Low-temperature cross-linked and high-oxygen-barrier perovskite packaging adhesive film and preparation method thereof

Abstract

The invention provides a low-temperature cross-linking and high-oxygen-barrier perovskite packaging adhesive film and a preparation method thereof. The adhesive film comprises polyethylene resin, liquid polybutadiene or semi-hydrogenated liquid polybutadiene or semi-hydrogenated C5 petroleum resin or semi-hydrogenated C9 petroleum resin, an organic peroxide cross-linking agent, an assistant cross-linking agent, an antioxidant, a silane coupling agent and the like. Wherein the polyethylene resin is ultra-low density polyethylene obtained by copolymerization of ethylene and alpha-olefin through a gas phase method, branching sites of the polyethylene prepared by the method are more than those of conventional LLDPE (Linear Low Density Polyethylene) and POE (Polyolefin Elastomer), the cross-linking performance is better, the molecular weight Mw is 50000-150000, the PDI is 1.5-3, the MFR measured under the conditions that the temperature is 190 DEG C and the load is 2.16 kg is 1-20g / 10min, and the density is 0.88-0.92 g / cm < 3 >. The oxygen barrier performance of the perovskite adhesive film is greatly improved, meanwhile, the low-temperature crosslinking performance is improved, the bulk resistance is high, and the weather resistance is good.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer films, and particularly to the technical field of encapsulation adhesive films dedicated to perovskites, belonging to the category of photovoltaic adhesive films. Background Art

[0002] As a third-generation new concept solar cell, perovskite solar cells have the advantages of high photoelectric conversion efficiency, low cost, and flexible processing. In recent years, they have developed rapidly. Their photoelectric conversion efficiency has increased from 3.8% at the beginning to 25.5% recently, gradually approaching that of silicon cells and being close to the commercial application level. In the process of moving towards practical applications, there are still major problems with the long-term stability of perovskite solar cells. In order to seek better future development and achieve industrialization as soon as possible, it is necessary to break through the stability bottleneck of perovskite solar cells. Improving the intrinsic stability and non-intrinsic stability of the battery are two main ways to achieve a longer service life of the battery. In terms of improving the intrinsic stability of solar cells, many research papers have proposed to improve it by methods such as doping, passivating, interfacial modification, and dimensional engineering of perovskite materials. However, improving only the intrinsic stability of perovskite cannot completely solve the current problem. At present, the key link in realizing the industrial application of perovskite solar cells lies in battery encapsulation, which can not only solve the stability problem of perovskite photovoltaic devices, but also meet the requirements of battery safety, environmental protection, and extended service life.

[0003] Traditional batteries usually use EVA or POE as encapsulation materials. However, perovskite batteries are sensitive to water and oxygen, and EVA with a high water permeability cannot be used. Only polyolefin resins with high water resistance can be selected, but conventional polyolefin resins have a high oxygen transmission rate. In addition to being sensitive to water and oxygen, perovskite batteries are unstable at high temperatures and require low-temperature encapsulation, which has high requirements for the low-temperature crosslinking performance, creep resistance, aging performance, oxygen barrier performance, and adhesion performance of the materials. Conventional polyolefin resins have a high crosslinking temperature and a slow speed, and there is no solution that meets all the above requirements so far. Summary of the Invention

[0004] Aiming at the current general situation of low-temperature crosslinking and oxygen barrier performance of perovskite adhesive films, the present invention provides a perovskite encapsulation adhesive film with low-temperature crosslinking and high oxygen barrier and its preparation method. The adhesive film includes ultra-low density polyethylene resin, liquid polybutadiene or semi-hydrogenated liquid polybutadiene or semi-hydrogenated C5 petroleum resin or semi-hydrogenated C9 petroleum resin, organic peroxide crosslinking agent, co-crosslinking agent, antioxidant, silane coupling agent, etc. First, liquid polybutadiene or semi-hydrogenated liquid polybutadiene or semi-hydrogenated C5 petroleum resin or semi-hydrogenated C9 petroleum resin is grafted onto the polyethylene resin in a certain proportion, and then mixed with various additives and cast to prepare the adhesive film. The present invention greatly improves the oxygen barrier performance of the perovskite adhesive film and at the same time improves the low-temperature crosslinking performance, with high volume resistance and good weather resistance. The technical solution adopted by the present invention is as follows:

