Composition comprising at least one organic peroxide and at least one carbonate

Abstract

The present invention deals with an organic peroxide-based composition, in particular a composition comprising at least one organic peroxide and at least one carbonate, as defined below, suitable for the polymerization and curing of systems containing at least one unsaturated monomer, as well as the crosslinking of at least one crosslinkable polymer, in various applications for instance in the field of renewable energies.

Description

[0001] Description

[0002] Title : COMPOSITION COMPRISING AT LEAST ONE ORGANIC PEROXIDE AND AT LEAST ONE CARBONATE

[0003] Field of the invention

[0004] The present invention deals with an organic peroxide-based composition, in particular a composition comprising at least one organic peroxide and at least one carbonate, as defined below, suitable for the polymerization and curing of systems containing at least one unsaturated monomer, as well as the crosslinking of at least one crosslinkable polymer, in various applications for instance in the field of renewable energies.

[0005] The instant invention also pertains to a crosslinkable composition comprising at least one crosslinkable polymer, preferably chosen from polyolefin elastomers, at least one organic peroxide and at least one carbonate, as defined herein below.

[0006] The invention further relates to polymerizable composition comprising at least one unsaturated monomer, especially chosen from vinyl monomers and / or acrylate monomers, at least one organic peroxide and at least one carbonate, as defined herein below.

[0007] Background of the invention

[0008] Organic peroxide-based compositions can be used for the polymerization of at least one unsaturated monomer, such as vinyl monomers and / or acrylate monomers, and / or the crosslinking of at least one crosslinkable polymer, such as ethylene-vinyl acetate (EVA) copolymers and / or polyolefin elastomers (POE), in various applications, for example in the field of renewable energies, namely to improve efficiency and costs of systems capable of producing energy from renewable resources, such as photovoltaic modules (also known as solar panels or collectors) producing electrical energy from solar energy, and energy storage systems.

[0009] Indeed, in the field of photovoltaic modules, photovoltaic cells (also known as solar cells) are electrically connected to one another (in series or in parallel) and are encapsulated in such a way as to ensure their electrical insulation and protection against external environmental factors, such as humidity, weathering such as rain or snow, and ultraviolet radiations.

[0010] The materials, preferably in film form, used to encapsulate photovoltaic cells are commonly based on polyolefins, such as ethylene-vinyl acetate (EVA) copolymers and / or polyolefin elastomers (POE).

[0011] To achieve satisfactory thermomechanical properties for this application, particularly in terms of good adhesion properties to the module substrate, creepresistance and weather resistance, it is important to crosslink the polyolefins and obtain a good crosslinking density. Indeed, if the cross-linking density is too low, the resulting material is likely to have insufficient tensile strength and tear resistance, among other things.

[0012] The crosslinking agents typically used are organic peroxides such as dialkyl peroxides, peroxyesters, peroxyketals, peroxycarbonates and mixtures thereof. As an example of monoperoxycarbonates, it is already known to use OO-tert-butyl-O-(2-ethylhexyl)monoperoxy carbonate (TBEC) for crosslinking polyolefins, in particular for crosslinking ethylene-vinyl acetate copolymers (EVA) and elastomeric polyolefins (POE).

[0013] During the encapsulation process of solar cells, rapid and low-temperature crosslinking reactions are generally sought to effectively protect the sensitivity of solar cells, guaranteeing their performance and longevity, and reduce energy consumption and production costs, thus improving overall production efficiency and product quality.

[0014] Furthermore, in the field of renewable energies, specifically in the energy storage systems, the use of organic peroxide-based compositions capable of initiating polymerization more rapidly at the lowest possible temperatures is also sought after to improve efficiency and save costs.

[0015] Current methods generally implemented to enhance crosslinking of crosslinkable polymers and / or polymerization reactions, especially to increase their rate and / or lower their temperature at which they occur, can involve using highly active peroxide compound blends or redox initial systems.

[0016] However, the use of highly active organic peroxide mixtures may present stability issues or be too reactive to lead to satisfactory cross-linking and / or polymerization reactions in many applications. For instance, the implementation of highly organic peroxide mixtures can lead to premature crosslinking (scorching) of the polymer while it is still in the granulate state or during shaping, especially during extrusion, resulting in the formation of gel particles causing imperfections (inhomogeneity or surface roughness) in the final product. Excessive scorching reduces the plastic properties of the product, so that it can no longer be processed, resulting in the loss of the entire batch. Excessive scorching can also bring the extrusion process to a complete halt.

[0017] Moreover, redox initial systems rely on the use of additional promoters, such as amines and transition metals, to accelerate the decomposition of organic peroxides and enhance their reactivity, thereby increasing crosslinking and / or polymerization reactions rates under mild conditions without energy consumption, especially without any thermal or light activation.

[0018] Yet these redox initial systems may also exhibit a myriad of issues in various applications. For example, the toxicity of these additional promoters, such as aromatic amines, is proving to be a major concern in the food industry, particularly in thedevelopment of food contact materials or food contacting substances (FCS). In the field of optics, some accelerators, such as amines in acrylate-containing compositions, are prone to yellowing which can lead to colours issues in the final product. In the electronic field, some accelerators can alter the electronical performances of the final product.

[0019] It bespeaks that the use of redox initial systems based on a mixture of organic peroxides and accelerators for curing crosslinkable polymers may alter the colours and / or the performances of the resulting cured composition. On top of that, as far as radical polymerization is concerned, the polymerization rate can become uncontrollable when redox initial systems are used, leading to the risk of runaway reactions.

[0020] As a result, it remains a real need to provide an organic peroxide-based composition capable of increasing the rate of crosslinking and / or polymerization reactions at the lowest possible temperatures without encountering the above-mentioned shortcomings, in particular which is storage-stable and offers a stable processing window to allow satisfactory cross-linking and / or polymerization under good conditions, while minimizing the risks of runaway reactions, and without affecting the quality and / or the performances of the resulting product.

[0021] In other words, one of the purposes of the present invention is to provide an organic peroxide-based composition capable of enhancing crosslinking performances (crosslinking speed and crosslinking density) and / or polymerization reactions in various applications, particularly in the field of renewable energies, specifically in the solar field.

[0022] More specifically, one of the goals of the present invention is to implement an organic peroxide-based composition which alleviates the above-mentioned drawbacks, and which can be used in systems capable of producing energy based on solar energy, such as photovoltaic modules, or in energy storage systems.

[0023] Description of the invention

[0024] The present invention namely results from the unexpected findings, by the inventors, that an organic peroxide-based composition comprising at least one organic peroxide (OP) and at least one compound (CP), as defined hereafter, can achieve the goals previously mentioned.

