Photopolymerizable adhesive composition for encapsulating electronic or optoelectronic devices

Abstract

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

Description

Technical Field

[0001] This invention relates to photopolymer adhesive compositions for encapsulating electronic and optoelectronic devices, particularly flexible electronic and optoelectronic devices such as organic and perovskite photovoltaic cells, to protect them from gas and moisture penetration. Background Technology

[0002] There are different types of electronic or optoelectronic devices, including rigid or flexible electronic or optoelectronic devices.

[0003] Depending on the application being considered, such as display applications (e.g., OLED and QLED), photovoltaics (e.g., silicon-based semiconductors, CIGS, CDTE, organic semiconductors, perovskite semiconductors), or sensors, rigid electronic or optoelectronic devices can have different properties.

[0004] Flexible electronic or optoelectronic devices can be defined according to the same application examples, but are applicable to semiconductor technologies compatible with the use of flexible substrates, such as organic light-emitting diode (OLED) devices, organic photovoltaic cells (OPV), amorphous silicon cells (a-Si), CIGS, perovskite semiconductors, organic transistors (OFETs), or organic sensors using organic semiconductors.

[0005] Electronic or optoelectronic devices are sensitive to a variety of factors, such as light, heat, oxygen (air), moisture, pressure, and shock. To ensure optimal efficiency and performance and achieve satisfactory durability, they must be protected and isolated from the environment. This protection must be more effective because their constituent materials are sensitive to the atmosphere, especially water and oxygen. This is particularly true when using organic semiconductors, such as organic, perovskite, or CIGS type semiconductors.

[0006] Different encapsulation technologies have been implemented. These technologies typically involve coating the device with an adhesive composition to obtain an encapsulated device, and then laminating the encapsulated device between two cover plates to obtain an encapsulated device. The choice of adhesive composition and cover plates will depend on the device to be encapsulated. Furthermore, depending on the composition and cover plates used, the resulting electronic or optoelectronic module will have specific characteristics, particularly in terms of weight, thickness, transparency / opacity, rigidity / flexibility, gas and liquid permeability / sealing, shock resistance and / or durability / aging.

[0007] Given this layered arrangement, two types of penetration can be observed: one is orthogonal penetration at the outer surface of the cover sandwiched between the encapsulated devices, and the other is lateral penetration at the free edges of the adhesive within the encapsulation material and at the interface between the two cover layers.

[0008] Lateral permeation protection of this device is ensured specifically through adhesives or encapsulation materials, the effectiveness of which can depend on a variety of factors, including chemical formulation, application process, thickness (proportionate to the surface area exchanged with the environment), interface with the cover plate, and resistance to usage restrictions. Therefore, the properties of the adhesive must be optimized to minimize or even eliminate lateral permeation from atmospheric gases (especially water vapor and oxygen) to ensure optimal efficiency and performance and achieve satisfactory durability.

[0009] Flexible photovoltaic cells (such as organic, perovskite, CIGS, and CDTE cells) are highly attractive alternatives to rigid silicon-based photovoltaic cells because they can be manufactured using continuous high-speed processes (roll-to-roll methods) and are suitable for applications requiring flexibility, conformability, or lightweight. They are also less fragile (using flexible cover plates) and less sensitive to breakage.

[0010] Flexible photovoltaic cells can be obtained, for example, by low-temperature printing and depositing a thin active layer (an organic or perovskite material with semiconductor properties) onto a flexible polymer support substrate.

[0011] Encapsulation of flexible electronic or optoelectronic devices can be achieved through a cover with low permeability (especially water vapor and oxygen), which must be at least as flexible as the device it protects so as not to become a limiting factor for bending the device; or when the encapsulation is used to deliberately limit the bending radius of the device and prevent it from being damaged, the cover must have controlled flexibility.

[0012] Therefore, there is a genuine need for an adhesive composition that allows the production of electronic or optoelectronic modules with satisfactory properties, particularly adhesion, optical properties, thermal properties, electrical properties, gas barrier properties, elasticity, and satisfactory resistive properties. There is also a need for an adhesive composition suitable for encapsulating flexible electronic or optoelectronic devices. Furthermore, there is a need for an adhesive composition that allows the production of electronic or optoelectronic modules exhibiting limited photo-aging (e.g., yellowing) over time. Additionally, there is a need for an adhesive composition that allows the production of electronic or optoelectronic modules exhibiting limited lateral gas and water permeation over time. Finally, there is interest in providing an adhesive composition with a fast polymerization rate and high monomer conversion rate. Summary of the Invention

[0013] This application primarily relates to a photopolymer adhesive composition, which, by weight of the total photopolymer adhesive composition, comprises:

[0014] 20% to 35% of at least one block copolymer, preferably a (meth)acrylic acid block copolymer;

[0015] A mixture P of 45% to 75% (meth)acrylate monomers, wherein the homopolymer obtained after polymerization of the (meth)acrylate monomers has a glass transition temperature (Tg) of at least 85°C, wherein the mixture P comprises at least one methacrylate monomer and at least 5% by weight of a monoacrylate monomer, wherein the homopolymer obtained after polymerization of the methacrylate monomers has a glass transition temperature (Tg) of at least 85°C, and the homopolymer obtained after polymerization of the monoacrylate monomers has a glass transition temperature (Tg) of at least 85°C.

[0016] 2% to 15% of at least one alkoxysilane (meth)acrylate monomer; and

[0017] At least one photoinitiator, ranging from 0.1% to 5%.

[0018] Preferably, the block copolymer is selected from the group consisting of block copolymers with at least one M block and at least one B block;

[0019] The M block refers to a polymer block containing at least 50% methyl methacrylate by weight; and

[0020] The B block refers to an elastic polymer block that is incompatible with the M block, and its glass transition temperature (Tg) is below 20°C.

[0021] In one embodiment, the mixture P comprises: at least one methacrylate monomer, the homopolymer of which, after polymerization, has a glass transition temperature of at least 85°C, and is selected 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, wherein preferably, the methacrylate monomer is methyl methacrylate; and at least 5% by weight of a monoacrylate monomer relative to the total weight of the mixture P, the homopolymer of which, after polymerization, has a glass transition temperature (Tg) of at least 85°C, and is selected from the group consisting of isobornyl acrylate, dihydrodicyclopentadienyl acrylate, and mixtures thereof, wherein preferably, the monoacrylate monomer is isobornyl acrylate, and the homopolymer of which, after polymerization, has a glass transition temperature (Tg) of at least 85°C.

[0022] In one embodiment, the mixture P further includes at least one diacrylate monomer, the homopolymer obtained after polymerization having a glass transition temperature (Tg) of at least 85°C. Preferably, the diacrylate monomer is selected from the group consisting of dipropylene glycol diacrylate, neopentyl glycol hydroxyglutarate diacrylate, and tricyclodecanediol diacrylate. Preferably, the diacrylate monomer is tricyclodecanediol diacrylate (TCDDMDA), and the homopolymer obtained after polymerization of the diacrylate monomer has a glass transition temperature of at least 85°C.

[0023] Preferably, the mixture P comprises:

[0024] - At least one methacrylate monomer, in a weight percentage of 20% to 95%, more preferably 20% to 80%, even more preferably 30% to 70%, and most preferably 40% to 60% relative to the weight of the mixture P, wherein the homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C.

[0025] - At least 5% by weight, preferably at least 10% by weight, more preferably 5% to 80% by weight, more preferably 20% to 80% by weight, even more preferably 30% to 70% by weight, and preferably 40% to 60% by weight, of a monoacrylate monomer, wherein the homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C; and

[0026] - At least one diacrylate monomer, comprising 1% to 20% by weight, more preferably 1% to 10% by weight, and most preferably at least 1% to 5% by weight, wherein the homopolymer obtained after polymerization has a glass transition temperature of at least 85°C.

[0027] In one embodiment, the alkoxysilane (meth)acrylate monomer is selected from the group consisting of trialkoxysilane (meth)acrylate monomers.

[0028] Preferably, based on the total weight of the composition, the composition of the present invention comprises, and preferably consists of, the following:

[0029] - 25% to 35%, preferably 28% to 32%, of at least one block copolymer;

[0030] - A mixture P of 45% to 65% (meth)acrylate monomers, preferably methyl methacrylate, wherein the homopolymer obtained after polymerization of the (meth)acrylate monomers has a glass transition temperature of at least 85°C, wherein the mixture P comprises: 40% to 60% by weight of methacrylate monomers, preferably methyl methacrylate, wherein the homopolymer obtained after polymerization of the methacrylate monomers has a glass transition temperature of at least 85°C; and 40% to 60% by weight of monoacrylate monomers, preferably isobornyl acrylate or dihydrodicyclopentadiene acrylate, wherein the homopolymer obtained after polymerization of the monoacrylate monomers has a glass transition temperature of at least 85°C; and 0 to 10%, preferably 0 to 5% by weight of diacrylate monomers, preferably TCDDMDA, wherein the homopolymer obtained after polymerization of the diacrylate monomers has a glass transition temperature of at least 85°C;

[0031] - 3% to 10%, preferably 4% to 6%, of at least one alkoxysilane (meth)acrylate monomer, preferably trimethoxysilane methacrylate;

[0032] - At least one photoinitiator, at 0.5% to 4%, preferably 1% to 3%;

[0033] - 1% to 16%, preferably 3% to 15% methacrylic acid.

