POE encapsulant film, preparation method therefor and use thereof

Abstract

The present application provides a POE encapsulant film, a preparation method therefor, and a use thereof. The raw material of the POE encapsulant film comprises a polyolefin resin and an additive. The polyolefin resin comprises a modified polyolefin resin and optionally a first unmodified polyolefin resin. The raw material of the modified polyolefin resin comprises a second unmodified polyolefin resin, an active monomer, and an initiator. In the present application, by controlling the number of carbon atoms in side chains and the range of surface energy of the modified polyolefin resin, the polarity of the resin is improved, and the compatibility of the polyolefin resin and the additive in the POE encapsulant film is improved, thereby improving the adsorption effect of the resin on the additive, and the additive can be uniformly distributed in the encapsulant film, thereby reducing the degree of migration of the additive during the storage and use of the POE encapsulant film, effectively avoiding the problems of bubble formation and delamination in the POE encapsulant film during encapsulation and lamination, and improving the quality of the encapsulant film.

Description

POE encapsulation adhesive film, preparation method and application thereof

[0001] This application claims priority to Chinese patent application 2024108629937 with a filing date of June 28, 2024. This application incorporates the entirety of the aforementioned Chinese patent application. TECHNICAL FIELD

[0002] The present application relates to the field of photovoltaic technology, in particular, to a POE encapsulation adhesive film, a preparation method and application thereof. BACKGROUND

[0003] Polyolefin elastomer (POE) is a kind of polymer copolymerized by olefin monomers, mainly composed of saturated carbon hydrogen. POE has excellent water resistance, high light transmittance and easy processing performance, and is widely used in the field of encapsulation of solar cells. With the continuous development of solar cell technology, the performance requirements of encapsulation adhesive film are also getting higher and higher. The overall performance of POE encapsulation adhesive film is better than that of EVA encapsulation adhesive film, so in recent years the proportion of POE encapsulation adhesive film has been increasing year by year.

[0004] When POE is used as an encapsulation adhesive film, various functional additives need to be added to improve its processability, rheological properties, ultraviolet stability, adhesion properties, etc. to meet the various performance requirements in different application scenarios. However, since polyolefin material is composed of saturated carbon hydrogen and does not contain active groups, the compatibility with most functional additives is poor, and the additives mixed in POE are not easy to remain in POE. During storage and use, the additives are easy to migrate to the surface of the film, which can cause problems such as bubbles and delamination during encapsulation lamination, reducing the production yield of the encapsulation adhesive film.

[0005] Based on such problems, it is necessary to provide a POE encapsulation adhesive film, a preparation method and application thereof to develop a POE encapsulation adhesive film with higher performance and more extensive applicability. SUMMARY

[0006] The main purpose of the present application is to provide a POE encapsulation adhesive film, a preparation method and application thereof to improve the problem of poor compatibility of polyolefin with additives and easy precipitation of additives to the surface of the adhesive film in the prior art.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a POE packaging adhesive film is provided, raw materials of the POE packaging adhesive film include polyolefin resin and additives, the polyolefin resin includes modified polyolefin resin and optional first unmodified polyolefin resin; raw materials of the modified polyolefin resin include second unmodified polyolefin resin, active monomer and initiator; the side carbon chain of the modified polyolefin resin is acrylate with carbon atom number of 4-18; and / or the surface energy of the modified polyolefin resin is 45-55 mN / m; and / or the adsorption amount of the modified polyolefin resin to the additives is 17-22 mg / g.

[0008] Further, the first unmodified polyolefin resin and the second unmodified polyolefin resin are independently ethylene-octene copolymer and / or ethylene-butene copolymer; and / or the active monomer is one or more of vinyl acetate, butyl acrylate, isooctyl acrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, dodecyl acrylate, allyl methacrylate and hydroxyethyl acrylate; and / or the initiator is one or more of dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, di-tert-butyl peroxide, di-tert-amyl peroxide and tert-butylperoxy-2-ethylhexyl tert-butyl carbonate.

[0009] Further, in the raw materials of the modified polyolefin resin, the weight ratio of the second unmodified polyolefin resin to the active monomer is 100:(0.5-6); and / or the weight ratio of the second unmodified polyolefin resin to the initiator is 100:(0.05-1.0); and / or in the POE packaging adhesive film, the weight ratio of the modified polyolefin resin to the first unmodified polyolefin resin is (30-100):(0-70).

[0010] Further, in the raw materials of the modified polyolefin resin, the second unmodified polyolefin resin is 100 parts, the active monomer is 1.5-5.0 parts, and the initiator is 0.1-0.5 parts by weight; preferably, in the raw materials of the modified polyolefin resin, the second unmodified polyolefin resin is 100 parts, the active monomer is 2-4 parts, and the initiator is 0.1-0.4 parts.

[0011] Further, the preparation method of the modified polyolefin resin includes the following steps: mixing the second unmodified polyolefin resin, the active monomer and the initiator, and obtaining the modified polyolefin resin by melt extrusion or irradiation; preferably, the reaction zone temperature of the melt extrusion is 150-230℃; and / or the rotation speed of the melt extrusion is 100-250 rpm; and / or the irradiation ray is ultraviolet light and / or electron beam.

[0012] Further, the modified polyolefin resin has a melt index of 3 to 17 g / min; and / or the modified polyolefin resin has a melting point of 50 to 80 °C; and / or the modified polyolefin resin has a grafting ratio of 0.4 to 3.0%.

