Irradiation-crosslinkable silicone composition comprising pt(octane-2,4-dione)2 as a catalyst

Abstract

The present invention relates to a silicone composition X which is cross-linkable by polyaddition reactions to form a silicone elastomer. In particular, the present invention relates to a silicone composition X crosslinkable by photon irradiation catalyzed by C, which is Pt(octane-2,4-dione)2.

Description

Radiation-crosslinkable silicone composition comprising Pt(octane-2,4-dione)2 as catalyst Technical field

[0001] The present invention relates to a silicone composition X crosslinkable by polyaddition reactions to form a silicone elastomer. In particular, the present invention relates to a silicone composition X crosslinkable by photonic irradiation catalyzed by a hydrosilylation catalyst C which is Pt(octane-2,4-dione)2. Technological background

[0002] Silicone compositions crosslinkable by polyaddition reactions are generally crosslinked thermally in the presence of a platinum catalyst, in particular the Karstedt catalyst. However, for several years, compositions crosslinkable by irradiation have been developed. This type of composition crosslinkable by irradiation is particularly useful for "coating" type applications, where a support is covered with a silicone coating. In addition, this type of process has advantages because it is less energy-intensive than the thermal process, which allows for cost savings. This is particularly true when irradiation is carried out by UV-LED systems.

[0003] Patent application WO9525734 describes photoactive organoplatinum complexes for crosslinking by hydrosilylation of organopolysiloxane SiH and SiVi. These photoactive organoplatinum complexes are prepared by reacting a photosensitive ligand with the Karstedt complex. However, the systems described in this application do not allow to obtain both good reactivity under UV (rapid crosslinking under irradiation), and good stability of the composition without irradiation (long gel time without irradiation). The organoplatinum complexes described may also have solubility problems in silicone compositions.

[0004] It is also known, for example in European patent EP 0398701, to use Pt(acetylacetonate)2 (or Pt(acac)2) as a hydrosilylation catalyst for radiation-crosslinkable silicone compositions. However, Pt(acetylacetonate)2 is suspected of damaging fertility or the fetus (H361 -CMR Reprotoxic Cat. 2).

[0005] Furthermore, the systems described above are not necessarily usable when irradiation is carried out by UV-LED systems. Indeed, working with a largely monochromatic light source such as LEDs requires a more precise design of the photocatalytic system in order to maximize the efficiency of photon absorption, and therefore the responsiveness of the system.

[0006] It is therefore necessary to develop photocatalytic systems that can overcome these disadvantages.

[0007] In this context, the present invention aims to satisfy at least one of the following objectives. One of the objectives of the invention is the provision of a composition crosslinkable under UV irradiation, and in particular LIV-LED.

[0008] Another objective of the invention is the provision of a composition which can be crosslinked under irradiation and which is catalyzed by a compound which is of low or no toxicity.

[0009] Another objective of the invention is the provision of a composition which can be crosslinked under irradiation and which has good reactivity.

[0010] Another objective of the invention is the provision of a composition crosslinkable under irradiation having good stability without irradiation.

[0011] Another objective of the invention is the provision of a photocatalytic system having good solubility in silicone compositions. Brief description of the invention

[0012] These objectives, among others, are achieved by the present invention which relates firstly to a radiation-crosslinkable silicone composition X comprising: a. at least one organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups bonded to silicon; b. at least one organopolysiloxane B having, per molecule, at least two SiH units; and c. a catalytically effective amount of at least one hydrosilylation catalyst C, which is Pt(octane-2,4-dione)2.

[0013] Surprisingly, the inventors demonstrated that, unlike Pt(acac)2, Pt(octane-2,4-dione)2 had the advantage of not being mutagenic. Indeed, this compound was analyzed according to the Ames test: the Ames test is a widely used method that uses bacteria to check whether a given chemical can cause mutations in the DNA of the tested organism. Unexpectedly, the Ames test was conclusive: Pt(octane-2,4-dione)2 did not induce any mutagenic changes in the tested microorganisms.

[0014] In addition, the use of a catalyst C which is Pt(octane-2,4-dione)2 makes it possible to increase the reactivity of the silicone composition X under irradiation, and in particular under UV-LED irradiation. The silicone composition X therefore crosslinks more quickly than with Pt(acac)2 or other Pt[3-diketonate] complexes. Finally, the silicone composition X has high stability when not irradiated. Thus, it is possible to keep the non-crosslinked silicone composition X away from light for several dozen days.

[0015] Catalyst C, which is Pt(octane-2,4-dione)2, also exhibits very good solubility in silicone compositions. This solubility is, for example, higher than for other Pt p-diketonate complexes, which is an advantage.

[0016] Thus, composition X according to the invention has many advantages: it has good stability and good reactivity, and catalyst C, which is Pt(octane-2,4-dione)2, has good solubility in silicone compositions and is not a mutagenic compound according to the Ames test.

[0017] The present invention also relates to a method for preparing a coating on a support, comprising the following steps: - application of a silicone composition X to a support, preferably a textile support, and - crosslinking of said composition by electronic or photonic irradiation, preferably by exposure to an electron beam, by exposure to gamma rays, or by exposure to radiation with a wavelength between 100 nm and 450 nm, in particular to UV radiation.

[0018] The present invention also relates to a coated support capable of being obtained according to said method.

