Articles suitable for contact with food and their manufacturing methods

Abstract

The present invention relates to an article suitable for contact with food, in particular food packaging, comprising a first substrate and a second substrate joined by an adhesive, the first substrate comprising a support coated with a silicone coating suitable for contact with food, the adhesive being interposed between the two substrates and in contact with the silicone coating of the first substrate, the adhesive being a structural silicone adhesive suitable for contact with food, characterised in that the adhesive is obtained by crosslinking a silicone composition crosslinkable by polyaddition reaction.

Description

[Technical field]

[0001] The present invention relates to the field of food packaging, and more specifically to silicone-based food packaging. [Background technology]

[0002] Prior Art Faced with regulatory changes aimed at limiting the use of single-use plastics, the industry is looking for alternatives for food packaging, which generally consists of paper coated with a polyolefin coating. In this context, there is a demand, especially in the field of packaging suitable for contact with food, to propose coated paper solutions that are water-resistant and able to withstand a large temperature range.

[0003] To meet this demand, it is envisaged to use silicone papers, commonly used in pastry and commonly called baking parchment or greaseproof paper. These papers have specific porosity and roughness characteristics and have a weight of about 40 g / m 2 It consists of a (cellulose-based) paper substrate with a basis weight of 100 g / m² and a thin layer of silicone with a thickness of 0.1 μm to 1 μm, coated on one or both sides of the paper. These silicone papers are suitable for contact with food. They are non-stick and water-repellent. Food does not stick to the packaging even when stored at temperatures as low as -30°C or -70°C for more than a year. They can also withstand the stresses of rapid cooking techniques for frozen foods (microwave oven at about 300°C, steam cooking) without decomposing. They are therefore good candidates for the manufacture of food packaging. The manufacture of food packaging involves one or more assembly steps, for example to produce the sides and bottom of the bag. In the case of papers coated with polyolefin coatings, these assembly steps can be performed using adhesives or by fusing a surface plastic layer. In this context, one of the difficulties with using silicone paper in the manufacture of food packaging is the process of applying an adhesive to the silicone surface.

[0004] This problem is described, for example, in JP-A-5-319461. This specification describes a method for manufacturing food packaging bags that are made of silicone paper and silicone adhesive and can be sealed without leaks. The silicone adhesive is a PSA (pressure sensitive adhesive) made of silicone rubber and resin.

[0005] Test results showed that the silicone adhesive selected as PSA did not provide satisfactory adhesion and was not suitable for food packaging.

[0006] Similarly, Korean Patent Application Publication No. 20150057550 describes a food packaging containing a silicone adhesive. However, this silicone adhesive is a composition that can be crosslinked by polycondensation and releases acetic acid. This type of composition is exemplified as a comparative example in the present invention, and has the disadvantage of unpleasant acetic acid odor for consumers and during the adhesive bonding process. Furthermore, the presence of acetic acid may cause health and safety concerns for operators. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 5-319461 [Patent Document 2] Korean Patent Application Publication No. 20150057550 Summary of the Invention [Problem to be solved by the invention]

[0008] In this context, a subject of the present invention is an article suitable for contact with food, in particular food packaging, which preferably fulfils the following requirements: it is desirable to obtain an article that is free of petroleum-based polymer coatings, is able to withstand a large temperature range, is water-tight, is leak-free, in particular in the assembly area, and can be produced with high throughput, preferably using standard industrial equipment in the packaging sector. [Means for solving the problem]

[0009] In order to meet these demands, the present invention provides an article suitable for contact with food, comprising a first substrate and a second substrate joined by an adhesive, the first substrate comprising a support coated with a silicone coating suitable for contact with food, the adhesive being interposed between the two substrates and in contact with the silicone coating of the first substrate, the adhesive being a structural silicone adhesive suitable for contact with food, characterised in that the adhesive is obtained by crosslinking a silicone composition crosslinkable by a polyaddition reaction.

[0010] Another subject of the invention is a method for the manufacture of an article suitable for contact with food, said method comprising the following steps: providing a first substrate and a second substrate, the first substrate comprising a support having a silicone coating suitable for contact with food; depositing a silicone composition onto the silicone coating of the first substrate, the silicone composition being crosslinkable by a polyaddition reaction and suitable for contact with food; bonding the second substrate and the first substrate together such that the silicone composition is between the two substrates; Crosslinking the silicone composition to bond two substrates together with a structural silicone adhesive.

[0011] Finally, another subject of the present invention is the use of a structural silicone adhesive which is suitable for food contact and which is obtainable by crosslinking a silicone composition crosslinkable by a polyaddition reaction, for the manufacture of articles suitable for contact with food. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 shows a coating tool with two cylinders and a heated doctor blade. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Detailed Description of the Invention Unless otherwise indicated, all viscosities of silicone oils referred to in this disclosure correspond to "Newtonian" dynamic viscosities at 25°C, i.e. dynamic viscosities measured in a manner known per se using a Brookfield viscometer with a shear rate gradient sufficiently low that the measured viscosity is independent of the shear rate gradient.

[0014] A subject of the present invention is therefore an article suitable for contact with food comprising a first substrate and a second substrate joined by an adhesive, said adhesive being a structural silicone adhesive.

[0015] For purposes of this specification, an adhesive may be said to be "structural" if it does not become a weak point in the assembly.

[0016] It is important to note that the structural silicone adhesive defined in the present invention is not a PSA (pressure sensitive adhesive). A PSA forms a bond with a substrate by simply contacting or applying light pressure to bond the adhesive to the substrate surface. A PSA adhesive is soft enough to wet the substrate surface, but hard enough not to flow when pressure is applied to the bonded area, resulting in a physical bond. When the adhesive and the substrate surface are in close proximity, van der Waals type intermolecular interactions may contribute significantly to the adhesive strength. Therefore, a PSA forms a physical bond with the substrate surface, rather than a chemical bond. A chemical bond can be defined as a bond between reactive chemical groups at the interface between the adhesive and the substrate. In contrast, a physical bond can be defined as a temporary or reversible non-chemical bond that occurs due to physical interaction between the adhesive and the substrate. Silicone PSA compositions are generally in the form of a solution in an organic solvent, typically toluene and / or xylene, consisting of a hydroxylated silicone resin of the MQ(OH) type and a linear silicone rubber.

