Polyethylene copolymer and terpolymer for solar cell encapsulation and preparation method thereof

Abstract

There is provided a film comprising a polymer composition comprising a polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, in which the ethylene content is in the range of from 40 wt% to 99.9 wt%, and the melt index (I2) measured according to ASTM D1238 (190 DEG C and a load of 2.16 kg) is from 0.1 g / 10 min to 100 g / 10 min. A method of manufacturing the film, an article comprising the film, a solar cell encapsulation material comprising the film, a laminate comprising the film, and a method of manufacturing the article are also provided.

Description

BACKGROUND OF THE INVENTION

[0001] Solar cell encapsulation materials made of ethylene-vinyl acetate (EVA) copolymer have degradation problems, especially in environments with high humidity, high temperature and solar incidence. This can lead to acetic acid formation (causing corrosion of the metal parts of the module), browning (due to chromophore formation, which may lead to reduced light transmittance and light absorbance), and loss of adhesion and flexibility, all of which are detrimental to the performance of solar cells and pose challenges to the goal of a 30-year lifespan.

[0002] Currently, alternatives to EVA are materials such as ionomers, polyolefin elastomers (POE), thermoplastic olefins (TPO), and polysiloxanes (silicones). Although ionomers have superior properties (especially higher resistivity and transmittance, and lower water vapor transmission rate), they are generally more expensive than EVA and thus have less market acceptance. Polydimethylsiloxane (PDMS), the first material used as a photovoltaic (PV) module encapsulation material, has also encountered similar problems. Despite its superior performance (especially in terms of light transmittance), its high cost makes it attractive only for niche, very specific and demanding applications.

[0003] On the other hand, POE, a relatively new material on the market, is used in two ways: cross-linked or as a thermoplastic material. The cross-linked version of these films is made into films using a process similar to that of current EVA films. Peroxides, silanes and additives are blended with the POE polymer, and the mixture is made into a film through an extrusion or calendering process, and is usually designed to be used in the same solar module manufacturing equipment with a production cycle time similar to that of EVA. On the other hand, for the thermoplastic version, the silane additive used to ensure adhesion must be grafted before the film is produced, and mechanical stability at temperatures up to 105 °C must be ensured. By eliminating the degradation mechanism associated with acetic acid from EVA, a longer service life can be achieved. However, POE generally has a lower adhesion ability and will encounter problems such as high cost and availability in the solar market.

[0004] For EVA, the above degradation phenomena are triggered / accelerated by exposure to UV radiation, heat, moisture, oxygen and the catalytic activity of acetic acid. Therefore, there has always been a need for cost-effective materials that can reduce hydrolysis and UV degradation problems. SUMMARY OF THE INVENTION

[0005] The present invention content is provided to introduce a series of concepts that will be further described in the following detailed implementation. The present invention content is neither intended to identify the key or essential features of the claimed subject matter nor intended to help limit the scope of the claimed subject matter.

[0006] In one aspect, embodiments disclosed in this specification relate to a film comprising a polymer composition, the polymer composition comprising a polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, wherein the ethylene content ranges from 40 wt% to 99.9 wt%, and the melt index (I2) measured according to ASTM D1238 (at 190 °C and a load of 2.16 kg) is from 0.1 g / 10 min to 100 g / 10 min.

[0007] In another aspect, embodiments disclosed in this specification relate to a method for producing a film, the film comprising a polymer composition, the polymer composition comprising a polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, wherein the ethylene content ranges from 40 wt% to 99.9 wt% in the polymer, and the melt index (I2) measured according to ASTM D1238 (at 190 °C and a load of 2.16 kg) is from 0.1 g / 10 min to 100 g / 10 min, the method comprising blending the polymer composition, the polymer composition comprising a polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, and optionally: peroxide; crosslinking aid; primary antioxidant; secondary antioxidant; light stabilizer; UV absorber; adhesion promoter; heat stabilizer; plasticizer; rubber / elastomer; filler; and combinations thereof, wherein the blending method comprises: using a twin-screw extruder, single-screw extruder, kneader, internal mixer, mixing roll, or cast film extruder; and producing a film having a thickness in the range of 5 μm to 800 μm via cast film extrusion, blown film extrusion, or calendering.

[0008] In yet another aspect, embodiments disclosed in this specification relate to an article comprising a substrate and a film, the film comprising a polymer composition, the polymer composition comprising a polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, wherein the ethylene content ranges from 40 wt% to 99.9 wt% in the polymer, and the melt index (I2) measured according to ASTM D1238 (at 190 °C and a load of 2.16 kg) is from 0.1 g / 10 min to 100 g / 10 min.

[0009] In another aspect, embodiments disclosed in this specification relate to a solar cell encapsulation material, which comprises a film. The film comprises a polymer composition. The polymer composition comprises a polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate. In the polymer, the ethylene content ranges from 40 wt% to 99.9 wt%, and the melt index (I2) measured according to ASTM D1238 (at 190 °C and a load of 2.16 kg) is from 0.1 g / 10 min to 100 g / 10 min, wherein the film is crosslinked.

[0010] In another aspect, embodiments disclosed in this specification relate to a laminate, which comprises a glass substrate and a film. The film comprises a polymer composition. The polymer composition comprises a polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate. In the polymer, the ethylene content ranges from 40 wt% to 99.9 wt%, and the melt index (I2) measured according to ASTM D1238 (at 190 °C and a load of 2.16 kg) is from 0.1 g / 10 min to 100 g / 10 min, wherein the film is on the glass substrate.

[0011] In another aspect, embodiments disclosed in this specification relate to a method of manufacturing an article, which comprises applying a film on a substrate. The film comprises a polymer composition. The polymer composition comprises a polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate. In the polymer, the ethylene content ranges from 40 wt% to 99.9 wt%, and the melt index (I2) measured according to ASTM D1238 (at 190 °C and a load of 2.16 kg) is from 0.1 g / 10 min to 100 g / 10 min.

[0012] Other aspects and advantages of the claimed subject matter will become apparent from the following description and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Shows a lamination cycle.

[0014] Figure 2 Shows a schematic diagram of a lamination process.

[0015] Figure 3 Shows a laminated sample.

[0016] Figure 4 Shows the initial UV-VIS spectrum of a laminated sample.

[0017] Figure 5 Shows the spectrum of the lamp used in the UV degradation test and the damp heat test.

[0018] Figure 6 Shows the UV degradation test results.

[0019] Figure 7 Shows the transmittance comparison between DV001A and EVATANE.

[0020] Figure 8 Shows the transmittance comparison between DV001B and EVATANE.

[0021] Figure 9 Shows the transmittance comparison between HM728 and EVATANE.

[0022] Figure 10 Shows the index - angular coefficient (m) calculated from the numerical integration data.

[0023] Figure 11 Shows the index - linear coefficient (b) calculated from the numerical integration data.

[0024] Figure 12 Shows the linear coefficient from the measured values (initial transmittance - b0).

[0025] Figure 13 Shows the transmittance of the sample during the damp heat test - 65 °C, 85% relative humidity, UV lamp.

[0026] Figure 14 Shows the transmittance of EVATANE and DV001A during the damp heat test.

[0027] Figure 15 Shows the transmittance of EVATANE and DV001B during the damp heat test.

[0028] Figure 16 Shows the transmittance of EVATANE and HM728 during the damp heat test.

[0029] Figure 17 Shows the initial transmittance of DV001A, DV001B, HM728, and Evatane during the damp heat test.

[0030] Figure 18 Shows the plateau transmittance (linear fit) during the damp heat test.

[0031] Figure 19a Shows the difference - absolute value between the initial transmittance and the plateau transmittance (linear fit) during the damp heat test.

[0032] Figure 19b Shows the difference - normalized value obtained from the initial transmittance between the initial transmittance and the plateau transmittance (linear fit) during the damp heat test.

[0033] Figure 20 Shows a schematic diagram of a laminated adhesion test sample.

[0034] Figure 21 Shows a graph of force versus displacement, highlighting the regions used for work and energy calculations and highlighting the regions not considered by HM728.

[0035] Figure 22 Shows a graph of force versus displacement, highlighting the region used for the average force. Detailed Description

[0036] The embodiments disclosed in this specification relate to a film comprising a polymer composition, the polymer composition comprising a polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, wherein the ethylene content is in the range of 40 wt% to 99.9 wt%. In one or more embodiments, the polymer composition can be prepared by the reaction of ethylene with one or more branched vinyl esters and / or vinyl acetate monomers, and one or more branched vinyl esters and / or vinyl acetate monomers modify various properties of the resulting copolymer and the film formed therefrom, including: density; melt index (I2); melting temperature; resistivity; hardness; softening point; optical transmittance; haze; water vapor transmission performance; mechanical strength; UV cut-off wavelength; gloss; crystallinity; and glass transition temperature, etc.

[0037] Advantageously, the present disclosure aims to reduce the problems associated with the hydrolysis and degradation of the above-mentioned EVA by using copolymers and terpolymers formed from ethylene and branched vinyl esters and optionally vinyl acetate. Adding branched vinyl esters in place of vinyl acetate or in combination with vinyl acetate can reduce the water vapor transmission rate (WVTR) and acetic acid formation while enhancing low-temperature flexibility.

[0038] Polymer Composition

[0039] Copolymers and Terpolymers

[0040] The copolymers and terpolymers of the present disclosure can be produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, wherein the ethylene content is in the range of 40 wt% to 99.9 wt%.

