Ecological and durable silicone composition for textile coating

Abstract

The present invention relates to a silicone composition crosslinkable by polyaddition reactions intended for coating a substrate, in particular a textile substrate. The silicone composition comprises at least one silicone base capable of crosslinking by polyaddition and an adhesion promoter system, said adhesion promoter system comprising at least one organopolysiloxane compound having at least 2 epoxy groups and at least 3 hydrogenosilyl groups, and at least one compound chosen from organic zinc compounds and organic iron compounds.

Description

[0001] DESCRIPTION

[0002] TITLE: Eco-friendly and sustainable silicone composition for textile coating

[0003] technical field

[0004] The present invention relates to a silicone composition that can be crosslinked by polyaddition reactions for coating substrates, particularly textile substrates. The invention is primarily relevant to the field of airbag manufacturing, but does not exclude other applications such as the manufacture of tent fabrics, parachute fabrics, and the like. These fabrics can be used for textile architectural elements or upholstery fabrics, the manufacture of artificial leather, and, more generally, any heat-resistant technical textile.

[0005] Prior art

[0006] Most modern motor vehicles are equipped with personal protective equipment for vehicle occupants, or "airbags" (see, for example, US patent 5,193,847 for more details on airbag technologies). It is known to use silicone compounds to coat the textile components of airbags. After curing, the silicone elastomer coating provides the textile backing with good thermal and mechanical resistance to the airbag, as well as good durability. The performance of the silicone coating is guaranteed only if the adhesion between the textile backing and the elastomer coating is excellent. This adhesion must be maintained over time, even under conditions of high temperature and humidity.However, the fabric typically used for airbag manufacturing is considered a difficult substrate: it is typically PET fabric obtained directly after weaving, also known as "loom-on-loom," "raw," or "loomstate," which has not undergone any washing or scouring stage after weaving, nor any heat treatment or heat setting stage. These fabrics may have oils or sizing, gluing, and lubricating agents on their surface, which can reduce the adhesion performance of the silicone coating to the fabric.

[0007] There is therefore a continuous need to improve the adhesion of silicone elastomer on all types of textile substrates, particularly on textile substrates which have not undergone a washing or heat-setting stage after weaving.

[0008] Numerous prior art documents have proposed solutions to improve the adhesion of silicone coating to textile substrates.

[0009] In US patent 5,789,084, Dow Corning Toray Silicone proposed in 1998 the use of an organosilicon compound containing epoxy groups and an organic titanium compound as an adhesion promoter. More recently, in US patent applications 2022 / 0282120 and WO 2023 / 091347, the described adhesion promoter consists of a mixture of an alkoxysilane with epoxy groups, a linear organopolysiloxane oligomer with alkenyl and hydroxy or alkoxy groups, and an organic aluminum or zirconium compound as a polycondensation catalyst.

[0010] Shin-Etsu Chemicals proposed in patent application EP 3 653 671 A1 the use of a silicone composition comprising, in particular, an adhesion promoter consisting of a mixture of an organohydrogenopolysiloxane, an isocyanurate compound having an alkoxysilyl functional group, a silicone compound having an epoxy group and an alkoxysilyl group, and a polycondensation catalyst selected from organic titanium compounds and organic zirconium compounds. Patent application WO 2020 / 184193 describes a silicone composition comprising, in particular, an organohydrogenopolysiloxane compound having epoxy groups. It is further described that this compound can be used in combination with other adhesion promoters to improve the bond strength between the crosslinked silicone elastomer and the textile substrate.Examples of adhesion promoters include alkoxysilane compounds containing epoxy, acryloxy, or methacryloxy groups; organopolysiloxane compounds containing epoxy groups; and organopolysiloxane compounds containing, within the same molecule, an epoxy group, an alkenyl group, and an alkoxy group. Titanium and zirconium compounds are also described as acting as condensation agents to promote adhesion.

[0011] In US patent 10,676,574 B2, the Applicant Company proposes a technical solution consisting of a silicone composition comprising a silicone base capable of crosslinking or hardening by polyaddition and an innovative adhesion promoter system comprising an organic titanium compound and a specific linear organopolysiloxane compound bearing epoxy-functional groups and hydrogenosiloxyl groups.

[0012] These adhesion systems have enabled very good performance in terms of abrasion and wrinkling resistance of the textile substrate coated with silicone elastomer, particularly after the coated fabric has aged. However, new expectations have emerged.

[0013] First, it's important to know that titanium is listed as a critical and strategic raw material by the European Union, highlighting the supply and environmental challenges surrounding this resource. It is crucial to find a solution to the depletion of mineral and mining resources. Therefore, technical solutions involving titanium compounds must be re-evaluated.

[0014] One of the objectives of the present invention is therefore to provide a silicone composition for coating substrates, particularly textile substrates, and more specifically for the manufacture of airbags, which eliminates the need for titanium compounds while maintaining good adhesion to the substrate. Such a silicone composition is thus more durable and more environmentally friendly. Furthermore, current industry standards restrict the use of coatings with high VOC (volatile organic compound) emissions. Most existing coating products cannot meet this industry standard. Moreover, for reasons of hygiene and workplace quality, odorless silicone compositions are desired.

[0015] Another objective of the present invention is to provide a silicone composition for coating supports, particularly textile supports, and more specifically for the manufacture of airbags, which reduces the release of volatile compounds and reduces odors associated with these released volatile compounds, while maintaining good adhesion to the substrate and therefore good mechanical properties.

[0016] Summary of the invention

[0017] The present invention relates to a silicone composition comprising at least one silicone base capable of crosslinking by polyaddition and an adhesion-promoting system, said adhesion-promoting system comprising:

[0018] - at least one organopolysiloxane compound A having at least 2 epoxy groups and at least 3 hydrogenosilyl groups, and

[0019] - at least one compound B chosen from among the organic compounds of zinc and the organic compounds of iron.

[0020] Furthermore, the present invention relates to a method for preparing an article comprising a layer of silicone elastomer on a textile support, comprising the following steps: a) preparing a silicone composition as described above; b) depositing said silicone composition on said textile support; c) crosslinking said silicone composition to obtain the silicone elastomer on the textile support.

[0021] Articles that can be obtained by such a process, and in particular airbags obtained in this way, are also objects of the present invention.

[0022] Detailed description of the invention

[0023] Unless otherwise indicated, all the viscosities of silicone oils discussed in this presentation correspond to a dynamic viscosity quantity at 25°C known as "Newtonian", that is to say, the dynamic viscosity which is measured, in a manner known in itself, with a Brookfield viscometer at a shear rate gradient low enough that the measured viscosity is independent of the rate gradient.

[0024] The present invention therefore relates to a silicone composition comprising at least one silicone base capable of crosslinking by polyaddition and an adhesion-promoting system. The adhesion-promoting system developed by the Applicant Company comprises a mixture of at least two compounds: on the one hand, at least one organopolysiloxane compound having at least two epoxy groups and at least three hydrogenosilyl A groups, and on the other hand, at least one compound B selected from organic zinc compounds and organic iron compounds.