[0013] Further, the auxiliary agent includes one or more of a crosslinking agent, a co-crosslinking agent, a silane coupling agent, an antioxidant, and a light stabilizer; preferably, the crosslinking agent includes one or more of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-(bis-tert-butylperoxy) 3,3,5-trimethylcyclohexane, tert-butyl peroxybenzoate, triphenylmethane-4,4',4"-triisocyanate, dicumyl peroxide, bis(2-tert-butylperoxyisopropyl)benzene, tert-butyl cumyl peroxide, tert-amyl peroxybenzoate, di-tert-amyl peroxide, tert-butylperoxy benzoate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxy-3,5,5-trimethylhexanoate, di(4-chlorobenzoyl) peroxide, di(2,4-dichlorobenzoyl) peroxide, di(4-methylbenzoyl) peroxide, n-butyl-4,4-bis(tert-butylperoxy) valerate, ethyl-3,3-bis(tert-butylperoxy) butyrate, and tert-butylperoxy-2-ethylhexyl carbonate; and / or the co-crosslinking agent includes one or more of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, and pentaerythritol tetramethacrylate; and / or the silane coupling agent includes one or more of vinyltrimethoxysilane, vinyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, methacrylate silane, and vinyltriisopropoxysilane; and / or the antioxidant includes one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester, n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate; and / or the light stabilizer includes one or more of bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, poly(butylene succinate) (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol), 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, and 2,4-dihydroxybenzophenone.

[0014] Further, in the raw material of the POE encapsulation adhesive film, the polyolefin resin is 100 parts by weight, and in the additive, the crosslinking agent is 0.1-2 parts by weight; and / or the auxiliary crosslinking agent is 0.1-2 parts by weight; and / or the silane coupling agent is 0.1-5 parts by weight; and / or the antioxidant is 0.05-1 parts by weight; and / or the light stabilizer is 0.05-1 parts by weight; preferably, in the raw material of the POE encapsulation adhesive film, the additive includes 0.5-1 parts of the crosslinking agent, 0.5-1.5 parts of the auxiliary crosslinking agent, 0.5-2 parts of the silane coupling agent, 0.05-1 parts of the antioxidant, and 0.05-0.5 parts of the light stabilizer; more preferably, in the raw material of the POE encapsulation adhesive film, 100 parts of the polyolefin resin includes 30-100% of the modified ethylene-octene copolymer resin and the rest of the unmodified ethylene-octene copolymer resin, and the additive includes 0.5-1 parts of tert-butyl peroxy-2-ethylhexyl carbonate, 0.5-1.5 parts of triallyl isocyanurate, 0.5-1.5 parts of vinyltrimethoxysilane, 0.05-0.5 parts of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, and 0.05-0.5 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0015] According to another aspect of the present application, a preparation method of the POE encapsulation adhesive film is provided, including the following steps: mixing the modified polyolefin resin, the additive, and the optional first unmodified polyolefin resin, and film forming to obtain the POE encapsulation adhesive film.

[0016] Further, the film forming temperature is 75-110°C; and / or the film forming mode is double-screw extrusion and / or single-screw extrusion; and / or the thickness of the POE encapsulation adhesive film is 0.01-1.0 mm.

[0017] According to another aspect of the present application, the application of the above-mentioned encapsulation adhesive film is provided, and a photovoltaic module containing the POE encapsulation adhesive film is provided.

[0018] The present application can improve the polarity of the resin, improve the compatibility of the polyolefin resin and the additive in the POE encapsulation adhesive film, improve the adsorption effect of the resin on the additive, make the additive uniformly distributed in the encapsulation adhesive film, reduce the migration degree of the additive in the storage and use of the POE encapsulation adhesive film, effectively avoid the problems such as bubbles and delamination in the encapsulation lamination process of the POE encapsulation adhesive film, and improve the quality of the encapsulation adhesive film. DETAILED DESCRIPTION

[0019] It should be noted that the embodiments and features in the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments.

[0020] Terminology:

[0021] Surface energy: refers to the work required to increase the surface area of a solid, i.e. the energy consumed to break intermolecular forces when creating the surface of the substance. If the surface energy is high, the tendency to attract other molecules is higher.

[0022] Melt index: represents the amount of material melted per unit time at a certain temperature and pressure, usually expressed in g / 10min or g / min, used to describe the melting performance of the material during heating. The higher the melt index, the faster the material melts under the same conditions, and the better the melting performance. The determination method of the melt index in the present application is based on the test standard GB / T 3682.1~2-2018 (or ASTM D1238).

[0023] Grafting rate: the ratio of the mass of monomers grafted onto the polymer molecular chain to the mass of the polymer.

[0024] As described in the background of the present application, there is a problem in the prior art that the compatibility of polyolefin and the auxiliary agent is poor, and the auxiliary agent is easy to precipitate to the surface of the adhesive film. In order to solve the above problem, in a typical embodiment of the present application, a POE packaging adhesive film is provided. The raw materials of the POE packaging adhesive film include polyolefin resin and auxiliary agent, and the polyolefin resin includes modified polyolefin resin and optional first unmodified polyolefin resin; the raw materials of the modified polyolefin resin include second unmodified polyolefin resin, active monomer and initiator; the side carbon chain of the modified polyolefin resin is a propenoic acid ester with a carbon atom number of 4-18; and / or the surface energy of the modified polyolefin resin is 45-55 mN / m; and / or the adsorption amount of the modified polyolefin resin to the auxiliary agent is 17-22 mg / g. The first unmodified polyolefin resin and the second unmodified polyolefin resin can be the same or different.

