Multi-layer packaging adhesive film and preparation method thereof

Abstract

The invention relates to a multilayer packaging adhesive film and a preparation method thereof. The multilayer packaging adhesive film is composed of a middle layer, an upper surface layer and a lower surface layer, wherein the upper surface layer and the lower surface layer are located on two sides of the middle layer. The middle layer is subjected to molecular structure and formula design, the unsaturated functional ethylene-alpha olefin copolymer can increase the polarity of the middle layer and reduce precipitation of auxiliaries to the upper surface layer and the lower surface layer, meanwhile, the unsaturated functional ethylene-alpha olefin copolymer and a monomer containing a polythiol group are subjected to a sulfydryl-double bond addition reaction under ultraviolet irradiation, a certain degree of pre-crosslinking occurs, and precipitation of auxiliaries in the middle layer is reduced. The multilayer packaging adhesive film prepared by the invention has the characteristics of fast crosslinking, high crosslinking degree, high bonding strength and the like, and can be used in the field of packaging battery materials.

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaic applications, and particularly relates to a multi-layer encapsulation film with excellent cross-linking performance and a preparation method thereof. Background Art

[0002] With the continuous breakthrough of new technologies in the photovoltaic industry, the power generation efficiency of batteries has been gradually improved, and it has gradually developed from Perc batteries to N-type batteries. The development of batteries has also put forward new requirements for encapsulation materials, and the requirements for performance such as adhesion performance, anti-PID performance, water barrier performance, and corrosion resistance are getting higher and higher; at the same time, cost reduction is also an eternal topic in the photovoltaic industry. How to continuously reduce the material cost on the premise of ensuring that the encapsulation materials meet the usage requirements is the goal pursued by each photovoltaic enterprise.

[0003] Currently, most of the films used in the encapsulation material industry are cross-linked films. A cross-linking agent, a cross-linking aid, and other additives are mixed into the matrix resin, and the film is formed by extrusion casting. For example, Patent CN111117498B discloses a photovoltaic photo-thermal dual-curing POE encapsulation film and a preparation method thereof. The encapsulation film includes the following components: POE polyolefin elastomer, free radical thermal initiator, photoinitiator, acrylamide-based cross-linking aid, acrylate-based cross-linking aid, light stabilizer, antioxidant, macromolecular coupling agent, tackifying resin. The use of initiators and cross-linking aids improves the cross-linking degree. However, there are generally problems such as a large amount of additives used, easy precipitation of additives, and high costs. At the same time, as the N-type battery industry technology gradually matures, the encapsulation materials in the industry are gradually changing from POE / EVA films to EPE three-layer structures. For example, Patent CN107502209B discloses a three-layer structure solar cell encapsulation film and a preparation method thereof. Through the formulation design of the core layer and the skin layer, the purpose of a certain degree of pre-cross-linking is achieved. However, from the results, there are still problems such as unstable peel strength and low cross-linking degree. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a multi-layer encapsulation film with excellent cross-linking performance and a preparation method thereof. The encapsulation film solves the problems of uneven thickness and low cross-linking degree in the multi-layer co-extrusion technology through two composite cross-linking methods under the condition of using a lower amount of additives.

[0005] The object of the present invention is achieved by the following technical solutions:

[0006] A multi-layer encapsulation film, comprising an intermediate layer and upper and lower surface layers located on both sides of the intermediate layer;

[0007] The intermediate layer includes the following components in parts by mass:

[0008]

[0009] The upper surface layer and the lower surface layer independently include the following components in parts by mass:

[0010]

[0011] Further, the preparation method of the unsaturated functional ethylene-α-olefin copolymer includes the following steps: Mix an ethylene-α-olefin copolymer, an initiator, and functional auxiliary B in a mass ratio of 100:0.01-5:0.5-10, conduct melt grafting, and granulate through a twin-screw extruder to obtain the unsaturated functional ethylene-α-olefin copolymer.

[0012] As a preferred embodiment, the preparation method of the unsaturated functional ethylene-α-olefin copolymer includes the following steps: Mix an ethylene-α-olefin copolymer, an initiator, and functional auxiliary B in a mass ratio of 100:0.01-5:0.5-10, conduct melt grafting, with a processing temperature of 120-190 °C and a screw rotation speed of 50-80 r / min for a 50 mm diameter screw, and granulate through a twin-screw extruder to obtain the unsaturated functional ethylene-α-olefin copolymer.

