Article suitable for food contact and method of making same

Abstract

The invention relates to an article suitable for food contact, in particular a food package, comprising a first substrate and a second substrate joined by an adhesive, said first substrate comprising a carrier coated with a silicone coating suitable for food contact, said adhesive being interposed between the two substrates and in contact with the silicone coating of said first substrate, the invention is characterized in that the adhesive is a structural silicone adhesive suitable for food contact, obtained by cross-linking a silicone composition cross-linkable by a polyaddition reaction.

Description

Technical Field

[0001] The present invention relates to the field of food packaging, and more particularly to food packaging based on silicone substrates. Background Art

[0002] Faced with changes in regulations aimed at limiting the use of single-use plastics, the industry is looking for alternatives to food packaging that typically consists of paper coated with a polyolefin coating. In this context, there is a need for solutions that provide coated paper that has water-resistant properties and is able to withstand large thermal amplitudes, particularly in the field of packaging suitable for food contact.

[0003] To meet this need, it is possible to use silicone papers, which are typically used in pastry making and are generally known as baking papers or sulphate papers. These papers are made of a material having specific porosity and roughness properties and have a thickness of about 40 g / m 2 The silicone papers are composed of a (cellulose) paper base with a grammage of 1000 g and a thin layer of silicone coated on one or both sides of the paper and having a thickness of 0.1 μm-1 μm. These silicone papers are suitable for food contact. They are anti-stick and waterproof: food does not stick to its packaging, even after a storage duration of one year or more at temperatures that can be as low as -30°C or even as low as -70°C. They can also withstand the limitations of rapid cooking technology for frozen foods (temperatures of about 300°C in microwave ovens, steam cooking) without breaking. Therefore, they are interesting candidates for the manufacture of food packaging.

[0004] For example, the manufacture of food packaging involves one or more assembly steps to produce the sides and bottom of the bag. In the case of paper coated with a polyolefin coating, these assembly steps can be performed by using an adhesive or by a welding step of the surface plastic layer.

[0005] In this case, the difficulty in manufacturing food packaging using silicone paper lies in the gluing step on the silicone side or sides.

[0006] This problem has been described, for example, in Japanese patent application JP H05-319461. This document describes the production of bags for packaging food, which are composed of silicone paper and a silicone adhesive that allows a waterproof joint to be formed. The silicone adhesive is a PSA (“pressure sensitive adhesive”) composed of silicone gel and resin.

[0007] Tests have shown that the choice of PSA as the silicone adhesive does not provide satisfactory bonding and is not suitable for food packaging.

[0008] Likewise, document KR20150057550 discloses food packaging comprising a silicone adhesive. However, this silicone adhesive is a composition crosslinkable by polycondensation releasing acetic acid. Compositions of this type are shown as comparative examples within the scope of the present invention and have the disadvantage of an unpleasant acetic acid smell for the consumer and during the gluing step. In addition, the presence of acetic acid can cause hygiene and safety problems for operators. Summary of the invention

[0009] Summary of the Invention

[0010] In this context, the present invention relates to an article suitable for food contact, in particular for food packaging, which preferably meets the following requirements: it is desirable to have an article which does not contain a polymer coating of petroleum origin, which is able to withstand large thermal amplitudes, which is waterproof, which is sealed, in particular in the assembly area, and which can be manufactured at high speed, preferably using standard industrial tools in the packaging field.

[0011] In order to meet these needs, the article suitable for food contact according to the present invention comprises a first substrate and a second substrate joined by an adhesive, the first substrate comprising a carrier coated with a silicone coating suitable for food contact, the adhesive being inserted between the two substrates and in contact with the silicone coating of the first substrate, characterized in that the adhesive is a structural silicone adhesive suitable for food contact obtained by crosslinking a silicone composition crosslinkable by a polyaddition reaction.

[0012] The present invention also relates to a method for producing an article suitable for food contact, comprising the steps of:

[0013] - providing a first substrate and a second substrate, the first substrate comprising a carrier coated with a silicone coating suitable for food contact,

[0014] - depositing a polyaddition-reaction crosslinkable silicone composition suitable for food contact on the silicone coating of the first substrate,

[0015] - assembling the second substrate with the first substrate so that the silicone composition is between the two substrates,

[0016] - causing or allowing the silicone composition to crosslink for obtaining a collage of two substrates by means of a structural silicone adhesive.

[0017] Finally, the present invention also relates to the use of a structural silicone adhesive suitable for food contact, obtained by crosslinking a silicone composition crosslinkable by a polyaddition reaction, for the production of articles suitable for food contact.

[0018] Detailed description of the invention

[0019] Unless otherwise stated, all viscosities of the silicone oils discussed in the present disclosure correspond to so-called “Newtonian” dynamic viscosity values ​​at 25° C., i.e. the dynamic viscosity measured in a manner known per se using a Brookfield viscometer at a shear rate gradient that is sufficiently low that the measured viscosity is independent of the rate gradient.

[0020] The object of the present invention is thus an article suitable for food contact comprising a first substrate and a second substrate joined by an adhesive. The adhesive is a structural silicone adhesive.

[0021] In the meaning of this document, an adhesive may be referred to as "structural" from the point where the adhesive is not a weak point of the assembly.

[0022] It is important to point out that the structural silicone adhesives defined in the present invention are not PSAs (pressure sensitive adhesives). PSAs form bonds with substrates simply by contact or by applying light pressure to engage the adhesive with the substrate surface. A physical bond is created because the PSA adhesive is soft enough to wet the surface of the substrate but hard enough to resist flow when pressure is applied to the adhesive area. When the surfaces of the adhesive and substrate are in close proximity, van der Waals type molecular interactions can contribute significantly to the bond strength. Therefore, the PSA forms a physical bond with the surface of the substrate rather than a chemical bond. A chemical bond can be defined as a bond between reactive chemical groups at the adhesive-substrate interface. In contrast, a physical bond can be defined as a temporary or reversible non-chemical bond resulting from a physical interaction between the adhesive and the substrate. Silicone PSA compositions typically consist of a hydroxylated silicone resin of the MQ(OH) type and a linear silicone rubber in solution in an organic solvent, typically toluene and / or xylene.

[0023] On the contrary, without wishing to be bound by this theory, the structural silicone adhesive according to the invention (which is not a PSA) can form chemical bonds with the substrates and can therefore ensure good adhesion between the two substrates. Preferably, the rupture between the two substrates assembled with the structural silicone adhesive according to the invention is a cohesive rupture. In this context, the expression "cohesive rupture" means a rupture that occurs in the bulk of the material, in contrast to an "adhesive rupture" which occurs at the interface between the adhesive and the substrate.