[0025] The present application limits the side carbon chain of the modified polyolefin resin to be an acrylate with a carbon atom number of 4-18, because the inventors unexpectedly found that, using the second unmodified polyolefin resin, the active monomer and the initiator as raw materials to obtain the modified polyolefin resin, while controlling the side carbon chain of the modified polyolefin resin to be an acrylate with a carbon atom number of 4-18, the polarity of the polyolefin resin can be effectively improved, the polarity of the polyolefin resin and the additive is similar, thereby effectively improving the adsorption amount of the additive by the polyolefin resin, making the additive uniformly distributed in the encapsulation adhesive film, and further effectively reducing the precipitation degree of the additive. If the carbon atom number of the side carbon chain of the modified polyolefin resin is too large, the side chain crystallization tendency may be increased, thereby being not conducive to improving the adsorption effect of the polyolefin resin and the additive; if the carbon atom number of the side carbon chain of the modified polyolefin resin is too small, the carbon chain is too short (such as the side carbon chain is acrylic acid or methacrylic acid), which may make the polarity of the modified polyolefin resin higher, and the polarity difference with the common additive is large, which is also not conducive to improving the adsorption effect of the additive.

[0026] In addition, the inventors unexpectedly found that the surface energy of the modified polyolefin resin is related to both the polarity of the active monomer itself and the grafting concentration of the active monomer, and when the surface energy of the modified polyolefin resin is 45-55 mN / m, the adsorption effect of the additive can be effectively improved. In addition, the present application particularly limits the additive adsorption amount of the modified polyolefin resin to be 17-22 mg / g, within this range, on the one hand, the high additive adsorption amount can be ensured, and on the other hand, the resin flowability will not be greatly affected, which is conducive to improving the processing performance of the product. If the additive adsorption amount of the modified polyolefin resin is too low, the adsorption effect of the additive will be adversely affected; when it is too high, it means that the side carbon proportion of the modified polyolefin resin is too high, although the additive adsorption amount is further improved, but the resin flowability may be significantly reduced, and the resin is prone to appear microgel state, which is not conducive to processing.

[0027] The POE encapsulation adhesive film meeting the above conditions has good compatibility between the polyolefin resin and the additive, the additive can be uniformly distributed in the encapsulation adhesive film, which is conducive to reducing the migration degree of the additive during storage and use of the POE encapsulation adhesive film, can effectively avoid the problems such as bubbles and delamination of the POE encapsulation adhesive film during the encapsulation lamination process, and further can improve the quality of the encapsulation adhesive film.

[0028] In a preferred embodiment, the first unmodified polyolefin resin and the second unmodified polyolefin resin are independently ethylene-octene copolymer and / or ethylene-butene copolymer; and / or the active monomer is one or more of vinyl acetate, butyl acrylate, isooctyl acrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, dodecyl acrylate, allyl methacrylate and hydroxyethyl acrylate; and / or the initiator is one or more of dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, di-tert-butyl peroxide, di-tert-amyl peroxide and tert-butylperoxy-2-ethylhexyl tert-butyl carbonate. Preferably, the second unmodified polyolefin resin is ethylene-octene copolymer, the active monomer is isooctyl acrylate and the initiator is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane. Preferably, the first unmodified polyolefin resin has a melt index of 15 g / 10 min. Preferably, the second unmodified polyolefin resin has a melt index of 15 g / 10 min.

[0029] The modified polyolefin acid ester prepared from the second unmodified polyolefin resin, the active monomer and the initiator of the above kind has a more suitable side carbon chain length, a more similar polarity to the additive and a better compatibility with the additive, thereby having a better adsorption effect on the additive and further reducing the migration of the additive during storage and use of the POE packaging adhesive film, and further improving the quality of the packaging adhesive film.

[0030] In order to further improve the grafting rate of the polyolefin resin and thereby more effectively change the polarity of the polyolefin resin, to further improve the compatibility and adsorption effect of the polyolefin resin on the additive, in a preferred embodiment, the weight ratio of the second unmodified polyolefin resin to the active monomer in the raw materials of the modified polyolefin resin is 100:(0.5-6); and / or the weight ratio of the second unmodified polyolefin resin to the initiator is 100:(0.05-1.0). In a preferred embodiment, the weight ratio of the modified polyolefin resin to the first unmodified polyolefin resin in the POE packaging adhesive film is (30-100):(0-70).

[0031] Further based on similar reasons, in a preferred embodiment, in the raw materials of the modified polyolefin resin, the second unmodified polyolefin resin is 100 parts, the active monomer is 1.5-5.0 parts and the initiator is 0.1-0.5 parts by weight; preferably, in the raw materials of the modified polyolefin resin, the second unmodified polyolefin resin is 100 parts, the active monomer is 2-4 parts and the initiator is 0.1-0.4 parts. More preferably, the raw materials of the modified polyolefin resin include 100 parts of ethylene-octene copolymer, 1.5-5 parts of isooctyl acrylate and 0.1-0.5 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

[0032] In a preferred embodiment, the method for preparing the modified polyolefin resin comprises the following steps: mixing the second unmodified polyolefin resin, the active monomer, and the initiator, and obtaining the modified polyolefin resin through melt extrusion or irradiation; preferably, the temperature of the reaction zone of the melt extrusion is 150-230°C; and / or the rotation speed of the melt extrusion is 100-250 rpm; and / or the irradiation modification uses ultraviolet light and / or electron beam as the radiation; and / or the irradiation is carried out in a nitrogen atmosphere.

