Photopolymerisable adhesive composition for encapsulating electronic or optoelectronic devices

Abstract

The invention relates to a photopolymerisable adhesive composition comprising, by weight with respect to the total weight of the photopolymerisable adhesive composition, from 20% to 35% of at least one block copolymer, preferably a (meth)acrylic block copolymer; from 45% to 75% of a mixture P of (meth)acrylate monomers, wherein the homopolymer obtained after polymerisation has a glass transition temperature (Tg) of at least 85°C, the mixture P comprising at least one methacrylate monomer, wherein the homopolymer obtained after polymerisation has a glass transition temperature (Tg) of at least 85°C and at least 5% by weight of a monoacrylate monomer, wherein the homopolymer obtained after polymerisation has a glass transition temperature (Tg) of at least 85°C; from 2% to 15% of at least one (meth)acrylate alkoxysilane monomer; and from 0.1% to 5% of at least one photoinitiator.

Description

[0001] PHOTOPOLYMERIZABLE ADHESIVE COMPOSITION FOR ENCAPSULATING ELECTRONIC OR OPTOELECTRONIC DEVICES

[0002] Field of invention

[0003] The present invention relates to adhesive photopolymerizable compositions for use in encapsulating electronic and optoelectronic devices, particularly flexible electronic and optoelectronic devices, for example organic and perovskite photovoltaic cells, to protect them against gas and moisture permeation.

[0004] Technical background

[0005] There are different types of electronic or optoelectronic devices, including rigid or flexible electronic or optoelectronic devices. Rigid electronic or optoelectronic devices can be of different natures depending on the applications considered, such as display applications (e.g. OLEDs and QLEDs), photovoltaics (e.g. silicon-based semiconductors, CIGS, CDTE, organic semiconductors, Perovskite-type semiconductors) or sensors.

[0006] Flexible electronic or optoelectronic devices can be defined according to the same application examples but for semiconductor technologies compatible with the use of flexible substrates such as organic light-emitting diode (OLED) devices, organic photovoltaic (OPV) cells, amorphous silicon (a-Si) cells, CIGS, perovskite semiconductors, organic transistors (OFET) or organic sensors using organic semiconductors.

[0007] Electronic or optoelectronic devices are sensitive to multiple factors, for example light, heat, oxygen (air), humidity, pressure, shocks, etc. In order to ensure optimal efficiency and performance and to obtain satisfactory durability, it is therefore necessary to protect and isolate them from their environment. This protection must be all the more effective as the constituent materials are sensitive to the atmosphere, in particular to water and oxygen. This is particularly the case when using organic semiconductors, for example organic, perovskite or CIGS semiconductors.

[0008] Various encapsulation techniques have been implemented. These generally include coating the device with an adhesive composition to obtain a coated device, then laminating the coated device between two caps to obtain an encapsulated device. The choice of adhesive composition and caps will depend on the devices to be encapsulated. In addition, depending on the composition and caps used, the electronic or optoelectronic modules obtained will have specific properties, in particular in terms of weight, thickness, transparency / opacity, rigidity / flexibility, gas and liquid permeation / tightness, impact resistance and / or durability / aging.

[0009] Considering the layered arrangement, two types of permeation can be observed, an orthogonal permeation at the external surface of the covers between which the coated devices are interposed, and a lateral permeation at the free edge of the adhesive within the coating material as well as at the interface of the two covers.

[0010] The protection of the device against lateral permeation is ensured in particular by the adhesive or coating material, the effectiveness of which may depend on various factors, in particular its chemical formulation, its application process, its thickness (proportional to the exchange surface with the environment), its interface with the covers, its resistance to usage constraints, etc. The properties of the adhesive must therefore be optimized to minimize or even eliminate the lateral permeation of gases from the atmosphere (in particular water vapor and oxygen), to ensure optimal efficiency and performance and to obtain satisfactory durability.

[0011] Flexible photovoltaic cells (e.g. organic, perovskite, CIGS, CDTE) represent a particularly attractive alternative to rigid silicon-based photovoltaic cells, as they can be manufactured using continuous, high-speed processes (roll-to-roll) and can be suitable for applications requiring flexibility, conformability, or low weight. They are also less fragile (use of flexible covers) and less susceptible to breakage.

[0012] Flexible photovoltaic cells can for example be obtained by low temperature printing of a thin active layer (organic material or perovskite having semiconducting properties) deposited on a flexible polymeric support substrate. The encapsulation of a flexible electronic or optoelectronic device can be carried out by means of a cover with low permeability to gases, in particular to water vapor and oxygen, which must be at least as flexible as the device it protects so as not to become a factor limiting the bending of the latter, or it must have controlled flexibility when, for example, encapsulation is used to knowingly limit the radius of curvature of the device and to avoid its damage.

[0013] There is therefore a real need to provide an adhesive composition allowing the production of electronic or optoelectronic modules having satisfactory properties, in particular satisfactory adhesive, optical, thermal, electrical, gas barrier, elastic and resistance properties. There is also the need to provide an adhesive composition suitable for the encapsulation of flexible electronic or optoelectronic devices. There is also the need to provide an adhesive composition allowing the production of electronic or optoelectronic modules exhibiting photo-aging (for example yellowing) limited over time. There is also the need to provide an adhesive composition allowing the production of electronic or optoelectronic modules exhibiting lateral permeation to gases and water limited over time.There is also a need to provide an adhesive composition that allows the production of electronic or optoelectronic modules that ensure optimum efficiency and performance and have satisfactory durability. Finally, there is an interest in providing such an adhesive composition with rapid polymerization and a high monomer-to-polymer conversion rate.

[0014] Summary of the invention

[0015] The present application relates firstly to a photopolymerizable adhesive composition comprising, by weight per total weight of the photopolymerizable adhesive composition: from 20 to 35% of at least one block copolymer, preferably a (meth)acrylic block copolymer; from 45 to 75% of a mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C, said mixture P comprising at least one methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C and at least 5% by weight of a mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C; from 2 to 15% of at least one alkoxysilane (meth)acrylate monomer; and from 0.1 to 5% of at least one photoinitiator.

[0016] Preferably, the block copolymer is chosen from the group consisting of block copolymers comprising at least one block M and at least one block B; said block M designating a polymer block comprising at least 50% by weight of methyl methacrylate; and block B designating an elastomeric polymer block incompatible with block M, and whose glass transition temperature (Tg) is less than 20°C.

[0017] In one embodiment, the mixture P comprises at least one methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C chosen from the group consisting of methyl methacrylate, tert-butyl methacrylate, phenyl methacrylate, isopropyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, and mixtures thereof, preferably the methacrylate monomer is methyl methacrylate;and at least 5% by weight relative to the total weight of the mixture P of a mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C chosen from isobornyl acrylate, dihydrodicyclopentadienyl acrylate, and mixtures thereof, preferably the acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C is isobornyl acrylate.;

[0018] In one embodiment, the mixture P further comprises at least one diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C, preferably said diacrylate monomer is chosen from dipropylene glycol diacrylate, neopentyl glycol hydroxypivalate diacrylate, tricyclodecanedimethanol diacrylate, preferably the diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C is tricyclodecanedimethanol diacrylate (TCDDMDA).

[0019] Preferably, the mixture P comprises:

[0020] - from 20% to 95% by weight, more preferably from 20% to 80% by weight, and even more preferably from 30% to 70%, preferably from 40 to 60%, by weight relative to the weight of mixture P, of at least one methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C; - at least 5%, preferably at least 10%, more preferably from 5 to 80%, more preferably from 20% to 80% even more preferably from 30% to 70%, preferably from 40 to 60% by weight of a mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C; and from 1 to 20% by weight, more preferably from 1 to 10% by weight, preferably from 1 to 5% by weight, of at least one diacrylate monomer of which the homopolymer obtained after polymerization has a glass transition temperature of at least 85°C.

[0021] In one embodiment, the alkoxysilane (meth)acrylate monomer is selected from the group consisting of trialkoxysilane (meth)acrylate monomers.