[0005] A low-temperature crosslinking and high oxygen-barrier perovskite encapsulation film. This type of film includes polyethylene resin, liquid polybutadiene or semi-hydrogenated liquid polybutadiene or semi-hydrogenated C5 petroleum resin or semi-hydrogenated C9 petroleum resin, organic peroxide crosslinking agent, co-crosslinking agent, antioxidant, silane coupling agent, etc.

[0006] A low-temperature crosslinking and high oxygen-barrier perovskite encapsulation film, wherein the polyethylene resin is ultra-low density polyethylene copolymerized from ethylene and α-olefin by gas phase method. The polyethylene prepared by this method has more branching sites than conventional LLDPE and POE, better crosslinking performance, molecular weight Mw between 50,000 and 150,000, PDI of 1.5 - 3, and MFR measured under the conditions of 190 °C and 2.16 kg load is 1 - 20 g / 10 min, volume resistivity 10 15 -10 18 Ω·cm, density 0.88 - 0.92 g / cm 3 ; preferably MFR is 5 - 15 g / 10 min, volume resistivity 10 17 -10 18 Ω·cm, density 0.88 - 0.90 g / cm 3 。

[0007] A low-temperature crosslinking and high oxygen-barrier perovskite encapsulation film. In the presence of a graft initiator, liquid polybutadiene or semi-hydrogenated liquid polybutadiene or semi-hydrogenated C5 petroleum resin or semi-hydrogenated C9 petroleum resin is grafted onto the polyethylene resin to obtain a graft resin; the addition amounts of each substance are in parts by mass: 100 parts of polyethylene resin; 1 - 20 parts of liquid polybutadiene or semi-hydrogenated liquid polybutadiene or semi-hydrogenated C5 petroleum resin or semi-hydrogenated C9 petroleum resin; 0.1 - 1 part of initiator.

[0008] Furthermore, the crosslinking agent in the low-temperature crosslinking and high oxygen-barrier perovskite encapsulation film is a peroxide crosslinking agent, including but not limited to one or more of the following: 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl peroxycarbonate-2-ethylhexyl, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-(bis-tert-butylperoxy)hexane, 1,1-bis(tert-amylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amyl peroxy-2-ethylhexyl carbonate, tert-amyl peroxycarbonate, tert-butyl peroxy-3,3,5-trimethylhexanoate, tert-butyl peroxycarbonate isopropyl, tert-butyl peroxy-2-ethylhexyl carbonate. Based on 100 parts by weight of the graft resin, the amount of the organic peroxide crosslinking agent is 0.1 - 5 parts by weight. Preferably 0.5 - 2 parts by weight.

[0009] Further, the co-crosslinking agent is one or more of polyfunctional acrylate substances, including but not limited to one or several of the following: trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, trimethylolpropane tetraacrylate, ditrimethylolpropane tetraacrylate, ditrimethylolpropane tetramethacrylate, propoxylated pentaerythritol tetraacrylate, tricyclodecane dimethanol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate. Based on 100 parts by weight of the graft resin, the amount of the co-crosslinking agent is 0.1-5 parts by weight, preferably 0.1-2 parts by weight.

[0010] Further, the coupling agent is a silane coupling agent, including but not limited to one or several of the following: γ-chloropropylmethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, 3-(trimethoxysilyl)propyl-2-methyl-2-acrylate, anilinomethyltriethoxysilane, octyltrimethoxysilane. Based on 100 parts by weight of the graft resin, the amount of the coupling agent is 0.1-3 parts by weight, preferably 0.1-0.6 parts by weight.

[0011] Further, the antioxidant is one or more of hindered phenol antioxidants or phosphate antioxidants, including but not limited to one or more of the following: n-octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], bis(3,5-di-tert-butyl-4-hydroxypropionyl) hydrazine, 2,2'-oxamido-bis [ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, triethylene glycol bis [3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 4,6-bis(octylthiomethyl) o-cresol, tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite. Based on 100 parts by weight of the grafted resin, the amount of the antioxidant is 0.01-1 part by weight, preferably 0.05-0.5 part by weight.

