Peroxide formulations with anti-scorch properties

Abstract

The present invention relates to an organic peroxide formulation comprising:-at least one organic peroxide having a one-hour half-life temperature of from 90 DEG C to 130 DEG C, and-at least one drying oil wherein the weight ratio of drying oil to organic peroxide is less than or equal to 0.60. The invention also relates to a composition comprising at least one polymer and such an organic peroxide formulation, a method for preparing the same and a method for manufacturing an article using such a composition.

Description

Technical Field

[0001] The present invention relates to an organic peroxide formulation comprising a drying oil and a polymer composition comprising such an organic peroxide formulation, which can be used in particular for the manufacture of photovoltaic modules. The present invention is also applicable to articles obtainable by curing said polymer composition. Background Art

[0002] Solar modules (also known as photovoltaic modules) are gaining more and more interest due to their renewable and pollution-free nature in generating energy. Solar modules contain photovoltaic cells composed of photovoltaic components that generate a voltage when exposed to light.

[0003] Conventionally, in solar modules, photovoltaic cells are placed between an upper (or front) protective layer, also called a front sheet, typically a glass or plastic plate, and a rear protective panel, often made of plastic or glass, usually called a back sheet. Classically, photovoltaic cells are encapsulated by a polymeric material, called an encapsulant, applied as a film to either the front or both sides of the photovoltaic cells in order to assemble and bond the photovoltaic cells and the protective layer, such as the upper protective layer, usually made of glass, together to provide electrical insulation and protect the photovoltaic cells from the elements of the outdoor environment, especially moisture and UV radiation.

[0004] As encapsulants, materials based on ethylene polymers are generally used. In particular, ethylene-vinyl acetate (EVA) copolymers are widely used because they can produce transparent materials that can be easily adhered to the substrate of the photovoltaic module while having a high resistivity. Other polymers that can be used to produce encapsulant materials include polyolefin elastomers (POE).

[0005] In order to obtain the thermomechanical properties required for such applications, in particular with regard to adhesion properties, creep resistance and resistance to degradation with respect to weather adversities, the polymer of the encapsulant must be crosslinked.

[0006] Photovoltaic modules are generally produced by a lamination process. There are several module technologies. In conventional modules, the encapsulant layer is located between the photovoltaic unit cell and the front glass protective layer, and the rear protective plate is made of other types of protective films. In the so-called "double glass technology", a transparent EVA or POE layer forms the top encapsulation layer (between the front glass protective layer and the unit cell), and a white film (often also made of EVA or POE) is located between the back of the unit cell and the rear glass protective plate. The laminated layers forming the module are then pressed, and the encapsulant layer is crosslinked (or cured) by heating at the same time as the pressing step or subsequently. The encapsulant layer is generally produced by an extrusion step.

[0007] If premature decomposition of the organic peroxide occurs during the extrusion step, the polymer composition used to form the encapsulant layer is susceptible to premature crosslinking over time in the barrel or head of the extruder in which it is processed, before the formation of the laminated structure. This phenomenon, which is called "scorching", leads to irregularities (unevenness, surface roughness) in the polymer sheet thus formed and intended to encapsulate the photovoltaic unit cells. The presence of these irregularities impairs the appearance and properties of the photovoltaic module. In addition, in some cases, pressure can also accumulate in the extruder, which requires interruption of the extrusion process and, as a result, production efficiency slows down.

[0008] Therefore, some peroxide formulations have been developed with anti-scorch properties.

[0009] For example, document WO 2019 / 115975 relates to the use of a combination of two different monoperoxycarbonates for crosslinking polyolefin elastomers.

[0010] Documents WO 2016 / 149898 and WO 2018 / 046700 describe curable compositions comprising ethylene polymers, monoperoxycarbonates and tertiary alkyl hydroperoxides in specific amounts.

[0011] In addition to scorch protection, it is also desirable to achieve a high crosslink density. Indeed, if the crosslink density is too low, the resulting material may suffer from, among other things, insufficient tear and break resistance and may flow over time due to the high temperatures reachable by the upper surface of the photovoltaic module. However, the anti-scorch compositions disclosed in the prior art do not always allow excellent crosslink densities to be achieved. It is also preferred that once the laminate structure is formed and heated above the peroxide decomposition temperature, crosslinking proceeds rapidly to improve production efficiency.

[0012] Therefore, there is a need for an organic peroxide formulation that allows for reduced scorch while providing good crosslink density and rapid crosslinking. Summary of the invention

[0013] The first object of the present invention is to provide an organic peroxide formulation comprising:

[0014] - at least one organic peroxide having a one-hour half-life temperature of from 90°C to 130°C, preferably having a one-hour half-life of from 110°C to 125°C, and

[0015] - at least one drying oil,

[0016] The weight ratio of the drying oil to the organic peroxide is less than or equal to 0.60.

[0017] In some embodiments, the at least one drying oil has an iodine value of from 125 to 215 g / 100 g, preferably from 140 to 205 g / 100 g, more preferably from 150 to 180 g / 100 g.

[0018] In some embodiments, the at least one drying oil has a saponification value of from 175 to 200 mg KOH / g, preferably from 180 to 195 mg KOH / g.

[0019] In some embodiments, at least one drying oil is selected from tung oil, hemp oil, linseed oil, poppy seed oil, walnut oil, sunflower oil, cottonseed oil, corn oil, soybean oil, fish oil such as sardine oil and cod liver oil, herring oil, safflower oil, flax seed oil, perilla oil, oiticica oil and combinations thereof, preferably at least one drying oil is tung oil.

[0020] In some embodiments, the at least one organic peroxide is selected from diperoxyketals, peroxyketals, monoperoxycarbonates, cyclic ketone peroxides, diacyl peroxides, organic sulfonyl peroxides, peroxyesters, peroxydicarbonates and combinations thereof, preferably selected from diperoxyketals, peroxyketals, monoperoxycarbonates, peroxyesters and combinations thereof, more preferably selected from OO-tert-butyl-O-(2-ethylhexyl)-monoperoxycarbonate, OO-tert-butyl-O-2-isopropyl-monoperoxycarbonate, OO-tert-amyl-O-(2-ethylhexyl)-monoperoxycarbonate, OO-tert-amyl-O-2-isopropyl-monoperoxycarbonate, OO-tert-hexyl-O-(2-ethylhexyl)-monoperoxycarbonate and mixtures thereof, optionally in combination with at least one other peroxide.

[0021] In some embodiments, the organic peroxide formulation comprises a combination of at least:

[0022] 1) a monoperoxycarbonate, preferably selected from OO-tert-butyl-O-(2-ethylhexyl)-monoperoxycarbonate, OO-tert-butyl-O-2-isopropyl-monoperoxycarbonate, OO-tert-amyl-O-(2-ethylhexyl)-monoperoxycarbonate, OO-tert-amyl-O-2-isopropyl-monoperoxycarbonate, OO-tert-hexyl-O-(2-ethylhexyl)-monoperoxycarbonate and mixtures thereof, and

[0023] 2) a peroxyester, preferably selected from: tert-butyl peroxy-2-ethylhexanoate and tert-amyl peroxy-2-ethylhexanoate,

[0024] More preferred is a combination of 0-tert-amyl-0-(2-ethylhexyl)-monoperoxycarbonate and tert-butylperoxy-2-ethylhexanoate.

[0025] In some embodiments, the organic peroxide formulation further comprises at least one silane component, which is preferably selected from vinyl triethoxysilane, vinyl tris (2-methoxyethoxy) silane, 3-methacryloxypropyl triethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-glycidoxypropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyl trimethoxysilane, N-2- (aminoethyl) -3-aminopropyl triethoxysilane, 3-mercaptopropyl trimethoxysilane and mixtures thereof, and more preferably 3-methacryloxypropyl triethoxysilane or / and 3-methacryloxypropyl trimethoxysilane.

