Polyethylene copolymers and polyethylene terpolymers for solar cell encapsulation and methods thereof

Abstract

A thin film is provided, comprising a polymer composition comprising a polymer prepared from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, having an ethylene content in an amount ranging from 40% to 99.9% by weight and a melt index (I2) according to ASTM D1238 (190°C and 2.16 kg load) of 0.1 g / 10 min to 100 g / 10 min. Also provided are a thin film, a molded article comprising the thin film, a solar cell encapsulant comprising the thin film, a laminate comprising the thin film, and a method for producing the molded article.

Description

[Technical Field]

[0001] Solar cell encapsulants made with ethylene vinyl acetate (EVA) copolymers have challenges with degradation, especially in environments of high humidity, temperature, and sunlight incidence. This can lead to acetic acid production (which causes corrosion of metal components in the module), browning (which can result in reduced light transmittance and absorption due to chromophoric group formation), and loss of adhesion and flexibility, all of which negatively impact solar cell performance and present a challenge to the 30-year lifespan goal. [Background technology]

[0002] Traditional alternatives to EVA are materials such as ionomers, polyolefin elastomers (POE), thermoplastic olefins (TPO), and poly(siloxanes) (silicones). Ionomers have better performance (especially higher electrical resistivity and transmittance, and lower water vapor transmission rate), but are typically more expensive than EVA and therefore not accepted in such large markets. Polydimethylsiloxane (PDMS), the first material used as an encapsulant in photovoltaic (PV) modules, suffers from similar problems. Despite its superior performance (especially with regard to light transmittance), its high cost makes PDMS attractive only for niche, highly specialized, and demanding applications.

[0003] On the other hand, POE, a newer material on the market, is used through two approaches: crosslinking or as a thermoplastic. These crosslinked versions of thin films are manufactured using methods similar to those used for traditional EVA films. Peroxides, silanes, and additives are blended with the POE polymer, and the mixture is fabricated into thin films using either extrusion or calendaring methods, often designed for use in the same solar module manufacturing equipment with similar production cycle times as EVA. For thermoplastic versions, the silane additives used to ensure adhesion must be grafted prior to thin film fabrication and ensure mechanical stability at temperatures up to 105°C. Longer service life can be achieved by eliminating the acetic acid-related degradation mechanism from EVA. However, POE typically exhibits poorer adhesion performance, presenting challenges such as high cost and limited availability in the solar energy market. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2021 / 0102014 Summary of the Invention [Problem to be solved by the invention]

[0005] For EVA, the aforementioned degradation phenomena are caused / accelerated by exposure to UV radiation, heat, moisture, oxygen, and the catalytic activity of acetic acid. Therefore, there is a continuing need for cost-effective materials that reduce problems involving hydrolysis and UV degradation. [Means for solving the problem]

[0006] This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0007] In one aspect, embodiments disclosed herein relate to a thin film comprising a polymer composition comprising a polymer prepared from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, having an ethylene content in an amount ranging from 40% to 99.9% by weight, and having a melt index (I2) of 0.1 g / 10 min to 100 g / 10 min as measured according to ASTM D1238 (190°C and 2.16 kg load).

[0008] In another aspect, embodiments disclosed herein have an ethylene content in an amount ranging from 40% to 99.9% by weight, and meets ASTM a polymer composition comprising ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, having a melt index (I2) of 0.1 g / 10 min to 100 g / 10 min, as measured in accordance with ISO 1238 (190°C and 2.16 kg load), the polymer composition comprising ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate; and optionally: a peroxide; a crosslinking coagent; a first antioxidant; a second antioxidant; a light stabilizer; a UV absorber; an adhesion promoter; a heat stabilizer; a plasticizer; a rubber / elastomer; a filler; and combinations thereof; the blending method comprising using a twin-screw extruder, a single-screw extruder, a kneader, a Banbury mixer, a mixing roller, or a cast film extruder; and producing a thin film having a thickness in the range of 5 μm to 800 μm by cast film extrusion, blown film extrusion, or calendering.

[0009] In another aspect, embodiments disclosed herein relate to a molded article comprising a substrate and a thin film comprising a polymer composition comprising a polymer prepared from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, having an ethylene content in an amount ranging from 40% to 99.9% by weight, and having a melt index (I2) of 0.1 g / 10 min to 100 g / 10 min, as measured according to ASTM D1238 (190°C and 2.16 kg load).

[0010] In another aspect, embodiments disclosed herein relate to a solar cell encapsulant, comprising a thin film comprising a polymer composition comprising a polymer prepared from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, having an ethylene content in an amount ranging from 40% by weight to 99.9% by weight, and having a melt index (I2) of 0.1 g / 10 min to 100 g / 10 min, as measured according to ASTM D1238 (190°C and 2.16 kg load), wherein the thin film is crosslinked.

[0011] In another aspect, embodiments disclosed herein relate to a laminate comprising a glass substrate and a thin film comprising a polymer composition comprising a polymer prepared from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, having an ethylene content in an amount ranging from 40% to 99.9% by weight and having a melt index (I2) measured according to ASTM D1238 (190°C and 2.16 kg load) of 0.1 g / 10 min to 100 g / 10 min, wherein the thin film is on the glass substrate.

[0012] In another aspect, embodiments disclosed herein relate to a method of producing a molded article, the method comprising: applying a film comprising a polymer composition, the film comprising a polymer prepared from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, having an ethylene content in an amount ranging from 40% to 99.9% by weight and having a melt index (I2) of 0.1 g / 10 min to 100 g / 10 min, as measured according to ASTM D1238 (190°C and 2.16 kg load), to a substrate; and placing a second substrate on the film.

[0013] Other aspects and advantages of the claimed subject matter will become apparent from the following description and appended claims. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram illustrating a stacking cycle. [Figure 2] FIG. 2 is a schematic diagram of a lamination process. [Figure 3] FIG. 1 shows a laminated sample. [Figure 4] FIG. 1 shows initial UV-VIS spectroscopy of a laminated sample. [Figure 5] FIG. 1 shows the spectrum of a lamp used in a UV decomposition test and a high-temperature, high-humidity test. [Figure 6] FIG. 1 shows the results of a UV decomposition test. [Figure 7] FIG. 1 shows a comparison of transmittance of DV001A vs. EVATANE. [Figure 8] FIG. 1 shows a comparison of transmittance of DV001B versus EVATANE. [Figure 9] FIG. 1 shows a comparison of the transmittance of HM728 versus EVATANE. [Figure 10] FIG. 10 shows the index-angle coefficient (m) calculated from the numerically integrated data. [Figure 11] Figure 10 shows the index-linear coefficient (b) calculated from the numerically integrated data. [Figure 12]FIG. 1 shows the linear coefficient from the measured values ​​(initial transmittance - b0). [Figure 13] High temperature and humidity test - 65°C, 85% relative humidity, UV lamp transmittance of the sample. [Figure 14] FIG. 1 shows the transmittance of EVATANE and DV001A during high temperature and high humidity testing. [Figure 15] FIG. 1 shows the transmittance of EVATANE and DV001B during high temperature and high humidity testing. [Figure 16] FIG. 1 shows the transmittance of EVATANE and HM728 during high temperature and high humidity testing. [Figure 17] FIG. 1 shows the initial transmittance of DV001A, DV001B, HM728, and Evatane during high temperature and high humidity testing. [Figure 18] FIG. 1 shows plateau transmittance (linear fit) during high temperature and humidity testing. [Figure 19] Figure 19a shows the difference between the initial transmittance and the plateau transmittance (linear fit) during the HHT / HTS test - absolute value, and Figure 19b shows the difference between the initial transmittance and the plateau transmittance (linear fit) during the HHT / HTS test - normalized value w / initial transmittance. [Figure 20] FIG. 1 is a schematic diagram of a laminated adhesion test sample. [Figure 21] FIG. 10 shows a plot of force versus displacement highlighting the region used in the work and energy calculations and including highlighting the region not considered for HM728. [Figure 22] FIG. 10 shows a plot of force versus displacement highlighting the region used for the average force. DETAILED DESCRIPTION OF THE INVENTION

[0015]

[0003] Embodiments disclosed herein relate to thin films comprising a polymer composition comprising a polymer prepared from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, with the ethylene content ranging from 40% to 99.9% by weight. In one or more embodiments, the polymer composition can be prepared from the reaction of ethylene and one or more branched vinyl ester monomers and / or vinyl acetate monomers to modify various properties of the copolymer formed and the thin film formed therefrom, such as density, melt index (I2), melting point, electrical resistivity, hardness, softening point, light transmittance, haze, water vapor transmission rate, mechanical strength, UV cutoff wavelength, gloss, crystallinity, and glass transition temperature, among others.

