WO 2016/001540 PCT/FR2015/051733
.1 .
ENCAPSULANT OF A PHOTOVOLTAIC MODULE
Field of the invention
5 One subject of the invention is a photovoltaic module encapsulant based on an
ethylene/alkyl acrylate copolymer in which a crosslinking agent (peroxides or
isocyanates or any other component having a crosslinking function) is present only in
very small amounts. The present invention also relates to a photovoltaic module, or to
the use of tins encapsulant composition in such a module, comprising, besides the
10 encapsulant layer, at least one adjacent layer forming a "frontsheel" or "backsheef',
more generally these Ihree successive layers: "frontshcct", encapsulant and "backsheef.
Global warming, related to the greenhouse gases given off by fossil fuels, has led
to the development of alternative energy solutions which do not emit such gases during
the operation thereof, such as, for example, photovoltaic modules. A photovoltaic
15 module comprises a "photovoltaic cell", this cell being capable of converting light
energy into electricity.
There are many types of photovoltaic panel structures.
A conventional photovoltaic cell has been represented in figure I; this
photovoltaic cell 10 comprises individual cells 12, one individual ceil containing a
20 photovoltaic sensor 14, generally based on silicon treated in order to obtain
photoelectric properties, in contact with electron collectors 16 placed above (upper
collectors) and below (lower collectors) the photovoltaic sensor. The upper collectors
16 of an individual cell are connected to the lower collectors 16 of another individual
cell 12 via conducting bars 18, generally consisting of an alloy of metals. All these
25 individual cells 12 are connected to one .another, in scries and/or in parallel, in order to
form (he photovoltaic cell 10. When the photovoltaic cell 10 is placed under a light
source, it delivers a direct electric current which can be recovered at the terminals 19 of
the cell 10.
With reference to figure 2, the photovoltaic module 20 comprises the photovoltaic
30 cell 10 of figure 1 encased in an "encapsulant", the latter being composed of an upper
part 22 and of a lower pari 23. An upper protective layer 24 (known under I lie term
"frontsheel", used hereinafter) and a layer which protects the back of the module
WO 2016/001540 PCT/FR2015/051733
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(known under the term "backsheet", also used hereinafter) 26 are positioned on either
side of the encapsulated cell.
Impact and moisture protection of the photovoltaic cell 10 is provided by the
upper protective layer 24, generally made of glass.
5 The backsheet 26, for example a multilayer film based on fluoropolymer and on
polyethylene terephthalate, contributes to the moisture protection of the photovoltaic
module 20 and to the electrical insulation of the individual cells 12 in order to prevent
any contact with the external environment.
The encapsulant 22 must perfectly adopt the shape of the space existing between
10 the photovoltaic cell 10 and the protective layers 24 and 26 in order to avoid the
presence of air, which would liniit the efficiency of the photovoltaic module. The
encapsulant 22 must also prevent contact of the individual cells 12 with atmospheric
oxygen and water, in order to limit the.corrosion thereof. The upper portion of the
encapsulant 22 is between the cell 10 and the upper protective layer 24. The lower
15 portion of the encapsulant 22 is between the cell 10 and the backsheet 26.
In the presence of solar radiation, heating occurs inside the solar module and
temperatures of 80°C (or more) may be reached, which necessitates that the layers be
perfectly bonded to one another throughout the life cycle of the module.
20, Trior art •
Currently, the majority of .the photovoltaic encapsulation market corresponds to
formulations based on an liVA to which a peroxide, a silane and various functional
additives are added.
. EVA exhibits many qualities and properties advantageous for this application.
25 This is because it confers mainly very good properties of transparency, of mechanical
strength and of resistance to aging and generally excellent thermomechanical and
mechanical properties. Furthermore, this thermoplastic is relatively inexpensive, so that
its use for this application has become virtually inescapable.
•Nevertheless, the type of encapsulant based on EVA,, with peroxide and silane,
30 has one major disadvantage.
Specifically, when the environmental conditions have deteriorated, that is to say
when the EVA encapsulant ages under hot and damp conditions (DHT (damp heat test):
85°C/85% RH (relative humidity)), this component is subject to hydrolysis winch
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brings about the appearance of acetic acid, a source of yellowing of the encapsnlant and
of corrosion of the metal connections of the photovoltaic module.