[0019] The present invention also relates to the use of silicone composition X for the preparation of silicone elastomers.

[0020] The present invention also relates to a premix for a silicone composition comprising: - at least one organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups linked to silicon, - at least one hydrosilylation catalyst C which is Pt(octane-2,4-dione)2. Definitions

[0021] In the present application, the term "irradiation-crosslinkable silicone composition" means a silicone composition comprising at least one organopolysiloxane capable of curing by electronic or photonic irradiation. Among electronic irradiations, mention may be made of exposure to an electron beam. Among photonic irradiations, mention may be made of exposure to UV radiation or exposure to gamma rays. Preferably, the irradiation is carried out by exposure to a radiation with a wavelength between 100 nm and 450 nm, or between 200 nm and 405 nm.

[0022] In this text, "UV" means ultraviolet. Ultraviolet radiation is defined as electromagnetic radiation with a wavelength between about 100 nm and about 405 nm, which is below the visible light spectrum.

[0023] Furthermore, in this text, “LED” is the abbreviation well known to those skilled in the art for “light-emitting diode” (also DEL in French).

[0024] Unless otherwise indicated, all viscosities of the silicone oils referred to in this disclosure correspond to a dynamic viscosity quantity at 25°C known as “Newtonian”, i.e. the dynamic viscosity which is measured, in a manner known per se, with a Brookfield viscometer at a shear rate gradient sufficiently low so that the measured viscosity is independent of the rate gradient.

[0025] In this description, the term "textile" is a generic term encompassing all textile structures. Textiles may consist of yarns, fibers, filaments and / or other materials. They include, in particular, flexible fabrics, whether woven, bonded, knitted, braided, felted, needled, sewn, or made by another manufacturing method. By "yarn" is meant, for example, a continuous multifilament object, a continuous yarn obtained by assembling several yarns or a continuous fiber yarn, obtained from a single type of fiber, or from a mixture of fibers. By "fiber" is meant, for example, a short or long fiber, a fiber intended to be worked in spinning or for the manufacture of non-woven articles or a tow intended to be cut to form short fibers.The textile may perfectly well be made up of threads, fibres and / or filaments having undergone one or more treatment stages before the creation of the textile surface, such as for example stages of texturising, stretching, stretch-texturising, sizing, relaxing, heat-fixing, twisting, fixing, crimping, washing and / or dyeing.

[0026] In this application, all % and ppm are by weight unless otherwise stated. Detailed description

[0027] Crosslinkable silicone composition X

[0028] The subject of the present invention is a silicone composition X crosslinkable by irradiation comprising: a. at least one organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups linked to silicon; b. at least one organopolysiloxane B having, per molecule, at least two SiH units; and c. a catalytically effective amount of at least one hydrosilylation catalyst C; which is Pt(octane-2,4-dione)2.

[0029] According to one embodiment, composition X is crosslinkable by exposure to radiation with a wavelength between 100 nm and 450 nm, in particular to UV radiation.

[0030] Organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups linked to silicon, can in particular be formed: - at least two siloxyl units of the following formula: Y a R 1 bSiO(4- a -b) / 2 in which: Y is C2-C12 alkenyl, preferably vinyl, R 1is a monovalent hydrocarbon group having from 1 to 12 carbon atoms, preferably selected from alkyl groups having from 1 to 8 carbon atoms such as methyl, ethyl, propyl groups, optionally substituted by at least one halogen atom such as chlorine or fluorine, cycloalkyl groups having from 3 to 8 carbon atoms and aryl groups having from 6 to 12 carbon atoms, and a=1 or 2, b=0, 1 or 2 and the sum a+b=1, 2 or 3; and - possibly patterns of the following formula: R 1 c SiO(4- C ) / 2 in which R 1 has the same meaning as above and c = 0, 1, 2 or 3.

[0031] It is understood in the above formulas that, if several R groups 1 are present, they can be the same or different from each other.

[0032] These organopolysiloxanes A can have a linear structure, essentially consisting of siloxyl units “D” chosen from the group consisting of the siloxyl units Y2SiC>2 / 2, YR 1 SiC>2 / 2 and R 1 2SiC>2 / 2, and terminal “M” siloxyl units chosen from the group consisting of the YR siloxyl units 1 2SiOi / 2, Y2R 1 SiOi / 2 and R 1 3SiOi / 2. The symbols Y and R 1 are as described above.

[0033] Examples of terminal “M” units include trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy or dimethylhexenylsiloxy groups.

[0034] Examples of “D” units include dimethylsiloxy, methylphenylsiloxy, diphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyldecenylsiloxy or methyldecadienylsiloxy groups.

[0035] Examples of organopolysiloxanes which may be organopolysiloxanes A according to the invention are: - a poly(dimethylsiloxane) with dimethylvinylsilyl ends; - a poly(dimethylsiloxane-co-methylphenylsiloxane) with dimethyl-vinylsilyl ends; - a poly(dimethylsiloxane-co-methylvinylsiloxane) with dimethyl-vinylsilyl ends; - a poly(dimethylsiloxane-co-methylvinylsiloxane) with trimethylsilyl ends; and - a cyclic poly(methylvinylsiloxane).

[0036] In the most preferred form, organopolysiloxane A contains terminal dimethylvinylsilyl units and even more preferably organopolysiloxane A is a poly(dimethylsiloxane) with dimethylvinylsilyl ends.

