EP1238033A1

EP1238033A1 - Anti-adherent silicone/adhesive complex with stabilising additive

Info

Publication number: EP1238033A1
Application number: EP00974610A
Authority: EP
Inventors: Jean-Marc Frances; Christophe Guyot; John White
Original assignee: Rhodia Chimie SAS
Current assignee: Rhodia Chimie SAS
Priority date: 1999-10-29
Filing date: 2000-10-30
Publication date: 2002-09-11
Also published as: CA2389017A1; AU1284601A; WO2001030931A1; FR2800382A1; JP2003513143A; FR2800382B1

Abstract

The invention concerns an anti-adherent silicone/adhesive complex comprising at least a silicone coating applied on a first support and an adhesive coating applied on a second support. The invention is characterised in that said adhesive coating comprises as additive for stabilising in course of time the release force of the silicone/adhesive interface an ammonium salt or an element of group IA or IIA of the periodic table with a compound selected among: fluorophosphates, fluorosulphonates, phosphoric acid esters or salts, mono-or polycarboxylates.

Description

SILICONE COMPLEX / ADHESIVE ADHESIVE WITH ADDITIVE

STABILIZATION.

The present invention relates generally to so-called self-adhesive complexes in which a crosslinked or polymerized silicone matrix is associated with an adhesive. This silicone matrix can in particular be applied to the surface of a support so as to make it non-stick with respect to the adhesive. This type of adhesive / silicone complex is more particularly used for the production of adhesive protective papers such as labels, decorative papers and adhesive tapes.

These complexes can be prepared according to a so-called “in line” process which involves the successive stages comprising in particular the deposition of a crosslinkable and / or polymerizable organopolvsiloxane composition on a support type material, its crosslinking and / or polymerization by energy supply so as to form a silicone coating, the application on said coating of adhesive usually in the form of a wet emulsion, drying said emulsion and application ^of a second support. The adhesive / silicone complex thus formed is then generally stored for a more or less prolonged period on reels.

The primary function of the silicone coating of these complexes is therefore to provide the interface between the support and the adhesive. However, it must also establish the adhesive connection to a sufficiently low that they can be easily separated from one ^another.

Accordingly, an essential property of these complexes should be to impart a peel force with respect to the adhesive sufficiently low, and can be stabilized during prolonged storage complex on the reels at ^the end of their manufacture. Indeed, since these coils can sometimes reach more than a meter in diameter, very strong pressure is then exerted on the adhesives. Under this pressure, the adhesive can interact with the silicone and cause detachment difficulties, incompatible with the end use of these complexes, in particular as easily peelable adhesive labels or adhesive tapes. In this case, this bonding force, also called detachment force, can be quantified. Although it can vary significantly depending on the measurement method used, it can be broadly characterized, for a low release speed of the order of 30 cm / min, as follows:

- a release force of less than 23.62 g / cm is considered to be low,

- a release force greater than 23.62 g / cm and less than 59.05 g / cm is considered to be medium, and

- a release force greater than 59.05 g / cm and preferably less than 157.48 g / cm is considered high. The present invention aims in particular to provide a silicone / adhesive complex whose release force can be stabilized at a value less than 59.05 g / cm, appreciated for a release speed of the order of 30 cm / min.

More particularly, the object of the invention is to provide non-stick silicone systems, the release forces of which also remain stable during the aging of the complexes and therefore during their storage, in particular in the circumstances mentioned above.

This objective is precisely achieved according to the present invention by the introduction into the adhesive component of a silicone / adhesive complex of at least one stabilizer so as to act on an interface between the adhesive and the silicone. More particularly, the present invention relates to a silicone / non-stick adhesive complex comprising at least one silicone coating applied to a first support and an adhesive coating applied to a second support, characterized in that said adhesive coating comprises as an additive intended to stabilize over time the detachment force of a silicone / adhesive interface of at least one ammonium salt or of an element of group IA or IIA of the periodic table with a compound chosen from:

- fluorophosphates such as potassium hexafluorophosphate, - fluorosulfonates such as potassium thfluoromethanesulfonate, and

- the esters or salts of phosphoric acid such as K ₃ P0 ₄ , K ₄ P ₂ O ₇ , (Me ₃ SiO) - POK with r = 1 or 2, HK ₂ PO ₄ , KH ₂ PO ₄ .

