ELECTRONIC DEVICE MODULE

Abstract

An electronic device module including a glass cover sheet, a polymeric front polymeric material, an electronic device, a polymeric back material and a backsheet, wherein the polymeric front and/or back materials have a trilayer structure including a back layer which is adhered to a surface of the electronic device, a front layer which is adhered to the glass cover sheet or the backsheet and an intermediate layer between the back layer and the front layer, wherein each of the back layer and the front layer includes an ethylene interpolymer grafted with silane, wherein the ethylene interpolymer grafted with silane has a density of at most 0.905 g/cm.sup.3, and the intermediate layer is a non-grafted ethylene interpolymer having a density of at most 0.905 g/cm.sup.3, which is crosslinked with the aid of a crosslinking initiator and optionally a crosslinking coagent, and optionally additives. A trilayer polymeric film having outer layers including ethylene interpolymers grafted with silanes and a non-grafted innerlayer containing a peroxide and UV stabilizer.

Claims

1. An electronic device module, comprising: a glass cover sheet, a polymeric front material, an electronic device, a polymeric back material and a backsheet, wherein the polymeric front and/or back materials have a trilayer structure comprising a back layer which is adhered to a surface of the electronic device, a front layer which is adhered to the glass cover sheet or the backsheet and an intermediate layer between the back layer and the front layer, wherein each of the back layer and the front layer comprises an ethylene interpolymer grafted with silane, wherein the ethylene interpolymer grafted with silane has a density of at most 0.905 g/cm.sup.3, and the intermediate layer consists of a non-grafted ethylene interpolymer having a density of at most 0.905 g/cm.sup.3, which is crosslinked with the aid of a crosslinking initiator and optionally a crosslinking coagent, a UV stabilizer and optionally one or more additives, and wherein the back layer and the front layer comprise less than 0.1 wt % of a UV stabilizer.

2. The electronic device module according to claim 1, wherein the polymeric material comprises 40-90 vol % of the intermediate layer and 10-60 vol % of the total of the back layer and the front layer.

3. The electronic device module according to claim 1, wherein the polymeric material has a thickness of 100-1000 μm.

4. The electronic device module according to claim 1, wherein the ethylene interpolymer has a 2 percent secant modulus of less than 150 MPa as measured by the procedure of ASTM D-882-02.

5. The electronic device module according to claim 1, wherein the ethylene interpolymer has a Tg of less than −35° C. as measured by differential scanning calorimetry (DSC) using the procedure of ASTM D-3418-03.

6. The electronic device module according to claim 1, wherein the crosslinking initiator is a peroxide.

7. The electronic device module according to claim 1, wherein the crosslinking coagent is triallyl cyanurate or triallyl isocyanurate.

8. The electronic device module according to claim 1, wherein the ethylene interpolymer grafted with silane of the front layer and the back layer has a melt index of 10-35 dg/min (ASTM D-1238 (190° C./2.16 kg)) before crosslinking, and wherein the intermediate layer has a melt index between 10-35 dg/min before crosslinking (ASTM D-1238 (190° C., 2.16 kg)).

9. (canceled)

10. The electronic device module according to claim 1, wherein the silane is selected from the group consisting of vinyl triethoxy silane, vinyl trimethoxy silane, (meth)acryloxy propyl trimethoxy silane and mixtures of these silanes.

11. The electronic device module according to claim 1, wherein the electronic device is a photovoltaic element.

12. A three layered polymeric film, comprising two outer layers and one intermediate layer, wherein each outer layer independently has a thickness between 5-200 μm and comprises an ethylene interpolymer, having a density 0.905 g/cm.sup.3 and a MI (190° C., 2.16 kg; ASTM D-1238) between 10-35 g/10 min, and wherein the ethylene interpolymer in each outerlayer has been grafted with 0.5-10 wt % of a silane, and wherein the outer layers comprise less than 0.1 wt % of a UV stabilizer and less than 0.05 wt % of a peroxide; wherein the intermediate layer has a thickness between 40-800 μm and comprises an ethylene interpolymer, having a density ≦0.905 g/cm.sup.3 and a MI (190° C., 2.16 kg; ASTM D-1238) between 10-35 g/10 min, wherein the ethylene interpolymer of the intermediate layer is not grafted with silane, and wherein the intermediate layer comprises between 0.05 and 10 wt % of a peroxide having a half lifetime at 110° C. of more than 1 hour and a half lifetime at 160° C. of less than 6 minutes and wherein the intermediate layer comprises between 0.1-0.8 wt % of a UV stabilizer.