[0026] In some embodiments, the weight ratio of drying oil to organic peroxide is less than or equal to 0.45, preferably from 0.025 to 0.45, more preferably from 0.03 to 0.3, more preferably from 0.03 to 0.25, and even more preferably from 0.05 to 0.2.

[0027] In some embodiments, the organic peroxide formulation further comprises at least one auxiliary agent, preferably selected from triallyl cyanurate, triallyl isocyanurate, N,N'-m-phenylenedimaleimide, triallyl trimellitate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trivinylcyclohexane, and mixtures thereof.

[0028] The invention also relates to a composition comprising at least one polymer and an organic peroxide formulation as described above.

[0029] In some embodiments, at least one polymer is an ethylene polymer, particularly poly(ethylene vinyl acetate) and / or a polyolefin elastomer.

[0030] In some embodiments, the amount of the at least one drying oil in the composition is from 0.005 to 10 parts by weight, preferably from 0.01 to 5 parts by weight, more preferably from 0.02 to 1 part by weight, based on 100 parts by weight of the at least one polymer.

[0031] The present invention also relates to a process for preparing an organic peroxide formulation as described above, comprising mixing at least one organic peroxide and at least one drying oil.

[0032] The present invention also relates to a method for manufacturing an article, comprising the step of curing the composition as described above.

[0033] The invention also relates to an article, in particular a film, obtainable by a process as described above.

[0034] The present invention also relates to the use of an organic peroxide formulation as described above for curing a polymer, preferably selected from the group consisting of polyethylene vinyl acetate, polyolefin elastomers and combinations thereof.

[0035] The present invention makes it possible to meet the above needs. In particular, the present invention provides organic peroxide formulations which make it possible to increase the scorch time and thereby minimize the risk of premature crosslinking, and to increase the crosslink density and the crosslinking rate.

[0036] This is achieved by the presence of the drying oil in the peroxide formulation at a specific weight ratio relative to the organic peroxide. DETAILED DESCRIPTION

[0037] In the following description, the invention will now be described in more detail but without limitation.

[0038] Unless otherwise stated, all percentages herein are by weight.

[0039]

[0066] Herein, the amounts noted for a given substance may apply to that substance according to all of its definitions (as described herein), including more narrow definitions.

[0040] Organic peroxide formulations

[0041] The organic peroxide formulation of the present invention comprises at least one organic peroxide having a one hour half life temperature (HLT) of from 90°C to 130°C.

[0042] The organic peroxide may be any organic peroxide having the one hour HLT described above.

[0043] Preferably, the organic peroxide has a one hour half life temperature of from 95°C to 125°C, more preferably from 110°C to 125°C, even more preferably from 115 to 125°C.

[0044] The term "one-hour half-life temperature" represents the temperature at which half of the organic peroxide decomposes within a given time of one hour. Conventionally, the "one-hour half-life temperature" is measured in n-decane or n-dodecane.

[0045] For example, the organic peroxide can be selected from diperoxyketals, peroxyketals, monoperoxycarbonates, cyclic ketone peroxides, diacyl peroxides, organic sulfonyl peroxides, peroxyesters, peroxydicarbonates and combinations thereof. More particularly, the organic peroxide can be selected from diperoxyketals, peroxyketals, monoperoxycarbonates, peroxyesters and combinations thereof.

[0046] For purposes of the present invention, "diperoxyketal" includes peroxides containing two peroxide groups (OO) on at least one of the same carbons.

[0047] Examples of suitable diperoxyketals for use in the present invention are 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane; 1,1-di(tert-butylperoxy)cyclohexane; n-butyl 4,4-di(tert-amylperoxy)valerate; ethyl 3,3-di(tert-butylperoxy)butyrate; 2,2-di(tert-amylperoxy)propane; 3,6,6,9,9-pentamethyl-3-ethoxycarbonylmethyl-1,2,4,5-tetraoxacyclononane; n-butyl-4,4-di(tert-butylperoxy)valerate; ethyl-3,3-di(tert-amylperoxy)butyrate; and mixtures thereof.

[0048] The term "peroxyketal" refers to a compound of the general formula (R 3 )(R 4 )C(-OR 1 )(-OOR 2 ), wherein:

[0049] -R 1 represents a straight chain or a branched chain, preferably C 1 -C 12 , preferably C 1 -C 4 , and more preferably C 1 Alkyl group, or represents 2 A cycloalkyl group,

[0050] -R 2 represents a straight chain or a branched chain, preferably C 1 -C 12 , preferably C 4 -C 12 , and more preferably C 5 Alkyl group, or represents 1 A cycloalkyl group,

[0051] -R 3 represents a hydrogen atom or a straight or branched chain, preferably C 1 -C 12 , more preferably C 4 -C 12 Alkyl group, or represents 4 A cycloalkyl group,

[0052] -R 4 represents a hydrogen atom or a straight or branched chain, preferably C 1 -C 12 , more preferably C4 -C 12 Alkyl group, or represents 3 A cycloalkyl group.

[0053] Preferably, R 3 With R 4 A cycloalkyl group is formed.

[0054] Preferably, when R 3 When it is a hydrogen atom, R 4 It is a straight chain or branched chain, preferably C 1 -C 12 , more preferably C 4 -C 12 Alkyl group.

[0055] The peroxyketals according to the invention preferably have the following general formula (I):

[0056]

[0057] Wherein formula (I):

[0058] -R 1 Represents a straight or branched chain C 1 -C 4 , preferably C 1 Alkyl groups,

[0059] -R 2 Represents branched chain C 4 -C 12 , preferably C 5 Alkyl groups,

[0060] -n represents zero or an integer from 1 to 3,

[0061] -R 3 Represents a straight or branched chain C 1 -C 3 Alkyl group.

[0062] R 1 Preferably represents a straight chain, more particularly C 1 -C 2 , more preferably C 1 Alkyl group.

[0063] R 2 Preferably represents branched C 4 -C 5 , more preferably C 5 Alkyl group.

[0064] n preferably represents zero.

[0065] R 3 Preferably represents a straight or branched C 1 -C2 , more preferably C 1 Alkyl group.

[0066] Preferably, in formula (I), R 1 Represents a straight chain or a branched chain, C 1 -C 2 Alkyl group, R 2 Represents branched chain C 4 -C 5 An alkyl group, and n represents zero.

[0067] Still more preferably, in formula (I), R 1 Represents C 1 Alkyl group, R 2 Represents branched chain C 5 An alkyl group and n represents zero.

[0068] The organic peroxide(s) are preferably selected from 1-methoxy-1-tert-amylperoxycyclohexane (TAPMC), 1-methoxy-1-tert-butylperoxycyclohexane (TBPMC), 1-methoxy-1-tert-amylperoxy-3,3,5-trimethylcyclohexane, 1-methoxy-1-tert-butylperoxy-3,3,5-trimethylcyclohexane, 1-ethoxy-1-tert-amylperoxycyclohexane, 1-ethoxy-1-tert-butylperoxycyclohexane, 1-ethoxy-1-tert-butyl-3,3,5-peroxycyclohexane and mixtures thereof.

[0069] Still more preferably, the organic peroxide according to the present invention is 1-methoxy-1-tert-amylperoxycyclohexane (TAPMC).

[0070] As peroxyesters that can be used in the present invention, mention may be made of 2,5-dimethyl-2,5-di(benzoylperoxy)hexane; tert-butyl perbenzoate; tert-butyl peroxyacetate; tert-butyl peroxy-2-ethylhexanoate; tert-amyl perbenzoate; tert-amyl peroxyacetate; tert-butyl peroxyisobutyrate; 3-hydroxy-1,1-dimethyl tert-butyl peroxy-2-ethylhexanoate; OO-tert-amyl-O-hydrogen-monoperoxysuccinate; OO-tert-butyl-O-hydrogen-monoperoxybutyrate. di-tert-butyl diperoxyphthalate; tert-butyl peroxy (3,3,5-trimethylhexanoate); 1,4-bis (tert-butylperoxycarbo) cyclohexane; tert-butyl peroxy-3,5,5-trimethylhexanoate; tert-butyl-peroxy-(cis-3-carboxy) propionate; allyl 3-methyl-3-tert-butyl peroxybutyrate; and mixtures thereof.

