WO2023111478A1

WO2023111478A1 - Silicone composition which is cross-linkable by irradiation

Info

Publication number: WO2023111478A1
Application number: PCT/FR2022/052391
Authority: WO
Inventors: Perrine Theil; Etienne Fleury; Marc BARON
Original assignee: Elkem Silicones France Sas; Institut National Des Sciences Appliquees De Lyon; Centre National De La Recherche Scientifique; Universite Claude Bernard Lyon 1; Universite Jean Monnet Saint Etienne
Priority date: 2021-12-17
Filing date: 2022-12-16
Publication date: 2023-06-22
Also published as: FR3130816A1; FR3130816B1

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 which is cross-linkable by irradiation, comprising at least one compound D selected from retinol, retinal, retinoic acid, retinol carboxylic acid esters, carotenes, and mixtures thereof.

Description

Silicone composition crosslinkable by irradiation

Technical area

The present invention relates to a crosslinkable silicone composition X by polyaddition reactions to form a silicone elastomer. In particular, the subject of the present invention is a silicone composition X which can be crosslinked by irradiation, and comprising at least one compound D selected from retinol, retinal, retinoic acid, carboxylic acid esters of retinol, carotenes, and their mixtures.

Technology background

[0002] Silicone compositions that can be crosslinked by polyaddition reactions are generally thermally crosslinked in the presence of a platinum catalyst, in particular the Karstedt catalyst. However, for several years, compositions which can be crosslinked by irradiation have been developed. This type of composition which can be crosslinked by irradiation is in particular very useful for “coating” type applications, where a support is covered with a silicone coating. In addition, this type of process has advantages because it consumes less energy than the thermal process, which saves money. This is especially true when the irradiation is carried out by UV-LED systems.

[0003] Patent application WO9525734 describes photoactive organoplatinic complexes for crosslinking by hydrosilylation of organopolysiloxane SiH and SiVi. These photoactive organoplatinic complexes are prepared by reacting a photosensitive ligand with the Karstedt complex. However, the systems described in this application do not make it possible to obtain both good reactivity under UV (rapid crosslinking under irradiation), and good stability of the composition without irradiation (long gel time without irradiation).

Document EP0398701 describes silicone compositions comprising a compound having aliphatic unsaturation, a compound containing at least one hydrogen atom bonded to silicon, and a platinum(II) catalyst having p-diketonate ligands, such as Pt (acetylacetonate)2. These compositions are crosslinkable by actinic irradiation. However, these catalysts may exhibit low activity due to limited solubility in silicones.

[0005] It is also known to use the MesPt(MeCp) complex (platinum trimethyl(methylcyclopentadienyl) complex) as a photocatalyst for hydrosilylation reactions. However, the use of this catalyst has drawbacks because it is volatile, expensive and very toxic. Furthermore, the systems described above are not necessarily usable when the irradiation is carried out by LIV-LED systems. Indeed, working with a 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 reactivity of the system.

[0007] It is therefore necessary to develop photocatalytic systems that can overcome these disadvantages.

In this context, the present invention aims to satisfy at least one of the following objectives. One of the objectives of the invention is to provide a composition that can be crosslinked under UV irradiation, and in particular UV-LED.

Another object of the invention is to provide a composition that can be crosslinked under irradiation with good reactivity.

Another object of the invention is to provide a composition that can be crosslinked under irradiation with good stability when it is not irradiated (long gel time without irradiation).

Brief description of the invention

[0011] These objectives, among others, are achieved by the present invention which firstly relates to a radiation-crosslinkable silicone X composition 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; vs. a catalytically effective amount of at least one hydrosilylation catalyst C, preferably a platinum-based hydrosilylation catalyst; and D. at least one compound D selected from retinol, retinal, retinoic acid, retinol carboxylic acid esters, carotenes, and mixtures thereof.

