to a pressure of 0.1-0.3 MPa, and laminating at a temperature of 155-165°C for 3.5-4.5 minutes; specifically in this embodiment, vacuuming for 1 minute to a vacuum degree of 50 Pa, applying pressure for 1 minute to a pressure of 0.1 MPa, and laminating at a temperature of 160°C for 4 minutes. In one embodiment of the present invention, the thickness of the acrylic prepreg substrate can be 100-350 μm, specifically 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, or 350 μm.

[0021] This invention uses a coupling agent to modify inorganic oxide sols to obtain modified oxide sols. In one embodiment of this invention, the inorganic oxide sol may include silica sol, alumina sol, or titanium dioxide sol. In another embodiment, the preparation method of the inorganic oxide sol includes the following steps: mixing a precursor reagent, ethanol, and water, and performing a hydrolysis-condensation reaction to obtain the inorganic oxide sol; the precursor reagent may include tetraethyl orthosilicate, aluminum isopropoxide, or tetrabutyl titanate, ultimately preparing silica sol, alumina sol, and titanium dioxide sol respectively; the volume ratio of ethanol to water can be 80~180:60, more specifically 100~150:60; the mass ratio of the precursor reagent to water can be 104:55~65, specifically 104:60; the temperature of the hydrolysis-condensation reaction can be 30~45℃, specifically 35℃; the time of the hydrolysis-condensation reaction can be 1~3h, specifically 1.5~2h. In one embodiment of the present invention, when the precursor reagent is tetraethyl orthosilicate, it is preferable to mix the precursor reagent with ethanol, then add water dropwise to the resulting material, and adjust the pH of the system to 2-3 to carry out a hydrolysis-condensation reaction; the pH value can further be 2-2.5; the reagent used to adjust the pH value can be hydrochloric acid, and the concentration of the hydrochloric acid can be 1 mol / L.

[0022] In one embodiment of the present invention, the coupling agent may include a silane coupling agent, an aluminate coupling agent, or a titanate coupling agent. Specifically, when the inorganic oxide sol is a silica sol, it is modified with a silane coupling agent to obtain a modified silica sol; when the inorganic oxide sol is an alumina sol, it is modified with an aluminate coupling agent to obtain a modified alumina sol; when the inorganic oxide sol is a titanium dioxide sol, it is modified with a silane coupling agent or a titanate coupling agent to obtain a modified titanium dioxide sol.

[0023] In one embodiment of the present invention, the silane coupling agent may include one or more of KH-550, KH-560, and KH-570, specifically KH-550, KH-560, or KH-570. In another embodiment of the present invention, the silane coupling agent is preferably pre-hydrolyzed before use to obtain a pre-hydrolyzed silane coupling agent; then, the pre-hydrolyzed silane coupling agent is used to modify the inorganic oxide sol. As one embodiment of the present invention, the method for pre-hydrolyzing the silane coupling agent includes the following steps: mixing the silane coupling agent, ethanol, and water; adjusting the pH of the resulting mixture to 2-4; and performing pre-hydrolysis to obtain the pre-hydrolyzed coupling agent; the volume ratio of ethanol to water can be 9:0.5-1.5, specifically 9:1; the mass ratio of the silane coupling agent to water can be 3.5:1.4-5.8, specifically 3.5:3; the pH value can further be 2.5-4; the reagent used to adjust the pH value can be dilute hydrochloric acid or glacial acetic acid, the concentration of the dilute hydrochloric acid can be 1 mol / L, and the glacial acetic acid can be used directly without dilution; the pre-hydrolysis temperature can be 20-30℃, specifically room temperature; and the time can be 0.5-2 h, specifically 1 h. The present invention, by pre-hydrolyzing the silane coupling agent, can generate silanol groups (Si-OH), which is beneficial for achieving the chemical bonding of inorganic and organic materials. In one embodiment of the present invention, the mass ratio of the precursor reagent (i.e., tetraethyl orthosilicate) to the silane coupling agent can be 100:2 to 5, and can further be 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5 or 100:5, specifically 104:3.5.