[0024] The silicone adhesive according to the invention must be suitable for food contact. In the field of food packaging, the food contactability of an object means that the materials constituting it meet regulatory or normative requirements, thus ensuring that the object does not present a risk of inducing toxicity to food or beverages.

[0025] In Europe, reference may be made in particular to Regulation (EC) 1935 / 2004, which lays down general rules for all materials intended to come into contact with foodstuffs. More particularly, the recommendations of the German BfR, or the regulation 21 CFR of the US FDA may be considered.

[0026] The materials used shall not, under normal conditions of use, release ingredients into food in amounts that could be dangerous to human health or lead to an unacceptable alteration in the composition of the food, whether or not the organoleptic properties of the food are altered.

[0027] The silicone adhesive according to the invention (which is not a PSA) is obtained by crosslinking a silicone composition crosslinkable by a polyaddition reaction. Preferably, the silicone composition crosslinkable by a polyaddition reaction comprises:

[0028] - at least one organopolysiloxane A having at least two silicon-bonded C2-C 12 Alkenyl groups,

[0029] at least one organopolysiloxane B having at least two SiH units per molecule,

[0030] - a catalytically effective amount of at least one polyaddition catalyst C, preferably a platinum-based polyaddition catalyst, and

[0031] - Optionally, at least one crosslinking inhibitor D.

[0032] Each molecule has at least two C2-C 12 The alkenyl group organopolysiloxane A may preferably be a linear organopolysiloxane formed from the following units:

[0033] - at least two siloxy units of the formula: Y a R 1 b SiO (4−a−b) / 2

[0034] in:

[0035] Y represents C2-C 12 Alkenyl, preferably vinyl; R 1represents a monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably selected from an alkyl group having 1 to 8 carbon atoms such as methyl, ethyl, propyl, a cycloalkyl group having 3 to 8 carbon atoms and an aryl group having 6 to 12 carbon atoms; a=1 or 2, b=0, 1 or 2 and the sum of a+b=2 or 3; and

[0036] - Optionally, a unit of the formula: R 1 c SiO (4−c) / 2

[0037] Where R 1 has the same meaning as above and c=2 or 3.

[0038] It should be understood that in the above formula, if there are multiple groups R 1 , then they may be the same as or different from each other.

[0039] Preferably, the organopolysiloxane A is an oil having a dynamic viscosity of 100 mPa.s to 100,000 mPa.s, preferably 1,000 mPa.s to 100,000 mPa.s. According to a preferred embodiment, the organosilicon composition according to the invention does not contain linear organosilicon silica.

[0040] Each molecule has at least two C2-C 12 The linear organopolysiloxane A of alkenyl groups may preferably be formed essentially from the following units: siloxy units "D" selected from siloxy units R 1 2SiO 2 / 2 , YR 1 SiO 2 / 2 and Y2SiO 2 / 2 and a terminal siloxy unit "M" selected from the group consisting of siloxy units YR 1 2SiO 1 / 2 、Y2R 1 SiO 1 / 2 and R 1 3SiO 1 / 2 . Symbols Y and R 1 As mentioned above.

[0041] As examples of the terminal unit "M", mention may be made of a trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy or dimethylhexenylsiloxy group.

[0042] As examples of the unit “D”, mention may be made of dimethylsiloxy, methylphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyldecenylsiloxy or methyldecadienylsiloxy groups.

[0043] Examples of linear organopolysiloxanes that may be the organopolysiloxane A according to the invention are:

[0044] - poly(dimethylsiloxane) having dimethylvinylsilyl terminal ends;

[0045] - poly(dimethylsiloxane-co-methylphenylsiloxane) having dimethylvinylsilyl terminal ends;

[0046] - poly(dimethylsiloxane-co-methylvinylsiloxane) having dimethylvinylsilyl end groups; and

[0047] - Poly(dimethylsiloxane-co-methylvinylsiloxane) having trimethylsilyl terminations.

[0048] Preferably, the organopolysiloxane A comprises terminal dimethylvinylsilyl units, and more preferably, the organopolysiloxane A is a poly(dimethylsiloxane) having dimethylvinylsilyl termini.

[0049] Preferably, the organopolysiloxane compound A has an alkenyl unit content of 0.001% to 30%, preferably 0.01% to 10%, preferably 0.02% to 5% by mass.

[0050] The silicone composition preferably comprises 50% to 95% by weight of the organopolysiloxane A, and even more preferably 60% to 90% by weight of the organopolysiloxane A.

[0051] According to one embodiment, it is possible that the organosilicon composition according to the invention contains C2-C 12 Branched organopolysiloxane or resin containing alkenyl units. Branched organopolysiloxane is also called resin, which contains siloxy units "T" (R 1 SiO 3 / 2 ) and / or siloxy units "Q" (SiO 4 / 2 ). Symbol R 1 As described above. Examples of branched organopolysiloxanes are:

[0052] - poly(dimethylsiloxane) (methylsiloxane) having trimethylsilyl and dimethylvinylsilyl terminal ends, consisting of trimethylsiloxy "M", dimethylvinylsiloxy "M", dimethylsiloxy "D" and methylsiloxy "T" units;

[0053] - a resin consisting of trimethylsiloxy "M", dimethylvinylsiloxy "M" and "Q" units; and

[0054] - Resins composed of trimethylsiloxy "M", methylvinylsiloxy "D" and "Q" units.

[0055] However, according to a preferred embodiment, the organosilicon composition does not contain C2-C 12 Branched organopolysiloxane or resin containing alkenyl units.

[0056] The organopolysiloxane B is an organopolysiloxane having at least two SiH units per molecule. It is therefore an organohydrogenpolysiloxane compound. Preferably, compound B comprises at least three SiH units.

[0057] According to a preferred embodiment, the silicone composition of the invention comprises one or more organopolysiloxanes B (in the form of a mixture).

[0058] According to a preferred embodiment, the silicone composition according to the invention comprises at least one organopolysiloxane having two SiH units per molecule and at least one organopolysiloxane having three or more SiH units per molecule.

[0059] According to one embodiment of the present invention, the organosilicon composition comprises at least one linear organopolysiloxane B having at least two SiH units per molecule, and an organopolysiloxane B having a branched structure, such as an organosilicon resin.