[0041] Branched Vinyl Ester Monomers

[0042] In one or more embodiments, the branched vinyl ester can include a branched vinyl ester produced from an isomeric mixture of a branched alkanoic acid. The branched vinyl ester according to the present disclosure can have the chemical general formula (I):

[0043]

[0044] wherein R 1 , R 2 and R 3 have a total carbon number in the range of C3 to C20. In some embodiments, R 1 , R 2 and R 3 can all be alkyl chains with different degrees of branching in some embodiments, or a subset of R 1 , R 2 and R 3 can independently be selected from the group consisting of hydrogen, alkyl, or aryl in some embodiments.

[0045] In one or more embodiments, the vinyl carbonyl monomer can include a branched vinyl ester having the following general chemical formula (II):

[0046]

[0047] wherein R 4 and R 5 have a total carbon number of 6 or 7, and the number average molecular weight (M n ) of the polymer composition obtained by GPC ranges from 5 kDa to 10000 kDa. In one or more embodiments, R 4 and R 5 can have a total carbon number less than 6 or greater than 7, and the polymer composition can have an M n of up to 10000 kDa. That is, when M n is less than 5 kDa, R 4 and R 5 can have a total carbon number less than 6 or greater than 7, but if M n is greater than 5 kDa, for example, in the range of 5 kDa to 10000 kDa, then R 4 and R 5 can include a total carbon number of 6 or 7. In a specific embodiment, R 4 and R 5 have a total carbon number of 7, and M n can be in the range of 5 kDa to 10000 kDa. Additionally, in one or more specific embodiments, the vinyl carbonyl according to formula (II) can be used in combination with vinyl acetate.

[0048] Examples of the branched vinyl ester can include monomers having the following chemical structures (including their derivatives):

[0049]

[0050] In one or more embodiments, the polymer composition can include a polymer made from monomers derived from petroleum and / or renewable sources.

[0051] In one or more embodiments, the branched vinyl ester can include a monomer and comonomer mixture of vinyl esters containing versatic acid, neodecanoic acid, etc. In some embodiments, the branched vinyl ester can include Versatic TM acids commercially available from Hexion TM chemical company, including Versatic TM acid EH, Versatic TM acid 9, and Versatic TM acid 10. In one or more embodiments, the polymer composition can include a polymer made from monomers derived from petroleum and / or renewable sources.

[0052] The copolymer or terpolymer including the branched vinyl ester according to the present disclosure can contain ethylene, and the weight percentage range of ethylene measured by proton nuclear magnetic resonance ( 1 H NMR) and carbon-13 nuclear magnetic resonance ( 13 C NMR) is from a lower limit selected from one of 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, and 75 wt% to an upper limit selected from one of 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt%, 99 wt%, or 99.9 wt%, where any lower limit can be paired with any upper limit.

[0053] The copolymer or terpolymer including the branched vinyl ester according to the present disclosure can contain vinyl ester monomers (such as the vinyl ester monomers of formulas (I) and (II) above), and the weight percentage range of the vinyl ester monomers measured by 1 H NMR and 13 C NMR is from a lower limit selected from one of 0.01 wt%, 0.1 wt%, 1 wt%, 5 wt%, 10 wt%, 20 wt%, or 30 wt% to an upper limit selected from 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, or 60 wt%, where any lower limit can be paired with any upper limit.

[0054] In some embodiments, the copolymer or terpolymer including the branched vinyl ester according to the present disclosure can optionally contain vinyl acetate, and the vinyl acetate is measured by 1 H NMR and 13The weight percentage range measured by ¹³C NMR is from a lower limit selected from one of 0 wt%, 0.01 wt%, 0.1 wt%, 1 wt%, 5 wt%, 10 wt%, 20 wt% or 30 wt% to an upper limit selected from 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt% or 59.99 wt%, where any lower limit can be paired with any upper limit. For polymer samples containing vinyl acetate monomer and vinyl ester monomer, quantitative 13 ¹³C NMR determination of content can be used because 1 ¹H NMR contains significant overlap in both the carbonyl region and the alkyl region for accurate integration. In 13 the ¹³C NMR spectrum (TCE-D2, 393.1 K, 125 MHz), evidence of branched vinyl ester and vinyl acetate is observed in both the carbonyl region (170 - 180 ppm) and the alkyl region (0 - 50 ppm). 1 The ¹H NMR spectrum (TCE-D2, 393.2 K, 500 MHz) shows peaks for vinyl acetate and branched vinyl ester (4.7 - 5.2 ppm) and ethylene (1.2 - 1.5 ppm), as well as other peaks in the alkyl region (0.5 - 1.5 ppm) indicating long alkyl chains on the branched vinyl ester monomer. The relative intensities of the peaks found in 1 ¹H NMR and 13 ¹³C NMR spectra are used to calculate the monomer content of branched vinyl ester and vinyl acetate in the copolymer / terpolymer.

[0055] The number average molecular weight (M n n) in kDa of the copolymer or terpolymer including branched vinyl ester according to the present disclosure measured by gel permeation chromatography (GPC) can range from a lower limit selected from one of 1 kDa, 5 kDa, 10 kDa, 15 kDa and 20 kDa to an upper limit selected from one of 40 kDa, 50 kDa, 100 kDa, 300 kDa, 500 kDa, 1000 kDa, 5000 kDa and 10000 kDa, where any lower limit can be paired with any upper limit.

[0056] The weight average molecular weight (M w w) in kDa of the copolymer or terpolymer including branched vinyl ester according to the present disclosure measured by GPC can range from a lower limit selected from one of 1 kDa, 5 kDa, 10 kDa, 15 kDa and 20 kDa to an upper limit selected from one of 40 kDa, 50 kDa, 100 kDa, 200 kDa, 300 kDa, 500 kDa, 1000 kDa, 2000 kDa, 5000 kDa, 10000 kDa and 20000 kDa, where any lower limit can be paired with any upper limit.

[0057] The molecular weight distribution (MWD, defined as the ratio of M w to M n ) of the copolymer or terpolymer comprising a branched vinyl ester according to the present disclosure has a lower limit of any one of 1, 1.5, 2, 5 or 10 and an upper limit of any one of 20, 30, 40, 50 or 60, wherein any lower limit can be paired with any upper limit.

[0058] GPC analysis can be carried out in gel permeation chromatography combined with triple detection, wherein the infrared detector IR5 and the four-capillary viscometer are both from PolymerChar, and the octahedral light scattering detector is from Wyatt. A set of 4 chromatographic columns (mixed bed, 13 μm, from Tosoh) can be used, and the temperature is 140 °C. The experiment can be carried out under the following conditions: the concentration is 1 mg / mL, the flow rate is 1 mL / min, the dissolution temperature and time are 160 °C and 90 minutes respectively, and the injection volume is 200 μL. The solvent used is TCB (trichlorobenzene) stabilized with 100 ppm BHT.

[0059] In one or more embodiments, the copolymer or terpolymer comprising a branched vinyl ester monomer according to the present disclosure can be prepared in a reactor by polymerizing ethylene and one or more branched vinyl ester monomers and optionally a vinyl acetate comonomer, as described, for example, in U.S. Patent Publication No. 2021 / 0102014, the entire content of which is incorporated herein by reference. The method of reacting the comonomers in the presence of a free radical initiator can include any suitable method in the art, including solution phase polymerization, pressure radical polymerization, bulk polymerization, emulsion polymerization and suspension polymerization. In some embodiments, the reactor can be a batch autoclave reactor with a temperature below 150 °C and a pressure below 500 bar, which is referred to as a low-pressure polymerization system. In some embodiments, the comonomers and one or more free radical polymerization initiators are polymerized in a continuous or batch process at a temperature above 150 °C and a pressure above 1000 bar, which is referred to as a high-pressure polymerization system. The copolymers and terpolymers produced under high-pressure conditions can have a number average molecular weight of 5 kDa to 40 kDa, a weight average molecular weight of 5 kDa to 400 kDa, and an MWD of 2 to 10.

[0060] In one or more embodiments, the reaction is carried out in a low-pressure polymerization process, in which ethylene and one or more branched vinyl ester monomers and optionally vinyl acetate comonomer are polymerized in the liquid phase of an inert solvent and / or one or more liquid monomers. In one embodiment, the polymerization comprises a radical polymerization initiator in an amount of from about 0.001 millimoles to about 0.01 millimoles, calculated as the total amount of one or more radical polymerization initiators per liter of the volume of the polymerization zone. The amount of ethylene in the polymerization zone will depend primarily on the total pressure in the reactor in the range of about 20 bar to about 100 bar and the temperature in the range of about 20 °C to about 125 °C. The liquid phase of the polymerization process according to the present disclosure may comprise ethylene, one or more branched vinyl ester monomers, optionally vinyl acetate comonomer, radical polymerization initiator, and optionally one or more inert solvents such as tetrahydrofuran (THF), chloroform, dichloromethane (DCM), dimethyl sulfoxide (DMSO), dimethyl carbonate (DMC), hexane, cyclohexane, ethyl acetate (EtOAc), acetonitrile, toluene, xylene, diethyl ether, dioxane, dimethylformamide (DMF), benzene or acetone. Copolymers and terpolymers produced under low-pressure conditions may exhibit a number-average molecular weight of 2 kDa to 20 kDa, a weight-average molecular weight of 4 kDa to 100 kDa, and an MWD of 2 to 5.

[0061] Additive

[0062] In one or more embodiments, the polymer composition according to the present disclosure may comprise one or more additives, including but not limited to crosslinking agents, crosslinking aids, primary antioxidants, secondary antioxidants, light stabilizers, UV absorbers, adhesion promoters, heat stabilizers, plasticizers, rubbers, elastomers, fillers, and combinations thereof.