[0024] In one embodiment of the present invention, the aluminate coupling agent may include one or more of monoalkoxy aluminate coupling agents (such as DL-411), coordination aluminate coupling agents (such as DL-412), and long-chain alkyl aluminate coupling agents (such as LK-AL18), specifically DL-411. The aluminate coupling agent does not require pre-hydrolysis before use; it can be directly used to modify the alumina sol. In another embodiment of the present invention, the mass ratio of the precursor reagent (i.e., aluminum isopropoxide) to the aluminate coupling agent can be 400:0.8~1.2, specifically 400:1.

[0025] The present invention does not have any particular limitation on the specific type, method of use and amount of the titanate coupling agent. Any titanate coupling agent of a type known to those skilled in the art can be used and the method of use and amount known to those skilled in the art can be used.

[0026] In one embodiment of the present invention, the temperature of the modification treatment can be 50~70℃, specifically 55℃, 60℃ or 65℃; the time can be 0.5~2h, specifically 1.5h; the present invention preferably adds a coupling agent or a pre-hydrolyzed coupling agent dropwise to the oxide sol, after the dropwise addition is completed, the pH value is adjusted to 2~3 with dilute hydrochloric acid reagent, the temperature is raised to 50~70℃, and the modification treatment is carried out for 0.5~2h under stirring to obtain the modified oxide sol; the pH value can further be 2.5~3; the concentration of the dilute hydrochloric acid can be 1.0mol / L. In one embodiment of the present invention, the solid content of the modified oxide sol can be 7~20wt%, specifically 7wt%, 7.5wt%, 10wt%, 10.7wt%, 13wt%, 15wt%, 18wt%, or 20wt%, and the viscosity can be 20~150mPa·s, specifically 20mPa·s, 25mPa·s, 30mPa·s, 35mPa·s, 40mPa·s, 50mPa·s, 60mPa·s, 70mPa·s, 90mPa·s, 110mPa·s, 130mPa·s, or 150mPa·s. Unless otherwise specified, the viscosity of the modified oxide sol in the present invention specifically refers to the viscosity at a temperature of 25°C.

[0027] After obtaining the modified oxide sol, the present invention coats the modified oxide sol onto the surface of the acrylic prepreg substrate, and then sequentially degasses and heat-cures it to obtain the acrylic resin-based composite water-blocking film. As one embodiment of the present invention, the coating includes blade coating, dip coating, or spray coating, which will be described in detail below.

[0028] In one embodiment of the present invention, the conditions for the scraping process include: the viscosity of the modified oxide sol is 50~150 mPa·s, specifically 50 mPa·s, 60 mPa·s, 70 mPa·s, 90 mPa·s, 110 mPa·s, 130 mPa·s or 150 mPa·s; the blade gap is 50~300 μm, specifically 50 μm, 80 μm, 100 μm, 150 μm, 200 μm, 250 μm or 300 μm; and the scraping speed is 0.5~2 m / min, specifically 0.5 m / min, 1 m / min, 1.5 m / min or 2 m / min.

[0029] As one embodiment of the present invention, the conditions for dip coating include: the viscosity of the modified oxide sol is 40~60 mPa·s, specifically 40 mPa·s, 45 mPa·s, 50 mPa·s, 55 mPa·s or 60 mPa·s; the soaking time is 5~10 min, specifically 5 min, 8 min or 10 min.

[0030] In one embodiment of the present invention, the spraying conditions include: the viscosity of the modified oxide sol is 30~50 mPa·s, specifically 30 mPa·s, 35 mPa·s, 40 mPa·s, 45 mPa·s, or 50 mPa·s; and the atomization pressure is 0.3~0.5 MPa, specifically 0.3 MPa, 0.4 MPa, or 0.5 MPa. The spraying method used in this invention is suitable for preparing irregularly shaped water-blocking membranes.

[0031] In one embodiment of the present invention, the degassing is vacuum degassing, wherein the vacuum degree of the vacuum degassing is -0.09 to -0.08 MPa, and the time is 10 to 20 minutes.