[0012] The fact of using a compound D as defined 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 rapidly. In addition, compound D makes it possible to stabilize the silicone composition X before irradiation. Thus, it is possible to keep the silicone composition X uncrosslinked for several hours, when the composition is not subjected to irradiation. In addition, compound D can be chosen from natural products, which is advantageous. The present invention also relates to a process for preparing a coating on a support, comprising the following steps:

- application of a silicone composition X on a support, preferably a textile support, and

- crosslinking of said composition by electron or photon irradiation, preferably by exposure to an electron beam, by exposure to gamma rays, or by exposure to radiation with a wavelength of between 100 nm and 450 nm, in particular at LIV radiation.

The present invention also relates to a coated support obtainable by said method.

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

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 bonded to silicon,

- at least one hydrosilylation catalyst C, and

- at least one compound D selected from retinol, retinal, retinoic acid, retinol carboxylic acid esters, carotenes, and mixtures thereof.

Definitions

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

[0018] In the present text, “UV” means ultraviolet. Ultraviolet radiation is defined as electromagnetic radiation whose wavelength is between about 100 nm and about 405 nm, i.e. below the visible light spectrum.

[0019] In addition, in the present text, “LED” is the well-known abbreviation to those skilled in the art for “electroluminescent diode” (also DEL in French). [0020] Unless otherwise indicated, all the viscosities of the silicone oils referred to in this presentation correspond to a dynamic viscosity magnitude at 25° C. called "Newtonian", that is to say the dynamic viscosity which is measured , in a manner known per se, with a Brookfield viscometer at a sufficiently low shear rate gradient for the measured viscosity to be independent of the rate gradient.

In the present description, the term "textile" is a generic term encompassing all textile structures. Textiles can be made of yarns, fibers, filaments and/or other materials. They include in particular flexible fabrics, whether woven, glued, knitted, braided, felt, needled, sewn, or made by another method of manufacture. By “yarn”, we mean for example a continuous multifilament object, a continuous yarn obtained by assembling several yarns or a continuous yarn of fibers, 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 nonwoven articles or a tow intended to be cut to form short fibers. The textile may well consist of yarns, fibers and/or filaments which have undergone one or more treatment steps before the production of the textile surface, such as, for example, steps of texturing, drawing, drawing-texturing, sizing, relaxation, heat setting, twisting, setting, crimping, washing and/or dyeing.

[0022] In the present application, all % and ppm are given by weight, unless otherwise stated.

detailed description

[0023] Cross-linkable X-silicone composition

The subject of the present invention is a silicone composition X that can be crosslinked by irradiation, 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; vs. a catalytically effective amount of at least one hydrosilylation catalyst C; and D. at least one compound D selected from retinol, retinal, retinoic acid, retinol carboxylic acid esters, carotenes, and mixtures thereof. The organopolysiloxane A having, per molecule, at least two C2-C12 alkenyl groups bonded to silicon, may in particular comprise:

- 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 ¹ is a monovalent hydrocarbon group having from 1 to 12 carbon atoms, preferably chosen from alkyl groups having from 1 to 8 carbon atoms such as methyl, ethyl, propyl groups, optionally substituted by at least one atom of halogen such as chlorine or fluorine, cycloalkyl groups having 3 to 8 carbon atoms and aryl groups having 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

- optionally other units 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.

It is understood in the formulas above that, if several R ¹ groups are present, they may be identical to or different from each other.

These organopolysiloxanes A may have a linear structure, essentially consisting of "D" siloxyl units 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 siloxyl units YR ¹ 2SiOi/2, Y2R ¹ SiOi/2 and R ¹ ₃ SiOi/2. The symbols Y and R ¹ are as described above.

As examples of terminal “M” units, mention may be made of the trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy or dimethylhexenylsiloxy groups.

As examples of “D” units, mention may be made of dimethylsiloxy, methylphenylsiloxy, diphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyldecenylsiloxy or methyldecadienylsiloxy groups.

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 trimethyl-silyl ends; And

- a cyclic poly(methylvinylsiloxane).

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

Optionally, the organopolysiloxanes A may also contain “T” siloxyl units (R ¹ SiC>3/2) and/or “Q” siloxyl units (SiC/2). The symbols R ¹ are as described above. The organopolysiloxanes A then have a branched structure. Examples of branched organopolysiloxanes which can 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.