[0037] A silicone oil generally has a viscosity of between 1 mPa.s and 2,000,000 mPa.s. Preferably, said organopolysiloxanes A are oils with a dynamic viscosity of between 20 mPa.s and 300,000 mPa.s, preferably between 100 mPa.s and 200,000 mPa.s at 25°C, and more preferably between 600 mPa.s and 150,000 mPa.s.

[0038] Optionally, the organopolysiloxanes A may further contain siloxyl units “T” (R 1 SiC>3 / 2) and / or siloxyl units “Q” (SiO4 / 2). The symbols R 1 are as described above. The organopolysiloxanes A then have a branched structure. Examples of branched organopolysiloxanes which may be organopolysiloxanes A according to the invention are: - a poly(dimethylsiloxane)(methylsiloxane) with trimethylsilyl and dimethylvinylsilyl ends, consisting of “M” trimethylsiloxy, “M” dimethylvinylsiloxy, “D” dimethylsiloxy and “T” methylsiloxy units; - a resin consisting of “M” trimethylsiloxy, “M” dimethylvinylsiloxy and “Q” units; and - a resin consisting of “M” trimethylsiloxy, “D” methylvinylsiloxy and “Q” units.

[0039] However, according to one embodiment, the silicone composition X does not comprise branched organopolysiloxanes or resins comprising C2-C12 alkenyl units.

[0040] Preferably, the organopolysiloxane compound A has a mass content of alkenyl unit of between 0.001% and 30%, preferably between 0.01% and 10%, preferably between 0.02 and 5%.

[0041] The silicone composition X preferably comprises from 50% to 95% of organopolysiloxane A, more preferably from 60% to 87% by weight of organopolysiloxane A, and even more preferably from 70% to 85% by weight of organopolysiloxane A relative to the total weight of the silicone composition X.

[0042] The silicone composition X may comprise a single organopolysiloxane A or a mixture of several organopolysiloxanes A having, for example, different viscosities and / or different structures.

[0043] Organopolysiloxane B is an organohydrogenpolysiloxane compound comprising per molecule at least two, and preferably at least three, hydrogenosilyl functions or Si-H units.

[0044] The organohydrogenpolysiloxane B may advantageously be an organopolysiloxane comprising at least two, preferably at least three, siloxyl units of the following formula: HdR 2 e SiO(4-de) / 2 in which: - the R radicals 2 , identical or different, represent a monovalent radical having from 1 to 12 carbon atoms, - d=1 or 2, e=0, 1 or 2 and d+e=1, 2 or 3; and possibly other patterns of the following formula: R 2 fSiO(4-f) / 2 in which R 2has the same meaning as above, and f = 0, 1, 2, or 3.

[0045] It is understood in the above formulas that, if several R groups 2 are present, they can be identical or different from each other. Preferably R 2 may represent a monovalent radical selected from the group consisting of alkyl groups having 1 to 8 carbon atoms, optionally substituted by at least one halogen atom such as chlorine or fluorine, cycloalkyl groups having 3 to 8 carbon atoms and aryl groups having 6 to 12 carbon atoms. R 2 may advantageously be selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl.

[0046] In the above formula, the symbol d is preferably equal to 1.

[0047] Organohydrogenpolysiloxane B may have a linear, branched, or cyclic structure. The degree of polymerization is preferably greater than or equal to 2. Generally, it is less than 5000.

[0048] When it comes to linear polymers, these are essentially made up of siloxyl units chosen from the units of the following formulas D: R 2 2SiC>2 / 2 or D': R 2 HSiC>2 / 2, and terminal siloxyl units chosen from the units of the following formulas M: R 2 3SiOi / 2 or M': R 2 2HSiOi / 2 where R 2 has the same meaning as above.

[0049] Examples of organohydrogenpolysiloxanes which may be organopolysiloxanes B according to the invention comprising at least two hydrogen atoms linked to a silicon atom are: - a poly(dimethylsiloxane) with hydrogenodimethylsilyl ends; - a poly(dimethylsiloxane-co-methylhydrogensiloxane) with trimethylsilyl ends; - a poly(dimethylsiloxane-co-methylhydrogensiloxane) with hydrogen-dimethylsilyl ends; - a poly(methylhydrogensiloxane) with trimethylsilyl ends; and - a cyclic poly(methylhydrogensiloxane).

[0050] When the organohydrogenpolysiloxane B has a branched structure, it is preferably chosen from the group consisting of silicone resins of the following formulae: - M'Q where the hydrogen atoms linked to silicon atoms are carried by the M groups, - MM'Q where the hydrogen atoms linked to silicon atoms are carried by part of the M motifs, - MD'Q where the hydrogen atoms linked to silicon atoms are carried by the D groups, - MDD'Q where the hydrogen atoms linked to silicon atoms are carried by part of the D groups, - MM'TQ where the hydrogen atoms linked to silicon atoms are carried by part of the M motifs, - MM'DD'Q where the hydrogen atoms linked to silicon atoms are carried by part of the M and D motifs, - and their mixtures, with M, M', D and D' as defined previously, T: siloxyl unit of formula R 2 aSiOi / 2 and Q: siloxyl unit of formula SiC>4 / 2 where R 2 has the same meaning as above.