[0017] In contrast, without wishing to be limited by this theory, the structural silicone adhesive of the present invention, which is not a PSA, can form a chemical bond with the substrate, thereby ensuring good adhesion between the two substrates. Preferably, the failure between two substrates assembled using the structural silicone adhesive of the present invention is a cohesive failure. In this specification, the expression "cohesive failure" refers to failure that occurs within the body of the material, as opposed to "adhesive failure" that occurs at the interface between the adhesive and the substrate.

[0018] The silicone adhesive according to the invention must be suitable for contact with food, which in the field of food packaging means that the material of which it is made meets regulatory requirements or standards that ensure that it does not pose a toxic risk to food or drink.

[0019] In Europe, reference can be made to Regulation (EC) 1935 / 2004, which provides general guidelines for all materials intended to come into contact with food, and in particular the recommendations of the German BfR and Title 21 of the CFR, prepared by the US FDA.

[0020] Under normal conditions of use, the raw materials used must not release into foods quantities of components which may present a risk to human health or which may cause an unacceptable change in the structure of such foods, whether or not this adversely affects the organic quality of those foods.

[0021] The silicone adhesive according to the present invention, which is not a PSA, is obtained by crosslinking a crosslinkable silicone composition by polyaddition reaction. Preferably, the silicone composition crosslinkable by polyaddition reaction comprises: Silicon-bonded C 2 ~C 12 at least one polyorganosiloxane A having at least two alkenyl groups per molecule; at least one polyorganosiloxane 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.

[0022] Silicon-bonded C 2 ~C 12 The polyorganosiloxane A having at least two alkenyl groups per molecule may preferably be a linear polyorganosiloxane composed of: at least two siloxyl units of the formula: YaR 1 b SiO (4-a-b) / 2 (Wherein, Y is C 2 ~C 12 R represents an alkenyl group, preferably a vinyl group; 1 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms, and is preferably selected from an alkyl group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, or a propyl group, 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 Optionally, the unit R 1 c SiO (4-c) / 2 (In the formula, R 1 has the same meaning as above, where c=2 or 3.

[0023] In the above formula, multiple R 1 It is understood that when groups are present they may be the same or different from one another.

[0024] Preferably, the polyorganosiloxane 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 silicone composition according to the present invention does not contain a linear silicone rubber.

[0025] Silicon-bonded C 2 ~C 12 The polyorganosiloxane A having at least two alkenyl groups per molecule preferably contains siloxyl units R 1 2 SiO 2 / 2 , Y.R. 1 SiO 2 / 2 and Y 2 SiO 2 / 2 and a siloxyl unit "D" selected from the group consisting of siloxyl units YR 1 2 SiO 1 / 2 , Y 2 R 1 SiO 1 / 2 and R 1 3 SiO 1 / 2 and terminal siloxyl units "M" selected from the group consisting of: 1 is as stated above.

[0026] Examples of terminal units "M" include trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy, or dimethylhexenylsiloxy groups.

[0027] Examples of units "D" include dimethylsiloxy, methylphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyldecenylsiloxy, or methyldecadienylsiloxy.

[0028] Examples of linear polyorganosiloxanes which can be polyorganosiloxane A according to the invention are: · Dimethylvinylsilyl terminated poly(dimethylsiloxane); · Dimethylvinylsilyl terminated poly(dimethylsiloxane-co-methylphenylsiloxane); Dimethylvinylsilyl-terminated poly(dimethylsiloxane-co-methylvinylsiloxane); and · Trimethylsilyl terminated poly(dimethylsiloxane-co-methylvinylsiloxane).

[0029] Preferably, polyorganosiloxane A comprises terminal dimethylvinylsilyl units, more preferably polyorganosiloxane A is a dimethylvinylsilyl-terminated poly(dimethylsiloxane).

[0030] Preferably, polyorganosiloxane A has a content by weight of alkenyl units of 0.001% to 30%, preferably 0.01% to 10%, more preferably 0.02% to 5%.

[0031] The silicone composition preferably contains polyorganosiloxane A in an amount of 50% by weight to 95% by weight, and more preferably contains polyorganosiloxane A in an amount of 60% by weight to 90% by weight.

[0032] According to one embodiment, the silicone composition according to the present invention comprises 2 ~C 12 It is possible to include branched polyorganosiloxanes or resins that contain alkenyl units. Branched polyorganosiloxanes, also called resins, contain siloxyl units "T" (R 1 SiO 3 / 2 ) and / or siloxyl units "Q" (SiO 4 / 2 ) symbol R 1 are as described above. Examples of branched polyorganosiloxanes are as follows: · trimethylsilyl- and dimethylvinylsilyl-terminated poly(dimethylsiloxanes) (methylsiloxanes) consisting of trimethylsiloxy units "M", dimethylvinylsiloxy units "M", dimethylsiloxy units "D" and methylsiloxy units "T"; and Resins consisting of trimethylsiloxy units "M", dimethylvinylsiloxy units "M" and "Q"; and A resin consisting of trimethylsiloxy units "M", methylvinylsiloxy units "D" and "Q".

[0033] Nevertheless, according to a preferred embodiment, the silicone composition is a branched polyorganosiloxane or 2 ~C 12 Contains no resin containing alkenyl units.

[0034] Polyorganosiloxane B is a polyorganosiloxane having at least two SiH units per molecule. It is therefore a polyorganohydrogensiloxane. Preferably, compound B contains at least three SiH units.

[0035] According to a preferred embodiment, the silicone composition of the invention comprises one or more polyorganosiloxanes B in a mixture.

[0036] According to a preferred embodiment, the silicone composition according to the present invention comprises at least one polyorganosiloxane having 2 SiH units per molecule and at least one polyorganosiloxane having 3 or more SiH units per molecule.

[0037] According to one embodiment of the present invention, the silicone composition comprises at least one linear polyorganosiloxane B having at least two SiH units per molecule and a polyorganosiloxane B having a branched structure, such as a silicone resin.