[0025] Therefore, the present invention relates to a composition comprising:

[0026] at least one organic peroxide selected in the group consisting of:

[0027] o formula (I-a):

[0028] RI-O-O-C(=O)-R2(I-a)

[0029] Formula (I-a) wherein:

[0030] Ri represents an alkyl group R’ i or an ester group -C(=O)O-R’ i, wherein R’ i is a saturated linear or branched C3-C9 alkyl group or an aromatic group having from 3 to 9 carbon atoms,R.2 represents an alkyl group R’2 or an alkoxy group -OR’ 2, wherein R’2 represents a saturated linear or branched C3-C30 alkyl group, preferably a C3-C10 alkyl group;

[0031] o formula (I-b):

[0032] C-[{CR}y-[-O-R7-]x-O-C(O)-O-O-R8]4(I-b)

[0033] Formula (I-b) wherein:

[0034] - R is H or an aliphatic saturated alkyl group comprising less than or 8 carbon atoms;

[0035] - R7 represents a C2-C10 alkene group,

[0036] - R8is selected in the group consisting of: C1-C10 alkyl group, C3-C10 cycloalkyl group and Ce-Cis aryl group,

[0037] - x et y independently represent an integer from 1 to 10;

[0038] o and mixtures thereof,

[0039] preferably the at least one organic peroxide is of formula (la) as defined above,

[0040] at least one compound selected in the group consisting of:

[0041] o formula (Il-a):

[0042] [Chem 1]

[0043] II

[0044] R3-O-C-(O)R4

[0045]

[0046] Formula (Il-a) wherein:

[0047] R3 and R4 may form together a ring of at most three carbon atoms which may substituted with one or more halogen atoms and / or one or more C1-C4 alkyl groups;

[0048] o formula (Il-b)

[0049] R3O-0-(C=0) -R4O (II-b)

[0050] Formula (II-b) wherein:

[0051] R30 represents an alkyl group R’30 ,

[0052] R40 represents an alkyl group R’40 or an alkoxy group -OR’ 40, wherein R’30 and R’40, identical or different, represent:

[0053] - an aliphatic saturated linear or branched alkyl group comprising less than or 8 carbon atoms, which may be substituted by at least one aromatic group having from 5 to 8 carbon atoms, preferably by at least one benzene ring, or- an aromatic group having from 3 to 9 carbon atoms;

[0054] o and mixtures thereof

[0055] wherein the molar ratio between said at least one organic peroxide to said at least one compound of formula (II) ranges from 0.01 to 30, preferably ranges from 0.05 to 10, more preferably 0.1 to 6.

[0056] The composition according to the present invention thus exhibits a high reactivity, as it enables the rates of polymerization and / or crosslinking reactions to be increased and the temperatures at which they occur to be lowered, which can be an asset in a variety of applications.

[0057] In other words, the composition of the present invention at the desired time brings about crosslinking and / or polymerization, preferably crosslinking, at the lowest possible temperatures and at high speed.

[0058] The composition according to the present invention has further the advantage of being storage-stable and offering a stable processing window to enable cross-linking and / or polymerization to take place under good conditions, while minimizing the risks of runaway reactions, without altering the quality and / or the performances of the resulting product.

[0059] Hence, the composition of the invention allows for better control over the curing and / or the polymerization rate. In other words, reactions, including curing and / or polymerization reactions, initiated with the composition of the instant invention are easier to manage and monitor than with compositions traditionally used in the prior art, particularly compositions comprising highly active peroxide compound blends or redox initiator systems.

[0060] Consequently, the use of this composition can improve the overall efficiency of a process comprising at least one curing and / or polymerization step, which can lead to costs savings and reduced energy consumption in various technical fields.

[0061] Advantageously, said at least one compound of formula (II) offers high compatibility with said at least one organic peroxide of formula (I-a) or (I-b), preferably (I-a), which enables not only to reduce the stability issues commonly associated with organic peroxides but also promote the reactivity of said organic peroxides.

[0062] Hence, the instant composition can be stored and transported especially at room temperature.

[0063] Therefore, the composition of the instant invention can be advantageously used for the polymerization and curing (or vulcanization) of systems containing at least one unsaturated monomer, especially chosen from vinyl monomers and / or acrylate monomers, as well as the cross-linking of crosslinkable polymer, preferably chosen elastomeric polyolefins (POE), more preferably from rubber and ethyl ene-butene copolymers.

[0064] Furthermore, the composition of instant invention enables minimizing the risks of premature crosslinking (scorching) of crosslinkable polymers, preferably chosenfrom elastomeric polyolefins (POE), namely ethylene-vinyl acetate copolymers (EVA) and ethyl ene-butene copolymers.

[0065] In other words, said composition makes it possible to retard scorching during the crosslinking of polymeric compositions, without impeding the curing time and / or the crosslinking density, thereby ensuring the quality and / or the properties of the resulting cured compositions.

[0066] Moreover, the composition of the present invention can be used in various technical fields, including in the field of renewable energies, specifically in the solar field.

[0067] Advantageously, the composition of the present invention can be used for the polymerization and curing of systems containing at least one unsaturated monomer, as well as the crosslinking of at least one crosslinkable polymer, in particular for ensuring the performances and the longevity of systems capable of producing energy based on solar energy, such as photovoltaic modules.

[0068] Still advantageously, said composition can also be used for the polymerization and curing of systems containing at least one unsaturated monomer, as well as the crosslinking of at least one crosslinkable polymer, to reduce energy consumption and production costs in such technical fields.

[0069] Another subject-matter of the present invention relates to the use of said at least one composition, as previously defined, for crosslinking at least one crosslinkable polymer, preferably chosen among the group consisting of polyolefins elastomers, more preferably chosen among the group consisting of ethylene-vinyl acetate copolymers (EVA), ethyl ene-butene copolymers and rubbers.

[0070] Advantageously, the use of said at least one composition allows to rein in the risks of scorching of at least one crosslinkable polymer and affords to control its curing.

[0071] The instant invention further pertains to the use of said at least one composition, as previously defined, for polymerizing and / or curing systems containing at least one unsaturated monomer, preferably chosen from the group consisting of vinyl monomers and / or acrylate monomers.

[0072] Advantageously, the use of said at least one composition allows to accelerate the polymerization of containing at least one unsaturated monomer without triggering runaway reactions and while minimizing the generation of by-products.

[0073] The instant invention also pertains to a crosslinkable composition comprising at least one crosslinkable polymer, preferably chosen from polyolefin elastomers, and at least one composition as previously defined.

[0074] Another aspect of the present invention relies upon the use of said at least one crosslinkable composition for producing at least one system capable of producing energy based on solar energy, preferably at least one photovoltaic module.The invention further relates to polymerizable composition comprising at least one unsaturated monomer, especially chosen from vinyl monomers and / or acrylate monomers, and at least one composition as previously defined.

[0075] Other subjects and characteristics, aspects and advantages of the invention will emerge even more clearly on reading the description and the examples that follow.

[0076] In the text herein below, and unless otherwise indicated, the limits of a range of values are included in that range, in particular in the expressions “between” and “ranging from...to...”.

[0077] Moreover, the expression “at least one” used in the present description is equivalent to the expression “one or more”.

[0078] In the text herein below, the terms “alkene” and “alcene” are equivalent. Furthermore, the term “polymer” encompasses “homopolymers” and “copolymers”, where the term “copolymers” refers to a polymer comprised of at least two different monomers in polymerized form. For example, a copolymer in accordance with the present disclosure may be a polymer comprising two different monomers, a terpolymer is a polymer comprising three different monomers or more.

[0079] Composition

[0080] Organic peroxide according to formula (I) (i.e. (I -a) or (I -b)

[0081] As previously detailed, the composition comprises at least one organic peroxide selected in the group consisting of:

[0082] o formula (I-a):

[0083] RI-O-O-C(=O)-R2(I-a)

[0084] Formula (I-a) wherein:

[0085] Ri represents an alkyl group R’ i or an ester group -C(=O)O-R’ i, wherein R’ i is a saturated linear or branched C3-C9 alkyl group or an aromatic group having from 3 to 9 carbon atoms,

[0086] R2 represents an alkyl group R’2 or an alkoxy group -OR’ 2 wherein R’2 represents a saturated linear or branched C3-C30 alkyl group, preferably a C3-C10 alkyl group;

[0087] o formula (I-b) :

[0088] C-[{CR}y-[-O-R7-]x-O-C(O)-O-O-R8]4 (I-b)

[0089] Formula (I-b) wherein:

[0090] - R is H or an aliphatic saturated alkyl group comprising less than or 8 carbon atoms;- R? represents a C2-C10 alkene group

[0091] - Rs is selected in the group consisting of: C1-C10 alkyl group, C3-C10 cycloalkyl group and Ce-Cis aryl group,

[0092] - x et y independently represent an integer from 1 to 10;

[0093] o and mixtures thereof,

[0094] preferably the at least one organic peroxide is of formula (la) as defined above.