[0013] Further, the ethylene-α-olefin copolymer is one or more of an ethylene-propylene copolymer, an ethylene-1-butene copolymer, an ethylene-1-hexene copolymer, an ethylene-1-octene copolymer, and an ethylene-1-decene copolymer; its melt index is 1-30 g / 10 min, the number average molecular weight is 30000-150000 g / mol, the α-olefin mass insertion rate is 5-50 wt%, and the melting peak temperature is 35-120 °C.

[0014] Further, the functional auxiliary A is a polythiol monomer containing at least two mercapto groups, and its molecular weight is 60-1000 g / mol.

[0015] Further, the functional auxiliary A includes, but is not limited to, one or more of 1,2-ethanedithiol, 1,2-propanedithiol, 1,2-butanedithiol, 2,3-dithio(2-mercapto)-1-propanethiol, bis(3-mercaptopropionic acid) ethylene ester, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetra(3-mercaptopropionate), and dipentaerythritol hexa(3-mercaptopropionate).

[0016] Further, the functional auxiliary B is an acrylate monomer containing at least two double bonds, and its molecular weight is 100-2000 g / mol.

[0017] Further, the functional additive B includes, but is not limited to, one or more of 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, diethylene glycol dimethacrylate, and triethylene glycol dimethacrylate.

[0018] Further, the initiator includes, but is not limited to, peroxide initiators, preferably one or more of dicumyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, di-tert-butyl peroxide, and tert-butyl peroxy-2-ethylhexyl carbonate.

[0019] Further, the vinyl copolymer includes, but is not limited to, one or more of ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, and ethylene-1-decene copolymer, with a melt index of 1-40 g / 10 min and a comonomer mass insertion rate of 5-60 wt%.

[0020] Further, the crosslinking agent includes, but is not limited to, one or more of isopropyl t-butyl peroxycarbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl peroxy-2-ethylhexyl carbonate, tert-amyl peroxy-2-ethylhexyl carbonate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amyl peroxycarbonate, and tert-butyl peroxy-3,3,5-trimethylhexanoate.

[0021] Further, the crosslinking aid includes, but is not limited to, one or more of triallyl cyanurate, triisocyanuric acid triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane trimethacrylate, triethylene glycol dimethacrylate, dipropylene glycol diacrylate, diethylene glycol dimethacrylate, and ethylene glycol dimethacrylate.

[0022] Further, the tackifier includes, but is not limited to, one or more of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(β - methoxyethoxy)silane, 3 - (methacryloyloxy)propyltrimethoxysilane, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, and aminopropyltriisopropoxysilane.

[0023] Further, the antioxidant includes, but is not limited to, one or more of tris(2,4 - di - tert - butylphenyl) phosphite, octadecyl 3 - (3,5 - di - tert - butyl - 4 - hydroxyphenyl) propionate, distearyl pentaerythritol diphosphite, tris(nonylphenyl) phosphite, 2,2'-methylenebis(4 - methyl - 6 - tert - butylphenol), triethylene glycol bis(3 - tert - butyl - 4 - hydroxy - 5 - methylphenyl) propionate, 1,3,5 - trimethyl - 2,4,6 - tris(3,5 - di - tert - butyl - 4 - hydroxybenzyl) benzene, tris(2,4 - di - tert - butylphenyl) phosphite, bis(2,4 - di - tert - butylphenyl)pentaerythritol diphosphite, and bis(2,6 - di - tert - butyl - 4 - methylphenyl)pentaerythritol diphosphite.

[0024] Further, the light stabilizer includes, but is not limited to, one or more of bis(2,2,6,6 - tetramethyl - 4 - piperidyl) sebacate, mono(2,2,6,6 - tetramethyl - 4 - piperidyl) sebacate, bis(1,2,2,6,6 - pentamethyl - 4 - piperidyl) sebacate, and poly[succinic acid, 1,2 - ethanediylbis[(2,2,6,6 - tetramethyl - 4 - piperidinyl) oxy]] ester.

[0025] The present invention provides a method for preparing the multi-layer encapsulation adhesive film, comprising the following steps: fully mixing the upper surface layer, lower surface layer and intermediate layer formulation materials respectively, melting and extruding them through three single-screw extruders, the extrusion temperature being 70-90 °C, the screw rotation speed of 25-40 mm diameter being 5-15 r / min, forming a three-layer film by casting through a die head distributor according to the upper surface layer / intermediate layer / lower surface layer via a traction roller, the thickness of the adhesive film surface layer being 0.05-0.15 mm, the thickness of the intermediate layer being 0.1-0.4 mm, and irradiating with UV ultraviolet light during the casting and winding process, the irradiation dose being 5-10 J / cm 2 , and the continuous irradiation time being 50-100 s.