[0012] The preparation of the low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film further includes the following steps: premixing the grafted resin with various additives, standing, melt-extruding, casting into a film, cooling and slitting, and winding, to prepare the film with both high water resistance and oxygen barrier properties, good low-temperature cross-linking performance, high light transmittance, and excellent aging performance.

[0013] The beneficial effects of the low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film and its preparation method of the present invention are as follows: based on the polyethylene with high branching sites as the base resin, good cross-linking performance is provided; a part of the double bonds in the grafted liquid polybutadiene or semi-hydrogenated liquid polybutadiene or semi-hydrogenated C5 petroleum resin or semi-hydrogenated C9 petroleum resin can improve the low-temperature cross-linking performance, and the remaining part can be present in the film to continuously absorb trace oxygen during long-term use, improving the oxygen barrier property of the film, so as to simultaneously have the characteristics of high water resistance and high oxygen barrier. Specific Embodiments

[0014] The following further illustrates the present invention through specific examples. The examples described in the present invention are only for the illustration of the present invention and do not limit the scope of the present invention.

[0015] The following examples are used to illustrate the present invention, but are not used to limit the scope of the present invention. In this application, "parts" and "%" are by weight, unless otherwise specified.

[0016] Examples and Comparative Examples

[0017] Example 1:

[0018] A preparation method of a low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film is carried out according to the following steps: Polyethylene resin with a molecular weight Mw of 80,000, PDI of 2.1, MFR of 5 g / 10 min measured under the conditions of 190 °C and 2.16 kg load, volume resistivity of 3×10 17 Ω·cm, and density of 0.885 g / cm 3 , liquid 1,2-polybutadiene with a molecular weight of 2000, and a graft initiator are mixed in a mixer for 120 min until uniform; then put into a twin-screw extruder for grafting reaction and granulated to obtain grafted polyethylene-1.

[0019] An organic peroxide cross-linking agent, a co-cross-linking agent, an antioxidant, and a silane coupling agent are sheared by a high-speed disperser for 30 min to reduce the viscosity of the mixed additives to 1 - 300 mPa·s; the mixed additives are added to the grafted polyethylene-1 after grafting, and mixed at high speed for 6 - 12 h until the additives are completely absorbed.

[0020] The mixed ingredients are added into a casting machine through a feeding system, cast and extruded at 80 - 120 °C, the film is drawn into an embossing roller for pressing to form patterns, cooled and shaped, then slit and wound, and packaged into finished products as required.

[0021] Example 2

[0022] A preparation method of a low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film is carried out according to the following steps: Polyethylene resin with a molecular weight Mw of 150,000, PDI of 1.5, MFR of 1 g / 10 min measured under the conditions of 190 °C and 2.16 kg load, volume resistivity of 1×10 18 Ω·cm, and density of 0.920 g / cm 3 , liquid 1,2-polybutadiene with a molecular weight of 3000, and a graft initiator are mixed in a mixer for 120 min until uniform; then put into a twin-screw extruder for grafting reaction and granulated to obtain grafted polyethylene-2.

[0023] An organic peroxide cross-linking agent, a co-cross-linking agent, an antioxidant, and a silane coupling agent are sheared by a high-speed disperser for 30 min to reduce the viscosity of the mixed additives to 1 - 300 mPa·s; the mixed additives are added to the grafted polyethylene-2 after grafting, and mixed at high speed for 6 - 12 h until the additives are completely absorbed.

[0024] The mixed ingredients are added into a casting machine through a feeding system, cast and extruded at 80 - 120 °C, the film is drawn into an embossing roller for pressing to form patterns, cooled and shaped, then slit and wound, and packaged into finished products as required.