[0095] Preferably, in formula (I-a), R1 represents an aliphatic saturated linear or branched, preferably branched, C3-C9 alkyl group.

[0096] Preferably, in formula (I-a), R2 represents an alkoxy group -OR’ 2 wherein R’2 represents a saturated linear or branched, preferably branched, C3-C10 alkyl group

[0097] According to a preferred embodiment, in formula (I-a):

[0098] • Ri represents an aliphatic saturated linear or branched, preferably branched, C3-C9 alkyl group, and

[0099] • R2 represents an alkoxy group -OR’ 2 wherein R’2 represents a saturated linear or branched, preferably branched, C3-C10 alkyl group wherein the molar ratio between said at least one organic peroxide to said at least one compound of formula (II) ranges from 0.01 to 30, preferably ranges from 0.05 to 10, more preferably, 0.06 to 8, most preferably 0.1 to 6.

[0100] Preferably, in formula (I-a), Ri represents an aliphatic saturated linear or branched, preferably branched, C4-C9 alkyl group, and R2 represents an alkoxy group -OR’2 wherein R’2 represents a saturated linear or branched, C3-C9 alkyl group.

[0101] Preferably, in formula (I-a), Ri represents an aliphatic saturated branched, C4-C9 alkyl group and R2 represents an alkoxy group -OR’2 wherein R’2 represents a saturated branched, C3-C9 alkyl group.

[0102] Said at least one organic peroxide (OP) of formula (I-a) or (I-b) is preferably chosen among the group consisting of tert-butylperoxy 2-ethylhexyl carbonate (TBEC), OO-tert-amyl-O-2-ethylhexyl monoperoxycarbonate (TAEC), tert-butylisopropyl monoperoxycarbonate (TBIC), tert-amy isopropyl monoperoxycarbonate (TAIC), polyether poly-tert-butylperoxycarbonate (JWEB), tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy -2-ethylhexanoate, tert-butyl peroxy isobutyrate, tert-butyl peroxy -3, 5, 5 -trimethylhexanoate, tert-amyl peroxy-3, 5, 5 -trimethylhexanoate, di-2-ethylhexylpercarbonate, and mixtures thereof, preferably chosen among the group consisting of tert-butylperoxy 2-ethylhexyl carbonate, OO-tert-amyl-O-2-ethylhexyl monoperoxycarbonate, tert-butylisopropyl monoperoxycarbonate, tert-amy isopropyl monoperoxy carbonate, polyether poly-tert-butylperoxycarbonate, and mixtures thereof, preferably chosen among the group consisting of tert-butylperoxy 2-ethylhexylcarbonate, OO-tert-amyl-O-2-ethylhexyl monoperoxycarbonate, tert-butylisopropyl monoperoxycarbonate, tert-amy isopropyl monoperoxycarbonate, and mixtures thereof, and most preferably among the group consisting of tert-butylperoxy 2-ethylhexyl carbonate, OO-tert-amyl-O-2-ethylhexyl monoperoxycarbonate and mixtures thereof.

[0103] Said at least one organic peroxide (OP) according to formula (I-a) and / or (I-b) has a 1 -minute half-life temperature (HLT) of at least 90°C, preferably of at least 120°C, more preferably of at least 140°C.

[0104] Preferably, said at least one organic peroxide (OP) according to formula (I-a) and / or (I-b) has a 1 -minute HLT ranging from 90°C to 170°C, preferably ranging from 140°C to 170°C.

[0105] The term "1 -minute HLT" represents the temperature at which half of the organic peroxide has decomposed in a given time of one minute. Conventionally, the "one minute half-life temperature" is measured in n-dodecane.

[0106] Said at least one organic peroxide (OP) according to formula (I-a) and / or (I-b) may be present at a content ranging from 20% to 99.9% by weight, preferably ranging from 30% to 99.9% by weight, for example ranging from 40% to 99.9% by weight, for example ranging from 50% to 99.9% by weight relative to the total weight of said composition. For example, said at least one organic peroxide (OP) according to formula (I) may be present at a content of 30%, 33%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90% by weight relative to the total weight of said composition.

[0107] Compound (CP) according to formula (Il-a) or (Il-b)

[0108] The composition further comprises at least one compound (CP) corresponding to formula (ILa) or (Il-b) :

[0109] [Chem 1]

[0110]

[0111] Formula (ILa) wherein:

[0112] R3 and R4 may form together a ring of at most three carbon atoms which may substituted with one or more halogen atoms and / or one or more C1-C4 alkyl groups;

[0113] R3O-0-(C=0)-R4O (Il-b)

[0114] Formula (Il-b) wherein:

[0115] R30 represents an alkyl group R’30,

[0116] R40 represents an alkyl group R’40 or an alkoxy group -OR’ 40,wherein R’30 and R’40, identical or different, represent:

[0117] - an aliphatic saturated linear or branched alkyl group comprising less than 8 carbon atoms or 8 carbon atoms, preferably a saturated linear alkyl group comprising less than 8 carbon atoms or 8 carbon atoms, which may be substituted by at least one aromatic group having from 5 to 8 carbon atoms, preferably by at least one benzene ring, or

[0118] - an aromatic group having from 3 to 9 carbon atoms.

[0119] According to a preferred embodiment, in formula (Il-b) :

[0120] • R30 represents an alkyl group R’30,

[0121] • R40 represents an alkyl group R’40 or an alkoxy group -OR’ 40,

[0122] o wherein R’30 and R’40, identical or different, represent:

[0123] - an aliphatic saturated linear or branched, preferably linear, alkyl group comprising less than 8 carbon atoms or 8 carbon atoms, which may be substituted by at least one aromatic group having from 5 to 8 carbon atoms, preferably by at least one benzene ring, or

[0124] - an aromatic group having from 3 to 9 carbon atoms, preferably at least one benzene ring.

[0125] According to a preferred embodiment, in formula (Il-b) :

[0126] • R30 represents an alkyl group R’30,

[0127] • R40 represents an alkoxy group -OR’ 40,

[0128] o wherein R’30 and R’40, identical or different, represent

[0129] - an aliphatic saturated linear or branched, preferably linear, alkyl group comprising less than 8 carbon atoms or 8 carbon atoms which may be substituted by at least one aromatic group having from 5 to 8 carbon atoms, preferably by at least one benzene ring, or

[0130] - an aromatic group having from 3 to 9 carbon atoms, preferably at least one benzene ring.

[0131] Preferably, in formula (Il-b), R’30 and R’40, identical or different, represent an aliphatic saturated linear or branched alkyl group, preferably a linear alkyl group, comprising less than 4 carbon atoms or 4 carbon atoms, more preferably represent a saturated linear alkyl group comprising less than 4 carbon atoms or 4 carbon atoms.

[0132] Preferably, in formula (Il-b), R’30 and R’40 are identical and represent an aliphatic saturated linear or branched alkyl group comprising less than 8 carbon atoms or 8 carbon atoms, more preferably, R’30 and R’40 are identical and represent a saturated linear or branched alkyl group comprising less than 8 carbon atoms or 8 carbon atoms.

[0133] Preferably, in formula (Il-b), R’30 and R’40 are identical and represent an aliphatic saturated linear or branched alkyl group, preferably a linear alkyl group, comprising less than 4 carbon atoms or 4 carbon atoms.

[0134] According to a preferred embodiment, in formula (Il-b) :

[0135] • R30 represents an alkyl group R’30,• R40 represents an alkoxy group -OR’40,

[0136] o wherein R’30 and R’40 are identical and represent an aliphatic saturated linear or branched, preferably linear, alkyl group comprising less than 4 carbon atoms or 4 carbon atoms.