[0038] The polyorganosiloxane B may advantageously be a polyorganosiloxane containing at least two, preferably at least three, siloxyl units of the formula: d R 2 e SiO (4-d-e) / 2 (In the formula, 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; and, optionally, other units of the formula: R 2 f SiO (4-f) / 2 (In the formula, R 2has the same meaning as above, and f=0, 1, 2 or 3.

[0039] In the above formula, there are multiple R 2 When groups are present, they may be the same or different.

[0040] Preferably, R 2 R may represent a monovalent group selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, and an aryl group having 6 to 12 carbon atoms, which may be substituted with at least one halogen atom such as chlorine or fluorine. 2 may advantageously be selected from the group consisting of methyl, ethyl, propyl, 3,3,3-trifluoropropyl, xylyl, tolyl and phenyl. The symbol d is preferentially equal to 1.

[0041] Polyorganosiloxane B may have a linear, branched or cyclic structure. The degree of polymerization is preferably 2 or more. In general, the degree of polymerization is less than 5000. The viscosity of polyorganosiloxane B is preferably 1 mPa·s to 5000 mPa·s, more preferably 1 mPa·s to 2000 mPa·s, and further preferably 5 mPa·s to 1000 mPa·s.

[0042] In the case of linear polymers, they are represented by the units R 2 2 SiO 2 / 2 and R 2 HSiO 2 / 2 and a siloxyl unit "D" selected from the group consisting of units R 2 3 SiO 1 / 2 and R 2 2 HSiO 1 / 2 wherein R consists essentially of terminal siloxyl units "M" selected from 2 has the same meaning as above.

[0043] Examples of linear polyorganohydrogensiloxanes which can be compound B according to the invention are: · Hydrogen dimethylsilyl terminated poly(dimethylsiloxane); · Trimethylsilyl terminated poly(dimethylsiloxane-co-methylhydrogensiloxane); · Hydrogen dimethylsilyl terminated poly(dimethylsiloxane-co-methylhydrogensiloxane); · Trimethylsilyl-terminated poly(methylhydrogensiloxane); ·Cyclic poly(methylhydrogensiloxane).

[0044] In one embodiment, polyorganosiloxane B of the silicone composition according to the invention comprises a linear polyorganohydrogensiloxane or a mixture of linear polyorganohydrogensiloxanes.

[0045] In one embodiment, polyorganosiloxane B of the silicone composition according to the present invention comprises polyorganohydrogensiloxane B which is a poly(dimethylsiloxane-co-methylhydrogensiloxane) having hydrogen dimethylsilyl ends, and polyorganohydrogensiloxane B which is a poly(methylhydrogensiloxane) having trimethylsilyl ends.

[0046] When the polyorganohydrogensiloxane B has a branched structure, it is preferably selected from the group consisting of silicone resins of the following formulae: · M'Q, where the hydrogen atom bonded to the silicon atom is held by the M group; · MM'Q, where the hydrogen atom bonded to the silicon atom is held by part of the M unit; · MD'Q, in which the hydrogen atom attached to the silicon atom is held by a D group; · MDD'Q, in which the hydrogen atom attached to the silicon atom is held by part of the D group; · MM'TQ, where the hydrogen atoms bonded to silicon atoms are held by some of the M units; · MM'DD'Q, where the hydrogen atom bonded to the silicon atom is held by some of the M and D units; and mixtures thereof, Where M = formula R 2 3 SiO 1 / 2 Siloxyl unit of formula M' = R 2 2 HSiO 1 / 2 Siloxyl unit of formula R 2 2 SiO 2 / 2 D' = siloxyl unit of formula R 2 HSiO 2 / 2 Siloxyl unit of formula T = R 2 3 SiO 1 / 2 and Q = siloxyl unit of formula SiO 4 / 2 where R 2 has the same meaning as above.

[0047] In one embodiment, the polyorganosiloxane B of the silicone composition according to the invention comprises one or more linear polyorganohydrogensiloxanes in a mixture and a silicone resin.

[0048] In one embodiment, polyorganosiloxane B of the silicone composition according to the present invention includes polyorganohydrogensiloxane B which is a poly(dimethylsiloxane-co-methylhydrogensiloxane) having hydrogen dimethylsilyl ends, polyorganohydrogensiloxane B which is a poly(methylhydrogensiloxane) having trimethylsilyl ends, and a silicone resin.

[0049] Preferably, polyorganosiloxane B has a content of hydrosilyl Si-H functional groups of 0.2% to 91%, more preferably 3% to 80%, even more preferably 15% to 70%.

[0050] Advantageously, the molar ratio of hydrosilyl Si-H functional groups of polyorganosiloxane B to the alkene functional groups of polyorganosiloxane A is between 0.01 and 20, preferably between 0.1 and 10, preferentially between 0.5 and 5, more preferentially between 1 and 5 and even more preferentially between 1 and 3.

[0051] The silicone composition according to the present invention preferably contains 0.1% to 20% by weight of polyorganosiloxane B, more preferentially 0.1% to 10% by weight, and even more preferentially 0.5% to 5% by weight.

[0052] The hydrosilylation catalyst C can be selected in particular from platinum and rhodium compounds, but also from silicon compounds, as described, for example, in WO 2015 / 004396 and WO 2015 / 004397, germanium compounds, as described, for example, in WO 2016 / 075414, or nickel, cobalt or iron complexes, as described, for example, in WO 2016 / 071651, WO 2016 / 071652 and WO 2016 / 071654. The catalyst C is preferably a compound derived from at least one metal belonging to the platinum group. These catalysts are well known. In particular, the complexes of platinum with organic products described in US Patent No. 3,159,601, US Patent No. 3,159,602, US Patent No. 3,220,972 and EP Patent Application Publication No. 0,057,459, EP Patent Application Publication No. 0,188,978 and EP Patent Application Publication No. 0,190,530, the complexes of platinum with vinyl-containing organosiloxanes described in US Patent No. 3,419,593, US Patent No. 3,715,334, US Patent No. 3,377,432 and US Patent No. 3,814,730 can be used. Alternatively, photoactivatable hydrosilylation catalysts can be used. The catalysts can be activated by irradiation, in particular by UV irradiation.