[0032] In one embodiment of the present invention, the thermosetting is carried out under a pressure of 0.08~0.12MPa, specifically 0.1MPa; the thermosetting includes sequentially performing a first curing, a second curing, and a third curing. In another embodiment of the present invention, the temperature of the first curing is 40~60℃, specifically 40℃, 45℃, 50℃, 55℃, or 60℃; the holding time is 30~60min, specifically 30min, 35min, 40min, 45min, 50min, 55min, or 60min; performing the first curing under the above conditions is beneficial to promoting the preliminary film formation of the modified oxide sol through hydrolysis and condensation. In one embodiment of the present invention, the second curing temperature is 100~120℃, specifically 100℃, 105℃, 110℃, 115℃ or 120℃; the holding time is 60~120min, specifically 60min, 70min, 80min, 90min, 100min, 110min or 120min; under the above conditions, the second curing is beneficial to allow the acrylic resin to completely fill the gaps in the fiber cloth and promote the fusion of the acrylic resin-inorganic oxide phase interface. In one embodiment of the present invention, the third curing temperature is 140~170℃, specifically 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, or 170℃; the holding time is 30~60min, specifically 30min, 35min, 40min, 45min, 50min, 55min, or 60min; during the third curing process, the acrylic resin and the modified oxide sol are completely cured into a film; performing the third curing under the above conditions is beneficial to ensure that the modified oxide sol is completely cured to form a dense inorganic oxide phase and is simultaneously formed with the acrylic resin, ultimately obtaining an acrylic resin-based composite water-blocking film with excellent comprehensive performance. In one embodiment of the present invention, the heating rate during the thermosetting process is preferably ≤5℃ / min to avoid the formation of bubbles in the material due to a sudden temperature rise; the heating rate can further be 1~4℃ / min, and even more preferably 2~3℃ / min. In one embodiment of the present invention, after the thermosetting is completed, it is preferable to allow natural cooling to room temperature (25℃).

[0033] The present invention provides an acrylic resin-based composite water-blocking membrane prepared by the preparation method described above, comprising a fiber-reinforced acrylic resin composite membrane and inorganic oxides dispersed on the surface of the fiber-reinforced acrylic resin composite membrane; the fiber-reinforced acrylic resin composite membrane comprises an acrylic resin matrix and fibers dispersed in the acrylic resin matrix, wherein the inorganic oxides exist in the form of nanoparticles and a film.

[0034] In one embodiment of the present invention, the particle size of the nanoparticles is 5~50nm; the thickness of the acrylic resin-based composite water-blocking film is 100~500μm, specifically 100μm, 200μm, 300μm, 400μm or 500μm.

[0035] In the microstructure of the acrylic resin-based composite water-blocking membrane of this invention, reinforcing fibers are uniformly distributed in the acrylic resin matrix in the form of cross-linked long fiber bundles (fiber cloth). The inorganic oxide phase is dispersed in the form of nanoparticles (5~50nm) and micro-films on the surface of the fiber composite membrane, forming a "resin-fiber-resin-inorganic oxide" multi-layer composite structure with the acrylic resin matrix. However, macroscopically, it is a single-layer dense composite membrane with no obvious interfacial gaps or delamination. The surface is smooth with a surface roughness ≤0.8μm and free of visible cracks, bubbles, or inorganic oxide nanoparticle aggregates and other impurity particles (impurity particles with a particle size >1μm ≤3 / cm). 2 ).

[0036] The acrylic resin-based composite water-blocking film provided by this invention has excellent water-blocking performance, as well as high mechanical strength and light transmittance, which can meet the requirements of photovoltaic modules, especially flexible and lightweight photovoltaic modules, for "high water resistance + high mechanical strength + high light transmittance".

[0037] This invention provides the application of the acrylic resin-based composite water-blocking film described above in the encapsulation front plate, encapsulation back plate of photovoltaic modules, or conductive substrate for perovskite photovoltaic cells. This invention does not specifically limit the application; methods well known to those skilled in the art can be used.