A person skilled in the art might envisage the replacement of the EVA by an
ethylene/alkyl acrylate copolymer but this solution, although admittedly avoiding the
5 specific problems related to EVA when the latter is present in a difficult environment,
does not make it possible to obtain a correct photovoltaic module. This is because,
during the lamination, numerous bubbles are formed during the crosslinking due to the
peroxide, present in significant amounts.
Furthermore, document WO 2006/095911 provides a solution by the use of a
10 formulation based on an ethylene/alkyl acrylate copolymer, the melting point of which
(T in °C), obtained according to the standard JIS K 7121, would .correspond to the
following formula: -3.0X+125 > T >-3.0X+109, the component X representing the
molar content of the polar compnomer (acrylate). Fuilhermore, this document provides
for the combining of this copolymer with a silane in order to introduce the adhesive
15 properties on the glass.
However, such a formulation would not make it possible to obtain an encapsnlant .which.
is effective over the long term. This is because the silane exhibits the disadvantage of
not making possible a good level of adhesion to the glass whcn.it. is not chemically
bonded to the polymer.
Thus, an encapsulation solution based on an alternative component to EVA but
exhibiting properties which are just as advantageous, while eliminating the risk of
giving off acetic acid, is currently being sought.
This solution should furthermore enable the use"of silane, making possible in
25 particular the attachment to the walls of the frontsheet, that is to say to a component
made of glass-ceramic or synthetic glass (conventionally PMMA).
Brief description of the invention
• .'.••• It has been found, by the applicant company, after various experiments, that a
30 composition based on an ethylene/alkyl acrylate copotymer and on silane could, with a
very low content of crosslinking agent(s), exhibit highly satisfactory thermomechanical
properties and physicochemical characteristics,
WO 2016/001540
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PCT/FR2015/051733
Thus, the present invention relates to a photovoltaic module encapsulant
intended to encase a photovoltaic cell, comprising:
- an ethylene/alkyl acrylate copolymer, the melt flow index, MFI, of said
5 copolymer being between 1 g/10 min and 40 g/10 min;
- a silane, representing between 0.1% and 0.5% of the weight of said composition;
characterized in that it additionally comprises a crosslinking agent representing
between 0.1% and 0.5% of the weight of the composition and in that said copolymer
represents at least 99% of the weight of said composition.
10
The applicant company has in fact discovered that there was a very specific
advantage in carrying out an "incomplete crosslinking". The crosslinking agent,
preferably selected from the monoperoxycarbonatc family and more specifically
consisting of Luperox® TBF.C or (OO-tert-butyl 0(2-cthylhexyl)
15 monoperoxycarbonate), present in a very small amount, enables, the .grafting of .the
silane to the copolymer and sufficiently crosslinks the latter in order to render it creep
resistant without having to achieve a significant .gel level. This..very small content of
peroxide avoids any problem of appearance of bubbles in the.lamination step.
This "incomplete crosslinking" has the advantage of being able to be carried out
20 in the lamination step, as carried out currently, but also starting from the extrusion of
the encapsulant film thus then enabling a faster lamination.
The composition according to the invention first exhibits the following
'..'•. .advantages: •"•'•'
25 - the impossibility of the appearance of acetic acid, more generally of any acid,
during its use, whatever the environmental conditions;
- the maintenance of excellent adhesive properties of the composition throughout
the lifetime of the composition, in particular in its use as encapsulant of a photovoltaic
module; '-...-
30 - improving the optical properties during aging in a difficult environment;
- the maintenance of excellent thermomechanical properties and of
physicochemical characteristics, at least as satisfactory as the current solution based on
EVA (crosslinking agent and silane).
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PCT/FR2015/051733
Other characteristics and distinctive features of the primary mixture of the
invention are presented below:
- advantageously, the crosslinking agent belongs to the monoperoxycarbonate family,
5 preferably consists of OO-tert-butyl 0-(2-ethylhexyl) monoperoxycarbonate;
- preferably, for the abovesaid copolymer, the weight content of ethylene is between
50% and 85%, preferably between 60% and 84%, and the weight content of alkyl
acrylate is between 15% and 50%, preferably between 16% and 40%;
- advantageously, the silane consists of a vinyl silane or (meth)acrylic siianes;
10 - according to a nonlmiiting specification of the invention, the silane consists of
methacryloxypropylsilane;
- advantageously, the crosslinking agent represents less than 0.3% of the weight of the
composition;
- preferably the above said copolymer has a melt flow index, Ml'l, between 2 g/10 mill
15 and lOg/lOmin; - according to one possibility offered by the invention, the composition consists solely
of the abovesaid copolymer, the abovesaid crosslinking agent and the abovesaid silane;
- according to another possibility offered by the invention, the composition additionally
comprises additives intended to confer additional specific properties, in particular
20 plastici/.crs, adhesion promoters, UV stabilizers and absorbers, antioxidants, (lame
rctardants and/or fillers.