13. The polymeric film according to claim 12, wherein the MI (190° C., 2.16 kg) of the layers ranges between 15-32.

14. The polymeric film according to claim 12, wherein the amount of grafted silane in the outer layers ranges between 0.7-5 wt %.

15. The polymeric film according to claim 12, wherein at least 50 wt % of the outer layers of the polymeric film consist of the silane grafted ethylene interpolymer, and wherein at least 50 wt % of the intermediate layer consists of the non-grafted ethylene interpolymer, the peroxide and UV stabilizer.

16. (canceled)

17. The polymeric film according to claim 12, wherein the silane is selected from the group consisting of vinyl trimethoxy silane, vinyl triethoxy silane, (-(meth)acryloxy propyl) trimethoxy silane and mixtures of these silanes.

18. The polymeric film according to claim 12, wherein the peroxide is selected from the group consisting of dicumyl peroxide, t-butyl cumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)-hexane, 2,5-dimethyl-2,5-di(t-amylperoxy)-hexane, di[(t-butylperoxy)-isopropyl]benzene, di-t-amyl peroxide, 1,3,5-tri-[(t-butylperoxy)-isopropyl]benzene,1,3-dimethyl-3-(t-butylperoxy)butanol, 1,3-dimethyl-3-(t-amylperoxy)butanol, 1,1-di(t-butylperoxy)cyclohexane n-butyl, 4,4-di(t-amylperoxy)valerate, 2,2-di(t-amylperoxy)propane, n-butyl-4,4-bis(t-butylperoxy)-valerate, mono-t-butyl-peroxysuccinate; mono-1-pentyl-peroxysuccinate and/or azo initiators e.g., 2,2′-azobis-(2-acetoxypropane) and mixtures of two or more of these initiators.

19. The polymeric film according to claim 12, wherein the the backlayer and frontlayer comprise less than 0.1 wt % of a UV stabilizer.

20. A process for the production of the coextruded three layer film according to claim 12, wherein the coextrusion process is operated at processing temperatures between 90 and 130° C., and at extrusion speeds of at least 2 m/min.

21. An article comprising a film according to claim 12.

22. An article prepared by applying a film according to claim 12 on a substrate, and enabling cure of the intermediate layer of the film by heating or irradiation with actinic radiation.

23. (canceled)

24. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0083] FIG. 1 shows a schematic side view of the electronic device module according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0084] FIG. 1 shows a device module having a glass cover sheet 1, which is adhered to a polymeric front material 2, an electronic device 3, a polymeric back material 4 and a backsheet 5. Electronic device 3 has a front layer which is directed to and aligned with the glass cover sheet 1 and a back layer which is directed to and aligned with the backsheet 5. At least one of the polymeric materials 2 or 4 have a trilayer structure, preferably both polymeric materials have a trilayer structure. Polymeric material 2 preferably comprises a back layer 23 which is adhered to the front surface of the electronic device 3, a front layer 21 which is adhered to the glass cover sheet 1 and an intermediate layer 22 between the back layer 23 and the front layer 21.

[0085] Polymeric material 4 preferably comprises a back layer 43 which is adhered to the back surface of the electronic device 3, a front layer 41 which is adhered the backsheet 5 and an intermediate layer 42 between the back layer 43 and the front layer 41.