[0137] Preferably, in formula (Il-a), R3 and R4 form together a ring of at most three carbon atoms which may be substituted with one or more halogen atoms chosen from the group consisting of fluorine atom bromine atom, one or more C1-C4 alkyl groups, preferably one or more C1-C2 alkyl groups, and mixture thereof.

[0138] Advantageously, compound (CP) corresponds to formula (Il-a) wherein R3 and R4 may form together a ring of at most three carbon atoms which may be substituted with one or more C1-C4 alkyl groups, preferably one or more C1-C2 alkyl groups.

[0139] Said at least one compound (CP) of formula (Il-a) or formula (Il-b) may have a boiling point higher than 50°C, preferably higher than or equal to 70°C, more preferably higher than or equal to 100°C, even better higher than or equal to 140°C.

[0140] According to a preferred embodiment, said at least one compound (CP) of formula (Il-a) or formula (Il-b) has a boiling point ranging from 50°C to 350°C, preferably ranging from 70°C to 300°C, more preferably from 100°C to 270°C, even more preferably from 140°C to 270°C.

[0141] Said at least one compound of formula (Il-a) or (Il-b) may be chosen among the group consisting of methyl acetate, ethyl acetate, methyl propionate, dimethyl carbonate, ethyl propionate, propyl acetate, ethyl methyl carbonate, diethyl carbonate, trimethylene carbonate, dipropyl carbonate, fluoroethylene carbonate, dibutyl carbonate, bromoethylene carbonate, propylene carbonate, chloroethylene carbonate, butylene carbonate, ethylene carbonate, propyl phenyl acetate, diphenyl carbonate, ethyl acetate, dimethyl carbonate and mixture thereof, preferably chosen among the group consisting of ethyl methyl carbonate, diethyl carbonate, trimethylene carbonate, dipropyl carbonate, fluoroethylene carbonate, dibutyl carbonate, bromoethylene carbonate, propylene carbonate, chloroethylene carbonate, butylene carbonate, ethylene carbonate, diphenyl carbonate, ethyl acetate, dimethyl carbonate and mixture thereof, more preferably among the group consisting of ethyl methyl carbonate, diethyl carbonate, trimethylene carbonate, dipropyl carbonate, dibutyl carbonate, propylene carbonate, butylene carbonate, ethylene carbonate, diphenyl carbonate, ethyl acetate, dimethyl carbonate and mixture thereof, and even more preferably among the group consisting of ethylene carbonate, dimethyl carbonate, ethyl acetate, propylene carbonate and mixtures thereof, and even more preferabley is ethylene carbonate.

[0142] Said at least one compound (CP) of formula (Il-a) or (Il-b) may be present at a total content ranging from 0.1 to 80% by weight, preferably ranging from 0.1 to 70% by weight, for example ranging from 0.1 to 50% by weight, relative to the total weight of said composition. For example, said at least one compound (CP) of formula (Il-a) or (II-b) may be present at a content of 5%, 9%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 67%, or 70% by weight.

[0143] For example, the molar ratio between said at least one organic peroxide of formula (I) (formula (I-a) and / or (I-b)) to said at least one compound of formula (II) ranges from 0.01 to 30, preferably ranges from 0.05 to 10, more preferably 0.1 to 6, for example 0.05, 0.06, 0.08, 0.1, 0.17, 0.3, 0.4, 0.5, 1, 1.5., 2. 2.5, 3, 3.5, 4, 5, 6, 8, 10, 12, 15, 20, 25 or 30.

[0144] Preferably, the weight ratio of said at least one organic peroxide of formula (I) (formula (I-a) and / or formula(I-b)) to said at least one compound of formula (II) ranges from 0.005 to 50, preferably from 0.01 to 30, and even preferably from 0.1 to 20, for example 0.005, 0.01, 0.03, 0.05, 0.1, 0.5, 0.9. 1, 5, 10, 15, 20, 25 or 30.

[0145] Composition comprising at least two organic peroxide of formula (I-a) or (I-b)

[0146] The composition of the invention may comprise at least two organic peroxide of formula (I-a) or (I-b), different from each other, preferably said second organic peroxide corresponding to formula (III).

[0147] Preferably, the composition of the invention comprises comprising at least one organic peroxide of formula (I-a), and at least a second organic peroxide corresponding to formula (III), said second organic peroxide being different from the first organic peroxide:

[0148] [Chem 2]

[0149] O

[0150] R5_ O— O -U— R6

[0151] (HI)

[0152] Formula (III) wherein

[0153] Rs represents an aliphatic saturated linear or branched C3-C9 alkyl group or an aromatic group having from 3 to 9 carbon atoms,

[0154] Re represents an aliphatic saturated linear or branched C3-C10 alkyl group. Preferably, said at least one composition comprises at least one organic peroxide corresponding to formula (III).

[0155] According to a preferred embodiment, in formula (III):

[0156] • R5 represents an aliphatic saturated linear or branched C3-C9 alkyl group, preferably C5-C9 alkyl group,

[0157] • Re represents an aliphatic saturated linear or branched C3-C10 alkyl group, preferably C5-C10 alkyl group.

[0158] Preferably, in formula (III), Rs represents an aliphatic saturated branched C3-C9 alkyl group and Re represents an aliphatic saturated branched C3-C10 alkyl group, more preferably an aliphatic saturated branched C5-C10 alkyl group.Said at least one organic peroxide of formula (III) may be chosen among the group consisting of tert-butyl-peroxy-2-ehtylhexanoate, tert-amyl-peroxy-2-ethylhexanoate, tert-butyl peroxybenzoate, tert-amyl peroxybenzoate, tert-butyl peroxy-3.5.5 -trimethylhexanoate, tert-amyl peroxy-3.5.5 -trimethylhexanoate, tert-butyl peroxy-3.5.5 -trimethylhexanoate, tert-butyl peroxyisobutyrate, and mixtures thereof.

[0159] Said at least one organic peroxide (OP) according to formula (I-a) and / or (I-b) may be present at a content ranging from 30 to 100% by weight, e.g., at a content ranging from 30 to 90% by weight, like 40%, 50%, 60, 70%, 80%, 90%, 95% relative to the total weight of the organic peroxides present in said composition.

[0160] Preferably, in the composition as defined above, the weight ratio of said at least two organic peroxide of formula (I-a) and / or (I-b) to said at least one compound of formula (II), ranges from 0.005 to 50, preferably from 0.01 to 30, and even preferably from 0.1 to 20, for example 0.005, 0.01, 0.03, 0.05, 0.1, 0.5, 0.9. 1, 5, 10, 15, 20, 25 or 30.

[0161] In a preferable embodiment, the composition of the invention comprises at least two organic peroxide of formula (I-a) or (I-b),

[0162] the first organic peroxide corresponding to formula (I-a)

[0163] R1-O-O-C(=O)-R2 (I-a)

[0164] wherein Ri represents an aliphatic saturated branched C4-C9 alkyl group and R2 represents an alkoxy group -OR’ 2 wherein R’2 represents a saturated branched C3-C9 alkyl group,

[0165] and a second organic peroxide corresponding to formula (III) as above mentioned.

[0166] Said the first organic peroxide may be present at a content ranging from 30 to 100% by weight, e.g., at a content ranging from 30 to 90% by weight, like 40%, 50%, 60, 70%, 80%, 90%, 95% relative to the total weight of the organic peroxides present in said composition.

[0167] The composition may be prepared by mixing said at least one organic peroxide of formula (I-a) and / or (I-b) as previously described and said at least one compound (CP) of formula (Il-a) or (Il-b), as previously defined, according to any conventional methods.