[0016] Advantageously, the present disclosure aims to reduce the hydrolysis and degradation-related problems described herein for EVA through the use of copolymers and terpolymers of ethylene and branched vinyl esters, and optionally vinyl acetate. The inclusion of branched vinyl esters in place of or in conjunction with vinyl acetate can reduce water vapor transmission rates (WVTR) and acetic acid production while increasing low temperature flexibility.

[0017] polymer composition Copolymers and terpolymers The copolymers and terpolymers of the present disclosure can be made from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, and have an ethylene content in an amount ranging from 40% to 99.9% by weight.

[0018] Branched Vinyl Ester Monomer In one or more embodiments, the branched vinyl ester may include a branched vinyl ester derived from an isomeric mixture of branched alkyl acids. The branched vinyl ester according to the present disclosure has the general chemical formula (I):

[0019] [ka]

[0020] (In the formula, R 1 , R 2 , and R 3 may have a total carbon number ranging from C3 to C20. 1 , R 2 , and R 3 may all be alkyl chains with varying degrees of branching in some embodiments, or R 1 , R 2 , and R 3 A subset of may, in some embodiments, be independently selected from the group consisting of hydrogen, alkyl, or aryl.

[0021] In one or more embodiments, the vinyl carbonyl monomer has the general formula (II):

[0022] [ka]

[0023] (In the formula, R 4 and R 5 having a total of 6 or 7 carbon atoms), and the polymer composition has a number average molecular weight (M) in the range of 5 kDa to 10,000 kDa as determined by GPC. n In one or more embodiments, R 4 and R 5 may have a total carbon number of less than 6 or more than 7, and the polymer composition may have a M of up to 10,000 kDa. n That is, M n If R is less than 5 kDa, 4 and R 5 may have a total carbon number of less than 6 or more than 7, but M n When R is higher than 5 kDa, for example, in the range of 5 kDa to 10,000 kDa, 4 and R 5 may contain a total of 6 or 7 carbon atoms. In certain embodiments, R 4 and R5 has a total of 7 carbon atoms, and M n may be in the range of 5 kDa to 10,000 kDa. Furthermore, in one or more specific embodiments, the vinyl carbonyl of formula (II) may be used in combination with vinyl acetate.

[0024] Examples of branched vinyl esters include those with the following chemical structure:

[0025] [ka]

[0026] The monomer may include a monomer having the formula:

[0027] In one or more embodiments, the polymer composition may include polymers formed from monomers derived from petroleum and / or renewable resources.

[0028] In one or more embodiments, the branched vinyl ester may comprise a mixture of monomers and comonomers containing vinyl esters such as neononanoic acid, neodecanoic acid, etc. In some embodiments, the branched vinyl ester may comprise the Versatic™ Acid series tertiary carboxylic acids, such as Versatic™ Acid EH, Versatic™ Acid 9, and Versatic™ Acid 10, prepared by Koch synthesis, commercially available from Hexion™ Chemicals. In one or more embodiments, the polymer composition may comprise a polymer formed from monomers derived from petroleum and / or renewable resources.

[0029] Copolymers or terpolymers comprising branched vinyl ester monomers according to the present disclosure may have a proton nuclear magnetic resonance (NMR) content ranging from a lower limit selected from one of 40%, 45%, 50%, 55%, 60%, 65%, 70%, and 75% by weight to an upper limit selected from one of 75%, 80%, 85%, 90%, 95%, 99%, or 99.9% by weight.1 H NMR) and carbon-13 nuclear magnetic resonance ( 13 The range may include the weight percent of ethylene as measured by C NMR, and any lower limit may be paired with any upper limit.

[0030] The copolymer or terpolymer comprising branched vinyl ester monomers according to the present disclosure ranges from a lower limit selected from one of 0.01%, 0.1%, 1%, 5%, 10%, 20%, or 30% by weight to an upper limit selected from 30%, 35%, 40%, 45%, 50%, 55%, or 60% by weight. 1 H NMR and 13 It may include the weight percent of vinyl ester monomers, such as those of Formula (I) and Formula (II) above, as measured by C NMR, and any lower limit may be paired with any upper limit.

[0031] In some embodiments, copolymers or terpolymers comprising branched vinyl ester monomers according to the present disclosure optionally range from a lower limit selected from one of 0%, 0.01%, 0.1%, 1%, 5%, 10%, 20%, 25%, or 30% by weight, to an upper limit selected from 30%, 35%, 40%, 45%, 50%, 55%, or 59.99% by weight. 1 H NMR and 13 The range may include the weight percent of vinyl acetate as measured by C NMR, and any lower limit may be paired with any upper limit. For polymer samples containing vinyl acetate and vinyl ester monomers, 1 Because H NMR contains substantial overlap in both the carbonyl and alkyl regions for accurate integration, contamination is quantitative. 13 Evidence of branched vinyl ester and vinyl acetate contamination can be determined using C NMR. 13 It is observed in both the carbonyl region (170-180 ppm) and the alkyl region (0-50 ppm) in the C NMR spectrum (TCE-D2, 393.1 K, 125 MHz).1 The H NMR spectrum (TCE-D2, 393.2 K, 500 MHz) shows 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) suggesting long alkyl chains in the branched vinyl ester monomers. 1 H NMR spectrum and 13 The relative intensities of the peaks found in the C NMR spectra are used to calculate the monomer incorporation of branched vinyl esters and vinyl acetate in the copolymers / terpolymers.

[0032] Copolymers or terpolymers comprising branched vinyl ester monomers according to the present disclosure have a number average molecular weight (M), as measured by gel permeation chromatography (GPC), ranging 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. n ) (kilodaltons (kDa)), and any lower limit can be paired with any upper limit.

[0033] Copolymers or terpolymers comprising branched vinyl ester monomers according to the present disclosure have a weight average molecular weight (M), as measured by GPC, ranging 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. w ) (kilodaltons (kDa)), and any lower limit can be paired with any upper limit.

[0034] Copolymers or terpolymers comprising branched vinyl ester monomers according to the present disclosure may have a molecular weight distribution (M) as measured by GPC having a lower limit of any of 1, 1.5, 2, 5, or 10 and an upper limit of any of 20, 30, 40, 50, or 60. w M n and any lower limit may be paired with any upper limit.

[0035] GPC analysis can be carried out in a gel permeation chromatograph coupled with triple detection, equipped with an infrared detector IR5 and a 4-bridge capillary viscometer, both from PolymerChar, and an 8-angle light scattering detector from Wyatt. A 4-column, mixed-bed, 13 μm set from Tosoh can be used at a temperature of 140° C. Experiments can be carried out under the following conditions: concentration 1 mg / mL, flow rate 1 mL / min, dissolution temperature 160° C. and dissolution time 90 min, respectively, and injection volume 200 μL. The solvent used was TCB (trichlorobenzene) stabilized with 100 ppm BHT.

[0036] In one or more embodiments, copolymers or terpolymers comprising branched vinyl ester monomers according to the present disclosure can be prepared by polymerizing ethylene and one or more branched vinyl ester monomers, and optionally a vinyl acetate comonomer, in a reactor, as described, for example, in U.S. Patent Application Publication No. 2021 / 0102014, incorporated herein by reference in its entirety. The method of reacting the comonomer in the presence of a radical initiator may include any suitable method in the art, such as solution phase polymerization, radical polymerization under pressure, bulk polymerization, emulsion polymerization, and suspension polymerization. In some embodiments, the reactor may be a batch autoclave reactor at a temperature below 150°C and a pressure below 500 bar, known as a low-pressure polymerization system. In some embodiments, the comonomer and one or more free-radical polymerization initiators are polymerized in a continuous or batch mode at a temperature above 150°C and a pressure above 1000 bar, known as a high-pressure polymerization system. Copolymers and terpolymers produced under high pressure conditions may 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.

[0037] 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 includes a free-radical polymerization initiator in an amount of from about 0.001 millimole to about 0.01 millimole, calculated as the total amount of one or more initiators for free-radical polymerization, per liter of polymerization zone volume. The amount of ethylene in the polymerization zone will be determined primarily by the total reactor pressure, which may range from about 20 bar to about 100 bar, and the temperature, which may range from 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, and optionally a vinyl acetate comonomer, an initiator for free radical polymerization, 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, ether, dioxane, dimethylformamide (DMF), benzene, or acetone. Copolymers and terpolymers produced under low pressure conditions may exhibit number average molecular weights of 2 kDa to 20 kDa, weight average molecular weights of 4 kDa to 100 kDa, and MWDs of 2 to 5.