[0060] The organopolysiloxane B may advantageously be an organopolysiloxane comprising at least two, preferably at least three, siloxy units of the formula: d R 2 e SiO (4−d−e) / 2

[0061] Where R 2 represents a monovalent group having 1 to 12 carbon atoms, d=1 or 2, e=0, 1 or 2 and d+e=1, 2 or 3;

[0062] and optionally, other units of the formula: R 2 f SiO (4−f) / 2

[0063] Where R 2 has the same meaning as above, and f=0, 1, 2 or 3.

[0064] It should be understood that in the above formula, if there are multiple groups R 2 , then they may be the same as or different from each other.

[0065] Preferably, R 2R may represent a monovalent group selected from an alkyl group having 1 to 8 carbon atoms, which is optionally substituted by at least one halogen atom such as chlorine or fluorine; a cycloalkyl group having 3 to 8 carbon atoms; and an aryl group having 6 to 12 carbon atoms. 2 It may advantageously be selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl.

[0066] The sign d is preferably equal to 1.

[0067] The organopolysiloxane B may have a linear, branched or cyclic structure. The degree of polymerization is preferably greater than or equal to 2. Typically, it is less than 5000. Preferably, the viscosity of the organopolysiloxane B is 1 mPa.s to 5000 mPa.s, more preferably 1 mPa.s to 2000 mPa.s, even more preferably 5 mPa.s to 1000 mPa.s.

[0068] When a linear polymer is concerned, it consists essentially of units selected from 2 2SiO 2 / 2 and R 2 HSiO 2 / 2 The siloxy unit D and the unit R selected from 2 3SiO 1 / 2 and R 2 2HSiO 1 / 2 The terminal siloxy unit M is composed of 2 Has the same meaning as above.

[0069] Examples of linear organohydrogenpolysiloxanes that may be compound B according to the invention are:

[0070] - Hydrodimethylsilyl-terminated poly(dimethylsiloxane);

[0071] - poly(dimethylsiloxane-co-methylhydrogensiloxane) having trimethylsilyl terminal ends;

[0072] - poly(dimethylsiloxane-co-methylhydrogensiloxane) having hydrodimethylsilyl terminal ends;

[0073] - trimethylsilyl terminated poly(methylhydrogensiloxane); and

[0074] - Cyclic poly(methylhydrogensiloxane).

[0075] In one embodiment, the organopolysiloxane B of the silicone composition according to the present invention comprises one linear organohydrogenpolysiloxane or a plurality of linear organohydrogenpolysiloxanes as a mixture.

[0076] In one embodiment, the organopolysiloxane B of the silicone composition according to the present invention comprises an organohydrogenpolysiloxane B which is a poly(dimethylsiloxane-co-methylhydrogensiloxane) having a hydrodimethylsilyl terminal and an organohydrogenpolysiloxane B which is a poly(methylhydrogensiloxane) having a trimethylsilyl terminal.

[0077] When the organohydrogenpolysiloxane B has a branched structure, it is preferably selected from the organosilicon resins of the following formula:

[0078] - M'Q, in which the hydrogen atom bonded to the silicon atom is carried by the group M,

[0079] - MM'Q, in which the hydrogen atoms bonded to the silicon atoms are carried by part of the M unit,

[0080] - MD'Q, in which the hydrogen atom bonded to the silicon atom is carried by a group D,

[0081] - MDD'Q, in which the hydrogen atom bonded to the silicon atom is carried by part of the group D,

[0082] - MM'TQ, in which the hydrogen atoms bonded to the silicon atoms are carried by part of the M unit,

[0083] - MM'DD'Q, in which the hydrogen atoms bonded to the silicon atoms are carried by parts of the M and D units,

[0084] - and mixtures thereof,

[0085] Where M = R 2 3SiO 1 / 2 Siloxy units, M' = formula R 2 2HSiO 1 / 2 Siloxy units, D = formula R 2 2SiO 2 / 2 Siloxy units, D' = formula R 2 HSiO 2 / 2 Siloxy units, T = formula R 2 3SiO 1 / 2 Siloxy units and Q = SiO 4 / 2 The siloxy units, where R 2 Has the same meaning as above.

[0086] In one embodiment, the organopolysiloxane B of the silicone composition according to the present invention comprises one or more linear organohydrogenpolysiloxanes (in the form of a mixture), and a silicone resin.

[0087] In one embodiment, the organopolysiloxane B of the silicone composition according to the present invention comprises an organohydrogenpolysiloxane B which is a poly(dimethylsiloxane-co-methylhydrogensiloxane) having a hydrogendimethylsilyl terminal, an organohydrogenpolysiloxane B which is a poly(methylhydrogensiloxane) having a trimethylsilyl terminal, and a silicone resin.

[0088] Preferably, the organopolysiloxane B has a mass content of hydrosilyl functional groups Si—H of 0.2% to 91%, more preferably 3% to 80%, even more preferably 15% to 70%.

[0089] Advantageously, the molar ratio of hydrosilyl functional groups Si—H of organopolysiloxane B to olefin functional groups of organopolysiloxane A is between 0.01 and 20, preferably between 0.1 and 10, preferably between 0.5 and 5, more preferably between 1 and 5, even more preferably between 1 and 3.

[0090] The silicone composition according to the present invention preferably comprises 0.1% to 20% by weight of the organopolysiloxane B, more preferably 0.1% to 10% by weight, even more preferably 0.5% to 5% by weight.

[0091] The hydrosilylation catalyst C may be chosen in particular from compounds of platinum and rhodium, but may also be chosen from silicon compounds, such as those described in patent applications WO2015 / 004396 and WO2015 / 004397; germanium compounds, such as those described in patent application WO20160 / 75414; or complexes of nickel, cobalt or iron, such as those described in patent applications WO2016 / 071651, WO2016 / 071652 and WO2016 / 071654. Catalyst C 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 organic products described in US Pat. Nos. 3,159,601, 3,159,602, 3,220,972 and EP Pat. Nos. 0.057.459, 0.188.978 and 0.190.530, or complexes of platinum and vinylated organosiloxanes described in US Pat. Nos. 3,419,593, 3,715,334, 3,377,432 and 3,814,730 may be used. Alternatively, photoactivatable hydrosilylation catalysts may be used. The catalysts may be activated by irradiation, in particular by UV radiation.

[0092] Preferably, catalyst C is a compound derived from platinum. In this case, the weight amount of catalyst C calculated as the weight of platinum metal is generally 2 ppm to 400 ppm by mass, more preferably 50 ppm to 300 ppm by mass, and even more preferably 70 ppm to 200 ppm, based on the total weight of the organosilicon composition. Alternatively, the weight amount of catalyst C calculated as the weight of platinum metal may be 5 ppm to 200 ppm by mass, more preferably 20 ppm to 200 ppm.