[0022] Preferably, the composition according to the invention comprises, preferably consists of, by weight per total weight of the composition: from 25 to 35%, preferably from 28 to 32%, of at least one block copolymer;from 45 to 65%, of a mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, said mixture P comprising from 40 to 60% by weight of a methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, preferably methyl methacrylate, and from 40 to 60% by weight of a mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, preferably isobornyl acrylate or dihydrodicyclopentadienyl acrylate and from 0 to 10% by weight, preferably from 0 to 5% by weight, of a diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, preferably TCDDMDA; from 3 to 10%, preferably from 4 to 6%, of at least one alkoxysilane (meth)acrylate monomer, preferably trimethoxysilane acrylate;from 0.5 to 4%, preferably from 1 to 3%, of at least one photoinitiator; from 1 to 16%, preferably from 3 to 15%, of methacrylic acid.;

[0023] Preferably, the composition of the invention comprises, preferably consists of, by weight per total weight of the composition: from 28 to 32%, of at least one block copolymer; from 45 to 65%, of a mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, said mixture P comprising from 40 to 60% by weight of methyl methacrylate, and from 40 to 60% by weight preferably of isobornyl acrylate and from 0 to 5% by weight of TCDDMDA; from 4 to 6%, of trimethoxysilane acrylate; from 1 to 3%, of at least one photoinitiator; from 3 to 15%, of methacrylic acid.

[0024] In one embodiment, the composition is a single-component composition.

[0025] Preferably, the composition of the invention has a glass transition temperature after polymerization of at least 85°C, preferably at least 90°C, more preferably at least 100°C.

[0026] The invention also relates to an adhesive product comprising the photopolymerizable adhesive composition according to the invention and an opaque container containing it.

[0027] The invention also relates to an adhesive obtained by the method comprising the following steps: application of a photopolymerizable adhesive composition according to the invention to at least one cover and / or an electronic or optoelectronic device; photopolymerization of the applied photopolymerizable adhesive composition to obtain a polymerized adhesive; and optionally shaping of the polymerized adhesive.

[0028] The present application also relates to an electronic or optoelectronic module comprising the assembly of a series of layers comprising, in this order: a first cover; a first adhesive according to the invention or obtained from the adhesive photopolymerizable composition according to the invention; a flexible electronic or optoelectronic device; a second adhesive according to the invention or obtained from the adhesive photopolymerizable composition according to the invention; and a second cover. Preferably, the electronic or optoelectronic module according to which the flexible electronic or optoelectronic device is chosen from organic light-emitting diodes, organic photovoltaic cells, organic transistors, or organic sensors, or a combination of these devices.

[0029] Preferably, the electronic or optoelectronic module according to which the flexible electronic or optoelectronic device is a perovskite type device.

[0030] The application also relates to a method for obtaining the module according to the invention, the method comprising the following steps: providing an electronic or optoelectronic device; providing an adhesive photopolymerizable composition according to the invention; providing a first cover; providing a second cover; applying layers of adhesive photopolymerizable composition to the surface of the device and / or to respective internal surfaces of the first and second covers; laminating the device and the layers of adhesive photopolymerizable composition between the respective internal surfaces of the first and second covers; and photopolymerizing the layers of adhesive photopolymerizable composition.

[0031] The present application also relates to the use of the adhesive photopolymerizable composition according to the invention, or of the adhesive according to the invention, for the encapsulation of flexible electronic or optoelectronic devices.

[0032] The inventors have shown that a combination of methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C and monoacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C and optionally diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C, advantageously makes it possible to improve the polymerization kinetics and the conversion of the adhesive photopolymerizable composition of the invention, compared to a composition comprising only a methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C. This advantageously makes it possible to improve industrial productivity for the manufacture of electronic or optoelectronic modules.The inventors have also advantageously shown that this combination makes it possible to limit the shrinkage linked to the polymerization of the photopolymerizable composition.

[0033] Description of figures

[0034] Figure 1 represents the evolution of the active surface area as a function of time for the reference composition (CExC) and compositions 1 and 2 according to the invention (respectively Exl and Ex2).

[0035] Figure 2 represents the VA for the reference composition (CExC) and compositions 1 and 2 according to the invention (respectively Exl and Ex2).

[0036] Figure 3 represents the DA12 for the reference composition (CExC) and compositions 1 and 2 according to the invention (respectively Exl and Ex2).

[0037] Figure 4 represents the evolution of the average thickness of the active surface as a function of time for the reference composition (CExC) and compositions 1 and 2 according to the invention (respectively Exl and Ex2).

[0038] Figure 5 represents the VE for the reference composition (CExC) and compositions 1 and 2 according to the invention (respectively Exl and Ex2).

[0039] Figure 6 represents the DE380 for the reference composition (CExC) and compositions 1 and 2 according to the invention (respectively Exl and Ex2).

[0040] Detailed description

[0041] The invention is now described in more detail and in a non-limiting manner in the following description.

[0042] Unless otherwise stated, all percentages are by mass.

[0043] In this text, the quantities indicated for a given species may apply to this species according to all its definitions (as mentioned in this text), including the more restricted definitions.

[0044] By "flexible" or "soft" we mean the ability of a material, in particular due to its intrinsic properties and / or its low thickness, to bend, curve and / or fold easily.

[0045] “Flexible electronic or optoelectronic device” (and the module obtained from it) means a device (a module) retaining its electronic conductive or semiconductive properties even when bent with a very small radius of curvature without risk of buckling or delamination of the electronic components.

[0046] By "adhesive" is meant the matrix / structure formed around the electronic or optoelectronic device by the photopolymerized adhesive composition. The terms "adhesive" or "encapsulant" are currently used interchangeably.

[0047] By “module” we mean the assembly of the electronic or optoelectronic device coated with the polymerized adhesive composition and inserted between the two covers.

[0048] The term "cover" refers to the elements between which the coated electronic or optoelectronic device is laminated. Currently, this element may be referred to interchangeably as "support", "plate" or "sheet".

[0049] By "photopolymerizable composition" or "photocrosslinkable composition" is meant a composition for which the initiation (starting) of polymerization is triggered by exposure to electromagnetic radiation, in particular ultraviolet (UV) radiation.

[0050] By "photopolymerizable adhesive composition" is advantageously meant a composition developing adhesive properties when it is subjected to electromagnetic radiation, in particular to ultraviolet (UV) radiation, which initiates (starts) the polymerization thereof.

[0051] A "monomer" means a molecule that can undergo polymerization. When the term "monomer" is used to refer to a constituent of a polymer, it means the unit (or residue) derived from the monomer - or monomer unit / monomer unit - by polymerization with at least one other monomer.

[0052] Polymerization means a process of transforming a single type of monomer or a mixture of different types of monomers into a polymer.

[0053] By "polymer" we mean a copolymer or a homopolymer.

[0054] By "homopolymer" we mean a polymer grouping together several identical monomer units.

[0055] By "copolymer" we mean a polymer grouping together at least two different types of monomer units (called co-monomers).

[0056] By "oligomer" is meant a small polymer compound, obtained by polymerization of 2 to 30 monomers (comprising 2 to 30 monomer units), i.e. whose degree of polymerization is between 2 and 30.

[0057] A "block copolymer" means a polymer comprising one or more uninterrupted sequences of each of the distinct polymer species, the polymer sequences being chemically different from each other and being linked together by a covalent bond. These polymer sequences are also referred to as polymer blocks.

[0058] By "(meth)acrylic" (or "(meth)acrylate") is meant any type of acrylic and / or methacrylic (or acrylate and / or methacrylate) compound, polymer, monomer or oligomer. For example, (meth)acrylic acid means acrylic acid or methacrylic acid, isobornyl (meth)acrylate means isobornyl acrylate or isobornyl methacrylate, etc.

[0059] Polymerization is a chemical process that binds molecules together to form a three-dimensional network.

[0060] By "initiator" or "primer" is meant a chemical species that reacts with a monomer to form an intermediate compound capable of successfully bonding with a large number of other monomers to form a polymer or that reacts with polymers to initiate the process of molecular interconnection known as polymerization.