[0038] additives In one or more embodiments, the polymer composition according to the present disclosure may include one or more additives such as, but not limited to, crosslinkers, crosslinking coagents, primary antioxidants, secondary antioxidants, light stabilizers, UV absorbers, adhesion promoters, heat stabilizers, plasticizers, rubbers, elastomers, fillers, and combinations thereof.

[0039] Crosslinking agent The polymer compositions according to the present disclosure may include at least one crosslinking agent, which may include one or more peroxides capable of generating free radicals during polymer processing. In one or more embodiments, the peroxide may be a difunctional peroxide, such as benzoyl peroxide; dicumyl peroxide; di-tert-butyl peroxide; OO-Tert-amyl-O-2-ethylhexyl monoperoxycarbonate; tert-butyl cumyl peroxide; tert-butyl 3,5,5-trimethylhexanoate peroxide; tert-butyl peroxybenzoate; 2-ethylhexyl carbonate tert-butyl peroxide; 2,5-dimethyl-2,5-di(tert-butyl peroxide); butyl 4,4-di(tert-butylperoxide)valerate; di(2,4-dichlorobenzoyl)peroxide; di(4-methylbenzoyl)peroxide; di(tert-butylperoxyisopropyl)benzene peroxide; and the like.

[0040] Peroxides include benzoyl peroxide, 2,5-di(cumylperoxy)-2,5-dimethylhexane, 2,5-di(cumylperoxy)-2,5-dimethylhexyne-3,4-methyl-4-(t-butylperoxy)-2-pentanol, butyl-peroxy-2-ethyl-hexanoate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, t-butyl-peroxy-benzoate, t-butyl-peroxy-2-ethyl-hexanoate, 4-methyl-4-(t-amylperoxy)-2-pentanol ... 4-(cumylperoxy)-2-pentanol, 4-methyl-4-(t-butylperoxy)-2-pentanone, 4-methyl-4-(t-amylperoxy)-2-pentanone, 4-methyl-4-(cumylperoxy)-2-pentanone, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-amylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(t-amylperoxy)hexyne-3, 2,5-dimethyl- 2-t-butylperoxy-5-hydroperoxyhexane, 2,5-dimethyl-2-cumylperoxy-5-hydroperoxyhexane, 2,5-dimethyl-2-t-amylperoxy-5-hydroperoxyhexane, m / p-alpha,alpha-di[(t-butylperoxy)isopropyl]benzene, 1,3,5-tris(t-butylperoxyisopropyl)benzene, 1,3,5-tris(t-amylperoxyisopropyl)benzene, 1,3,5-tris(cumylperoxyisopropyl)benzene, di[1,3-dimethyl-3- (t-butylperoxy)butyl]carbonate, di[1,3-dimethyl-3-(t-amylperoxy)butyl]carbonate, di[1,3-dimethyl-3-(cumylperoxy)butyl]carbonate, di-t-amyl peroxide, t-amyl cumyl peroxide, t-butyl-isopropenylcumyl peroxide, 2,4,6-tri(butylperoxy)-s-triazine, 1,3,5-tri[1-(t-butylperoxy)-1-methylethyl]benzene, 1,3,5-tri-[(t-butylperoxy)-isopropyl]benzene, 1,3-Dimethyl-3-(t-butylperoxy)butanol, 1,3-dimethyl-3-(t-amylperoxy)butanol, di(2-phenoxyethyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, dimyristyl peroxydicarbonate, dibenzyl peroxydicarbonate, di(isobomyl)peroxydicarbonate, 3-cumylperoxy-1,3-dimethylbutyl methacrylate, 3-t-butylperoxy-1,3-dimethylbutyl methacrylate , 3-t-amylperoxy-1,3-dimethylbutyl methacrylate, tri(1,3-dimethyl-3-t-butylperoxybutyloxy)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-methyl ethylethenyl)-phenyl}-1-methylethyl]carbamate, 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-di(t-butylperoxy)cyclohexane, n-butyl 4,4-di(t-amylperoxy)valerate, ethyl 3,3-di(t-butylperoxy)butyrate, 2,2-di(t-amylperoxy)propane, 3,6,6,9,9-pentamethyl-3-ethoxycarbonylmethyl-1,2,4,5-tetraoxacyclononane, n-butyl-4,4-bis(t-butylperoxy) oxy)valerate, ethyl-3,3-di(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 methyl ethyl ketone peroxide cyclic trimer), methyl ethyl ketone peroxide cyclic dimer, 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane, 2,5-dimethyl-2,5-Di(benzoylperoxy)hexane, t-butyl perbenzoate, t-butyl peroxyacetate, t-butylperoxy-2-ethylhexanoate, t-amyl perbenzoate, t-amyl peroxyacetate, t-butylperoxyisobutyrate, 3-hydroxy-1,1-dimethyl t-butylperoxy-2-ethylhexanoate, OO-t-amyl-O-hydrogen-monoperoxysuccinate, OO-t- Butyl-O-hydrogen-monoperoxysuccinate, di-t-butyl diperoxyphthalate, t-butylperoxy(3,3,5-trimethylhexanoate), 1,4-bis(t-butylperoxycarbo)cyclohexane, t-butylperoxy-3,5,5-trimethylhexanoate, t-butyl-peroxy-(cis-3-carboxy)propionate, allyl 3-methyl-3-t-butylperoxybutyrate, OO- t-Butyl-O-isopropyl monoperoxycarbonate, OO-t-butyl-O-(2-ethylhexyl) monoperoxycarbonate, 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 Also included may be mentioned peroxypropane, OO-t-amyl-O-isopropyl monoperoxycarbonate, di(4-methylbenzoyl)peroxide, di(3-methylbenzoyl)peroxide, di(2-methylbenzoyl)peroxide, didecanoyl peroxide, dilauroyl peroxide, 2,4-dibromo-benzoyl peroxide, succinic peroxide, dibenzoyl peroxide, di(2,4-dichloro-benzoyl)peroxide, and combinations thereof.

[0041] The amount of crosslinker may range from a lower limit of 0.001 rubber / 100 parts by weight of resin (phr), 0.01 phr, 0.1 phr, 0.5 phr, 1 phr, or 2 phr, per 100 phr of polymer, to an upper limit of 2 phr, 3 phr, 4 phr, or 5 phr, any lower limit may be used in combination with any suitable upper limit. In one or more embodiments, the crosslinker may be in an amount ranging from 0.1 phr to 2.5 phr, or even from 0.5 phr to 2 phr.

[0042] Crosslinking aid In one or more embodiments, the polymer compositions according to the present disclosure may include one or more crosslinking coagents. Crosslinking coagents provide additional reactive sites for crosslinking, allowing the degree of polymer crosslinking to be significantly increased beyond that typically achieved by the addition of peroxide alone. Generally, the coagent increases the rate of crosslinking. In one or more embodiments, the crosslinking coagent may include triallyl isocyanurate (TAIC), trimethylolpropane-tris-methacrylate (TRIM), triallyl cyanurate (TAC), trifunctional (meth)acrylate ester (TMA), N,N'-m-phenylenedimaleimide (PDM), poly(butadiene) diacrylate (PBDDA), high-vinyl poly(butadiene) (HVPBD), polytransoctenamer rubber (TOR) (Vestenamer®), and combinations thereof.

[0043] The amount of coagent may range from a lower limit of 0.01 parts by weight of rubber / 100 parts by weight of resin (phr), 0.1 phr, 0.5 phr, 1 phr, or 2 phr, per 100 phr of polymer, to an upper limit of 2 phr, 2.5 phr, 3 phr, 3.5 phr, 4 phr, 4.5 phr, or 5 phr, any lower limit may be used in combination with any suitable upper limit. In one or more embodiments, the coagent may be in an amount ranging from 0.1 phr to 2.5 phr.

[0044] antioxidants In one or more embodiments, the polymer composition according to the present disclosure may include one or more antioxidants. The polymer composition according to an embodiment may include at least a first antioxidant and a second 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.