[0025] Compound A according to the invention may be a linear, cyclic or branched organopolysiloxane, comprising siloxyl motifs (1.1) and (1.2) of the following formulas:

[0026] Y a ZbSiO(4-ab) / 2 (LI)

[0027] H c Z d SiO(4- c -d) / 2 (L2) and optionally siloxyl motifs (1.3), (1.4), (1.5) and / or (1.6) of the following formulas:

[0028] Z3S1O1 / 2 (1.3)

[0029] Z2S1O2 / 2 (L4)

[0030] ZSiO3 / 2 (L5)

[0031] S1O4 / 2 (1.6) in which: a=l, 2 or 3 and b=0, 1 or 2, with (a+b)=l, 2 or 3, c=l and d=0, 1 or 2, with (c+d)=l, 2 or 3, the symbol Y represents a radical comprising a hydrocarbon group having from 2 to 20 carbon atoms and an epoxy function, possibly with one or more heteroatoms such as an oxygen atom; preferably the symbol Y is a radical chosen from the group consisting of: alkylglycidyl ether, linear, branched or cyclic epoxyalkyl, linear, branched or cyclic epoxyalkenyl and glycidyl ester of carboxylic acid, the symbol Z represents a monovalent hydrocarbon group having from 1 to 30 carbon atoms, possibly substituted, preferably chosen from the group consisting of: alkyl groups having from 1 to 8 carbon atoms and aryl groups having from 6 to 12 carbon atoms;and more preferably chosen from the group consisting of: methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl, with the condition that compound A comprises, per molecule, at least 2 siloxyl motifs (1.1) and at least 3 siloxyl motifs (1.2).

[0032] It is understood in all the formulas described here that, if several groups Y or Z are present, they may be identical or different from each other.

[0033] Compound A may typically have a total number of siloxyl motifs less than or equal to 30, preferably between 4 and 25.

[0034] According to one embodiment, compound A according to the invention can be a linear or cyclic organopolysiloxane, comprising siloxyl motifs (1.1) and (1.2), optionally siloxyl motifs (1.3) and (1.4), but not comprising (or substantially not comprising) siloxyl motifs (1.5) and (1.6).

[0035] According to a particularly preferred embodiment, compound A is a linear organopolysiloxane comprising siloxyl motifs (1.1) to (1.3) of the following formulas: Y a ZbSiO(4-ab) / 2 (II)

[0036] H c Z d SiO(4- c -d) / 2 (1.2)

[0037] Z3S1O1 / 2 (1.3) in which: a=l and b=l or 2 c=l and d=l or 2 and not comprising siloxyl motifs (1.4) to (1.6) of the following formulas:

[0038] Z2S1O2 / 2 (1.4)

[0039] ZSiO3 / 2 (1.5)

[0040] S1O4 / 2 (1.6) the symbol Y representing a radical comprising a hydrocarbon group having from 2 to 20 carbon atoms and an epoxy function, optionally with one or more heteroatoms such as an oxygen atom; preferably the symbol Y is a radical selected from the group consisting of: alkylglycidyl ether, linear, branched or cyclic epoxyalkyl, linear, branched or cyclic epoxyalkenyl and glycidyl ester of carboxylic acid, the symbol Z representing a monovalent hydrocarbon group having from 1 to 30 carbon atoms, optionally substituted, preferably selected from the group consisting of: alkyl groups having from 1 to 8 carbon atoms and aryl groups having from 6 to 12 carbon atoms; and more preferably chosen from the group consisting of: methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl, with the condition that compound A comprises, per molecule, at least 2 siloxyl motifs (1.1) bearing epoxyfunctional hydrocarbon groups and at least 3 siloxyl motifs (1.2) bearing hydrogenosiloxyl groups.

[0041] This particularly preferred compound A is a linear organopolysiloxane in which all siloxyl groups in the chain are functionalized by either a Si-H or a Si-epoxy group. It possesses at least three Si-H bonds. While not wishing to be bound by this theory, the inventors believe that compound A acts as both an adhesion promoter and a crosslinking agent.

[0042] Preferably, said compound A does not contain, or substantially does not contain, any alkoxy, vinyl, hydroxy or methacryloxy functional groups.

[0043] Advantageously, said compound A has a total number of siloxyl motifs between 7 and 30, preferably between 7 and 25, and even more preferably between 7 and 15.

[0044] According to a preferred mode, compound A consists of, or essentially consists of, siloxyl motifs selected from siloxyl motifs (1.1) to (1.3) as defined above, in which a=1 and b=1 or 2, c=1 and d=1 or 2, and the symbols Y and Z are as defined above.

[0045] According to another preferred embodiment, compound A consists of, or essentially consists of, siloxyl motifs selected from the siloxyl motifs (1.1) to (1.3) as defined above, in which a=1 and b=1 or 2, c=1 and d=1, and the symbols Y and Z are as defined above. According to a preferred embodiment of the invention, compound A has a molar ratio between the siloxyl motifs (1.1) and the siloxyl motifs (1.2) of between 0.5 and 4, preferably between 0.8 and 3, and even more preferably between 0.8 and 2.5.

[0046] Preferably, compound A has a siloxyl motif content (1.1) greater than or equal to 0.25 mol per 100 g of compound A and more preferably between 0.25 and 0.45 mol / 100 g of compound A. Even more advantageously, compound A has a siloxyl motif content (1.1) greater than or equal to 0.25 mol per 100 g of compound A and a siloxyl motif content (1.2) greater than or equal to 0.3 mol per 100 g of compound A. According to a still more advantageous modality, compound A has a siloxyl motif content (1.1) between 0.25 and 0.45 mol / 100 g of compound A and a siloxyl motif content (1.2) between 0.3 and 0.85 mol / 100 g of compound A.

[0047] Preferably, for the siloxyl motif (1.1), the symbol Y is chosen from the group consisting of hydrocarbon groups (Rl) to (R-6) of the following formulas:

[0048] According to a particularly preferred embodiment, in the siloxyl motif (1.1), the symbol Y is the hydrocarbon group (R-4) as defined above.

[0049] Compound A can be obtained by hydrosilylation of organic synthons comprising at least one hydrocarbon ring containing an oxygen atom with a linear organopolyhydrogenosiloxane not comprising (1,4) motifs as described above. These hydrosilylation reactions can be catalyzed by a platinum compound, in particular by carbon-supported platinum as described in EP patent 0904315 or by platinum complexes with carbene ligands as described in EP patent 1309647. Synthetic examples are described in US patent 10,676,574 B2.

[0050] On the other hand, compound B is chosen from organic zinc compounds and organic iron compounds. In one embodiment, compound B is chosen from organic zinc compounds. In another embodiment, compound B is chosen from organic iron compounds. Preferably, compound B is chosen from zinc or iron carboxylic acid salts. Compound B may be chosen from zinc carboxylic acid salts represented by the general formula (II) and iron carboxylic acid salts represented by the general formula (III): Zn(RC(O)O)2(II)

[0051] Fe (RC(O)O)3(III) in which R represents a hydrogen atom or a hydrocarbon group in C1 to C20, preferably R represents a hydrogen atom, a linear or branched alkyl group in C1 to C20, a cycloalkyl group in C1 to C20 optionally substituted by an alkyl group, or a linear or branched alkenyl group in C1 to C20.

[0052] It is understood in all the formulas described here that the R groups can be identical or different from each other, preferably identical.

[0053] According to one embodiment, compound B is selected from zinc carboxylic acid salts.

[0054] Compound B can be chosen from the zinc carboxylic acid salts represented by the general formula (II):

[0055] Zn (RC(O)O)2(II) in which R represents a hydrogen atom or a hydrocarbon group in C1 to C20, preferably R represents a hydrogen atom, a linear or branched alkyl group in C1 to C20, a cycloalkyl group in C1 to C20 optionally substituted by an alkyl group, or a linear or branched alkenyl group in C1 to C20; preferably R represents a linear or branched alkyl group in C1 to C20 or a linear or branched alkenyl group in C1 to C20.