[0033] Under the above conditions, the process of the modified polyolefin resin is less, the operation is simpler, the cost is lower, the grafting rate of the obtained modified polyolefin resin is higher, and the adsorption effect on the additives is more obvious.

[0034] In order to further improve the flowability of the encapsulation adhesive film and the bonding strength to the photovoltaic module, in a preferred embodiment, the melt index of the modified polyolefin resin is 3-17 g / min; and / or the melting point of the modified polyolefin resin is 50-80°C. In a preferred embodiment, the grafting rate of the modified polyolefin resin is 0.4-3.0%, and under the above conditions, the polarity of the modified polyolefin resin to the additives is closer, and the adsorption effect on the additives is better.

[0035] In a preferred embodiment, the additives include one or more of a crosslinking agent, a co-crosslinking agent, a silane coupling agent, an antioxidant, and a light stabilizer. In order to more favorably improve the crosslinking uniformity of the resin, improve the cohesive strength of the POE encapsulation adhesive film, and more favorably improve the peel strength of the adhesive film, in a preferred embodiment, the crosslinking agent includes one or more of 2,5-dimethyl-2,5-bis(tert-butyl peroxy)hexane, 1,1-(bis-tert-butyl peroxy) 3,3,5-trimethyl cyclohexane, tert-butyl peroxybenzoate, triphenylmethane-4,4',4"-triisocyanate, dicumyl peroxide, bis(2-tert-butyl peroxy isopropyl) benzene, tert-butyl cumyl peroxide, tert-amyl peroxybenzoate, di-tert-amyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethyl hexanoate, tert-butyl peroxy-3,5,5-trimethyl hexanoate, di(4-chlorobenzoyl) peroxide, di(2,4-dichlorobenzyl) peroxide, di(4-methylbenzoyl) peroxide, n-butyl-4,4-bis(tert-butyl peroxy) valerate, ethyl-3,3-bis(tert-butyl peroxy) butyrate, and tert-butyl peroxy-2-ethyl hexyl carbonate; and / or the co-crosslinking agent includes one or more of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane triacrylate, trimethylolpropane triacrylate, and pentaerythritol tetramethacrylate.

[0036] To further improve the adhesion between the encapsulant film and the photovoltaic module, in a preferred embodiment, the silane coupling agent comprises one or more of vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, methacrylate silane and vinyltriisopropoxysilane.

[0037] To further improve the anti-aging performance of the encapsulant film, in a preferred embodiment, the antioxidant comprises one or more of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate; and / or the light stabilizer comprises one or more of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, poly(butylene succinate)(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol) ester, 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone and 2,4-dihydroxybenzophenone.

[0038] In a preferred embodiment, in the raw materials of the POE encapsulant film, the polyolefin resin is 100 parts by weight, and in the additives, the crosslinking agent is 0.1-2 parts; and / or the co-crosslinking agent is 0.1-2 parts; and / or the silane coupling agent is 0.1-5 parts; and / or the antioxidant is 0.05-1 part; and / or the light stabilizer is 0.05-1 part; preferably, in the raw materials of the POE encapsulant film, the additives comprise 0.5-1 part of the crosslinking agent, 0.5-1.5 parts of the co-crosslinking agent, 0.5-2 parts of the silane coupling agent, 0.05-1 part of the antioxidant and 0.05-0.5 part of the light stabilizer by weight. Under the above conditions, the compatibility between the additives and the resin is better, the comprehensive performance of the POE encapsulant film is better, the adhesion between the POE encapsulant film and the photovoltaic module can be further improved, and the flowability is also improved.

[0039] Further based on similar reasons, in a preferred embodiment, in the raw materials of the POE encapsulant film, 100 parts of the polyolefin resin comprises 30-100% of the modified ethylene-octene copolymer resin and the balance of the unmodified ethylene-octene copolymer resin, and the additives comprise 0.5-1 part of t-butyl peroxy-2-ethylhexyl carbonate, 0.5-1.5 parts of triallyl isocyanurate, 0.5-1.5 parts of vinyl trimethoxysilane, 0.05-0.5 parts of tetra[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, and 0.05-0.5 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0040] In another typical embodiment of the present application, a method for preparing the POE encapsulant film is also provided, comprising the following steps: mixing the modified polyolefin resin, the additives, and optionally the first unmodified polyolefin resin, and film forming to obtain the POE encapsulant film. The method for preparing the POE encapsulant film is simple in operation and has a short process flow, and no additional equipment is needed in the prior art. The compatibility between the additives and the resin is good, the anti-aging performance is strong, the flowability is suitable, the adhesion to the photovoltaic module is good, and the adaptability to the photovoltaic module is stronger.

[0041] In a preferred embodiment, the film forming temperature is 75-110°C; and / or the film forming mode is double-screw extrusion and / or single-screw extrusion; and / or the thickness of the POE encapsulant film is 0.01-1.0 mm. Under the above conditions, the flowability of the POE encapsulant film is more suitable, the crosslinking degree is higher, and the adaptability to the photovoltaic module is better.

[0042] In another typical embodiment of the present application, a photovoltaic module comprising the POE encapsulant film is also provided.

[0043] Typically but not limitedly, the number of chain carbon atoms of the acrylic ester in the side carbon of the modified polyolefin resin is 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or any range value formed by any two of them.