- the mono or o poly-carboxylates of formula r R (COO) _n V, with

- R representing a linear, branched or cyclic, saturated, unsaturated or aromatic C, to C ₁₂ alkyl group and optionally substituted by one or more halogen atoms and / or carboxylic function and / or the hydrocarbon chain of which may be interrupted by one or more oxygen, sulfur and / or nitrogen atoms,

- n representing an integer between 1 and 6, preferably between 1 and 4 and

- with in the case of several carboxylate functions, the possibility for these to be positioned on the same atom or atoms distinct from the alkyl group represented by R and preferably at the end (s) of the linear or branched hydrocarbon chain represented by R. For the purposes of the present invention, the term “carboxylates” is intended to cover mono- and poly-carboxylates. The polycarboxylates can be partially or fully salified polycarboxylic acids. The degree of salification is in fact adjusted so as to give the corresponding carboxylates a satisfactory solubility in the adhesive component. As examples of carboxylates, mention may be made of monocarboxylates, such as acetates and formates; diacid carboxylates such as succinic acid; glutaric acid; adipic acid; fumaric acid and maleic acid, the carboxylates of polyacids such as polyacrylic, of polyamides and polyamines such as EDTA as well as polycarboxylates such as polyesters and in particular those of fatty acids.

According to a preferred variant of the invention, the additive is chosen from:

- the carboxylates of formula R'COO ^θ , with R 'representing a linear, branched or cyclic, saturated, unsaturated or aromatic C 1 to C ₁₂ alkyl radical and optionally substituted by one or more halogen atoms,

- - EDTA salts such as EDTA K ₃ , EDTANa _4, EDTA K ₂ and EDTA (NH ₄ ) ₂

- fluorophosphates such as potassium hexafluorophosphate, - fluorosulfonates such as potassium trifluoromethanesulfonate, and

- the esters or salts of phosphoric acid such as K ₃ P0 ₄ , K ₄ P ₂ 0 ₇ ,

(Me ₃ SiO) OK with n '= 1 or 2, HK ₂ PO ₄ , KH ₂ PO

O The additives used according to the invention preferably have at least one element from group IA or IIA of the periodic table.

The elements of group IA or IIA are preferably chosen from potassium or calcium. The following carboxylates are particularly suitable for the invention: (C ₂ H ₅ ) (C ₄ H ₉ ) CHCOOK, (CH ₃ ) (CH ₂ ) ₇ CH = CH (CH ₂ ) ₇ COOK,

(CH ₃ COO) ₂ Ca, CH ₃ -COOK, CF ₃ COOK, (CH ₃ O) ₂ P (0) CH ₂ COOK), salts EDTA K ₃ , EDTANa ₄ _ EDTA K ₂ _ EDTA (NH ₄ ) ₂ , K ₂ C0 ₃ and HK ₂ P0 ₄ . Within the meaning of the present invention, the action of the additive results in a prolonged stabilization over time, of the release force at the level of a silicone coating and adhesive coating interface, at a sufficient amplitude to be compatible with a subsequent peeling of the two coatings, for example during the final use of these complexes as easily peelable adhesive labels or adhesive tapes.

According to a first variant, the two supports are made of two separate materials, arranged so that the silicone coating of the first support is in contact with the adhesive coating of the second support. This embodiment is in particular illustrated by systems known as self-adhesive labels. In this particular case, the release force of the silicone / adhesive interface is exerted during the separation of the two supports.

In a second variant, the two supports are constituted respectively by each of the two faces of the same material. This second embodiment is in particular illustrated by the systems known as adhesive tapes. The non-stick coating, that is to say based on the silicone coating and the adhesive coating will be brought into contact during the winding of the support on itself. In this case, the release force is exerted at the silicone / adhesive interface under the effect of the separation of a lower face from an upper face of the material.

Within the meaning of the invention, a detachment force is considered to be stabilized if, compared to its original amplitude, it does not change more than a factor of 8, preferably 5 and more preferably 3, after an aging test called FINAT 10, representative of an aging of 3 to 6 months at 20 ° C under pressure conditions of 70g / cm ² . Preferably, the initial release force, evaluated according to the test

FINAT 3, representative of 20 hours aging at 20 ° C under pressure conditions of 70g / cm ² and exerted at the silicone / adhesive interface, is less than 31.49 g / cm and more preferably at 23.62 g / cm. By way of illustration of the additives which are suitable for the invention for stabilizing the release force, mention may in particular be made of potassium or calcium carbonate and bicarbonate, potassium hydrogenphthalate, potassium dimethylphosphonoacetate, potassium hydrogenotartrate, hydrogenophosphates potassium, potassium acetate, potassium oxalate and potassium trifluoromethane sulfonate and EDTA salts such as EDTA K ₃ , EDTANa _4, EDTA K _2, EDTA (NH ₄ ) ₂ .