[0063] Crosslinking agent

[0064] The polymer composition according to the present disclosure may include at least one crosslinking agent, and the at least one crosslinking agent may include one or more peroxides capable of generating free radicals during polymer processing. In one or more embodiments, the peroxides may include: bifunctional peroxides (such as benzoyl peroxide); dicumyl peroxide; di-tert-butyl peroxide; OO-tert-amyl-O-2-ethylhexyl monoperoxycarbonate; tert-butylcumyl peroxide; tert-butyl 3,5,5-trimethylhexanoate peroxide; tert-butyl benzoate peroxide; 2-ethylhexyl carbonate tert-butyl peroxide; 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane; 1,1-di(tert-butylperoxide)-3,3,5-trimethylcyclohexane; 2,5-dimethyl-2,5-di(tert-butylperoxide)hex-3-yne; 3,3,5,7,7-pentamethyl-1,2,4-trioxepane; butyl 4,4-di(tert-butylperoxide)valerate; bis(2,4-dichlorobenzoyl)peroxide; bis(4-methylbenzoyl)peroxide; di(tert-butylperoxyisopropyl)benzene, etc.

[0065] The peroxide may also include benzoyl peroxide, 2,5 - bis(isopropylperoxy)-2,5 - dimethylhexane, 2,5 - bis(isopropylperoxy)-2,5 - dimethylhex-3-yne, 4 - methyl - 4-(tert - butylperoxy)-2 - pentanol, butyl 2 - ethylhexyl peroxydicarbonate, tert - butyl neopentyl peroxydicarbonate, tert - butyl neodecanoate, tert - butyl benzoate, tert - butyl 2 - ethylhexanoate, 4 - methyl - 4-(tert - amylperoxy)-2 - pentanol, 4 - methyl - 4-(cumylperoxy)-2 - pentanol, 4 - methyl - 4-(tert - butylperoxy)-2 - pentanone, 4 - methyl - 4-(tert - amylperoxy)-2 - pentanone, 4 - methyl - 4-(cumylperoxy)-2 - pentanone, 2,5 - dimethyl - 2,5 - bis(tert - butylperoxy)hexane, 2,5 - dimethyl - 2,5 - bis(tert - amylperoxy)hexane, 2,5 - dimethyl - 2,5 - bis(tert - butylperoxy)hex - 3 - yne, 2,5 - dimethyl - 2,5 - bis(tert - amylperoxy)hex - 3 - yne, 2,5 - dimethyl - 2 - tert - butylperoxy - 5 - hydroperoxyhexane, 2,5 - dimethyl - 2 - cumylperoxy - 5 - hydroperoxyhexane, 2,5 - dimethyl - 2 - tert - amylperoxy - 5 - hydroperoxyhexane, m / p - α,α - bis[(tert - butylperoxy)isopropyl]benzene, 1,3,5 - tris(tert - butylperoxyisopropyl)benzene, 1,3,5 - tris(tert - amylperoxyisopropyl)benzene, 1,3,5 - tris(cumylperoxyisopropyl)benzene, bis[1,3 - dimethyl - 3-(tert - butylperoxy)butyl] carbonate, bis[1,3 - dimethyl - 3-(tert - amylperoxy)butyl] carbonate, bis[1,3 - dimethyl - 3-(cumylperoxy)butyl] carbonate, di - tert - amyl peroxide, tert - amyl cumyl peroxide, tert - butyl isopropenyl cumyl peroxide, 2,4,6 - tris(butylperoxy)-s - triazine, 1,3,5 - tris[1-(tert - butylperoxy)-1 - methylethyl]benzene, 1,3,5 - tris[(tert - butylperoxy)-isopropyl]benzene, 1,3 - dimethyl - 3-(tert - butylperoxy)butanol, 1,3 - dimethyl - 3-(tert - amylperoxy)butanol, bis(2 - phenoxyethyl) peroxydicarbonate, bis(4 - tert - butylcyclohexyl) peroxydicarbonate, dilauryl peroxydicarbonate, dibenzyl peroxydicarbonate, di(isobonyl)peroxydicarbonate, 3 - cumylperoxy - 1,3 - dimethylbutyl methacrylate, 3 - tert - butylperoxy - 1,3 - dimethylbutyl methacrylate, 3 - tert - amylperoxy - 1,3 - dimethylbutyl methacrylate, tris(1,3-dimethyl-3-(t-butylperoxy)butoxy)vinylsilane, 1,3-dimethyl-3-(t-butylperoxy)butyl N-[1-{3-(1-methylethenyl)-phenyl)1-methylethyl]carbamate, 1,3-dimethyl-3-(t-amylperoxy)butyl N-[1-{3-(1-methylethenyl)-phenyl}-1-methylethyl]carbamate, 1,3-dimethyl-3-(cumylperoxy))butyl N-[1-{3-(1-methylethenyl)-phenyl}-1-methylethyl]carbamate, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, n-butyl 4,4-bis(t-amylperoxy)valerate, ethyl 3,3-bis(t-butylperoxy)butyrate, 2,2-bis(t-amylperoxy)propane, 3,6,6,9,9-pentamethyl-3-ethoxycabonylmethyl-1,2,4,5-tetraoxacyclononane, n-butyl-4,4-bis(t-butylperoxy)valerate, ethyl 3,3-bis(t-amylperoxy)butyrate, benzoyl peroxide, OO-t-butyl-O-hydrogen-monoperoxy-succinate, OO-t-amyl-O-hydrogen-monoperoxy-succinate, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane (or methylethyl ketone peroxide cyclic trimer), methylethyl ketone peroxide cyclic dimer, 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, t-butyl peroxybenzoate, t-butylperoxy acetate, t-butylperoxy-2-ethyl hexanoate, t-amyl peroxybenzoate, t-amylperoxy acetate, t-butyl peroxyisobutyrate, 3-hydroxy-1,1-tert-butyl peroxy-1,1-dimethylacetate, OO-t-amyl-O-hydrogen-monoperoxy succinate, OO-t-butyl-O-hydrogen-monoperoxy succinate, di-t-butyl diperoxyphthalate, t-butyl peroxy-3,3,5-trimethylhexanoate, 1,4-bis(t-butylperoxycarbo)cyclohexane, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy-(cis-3-carboxy)propionate, allyl 3-methyl-3-t-butylperoxybutyrate, OO-t-butyl-O-isopropylmonoperoxy carbonate, OO-t-butyl-O-(2-ethylhexyl)monoperoxy carbonate, 1,1,1-tris[2-(t-butylperoxycarbonyloxy)ethoxymethyl]propane, 1,1,1-tris[2-(t-amylperoxycarbonyloxy)ethoxymethyl]propane, 1,1,1-tris[2-(cumylperoxycarbonyloxy)ethoxymethyl]propane, OO-t-amyl-O-isopropylmonoperoxy carbonate, bis(4-methylbenzoyl)peroxide, bis(3-methylbenzoyl)peroxide, bis(2-methylbenzoyl)peroxide, dilauroyl peroxide, dibenzoyl peroxide, 2,4-dibromo-benzoyl peroxide, succinic peroxide, bis(2,4-dichlorobenzoyl)peroxide, and combinations thereof.,

[0066] With respect to 100 phr (parts per hundred parts of polymer / rubber / resin), the amount of crosslinking agent can be in the range of from a lower limit of 0.01 phr, 0.1 phr, 0.5 phr, 1 phr or 2 phr to an upper limit of 2 phr, 3 phr, 4 phr or 5 phr, where any lower limit can be used in combination with any suitable upper limit. In one or more embodiments, the crosslinking agent can be in the range of from 0.1 phr to 2.5 phr, or even in an amount of from 0.5 phr to 2 phr.

[0067] Crosslinking aid

[0068] In one or more embodiments, a polymer composition according to the present disclosure may include one or more crosslinking aids. The crosslinking aids create additional reactive sites for crosslinking, such that the degree of polymer crosslinking is significantly increased from that typically obtained by adding only peroxides. Overall, the aids increase the crosslinking rate. In one or more embodiments, the crosslinking aids may include triallyl isocyanurate (TAIC), trimethylolpropane-tris-methacrylate (TRIM), triallyl cyanurate (TAC), trifunctional (meth)acrylate ester (TMA), N,N’-m-phenylene dimaleimide (PDM), poly(butadiene) diacrylate (PBDDA), high vinyl poly(butadiene) (HVPBD), poly-transoctenamer rubber (TOR) and combinations thereof.

[0069] Relative to 100 phr (parts per hundred parts of rubber / resin) of the polymer, the amount of the crosslinking aid may be in the range of from a lower limit of 0.01 phr, 0.1 phr, 0.5 phr, 1 phr or 2 phr to an upper limit of 2 phr, 2.5 phr, 3 phr, 3.5 phr, 4 phr, 4.5 phr or 5 phr, wherein any lower limit may be used in combination with any suitable upper limit. In one or more embodiments, the crosslinking aid may be in the range of 0.1 phr to 2.5 phr.

[0070] Antioxidant

[0071] In one or more embodiments, a polymer composition according to the present disclosure may include one or more antioxidants. The polymer composition according to the embodiments may include at least a primary antioxidant and a secondary antioxidant. The antioxidants according to the present disclosure may include monophenol-type antioxidants, bisphenol-type antioxidants, polymeric phenol-type antioxidants, sulfur-containing antioxidants and phosphite-type antioxidants.

[0072] Mono-phenol based antioxidants include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, etc. Bisphenol type antioxidants include 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 3,9-bis(1,1-dimethyl-2-R-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxyethyl}2,4,9,10-tetraoxaspiro-5,5-undecane, etc. Polymerized phenol type antioxidants include 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-triethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, methyl tetramethylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, bis{(3,3'-bis-4'-hydroxy-3'-tert-butylphenyl)butyric acid glucoside, 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)trione and triphenol (vitamin E).