[0061] By "Tg" is meant the glass transition temperature of the polymer material. The glass transition temperature can be measured by differential scanning calorimetry (DSC), for example using the half-height tangent method measured between two inflection points located between 40 and 140°C, during the third heating cycle. In the context of the present invention, certain monomers are described by the Tg that the homopolymers obtained after polymerization of said monomers would have. In this case, the Tg is measured in the following manner: the monomer is polymerized until maximum conversion thus forming the homopolymer, the measurement of the Tg of the resulting homopolymer is carried out by DSC as mentioned above.

[0062] By "room temperature" we mean a temperature of around 20°C.

[0063] By "substantially free of" is meant a composition comprising less than 1%, preferably less than 0.1%, preferably less than 0.01%, preferably about 0%, of a compound, by weight per total weight of the composition.

[0064] It should be understood that by "mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C" the present invention means a mixture P of (meth)acrylate monomers in which each of said (meth)acrylate monomers is characterized in that the homopolymer obtained after polymerization of each of said monomers has a glass transition temperature of at least 85°C. Photopolymerizable adhesive composition

[0065] In a first aspect, the present invention relates to a photopolymerizable adhesive composition.

[0066] Block copolymer

[0067] The composition comprises at least one block copolymer, preferably at least one (meth)acrylic block copolymer.

[0068] The composition may comprise from 20 to 35%, preferably from 25 to 35%, even more preferably from 28% to 32% of at least one block copolymer, by weight per total weight of the composition.

[0069] By "(meth)acrylic block copolymer" is meant a (meth)acrylic block copolymer comprising 10% or less (e.g. 0.1 to 10%), preferably 5% or less (e.g. 0.1 to 5%), of at least one non-(meth)acrylic monomer, by weight per total weight of the copolymer. The non-(meth)acrylic monomer may be selected from the group consisting of butadiene, isoprene, styrene, vinylnaphthalene, a cyclosiloxane monomer, vinylpyridine and their derivatives (e.g. α-methylstyrene or tert-butylstyrene).

[0070] The block copolymer may be chosen from block copolymers comprising at least one block M and at least one block B, in particular block copolymers having the diblock structure BM (or diblock copolymer BM) or the triblock structure MBM (or triblock copolymer MBM), in which each block is connected to the other by means of a covalent bond or an intermediate molecule connected to one of the blocks by a covalent bond and to the other block by another covalent bond. The block copolymer is preferably a triblock copolymer MB-M.

[0071] The M block denotes a polymer block comprising at least 50% by weight of methyl methacrylate. The M block may denote a homopolymer block of polymethyl methacrylate (PMMA - 100% by weight of methyl methacrylate) or a copolymer block comprising at least 50% by weight of methyl methacrylate and 50% or less of another monomer, other than methyl methacrylate, by weight per total weight of the M block.

[0072] Block B designates an elastomeric polymer block incompatible with block M, and whose glass transition temperature (Tg) is lower than room temperature, preferably lower than 0°C, preferably lower than -20°C.

[0073] With respect to the diblock copolymer BM, the block M may consist of methyl methacrylate monomers. Alternatively, the block M may comprise at least 50% (for example from 50 to 99.9%), preferably at least 75% (for example from 75 to 99.9%), of methyl methacrylate; and 50% or less (for example from 0.1 to 25%), preferably 25% or less (for example from 0.1 to 25%), of at least one other monomer other than methyl methacrylate, by weight per total weight of the block M.

[0074] The other monomer, other than methyl methacrylate, constituting the M block, may be another (meth)acrylic monomer or a non-(meth)acrylic monomer.

[0075] The non-(meth)acrylic monomer may be selected from the group consisting of butadiene, isoprene, styrene, vinylnaphthalene, a cyclosiloxane monomer, vinylpyridine and their derivatives (e.g. α-methylstyrene or tert-butylstyrene).

[0076] The other (meth)acrylic monomer may be selected from the group consisting of methyl acrylate, ethyl (meth)acrylate, (meth)acrylic acid, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, amides derived from (meth)acrylic acid (e.g. N,N-dimethylacrylamide), 2-methoxyethyl (meth)acrylate, 2-aminoethyl (meth)acrylate, polyethylene glycol (PEG) (meth)acrylate, wherein the PEG group has a molar mass ranging from 400 to 10,000 g / mol, and mixtures thereof.

[0077] The elastomeric B-block may consist of alkyl (meth)acrylate monomer. Alternatively, the B-block may comprise at least 95% (e.g., 95 to 99.9%) of alkyl (meth)acrylate; and 5% or less (e.g., 0.1 to 5%) of another monomer other than alkyl (meth)acrylate, by weight per total weight of the B-block.

[0078] The alkyl (meth)acrylate may be chosen from the group consisting of ethyl acrylate (Tg of the homopolymer obtained after polymerization = -24°C), butyl acrylate (Tg of the homopolymer obtained after polymerization = -54°C), 2-ethylhexyl acrylate (Tg of the homopolymer obtained after polymerization = -85°C), hydroxyethyl acrylate (Tg of the homopolymer obtained after polymerization = -15°C), 2-ethylhexyl methacrylate (Tg of the homopolymer obtained after polymerization = -10°C) and mixtures thereof; preferably the alkyl (meth)acrylate is butyl acrylate.

[0079] The other monomer, other than alkyl (meth)acrylate, may be selected from the group consisting of butadiene, isoprene, styrene, vinylnaphthalene, a cyclosiloxane monomer, vinylpyridine and their derivatives (e.g. α-methylstyrene or tert-butylstyrene). The BM diblock copolymer may have a number-average molar mass of between 10,000 and 500,000 g / mol, preferably between 20,000 and 200,000 g / mol.

[0080] The diblock copolymer BM may comprise a mass fraction (by weight per total weight of the copolymer) of between 5 and 95%, preferably between 15 and 85%, in block M; and between 5 and 95%, preferably between 15 and 85%, in block B.

[0081] In the case of the MBM triblock copolymer, the two M blocks are made up of the same monomers (or comonomers) as the M block of the BM diblock copolymer as described above. These two M blocks may be identical or different. For example, these two M blocks may be different in molar mass, but be made up of the same monomers.

[0082] The B block consists of the same monomers (or co-monomers) as the B block of the BM diblock copolymer as described above.

[0083] The MBM triblock copolymer may have a number-average molar mass of between 10,000 g / mol and 500,000 g / mol, preferably between 20,000 and 200,000 g / mol.

[0084] The MBM triblock copolymer may comprise a mass fraction (by weight per total weight of the copolymer) of between 10 and 80%, preferably between 15 and 70%, preferably between 40 and 60%, in M ​​blocks; and between 20 and 90%, preferably between 30 and 85%, preferably between 40 and 60%, in B block.

[0085] Preferably, the MBM triblock copolymer is a polymethylmethacrylate-poly(styrene-co-butylacrylate)-polymethylmethacrylate block copolymer.

[0086] Block copolymers may be manufactured by controlled radical polymerization (CRP), for example according to the methods as described in PCT applications WO 96 / 24620 A and WO 00 / 71501 A1, or by anionic polymerization.

[0087] One or less of the M and B blocks may be functionalized by means of one or more functions selected from the group consisting of acid, amine, amide, epoxy, thiol functions, quaternary ammonium groups, chlorinated groups and fluorinated groups.

[0088] Block copolymers are commercially available under the name Nanostrength® from Arkema.

[0089] Mono-acrylate monomers

[0090] The composition comprises from 45 to 75% by weight, relative to the total weight of the composition, of a mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C, said mixture P comprising at least one methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C and at least 5% by weight of an acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C.

[0091] The composition of the invention preferably comprises from 45 to 75%, preferentially from 45 to 70%, even more preferentially from 45 to 65%, of the mixture P, by weight per total weight of the composition.