[0051] Preferably, the organohydrogenpolysiloxane compound B has a mass content of hydrogenosilyl Si-H functions of between 0.2% and 91%, more preferably between 3% and 80%.

[0052] Considering the whole of the silicone composition X, the molar ratio of the hydrogenosilyl functions Si-H to the alkene functions can advantageously be between 0.2 and 20, preferably between 0.5 and 15, more preferably between 0.5 and 10, and even more preferably between 0.5 and 5.

[0053] Preferably, the viscosity of the organohydrogenpolysiloxane B is between 1 mPa.s and 5000 mPa.s, more preferably between 1 mPa.s and 2000 mPa.s and even more preferably between 5 mPa.s and 1000 mPa.s.

[0054] The silicone composition X preferably comprises from 0.1% to 10% of organohydrogenpolysiloxane B, and more preferably from 0.5% to 5% by weight, relative to the total weight of the silicone composition X.

[0055] The silicone composition X may comprise a single organohydrogenpolysiloxane B or a mixture of several organohydrogenpolysiloxanes B having, for example, different viscosities and / or different structures.

[0056] According to one embodiment, the silicone composition X may comprise a mixture: - at least one organohydrogenpolysiloxane B as described above comprising two Si H functions per molecule; and - at least one organohydrogenpolysiloxane B as described above comprising at least three SiH functions per molecule.

[0057] In the context of the invention, the hydrosilylation catalyst C is Pt(octane-2,4-dione)2. The weight quantity of catalyst C, calculated as the weight of platinum metal, is generally between 1 and 400 ppm, preferably between 2 and 200 ppm, and more preferably between 5 and 100 ppm, based on the total weight of the silicone composition X.

[0058] Pt(octane-2,4-dione)2 has two diastereomers, cis and trans

[0059] The cis:trans ratio in hydrosilylation catalyst C is between 0:100 and 100:0. Thus, it is possible to use as hydrosilylation catalyst C only the cis diastereomer, only the trans diastereomer, or a mixture of both diastereomers.

[0060] According to one embodiment, Pt(octane-2,4-dione)2 is a mixture of cis and trans diastereomer. The cis:trans ratio can be between 90:10 and 10:90, or between 75:25 and 25:75. According to a particular embodiment, the mixture mainly comprises the cis diastereomer.

[0061] Pt(octane-2,4-dione)2 can be synthesized by reacting the octane-2,4-dione ligand with a platinum precursor, such as F^PtCL, in the presence of a base, such as NaOH.

[0062] The silicone composition X according to the invention may contain a crosslinking inhibitor D. Crosslinking inhibitors are designed to slow down the crosslinking reaction and are also called retarders. Crosslinking inhibitors are well known in the art previous. Examples include cyclic polymethylvinylsiloxanes and acetylenic alcohols described in US Pat. No. 3,923,705, acetylenic alcohols described in US Pat. No. 3,445,420, heterocyclic amines described in US Pat. No. 3,188,299, diallyl maleate and other dialkyl esters described in US Pat. No. 4,256,870, olefinic siloxanes described in US Pat. No. 3,989,667, and dialkyl ethynedicarboxylates described in US Pat. No. 4,347,346. Also included are the following classes of inhibitors: hydrazines, triazoles, phosphines, mercaptans, organic nitrogen compounds, acetylenic alcohols, silylated acetylenic alcohols, maleates, fumarates, ethylenically or aromatically unsaturated amides, ethylenically unsaturated isocyanates, olefinic siloxanes, unsaturated hydrocarbon monoesters and diesters, conjugated ene-ynes, hydroperoxides, nitriles and diaziridines.The crosslinking inhibitor D is preferably selected from 1,3,5,7-tetramethyl-1,3,5,7-tetravinyl-cyclotetrasiloxane, 1-ethynyl-1-cyclohexanol (ECH), 3-methyl-1-butyn-3-ol, 2-methyl-3-butyn-2-ol, 3-butyn-1-ol, 3-butyn-2-ol, propargyl alcohol, 2-phenyl-2-propyn-1-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclopentanol, 1-phenyl-2-propynol, 3-methyl-1-penten-4-yn-3-ol, 3-methyl-1-dodecyne-3-ol, 3,7,11-trimethyl-1-dodecyne-3-ol, diphenyl-1,1-propyne-2-ol-1, 3,6-diethyl-1-nonyne-3-ol, 3-methyl-1-pentadecyne-3-ol, and mixtures thereof. Acetylenic alcohols are highly preferred crosslinking inhibitors D according to the invention, and very particularly 1-ethynyl-1-cyclohexanol (ECH). According to one embodiment, the silicone composition X comprises between 2 and 10,000 ppm of crosslinking inhibitor D, preferably between 5 and 1,000 ppm, relative to the total weight of the silicone composition X.

[0063] The crosslinkable silicone composition X may comprise a filler E. According to one embodiment, the silicone composition X comprises between 5% and 40% by weight of filler E relative to the total weight of the silicone composition X. Advantageously, the silicone composition X comprises between 8% and 20% by weight of filler E.

