Polymer composition having improved crosslinking efficiency

Abstract

The present invention relates to a polymer composition comprising: a) an ethylene-based copolymer; b) ≥ 0.1 wt.% and ≤ 5.0 wt.%, preferably ≥ 0.1 wt% and ≤ 1.0 wt%, of a crosslinking agent; c) ≥ 0.05 wt.% and ≤ 5.0 wt.%, preferably ≥ 0.05 wt% and ≤ 0.5 wt%, of a coupling agent, preferably a silane coupling agent; d) ≥ 0.05 wt.% and ≤ 5.0 wt.%, preferably ≥ 0.05 and ≤ 1.0 wt%, of a co-agent, preferably a phosphate-moiety, isocyanurate-moiety or cyanurate-moiety containing co-agent; wherein all wt% are based on the total weight of the polymer composition; and wherein the ethylene-based copolymer has a chemical composition distribution peak having a full width at half maximum (FWHM) of ≤ 0.300 ml, preferably ≥ 0.150 and ≤ 0.300 ml; wherein the chemical composition distribution is determined by high-temperature liquid chromatography. Such polymer composition allows for high efficiency during crosslinking of the composition, such as when being applied as encapsulant in photovoltaic module applications.

Description

Polymer composition having improved crosslinking efficiency

[0001] The present invention relates to a polymer composition suitable for use in solar cell assemblies, in particular in encapsulant systems for the solar cells in such assemblies. In particular, the invention relates to polymer compositions comprising ethylene-based polymers that may be applied in such encapsulant systems, wherein such compositions exhibit improved crosslinking efficiency

[0002] The increase in use of photovoltaic systems as element of the mixture of sustainable energy generation solutions, in particular electrical energy generation systems, has given rise to a need for providing high quality, durable, and economically producible solar cell systems. As these systems typically are subject to relatively harsh climate conditions, and exposed to the elements continuously, it is important that an appropriately durable means of protection is provided for the system.

[0003] The photovoltaic elements that are the functional part of such solar cell system, in the sense of the actual generation of the electrical energy under exposure to sunlight, typically are relatively fragile elements. In order to ensure that no damage is inflicted onto these elements during manufacturing of the solar cell, the transport, installation, and ultimately its operation, protective measures such as in the form of providing an encapsulation of the cell are commonly employed. This encapsulation needs to provide appropriate adhesion to both the solar cell itself, as well as to any front cover, which may be a glass cover sheet, or a cover sheet of a polymer material, such as a thermoplastic sheet, and back protection or frame member. Furthermore, the encapsulation material needs to provide protection from moisture, air, mechanical shocks, and vibrations, and needs to provide good electrical isolation and thermal creep resistance.Moreover, there are also certain requirements relating to manufacturing of the solar cell systems that need to be dealt with, including the need for easy processing and efficient curing or crosslinking.

[0004] Such encapsulation materials typically are provided in the form of compositions of thermoplastic materials, which may be applied onto a solar cell as encapsulant, for example in the form of one or more films that jointly encapsulate the solar cell, which subsequently are subjected to certain curing or setting processes. By such curing process, the thermoplasticnature of the composition ceases to be occurring, and crosslinking between polymer molecules takes place. Such cured composition can then comply with the above-stated requirements relating to providing durable protection to the solar cell assembly.

[0005] A particularly appropriate class of thermoplastic materials for use in such encapsulation compositions are ethylene-based polymers. Ethylene-based polymers, particularly ethylenebased copolymers, are thermoplastic materials that find abundant and versatile use, and are the world’s most ubiquitous thermoplastic materials. Also for use in encapsulant solutions for solar cells, ethylene-based polymers may be a very suitable option, amongst others because of their inert nature.

[0006] However, certain needs remain over the ethylene-based polymer compositions that are described in the art. In particular, in manufacturing of the encapsulated solar cells, it is relevant that the curing or crosslinking of the encapsulant composition, which involves a thermal treatment for a certain duration, is such that the initial phase of exposure of the composition to the curing temperature, being the phase wherein the material absorbs the provided heat but remains thermoplastically mouldable, is not too short, so as to allow an appropriate window for the thermoplastic shaping to be performed; where in the other hand, the curing phase itself, being the phase wherein the crosslinking occurs, should be preferably short, to allow economic processing, defined by e.g. desirably short cycle times. Put differently, the crosslinking efficiency should be desirably high.