Of course, the choice of this additive is made taking into account its degree of solubility in the adhesive component selected.

The additive can be introduced into the adhesive up to 5% by weight. Its quantity can thus vary between 0.001% and 5% and preferably between 0.01% and 1% by weight.

In the context of the present invention, one can choose an adhesive of the type: - acrylic in aqueous phase, or in solvent phase, hot-melt or photocrosslinkable,

- gums of the natural or synthetic rubber type in the aqueous phase or in the solvent phase, hot-melt or photocrosslinkable, - latex or other suitable adhesives.

In general, the adhesives coated on the surface of a wide variety of materials so as to obtain labels, tapes or any other self-adhesive material are emulsions called pressure-sensitive adhesive emulsions (PSA) which are mainly derived from acrylic polymers. These emulsions have the advantage of giving the material the ability to adhere to the surface of a support, without requiring any activation other than a low pressure. Conventionally, PSAs are obtained by polymerization mainly of alkyl acrylate monomers which are generally present in an amount of 50 to about 99% and preferably in an amount of 80 to 99% by weight, mixed if necessary with polar copolymerizable monomers such as for example acrylic acid, in smaller proportions.

In fact, these PSAs have residual acidity or formulation additives capable of interacting with functional groups present on the silicone coating to which said PSA is or must be juxtaposed and therefore of disrupting the adhesive / silicone release forces. It seems that one of the actions of the additive is precisely to neutralize, at least in part, this type of unwanted interaction. The element of group IA or IIA of the additive according to the invention is in particular capable of acting with the ends of carboxylic or carboxylate chains of the adhesive and more particularly of PSA.

As previously reported, these so-called pressure-sensitive adhesive emulsions (PSAs) are obtained by polymerization mainly of alkyl acrylate monomers.

The monomers used to prepare the PSAs are selected according to their glass transition temperature, Tg, to give the polymers incorporating them the expected behavior in terms adhesion and viscoelasticity. For this purpose, the monomers preferably have a sufficiently low glass transition temperature, generally between -70 and -10 ° C and preferably less than - 30 C. More precisely, these monomers are chosen from the group consisting of esters ( meth) acrylics such as the esters of acrylic acid and methacrylic acid with hydrogenated or fluorinated CC ₁₂ alkanols, preferably CC _a , in particular methyl acrylate, ethyl acrylate, propyl, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, tert-butyl acrylate, hexyl acrylate, heptyl acrylate, acrylate octyl, iso-octyl acrylate, decyl acrylate, dodecyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate; - vinyl nitriles including more particularly those having

3 to 12 carbon atoms, such as in particular acrylonitrile and methacrylonitrile; vinyl esters of carboxylic acid such as vinyl acetate, vinyl versatate, vinyl propionate, - ethylenic unsaturated mono- and dicarboxylic acids such as acrylic acid, methacrylic acid, itaconic acid , maleic acid, fumaric acid and the mono- and di-alkyl esters of the mono- and di-carboxylic acids of the type cited with the alkanols preferably having 1 to 8 carbon atoms and their N-substituted derivatives, - amides of unsaturated carboxylic acids such as acrylamide, methacrylamide, N-methylolacryiamide or methacrylamide, N-alkylacrylamides, ethylenic monomers comprising a sulfonic acid group and its alkali or ammonium salts, for example acid vinylsulfonic, vinylbenzenesulfonic acid, alpha-acrylamido methylpropane-sulfonic acid, 2-sulfoethylene methacrylate, unsaturated ethylenic monomers having a secondary, tertiary or quaternary amino group, or a nitrogen-containing heterocyclic group such as by example vinylpyridines, vinylimidazole, aminoalkyl (meth) acrylates and aminoalkyl (meth) acrylamides such as dimethylaminoethyl-acrylate or dimethylaminoethyl-methacrylate, ditertiobutylaminoethyl-acrylate or ditertiobutylaminoethyl-methacrylate, dimethylaminomethylamethylethyl - methacrylamide, zwitterionic monomers such as, for example, sulfopropyl (dimethyl) aminopropyl acrylate, ethylenic monomers carrying a sulfate group, ethylenic monomers carrying phosphate or phosphonate functions, and their mixtures.