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

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%.

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.

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.

The organopolysiloxane B is an organohydrogenpolysiloxane compound comprising per molecule at least two, and preferably at least three, hydrogenosilyl functions or Si—H units.

The organohydrogenpolysiloxane B can 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 ² radicals, which are 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 optionally other units of the following formula: R ² fSiO<4-f)/2 in which R ² has the same meaning as above, and f = 0, 1, 2, or 3.

It is understood in the formulas above that, if several R ² groups are present, they may be identical to or different from each other. Preferably, R ² can represent a monovalent radical chosen 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 with 8 carbon atoms and aryl groups having 6 to 12 carbon atoms. R ² can advantageously be chosen from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl.

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

The organohydrogenpolysiloxane B can 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.

When it comes to linear polymers, these essentially consist 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 aSiOi/2 or M': R ² 2HSiOi/2 where R ² has the same meaning as above.

Examples of organohydrogenpolysiloxanes which may be organopolysiloxanes B according to the invention comprising at least two hydrogen atoms bonded to a silicon atom are:

- a poly(dimethylsiloxane) with hydrogendimethylsilyl ends;

- a poly(dimethylsiloxane-co-methylhydrogenosiloxane) with trimethyl-silyl ends;

- a poly(dimethylsiloxane-co-methylhydrogenosiloxane) with hydrogendimethylsilyl ends;

- a poly(methylhydrogenosiloxane) with trimethylsilyl ends; And

- a cyclic poly(methylhydrogensiloxane).

When the organohydrogenpolysiloxane B has a branched structure, it is preferably chosen from the group consisting of silicone resins of the following formulas:

- M'Q where the hydrogen atoms bonded to silicon atoms are carried by the M groups, - MM'Q where the hydrogen atoms bonded to silicon atoms are carried by part of the M units,

- MD'Q where the hydrogen atoms bonded to silicon atoms are carried by the D groups,

- MDD’Q where the hydrogen atoms bonded to silicon atoms are carried by part of the D groups,

- MM'TQ where the hydrogen atoms bonded to silicon atoms are carried by part of the M units,

- MM'DD'Q where the hydrogen atoms bonded to silicon atoms are carried by part of the M and D patterns,

- and mixtures thereof, with M, M', D and D' as defined above, T: siloxyl unit of formula R ² aSiOi/2 and Q: siloxyl unit of formula SiC /2, where R ² has the same meaning as above.

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%.

Considering the whole of the silicone composition X, the molar ratio of the hydrogenosilyl Si-H functions 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.

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.

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.

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.

According to one embodiment, the silicone composition X may comprise a mixture:

- at least one organohydrogenpolysiloxane B as described above comprising two SiH functions per molecule; And

- at least one organohydrogenpolysiloxane B as described above comprising at least three SiH functions per molecule. Catalyst C is a hydrosilylation reaction catalyst. Hydrosilylation reaction catalysts are well known. Preferably, platinum and rhodium compounds are used. It is possible, in particular, to use the complexes of platinum and of an organic product described in patents US-A-3,159,601, US-A-3,159,602, US-A-3,220,972 and European patents EP-A- 0.057.459, EP A 0.188.978 and EP-A-0.190.530, the complexes of platinum and of vinylated organosiloxanes described in the patents US-A-3419593, US-A-3 715 334, US-A-3 377,432 and US-A-3,814,730. The generally preferred catalyst is platinum. In this case, the quantity by weight of catalyst C, calculated by 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. In this case, the catalyst C can be a platinum catalyst, for example a Karstedt catalyst (Pt2[(Me2SiCH=CH2)2O]s).

Compound D is selected from retinol, retinal, retinoic acid, retinol carboxylic acid esters, carotenes, and mixtures thereof.

Among the carboxylic acid esters of retinol, mention may be made of C 1 to C acid esters, preferably C 1 to C 6 acid esters, in particular formates, acetates and propionates. The C1-C6 group can be a linear or branched alkyl group.