[0064] The filler E that may be provided is preferably mineral. The filler E may be a very finely divided product with an average particle diameter of less than 0.1 μm. The filler E may be siliceous in particular. With regard to siliceous materials, they may act as reinforcing or semi-reinforcing fillers. The reinforcing siliceous fillers are chosen from colloidal silicas, combustion and precipitation silica powders or mixtures thereof. These powders have an average particle size generally less than 0.1 μm (micrometers) and a BET specific surface area greater than 30 m 2 / g, preferably between 30 and 350 m 2 / g. Semi-reinforcing siliceous fillers such as diatomaceous earth or ground quartz can also be used. These silicas can be incorporated as such or after having been treated with organosilicon compounds usually used for this purpose. These compounds include methylpolysiloxanes such as hexamethyldisiloxane, octamethylcyclotetrasiloxane, methylpolysilazanes such as hexamethyldisilazane, hexamethylcyclotrisilazane, tetramethyldivinyldisilazane, chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, dimethylvinylchlorosilane, alkoxysilanes such as dimethyldimethoxysilane, dimethylvinylethoxysilane, trimethylmethoxysilane, and mixtures thereof. As for non-siliceous mineral materials, they can be used as semi-reinforcing or bulking mineral fillers.Examples of these non-siliceous fillers that can be used alone or in mixtures are calcium carbonate, possibly surface-treated with an organic acid or an ester of an organic acid, calcined clay, rutile-type titanium oxide, iron, zinc, chromium, zirconium, magnesium oxides, different forms of alumina (hydrated or not), boron nitride, lithopone, barium metaborate, barium sulfate and glass microbeads. These fillers are coarser, generally with an average particle diameter greater than 0.1 μm and a specific surface area generally less than 30 μm. 2 / g. These charges may have been surface modified by treatment with the various organosilicon compounds usually used for this purpose.

[0065] Preferably, the filler E is silica, and even more preferably combustion silica. Advantageously, the silica has a BET specific surface area of ​​between 75 and 410 m 2 / g.

[0066] Silicone composition X may also include other functional additives that are common in silicone compositions. Examples of common functional additive families include: adhesion promoters, adhesion modulators, silicone resins, additives for increasing consistency, additives for heat resistance, oil resistance or fire resistance, for example metal oxides, virucides, bactericides, anti-abrasion additives, and pigments (organic or mineral).

[0067] According to a preferred embodiment, the silicone composition X according to the invention comprises, based on the total weight of the silicone composition X: - from 50% to 95%, preferably from 60% to 87%, of an organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups linked to silicon, - from 0.1% to 10%, preferably from 0.5% to 5%, of an organopolysiloxane B having, per molecule, at least two SiH units, and - from 1 ppm to 400 ppm, preferably from 2 ppm to 200 ppm, and more preferably from 5 to 100 ppm (calculated in parts per million of metal) of a hydrosilylation catalyst C which is Pt(octane-2,4-dione)2, and - optionally, preferably between 5% and 40%, of a charge E.

[0068] Silicone composition X can be prepared by mixing all of the different components as described above.

[0069] According to one embodiment, the silicone composition X according to the invention can be prepared from a two-component system characterized in that it is presented in two distinct parts intended to be mixed to form said silicone composition X, and in that one of the parts comprises the catalyst C and does not comprise the organopolysiloxane B, while the other part comprises the organopolysiloxane B and does not comprise the catalyst C.

[0070] Alternatively, the silicone composition X according to the invention may be a single-component system.

[0071] The present invention also relates to a premix for a silicone composition comprising: - at least one organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups linked to silicon, and - at least one hydrosilylation catalyst C which is Pt(octane-2,4-dione)2.

[0072] In said premix, the weight quantity of hydrosilylation catalyst C, calculated by weight of platinum metal, is generally between 0.1% and 10%, based on the total weight of the premix.

[0073] The premix may optionally include a co-solvent, for example hexamethyldisiloxane or a short silicone oil, typically having a viscosity of less than 100 mPa.s.

[0074] Process for preparing a coating on a support

[0075] The invention also relates to a method for preparing a coating on a support, comprising the following steps: - application of a silicone composition X to a support, preferably a textile support, and - crosslinking of said composition by electronic or photonic irradiation, preferably by exposure to an electron beam, by exposure to gamma rays, or by exposure to radiation with a wavelength between 100 nm and 450 nm, in particular to UV radiation

[0076] The application of the silicone composition X can be carried out by continuously or discontinuously depositing said silicone composition X on at least one face of said support.

[0077] The deposition can typically be done by transfer, by licking roller or by spraying using a nozzle, a doctor blade, a rotating frame or a reverse roll. The thickness of the layer of silicone composition X deposited on the support can be between 0.1 mm and 0.8 mm, preferably between 0.3 mm and 0.6 mm and even more preferably between 0.4 mm and 0.5 mm.

[0078] According to one embodiment, the crosslinking step of the method according to the invention is carried out by UV radiation with a wavelength between 100 nm and 405 nm. According to a preferred embodiment of the invention, the radiation is ultraviolet light with a wavelength less than or equal to 405 nanometers. According to a preferred embodiment of the invention, the radiation is ultraviolet light with a wavelength greater than 100 nanometers.

[0079] UV radiation can be emitted by doped or undoped mercury vapor lamps with an emission spectrum ranging from 100 nm to 405 nm. Light sources such as light-emitting diodes (LEDs), which deliver point-like UV or visible light, can also be used.