[0007] This can now be achieved by application of the polymer composition of the present invention, by a polymer composition comprising: a) an ethylene-based copolymer; b) > 0.1 wt.% and < 5.0 wt.%, preferably > 0.1 wt% and < 1.0 wt%, of a crosslinking agent; c) > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 wt% and < 0.5 wt%, of a coupling agent, preferably a silane coupling agent; d) > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 and < 1.0 wt%, of a co-agent, preferably a phosphate-moiety, isocyanurate-moiety or cyanurate-moiety containing co-agent; wherein all wt% are based on the total weight of the polymer composition; andwherein the ethylene-based copolymer has a chemical composition distribution peak having a full width at half maximum (FWHM) of < 0.300 ml, preferably > 0.150 and < 0.300 ml; wherein the chemical composition distribution is determined by high-temperature liquid chromatography.

[0008] Such polymer composition allows for high efficiency during crosslinking of the composition, such as when being applied as encapsulant in photovoltaic module applications.

[0009] High-temperature liquid chromatography (HT-LC) measurements for determining the chemical composition distribution may for example be conducted using a PolymerChar (Valencia, Spain) solvent gradient chromatograph equipped with a binary pump (model 1260, Agilent, Waldbronn, Germany). Sample concentrations of ~ 1.0 mg / mL (solvent 1-decanol) may be used. For dissolution, the samples may first be heated in an offline autosampler at 160 °C with shaking until dissolution. Prior to injection, the sample may be allowed a further one hour of dissolution under shaking.

[0010] The following experimental parameters may be chosen: Elution temperature: 160 °C, SGIC flow rate: 0.50 mL / min, injection loop: 100 pL, SGIC stationary phase: Hypercarb® (particle size: 5 pm, column dimensions: 100mm x 4.6 mm (L x I.D.) (Thermofisher Scientific, Dreieich, Germany)). As eluent, a 1-decanol — > TCB gradient may be used with the following program: 0 - 4 min pure 1-decanol, 4 - 34 min linear gradient from 1-decanol to TCB, 34 - 40 min pure TCB. The column may be then purged for 20 min with 1-decanol at a flow velocity of 0.5 mL / min in order to establish the original adsorption equilibrium in the column again.

[0011] Detection may be done using the evaporative light scattering detector (Agilent, United Kingdom) with the following conditions: Nebulizer (90 °C), Evaporator (95 °C), Gas flow 0.3 L / min.Data collection may be performed using the PSS software and further evaluation carried out using OriginPro software (version 2019b) (OriginLab Corporation, Northhampton, MA, USA) as well as Excel 365 (Microsoft Corporation (Redmond, WA, USA)).

[0012] It is preferred that the polymer composition comprises > 90.0 wt% of the ethylene-based copolymer, with regard to the total weight of the polymer composition, preferably > 95.0 wt%, more preferably > 98.0 wt%.

[0013] For example, the ethylene-based copolymer may comprise units derived from ethylene and comonomer units derived from 1 -butene, 1 -hexene or 1 -octene.

[0014] It is preferred that the ethylene-based copolymer comprises > 5.0 and < 40.0 wt% of comonomer units, preferably > 10.0 and < 35.0 wt%, more preferably > 15.0 and < 30.0 wt%, even more preferably > 20.0 and < 30.0 wt%, with regard to the total weight of the ethylenebased copolymer.

[0015] It is also preferred that the ethylene-based copolymer has a monomodal chemical composition distribution, wherein the chemical composition distribution is determined by high- temperature liquid chromatography.

[0016] The ethylene-based copolymer may for example have a melt mass-flow rate of > 2.0 and < 25.0 g / 10 min, preferably of > 4.0 and < 20.0 g / 10 min, more preferably of > 4.0 and < 15.0 g / 10 min, as determined in accordance with ASTM D1238 (2013) at 190°C under a load of 2.16 kg (MFR2). For example, the ethylene-based copolymer may have and MFR2 of 4.0-8.0 g / 10 min. Alternatively, the ethylene-based copolymer may have and MFR2 of 8.0-15.0 g / 10 min.

[0017] The ethylene-based copolymer may for example have a density of > 850 and < 900 kg / m3, preferably of > 860 and < 890 kg / m3, more preferably of > 865 and < 885 kg / m3, even more preferably of > 865 and < 880 kg / m3, as determined in accordance with ASTM D792 (2008).