[0073] Sulfur-containing antioxidants include dilauryl thiodipropionate, dimyristyl thiodipropionate and distearyl thiodipropionate.

[0074] Phosphite type antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl-tricosyl) phosphite, cyclic neopentanetetrayl bis(octadecyl) phosphite, tris(mono- and / or di)phenyl phosphite, dipentaerythritol diisodecyl diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-tert-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, cyclic pentanetetra(2,4-tert-butylphenyl) phosphite, cyclic neopentanetetra(2,4-tert-butylphenyl) phosphite, cyclic neopentanetetramethyl bis(2-di-tert-butylphenyl) phosphite and 2,2-methylenebis(4,6-tert-butyl) octyl phosphite.

[0075] In one or more embodiments, the phenol type and phosphite type antioxidants can be used alone or preferably in combination to increase thermal stability.

[0076] With respect to the polymer at 100 phr (parts per hundred rubber / resin), the amount of antioxidant to be added can be in the range of from a lower limit of 0.001 phr, 0.01 phr, 0.1 phr, 0.2 phr, 0.3 phr, 0.4 phr, 0.5 phr, 1 phr or 2 phr to an upper limit of 0.5 phr, 0.6 phr, 0.7 phr, 0.8 phr, 0.9 phr, 1 phr, 2 phr, 3 phr, 4 phr or 5 phr, where any lower limit can be combined with any suitable upper limit. In one or more embodiments, the antioxidant can be in the range of 0.01 phr to 0.5 phr.

[0077] Light stabilizer

[0078] When combined with UV absorbers, the use of light stabilizers (LS), especially hindered amine type (HALS), produces a significant synergistic effect. Other typical LS compounds may play the same role as HALS, but many of them produce color in polymer compounds, so they are not suitable for use in solar cell encapsulation materials. Hindered amine light stabilizers are usually secondary amines, tertiary amines, acetylated amines, N-alkoxy-substituted amines, hydroxy-substituted amines or other substituted cyclic amines with a considerable amount of steric hindrance. Specifically, it includes, for example, the following molecules: dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine condensate, poly(6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)iminohexamethylene{{2,2,6,6-tetramethyl-4-piperidylimino), N,N'-bis(3-aminopropyl)ethylenediamine-2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-6-chloro-1,3,5-triazine condensate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) 2-(3,5-ditert-butyl-4-hydroxybenzyl)-2-n-butylmalonate (bis(1.2.2.6,6-pentamethyl-4-piperidyl) 2-(3,5-di-tert-4-hydroxybenzyl)-2-n-butylmalonate), C4-(methoxyphenyl)-methylene-, bis(1,2,6,6,6-pentamethyl-4-piperidyl) ester, polymethylpropyl-3-oxo-4-(2,2,6,6-tetramethyl) piperidyl siloxane, 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)-2,5-pyrrolidinedione, 1,3,5-triazine-2,4,6-triamine, N,N’-1,2-ethanediylbis 4,6-bis butyl(1,2,2,6,6-pentamethyl-4-piperidiny)amino-1,3,5-triazine-2-yl)imino-3,1propanediyl)-bisN’,N’-dibutyl-N’,N’-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-(N,N’-1,2-ethanediylbis 4,6-bis butyl(1,2,2,6,6-pentamethyl-4-piperidiny)amino-1,3,5-triazine-2-yl)imino-3,1propanediyl)-bisN’,N’-dibutyl-N’,N’-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-)(Chimassorb 119, CAS Reg. No. 106990-43-6); N,N’-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexane diamine, a polymer of 2,4,6-trichloro-1,3,5-triazine and 2,4,4-trimethyl-1,2-pentamine (Chimassorb 944, ACS Reg. No. 70624-18-9); and a polymer of N,N’-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexane diamine with 2,4,6-trichloro-1,3,5-triazine and tetrahydro-1,4-oxazine.

[0079] With respect to 100 phr of the polymer, the amount of the light stabilizer can be in the range of from a lower limit of 0.001 phr, 0.01 phr or 0.1 phr to an upper limit of 0.2 phr, 0.3 phr, 0.4 phr or 0.5 phr, where any lower limit can be used in combination with any suitable upper limit. In one or more embodiments, the light stabilizer can be in the range of 0.01 phr to 0.3 phr.

[0080] UV absorber

[0081] Any known UV absorber can be used in the present disclosure. Preferred general classes of UV absorbers are benzophenones, benzotriazoles, triazines, salicylates, hydroxybenzophenones, hydroxyphenyltriazines, esters of substituted and unsubstituted benzoic acids, etc., and mixtures thereof.

[0082] Specific benzophenone UV absorbers include, for example, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2-carboxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2-hydroxy-4-n-octadecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-5-chlorobenzophenone, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, and 2,2',4,4'-tetrahydroxybenzophenone.

[0083] Benzotriazole UV absorbers include hydroxyphenyl-substituted benzotriazole compounds such as 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy 5-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-3,5-dimethylphenyl)benzotriazole, 2-(2-methyl-4-hydroxyphenyl)benzotriazole, 2-(2-hydroxy-3-methyl-5-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-3,5-ditert-amylphenyl)benzotriazole, and 2-(2-hydroxy-3,5-ditert-butylphenyl)benzotriazole.

[0084] Triazine UV absorbers include 2-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-(octyloxy)phenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-(hexyloxy)phenol, etc. Salicylate-type UV absorbers include phenyl salicylate and p-octylphenyl salicylate.

[0085] Relative to 100 phr (parts per hundred rubber / resin) of the polymer, the amount of the UV absorber can be in the range of from a lower limit of 0.001 phr, 0.01 phr, 0.1 phr, 0.2 phr, 0.3 phr, 0.4 phr or 0.5 phr to an upper limit of 0.5 phr, 1.0 phr, 2.0 phr, 3.0 phr, 4.0 phr or 5.0 phr, wherein any lower limit can be used in combination with any suitable upper limit. In one or more embodiments, the UV absorber can be in the range of 0.01 phr to 0.5 phr.

[0086] Adhesion promoter

[0087] The most commonly used adhesion promoters are silane coupling agents, which are effective in improving the adhesion strength between the encapsulant material and the protective materials (front sheet, back sheet, and other materials made of glass or polymer) as well as the solar cell components (such as photovoltaic devices, metal grids, etc.). Compounds containing unsaturated groups (such as vinyl), acryloxy or methacryloxy groups, amino groups, epoxy groups, etc. and additionally having hydrolyzable groups (such as alkoxy groups) are viable molecules for the coupling agent.

[0088] Some specific molecules suitable for the above categories are γ-chloropropylmethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-vinylbenzylpropyltrimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltrichlorosilane, γ-mercaptopropylmethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-(3-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(3-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, etc., and the last two are the best choices in this application because they have good adhesion and hardly cause color problems (such as yellowing) during grafting / reaction.

[0089] With respect to 100 phr of the polymer, the amount of the silane coupling agent can be in the range of from a lower limit of 0.01 phr, 0.05 phr, 0.1 phr, 0.5 phr or 1 phr to an upper limit of 1 phr, 2 phr, 3 phr, 4 phr or 5 phr, wherein any lower limit can be used in combination with any suitable upper limit. In one or more embodiments, the silane coupling agent can be in the range of 0.1 phr to 3 phr.

[0090] Heat stabilizer

[0091] The heat stabilizer can be used as an optional additive in the solar cell encapsulation material to protect the polymer especially during processing (especially during the curing stage). Any conventional heat stabilizer can be used, including but not limited to: phenolic antioxidants, alkylated monophenols, alkylthiomethylphenols, hydroquinones, alkylated hydroquinones, tocopherols, hydroxylated thiodiphenyl ethers, alkylidene bisphenols, O-benzyl compounds, N-benzyl compounds and S-benzyl compounds, hydroxybenzylated malonic acid esters, aromatic hydroxybenzyl compounds, triazine compounds, amine antioxidants, arylamines, diarylamines, polyarylamines, acylaminophenols, oxamides, metal deactivators, phosphites, phosphonites, benzylphosphonates, ascorbic acid (vitamin C), peroxide deactivators, hydroxylamines, nitrones, thiosynergists, benzofuranones, indolinones and mixtures thereof. Its use is optional and in some cases not preferred (especially if it severely inhibits crosslinking).

[0092] With respect to 100 phr of the polymer, the heat stabilizer can be in the range of from a lower limit of 0.001 phr, 0.01 phr, 0.1 phr or 0.2 phr to an upper limit of 1 phr, 2 phr, 3 phr, 4 phr or 5 phr, wherein any lower limit can be used in combination with any suitable upper limit. In one or more embodiments, the heat stabilizer can be in the range of 0.01 phr to 1 phr.