[0080] According to a preferred embodiment, the crosslinking of said silicone composition X is carried out by irradiation with UV radiation, the source of which is a UV-LED lamp. Said UV-LED lamp can emit radiation of wavelength 365 nm, 385 nm, 395 nm or 405 nm. Preferably, the UV-LED lamp is a lamp emitting at 395 nm.

[0081] The power of the UV-LED lamp is preferably between 2 W / m 2 and 200,000 W / m 2 .

[0082] According to a preferred embodiment, the irradiation of the silicone composition X is carried out continuously, by scrolling the support under the UV-LED lamp. The scrolling speed and the number of passes can be defined so that the total irradiation of the silicone composition takes place for a duration of between 1 s and 60 s, more preferably between 2 s and 40 s, and even more preferably between 3 s and 15 s. Thus, the energy received by the silicone composition X by irradiation is preferably between J / m 2 and 1200 J / cm 2 , more preferably between 5 J / m 2 and 5 J / cm 2 .

[0083] According to a preferred embodiment, the crosslinking step is carried out without inerting. However, it is not excluded to proceed under an inert atmosphere, for example under nitrogen, under argon or under oxygen-depleted air.

[0084] The crosslinking step is carried out at a temperature between 15°C and 60°C, more preferably between 20°C and 40°C, and even more preferably at room temperature, typically around 25°C.

[0085] According to the invention, any type of support can be used, in particular textile supports. For information purposes, among the textile supports, we can cite: - natural textiles, such as: textiles of plant origin, such as cotton, linen, hemp, jute, coconut, cellulose fibers from paper; and textiles of animal origin, such as wool, hair, leather and silk; - artificial textiles, such as: cellulosic textiles, such as cellulose or its derivatives; and protein textiles of animal or vegetable origin; and - synthetic textiles, such as polyester, polyamide, polymallic alcohols, polyvinyl chloride, polyacrylonitrile, polyolefins, acrylonitrile, (meth)acrylate-butadiene-styrene copolymers and polyurethane.

[0086] Synthetic textiles obtained by polymerization or polycondensation may in particular include in their matrix different types of additives, such as pigments, delustering agents, matting agents, catalysts, thermal and / or light stabilizers, anti-static agents, flame retardants, anti-bacterial, anti-fungal, and / or anti-mite agents.

[0087] Examples of textile surfaces include surfaces obtained by the rectilinear interlacing of threads or fabrics, surfaces obtained by the curvilinear interlacing of threads or knits, mixtilinear or tulle surfaces, non-woven surfaces and composite surfaces.

[0088] The textile support used in the method of the present invention may consist of one or more textiles, identical or different, assembled in various ways. The textile may be single- or multi-layer. The textile support may, for example, consist of a multi-layer structure that can be produced by different assembly means, such as mechanical means such as sewing, welding, or point or continuous gluing.

[0089] The textile support may, in addition to the coating process according to the present invention, undergo one or more other subsequent treatments, also called finishing or finishing treatments. These other treatments may be carried out before, after and / or during said coating process of the invention. As other treatments subsequent processes include: dyeing, printing, laminating, coating, assembly with other materials or textile surfaces, washing, degreasing, preforming or fixing.

[0090] According to one embodiment, the support is an openwork and / or elastic textile support.

[0091] A textile is said to be "openwork" when it includes free spaces not made of textile. Said free spaces (which may be designated as pores, voids, alveoli, holes, interstices or orifices) may or may not be distributed regularly over the textile. These free spaces may in particular be created during the production of the textile. For the coating of the silicone composition of the invention to be effective, it is preferable that the smallest of the dimensions of these free spaces be less than 5 mm, in particular less than 1 mm.

[0092] A textile is said to be "elastic" when it has an elasticity rate greater than 5%, preferably greater than 15%. The elasticity rate of a textile can typically reach up to 500%. The elasticity rate represents the percentage of elongation of the textile when it is stretched to its maximum. The elongation can be only longitudinal, only transverse, or both longitudinal and transverse.

[0093] The textile support can be lace or an elastic band.

[0094] The present invention also relates to a coated support capable of being obtained according to said method.

[0095] The coated textile supports thus obtained, as such or transformed into textile articles, can be used in numerous applications, such as, for example, in the field of clothing, in particular lingerie such as lace for tops, stockings or bras, and sportswear, and hygiene articles, such as support bands or dressings.

[0096] Other applications

[0097] The present invention also relates to the use of Pt(octane-2,4-dione)2 as a hydrosilylation catalyst.

[0098] The present invention also relates to the use of silicone composition X for the preparation of silicone elastomers.

[0099] The invention also relates to the use of composition X according to the invention in the field of electronics, for example for the preparation of conformal coatings of printed circuits, and for the filling of microcircuits and electronic components such as IGBTs.

[0100] The invention also relates to the use of the composition X according to the invention, for the preparation of silicone elastomer articles by an additive manufacturing process. Additive manufacturing processes are also known as 3D printing processes. This description generally includes the designation ASTM F2792-12a, “Standard Terminology for Additive Manufacturing Technologies”. In accordance with this ASTM standard, a “3D printer” is defined as “a machine used for 3D printing” and “3D printing” is defined as “the fabrication of objects through the deposition of a material using a print head, nozzle or other printer technology”.