[0056] According to another embodiment, compound B is chosen from iron carboxylic acid salts. Compound B can be chosen from iron carboxylic acid salts represented by the general formula (III):

[0057] Fe (RC(O)O)3(III) in which R represents a hydrogen atom or a hydrocarbon group in C20-Ci, preferably R represents a hydrogen atom, a linear or branched alkyl group in C20-Ci, a cycloalkyl group in C20-Ci optionally substituted by an alkyl group, or a linear or branched alkenyl group in C20-Cx; preferably R represents a linear or branched alkyl group in C20-Cx or a linear or branched alkenyl group in C20-Cx.

[0058] Compound B is selected from the group consisting of the following zinc carboxylic acid salts: zinc formate, zinc acetate, zinc propionate, zinc butanoate, zinc pentanoate, zinc ethylhexanoate, zinc naphthenate, zinc neodecanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc acrylate, zinc methacrylate, and zinc undecylenate; or in the group consisting of the following iron carboxylic acid salts: iron formate, iron acetate, iron propionate, iron butanoate, iron pentanoate, iron ethylhexanoate, iron naphthenate, iron neodecanoate, iron laurate, iron myristate, iron palmitate, iron stearate, iron acrylate, iron methacrylate and iron undecylenate.

[0059] According to a preferred embodiment, compound B is selected from the group consisting of iron neodecanoate, zinc neodecanoate, iron acetate, zinc acetate, iron acrylate and zinc acrylate.

[0060] In a highly preferred embodiment, compound B is iron neodecanoate or zinc neodecanoate. Neodecanoate is a mixture of constitutional isomers with the formula (C10H19O2). Preferably, neodecanoate is a mixture of constitutional isomers, including trialkylacetates (i.e., the carbon in the alpha position of the carbonyl group is a quaternary carbon). Examples of neodecanoate isomers include 2,2,3,5-tetramethylhexanoate, 2,4-dimethyl-2-isopropylpentanoate, 2,5-dimethyl-2-ethylhexanoate, and 2,2-dimethyloctanoate. Advantageously, iron neodecanoate and zinc neodecanoate disperse well in silicones. Therefore, it is not necessary to use a solvent to incorporate it into the silicone composition, although this is not excluded within the scope of the present invention.

[0061] Iron and zinc oxides and hydroxides are not included in the terms "organic iron compounds" and "organic zinc compounds." Therefore, the terms "organic iron compounds" and "organic zinc compounds" do not specifically include iron(II) and (III) oxides, iron(II) and (III) hydroxides, zinc oxides, zinc hydroxides, or pigments associated with these compounds.

[0062] According to one embodiment, compound B is not a P-type iron or zinc diketonate chelate. Preferably, the silicone composition according to the present invention does not contain any iron or zinc diketonate compound.

[0063] Preferably, the silicone composition according to the present invention does not contain any organic or organometallic titanium compounds. Preferably, the silicone composition according to the present invention contains neither titanium chelate nor titanium alkoxide. Most preferably, the silicone composition according to the present invention does not contain any of the following organic titanium compounds: titanium alkylates such as butyl titanate, isopropyl titanate, methyl titanate, and octyl titanate.

[0064] Preferably, the silicone composition according to the present invention does not contain any organic or organometallic compound of zirconium, in particular zirconium chelate or zirconium alkoxide.

[0065] Preferably, the silicone composition according to the present invention does not contain any organic or organometallic aluminum compound, in particular aluminum chelate or aluminum alkoxide.

[0066] In addition to the adhesion-promoting system, the silicone composition according to the present invention comprises at least one silicone base capable of crosslinking by polyaddition. Also known as hydrosilylation, the polyaddition reaction can be defined as the reaction of a compound comprising at least one double bond with a compound comprising at least one hydrogenosilyl group, i.e., a hydrogen atom bonded to a silicon atom. The polyaddition reaction is notably used to crosslink silicone compositions comprising organopolysiloxanes bearing alkenyl groups and organopolysiloxanes comprising hydrogenosilyl groups.

[0067] Preferably, the silicone base according to the present invention comprises:

[0068] - at least one organopolysiloxane C having, per molecule, at least two alkenyl groups in C2-C12 bonded to silicon,

[0069] - a catalytically effective amount of at least one D polyaddition catalyst.

[0070] Furthermore, the silicone base according to the present invention may optionally comprise at least one organohydrogenopolysiloxane E. However, this compound is only optional because compound A, which is part of the adhesion promoter system, has at least three Si-H bonds and can therefore also play the role of crosslinker.

[0071] Organopolysiloxane C, having at least two C2-C12 alkenyl groups linked to silicon per molecule, can preferably be an organopolysiloxane formed:

[0072] - of at least two siloxyl motifs of the following formula: R 1 m R 2 nSiO(4-mn) / 2 in which R 1 represents a C2-C12 alkenyl group, preferably a vinyl group; R 2represents 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, cycloalkyl groups having from 3 to 8 carbon atoms and aryl groups having from 6 to 12 carbon atoms; m = 1 or 2, n = 0, 1 or 2 and the sum m+n = 1, 2 or 3, and

[0073] - possibly with the following formula patterns: R 2 o SiO(4- O ) / 2 in which R 2 has the same meaning as above and o = 0, 1, 2 or 3.

[0074] It is understood in the formulas above that, if several groups R 1 or R 2 are present, they may be identical or different from each other.

[0075] In the following section concerning the description of the organopolysiloxane C having, per molecule, at least two C2-C12 alkenyl groups linked to silicon, the following nomenclature has been used to represent the siloxyl motifs:

[0076] M: siloxyl motif R SiOw,

[0077] M V1 : siloxyl motif chosen from R 1 R 2 2SiOi / 2 and R 1 2R 2 SiOi / 2,

[0078] D: siloxyl motif R 2 2SiC>2 / 2,

[0079] D V1 : siloxyl motif chosen from R^SiCl^ and R 1 R 2 SiÛ2 / 2,

[0080] T: siloxyl motif R 2 SiC>3 / 2,

[0081] Q: SiC>4 / 2 siloxyl motif, with R 1 and R 2 such as: R 1 represents a C2-C12 alkenyl group, preferably a vinyl group; R 2represents 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, cycloalkyl groups having from 3 to 8 carbon atoms and aryl groups having from 6 to 12 carbon atoms.

[0082] As examples of terminal motifs M and M V1 Examples include trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy, and dimethylhexylsiloxy.

[0083] As examples of patterns D and D V1 Examples include dimethylsiloxy, methylphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyldecenylsiloxy or methyldecadienylsiloxy.

[0084] Examples of T motifs include the methylsiloxy group.

[0085] It is understood in the formulas above that, if several groups R 1 or R 2are present, they may be identical or different from each other.

[0086] The organopoly siloxane C according to the invention has, per molecule, at least two C2-C12 alkenyl groups linked to silicon. Preferably, the organopoly siloxane C has a mass content of alkenyl motifs of between 0.001% and 30%, preferably between 0.01% and 10%, preferably between 0.02% and 5%, and even more preferably between 0.05% and 1% (mass percentage of alkenyl motifs, based on the total weight of the organopoly siloxane).