The invention also relates to the use of the encapsulant as described above in a
photovoltaic module.
25 Finally, the invention relates to a photovoltaic module comprising a structure
consisting of a combination of at least one encapsulant and a frontsheet or backsheet,
characterized in that the encapsulant is as described above.
Description of the appended figures
30
The description which follows is given solely by way of illustration and without
implied limitation with reference to the appended figures, in which:
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figure 1, which is already described, represents an example of a photovoltaic cell,
the portions (a) and (b) being 3A views, the portion (a) showing an individual cell before
connection and the portion (b) a view after connection of 2 individual cells; the portion
(c) is a top view of a complete photovoltaic cell.
5 Figure 2, which is already described, represents a cross section of a photovoltaic
module, the "conventional" photovoltaic sensor of which is encapsulated by an upper
encapsulant film and a lower encapsulant film.
Detailed description of the invention
As regards the ethylene/alkyl acrylate copolymer, it is a component well known to
a person skilled in the art. The distinctive features specific to this copolymer, within the
context of the present invention, essentially originate from the weight proportions of
ethylene and of alkyl acrylate and from the melt flow index, MFI, of the copolymer,
15 expressed in grams per 10 minutes and measured at 19Q°C under a load of 2.16 kg.
The weight content of ethylene being between 50% and 85%, preferably between
60% and 84%, and the weight content of alkyl acrylate is between 15% and 50%,
:: preferably between 16% and 40%; •':;.••;.;
The melt flow index (MFI) of the copolymer being between 1 g/10 min and 40
20 ; g/10 min, preferably between 2 g/10 min and 10 g/10 min.
As nonlimiting example, the applicant company makes use commercially of a
component known as LOTRYL®, which is an ethylene/alkyl acrylate copolymer.
A person skilled in the art fully knows how to produce/manufacture such a
copolymer, according to the different amounts of each of the two monomers.
25 Hereinafter, the invention is presented with an ethylene/alkyl acrylate copolymer of
specific type but it has been demonstrated by the proprietor that the encapsulant
composition according to the invention meets the objectives set when the copolymer
varies within the ranges of content of ethylene and of alkyl acrylate which are defined
above, possibly in a slightly better way when said copolymer has contents of ethylene
WO 2016/001540 PCT/FR2015/051733
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and of alkyl acrylate which are chosen within the ranges preferred for these two
monomers.
As regards the silane, these are chemical compounds which make possible the
adhesion interactions between the encapsulate and the glass. As examples of silane,
5 mention may he made of 3-(trimethoxysilyl)propyl methacrylate, vinyltrimethoxysilane
or any other silane bearing a function that is reactive with respect to a peroxide-type
crosslinking agent. Preferably, the silane in the composition according to the invention
is 3-(trimethoxysilyl)propyl methacrylate. Nevertheless, equivalent or substantially
equivalent results would be obtained by choosing another silane from the family of
10 vinylsllanes or (meth)acrylic silanes.
Regarding the crosslinking agent, this element, which decomposes to initiate and
propagate chemical reactions (wilh Ihe silane for the grafting of the latter to the
copolymer chains) and crosslinking reactions (of the copolymer), is well known to a
person skilled in the art and it docs not present any ..difficulties, for its
15 manufacture/preparation.
It should be noted here that a particular family of crosslinking agents.corresponds
best to the objectives set within Ihe context qf the present patent application: these are
monopcroxycarbonatcs, and among these in particular OO-lerl-butyl 0-(2-ethylhcxyl)
monopcroxycarbonatc which is sold especially by the applicant company under the
20 ttademark Luperox® TBEC.
The composition forming the encapsulanl according to the invention could
optionally comprise a certain number of additives intended to confer additional specific
properties.
25 Plasticizers could be added in order to facilitate the processing and to improve the
productivity of the process for. the manufacture of the composition and of the structures.