[0092] Preferably, the mixture P comprises:

[0093] - from 20% to 95% by weight, more preferably from 20% to 80% by weight, and even more preferably from 30% to 70%, preferably from 40 to 60%, by weight relative to the weight of mixture P, of at least one methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C and

[0094] - at least 5%, preferably at least 10%, more preferably from 5 to 80%, more preferably from 20% to 80%, even more preferably from 30% to 70%, preferably from 40 to 60% by weight of a mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C. Preferably, the quantity by weight of mono-acrylate monomer in the mixture P is such that the viscosity of the adhesive photopolymerizable composition according to the invention obtained has a viscosity of 100 to 20,000 mPa.s, preferably a viscosity of 100 to 10,000 mPa.s, preferably from 500 to 5,000 mPa.s, more preferably from 1,000 to 2,500 mPa.s. Viscosity can be measured according to standard NF EN 12092 “Adhesives - Determination of viscosity” using a Brookfield DVIII Ultra viscometer (rotary: SC4-27, rotation: 20 rpm, temperature: 25°C).

[0095] The methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C may be chosen from the group consisting of methyl methacrylate, tert-butyl methacrylate, phenyl methacrylate, isopropyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, and mixtures thereof, preferably the methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C is methyl methacrylate.

[0096] The mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C can be chosen from the group consisting of isobornyl acrylate, dihydrodicyclopentadienyl acrylate, and mixtures thereof, preferably the acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C is isobornyl acrylate.The mixture P may further comprise from 0 to 40% by weight, preferably from 0 to 20% by weight or from 1 to 20% by weight, more preferably from 0 to 10% by weight or from 1 to 10% by weight, preferably from 0 to 5% by weight or from 1 to 5% by weight, of at least one diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, in particular dipropylene glycol diacrylate (CAS No. 57472-68-1), neopentyl glycol hydroxypivalate diacrylate (CAS No. 2136366-99-7), tricyclodecanedimethanol diacrylate (CAS No. 52594-17-2), preferably the diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C is tricyclodecanedimethanol diacrylate (TCDDMDA).

[0097] Alkoxysilane (meth)acrylate monomers

[0098] The composition comprises at least one alkoxysilane (meth)acrylate monomer.

[0099] The composition may comprise from 2 to 15%, preferably from 3 to 10%, preferably from 4 to 6%, of at least one alkoxysilane (meth)acrylate monomer, by weight per total weight of the composition.

[0100] The alkoxysilane (meth)acrylate monomer, including the alkyl alkoxysilane (meth)acrylate monomer, may be chosen from the group consisting of trialkoxysilane (meth)acrylate monomers; preferably trimethoxysilane (meth)acrylate monomers; preferably the alkoxysilane (meth)acrylate monomer is chosen from the group consisting of 3-(trimethoxysilyl)propyl acrylate, 3-(trimethoxysilyl)propyl methacrylate, trimethoxysilyl acrylate, trimethoxysilyl methacrylate and mixtures thereof; preferably the alkoxysilane (meth)acrylate monomer is 3-(trimethoxysilyl)propyl methacrylate.

[0101] 3-(Trimethoxysilyl)propyl methacrylate is commercially available as Silquest® A174 from Momentive®.

[0102] Photoinitiator

[0103] The composition comprises at least one photoinitiator. Any compound capable of initiating the photopolymerization of the adhesive composition, in particular any compound capable of initiating the radical polymerization of the urethane (meth)acrylate monomers and / or oligomers by ultraviolet (UV) or visible light irradiation, to obtain the adhesive, may be used.

[0104] The composition may comprise from 0.1 to 5%, preferably from 0.5 to 4%, preferably from 1 to 3%, of at least one photoinitiator, by weight per total weight of the composition. The photoinitiator may be chosen from the group consisting of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, triethylbenzoyl-diphenylphosphine oxide, thioxanthen-9-one, 4,4-bis(diethylamino)benzophenone, 9,10-phenanthrene quinone, benzoyltrimethylgermane, dibenzoyldiethylgermane, bis-(4-methoxybenzoyl)diethylgermanium and mixtures thereof; preferably phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. A mixture may comprise, for example, benzophenone, α-hydroxyketone and triethylbenzoyl-diphenylphosphine oxide. Another mixture may comprise, for example, benzoyltrimethylgermane, dibenzoyldiethylgermane and bis-(4-methoxybenzoyl)diethylgermanium.

[0105] Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide is commercially available under the name Omnirad® 819 from IGM Resins

[0106] (formerly Irgacure® 819 from Ciba® Specialty Chemicals). The mixture comprising benzophenone, α-hydroxyketone and triethylbenzoyl-diphenylphosphine oxide is commercially available under the name Esacure® KTO 46 from Lehvoss. Other (meth)acrylate monomer

[0107] The composition may comprise at least one (meth)acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of less than 0°C. In this embodiment, the composition comprises the mixture of a (meth)acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C and a (meth)acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of less than 0°C.

[0108] The composition may comprise from 0 to 5% of at least one (meth)acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of less than 0°C, by weight per total weight of the composition. If present, the composition may comprise from 0.1 to 5% of at least one (meth)acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of less than 0°C, by weight per total weight of the composition.

[0109] The (meth)acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of less than 0°C may be chosen from the group consisting of butyl acrylate, ethyl acrylate, propyl acrylate, hexyl acrylate, octyl acrylate, dodecyl acrylate, isopropyl acrylate, isobutyl acrylate, isodecyl acrylate, 2-ethylhexyl acrylate, 2-propylheptyl acrylate, isodecyl methacrylate, dodecyl methacrylate, 2-hydroxyethyl acrylate and mixtures thereof; preferably butyl acrylate.

[0110] Preferably, the composition may be substantially free of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of less than 0°C.

[0111] Methacrylic acid

[0112] The composition may comprise the monomer methacrylic acid.

[0113] It should be understood that the methacrylic acid monomer is not a methacrylate of the mixture P.

[0114] The composition may comprise from 0 to 20% of methacrylic acid, by weight per total weight of the composition. If present, the composition comprises from 1 to 16%, preferably from 3 to 15%, of methacrylic acid, by weight per total weight of the composition.

[0115] Preferably, the composition comprises from 5% to 12% of methacrylic acid by weight relative to the total weight of the composition.

[0116] Urethane (meth)acrylate oligomer

[0117] The composition may comprise at least one urethane (meth)acrylate oligomer.

[0118] The composition may comprise from 0 to 7% of at least one urethane (meth)acrylate oligomer, by weight per total weight of the composition. If present, the composition comprises from 0.1 to 7%, preferably from 3 to 6%, of at least one urethane (meth)acrylate oligomer, by weight per total weight of the composition.

[0119] Preferably, the composition is substantially free of urethane (meth)acrylate oligomer.

[0120] The urethane (meth)acrylate oligomer may be chosen from aliphatic urethane diacrylate oligomers, preferably the urethane (meth)acrylate oligomer is aliphatic urethane diacrylate.

[0121] The composition may further comprise at least one monofunctional reactive diluent.

[0122] The composition may comprise from 0 to 0.7% of at least one monofunctional reactive diluent, by weight per total weight of the composition. If present, the composition comprises from 0.1 to 0.7%, preferably from 0.3 to 0.7%, of at least one monofunctional reactive diluent, by weight per total weight of the composition.

[0123] The monofunctional reactive diluent may be 2-(2-ethoxy-ethoxy) ethyl acrylate. The mixture of a urethane (meth)acrylate oligomer and a monofunctional reactive diluent, consisting of about 90% aliphatic urethane diacrylate and about 10% 2-(2-ethoxy-ethoxy) ethyl acrylate by weight per total weight of the mixture, is commercially available under the name CN966H90® from Sartomer.

[0124] Viscosity

[0125] The photopolymerizable adhesive composition is preferably a liquid composition.

[0126] The composition may have a viscosity of 100 to 20,000 mPa.s, preferably 100 to 10,000 mPa.s, preferably 500 to 5,000 mPa.s, more preferably 1,000 to 2,500 mPa.s. The viscosity may be measured according to standard NF EN 12092 “Adhesives - Determination of viscosity” using a Brookfield DVIII Ultra viscometer (rotary: SC4-27, rotation: 20 rpm, temperature: 25°C).

[0127] After polymerization, the composition has a glass transition temperature (Tg), preferably of at least 85°C, preferably of at least 90°C, preferably of at least 100°C.