[0071] The monoperoxycarbonates suitable for use in the present invention are OO-tert-butyl-O-2-isopropyl-monoperoxycarbonate; OO-tert-amyl-O-2-isopropyl-monoperoxycarbonate, OO-tert-hexyl-O-isopropyl-monoperoxycarbonate, OO-tert-butyl-O-(2-ethylhexyl)-monoperoxycarbonate; OO-tert-amyl-O-(2-ethylhexyl)-monoperoxycarbonate, OO-tert-hexyl-O-(2-ethylhexyl)-monoperoxycarbonate, 1,1,1- tris[2-(tert-butylperoxy-carbonyloxy)ethoxymethyl]propane; 1,1,1-tris[2-(tert-amylperoxy-carbonyloxy)ethoxymethyl]propane; 1,1,1-tris[2-(isopropylphenylperoxy-carbonyloxy)ethoxymethyl]propane; OO-tert-amyl-O-n-propyl monoperoxycarbonate; OO-tert-octyl-O-isopropyl-monoperoxycarbonate; OO-tert-octyl-O-(2-ethylhexyl)-monoperoxycarbonate; and mixtures thereof.

[0072] Suitable diacyl peroxides for use in the present invention include di(4-methylbenzoyl) peroxide; di(3-methylbenzoyl) peroxide; di(2-methylbenzoyl) peroxide; didecanoyl peroxide; dilauroyl peroxide; 2,4-dibromobenzoyl peroxide; succinic acid peroxide; dibenzoyl peroxide; di(2,4-dichlorobenzoyl) peroxide; and mixtures thereof.

[0073] Imido peroxides, such as the type described in PCT publication WO 97 / 03961, may also be used.

[0074] Preferably, the organic peroxide comprises or consists of at least one monoperoxycarbonate. More preferably, the peroxide comprises or consists of at least one OO-tert-alkyl-O-alkyl monoperoxycarbonate.

[0075] Advantageously, the organic peroxide is selected from OO-tert-amyl-O-2-isopropyl-monoperoxycarbonate (TAIC), OO-tert-amyl-O-n-propyl-monoperoxycarbonate (TAPC), OO-tert-butyl-O-2-isopropyl-monoperoxycarbonate (TBIC), tert-octyl-isopropyl-monoperoxycarbonate (TOIC), OO-tert-hexyl-O-isopropyl-monoperoxycarbonate (THIC), OO-tert-amyl-O-(2-ethylhexyl)-monoperoxycarbonate (TAEC), OO-tert-butyl-O-(2-ethylhexyl)-monoperoxycarbonate (TBEC), OO-tert-octyl-O-(2-ethylhexyl)-monoperoxycarbonate (TOEC), OO-tert-hexyl-O-(2-ethylhexyl)-monoperoxycarbonate (THEC) and mixtures thereof. More preferably, the organic peroxide is selected from OO-tert-butyl-O-(2-ethylhexyl)-monoperoxycarbonate (TBEC), OO-tert-butyl-O-2-isopropyl-monoperoxycarbonate (TBIC), OO-tert-amyl-O-(2-ethylhexyl)-monoperoxycarbonate (TAEC), OO-tert-amyl-O-2-isopropyl-monoperoxycarbonate (TAIC), OO-tert-hexyl-O-(2-ethylhexyl)-monoperoxycarbonate (THEC) and mixtures thereof. These monoperoxycarbonates may optionally be used in combination with at least one additional peroxide, such as those mentioned above (e.g. tert-butyl peroxy-2-ethylhexanoate).

[0076] Even more preferred organic peroxides are TBEC, TAEC, THEC or mixtures thereof, optionally used in combination with at least one additional peroxide, such as those mentioned above (e.g. tert-butyl peroxy-2-ethylhexanoate). The most preferred organic peroxides are TBEC, TAEC or mixtures thereof, optionally used in combination with at least one additional peroxide, such as those mentioned above (e.g. tert-butyl peroxy-2-ethylhexanoate).

[0077] Advantageously, the organic peroxide formulation of the present invention comprises at least the following combination:

[0078] 1) a monoperoxycarbonate, preferably selected from OO-tert-butyl-O-(2-ethylhexyl)-monoperoxycarbonate, OO-tert-butyl-O-2-isopropyl-monoperoxycarbonate, OO-tert-amyl-O-(2-ethylhexyl)-monoperoxycarbonate, OO-tert-amyl-O-2-isopropyl-monoperoxycarbonate, OO-tert-hexyl-O-(2-ethylhexyl)-monoperoxycarbonate and mixtures thereof, and

[0079] 2) a peroxyester, preferably selected from tert-butyl peroxy-2-ethylhexanoate and tert-amyl peroxy-2-ethylhexanoate,

[0080] More preferred is a combination of at least 0-tert-amyl-0-(2-ethylhexyl)-monoperoxycarbonate and tert-butylperoxy-2-ethylhexanoate.

[0081] Preferably, when a combination of at least one monoperoxycarbonate and one peroxyester is used, it comprises from 70 to 97% by weight of monoperoxycarbonate and from 3 to 30% by weight of peroxyester relative to the total weight of the combination.

[0082] The organic peroxide present in the formulation may consist of organic peroxides as defined above including combinations of organic peroxides.

[0083] The organic peroxide may be present in the formulation in an amount of from 40 to 99 wt %, based on the total weight of the organic peroxide formulation. Preferably, the organic peroxide is present in the formulation in an amount of from 50 to 98 wt %, even more preferably from 60 to 97 wt %, based on the total weight of the organic peroxide formulation.

[0084] The organic peroxide formulation of the present invention also comprises at least one drying oil. The so-called "drying oil" refers to an oil having an iodine value higher than 110 g / 100 g as determined according to standard GB / T5532-2008. Any drying oil known to those skilled in the art may be used in the organic peroxide formulation of the present invention. The drying oil may include oils derived from plants, animals and fish sources, for example, triglycerides including fatty acids characterized by relatively high levels of polyunsaturated fatty acids, especially eleostearic acid and alpha-linolenic acid. Advantageously, at least one drying oil is selected from tung oil, hemp oil, biofene or trans-beta-farnesene (e.g. produced by Amyris), linseed oil, poppy seed oil, walnut oil, sunflower oil, cottonseed oil, corn oil, soybean oil, fish oils such as sardine oil and cod liver oil, herring oil, safflower oil, flax seed oil, perilla oil, oatmeal oil and combinations thereof, preferably selected from tung oil, hemp oil, linseed oil, poppy seed oil, walnut oil, sunflower oil, cottonseed oil, corn oil, soybean oil, fish oils such as sardine oil and cod liver oil, herring oil, safflower oil, linseed oil, perilla oil, oatmeal oil and combinations thereof.

[0085] More preferably, the drying oil comprises, consists essentially of, or consists of: tung oil, linseed oil, fish oil, in particular cod liver oil, walnut oil, oatmeal oil, poppy seed oil. Most preferably, the drying oil comprises, consists essentially of, or consists of: tung oil or linseed oil, and in particular tung oil.

[0086] The above oil may be modified or not. It may be virgin oil or refined oil.

[0087] The drying oil used in the formulation of the present invention preferably has an iodine value of from 125 to 215 g / 100 g, preferably from 140 to 205 g / 100 g, more preferably from 150 to 180 g / 100 g. The iodine value can be determined according to standard GB / T5532-2008.