[0034] Preferably, based on the total weight of the composition, the composition of the present invention comprises, and preferably consists of, the following:

[0035] - 28% to 32% of at least one block copolymer;

[0036] - A mixture P of 45% to 65% (meth)acrylate monomers, wherein the homopolymer obtained after polymerization of the (meth)acrylate monomers has a glass transition temperature of at least 85°C, the mixture P comprising 40% to 60% methyl methacrylate, 40% to 60% isobornyl acrylate, preferably 40% to 60% isobornyl acrylate, and 0% to 5% TCDDMDA by weight.

[0037] - 4% to 6% trimethoxysilane methacrylate;

[0038] - 1% to 3% of at least one photoinitiator;

[0039] - 3% to 15% methacrylic acid.

[0040] In one embodiment, the composition is a one-component composition.

[0041] Preferably, the composition of the present invention has a glass transition temperature of at least 85°C, preferably at least 90°C, and more preferably at least 100°C after polymerization.

[0042] The present invention also relates to an adhesive product comprising a photopolymer adhesive composition according to the present invention and an opaque container containing the composition.

[0043] The present invention also relates to an adhesive obtained by a method comprising the following steps:

[0044] The photopolymer adhesive composition according to the present invention is applied to at least one cover plate and / or electronic or optoelectronic device;

[0045] Photopolymerizing the photopolymer adhesive composition described above to obtain a polymerized adhesive; and

[0046] Optionally, the polymerized adhesive is shaped.

[0047] The present invention also relates to an electronic or optoelectronic module comprising a series of layers assembled in the following order:

[0048] First cover plate;

[0049] A first adhesive obtained according to the first adhesive of the present invention or a photopolymer adhesive composition according to the present invention;

[0050] Flexible electronic or optoelectronic devices;

[0051] The second adhesive according to the present invention or the second adhesive obtained by the photopolymer adhesive composition according to the present invention; and

[0052] Second cover plate.

[0053] Preferably, according to the electronic or optoelectronic module, the flexible electronic or optoelectronic device is selected from organic light-emitting diodes, organic photovoltaic cells, organic transistors, or organic sensors, or combinations thereof.

[0054] Preferably, according to the electronic or optoelectronic module, the flexible electronic or optoelectronic device is a perovskite device.

[0055] This application also relates to a method for obtaining a module according to the present invention, the method comprising the following steps:

[0056] Provide electronic or optoelectronic devices;

[0057] Provides a photopolymer adhesive composition according to the present invention;

[0058] Provide the first cover plate;

[0059] Provide a second cover plate;

[0060] Apply a layer of photopolymer adhesive composition to the surface of the device and / or the corresponding inner surfaces of the first and second cover plates;

[0061] A layer of the device and the photopolymer adhesive composition is laminated between the respective inner surfaces of the first and second cover plates; and

[0062] The layer of the photopolymer adhesive composition is photopolymerized.

[0063] This application also relates to the use of a photopolymer adhesive composition according to the present invention or an adhesive according to the present invention for encapsulating flexible electronic or optoelectronic devices.

[0064] The inventors have demonstrated that, compared to compositions containing only methacrylate monomers (whose homopolymers, after polymerization, have a glass transition temperature (Tg) of at least 85°C), monoacrylate monomers (whose homopolymers, after polymerization, have a glass transition temperature (Tg) of at least 85°C), and optionally diacrylate monomers (whose homopolymers, after polymerization, have a glass transition temperature (Tg) of at least 85°C), a combination of these monomers advantageously improves the polymerization kinetics and conversion rate of the photopolymerizable adhesive compositions of the present invention. This advantageously increases the industrial productivity of manufacturing electronic or optoelectronic modules. The inventors have also advantageously demonstrated that this combination is capable of limiting shrinkage of the photopolymerizable compositions due to polymerization. Attached Figure Description

[0065] Figure 1 The changes in active surface area over time are shown for the reference composition (CExC) and compositions 1 and 2 of the present invention (corresponding to Ex1 and Ex2, respectively).

[0066] Figure 2 The reference composition (CExC) and the VA of compositions 1 and 2 of the present invention (corresponding to Ex1 and Ex2, respectively) are shown.

[0067] Figure 3 The reference composition (CExC) and the DA12 of compositions 1 and 2 of the present invention (corresponding to Ex1 and Ex2, respectively) are shown.

[0068] Figure 4 The average thickness of the active surface of the reference composition (CExC) and compositions 1 and 2 of the present invention (corresponding to Ex1 and Ex2, respectively) is shown as a function of time.

[0069] Figure 5 The reference composition (CExC) and the VE of compositions 1 and 2 of the present invention (corresponding to Ex1 and Ex2, respectively) are shown.

[0070] Figure 6 DE380 of the reference composition (CExC) and compositions 1 and 2 of the present invention (corresponding to Ex1 and Ex2, respectively) is shown. Detailed Implementation

[0071] The invention will now be described in more detail in a non-limiting manner in the following description.

[0072] Unless otherwise stated, all percentages are by weight.

[0073] In this article, the quantities shown for a particular species can be applied to that species according to all its definitions (as described herein), including more stringent definitions.

[0074] The term “flexible” or “soft” refers to the ability of a material, especially due to its inherent properties and / or low thickness, to be easily bent, folded and / or folded.

[0075] The term “flexible electronic or optoelectronic device” (and modules derived therefrom) refers to a device (module) that retains its electronic conductivity or semiconductor properties even when bent with a very small radius of curvature, without the risk of warping or delamination of the electronic components.

[0076] The term "adhesive" refers to the matrix / structure formed around the electronic or optoelectronic device by the photopolymer adhesive composition. The terms "adhesive" or "encapsulating agent" are currently used interchangeably.

[0077] The term "module" refers to the electronic or optoelectronic device assembly encapsulated by the polymeric adhesive composition and sandwiched between two cover plates.

[0078] The term "cover" refers to a component that encapsulates electronic or optoelectronic devices laminated within it. Currently, this component is interchangeably referred to as a "support," "plate," or "sheet."

[0079] The term "photopolymerizable composition" or "photocurable composition" refers to a composition that begins to polymerize upon exposure to electromagnetic radiation, particularly ultraviolet (UV) radiation.

[0080] The term "photopolymer adhesive composition" advantageously refers to a composition that exhibits adhesive properties when exposed to electromagnetic radiation (especially ultraviolet (UV) radiation), which initiates (triggers) its polymerization.

[0081] The term "monomer" refers to a molecule that can undergo polymerization. When the term "monomer" is used to refer to a polymer component, it refers to a unit (or residue) derived from a monomer—or monomer unit / structural unit—through polymerization with at least one other monomer.

[0082] The term "polymerization" refers to a method for converting a single type of monomer or a mixture of different types of monomers into a polymer.

[0083] The term "polymer" refers to a copolymer or homopolymer.

[0084] The term "homogeneous polymer" refers to a polymer composed of several identical monomer units.

[0085] The term "polymer" refers to a polymer composed of at least two different types of monomer units (called comonomers).

[0086] The term "oligomer" refers to a small-sized polymer compound obtained by polymerizing 2 to 30 monomers (containing 2 to 30 monomer units), i.e., its degree of polymerization is between 2 and 30.

[0087] The term "block copolymer" refers to a polymer that comprises one or more consecutive sequences of different polymer species that are chemically distinct from each other and linked together by covalent bonds. These polymer sequences are also known as polymer blocks.

[0088] The term "(meth)acrylic acid" (or "(meth)acrylate") refers to any type of compound, polymer, monomer or oligomer, acrylic acid and / or methacrylic acid (or acrylate and / or methacrylate). For example, (meth)acrylic acid refers to acrylic acid or methacrylic acid, and isobornyl methacrylate refers to isobornyl acrylate or isobornyl methacrylate, etc.

[0089] The term "polymerization" refers to a chemical process that allows molecules to link together to form a three-dimensional network.

[0090] The term "initiator" or "trigger" refers to a chemical substance that reacts with monomers to form intermediate compounds or with polymers to initiate a process of molecular interconnection called polymerization, in which the intermediate compound is able to successfully bind to a large number of other monomers to form a polymer.