[0128] Preferably, the composition comprises (alternatively consists of): at least one block copolymer; preferably at least one (meth)acrylic block copolymer; preferably a (meth)acrylic block copolymer having an MBM triblock structure; at least one mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, said mixture P comprises at least one methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C chosen from the group consisting of methyl methacrylate, tert-butyl methacrylate, phenyl methacrylate, isopropyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, and mixtures thereof, preferably the methacrylate monomer is methyl methacrylate;and at least 5% by weight relative to the total weight of the mixture P of a mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C chosen from isobornyl acrylate, dihydrodicyclopentadienyl acrylate, and mixtures thereof, preferably the mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C is isobornyl acrylate and optionally from 1% to 20% by weight of a diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C, preferably said diacrylate monomer is chosen from dipropylene glycol diacrylate, neopentyl glycolhydroxypivalate diacrylate, tricyclodecanedimethanol diacrylate, preferably the diacrylate monomer is diacrylate tricyclodecanedimethanol; at least one alkoxysilane (meth)acrylate monomer;preferentially a monomer chosen from the group consisting of trialkoxysilane (meth)acrylate monomers; preferentially trimethoxysilane (meth)acrylate monomers; preferentially 3-(trimethoxysilyl)propyl acrylate, 3-(trimethoxysilyl)propyl methacrylate, trimethoxysilyl acrylate, trimethoxysilyl methacrylate and mixtures thereof; preferentially one monomer being 3-(trimethoxysilyl)propyl methacrylate; at least one photoinitiator; preferentially a photoinitiator chosen from the group consisting of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, triethylbenzoyl-diphenylphosphine oxide, thioxanthen-9-one, 4,4-bis(diethylamino)benzophenone, 9,10-phenanthrene quinone, benzoyltrimethylgermane, dibenzoyldiethylgermane, bis-(4-methoxybenzoyl)diethylgermanium and mixtures thereof; preferentially a photoinitiator being phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and mixtures thereof;

[0129] - optionally at least one (meth)acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature below 0°C; preferably a monomer chosen from the group consisting of butyl acrylate, ethyl acrylate, propyl acrylate, hexyl acrylate, octyl acrylate, dodecyl acrylate, isopropyl acrylate, isobutyl acrylate, isodecyl acrylate, 2-ethylhexyl acrylate, 2-propylheptyl acrylate, isodecyl methacrylate, dodecyl methacrylate, 2-hydroxyethyl acrylate and mixtures thereof; preferably one monomer being butyl acrylate; optionally the methacrylic acid monomer; optionally at least one urethane (meth)acrylate oligomer; preferentially an oligomer chosen from aliphatic urethane diacrylate oligomers; preferentially an oligomer being aliphatic urethane diacrylate;optionally at least one monofunctional reactive diluent; preferably a diluent being 2-(2-ethoxy-ethoxy) ethyl acrylate. Preferably, the composition comprises (alternatively consists of), by weight per total weight of the composition: from 20 to 35%, preferably from 25 to 35%, preferably from 28 to 32%, of at least one block copolymer;from 45 to 75%, preferably from 45 to 70%, preferably from 45 to 65%, of a mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, said mixture P comprising at least one methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C and at least 5% by weight, preferably at least 10% by weight, preferably from 5 to 80% by weight, more preferably from 20 to 80% by weight, even more preferably from 30 to 70% by weight, of a mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C and optionally a diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C; from 2 to 15%, preferably from 3 to 10%, preferably from 4 to 6%, of at least one alkoxysilane (meth)acrylate monomer;from 0.1 to 5%, preferably from 0.5 to 4%, preferably from 1 to 3%, of at least one photoinitiator; from 0 to 5%, of at least one (meth)acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature below 0°C; from 0 to 20%, preferably from 1 to 16%, preferably from 3 to 15%, of methacrylic acid; and from 0 to 0.7% of at least one monofunctional reactive diluent.;

[0130] Preferably, the composition comprises (alternatively consists of), by weight per total weight of the composition: from 20 to 35%, preferably from 25 to 30%, of at least one block copolymer;from 45 to 75%, preferably from 45 to 70%, preferably from 45 to 65%, of a mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, said mixture P comprising at least one methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C and at least 5% by weight, preferably at least 10% by weight, preferably from 5 to 80% by weight, more preferably from 20 to 80% by weight, even more preferably from 30 to 70% by weight, of a mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C and optionally, from 0 to 40% by weight, preferably from 1 to 20% by weight, of a monomer diacrylate whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C;from 2 to 15%, preferably from 3 to 10%, preferably from 4 to 6%, of at least one alkoxysilane (meth)acrylate monomer; from 0.1 to 5%, preferably from 0.5 to 4%, preferably from 1 to 3%, of at least one photoinitiator; from 0 to 5%, of at least one (meth)acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature below 0°C; from 0 to 20%, preferably from 1 to 16%, preferably from 3 to 15%, of methacrylic acid; from 0 to 0.7% of at least one monofunctional reactive diluent.;

[0131] Preferably, the composition comprises (alternatively consists of), by weight per total weight of the composition: from 25 to 35%, preferably from 28 to 32%, of at least one block copolymer;from 45 to 65%, of a mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, said mixture P comprising from 40 to 60% by weight of a methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, preferably methyl methacrylate, and from 40 to 60% by weight of a mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, preferably isobornyl acrylate or dihydrodicyclopentadienyl acrylate and from 0 to 10% by weight, preferably from 0 to 5% by weight, of a diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, preferably TCDDMDA; from 3 to 10%, preferably from 4 to 6%, of at least one alkoxysilane (meth)acrylate monomer, preferably trimethoxysilane methacrylate;from 0.5 to 4%, preferably from 1 to 3%, of at least one photoinitiator; from 1 to 16%, preferably from 3 to 15%, of methacrylic acid. Preferably, the composition comprises (alternatively consists of), by weight per total weight of the composition: from 28 to 32%, of at least one block copolymer; from 45 to 65%, of a mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, said mixture P comprising from 40 to 60% by weight of methyl methacrylate, and from 40 to 60% by weight preferably of isobornyl acrylate and from 0 to 5% by weight of TCDDMDA; from 4 to 6%, of trimethoxysilane methacrylate, preferably 3-(trimethoxysilyl)propyl methacrylate; from 1 to 3%, of at least one photoinitiator; from 3 to 15%, of methacrylic acid.;

[0132] Single-component composition

[0133] Preferably, the composition is a single-component composition, i.e. a ready-to-use composition. Conversely, preferably, the composition is not a multi-component composition, i.e. a kit comprising at least two separately packaged components, which components are intended to be mixed together extemporaneously, just before application of the composition thus obtained.

[0134] A single-component composition does not need to be prepared in the form of at least two separate components, which must be mixed just before use, in order to avoid premature polymerization. Indeed, the single-component composition comprises at least one photoinitiator, allowing polymerization to be initiated as soon as the composition is exposed to light radiation, in particular ultraviolet (UV) radiation. In order to avoid any premature or untimely polymerization, the composition must not be exposed to light.

[0135] Adhesive product

[0136] In a second aspect, the present invention comprises an adhesive product. The adhesive product comprises the adhesive photopolymerizable composition as described above and an opaque container containing it. By "opaque container" is meant a container whose walls do not allow the passage of light capable of activating the photoinitiator, in particular visible light and ultraviolet radiation (less than 600 nm). The opaque container may be any container capable of containing the composition and retaining its properties, in particular the adhesive properties. The use of an opaque container makes it possible not to expose the composition to light (in particular to ultraviolet radiation) before use, that is to say during its storage and transport, and thus avoids any premature or untimely polymerization.

[0137] The container may be chosen, for example, from the group consisting of a bottle or a tube.

[0138] Adhesive

[0139] In a third aspect, the present invention relates to an adhesive, in particular an adhesive obtained from the photopolymerizable adhesive composition as described above. By "adhesive" or "photopolymerized adhesive composition" is meant the adhesive layer obtained by applying the photopolymerizable adhesive composition, by photopolymerizing it and optionally by shaping the adhesive thus obtained.