[0088] The drying oil may have a saponification value of from 175 to 210 mg KOH / g, preferably from 182 to 195 mg KOH / g.

[0089] The peroxide formulation advantageously contains the drying oil in an amount of from 1 to 35 wt %, based on the total weight of the organic peroxide formulation. More preferably, the organic peroxide formulation of the present invention contains the drying oil in an amount of from 2 to 25 wt %, more preferably 3 to 20 wt %, even more preferably 5 to 15 wt %, based on the total weight of the organic peroxide formulation.

[0090] The weight ratio of drying oil to organic peroxide in the organic peroxide formulation is lower than or equal to 0.60, preferably lower than 0.45. More preferably, the weight ratio of drying oil to organic peroxide is from 0.025 to 0.45, preferably from 0.03 to 0.3, more preferably from 0.03 to 0.025, even more preferably from 0.05 to 0.2, even more preferably from 0.1 to 0.2.

[0091] When two or more organic peroxides are present in the organic peroxide formulation, the weight ratio of the drying oil to the organic peroxide is based on the total weight of the organic peroxides.

[0092] When two or more drying oils are present in the organic peroxide formulation, the weight ratio of the drying oil to the organic peroxide is based on the total weight of the drying oils.

[0093] The organic peroxide formulation may also include a silane component. The silane component has a scorch protection effect and makes it possible to further increase the scorch time. The silane component may further act as a coupling agent, which makes it possible to improve the adhesion properties of the polymer composition using the peroxide formulation.

[0094] In some embodiments, the silane component may be a silane component having an amino functional group, a silane component having a sulfur functional group, a silane component having an epoxy functional group, a silane component having a (meth)acryloyl functional group, a silane component having a chlorine functional group, and / or a silane component having a vinyl (vinyl) functional group.

[0095] The silane component can be selected from 3-aminopropyl triethoxysilane; 3-aminopropyl trimethoxysilane; aminopropyl methyl dimethoxysilane; N-2-(aminoethyl)-3-aminopropyl trimethoxysilane; N-2-(aminoethyl)-3-aminopropyl triethoxysilane; N-2-(aminoethyl)-3-aminopropyl methyl dimethoxysilane; diethylene triaminopropyl trimethoxysilane; diethylene triaminopropyl triethoxysilane; diethylene triaminopropyl trimethoxysilane; Triaminopropylmethyldimethoxysilane; Diethylenetriaminopropylmethyldiethoxysilane; 3-cyclohexylaminopropyltrimethoxysilane; Hexanediaminomethyldiethoxysilane; Anilinomethyltrimethoxysilane; Anilinomethyltriethoxysilane; Diethylaminomethyltriethoxysilane; (Diethylaminoethyl)methyldiethoxysilane; N-methylaminopropyltrimethoxysilane; Bis(triethoxysilylpropyl)tetrasulfide; Bis(triethoxysilylpropyl)tetrathiophene 3-Mercaptopropyltrimethoxysilane; 3-Mercaptopropyltriethoxysilane; 3-Mercaptopropylmethyldimethoxysilane; 3-Thiocyanatopropyltriethoxysilane; 3-Glycidyloxypropyltrimethoxysilane; 3-Glycidyloxypropyltriethoxysilane; 3-Glycidyloxypropylmethyldiethoxysilane; 3-Glycidyloxypropylmethyldimethoxysilane; 3-Methacryloxypropyltrimethoxysilane; 3-methacryloxypropyltriethoxysilane; 3-methacryloxypropylmethyldimethoxysilane; 3-chloropropyltrimethoxysilane; 3-chloropropyltriethoxysilane; chloromethyltriethoxysilane; chloromethyltrimethoxysilane; dichloromethyltrimethoxysilane; vinyltrimethoxysilane; vinyltriethoxysilane; vinyltri(2-methoxyethoxy)silane; and mixtures thereof.

[0096] The silane component is preferably selected from vinyl triethoxysilane, vinyl tris (2-methoxyethoxy) silane, 3-methacryloxypropyl triethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-glycidoxypropyl trimethoxysilane, N-2- (aminoethyl) -3-aminopropyl trimethoxysilane, N-2- (aminoethyl) -3-aminopropyl triethoxysilane, 3-mercaptopropyl trimethoxysilane and mixtures thereof. More preferably, the silane component comprises 3-methacryloxypropyl triethoxysilane or / and 3-methacryloxypropyl trimethoxysilane, or consists of 3-methacryloxypropyl triethoxysilane or / and 3-methacryloxypropyl trimethoxysilane, and even more preferably, the silane component is 3-methacryloxypropyl trimethoxysilane.

[0097] The amount of the silane component in the organic peroxide formulation is advantageously from 5 to 50 wt%, preferably from 10 to 50 wt%, more preferably from 20 to 40 wt%, based on the total weight of the organic peroxide formulation.

[0098] The weight ratio of the silane component to the organic peroxide is preferably from 0.1 to 1, more preferably from 0.3 to 0.7.

[0099] When two or more organic peroxides are present in the organic peroxide formulation, the weight ratio of the silane component to the organic peroxide is based on the total weight of the organic peroxides.

[0100] When two or more silane components are present in the organic peroxide formulation, the weight ratio of the silane component to the organic peroxide is based on the total weight of the silane components.

[0101] The organic peroxide formulation may consist essentially of, or consist of, at least at least one organic peroxide and at least one drying oil.

[0102] Alternatively, the organic peroxide formulation may consist essentially of, or consist of, at least one organic peroxide, at least one drying oil, and at least one silane component.

[0103] Alternatively, the organic peroxide formulation may further comprise an auxiliary agent (which is not an organic peroxide). Advantageously, the auxiliary agent carries at least one carbamate, maleimide, acrylate, methacrylate or allyl functional group. Allyl carboxylates may be used, which may be selected from allyl, diallyl and triallyl types.

[0104] The auxiliary agent can be selected from divinylbenzene, diisopropenylbenzene, α-methylstyrene, α-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, 1,3-glycerol dimethacrylate, diurethane 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, trihydroxymethyl triacrylate, trimethylolpropane ethoxylate triacrylate, trimethylolpropane propoxylate triacrylate, glycerol propoxylate triacrylate, aliphatic urethane triacrylate, dipentaerythritol pentaacrylate, triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), triallyl trimellitate, N,N'-m-phenylenedimaleimide, butadiene, chloroprene, isoprene, trivinylcyclohexane and mixtures thereof.

[0105] More preferably, the auxiliary agent is selected from triallyl cyanurate, triallyl isocyanurate, N,N'-m-phenylenedimaleimide, triallyl trimellitate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trivinylcyclohexane and mixtures thereof, even more preferably selected from triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA) and mixtures thereof, and most preferably triallyl isocyanurate (TAIC).

[0106] The main purpose of using an auxiliary is to increase the level of crosslinking of the polymer cured using the formulation of the invention. The auxiliary also makes it possible to reduce the residual gas emissions during the decomposition of the peroxide and ultimately reduce the number of bubbles in the encapsulating film.

[0107] The weight ratio of the auxiliary agent to the organic peroxide is preferably from 0.1 to 10, more preferably from 0.3 to 3, even more preferably from 0.4 to 1.

[0108] When two or more organic peroxides are present in the organic peroxide formulation, the weight ratio of the adjuvant to the organic peroxide is based on the total weight of the organic peroxides.

[0109] When two or more adjuvants are present in the organic peroxide formulation, the weight ratio of the adjuvants to the organic peroxide is based on the total weight of the adjuvants.

[0110] In some embodiments, the organic peroxide formulation may consist essentially of, or consist of, at least one organic peroxide, at least one drying oil, at least one silane component, and at least one adjuvant.