[0093] Plasticizer

[0094] The polymer composition according to the present disclosure may comprise one or more plasticizers to adjust the physical properties and processing performance of the composition. In some embodiments, the plasticizer according to the present disclosure may include one or more of the following: bis(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), di(n-butyl) phthalate (DNBP), butyl benzyl phthalate (BZP), diisodecyl phthalate (DIDP), di-n-octyl phthalate (DOP or DNOP), diisooctyl phthalate (DIOP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP), di-n-hexyl phthalate, trimethyl trimellitate (TMTM), tris(2-ethylhexyl) trimellitate (TEHTM-MG), tris(n-octyl, n-decyl) trimellitate, tris(heptyl, nonyl) trimellitate, n-octyl trimellitate, bis(2-ethylhexyl) adipate (DEHA), dimethyl adipate (DMD), monomethyl adipate (MMAD), dioctyl adipate (DOA), dibutyl sebacate (DBS), polyester of adipic acid (such as VIERNOL), dibutyl maleate (DBM), diisobutyl maleate (DIBM), benzoate, epoxidized soybean oil and its derivatives, n-ethyl toluenesulfonamide, n-(2-hydroxypropyl) benzenesulfonamide, n-(n-butyl) benzenesulfonamide, tricresyl phosphate (TCP), tributyl phosphate (TBP), ethylene glycol / polyester, triethylene glycol dihexanoate (3gh), tetraethylene glycol diheptanoate, polybutene, acetylated glycerol monoester; alkyl citrate, triethyl citrate (TEC), acetyltriethyl citrate, tributyl citrate, acetyltributyl citrate, trioctyl citrate, acetyltrioctyl citrate, trihexyl citrate, acetyltrihexyl citrate, tributyl butyryl citrate, o-tributyl butyryl citrate, trimethyl citrate, phenyl alkylsulfonate, diisononyl 2-cyclohexanedicarboxylate, nitroglycerin, trinitroglycerin, dinitrotoluene, trimethylolethane trinitrate, diethylene glycol dinitrate, triethylene glycol dinitrate, bis(2,2-dinitropropyl) formal, bis(2,2-dinitropropyl) formal, 2,2,2-trinitroethyl 2-nitroxyethyl ether, mineral oil, vegetable oil or bio-based oil, and other plasticizers and polymeric plasticizers. In certain embodiments, one of the one or more plasticizers may be mineral oil.

[0095] The polymer composition according to the present invention may optionally include plasticizer in an amount ranging from 0 phr to 20 phr. The plasticizer may be present in an amount ranging from a lower limit of one of 0 phr, 1.0 phr, 2.0 phr, 5.0 phr, 8.0 phr, and 10.0 phr to an upper limit of one of 12 phr, 15 phr, 18 phr, 19 phr, and 20 phr, wherein any lower limit may be combined with any suitable upper limit.

[0096] Film

[0097] In one or more embodiments, a film comprising the above polymer composition and specifically including a copolymer or terpolymer can be prepared. The film can be prepared by cast film extrusion, blown film extrusion, calendering, or any method suitable for preparing a film. The film according to the present disclosure can be suitable for use as a solar cell encapsulant material, a tie layer, and a glass laminate. The film can be non-crosslinked or crosslinked.

[0098] The film according to one or more embodiments can comprise a polymer (copolymer or terpolymer) having a total comonomer content (branched vinyl ester and optionally vinyl acetate) in the range from a lower limit selected from one of 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or 30 wt% to an upper limit selected from 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, or 60 wt%, wherein any lower limit can be combined with any suitable upper limit.

[0099] The film according to one or more embodiments can comprise a polymer (copolymer or terpolymer) having a density ranging from a lower limit selected from one of 0.8 g / cm 3 、0.9 g / cm 3 、0.905 g / cm 3 、0.91 g / cm 3 、0.915 g / cm 3 、0.92 g / cm 3 、0.925 g / cm 3 、0.93 g / cm 3 to an upper limit selected from one of 0.95 g / cm 3 、0.955 g / cm 3 、0.96 g / cm 3 、0.965 g / cm 3 、0.97 g / cm 3 、0.98 g / cm 3 、0.99 g / cm 3 、1.0 g / cm 3 、1.1 g / cm 3 、1.2 g / cm 3 or 1.3 g / cm 3 wherein any lower limit can be combined with any suitable upper limit.

[0100] The film according to one or more embodiments may comprise a polymer (copolymer or terpolymer) having a melt index (I2) in the range of from a lower limit of 0.1 g / 10 min, 0.5 g / 10 min, 1 g / 10 min, 2 g / 10 min, 5 g / 10 min, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 30 g / 10 min, 40 g / 10 min or 50 g / 10 min to an upper limit of 50 g / 10 min, 60 g / 10 min, 70 g / 10 min, 80 g / 10 min, 90 g / 10 min or 100 g / 10 min as measured according to ASTM D1238 (at 190 °C and a load of 2.16 kg), wherein any lower limit can be combined with any suitable upper limit.

[0101] The film according to one or more embodiments may have a thickness in the range of from a lower limit of 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 10 μm, 15 μm, 20 μm, 30 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm or 500 μm to an upper limit of 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1000 μm, wherein any lower limit can be combined with any suitable upper limit.

[0102] Solar cell encapsulation material

[0103] As described above, the film of the present disclosure can be used as a solar cell encapsulation material, wherein the film can be applied to a solar or photovoltaic (PV) cell as a substrate.

[0104] The PV cells can be crystalline, semi-crystalline or amorphous and are typically encapsulated in multiple protective layers including a front cover, an encapsulation film and a backsheet, such as a five-layer laminate of front cover / encapsulation film / PV cell and electrical wiring / encapsulation film / backsheet. In particular, the polymer composition and the film containing the polymer composition of the present disclosure can be used as an encapsulation material.

[0105] In addition to the copolymers or terpolymers described in this specification, the film used as a solar cell encapsulation material may include one or more of the following: a crosslinking agent in an amount of 0.01 phr to 10 phr; a crosslinking aid in an amount of 0.01 phr to 5 phr; a primary antioxidant in an amount of 0.01 phr to 5 phr; a secondary antioxidant in an amount of 0.01 phr to 5 phr; a light stabilizer in an amount of 0.01 phr to 5 phr; a UV absorber in an amount of 0.01 phr to 5 phr; an adhesion promoter in an amount of 0.01 phr to 5 phr; or optionally, at least one additive selected from the group consisting of a heat stabilizer, a plasticizer, a rubber, an elastomer, a filler and combinations thereof.

[0106] In one or more embodiments, a film suitable for use as a solar cell encapsulant material may comprise a polymer having a density ranging from a lower limit selected from one of 0.92 g / cm 3 , 0.925 g / cm 3 , 0.93 g / cm 3 , 0.935 g / cm 3 or 0.94 g / cm 3 to an upper limit selected from one of 0.95 g / cm 3 , 0.955 g / cm 3 , 0.96 g / cm 3 , 0.965 g / cm 3 or 0.97 g / cm 3 , wherein any lower limit may be combined with any suitable upper limit. In one or more embodiments, the polymer may have a density ranging from 0.93 g / cm 3 to 0.96 g / cm 3 .

[0107] In one or more embodiments, a film suitable for use as a solar cell encapsulant material may comprise a polymer having a melt index (I2) measured according to ASTM D1238 (at 190 °C and a load of 2.16 kg) ranging from a lower limit of 1 g / 10 min, 2 g / 10 min, 5 g / 10 min, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 40 g / 10 min or 50 g / 10 min to an upper limit of 50 g / 10 min, 60 g / 10 min, 70 g / 10 min, 80 g / 10 min, 90 g / 10 min, 100 g / 10 min, 150 g / 10 min or 200 g / 10 min, wherein any lower limit may be combined with any suitable upper limit. In one or more embodiments, the polymer may have a melt index (I2) ranging from 2 g / 10 min to 200 g / 10 min, or even from 5 g / 10 min to 50 g / 10 min.

[0108] In one or more embodiments, a film suitable for use as a solar cell encapsulant material may comprise a polymer having a melting temperature measured according to ASTM D3418 ranging from a lower limit of 30 °C, 40 °C, 50 °C or 60 °C to an upper limit of 60 °C, 70 °C, 80 °C, 90 °C or 100 °C, wherein any lower limit may be combined with any suitable upper limit. In one or more embodiments, the polymer may have a melting temperature of less than 90 °C or a range of 60 °C to 80 °C.

[0109] In one or more embodiments, a film suitable as a solar cell encapsulation material may comprise a polymer having a volume resistivity greater than 1x10 14 Ohm·cm or greater than 1x10 15 Ohm·cm, as measured according to ASTM D257.

[0110] In one or more embodiments, a film suitable as a solar cell encapsulation material may comprise a polymer having a Shore A hardness less than 90 Shore A or less than 80 Shore A, as measured according to ASTM D2240.

[0111] In one or more embodiments, a film suitable as a solar cell encapsulation material may comprise a polymer having a Vicat softening point less than 75 °C, or less than 70 °C, or less than 65 °C, or less than 60 °C, or less than 55 °C, or less than 50 °C, or less than 45 °C, or less than 42 °C, as measured according to ASTM D1525.

[0112] In one or more embodiments, a film suitable as a solar cell encapsulation material may comprise a polymer having a contact angle greater than 70°, or greater than 75°, or greater than 80°, or greater than 85°, or greater than 90°, as measured according to ASTM D5946.

[0113] In one or more embodiments, a film suitable as a solar cell encapsulation material may have an optical transmittance greater than 80%, or greater than 85%, or greater than 90%, or greater than 91%, or greater than 92%, or greater than 93%, or greater than 94%, or greater than 95%, as measured according to ASTM D1003.

[0114] In one or more embodiments, a film suitable as a solar cell encapsulation material may have a haze less than 15%, or less than 10%, or less than 9%, or less than 8%, or less than 7%, or less than 6%, or less than 5%.

[0115] In one or more embodiments, a film suitable as a solar cell encapsulation material may have a water vapor transmission coefficient less than 25000 μm·g / m 2 ·day, less than 24000 μm·g / m 2 ·day, less than 23000 μm·g / m 2 ·day, less than 22000 μm·g / m 2 ·day, less than 21000 μm·g / m 2 ·day or less than 20000 μm·g / m 2 ·day, as measured according to ASTM F1249.

[0116] In one or more embodiments, the film suitable for use as a solar cell encapsulation material may have a breaking stress measured according to ASTM D638 of at least 5 MPa, at least 6 MPa, at least 7 MPa, at least 8 MPa, at least 9 MPa, or at least 10 MPa.