[0091] The term "Tg" refers to the glass transition temperature of a polymer material. This glass transition temperature can be measured using differential scanning calorimetry (DSC), for example, by using the tangent method at the midpoint between two inflection points between 40°C and 140°C during the third heating cycle. In the context of this invention, certain monomers are described by the Tg value of the homopolymer obtained after polymerization. In this case, the Tg measurement method is as follows: the monomer is polymerized to maximum conversion to form a homopolymer, and then the Tg value of the homopolymer is determined according to the aforementioned DSC method.

[0092] The term "room temperature" refers to a temperature of approximately 20°C.

[0093] The term "substantially free" means that a composition contains less than 1%, preferably less than 0.1%, preferably less than 0.01%, and preferably about 0% of the compound by weight of the composition.

[0094] It should be understood that, for "a mixture P of (meth)acrylate monomers, wherein the homopolymer obtained after polymerization of the (meth)acrylate monomers has a glass transition temperature of at least 85°C", the present invention refers to a mixture P of (meth)acrylate monomers, wherein each (meth)acrylate monomer is characterized in that the homopolymer obtained after polymerization of each monomer has a glass transition temperature of at least 85°C.

[0095] Photopolymer adhesive composition

[0096] In a first aspect, the present invention relates to a photopolymer adhesive composition.

[0097] Block copolymers

[0098] The composition includes at least one block copolymer, preferably at least one (meth)acrylic acid block copolymer.

[0099] Based on the total weight of the photopolymer adhesive composition, the composition may include 20% to 35%, preferably 25% to 35%, more preferably 28% to 32% of at least one block copolymer.

[0100] The term "(meth)acrylic acid block copolymer" refers to a (meth)acrylic acid 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 acid monomer based on the total weight of the copolymer. The non-(meth)acrylic acid monomer may be selected from the group consisting of butadiene, isoprene, styrene, vinylnaphthalene, cyclosiloxane monomers, vinylpyridine, and their derivatives (e.g., α-methylstyrene or tert-butylstyrene).

[0101] The block copolymer is selected from block copolymers comprising at least one M block and at least one B block, particularly block copolymers having a diblock BM structure (or a diblock copolymer BM) or a triblock MBM structure (or a triblock copolymer MBM), wherein each block is connected to each other by a covalent bond or by an intermediate molecule that is covalently connected to one of these blocks and covalently connected to another block by another block. The block copolymer is preferably a triblock copolymer MBM.

[0102] The M block refers to a polymer block containing at least 50% methyl methacrylate by weight. The M block may refer to a homopolymer block of polymethyl methacrylate (PMMA—100% methyl methacrylate by weight), or a copolymer block containing at least 50% methyl methacrylate by weight and 50% or less by weight of another monomer different from methyl methacrylate, all percentages being based on the total weight of the M block.

[0103] The B block refers to an elastic polymer block that is incompatible with the M block, and its glass transition temperature (Tg) is below 0°C, preferably below -20°C.

[0104] Regarding the diblock copolymer BM, the M block may be composed of methyl methacrylate monomer. Alternatively, based on the total weight of the M block, the M block may comprise at least 50% (e.g., 50% to 99.9%), preferably at least 75% (e.g., 75% to 99.9%) of methyl methacrylate; and 50% or less (e.g., 0.1% to 25%), preferably 25% or less (e.g., 0.1% to 25%) of at least one monomer different from methyl methacrylate.

[0105] Other monomers that constitute the M block, different from methyl methacrylate, may be another (meth)acrylic acid monomer or a non-(meth)acrylic acid monomer.

[0106] The non-(meth)acrylic acid monomer may be selected from the group consisting of butadiene, isoprene, styrene, naphthalene, cyclosiloxane monomers, vinylpyridine and its derivatives (e.g., α-methylstyrene or tert-butylstyrene).

[0107] The other (meth)acrylate monomer may be selected from the group consisting of: methyl acrylate, ethyl (meth)acrylate, (meth)acrylate, 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)acrylate (e.g., N,N-dimethylacrylamide), 2-methoxyethyl (meth)acrylate, 2-aminoethyl (meth)acrylate, polyethylene glycol (PEG) (meth)acrylate (wherein the molar mass of the PEG group ranges from 400 to 10,000 g / mol), and mixtures thereof.

[0108] The B-block of the elastomer may be composed of an alkyl (meth)acrylate monomer. Alternatively, the B-block may comprise: at least 95% (e.g., 95% to 99.9%) of an alkyl (meth)acrylate; and 5% or less (e.g., 0.1% to 5%) of another monomer different from the alkyl (meth)acrylate, the percentages being based on the total weight of the B-block.

[0109] The alkyl methacrylate may be selected from the group consisting of: ethyl acrylate (the homopolymer obtained after polymerization has a Tg of -24°C), butyl acrylate (the homopolymer obtained after polymerization has a glass transition temperature of -54°C), 2-ethylhexyl acrylate (the homopolymer obtained after polymerization has a Tg of -85°C), hydroxyethyl acrylate (the homopolymer obtained after polymerization has a Tg of -15°C), 2-ethylhexyl methacrylate (the homopolymer obtained after polymerization has a Tg of -10°C), and mixtures thereof; preferably, the alkyl methacrylate is butyl acrylate.

[0110] Other monomers, unlike alkyl (meth)acrylates, may be selected from the group consisting of: butadiene, isoprene, styrene, naphthalene, cyclosiloxane monomers, vinylpyridine and its derivatives (e.g., α-methylstyrene or tert-butylstyrene).

[0111] The diblock copolymer BM may have a number-average molecular weight in the range of 10,000 g / mol to 500,000 g / mol, preferably 20,000 g / mol to 200,000 g / mol.

[0112] The diblock copolymer BM may include: an M block comprising 5% to 95% by mass fraction (based on the total weight of the copolymer), preferably 15% to 85%; and a B block comprising 5% to 95% by mass fraction, preferably 15% to 85%.

[0113] Regarding the triblock copolymer MBM, its two M blocks are composed of the same monomers (or comonomers) as the M blocks in the diblock copolymer BM described above. These two M blocks may be the same or different. For example, the two M blocks may have different molecular weights but be composed of the same monomers.

[0114] The B block is composed of the same monomer (or comonomer) as the B block in the aforementioned binary block copolymer BM.

[0115] The triblock copolymer MBM may have a number-average molecular weight in the range of 10,000 g / mol to 500,000 g / mol, preferably 20,000 g / mol to 200,000 g / mol.

[0116] The triblock copolymer MBM may include: an M block with a mass fraction (based on the total weight of the copolymer) of 10% to 80%, preferably 15% to 70%, more preferably 40% to 60%; and a B block with a mass fraction of 20% to 90%, preferably 30% to 85%, more preferably 40% to 60%.

[0117] Preferably, the triblock copolymer MBM is a polymethyl methacrylate-poly(styrene-co-butyl acrylate)-polymethyl methacrylate block copolymer.

[0118] Block copolymers can be prepared by controlled radical polymerization (CRP) (e.g., according to the processes described in PCT applications WO 96 / 24620 A and WO 00 / 71501 A1) or anionic polymerization.

[0119] At most one of the M-blocks and B-blocks can be functionalized with a functional group selected from the group consisting of acids, amines, amides, epoxides, thiols, quaternary ammonium groups, chloride groups, and fluorinated groups.

[0120] The block copolymer is commercially available from Arkema under the trade name Nanostrength®.

[0121] Monoacrylate monomers

[0122] Relative to the total weight of the composition, the composition comprises: 45% to 75% by weight of a mixture P of (meth)acrylate monomers, wherein the homopolymer obtained after polymerization of the (meth)acrylate monomers has a glass transition temperature (Tg) of at least 85°C, the mixture P comprising at least one methacrylate monomer (the homopolymer obtained after polymerization of which has a glass transition temperature (Tg) of at least 85°C); and at least 5% by weight of a monoacrylate monomer, the homopolymer obtained after polymerization of which has a glass transition temperature (Tg) of at least 85°C.

[0123] The composition of the present invention preferably comprises 45% to 75%, more preferably 45% to 70%, and even more preferably 45% to 65% of a mixture P, wherein the percentages are based on the total weight of the composition.