[0111] In other embodiments, the organic peroxide formulation may include one or more other additives, preferably selected from UV stabilizers, UV absorbers, coupling agents, fillers, plasticizers, flame retardants, antioxidants, dyes and pigments, free radical scavengers and mixtures thereof. UV stabilizers may be selected from hindered amine light stabilizers (HALS). UV absorbers may be selected from, for example, benzophenones, triazines and benzotriazoles. UV stabilizers and UV absorbers may be present in the organic peroxide formulation in a weight ratio relative to the organic peroxide of 0.0005 to 0.01. As an example of a coupling agent (different from the above-mentioned silane component), monoalkyl titanates may be mentioned. Inorganic fillers such as silicon dioxide, aluminum oxide, talcum powder, calcium carbonate may be added to increase the mechanical strength of the polymeric material when the peroxide formulation is cross-linked, although nano clay is preferred because of the transparency it provides. Examples of plasticizers are paraffin or aromatic mineral oils, phthalates, azelate, adipic acid esters, etc. The antioxidant may be a phenol, a phosphate (ester) or a sulfur antioxidant. Alternatively or additionally, quinoline such as 1,2-dihydro-2,2,4-trimethylquinoline may be used as an antioxidant. Organic or mineral pigments may also be added to color the polymer composition in which the formulation is intended to be used. Titanium dioxide may be mentioned in particular, which makes it possible to produce a white color, which may be particularly useful when the formulation is used in a polymer composition such as the following, which is used to manufacture a film intended for the back of a photovoltaic module. Examples of free radical scavengers suitable for the present invention are those selected from nitroxide free radicals (particularly 4-hydroxy-TEMPO) and quinones. As used herein, the term "quinone" includes both quinones and hydroquinones. Non-limiting examples of quinones that can be used in the formulations of the present invention include mono-tert-butylhydroquinone (MTBHQ), hydroquinone, hydroquinone monomethyl ether (HQMME) (also known as 4-methoxyphenol), mono-tert-amylhydroquinone, hydroquinone bis(2-hydroxyethyl) ether, 4-ethoxyphenol, 4-phenoxyphenol, 4-(benzyloxy)phenol, 2,5-bis(morpholinomethyl)hydroquinone, and benzoquinone.

[0112] The organic peroxide formulation may consist essentially of, or consist of, at least one organic peroxide, at least one drying oil, at least one silane component, at least one auxiliary agent, and optionally one or more additives selected from UV stabilizers, UV absorbers, coupling agents, fillers, plasticizers, flame retardants, antioxidants, dyes and pigments, free radical scavengers, and combinations thereof.

[0113] The organic peroxide formulation may comprise a free radical scavenger selected from the group consisting of nitroxide free radicals, quinones, and mixtures thereof.

[0114] The organic peroxide formulation may comprise the free radical scavenger in a weight ratio of free radical scavenger to organic peroxide of from 0 to 0.5, more preferably from 0 to 0.15, even more preferably from 0 to 0.05, even more preferably from 0 to 0.002.

[0115] The organic peroxide formulation may comprise a total amount of nitroxide free radical and quinone free radical scavenger in a weight ratio relative to the organic peroxide of from 0 to 0.5, more preferably from 0 to 0.15, more preferably from 0 to 0.05, even more preferably from 0 to 0.002.

[0116] When two or more organic peroxides are present in the organic peroxide formulation, the weight ratio of the free radical scavenger to the organic peroxide is based on the total weight of the organic peroxides.

[0117] In certain advantageous embodiments, the organic peroxide formulation does not comprise (ie, is free of) 4-hydroxyTEMPO and / or MTBHQ, and more particularly, does not comprise nitroxide free radicals and / or quinone-based free radical scavengers.

[0118] The organic peroxide formulation may be free of any free radical scavengers.

[0119] Polymer composition

[0120] The present invention also relates to a composition comprising at least one polymer and the above-described organic peroxide formulation (such composition is also referred to herein as a "polymer composition").

[0121] Therefore, the present invention particularly relates to a composition comprising:

[0122] - at least one polymer,

[0123] - at least one organic peroxide having a one-hour half-life temperature of from 90°C to 130°C,

[0124] - at least one dry oil, and

[0125] - optionally at least one silane component,

[0126] Wherein, the weight ratio of the drying oil to the organic peroxide is less than or equal to 0.60.

[0127] The components of the organic peroxide formulation (organic peroxide, drying oil, optional silane component, optional adjuvant, optional other additives, optional free radical scavenger), and their weight ratios may be as described in the previous section.

[0128] The polymer of the polymer composition of the present invention is preferably an ethylene polymer. The ethylene polymer may be an ethylene homopolymer, or preferably an ethylene copolymer. Examples of ethylene copolymers are those made from ethylene monomers and at least one other monomer selected from the following: hydrocarbons having at least one degree of unsaturation, such as methylene, propylene, butylene, pentene, hexene, heptene, octene, butadiene, isoprene and styrene; acrylic monomers such as acrylic acid, methacrylic acid, alkyl methacrylates and alkyl acrylates, wherein the alkyl group may be selected from, for example, methyl, ethyl, propyl or butyl; and vinyl monomers such as vinyl acetate and vinyl butyrate. Often, these copolymers contain at least 30% by weight of ethylene and up to 70% by weight of other monomers.

[0129] Thus, the polymer may advantageously be a copolymer of ethylene and at least one vinyl monomer, and is preferably a poly(ethylene-vinyl acetate) copolymer (EVA).

[0130] The EVA copolymer may contain from 15 to 60% by weight, preferably from 25 to 45% by weight, of units derived from vinyl acetate (VA) monomers. Examples of such EVA copolymers are available from ARKEMA under the trade name “ 18-150" and " 40-55” available.

[0131] Other ethylene polymers that can be used in the present invention are disclosed in, for example, EP 2242647. They include functionalized polyolefins, such as homopolymers of ethylene or copolymers of ethylene with alkyl (meth) acrylates or vinyl acetate, which can be functionalized by using maleic anhydride or glycidyl methacrylate, either copolymerized or grafted. Such functionalized polyolefins can optionally be mixed with copolymers of ethylene / carboxylic acid vinyl esters, such as EVA.

[0132] Alternatively, or additionally, the polymer may advantageously be a polyolefin elastomer (comprising or not comprising units derived from ethylene).

[0133] "Polyolefin" in the sense of the present invention means polymers derived from olefins such as ethylene, propylene, butene, hexene and the like.

[0134] The term "derived from [a (one) monomer]" means that the polymer contains units produced by polymerization or copolymerization of at least the monomer in its main chain and / or its adjacent chains (or vertical chains).

[0135] "Polyolefin elastomer" (POE) in the sense of the present invention means an elastomeric polymer derived from olefins (eg ethylene, propylene, butene, hexene, etc.).

[0136] "Elastomer" in the sense of the present invention is understood to mean a polymer which is able to undergo a uniaxial deformation of preferably at least 20% at ambient temperature (e.g. 20° C.) within a period of fifteen minutes and to regain its original shape when such stress is no longer applied, preferably wherein the residual deformation is less than 5% relative to its initial shape.

[0137] The polyolefin elastomer according to the invention is advantageously derived from ethylene. In other words, the polyolefin elastomer preferably comprises at least one unit derived from ethylene.

[0138] The polyolefin elastomer according to the present invention preferably further comprises units derived from at least one α-olefin.

[0139] Based on the total weight of the polymer, the polyolefin elastomer preferably comprises the following content: at least 15% by weight of units derived from alpha-olefins, preferably at least 20% by weight, and more preferably at least 25% by weight. Based on the total weight of the polymer, the polyolefin elastomer preferably comprises less than 50% by weight, preferably less than 45% by weight, and more preferably less than 35% by weight of the content of alpha-olefin units. Therefore, based on the total weight of the polymer, the polyolefin elastomer may comprise from 15% by weight to 50% by weight, preferably from 15% by weight to 45% by weight, more preferably from 15% by weight to 35% by weight, and even more preferably from 20% by weight to 35% by weight of the content of alpha-olefin units. The content of alpha-olefin units in the polymer can be determined by carbon-13 nuclear magnetic resonance (NMR) spectroscopy according to the scheme described by Randall (J.Macromol.Sci.:Rev.Macromol.Chem.Phys., C29 (2 and 3), 201-317, 1989).