[0087] Preferably, the organopoly siloxane C, having at least two C2-C12 alkenyl groups linked to silicon per molecule, may have a linear structure. By "linear structure" is meant a structure that does not contain, or substantially does not contain, siloxy T and / or Q motifs. It may consist essentially of siloxyl motifs selected from M, M V1 , D, D V1, and their combinations. Preferably, it can be a linear organopolysiloxane formed of at least two siloxyl M motifs V1 and patterns D.

[0088] Preferably, said organopolysiloxanes having, per molecule, at least two C2-C12 alkenyl groups linked to silicon are oils with a dynamic viscosity between 50 mPa.s and 100000 mPa.s, preferably between 100 mPa.s and 80000 mPa.s, and more preferably between 1000 mPa.s and 60000 mPa.s.

[0089] Examples of linear organopolysiloxanes that could be a C organopolysiloxane having, per molecule, at least two C2-C12 alkenyl groups linked to silicon according to the invention are:

[0090] - a poly(dimethylsiloxane) with dimethylvinylsilyl ends;

[0091] - a poly(dimethylsiloxane-co-methylphenylsiloxane) with dimethylvinylsilyl ends;

[0092] - a poly(dimethylsiloxane-co-methylvinylsiloxane) with dimethylvinylsilyl ends; and

[0093] - a poly(dimethylsiloxane-co-methylvinylsiloxane) with trimethylsilyl ends; the poly(dimethylsiloxane) with dimethylvinylsilyl ends being particularly preferred.

[0094] According to a first embodiment, the silicone base according to the invention comprises only a linear C organopolysiloxane having, per molecule, at least two C2-C12 alkenyl groups linked to silicon, or a mixture of several linear C organopolysiloxanes having, per molecule, at least two C2-C12 alkenyl groups linked to silicon. According to this first embodiment, said silicone base does not comprise, or substantially does not comprise, any organopolysiloxane(s) having, per molecule, at least two C2-C12 alkenyl groups linked to silicon having a branched structure. By “branched structure,” we mean a structure that contains T and / or Q siloxy motifs.

[0095] According to a second embodiment, the silicone base according to the invention comprises a mixture of at least one linear organopolysiloxane C having, per molecule, at least two C2-C12 alkenyl groups linked to silicon and at least one branched organopolysiloxane C having, per molecule, at least two C2-C12 alkenyl groups linked to silicon.

[0096] Branched organopolysiloxanes, sometimes identified as silicone resins, are well-known and commercially available compounds. They are typically available in diluted form, preferably in vinyl silicone oil or a silicone oil and silicone gum mixture, or in a solvent, for example, xylene.

[0097] In a branched organopolysiloxane, the alkenyl groups may be located on M, D, or T siloxyl motifs. Examples of branched organopolysiloxanes having, per molecule, at least two C2-C12 alkenyl groups linked to silicon according to the invention are:

[0098] - MD V1 Q, where vinyl groups are included in patterns D,

[0099] - MD V1 T, where vinyl groups are included in patterns D,

[0100] - MD V1 TQ, where vinyl groups are included in patterns D,

[0101] - MM V1 Q, where vinyl groups are included in part of patterns M,

[0102] - MM V1 T, where vinyl groups are included in part of the M patterns,

[0103] - MM V1 TQ, where vinyl groups are included in part of the M patterns,

[0104] - MM V1 DD V1Q, where vinyl groups are included in patterns M and D,

[0105] - MM V1 DD V1 T, where vinyl groups are included in patterns M and D,

[0106] - MM V1 DD V1 TQ, where vinyl groups are included in patterns M and D,

[0107] - and their mixtures; the MM compounds V1 Q and MD V1 Q being particularly preferred.

[0108] The polyaddition catalyst D can be chosen from platinum and rhodium compounds, but also from silicon compounds such as those described in patent applications WO 2015 / 004396 and WO 2015 / 004397, germanium compounds such as those described in patent application WO 2016 / 075414, nickel, cobalt, or iron complexes such as those described in patent applications WO 2016 / 071651, WO 2016 / 071652, WO 2016 / 071654, WO 2018 / 115601, WO 2019 / 008279, WO 2019 / 138194, WO 2023 / 031524, and WO 2023 / 031525, or manganese complexes such as those described in applications WO 2023 / 139322 and WO 2024 / 146993. The catalyst is preferably a compound derived from at least one metal belonging to the platinum group. These catalysts are well known. In particular, complexes of platinum and an organic product described in US patents 3,159,601, 3,159,602, 3,220,972 and European patents EP 0.057.459, EP 0.188.978 and EP 0.190 can be used.530, the platinum and vinyl organosiloxane complexes described in US patents 3,419,593, 3,715,334, 3,377,432 and 3,814,730.

[0109] Preferably, the polyaddition catalyst is a platinum-derived compound. In this case, the mass amount of catalyst, calculated by weight of platinum-metal, is generally between 2 ppm and 400 ppm by mass, preferably between 5 ppm and 200 ppm, based on the total weight of the silicone composition.

[0110] Preferably, the D polyaddition catalyst is a Karstedt platinum.

[0111] The silicone composition according to the present invention may optionally comprise an organohydrogenopolysiloxane E compound, which is an organopolysiloxane having, per molecule, at least two SiH motifs. Preferably, the organohydrogenopolysiloxane E compound comprises at least three SiH motifs.

[0112] The organohydrogenopolysiloxane E may advantageously be an organopolysiloxane comprising at least two, preferably at least three, siloxyl units of the following formula: H p R 3 q SiO(4- P-q ) / 2 in which R 3 represents a monovalent radical having from 1 to 12 carbon atoms, p = 1 or 2, q = 0, 1 or 2 and p+q = 1, 2 or 3; and possibly other motifs of the following formula: R 2 r SiO(4- r ) / 2 in which R 2 has the same meaning as above, and r = 0, 1, 2, or 3.

[0113] It is understood that, if several R groups 2 or R 3 are present in the formulas above, they may be identical or different from each other.

[0114] Preferably, R 3can represent a monovalent radical chosen from the group consisting of alkyl groups having 1 to 8 carbon atoms, possibly 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 3 can advantageously be chosen from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl.

[0115] The symbol p is preferably equal to 1.

[0116] In the following section concerning the description of organohydrogenopolysiloxane E, the following nomenclature has been used to represent the siloxyl motifs:

[0117] M: siloxyl motif R SiOw,

[0118] M': siloxyl motif R 3 2HSiOi / 2,

[0119] D: siloxyl motif R 2 2SiC>2 / 2,

[0120] D': siloxyl motif R 3 HSiC>2 / 2,

[0121] T: siloxyl motif R 2 SiC>3 / 2,

[0122] Q: SiC>4 / 2 siloxyl motif, with R 2 and R 3 as defined previously. Organohydrogenopolysiloxane E 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. Preferably, the viscosity of organohydrogenopolysiloxane E 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.

[0123] In the case of linear polymers, these are essentially composed of D and / or D' siloxyl units, and terminal M and / or M' siloxyl units. In the case of cyclic polymers, these are essentially composed of D and / or D' siloxyl units. Examples of organohydrogenopolysiloxanes that could be organohydrogenopolysiloxanes E according to the invention are:

[0124] - a poly(dimethylsiloxane) with hydrogenodimethylsilyl ends;

[0125] - a poly(dimethylsiloxane-co-methylhydrogenosiloxane) with trimethylsilyl ends;

[0126] - a poly(dimethylsiloxane-co-methylhydrogenosiloxane) with hydrogenodimethylsilyl ends;

[0127] - a poly(methylhydrogenosiloxane) with trimethylsilyl ends; and

[0128] - a cyclic poly(methylhydrogenosiloxane).