[0093] Preferably, catalyst C is a Karstedt platinum catalyst.

[0094] The silicone composition according to the present invention may optionally contain a crosslinking inhibitor D. The crosslinking inhibitor is designed to slow down the crosslinking reaction and is also called a retarder. Crosslinking inhibitors are well known in the prior art. For example, cyclic polymethylvinylsiloxanes and acetylene alcohols described in US Pat. No. 3,923,705, acetylene alcohols described in US Pat. No. 3,445,420, heterocyclic amines described in US Pat. No. 3,188,299, diallyl maleate and other dialkyl esters described in US Pat. No. 4,256,870, olefinic siloxanes described in US Pat. No. 3,989,667, and dialkyl acetylene dicarboxylates described in US Pat. No. 4,347,346 can be mentioned. Mention may also be made of the following classes of inhibitors: hydrazines, triazoles, phosphines, thiols, organic nitrogen-containing compounds, acetylenic alcohols, silylated acetylenic alcohols, maleates, fumarates, aromatic or ethylenically unsaturated amides, ethylenically unsaturated isocyanates, ethylenic siloxanes, unsaturated hydrocarbon monoesters and diesters, conjugated ene-ynes, hydroperoxides, nitriles and diaziridines. The crosslinking inhibitor D is preferably selected from the group consisting of 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-pentene-4-yn-3-ol, 3-methyl-1-dodecyn-3-ol, 3,7,11-trimethyl-1-dodecyn-3-ol, 1,1-diphenyl-2-propyn-1-ol, 3,6-diethyl-1-nonyn-3-ol, 3-methyl-1-pentadecin-3-ol and mixtures thereof. Acetylenic alcohols are very preferred crosslinking inhibitors D according to the invention, and very particularly 1-ethynyl-1-cyclohexanol (ECH). According to one embodiment, the silicone composition D comprises 1 ppm to 1000 ppm, preferably 20 ppm to 500 ppm, of crosslinking inhibitor D, relative to the total weight of the silicone composition.

[0095] The silicone composition crosslinkable by polyaddition reaction may optionally contain a filler. According to one embodiment, the silicone composition contains 5% to 40% by weight of filler relative to the total weight of the silicone composition. Advantageously, the silicone composition contains 10% to 30% by weight of filler.

[0096] The fillers which are optionally provided are preferably mineral. The fillers may be very finely divided products, the average particle size of which is less than 0.1 µm. The fillers may in particular be siliceous. In the case of siliceous materials, they may function as reinforcing or semi-reinforcing fillers. Reinforcing siliceous fillers are selected from powders of colloidal silica, fumed silica and precipitated silica or mixtures thereof. These powders generally have an average particle size of less than 0.1 µm (micrometer) and a BET specific surface area of ​​more than 30 m 2 / g, preferably 30m 2 / g -350m 2 / g. Semi-reinforced siliceous fillers can also be used, such as diatomaceous earth or ground quartz. These silicon dioxides can be added as is or added after being treated with the organic silicon-containing compound that is generally used for this purpose. Among these compounds, methylpolysiloxanes such as hexamethyldisiloxane, octamethylcyclotetrasiloxane, methylpolysilazane such as hexamethyldisilazane, hexamethylcyclotrisilazane, tetramethyldivinyldisilazane, chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, dimethylvinylchlorosilane, alkoxysilanes such as dimethyldimethoxysilane, dimethylvinylethoxysilane, trimethylmethoxysilane, and mixtures thereof can be mentioned. About non-siliceous mineral materials, they can be used as semi-reinforced or filled mineral fillers. Examples of these non-siliceous fillers, which can be used alone or in a mixture, are calcium carbonate, optionally surface-treated with an organic acid or ester of an organic acid, calcined clay, rutile titanium dioxide, oxides of iron, zinc, chromium, zirconium or magnesium, various forms of alumina (hydrated or non-hydrated), boron nitride, lithopone, barium metaborate, barium sulfate and glass microspheres. These fillers are relatively coarse, usually having an average particle size of more than 0.1 µm and a specific surface area of ​​less than 30 m 2 These fillers may have been surface-modified with various organic silicon-containing compounds commonly used for this purpose.

[0097] Preferably, the filler is silica, even more preferably fumed silica. Advantageously, the silica has a 2 / g-410m 2 / g BET specific surface area.

[0098] The silicone composition according to the invention may also contain other functional additives commonly found in silicone compositions. As categories of common functional additives, mention may be made of: adhesion promoters, adhesion regulators, additives for increasing consistency, additives for heat resistance, oil resistance or flame retardancy such as metal oxides, virucides, bactericides, anti-wear additives and pigments (organic or mineral).

[0099] However, some common additives in silicone compositions are incompatible with use for food contact. It is therefore preferred that the silicone composition does not contain any additional additives.

[0100] Typically, the adhesion promoting compound may be an organic silicon-containing compound comprising an adhesion promoting functional group. In particular, it may be an organic silicon-containing compound comprising:

[0101] - one or more hydrolyzable groups bonded to a silicon atom, typically an alkoxy group bonded to a silicon atom, and

[0102] - one or more organic groups selected from the group consisting of thiol, urea, isocyanurate, (meth)acrylate, epoxy and alkenyl groups.

[0103] By way of example, the following compounds may be mentioned, used alone or in mixtures: vinyltrimethoxysilane (VTMO), 3-glycidyloxypropyltrimethoxysilane (GLYMO), methacryloxypropyltrimethoxysilane (MEMO), [H2N(CH2)3]Si(OCH2CH2CH3)3, [H2N(CH2)3]Si(OCH3)3, [H2N(CH2)3]Si(OC2H5)3, [H2N(CH2)4]Si(OCH3)3, [H2NCH2CH(CH3)CH2CH2]SiCH3(OCH3)2, [H2NCH2]Si(OCH3)3, [n- C4H9-HN-CH2]Si(OCH3)3, [H2N(CH2)2NH(CH2)3]Si(OCH3)3, H2N(CH2)2NH(CH2)3]Si(OCH2CH2OCH3)3, [CH3NH(CH2)2NH(CH2)3]Si(OCH3)3, [H(NHCH2CH2)2NH(CH2)3]Si(OCH3)3, HS(CH2)3Si(OCH3)3, NH2CONH2(CH2)3Si(OCH3), or polyorganosiloxane oligomers, containing, for example, 2 to 100 silicon atoms, containing such organic groups in a content of more than 20%. Mention may also be made of organic silicon-containing compounds containing at least one, preferably at least two, alkoxy groups bonded to silicon atoms and at least one epoxy group.