[0124] Preferably, the mixture P comprises, by weight relative to the mixture P:

[0125] - 20% to 95%, more preferably 20% to 80%, even more preferably 30% to 70%, and most preferably 40% to 60% of methacrylate monomers, wherein the homopolymer obtained after polymerization has a glass transition temperature (Tg) of at least 85°C; and

[0126] - At least 5%, preferably at least 10%, more preferably 5% to 80%, more preferably 20% to 80%, even more preferably 30% to 70%, preferably 40% to 60% of monoacrylate monomers, the glass transition temperature (Tg) of the homopolymer obtained after polymerization is at least 85°C; preferably, the weight content of monoacrylate monomers in the mixture P should be such that the viscosity of the photopolymer adhesive composition obtained by the present invention reaches 100 mPa·s to 20,000 mPa·s, preferably 100 mPa·s to 10,000 mPa·s, more preferably 500 mPa·s to 5,000 mPa·s, and most preferably 1,000 mPa·s to 2,500 mPa·s. The viscosity can be measured according to standard NF EN 12092 "Adhesives—Viscosity determination" using a Brookfield DVIII Ultra viscometer (rotor: SC4-27, speed: 20 rpm, temperature: 25°C).

[0127] The methacrylate monomer (the glass transition temperature of the homopolymer obtained after polymerization is at least 85°C) may be selected 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, wherein the methacrylate with a glass transition temperature of at least 85°C after polymerization is preferably methyl methacrylate.

[0128] The monoacrylate monomer (the glass transition temperature of the homopolymer obtained after polymerization is at least 85°C) may be selected from the group consisting of isobornyl acrylate, dihydrodicyclopentadienyl acrylate and mixtures thereof, wherein the monoacrylate monomer with a glass transition temperature (Tg) of at least 85°C after polymerization is preferably isobornyl acrylate.

[0129] The mixture P further comprises at least one diacrylate monomer by weight of 0 to 40%, preferably 0 to 20% or 1 to 20%, more preferably 0 to 10% or 1 to 10% by weight, preferably 0 to 5% or 1 to 5% by weight, wherein the homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, particularly dipropylene glycol diacrylate (CAS No. 57472-68-1), neopentyl glycol hydroxyvalerate diacrylate (CAS No. 2136366-99-7), and tricyclodecanedimethanol diacrylate (CAS No. 52594-17-2), wherein the diacrylate monomer preferably having a glass transition temperature (Tg) of at least 85°C after polymerization is tricyclodecanedimethanol diacrylate (TCDDMDA).

[0130] Alkoxysilane (meth)acrylate monomers

[0131] The composition comprises at least one alkoxysilane (meth)acrylate monomer.

[0132] Based on the total weight of the composition, the composition may include 2 to 15%, preferably 3 to 10%, more preferably 4 to 6% of at least one alkoxy silane (meth)acrylate monomer.

[0133] The alkoxysilane (meth)acrylate monomer (including alkylalkoxysilane (meth)acrylate monomer) may be selected from the group consisting of trialkoxysilane (meth)acrylate monomer; preferably, it may be selected from the group consisting of trimethoxysilane (meth)acrylate monomer; wherein preferably, the alkoxysilane (meth)acrylate monomer is selected from the group consisting of 3-(trimethoxysilyl)propylacrylate, 3-(trimethoxysilyl)propylmethacrylate, trimethoxysilylacrylate, trimethoxysilylmethacrylate and mixtures thereof; wherein preferably, the alkoxysilane (meth)acrylate monomer is 3-(trimethoxysilyl)propylmethacrylate.

[0134] 3-(trimethoxysilyl)propyl methacrylate is available from Momentive® under the trade name Silquest® A174.

[0135] Photoinitiator

[0136] The composition includes at least one photoinitiator. Any compound capable of initiating the photopolymerization of the adhesive composition may be used, particularly any compound capable of initiating the free radical polymerization of (meth)acrylate polyurethane monomers and / or oligomers by ultraviolet (UV) or visible light irradiation to obtain the adhesive.

[0137] The composition may include 0.1% to 5%, preferably 0.5% to 4%, more preferably 1% to 3% of at least one photoinitiator based on the total weight of the composition.

[0138] The photoinitiator may be selected from the group consisting of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, triethylbenzoyl diphenylphosphine oxide, thiophene-9-one, 4,4-bis(diethylamino)benzophenone, 9,10-phenanthrenequinone, benzoyltrimethylgermane, dibenzoyldiethylgermane, bis-(4-methoxybenzoyl)diethylgermane, and mixtures thereof; preferably phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. For example, the mixture may include benzophenone, α-hydroxy ketone, and triethylbenzoyl diphenylphosphine oxide. Another mixture may include benzoyltrimethylgermane, dibenzoyldiethylgermane, and bis-(4-methoxybenzoyl)diethylgermane.

[0139] Phenylacetylbis(2,4,6-trimethylbenzoyl)phosphine oxide is commercially available from IGM Resins under the trade name Omnirad® 819 (formerly Irgacure® 819 from Ciba® Specialty Chemicals). A mixture of benzophenone, α-hydroxy ketone, and triethylbenzoyl diphenylphosphine oxide is commercially available from Lehvoss under the trade name Esacure® KTO 46.

[0140] Other (meth)acrylate monomers

[0141] The composition may include at least one (meth)acrylate monomer, the glass transition temperature (Tg) of which the homopolymer obtained after polymerization is below 0°C. In this embodiment, the composition includes a mixture of (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature of at least 85°C and (meth)acrylate monomers whose homopolymer obtained after polymerization has a glass transition temperature below 0°C.

[0142] The composition may include 0 to 5% by weight of at least one (meth)acrylate monomer, the glass transition temperature of which, after polymerization, forms a homopolymer with a glass transition temperature below 0°C. If present, the composition may include 0.1% to 5% by weight of at least one (meth)acrylate monomer, the glass transition temperature of which, after polymerization, forms a homopolymer with a glass transition temperature below 0°C.

[0143] The (meth)acrylate monomers of the homopolymer obtained after polymerization with a glass transition temperature below 0°C may be selected from the following group: 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.

[0144] Preferably, the composition may be substantially free of (meth)acrylate monomers whose glass transition temperature (Tg) of the resulting homopolymer is below 0°C.

[0145] methacrylic acid

[0146] The composition may include methacrylic acid monomer.

[0147] It should be understood that the methacrylic acid monomer is not the methacrylate in mixture P.

[0148] The composition may include 0 to 20% methacrylic acid by weight of the total composition. If present, the composition may include 1% to 16%, preferably 3% to 15%, methacrylic acid by weight of the total composition.

[0149] Preferably, the composition contains 5% to 12% methacrylic acid by weight of the total composition.

[0150] Polyurethane (meth)acrylate oligomers

[0151] The composition may include at least one polyurethane (meth)acrylate oligomer.

[0152] The composition may include 0 to 7% of at least one polyurethane (meth)acrylate oligomer based on the total weight of the composition. If present, the composition may include 0.1% to 7%, preferably 3% to 6%, of at least one polyurethane (meth)acrylate oligomer based on the total weight of the composition.

[0153] Preferably, the composition is substantially free of polyurethane (meth)acrylate oligomers.

[0154] The polyurethane (meth)acrylate oligomer can be selected from aliphatic polyurethane diacrylate oligomers, wherein the polyurethane (meth)acrylate oligomer is preferably aliphatic polyurethane diacrylate.

[0155] The composition may also include at least one monofunctional reactive diluent.

[0156] The composition may include 0 to 0.7% of at least one monofunctional reactive diluent by weight of the total composition. If present, the composition includes 0.1% to 0.7%, preferably 0.3% to 0.7% of at least one monofunctional reactive diluent by weight of the total composition.

[0157] The monofunctional reactive diluent may be 2-(2-ethoxyethoxy)ethyl acrylate. A mixture of polyurethane (meth)acrylate oligomers and monofunctional reactive diluents (comprising approximately 90% aliphatic polyurethane diacrylate and approximately 10% 2-(2-ethoxyethoxy)ethyl acrylate by weight of the composition) is commercially available from Sartamer under the trade name CN966H90®.

[0158] Viscosity

[0159] The photopolymer adhesive composition is preferably a liquid composition.

[0160] The viscosity of the composition can be from 100 mPa·s to 20,000 mPa·s, preferably from 100 mPa·s to 10,000 mPa·s, more preferably from 500 mPa·s to 5,000 mPa·s, and most preferably from 1,000 mPa·s to 2,500 mPa·s. The viscosity can be measured according to standard NF EN 12092 "Adhesives—Determination of viscosity" using a Brookfield DVIII ultraviscometer (rotor: SC4-27, rotation speed: 20 rpm, temperature: 25°C).

[0161] After polymerization, the glass transition temperature (Tg) of the composition is preferably at least 85°C, more preferably at least 90°C, and most preferably at least 100°C.