[0101] Additive manufacturing “AM” is defined as a process of joining materials to make objects from 3D model data, typically layer upon layer, as opposed to subtractive manufacturing methods. Synonyms associated with 3D printing and encompassed by 3D printing include additive manufacturing, additive processes, additive techniques, and layer fabrication. Additive manufacturing (AM) may also be referred to as rapid prototyping (RP). As used herein, “3D printing” is interchangeable with “additive manufacturing” and vice versa.

[0102] Irradiating the layers of silicone X compositions as they are printed allows for rapid gelation of at least part of the composition during production and thus each layer retains its shape without collapse of the printed structure.

[0103] Advantageously, the silicone compositions X according to the invention can be used for 3D printing processes using vat photopolymerization (Digital Light Processing, stereolithography), material extrusion, material deposition, or inkjet, by adapting the viscosity of the silicone composition X to the technology used.

[0104] Other details or advantages of the invention will appear more clearly from the examples given below for information purposes only. Examples

[0105] The silicone compositions described as examples below were obtained from the following raw materials: A: poly(dimethylsiloxane) with dimethylvinylsilyl ends, viscosity "100 mPa.s, containing approximately 2% by weight of Si-vinyl function B: poly(methylhydrogensiloxane) with trimethylsilyl ends containing 56% by weight of SiH function C1: Pt(octane-2,4-dione)2 prepared according to Example 1 C2: Pt(acac)2 (0.1% solution in dichloromethane) C3: Pt(heptane-3,5-dione)2 prepared according to Example 1 using heptane-3,5-dione C4: Pt(2,4-hexanedione)2 prepared according to Example 1 using 2,4-hexanedione C5: mixture of Pt Karstedt-benzoquinone complexes according to application WO95 / 25734

[0106] Example 1: Synthesis of catalyst C1 Pt(octane-2,4-dione)2. Characterization and toxicity test

[0107] A solution of NaOH (3.0 eq) in distilled water was added to octane-2,4-dione (4.0 eq) and the mixture was stirred at 70 °C for 5 min. K2PtCL (500 mg, 1.20 mmol, 1.0 eq) was then added and the reaction mixture was stirred at 70 °C in the dark. The reaction rapidly changed color from red to orange to yellow and a brown oil separated from the clear aqueous solution. The consumption of octane-2,4-dione was monitored by GC-FID and no further change was observed after 4 h. The mixture was then cooled to 25 °C and diluted with CH2Cl2. The phases were separated and the aqueous phase was extracted again with CH2Cl2. The combined organic phases were dried over Na2SO4, filtered and concentrated under reduced pressure to give a brown oily residue.

[0108] Purification was carried out by flash chromatography on a silica gel column (cyclohexane / EtOAc 75:25). Two fractions were obtained: - cis-Pt(octane-2,4-dione)2 isolated as a yellow solid with a yield of 33% and a purity of 99% (mass % determined by NMR 1 H), cis / trans ratio 91 / 9 (determined by NMR 1 H), - trans-Pt(octane-2,4-dione)2 isolated as a yellow solid with a yield of 28% and a purity of 98% (mass % determined by NMR 1 H), cis / trans ratio 4 / 96 (determined by NMR 1 H).

[0109] Cis-Pt(octane-2,4-dione)2(toluene-d8, 400MHz, 25 °C) 5 = 5.14 (s, 2H), 1.89 (t, J = 7.6Hz, 4H), 1.53 (s, 6H), 1.43 (quint, J = 7.6Hz, 4H), 1.13 (sext, J = 7.2Hz, 4H), 0.75 (t, J = 7.2Hz, 6H)

[0110] Trans-Pt(octane-2,4-dione)2(toluene-d8, 400MHz, 25 °C) 5 = 5.14 (s, 2H), 1.90 (t, J = 7.6Hz, 4H), 1.52 (s, 6H), 1.44 (quint, J = 7.6Hz, 4H), 1.14 (sext, J = 7.6Hz, 4H), 0.75 (t, J = 7.2Hz, 6H)

[0111] Toxicity test (Ames test, according to OECD Guidelines for the Testing of Chemicals - Test No. 471: Bacterial Reverse Mutation Assay): Solutions were prepared with Pt(octane-2,4-dione)2. They did not induce any mutagenic changes in Salmonella typhimurium TA 1535, TA 1537, TA 98, TA 100 and in Escherichia coli WP2(uvrA-) (pKM 101) without or with metabolic activation for 5000, 1500, 500, 150 and 50 pg / plate.

[0112] Example 2: Determination of catalyst activity

[0113] Operating mode: - prepare a stock solution of catalysts C1 or C2 at 600 ppm Pt in hexamethyldisiloxane, - add 0.1 mL of the stock solution to 5.5 g of organopolysiloxane A, then introduce 0.29 g of organopolysiloxane B (SiH / SiVinyl molar ratio = 2:1, and Pt metal content of 10 ppm) - irradiate the solution while stirring (500 rpm) while maintaining a flow of compressed air until the liquid becomes a gel and the mass is no longer agitated.

[0114] Irradiation: UV LED lamp with a wavelength of 365 nm

[0115] The crosslinking time is measured. It corresponds to the time taken for the system to solidify (the magnetic bar can no longer stir the system). The results are presented in Table 1.

[0116] [Table 1] excellent properties. In fact, the crosslinking time under UV is lower than with the reference catalyst Pt(acac)2. In addition, Pt(octane-2,4-dione)2 has better solubility in silicones.