[0104] Furthermore, the adhesion promoting compound may be an organic titanium compound, preferably a titanium chelate or a metal alkoxide of the formula Ti(OR)4, wherein R is selected from a linear or branched C1-C8 alkyl, alkoxyalkyl, or acyl group. Even more preferably, the organic titanium compound is selected from titanium alkylates, such as butyl titanate, isopropyl titanate, methyl titanate, and octyl titanate. Even more preferably, the organic titanium compound is butyl titanate (TBOT).

[0105] According to a preferred embodiment, the silicone composition according to the invention comprises no adhesion-promoting compounds. In particular, the silicone composition according to the invention preferably does not comprise any of the adhesion-promoting compounds mentioned individually above.

[0106] Furthermore, the silicone composition according to the invention preferably contains no organic solvents, typically no toluene or xylene.

[0107] According to a preferred embodiment, the silicone composition crosslinkable by a polyaddition reaction according to the invention comprises, based on the total weight of the silicone composition:

[0108] - 50% to 95%, preferably 60% to 90%, of an organopolysiloxane A having at least two silicon-bonded C2-C 12 Alkenyl groups,

[0109] - 0.1% to 20%, preferably 0.5% to 5%, of an organopolysiloxane B having at least two SiH units per molecule,

[0110] - 1 ppm to 400 ppm, preferably 2 ppm to 200 ppm, of a hydrosilylation catalyst C (calculated as metal weight),

[0111] - optionally, 1 ppm to 1000 ppm, preferably 20 ppm to 500 ppm, of a crosslinking inhibitor D,

[0112] - Optionally, 5% to 40%, preferably 10% to 30%, of silica filler.

[0113] According to one particular embodiment, the silicone composition crosslinkable by a polyaddition reaction according to the invention comprises, based on the total weight of the silicone composition:

[0114] - 50% to 95%, preferably 60% to 90%, of an organopolysiloxane A having at least two silicon-bonded C2-C 12 Alkenyl groups,

[0115] - 0.1% to 20%, preferably 0.5% to 5%, of an organopolysiloxane B having at least two SiH units per molecule, and an organopolysiloxane B having a branched structure, such as an organosilicon resin,

[0116] - 1 ppm to 400 ppm, preferably 2 ppm to 200 ppm, of a hydrosilylation catalyst C (calculated as metal weight),

[0117] - optionally, 1 ppm to 1000 ppm, preferably 20 ppm to 500 ppm, of a crosslinking inhibitor D,

[0118] - Optionally, 5% to 40%, preferably 10% to 30%, of silica filler.

[0119] The silicone composition crosslinkable by polyaddition reaction according to the present invention preferably has a viscosity greater than 5000 mPa·s, more preferably 10000 mPa·s to 100000 mPa·s.

[0120] According to one embodiment, the silicone composition according to the invention can be prepared from a two-component system, characterized in that it is in two separate parts that are intended to be mixed to form the silicone composition, and one of the parts contains the catalyst C and no organopolysiloxane B, while the other part contains the organopolysiloxane B and no catalyst C.

[0121] The silicone composition can be prepared by mixing all the different components as described above. The mixing can be carried out under an inert gas atmosphere using a mixer suitable for such compositions, such as a kneader or a planetary mixer. Alternatively, the two parts of the composition can be stored in a two-component adhesive cartridge, the mixing being ensured at the outlet of the cartridge by a static mixer.

[0122] After crosslinking, the silicone composition according to the invention forms a structural silicone adhesive which enables the assembly of a plurality of substrates.

[0123] The article suitable for food contact according to the present invention comprises a first substrate and a second substrate, which are joined by an adhesive as described above. The first substrate comprises a carrier coated with a silicone coating suitable for food contact.

[0124] The support is preferably a fibrous support. Among the fibrous supports, mention may be made of various papers (e.g. kraft paper with any degree of refinement, glassine, sulphate paper), cardboard, vegetable parchment, paper coated with polyethylene or carboxymethylcellulose, cellulose sheets. Very preferably, the support is selected from paper and cartons. In the case of a paper support, a paper may be chosen which preferably has a Bendtsen porosity of 0.1 mL / min to 500 mL / min according to ISO 5636-3 standard and a COBB value of water of 5-30 according to ISO 535 method.

[0125] Alternatively, the carrier may be a polymeric material, such as a sheet of polymeric material, such as those made of polyethylene, polypropylene, polyethylene terephthalate, polyester or a natural polymer.

[0126] Alternatively still, the carrier may be made of metal, such as a metal sheet.

[0127] According to one embodiment, the carrier according to the invention is a flexible carrier. In this context, the term "flexible carrier" refers to a carrier that can be bent or folded by human effort alone without breaking or being damaged. In contrast, according to another embodiment, the carrier according to the invention is a rigid or semi-rigid carrier, in this context, the term "rigid or semi-rigid carrier" refers to a carrier that cannot be easily bent or folded by human effort alone without breaking or being damaged.

[0128] Preferably, the carrier is in the form of a sheet or a film. However, any other form is possible within the scope of the present invention.

[0129] According to the present invention, the carrier of the first substrate is coated with a silicone coating suitable for food contact. The silicone coating may be present on one side of the carrier or on both sides. Such coatings are known to those skilled in the art. Typically, the silicone coating suitable for food contact can be obtained by coating the carrier with a silicone composition and then crosslinking it. The silicone composition may be a silicone emulsion or a solvent-free silicone composition. For silicone emulsions, reference may be made in particular to European patent application EP 0253747 and international applications WO 99 / 35181 and WO 2018 / 178321. For solvent-free silicone compositions, reference may be made, for example, to international application WO 2005 / 059039.

[0130] Preferably, suitable silicone coatings consist of a waterproof and anti-stick coating or film obtained by coating a support with a silicone emulsion and then crosslinking it. The silicone emulsion can be crosslinked by polycondensation chemistry or by polyaddition chemistry. Preferably, the silicone emulsion is an aqueous silicone emulsion that can be crosslinked by polyaddition reaction to obtain a silicone elastomer. Generally, polyaddition chemistry is preferred for reasons of suitability for food contact, since certain tin-based polycondensation catalysts cannot be used. Furthermore, without wishing to be bound by this theory, it is believed that silicone coatings obtained by polyaddition reactions can have residual chemical functional groups on the surface, which can potentially be used as anchoring points for structural silicone adhesives involving the same crosslinking chemistry.