[0162] Preferably, the composition comprises (or consists of):

[0163] - At least one block copolymer; preferably at least one (meth)acrylate block copolymer; preferably a (meth)acrylate block copolymer having a triblock MBM structure;

[0164] - A mixture P of at least one (meth)acrylate monomer, wherein the homopolymer obtained after polymerization of the (meth)acrylate monomer has a glass transition temperature of at least 85°C, the mixture P comprising at least one methacrylate monomer, 5% (by weight of the total mixture P) of at least one monoacrylate monomer, and optionally 1% to 20% by weight of a diacrylate monomer, wherein the homopolymer obtained after polymerization of the methacrylate monomer has a glass transition temperature of at least 85°C and is selected 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, wherein the methyl... The preferred acrylate monomer is methyl methacrylate. The glass transition temperature (Tg) of the homopolymer obtained after polymerization of the monoacrylate monomer is at least 85°C and is selected from the group consisting of isobornyl acrylate, dihydrodicyclopentadienyl acrylate, and mixtures thereof. The monoacrylate monomer with a glass transition temperature (Tg) of at least 85°C after polymerization is preferably isobornyl acrylate. The glass transition temperature (Tg) of the homopolymer obtained after polymerization of the diacrylate monomer is at least 85°C. Preferably, the diacrylate monomer is selected from dipropylene glycol diacrylate, neopentyl glycol hydroxyvalerate diacrylate, and tricyclodecanediol diacrylate. The preferred diacrylate monomer is tricyclodecanediol diacrylate.

[0165] - At least one alkoxysilane (meth)acrylate monomer; preferably selected from trimekryl (meth)acrylate monomers, more preferably selected from trimethoxysilane (meth)acrylate monomers, and more preferably selected from the group consisting of 3-(trimethoxysilyl)propyl acrylate, 3-(trimethoxysilyl)propyl methacrylate, trimethoxysilyl acrylate, trimethoxysilyl methacrylate, and mixtures thereof; preferably, the monomer is 3-(trimethoxysilyl)propyl methacrylate;

[0166] - At least one photoinitiator; preferably, the photoinitiator is selected from the group consisting of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, triethylbenzoyl diphenylphosphine oxide, thiophene-9-one, 4,4-bis(diethylamino)benzophenone, 9,10-phenanthrolinequinone, benzoyltrimethylgermanium, dibenzoyldiethylgermanium, bis-(4-methoxybenzoyl)diethylgermanium and mixtures thereof; preferably, the photoinitiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and mixtures thereof.

[0167] - Optionally, at least one (meth)acrylate monomer, the homopolymer obtained after polymerization has a glass transition temperature below 0°C; preferably, the monomer is selected 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, the monomer is butyl acrylate.

[0168] - Optionally, methacrylic acid monomer;

[0169] - Optionally, at least one polyurethane (meth)acrylate oligomer; preferably, the oligomer is selected from aliphatic polyurethane diacrylate oligomers, and more preferably, the oligomer is aliphatic polyurethane diacrylate;

[0170] - Optionally, at least one monofunctional reactive diluent; preferably, the diluent is 2-(2-ethoxyethoxy)ethyl acrylate.

[0171] Preferably, the composition comprises (or consists of) the following, based on the total weight of the composition:

[0172] - 20% to 35%, preferably 25% to 35%, more preferably 28% to 32% of at least one block copolymer;

[0173] - A mixture P comprising 45% to 75%, preferably 45% to 70%, more preferably 45% to 65% of at least one (meth)acrylate monomer, wherein the homopolymer obtained after polymerization of the (meth)acrylate monomer has a glass transition temperature of at least 85°C, wherein the mixture P comprises: at least one methacrylate monomer, wherein the 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, more preferably 5% to 80% by weight, more preferably 20% to 80% by weight, most preferably 30% to 70% by weight of a monoacrylate monomer, wherein the homopolymer obtained after polymerization has a glass transition temperature of at least 85°C; and optionally, a diacrylate monomer, wherein the homopolymer obtained after polymerization has a glass transition temperature of at least 85°C;

[0174] - 2% to 15%, preferably 3% to 10%, more preferably 4% to 6% of at least one alkoxysilane (meth)acrylate monomer;

[0175] - At least one photoinitiator, comprising 0.1% to 5%, preferably 0.5% to 4%, more preferably 1% to 3%;

[0176] - 0 to 5% of at least one (meth)acrylate monomer, the glass transition temperature of the homopolymer obtained after polymerization is below 0°C;

[0177] - 0 to 20%, preferably 1 to 16%, more preferably 3 to 15% methacrylic acid; and

[0178] - 0 to 0.7% of at least one monofunctional reactive diluent.

[0179] Preferably, the composition comprises (or consists of) the following, based on the total weight of the composition:

[0180] - 20% to 35%, preferably 25% to 30%, of at least one block copolymer;

[0181] - A mixture P of 45% to 75%, preferably 45% to 70%, more preferably 45% to 65% of (meth)acrylate monomers, wherein the homopolymer obtained after polymerization of the (meth)acrylate monomers has a glass transition temperature of at least 85°C, wherein the mixture P comprises: at least one methacrylate monomer, wherein the 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, more preferably 5% to 80% by weight, more preferably 20% to 80% by weight, most preferably 30% to 70% by weight of monoacrylate monomers, wherein the homopolymer obtained after polymerization has a glass transition temperature of at least 85°C; and optionally, 0% to 40% by weight, preferably 1% to 20% by weight of diacrylate monomers, wherein the homopolymer obtained after polymerization has a glass transition temperature of at least 85°C;

[0182] - 2% to 15%, preferably 3% to 10%, more preferably 4% to 6% of at least one alkoxysilane (meth)acrylate monomer;

[0183] - At least one photoinitiator, comprising 0.1% to 5%, preferably 0.5% to 4%, more preferably 1% to 3%;

[0184] - 0 to 5% of at least one (meth)acrylate monomer, the homopolymer obtained after polymerization having a glass transition temperature below 0°C;

[0185] - 0 to 20%, preferably 1 to 16%, more preferably 3 to 15% methacrylic acid;

[0186] - 0 to 0.7% of at least one monofunctional reactive diluent.

[0187] Preferably, the composition comprises (or consists of) the following, based on the total weight of the composition:

[0188] - 25% to 35%, preferably 28% to 32%, of at least one block copolymer;

[0189] - A mixture P of 45% to 65% (meth)acrylate monomers, wherein the homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, wherein the mixture P comprises: 40% to 60% by weight of at least one methacrylate monomer, preferably methyl methacrylate, wherein the homopolymer obtained after polymerization has a glass transition temperature of at least 85°C; and at least 40% to 60% by weight of a monoacrylate monomer, wherein the homopolymer obtained after polymerization has a glass transition temperature of at least 85°C, preferably isobornyl acrylate or dihydrodicyclopentadienyl acrylate; and 0 to 10% by weight, preferably 0 to 5% by weight of a diacrylate monomer, preferably TCDDMDA, wherein the homopolymer obtained after polymerization has a glass transition temperature of at least 85°C;

[0190] - 3% to 10%, preferably 4% to 6%, of at least one alkoxysilane (meth)acrylate monomer, preferably trimethoxysilane methacrylate;

[0191] - At least one photoinitiator, at 0.5% to 4%, preferably 1% to 3%;

[0192] - 1% to 16%, preferably 3% to 15% methacrylic acid.

[0193] Preferably, the composition comprises (or consists of) the following, based on the total weight of the composition:

[0194] - 28% to 32% of at least one block copolymer;

[0195] - A mixture P of 45% to 65% (meth)acrylate monomers, wherein the homopolymer obtained after polymerization of the (meth)acrylate monomers has a glass transition temperature of at least 85°C, the mixture P comprising 40% to 60% methacrylate by weight, 40% to 60% preferred isobornyl acrylate by weight, and 0% to 5% TCDDMDA by weight.

[0196] - 4% to 6% of trimethoxysilane methacrylate, preferably 3-(trimethoxysilyl)propyl methacrylate;

[0197] - 1% to 3% of at least one photoinitiator;

[0198] - 3% to 15% methacrylic acid.

[0199] Single-component compositions

[0200] 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 containing at least two separately packaged components intended to be temporarily mixed together just before application of the thus obtained composition.

[0201] The one-component composition does not need to be prepared in the form of at least two separate components, nor does it need to be mixed just before use to avoid premature polymerization. In fact, the one-component composition contains at least one photoinitiator, making it possible to initiate polymerization once the composition is exposed to light (especially ultraviolet (UV) radiation). To avoid any premature or untimely polymerization, the composition should not be exposed to light.

[0202] Adhesive products

[0203] In a second aspect, the present invention relates to an adhesive product. The adhesive product comprises the above-described photopolymerizable adhesive composition and an opaque container containing the composition. The term "opaque container" refers to a container whose walls do not allow light (particularly visible light and ultraviolet radiation (wavelengths below 600 nm) capable of activating a photoinitiator to pass through.