[0117] In one or more embodiments, the film suitable for use as a solar cell encapsulation material may have a breaking strain measured according to ASTM D638 of at least 500%, at least 600%, at least 700%, at least 800%, at least 900%, or at least 1000%.

[0118] In one or more embodiments, the film suitable for use as a solar cell encapsulation material is crosslinked and may have a UV cut-off wavelength of 380 nm or even 360 nm measured by UV / Vis or UV / Vis / NIR spectroscopy.

[0119] In one or more embodiments, the film suitable for use as a solar cell encapsulation material may exhibit a gloss of at least 70%, at least 73%, at least 77%, or at least 80% measured according to ASTM D2457 at 45°.

[0120] In one or more embodiments, the film suitable for use as a solar cell encapsulation material may exhibit a gloss of at least 80%, at least 85%, at least 90%, or at least 95% measured according to ASTM D2457 at 60°.

[0121] In one or more embodiments, the film suitable for use as a solar cell encapsulation material may comprise a polymer composition that exhibits a glass transition temperature of less than -15 °C, less than -17 °C, less than -19 °C, less than -21 °C, less than -23 °C, or less than -25 °C measured via tan δ.

[0122] In one or more embodiments, the film suitable for use as a solar cell encapsulation material may comprise a polymer composition that exhibits a glass transition temperature of less than -25 °C, less than -27 °C, less than -29 °C, less than -31 °C, less than -33 °C, or less than -35 °C measured via loss modulus.

[0123] Film preparation method

[0124] The embodiments disclosed in this specification may relate to a method of preparing a film comprising a polymer composition according to the present disclosure. The method may include preparing a polymer composition by blending a polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate according to the embodiments described in this specification, and optionally one or more of the following: peroxide, crosslinking aid, primary antioxidant, secondary antioxidant, light stabilizer, UV absorber, adhesion promoter, heat stabilizer, plasticizer, rubber / elastomer, filler, and combinations thereof.

[0125] The blending may be carried out according to any suitable method, and the blending may include using a twin-screw extruder, a single-screw extruder, a kneader, a Banbury mixer, a mixing roll, or a cast film extruder.

[0126] Then, the prepared polymer composition may be used to prepare a film comprising the polymer composition. The film may be produced via cast film extrusion, blown film extrusion, calendering, or any other suitable method.

[0127] Article

[0128] The embodiments disclosed in this specification may relate to an article comprising at least one film disclosed in this specification. The article may include a substrate to which the film is applied. The article may include one or more substrates. For example, the article may be an encapsulated solar cell.

[0129] Method of preparing an article

[0130] The embodiments disclosed in this specification may relate to a method of preparing an article comprising a film according to the embodiments disclosed in this specification. The method may include applying the film to a substrate, wherein the applying includes vacuum laminating the film according to the present disclosure to the substrate, wherein the film encapsulates and / or adheres a photovoltaic device to the substrate. Encapsulation of the photovoltaic device may include crosslinking the film according to the present disclosure by exposure to a vacuum lamination process.

[0131] The vacuum lamination process may be carried out in a pressure range from a lower limit of 5 kPa, 10 kPa, 20 kPa, 30 kPa, 40 kPa, or 50 kPa to an upper limit of 100 kPa, 150 kPa, or 200 kPa, wherein any lower limit may be combined with any suitable upper limit.

[0132] The vacuum lamination process can be carried out within a temperature range from a lower limit of 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C or 190°C to an upper limit of 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C or 320°C, where any lower limit can be combined with any suitable upper limit.

[0133] The vacuum lamination process can be carried out within a time range from a lower limit of 0.5 min, 1 min, 2 min, 3 min, 4 min, 5 min, 10 min, 20 min, 30 min to an upper limit of 60 min, 75 min, 90 min or 2 hours, where any lower limit can be combined with any suitable upper limit.

[0134] Materials, Experimental Methods and Characterization

[0135] Materials

[0136] Compositions based on ethylene, vinyl acetate and vinyl neodecanoate (VeoVA TM 10) were tested. The terpolymer samples DV001A and DV001B were produced in a high-pressure industrial plant commonly used for the production of EVA copolymers. The general reactor conditions for the production of the terpolymers are shown in Table 1.

[0137] Table 1

[0138]

[0139] In 13 Evidence of the inclusion of branched vinyl esters and vinyl acetate was observed in both the carbonyl region (170 - 180 ppm) and the alkyl region (0 - 50 ppm) of the 13C NMR spectrum (TCE-D2, 393.1 K, 125 MHz). 1 The 1H NMR spectrum (TCE-D2, 393.2 K, 500 MHz) showed peaks for vinyl acetate and branched vinyl esters (4.7 - 5.2 ppm) and ethylene (1.2 - 1.5 ppm), as well as additional peaks in the alkyl region (0.5 - 1.5 ppm) indicating long alkyl chains on the branched vinyl ester monomers. The relative intensities of the peaks found in the 1 1H NMR and 13 13C NMR spectra were used to calculate the monomer content of branched vinyl esters and vinyl acetate in the copolymer / terpolymer.

[0140] Neat Polymer Characterization

[0141] As described above, by1 H NMR and 13 C NMR measurements were performed on the VA and VeoVa TM content of 10. The melting and crystallization behaviors of the samples were studied by DSC. Experiments were carried out in a nitrogen atmosphere in a TA Instruments DSC Discovery–DSC 2500 according to ASTM D3418. The samples were cooled from 200 °C to -20 °C and then heated to 200 °C at a rate of 10 °C / min.

[0142] The density was measured according to ASTM D792, the Vicat softening point (10 N) was measured according to ASTM D1525, the hardness (Shore A) was measured according to ASTM D2240, the contact angle was measured according to ASTM D5946, and the volume resistivity was measured according to ASTM D257. The specimens used to measure density, Vicat, hardness, contact angle, and volume resistivity were prepared by compression molding according to ASTM D4703 and conditioned at 23 °C, 50% RH for at least 24 hours. The melt flow index was evaluated at 190 °C, 2.16 kg according to ASTM D1239.

[0143] Extrusion of pure composite films

[0144] The cast films of the above polymers (pure) and the compounds to be described in Example 3 were prepared in a cast film extruder Leonard OCS ME-20 / 2800-V3 using a flat die and a chilled pulling roll. Before extrusion, the die was cleaned using a scraper and brass wire wool. The temperature profile and the melting temperature were limited to 140 °C (for the formulation, below 120 °C) in order to evaluate the processability and aesthetics of the film under these conditions. Due to the strong adhesion of the EVA film to the extrusion roll, it was covered with kraft paper in advance and cooled to approximately 9 °C.

[0145] Characterization of the films

[0146] The pure polymer films were tested for relevant properties (optical, mechanical, and barrier) and are presented in the table below. The water vapor transmission rate and the degree of crosslinking (described in Example 4) expressed by the gel content in boiling xylene can also be measured in the crosslinked films.

[0147] Optical properties (clarity, haze, and transmittance) were determined according to ASTM D1003, gloss (45° and 60°) was determined according to ASTM D2457, water vapor transmission rate was determined according to ASTM F1249 (37.8 °C, 100% RH, 1 atm), and tensile testing was performed according to ASTM D882 (crosshead speed of 500 mm / min, using an optical extensometer, where stress and strain at yield and break, and secant modulus (1%)) were reported.

[0148] Compression-molded samples - crosslinking protocol

[0149] Samples were crosslinked by compression molding according to ASTM D4703 (standard heating cycle, then held at 150 °C for 1 h under standard pressure, then standard cooling cycle).

[0150] Characterization of crosslinked compression-molded samples

[0151] Crosslinked compression-molded samples were subjected to the following tests: tensile (stress and strain at break, and tensile modulus - measured at 500 mm / min using an optical extensometer according to ASTM D638), Shore A hardness (according to ASTM D2240), DSC (tested from -20 °C to 200 °C at a heating rate of 10 °C / min according to ASTM D3418), gel content (in-house method based on ASTM D2765 - sieve #120, extraction with boiling xylene for 8 h, then dried in an oven at 100 - 150 °C until constant weight (about 1 h)), and DMA (tensile mode, from -150 °C to 150 °C, heating rate of 3 °C / min, deformation amplitude of 15 μm).

[0152] The glass transition temperature (T g ) of the neat and crosslinked samples was determined by the maximum of the Tanδ peak measured on the sample during DMA measurement using a TA800DMA instrument in tensile mode. The film (about 0.5 mm) was compression-molded at 150 °C, cooled to -150 °C, and its viscoelastic response was evaluated by temperature scanning at a rate of 3 °C / min, while a preload force of 0.01 N was applied at a frequency of 1 Hz and an amplitude of 15 μm. Storage modulus, loss modulus, and tanδ (the ratio of storage modulus to loss modulus) were recorded as a function of temperature.

[0153] Examples

[0154] Example 1: Characterization of neat polymers - The basic properties of the above-mentioned terpolymers (labeled DV001A, DV001B) and EVA benchmarks (Braskem S.A. grade HM728 and SK Chemicals Co. grade EVATANE 3345PV) are shown in Table 2.

[0155] Table 2

[0156]

[0157]

[0158] *Data from the technical data sheet.

[0159] The volume resistivity was measured for compression-molded pure parts (2 mm thick) according to ASTM D257 in accordance with ASTM D4703. The results are shown in Table 3.

[0160] Table 3

[0161]

[0162] Compared to HM728, the volume resistivity of the terpolymers shows very close values, with the average of DV001B being slightly higher. The resistivity of the above three grades is significantly higher than that of EVATANE 3345PV. A high volume resistivity value is ideal for this application because current leakage or dielectric breakdown is highly undesirable as it reduces module efficiency or even destroys its function.