[0140] The α-olefin is preferably C 3 -C 20 α-olefin. It can be linear, branched or cyclic. α-olefin is preferably linear or branched C 3 -C 20 α-Olefins.

[0141] The polyolefin elastomer is advantageously a copolymer of ethylene and at least one α-olefin, in particular a linear or branched C 3 -C 20α-olefins, excluding any other comonomers.

[0142] C 3 -C 20 The α-olefin is preferably selected from propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene and 1-octadecene.

[0143] Preferably, the polyolefin elastomer comprises or consists of units derived from ethylene and units derived from an α-olefin selected from 1-butene, 1-hexene and 1-octene.

[0144] The α-olefins may also contain cyclic structures, for example cyclohexane or cyclopentane structures, which lead to α-olefins such as 3-cyclohexyl-1-propene (allylcyclohexane) or vinylcyclohexane.

[0145] Certain cyclic olefins, such as norbornene and corresponding olefins, are considered alpha-olefins within the meaning of this invention and may be used in place of the alpha-olefins described above.

[0146] Preferably, at least one organic peroxide is present in the polymer composition in an amount of from 0.05 to 20 parts by weight, based on 100 parts by weight of the polymer (preferably ethylene polymer). More preferably, the organic peroxide is present in the polymer composition in an amount of from 0.1 to 3 parts by weight, even more preferably from 0.3 to 1.5 parts by weight, even more preferably from 0.3 to 1.3 parts by weight, based on 100 parts by weight of the polymer.

[0147] At least one drying oil may advantageously be present in the polymer composition in an amount of from 0.005 to 10 parts by weight, preferably from 0.01 to 5 parts by weight, even more preferably from 0.02 to 1 part by weight, calculated on 100 parts by weight of polymer, preferably ethylene polymer.

[0148] When present, at least one silane component may preferably be present in the polymer composition in an amount of from 0.01 to 20 parts by weight (based on 100 parts by weight of the polymer (preferably an ethylene polymer)), more preferably from 0.05 to 5 parts by weight, even more preferably from 0.1 to 1 part by weight, based on 100 parts by weight of the polymer.

[0149] When present, at least one adjuvant may be included in the polymer composition in an amount of 0.005 to 10 parts by weight, preferably from 0.01 to 5 parts by weight, more preferably from 0.05 to 2 parts by weight, even more preferably from 0.1 to 1 part by weight, based on 100 parts by weight of the polymer (preferably ethylene polymer).

[0150] Other additives, which are preferably selected from UV stabilizers, UV absorbers, coupling agents, fillers, plasticizers, flame retardants, antioxidants, dyes and pigments, free radical scavengers and mixtures thereof, may be present in the polymer composition.

[0151] The polymer composition of the present invention may consist essentially of or consist of at least one polymer (preferably an ethylene polymer), at least one organic peroxide, at least one drying oil, optionally at least one silane component, optionally at least one auxiliary agent, and optionally additives (preferably selected from UV stabilizers, UV absorbers, coupling agents, fillers, plasticizers, flame retardants, antioxidants, dyes and pigments, free radical scavengers and mixtures thereof).

[0152] In certain embodiments, the polymer composition is free of 4-hydroxy TEMPO and / or MTBHQ, and more particularly, free of nitroxide radicals and / or quinone-based radical scavengers.The polymer composition may be free of radical scavengers.

[0153] Preparation method

[0154] The invention also relates to a process for preparing the above-mentioned organic peroxide formulation, comprising mixing at least one organic peroxide and at least one drying oil and optionally other components of the formulation (such as at least one silane component, at least one auxiliary agent and / or other additives).

[0155] The mixing step may be performed in one or more steps (thus, some of the components may be pre-mixed before being mixed with other components of the formulation). The mixing step may be performed using any kind of equipment suitable for mixing formulations containing mainly liquids.

[0156] The mixing step is preferably carried out at a temperature below the decomposition temperature of the organic peroxide. It can be carried out at a temperature from -10°C to 50°C, preferably from 10°C to 40°C.

[0157] The present invention also relates to a method for preparing the above polymer composition. The method comprises the step of mixing at least one polymer with the above organic peroxide formulation. The polymer can be mixed with the previously prepared organic peroxide formulation, or can be mixed in one or more steps with any or each component of the organic peroxide formulation and / or any premix of the components of the organic peroxide formulation.

[0158] The mixing step can be carried out in any conventional device, such as a continuous mixer, a batch mixer, a blending extruder, or directly in the barrel of the film extrusion line. The temperature of the mixing step is preferably below the decomposition temperature of the peroxide. In particular, the mixing step can be carried out at a temperature ranging from -10 to 120°C, preferably from 10 to 120°C.

[0159] Preferably, the method further comprises an impregnation step after the mixing step. In such an impregnation step, the polymer (preferably in the form of particles) is allowed to stand after mixing with the peroxide organic formulation, preferably for at least 1 hour, so that the organic peroxide impregnates the polymer particles.

[0160] In the above methods, the components and their amounts may be as described in the previous sections.

[0161] application

[0162] Another object of the present invention is the use of the above organic peroxide formulation for curing polymers, preferably ethylene polymers, more preferably polymers selected from poly(ethylene vinyl acetate), polyolefin elastomers and combinations thereof. Preferably, a polymer composition as described above is formed.

[0163] The polymer may be a polymer as described above.

[0164] The present invention also relates to a method for manufacturing an article, comprising the following steps:

[0165] - optionally providing a polymer composition as described above; and

[0166] - curing the composition.

[0167] The curing step is advantageously carried out at a temperature ranging from 120 to 250° C., preferably from 130 to 180° C., more preferably from 130 to 170° C., even more preferably from 130 to 165° C. It may last from 4 to 50 minutes, preferably from 6 to 35 minutes.

[0168] Advantageously, the curing step is carried out in the absence of oxygen.

[0169] By "in the absence of oxygen", it is meant that during the curing step, the curable composition is at least not intentionally in contact with oxygen. In other words, the curable composition is not substantially in the presence of oxygen during the curing step, and preferably, the curable composition is not in the presence of oxygen during the curing step.

[0170] Advantageously, the curing step is performed during the lamination step.

[0171] Preferably, the method further comprises the step of shaping the polymer composition. This step can be carried out before the solidification step and / or simultaneously with the solidification step. Advantageously, the step of shaping the polymer composition is selected from the forming step, extrusion step and injection molding step of the polymer composition. Preferably, it is an extrusion step.

[0172] Preferably, the step of shaping the polymer composition is carried out before the step of curing the polymer composition. Therefore, preferably no crosslinking or substantially no crosslinking occurs during the plastic step. When the plastic step is carried out before the curing step, the plastic step may be carried out at a temperature of from 80 to 150° C., more preferably from 90 to 120° C. Alternatively, the plastic step and the curing step may be carried out in a single step.

[0173] In certain embodiments, the produced article is a film (or sheet). In such an embodiment, the method comprises shaping the polymer composition to form a step of film. The step can be carried out using a T-die extruder, or alternatively, using a twin-screw extruder coupled to a double-roll grinder.

[0174] For example, the film may have a thickness of from 50 to 2000 microns, preferably from 100 to 1000 microns.

[0175] The articles produced by the above process can advantageously be selected from encapsulating materials, in particular potting agents for solar cells, wire and cable insulation, pipes and hoses (for example, including those for automotive radiators, drinking water and floor heating), roller coatings, rotational moldings, cellular articles and shoe soles.

[0176] Most preferably, the article is an encapsulation material, and more particularly, an encapsulant for a solar cell.