According to one embodiment, compound D is selected from carotenes. Carotenes are unsaturated compounds generally having 40 carbon atoms. Examples of carotenes include the following carotenes: α-carotene, 0-carotene, γ-carotene, 5-carotene, β-carotene, ζ-carotene and lycopene.

Advantageously, compound D is of formula (I)

in which R is selected from -CH2OH, -CHO, -COOH, -OCOR', and the following groups:

with R′ corresponding to a Ci to Cis alkyl group, preferably Ci to Ce, and more preferably R′ is a methyl.

Preferably, R is the following group

in this case, compound D is β-carotene.

The silicone composition X may comprise a compound D or a mixture of several compounds D.

Certain compounds D are well known for being natural pigments, for example β-carotene. Due to the use of these compounds D, the silicone composition X may optionally be colored. However, it was found that the silicone elastomer obtained after crosslinking of silicone composition X was colorless. The use of compounds D according to the invention is therefore not an obstacle to the preparation of coatings or articles in transparent silicone elastomers.

The molar ratio between the platinum contained in the catalyst C (platinum-metal) and the compound D is between 1:1 and 1:250, preferably between 1:5 and 1:200, and more preferably between 1 :10 to 1:100. According to a particular embodiment, the molar ratio between the platinum contained in catalyst C and compound D is 1:25.

The crosslinkable silicone composition X may comprise between 2 and 10000 ppm of compound D, preferably between 5 and 1000 ppm, relative to the total weight of the silicone composition X.

Advantageously, the silicone composition X according to the invention contains a crosslinking inhibitor E. Crosslinking inhibitors are designed to slow down the crosslinking reaction and are also called retarders. Crosslinking inhibitors are well known in the prior art. Mention may be made, for example, of the cyclic polymethylvinylsiloxanes and the acetylenic alcohols described in US Pat. No. 3,923,705, the acetylenic alcohols described in US Pat. No. 3,445,420, the heterocyclic amines described in US Pat. US Patent 4,256,870, the olefinic siloxanes described in US Patent 3,989,667, and the dialkyl ethynedicarboxylates described in US Patent 4,347,346. Mention may also be made of the following classes of inhibitors: hydrazines, triazoles, phosphines, mercaptans, nitrogenous organic compounds, acetylenic alcohols, silylated acetylenic alcohols, maleates, fumarates, unsaturated ethylenic or aromatic amides, unsaturated ethylenic isocyanates, olefinic siloxanes, unsaturated hydrocarbon monoesters and diesters, conjugated ene-ynes , THE hydroperoxides, nitriles and diaziridines. The crosslinking inhibitor E is preferably chosen 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 E crosslinking inhibitors according to the invention, and most particularly 1-ethynyl-1-cyclohexanol (ECH). According to one embodiment, the silicone composition X comprises between 1 and 1000 ppm of crosslinking inhibitor E, preferably between 2 and 50 ppm, relative to the total weight of the silicone composition X.

The crosslinkable silicone composition X may comprise a filler F. According to one embodiment, the silicone composition X comprises between 5 and 20% by weight of filler F relative to the total weight of the silicone composition X. Advantageously, the composition silicone X comprises between 8 and 15% by weight of filler F.

The optionally provided filler F is preferably mineral. The filler F can be a very finely divided product whose mean particle diameter is less than 0.1 μm. The filler F may in particular be siliceous. As regards siliceous materials, they can play the role of reinforcing or semi-reinforcing filler. 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 greater than 30 m ² /g, preferably between 30 and 350 m ² /g. Semi-reinforcing siliceous fillers such as diatomaceous earth or crushed 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. Among these compounds are methylpolysiloxanes such as hexamethyldisiloxane, octamethylcyclotetrasiloxane, methylpolysilazanes such as hexamethyldisilazane, hexamethylcyclotrisilazane, tetramethyldivinyldisilazane, chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, dimethylvinylchlorosilane ilane, alkoxysilanes such as dimethyldimethoxysilane, dimethylvinylethoxysilane, trimethylmethoxysilane, and mixtures thereof. As regards the non-siliceous mineral materials, they can act as a semi-reinforcing or filling mineral filler. Examples of these non-siliceous fillers which can be used alone or as a mixture are calcium carbonate, optionally treated in surface with an organic acid or with an ester of an organic acid, calcined clay, titanium oxide of the rutile type, oxides of iron, zinc, chromium, zirconium, magnesium, the various forms of alumina (hydrated or not), boron nitride, lithopone, barium metaborate, barium sulphate and glass microbeads. These fillers are coarser with generally an average particle diameter greater than 0.1 μm and a specific surface generally less than 30 m ² /g. These fillers may have been surface-modified by treatment with the various organosilicon compounds usually employed for this purpose.