[0140] The adhesive is obtained by the process comprising the following steps: application of the photopolymerizable adhesive composition as described above to at least one cover and / or one electronic or optoelectronic device; photopolymerization of the applied composition to obtain a polymerized adhesive; and optionally shaping of the polymerized adhesive.

[0141] The adhesive can take the form of a film.

[0142] The application of the composition can be carried out by a conventional application technique, for example the following techniques: slot-die coating, deep coating, inkjet printing, screen printing, spin coating, spray coating or with a rigid knife applicator (doctor blade).

[0143] Photopolymerization of the composition may be carried out by exposure to ultraviolet (UV) radiation and visible light, in particular by using a UV lamp emitting in a range that allows the photoinitiator to be activated without being absorbed by the encapsulation cap. A suitable UV lamp may be, for example, a UV source of the Delolux® 03S UV LED system type. Photopolymerization may be carried out for between 1 and 10 min.

[0144] The adhesive may have a thickness of 10 to 200 pm, preferably 10 to 100 pm, preferably 10 to 30 pm. The adhesive has a number of advantages, in particular for use at a temperature of at least 70°C, preferably at least 85°C, for example when the electronic or optoelectronic device is a photovoltaic cell or when the device must meet temperature test standards (e.g. automotive applications).

[0145] Advantageously, the adhesive formulation according to the invention allows use of the encapsulated object up to at least 70°C, or even up to at least 85°C, for example when the electronic or optoelectronic device is a photovoltaic cell or when the device must meet temperature test standards (automotive applications for example).

[0146] The adhesive preferably has satisfactory adhesive properties, in particular to allow satisfactory cohesion between the electronic or optoelectronic device and the covers, even for flexible modules.

[0147] The adhesive preferably has satisfactory optical properties, in particular satisfactory transparency, in particular to allow the transmission of light waves to the electronic or optoelectronic device and / or to limit diffraction, in particular when the device is a photovoltaic cell. The adhesive may have a transparency of 90% in transmission between 400 and 800nm. Transparency can be measured by UV-visible transmission spectrometry.

[0148] The adhesive preferably has satisfactory electrical properties, in particular satisfactory electrical insulation properties, in particular to prevent any short circuit inside the module. Electrical insulation properties can be measured using ASTM D149.

[0149] The adhesive preferably has satisfactory resistance, in particular to aging under ultraviolet radiation, abrasion and / or impacts.

[0150] The adhesive preferably has satisfactory barrier properties, in particular barrier properties to water and oxygen (air). The barrier properties can be measured with the ASTM F1249 standard with a water vapor transmission rate of less than 5 g.nr 2 .j 1 , preferably lower than g.nr 2 .) 1, for a thickness of 1 mm, at a temperature of 38°C and a relative humidity of 85%.

[0151] The adhesive preferably has satisfactory elastic properties. Elastic properties, particularly flexibility, can be measured using a cylindrical mandrel flex tester, with the three- or four-point bending test method, or with tensile measurements.

[0152] Electronic or optoelectronic module

[0153] In a fourth aspect, the present invention relates to a module, preferably a flexible module. The module corresponds to an encapsulated electronic or optoelectronic device.

[0154] The module may be obtained by superimposing and assembling a series of layers. The series of layers may comprise, in this order: a first cover; a first adhesive as described above or obtained from the photopolymerizable adhesive composition as described above; an electronic or optoelectronic device; a second adhesive as described above or obtained from the photopolymerizable adhesive composition as described above; and a second cover.

[0155] The electronic or optoelectronic device may itself comprise a semiconductor layer deposited on a support substrate.

[0156] This series of layers may also include additional layers, in particular layers interposed between a cover and an adhesive, for example an additional layer improving the adhesion between the internal surface of a cover and a layer of adhesive composition, a surface treatment of the cover, etc.

[0157] In the module thus obtained, the electronic or optoelectronic device is preferentially coated by the two adhesives, which overlap at their periphery, in order to form a watertight seal. The coating of the electronic or optoelectronic device by the adhesives, and its encapsulation between the two covers, allows it to be isolated from its environment.

[0158] The module thus obtained has satisfactory properties, making it possible to limit, or even prevent, both orthogonal permeation and lateral permeation, while retaining the flexibility properties of the electronic or optoelectronic device.

[0159] The module may have a total thickness of 50 to 500 pm, preferably 50 to 300 pm, preferably 50 to 150 pm.

[0160] The electronic or optoelectronic devices may be chosen from rigid, flexible devices or their combinations; preferably the devices are flexible devices; preferably the devices are chosen from organic light-emitting diodes, organic or perovskite photovoltaic cells, organic or perovskite transistors or sensors, or a combination of these devices.

[0161] In a particular embodiment, the photovoltaic cells are perovskite-type devices. The so-called halogenated perovskite material may comprise in its crystalline structure a metal (for example lead or tin), organic and inorganic cations (for example cesium, formamidinium and / or ammonium), halide anions (for example boron or iodine). Perovskite-type devices are particularly suitable for photovoltaic applications. However, perovskite-type devices may have stability problems over time, due to their sensitivity to the atmosphere, in particular to water vapor.

[0162] The hoods can be the same or different.

[0163] Hoods can be single-layer or multi-layer.

[0164] The hoods can be flexible or rigid, preferably flexible.

[0165] The module may have an orientation, for example in that it comprises a lower or rear cover (commonly referred to as a "backsheet" in English) and an upper or front cover (commonly referred to as a "frontsheet" in English). The upper or front cover is preferably transparent and the lower or rear cover is preferably opaque.

[0166] Depending on the electronic or optoelectronic device used and the desired module characteristics and properties, the covers can have specific properties.

[0167] A hood can be a polymer hood.

[0168] A hood can be an inorganic hood.

[0169] A polymeric cover may comprise at least one fluorinated polymeric layer obtained from at least one fluorinated polymer, for example poly(vinyl fluoride) (PVF), poly(vinylidene fluoride) (PVDF) and their mixture.

[0170] A polymeric cover may comprise at least one polymeric layer obtained from polyethylene terephthalate (PET) (or PET layer) and a fluorinated polymeric layer.

[0171] The fluorinated polymer layer, the PET layer, and their combinations, and the single-layer or multi-layer covers obtained from them, are particularly suitable for use as a lower or rear cover.

[0172] A hood may include at least one layer of glass.

[0173] A cover may comprise at least one polymeric layer obtained from polymethyl methacrylate (PMMA) (or PMMA layer). The glass layer or PMMA layer is particularly suitable for use as a top or front cover.

[0174] A flexible cover, particularly suitable for the encapsulation of flexible electronic or optoelectronic devices, in particular organic or perovskite type cells, is commercially available under the name 3M Ultra-Barrier Solar Film from 3M®. This cover is a laminated multilayer cover comprising a PET film, an inorganic barrier layer of silica, alumina or silicon nitride type of 20 to 300 nm, a so-called PSA film (pressure sensitive adhesive) and a fluoropolymer film or layer called "weathering layer" placed in an external situation in order to protect the entire environment.

[0175] Process for obtaining the electronic or optoelectronic module

[0176] In a fifth aspect, the present invention relates to a method for obtaining the module as described above, the method comprising the following steps: providing an electronic or optoelectronic device; providing an adhesive photopolymerizable composition as described above; providing a first cover; providing a second cover; applying layers of adhesive photopolymerizable composition to the surface of the device and / or to respective inner surfaces of the first and second covers; laminating the device and the layers of adhesive photopolymerizable composition between the respective inner surfaces of the first and second covers; and photopolymerizing the layers of adhesive photopolymerizable composition.

[0177] The method may also comprise a step of irradiating the first cover and / or the second cover with ultraviolet-ozone radiation before the application step and / or the lamination step.

[0178] In a particular embodiment, the rigid modules are obtained by a vacuum lamination technique (referred to as “sheet to sheet” in English).