[0018] The ethylene-based copolymer may for example have an Mw / Mnof > 2.0 and < 4.0, wherein Mwis the weight average molecular weight, and Mnis the number-average molecular weight, as determined in accordance with ASTM D6474 (2012).

[0019] The crosslinking agent may for example be selected from 2,5-dimethyl-2,5-di(t- butylperoxy)hexane, 3-di-t-butylperoxide, t-cumylperoxide, 2,5-dimethyl-2,5-di-(t- butylperoxy)hexyne, dicumylperoxide, a,a’-bis(t-butylperoxyisopropyl)benzene, n-butyl-4,4-bis(t- butylperoxy)butane, 2,2-di(t-butylperoxy)butane, 1 ,1-bis(t-butylperoxy)cyclohexane, t- amylperoxy-2-ethylhexyl carbonate ,t-butylperoxy-2-ethylhexyl carbonate, t-butylperoxy benzoate, 1 ,6-di(t-butylperoxycarbonyl)hexane, and combinations thereof, preferably from dicumylperoxid, t-amylperoxy-2-ethylhexyl carbonate and t-butylperoxy-2-ethylhexyl carbonate, more preferably from t-amylperoxy-2-ethylhexyl carbonate and t-butylperoxy-2-ethylhexyl carbonate.

[0020] It is preferred that the coupling agent comprises a silane moiety and at least one alkoxy moiety, preferably wherein the alkoxy moieties comprise 1-5 carbon atoms; preferably wherein the coupling agent comprises three alkoxy moieties comprises each comprising 1-5 carbon atoms; more preferably, wherein the coupling agent comprises a (meth)acrylate moiety.

[0021] The coupling agent may for example be selected from y-chloropropyl trimethoxysilane, vinyl trimethoxysilane, vinyl triethoxysilane, vinyl-tris-(p-methoxyphenyl)silane, y- methacryloxypropyl trimethoxysilane, p-(3,4-ethoxy-cyclohexyl)ethyl trimethoxysilane, y- glycidoxypropyl trimethoxysilane, y-mercaptopropyl trimethoxysilane, y-arninopropyl triethoxysilane, and y-arninopropyl trimethoxysilane, preferably from vinyl trimethoxysilane and Y-methacryloxypropyl trimethoxysilane, more preferably y-methacryloxypropyl trimethoxysilane.

[0022] The co-agent may for example be a compound according to formula I:R2R2 — R1 — R2 formula I wherein:• R1 is a trivalent moiety bound to each R2 moiety via a heteroatom, preferably N or O; and• each R2 is a moiety comprising a terminal vinyl unsaturation, preferably each R2 is a moiety comprising 1-10 carbon atoms, more preferably each R2 is a linear moiety; preferably wherein each R2 is the same, more preferably wherein each R2 is the same and selected from ethenyl, 2-propenyl, 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, and 7-octenyl.

[0023] The compound of formula I may for example be selected from:wherein each R3 is a moiety comprising 1-5 carbon atoms, preferably wherein each R3 is a methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl moiety, more preferably wherein each R3 is the same.

[0024] Preferably, the co-agent is selected from triallyl cyanurate, triallyl phosphate, triallyl isocyanurate, and 2,4,6-trimethyl-2,4,6-trivinyl cyclotrisilazane.

[0025] In a particular embodiment , the invention also relates to a process for preparation of a polymer composition according to the invention, comprising the steps of: • providing to a melt mixer, preferably a melt extruder, a set of ingredients comprising o the ethylene-based polymer; o > 0.1 wt.% and < 5.0 wt.%, preferably > 0.1 wt% and < 1.0 wt%, of the crosslinking agent; o > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 wt% and < 0.5 wt%, of the coupling agent, preferably a silane coupling agent; ando > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 and < 1.0 wt%, of the coagent, preferably a phosphate-moiety, isocyanurate-moiety or cyanurate- moiety containing co-agent; and• extruding the set of ingredients at a melt temperature of < 100°C, preferably > 80°C and < 100°C, to form the polymer composition.

[0026] The invention also relates to a film comprising the polymer composition.