[0025] Example 3

[0026] A preparation method of a low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film is carried out according to the following steps: Polyethylene resin with a molecular weight Mw of 110,000, a PDI of 3, an MFR of 3 g / 10 min measured under the conditions of 190 °C and a load of 2.16 kg, a volume resistivity of 6×10 17 Ω·cm, and a density of 0.880 g / cm 3 , semi-hydrogenated liquid 1,4-polybutadiene with a molecular weight of 1000, and a grafting initiator are mixed in a mixer for 120 min until uniform; then put into a twin-screw extruder for grafting reaction and granulated to obtain grafted polyethylene-3.

[0027] An organic peroxide cross-linking agent, a co-cross-linking agent, an antioxidant, and a silane coupling agent are sheared by a high-speed disperser for 30 min to reduce the viscosity of the mixed auxiliary agents to 1 - 300 mPa·s; the mixed auxiliary agents are added to the grafted polyethylene-3 after grafting, and mixed at high speed for 6 - 12 h until the auxiliary agents are completely absorbed.

[0028] The mixed ingredients are added into a casting machine through a feeding system, cast and extruded at 80 - 120 °C, the film is drawn into an embossing roller for pressing to form patterns, cooled and shaped, then slit and wound, and packaged into finished products as required.

[0029] Example 4

[0030] A preparation method of a low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film is carried out according to the following steps: Polyethylene resin with a molecular weight Mw of 50,000, a PDI of 1.5, an MFR of 20 g / 10 min measured under the conditions of 190 °C and a load of 2.16 kg, a volume resistivity of 1×10 17 Ω·cm, and a density of 0.905 g / cm 3 , semi-hydrogenated C5 petroleum resin with a molecular weight of 3000, and a grafting initiator are mixed in a mixer for 120 min until uniform; then put into a twin-screw extruder for grafting reaction and granulated to obtain grafted polyethylene-4.

[0031] An organic peroxide cross-linking agent, a co-cross-linking agent, an antioxidant, and a silane coupling agent are sheared by a high-speed disperser for 30 min to reduce the viscosity of the mixed auxiliary agents to 1 - 300 mPa·s; the mixed auxiliary agents are added to the grafted polyethylene-4 after grafting, and mixed at high speed for 6 - 12 h until the auxiliary agents are completely absorbed.

[0032] The mixed ingredients are added into a casting machine through a feeding system, cast and extruded at 80 - 120 °C, the film is drawn into an embossing roller for pressing to form patterns, cooled and shaped, then slit and wound, and packaged into finished products as required.

[0033] Comparative Example 1

[0034] The POE resin with a molecular weight Mw of 50,000, a PDI of 2.3, an MFR of 15 g / 10 min measured under the conditions of 190 °C and a load of 2.16 kg, a volume resistivity of 6×10 16 Ω·cm, and a density of 0.873 g / cm 3 is mixed with an organic peroxide crosslinking agent, a co-crosslinking agent, an antioxidant, and a silane coupling agent for 6 - 12 h until the additives are completely absorbed.

[0035] The mixed ingredients are added into a casting machine through a feeding system, cast and extruded at 80 - 120 °C, the film is drawn into an embossing roller for pressing to form patterns, and after cooling and shaping, it is slit and wound, and packaged into finished products as required.

[0036] Comparative Example 2

[0037] The POE resin with a molecular weight Mw of 70,000, a PDI of 2.5, an MFR of 5 g / 10 min measured under the conditions of 190 °C and a load of 2.16 kg, a volume resistivity of 2×10 16 Ω·cm, and a density of 0.874 g / cm 3 and the LLDPE resin with a melt index of 10 g / 10 min and a melting point of 105 °C, and a grafting initiator are mixed in a mixer for 120 min until uniform; then put into a twin-screw extruder for grafting reaction and granulated to obtain grafted POE.

[0038] The organic peroxide crosslinking agent, co-crosslinking agent, antioxidant, and silane coupling agent are sheared by a high-speed disperser for 30 min to reduce the viscosity of the mixed additives to 1 - 300 mPa·s; the mixed additives are added to the grafted POE after grafting and mixed at high speed for 6 - 12 h until the additives are completely absorbed.

[0039] The mixed ingredients are added into a casting machine through a feeding system, cast and extruded at 80 - 120 °C, the film is drawn into an embossing roller for pressing to form patterns, and after cooling and shaping, it is slit and wound, and packaged into finished products as required.