[0045] Monophenolic antioxidants include, inter alia, 2,6-di-tert-butyl-p-cresol, butylhydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, etc. Bisphenolic 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-tetroxaspiro-5,5-undecane, etc. Polymeric phenolic antioxidants include 1,1,3-tris(2- methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tetrakis-methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate methane, bis{(3',3'-bis-4'-hydroxy-3'-tert-butylphenyl)butyric acid glucose ester, 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)trione, and triphenol (vitamin E).

[0046] Sulfur-containing antioxidants include dilauroyl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiopropionate.

[0047] Phosphite-type antioxidants include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl-ditridecyl) phosphite, cyclic neopentane-tetraylbis(octadecyl) phosphite, tris(mono- and / or di)phenyl phosphite, diisodecyl pentaerythritol, 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 neopentane-tetraylbis(2,4-di-tert-butylphenyl)phosphite, cyclic neopentane-tetraylbis(2,6-di-tert-methylphenyl)phosphite, and 2,2-methylenebis(4,6-tert-butylphenyl)octylphosphite.

[0048] In one or more embodiments, phenolic and phosphite type antioxidants may be used alone or, preferably, in combination to increase thermal stability.

[0049] The amount of antioxidant added may range from a lower limit of 0.001 parts by weight per 100 rubber / resin (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 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, per 100 phr of polymer, any lower limit being combinable with any suitable upper limit. In one or more embodiments, the antioxidant may be in an amount ranging from 0.01 phr to 0.5 phr.

[0050] Light stabilizers The use of light stabilizers (LS), especially hindered amine-type (HALS), when combined with UV absorbers, produces significant synergistic effects. While other typical LS compounds can perform the same role as HALS, many of them cause color in polymer compounds and are therefore undesirable for use in solar cell encapsulants. Hindered amine-type light stabilizers are generally secondary amines, tertiary amines, acetylated amines, N-hydrocarbyloxy-substituted amines, hydroxy-substituted amines, or other substituted cyclic amines with a significant amount of steric hindrance.In particular, light stabilizers include molecules such as dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensates, 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-di-tert-4-hydroxybenzyl)-2-n-butylmalonate, propanedioic acid, C4-(methoxyphenyl)-methylene-, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)ester, polymethylpropyl-3-oxy-4-(2,2,6,6-tetramethyl)piperidin Nylsiloxane, 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidinyl)-2,5-pyrrolidinedione, 1,3,5-triazine-2,4,6-triamine, N,'N'-1,2-ethanediylbis4,6-bisbutyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino-1,3,5-triazin-2-yl)imino-3,1propanediyl)-bisN',N'-dibutyl-N',N'-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-(Chimasorb 119, CAS Registry Number 106 990-43-6); polymer containing N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine, 2,4,6-trichloro-1,3,5-triazine, and 2,4,4-trimethyl-1,2-pentamine (Chimasorb 944, ACS Registry Number 70624-18-9); and N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine polymer with 2,4,6-trichloro-1,3,5-triazine and tetrahydro-1,4-oxazine.

[0051] The amount of light stabilizer may range 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, per 100 phr of polymer, and any lower limit may be used in combination with any suitable upper limit. In one or more embodiments, the light stabilizer may be present in an amount ranging from 0.01 phr to 0.3 phr.

[0052] UV absorber Any known UV absorber may be utilized within the present disclosure. General classes of preferred UV absorbers are benzophenones, benzotriazoles, triazines, salicylates, hydroxybenzophenones, hydroxyphenyltriazines, esters of substituted and unsubstituted benzoic acids, and the like, and mixtures thereof.

[0053] 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.

[0054] Benzotriazole UV absorbers include hydroxyphenyl-substituted benzotriazole compounds such as 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy5-t-butylphenyl)benzotriazole, 2-(2-hydroxy-3,5-dimethylphenyl)benzotriazole, 2-(2-methyl-4-hydroxyphenyl)benzotriazole, 2-(2-hydroxy-3-methyl-5-t-butylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di-t-amylphenyl)benzotriazole, and 2-(2-hydroxy-3,5-di-t-butylphenyl)benzotriazole.

[0055] 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 UV absorbers include phenyl salicylate and p-octylphenyl salicylate.

[0056] The amount of UV absorber may range from a lower limit of 0.001 parts by weight per 100 rubber / resin (phr), 0.01 phr, 0.1 phr, 0.2 phr, 0.3 phr, 0.4 phr, or 0.5 phr per 100 phr of polymer, to an upper limit of 0.5 phr, 1.0 phr, 2.0 phr, 3.0 phr, 4.0 phr, or 5.0 phr, any lower limit may be used in combination with any suitable upper limit. In one or more embodiments, the UV absorber may be in an amount ranging from 0.01 phr to 0.5 phr.

[0057] Adhesion promoter The most used adhesion promoters are silane coupling agents, which are effective in improving the adhesive strength of the encapsulant to protective materials (front sheets, back sheets, etc., made of glass or polymer) and solar cell components, such as photovoltaic elements, metal grids, etc. Compounds containing unsaturation (e.g., vinyl groups), acryloxy or methacryloxy groups, amino groups, epoxy groups, etc., and additionally having hydrolyzable groups such as alkoxy groups, are viable molecules as coupling agents.

[0058] Some specific molecules that fit the aforementioned classification are γ-chloropropyl methoxysilane, vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tris(β-methoxyethoxy)silane, γ-vinylbenzylpropyl trimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyl trimethoxysilane, vinyl triacetoxysilane, γ-glycidoxypropyl triethoxysilane, β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, vinyl trichlorosilane, γ-mercaptopropyl methoxysilane, γ- aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-(3-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(3-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, etc., the last two being the best choices for this application as they provide good adhesion and are almost free from color issues, e.g., yellowing, upon grafting / reaction.

[0059] The amount of silane coupling agent may range 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, relative to 100 phr of the polymer, and any lower limit may be used in combination with any suitable upper limit. In one or more embodiments, the silane coupling agent may be in an amount ranging from 0.1 phr to 3 phr.

[0060] heat stabilizer Heat stabilizers can be used as optional additives in solar cell encapsulants 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 malonates, aromatic hydroxybenzyl compounds, triazine compounds, amine antioxidants, arylamines, diarylamines, polyarylamines, acylaminophenols, oxamides, metal deactivators, phosphites, phosphonites, benzyl phosphonates, ascorbic acid (vitamin C), peroxide deactivators, hydroxylamines, nitrones, thiosynergists, benzofuranones, indolinones, and mixtures thereof. Its use is optional and in some cases is undesirable (especially when it severely suppresses crosslinking).

[0061] The heat stabilizer may be present in an amount ranging 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, per 100 phr of polymer, and any lower limit may be used in combination with any suitable upper limit. In one or more embodiments, the heat stabilizer may be present in an amount ranging from 0.01 phr to 1 phr.

[0062] plasticizerThe polymer compositions according to the present disclosure may contain one or more plasticizers to adjust the physical properties and processability of the composition. In some embodiments, plasticizers according to the present disclosure include bis(2-ethylhexyl) phthalate (DEHP), di-isononyl phthalate (DINP), bis(n-butyl) phthalate (DNBP), butyl benzyl phthalate (BZP), di-isodecyl phthalate (DIDP), di-n-octyl phthalate (DOP or DNOP), di-o-octyl phthalate (DIOP), diethyl phthalate (DEP), di-isobutyl phthalate (DIBP), di-n-hexyl phthalate, tri-methyl trimellitate (TMTM), tri-(2-ethylhexyl) trimellitate (TEHTM-MG), tri-(n-octyl, n-decyl) trimellitate, tri-(heptyl, nonyl) trimellitate, n-octyl trimellitate, among other plasticizers and polymeric plasticizers. , bis(2-ethylhexyl) adipate (DEHA), dimethyl adipate (DMD), mono-methyl adipate (MMAD), dioctyl adipate (DOA), dibutyl sebacate (DBS), polyesters of adipic acid such as VIERNOL, dibutyl maleate (DBM), di-isobutyl maleate (DIBM), benzoates, epoxidized soybean oil and derivatives, n-ethyltoluenesulfonamide, n-(2-hydroxypropyl)benzenesulfonamide, n-(n-butyl)benzenesulfonamide, tricresyl phosphate (TCP), tributyl phosphate (TBP), glycols / polyesters, triethylene glycol dihexanoate (3gh), tetraethylene glycol diheptanoate, polybutenes, acetylated monoglycerides;Included may be one or more of alkyl citrate, triethyl citrate (TEC), acetyl triethyl citrate, tributyl citrate, acetyl tributyl citrate, trioctyl citrate, acetyl trioctyl citrate, trihexyl citrate, acetyl trihexyl citrate, butyryl trihexyl citrate, trihexyl o-butyryl citrate, trimethyl citrate, alkyl sulfonic acid phenyl ester, 2-cyclohexanedicarboxylic acid di-isononyl ester, nitroglycerin, butanetriol trinitrate, dinitrotoluene, trimethylolethane trinitrate, diethylene glycol dinitrate, triethylene glycol dinitrate, bis(2,2-dinitropropyl) formal, bis(2,2-dinitropropyl) acetal, 2,2,2-trinitroethyl 2-nitroxyethyl ether, mineral oil, vegetable oil, or bio-based oil. In certain embodiments, one of the one or more plasticizers may be mineral oil;

[0063] The polymer composition according to the present disclosure may optionally include a plasticizer in an amount ranging from 0 phr to 20 phr. The plasticizer can 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, any lower limit being combinable with any suitable upper limit.