[0038] Traditional photovoltaic water-blocking film production processes first prepare a fully cured polymer substrate, which suffers from surface defects. Specifically, the fully cured polymer substrate is prone to microcracks due to shrinkage during the curing process (especially fiber-reinforced substrates), and has poor surface smoothness (surface roughness is typically ≥2.5μm). Subsequent inorganic coating cannot fill these defects, leading to a decrease in water-blocking performance (water vapor transmission rate is generally ≥2g / m²). 2• 24h). Meanwhile, traditional photovoltaic water-blocking films also suffer from poor interfacial adhesion strength. Specifically, the polarity difference between the fully cured polymer substrate and the inorganic coating is significant, usually requiring additional surface treatment (such as plasma activation or coupling agent coating). However, the surface treatment effect is greatly affected by process parameters (such as plasma power and coupling agent concentration), resulting in high uncertainty and difficulty in forming stable chemical bonds. The interfacial adhesion strength is typically ≤3MPa, and delamination is prone to occur. Moreover, the traditional photovoltaic water-blocking film production process, "polymer substrate curing - surface treatment - coating curing," involves multiple steps, is complex, and has a long production cycle (typically ≥8h). Each step requires independent parameter control, resulting in low production efficiency and high cost. Based on the above problems, this invention proposes the concept of "simultaneous curing of acrylic prepreg coated with modified oxide sol". It utilizes the fluidity of the incompletely cured acrylic resin in the acrylic prepreg to match the dispersibility of the modified oxide sol. During the simultaneous curing process, while the acrylic resin cures to form the matrix skeleton, the modified oxide sol cures to form a film and forms chemical bonds (Si-OC bonds) with the acrylic resin. The interfacial adhesion strength is high, which avoids the surface defects of the fully cured polymer substrate and eliminates the need for additional surface treatment. It solves the three core problems of "surface defects, poor interfacial adhesion strength and complex process" in one step, and finally obtains a high-performance acrylic resin-based composite water-blocking film.

[0039] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] The amounts of raw materials used in the following experiments are based on the preparation of a water-blocking membrane per unit area; the specifications of the high-permeability glass fiber cloth used in the following experiments include: a basis weight of 100 g / m². 2 The transmittance is above 85% under light wavelength conditions of 380~1100nm; the high-transmittance glass fiber cloth was purchased from Shanghai Tianhuan Materials Technology Co., Ltd., model number 6126.

[0041] In the following experiments, room temperature refers to 25~30℃; the viscosity of the modified oxide sol refers to the viscosity at a temperature of 25℃.

[0042] Example 1 300g of acrylic resin powder (prepared according to the method in Example 1 of patent CN117701092A) was spread on the surface of high-transparency glass fiber cloth and placed in a laminator for lamination to allow some of the acrylic resin powder to undergo a cross-linking reaction to form a gel, thus obtaining an acrylic prepreg substrate. The lamination process included: evacuating the vacuum for 1 minute to a vacuum degree of 50 Pa, applying pressure for 1 minute to a pressure of 0.1 MPa, and then laminating at 160°C for 4 minutes. The degree of curing of the acrylic prepreg substrate was 20±2% (i.e., the mass of the acrylic resin powder that underwent the cross-linking reaction was 20±2% of the total mass of the acrylic resin powder), and the thickness of the acrylic prepreg substrate was 200 μm. At room temperature, 3.5 g of silane coupling agent (specifically KH-560) was mixed with 30 mL of ethanol-water solution (ethanol to deionized water volume ratio of 9:1), and the pH was adjusted to 3 with hydrochloric acid (concentration of 1 mol / L). Pre-hydrolysis was carried out at room temperature for 1 h to obtain a pre-hydrolyzed coupling agent. At room temperature, 104 g of tetraethyl orthosilicate (TEOS, purity ≥99%) was mixed with 100 mL of ethanol, and 60 mL of deionized water was added dropwise to the resulting system, followed by the addition of dilute hydrochloric acid (concentration of 1 mol / L). The pH value was adjusted to 2, and the resulting mixture was heated to 35°C and reacted for 2 hours under stirring to obtain a silica sol. The pre-hydrolysis coupling agent was added dropwise to the silica sol. After the addition of the pre-hydrolysis coupling agent was completed, the pH value was adjusted to 3 with dilute hydrochloric acid (concentration of 1.0 mol / L), and the temperature was raised to 60°C. The mixture was then subjected to modification treatment for 1.5 hours under stirring to obtain a modified oxide sol (specifically, a modified silica sol). The modified oxide sol had a solid content of 15 wt% and a viscosity of 80 mPa·s. The acrylic prepreg substrate is fixed on the coating machine platform, and the modified oxide sol is uniformly coated onto the surface of the acrylic prepreg substrate using a scraping method to obtain a prepreg-sol composite material. The conditions for the scraping method include: a scraper gap of 100 μm and a scraping speed of 1 m / min. The prepreg-sol composite material is then placed in a negative pressure environment (vacuum degree of -0.09 MPa) for 15 min to remove air bubbles, resulting in a degassed composite material. The degassed composite material is then placed in a laminator and pressurized to 0.1 MPa for thermosetting. The thermosetting includes: from room temperature to 3°C. The temperature is increased at 3°C / min to 40°C and held for a first curing of 30 min. Then, the temperature is increased at 3°C / min to 115°C and held for a second curing of 60 min. Then, the temperature is increased at 3°C / min to 150°C and held for a third curing of 60 min. After the third curing is completed, the temperature is naturally cooled to room temperature to obtain an acrylic resin-based composite water-blocking film (thickness of 300 μm; including a fiber-reinforced acrylic resin composite film and a silicon oxide barrier layer coated on its surface, wherein the silicon oxide barrier layer is formed by silicon oxide nanoparticles and a film, and the particle size of the silicon oxide nanoparticles is 5~50 nm).