TABLE-US-00001 TABLE 1 MFR (2.16 kg/ Density Concentration Type Purpose 190° C.) (kg/m3) (wt %) VLDPE1 Linear Low 28 ± 5 880 ± 5 density Polyethylene VLDPE2 Linear Low 28 ± 5 900 ± 5 density Polyethylene VLDPE3 Linear low  6 ± 2 880 ± 5 Density Polyethylene Trigonox 311 in VLDPE1 Peroxide for 10 grafting TBEC (tert-Butylperoxy 2- Peroxide for 10 ethylhexyl carbonate) in crosslinking VLDPE1 TAIC (triallyisocyanuraat) in Crosslinking 10 VLDPE1 agent Geniosil XL10 Grafted material (Vinyltrimethoxysilane) Cyasorb R350-4A UV stabilization 30 Masterminds PE black Black pigment 95/1055 Yparex VTMOS- MFR (2.16 kg/ Density materials Description content (wt %) 190° C.) (kg/m3) Yparex1 VLDPE1-g-VTMOS 3.3 ± 0.5 28 ± 5 880 ± 5 Yparex2 VLDPE3-g-VTMOS 3.3 ± 0.5  6 ± 2 880 ± 5 Yparex3 LLDPE-g-MAH 2.5 933 Yparex4 VLDPE1-g-VTMOS + 0.75% 3.3 ± 0.5 28 ± 5 880 ± 5 Cyasorb R350-4A Backsheets PV Supplier Type backsheet AAA3554 Isovoltaic PA treated-PA-PA (3 layers) TPC3480 Isovoltaic Cu-PET-PVF (3 layers) Polymeric material nr. Films Layers Thickness (μm) S1 Yparex1-VLDPE1-Yparex1 3 46 + 368 + 46 = 460 (comparative) S2 Yparex1-VLDPE2-Yparex1 3 46 + 368 + 46 = 460 (comparative) S3 Yparex1-(VLDPE1 + 2% TBEC)- 3 46 + 368 + 46 = 460 Yparex 1 S4 Yparex1- 3 46 + 368 + 46 = 460 (VLDPE1 + 1% TBEC + 0.5% TAIC)-Yparex1 S5 (comparative) Yparex1 1 230 S6 (comparative) Yparex3 1  25 S7 (comparative) DOW Enlight XUS 66232.00 1 457 S8 Yparex1- 3 46 + 368 + 46 = 460 (VLDPE1 + 1% TBEC + 0.5% TAIC + 0.75% Cyasorb R350- 4A)-Yparex1 S9 Yparex4- 3 46 + 368 + 46 = 460 (VLDPE1 + 1% TBEC + 0.5% TAIC + 0.75% Cyasorb R350- 4A)-Yparex4 S10 Yparex1- 3 46 + 368 + 46 = 460 (VLDPE1 + 1% TBEC + 0.5% TAIC + 0.75% Cyasorb R350- 4A + 1.5% Masterminds PE black 95/1055)-Yparex1

[0086] Test Methods

[0087] The Si-content was determined according to ISO12677: a polymer sample is pressed to plates with a thickness of 1.8-2 mm in a Fonteijne press using a temperature of 160° C. during 2 minutes. A Philips WDXRF PW2404 spectrometer is calibrated with suitable reference samples. Calibration data are stored in the program PE Si (quantitative). Using the program PE Si (quantitative) the sample is analyzed and the Si-content is calculated. The VTMOS content is calculated from the Si-content: VTMOS (wt %)=Si (wt %)*148.25/28.

[0088] MFR was determined according to ISO1133 at 190° C. and 2.16 kg: 4-5 gram polymer sample is introduced in the specially designed MFI apparatus. The apparatus consists of a small die inserted into the apparatus, with the diameter of the die generally being around 2 mm. The material is packed properly inside the barrel to avoid formation of air pockets. A piston is introduced which acts as the medium that causes extrusion of the molten polymer. The sample is preheated for a specified amount of time: 5 min at 190° C. After the preheating a weight of 2.16 kg is introduced onto the piston. The weight exerts a force on the molten polymer and it immediately starts flowing through the die. A sample of the melt is taken after a desired period of time and is weighed accurately. MFI is expressed as grams of polymer/10 minutes of total time of the test. Synonyms of Melt Flow Index are Melt Flow Rate and Melt Index. More commonly used are their abbreviations: MFI, MFR and MI. Confusingly, MFR may also indicate “melt flow ratio”, the ratio between two melt flow rates at different gravimetric weights. More accurately, this should be reported as FRR (flow rate ratio), or simply flow ratio. FRR is commonly used as an indication of the way in which rheological behavior is influenced by the molecular mass distribution of the material.

[0089] Density was determined according to ISO1183: the specimen is weighed in air, and subsequently weighed when immersed in distilled water at 23° C. using a sinker and wire to hold the specimen completely submerged as required. The density is calculated according to the guidelines given in the ISO method. The specimen size can be any convenient size.

[0090] Optical properties were determined according to ASTM D1003: transmission is defined as the percent of incident light that is able to pass through a material. The higher the transmission value, the more transparent a material is. Haze is defined as the percent of transmitted light that is scattered more than 2.5° from the direction of the incident beam. Materials with haze values greater than 30% are considered diffused. Testing is performed in either a Hazemeter (Procedure A) or a Spectrophotometer (Procedure B). In both cases, light passes through the test specimen on its way to a photo detector. When Hazemeter and Spectrophotometer values are not consistent, the Hazemeter values take precedence.