Mention will be made, as examples, of paraffinic, aromatic or naphthalenic mineral oils,
which also make it possible to improve the adhesiveness of the composition according
to the invention. Mention may also be made, as plasticizer, of phthalates, azelates,
30 adipates or tricresyl phosphate.
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Adhesion promoters, although not necessary, may advantageously be added in
order to improve the adhesiveness of the composition when the adhesiveness has to be
particularly high. The adhesion promoter is a nonpolymeric ingredient; it may be
organic, crystalline, inorganic and more preferably semi-inorganic semi-organic.
5 Mention may be made, among these, of titanates,
In this specific application of the composition with photovoltaic modules, as UV
radiation is capable of resulting in a slight yellowing of the composition used as
encapsulate of said modules, UV stabilizers and UV absorbers, such as benzotriazole,
benzophenone and other hindered amines, may be added in order to ensure the
10 transparency of the encapsulanl during its lifetime. These compounds may, for example,
be based on benzophenone or on benzotriazole. They may be added in amounts of less
than 10% by weight of the total weight of the composition and preferably from 0.05%
.to 3%.
It will also be possible to add antioxidants in order to limit the yellowing dining
15 the : manufacturing of the encapsulate, such as phosphorus-based compounds
(phosphoniles and/or phosphites) and hindered phenolic compounds. These antioxidants
may be added in amounts of less than 10% by weight of the total weight of the
composition and preferably from 0.05% to 3%.
Flame retardants may also be added. These retardants may be balogenated or
20 nonhalogenaled. Among Ihe balogenated retardants, mention may be made of
brominated producls. Use may also be made, as noiilialogenated ictardant, of
phosphorus-based additives, such as ammonium phosphate, polyphosphate, phosphinate
or pyrophosphate, mclaminc cyatiuratc, pcntacrythritol, zeolites and Ihe mixtures of
these retardants. The composition may comprise these retardants in proportions ranging
2b from 3% to 40%, with respect to the total weight of the composition.
It is also possible to add pigments, such as, for example, titanium dioxide, dyeing
compounds or brightening compounds in proportions generally ranging from 5% to
15%, with respect to the total weight of the composition.
Fillers, in particular inorganic fillers, may also be added to improve the
30 thermomechanical strength of the composition. Examples which will be given are,
without implied limitation, silica, alumina or calcium carbonates or carbon nanotubes or
i
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aiso glass libers. Use may also be made of modified or nonmodified clays which are
mixed at the nanoscale; this makes it possible to obtain a more transparent composition.
Crosslinking/preparation of the encapsulant and production of an encapsulant film
5 according to the invention (intended to be incorporated in a photovoltaic module):
Conventionally, a crosslinking is necessary in order to adjust the
thermomechanical properties of the EVA-based encapsulant, in particular when the
temperature becomes very high. In this particular case, within the context of the present
invention, the crosslinking is not complete owing to a very low content of crosslinking
10 agent(s), but allows the grafting of the silanc to the copolymer chains and a partial
crosslinking of this copolymer.
The other elements of the composition, namely the silane and optionally the
fillers, are added to the crosslinking agent and to the aforesaid copolymer in a
conventional manner, well known to a person skilled in the art.
15 With regard to the aspects targeted above, the handbook entitled "Handbook of
Polymer Foams and Technology", in particular on pages 198 to 204, provides additional
instructions to which a person skilled in the art may refer.
A.s regards the aspects of the invention relating to the use of the thermoplastic
composition in a photovoltaic module, a person skilled in the art may refer, for example,
20 to the "Handbook of Photovoltaic Science and Engineering", Wiley, 2003. This is
because the composition of the invention can be used as encapsulant or encapsulantbacksheet
in a photovoltaic module, the structure of which is described in connection
with the appended figures.
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Materials employed in order to form the test formulations:
Lotryl® 17BA07: ethylene/butyl acrylate copolymer, the acrylate content of which
is 17% by weight of the copolymer and the MFI of which is 7 g/10 min (190°C, 2.13
kg). It is obtained according to an autoclave process and its melting point is 89°C.
5 In the tables of results presented below, this Lotryl® is denoted by the initials 17BA07.
Lotryl® 20MA08; ethylene/methyl acrylate copolymer, the acrylate content of
which is 20% by weight of the copolymer and the MFI of which is 8 g/10 min (190°C,
2.13 kg). It is obtained according to an autoclave process and its melting point is 75°C.