[0129] When the organohydrogenopolysiloxane E has a branched structure, it is preferably chosen from the group consisting of silicone resins with the following formulas:

[0130] - M'Q where hydrogen atoms bonded to silicon atoms are carried by the M groups;

[0131] - MM'Q where hydrogen atoms bonded to silicon atoms are carried by part of the M motifs;

[0132] - MD'Q where hydrogen atoms bonded to silicon atoms are carried by the D groups;

[0133] - MDD'Q where hydrogen atoms bonded to silicon atoms are carried by a part of the D groups;

[0134] - MM'TQ where hydrogen atoms bonded to silicon atoms are carried by part of the M motifs;

[0135] - MM'DD'Q where hydrogen atoms bonded to silicon atoms are carried by part of the M and D motifs;

[0136] - and their mixtures.

[0137] Preferably, the organohydrogenopolysiloxane E has a mass content of hydrogenosilyl functions SiH between 0.2% and 91% more preferably between 3% and 80% and even more preferably between 15% and 70%.

[0138] The organohydrogenopolysiloxane E according to the invention can be a mixture of several organohydrogenopolysiloxanes E of different structure, for example of one or more linear organohydrogenopolysiloxanes and one or more resins.

[0139] In addition to the silicone base capable of crosslinking by polyaddition and an adhesion-promoting system, the silicone composition according to the invention may further comprise other compounds, in particular:

[0140] - at least one mineral filler, including silica, quartz, calcium carbonate, or a mixture thereof;

[0141] - a crosslinking inhibitor;

[0142] - a coloring base;

[0143] - optionally other charges.

[0144] The choice and quantity of fillers and additives used depends in particular on the intended application.

[0145] According to a preferred embodiment, the silicone composition comprises one or more mineral fillers.

[0146] A typically used mineral filler is combustion silica or precipitation silica. Silica-type mineral fillers preferably have a specific surface area, measured using BET methods, of at least 10 m². 2 / g, notably between 50 m 2 / g and 400 m 2 / g, preferably greater than 70 m 2 / g, an average primary particle size of less than 0.1 pm (micrometer) and an apparent density of less than 200 g / liter. Preferably, the mineral feedstock is combustion silica with a specific surface area between 10 m² 2 / g and 300 m 2 / g.

[0147] Mineral fillers of the silica type, preferably hydrophilic, can be incorporated directly into the silicone composition or optionally treated with a compatibilizing agent. Alternatively, these silicas can be treated with one or more organosilicon compounds, for example organosilane or organosilazane, commonly used for this purpose. These compounds include methylpolysiloxanes such as hexamethyldisiloxane, octamethylcyclo-tetrasiloxane, methylpolysilazanes such as hexamethyldisilazane, hexamethylcyclotrisilazane, tetramethyldivinyldisilazane, chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, dimethylvinylchlorosilane, alkoxysilanes such as dimethyldimethoxysilane, dimethylvinylethoxysilane, trimethyhnethoxysilane.These compounds can be used alone or in mixtures (see French patents FR 1 126 884, FR 1 136 885, FR 1 236 505 and English patent GB 1 024 234).

[0148] Silica can optionally be pre-dispersed in a silicone oil to obtain a suspension. A preferred method is to use a treated combustion silica suspension, notably with hexamethyldisilazane, in a polyorganosiloxane oil, particularly a vinylized one.

[0149] Alternatively or in addition, the silicone composition according to the invention may also contain at least one other mineral filler, namely quartz. Preferably, natural ground quartz with an average particle size of less than 10 microns is used. The quartz may optionally be treated to improve its compatibility with organopolysiloxanes.

[0150] Alternatively or in addition, the silicone composition according to the invention may also contain at least one other mineral filler, namely calcium carbonate. The calcium carbonate may optionally be surface-treated with an organic acid or an ester of an organic acid. Other mineral fillers may be considered, including semi-reinforcing and / or filler fillers, such as diatomaceous earth and / or kaolin, calcined clay, talc, huntites and hydromagnesites, rutile-type titanium dioxide, oxides and hydroxides of iron, zinc, chromium, zirconium, magnesium, various forms of alumina (hydrated or not), boron nitride, lithopone, barium metaborate, barium sulfate, and glass microspheres. These fillers are coarser, generally with an average particle diameter greater than 0.1 pm (micrometer) and a specific surface area generally less than 30 m². 2 / g. These charges may have been modified on the surface by treatment with the various organosilicon compounds usually employed for this purpose.

[0151] According to one embodiment, the silicone composition according to the invention may optionally include a crosslinking inhibitor. The function of the inhibitor is to slow down the polyaddition reaction. The crosslinking inhibitor may be selected from the following compounds:

[0152] - an organopolysiloxane, advantageously cyclic, and substituted by at least one alkenyl, tetramethylvinyltetrasiloxane being particularly preferred,

[0153] - pyridine,

[0154] - organic phosphines and phosphites,

[0155] - unsaturated amides,

[0156] - alkylated maleates, and

[0157] - acetylenic alcohols.

[0158] Preferably, the crosslinking inhibitor is an acetylenic alcohol of formula (R 1 (R 2 )C(OH)- C=CH, in which:

[0159] - R 1 is a linear or branched alkyl radical, or a phenyl radical,

[0160] - R 2 is a hydrogen atom, a linear or branched alkyl radical, or a phenyl radical,

[0161] - the radicals R 1 , R 2 and the carbon atom located alpha to the triple bond, which may eventually form a ring, and

[0162] - the total number of carbon atoms contained in R 1 and R 2 being at least 5, preferably from 9 to 20.

[0163] These alcohols are preferably chosen from those having a boiling point above 250°C. Examples of commercially available products include: 1-ethyl-1-cyclohexanol, 3-methyl-3-dodecyne-1-ol, 3,7,1-trimethyl-3-dodecyne-1-ol, 1,1-diphenyl-1,1-propyne-2-ol, 3-ethyl-6-nonyne-1-ol, and 3-methyl-3-pentadecyne-1-ol. Preferably, the crosslinking inhibitor is 1-ethyl-1-cyclohexanol.

[0164] The presence of the inhibitor may or may not be necessary depending on the silicone composition and the process used. If required, such a crosslinking inhibitor can typically be present at a maximum concentration of 3000 ppm, preferably 100 ppm to 2000 ppm, relative to the total weight of the silicone composition. The silicone composition may optionally include at least one diorganopolysiloxane gum. Diorganopolysiloxane gums are linear polymers with a high molecular weight and a viscosity greater than 1000 Pa·s at 25°C, preferably greater than 2000 Pa·s, and whose diorganopolysiloxane chain consists primarily of R₂S₁O₂₂ units, blocked at each end by R₂SiO₂ units. The R radical represents an alkyl radical with 1 to 8 carbon atoms or an alkenyl radical with 2 to 6 carbon atoms.The presence, along the diorganopolysiloxane chain, of small amounts of motifs other than R₂SiO₂ / ₂, for example RSiCh / ₂ and / or SiO₂ motifs, is not excluded, however, in a proportion of up to 2% relative to the number of R₂SiO₂ / ₂ motifs. Preferably, diorganopolysiloxane gums comprise at least two C₂-Ci₂ alkenyl groups bonded to silicon. Advantageously, the diorganopolysiloxane gum has a vinylized motif content greater than 0.3% by mass, preferably greater than 0.5%, more preferably between 0.5% and 6%, even more preferably between 0.5% and 4%, and even more preferably between 1% and 3.5%.