[0091] Peel strength measurement example 2: the peel strength was determined using the following test set-up: Machine: Zwick Z050; Control & analysis: Zwick software TestXpert II; Load-cell: 2 kN cell; Displacement: Bench displacement; Grips fixture: 10 kN manual grip; Test speed: 100 mm/min; Test conditions: 23° C. & 50% R.H. The sample is clamped on the test set-up under a 45° angle. Approximately 15 mm foil is then clamped in the grip. After the pre-load is reached the machine moves with a constant speed and peels the foil from the glass, keeping an angle around 90° (depending on the stiffness of the foil).

[0092] Peel strength measurement example 3 and 4: the peel strength was determined using a 90° peel test, based on ASTM D 6862-04. Lower linear speeds (ca. 30 mm/min) were used though, whereas linear speed proposed in the standard is 250 mm/min. A lower speed makes testing more time consuming, but provides more detailed and reliable data. 3 strips of 0.5-1 cm width (depending on peel force to be applied) were measured.

Example 1

[0093] Preparation of silane grafted very low density polyethylene (Yparex1 and Yparex2).

[0094] Two types of very low density polyethylene were grafted in an W&P ZSK40 extruder with vinyl trimethoxy silane. In the twin screw extruder the raw materials were fed to the hopper. A peroxide masterbatch (MB, 10% Trigonox 311 in VLDPE1) was also fed to the hopper. Liquid vinyl trimethoxysilane (VTMOS) was dosed by a pump to the molten polymer via a valve attached to the twin screw extruder.

[0095] Experimental Details:

Output: 57.5 kg/h
Screw speed: 430 rpm

Torque: 40%

[0096] Temperature melt: 250° C.
Temperature reaction zone: 260° C.
Temperature end reaction zone: 280° C.
Die temperature: 310° C.
Two strands 4 mm
Cooling water temperature: 7.5° C.
Peroxide MB dosed to VLDPE1: 2.2 wt %
Peroxide MB dosed to VLDPE3: 2.5 wt %
VTMOS dosed to VLDPE1: 3.85 wt %
VTMOS measured in the grafted VLDPE1 by XRF: 3.63 wt %
VTMOS dosed to VLDPE3: 4 wt %
VTMOS measured in the grafted VLDPE3 by XRF: 3.7 wt %
MFR measured for grafted VLDPE1: 25 g/10 min (190° C. 2.16 kg)
MFR measured for grafted VLDPE3: 7 g/10 min (190° C. 2.16 kg)

Example 2

[0097] One layer film production and evaluation.

[0098] Film S5 (VLDPE1 grafted with 3.6 wt % vinyl trimethoxy silane (Yparex1) according to example 1) was produced on a Dr. Collin 300 mm wide cast film line. Yparex1 was processed at 120° C. After production the film was stored in an Aluminum-lined sealed bag.

[0099] As comparative materials Film S6 (MAH grafted LLDPE (Yparex3)) and S7 (DOW Enlight) were tested. Film S6 (LLDPE grafted with MAH (Yparex 3)) was produced on a 30 cm wide cast film line. Yparex3 was processed at 200° C.

[0100] The films S5-S7 were laminated on patterned SM glass, if necessary more than one layer was used. A film thickness of 400-460 micrometer was achieved by using a Teflon-film as spacer. Samples were laminated at 150° C. during a total time of 1400 seconds. Vacuum was 0.4 bar and pressure was 30 kN.

[0101] The peel strength and optical properties were measured.

[0102] The results are shown in table 2.

TABLE-US-00002 TABLE 2 Comparative Polymeric Peel strength Optical properties Experiment Material (N/mm) Transmission % Haze % A S5 1.5 90.7 19.2 B S6 <0.1 74.1 99 C S7 1.2 88.1 76

[0103] The results in Table 2 show that the polymeric material S5 has, in comparison with the other two materials, a good peel strength and superior optical properties (high transmission and very low haze).

Example 3

[0104] Three layer coextruded film production and evaluation.