[0064] thin film In one or more embodiments, thin films can be prepared comprising the above-described polymer compositions, particularly copolymers or terpolymers. The thin films can be prepared by cast film extrusion, blown film extrusion, calendering, or any method suitable for preparing thin films. Thin films according to the present disclosure can be suitable for use as solar cell encapsulants, tie layers, and glass laminate structures. The thin films can be uncrosslinked or crosslinked.

[0065] A thin film according to one or more embodiments may comprise a polymer (copolymer or terpolymer) having a total comonomer content (branched vinyl ester and optional vinyl acetate) ranging from a lower limit selected from one of 5%, 10%, 15%, 20%, 25%, or 30% by weight to an upper limit selected from 30%, 35%, 40%, 45%, 50%, 55%, or 60% by weight, any lower limit being combinable with any suitable upper limit.

[0066] The thin film according to one or more embodiments has a density of 0.8 g / cm 3 , 0.9g / cm 3 , 0.905g / cm 3 , 0.91g / cm 3 , 0.915g / cm 3 , 0.92g / cm 3 , 0.925g / cm 3 , 0.93g / cm 3 0.95 g / cm 3 , 0.955g / cm 3 , 0.96g / cm 3 , 0.965g / cm 3 , 0.97g / cm 3 , 0.98g / cm 3 , 0.99g / cm 3 , 1.0g / cm 3 , 1.1g / cm 3 , 1.2g / cm 3 , or 1.3 g / cm 3 to an upper limit selected from one of the following, any lower limit can be combined with any suitable upper limit.

[0067] A thin film according to one or more embodiments may comprise a polymer (copolymer or terpolymer) having a melt index (I2), as measured according to ASTM D1238 (190°C and 2.16 kg load), ranging 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, any lower limit can be combined with any suitable upper limit.

[0068] Thin films according to one or more embodiments may have a thickness ranging 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, any lower limit being combinable with any suitable upper limit.

[0069] Solar cell encapsulant As previously mentioned, the thin films of the present disclosure may be used as solar cell encapsulants, where the thin films may be applied to solar cells or photovoltaic (PV) cells as substrates.

[0070] PV cells may be crystalline, semi-crystalline, or amorphous and are generally packaged in multiple protective layers including a front cover, a sealing film, and a back sheet, for example, a five-layer laminate of front cover / sealing film / PV cell and electrical wiring / sealing film / back sheet. The polymer compositions and thin films containing the polymer compositions of the present disclosure can be used, inter alia, as encapsulants.

[0071] In addition to the copolymer or terpolymer described herein, thin films for use as solar cell encapsulants may include one or more of: a crosslinking agent in an amount of 0.01 phr to 10 phr; a crosslinking coagent in an amount of 0.01 phr to 5 phr; a first antioxidant in an amount of 0.01 phr to 5 phr; a second 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.

[0072] In one or more embodiments, a thin film suitable for use as a solar cell encapsulant has a density of 0.92 g / cm 3 , 0.925g / cm 3 , 0.93g / cm 3 , 0.935g / cm 3 , or 0.94 g / cm 3 0.95 g / cm 3 , 0.955g / cm 3 , 0.96g / cm 3 , 0.965g / cm 3 , or 0.97 g / cm 3 to an upper limit selected from one of the following: 0.93 g / cm 3 ~0.96g / cm 3 The density may range from .gtoreq. ...

[0073] In one or more embodiments, thin films suitable for use as solar cell encapsulants may comprise polymers having a melt index (I2), as measured according to ASTM D1238 (190°C and 2.16 kg load), 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, any lower limit can be combined with any suitable upper limit. In one or more embodiments, the polymer may have a melt index (12) in the range of 2 g / 10 min to 200 g / 10 min, or even in the range of 5 g / 10 min to 50 g / 10 min.

[0074] In one or more embodiments, a thin film suitable for use as a solar cell encapsulant may include a polymer having a melting point, as 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, any lower limit being combinable with any suitable upper limit. In one or more embodiments, the polymer may include a melting point below 90°C, or a melting point in the range of 60°C to 80°C.

[0075] In one or more embodiments, thin films suitable for use as solar cell encapsulants have a surface area of ​​1×10 14 Greater than 1 x 10 ohm.cm 15 It may also include polymers having a volume electrical resistivity, measured according to ASTM D257, greater than ohm.cm.

[0076] In one or more embodiments, a thin film suitable for use as a solar cell encapsulant may include a polymer having a Shore A hardness of less than 90 Shore A or less than 80 Shore A as measured according to ASTM D2240.

[0077] In one or more embodiments, thin films suitable for use as solar cell encapsulants may include polymers having a Vicat softening point, measured according to ASTM D1525, of 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.

[0078] In one or more embodiments, a thin film suitable for use as a solar cell encapsulant may include a polymer having a contact angle, measured according to ASTM D5946, of greater than 70°, or greater than 75°, or greater than 80°, or greater than 85°, or greater than 90°.

[0079] In one or more embodiments, thin films suitable for use as solar cell encapsulants may have a light transmittance, as measured according to ASTM D1003, of 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%.

[0080] In one or more embodiments, thin films suitable for use as solar cell encapsulants may have a haze of 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%.

[0081] In one or more embodiments, thin films suitable for use as solar cell encapsulants have a water vapor transmission coefficient of 25000 μm.g / m as measured according to ASTM F1249. 2 Less than .day, 24000μm.g / m 2 Less than .day, 23000μm.g / m 2 .day, less than 22000μm.g / m 2 Less than .day, 21000μm.g / m 2 Less than .day or 20000μm.g / m 2 May have less than .day.

[0082] In one or more embodiments, thin films suitable for use as solar cell encapsulants may have a stress at break 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.

[0083] In one or more embodiments, thin films suitable for use as solar cell encapsulants may have a strain at break 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%.

[0084] In one or more embodiments, thin films suitable for use as solar cell encapsulants may be crosslinked and have a UV cutoff wavelength of 380 nm, or even 360 nm, as measured by UV / Vis spectroscopy or UV / Vis / NIR spectroscopy.

[0085] In one or more embodiments, thin films suitable for use as solar cell encapsulants may exhibit a 45° gloss of at least 70%, at least 73%, at least 77%, or at least 80%, as measured according to ASTM D2457.

[0086] In one or more embodiments, thin films suitable for use as solar cell encapsulants can exhibit a gloss at 60° of at least 80%, at least 85%, at least 90%, or at least 95%, as measured according to ASTM D2457.

[0087] In one or more embodiments, a thin film suitable for use as a solar cell encapsulant may comprise a polymer composition that exhibits a glass transition temperature, measured via tan δ, 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.

[0088] In one or more embodiments, a thin film suitable for use as a solar cell encapsulant may comprise a polymer composition that exhibits a glass transition temperature, as measured via loss modulus, 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.

[0089] Thin film preparation method

[0010] Embodiments disclosed herein may relate to a method for preparing a thin film comprising a polymer composition according to the present disclosure. The method may include preparing a polymer composition by blending a polymer prepared from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate according to embodiments described herein, and optionally one or more of peroxides, crosslinking coagents, first antioxidants, second antioxidants, light stabilizers, UV absorbers, adhesion promoters, and heat stabilizers, plasticizers, rubbers / elastomers, fillers, and combinations thereof.

[0090] The blending step can be carried out by any suitable method and may include using a twin screw extruder, a single screw extruder, a kneader, a Banbury mixer, a mixing roller, or a cast film extruder.