Preferably, the filler F is silica, and even more preferably combustion silica. Advantageously, the silica has a BET specific surface of between 75 and 410 m ² /g.

According to one particular embodiment, the silicone composition X may comprise a photoinitiator.

The silicone composition X can also comprise other functional additives that are usual in silicone compositions. As families of usual functional additives, mention may be made of: 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).

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 bonded 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,

- from 1 ppm to 400 ppm, preferably from 2 ppm to 200 ppm, and more preferably from 5 to 100 ppm, of a hydrosilylation catalyst C (calculated by weight of metal),

- from 2 to 10,000 ppm, preferably from 5 and 1,000 ppm, of a compound D selected from retinol, retinal, retinoic acid, carboxylic acid esters of retinol, carotenes, and mixtures thereof, and

- optionally, from 1 to 1000 ppm, preferably from 2 and 50 ppm, of a crosslinking inhibitor E.

The silicone composition X can be prepared by mixing all of the different components as described above. According to one embodiment, the silicone composition X according to the invention can be prepared from a two-component system characterized in that it comes in two separate 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.

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

- at least one hydrosilylation catalyst C, and

[0072] Process for preparing a coating on a support

The invention also relates to a method for preparing a coating on a support, comprising the following steps:

- crosslinking of said composition by electron or photon irradiation, preferably by exposure to an electron beam, by exposure to gamma rays, or by exposure to radiation with a wavelength of between 100 nm and 450 nm, in particular at LIV radiation

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

The deposition can typically be done by transfer, by lick roller or by spraying using a nozzle, a doctor blade, a rotating frame or a reverse roller (or "reverse roll" according to Anglo-Saxon terminology). The thickness of the layer of silicone composition X deposited on the support may 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 0.5mm.

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

LIV radiation can be emitted by doped or undoped mercury vapor lamps whose emission spectrum extends from 100 nm to 405 nm. Light sources such as light-emitting diodes, better known by the acronym “LED” (Light-Emitting Diodes) which deliver point UV or visible light can also be used.

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.

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

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 running speed and the number of passages can be defined so that the total irradiation of the silicone composition takes place for a period of between 1 s and 60 s, more preferably between 2 s and 40 s, and so even more preferred between 3 s and 15 s. Thus, the energy received by the silicone composition X by irradiation is preferably between 1 J/m ² and 1200 J/cm ² , more preferably between 5 J/m ² and 5 J/cm ² .

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

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, i.e. typically about 25°C.

According to the invention, any type of support can be used, in particular textile supports. As an indication, among the textile supports, we can mention:

- natural textiles, such as: textiles of plant origin, such as cotton, linen, hemp, jute, coconut, cellulosic fibers from paper; and textiles of animal origin, such as wool, hair, leather and silks;

- artificial textiles, such as: cellulosic textiles, such as cellulose or its derivatives; and proteinaceous textiles of animal or plant origin; And

- synthetic textiles, such as polyester, polyamide, polymallic alcohols, polyvinyl chloride, polyacrylonitrile, polyolefins, acrylonitrile, (meth)acrylate-butadiene-styrene copolymers and polyurethane.

The synthetic textiles obtained by polymerization or polycondensation may in particular comprise in their matrix different types of additives, such as pigments, delustrants, mattifiers, catalysts, heat and/or light stabilizers, anti-static agents , flame retardants, anti-bacterial, anti-fungal, and/or anti-mite agents.