[0131] It can be an aqueous silicone emulsion that can be crosslinked by a polyaddition reaction to obtain a silicone elastomer, the aqueous silicone emulsion comprising:

[0132] at least one organopolysiloxane having per molecule at least two unsaturated functional groups of the C2-C6 alkenyl type bonded to silicon,

[0133] - at least one organopolysiloxane having at least three silicon-bonded hydrogen atoms per molecule,

[0134] - at least one polyaddition catalyst,

[0135] - at least one emulsifier,

[0136] -water,

[0137] - optionally, at least one cross-linking inhibitor,

[0138] - optionally, at least one pH fixing agent, which is chosen so as to maintain the pH of the emulsion between 5 and 9, preferably between 5.5 and 8.5, even more preferably between 6 and 8,

[0139] - Optionally, at least one formulation additive, for example a bactericide such as sorbic acid, an antifreeze and / or wetting agent, for example a glycol such as propylene glycol or ethylene glycol, an antifoaming agent, a filler, preferably a mineral filler, selected from siliceous or non-siliceous materials, more particularly preferably a siliceous filler, a colorant or pigment, an acidulant such as acetic acid.

[0140] However, some common additives in silicone compositions are incompatible with use for food contact. It is therefore preferred that the silicone composition does not contain any additional additives.

[0141] The production of the support, in particular silicone paper, coated with the silicone coating according to the invention can typically be carried out by in-line coating, that is to say directly on the machine for producing the support, once the sheet has been formed.

[0142] The silicone coating preferably has a 0.05 g / m2 -1g / m 2 However, the amount of silicone emulsion applied to the carrier should be adjusted taking into account the penetration of silicone in the carrier. For example, if the penetration of silicone in the carrier is 0%-50% and the paper is coated on both sides, 2 The total amount of silicone in the paper is preferably 0.1 g / m 2 -4g / m 2 .

[0143] According to a first embodiment, the second substrate according to the invention is identical to the first substrate. For example, the first substrate and the second substrate may be a single silicone sheet folded upon itself. Thus, the second substrate comprises a carrier coated with a silicone coating suitable for food contact. The carrier and the silicone coating may be as previously described for the first substrate. In this configuration, the structural silicone adhesive is preferably inserted between the two substrates and in contact with the silicone coatings of the two substrates.

[0144] According to a second embodiment, the second substrate according to the invention is different from the first substrate. The second substrate may be a carrier as described above without a silicone coating. For example, the second substrate may be a transparent sheet of polymer material. In this configuration, the structural silicone adhesive is preferably inserted between the two substrates and in contact with the silicone coating of the first substrate, the second substrate not necessarily having a silicone coating.

[0145] The article suitable for food contact according to the present invention can be obtained by a process comprising the following steps:

[0146] - providing a first substrate and a second substrate, the first substrate comprising a carrier coated with a silicone coating suitable for food contact,

[0147] - depositing a polyaddition-reaction crosslinkable silicone composition suitable for food contact on the silicone coating of the first substrate,

[0148] - assembling the second substrate with the first substrate so that the silicone composition is between the two substrates,

[0149] - causing or allowing the silicone composition to crosslink for obtaining bonding of two substrates by means of a structural silicone adhesive.

[0150] The silicone composition suitable for food contact which is crosslinkable by a polyaddition reaction can be deposited on the first substrate according to methods known to those skilled in the art. The deposition can generally be carried out by pouring, brushing, knife coating, dipping or extrusion. According to one embodiment, the deposition of the silicone composition is carried out continuously on a portion of the silicone coating of the first substrate. Thus, the silicone coating of the first substrate is covered, for example, with a strip of the silicone composition. This embodiment is advantageous if it is desired to obtain a continuous and sealed gluing between the first and second substrates.

[0151] However, within the scope of the invention, it is also possible to deposit the silicone composition only on certain areas or discontinuously, for example in the form of spots, when no sealing gluing is sought.

[0152] The amount of the silicone composition deposited on the silicone coating of the first substrate may be 1 g / m 2 -50g / m 2 , preferably 5g / m 2 -20g / m 2 .

[0153] Prior to depositing the polyaddition-crosslinkable silicone composition, the method may include the optional step of surface treating the silicone coating of the first substrate, such as by corona treatment.

[0154] The assembly of the second substrate to the first substrate can be carried out continuously with the aid of a roller and a contact blade.

[0155] If the reactivity between the previously contacted parts is sufficient, the silicone composition can crosslink without external intervention. However, thermal activation of the crosslinking reaction is preferred. The means for thermally activated crosslinking are generally an oven (e.g. a tunnel oven), heated lamination rollers or an infrared source. This thermal activation can be supplemented by photochemical activation and / or by electron bombardment. The crosslinking temperature may be greater than 120° C., without exceeding the degradation temperature of the support, and is preferably between 160° C. and 200° C. The duration of the thermal activation step of the crosslinking may be from 0.1 s to 30 s, preferably from 0.1 s to 5 s.

[0156] Alternatively, the crosslinking reaction can be activated by irradiation, for example by UV activation. To this end, the person skilled in the art can select a photoactivatable polyaddition catalyst and optionally a suitable photosensitizing additive.

[0157] Advantageously, the steps for manufacturing the article suitable for food contact as described above can be carried out continuously using equipment known to a person skilled in the art, in particular using a machine for manufacturing packaging.

[0158] After crosslinking, the final thickness of the structural silicone adhesive may be between 1 μm and 50 μm, preferably between 5 μm and 20 μm.

[0159] The article suitable for food contact according to the invention may advantageously be a food packaging. It may be chosen, for example, from:

[0160] - Flexible packaging: bags (sacs), Pochettes and Pochons, in particular for sealed packaging, with the optional presence of a vent valve, bags for sandwiches, bags with or without transparent windows, Bloomer bags, etc.,

[0161] - Semi-rigid packaging: boxes (boites), lunch boxes, pastry boxes, hamburger boxes, crates (étui), cones (cônes), boats (barquettes), pots with or without lids, flat-bottomed cups (gobelets), shells (coquilles), Berlingots boxes, Briques boxes, etc.,

[0162] - Rigid packaging: corrugated cardboard boxes (pizza box type).