[0027] In an embodiment, the invention also relates to a process for preparation of such film, comprising the steps of:• providing to a melt mixer, preferably a melt extruder, a set of ingredients comprising o the ethylene-based polymer; o > 0.1 wt.% and < 5.0 wt.%, preferably > 0.1 wt% and < 1.0 wt%, of the crosslinking agent; o > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 wt% and < 0.5 wt%, of the coupling agent, preferably a silane coupling agent; and o > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 and < 1.0 wt%, of the coagent, preferably a phosphate-moiety, isocyanurate-moiety or cyanurate- moiety containing co-agent;• extruding the set of ingredients at a melt temperature of < 100°C, preferably > 80°C and < 100°C, to form an extrudate; and• casting the extrudate at a temperature of < 100°C to form the film.

[0028] The invention also relates to the use of the polymer or the film the improving the crosslinking efficiency reduction during the production of a photovoltaic module.

[0029] I a further embodiment, the invention also relates to an electronic device module, preferably a photovoltaic module, comprising a film comprising the polymer composition or produced using the polymer composition.

[0030] Examples of cross-sections of photovoltaic modules that may comprise the polymer composition according to the invention in its encapsulant layer(s) are provided in figures 1 and 2, wherein (1) indicates the solar cell layer, each (2) an encapsulant layer, (3) the front protection member, and (4) the back protection member. In figure 3, an exploded view of such photovoltaic module is provided, wherein each of the references (1)-(4) indicate the same as for figures 1 and 2.

[0031] The invention will now be illustrated by the following non-limiting examples.Materials

[0032] In the examples according to the present invention, the materials as listed in the below table 1 were used to prepare polymer compositions.Table 1 : Materials

[0033] The ethylene-based polymers PE1-PE4 were analysed to identify material characteristics and properties, the results of which are provided in the table 2 below.Table 2: Properties and characteristics of the ethylene-based polymersWherein:• Density is determined in accordance with ASTM D792 (2008), expressed in kg / m3;• MFR2 is the melt mass-flow rate, as determined in accordance with ASTM D1238 (2013) at 190°C under a load of 2.16 kg, expressed in g / 10 min;• comonomer content is the wt% of polymeric units derived from the comonomer in the ethylene-based polymers, as determined using13C Nuclear Magnetic Resonance on a Bruker Avance 500 spectrometer equipped with a cryogenically cooled probe head operating at 125°C, whereby the samples were dissolved at 130°C in C2D2CI4 containing DBPC as stabiliser;• Tp,mis the peak melting temperature as determined using differential scanning calorimetry (DSC) in accordance with ASTM D3418 (2008), expressed in °C;• Tcis the crystallisation temperature as determined using differential scanning calorimetry (DSC) in accordance with ASTM D3418 (2008), expressed in °C;• Mnis the number average molecular weight, Mwis the weight average molecular weight, and Mzis the z-average molecular weight, wherein Mn, Mw, and Mzare each expressed in kg / mol, and determined in accordance with ASTM D6474 (2012);• Unsaturations is the sum of vinyl unsaturations, and vinylidene unsaturations, expressed in number of unsaturations per 100000 chain carbon atoms, and are determined by1H NMR on a Bruker Avance 500 spectrometer equipped with a cryogenically cooled probe head operating at 125°C, whereby the samples are dissolved at 130°C in C2D2CI4 containing DBPC as stabiliser.• CCD - FWHM is the full width at half maximum of the peak of the chemical composition distribution (CCD), wherein the CCD is obtained by high-temperature liquid chromatography (HT-LC).

[0034] HT-LC measurements were conducted using a PolymerChar (Valencia, Spain) solvent gradient chromatograph equipped with a binary pump (model 1260, Agilent, Waldbronn, Germany). Sample concentrations of - 1.0 mg / mL (solvent 1-decanol) were used. Fordissolution, the samples were first heated in an offline autosampler at 160 °C with shaking until dissolution. Prior to injection, the sample was allowed a further one hour of dissolution under shaking.

[0035] The following experimental parameters were chosen: Elution temperature: 160 °C, SGIC flow rate: 0.50 mL / min, injection loop: 100 pL, SGIC stationary phase: Hypercarb® (particle size: 5 pm, column dimensions: 100 x 4.6 mm (L x I.D.) (Thermofisher Scientific, Dreieich, Germany)). As eluent, a 1 -decanol — > TCB gradient was used with the following program: 0 - 4 min pure 1-decanol, 4 - 14 min linear gradient from 1-decanol to TCB, 14 - 18 min pure TCB. The column was then purged for 20 min with 1-decanol at a flow velocity of 0.5 mL / min in order to establish the original adsorption equilibrium in the column again.