[0040] Test results of examples and comparative examples:

[0041]

[0042] It can be seen from the comparison of the performance test data of the above examples and comparative examples that:

[0043] A perovskite encapsulation film with low-temperature crosslinking and high oxygen barrier provided by the present invention has achieved the following performance improvements:

[0044] 1. Using ultra-low density polyethylene with high branching sites as the base resin, the vulcanization speed is faster than that of POE, and it is more suitable for the low-temperature crosslinking scenario of perovskite;

[0045] 2. Graft components containing a certain amount of double bonds, such as liquid polybutadiene, onto polyethylene. Some of the double bonds can promote the cross-linking reaction and improve the low-temperature cross-linking degree; the remaining double bonds can slowly absorb oxygen molecules during the long-term use of the film, playing an oxygen barrier role.

[0046] 3. The main components used in the present invention are all polyolefin resins, which have high water resistance, good light transmittance, and good weather resistance. After grafting liquid polybutadiene, etc., the adhesion performance is improved, and the peel strength is greatly increased, making it suitable for use as a perovskite solar cell film.

[0047] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the method of the present invention, several improvements and supplements can be made, and these improvements and supplements should also be regarded as the protection scope of the present invention.

Claims

1. A low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film, characterized in that: The adhesive film comprises a polyethylene resin, liquid polybutadiene or semi-hydrogenated liquid polybutadiene or semi-hydrogenated C5 petroleum resin or semi-hydrogenated C9 petroleum resin, an organic peroxide crosslinking agent, a co-crosslinking agent, an antioxidant, a silane coupling agent, etc.

2. The low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film according to claim 1, characterized in that: The polyethylene resin is an ultra-low density polyethylene copolymerized from ethylene and α-olefin by gas phase method, with a molecular weight Mw between 50,000 and 150,000, a PDI of 1.5 - 3, and an MFR of 1 - 20 g / 10 min measured under the conditions of 190 °C and a load of 2.16 kg, and a volume resistivity of 10 15 -10 18 Ω·cm, and a density of 0.88 - 0.92 g / cm 3 ; preferably, the MFR is 5 - 15 g / 10 min, the volume resistivity is 10 17 -10 18 Ω·cm, and the density is 0.88 - 0.90 g / cm 3 .

3. The low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film according to claim 1, characterized in that: In the presence of a graft initiator, liquid polybutadiene or semi-hydrogenated liquid polybutadiene or semi-hydrogenated C5 petroleum resin or semi-hydrogenated C9 petroleum resin is grafted onto the polyethylene resin to obtain a graft resin; the addition amounts of each substance are respectively in parts by mass: 100 parts of polyethylene resin; 1-20 parts of liquid polybutadiene or semi-hydrogenated liquid polybutadiene or semi-hydrogenated C5 petroleum resin or semi-hydrogenated C9 petroleum resin; 0.1-1 part of initiator.

4. The low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film according to claim 1, characterized in that: The antioxidant is one or more of an ultraviolet absorber and a heat aging decomposition inhibitor, preferably including one or more of antioxidant 1010, antioxidant 770 and antioxidant 1076; the silane coupling agent is an organosilicon compound containing two different chemically reactive groups in the molecule, preferably including one or more of silane coupling agent A-171 and silane coupling agent A-174; the organic peroxide crosslinking agent includes one or more of dicumyl peroxide, tert-butyl peroxy-2-ethylhexyl carbonate and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; the co-crosslinking agent includes one or more of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane triacrylate and trimethylolpropane trimethacrylate.

5. The low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film according to claim 3 or 4, characterized in that: It is made from the following formula components:

6. The preparation method of the low-temperature cross-linking and high-oxygen-barrier perovskite encapsulation film according to claim 1, characterized in that: It includes the following steps: Raw material premixing, standing, melt extrusion, casting film formation, cooling and slitting, and winding processes to prepare the encapsulation adhesive film with more excellent oxygen barrier performance and low-temperature crosslinking performance, high volume resistivity, and good weather resistance.

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