[0163] Example 2: A pure film was prepared according to the above film extrusion protocol. The film was collected and rolled up with kraft paper to avoid clogging. The extrusion parameters are as follows:

[0164] Table 4

[0165]

[0166] The film was characterized according to the above method. Overall, similar optical properties were observed; compared to HM728, the terpolymers have slightly higher clarity and slightly lower haze, as shown in Tables 5 and 6. Evatane shows better optical properties. However, since a higher MFR also promotes extrusion, this seriously affects the optical properties. A lower water vapor transmission coefficient was observed for the terpolymers, especially for DV001B containing the most VeoVa TM 10 monomers, as shown in Table 7.

[0167] Table 5

[0168]

[0169] Table 6

[0170]

[0171] Table 7

[0172]

[0173]

[0174] Example 3: All the materials described above were compounded in a twin-screw extruder ZSK-26 (Coperion) according to the following formulation, where the wire was cooled in a water bath and then pelletized. Sample preparation included micronizing about 20% wt of EVA (low-temperature conditions - liquid nitrogen) in order to better absorb liquid peroxide, and then dry blending all components in a plastic bag, as shown in Table 8. Finally, they were added to the main feeder of the extruder under the specified extrusion conditions, as shown in Table 9.

[0175] Table 8

[0176]

[0177] Table 9

[0178]

[0179]

[0180] The samples were crosslinked and characterized according to the above method. Although the thickness was different compared to the compression-molded plate, the breaking stress of the crosslinked material increased significantly compared to the pure polymer.

[0181] Table 10

[0182]

[0183] For the pure and crosslinked films prepared according to the above method, the glass transition temperature was obtained. The results are as follows:

[0184] Table 11

[0185]

[0186]

[0187] It can be seen that the Tg of the terpolymers are very similar to each other and are comparable to the measured values of 33 wt% VA EVA (EVATANE 3345PV) both in the pure state (slightly higher by tanδ and lower by loss modulus) and when crosslinked (lower by tanδ and loss modulus). Additionally, the Tg of both terpolymers is lower than that of EVA with 28 wt% VA (HM728). This indicates that the terpolymers studied exhibit good low-temperature flexibility and may even be superior to commercial products.

[0188] In the neat state, EVATANE has a slightly lower Tg (by tanδ) and a slightly higher peak, which means higher segmental mobility (since it is a polymer with lower crystallinity), followed by the terpolymers (which are very similar to each other), and finally HM728, with a slightly higher Tg and a lower tanδ peak. For the crosslinked polymers, a similar trend was observed; however, the crosslinked terpolymers showed a behavior closer to that of EVATANE 3345PV.

[0189] The gel content extracted by boiling xylene was determined according to the aforementioned method. The results are shown below:

[0190] Table 12

[0191]

[0192] According to the aforementioned method, the thermal properties of the neat and crosslinked samples were determined by DSC. The crosslinked samples were cut from the tensile test dog bones, and the neat samples were molded into films. It can be seen that the trend of the crosslinked samples is the same as that of the neat polymers. Compared with HM728, the Tm2, Tc, and ΔHm (enthalpy of fusion) of DV001A are slightly lower, but the terpolymer with 5 wt% VeoVA TM 10 has a significantly lower Tc, as shown in Table 13.

[0193] Table 13

[0194]

[0195] The DSC data generally also follow the trend observed for the neat polymers. Compared with other materials, the Tm and enthalpy of fusion of EVATANE are much lower. All materials show lower Tm, Tc, and ΔH in the crosslinked case, which may be due to the reduced chain mobility imposed by crosslinking, resulting in lower crystallinity and reduced lamellar thickness.

[0196] The Tm, Tc, and ΔHm of DV001A are lower than those of HM728, which matches the results of the optical properties, hardness, modulus, tensile, and Vicat. DV001B shows basically the same thermal behavior as HM728, but shows excellent optical properties (only slightly better), as shown in Example 4.

[0197] Example 4: Using the same method / considerations as for the neat film, films of the extrusion formulation were produced via cast film extrusion (except that kraft paper was not used to cover the cooling roll). The extrusion parameters are as follows:

[0198] Table 14

[0199]

[0200] Using The sheet is cured by compression molding the film of the sample to avoid adhesion to the substrate. No significant pressure (3.5 tons) is applied to avoid too much change in the sheet thickness. The molding process is carried out at 160 °C for 60 minutes. After molding, the sample is cooled in a table (concrete) with no specific cooling rate and carefully taken out the sheet to avoid damaging the sheet.

[0201] As described above, the water vapor transmission rate and gel content of the test samples are measured. The water vapor transmission rate is determined according to ASTM F1249 under the following conditions: 37.8 °C, 1 atm, relative humidity of 100%, and the method uncertainty is 5%, as shown in Table 15.

[0202] Table 15

[0203]

[0204] According to the aforementioned method, the gel content of the film is determined by extraction with boiling xylene. The results are as follows:

[0205] Table 16

[0206]

[0207] Example 5 - Aging Tests (UV Degradation and Damp Heat Tests)

[0208] The film of the above formula and the standard commercial Sentryglas (Kuraray) are laminated between glass substrates.

[0209] The materials are placed in a laminator (radiation solar panel laminator YDS - 0707, Yudian Solar), heated to 100 °C under vacuum (-90 kPa) for 30 minutes to melt the EVA, spread it out and fill the space of the laminate. Applying vacuum helps to remove air and final volatiles in the film and prevent the formation of bubbles - applying vacuum for 60 minutes.

[0210] After that, the temperature is raised to 120 °C for another 30 minutes (still under vacuum) to more effectively eliminate the residual stress in the film and avoid shrinkage during curing and cooling. For the curing cycle, then the temperature is raised to 160 °C, and a pressure of 85 kPa is applied to the laminate with a diaphragm for 1 hour. Then, the sample is taken out of the laminator and left at room temperature to cool. Figure 1 and Figure 2 the entire lamination cycle diagram and schematic diagram shown.

[0211] The obtained glass - laminated sample is a 5x5 cm square, and the image of the sample after the lamination process is as Figure 3 shown.

[0212] In the glass laminate samples, the initial optical properties (UV / Vis spectra) were measured. Before placing the samples in a UV lamp or UV chamber, transparency measurements were carried out at different wavelengths (Shimadzu UV2600) in the wavelength range from 300 nm to 1000 nm in order to evaluate the initial optical transmittance of the film. The initial spectra of the samples are as Figure 4 shown.

[0213] In addition, an aging test was also carried out, in which the samples were evaluated regularly (every 3 - 4 days) by UV-Vis spectroscopy in order to track and compare the degradation kinetics. UV aging was carried out under continuous irradiation of 1000 W / m 2 . (Lamp: Lumixo S plasma lamp - Lumartix). Due to the heat emitted by the lamp, the samples were at a temperature of approximately 65 °C. After 2000 hours, the temperature was raised to 85 °C using a hot plate to accelerate the degradation.

[0214] Humid heat test - Accelerated degradation was carried out in an environmental chamber (Blue M, CEO932 - 4) with high temperature and high humidity content (65 °C, 85% RH) and exposure to UV radiation (halogen lamp). The spectra of the UV aging and humid heat climate chambers are as Figure 5 shown.

[0215] For the data generated in both tests (UV degradation and humid heat), the main calculated parameter is the spectral area obtained by numerical integration using the trapezoidal rule and with the aid of Microsoft Excel to quantify the overall transmittance of the samples at all the studied wavelengths. The integral of each measurement was plotted against time to understand the behavior of the samples over the entire test period (approximately 3000 hours).

[0216] In the UV degradation test, indicators such as the initial transmittance and the slope of the transmittance over time were calculated and compared, and these indicators may be related to the degradation rate of the material.

[0217] UV degradation test - Results

[0218] In Figure 6 , the transmittance of all samples under UV irradiation is shown. Compared with EVA, it can be observed that the slopes of the terpolymers (DV001A and DV001B) are smaller. On the other hand, Sentryglas shows a positive slope and the transmittance increases over time. The different behavior of Sentryglass under UV irradiation can be explained by the fact that it is a different material (ionomer). Therefore, Figure 6 the direct comparison in

[0219] containing VeoVa TMThe terpolymers of 10 exhibit a smaller slope (angular coefficient) - the transmittance decreases at a slower rate over time - which may be related to a slower degradation rate. This is consistent with the comparison results in the literature for copolymers based on vinyl acetate and larger branched vinyl esters. The comparison between the transmittances of the samples is as Figures 7 to 9 shown.

[0220] The indices calculated from the numerical integration data (angular coefficient (m), linear coefficient (b), and initial transmittance - b0) are as Figure 10 , Figure 11 and Figure 12 shown.

[0221] In terms of the initial transmittance, both the measured value and the linearly fitted value of EVATANE are the highest, which is consistent with the previous findings (film transmittance) and the lower crystallinity theory (due to the relatively high molar percentage of comonomers in the ethylene copolymer), resulting in a higher transmittance. However, the values of DV001A and DV001B are comparable to those of HM728. The transmittances of all terpolymers and EVA are higher than that of Sentryglas. Finally, the comparison trend between the fitted linear coefficient and the measured value is the same, and the actual values are very close, except for DV001A, which has a slightly larger difference.

[0222] Damp heat test - results

[0223] The evaluation of the damp heat test performance was carried out considering the following parameters: 1) the initial transmittance (t = 0) - the transmittance before exposure to the environmental chamber, 2) the plateau region observed after the initial sharp drop ((linear coefficient in the linear fit), and the difference (Delta) between the initial transmittance (t0) and the plateau transmittance. The plateau value was calculated by linear fitting using Microsoft Excel, where the angular coefficient was adjusted to be as close to zero as possible in the fit. Three parameters were plotted and compared, as Figures 13 to 1 shown in Figure 9.