[0168] Use

[0169] The present invention further relates to the use of composition comprising: at least one organic peroxide selected in the group consisting of:

[0170] o formula (I-a):

[0171] RI-O-O-C(=O)-R2(I-a)Formula (I-a) wherein:

[0172] Ri represents an alkyl group R’ i or an ester group -C(=O)O-R’ i, wherein R’ i is a saturated linear or branched C3-C9 alkyl group or an aromatic group having from 3 to 9 carbon atoms,

[0173] R2 represents an alkyl group R’2 or an alkoxy group -OR’ 2 wherein R’2 represents a saturated linear or branched C3-C30 alkyl group, preferably a C3-C10 alkyl group;

[0174] o formula (I-b):

[0175] C-[{CR}y-[-O-R7-]x-O-C(O)-O-O-R8]4(I-b)

[0176] Formula (I-b) wherein:

[0177] - R is H or an aliphatic saturated alkyl group comprising less than or 8 carbon atoms;

[0178] - R7 represents a C2-C10 alkene group

[0179] - R8is selected in the group consisting of: C1-C10 alkyl group, C3-C10 cycloalkyl group and Ce-Cis aryl group,

[0180] - x et y independently represent an integer from 1 to 10;

[0181] o and mixtures thereof,

[0182] preferably the at least one organic peroxide is of formula (la) as defined above,

[0183] at least one compound selected in the group consisting of:

[0184] o formula (Il-a):

[0185] [Chem 1]

[0186] O II

[0187] R3-O-C-(O)R4

[0188]

[0189] x- S (ILa)

[0190] Formula (Il-a) wherein:

[0191] R3 and R4 may form together a ring of at most three carbon atoms which may substituted with one or more halogen atoms and / or one or more C1-C4 alkyl groups;

[0192] o formula (Il-b)

[0193] R3O-0-(C=0) -R4O (II-b)

[0194] Formula (II-b) wherein:

[0195] R30 represents an alkyl group R’30 ,

[0196] R40 represents an alkyl group R’40 or an alkoxy group -OR’ 40, wherein R’30 and R’40, identical or different, represent:- an aliphatic saturated linear or branched alkyl group comprising less than or 8 carbon atoms, which may be substituted by at least one aromatic group having from 5 to 8 carbon atoms, preferably by at least one benzene ring, or

[0197] - an aromatic group having from 3 to 9 carbon atoms;

[0198] o and mixtures thereof

[0199] for crosslinking at least one crosslinkable polymer, preferably at least one polyolefin elastomer.

[0200] Preferably, the composition is as previously defined in the “Composition” section.

[0201] Preferably, the present invention relates to the use the composition as previously defined, for crosslinking at least one crosslinkable polymer, preferably at least one polyolefin elastomer.

[0202] Preferably, the composition according to the present invention comprises at least one crosslinkable polymer, preferably at least one polyolefin elastomer.

[0203] A “polyolefin” in the sense of the present invention refers to a polymer derived from an olefin, for example ethylene, propylene, butene, hexene, etc.

[0204] For the purposes of this invention, the term “derived from” means that the units of the main chain of the polymer and / or of the adjacent chains (or pendant chains) of the polymer result from polymerization or copolymerization of the monomers from which the polymer is made.

[0205] For the purposes of this invention, “elastomeric polyolefin” (POE) means an elastomeric polymer derived from an olefin, e.g. ethylene, propylene, butene, hexene, etc.

[0206] For the purposes of this invention, “elastomer” is taken to mean a polymer capable of undergoing uniaxial deformation at room temperature, preferably by at least 20% for a period of fifteen minutes, and of returning to its initial shape, preferably with a residual deformation of less than 5% compared with its initial shape, when this stress is no longer exerted.

[0207] Elastomeric polymers used according to the invention can be defined as natural or synthetic polymers which have an elastomeric character and which can be crosslinked (cured) under the action of a crosslinking agent. In Rubber World, “Elastomer Crosslinking with Diperoxyketals”, October 1983, pages 26-32, and in Rubber and Plastic News, “Organic Peroxides for Rubber Crosslinking”, September 29, 1980, pages 46-50, the crosslinking action and crosslinkable polymers are described. Polyolefins suitable for the present invention are described in Modem Plastics Encyclopedia 89, pages 63-67, 74-75.The polyolefin elastomers may be chosen from the group consisting of low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyvinyl butyral (PVB), ethyl ene-propylene-diene terpolymers (EPDM), ethylene-vinyl acetate copolymers (EVA), ethyl ene-propylene copolymers, ethyl ene-butene copolymers, in particular ethylene- 1 -butene copolymers, ethyl ene-octene copolymers, in particular ethylene- 1 -octene copolymers, silicone rubber, natural rubber (NR), polyisoprene (IR), polybutadiene (BR), acrylonitrile-butadiene copolymers (NBR), styrene-butadiene copolymers (SBR), chlorosulfonated polyethylene or fluoroelastomers, ethylene-methyl (meth)acrylate copolymers, ethylene-glycidyl methacrylate copolymers, styrene-butadiene-styrene block copolymer (SBS), and mixtures thereof.

[0208] Preferably, the crosslinkable polymers are selected from the group consisting of polyethylene, ethylene-vinyl acetate copolymers (EVA), ethyl ene-butene copolymers, polyethylene, rubber, ethyl ene-propylene-diene terpolymers (EPDM), styrene-butadiene-styrene block copolymer (SBS) and mixtures thereof, more preferably selected from the group consisting of ethyl ene-butene copolymers, ethylenevinyl acetate copolymers (EVA) and rubber, more preferably ethyl ene-butene copolymers and rubber.

[0209] According to an embodiment, the crosslinkable polymers are ethylene-vinyl acetate copolymers (EVA) having a molar VA content of iV I8%, preferably a VA content of 20% - 40%. These copolymers possess low modulus, high resilience, and a rubber-like state at room temperature, and can be classified as polyolefin elastomers.

[0210] According to a preferred embodiment, said at least one composition is used for accelerating crosslinking of at least one crosslinkable polymer, as previously defined, preferably chosen among the group consisting of ethyl ene-butene copolymers, ethylenevinyl acetate copolymers (EVA) and rubber, more preferably ethyl ene-butene copolymers and rubber.

[0211] Another subject-matter of the instant invention is directed to the use of said at least one composition, as previously defined, for polymerizing and / or curing (or vulcanization) systems containing at least one unsaturated monomer, preferably chosen from the group consisting of vinyl monomers and / or acrylate monomers.

[0212] According to a preferred embodiment, said at least one composition is used for accelerating the polymerization of at least one unsaturated monomer, preferably chosen from the group consisting of vinyl monomers and / or acrylate monomers.

[0213] Said at least one composition may be advantageously used in the field of renewable energies, specifically in the solar field.