[0043] Figure 1 The image shows an SEM image of the silica barrier layer in the acrylic resin-based composite water-blocking film in Example 1. The results show that after the modified silica sol and the prepreg are cured simultaneously, a dense surface structure without defects such as microcracks and pinholes can be formed, which is an ideal structure for the barrier coating.

[0044] Example 2 The procedure was performed according to the method in Example 1, except that the amount of tetraethyl orthosilicate was adjusted to 52g, the solid content of the resulting modified oxide sol was 7.5wt%, the viscosity was 60mPa·s, and the other operations were the same as in Example 1. Finally, an acrylic resin-based composite water-blocking membrane (thickness of 300μm) was prepared.

[0045] Example 3 The procedure was performed according to the method in Example 1, except that the first curing temperature was adjusted to 50°C, the second curing temperature was adjusted to 110°C, and the third curing temperature was adjusted to 140°C. Other operations were the same as in Example 1, and an acrylic resin-based composite water-blocking film (thickness of 300 μm) was finally prepared.

[0046] Example 4 The procedure is the same as in Example 1, except that the modified silica sol is replaced with modified alumina sol, and an acrylic resin-based composite water-blocking membrane (300 μm thick) is finally prepared. The preparation method of the modified alumina sol includes the following steps: At room temperature, 100g of aluminum isopropoxide (purity ≥99%) was mixed with 150mL of ethanol, and 60mL of deionized water was added dropwise to the resulting system. The mixture was heated to 35℃ and reacted for 2h under stirring. Then, 0.25g of aluminate coupling agent (specifically DL-411) was added dropwise to the resulting system. After the aluminate coupling agent was added, the mixture was stirred for 10min, and the pH was adjusted to 3 using hydrochloric acid (concentration 1.0mol / L). The temperature was raised to 60℃ and modified for 1.5h under stirring to obtain modified alumina sol. The modified alumina sol had a solid content of 10.7wt% and a viscosity of 35mPa·s.

[0047] Comparative Example 1 In this comparative example, an acrylic resin-based composite water-blocking membrane was prepared using the traditional "fully cured substrate + substrate surface treatment + post-coating" process, including the following steps: 300g of acrylic resin powder (same as in Example 1) was spread on the surface of high-transparency glass fiber cloth and placed in a laminator and pressurized to 0.1MPa for the first heat curing to obtain a fully cured substrate; the first heat curing included: heating from room temperature to 115°C and holding for 20min, then heating to 150°C and holding for 60min. The surface of the fully cured substrate was subjected to plasma treatment (in an argon atmosphere, at a power of 500W for 5 minutes) to obtain a surface-treated substrate; The surface-treated substrate was fixed on the coating machine stage, and silica sol (prepared by the same method as in Example 1) was uniformly coated onto the surface-treated substrate using a blade coating method to obtain a substrate-sol composite material. The conditions of the blade coating method included: a blade gap of 100 μm and a blade coating speed of 1 m / min. The substrate-sol composite material was placed in a negative pressure environment (vacuum degree of -0.09 MPa) for 15 min to remove air bubbles, resulting in a degassed composite material. The degassed composite material was placed in a laminator and pressurized to 0.1 MPa for a second thermosetting. The second thermosetting included: heating from room temperature to 40°C and holding at that temperature for 45 min, then heating to 80°C and holding at that temperature for 120 min. After the holding temperature was completed, the material was naturally cooled to room temperature to obtain an acrylic resin-based composite water-blocking film (thickness of 300 μm).