10 In the tables of results presented below, this Lotryl® is denoted by the initials 20MA08.
Lotryl® 35BA40: elhylene/bulyl acrylate copolymer, Ihe .acrylate content of which
is 35% by weight of the copolymer and the MFI of which is 40 g/K) min (190°C, 2.13
kg). It is obtained according to an autoclave process and its melting point is 66°C.
15 In the tables of results presented below, this Lotryl® i.s denoted by the initials 35BA40.
Lotryl® 35BA320: ethylene/butyl acrylate copolymer, the acrylate content of
which is 35% by weight of the copolymer and the MFI of which i.s 320 g/10 min
(190°C, 2.13 kg). It is obtained according lo an autoclave process and its melting point
2 0 / is65°C.
In the tables of results presented below, this Lotryl® is denoted by the initials 35BA320.
Lotryl* 28MA07; ethylene/methyl acrylate copolymer, the acrylate content of
which is 28% by weight of the copolymer and the MFI of which is 7 g/10 min (190°C,
25 2.13 kg). It is obtained according to an autoclave process and its melting point is 68°C.
In the tables of results presented below, this Lotryl® is denoted by the initials 28MA07.
Lotryl® 7BA01: ethylene/butyl acrylate copolymer, the acrylate content of which
is 7% by weight of the copolymer and the MFI of which is I g/10 min (190°C, 2.13 kg).
30 It is obtained according to an autoclave process and its melting point is 105°C.
In the tables of results presented below, this Lotryl® is denoted by the initials 7BA01.
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Evatane® 3345PV: ethylene/vinyl acetate copolymer, the acetate content of
which is 33% by weight of the copolymer and the MFI of which is 45 g/10 min (190°C,
2,13 kg). In the tables of results presented below, this Evatane is denoted by the initials
3345PV.
5
Dynasyian MEMO: 3-MethacryloyloxypropylTrimethoxySilane sold by Evonik.
In the tables of results presented below, this silane is denoted by the initials MTS.
Luperox® TBEC: 00-tert-butyl 0-(2-ethylliexyl) monoperoxycarbonate sold by
10 the applicant company Arkema, denoted hereinafter by TBEC.
Luperox®.101; 2,5-dimemyl-2,5 Illuminant: C
• Angle: 2°
i
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H Measurement opening: LAV 25 mm (millimeters)
• Background: "Cera" white plate + light well
Two pieces of numerical data are taken from this measurement:
5 • Haze: the haze corresponds to the degree of haze of the structure studied. It
is calculated according to the standard ASTM D-1003-007)
• Transparency: the degree of transparency is calculated by taking the mean
transmittance value between 400 and 740 nm, corrected by respective
contributions of the glass layers and of the glass/air and glass/encapsulant
10 interfaces, then standardized to a thickness of 200 um. The transparency
was also evaluated during DHT (damp heat test — 85°C / 85% relative
V; humidity/2000 h ) aging. ^
hi order to meet the requirements of the invention, the transparency test should display a
15 result above 96% and the haze test a result below 20.
Creep test: .•'•••...
..'•'.''The creep test is carried out on glass/encapsulant/glass structures (with glass sheets
haying a length L = 70 mm). After lamination, the test modules arc placed on a metal
20 structure forming an angle of 70° with the horizontal, liach module is held back by an
edge covering a portion of the thickness of the first glass layer.
This structure is placed at 100°C in an oven. Under the weight of the second glass layer,
creep may be observed. The creep value measured is thus the distance traveled by the
second glass sheet after 500 hours under these conditions. This distance is between 0
25 mm (no creep) and 70 mm (complete creep, separation of the structure).
In order to meet the requirements of the invention, the creep measurement should
display a result of less than 4 mm.
Adhesion test on a glass layer:
30 The degree of adhesion between the encapsulant and the glass is measured on
glass/encapsulant/backsheet stiuctures using a 90° peel test carried out at 50 mm/min
(millimeters per minute) on a Zwi.ck 1445 universal testing machine. The backsheet
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used for this measurement is a monolayer consisting of Apolhya® manufactured and
sold by the applicant company. The measurement conditions are as follows:
• Rate of displacement of the crosspiece: 50 mm/min
• Test specimen cut-out width: 10 mm
5 • Peel angle: 90°
The adhesion result is expressed in N/mm.
In order to meet the requirements of the invention, the adhesion measurement should
display a result of greater than 3.5 N/mm.