[0118] Example 3: DSC Photo Experiments

[0119] The >90% pure form of the complexes was isolated and evaluated by Photo-DSC (DSC = differential scanning calorimetry) with the same formulation as in Example 2 to determine the time to maximum reaction rate.

[0120] The time to reach maximum heat flux in mW / s and peak values ​​are recorded in the table below.

[0121] Operating mode: - a stock solution of catalyst at 600 ppm of Pt in hexamethyldisiloxane is prepared, - 30 mg of the stock solution is added to 1.76 g of organopolysiloxane A, then 48 mg of organopolysiloxane B is introduced. The samples obtained have a Pt metal content of 10 ppm. Photo-DSC experiments were carried out using a Metier DSC system equipped with a Hamamatsu model LC8-02 UV point light source under N2 purge, - Two waveguides coupled to the instrument transmit equal photo doses to the sample cup and an empty reference cup, while the DSC measures the heat flux, - The light source is a mercury-xenon lamp with a 365 nm filter and the UV dose at 365 nm is 14.4 mW / cm 2 ).

[0122] The results are presented in Table 2.

[0123] [Table 2] ;0124] These results show that both Pt(octane-2,4-dione)2 diastereomers have a higher thermal peak than reference catalysts, such as Pt(acac)2. High peaks are desirable because they correspond to higher activity. Furthermore, the time to reach the thermal peak for both Pt(octane-2,4-dione)2 diastereomers is comparable to or lower than that of the other catalysts tested. This demonstrates good reactivity of Pt(octane-2,4-dione)2.

[0125] These results also show that the two Pt(octane-2,4-dione)2 diastereomers exhibit a solubility in the silicone composition that is comparable or improved compared to that of the other catalysts tested.

[0126] Example 4: Determination of catalyst solubility

[0127] The solubility of the different C1-C5 catalysts was determined in hexamethyldisiloxane (HMDSO) at 20°C according to the following protocol. 1) Take 5 mg of Pt catalyst and add 200 mg of HMDSO, 2) Stir for 5 min at 20 °C to suspend the catalyst and saturate the medium 3) Dilute with HMDSO by successive additions (additions of 100 mg up to a total of 1 g then additions of 500 mg) while maintaining stirring of the medium. Continue the additions until a clear medium is obtained, without observing a precipitate when stirring stops. The results are presented in Table 3.

[0128] [Table 3] [i29] These results show that Pt(octane-2,4-dione)2 (C1) has much better solubility in silicones than other Pt-based complexes, and in particular, other Pt p-diketonates (C3 and C4).

[0130] Example 5: Determination of catalyst stability

[0131] A solution comprising a catalyst C1 or C5, as well as organopolysiloxanes A and B was prepared according to Example 2 (Pt metal content of 10 ppm).

[0132] The stability of the solutions was then determined.

[0133] The solution comprising Pt(octane-2,4-dione)2 (C1) remains stable for more than 20 days protected from light and more than 7 hours exposed to ambient light.

[0134] The solution comprising the mixture of Pt Karstedt-benzoquinone complexes (C5) crosslinks after 5 minutes protected from light.

[0135] These results show that the silicone composition according to the invention has very good stability without irradiation. Indeed, the gel time without irradiation is very long and much greater than that obtained with the mixture of Pt Karstedt-benzoquinone complexes (C5).

Claims

Demands

1. Irradiation crosslinkable silicone composition X comprising: a. at least one organopolysiloxane A having, per molecule, at least two silicon-linked C2-C12 alkenyl groups; b. at least one organopolysiloxane B having, per molecule, at least two SiH motifs; and c. a catalytically effective amount of at least one hydrosilylation catalyst C, which is Pt(octane-2,4-dione)2.

2. Silicone composition X according to claim 1, characterized in that Pt(octane-2,4-dione)2 is a mixture of cis and trans diastereomer

3. Silicone composition X according to any one of the preceding claims, characterized in that it is crosslinkable by exposure to radiation with a wavelength between 100 nm and 450 nm, in particular to UV radiation.

4. Silicone composition X according to any one of the preceding claims, characterized in that the weight quantity of catalyst C, calculated in weight of platinum-metal, is generally between 1 and 400 ppm, preferably between 2 and 200 ppm, and more preferably between 5 and 100 ppm, based on the total weight of silicone composition X.

5. A method for preparing a coating on a substrate, comprising the following steps: - application of a silicone composition X according to any one of claims 1 to 4 onto a substrate, preferably a textile substrate, and - crosslinking of said composition by electron or photonic irradiation, preferably by exposure to an electron beam, by exposure to gamma rays, or by exposure to radiation with a wavelength between 100 nm and 450 nm, in particular to UV radiation.

6. The method according to claim 5, characterized in that the crosslinking takes place by exposure to UV radiation whose source is a UV-LED lamp.

7. Coated support obtainable according to the process according to claim 5 or 6.

8. Use of silicone composition X according to any one of claims 1 to 4, for the preparation of silicone elastomers.

9. Use of Pt(octane-2,4-dione)2 as a hydrosilylation catalyst.

10. Premix for silicone composition comprising: - at least one organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups linked to silicon, and - at least one hydrosilylation catalyst C which is Pt(octane-2,4-dione)2.

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