[0044] Typically but not limitedly, the surface energy of the modified polyolefin resin is 45 mN / m, 47 mN / m, 49 mN / m, 50 mN / m, 52 mN / m, 54 mN / m, 55 mN / m, or any range of values between any two of these values; the adsorption amount of the modified polyolefin resin to the additive is 17 mg / g, 19 mg / g, 20 mg / g, 22 mg / g, or any range of values between any two of these values; the melt index of the modified polyolefin resin is 3 g / min, 5 g / min, 7 g / min, 9 g / min, 10 g / min, 12 g / min, 14 g / min, 16 g / min, 17 g / min, or any range of values between any two of these values; the melting point of the modified polyolefin resin is 50 °C, 60 °C, 70 °C, 80 °C, or any range of values between any two of these values; the grafting rate of the modified polyolefin resin is 0.4%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, or any range of values between any two of these values.

[0045] Typically but not limitedly, in the POE encapsulation film, the weight ratio of the second unmodified polyolefin resin to the active monomer is 100:0.5, 100:1, 100:1.5, 100:2, 100:3, 100:4, 100:5, 100:6, or any range of values between any two of these values; the weight ratio of the second unmodified polyolefin resin to the initiator is 100:0.05, 100:0.1, 100:0.2, 100:0.4, 100:0.5, 100:0.6, 100:0.8, 100:1, or any range of values between any two of these values.

[0046] Typically but not limitedly, in 100 parts of the polyolefin resin, the weight ratio of the modified polyolefin resin to the first unmodified polyolefin resin is 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, 90:10, 100:0, or any range of values between any two of these values.

[0047] Typically but not limitedly, the film-forming temperature is 75 °C, 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, or any range of values between any two of these values.

[0048] The application will be further described in conjunction with specific examples, which are not to be construed as limiting the scope of the application as claimed.

[0049] Example 1

[0050] 100 parts of the second unmodified polyolefin resin (ethylene-octene copolymer, melt index 15 g / 10 min, Dow Chemical), 3 parts of active monomer (isooctyl acrylate), 0.2 parts of initiator (2,5-dimethyl-2,5-bis(tert-butyl peroxy) hexane) were mixed, and the mixture was subjected to melt extrusion by means of a twin-screw extruder under the conditions of a reaction temperature interval of 200°C and a rotation speed of 200 rpm to obtain a modified polyolefin resin. The surface energy of the modified polyolefin resin was 49 mN / m, the melt index was 10 g / min, the melting temperature was 60°C, the grafting rate was 1.6%, and the adsorption amount of the additive was 20 mg / g.

[0051] 100 parts of the modified ethylene-octene copolymer resin, 1.0 part of tert-butyl peroxy-2-ethylhexyl carbonate, 1.0 part of triallyl isocyanurate, 2.0 parts of γ-methacryloyloxypropyl trimethoxysilane, 0.1 part of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, and 0.1 part of bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate were mixed to obtain a mixture, and a film was prepared from the mixture at 90°C to obtain a POE packaging adhesive film with a thickness of 0.6 mm.

[0052] The additive retention capacity of the polyolefin resin was evaluated by the following method:

[0053] In step S1, 2.5 g of the polyolefin resin was weighed into a 100-mesh stainless steel filter bag, and the mass of the stainless steel bag was recorded as M0. The total mass of the stainless steel bag and the polyolefin resin was M1. When the polyolefin resin was in the form of particles, the particle size was ensured to be uniform. When the polyolefin resin was in the form of a film, the thickness was ensured to be uniform, and the film was not embossed.

[0054] In step S2, the filter bag was completely immersed in the additive, and the treatment was carried out at a constant temperature of 45°C for 6 hours.

[0055] In step S3, the filter bag was washed in methanol solvent by means of immersion and lifting for 15 times, and the solvent was changed every 5 times to quickly wash away the additive that was not stably absorbed on the surface of the polyolefin resin particles or film.

[0056] In step S4, the polyolefin resin was blown dry with nitrogen gas at a flow rate of 20 L / min until the surface of the sample was completely free of liquid. Then, the blowing was continued at the same gas flow rate for 1 min, and the total mass of the stainless steel bag and the polyolefin resin at this time was recorded as M2.

[0057] In step S5, the additive adsorption amount A of the polyolefin resin was calculated according to A q = (M2-M1) / (M1-M0) q , and the unit was mg / g.

[0058] Example 2

[0059] Example 1 except that the active monomer is selected to be vinyl acetate.

[0060] Example 3

[0061] Example 1 except that the active monomer is selected to be dodecyl acrylate.

[0062] Example 4

[0063] Example 1 except that the initiator is selected to be dicumyl peroxide.

[0064] Example 5

[0065] Example 1 except that the initiator is selected to be di-t-butyl peroxide.

[0066] Example 6

[0067] Example 1 except that the second unmodified polyolefin resin is selected to be an ethylene-butene copolymer resin (melt index of 15 g / 10 min, Dow).

[0068] Example 7

[0069] Example 1 except that the isooctyl acrylate is 0.5 parts and the 2,5-dimethyl-2,5- bis(t-butylperoxy)hexane is 0.05 parts.

[0070] The resulting modified polyolefin resin has a grafting of 0.4% and an additive adsorption of 17 mg / g.