[0026] The crosslinking degree of the unlaminated adhesive film of the present invention is between 5-20%, the T90 measured under the lamination conditions of 145 °C and 15 min is less than 11 min, the crosslinking degree is greater than 80%, and the initial peel strength from glass is greater than 200 N / cm.

[0027] The beneficial effects of the present invention are as follows: The multi-layer encapsulation adhesive film with excellent crosslinking performance obtained by the present invention designs the molecular structure and formulation of the intermediate layer. The unsaturated functional ethylene-α-olefin copolymer can increase the polarity of the intermediate layer, reduce the precipitation of additives to the upper and lower surface layers, and at the same time, through the thiol-double bond addition reaction with the monomer containing a polythiol group under ultraviolet light irradiation, a certain degree of pre-crosslinking occurs. While locking the additives, the fluidity of the intermediate layer during lamination is reduced, ensuring the thickness stability of the three-layer structure of the adhesive film. The unreacted monomer containing a polythiol group continues to react with other additives during lamination, increasing the crosslinking performance of the intermediate layer. Specific Embodiments

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] Example 1

[0030] Surface layer ingredients:

[0031] Vinyl copolymer: ethylene-vinyl acetate copolymer (Sirbon V2825)

[0032] Crosslinking agent: 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane

[0033] Co-crosslinking agent: ethoxylated trimethylolpropane triacrylate

[0034] Antioxidant: n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

[0035] Light stabilizer: bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate

[0036] Tackifier: methacryloxypropyltrimethoxysilane

[0037] Intermediate layer formulation:

[0038] Unsaturated functional ethylene-α-olefin copolymer: 100 parts by mass of ethylene-1-octene copolymer (Dow 8660), 0.25 parts by mass of dicumyl peroxide DCP, and 3.0 parts by mass of trimethylolpropane triacrylate were mixed evenly and granulated by a twin-screw extruder to obtain an unsaturated functional ethylene-α-olefin copolymer.

[0039] Ethylene-α-olefin copolymer: ethylene-1-octene copolymer (Dow 8660)

[0040] Functional additive A: 1,2-propanedithiol

[0041] Crosslinking agent: tert-amyl peroxy-2-ethylhexyl carbonate

[0042] Co-crosslinking agent: triallyl cyanurate

[0043] Antioxidant: n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate

[0044] Light stabilizer: bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate

[0045] The upper and lower surface layer and intermediate layer formulation materials were respectively mixed thoroughly, and melt-extruded through three single-screw extruders. The extrusion temperature was 70-90 °C, the screw speed of the 35 mm diameter screw was 5-15 r / min, and the three-layer film was cast by a die distributor according to the upper surface layer / intermediate layer / lower surface layer through a take-up roller. The thickness of the surface layer of the adhesive film was 0.05-0.15 mm, and the thickness of the intermediate layer was 0.1-0.4 mm. During the casting and winding process, it was irradiated with UV ultraviolet light, the irradiation dose was 5-10 J / cm 2 , continuously irradiated for 60 s, and finally wound into a film, denoted as H1.

[0046] Example 2

[0047] In the intermediate layer formulation, functional additive B was selected as triethylene glycol dimethacrylate, and the remaining steps were the same as in Example 1 to obtain an unsaturated functional ethylene-α-olefin copolymer.

[0048] In the intermediate layer formulation, functional additive A was selected as bis(3-mercaptopropionic acid) ethylene ester, and the remaining steps were the same as in Example 1 to obtain an encapsulation adhesive film denoted as H2.

[0049] Example 3

[0050] In the surface layer formulation, the vinyl copolymer is selected as ethylene-1-butene copolymer (LG575).

[0051] In the intermediate layer formulation, the functional additive B is selected as pentaerythritol tetraacrylate, and the remaining steps are the same as in Example 1 to obtain an unsaturated functional ethylene-α-olefin copolymer.

[0052] In the intermediate layer formulation, the functional additive A is selected as dipentaerythritol hexakis(3-mercaptopropionate), and the remaining steps are the same as in Example 1 to obtain an encapsulation film denoted as H3.

[0053] Example 4

[0054] In the intermediate layer formulation, the functional additive B is selected as ethoxylated trimethylolpropane trimethacrylate, and the remaining steps are the same as in Example 1 to obtain an unsaturated functional ethylene-α-olefin copolymer.