[0036] Detection was done using the evaporative light scattering detector (PL-ELS 1000, Polymer Labs, U.K) with the following conditions: Nebulizer (160 °C), Evaporator (250 °C), Gas flow 1.5 L / min. Data collection was performed using the PPS software and further evaluation was carried out using OriginPro software (version 2019b) (OriginLab Corporation, Northhampton, MA, USA) as well as Excel 365 (Microsoft Corporation (Redmond, WA, USA)).

[0037] The chemical composition distribution as obtained for each of the polymers PE-1-4 is presented in figure 4.Compositions

[0038] Using the above-listed materials, the compositions according to the below formulations were produced by mixing the materials in a glass vessel, mixing in a roller mixer for 6 hours, maintaining the mixtures at room temperature for 12 hours, then melt mixing at 80°C in a Haake mixer at 50 rpm for 8 minutes.Table 3: Compositions

[0039] For each of the examples 1-4, curing trials were performed to obtain information on the crosslinking behaviour of the compositions. The compositions as obtained via the method above were subjected to curing at 145°C, for a period of 30 min in a rubber process analyser, wherein the curing properties were determined in accordance with ASTM D6601-12. This resulted in torque properties as indicated in the table 4 below:Table 4: Torque properties of compression moulded samples

[0040] The above results show that the examples using the polymer compositions of the invention demonstrate a higher torque gap as comparative compositions, reflecting a higher crosslinking efficiency.

Claims

Claims1. Polymer composition comprising: a) an ethylene-based copolymer; b) > 0.1 wt.% and < 5.0 wt.%, preferably > 0.1 wt% and < 1.0 wt%, of a crosslinking agent; c) > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 wt% and < 0.5 wt%, of a coupling agent, preferably a silane coupling agent; d) > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 and < 1.0 wt%, of a co-agent, preferably a phosphate-moiety, isocyanurate-moiety or cyanurate-moiety containing co-agent; wherein all wt% are based on the total weight of the polymer composition; and wherein the ethylene-based copolymer has a chemical composition distribution peak having a full width at half maximum (FWHM) of < 0.300 ml, preferably > 0.150 and < 0.300 ml; wherein the chemical composition distribution is determined by high-temperature liquid chromatography.

2. Polymer composition according to claim 1 , wherein the ethylene-based copolymer comprises units derived from ethylene and comonomer units derived from 1 -butene, 1- hexene or 1 -octene.

3. Polymer composition according to any one of claims 1-2, wherein the ethylene-based copolymer comprises > 5.0 and < 40.0 wt% of comonomer units, preferably > 10.0 and < 35.0 wt%, more preferably > 15.0 and < 30.0 wt%, even more preferably > 20.0 and < 30.0 wt%, with regard to the total weight of the ethylene-based copolymer; preferably wherein the ethylene-based copolymer has a monomodal chemical composition distribution, wherein the chemical composition distribution is determined by high-temperature liquid chromatography.

4. Polymer composition according to any one of claims 1-3, wherein the ethylene-based copolymer has• a melt mass-flow rate of > 2.0 and < 25.0 g / 10 min, preferably of > 4.0 and < 20.0 g / 10 min, more preferably of > 4.0 and < 15.0 g / 10 min, as determined in accordance with ASTM D1238 (2013) at 190°C under a load of 2.16 kg; and / or• a density of > 850 and < 900 kg / m3, preferably of > 860 and < 890 kg / m3, more preferably of > 865 and < 885 kg / m3, even more preferably of > 865 and < 880 kg / m3, as determined in accordance with ASTM D792 (2008); and / or• an Mw / Mn of > 2.0 and < 4.0, wherein Mwis the weight average molecular weight, and Mnis the number-average molecular weight, as determined in accordance with ASTM D6474 (2012).

5. Polymer composition according to any one of claim 1-4, wherein the crosslinking agent is selected from 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 3-di-t-butylperoxide, t- cumylperoxide, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne, dicumylperoxide, a,a’-bis(t- butylperoxyisopropyl)benzene, n-butyl-4,4-bis(t-butylperoxy)butane, 2,2-di(t- butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclohexane, t-amylperoxy-2-ethylhexyl carbonate ,t-butylperoxy-2-ethylhexyl carbonate, t-butylperoxy benzoate, 1 ,6-di(t- butylperoxycarbonyl)hexane, and combinations thereof, preferably from dicumylperoxid, t- amylperoxy-2-ethylhexyl carbonate and t-butylperoxy-2-ethylhexyl carbonate, more preferably from t-amylperoxy-2-ethylhexyl carbonate and t-butylperoxy-2-ethylhexyl carbonate.