[0053] Preferably, catalyst C is a compound derived from platinum. In this case, the amount of catalyst C calculated based on 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 by mass, based on the total weight of the silicone composition. Alternatively, the amount of catalyst C calculated based on the weight of platinum metal can be 5 ppm to 200 ppm or less, more preferably 20 ppm to 200 ppm by mass.

[0054] Preferably, catalyst C is Karstedt platinum.

[0055] The silicone composition according to the present invention may optionally contain a crosslinking inhibitor D. Crosslinking inhibitors are designed to slow down the crosslinking reaction and are also called retarders. Crosslinking inhibitors are well known in the prior art. For example, cyclic polymethylvinylsiloxanes and acetylenic alcohols as described in U.S. Pat. No. 3,923,705, acetylenic alcohols as described in U.S. Pat. No. 3,445,420, heterocyclic amines as described in U.S. Pat. No. 3,188,299, diallyl maleate and other dialkyl esters as described in U.S. Pat. No. 4,256,870, olefinic siloxanes as described in U.S. Pat. No. 3,989,667, and dialkyl ethylene dicarboxylates as described in U.S. Pat. No. 4,347,346. Hydrazines, triazoles, phosphines, mercaptans, organic nitrogen compounds, acetylenic alcohols, silylated acetylenic alcohols, maleates, fumarates, ethylenically unsaturated or aromatic amides, ethylenically unsaturated isocyanates, olefinic siloxanes, unsaturated hydrocarbon monoesters and diesters, conjugated ene-ynes, hydroperoxides, nitriles and diaziridines are also included. The crosslinking inhibitor D is preferably 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 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-hexyne-3 -ol, 1-ethynylcyclopentanol, 1-phenyl-2-propynol, 3-methyl-1-penten-4-yn-3-ol, 3-methyl-1-dodecin-3-ol, 3,7,11-trimethyl-1-dodecin-3-ol, diphenyl-1,1-propyn-2-ol-1, 3,6-diethyl-1-nonyn-3-ol, 3-methyl-1-pentadecin-3-ol and mixtures thereof. Acetylenic alcohols are highly preferred as crosslinking inhibitors D according to the invention, in particular 1-ethynyl-1-cyclohexanol (ECH) being most preferred.According to one embodiment, the silicone composition D comprises from 1 ppm to 1000 ppm, preferably from 20 ppm to 500 ppm, of the crosslinking inhibitor D relative to the total weight of the silicone composition.

[0056] The silicone composition crosslinkable by polyaddition reaction may optionally contain a filler. According to one embodiment, the silicone composition contains between 5% and 40% by weight of filler relative to the total weight of the silicone composition. Advantageously, the silicone composition contains between 10% and 30% by weight of filler.

[0057] The optional fillers are preferably mineral. They may be very finely divided products with an average particle size of less than 0.1 μm. The fillers are in particular siliceous. Siliceous materials can function as reinforcing or semi-reinforcing fillers. Reinforcing siliceous fillers are selected from colloidal silica, combustion precipitated silica powders, and mixtures thereof. These powders generally have an average particle size of less than 0.1 μm (micrometer) and a particle size of less than 30 μm. 2 / g, preferably 30 to 350m 2 / g. Semi-reinforcing siliceous fillers such as diatomaceous earth and crushed quartz can also be used. These silicas can be incorporated as is or after treatment with organosilicon compounds traditionally used for this purpose. These compounds include methylpolysiloxanes such as hexamethyldisiloxane, octamethylcyclotetrasiloxane, methylpolysilazanes such as hexamethyldisilazane, hexamethylcyclotrisilazane, tetramethyldivinyldisilazane, chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, methylvinyldichlorosilane, alkoxysilanes such as dimethyldimethoxysilane, dimethylvinylethoxysilane, trimethylmethoxysilane, and mixtures thereof. Non-siliceous mineral materials can be used as semi-reinforcing mineral fillers or extending fillers. Examples of non-siliceous fillers which can be used alone or in mixtures include calcium carbonate, which may be surface treated with organic acids or organic acid esters, calcined clays, titanium dioxide in the rutile form, oxides of iron, zinc, chromium, zirconium or magnesium, various forms of alumina (hydrated or non-hydrated), boron nitride, lithopone, barium metaborate, barium sulfate, glass microbeads, etc. These fillers are coarser, with an average particle size generally exceeding 0.1 μm and a specific surface area generally greater than 30 m. 2 / g. These fillers may be surface modified by treatment with various organosilicon compounds conventionally used for this purpose.

[0058] Preferably, the filler is silica, more preferably fumed silica. Advantageously, the silica is 75 ml 2 / g~410m 2 / g BET specific surface area.

[0059] The silicone composition according to the present invention may also contain other functional additives commonly used in silicone compositions. Commonly used functional additives include adhesion promoters, adhesion modifiers, thickening additives, heat resistance additives, oil resistance or fire resistance additives, such as metal oxides, virucides, fungicides, anti-wear additives, and pigments (organic or mineral).

[0060] However, some additives commonly used in silicone compositions are not compatible with food contact applications, and therefore the silicone composition preferably does not contain additional additives.

[0061] Typically, the adhesion promoting compound may be an organosilicon compound that contains an adhesion promoting functional group. In particular, it may be an organosilicon compound that includes: one or more hydrolyzable groups bonded to silicon atoms, typically alkoxy groups bonded to silicon atoms, and One or more organic groups selected from a mercaptan group, a urea group, an isocyanurate group, a (meth)acrylate group, an epoxy group, and an alkenyl group.