[0179] In a particular embodiment, the flexible modules are obtained by a continuous “roll-to-roll” technique, as described for example in the article by S. Razza et al., entitled “Research Update: Large-area deposition, coating, printing, and processing techniques for the upscaling of perovskite solar cell technology”, APL Materials (2016) 4(9). This technique is particularly suitable for flexible electronic or optoelectronic devices; preferably devices chosen from organic light-emitting diodes, organic or perovskite photovoltaic cells, organic or perovskite transistors and sensors, or a combination of these devices; preferably perovskite-type devices.

[0180] Applications and Uses

[0181] In a sixth aspect, the present invention relates to the use of the adhesive photopolymerizable composition as described above, and of the adhesive as described above obtained therefrom, for the encapsulation of electronic or optoelectronic devices, in particular for the encapsulation of flexible electronic or optoelectronic devices, for example for the encapsulation of organic photovoltaic devices, in particular perovskite type devices.

[0182] EXAMPLES

[0183] The following examples illustrate the invention without limiting it.

[0184] List of materials and equipment

[0185] Block copolymer: MBM triblock copolymer [polymethylmethacrylate-poly(styrene-co-butylacrylate)-polymethylmethacrylate block copolymer] (abbreviation: MBM) supplied by Arkema.

[0186] Methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C: methyl methacrylate (abbreviation: MAM)

[0187] Monoacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C: isobornyl acrylate (abbreviation: IBOA)

[0188] Acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C: tricyclodecanedimethanol diacrylate (abbreviation: TCDDMDA) supplied by Arkema

[0189] Alkoxysilane (meth)acrylate monomers: 3-(trimethoxysilyl)propyl methacrylate, (Momentive® product Silquest® A174) (abbreviation: A174) Photoinitiators: phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (abbreviation: BAPO) available from Sigma-Aldrich

[0190] Methacrylic acid (abbreviation: AMA)

[0191] Light source: UV LED Delolux® 03S system

[0192] Modules to test

[0193] The modules to be tested are commonly referred to as test pieces.

[0194] PK layer: perovskite layer of formula Cso.osFAo.gsPbOo.ssBro, 12)3 with a surface area of ​​4x4 cm (16 cm 2 )

[0195] Glass layer: layer with a surface area of ​​5x5 cm (25 cm 2 )

[0196] ITO layer: tin-doped indium oxide layer

[0197] The glass, ITO layers form the supporting substrate as such.

[0198] The PK layers are deposited using spin coating technology. The top ITO layer is deposited using physical vapor deposition.

[0199] The perovskite layers are deposited on the support substrate, with a 5 mm overhang between the edge of the substrate and the perovskite layer.

[0200] The modules are individually encapsulated between two glass covers with a thickness of 1.2 mm using the photopolymerizable compositions to be tested.

[0201] Test methods

[0202] Viscosity measurements

[0203] The viscosity of the compositions was measured according to standard NF EN 12092 “Adhesives - Determination of viscosity” using a Brookfield DVIII Ultra viscometer (rotary: SC4-27, rotation: 20 rpm, temperature: 25°C).

[0204] Polymerization and conversion kinetics

[0205] The polymerization kinetics and the final conversion rate of the photopolymerizable composition are determined by real-time Fourier transform infrared spectroscopy (RT-FTIR). The composition to be characterized is deposited in the form of a 300 μm thick film between two polypropylene films. The sample is placed in an RT-FTIR spectrophotometer allowing continuous measurement of the infrared absorption spectrum of the composition during its irradiation under the light of a light-emitting diode (LED) lamp with a wavelength of 395 nm and a power of 630 mW / cm 2. The measurement of the absorbance at the frequency of 6170 nm, which corresponds to one of the infrared absorption peaks characteristic of the double bond of the (meth)acrylate functions, makes it possible to follow the conversion rate of the monomer over time (expressed as a % of the number of moles of double bonds which have reacted relative to the number of moles of initial double bonds). After a few tens of seconds, this conversion rate reaches a plateau, which expresses the maximum conversion rate of the composition under these irradiation conditions. The conversion at time t in percentage (denoted conversion (t)) is calculated by the following relation: conversion (t) = (AO - At) / (A0) xlOO with AO and At the absorbance at time t=0 and at time t considered, respectively.

[0206] From this conversion curve as a function of irradiation time, the efficiency of the polymerization kinetics is evaluated by calculating the propagation constant (kp) and the maximum polymerization rate (Rp). In Table 2, kp.[P«] corresponds to the slope of the curve In ([M0] / [Mt]) as a function of time with [MO] and [Mt] the concentration of (meth)acrylate functions at time t=0 and at time t considered, respectively. In this equation kp corresponds to the propagation rate constant and [P«] the stationary concentration of propagating radicals. The term Rp / [M0] xlOO corresponds to the maximum slope of the conversion vs. time curve. It is relative to the maximum polymerization rate. A system will be all the more efficient in terms of polymerization kinetics as the values ​​of kp, [P«] and Rp are high.

[0207] Thermal properties and gas barriers

[0208] The thermal properties of the tested modules were analyzed using a differential scanning calorimetry (DSC). Measurements were performed over three cooling-heating cycles ranging from -80 to 200°C at a rate of 10°C per minute. The glass transition temperature was measured over the third heating cycle using the mid-height tangent method, calculated between 40° and 140°C.

[0209] The gas barrier properties were determined by an optical test measuring the degradation kinetics of the Perovskite layer of the specimen. The degradation of the tested modules was assessed with the following method: the specimen as described above is placed in a climatic chamber at a temperature of 85°C and a relative humidity of 85% in accordance with the climatic conditions for testing photovoltaic modules reported in the standard method IEC 61615, in order to determine an algorithmic parameter of degradation rate (cm 2 / h). See the article by E. Booker et al. entitled “Perovskite Test: A high throughput method to screen ambient encapsulation conditions”, Energy Technology (2020) 8(12) and the article by N. Taherimakhsousi et al. “A machine vision tool for facilitating the optimization of large area perovskite photovoltaics” npj Computational Materials (2021) 190, the latter article describing more specifically the algorithm used. Photographic images of the specimens are taken regularly, for example approximately every 48 hours, in order to evaluate the aging of the perovskite layers. During these tests, the area of ​​the “active” surface, which is the area of ​​the Perovskite (PK) layer with a thickness greater than an empirical threshold (180nm), knowing that the initial thickness of PK is 400 nm for all tests and that the initial area is of the order of 14 cm 2for all tests, is measured. Monitoring this area makes it possible to determine the VA parameter (rate of degradation of the layers in cm 2 / h) by the linear regression established between 12 and 3 cm 2 , and the parameter DA12 (figure 3) which is the time after which the “active” surface reaches 12cm 2 .

[0210] Monitoring the average thickness of the “active” surface makes it possible to determine the VE parameter (thickness degradation rate) obtained by linear regression established between 340 and 230 nm, and the DE380 parameter, corresponding to the time after which the average thickness, starting from 400 nm, reaches 380 nm.

[0211] Photopolymerizable adhesive compositions

[0212] The following photopolymerizable adhesive compositions were prepared (see Table 1, proportions expressed as a mass percentage relative to the total weight of the photopolymerizable adhesive composition):

[0213] Table 1

[0214] 3g of BAPO photoinitiator was added per 100g of composition mentioned in Table 1.

[0215] Compositions CExA, CExB and CExC are comparative compositions. Compositions Ex1 and Ex2 according to the invention have viscosity levels compatible with the method used, i.e. a viscosity of between 200 and 10,000 cP. Compositions CExA and CExB are too viscous to be handled.

[0216] Results

[0217] Kinetics and conversion

[0218] Table 2 below summarizes the kinetic and conversion data obtained for the compositions according to the invention (Exl and Ex2) and for the comparative composition (CExC), each of the compositions was tested twice.

[0219] Table 2

[0220] In Table 2, it can be noted that the Exl and Ex2 formulations have a significantly higher polymerization efficiency with kp, [P«] and Rp values ​​much higher than those of the reference (CExC). The maximum Conversion Rate is also higher on Exl and Ex2 compared to CexC.

[0221] Vapor barrier

[0222] The degradation rate of multilayer modules obtained with the compositions Exl and Ex2 according to the invention and the comparative composition CExC is tested.