[0071] Example 8

[0072] Example 1 except that the isooctyl acrylate is 6 parts and the 2,5-dimethyl-2,5- bis(t-butylperoxy)hexane is 1.0 parts.

[0073] The resulting modified polyolefin resin has a grafting of 3.0% and an additive adsorption of 22 mg / g.

[0074] Example 9

[0075] Example 1 except that the isooctyl acrylate is 1.5 parts and the 2,5-dimethyl-2,5- bis(t-butylperoxy)hexane is 0.15 parts.

[0076] The resulting modified polyolefin resin has a grafting of 0.8% and an additive adsorption of 18 mg / g.

[0077] Example 10

[0078] The difference between Example 1 and this example is that isooctyl acrylate is 5 parts and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane is 0.6 parts.

[0079] The grafting ratio of the modified polyolefin resin obtained is 2.4% and the additive adsorption amount is 21.2 mg / g.

[0080] Example 11

[0081] The difference between Example 1 and this example is that isooctyl acrylate is 4 parts and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane is 0.25 parts.

[0082] The grafting ratio of the modified polyolefin resin obtained is 1.9% and the additive adsorption amount is 20.5 mg / g.

[0083] Example 12

[0084] The difference between Example 1 and this example is that the temperature of the reaction section of the melt extruder is 150°C and the rotation speed is 100 rpm.

[0085] Example 13

[0086] The difference between Example 1 and this example is that the temperature of the reaction section of the melt extruder is 230°C and the rotation speed is 250 rpm.

[0087] Example 14

[0088] The difference between Example 1 and this example is that the method for preparing the modified polyolefin resin is different; 100 parts of the second unmodified polyolefin resin (ethylene-octene copolymer), 3 parts of isooctyl acrylate and 0.2 parts of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane are mixed and then the modified polyolefin resin is obtained by irradiation under electron beam, in a nitrogen atmosphere and at an energy of 0.05 MeV.

[0089] Example 15

[0090] The difference between Example 14 and this example is that the method for preparing the modified polyolefin resin is different; the corresponding modified polyolefin resin is obtained after electron irradiation at an energy of 0.1 MeV.

[0091] Example 16

[0092] The difference between Example 1 and this example is that the crosslinking agent is selected to be tert-butyl peroxy-3,5,5-trimethylhexanoate instead of tert-butyl peroxy-2-ethylhexyl carbonate.

[0093] Example 17

[0094] The difference between Example 1 and this example is that the co-crosslinking agent is selected to be triallyl cyanurate instead of triallyl isocyanurate.

[0095] Example 18

[0096] The difference from Example 1 is only in the selection of the auxiliary agents, 0.1 part of t-butyl peroxy-2-ethylhexyl carbonate, 0.1 part of triallyl isocyanurate, 0.1 part of γ-methacryloxypropyl trimethoxysilane, 1 part of tetra[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, 0.5 part of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0097] Example 19

[0098] The difference from Example 1 is only in the selection of the auxiliary agents, 2 parts of t-butyl peroxy-2-ethylhexyl carbonate, 2 parts of triallyl isocyanurate, 5 parts of γ-methacryloxypropyl trimethoxysilane, 1 part of tetra[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, 1 part of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0099] Example 20

[0100] The difference from Example 1 is only in the selection of the auxiliary agents, 0.5 parts of t-butyl peroxy-2-ethylhexyl carbonate, 0.5 parts of triallyl isocyanurate, 0.5 parts of γ-methacryloxypropyl trimethoxysilane, 0.05 parts of tetra[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, 0.05 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0101] Example 21

[0102] The difference from Example 1 is only in the selection of the auxiliary agents, 1.0 part of t-butyl peroxy-2-ethylhexyl carbonate, 1.5 parts of triallyl isocyanurate, 1.5 parts of γ-methacryloxypropyl trimethoxysilane, 0.5 parts of tetra[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, 0.5 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0103] Example 22

[0104] The difference from Example 1 is only in the selection of the auxiliary agents, 1.0 part of t-butyl peroxy-2-ethylhexyl carbonate, 1.5 parts of triallyl isocyanurate, 1.5 parts of γ-methacryloxypropyl trimethoxysilane, 0.5 parts of tetra[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, 0.5 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0105] Example 23

[0106] The difference from Example 1 is only in the selection of the auxiliary agents, 1.0 part of t-butyl peroxy-2-ethylhexyl carbonate, 1.5 parts of triallyl isocyanurate, 1.5 parts of γ-methacryloxypropyl trimethoxysilane, 0.5 parts of tetra[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, 0.5 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0107] Example 24

[0108] The difference from Example 1 is that 30 parts of the modified ethylene-octene copolymer resin, 70 parts of the first unmodified polyolefin resin (ethylene-octene copolymer, melt index of 15 g / 10 min, Dow), 1.0 part of t-butyl peroxy-2-ethylhexyl carbonate, 1.0 part of triallyl isocyanurate, 2.0 parts of γ-methacryloxypropyltrimethoxysilane, 0.1 part of tetrakis[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, and 0.1 part of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate are mixed to obtain a mixture, and a film is prepared at 90°C to obtain a POE encapsulant film of 0.6 mm.

[0109] Example 25

[0110] The difference from Example 1 is that 60 parts of the modified ethylene-octene copolymer resin, 40 parts of the first unmodified polyolefin resin (ethylene-butene copolymer, melt index of 15 g / 10 min, Dow), 1.0 part of t-butyl peroxy-2-ethylhexyl carbonate, 1.0 part of triallyl isocyanurate, 2.0 parts of γ-methacryloxypropyltrimethoxysilane, 0.1 part of tetrakis[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, and 0.1 part of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate are mixed to obtain a mixture, and a film is prepared at 90°C to obtain a POE encapsulant film of 0.6 mm.