[0062] Mention may be made, for example, of the following compounds, either alone or in mixture: vinyltrimethoxysilane (VTMO), 3-glycidyloxypropyltrimethoxysilane (GLYMO), methacryloxypropyltrimethoxysilane (MEMO), [H 2 N(CH 2 ) 3 ]Si(OCH 2 CH 2 CH 3 ) 3 , [H 2 N(CH 2 ) 3 ]Si(OCH 3 ) 3 , [H 2 N(CH 2 ) 3 ]Si(OC 2 H 5 ) 3 , [H 2 N(CH 2 ) 4 ]Si(OCH 3 ) 3 , [H 2 NCH 2 CH(CH 3 )CH 2 CH 2 ]SiCH 3 (OCH 3 ) 2, [H 2 NCH 2 ]Si(OCH 3 ) 3 , [nC 4 H 9 -HN-CH 2 ]Si(OCH 3 ) 3 , [H 2 N(CH 2 ) 2 NH(CH 2 ) 3 ]Si(OCH 3 ) 3 , H 2 N(CH 2 ) 2 NH(CH 2 ) 3 ]Si(OCH 2 CH 2 OCH 3 ) 3 , [CH 3 NH(CH 2 ) 2 NH(CH 2 ) 3 ]Si(OCH 3 ) 3 , [H(NHCH 2 CH 2 ) 2 NH(CH 2 ) 3 ]Si(OCH 3 ) 3 , HS(CH 2 ) 3 Si(OCH 3 ) 3 , N.H. 2 CONH 2 (CH 2 ) 3 Si(OCH 3 ), or polyorganosiloxane oligomers, for example containing 2 to 100 silicon atoms and containing more than 20% of such organic groups. Also included are organosilicon compounds containing at least one, preferably at least two alkoxy groups and at least one epoxy group bonded to a silicon atom.

[0063] Additionally, the adhesion promoting compound may be an organotitanium compound, preferably a titanium chelate or a compound of the formula Ti(OR) 4 wherein R is a linear or branched C 1 ~C 8 It is selected from an alkyl group, an alkoxyalkyl group, or an acyl group. More preferably, the organotitanium compound is selected from titanium alkoxides such as titanium butoxide, titanium isopropoxide, titanium methoxide, and octyl titanate. More preferably, the organotitanium compound is titanium butoxide (TBOT).

[0064] According to a preferred embodiment, the silicone composition according to the invention does not comprise any adhesion promoting compound. In particular, the silicone composition according to the invention preferably does not comprise any of the adhesion promoting compounds mentioned individually above.

[0065] Additionally, the silicone composition according to the present invention is preferably free of organic solvents, typically free of toluene or xylene.

[0066] According to a preferred embodiment, the silicone composition crosslinkable by polyaddition reaction according to the invention comprises, based on the total weight of the silicone composition: 50% to 95%, preferably 60% to 90%, of silicon-bonded C 2 ~C 12 A polyorganosiloxane A having at least two alkenyl groups per molecule; 0.1% to 20%, preferably 0.5% to 5%, of polyorganosiloxane B having at least 2 SiH units per molecule, 1 ppm to 400 ppm, preferably 2 ppm to 200 ppm, of a hydrosilylation catalyst C (calculated by weight of metal), optionally from 1 ppm to 1000 ppm, preferably from 20 ppm to 500 ppm, of a crosslinking inhibitor D, Optionally, 5% to 40%, preferably 10% to 30%, of silica filler.

[0067] According to a particular embodiment, the silicone composition crosslinkable by polyaddition reaction according to the invention comprises, based on the total weight of the silicone composition: 50% to 95%, preferably 60% to 90%, of silicon-bonded C 2 ~C 12 A polyorganosiloxane A having at least two alkenyl groups per molecule; 0.1% to 20%, preferably 0.5 to 5%, of polyorganosiloxane B having at least two SiH units per molecule and polyorganosiloxane B having a branched structure such as a silicone resin, 1 to 400 ppm, preferably 2 to 200 ppm, of a hydrosilylation catalyst C (calculated by weight of metal), optionally from 1 ppm to 1000 ppm, preferably from 20 ppm to 500 ppm, of a crosslinking inhibitor D, · Optionally 5% to 40%, preferably 10% to 30%, of silica filler.

[0068] The silicone composition crosslinkable by a polyaddition reaction according to the present invention preferably has a viscosity of more than 5000 mPa·s, and more preferably has a viscosity of 10000 mPa·s to 100000 mPa·s.

[0069] According to one embodiment, the silicone composition according to the invention can be produced from a two-component system in the form of two separate parts intended to be mixed to form said silicone composition, characterized in that one of the two parts contains catalyst C and does not contain polyorganosiloxane B, and the other part contains polyorganosiloxane B and does not contain catalyst C.

[0070] The silicone composition can be prepared by mixing all the various components as described above. Mixing can be carried out under an inert gas atmosphere using a mixer suitable for such compositions, such as a kneading mixer or a planetary mixer. Alternatively, the two parts of the composition can be stored in a two-part adhesive cartridge and mixing is carried out by a static mixer at the outlet of the cartridge.

[0071] After crosslinking, the silicone composition of the present invention forms a structural silicone adhesive that allows for the assembly of multiple substrates.

[0072] The article suitable for contact with food according to the present invention comprises a first substrate and a second substrate, the two substrates being joined by an adhesive as described above. The first substrate comprises a support coated with a silicone coating suitable for contact with food.

[0073] The support is preferably a fibrous support. Examples of fibrous supports include various types of paper (such as kraft paper of any degree of beating, glassine, greaseproof paper, etc.), cardboard, vegetable parchment, polyethylene- or carboxymethylcellulose-coated paper, cellulose sheets, etc. Highly preferably, the support is selected from paper and cardboard. In the case of a paper support, a paper can be selected that preferably has a Bendtsen porosity of 0.1 ml / min to 500 ml / min according to the ISO5636-3 standard and a medium COBB value of 5 to 30 according to the ISO535 method.

[0074] Alternatively, the support may consist of a sheet of polymeric material such as polyethylene, polypropylene, polyethylene terephthalate, or natural polymers.

[0075] Again, the support may be metallic, for example a metal sheet.

[0076] According to one embodiment, the support according to the present invention is a flexible support. In this specification, the term "flexible support" refers to a support that can be bent or folded by human force alone without breaking or being damaged. In contrast, according to another embodiment, the support according to the present invention is a rigid support or a semi-rigid support. In this specification, the term "rigid support or semi-rigid support" refers to a support that cannot be easily bent or folded by human force alone without breaking or being damaged.

[0077] Preferably the support is in sheet or film form, although other forms are possible with the present invention.