As type of textile surfaces, mention may be made in particular of surfaces obtained by rectilinear interlacing of yarns or fabrics, surfaces obtained by curvilinear interlacing of yarns or knits, mixed or tulle surfaces, nonwoven surfaces and composite surfaces.

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 can be mono- or multi-layer(s). The textile support can for example consist of a multilayer structure that can be produced by different assembly means, such as mechanical means such as sewing, welding, or point or continuous bonding.

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

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

A textile is said to be "openwork" when it includes free spaces not made up of textile. Said free spaces (which may be designated as pores, voids, cells, holes, interstices or orifices) may be evenly distributed or not on the textile. These free spaces can be created in particular during the development of the textile. For the coating of the silicone composition of the invention to be effective, it is preferable for the smallest of the dimensions of these free spaces to be less than 5 mm, in particular less than 1 mm.

[0090] A textile is said to be “elastic” when it has a degree of elasticity greater than 5%, preferably greater than 15%. The elasticity rate of a textile can go up to typically 500%. The elasticity rate represents the percentage of elongation of the textile when it is stretched to the maximum. The elongation can be only longitudinal, only transverse, or longitudinal and transverse.

[0091] The textile support can be lace or an elastic band.

The coated textile supports thus obtained, as such or transformed into textile articles, can be used in many applications, such as, for example, in the field of clothing, in particular lingerie such as lace for tops of stockings. or bras, and sportswear, and hygiene items, such as compression bandages or bandages

[0094] Other applications

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 (“conformal coatings” according to the Anglo-Saxon terminology) of printed circuits. , and for the filling (“potting” according to the Anglo-Saxon terminology) of microcircuits and electronic components such as IGBTs.

The invention also relates to the use of composition X according to the invention, for the preparation of articles in silicone elastomer by an additive manufacturing process. Additive manufacturing processes are also known as 3D printing processes. This description typically 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 manufacture of objects through the deposition of a material at the using a printhead, nozzle or other printer technology”.

[0098] Additive manufacturing “AM” is defined as a process of joining materials to manufacture objects from 3D model data, usually 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 manufacturing. Additive manufacturing (AM) can also be called rapid prototyping (RP). As used herein, "3D printing" is interchangeable with "additive manufacturing" and vice versa.

The irradiation of the layers of silicone compositions X as the printing progresses allows the rapid gelation of at least part of the composition during production and thus each layer retains its shape without the printed structure collapsing. .

[0100] Advantageously, the silicone compositions X according to the invention can be used for 3D printing processes implementing in-vessel photopolymerization (Digital Light Processing, stereolithography), material extrusion, material deposition, or inkjet, by adapting the viscosity of the silicone composition X to the technology used.

[0101] Other details or advantages of the invention will appear more clearly in view of the examples given below for information purposes only.

Examples

The silicone compositions described in the example below were obtained from the following raw materials:

A: poly(dimethylsiloxane) with dimethylvinylsilyl ends, viscosity » WO mPa.s, containing about 2% by weight of Si-vinyl function

B: poly(methylhydrogenosiloxane) with trimethylsilyl ends containing 56% by weight of SiH function

C1: Karstedt platinum catalyst, containing 10% by weight of platinum metal

C2: Pt(acac)2 (0.1% solution in dichloromethane)

C3: MyPt(MeCp)

D1: p-carotene marketed by Sigma-Aldrich

E1: 1-ethynyl-1-cyclohexanol (ECH)

[0103] Operating mode

The various compounds were mixed in a glass bottle equipped with a magnetic stirrer. The amounts of organopolysiloxanes A and B were adjusted so that the SiH/SiVinyl molar ratio = 1.1.

The gel time is measured without irradiation. It corresponds to the setting time of the system (the bar magnet can no longer agitate the system).