[0091] The prepared polymer composition can then be used to prepare a thin film comprising the polymer composition, which can be made by cast film extrusion, blown film extrusion, calendering, or any other suitable method.

[0092] molded product The embodiments disclosed herein may relate to a molded article comprising at least one thin film disclosed herein. The molded article may comprise a substrate to which the thin film is applied. The molded article may comprise one or more substrates rather than a single substrate. For example, the molded article may be an encapsulated solar cell.

[0093] Method for manufacturing molded articles

[0010] Embodiments disclosed herein may relate to methods of making a molded article including a thin film according to embodiments disclosed herein. The method may include applying the thin film to a substrate, where the applying step includes vacuum laminating a thin film according to the present disclosure to the substrate, where the thin film seals and / or bonds a photovoltaic element to the substrate. Sealing the photovoltaic element may include cross-linking the thin film according to the present disclosure by undergoing a vacuum lamination process.

[0094] The vacuum lamination process can be carried out at pressures ranging 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, any lower limit being combined with any suitable upper limit.

[0095] The vacuum lamination process can be carried out at temperatures ranging 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, any lower limit can be combined with any suitable upper limit.

[0096] The vacuum lamination process can be carried out for a time frame ranging from a lower limit of 0.5 minutes, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 10 minutes, 20 minutes, 30 minutes, to an upper limit of 60 minutes, 75 minutes, 90 minutes, or 2 hours, any lower limit being combinable with any suitable upper limit.

[0097] Materials, Experimental Methods, and Characterization material Compositions based on ethylene, vinyl acetate, and vinyl neodecanoate (VeoVA™ 10) were tested. Terpolymer samples DV001A and DV001B were produced in a high-pressure industrial asset normally operated to produce EVA copolymers. Typical reactor conditions for the production of the terpolymers are listed in Table 1.

[0098] [Table 1]

[0099] Evidence of branched vinyl ester and vinyl acetate contamination 13 It is found in both the carbonyl region (170 ppm to 180 ppm) and the alkyl region (0 ppm to 50 ppm) of the C NMR spectrum (TCE-D2, 393.1 K, 125 MHz). 1 The H NMR spectrum (TCE-D2, 393.2 K, 500 MHz) shows vinyl acetate and branched vinyl ester peaks (4.7 ppm to 5.2 ppm) and ethylene peaks (1.2 ppm to 1.5 ppm), as well as additional peaks in the alkyl region (0.5 ppm to 1.5 ppm) suggesting the long alkyl chains of the branched vinyl ester monomers. 1 H NMR spectrum and 13 The relative intensities of the peaks found in the C NMR spectra are used to calculate the monomer incorporation of branched vinyl esters and vinyl acetate in the copolymers / terpolymers.

[0100] Neat polymer characterization The contents of VA and VeoVa™ 10 were as described above. 1 H NMR and 13 The melting and crystallization behavior of the samples was studied by C NMR. The experiments were carried out on a TA Instruments DSC Discovery - DSC2500 in nitrogen 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.

[0101] Density was measured according to ASTM D792, Vicat softening point (10 N) according to ASTM D1525, hardness (Shore A) according to ASTM D2240, contact angle according to ASTM D5946, and volume electrical resistivity according to ASTM D257. Test specimens for density, Vicat, hardness, contact angle, and volume electrical resistivity measurements were prepared by compression molding according to ASTM D4703 and conditioned at 23°C and 50% RH for at least 24 hours. Melt flow rate was evaluated at 190°C and 2.16 kg according to ASTM D1239.

[0102] Neat and Compound Thin Film Extrusion Cast films of the aforementioned polymers (neat) and the compounds described in Example 3 were produced in a Leonard OCS ME-20 / 2800-V3 cast film extruder equipped with a flat die and a chilled towing roll. Prior to extrusion, the die was cleaned with a spatula and brass wool. To evaluate the processability and aesthetics of the films under these conditions, the temperature profile and melting point were limited to 140°C (less than 120°C for the formulations). Due to the strong adhesion of the EVA film to the pinch roll, the EVA film was previously covered with brown paper and cooled to approximately 9°C.

[0103] Thin film characterization Relevant properties (optical, mechanical, and barrier) were tested on neat thin films of the polymer and are shown in the table below. Water vapor transmission rate and degree of crosslinking by gel content in boiling xylene can also be measured on crosslinked thin films (as described in Example 4).

[0104] Optical properties (clarity, haze, and transmittance) were measured as defined by ASTM D1003, gloss (45° and 60°) was measured according to ASTM D2457, water vapor transmission rate was measured according to ASTM F1249 (37.8°C, 100 RH, 1 atm), and tensile tests were performed using an optical extensometer according to ASTM D882 (crosshead speed 500 mm / min), and stress and strain at yield and break, and secant modulus (1%) were reported.

[0105] Compression Molded Samples - Cross-Linking Procedure The samples were cross-linked according to ASTM D4703 by compression molding (standard heating cycle followed by 150° C. for 1 hour at normal pressure, followed by a standard cooling cycle).

[0106] Characterization of cross-linked compression molded samples Cross-linked compression molded specimens were tested for 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 (according to ASTM D3418, tested from -20°C to 200°C, heating rate 10°C / min), gel content (internal method according to ASTM D2765 - mesh #120 sieve, boiling xylene extraction for 8 hours, followed by oven drying at 100°C to 150°C until constant mass was obtained (approximately 1 hour)), and DMA (tensile mode, -150°C to 150°C, heating rate 3°C / min, deformation amplitude 15 microns).

[0107] The glass transition temperatures (T g ) was determined from the measurement of the Tan δ peak maximum of the sample during DMA measurement using a TA800 DMA instrument in tensile mode. Thin films (approximately 0.5 mm) were compression molded at 150 °C and o The specimen was cooled to 30°C and its viscoelastic response was measured at a rate of 30°C while a preload of 0.01 N was applied at a frequency of 1 Hz and an amplitude of 15 μm. oThe storage modulus, loss modulus, and tan δ (the ratio of storage modulus to loss modulus) were recorded as a function of temperature. [Example]

[0108] Example 1 Neat Polymer Characterization - The basic properties of the aforementioned terpolymers (designated DV001A, DV001B) and EVA benchmarks - Braskem SA grade HM728 and SK Chemicals Co. grade EVATANE 3345PV - are shown in Table 2.

[0109] [Table 2]

[0110] Volume electrical resistivity was measured according to ASTM D257 on neat parts (2 mm thick) compression molded according to ASTM D4703, and the results are shown in Table 3.

[0111] [Table 3]

[0112] The volume resistivity of the terpolymers exhibits very similar values ​​compared to HM728, with the average value for DV001B being slightly higher. The three aforementioned grades exhibit significantly higher resistivity than EVATANE 3345PV. High volume resistivity values ​​are desirable for these applications, as electrical leakage or breakdown is highly undesirable as it can impair module efficiency or even destroy its function.

[0113] Example 2 Neat thin films were prepared according to the thin film extrusion procedure described above. The films were collected and rolled with brown paper to prevent blocking. The extrusion parameters were as follows:

[0114] [Table 4]

[0115] The films were characterized according to the methods described above. Overall, similar optical properties were observed, with slightly higher clarity and lower haze for the terpolymers compared to HM728, as shown in Tables 5 and 6. Evatane exhibited better optical properties but was also easier to extrude due to its higher MFR, which significantly affected the optical properties. As shown in Table 7, lower water vapor transmission coefficients were observed for the terpolymers, especially DV001B, which contained the most VeoVa™ 10 monomer.

[0116] [Table 5]

[0117] [Table 6]

[0118] [Table 7]

[0119] Example 3 The following formulations were prepared with all the materials mentioned above in a twin-screw extruder ZSK-26 by Coperion, followed by strand cooling in a water bath and then pelletizing. As shown in Table 8, sample preparation consisted of micronizing approximately 20% by weight of EVA (cryogenic conditions - liquid N2) to better absorb the liquid peroxide, followed by dry blending all ingredients in a plastic bag, and finally feeding into the main feeder of the extruder at the specific extrusion conditions shown in Table 9.

[0120] [Table 8]

[0121] [Table 9]

[0122] The samples were cross-linked and characterized according to the methods described above. Despite the difference in thickness compared to the compression molded plates, the cross-linked material exhibited a significant increase in break stress compared to the neat polymer.