[0078] According to the present invention, the support of the first substrate is coated with a silicone coating suitable for contact with food. The silicone coating may be present on one side of the support or on both sides. Such coatings are well known to those skilled in the art. Typically, the silicone coating suitable for contact with food is obtained by crosslinking the silicone composition after coating on the support. The silicone composition may be a silicone emulsion or a solventless silicone composition. For silicone emulsions, reference may be made in particular to EP 0253747 and WO 99 / 35181 and WO 2018 / 178321. For solventless silicone compositions, reference may be made, for example, to WO 2005 / 059039.

[0079] Preferably, suitable silicone coatings are composed of water-repellent, non-sticky coatings or films obtained by applying to a substrate and then crosslinking silicone emulsions. Said silicone emulsions can be crosslinked by polycondensation or polyaddition chemistry. Preferably, said silicone emulsions are aqueous silicone emulsions that can be crosslinked by polyaddition reaction to silicone elastomers. Polyaddition chemistry is generally preferred because it is suitable for food contact, since some tin-based polycondensation catalysts cannot be used. Furthermore, without wishing to be limited by this theory, silicone coatings obtained by polyaddition reaction may have residual chemical functional groups on the surface that may be used as anchoring points for structural silicone adhesives that utilize the same crosslinking chemistry.

[0080] This may in particular be an aqueous silicone emulsion that can be crosslinked by a polyaddition reaction to give a silicone elastomer, including: Silicon-bonded C 2 ~C6 at least one polyorganosiloxane having at least two alkenyl-type unsaturated functional groups per molecule, at least one polyorganosiloxane having at least three silicon-bonded hydrogen atoms per molecule; at least one polyaddition catalyst, at least one emulsifier, ·water, optionally at least one crosslinking inhibitor, optionally at least one pH adjusting agent, selected to maintain the pH of the emulsion between 5 and 9, preferably between 5.5 and 8.5, more preferably between 6 and 8; optionally at least one formulation additive, such as a bactericide, e.g. sorbic acid, an antifreeze and / or a wetting agent, e.g. 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 (siliceous fillers are particularly preferred), a dye or pigment, an acidifying agent, e.g. acetic acid.

[0081] However, some additives commonly used in silicone compositions are not compatible with food contact applications, and therefore the silicone composition preferably does not contain additional additives.

[0082] Substrates, particularly silicone papers, coated with a silicone coating according to the present invention are typically produced by in-line coating, i.e., coating directly on the machine that produces the substrate after the sheet has been formed.

[0083] The silicone coating is preferably 0.05 g / m 2 ~1g / m 2 However, the amount of silicone emulsion applied to the support must be adjusted taking into consideration the penetration of silicone into the support. For example, if the penetration rate of silicone into paper is 0% to 50% and the paper is coated on both sides, the thickness of the silicone emulsion applied to the support must be adjusted to 1 m 2 The total amount of silicone per unit area is preferably 0.1 g / m 2~4g / m 2 It is.

[0084] According to the first embodiment, the second substrate of the present invention is the same as the first substrate. For example, the first substrate and the second substrate may be a folded silicone sheet. Thus, the second substrate comprises a support coated with a silicone coating suitable for contact with food. The support and the silicone coating may be as described above for the first substrate. In this configuration, the structural silicone adhesive is preferably inserted between the two substrates and contacts the silicone coating of the two substrates.

[0085] According to a second embodiment, the second substrate according to the present invention is different from the first substrate. The second substrate may be a support as described above, without a silicone coating. For example, the second substrate may be a transparent sheet made of a polymeric material. In this configuration, the structural silicone adhesive is preferably inserted between the two substrates and is in contact with the silicone coating of the first substrate, and the second substrate does not necessarily have a silicone coating.

[0086] The article suitable for contact with food according to the invention can be obtained by a process comprising the following steps: providing a first substrate and a second substrate, the first substrate comprising a support having a silicone coating suitable for contact with food; depositing a silicone composition on the silicone coating of the first substrate, the silicone composition being crosslinkable by a polyaddition reaction and suitable for contact with food; bonding the second substrate and the first substrate such that the silicone composition is between the two substrates; Crosslinking the silicone composition to bond two substrates together with a structural silicone adhesive.

[0087] The silicone composition, crosslinkable by polyaddition reaction and suitable for contact with food, can be applied onto the first substrate according to methods known to those skilled in the art. The application is carried out by pouring, dipping or extrusion using a brush or doctor blade. According to one embodiment, the silicone composition is applied continuously onto a portion of the silicone coating of the first substrate. Thus, the silicone coating of the first substrate is covered, for example, with a band of silicone composition. This embodiment is advantageous when it is desired to obtain a continuous and leak-free adhesive bond between the first substrate and the second substrate.

[0088] However, if a leak-tight adhesive bond is not desired, it is also possible in the present invention to apply the silicone composition discontinuously, only over certain areas, or in dots, for example.

[0089] The amount of the silicone composition deposited on the silicone coating of the first substrate was 1 g / m 2 ~50g / m 2 , preferably 5 g / m 2 ~20g / m 2 It may be.

[0090] Prior to the deposition of the silicone composition crosslinkable by a polyaddition reaction, the method may comprise an optional step of surface treatment of the silicone coating of said first substrate, for example corona treatment.

[0091] The second substrate and the first substrate can be joined in succession using a cylinder and contacting a doctor blade.

[0092] Silicone compositions can crosslink without external intervention if there is sufficient reactivity between the previously contacted parts. Nevertheless, it is preferred to thermally activate the crosslinking reaction. Means for thermally activating the crosslinking include conventional ovens (e.g. tunnel ovens), heated laminating rollers, infrared sources, etc. This thermal activation can be supplemented by photoactivation and / or electron beam irradiation. The crosslinking temperature may be higher than 120°C without exceeding the destruction temperature of the support, preferably between 160°C and 200°C. The duration of this thermal activation step of crosslinking may be between 0.1 and 30 seconds, preferably between 0.1 and 5 seconds.

[0093] Alternatively, the crosslinking reaction can be activated by irradiation, for example UV. For this purpose, the skilled person can select a photoactivatable polyaddition catalyst and, optionally, suitable photosensitizing additives.