For the tests under irradiation, a formulation sample in the form of a thin film is placed under the UV lamp. The freezing time corresponds to the solidification time of the sample. Irradiation: UV LED lamp marketed by the company UWAVE with a wavelength of 395 nm, a power of 12 W/cm ² , and an irradiation source-sample distance of 4 cm

[0107] Example 1 [0108] A silicone composition according to the invention comprising a compound D was tested, under UV irradiation or not, and compared with commercial catalytic systems, some of which are known to be active under UV. The results are shown in Table 1.

[0109] [Table 1]

These results show that the silicone composition according to the invention has excellent properties (test 1). Indeed, the gel time under UV is very low, which means that crosslinking is very fast. In addition, the silicone composition according to the invention is very stable, since the gel time without irradiation is relatively high.

[01111 Example 2 [0112] The impact of the amount of compound D in compositions not comprising a crosslinking inhibitor was evaluated. The catalyst used is catalyst C1 (5 ppm of Pt). The results are shown in Table 2.

[0113] [Table 2]

These results show that the gel time under LIV remains very low, regardless of the amount of compound D, and that the addition of compound D makes it possible to increase the gel time without irradiation, and therefore to improve the stability of the composition.

[0115] Example 3 [0116] The impact of the amount of compound D in compositions comprising a crosslinking inhibitor was also evaluated. The catalyst used is catalyst C1 (5 ppm of Pt). The results are shown in Table 3.

[0117] [Table 3]

These results show that the addition of compound D in a composition comprising a crosslinking inhibitor E makes it possible to reduce the gel time under UV, and to increase the gel time without irradiation in order to reach a threshold completely fact acceptable. [0119] Example 4

[0120] Tests under scrolling were also carried out. A ULINE™ lamp (from UWAVE) mounted on a coating bench was used with the following parameters: Wavelength = 395 nm

Scroll speed = 2 m.min' ¹

Power = 12 W/cm ²

Irradiation source-sample distance = 2 cm

A composition similar to that of test 9, but with 15 ppm of Pt, was tested. It was possible to crosslink this composition after a single pass.

Claims

[Claim 1] Radiation-curable silicone X composition 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; vs. a catalytically effective amount of at least one hydrosilylation catalyst C, preferably a platinum catalyst; and D. at least one compound D selected from retinol, retinal, retinoic acid, retinol carboxylic acid esters, carotenes, and mixtures thereof.

[Claim 2] Silicone composition X according to claim 1, characterized in that compound D is of formula (I)

with R′ corresponding to a C1 to C′ alkyl group, preferably C1 to C6 alkyl group, and more preferably R′ is a methyl.

[Claim 3] Silicone composition X according to claim 1 or 2, characterized in that compound D is β-carotene.

[Claim 4] Silicone composition X according to one of the preceding claims, characterized in that the molar ratio between the platinum contained in the catalyst C and the compound D is between 1:1 and 1:250, preferably between 1: 5 and 1:200, and more preferably between 1:10 and 1:100.

[Claim 5] Silicone composition X according to one of the preceding claims, characterized in that it comprises 2 and 10,000 ppm of compound D, preferably between 5 and 1,000 ppm, relative to the total weight of the silicone composition X.

[Claim 6] Silicone composition X according to one of the preceding claims, characterized in that it is crosslinkable by exposure to radiation with a wavelength of between 100 nm and 450 nm, in particular to LIV radiation.

[Claim 7] Silicone composition X according to one of the preceding claims, characterized in that it additionally comprises between 1 and 1000 ppm of a crosslinking inhibitor E, preferably between 2 and 50 ppm, relative to the total weight of the silicone composition X.

[Claim 8] Process for preparing a coating on a support, comprising the following steps:

- application of a silicone composition X according to any one of claims 1 to 7 on a support, preferably a textile support, and

[Claim 9] Process according to Claim 8, characterized in that the crosslinking takes place by exposure to LIV radiation, the source of which is a LIV-LED lamp.

[Claim 10] Coated support obtainable by the process according to claim 8 or 9.

[Claim 11] Use of the silicone composition X according to any one of Claims 1 to 7, for the preparation of silicone elastomers.

[Claim 12] Premix for a silicone composition comprising:

- at least one hydrosilylation catalyst C, and