[0204] The opaque container can be any container capable of containing the composition and maintaining its properties (particularly adhesive properties). Using an opaque container prevents the composition from being exposed to light (particularly ultraviolet radiation) before use (i.e., during storage and transportation), thereby avoiding any premature or untimely polymerization.

[0205] For example, the container may be a combination of a free bottle or a tube.

[0206] adhesives

[0207] In a third aspect, the present invention relates to an adhesive, particularly an adhesive obtained from the above-described photopolymerizable adhesive composition. The terms "adhesive" or "photopolymerizable adhesive composition" refer to an adhesive layer obtained by applying the photopolymerizable adhesive composition, photopolymerizing it, and optionally shaping the adhesive thus obtained.

[0208] The adhesive is obtained by a method comprising the following steps:

[0209] The aforementioned photopolymer adhesive composition is applied to at least one cover plate and / or electronic or optoelectronic device;

[0210] Photopolymerizing the photopolymer adhesive composition described above to obtain a polymerized adhesive; and

[0211] Optionally, the polymerized adhesive is shaped.

[0212] The adhesive may be in the form of a film.

[0213] The application of the composition can be achieved using conventional application techniques, such as: groove coating, deep groove coating, inkjet printing, screen printing, spin coating, spray coating, or using a doctor blade coater.

[0214] Photopolymerization of the composition can be achieved by exposure to ultraviolet (UV) radiation and visible light, notably using a UV lamp that emits light within a range that allows activation of the photoinitiator without being absorbed by the encapsulation cap. A suitable UV lamp, for example, could be the Delolix® 03S UV LED system. Photopolymerization can be achieved within 1 to 10 minutes.

[0215] The thickness of the adhesive can be from 10 μm to 200 μm, preferably from 10 μm to 100 μm, and more preferably from 10 μm to 30 μm.

[0216] The adhesive offers many advantages, particularly for use at temperatures of at least 70°C, preferably at least 85°C, for example when electronic or optoelectronic devices are photovoltaic cells, or when devices need to meet temperature testing standards (such as automotive applications).

[0217] Advantageously, for example when electronic or optoelectronic devices are photovoltaic cells, or when the device needs to meet temperature testing standards (such as automotive applications), the adhesive formulation according to the invention allows the use of encapsulated objects at temperatures up to at least 70°C, or even up to at least 85°C.

[0218] The adhesive preferably exhibits satisfactory adhesive properties, notably allowing satisfactory cohesion between the electronic or optoelectronic device and the cover plate, even for flexible modules.

[0219] The adhesive preferably exhibits satisfactory optical properties, particularly satisfactory transparency, notably allowing light waves to propagate to electronic or optoelectronic devices and / or limiting diffraction, especially when the device is a photovoltaic cell. The adhesive can have a transparency of 90% transmittance between 400 nm and 800 nm. Transparency can be measured using UV-Vis transmission spectroscopy.

[0220] The adhesive should preferably exhibit satisfactory electrical properties, particularly satisfactory electrical insulation properties, especially to prevent any short circuits within the module. Electrical insulation characteristics can be measured according to ASTM D149 standard.

[0221] The adhesive preferably exhibits satisfactory resistance, particularly to aging, abrasion and / or impact under ultraviolet radiation.

[0222] The adhesive preferably exhibits satisfactory barrier properties, particularly against water and oxygen (air). Barrier properties can be measured according to ASTM F1249 standards at 38°C and 85% relative humidity, with a water vapor transmission rate of less than 5 g·m³ for a thickness of 1 mm. 2 ·d -1 Preferred weight is less than 2 g·m 2 ·d -1 .

[0223] The adhesive preferably exhibits satisfactory elastic properties. Elastic properties (especially flexibility) can be measured using a cylindrical mandrel bending tester, a three-point or four-point "bending test" method, or a tensile measurement method.

[0224] Electronic or optoelectronic modules

[0225] In a fourth aspect, the present invention relates to a module, particularly a flexible module. The module corresponds to an encapsulated electronic or optoelectronic device.

[0226] The module can be obtained by stacking and assembling a series of layers. These layers may include, in turn:

[0227] First cover plate;

[0228] The first adhesive obtained as described above or the photopolymer adhesive composition as described above;

[0229] Flexible electronic or optoelectronic devices;

[0230] The second adhesive as described above or the second adhesive obtained from the photopolymer adhesive composition as described above; and

[0231] Second cover plate.

[0232] The electronic or optoelectronic device itself may include a semiconductor layer deposited on a supporting substrate.

[0233] The series of layers may also include additional layers, particularly layers between the cover plate and the adhesive, such as additional layers for improving the adhesion between the inner surface of the cover plate and the adhesive composition, surface treatment layers of the cover plate, etc.

[0234] In the resulting module, electronic or optoelectronic devices are preferably encapsulated by two overlapping adhesives around their periphery to form a tight seal. The encapsulation of the electronic or optoelectronic devices by the adhesives, and their encapsulation between the two cover plates, allows for isolation from the environment.

[0235] The resulting modules exhibit satisfactory characteristics, allowing for the limitation or even prevention of orthogonal and lateral penetration while maintaining the flexibility of electronic or optoelectronic devices.

[0236] The total thickness of the module can be from 50 μm to 500 μm, preferably from 50 μm to 300 μm, and more preferably from 50 μm to 150 μm.

[0237] The electronic or optoelectronic device may be selected from rigid devices, flexible devices, or combinations thereof; preferably, the device is a flexible device; preferably, the device is selected from organic light-emitting diodes, organic or perovskite photovoltaic cells, organic or perovskite transistors, or sensors, or combinations thereof.

[0238] In certain embodiments, photovoltaic cells employ perovskite devices. The crystal structure of so-called halide perovskite materials can include metals (e.g., lead or tin), organic and inorganic cations (e.g., cesium, formamide, and / or ammonium), and halide anions (e.g., boron or iodine). Perovskite devices are particularly suitable for photovoltaic applications. However, perovskite devices can exhibit stability issues over time due to their sensitivity to atmospheric conditions, especially water vapor.

[0239] The cover plates may be the same or different.

[0240] The cover plate can be single-layered or multi-layered.

[0241] The cover plate can be flexible or rigid, with flexible being preferred.

[0242] The module may be oriented, for example, comprising a lower or rear cover (commonly referred to as a "backing") and an upper or front cover (commonly referred to as a "front liner"). The upper or front cover is preferably transparent, and the lower or rear cover is preferably opaque.

[0243] Depending on the characteristics required by the electronic or optoelectronic devices and modules used, the cover plate may have specific properties.

[0244] The cover plate can be a polymer cover plate.

[0245] The cover plate can be an inorganic cover plate.

[0246] The polymer cover may include at least one layer of fluorinated polymer obtained from at least one fluorinated polymer, such as poly(vinyl fluoride) (PVF), poly(vinylidene fluoride) (PVDF), and mixtures thereof.

[0247] The polymer cover may include at least one polymer layer (or PET layer) made of polyethylene terephthalate (PET) and a fluorinated polymer layer.

[0248] Fluorinated polymer layers, PET layers and combinations thereof, and single or multilayer covers made therefrom are particularly suitable for use as bottom or rear covers.

[0249] The cover may include at least one layer of glass.

[0250] The cover may include at least one polymer layer (or PMMA layer) made of polymethyl methacrylate (PMMA). Glass or PMMA layers are particularly suitable for use as top or front covers.

[0251] Flexible cover plates, particularly suitable for encapsulating flexible electronic or optoelectronic devices (especially organic or perovskite solar cells), are commercially available from 3M® under the trade name 3M Ultra-Barrier Solar Film. These cover plates are laminated multilayer plates comprising: a PET film, silica, alumina, or an inorganic barrier layer of silicon nitride type 20 to 300 nm, a so-called PSA film (pressure-sensitive adhesive), and a fluoropolymer film or coating called a "weather-resistant layer" placed in external conditions to protect the entire environment.

[0252] Methods for obtaining electronic or optoelectronic modules

[0253] In a fifth aspect, the present invention relates to a method for obtaining the above-described module, the method comprising the following steps:

[0254] Provide electronic or optoelectronic devices;

[0255] Provide the photopolymer adhesive composition as described above;

[0256] Provide the first cover plate;

[0257] Provide a second cover plate;

[0258] The photopolymer adhesive composition is applied to the surface of the device and / or the corresponding inner surfaces of the first and second cover plates;

[0259] A layer of the device and the photopolymer adhesive composition is laminated between the respective inner surfaces of the first and second cover plates; and

[0260] The layer of the photopolymer adhesive composition is photopolymerized.

[0261] The method may also include a step of irradiating the first cover plate and / or the second cover plate with ultraviolet-ozone before the application step and / or the lamination step.

[0262] In a particular embodiment, rigid modules are obtained using vacuum lamination technology (referred to as a “sheet-to-sheet” process).