[0163] The articles according to the invention have properties which make them particularly advantageous both for food packaging professionals and for the final consumer:

[0164] -It is suitable for food contact, in compliance with current regulatory requirements. Silicones are known to be non-toxic and inert to food when they are correctly formulated and used. In addition, thanks to the use of polyaddition silicone adhesives, the product does not contain tin-based catalysts.

[0165] - Thanks to the silicone coating and the silicone adhesive, the article is able to withstand large thermal ranges, typically from -30°C to +250°C or from -70°C to +250°C. The article can be used both for freezing and for cooking. It is particularly suitable for microwave cooking. The article has water-blocking properties. It is also non-stick and waterproof: the food does not stick to its packaging even after storage.

[0166] - The choice of the structural silicone adhesive enables cohesive and permanent assembly of the substrates. Thus a sealed assembly can be produced which can be used for long-term food preservation.

[0167] - Finally, from an implementation point of view, the manufacture of the article suitable for food contact according to the invention can be carried out at high speed, preferably using standard industrial tools in the packaging field. The crosslinking speed of the adhesive is compatible with the high speeds of industry. The viscosity of the adhesive is also compatible with industrial deposition tools. Finally, the crosslinking of the adhesive occurs without releasing any odor.

[0168] The present invention also relates to the use of a structural silicone adhesive suitable for food contact, obtained by crosslinking a silicone composition crosslinkable by a polyaddition reaction, for the production of articles suitable for food contact. DETAILED DESCRIPTION

[0169] Further details or advantages of the invention will emerge more clearly from the following examples which are given by way of indication only. Example

[0170] Manual coating test

[0171] A silicone baking paper of A5 format was manually coated with the silicone composition. A second baking paper identical to the first was manually applied to the coating and the assembly was crosslinked as detailed below.

[0172] The silicone compositions tested are as follows:

[0173] PSA 1: Silicone PSA, composed of polydimethylsiloxane gum and MQ(OH) hydroxylated resin (in toluene). Dry matter content: 60%. Viscosity: 80000mPa.s

[0174] PSA 2: Silicone PSA, composed of polydimethylsiloxane gum and MQ(OH) hydroxylated resin (in toluene). Dry matter content: 60%. Viscosity: 70000mPa.s

[0175] Adhesive 1: RTV2 type silicone composition, in 2 parts, crosslinked by polyaddition.

[0176] Part A:

[0177] For 100 copies:

[0178] - 74.38 parts of polydimethylsiloxane oil with Si(CH3)2CH=CH2 terminal ends and a viscosity of 1500 mPa.s

[0179] - 2.11 parts of organopolysiloxane oil B, consisting of polydimethylsiloxane oil with Si(CH3)2H terminal and polymethylhydrogensiloxane oil with Si(CH3)3 terminal

[0180] - 23.48 parts of treated fumed silica, 1

[0181] - 0.03 parts of ethynyl-1-cyclohexanol (ECH).

[0182] Part B:

[0183] For 100 copies:

[0184] - 99 parts of polydimethylsiloxane oil with Si(CH3)2CH=CH2 terminal, viscosity 100000 mPa.s,

[0185] - 1 part of Karstedt's platinum catalyst (10 ppm relative to the total weight of the composition). Part A and Part B are mixed so as to obtain a mass ratio of Part A relative to Part B equal to 10.

[0186] Viscosity of adhesive 1: 40000 mPa.s.

[0187] Adhesive 2 (Variant 3): Silicone composition of the RTV2 type, in 2 parts, crosslinked by polyaddition.

[0188] Part A:

[0189] For 100 copies:

[0190] - 75.04 parts of polydimethylsiloxane oil with Si(CH3)2CH=CH2 terminal ends and a viscosity of 1500 mPa.s

[0191] - 1.25 parts of organopolysiloxane oil B, composed of a resin of MM'Q type (in which the hydrogen atoms bonded to the silicon atoms are carried by the group M), a polymethylhydrogensiloxane oil with Si(CH3)3 terminals and a poly(dimethylsiloxane-co-methylhydrogensiloxane) with Si(CH3)2H terminals,

[0192] - 23.68 parts of treated fumed silica,

[0193] - 0.03 parts of 1-ethynyl-1-cyclohexanol (ECH).

[0194] Part B:

[0195] - 99 parts of polydimethylsiloxane oil with Si(CH3)2CH=CH2 terminal, viscosity 100000 mPa.s,

[0196] - 1 part of Karstedt platinum catalyst (10 ppm relative to the total weight of the composition). Part A and Part B are mixed so as to obtain a mass ratio of Part A relative to Part B equal to 10.

[0197] Viscosity of adhesive 2: 40000 mPa.s.

[0198] Adhesive 3 (Variant 7): Silicone composition of the RTV2 type, in 2 parts, crosslinked by polyaddition.

[0199] Part A:

[0200] For 100 copies:

[0201] - 75.06 parts of polydimethylsiloxane oil with Si(CH3)2CH=CH2 terminal ends and a viscosity of 1500 mPa.s

[0202] - 1.22 parts of organopolysiloxane oil B, consisting of polymethylhydrogensiloxane oil with Si(CH3)3 terminals and poly(dimethylsiloxane-co-methylhydrogensiloxane) with Si(CH3)2H terminals,

[0203] - 23.69 parts of treated fumed silica,

[0204] - 0.03 parts of 1-ethynyl-1-cyclohexanol (ECH).

[0205] Part B:

[0206] For 100 copies:

[0207] - 99 parts of polydimethylsiloxane oil with Si(CH3)2CH=CH2 terminal, viscosity 100000 mPa.s,

[0208] - 1 part of Karstedt platinum catalyst (10 ppm relative to the total weight of the composition).

[0209] Part A and part B are mixed so as to obtain a mass ratio of part A relative to part B equal to 10.

[0210] Viscosity of adhesive 3: 40000 mPa.s.

[0211] Adhesive 4 (comparative): RTV2 type silicone composition, in 2 parts, crosslinked by polyaddition.

[0212] Part A: polydimethylsiloxane oil with Si(CH3)2CH=CH2 terminal ends, polydimethylsiloxane oil with Si(CH3)2H terminal ends and poly(methylhydrogensiloxane-co-dimethylsiloxane) with Si(CH3)3 terminal ends, treated fumed silica, 1-ethynyl-1-cyclohexanol (ECH), 3-glycidyloxypropyltrimethoxysilane (GLYMO).

[0213] Part B: polydimethylsiloxane oil with Si(CH3)2CH=CH2 terminal ends, treated fumed silica, Karstedt platinum catalyst (10 ppm relative to the total weight of the composition), butyl titanate (TBOT).