[0165] The silicone composition may optionally include at least one non-reactive diorganopolysiloxane oil, in particular free of alkenyl or hydrogenosilyl groups. Preferably, these are α,co-bis(triorganosiloxy)diorganopolysiloxane polymers with a viscosity between 10 mPa.s and 1000 Pa.s at 25°C, formed essentially of diorganosiloxy units, with the organic radicals bonded to the silicon atoms being selected from among the methyl and phenyl radicals.

[0166] The silicone composition may optionally include at least one heat-resistant and / or fire-resistant additive. These heat-resistant and / or fire-resistant additives are well known to those skilled in the art. They may be advantageously chosen from the group consisting of: salts, oxides, and hydroxides of metals such as iron, titanium, aluminum, nickel, and copper; salts, hydroxides, and oxides of rare earth elements such as cerium and lanthanum; organophosphate compounds; platinum derivatives; carbon black; and calcium, aluminum, and / or potassium silicates such as mica and wollastonite. Hydrated mineral fillers, oxides or carbonates of calcium, magnesium, or aluminum, such as magnesium hydroxide (Mg(OH)₂) and aluminum hydroxide (Al(OH)₂), may also be mentioned. hydromagnesite with the empirical formula Mg5(CO3)4(OH)2.4H2O, and calcium hydroxide.According to another embodiment, hollow glass microspheres can be added to the silicone composition.

[0167] According to one embodiment, the silicone composition according to the present invention may optionally include other additives traditionally used in this technical field by those skilled in the art, for example an additional adhesion promoter, a stabilizing additive (for example a silylated derivative of phosphoric acid such as silylated esters of phosphoric acid), a colorant, a rheological agent such as a thixotropic agent, etc.

[0168] However, according to a preferred embodiment, the silicone composition according to the present invention preferably does not comprise any additional adhesion promoter, in addition to the adhesion promoter system as described above. In particular, the silicone composition according to the present invention preferably contains less than 2% by weight, more preferably less than 1% by weight, and even more preferably does not contain any silane-type adhesion promoter, especially an organoalkoxysilane compound comprising at least one epoxy group. Examples include 3-glycidoxypropyl-trimethoxysilane, 3-glycidoxypropyl-triethoxysilane, 3-glycidoxypropyl-methyldimethoxysilane, 4-glycidoxybutyl-trimethoxysilane, 5,6-epoxyhexyl-triethoxysilane, 2-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, and 2-(3,4-epoxy-cyclohexyl)-ethyltriethoxysilane.

[0169] The concentrations of the different elements of the silicone composition according to the invention are preferably as indicated below:

[0170] Compared to the total weight of the silicone composition, the silicone base, which includes any fillers, preferentially represents 83% to 97.95%, preferentially 83% to 97.9% by weight, more preferentially 88.5% to 95.8% by weight, and even more preferentially 91% to 95.6% by weight, while the adhesion promoter system preferentially represents 2.05% to 17% by weight, preferentially 2.1% to 17% by weight, more preferentially 4.2% to 11.5% by weight, and even more preferentially 4.4% to 9% by weight.

[0171] Relative to the total weight of the silicone composition, organopolysiloxane compound A having at least 2 epoxy groups and at least 3 hydrogenosilyl groups preferentially represents 2% to 15% by weight, more preferably 4% to 10% by weight, and even more preferably 5% to 8% by weight, while compound B chosen from organic zinc compounds and organic iron compounds preferentially represents 0.05% to 2% by weight, more preferably 0.1% to 2% by weight, more preferably 0.2% to 1.5% by weight, and even more preferably 0.3% to 0.8% by weight.

[0172] According to one embodiment, the silicone composition according to the invention comprises (by weight relative to the total weight of the silicone composition):

[0173] - from 2% to 15% by weight of at least one organopolysiloxane compound A having at least 2 epoxy groups and at least 3 hydrogenosil groups,

[0174] - from 0.05% to 2% by weight, preferably from 0.1% to 2% by weight of at least one compound B chosen from organic zinc compounds and organic iron compounds,

[0175] - from 40% to 98% by weight, preferably from 50% to 95% by weight, of at least one organopolysiloxane C having, per molecule, at least two alkenyl groups in C2-C12 bonded to silicon,

[0176] - from 2 ppm to 400 ppm of at least one platinum-derived D polyaddition catalyst (by weight of platinum-metal),

[0177] - from 0% to 20% by weight of at least one organohydrogenopolysiloxane E having, per molecule, at least two SiH motifs.

[0178] The weight amounts of organopolysiloxanes C, and optionally E, are determined such that the value of the ratio RHAlk falls within the following range: 0.5 < RHAlk < 10, more preferably 1 < RHAlk < 8, and even more preferably 2 < RHAlk < 6. RHAlk = nH / tAlk, where nH is the number of moles of hydrogen atoms directly bonded to a silicon atom in the silicone composition and tAlk is the number of moles of alkenyl directly bonded to a silicon atom in the silicone composition. The SiH functional groups are provided by compound A and optionally by organohydrogenosiloxane E. The alkenyl functional groups are provided by organopolysiloxane(s) C.

[0179] The silicone composition according to the present invention may further comprise (by weight relative to the total weight of the silicone composition):

[0180] - from 0% to 50% by weight, more preferably from 5% to 40% by weight, even more preferably from 10% to 30% by weight of at least one mineral filler, in particular silica, quartz, calcium carbonate, or a mixture of these.

[0181] The presence of a crosslinking inhibitor may or may not be necessary depending on the silicone composition and the process used. If required, such a crosslinking inhibitor can typically be present at a maximum concentration of 10,000 ppm, preferably at a concentration of 10 ppm to 2,000 ppm by weight of the total silicone composition.

[0182] The silicone composition according to the invention can be prepared from a two-component (or multi-component) system characterized in that it is in two (or more) distinct parts intended to be mixed to form said silicone composition. In particular, in the case of preferred silicone compositions as described above, the silicone composition can be prepared from a two-component system characterized in that one part comprises catalyst D and does not comprise compound A, nor optional organohydrogenopolysiloxane E, while the other part comprises compound A, and optionally organohydrogenopolysiloxane E, and does not comprise catalyst D. Other multi-component systems may be provided to improve shelf life and / or optimize the viscosity of each of the components.A two-component system, characterized in that it is presented in two distinct parts intended to be mixed to form said silicone composition according to the invention, is an object of the present invention.

[0183] After mixing in the case of a two-component or multi-component system, the silicone composition can be used according to the present invention. The viscosity of the silicone composition is preferably between 5000 mPa·s and 100000 mPa·s, more preferably between 10000 mPa·s and 50000 mPa·s.

[0184] Furthermore, the present invention relates to a method for preparing an article comprising a silicone elastomer layer on a textile substrate, comprising the following steps: a) preparing a silicone composition as described above; b) depositing said silicone composition onto said textile substrate; c) crosslinking said silicone composition to obtain the silicone elastomer on the textile substrate. The textile substrate according to the invention is a flexible substrate that may be of natural, artificial, synthetic, or mixed origin. The textile substrate may be a woven, knitted, or non-woven textile. "Non-woven" means any structure made of textile materials, such as fibers, continuous filaments, or chopped yarns, regardless of their nature or origin, formed into a web by any means, and bonded by any means, excluding the interlacing of yarns.Non-woven textiles are manufactured by processes other than spinning, weaving, knitting, or knotting. Preferably, the backing is a woven or knitted textile, and more preferably a woven textile.