[0214] Crosslinkable composition

[0215] The instant invention pertains to a crosslinkable composition comprising at least one crosslinkable polymer as previously defined and for crosslinking at least one crosslinkable polymer and a composition comprising:at least one organic peroxide selected in the group consisting of:

[0216] o formula (I-a):

[0217] RI-O-O-C(=O)-R2(I-a)

[0218] Formula (I-a) wherein:

[0219] Ri represents an alkyl group R’ i or an ester group -C(=O)O-R’ i, wherein R’ i is a saturated linear or branched C3-C9 alkyl group or an aromatic group having from 3 to 9 carbon atoms,

[0220] R2 represents an alkyl group R’2 or an alkoxy group -OR’ 2 wherein R’2 represents a saturated linear or branched C3-C30 alkyl group, preferably a C3-C10 alkyl group;

[0221] o formula (I-b):

[0222] C-[{CR}y-[-O-R7-]x-O-C(O)-O-O-R8]4(I-b)

[0223] Formula (I-b) wherein:

[0224] - R is H or an aliphatic saturated alkyl group comprising less than or 8 carbon atoms;

[0225] - R7 represents a C2-C10 alkene group

[0226] - R8is selected in the group consisting of: C1-C10 alkyl group, C3-C10 cycloalkyl group and Ce-Cis aryl group,

[0227] - x et y independently represent an integer from 1 to 10;

[0228] o and mixtures thereof,

[0229] preferably the at least one organic peroxide is of formula (la) as defined above,

[0230] at least one compound selected in the group consisting of:

[0231] o formula (Il-a):

[0232] [Chem 1]

[0233] O II

[0234] R3-O-C-(O)R4

[0235]

[0236] x- S (ILa)

[0237] Formula (Il-a) wherein:

[0238] R3 and R4 may form together a ring of at most three carbon atoms which may substituted with one or more halogen atoms and / or one or more C1-C4 alkyl groups;

[0239] o formula (Il-b)R3O-0-(C=0) -R4O (II-b)

[0240] Formula (II-b) wherein:

[0241] R30 represents an alkyl group R’30 ,

[0242] R40 represents an alkyl group R’40 or an alkoxy group -OR’ 40, wherein R’30 and R’40, identical or different, represent:

[0243] - an aliphatic saturated linear or branched alkyl group comprising less than or 8 carbon atoms, which may be substituted by at least one aromatic group having from 5 to 8 carbon atoms, preferably by at least one benzene ring, or

[0244] - an aromatic group having from 3 to 9 carbon atoms;

[0245] o and mixtures thereof.

[0246] Preferably, said composition is as previously defined.

[0247] Said at least one composition as previously defined, may be present in a content ranging from 0.1 to 20% by weight, preferably from 0.1 to 10% by weight, more preferably in a content ranging from 0.1 to 5% by weight, more preferably in a content ranging from 0.1 to 2% by weight, relative to the total weight of the crosslinkable composition.

[0248] The crosslinkable composition of the instant invention may further comprise at least one coagent, which is not an organic peroxide, and which is different from compound of formula (Il-a) or (II-b).

[0249] Said at least one coagent advantageously comprises at least one carbamate, maleimide, acrylate, methacrylate, or allyl functional group. Allyl carboxylates may be used, and may be selected from the group consisting of allyl, diallyl, and triallyl types.

[0250] Said at least one coagent may be selected from the group consisting of divinylbenzene, diisopropenylbenzene, alpha-methylstyrene, alpha-methylstyrene dimer, ethylene glycol dimethacrylate, phenylene dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol 200 dimethacrylate, polyethylene glycol 400 dimethacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,12-dodecanediol dimethacrylate, glycerol 1,3-dimethacrylate, diurethane dimethacrylate, trimethylolpropane trimethacrylate, bisphenol A epoxy diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polyethylene glycol 600 diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, neopentyl glycol ethoxylate diacrylate, butanediol diacrylate, hexanediol diacrylate, aliphatic urethane diacrylate, trimethylolpropane triacrylate, trimethylolpropane ethoxylate triacrylate, trimethylolpropane propoxylate triacrylate, glycerol propoxylate triacrylate, aliphatic urethane triacrylate, trimethylolpropane triacrylate and dipentaerythritol pentaacrylate,triallyl cyanurate (TAC), triallyl isocyanurate, N,N'-m-phenylenedimaleimide, butadiene, chloroprene, isoprene, and mixture thereof.

[0251] More preferably, said at least one coagent is selected from the group consisting of the following: triallyl cyanurate, triallyl isocyanurate, N,N'-m-phenylenedimaleimide, triallyl trimellitate, trimethylolpropane triacrylate, and trimethylolpropane trimethacrylate, and preferably is selected from the group consisting of the following: triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), trimethylolpropane triacrylate (TMPTA), and trimethylolpropane trimethacrylate (TMPTMA), and more preferably still is triallyl isocyanurate.

[0252] Said at least one coagent may represent from 0.05% to 30%, preferably from 0.1% to 10%, by weight, relative to the total weight of the composition.

[0253] The principal objective of using a coagent is to increase the crosslinking rate of the crosslinkable composition. This coagent also enables a reduction in residual gas emission during the decomposition of said peroxides, and ultimately a reduction in the number of bubbles in the encapsulating material.

[0254] The crosslinkable composition may comprise:

[0255] 100 phr of at least one crosslinkable polymer, preferably chosen from crosslinkable rubber and / or polyolefin elastomers,

[0256] 0.3 to 5 phr of said at least one composition as previously defined, 0 to 10 phr of at least one additive agent as defined below.

[0257] Advantageously, said at least one crosslinkable composition is used for producing a system capable of producing energy based on solar energy, preferably at least one photovoltaic module.

[0258] According to one aspect of the instant invention, said at least one crosslinkable composition is used in the encapsulation process of solar cells in a photovoltaic module.

[0259] Polymerizable composition

[0260] Furthermore, the present invention deals with a polymerizable composition comprising at least one unsaturated monomer, preferably chosen from the group consisting of vinyl monomers and / or acrylate monomers, and at least one composition as previously defined.

[0261] Said at least one composition as previously defined, may be present in a content ranging from 0.1 to 20% by weight, preferably from 0.1 to 10% by weight, more preferably in a content ranging from 0.1 to 5% by weight, more preferably in a content ranging from 0.1 to 3% by weight, relative to the total weight of the polymerizable composition.

[0262] The polymerizable composition may comprise:

[0263] - 2% to 50% by weight of at least one unsaturated monomer, preferably from 10% to 50% by weight of at least one unsaturated monomer, preferably chosen from the group consisting of vinyl monomers and / or acrylate monomers- 50% to 98% of the composition as previously defined, preferably from 50% to 90% by weight of at least one unsaturated monomer.

[0264] Additives

[0265] The crosslinkable / polymerizable composition according to the present invention may further comprise one or more additive agents such as coupling agents, UV stabilizers, UV absorbers, UV to visible light conversion agents, fillers, plasticizers, flame retardants, antioxidants, additives that prevent Potential Induced Degradation (PID), dyes, organic or mineral pigments, and mixtures thereof. Examples of coupling agents are monoalkyl titanates, (vinyl)trichlorosilanes, and (vinyl)trialkoxysilanes.

[0266] The UV stabilizers may be selected from hindered amine light stabilizers (HALS), while the UV absorbers may be selected, for example, from benzophenones, triazines, and benzotriazoles.

[0267] Inorganic fillers such as silicon dioxide, alumina, talc, and calcium carbonate may be added to enhance the mechanical strength, although nanometric clays are preferred on account of the transparency they confer.

[0268] Organic or mineral pigments may also be added for colouring the composition. Mention may be made in particular of titanium dioxide, making it possible to produce a white colour, which is particularly useful when the composition is employed for manufacturing a film which is used at the rear face of photovoltaic panels.

[0269] Examples of plasticizers are paraffinic or aromatic mineral oils, phthalates, azelates, adipates, and the like.

[0270] The antioxidants may be phenolic, phosphate, or sulfur antioxidants. As a variant, quinolines such as l,2-dihydro-2,2,4-trimethylquinoline may be used as antioxidants.

[0271] The present invention will now be described in detail below by way of nonlimiting examples.