[0105] On a Dr. Collin 300 mm wide cast film line three layer films were produced with the following dimensions:

[0106] Films (S1-S4) were prepared with a first (outer) layer of 46 μm, a second (inner) layer of 368 μm and a third (outer) layer of 46 μm. The films were processed at 120° C. After production, films were stored in Aluminum-lined sealed bags. The two outer layers (1 and 3) comprise Yparex 1 prepared according to example 1. The inner layer (2) is varied.

[0107] The films were laminated between glass and a backsheet (25 minutes cycle, of which 18 minutes at 155° C.). The adhesion of the four different polymeric materials on the backsheets AAA3554 and TPC3480 was tested. Also transmission and haze of the films have been determined. The results are shown in Table 3.

TABLE-US-00003 TABLE 3 Peel strength after Peel strength thermal cycle test directly after (100 cycles −40° C. Optical lamination to 90° C.) properties Polymeric Cu PA Cu PA Trans- Ex. Material (N/cm) (N/cm) (N/cm) (N/cm) mission CE 3.1 S1 >100 >100 >100  80-100 00 CE 3.2 S2 40-60 >100 40-60 10-30 0 3.3 S3 40-80 >100 50-90  70-120 000 3.4 S4 30-50 >100 30-60 50-90 000 Transmission: 0 = bad 00 = medium 000 = good to excellent

[0108] The results in Table 3 show that all polymeric materials have a good adhesion, and especially S3 and S4 have a good to excellent transmission. Furthermore the adhesion after thermal cycle test stays on a very high level, which means that the polymeric material will be stable in the applications like photovoltaic cells.

Example 4

[0109] The adhesion of four different polymeric materials against a Cu-containing sheet was tested. The tests performed were the damp-heat test and the thermic cycle test. In the damp-heat test according to IEC 60068-2-78:2001 the polymeric materials were placed in an environment of 80° C. and 85% relative humidity (RH). The adhesion (peel strength) of the polymeric material was determined after 500 and 1000 hours in this environment.

[0110] In the thermal cycle test according to JIS C-8917 or JIS C-8938 the Cu-containing sheet with the polymeric material adhered to it was cooled to −40° C. and thereafter heated to 90° C. The adhesion (peel strength) was determined after 100 and 200 cycles. The results of these tests are given in Table 4.

TABLE-US-00004 TABLE 4 Peel Optical Mechanical Strength properties Optical stability (N/cm) Transmission properties Creep DH DH DH TC TC TC directly after Transmission (expected Ex. Sealant 0 500 1000 0 100 200 production after 5 years performance) CE 4.1 S1 100 90 Nd 100 100 Nd 00 00 Bad CE 4.2 S2 50 100 Nd 50 50 Nd 0 0 Medium 4.3 S3 60 50 Nd 60 70 Nd 000 000 Good 4.4 S4 60 75 73 60 100 60 000 000 Excellent 4.5 S8 58 21 12 58 67 71 000 000 Excellent 4.6 S9 38 9 4 38 41 35 000 000 Excellent 4.7 S10 53 17 10 53 47 44 000 000 Excellent D EVA A 50 3 2 50 2 3 000 0 E EVA C 60 20 2 60 45 50 000 0 Nd = Not determined

[0111] The results in Table 4 show that the polymeric materials S3, S4, S8 and S10 according to the invention have very good initial adhesion (DH 0 and TC 0).

[0112] The results in Table 4 show further that the polymeric materials S3, S4, S8 and S10 according to the invention show less loss of adhesion after the DH500 and DH1000 tests when compared to the polymeric materials according to comparative experiments D and E, which contain EVA as comparison polymeric material. EVA is commonly used as the standard polymeric material for solar panels.

[0113] Also the adhesion results for polymeric materials S3, S4, S8 and S10 after performance of the TC100 and TC 200 tests were better than for the polymeric materials according to comparative experiments D and E.

[0114] The polymeric materials S8 and S10 show a higher initial adhesion (DH 0) compared to polymeric material S9. The polymeric materials S8-S10 comprise a UV absorber. For polymeric material S9 the UV absorber is not only present in the intermediate layer, but also in the back layer and the front layer of the trilayer film structure. After the performance of the DH500 and DH1000 tests, the materials S8 and S10 show higher adhesion when compared to the polymeric material S9. This shows the benefits of addition of a UV absorber to only the inside layer(s) of a multilayer film structure.

[0115] The examples S3, S4, S8, S9 and S10 show superior optical properties compared to S1, S2 and both EVA samples; also the mechanical stability (creep) is good to excellent for the examples according to the present invention.