[0055] In the intermediate layer formulation, the functional additive A is selected as trimethylolpropane tris(3-mercaptopropionate), and the remaining steps are the same as in Example 1 to obtain an encapsulation film denoted as H4.

[0056] Example 5

[0057] In the surface layer formulation, the vinyl copolymer is selected as ethylene-1-butene copolymer (LG675).

[0058] In the intermediate layer formulation, the functional additive B is selected as dipropylene glycol diacrylate, and the remaining steps are the same as in Example 1 to obtain an unsaturated functional ethylene-α-olefin copolymer.

[0059] In the intermediate layer formulation, the functional additive A is selected as pentaerythritol tetrakis(3-mercaptopropionate), and the remaining steps are the same as in Example 1 to obtain an encapsulation film denoted as H5.

[0060] Comparative Examples

[0061] To better demonstrate the beneficial effects of the present invention, three comparative examples are listed, denoted as W1-3. In W1, the addition amount of the unsaturated functional ethylene-α-olefin copolymer in the intermediate layer is 0, and the addition amount of the ethylene-1-octene copolymer is 100, and the rest is the same as in Example 1; in W2, the addition amount of the functional additive A in the intermediate layer is 0, and the rest is the same as in Example 2; in W3, the addition amounts of the unsaturated functional ethylene-α-olefin copolymer and the functional additive A in the intermediate layer are reduced. The formulations of Examples 1-5 and the comparative examples are listed in Table 1.

[0062] Table 1 Formulations of Examples and Comparative Examples

[0063]

[0064]

[0065] Performance Test

[0066] The encapsulation adhesive films obtained through the above-mentioned examples and comparative examples were applied to the encapsulation of solar cell modules and evaluated by the following test methods. The evaluation results are listed in Table 2.

[0067] 1. Crosslinking degree

[0068] The test method refers to the China Photovoltaic Industry Association standard T / CPIA 0006—2017 "Copolyolefin Films for Photovoltaic Module Encapsulation".

[0069] Sample preparation: After taking two adhesive films and laminating them together, laminate them in a laminator (laminating conditions: 145 °C, vacuum pumping for 6 min, laminating for 10 min), then weigh 0.5 g ± 0.01 g, and cut them into small pieces of adhesive film with dimensions less than 3 mm × 3 mm. Prepare 3 specimens for each group.

[0070] Extract with xylene at 140 °C for 5 h, then put it into a vacuum oven at 140 °C and dry to constant weight.

[0071] 2. Initial crosslinking degree

[0072] After taking two adhesive films and laminating them together, weigh 0.5 g ± 0.01 g, and cut them into small pieces of adhesive film with dimensions less than 3 mm × 3 mm. Prepare 3 specimens for each group.

[0073] Extract with xylene at 140 °C for 5 h, then put it into a vacuum oven at 140 °C and dry to constant weight.

[0074] 3. Glass / encapsulation adhesive film bonding strength

[0075] The test method refers to the national standard GB / T2790 "Test Method for 180° Peel Strength of Adhesives - Flexible Materials to Rigid Materials".

[0076] Sample preparation: Take 3.2 mm thick ultra-white embossed tempered glass, double-layer encapsulation adhesive film, and TPT backsheet, and place them in a vacuum laminator in the order of glass / adhesive film / backsheet, and laminate and cure at 150 °C for 18 min.

[0077] Conduct tests on a tensile machine at a tensile speed of 100 mm / min and record the tensile strength value.

[0078] 4. Optimal vulcanization time T90

[0079] Measure the optimal vulcanization time T90 of the adhesive film according to GB / T 16584-1996. T90 is used to characterize the crosslinking speed. The smaller the T90 time, the faster the crosslinking speed.

[0080] 5. Intermediate layer thickness difference d

[0081] Take a piece of adhesive film, laminate it with a laminator, and cut it into small pieces of adhesive film with a size of 10 mm × 20 mm. Place it in a metallurgical microscope to observe the thickness of the intermediate layer. The thickness difference d of the intermediate layer = maximum value - minimum value.

[0082] The performance comparison of the encapsulation adhesive films prepared in the examples and comparative examples is shown in Table 2:

[0083] Table 2 Performance comparison of the encapsulation adhesive films prepared in the examples and comparative examples From the performance data of the above examples and comparative examples, it can be seen that the multi-layer encapsulation adhesive film with excellent cross-linking performance of the present invention has an obviously short vulcanization time, excellent bonding strength and intermediate layer thickness stability.