[0263] In another embodiment, the flexible module is fabricated using a continuous roll-to-roll process, as detailed in the paper titled "Research Progress: Large-Area Deposition, Coating, Printing and Processing Techniques for Scale-Up Perovskite Solar Cell Technology" published by S. Razza et al. in *Applied Physics Letters: Materials* (Vol. 4, No. 9, 2016). This technique is particularly suitable for flexible electronic or optoelectronic devices; preferably devices selected from organic light-emitting diodes, organic or perovskite photovoltaic cells, organic or perovskite transistors and sensors, or combinations thereof; perovskite devices are preferred.

[0264] Applications and uses

[0265] In a sixth aspect, the present invention relates to the use of the above-described photopolymer adhesive composition and the adhesive obtained therefrom for encapsulating electronic or optoelectronic devices (particularly for encapsulating flexible electronic or optoelectronic devices, such as for encapsulating organic photovoltaic devices, especially perovskite devices).

[0266] Example

[0267] The following examples are intended to illustrate the invention, but are not intended to limit it.

[0268] List of materials and equipment

[0269] Block copolymer: Triblock copolymer MBM [polymethyl methacrylate-poly(styrene-co-butyl acrylate)-polymethyl methacrylate block copolymer] (abbreviated as MBM), supplied by Arkema.

[0270] Methacrylate monomers, whose homopolymers obtained after polymerization have a glass transition temperature of at least 85°C: methyl methacrylate (MAM).

[0271] Monoacrylate monomers, whose homopolymers obtained after polymerization have a glass transition temperature of at least 85°C: isobornyl acrylate (abbreviated as: methyl methacrylate, IBOA).

[0272] Acrylic ester monomers, the homopolymers obtained after polymerization have a glass transition temperature of at least 85°C: tricyclodecanedimethanol diacrylate (TCDDMDA), supplied by Arkema.

[0273] Alkoxysilane (meth)acrylate monomer: 3-(trimethoxysilyl)propyl methacrylate (Momentive® Silquest® A174 product) (abbreviation: A174).

[0274] Photoinitiator: phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), available from Sigma-Aldrich.

[0275] Methacrylic acid (AMA)

[0276] Light source: Delolix® 03S UV LED system

[0277] Module under test

[0278] The module under test is usually referred to as the test sample.

[0279] PK layer: Surface area is 4×4cm (16cm²) 2 The perovskite layer, with the chemical formula Cs 0.05 FA 0.95 Pb(I 0.88 Br 0.12 )3

[0280] Glass layer: Surface area 5×5cm (25cm) 2 ) layer

[0281] ITO layer: Indium Tin Oxide Layer

[0282] The ITO glass layer itself forms the supporting substrate.

[0283] The PK layer was deposited using spin coating technology, while the top ITO layer was deposited using physical vapor deposition.

[0284] The perovskite layer is deposited on the support substrate, with a 5 mm gap between the edge of the substrate and the perovskite layer.

[0285] The module was encapsulated between two glass covers with a thickness of 1.2 mm using the photopolymer composition to be tested.

[0286] Test methods

[0287] Viscosity measurement

[0288] According to the requirements of standard NF EN 12092 "Adhesives - Determination of viscosity", the viscosity of the composition was determined using a Brookfield DVIII ultraviscometer (rotor: SC4-27, rotation speed: 20 rpm, temperature: 25°C).

[0289] Polymerization kinetics and conversion rate

[0290] The polymerization kinetics and final conversion of the photopolymerized composition were determined by real-time Fourier transform infrared spectroscopy (RT-FTIR). The composition to be characterized was deposited as a 300 μm thick film between two polypropylene films. The sample was placed in an RT-FTIR spectrophotometer, allowing for analysis at a wavelength of 395 nm and a power of 630 mW / cm². 2 The infrared absorption spectrum of the composition was continuously measured during irradiation under the light of a light-emitting diode (LED) lamp. Measurements of absorbance at a frequency of 6170 nm (corresponding to one of the characteristic infrared absorption peaks of the double bonds of the (meth)acrylate functional group) allowed monitoring of the monomer conversion over time (expressed as the percentage of moles of reacted double bonds relative to the initial number of double bonds). After several tens of seconds, this conversion reached a plateau value, representing the maximum conversion of the composition under these irradiation conditions. The conversion at time t (denoted as conversion (t)) was calculated using the following formula: Conversion (t) = (A0 - At) / (A0) × 100, where A0 and At are the absorbance at time t=0 and the considered time t, respectively. From this conversion curve related to irradiation time, the efficiency of the polymerization kinetics was 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 ln([M0] / [Mt]) as a function of time, where [M0] and [Mt] are the concentrations of (meth)acrylate groups at time t=0 and the considered time t, respectively. In this equation, kp corresponds to the propagation rate constant, and [P·] corresponds to the steady-state concentration of the propagating free radicals. Rp / [M0]×100 corresponds to the maximum slope of the conversion versus time curve. It is relative to the maximum polymerization rate. If the values ​​of kp, [P·], and Rp are high, then the system will be more efficient in terms of polymerization kinetics.

[0291] Thermal properties and gas barrier properties

[0292] The thermal properties of the tested module were analyzed using differential scanning calorimetry (DSC). Measurements were performed at a rate of 10 °C / min over three cooling-heating cycles ranging from -80 °C to 200 °C. In the third heating cycle, the glass transition temperature was measured using the tangential method at an intermediate height between 40 °C and 140 °C.

[0293] Gas barrier properties were determined by optical testing, which measured the degradation kinetics of the perovskite layer in the test samples. The degradation of the tested modules was evaluated using the following method: the test samples were placed in a climate chamber at 85°C and 85% relative humidity according to the climatic test conditions for photovoltaic modules reported in standard method IEC 61615 to determine the algorithm parameters for the degradation rate (cm² / h). Please refer to the papers titled "Perovskite Test: A high throughput method to screen ambient encapsulation conditions" published by E. Booker et al. in *Energy Technology* (Vol. 8, No. 12, 2020) and "A machine vision tool for facilitating the optimization of large area perovskite photovoltaics" published by N. Taherimakhsousi et al. in *npj Computational Materials* (Vol. 190, 2021), the latter of which describes the algorithm used in more detail. Photographic images of the test samples were taken periodically, for example, approximately every 48 hours, to assess the aging of the perovskite layer. In these tests, the area of ​​the "active" surface was measured, i.e., the area of ​​the perovskite (PK) layer with a thickness greater than the empirical threshold (180 nm). It is known that the initial thickness of the PK was 400 nm in all tests, and the initial area in all tests was approximately 14 cm². 2 Monitoring this area allows for measurement within 12cm. 2 and 3cm 2 The linear regression relationship established between them determines the VA parameter (layer degradation rate, in cm). 2 / h) and DA12 parameters ( Figure 3 ), that is, the DA12 parameter is the "active" surface reaching 12cm. 2 The time.

[0294] Monitoring the average thickness of the "active" surface allows for the determination of the VE parameter (thickness decay rate) and the DE380 parameter, obtained through linear regression established in the range of 340 nm to 230 nm. The DE380 parameter corresponds to the time point when the average thickness reaches 380 nm starting from 400 nm.

[0295] Photopolymer adhesive composition

[0296] The following photopolymerizable adhesive compositions were prepared (see Table 1, proportions expressed as weight percentages relative to the total weight of the photopolymerizable adhesive compositions):

[0297] Table 1

[0298]

[0299] Add 3g of photoinitiator BAPO per 100g of the composition described in Table 1.

[0300] CExA, CExB, and CExC are control group compositions. The compositions Ex1 and Ex2 of the present invention have viscosity levels compatible with the implementation method, i.e., viscosities between 200 cP and 10,000 cP. However, the viscosities of compositions CExA and CExB are too high, making them difficult to handle.

[0301] result

[0302] Kinetics and conversion rate

[0303] Table 2 below summarizes the kinetic and conversion data of the compositions of the present invention (Ex1 and Ex2) and the control composition (CExC). Each composition was tested twice.

[0304] Table 2

[0305]

[0306] Table 2 shows that formulations Ex1 and Ex2 have significantly higher polymerization efficiencies, with kp, [P·], and Rp values ​​all much higher than the control (CExC). Furthermore, the maximum conversion rates of Ex1 and Ex2 are also higher than those of CExC.

[0307] Vapor separator (Vapor barrier)

[0308] The degradation rates of multilayer modules obtained from compositions Ex1 and Ex2 of the present invention and control composition CExC were tested.

[0309] The test module takes pictures at regular intervals. Images are taken at 0h, 159h, 280h, 351h, 447h, 521h, 624h, 737h, 852h, 948h, and 1091h.