[0223] The tested modules are photographed at regular intervals. The shots are taken at 0, 159h, 280h, 351h, 447h, 521h, 624h, 737h, 852h, 948h and 1091h.

[0224] From these snapshots several parameters are extracted which are:

[0225] • Area of ​​the “active” surface (figure 1) which is the area of ​​the Perovskite (PK) layer with a thickness greater than an empirical threshold (180nm) knowing that the initial thickness of PK is 400 nm for all tests and that the initial area is of the order of 14 cm 2 for all tests. o Monitoring this area allows us to determine the VA parameter (figure 2) by the linear regression established between 12 and 3 cm2. We note that the VA parameter is similar for the 3 formulations. o This same area monitoring allows us to define the DA12 parameter (figure 3) which is the time after which the “active” surface reaches 12cm 2 . It is observed that DA12 is similar for the formulations.

[0226] • Monitoring of the average thickness of the “active” surface (figure 4): o the VE parameter (figure 5) obtained by the linear regression established between 340 and 230 nm. It is noted that VE is better for the compositions according to the invention. o The DE380 parameter (figure 6), corresponding to the time after which the average thickness, starting from 400 nm, reaches 380 nm, for which it is noted that the 3 formulations have very close values

[0227] Withdrawal

[0228] The linear shrinkage during polymerization of the three example formulas was measured. This measurement was carried out by photorheology using a Thermofischer Haake Mars 40 plane / plane apparatus by monitoring in real time the thickness (denoted h) of the sample in the air gap of the rheometer under irradiation with a 286 MW / cm mercury UV lamp. 2, at a shear rate of 0.01%, the temperature is stabilized at 25°C for 120 s before starting the measurement. The shrinkage is then calculated as the percentage contraction of the term h. The results are given in Table 3 below.

[0229] Table 3

[0230] The compositions of the invention therefore allow a significant reduction in shrinkage.

Claims

Claims 1. Photopolymerizable adhesive composition comprising, by weight per total weight of the photopolymerizable adhesive composition: from 20 to 35% of at least one block copolymer, preferably a (meth)acrylic block copolymer; from 45 to 75% of a mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C, said mixture P comprising at least one methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C and at least 5% by weight of a monoacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C; from 2 to 15% of at least one alkoxysilane (meth)acrylate monomer; and from 0.1 to 5% of at least one photoinitiator.

2. Adhesive photopolymerizable composition according to claim 1, wherein the block copolymer is chosen from the group consisting of block copolymers comprising at least one block M and at least one block B; said block M designating a polymer block comprising at least 50% by weight of methyl methacrylate; and block B designating an elastomeric polymer block incompatible with block M, and whose glass transition temperature (Tg) is less than 20°C.

3. Photopolymerizable adhesive composition, according to one of the preceding claims, according to which the mixture P comprises at least one methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C chosen from the group consisting of methyl methacrylate, tert-butyl methacrylate, phenyl methacrylate, isopropyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, and mixtures thereof, preferably the monomer methacrylate is methyl methacrylate; and at least 5% by weight relative to the total weight of the mixture P of a mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C chosen from isobornyl acrylate, dihydrodicyclopentadienyl acrylate, and mixtures thereof, preferably the mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C is isobornyl acrylate.

4. Photopolymerizable adhesive composition according to one of the preceding claims, in which the mixture P further comprises at least one diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C, preferably said diacrylate monomer is chosen from dipropylene glycol diacrylate, neopentyl glycol hydroxypivalate diacrylate, tricyclodecanedimethanol diacrylate, preferably the diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C is tricyclodecanedimethanol diacrylate (TCDDMDA).

5. Photopolymerizable adhesive composition, according to one of the preceding claims, in which the mixture P comprises: - from 20% to 95% by weight, more preferably from 20% to 80% by weight, and even more preferably from 30% to 70%, preferably from 40 to 60%, by weight relative to the weight of mixture P, of at least one methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C; - at least 5%, preferably at least 10%, more preferably from 5 to 80%, more preferably from 20% to 80%, even more preferably from 30% to 70%, preferably from 40 to 60% by weight of a monoacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C; and from 1 to 20% by weight, more preferably from 1 to 10% by weight, preferably from 1 to 5% by weight, of at least one monomer diacrylate whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C.

6. Photopolymerizable adhesive composition, according to one of the preceding claims, according to which the alkoxysilane (meth)acrylate monomer is chosen from the group consisting of trialkoxysilane (meth)acrylate monomers.

7. Composition according to any one of the preceding claims comprising, preferably consisting of, by weight per total weight of the composition: from 25 to 35%, preferably from 28 to 32%, of at least one block copolymer;from 45 to 65%, of a mixture P of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, said mixture P comprising from 40 to 60% by weight of a methacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, preferably methyl methacrylate, and from 40 to 60% by weight of a mono-acrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, preferably isobornyl acrylate or dihydrodicyclopentadienyl acrylate and from 0 to 10% by weight, preferably from 0 to 5% by weight, of a diacrylate monomer whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, preferably TCDDMDA; from 3 to 10%, preferably from 4 to 6%, of at least one alkoxysilane (meth)acrylate monomer, preferably trimethoxysilane methacrylate;from 0.5 to 4%, preferably from 1 to 3%, of at least one photoinitiator; from 1 to 16%, preferably from 3 to 15%, of methacrylic acid.; 8. Composition according to any one of the preceding claims comprising, preferably consisting of, by weight per total weight of the composition: from 28 to 32%, of at least one block copolymer; from 45 to 65%, of a mixture P of (meth)acrylate monomers of which the homopolymer obtained after polymerization has a temperature of glass transition of at least 85°C, said mixture P comprising from 40 to 60% by weight of methyl methacrylate, and from 40 to 60% by weight preferably of isobornyl acrylate and from 0 to 5% by weight of TCDDMDA; from 4 to 6%, of trimethoxysilane methacrylate; from 1 to 3%, of at least one photoinitiator; from 3 to 15%, of methacrylic acid.

9. Photopolymerizable adhesive composition, according to one of the preceding claims, in that it is a single-component composition.

10. Photopolymerizable adhesive composition according to any one of the preceding claims, in that it has a glass transition temperature after polymerization of at least 85°C, preferably at least 90°C, more preferably at least 100°C.

11. Adhesive product comprising the photopolymerizable adhesive composition according to one of the preceding claims and an opaque container containing it.

12. Adhesive obtained by the method comprising the following steps: application of a photopolymerizable adhesive composition according to one of claims 1 to 10 on at least one cover and / or an electronic or optoelectronic device; photopolymerization of the applied photopolymerizable adhesive composition to obtain a polymerized adhesive; and optionally shaping of the polymerized adhesive.

13. Electronic or optoelectronic module comprising the assembly of a series of layers comprising, in this order: a first cover; a first adhesive according to claim 12 or obtained from the photopolymerizable adhesive composition according to one of claims 1 to 10; a flexible electronic or optoelectronic device; a second adhesive according to claim 12 or obtained from the photopolymerizable adhesive composition according to one of claims 1 to 10; and a second cover.

14. Electronic or optoelectronic module, according to claim 13, according to which the flexible electronic or optoelectronic device is chosen from organic light-emitting diodes, organic photovoltaic cells, organic transistors, or organic sensors, or a combination of these devices.

15. Electronic or optoelectronic module, according to one of claims 13 or 14, according to which the flexible electronic or optoelectronic device is a perovskite type device.

16. A method for obtaining the module according to one of claims 13 to 15, the method comprising the following steps: providing an electronic or optoelectronic device; providing an adhesive photopolymerizable composition according to one of claims 1 to 10; providing a first cover; providing a second cover; applying layers of adhesive photopolymerizable composition to the surface of the device and / or to respective internal surfaces of the first and second covers; laminating the device and the layers of adhesive photopolymerizable composition between the respective internal surfaces of the first and second covers; and photopolymerizing the layers of adhesive photopolymerizable composition.

17. Use of the photopolymerizable adhesive composition according to one of claims 1 to 10, or of the adhesive according to claim 11 or 12, for the encapsulation of flexible electronic or optoelectronic devices.

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