Claims

1. A multi-layer packaging film, comprising an intermediate layer and an upper surface layer and a lower surface layer located on both sides of the intermediate layer; The intermediate layer comprises the following components by weight: The upper surface layer and the lower surface layer independently include the following components by weight:

2. The multi-layer packaging film according to claim 1, characterized in that: The preparation method of the unsaturated functional ethylene-alpha olefin copolymer comprises the following steps: mixing the ethylene-alpha olefin copolymer, an initiator and a functional auxiliary agent B in a mass ratio of 100:0.01-5:0.5-10, performing melt grafting, and granulating through a twin-screw extruder to obtain the unsaturated functional ethylene-alpha olefin copolymer.

3. The multi-layer packaging film according to claim 1 or 2, characterized in that: The ethylene-α-olefin copolymer is one or more of ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, and ethylene-1-decene copolymer; its melt index is 1-30 g / 10 min, the number average molecular weight is 30000-150000 g / mol, the α-olefin mass insertion rate is 5-50 wt%, and the melting peak temperature is 35-120° C.

4. The multi-layer packaging film according to any one of claims 1 to 3, characterized in that: The functional auxiliary agent A is a polythiol monomer containing at least two mercapto groups, and its molecular weight is 60-1000 g / mol; preferably, the functional auxiliary agent A includes one or more of 1,2-ethanedithiol, 1,2-propylenethiol, 1,2-butanethiol, 2,3-dithio(2-mercapto)-1-propanethiol, bis(3-mercaptopropionic acid)ethylene glycol, trimethylolpropane tris(3-mercaptopropionic acid), tetrakis(3-mercaptopropionic acid) pentaerythritol ester, and hexa(3-mercaptopropionic acid) dipentaerythritol ester.

5. The multi-layer packaging film according to any one of claims 1 to 4, characterized in that: The functional auxiliary agent B is an acrylate monomer containing at least two double bonds, and its molecular weight is 100-2000g / mol; preferably, the functional auxiliary agent B includes one or more of trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanuric acid 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, tricyclohexane dimethanol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, diethylene glycol dimethacrylate, and triethylene glycol dimethacrylate.

6. The multi-layer packaging film according to any one of claims 1 to 5, characterized in that: The vinyl copolymer includes but is not limited to one or more of ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, and ethylene-1-decene copolymer, and has a melt index of 1-40 g / 10 min and a comonomer mass insertion rate of 5-60 wt%.

7. The multi-layer packaging film according to any one of claims 1 to 6, characterized in that: The vinyl copolymer includes one or more of ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, and ethylene-1-decene copolymer, and has a melt index of 1-40g / 10min and a comonomer mass insertion rate of 5-60wt%.

8. The multi-layer packaging film according to any one of claims 1 to 7, characterized in that: The crosslinking agent includes one or more of tert-butyl peroxy isopropyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl peroxy 2-ethylhexyl carbonate, tert-amyl peroxy 2-ethylhexyl carbonate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amyl peroxy carbonate, and tert-butyl peroxy 3,3,5-trimethylhexanoate; and / or, the crosslinking agent includes one or more of tert-butyl peroxy carbonate, and tert-butyl peroxy 3,3,5-trimethylhexanoate; The cross-linking auxiliary agent includes one or more of cyanuric acid triacrylate, isocyanuric acid triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane trimethacrylate, triethylene glycol dimethacrylate, tripropylene glycol diacrylate, diethylene glycol dimethacrylate, and ethylene glycol dimethacrylate.

9. The multilayer packaging film according to any one of claims 1 to 8, wherein the unlaminated crosslinking degree of the film is between 5% and 20%, the T90 measured under the lamination conditions of 145°C and 15 minutes is less than 11 minutes, the crosslinking degree is greater than 80%, and the initial peel strength with glass is greater than 200 N / cm.

10. A method for preparing the multilayer encapsulation film according to any one of claims 1 to 9, comprising the following steps: The upper surface layer, lower surface layer and middle layer formula materials are mixed separately, melt extruded by three single screw extruders, the extrusion temperature is 70-90℃, the screw speed of 25-40mm diameter is 5-15r / min, and the three-layer film is cast by the traction roller according to the upper surface layer / middle layer / lower surface layer through the die head distributor. The thickness of the film surface layer is 0.05-0.15mm, and the thickness of the middle layer is 0.1-0.4mm. During the casting and winding process, it is irradiated with UV ultraviolet light, and the irradiation dose is 5-10J / cm 2 , continuous irradiation time 50 to 100 seconds.

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