[0214] Part A and part B are mixed so as to obtain a mass ratio of part A relative to part B equal to 10. Viscosity of adhesive 4: 40000 mPa.s.

[0215] Such compositions are not suitable for food contact due to the presence of adhesion promoters such as 3-glycidyloxypropyltrimethoxysilane (GLYMO) or tetrabutyl titanate (TBOT).

[0216] Adhesive 5 (comparative): Silicone composition of RTV1 type, in 1 part, crosslinked by polycondensation.

[0217] Formulation: Hydroxyl-terminated polydimethylsiloxane oil, treated fumed silica, methyltriacetoxysilane, tetra-n-butyl titanate (condensation catalyst).

[0218] The quality of the bond is evaluated on a dynamometer using the T-peel method inspired by the ASTM D 1876 standard. Particular attention is paid to the fracture mode of the specimen, which must be cohesive (tearing of the paper during the test) to ensure optimal performance of the assembly.

[0219] The results are reported in Table 1 below:

[0220] The results obtained with PSA-type compositions are inconclusive and clearly inferior to those of structural adhesives. The inventive adhesives 1, 2 and 3, each of which is a silicone composition crosslinked by polyaddition, make it possible to obtain satisfactory adhesion while being suitable for food contact and without major disadvantages in terms of formability (e.g. odor).

[0221] Unlike the comparative example (adhesive 4), the adhesives of the invention (1, 2 and 3) do not require the presence of an adhesion promoter to obtain satisfactory bonding results. Moreover, comparative example 5 is an adhesive which crosslinks by polycondensation and therefore has the disadvantage of releasing acetic acid.

[0222] Furthermore, the inventive adhesives 2 and 3 give satisfactory results despite the low adhesive thicknesses applied. These embodiments are therefore particularly advantageous on an industrial scale.

[0223] Coating test using roller

[0224] A coating tool with two rollers and a heated doctor blade is used. The tool is as Figure 1 Shown: The first substrate (1) and the second substrate (2) are fixed on rollers. The adhesive composition is applied by a deposition device (3). A heated metal scraper (4) is brought into contact with the second carrier before the assembly passes between 2 heated metal laminating rollers (5). The gap (6) between the 2 rollers is fixed at 0.1 mm. The travel in the tool is manual and is estimated to be about 10 m / min. The set temperature of the scraper and the 2 metal rollers is regulated electronically.

[0225] Substrate: Commercial baking paper coated with silicone

[0226] The composition of the silicone adhesive is as described above for Adhesive 1.

[0227] The evaluation of the crosslinking is visual and is carried out by means of a scissors blade encrassement test: just after the crosslinking, a cutting test is carried out with a paper knife or scissors to assess the encrassement of the blade. The blade of the cutting tool should not be encrassed and should be kept free of silicone.

[0228] Manual evaluation of adhesion: Just after crosslinking, the two parts of the assembly are firmly held during a shear test. The assembly must be able to withstand the stresses applied by the production tool.

[0229] The results are shown in Table 2 below:

[0230] [Table 2]

[0231] The assemblies obtained as described above were placed in a cold environment (-17°C) in a food freezer for 2 hours, then removed and immediately subjected to mechanical testing. Other assemblies were placed in a hot environment (+230°C) in a laboratory oven for 2 hours, then removed and immediately subjected to mechanical testing. In both cases, a preservation of the mechanical properties of the assemblies was observed.

Claims

1. An article suitable for food contact, comprising a first substrate and a second substrate joined by an adhesive, wherein the first substrate comprises a carrier coated with a silicone coating suitable for food contact, the adhesive is inserted between the two substrates and in contact with the silicone coating of the first substrate, characterized in that The adhesive is a structural silicone adhesive suitable for food contact obtained by crosslinking a silicone composition crosslinkable by a polyaddition reaction.

2. The article according to claim 1, characterized in that The silicone composition crosslinkable by polyaddition reaction comprises: - at least one organopolysiloxane A having at least two silicon-bonded C2-C 12 Alkenyl groups, - at least one organopolysiloxane B having at least two SiH units per molecule, - a catalytically effective amount of at least one polyaddition catalyst C, preferably a platinum-based polyaddition catalyst, and - Optionally, at least one crosslinking inhibitor D.

3. The product according to claim 1 or claim 2, characterized in that The silicone composition crosslinkable by polyaddition reaction comprises 5% to 40% by weight of filler relative to the total weight of the silicone composition.

4. The product according to any one of claims 1 to 3, characterized in that The silicone composition contains no organic solvents, typically no toluene or xylene.

5. The product according to any one of claims 1 to 4, characterized in that The silicone composition crosslinkable by polyaddition reaction has a viscosity greater than 5000 mPa·s, more preferably 10000 mPa·s to 100000 mPa·s.

6. The product according to any one of claims 1 to 5, characterized in that The support is a fibrous support, preferably, the support is selected from paper and paperboard.

7. The product according to any one of claims 1 to 6, characterized in that The silicone coating suitable for food contact consists of a waterproof and non-stick coating or film obtained by coating a support with a silicone emulsion, preferably an aqueous silicone emulsion which can be crosslinked by a polyaddition reaction to give a silicone elastomer, and then crosslinking it.

8. The product according to any one of claims 1 to 7, characterized in that The article is a food packaging, preferably selected from: - Flexible packaging: bags, Pochettes and Pochons, in particular for sealed packaging, with the optional presence of a vent valve, bags for sandwiches, bags with or without transparent windows, Bloomer bags, etc., - Semi-rigid packaging: boxes, lunch boxes, pastry boxes, hamburger boxes, crates, cones, boats, pots with or without lids, tumblers, shells, Berlingots, Briques, etc., - Rigid packaging: corrugated cardboard boxes (pizza box type).

9. A method for producing an article suitable for food contact, the method comprising the steps of: - providing a first substrate and a second substrate, the first substrate comprising a carrier coated with a silicone coating suitable for food contact, - depositing a polyaddition-reaction crosslinkable silicone composition suitable for food contact on the silicone coating of the first substrate, - assembling the second substrate with the first substrate so that the silicone composition is between the two substrates, - causing or allowing the silicone composition to crosslink for obtaining bonding of two substrates by means of a structural silicone adhesive.

10. Use of a structural silicone adhesive suitable for food contact obtained by crosslinking a silicone composition crosslinkable by a polyaddition reaction for the production of articles suitable for food contact.

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