6. Polymer composition according to any one of claims 1-5, wherein the coupling agent comprises a silane moiety and at least one alkoxy moiety, preferably wherein the alkoxy moieties comprise 1-5 carbon atoms; preferably wherein the coupling agent comprises three alkoxy moieties comprises each comprising 1-5 carbon atoms; more preferably, wherein the coupling agent comprises a (meth)acrylate moiety.

7. Polymer composition according to any one of claims 1-6, wherein the coupling agent is selected from y-chloropropyl trimethoxysilane, vinyl trimethoxysilane, vinyl triethoxysilane, vinyl-tris-(p-methoxyphenyl)silane, y-methacryloxypropyl trimethoxysilane, p-(3,4-ethoxy- cyclohexyl)ethyl trimethoxysilane, y-glycidoxypropyl trimethoxysilane, y-mercaptopropyl trimethoxysilane, y-aminopropyl triethoxysilane, and y-aminopropyl trimethoxysilane, preferably from vinyl trimethoxysilane and y-methacryloxypropyl trimethoxysilane, more preferably y-methacryloxypropyl trimethoxysilane.

8. Polymer composition according to any one of claims 1-7, wherein the co-agent is a compound according to formula I:formula I wherein:• R1 is a trivalent moiety bound to each R2 moiety via a heteroatom, preferably N or O; and• each R2 is a moiety comprising a terminal vinyl unsaturation, preferably each R2 is a moiety comprising 1-10 carbon atoms, more preferably each R2 is a linear moiety; preferably wherein each R2 is the same, more preferably wherein each R2 is the same and selected from ethenyl, 2-propenyl, 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, and 7-octenyl.

9. Polymer composition according to claim 8, wherein the compound of formula I is selected from:wherein each R3 is a moiety comprising 1-5 carbon atoms, preferably wherein each R3 is a methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl moiety, more preferably wherein each R3 is the same.

10. Polymer composition according to any one of claims 1-9, wherein the co-agent is selected from triallyl cyanurate, triallyl phosphate, triallyl isocyanurate, and 2,4,6-trimethyl-2,4,6- trivinyl cyclotrisilazane.11 . Process for preparation of a polymer composition according to any one of claims 1-10, comprising the steps of:• providing to a melt mixer, preferably a melt extruder, a set of ingredients comprising o the ethylene-based polymer; o > 0.1 wt.% and < 5.0 wt.%, preferably > 0.1 wt% and < 1.0 wt%, of the crosslinking agent; o > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 wt% and < 0.5 wt%, of the coupling agent, preferably a silane coupling agent; and o > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 and < 1.0 wt%, of the coagent, preferably a phosphate-moiety, isocyanurate-moiety or cyanurate- moiety containing co-agent; and extruding the set of ingredients at a melt temperature of < 100°C, preferably > 80°C and < 100°C, to form the polymer composition.

12. Film comprising the polymer composition according to any one of claims 1-10.

13. Process for preparation of the film of claim 12, comprising the steps of:• providing to a melt mixer, preferably a melt extruder, a set of ingredients comprising o the ethylene-based polymer; o > 0.1 wt.% and < 5.0 wt.%, preferably > 0.1 wt% and < 1.0 wt%, of the crosslinking agent; o > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 wt% and < 0.5 wt%, of the coupling agent, preferably a silane coupling agent; and o > 0.05 wt.% and < 5.0 wt.%, preferably > 0.05 and < 1.0 wt%, of the coagent, preferably a phosphate-moiety, isocyanurate-moiety or cyanurate- moiety containing co-agent;• extruding the set of ingredients at a melt temperature of < 100°C, preferably > 80°C and < 100°C, to form an extrudate; and• casting the extrudate at a temperature of < 100°C to form the film.

14. Use of the polymer composition according to any one of claims 1-10 or the film according to claim 12 for the improving the crosslinking efficiency reduction during the production of a photovoltaic module.

15. An electronic device module, preferably a photovoltaic module, comprising a film comprising the polymer composition according to any one of claims 1-10 or produced using the polymer composition according to any one of claims 1-10.

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