[0123] [Table 10]

[0124] Glass transition temperatures were obtained for both neat and cross-linked thin films prepared according to the above method. The results are as follows:

[0125] [Table 11]

[0126] T for terpolymer g are very similar to each other and are comparable to the values ​​measured for EVA with 33% by weight VA (EVATANE 3345PV) when neat (slightly higher via tan δ and lower via loss modulus) and also when cross-linked (lower via tan δ and loss modulus). Again, both terpolymers have lower T values ​​than EVA with 28% by weight VA (HM728). g This suggests that the studied terpolymers exhibit good low-temperature flexibility, possibly even better than the commercial products.

[0127] When neat, EVATANE has a slightly lower T via tan δ. gand slightly higher peaks, which indicates higher segment mobility (as it is a polymer with lower crystallinity), followed by the terpolymers (which are very similar to each other), and finally a slightly higher T g and HM728, which has a lower tan δ peak. A similar trend was observed for the cross-linked polymers, but the cross-linked terpolymer exhibits behavior even closer to EVATANE 3345PV.

[0128] The gel content by boiling xylene extraction was determined according to the method described above, and the results are as follows:

[0129] [Table 12]

[0130] The thermal properties of the neat and cross-linked samples were determined by DSC according to the method described above. Cross-linked samples were cut from tensile test dog bones, and neat samples were cast into thin films. As shown in Table 13, the same trends as for the neat polymers are observed for the cross-linked samples, with slightly lower Tm2, ​​Tc, and ΔHm (enthalpy of fusion) for DV001A compared to HM728, but a significant Tc decrease for the terpolymer containing 5 wt% VeoVA™ 10.

[0131] [Table 13]

[0132] The DSC data also generally indicated a trend for lower Tm and enthalpy of fusion for EVATANE compared to the other materials for the neat polymer. All materials exhibited lower Tm, Tc, and ΔH when crosslinked, possibly due to reduced crystallinity and lamellar thickness resulting from the restriction of molecular chain mobility imparted by crosslinking.

[0133] DV001A exhibits lower Tm, Tc, and ΔHm than HM728, which is consistent with the results seen for optical properties, hardness, modulus, tensile, and Vicat. As seen in Example 4, DV001B exhibited essentially the same thermal behavior as HM728, but slightly better optical properties.

[0134] Example 4 Films of the extruded formulation were produced by cast film extrusion using the same techniques / careful considerations as the neat films (except that brown paper was not used to cover the chill roll). The extrusion parameters were as follows:

[0135] [Table 14]

[0136] Thin films of the samples were cured by compression molding using a Teflon® sheet to avoid adhesion to the substrate. Large pressure (3.5 tons) was not applied to avoid significantly changing the thickness of the sheet. The molding process was carried out at 160°C for 60 minutes. After molding, the samples were cooled on a bench (concrete) at a non-specific cooling rate, and the Teflon® sheet was carefully removed to avoid damaging the sheet.

[0137] The samples were tested for water vapor transmission rate and gel content as previously described. As shown in Table 15, water vapor transmission rate was determined according to ASTM F1249 using the following conditions: 37.8°C, 1 atm, 100% relative humidity with a method uncertainty of 5%.

[0138] [Table 15]

[0139] The gel content of the films was determined by boiling xylene extraction according to the method previously described, with the following results:

[0140] [Table 16]

[0141] Example 5 Aging test (UV decomposition and high temperature / humidity test) The compounded thin film described above and additional standard commercial Sentryglass (Kuraray Co.) were laminated between glass substrates.

[0142] The material was placed in a vacuum (-90 kPa) laminator (Radiant Solar Panel Laminator YDS-0707, Yudian Solar Co. Ltd.) that was heated to 100°C for 30 minutes to melt the EVA and spread and fill the voids in the laminate. The application of vacuum helps remove air and eventual volatiles from the film and prevents bubble formation - the vacuum was applied for 60 minutes.

[0143] The temperature was then increased to 120°C for an additional 30 minutes (still under vacuum) to more efficiently relieve residual stress in the film and avoid shrinkage during curing and cooling. For the curing cycle, the temperature was increased to 160°C and a pressure of 85 kPa was applied to the laminate using a diaphragm for 1 hour. The sample was then removed from the laminator and placed at room temperature to cool. The complete lamination cycle diagram and schematic are shown in Figures 1 and 2.

[0144] The resulting glass laminated sample was a 5 x 5 cm square, and an image of the sample after the lamination process is shown in Figure 3.

[0145] Initial optical properties (UV / Vis spectroscopy) were measured on the glass laminate samples. Before sending the samples to the UV lamp or chamber, transmittance (Shimadzu UV2600) at various wavelengths was performed to evaluate the initial optical transmittance of the thin film from wavelengths ranging from 300 nm to 1000 nm. The initial spectrum of the sample is presented in Figure 4.

[0146] Additionally, aging studies were performed in which samples were periodically (every 3-4 days) evaluated by UV-Vis spectroscopy to follow and compare the degradation kinetics. UV aging was performed under continuous irradiation of 1000 W / m 2 (Lamp: Lumixo S plasma lamp - Lumartix). Due to the heat emitted by the lamp, the sample was at an approximate temperature of 65°C. After 2000 hours, the temperature was increased to 85°C on a hot plate to accelerate decomposition.

[0147] Damp Heat Test - Accelerated degradation was performed in a climate chamber (Blue M, CEO932-4) with high temperature and moisture content (65°C, 85% RH) and exposed to UV radiation (halogen lamp). The spectra for UV aging and the damp heat climate chamber are presented in Figure 5.

[0148] For data generated in both tests (UV degradation and humidity heat), the main calculation parameter was the area of ​​the spectrum, which was numerically integrated using Microsoft Excel using the trapezoidal rule to quantify the total transmittance of the sample for all wavelengths studied. The integral of each measurement was plotted against time to understand the behavior of the sample within the entire test time frame (approximately 3000 hours).

[0149] In the UV degradation tests, indices such as the initial transmittance and the slope of the transmittance versus time that can be related to the degradation rate of the material were calculated and compared.

[0150] UV Decomposition Test - Results In Figure 6 the transmittance of all samples upon UV exposure is shown. Compared to EVA, a less steep slope can be observed for the terpolymers (DV001A and DV001B). On the other hand, SentryGlas showed a positive slope, with increasing transmittance over time. The different behavior of SentryGlas during UV exposure can be explained by the fact that it is a different substance (iomonomer). Therefore, a direct comparison in Figure 6 is made considering EVA and the terpolymer according to the present disclosure.

[0151] The terpolymer containing VeoVa™ 10 exhibited a less steep slope (angle factor)—a more gradual decrease in transmittance over time, which may be related to a slower degradation rate. This is consistent with literature observations for comparisons of vinyl acetate and larger, branched vinyl ester-based copolymers. The transmittance comparisons of the samples are plotted in Figures 7-9.

[0152] The indices (angular coefficient (m), linear coefficient (b), and initial transmittance - b0) calculated from the numerically integrated data are shown in Figures 10, 11, and 12.

[0153] Regarding initial permeability, EVATANE showed the highest value for both the measurements and their linear fits, which is in line with previous findings (membrane permeability) and theory that lower crystallinity (due to the higher mole percent of comonomer in the ethylene copolymer) results in higher permeability. However, DV001A and DV001B showed values ​​comparable to HM728. All terpolymers and EVA showed higher permeability than SentryGlas. Finally, comparison of the linear coefficients of the fits and measurements showed the same trend, with the actual measurements being very similar except for DV001A, which showed a slightly higher difference.

[0154] High Temperature and Dampness Test - Results The performance evaluation for the humid heat test was performed by considering the following parameters: i) the initial transmittance (t=0) - the transmittance before exposure to the climate chamber; ii) the plateau observed after the initial significant drop (the 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 and adjusting the linear coefficient in the fit to bring the angular coefficient as close to zero as possible. The three parameters were plotted and compared, as can be seen in Figures 13-19.

[0155] SentryGlas is a different material (ionomer) and therefore behaves differently than the other laminated samples when considering the initial permeability, however SentryGlas exhibits very similar permeability to all EVAs and terpolymers when considering their respective plateaus.

[0156] It can be seen that DV001A exhibited the highest plateau value, while EVATANE exhibited a lower value (followed closely by HM728), although the difference is not necessarily large (4.9% difference comparing DV001A and EVATANE). The DV001B response is very close to the DV001A response (0.32% lower than DV001A).