[0310] Several parameters were extracted from these images, namely:

[0311] ● The area of ​​the “active” surface ( Figure 1This area refers to the area of ​​a perovskite (PK) layer with a thickness greater than the empirical threshold (180 nm). It is known that the initial thickness of the PK in all tests was 400 nm, and the initial area of ​​the PK in all tests was approximately 14 cm². 2 .

[0312] o Monitor this area to utilize 12cm 2 and 3cm 2 The linear regression relationship established between them is used to determine the VA parameters. Figure 2 The VA parameters of these three formulations were observed to be similar.

[0313] The same area monitoring can also define DA12 parameters ( Figure 3 That is, the "active" surface reaches 12cm. 2 The time frame was measured. The DA12 levels of these three formulations were observed to be similar.

[0314] ● Monitor the average thickness of the "active" surface ( Figure 4 ):

[0315] o The VE parameters obtained by establishing a linear regression between 340nm and 230nm ( Figure 5 The composition of the present invention exhibits better vitamin E effect.

[0316] oDE380 parameters ( Figure 6 This corresponds to the time when the average thickness, starting from 400 nm, reaches 380 nm, at which point the values ​​of these three formulations are found to be very close.

[0317] Shrinkage

[0318] The polymerization linear shrinkage of the formulations from the three examples was determined. This measurement was performed using a Thermo Fisher Scientific Haake Mars 40 flat / flat panel apparatus at 286 MW / cm². 2 Photorheological tests were performed under mercury UV lamp irradiation, and the sample thickness (denoted as h) in the rheometer gap was monitored in real time at a shear rate of 0.01%. The temperature was stabilized at 25℃ for 120 s before the measurement began. The shrinkage rate was then calculated as the percentage shrinkage in the term h. The results are shown in Table 3 below.

[0319] Table 3

[0320]

[0321] The compositions of the present invention are therefore able to significantly reduce shrinkage.

Claims

1. A photopolymerizable adhesive composition comprising, based on the total weight of the photopolymerizable adhesive composition: 20% to 35% of at least one block copolymer, preferably a (meth)acrylic block copolymer, 45% to 75% of a mixture P of (meth)acrylate monomers, the homopolymer resulting upon polymerization of said (meth)acrylate monomers having a glass transition temperature (Tg) of at least 85°C, said mixture P comprising at least one methacrylate monomer, the homopolymer resulting upon polymerization of said methacrylate monomer having a glass transition temperature (Tg) of at least 85°C, and at least 5% by weight of a monoacrylate monomer, the homopolymer resulting upon polymerization of said monoacrylate monomer having a glass transition temperature (Tg) of at least 85°C; 2% to 15% of at least one alkoxysilane (meth)acrylate monomer; and 0.1% to 5% of at least one photoinitiator.

2. The photopolymer adhesive composition according to claim 1, wherein, said block copolymer is selected from the group consisting of block copolymers of at least one M block and at least one B block; said M block refers to a polymeric block comprising at least 50% by weight of methyl methacrylate; and said B block refers to an elastomeric polymeric block incompatible with said M block, said elastomeric polymeric block having a glass transition temperature (Tg) lower than 20°C.

3. The photopolymer adhesive composition according to any one of the preceding claims, wherein, said mixture P comprises at least one methacrylate monomer, the homopolymer resulting upon polymerization of said methacrylate monomer having a glass transition temperature of at least 85°C, said methacrylate monomer being selected from the group consisting of methyl methacrylate, t-butyl methacrylate, phenyl methacrylate, isopropyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, 4-t-butylcyclohexyl methacrylate and mixtures thereof, wherein preferably said methacrylate monomer is methyl methacrylate, and at least 5% by weight, relative to the total weight of said mixture P, of a monoacrylate monomer, the homopolymer resulting upon polymerization of said monoacrylate monomer having a glass transition temperature (Tg) of at least 85°C, said monoacrylate monomer being selected from the group consisting of isobornyl acrylate, dihydrosbornyl acrylate and mixtures thereof, wherein preferably said monoacrylate monomer is isobornyl acrylate, the homopolymer resulting upon polymerization of said monoacrylate monomer having a glass transition temperature (Tg) of at least 85°C.

4. The photopolymer adhesive composition according to any one of the preceding claims, wherein, said mixture P further comprises at least one diacrylate monomer, the homopolymer resulting upon polymerization of said diacrylate monomer having a glass transition temperature (Tg) of at least 85°C, wherein preferably said diacrylate monomer is selected from the group consisting of di(propylene glycol) diacrylate, neopentyl glycol hydroxypivalate diacrylate, tricyclodecane dimethanol diacrylate, wherein preferably said diacrylate monomer is tricyclodecane dimethanol diacrylate (TCDDMDA), the homopolymer resulting upon polymerization of said diacrylate monomer having a glass transition temperature of at least 85°C.

5. The photopolymer adhesive composition according to any one of the preceding claims, wherein, said mixture P comprises: - at least 20% by weight, more preferably 20% to 80% by weight, even more preferably 30% to 70% by weight, preferably 40% to 60% by weight, relative to the weight of the mixture P, of at least one methacrylate monomer, the homopolymer resulting after polymerization of said methacrylate monomer having a glass transition temperature (Tg) of at least 85°C; - at least 5% by weight, preferably at least 10% by weight, more preferably 5% to 80% by weight, more preferably 20% to 80% by weight, even more preferably 30% to 70% by weight, preferably 40% to 60% by weight, of a monoacrylate monomer, the homopolymer resulting after polymerization of said monoacrylate monomer having a glass transition temperature (Tg) of at least 85°C; and - at least 1% to 20% by weight, more preferably 1% to 10% by weight, preferably at least 1% to 5% by weight, of at least one diacrylate monomer, the homopolymer resulting after polymerization of said diacrylate monomer having a glass transition temperature of at least 85°C.

6. The photopolymer adhesive composition according to any one of the preceding claims, wherein, The alkoxysilane (meth)acrylate monomer is selected from the group consisting of trialkoxysilane (meth)acrylate monomers.

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

8. The photopolymerizable adhesive composition according to any one of the preceding claims, comprising and preferably consisting of, by total weight of the composition: - 28% to 32% of at least one block copolymer; - 45% to 65% of a mixture P of (meth)acrylate monomers, the homopolymer obtained after polymerization of said (meth)acrylate monomers having a glass transition temperature of at least 85°C, said mixture P comprising 40% to 60% by weight of methyl methacrylate, 40% to 60% by weight of isobornyl acrylate, preferably, and 0 to 5% by weight of TCDDMDA; - 4% to 6% of trimethoxysilane methacrylate; - 1% to 3% of at least one photoinitiator; - 3% to 15% of methacrylic acid.

9. The photopolymer adhesive composition according to any one of the preceding claims, wherein, The photopolymerizable adhesive composition is a one-component composition.

10. The photopolymer adhesive composition according to any one of the preceding claims, wherein, The photopolymerizable adhesive composition has a glass transition temperature of at least 85°C, preferably at least 90°C, more preferably at least 100°C, after polymerization.

11. An adhesive product comprising the photopolymerizable adhesive composition according to any one of the preceding claims and an opaque container containing said composition.

12. An adhesive obtained by a process comprising the steps of: applying the photopolymerizable adhesive composition according to any one of claims 1 to 10 on at least one cover plate and / or electronic or optoelectronic device; subjecting the applied photopolymerizable adhesive composition to photopolymerization to obtain a polymerized adhesive; and optionally, shaping the polymerized adhesive.

13. An electronic or optoelectronic module comprising a series of layers assembled in the following order: a first cover plate; a first adhesive according to claim 12 or obtained from the photopolymerizable adhesive composition according to any 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 any one of claims 1 to 10; and a second cover plate.

14. The electronic or optoelectronic module of claim 13, wherein, The flexible electronic or optoelectronic device is selected from an organic light emitting diode, an organic photovoltaic cell, an organic transistor, or an organic sensor, or a combination thereof.

15. The electronic or optoelectronic module according to any of claims 13 or 14, wherein, The flexible electronic or optoelectronic device is a perovskite type device.

16. A method of obtaining the module according to any one of claims 13 to 15, said method comprising the steps of: providing an electronic or optoelectronic device; providing the photopolymerizable adhesive composition according to any one of claims 1 to 10; providing a first cover plate; providing a second cover plate; applying a layer of the photopolymerizable adhesive composition on the surface of the device and / or on the respective inner surfaces of the first and second cover plates; laminating the device with the layer of the photopolymerizable adhesive composition between the respective inner surfaces of the first and second cover plates; and subjecting the layer of the photopolymerizable adhesive composition to photopolymerization.

17. Use of the photopolymerizable adhesive composition according to claims 1 to 10 or of the adhesive according to claim 11 or 12 for encapsulating a flexible electronic or optoelectronic device.

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