[0272] Examples

[0273] Two comparative compositions (Al) and (A2) and seven compositions (Bl)-(B7) according to the present invention are prepared with the ingredients indicated in Table 1 below. All the compositions included 0.5 phr of triallyl isocyanurate (TAIC, from Aladdin®) and 0.3 phr of 3-methacryloxy-propyltrimethoxysiloxane (KH570, XIAMETER® OFS-6030 Silane from Dow). The concentrations are indicated in phr.[Table 1]

[0274] Samples Al A2 Bl B2 B3 B4 B5 B6 B7 Polymer POE POE POE EVA POE POE POE POE POE Organic Lup26 TBEC Lup26 Lup26 TBEC TBEC TBEC TBEC TBEC Peroxides / (0.75) / / (0.75) (0.75) (0.75) (0.75) (0.75) (phr) TAEC TAEC TAEC

[0275] (1 / 9) (1 / 9) (0.6)

[0276] (0.75) (0.75)

[0277] Compound 0 0 EC EC EC EC EC DMC EA (0.75) (0.6) (0.75) (0.075) (1.5) (0.75) (0.75) of formula

[0278] (H)

[0279] (Phr)

[0280] Weight 1 1 1 10 0.5 1 1 Ratio

[0281] compound

[0282] (I) /

[0283] formula

[0284] (II)

[0285] Molecular — — 0.35 0.35 0.4 3.6 0.2 0.4 0.4 ratio

[0286] Compound

[0287] (I) /

[0288] formula

[0289]

[0290] (II) _

[0291] Table 1 : Compositions

[0292] • Lup 26 : tert-butyl-peroxy-2-ethylhexanoate (Luperox® 26) according to formula (III)(HLT (lmin)=129°C)

[0293] • TAEC : tert-amylperoxy 2-ethylhexyl carbonate (Luperox® TAEC) according to formula (I) (HLT(lmin)=155 °C)

[0294] • TBEC : tert-butylperoxy 2-ethylhexyl carbonate (Luperox® TBEC) according to formula (I) (HLT(1 min)=166°C)

[0295] • EC : Ethylene carbonate ; DMC : dimethyl carbonate ; EA : ethyl acetate from Aladdin®

[0296] • POE: ethylene- 1 -butene copolymer sold under the name LF575®

[0297] • EVA: ethylene vinyl acetate copolymer sold under the name EVA V2825 are used as the base resin in particles form.The compositions were prepared in a Haake internal mixer at a temperature of 35°C for a duration of 15 minutes, using a stirring speed of 50 rpm. The polymer blend is then passed through an open mill set at a temperature of 25°C to produce sheets approximately 2 mm thick. Samples of approximately 2 to 3 grams of the above compositions are placed in a plate on a rubber process analyser RPA 2000 ® which is capable of measuring the curing properties of the samples and includes software to analyze the results. Each sample is placed in a temperature-controlled cavity between two dies, with the lower die oscillating to apply cyclic stress or strain to the sample while the upper die is connected to a torque sensor to measure the sample's torque response to the deformation. Stiffness is continuously recorded over time. The stiffness of the sample increases as vulcanization occurs. This device is capable of providing, among other things, calculated values of ML (minimum torque), MH (maximum torque), and T90 (time to achieve 90% of total crosslink density) as defined by international standards (ASTM D5289 and ISO 6502). Crosslink density is directly defined by the difference between maximum torque MH and minimum torque ML and is expressed in dN.m. The RPA is operated at a temperature of 145°C with an oscillation amplitude (degree of deformation) of 0.5° applied to the sample for 30 minutes.

[0298] Results:

[0299] The results are displayed in table 2 below. In this table:

[0300] [Table 2]

[0301] Table 2: Results

[0302] Sample MH-ML Tc90

[0303] (dN.ni / s) (s)

[0304] Al 1.14 1726

[0305] A2 4.77 1163

[0306] Bl 1.50 1704

[0307] B2 2.53 781

[0308] B3 5.02 1074

[0309] B4 4.96 1069

[0310] B5 4.79 1066

[0311] B6 4.97 1072

[0312]

[0313] B7 4.77 1088Conclusion

[0314] The result show that the presence of a compound according to formula (Il-a) or (Il-b) accelerate the crosslinking reaction at different temperatures, while improving the crosslinking density.

Claims

Claims1. A composition comprising:at least one organic peroxide selected in the group consisting of:o formula (I-a):RI-O-O-C(=O)-R2(I-a)Formula (I-a) wherein:Ri represents an alkyl group R’ i or an ester group -C(=O)O-R’ i, wherein R’ i is a saturated linear or branched C3-C9 alkyl group or an aromatic group having from 3 to 9 carbon atoms,R2 represents an alkyl group R’2 or an alkoxy group -OR’ 2 wherein R’2 represents a saturated linear or branched C3-C30 alkyl group, preferably a C3-C10 alkyl group;o formula (I-b):C-[{CR}y-[-O-R7-]x-O-C(O)-O-O-R8]4(I-b)Formula (I-b) wherein:- R is H or an aliphatic saturated alkyl group comprising less than or 8 carbon atoms;- R7 represents a C2-C10 alkene group,- R8is selected in the group consisting of: C1-C10 alkyl group, C3-C10 cycloalkyl group and Ce-Cis aryl group,- x et y independently represent an integer from 1 to 10;o and mixtures thereof,preferably the at least one organic peroxide is of formula (la) as defined above,at least one compound selected in the group consisting of:o formula (Il-a):[Chem 1]IIR3-O-C-(O)R4Formula (Il-a) wherein:R3 and R4 may form together a ring of at most three carbon atoms which may substituted with one or more halogen atoms and / or one or more C1-C4 alkyl groups;o formula (Il-b)R3O-0-(C=0) -R4O (H-b)Formula (Il-b) wherein:R30 represents an alkyl group R’30 ,R40 represents an alkyl group R’40 or an alkoxy group -OR’ 40, wherein R’30 and R’40, identical or different, represent:- an aliphatic saturated linear or branched alkyl group comprising less than or 8 carbon atoms, which may be substituted by at least one aromatic group having from 5 to 8 carbon atoms, preferably by at least one benzene ring, or- an aromatic group having from 3 to 9 carbon atoms;o and mixtures thereofwherein the molar ratio between said at least one organic peroxide of formula (I-a) and / or (I-b) to said at least one compound of formula (II) ranges from 0.01 to 30, preferably ranges from 0.05 to 10, more preferably, 0.06 to 8, most preferably 0.1 to 6.

2. The composition according to claim 1, wherein said at least one organic peroxide of formula (I-a) and / or (I-b) has a 1 -minute half-life temperature (HLT) of at least 90°C, preferably of at least 120°C, more preferably of at least 140°C.

3. The composition according to claim 1 or 2, characterized in that, in formula (la), Ri represents an aliphatic saturated branched C4-C9 alkyl group and R2 represents an alkoxy group -OR’2 wherein R’2 represents a saturated branched C3-C9 alkyl group.

4. The composition according to any of the preceding claims, characterized in that said at least one organic peroxide of formula (la) and / or (lb) is chosen among the group consisting of tert-butylperoxy 2-ethylhexyl carbonate, OO-tert-amyl-O-2 -ethylhexyl monoperoxycarbonate, tert-butylisopropyl monoperoxycarbonate, tert-amyisopropyl monoperoxycarbonate, polyether poly-tert-butylperoxycarbonate, tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy isobutyrate, tert-butyl peroxy-3, 5, 5 -trimethylhexanoate, tert-amyl peroxy-3,5,5-trimethylhexanoate, di-2-ethylhexylpercarbonate, and mixtures thereof, preferably chosen among the group consisting of tert-butylperoxy 2-ethylhexyl carbonate, OO-tert-amyl-O-2-ethylhexyl monoperoxy carbonate, tert-butylisopropyl monoperoxy carbonate, tert-amy isopropyl monoperoxy carbonate, polyether poly-tert-butylperoxycarbonate and mixtures thereof preferably chosen among the group consisting of tert-butylperoxy 2-ethylhexyl carbonate, OO-tert-amyl-O-2 -ethylhexyl monoperoxycarbonate, tert-butylisopropyl monoperoxycarbonate, tert-amyisopropyl monoperoxycarbonate, and mixtures thereof, and most preferably among the group consisting of tert-butylperoxy 2-ethylhexyl carbonate, OO-tert-amyl-O-2 -ethylhexyl monoperoxycarbonate and mixtures thereof.