[0177] The present invention also relates to an article obtainable by or through the above method. The article may be as described above.

[0178] A further object of the invention is a photovoltaic module comprising an article as described above, preferably a film as described above. The photovoltaic module comprises one or more solar cells and the article according to the invention, preferably a film, is advantageously an encapsulant for the solar cells. Preferably, the film directly covers the solar cell(s), i.e. is in contact with the solar cell(s). The film according to the invention may cover both sides of the solar cell(s) or a single side of the solar cell(s), either the side towards the front of the photovoltaic module or the side towards the back of the photovoltaic module.

[0179] The photovoltaic module preferably further comprises a front sheet which can directly cover the film according to the invention and / or (preferably and) a back sheet which can directly cover the film according to the invention.

[0180] The front sheet is most preferably a transparent sheet. For example, it may be a glass sheet or a poly(methyl methacrylate) (PMMA) sheet.

[0181] The back sheet material can be, for example, a glass sheet (preferably a thin glass plate) or a PMMA plate. Alternatively, the back sheet material can be a multilayer structure (multilayer film), which preferably comprises or is composed of: a film of an electrically insulating polymer such as polyethylene terephthalate (PET) or polyamide (PA), one or more films based on fluoropolymers such as polyvinyl fluoride (PVF) or polyvinylidene fluoride (PVDF), and optionally a film of metal such as aluminum (layers are preferably in this order). The back sheet material is advantageously a multilayer PVDF / PET film. Alternatively, the multilayer structure of the back sheet material can comprise or be composed of: a glass sheet material and a film that can be obtained by curing the polymer composition of the present invention described above.

[0182] The solar unit cell is preferably a unit cell made of crystalline silicon or an organic photovoltaic material.

[0183] The present invention is also applicable to a method for manufacturing a photovoltaic module, the method comprising the following steps:

[0184] - Lamination of an assembly comprising, in order, at least:

[0185] ■ front sheet (such as glass sheet or PMMA sheet),

[0186] ■ a layer of a polymer composition according to the invention,

[0187] ■ at least one solar cell (preferably made of crystalline silicon or organic photovoltaic material),

[0188] ■ a further layer of a polymer composition according to the invention, and

[0189] ■Back sheet (such as multi-layer PVDF / PET film or glass sheet or PMMA sheet)

[0190] - Press laminated assembly.

[0191] The laminated assembly may be pressed by conventional techniques while heating and / or under vacuum, for example at a temperature of from 130 to 250° C., preferably from 130 to 180° C., more preferably from 140 to 165° C., under vacuum, for a time that may range from 4 to 40 minutes, for example from 6 to 35 minutes. The polymer composition of the invention may be crosslinked (or cured) during or after this pressing step. Preferably, the step of pressing the laminated assembly and the step of curing the polymer composition are simultaneous.

[0192] Example

[0193] The following examples illustrate the present invention but do not limit it.

[0194] Example 1

[0195] By POE polymer (14MI, from DOW Chemical Company), 0.75 phr OO-tert-butyl-O-2-ethylhexyl-monoperoxycarbonate (TBEC) ( The first base composition was prepared by mixing 0.3 phr of 3-methacryloxypropyltrimethoxysilane (TBEC, from Arkema), 0.3 phr of 3-methacryloxypropyltrimethoxysilane (KH-570, from Sigma-Aldrich) and 0.5 phr of triallyl isocyanurate (TAIC) (from Ourchem) in a 125 mL bottle. The mixture was then heated in an oven at 40° C. for 7.5 hours. During the heating step, the mixture needed to be shaken every 2-3 hours.

[0196] Phr means "parts per hundred rubber", and thus in the present example means "parts by weight per 100 parts of polymer POE".

[0197] OO-tert-butyl-O-2-ethylhexyl-monoperoxycarbonate has a one hour half-life temperature of 121°C.

[0198] A second base composition was prepared in the same manner as the first base composition except that 0.75 phr of 0-tert-amyl O-(2-ethylhexyl) monoperoxycarbonate (TAEC) ( TAEC, available from Arkema) was used in place of 0.75 phr of TBEC.

[0199] OO-tert-Amyl O-(2-ethylhexyl)monoperoxycarbonate has a one hour half-life temperature of 117°C.

[0200] As shown in the following table, a certain amount of tung oil (from Anhui Refined Oil and Fat Co., Ltd.), odorless mineral spirit (synthetic isoparaffinic hydrocarbons, from Idemitsu kosan Co., Ltd.) or refined tung oil (from Anhui Refined Oil and Fat Co., Ltd.) was added to these base compositions. The tung oil used in the examples had a saponification value of 193 (determined according to GB / T5534-1995) and an iodine value of 167 g / 100 g (determined according to GB / T5532-2008).

[0201] [Table 1]

[0202]

[0203] Composition Nos. 3, 4, 5, 6, 7 and 9 are compositions according to the present invention; Composition Nos. 1, 2 and 8 are comparative compositions. Composition Nos. 1 to 7 comprise TBEC as the organic peroxide; Compositions 8 and 9 comprise TAEC as the organic peroxide.

[0204] The sample of about 2 to 3 grams of the composition produced in this way is placed on the plate on the rubber processing analyzer (RPA) of the model type EKT-2003RPA-N of EKTRON TEK.CO., LTD, which can measure the curing properties of the sample, and comprises a software for analyzing the results. Each of the samples is placed in a temperature-controlled cavity between two plates, and the plate vibration at its bottom is to apply cyclic stress or strain to the sample, and the die head at the top is connected to a torque sensor to measure the torque response of the sample to deformation. Under this condition, the sample surface is protected from the presence of air (and therefore oxygen) by the metal surface of the plate. The change of rigidity over time is recorded continuously. The rigidity of the sample increases along with crosslinking.

[0205] In particular, RPA can provide L (minimum torque), M H (maximum torque), t S1 (time from minimum torque to torque increase of 1dN.m) and tc 90 (reaching 90% of M H -M L The calculated value of the time of the cured state) as defined in international standards (such as ASTM D5289). s1 represents the scorch time. From these data, the relative degree of crosslinking M can be determined H -M L (or cross-link density).

[0206] The RPA was operated at 145°C with an oscillation amplitude (degree of deformation) of 0.5°, an oscillation frequency of 1.667 and a strain value of 7 applied to the sample for 30 minutes, except for Examples 10 and 11 where the test was conducted for 45 minutes.

[0207] The results are shown in the table below.

[0208] [Table 2]

[0209]

[0210] The compositions of the present invention comprising tung oil resulted in longer scorch times compared to compositions containing no oil or containing mineral spirits. Thus, tung oil is effective as a scorch protection agent. Furthermore, the crosslink density obtained using the compositions of the present invention is not compromised, and t c90The results are shown in Table 1. The results are shown in Table 2. The results are shown in Table 3. The results are shown in Table 4. The results are shown in Table 5. The results are shown in Table 6. The results are shown in Table 7. The results are shown in Table 8. The results are shown in Table 9. The results are shown in Table 10. The results are shown in Table 11. The results are shown in Table 12.

[0211] Example 2

[0212] By EVA polymer (V2825 from JiangSu Sailboat Petrochemical), 0.6phr TBEC (Luperox ), 0.3 phr of 3-methacryloxypropyltrimethoxysilane (KH-570 from Sigma-Aldrich) and 0.5 phr of TAIC (from Ourchem) were mixed in a 125 mL bottle to prepare the first base composition. The mixture was then heated in an oven at 40° C. for 6.5 h. During the heating step, the mixture needed to be shaken every 2-3 hours.

[0213] In the present embodiment, phr means "parts by weight based on 100 parts of polymer EVA".

[0214] Another base composition was prepared in the same manner except that 0.6 phr of 0-tert-amyl O-(2-ethylhexyl) monoperoxycarbonate (TAEC) ( TAEC, available from Arkema) was substituted for 0.6 phr of TBEC.