10 Tests on the encapsulanl were also carried out in order to confirm that this novel
structure retains excellent properties, that is to say identical properties, relative to the
properties of an encapsulanl in accordance with that described in the document WO
09138679, namely in particular relating to its mechanical, thernionicchanical and fire
rctardant properties and its electrical insulation properties. These tests proved to be
15 • '.positive. .'
The yellowing properties of the encapsulanl, formulated as described in the
present invention, wrcrc evaluated during DHT (damp heal lest - 85°C / 85% relative
humidity/2000 h) aging. The results obtained proved to be better than those obtained for
a formulation according lo the prior art.
20 'flic compositions according to the invention thus meet the criteria lo be able to be
very advantageously used as binder or encapsulanl in solar modules.
25
Results of the tests carried out on the test specimens of the different
formulations:
Compositions
Adhesion
(N/mm)
Opt. Tratismittance Prop.
to
%T. 400JI
Haze
DHT 2000
h
%T. 400(i
Creep 707110°C
(min/70 mm - 500 h)
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PCT/FR2015/051733
El
E2
E3
E4
CEl*
CE2
CE3
CE4
CE5
6.7
3.8
6.2
4.6
6.2*
0.9
3.5
4.2
99.5
94
98
99.7
99.6*
97.6
999.6
1.5
15
3
0.9
I*
3.5
25
0.9
98
93.8
97.6
99.2
93.5
97
89.8
99.3
2.5
1.5
2
3.5
0*
70
1
12
No measurement performed, presence of a very large quantity of
bubbles in the cncapsulant layer
* The results obtained on the CEl test specimen (formulation according to the prior
art) are good, but the formation of acetic acid during the DHT aging is detected and
5 gives rise to an intense yellowing of this encapsulant.
This phenomenon is not observed on any of the samples produced according to the
present invention.
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CLAIMS
1. An encapsulant (22) of a photovoltaic module (20), intended to encase a
photovoltaic cell (10), comprising:
- an ethylcne/alkyl acrylate copolymer, the melt flow index, MFI, of said
copolymer being between 1 g/10 min and 40 g/10 min;
- a silane, representing between 0.1% and 0.5% of the weight of said
composition;
characterized in that it additionally comprises a crosslinking agent
representing between 0.1% and 0.5% of the weight of the .composition and in that said
copolymer represents at least 99% of the weight of said composition.
2. The encapsulant (22) as claimed in claim 1, characterized in that the
crosslinking agent belongs to the monoperoxycarbonale ianiily, preferably consists of
OO-tcrt-butyi 0-(2-cthylhcxyI) moimpcroxycarbonate.
3. The encapsulant (22) as claimed in claim l.or.2, characterized in (hat, for
the abovesaid copolymer, the weight content of ethylene is between 50% and 85%,
preferably between 60% and 84%, and the weight content of alkyl acrylatc is between
15% and 50%, preferably between 16% and 40%.
4. The encapsulant (22) as claimed in any one of the preceding claims,
characterized in that the silane consists of a vinyl silane or (mcth)acrylic si lanes.
5. The encapsulant (22) as claimed in claim 4, characterized in that the silane
consists of 3-(trimethoxysilyl)propyl methacrylate.
6. The encapsulant (2.2) as claimed in any one of the preceding claims,
characterized in that the crosslinking agent represents less than 0.3% of the weight of
the composition.
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,7. The encapsulant (22) as claimed in any one of the preceding claims,
characterized in that the abovesaid cojfotymer has a melt flow index, MFI, between 2
g/10 min and 10 g/10 min.
8. The encapsulant (22) as claimed in any one of the preceding claims,
characterized in that the composition consists solely of the abovesaid copolymer, the
abovesaid crosslinking agent and the abovesaid silane.
9. The encapsulant (22) as claimed in any one of claims 1 lo 7,
characterized in that the composition additionally comprises additives intended to
confer additional specific properties, in particular plaslicizers, adhesion promoters, UV
stabilizers and absorbers, antioxidants, (lame retardants and/or fillers. .
10. The use of the encapsulant (22) as claimed in any one of the preceding
claims in a photovoltaic module (20). ; •.:
11.; A photovoltaic module (20) comprismg a structure consisting of a
combination of at least one encapsulant (22) and a fronlsheet (24) or a backshect (26),
characterized in that the encapsulant (22) is as claimed in any one of the preceding
claims. ;•'•'•'