[0048] Comparative Example 2 The procedure was the same as in Comparative Example 1, except that the plasma treatment was replaced with a silane coupling agent modification treatment. Specifically, a 2% (w / w) aqueous solution of a silane coupling agent (specifically KH-560) was coated onto the surface of the fully cured substrate. Using the surface of the fully cured substrate as a reference, the coating amount of the silane coupling agent aqueous solution was 2 mL / 100 cm². 2After coating, the solvent was allowed to evaporate at room temperature for 15 minutes, and then heat-treated at 70°C for 30 minutes to obtain a surface-treated substrate. Then, an acrylic resin-based composite water-blocking film (thickness of 300 μm) was prepared using the surface-treated substrate according to the method of Comparative Example 1.

[0049] Test Example 1 The acrylic resin-based composite water-blocking membranes prepared in each embodiment and comparative example were subjected to performance tests. The water vapor transmission rate (WVTR) was tested according to GB / T 26253-2010; the tensile strength (TD or MD) was tested according to GB / T1040.3-2006, with a membrane thickness of 300 μm; the light transmittance was tested according to GB / T 2410-2008, with a wavelength of 550 nm; the interfacial adhesion strength (resin-oxide phase) was tested according to GB / T 529-2008; the surface roughness (Ra) was measured using an optical profilometer; and the aging resistance was specifically tested after being placed in an environment at 85℃ and 85% RH for 1000 hours. Specific results are shown in Table 1.

[0050] Table 1. Performance test results of acrylic resin-based composite water-blocking membranes in each embodiment and comparative example.

[0051] Compared with traditional photovoltaic water-blocking film production processes, this invention has at least the following beneficial effects: 1. Solving the interfacial bonding problem: In the acrylic prepreg of this invention, the curing of acrylic resin and the film-forming process of modified oxide sol are carried out simultaneously, which can effectively avoid the problems of interfacial delamination and insufficient bonding strength caused by the asynchronous curing of polymer substrate and inorganic coating in the traditional "first complete curing - then coating" process. The interfacial bonding strength of traditional photovoltaic water-blocking films is usually ≤3MPa, while the bonding strength of the acrylic resin-based composite water-blocking film prepared by this invention is ≥3.7MPa. In particular, when using modified silica sol, the bonding strength of the acrylic resin-based composite water-blocking film prepared is ≥8.2MPa (e.g., 8.2~9.5MPa).

[0052] 2. Improvement of surface defects: In the synchronous curing process of the present invention, the resin flowability of the acrylic prepreg and the dispersibility of the modified oxide sol are well matched. After coating with the modified oxide sol, the acrylic resin can fill the tiny voids in the modified oxide sol. At the same time, the modified oxide sol inhibits the cracks caused by the curing shrinkage of the acrylic resin, thereby avoiding surface unevenness, microcracks and other defects that are prone to occur in fully cured polymer substrates. For example, the surface roughness of traditional photovoltaic water-blocking films is ≥2.5μm and the microcrack incidence rate is >30%, while the surface roughness of the acrylic resin-based composite water-blocking film prepared by the present invention is ≤0.8μm (e.g., 0.5~0.8μm), and there are no visible or microscopic cracks.

[0053] 3. Improved water-blocking and mechanical properties: In the acrylic resin-based composite water-blocking membrane prepared by this invention, inorganic oxides form a nano-scale dense barrier phase (particle size 5~50nm) during simultaneous curing, forming a dense hybrid structure of "acrylic resin-inorganic oxide nanoparticles". This structure can extend the water vapor diffusion path and ensure that the water vapor transmission rate (WVTR) is ≤0.8g / m³. 2 • 24h (e.g., 0.3~0.8g / m) 2 • 24h, while traditional single resin membranes have a WVTR ≥ 2g / m 2 • 24h); while retaining the reinforcing properties of acrylic prepreg, and the inorganic oxide phase forms chemical bonds with the acrylic resin matrix (such as Si-OC bonds), which is conducive to further improving the interfacial bonding force and thus enhancing mechanical properties, ensuring tensile strength ≥140MPa (e.g., 141~163MPa; 300μm thickness), while traditional photovoltaic water-blocking films (such as commercial PET-based water-blocking films) have a tensile strength ≤120MPa due to interfacial defects.