[0094] Advantageously, the process for producing articles suitable for contact with food as described above can be carried out continuously by equipment known to those skilled in the art, in particular by packaging production machines.

[0095] The final thickness of the structural silicone adhesive after crosslinking is from 1 μm to 50 μm, and preferably from 5 μm to 20 μm.

[0096] The article suitable for contact with food according to the invention is advantageously a food packaging, which may be chosen, for example, from: Flexible packaging: bags and pouches, especially for leak-proof packaging, optionally with aeration valves, sandwich bags, bags with or without transparent windows, bloomer bags, etc. Semi-rigid packaging: boxes, lunch boxes, pastry boxes, burger boxes, cases, cones, punnets, pots with or without lids, cups, shells, refill cartons, cartons, etc. -Rigid packaging: cardboard box (pizza box type).

[0097] The article of the present invention has properties that are particularly beneficial to food packaging professionals and end consumers: Suitable for contact with food and meets relevant regulatory requirements. Silicones are known to be non-toxic and inert to food when properly formulated and used. In addition, due to the use of polyaddition silicone adhesives, the product does not contain tin-based catalysts. · The silicone coating and silicone adhesive allow the article to withstand a large temperature range, typically -30°C to +250°C or -70°C to +250°C. The article can be used for freezing and cooking alike. It is particularly suitable for microwave cooking. The article is water-tight. It is also non-stick and water-repellent, so food does not stick to the packaging even after storage. By selecting a structural silicone adhesive, substrates can be tightly and permanently assembled. In this way, leak-free assemblies can be produced that can be used for long-term food storage. Finally, from the viewpoint of workability, the article suitable for contact with food according to the invention can be produced at high throughput, preferably using standard industrial equipment from the packaging sector. The crosslinking speed of the adhesive is compatible with high throughput at industrial level. The viscosity of the adhesive is also compatible with industrial deposition equipment. Finally, the adhesive crosslinks without emitting any odor.

[0098] Another subject of the present invention is the use of a structural silicone adhesive suitable for contact with food, obtainable by crosslinking a crosslinkable silicone composition by a polyaddition reaction, for the manufacture of articles suitable for contact with food.

[0099] Other details or advantages of the invention will become apparent in the light of the examples given below, which are given by way of example only. EXAMPLES

[0100] Manual Coating Test The silicone composition was hand coated onto an A5 sized silicone baking parchment. A second identical baking parchment was then manually applied to the resulting coating and the assembly was allowed to crosslink as detailed below.

[0101] The silicone compositions tested were as follows:

[0102] PSA1: A toluene solution of silicone PSA consisting of polydimethylsiloxane rubber and MQ(OH) hydroxylated resin. Dry solids: 60% Viscosity: 80000mPa·s PSA2: A toluene solution of silicone PSA consisting of polydimethylsiloxane rubber and MQ(OH) hydroxylated resin. Dry solids: 60%. Viscosity: 70000 mPa·s.

[0103] Adhesive 1: A two-part RTV2 silicone composition that crosslinks by polyaddition. Part A: Per 100 copies: 74.38 parts of Si(CH 3 ) 2 CH=CH 2 a polydimethylsiloxane oil having terminal groups and a viscosity of 1500 mPa·s; 2.11 parts of Si(CH 3 ) 2 Polydimethylsiloxane oil with H-terminus and Si(CH 3 ) 3 Polyorganosiloxane oil B consisting of a terminal polymethylhydrogensiloxane oil; 23.48 parts treated fumed silica, 1 · 0.03 parts ethynyl-1-cyclohexanol (ECH).

[0104] Part B: Per 100 copies: 99 parts of Si(CH 3 ) 2 CH=CH 2 Polydimethylsiloxane oil with terminal and viscosity of 100000 mPa·s, 1 part Karstedt platinum catalyst (10 ppm based on the total weight of the composition). Mix parts A and B such that the ratio of parts A to B is equal to 10. Adhesive viscosity 1:40000mPa·s.

[0105] Adhesive 2 (Modification 3): A two-part silicone composition of the RTV2 type, crosslinked by polyaddition. Part A: Per 100 copies: 75.04 parts of Si(CH 3 ) 2 CH=CH 2 a polydimethylsiloxane oil having terminal groups and a viscosity of 1500 mPa·s; 1.25 parts of polyorganosiloxane B, a resin of the MM'Q type in which the hydrogen atoms bonded to silicon atoms are held by M groups, and Si(CH 3 ) 3 Polymethylhydrogensiloxane oil with terminal group and Si(CH 3 ) 2 and a poly(dimethylsiloxane-co-methylhydrogensiloxane) oil having an H-terminus. 23.68 parts treated fumed silica, 0.03 parts of 1-ethynyl-1-cyclohexanol (ECH).

[0106] Part B: 99 parts of Si(CH 3 ) 2 CH=CH 2 Polydimethylsiloxane oil with terminal and viscosity of 100000 mPa·s, 1 part Karstedt platinum catalyst (10 ppm based on the total weight of the composition). Mix parts A and B such that the ratio of parts A to B is equal to 10. Adhesive viscosity 2: 40000mPa·s.

[0107] Adhesive 3 (Modification 7): A two-part silicone composition of the RTV2 type, crosslinked by polyaddition. Part A: Per 100 copies: 75.06 parts of Si(CH3 ) 2 CH=CH 2 a polydimethylsiloxane oil having terminal groups and a viscosity of 1500 mPa·s; 1.22 parts of polyorganosiloxane oil B, having a content of Si(CH 3 ) 3 Polymethylhydrogensiloxane oil with terminal group and Si(CH 3 ) 2 and a poly(dimethylsiloxane-co-methylhydrogensiloxane) oil having an H-terminus. 23.69 parts treated fumed silica, 0.03 parts of 1-ethynyl-1-cyclohexanol (ECH).

[0108] Part B: Per 100 copies: 99 parts of Si(CH 3 ) 2 CH=CH 2 Polydimethylsiloxane oil with terminal and viscosity of 100000 mPa·s, 1 part Karstedt platinum catalyst (10 ppm based on the total weight of the composition).