[0157] The difference between the initial transmittance and the plateau transmittance indicates how much this test affects the optical properties of the thin film. DV001A, along with both EVAs, showed the highest value (close to 9.5%). DV001B showed a difference between the initial transmittance and the plateau transmittance of approximately 7.3%.

[0158] Thus, it is clearly seen that the thin films of the present invention (especially those containing DV001A) exhibit high plateau transmittance and did not exhibit any significant difference in terms of performance loss in the test, suggesting that they have potentially competitive advantages when compared to thin films containing conventional EVA and are suitable for this application.

[0159] Example 6 Adhesion Test The same procedure (annealing, cross-linking parameters) was used to prepare samples for glass adhesion testing. Glass substrates with dimensions of 2.5 cm x 10 cm x 4 mm, a commercially available backsheet material (CPX1000 - cross-linked polyolefin-based backsheet), and an extruded film containing the above formulation were cut to suitable dimensions and laminated together. An adhesion test was performed. A schematic diagram is shown in Figure 20.

[0160] Adhesion Test - 90° peel tests using the above samples (glass / thin film / crosslinked polyolefin laminates) were carried out according to ASTM D3330 on specimens 10 cm long (9 cm including EVA adhesive) and 2.5 cm wide at a speed of 300 mm / min. Three tests were carried out for each material.

[0161] For data analysis, mean values ​​of force (N), work (N.mm), and energy (N / mm) were calculated, where work and energy were obtained using numerical integration (trapezoidal rule) with the raw force versus displacement data. All samples were compared for work and energy, and values ​​ranging from 0 mm to 85 mm were used to reduce differences across all tested lengths.

[0162] On the other hand, for the average force, more specific regions of the plot were used, obtained from consideration of the initial and end regions of the measured force and the increase and decrease in slope, in order to better represent the average value. The plots are presented in Figures 21 and 22 (scales between the plots are different), and the calculated numerical results are presented in Tables 17 to 19.

[0163] [Table 17]

[0164] [Table 18]

[0165] [Table 19]

[0166] It can be seen by all metrics that DV001A outperformed all other grades, including EVATANE 3345PV. The lowest adhesion was found with HM728. VA, VeoVa, and overall comonomer content did not directly relate to adhesion strength, nor could a relationship be discerned for contact angle (related to surface energy) and MFR (which may relate to the ability to spread and efficiently wet the substrate).

[0167] While only a few exemplary embodiments have been described in detail above, those skilled in the art will readily recognize that many modifications are possible in the exemplary embodiments without substantially departing from the present invention. Accordingly, all such modifications are intended to be included within the scope of the present disclosure, as defined by the following claims. In the claims, means-plus-function clauses are intended to cover not only the structures described herein and structural equivalents when performing the recited function, but also equivalent structures. Thus, although nails and screws may not be structurally equivalent in that nails use cylindrical surfaces to attach wooden parts together, while screws use helical surfaces in a fastening environment, nails and screws may be equivalent structures. It is applicant's express intent not to invoke 35 U.S.C. 112(f) on any limitation of the claims herein, except where the claims clearly use the term "means for" with the relevant function.

Claims

1. 1. A thin film comprising a polymer composition, The ethylene content ranges from 40% to 99.9% by weight, and the melt index (I) measured according to ASTM D1238 (190°C and 2.16 kg load) 2 ) A thin film comprising a polymer made from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate, having a viscosity of 0.1 g / 10 min to 100 g / 10 min.

2. The polymer composition comprises: cross-linking agent in an amount of 0.01 phr to 10 phr; crosslinking coagent in an amount of 0.01 phr to 5 phr; a first antioxidant in an amount of 0.01 phr to 5 phr; a second antioxidant in an amount of 0.01 phr to 5 phr; Light stabilizers in amounts of 0.01 phr to 5 phr; UV absorbers in amounts 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.

10. The thin film of claim 1, further comprising one or more of:

3. The one or more branched vinyl ester monomers have the general structure (II): 【Chemical 1】 (In the formula, R 4 and R 5 has a total of 7 carbon atoms) 3. The thin film according to claim 1, wherein

4. 4. The thin film according to any one of claims 1 to 3, wherein the polymer has a total comonomer content in the range of 10% to 60% by weight, preferably 20% to 50% by weight.

5. The polymer has a modulus of 0.8 g / cm, measured according to ASTM D792 3 ~1.3g / cm 3 Density in the range of 0.93 g / cm 3 ~0.96g / cm 3 5. The thin film according to claim 1, having a density in the range of

6. The polymer has a melt index (I) ranging from 1 g / 10 min to 100 g / 10 min, measured according to ASTM D1238 (190°C and 2.16 kg load). 2 ), preferably in the range of 5 g / 10 min to 50 g / 10 min. 2 6. The thin film according to claim 1, wherein

7. The polymer has the following properties: a melting point of less than 90°C, preferably between 60°C and 80°C, measured according to ASTM D3418; - 1×10 14 Greater than 1 x 10 ohm.cm, preferably 1 x 10 15 A volume electrical resistivity measured in accordance with ASTM D257 greater than ohm.cm; - Shore A hardness less than 90, preferably less than 80, measured according to ASTM D2240; - Vicat softening point less than 50°C measured according to ASTM D1525; - a contact angle measured according to ASTM D5946 greater than 80°; - a light transmittance, measured according to ASTM D1003, higher than 85%, preferably higher than 93%; - haze measured according to ASTM D1003 less than 10%, preferably less than 8%; - Water vapor permeability coefficient 22000μm.g / m measured according to ASTM F1249 2 .day less; - a breaking stress measured according to ASTM D638 of at least 5 MPa, preferably at least 9 MPa; - a strain at break measured according to ASTM D638 of at least 500%, preferably at least 800%; - UV cut-off wavelength 380nm, preferably 360nm; an optical transparency, measured according to ASTM D1003, of greater than 80%, preferably greater than 89%; and - Glass transition temperature below -19°C via tan δ and glass transition temperature below -29°C via loss modulus, measured by DMA, tensile fixture, tension ° / min according to ASTM D4065 7. The thin film of claim 1, wherein the thin film has one or more of the following:

8. 8. The thin film of claim 1, wherein the thin film is cross-linked.

9. 9. The film of any one of claims 1 to 8, wherein the film exhibits a gloss at 45° of at least 77%, measured according to ASTM D2457.

10. 10. The film according to any one of claims 1 to 9, wherein the film exhibits a gloss at 60° of at least 90%, measured according to ASTM D2457.

11. A method for producing a thin film according to any one of claims 1 to 10, comprising the steps of: a polymer made from ethylene, one or more branched vinyl ester monomers, and optionally vinyl acetate; and Optionally, peroxides; crosslinking coagents; primary antioxidants; secondary antioxidants; light stabilizers; UV absorbers; adhesion promoters, heat stabilizers, plasticizers, rubbers / elastomers, fillers, and combinations thereof; blending a polymer composition comprising: the blending method comprises using a twin screw extruder, a single screw extruder, a kneader, a Banbury mixer, a mixing roller, or a cast film extruder; and Manufacturing thin films with thicknesses ranging from 5 μm to 800 μm by cast film extrusion, blown film extrusion, or calendering A method comprising:

12. The method according to claim 11, wherein the membrane thickness is in the range of 50 μm to 1000 μm, preferably in the range of 400 μm to 500 μm.

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

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

15. A solar cell encapsulant comprising the thin film according to any one of claims 1 to 10.

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

17. 17. The laminate of claim 16, further comprising a backsheet comprising a polymeric substrate or a second glass substrate.

18. 17. The laminate of claim 16, having a work of adhesion according to ASTM D3330 of at least 150 N.mm.

19. UV lamp aging test (1000W / m 2 17. The laminate of claim 16, having a loss in total light transmission at 65°C (at 65°C) of less than 1%.

20. 17. The laminate of claim 16, having less than a 12% loss in total light transmission in a high temperature and humidity test (65°C, 85% relative humidity, and UV exposure).

21. A method for producing a molded article, comprising applying a thin film according to any one of claims 1 to 10 to a substrate. A method comprising:

22. 22. The method of claim 21, wherein the applying step comprises vacuum laminating the thin film to the substrate, the thin film sealing and / or bonding the photovoltaic element to the substrate.

23. 22. The method of claim 21, wherein the applying step comprises undergoing a vacuum lamination process at a pressure of 5 kPa to 200 kPa, a temperature of 130°C to 250°C, and a time frame of 1 minute to 2 hours or less to crosslink the thin film and thereby encapsulate the photovoltaic device.

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