[0215] Yet another base composition was prepared in the same manner as the first base composition, except that 1.2 phr of TAEC ( TAEC) replaced 0.6 phr TBEC.

[0216] Yet another base composition was prepared in the same manner as the first base composition, except that 90 wt % TAEC ( TAEC) and 10 wt% tert-butyl peroxy 2-ethylhexanoate (TBPO) (from Arkema 26) instead of 0.6 phr of TBEC.

[0217] Tert-butyl peroxy 2-ethylhexanoate has a one hour half-life temperature of 95°C.

[0218] Yet another base composition was prepared in the same manner as the first base composition except that 0.75 of TBEC was used instead of 0.6 phr of TBEC.

[0219] To each of these compositions, tung oil or castor oil (Castor Oil from ADANI) was either added or not added as shown in the table below.

[0220] Castor oil, having an iodine value of 85 g / 100 g and a saponification index of 180 mg KOH / g, determined as described above.

[0221] [Table 3]

[0222]

[0223]

[0224] Composition Nos. 11, 13, 15, 17 and 19 are compositions according to the invention; Composition Nos. 10, 12, 14, 16, 18 and 20 are comparative compositions.

[0225] The crosslinking properties of composition Nos. 10 to 13 were determined as described in Example 1 with a curing time of 30 minutes.

[0226] The crosslinking properties of compositions No. 14 to 17 were determined as described in Example 1, but at three different temperatures: 145° C., 130° C. and 110° C. The RPA measurements were performed for 45 minutes. The temperatures of 145 and 130° C. simulate the conditions of the lamination process (e.g., for the manufacture of photovoltaic modules); the temperature of 110° C. simulates the conditions of the extrusion process (e.g., for forming a film before the lamination process).

[0227] The crosslinking properties of composition Nos. 18 to 20 were determined as described in Example 1 with a curing time of 45 minutes.

[0228] The results are shown in the following table.

[0229] [Table 4]

[0230]

[0231]

[0232] ND = Not Determined This indicates that no increase of 1 dN.m was achieved during the 45 minute duration of the measurement.

[0233] A significant increase in scorch time was observed with the compositions of the present invention at operating temperatures of 145°C and 130°C, compared to compositions without tung oil, regardless of the peroxide used, while the crosslink density remained good.

[0234] Furthermore, it can be seen that at an operating temperature of 110° C., little crosslinking occurs through the composition of the present invention. This is desirable because during the extrusion step in which the composition is shaped, crosslinking preferably does not occur or substantially does not occur. In contrast, the comparative composition exhibits a higher crosslink density at 110° C., indicating that the presence of tung oil makes it possible to reduce crosslinking at a temperature of 110° C.

[0235] Comparing Example 20 with Examples 18 and 19, no scorch protection was observed when castor oil was used, and the crosslink density was even lower than the counterexample without any oil.

Claims

1. An organic peroxide formulation comprising: at least one organic peroxide having a one-hour half-life temperature of from 90° C. to 130° C., preferably from 110° C. to 125° C., and - at least one drying oil, The weight ratio of the drying oil to the organic peroxide is less than or equal to 0.

60.

2. The organic peroxide formulation according to claim 1, wherein the at least one drying oil has an iodine value of from 125 to 215 g / 100 g, preferably from 140 to 205 g / 100 g, more preferably from 150 to 180 g / 100 g.

3. The organic peroxide formulation according to claim 1 or 2, wherein the at least one drying oil has a saponification value of from 175 to 210 mg KOH / g, preferably from 182 to 195 mg KOH / g.

4. The organic peroxide formulation of any one of claims 1 to 3, wherein the at least one drying oil is selected from tung oil, hemp oil, linseed oil, poppy seed oil, walnut oil, sunflower oil, cottonseed oil, corn oil, soybean oil, fish oils such as sardine oil and cod liver oil, herring oil, safflower oil, linseed oil, perilla oil, oatmeal oil, and combinations thereof, preferably the at least one drying oil is tung oil.

5. The organic peroxide formulation according to any one of claims 1 to 4, wherein the at least one organic peroxide is selected from the group consisting of diperoxyketals, peroxyketals, monoperoxycarbonates, cyclic ketone peroxides, diacyl peroxides, organic sulfonyl peroxides, peroxyesters, peroxydicarbonates and combinations thereof, preferably selected from the group consisting of diperoxyketals, peroxyketals, monoperoxycarbonates, peroxyesters and combinations thereof, more preferably selected from the group consisting of OO-tert-butyl-O-(2-ethylhexyl)-monoperoxycarbonate, OO-tert-butyl-O-2-isopropyl-monoperoxycarbonate, OO-tert-amyl-O-(2-ethylhexyl)-monoperoxycarbonate, OO-tert-amyl-O-2-isopropyl-monoperoxycarbonate, OO-tert-hexyl-O-(2-ethylhexyl)-monoperoxycarbonate and mixtures thereof, optionally in combination with at least one other peroxide.

6. The organic peroxide formulation according to any one of claims 1 to 5, further comprising at least one silane component, the at least one silane component is preferably selected from vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane and mixtures thereof, and more preferably 3-methacryloxypropyltriethoxysilane or / and 3-methacryloxypropyltrimethoxysilane.

7. The organic peroxide formulation according to any one of claims 1 to 6, wherein the weight ratio of the drying oil to the organic peroxide is lower than or equal to 0.45, preferably from 0.025 to 0.45, more preferably from 0.03 to 0.3, more preferably from 0.03 to 0.25, and even more preferably from 0.05 to 0.

2.

8. The organic peroxide formulation according to any one of claims 1 to 7, further comprising at least one auxiliary, preferably selected from triallyl cyanurate, triallyl isocyanurate, N,N'-m-phenylenedimaleimide, triallyl trimellitate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trivinylcyclohexane and mixtures thereof.

9. The organic peroxide formulation according to any one of claims 1 to 8, comprising at least the following combination: 1) a monoperoxycarbonate, the monoperoxycarbonate preferably being selected from the group consisting of OO-tert-butyl-O-(2-ethylhexyl)-monoperoxycarbonate, OO-tert-butyl-O-2-isopropyl-monoperoxycarbonate, OO-tert-amyl-O-(2-ethylhexyl)-monoperoxycarbonate, OO-tert-amyl-O-2-isopropyl-monoperoxycarbonate, OO-tert-hexyl-O-(2-ethylhexyl)-monoperoxycarbonate and mixtures thereof, and 2) a peroxyester, the peroxyester preferably being selected from the group consisting of tert-butyl peroxy-2-ethylhexanoate and tert-amyl peroxy-2-ethylhexanoate, More preferred is a combination of 0-tert-amyl-0-(2-ethylhexyl)-monoperoxycarbonate and tert-butylperoxy-2-ethylhexanoate.

10. Composition comprising at least one polymer and the organic peroxide formulation according to any one of claims 1 to 9.

11. The composition of claim 10, wherein the at least one polymer is an ethylene polymer, in particular poly(ethylene vinyl acetate) and / or a polyolefin elastomer.

12. The composition of claim 10 or 11, wherein the amount of the at least one drying oil in the composition is from 0.005 to 10 parts by weight, preferably from 0.01 to 5 parts by weight, more preferably from 0.02 to 1 part by weight, based on 100 parts by weight of the at least one polymer.

13. A process for preparing the organic peroxide formulation according to any one of claims 1 to 9, said process comprising mixing said at least one organic peroxide and said at least one drying oil.

14. A method of making an article, the method comprising the step of curing the composition of any one of claims 10 to 12.

15. Article, in particular a film, obtainable by the process according to claim 14.

16. Use of the organic peroxide formulation according to any one of claims 1 to 9 for curing a polymer, preferably selected from the group consisting of poly(ethylene vinyl acetate), polyolefin elastomers and combinations thereof.

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