5. The composition according to any of the preceding claims, characterized in that, in formula (Il-b), R’30 and R’40, identical or different, preferably identical, represent an aliphatic saturated linear or branched alkyl group, preferably a linear alkyl group, comprising less than 4 carbon atoms or 4 carbon atoms.

6. The composition according to any of the preceding claims, characterized in that, in formula (Il-b), R’30 and R’40 are identical and represent an aliphatic saturated linear or branched, preferably linear, alkyl group comprising less than 4 carbon atoms or 4 carbon atoms.

7. The composition according to any of the preceding claims, characterized in that, in formula (Il-a), R3 and R4 form together a ring of at most three carbon atoms which may be substituted with one or more halogen atoms chosen from the group consisting of fluorine atom, bromine atoms, one or more C1-C4 alkyl groups, preferably one or more C1-C2 alkyl groups, and mixture thereof.

8. The composition according to any of the preceding claims, characterized in that said at least one compound of formula (Il-a) or (Il-b) has a boiling point higher than 50°C, preferably higher than or equal to 70°C, more preferably higher than or equal to 100°C, even better higher than or equal to 140°C.

9. The composition according to any of the preceding claims, characterized in that said at least one compound of formula (Il-a) or (Il-b) is chosen among the group consisting of methyl acetate, ethyl acetate, methyl propionate, dimethyl carbonate, ethyl propionate, propyl acetate, ethyl methyl carbonate, diethyl carbonate, trimethylene carbonate, dipropyl carbonate, fluoroethylene carbonate, dibutyl carbonate, bromoethylene carbonate, propylene carbonate, chloroethylene carbonate, butylene carbonate, ethylene carbonate, propyl phenyl acetate, diphenyl carbonate, ethyl acetate, dimethyl carbonate and mixture thereof, preferably chosen from the group consisting of ethyl methyl carbonate, diethyl carbonate, trimethylene carbonate, dipropyl carbonate, fluoroethylene carbonate, dibutyl carbonate, bromoethylene carbonate, propylene carbonate, butylene carbonate, ethylene carbonate, diphenyl carbonate, and mixture thereof and even more preferably among the group consisting of ethylene carbonate, dimethyl carbonate, ethyl acetate, propylene carbonate and mixtures thereof, and even more preferably is ethylene carbonate.

10. The composition according to any of the preceding claims, comprising at least two organic peroxide of formula (I-a) or (I-b), different from each other, preferably said the second organic peroxide corresponding to formula (III):[Chem 2]OR5_ O— O -U— R6(HI)Formula (III) whereinRs represents an aliphatic saturated linear or branched C3-C9 alkyl group or an aromatic group having from 3 to 9 carbon atoms,Re represents an aliphatic saturated linear or branched C3-C10 alkyl group, said at least one organic peroxide of formula (III) being different from said at least one organic peroxide of formula (I-a) and / or (I-b) , preferably said at least one organic peroxide of formula (III) is chosen among the group consisting of tert-butyl-peroxy-2-ehtylhexanoate, tert-amyl-peroxy-2-ehtylhexanoate, tertbutyl peroxybenzoate, tert-amyl peroxybenzoate, tert-butyl peroxy-3.5.5- trimethylhexanoate, tert-amyl peroxy-3.5.5 -trimethylhexanoate, tert-butyl peroxy-3.5.5 -trimethylhexanoate, tert-butyl peroxyisobutyrate, and mixtures thereof.

11. The composition according to any of the preceding claims, characterized in that the weight ratio of said at least one organic peroxide of formula (I-a) and / or (I-b) to said at least one compound of formula (II), ranges from 0.005 to 50, preferably from 0.01 to 30, and even preferably from 0.1 to 20.

12. Use of a composition comprising:at least one organic peroxide selected in the group consisting of:o formula (I-a):RI-O-O-C(=O)-R2(I-a)Formula (I-a) wherein:Ri represents an alkyl group R’ 1 or an ester group -C(=O)O-R’ 1, wherein R’ 1 is a saturated linear or branched C3-C9 alkyl group or an aromatic group having from 3 to 9 carbon atoms,R2 represents an alkyl group R’2 or an alkoxy group -OR’ 2 wherein R’2 represents a saturated linear or branched C3-C30 alkyl group, preferably a C3-C10 alkyl group;o formula (I-b):C-[{CR}y-[-O-R7-]x-O-C(O)-O-O-R8]4(I-b)Formula (I-b) wherein:- R is an aliphatic saturated alkyl group comprising less than or 8 carbon atoms;- R7 represents a C2-C10 alkene group- R8is selected in the group consisting of: C1-C10 alkyl group, C3-C10 cycloalkyl group and Ce-Cis aryl group,- x et y independently represent an integer from 1 to 10;o and mixtures thereof,preferably the at least one organic peroxide is of formula (la) as defined above,at least one compound selected in the group consisting of:o formula (Il-a):[Chem 1]R3-O-C-(O)R4(Il-a) Formula (Il-a) wherein:R3 and R4 may form together a ring of at most three carbon atoms which may substituted with one or more halogen atoms and / or one or more C1-C4 alkyl groups;o formula (Il-b)R3O-0-(C=0) -R4O (Il-b)Formula (Il-b) wherein:R30 represents an alkyl group R’30 ,R40 represents an alkyl group R’40 or an alkoxy group -OR’ 40, wherein R’30 and R’40, identical or different, represent:- an aliphatic saturated linear or branched alkyl group comprising less than or 8 carbon atoms, which may be substituted by at least one aromatic group having from 5 to 8 carbon atoms, preferably by at least one benzene ring, or- an aromatic group having from 3 to 9 carbon atoms;and mixtures thereof,for crosslinking at least one crosslinkable polymer, preferably chosen among the group consisting of low-density polyethylene, high-density polyethylene, polyvinyl butyral, ethylene-propylene-diene terpolymers, ethylene-vinyl acetate copolymers, ethylenepropylene copolymers, ethyl ene-butene copolymers, in particular ethylene- 1- butene copolymers, ethyl ene-octene copolymers, in particular ethylene- 1 -octene copolymers, silicone rubber, natural rubber, polyisoprene, polybutadiene (BR), acrylonitrile-butadiene copolymers, styrene-butadiene copolymers, chlorosulfonated polyethylene or fluoroelastomers, ethylene-methyl (meth)acrylate copolymers, ethylene-glycidyl methacrylate copolymers, styrene-butadiene-styrene block copolymer, and mixtures thereof.

13. Use of at least one composition as defined in any of claims 1 to 12, for polymerizing and / or curing systems containing at least one unsaturated monomer,preferably chosen from the group consisting of vinyl monomers and / or acrylate monomers.

14. Crosslinkable composition comprising at least one crosslinkable polymer, as defined in claim 12, and at least one composition as defined in any of claims 1 to 13.

15. The composition according to claim 15, wherein the total content of organic peroxides ranges from 0.1 to 20% by weight, preferably from 0.1 to 10% by weight, more preferably from 0.1 to 5 more preferably in a content ranging from 0.1 to 3% by weight, relative to the total weight of said crosslinkable composition.

16. Use of at least one crosslinkable composition as defined in claim 14 or 15 for producing at least one system capable of producing energy based on solar energy, preferably at least one photovoltaic module, especially in the encapsulation process of solar cells in a photovoltaic module.

17. Polymerizable composition comprising at least one unsaturated monomer, as defined in claim 14, and at least one composition as defined in any of claims 1 to 12.

Images