[0109] Mix parts A and B such that the ratio of part A to part B is equal to 10. Adhesive viscosity 3:40000mPa·s.

[0110] Adhesive 4 (comparison): A two-part silicone composition of the RTV2 type, which crosslinks by polyaddition. Part A: Si(CH 3 ) 2 CH=CH 2 Polydimethylsiloxane oil with terminal groups, Si(CH 3 ) 2 Polydimethylsiloxane oil with H-terminus, Si(CH 3 ) 3Terminated poly(methylhydrogensiloxane-co-dimethylsiloxane) oil, treated fumed silica, 1-ethynyl-1-cyclohexanol (ECH), 3-glycidyloxypropyltrimethoxysilane (GLYMO). Part B: Si(CH 3 ) 2 CH=CH 2 Terminated polydimethylsiloxane oil, treated fumed silica, Karstedt platinum catalyst (10 ppm based on the total weight of the composition), titanium butoxide (TBOT). Mix parts A and B so that the ratio of part A to part B is equal to 10. Viscosity of adhesive 4:40000 mPa·s. This composition is not suitable for contact with food due to the presence of adhesion promoters such as 3-glycidyloxypropyltrimethoxysilane (GLYMO) and titanium butoxide (TBOT).

[0111] Adhesive 5 (comparison): A 1 part RTV1 type silicone composition which crosslinks by polycondensation. Formulation: Hydroxy-terminated polydimethylsiloxane oil, treated fumed silica, methyltriacetoxysilane, tetra-n-butyl titanate (polycondensation catalyst).

[0112] The adhesive quality was evaluated with a dynamometer using the T-peel test method according to ASTM D1876. Particular attention was paid to the rupture characteristics of the specimens, which must be absolutely tightly adhered (the paper breaks during the test) to ensure optimal performance of the assembly.

[0113] The results are reported in Table 1 below:

[0114] [Table 1]

[0115] The results obtained with PSA-type compositions are inconclusive and significantly inferior to structural adhesives.The adhesives of inventions 1, 2 and 3 are silicone compositions that crosslink by polyaddition, and therefore are suitable for contact with food, have no significant drawbacks in terms of forming ability (e.g. odor) and provide satisfactory adhesion.

[0116] 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 a satisfactory adhesive result. Furthermore, comparative example 5 has the disadvantage of releasing acetic acid, since it is an adhesive that crosslinks by polycondensation.

[0117] Moreover, inventive adhesives 2 and 3 provide satisfactory results despite the low thickness of the applied adhesive, which makes these embodiments particularly advantageous on an industrial scale.

[0118] Cylinder Coating Test A coating tool with two cylinders and a heated doctor blade was used. The tool is shown in Figure 1: A first substrate (1) and a second substrate (2) were attached to the cylinders. The adhesive composition was applied using an attachment means (3). A heated metal doctor blade (4) and a second support were brought into contact before passing between two heated metal laminating cylinders (5). The gap (6) between the two cylinders was set at 0.1 mm. The passage through the tool was done manually and was estimated at about 10 m / min. The target temperatures of the doctor blade and the two metal cylinders were electronically controlled.

[0119] Substrate: Commercially available silicone-coated baking parchment Silicone adhesive composition: Same as Adhesive 1 above.

[0120] Crosslinking is visually assessed by a scissor blade fouling test: Immediately after crosslinking, a cutting test is performed using a paper cutter and scissors to assess blade fouling. The blade of the cutting tool should not be dirty or have any silicone on it.

[0121] The adhesion is evaluated manually: immediately after crosslinking, the two parts of the assembly are held tightly during a shear test. The assembly must be able to withstand the stresses exerted by the manufacturing tool.

[0122] The results are shown in Table 2 below: [Table 2]

[0123] 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, the mechanical performance of the assemblies was observed to be maintained.

Claims

1. 1. An article suitable for contact with food, comprising a first substrate and a second substrate joined by an adhesive, the first substrate comprising a support coated with a silicone coating suitable for contact with food, the adhesive being interposed between the two substrates and in contact with the silicone coating of the first substrate, the adhesive being a structural silicone adhesive suitable for contact with food, the adhesive being obtained by crosslinking a silicone composition crosslinkable by a polyaddition reaction.

2. The silicone composition capable of crosslinking by a polyaddition reaction is ・C bonded to silicon 2 ~C 12 At least one polyorganosiloxane A having at least two alkenyl groups per molecule; at least one polyorganosiloxane 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 The article of claim 1 comprising:

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

4. The article according to any one of claims 1 to 3, characterized in that the silicone composition is free of organic solvents, typically toluene or xylene.

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

6. An article 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 cardboard.

7. 7. An article according to any one of claims 1 to 6, characterized in that the silicone coating suitable for contact with food consists of a water-repellent, non-sticky coating or film obtained by applying to the substrate and then crosslinking a silicone emulsion, preferably an aqueous silicone emulsion which can be crosslinked by a polyaddition reaction to give a silicone elastomer.

8. An article according to any one of claims 1 to 7, characterized in that the article is a food packaging, preferably selected from: Flexible packaging: bags and pouches, especially for leak-proof packaging, optionally with aeration valves, sandwich bags, bags with or without transparent windows, bloomer bags, etc. Semi-rigid packaging: boxes, lunch boxes, pastry boxes, burger boxes, cases, cones, punnets, pots with or without lids, cups, shells, refill cartons, cartons, etc. - Rigid packaging: cardboard box (pizza box type).

9. 1. A method for manufacturing an article suitable for contact with food, comprising the steps of: Providing a first substrate and a second substrate, the first substrate comprising a support having a silicone coating suitable for contact with food; depositing a silicone composition onto the silicone coating of the first substrate, the silicone composition being crosslinkable by a polyaddition reaction and suitable for contact with food; - joining the second substrate and the first substrate such that the silicone composition is between the two substrates; - Crosslinking the silicone composition to bond two substrates together with a structural silicone adhesive.

10. 2. Use of a structural silicone adhesive suitable for food contact, obtained by crosslinking a crosslinkable silicone composition by a polyaddition reaction, for the manufacture of an article suitable for food contact.

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