[0111] Comparative Example 1

[0112] The difference from Example 1 is that the polyolefin resin is not modified. 100 parts of the second unmodified polyolefin resin (ethylene-octene copolymer, melt index of 15 g / 10 min, Dow), 1.0 part of t-butyl peroxy-2-ethylhexyl carbonate, 1.0 part of triallyl isocyanurate, 2.0 parts of γ-methacryloxypropyltrimethoxysilane, 0.1 part of tetrakis[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, and 0.1 part of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate are mixed to obtain a mixture, and a film is prepared at 90°C to obtain a POE encapsulant film of 0.6 mm.

[0113] Comparative Example 2

[0114] The difference from Example 1 is that the kind of active monomer is different, and is 1,4-hexadiene.

[0115] Comparative Example 3

[0116] The difference between this example and example 1 is that 100 parts of ethylene-octene copolymer (melt index 15 g / 10 min, Dow), 0.55 parts of t-butyl peroxy carbonate-2-ethylhexyl ester, 0.8 parts of triallyl isocyanurate, 0.5 parts of vinyl trimethoxysilane, and 0.05 parts of beta-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid n-octadecyl ester are used in parts by weight.

[0117] The components of the modified polyolefin resins of the above examples and comparative examples are shown in Table 1, the types of the additives of the examples are shown in Table 2, and the properties of the modified polyolefin resins obtained from the above examples and comparative examples and the test results of the adsorption amount of the additives are shown in Table 3. Among them, example 24 and example 25 use the same method as example 1 to test the adsorption amount of the additives of the mixture of the modified polyolefin resin and the first unmodified polyolefin resin.

[0118] Test methods:

[0119] Surface energy: tested according to the standard DIN ISO 8296-2008;

[0120] Adsorption amount of additives: tested under constant temperature water bath conditions;

[0121] Melt index: tested according to GB / T 3682.1-2-2018, the test temperature is 190°C, and the load is 2.16 Kg;

[0122] Grafting rate and modification rate: tested according to the method of Chinese application CN110441253A, and the grafting rate is tested by FTIR. The specific test method is as follows: ① a series of grafted samples with different grafting rates are prepared, the total feed quality of the sample is W, and the mass of the monomer is m0. ② The sample is purified by dissolving, filtering, extracting, and drying steps to obtain a purified sample, and the sample quality is M1. ③ The grafting rate (G r ) and modification rate (C) of the samples with different grafting rates are calculated, the calculation formula is: C=(M1-W) / m0x100%; G r =(M1-W) / Wx100%. ④ The infrared spectrum of each sample is determined by infrared spectroscopy, and the peak area A of the sample at ~1740 cm -1 and ~1378 cm -1 is recorded by infrared analysis software, denoted as A 1740 and A 1378 , A=A 1740 / A 1378Note: the characteristic peak position of different monomers is different, and the calculation needs to be adjusted according to the peak position of the monomer. 5. Draw the data graph of grafting rate and A ratio measured by infrared spectroscopy, and obtain the standard curve equation by linear fitting. 6. Determine and calculate the A of the sample to be measured, and substitute it into the fitting curve equation to obtain the grafting rate of the sample to be measured.

[0123] Table 1 Note: " / " in the table means the same as example 1.

[0124] Table 2 Note: " / " in the table means the same as example 1.

[0125] Table 3

[0126] As can be seen from the above, compared with the comparative examples, by controlling the number of side carbon chain carbon atoms and the surface energy range of the modified polyolefin resin, the polarity of the resin is improved, which can effectively improve the compatibility of the polyolefin resin and the additive in the POE packaging adhesive film, thereby improving the adsorption effect of the resin on the additive, allowing the additive to be uniformly distributed in the packaging adhesive film, thereby reducing the migration of the additive during storage and use of the POE packaging adhesive film, effectively avoiding the problems of bubbles and delamination during the packaging lamination process of the POE packaging adhesive film, and improving the quality of the packaging adhesive film. In addition, it can be seen that when each process parameter is within the preferred range of the present application, the compatibility of the packaging adhesive film and the additive is better.

[0127] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A POE encapsulation film, characterized by, The raw materials include a polyolefin resin and an additive, the polyolefin resin includes a modified polyolefin resin and optionally a first unmodified polyolefin resin; the raw materials of the modified polyolefin resin include a second unmodified polyolefin resin, an active monomer and an initiator; The side carbon chain of the modified polyolefin resin is an acrylate with a carbon atom number of 4-18; and / or The surface energy of the modified polyolefin resin is 45-55 mN / m; and / or The adsorption amount of the modified polyolefin resin to the additive is 17-22 mg / g.

2. The POE encapsulating adhesive film according to claim 1, wherein, The first unmodified polyolefin resin and the second unmodified polyolefin resin are independently ethylene-octene copolymer and / or ethylene-butene copolymer; and / or The active monomer is one or more of vinyl acetate, butyl acrylate, isooctyl acrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, dodecyl acrylate, allyl methacrylate and hydroxyethyl acrylate; and / or The initiator is one or more of dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, di-tert-butyl peroxide, di-tert-amyl peroxide and tert-butylperoxy-2-ethylhexyl tert-butyl carbonate.