[0185] The textile supports used in the present invention are advantageously based on thermoplastic polymers. By way of example, suitable thermoplastic (co)polymers for the purposes of the invention include:

[0186] - polyamides, such as polyamide 6, polyamide 6-6, polyamide 4, polyamide 1-1, polyamide 1-2, polyamides 4-6, 6-10, 6-12, 6-36, 12-12, their copolymers and mixtures,

[0187] - polyesters, in particular poly(alkylene phthalate or terephthalate), such as polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polybutylene terephthalate (PBT), their copolymers and mixtures,

[0188] - polyolefins, such as polyethylene and polypropylene,

[0189] - polyimides and polyamide-polyimide, as well as mixtures and / or alloys of all these (co)polymers.

[0190] The textile support according to the invention is preferably made of polyester or polyamide.

[0191] In the field of airbags, the overall yarn count of the fabric or knit is usually between 100 dtex and 950 dtex (decitex). Preferably, the overall yarn count of the fabric or knit is between 350 dtex and 750 dtex. The fabric or knit used as a substrate in the invention advantageously has a weight before coating of between 150 g / m² 2 and 250 g / m 2 . Ideally, a polyamide fabric with these characteristics should be selected.

[0192] Preferably, the support in the present invention is a textile support known as "loomstate", that is to say a woven or knitted textile support obtained directly from the loom and not having undergone a washing step intended to remove the lubricating or sizing compositions used during weaving, nor a heat-fixing step.

[0193] In step b of the process of preparing an article comprising a layer of silicone elastomer according to the invention, the silicone composition is deposited on said textile support.

[0194] The deposit can be made over the entire surface or over one or more parts of that surface.

[0195] Preferably, the amount of silicone composition deposited is determined so as to obtain a silicone elastomer layer of between 10 g / m 2 and 150 g / m 2 of support, preferably between 10 g / m 2 and 50 g / m2 .

[0196] Examples of techniques for depositing silicone composition include coating techniques carried out by squeegee, in particular by cylinder squeegee, air squeegee and carpet squeegee, or by scrimping, i.e. by scrimping between two rollers, or by licking roller, rotary frame, reverse roll or transfer, by spraying, or by curtain coating.

[0197] In step c of the process according to the invention, the deposited silicone composition is crosslinked into a silicone elastomer. The crosslinking time can vary depending, in particular, on the silicone composition and the temperature of the crosslinking step. Generally, an elastomer with good properties is obtained in a few minutes or less, depending on the temperature and the concentration of catalyst and inhibitor in the silicone composition. The silicone composition can crosslink without external intervention if the reactivity between the previously contacted parts is sufficient. However, in the process according to the invention, it is preferable to thermally activate the crosslinking reaction. Methods for thermally activating the crosslinking are conventional ovens (for example, tunnel ovens), heated laminating rollers, or infrared sources.This thermal activation can be complemented by actinic activation and / or electron bombardment. The crosslinking temperature can exceed 120°C, without exceeding the substrate's degradation temperature, preferably between 160°C and 210°C, for a duration of less than 5 minutes.

[0198] After curing, the silicone elastomer forms a layer on the textile substrate. The thickness of this layer can range from 10 µm to 150 µm, preferably between 10 µm and 50 µm.

[0199] Another object of the present invention relates to an article comprising a layer of silicone elastomer on a textile support obtained or obtainable by the process described above. Most preferably, said article is an airbag. However, other applications are not excluded, for example the manufacture of tent canvases, parachute canopies and the like, as well as the manufacture of fabrics that can be used for textile architectural elements or furnishing fabrics (for example for shelters, mobile structures, textile buildings, partitions, flexible doors, tarpaulins, tents, stands, marquees, furniture, cladding, advertising screens, windbreaks, filter panels, sunshades, ceilings, blinds, etc.), the manufacture of artificial leather, and in general any heat-resistant technical textile.

[0200] Another object of the present invention relates to the use of the silicone composition as described above for coating textile support.

[0201] Furthermore, another object of the present invention relates to the use, in a silicone composition, of an adhesion-promoting system comprising

[0202] - at least one organopolysiloxane compound A having at least 2 epoxy groups and at least 3 hydrogenosilyl groups, and

[0203] - at least one compound B selected from organic zinc compounds and organic iron compounds, to improve the adhesion of said silicone composition to a textile substrate. The inventors have observed that the adhesion-promoting system according to the invention not only achieves very good performance in terms of adhesion between the textile substrate and the silicone elastomer layer, but also reduces the release of volatile compounds and the odors associated with these releases.

[0204] According to one embodiment, the silicone composition according to the invention may contain a low level of volatile organic compounds. Volatile organic compounds (VOCs) are organic compounds that can readily exist in gaseous form in the Earth's atmosphere. According to European Union directives, a volatile organic compound is defined as any organic compound having a vapor pressure of 0.01 kPa or more at a temperature of 20°C. Silicone compositions comprising an adhesion promoter system according to the prior art typically include an organic titanium compound, for example, butyl titanate, isopropyl titanate, or methyl titanate. However, these compounds are likely to emit alcohols such as butanol, isopropanol, or methanol, which are considered VOCs, during the use of the silicone composition.According to one embodiment, the present invention advantageously reduces the quantity, or even eliminates, certain compounds in the silicone composition that are likely to emit VOCs. The maximum theoretical level of VOCs emitted by the silicone composition can be reduced by at least 50%, or even 75%, compared to a silicone composition according to the prior art, while preserving the other properties of the composition, particularly adhesion. Furthermore, the reduction in the emission of alcohols such as butanol, isopropanol, or methanol leads to a decrease in odors associated with these molecules and a reduction in the chemical risks related to their flammability.

[0205] Furthermore, the present invention offers a solution to the depletion of titanium resources. Titanium is indeed listed among the critical and strategic raw materials of the European Union. Therefore, the fact that it is possible to eliminate the need for a titanium compound in the composition according to the invention is a major advantage. In this way, the present invention contributes significantly to the sustainable management and efficient use of natural resources. This efficient use of resources is part of a circular economy approach.

[0206] Other details or advantages of the invention will become clearer in view of the examples given below, which are for illustrative purposes only.

[0207] Examples

[0208] The silicone compositions described in the example below were obtained from the following raw materials:

[0209] Cl: vinylized polydimethylsiloxane chain-end oil, medium viscosity 40,000 mPa.s C2: organopolysiloxane resin of formula MM V1 Q containing 2.7% by weight of vinyl groups; D: Karstedt platinum catalyst, containing 10% by weight of platinum-metal

[0210] E: Poly(methylhydrogeno)(dimethyl)siloxane oil with SiH groups in the middle of the chain, having a SiH content of 20% by weight, viscosity = 20 mPa·s

[0211] ECH: 1-ethynyl-l-cyclohexanol

[0212] CaC₂O₅: untreated precipitated calcium carbonate with an average equivalent diameter of 2.0 pm.

[0213] BC: coloring base.