[0224] Since Sentryglas is a different material (ionomer), it exhibits different behavior from other laminated samples when considering the initial transmittance. However, considering their respective plateau regions, Sentryglas shows very comparable transmittances to all EVA and terpolymers.

[0225] In terms of the plateau value, it can be seen that the value of DV001A is the largest, while the value of EVATANE is lower (followed by HM728). Although the difference is not necessarily large (comparing DV001A and EVATANE, the difference is 4.9%). The response of DV001B is a value very close to the response of DV001A (0.32% lower than DV001A).

[0226] The difference between the initial transmittance and the plateau transmittance indicates the degree of influence of the test on the optical properties of the film. The values of DV001A and the two types of EVA are the highest (close to 9.5%). The difference between the initial transmittance and the plateau transmittance of DV001B is approximately 7.3%.

[0227] Therefore, it is obvious that the films of the present invention (especially the films containing DV001A) exhibit high plateau transmittance and have no significant differences in terms of test performance loss, indicating their suitability for this application and potential competitive advantages if compared with films containing traditional EVA.

[0228] Example 6: Adhesion test

[0229] The same protocol (annealing, crosslinking parameters) was used to prepare samples for glass adhesion testing. Glass substrates with dimensions of 2.5 cm x 10 cm x 4 mm, commercial backsheet materials (CPX1000 - crosslinked polyolefin-based backsheet), and extruded films with the aforementioned formulations were cut into appropriate sizes and laminated. Adhesion tests were conducted. As Figure 20 shown in the schematic diagram.

[0230] Adhesion test - A 90° peel test was performed on the aforementioned samples (glass / membrane / crosslinked polyolefin laminate) at a speed of 300 mm / min according to ASTM D3330 in a sample with a length of 10 cm (actually 9 cm plus EVA adhesive) and a width of 2.5 cm. Three tests were conducted according to the materials.

[0231] In terms of data analysis, the average values of force (N), work (N·mm), and energy (N / mm) were calculated, where the work and energy were obtained using numerical integration (trapezoidal rule) of the raw data of force versus displacement. The work and energy of all samples were compared, and the values from 0 to 85 mm were used to reduce the difference in the total test length.

[0232] On the other hand, for the average force, more specific regions in the graph were used, considering the initial region, the end region, and the sharp increase and decrease of the measured force in order to better represent the average value. These graphs are shown in Figure 21 and Figure 22 (the scales between the graphs are different), and the calculated numerical results are shown in Tables 17 to 19.

[0233] Table 17 - Average force of adhesion test

[0234]

[0235]

[0236] Table 18 - Average work of adhesion test

[0237]

[0238] Table 19 - Average Energy of Adhesion Test

[0239]

[0240] The performance of DV001A can be noted to be superior to all other grades - including EVATANE 3345PV - by all metrics. The lowest adhesion was found for HM728. The VA, VeoVa, and total comonomer content are not directly related to the adhesion strength, and no relationship was observed with the contact angle (which is related to surface energy) and MFR (which may be related to the ability to spread and effectively wet the substrate).

[0241] Although only a few exemplary embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications can be made in the exemplary embodiments without materially departing from the invention. Accordingly, all such modifications are intended to be included within the scope of the present disclosure as defined by the appended claims. In the claims, the functional limitation (means-plus-function clause) is intended to cover the structures described in the present disclosure as performing the recited function, which covers not only structural equivalents but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents because a nail uses a cylindrical surface to fasten wooden parts together while a screw uses a helical surface, in the context of fastening wooden parts, a nail and a screw can be equivalent structures. The applicant's express intent is not to invoke 35 U.S.C. § 112(f) to impose any limitation on any of the claims in this specification, except those claims that expressly use the phrase "means for" in conjunction with the associated function.

Claims

1. A film comprising a polymer composition, the polymer composition comprising: a polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, wherein the ethylene content ranges from 40 wt% to 99.9 wt%, and the melt index (I2) measured according to ASTM D1238 at 190 °C and a load of 2.16 kg is from 0.1 g / 10 min to 100 g / 10 min.

2. The membrane according to claim 1, wherein, The polymer composition further comprises one or more of the following: a crosslinking agent in an amount of 0.01 phr to 10 phr; a crosslinking aid in an amount of 0.01 phr to 5 phr; a primary antioxidant in an amount of 0.01 phr to 5 phr; a secondary antioxidant in an amount of 0.01 phr to 5 phr; a light stabilizer in an amount of 0.01 phr to 5 phr; a UV absorber in an amount of 0.01 phr to 5 phr; an adhesion promoter in an amount of 0.01 phr to 5 phr; or optionally, at least one additive selected from the group consisting of heat stabilizers, plasticizers, rubbers, elastomers, fillers, and combinations thereof.

3. The membrane according to claim 1 or 2, wherein, The one or more branched vinyl ester monomers have the general formula structure (II): wherein R 4 and R 5 have a total carbon number of 7.

4. The membrane according to any one of the above claims, wherein, The total comonomer content of the polymer ranges from 10 wt% to 60 wt%, preferably from 20 wt% to 50 wt%.

5. The membrane according to any one of the preceding claims, wherein, The density of the polymer measured according to ASTM D792 ranges from 0.8 g / cm 3 to 1.3 g / cm 3 , preferably from 0.93 g / cm 3 to 0.96 g / cm 3 .

6. The membrane according to any one of the above claims, wherein, The melt index (I2) of the polymer measured according to ASTM D1238 at 190 °C and a load of 2.16 kg ranges from 1 g / 10 min to 100 g / 10 min, preferably from 5 g / 10 min to 50 g / 10 min.

7. The membrane according to any one of the above claims, wherein, The polymer has one or more of the following properties: - a melt temperature measured according to ASTM D3418 of less than 90 °C, preferably from 60 °C to 80 °C; - The volume resistivity measured according to ASTM D257 is greater than 1x10 14 Ohm·cm, preferably greater than 1x10 15 Ohm·cm; - a Shore A hardness measured according to ASTM D2240 of less than 90, preferably less than 80; - a Vicat softening point measured according to ASTM D1525 of less than 50 °C; - a contact angle measured according to ASTM D5946 of greater than 80°; - an optical transmittance measured according to ASTM D1003 of greater than 85%, preferably greater than 93%; - a haze measured according to ASTM D1003 of less than 10%, preferably less than 8%; - The water vapor transmission coefficient measured according to ASTM F1249 is less than 22000 μm·g / m 2 ·day; - a fracture stress measured according to ASTM D638 of at least 5 MPa, preferably at least 9 MPa; - a fracture strain measured according to ASTM D638 of at least 500%, preferably at least 800%; - a UV cut-off wavelength of 380 nm, preferably 360 nm; - an optical clarity measured according to ASTM D1003 of greater than 80%, preferably greater than 89%; and - a glass transition temperature measured by DMA using a tensile fixture, tension ° / min, and measured by tanδ according to ASTM D4065 of less than -19 °C, and a glass transition temperature measured by loss modulus of less than -29 °C.

8. The membrane according to any one of the preceding claims, wherein The film is crosslinked.

9. The membrane according to any one of the preceding claims, wherein, The film exhibits a gloss of at least 77% measured according to ASTM D2457 at 45°.

10. The membrane according to any one of the above claims, wherein, The film exhibits at least 90% gloss measured according to ASTM D2457 at 60°.

11. A method of producing a film according to any one of the preceding claims, the method comprising: Blending the polymer composition, the polymer composition comprising: A polymer produced from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate; and Optionally: peroxide; crosslinking aid; primary antioxidant; secondary antioxidant; light stabilizer; UV absorber; adhesion promoter; heat stabilizer; plasticizer; rubber / elastomer; filler, and combinations thereof; Wherein the blending method comprises using a twin-screw extruder, a single-screw extruder, a kneader, a Banbury mixer, a mixing roll, or a cast film extruder; and Producing a film having a thickness in the range of 5 μm to 800 μm via cast film extrusion, blown film extrusion, or calendering.

12. The method according to claim 11, wherein, The film has a thickness range of 50 μm to 1000 μm, preferably 400 μm to 500 μm.

13. An article comprising a substrate and a film according to any one of claims 1 to 10.

14. The article according to claim 13, wherein The substrate is a solar cell.

15. A solar cell encapsulation material comprising a film according to any one of claims 1 to 10.

16. A laminate comprising a glass substrate and a film according to any one of claims 1 to 10.

17. The laminate according to claim 16, wherein, The laminate further comprises a backsheet, the backsheet comprising a polymer substrate or a second glass substrate.

18. The laminate according to claim 16, wherein, The laminate has an adhesion work of at least 150 N·mm according to ASTM D 3330.

19. The laminate according to claim 16, wherein, Under the UV lamp aging test at 1000W / m 2 and 65 °C, the decrease in the total light transmittance of the laminate is less than 1%.

20. The laminate according to claim 16, wherein, Under the damp heat test of 65 °C, 85% relative humidity, and UV exposure, the decrease in the total light transmittance of the laminate is less than 12%.

21. A method of manufacturing an article, comprising: Applying a film according to any one of claims 1 to 10 to a substrate.

22. The method according to claim 21, wherein said applying comprises: Vacuum laminating the film onto the substrate, wherein the film encapsulates and / or adheres a photovoltaic device to the substrate.

23. The method according to claim 21, wherein, The applying comprises: encapsulating a photovoltaic device by crosslinking the film via exposure to a vacuum lamination process, wherein the pressure is 5 kPa to 200 kPa, the temperature is 130 °C to 250 °C, and within a time frame of 1 minute to 2 hours.

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