[0054] 4. Simplified process and reduced uncertainty: The method of this invention eliminates the substrate surface treatment step (such as plasma activation and coupling agent coating) in the traditional photovoltaic water-blocking film production process, and completes the composite molding in one step. The production cycle is short, significantly shorter than the traditional photovoltaic water-blocking film production process cycle (usually ≥8h), and can effectively reduce the parameter fluctuations caused by surface treatment (such as the impact of treatment time and coupling agent concentration on the effect).

[0055] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an acrylic resin-based composite water barrier film, comprising the following steps: placing an acrylic resin material on a surface of a fiber cloth, and performing a lamination treatment to cause a partial cross-linking reaction of the acrylic resin material to form a gel, thereby obtaining an acrylic prepreg substrate; modifying an inorganic oxide sol with a coupling agent to obtain a modified oxide sol; and coating the modified oxide sol on a surface of the acrylic prepreg substrate, and sequentially performing defoaming and heat curing, thereby obtaining the acrylic resin-based composite water barrier film. The acrylic prepreg substrate has a curing degree of 10-22%. The lamination treatment comprises: vacuumizing for 50-70 s to a vacuum degree of 20-200 Pa, and then pressurizing for 50-70 s to a pressure of 0.1-0.3 MPa, and then laminating at a temperature of 155-165 ℃ for 3.5-4.5 min; and the acrylic prepreg substrate has a thickness of 100-350 μm. The inorganic oxide sol comprises a silica sol, an alumina sol or a titania sol; the precursor reagent used for preparing the inorganic oxide sol comprises tetraethyl orthosilicate, aluminum isopropoxide or tetrabutyl titanate; the modified oxide sol has a solid content of 7-20 wt% and a viscosity of 20-150 mPa·s.

2. The production method according to claim 1, characterized by, The acrylic resin material includes unmodified acrylic resin or modified acrylic resin, and the modified acrylic resin includes fluorosilicon modified acrylic resin, epoxy type acrylic resin or polyurethane modified acrylic resin; the fiber cloth includes glass fiber cloth, and the specification of the glass fiber cloth is 50-200 g / m 2 The light transmittance under the condition that the light wavelength is 380-1100 nm is ≥80%. The amount of the acrylic resin material is 50 to 600 g / m2 based on the area of the fiber cloth 2 ; The coating comprises blade coating, dip coating or spray coating.

3. The production method according to claim 1 or 2, characterized by, The blade coating has a viscosity of the modified oxide sol of 50-150 mPa·s, a blade gap of 50-300 μm and a blade coating speed of 0.5-2 m / min.

4. The production method according to claim 1, characterized by, The dip coating has a viscosity of the modified oxide sol of 40-60 mPa·s and a soaking time of 5-10 min.

5. The production method according to claim 1 or 4, characterized by, The spray coating has a viscosity of the modified oxide sol of 30-50 mPa·s and an atomization pressure of 0.3-0.5 MPa. The defoaming is vacuum defoaming, which has a vacuum degree of -0.09 to -0.08 MPa and a time of 10-20 min. The heat curing is performed at a pressure of 0.08-0.12 MPa, and comprises sequentially performing a first curing, a second curing and a third curing; the first curing has a temperature of 40-60 ℃ and a holding time of 30-60 min; the second curing has a temperature of 100-120 ℃ and a holding time of 60-120 min; and the third curing has a temperature of 140-170 ℃ and a holding time of 30-60 min. 8.An acrylic resin-based composite water barrier film prepared by the method of any one of claims 1-7, comprising a fiber-reinforced acrylic resin composite film and inorganic oxide dispersed on a surface of the fiber-reinforced acrylic resin composite film; the fiber-reinforced acrylic resin composite film comprises an acrylic resin matrix and fibers dispersed in the acrylic resin matrix, and the inorganic oxide exists in the form of nanoparticles and a film.

6. The method of claim 1, wherein, The nanoparticles have a particle size of 5-50 nm; and the acrylic resin-based composite water barrier film has a thickness of 100-500 μm.

7. The production method according to claim 1 or 6, characterized by, ​ ​ 9. The acrylic resin-based composite water barrier film according to claim 8, characterized by, ​ 10. Use of the acrylic resin-based composite water barrier film according to claim 8 or 9 in a front encapsulant sheet for a photovoltaic module, a back encapsulant sheet for a photovoltaic module, or an electrically conductive substrate for a perovskite photovoltaic cell.

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