[0214] Components tested as adhesion promoters:

[0215] - Additive A: organopolysiloxane consisting of trimethylsiloxyl motifs (CTE SiOia), methylhydrogenosiloxy (CH3)HSiC>2 / 2 motifs, and epoxy-functional siloxyl motifs Y(CH3)SiC>2 / 2,

[0216] - GLYMO: glycidoxypropyltrimethoxysilane

[0217] - VTMO: vinyltrimethoxysilane

[0218] - TBOT: butyl titanate Ti(OBu)4, molecular weight: 340.3 g / mol

[0219] - Fe-ND: iron neodecanoate FeCl₂HigCE₂, molecular weight: 569.6 g / mol, at 85% by weight in a solvent

[0220] - Zn-ND: zinc neodecanoate Zn(ClO2)2, molecular weight: 407.9 g / mol

[0221] - Bi-ND: bismuth neodecanoate Bi(ClO2)3, molecular weight: 722.8 g / mol, at 60% by weight in a solvent

[0222] - Zn-Ace: zinc acetate Zn₂H₅Ch, molecular weight: 183.5 g / mol

[0223] - Fe-Acr: iron acrylate Fe^HsCh, molecular weight: 269.0 g / mol

[0224] Examples 1-4 and comparative examples C1 to C6:

[0225] Silicone compositions corresponding to parts PI and P2 were prepared by mixing the different compounds according to the quantities indicated in Tables 1 and 2 below, then the parts PI and P2 thus obtained were mixed respecting the mass proportion of 10 parts by weight of PI for 1 part by weight of P2.

[0226] [Table 1]

[0227] [Table 2]

[0228] After mixing, the silicone composition was deposited onto a textile support and coated using a laboratory coating machine, previously set to ensure a coating of 30 ± 5 g / m². 2 The textile support was a PET loomstate.

[0229] The coating was then crosslinked at 200°C for 1 minute.

[0230] The tests were carried out according to the measurement protocols described below: Initial abrasion: The adhesion between the textile substrate and the elastomeric coating was evaluated by performing an abrasion test on the samples after curing according to ISO 5981 (ISO 5981:2007: Rubber- or plastic-coated textile substrates - Determination of resistance to wrinkling due to the simultaneous application of torque and friction). The appearance of the sample was visually inspected after a series of 600 wrinkling cycles. "OK" means that the sample is visibly in good condition: the silicone coating still adheres correctly to the textile. "NOT OK" means that the sample is visibly damaged.

[0231] Abrasion after aging: Identical to the initial abrasion, but applied to a sample aged for 408 hours at 70°C, 95% RH. Odor and alcohol release: "NO" means that no odor is released from the sample or that the odor is very faint. "YES" means that the sample has a characteristic alcohol odor.

[0232] The results are presented in Tables 3 and 4 below.

[0233] [Table 3]

[0234] [Table 4]

Claims

DEMANDS 1. Silicone composition comprising at least a silicone base capable of polyaddition crosslinking and an adhesion-promoting system, said adhesion-promoting system comprising: - at least one organopolysiloxane compound A having at least 2 epoxy groups and at least 3 hydrogenosilyl groups, and - at least one compound B chosen from among the organic compounds of zinc and the organic compounds of iron.

2. Silicone composition according to claim 1, wherein compound A is a linear organopolysiloxane comprising siloxyl motifs (1.1) to (1.3) of the following formulas: Y a ZbSiO(4-ab) / 2 (II) H c Z d SiO(4- c -d) / 2 (1.2) Z3S1O1 / 2 (1.3) in which: a=l and b=l or 2 c=l and d=l or 2 and not comprising siloxyl motifs (1.4) to (1.6) of the following formulas: Z2S1O2 / 2 (1.4) ZSiO3 / 2 (1.5) S1O4 / 2 (1.6) the symbol Y representing a radical comprising a hydrocarbon group having from 2 to 20 carbon atoms and an epoxy function, optionally with one or more heteroatoms such as an oxygen atom; preferably the symbol Y is a radical selected from the group consisting of: alkylglycidyl ether, linear, branched or cyclic epoxyalkyl, linear, branched or cyclic epoxyalkenyl and glycidyl ester of carboxylic acid, the symbol Z representing a monovalent hydrocarbon group having from 1 to 30 carbon atoms, preferably selected from the group consisting of: alkyl groups having from 1 to 8 carbon atoms and aryl groups having from 6 to 12 carbon atoms; and more preferably chosen from the group consisting of: methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl, with the condition that compound A comprises, per molecule, at least 2 siloxyl motifs (1.1) bearing epoxyfunctional hydrocarbon groups and at least 3 siloxyl motifs (1.2) bearing hydrogenosiloxyl groups.

3. Silicone composition according to claim 1 or claim 2, wherein compound B is selected from zinc carboxylic acid salts represented by general formula (II) and iron carboxylic acid salts represented by general formula (III): Zn (RC(O)O)2(II) Fe (RC(O)O)3(III) in which R represents a hydrogen atom or a hydrocarbon group in C1 to C20.

4. Silicone composition according to claim 3, wherein R represents a hydrogen atom, a linear or branched C1 to C20 alkyl group, a C1 to C20 cycloalkyl group optionally substituted by an alkyl group, or a linear or branched C2 to C20 alkenyl group.

5. Silicone composition according to any one of claims 1 to 4, wherein compound B is selected from zinc carboxylic acid salts.

6. Silicone composition according to claim 5, wherein compound B is selected from the group consisting of the following zinc carboxylic acid salts: zinc formate, zinc acetate, zinc propionate, zinc butanoate, zinc pentanoate, zinc ethylhexanoate, zinc naphthenate, zinc neodecanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc acrylate, zinc methacrylate, and zinc undecylenate; preferably compound B is selected from the group consisting of zinc neodecanoate, zinc acetate, and zinc acrylate.

7. Silicone composition according to any one of claims 1 to 4, wherein compound B is selected from iron carboxylic acid salts.

8. Silicone composition according to claim 7, wherein compound B is selected from the group consisting of the following iron carboxylic acid salts: iron formate, iron acetate, iron propionate, iron butanoate, iron pentanoate, iron ethylhexanoate, iron naphthenate, iron neodecanoate, iron laurate, iron myristate, iron palmitate, iron stearate, iron acrylate, iron methacrylate and iron undecylenate; preferably compound B is selected from the group consisting of iron neodecanoate, iron acetate and iron acrylate.

9. Two-component system, characterized in that it is presented in two distinct parts intended to be mixed to form said silicone composition according to any one of claims 1 to 8.

10. A method for preparing an article comprising a layer of silicone elastomer on a textile support, comprising the following steps: a) preparing a silicone composition as described in any one of claims 1 to 8; b) depositing said silicone composition on said textile support; c) crosslinking said silicone composition to obtain the silicone elastomer on the textile support.

11. Method of preparing an article comprising a layer of silicone elastomer on a textile support according to claim 10, wherein the textile support is made of polyester or polyamide.

12. Article comprising a layer of silicone elastomer on a textile support which can be obtained by the process as described in claim 10 or claim 11.

13. Article according to claim 12, said article being an airbag.

14. Use of the silicone composition as defined in any one of claims 1 to 8 for coating textile support.

15. Use, in a silicone composition, of an adhesion-promoting system comprising: - at least one organopolysiloxane compound A having at least 2 epoxy groups and at least 3 hydrogenosilyl groups, and - at least one compound B selected from organic zinc compounds and organic iron compounds, to improve the adhesion of said silicone composition to a textile support.

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