3. The POE encapsulant film according to claim 1 or 2, wherein, In the raw materials of the modified polyolefin resin, The weight ratio of the second unmodified polyolefin resin to the active monomer is 100:(0.5-6); and / or The weight ratio of the second unmodified polyolefin resin to the initiator is 100:(0.05-1.0); and / or In the POE encapsulating adhesive film, the weight ratio of the modified polyolefin resin to the first unmodified polyolefin resin is (30-100):(0-70).

4. The POE encapsulant film according to any one of claims 1 to 3, wherein, In the raw materials of the modified polyolefin resin, the second unmodified polyolefin resin is 100 parts, the active monomer is 1.5-5.0 parts and the initiator is 0.1-0.5 part by weight; preferably, in the raw materials of the modified polyolefin resin, the second unmodified polyolefin resin is 100 parts, the active monomer is 2-4 parts and the initiator is 0.1-0.4 part by weight.

5. The POE encapsulant film according to any one of claims 1 to 4, wherein, The preparation method of the modified polyolefin resin includes the following steps: mixing the second unmodified polyolefin resin, the active monomer and the initiator, and obtaining the modified polyolefin resin by melt extrusion or irradiation; preferably, The reaction zone temperature of the melt extrusion is 150-230℃; and / or The rotation speed of the melt extrusion is 100-250 rpm; and / or The irradiation ray is ultraviolet light and / or electron beam.

6. The POE encapsulating adhesive film according to any one of claims 1-5, wherein, The melt index of the modified polyolefin resin is 3-17 g / min; and / or The melting point of the modified polyolefin resin is 50-80℃; and / or The grafting rate of the modified polyolefin resin is 0.4-3.0%.

7. The POE encapsulant film according to any one of claims 1 to 6, wherein, The additive includes one or more of a crosslinking agent, a co-crosslinking agent, a silane coupling agent, an antioxidant and a light stabilizer. Preferably, the cross-linking agent comprises one or more of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-(bis-tert-butylperoxy) 3,3,5-trimethylcyclohexane, tert-butyl peroxybenzoate, triphenylmethane-4,4',4"-triisocyanate, dicumyl peroxide, bis(2-tert-butylperoxyisopropyl) benzene, tert-butyl cumyl peroxide, tert-amyl peroxybenzoate, di-tert-amyl peroxide, tert-butylperoxybenzoate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxy-3,5,5-trimethylhexanoate, di(4-chlorobenzoyl) peroxide, di(2,4-dichlorobenzoyl) peroxide, di(4-methylbenzoyl) peroxide, n-butyl-4,4-di(tert-butylperoxy) valerate, ethyl-3,3-di(tert-butylperoxy) butyrate, and tert-butylperoxy-2-ethylhexyl carbonate; and / or The co-crosslinking agent comprises one or more of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane triacrylate, trimethylolpropane triacrylate, and pentaerythritol tetramethacrylate; and / or The silane coupling agent comprises one or more of vinyltrimethoxysilane, vinyltriethoxysilane, gamma-methacryloyloxypropyltrimethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, methacrylate silane, and vinyltriisopropoxysilane; and / or The antioxidant comprises one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] pentaerythritol ester, n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate; and / or The light stabilizer comprises one or more of bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, poly(butylene succinate-4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol), 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, and 2,4-dihydroxybenzophenone.

8. The POE encapsulant film of claim 7, wherein, In the raw materials of the POE packaging adhesive film, the polyolefin resin is 100 parts by weight, and the amount of the cross-linking agent in the additives is 0.1-2 parts by weight; and / or the amount of the co-crosslinking agent is 0.1-2 parts by weight; and / or the amount of the silane coupling agent is 0.1-5 parts by weight; and / or the amount of the antioxidant is 0.05-1 parts by weight; and / or the amount of the light stabilizer is 0.05-1 parts by weight; Preferably, in the raw materials of the POE packaging adhesive film, the additives comprise 0.5-1 parts by weight of the cross-linking agent, 0.5-1.5 parts by weight of the co-crosslinking agent, 0.5-2 parts by weight of the silane coupling agent, 0.05-1 parts by weight of the antioxidant, and 0.05-0.5 parts by weight of the light stabilizer. More preferably, in the raw materials of the POE encapsulant film, 100 parts of the polyolefin resin comprises 30-100% of modified ethylene-octene copolymer resin and the balance of unmodified ethylene-octene copolymer resin, and the additives comprise 0.5-1 part of t-butyl peroxy-2-ethylhexyl carbonate, 0.5-1.5 parts of triallyl isocyanurate, 0.5-1.5 parts of vinyl trimethoxysilane, 0.05-0.5 parts of tetra[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, and 0.05-0.5 parts of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, by weight.

9. The method of producing a POE encapsulating adhesive film according to any one of claims 1 to 8, characterized by, comprising the steps of: mixing the modified polyolefin resin, the additives, and optionally the first unmodified polyolefin resin, and film forming to obtain the POE encapsulant film.

10. The method of claim 9, wherein the film forming is performed at a temperature of 75-110°C; and / or the film forming is performed by twin-screw extrusion and / or single-screw extrusion; and / or the POE encapsulant film has a thickness of 0.01-1.0 mm. The photovoltaic module comprises the POE encapsulant film according to any one of claims 1-8. The photovoltaic module comprises the POE encapsulant film according to any one of claims 1-8. ​ 11. A photovoltaic module, characterized by ​

Images