Preferably, the monomers used in the emulsion polymerization are mainly monomers

(meth) alkyl acrylates, present in an amount of 50% to about 99% and preferably in an amount of 80% to 99% by weight relative to the weight of monomers present in the emulsion.

These alkyl acrylate monomers preferably have 4 to about 8 carbon atoms in the alkyl chain.

More preferably, they are chosen at least from 2-ethylhexyl acrylate, butyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, iso acrylate -octyl, decyl acrylate, isobutyl acrylate, dodecyl acrylate, methacrylates such as n-butyl methacrylate, methacrylic acid, acrylic acid, itaconic acid, acid maleic and / or acrylide. Also suitable are adhesive compositions of the hot-melt type (photocrosslinkable or not), such as those described in US Pat. No. 5,536,772 and application WO 97/00300.

The PSAs suitable for the invention can in particular be obtained by emulsion polymerization by the radical route at atmospheric pressure and at a temperature generally between 10 and 90 ° C., of the corresponding monomers. Conventionally, this polymerization technique requires, in addition to the radical initiator, a mixture of anionic and / or nonionic emulsifiers to stabilize said emulsion. Likewise, the polymerization can be carried out in the presence of at least one monomer known as crosslinking agent. The emulsion polymerization of the monomers can be carried out in the presence of at least one radical initiator and, where appropriate, of a transfer agent, with a concentration of monomers of between approximately 20 and 75% by weight of the emulsion. The monomers can be introduced in the form of a preemulsion into the reaction medium. Any type of free radical initiator or initiator customary in emulsion polymerization may be suitable. Examples of initiators include hydroperoxides such as hydrogen peroxide, diisopropylbenzene hydroperoxide, sodium, potassium or ammonium persulfates, and cationic initiators such as azobis (isobutyronitrile) 4-4'azobis (4-cyano valeric acid). The amount of initiator (s) is generally between 0.05 and 2% by weight relative to the amount of the monomers. The additive according to the invention can be introduced at the end of this polymerization, that is to say in the final emulsion or in the hot-melt, before or immediately before its use, as an adhesive component for the preparation of a silicone / adhesive complex. As regards the silicones which may be associated with the adhesive, they derive from the crosslinking and / or polymerization of monomer (s), oligomer (s) or polymer (s) of organopolysiloxane nature. The nature of these monomer (s), oligomer (s) or polymer (s) can vary widely. Their activation mode, namely thermal, photochemical or electron beams, is selected according to the family of siloxanes used.

As regards more particularly the monomer (s), oligomer (s) and polymer (s) of organopolysiloxane nature which can be crosslinked cationically, thermal activation, UV and / or electron beam, they generally consist of units of formula ( I) and terminated with units of formula (II) or cyclic units consisting of units of formula (I) represented below:

R ¹ R1

-4-Si-0- - (I) _Z Si-0 (H)

R2

in which: the symbols R ¹ and R ² are similar or different and represent: - a linear or branched alkyl radical containing 1 to 8 carbon atoms, optionally substituted by at least one halogen, preferably fluorine, the alkyl radicals being of preferably methyl, ethyl, propyl, octyl and 3,3,3-trifluoropropyl, a cycloalkyl radical containing between 5 and 8 cyclic carbon atoms, optionally substituted, ^• an aryl radical containing between 6 and 12 carbon atoms which may be substituted, preferably phenyl or dichlorophenyl,

^• an aralkyl part having an alkyl part containing between 5 and 14 carbon atoms and an aryl part containing between 6 and

12 carbon atoms, optionally substituted on the aryl part by halogens, alkyls and / or alkoxyls containing 1 to 3 carbon atoms,

- the symbols Z are similar or different and represent: ^• a group R ¹ and / or R ² ,

^• a hydrogen radical,

^• and / or a crosslinkable organofunctional group, preferably epoxy and / or alkenyl ether and / or oxetane and / or dioxolane, linked to the silicon of the polyorganosiloxane via a divalent radical containing from 2 to 20 carbon atoms and which may contain at least one heteroatom, preferably oxygen,

^• with at least one of the symbols Z representing a crosslinkable functional organic group. According to an advantageous variant of the invention, the polyorganosiloxanes used comprise from 1 to 10 organofunctional groups per macromolecular chain. For an epoxyfunctional group, this corresponds to epoxide levels varying from 20 to 2000 meq. molar / 100 g of polyorganosiloxane. The linear polyorganosiloxanes can be oils of dynamic viscosity at 25 ° C, of the order of 10 to 10,000 mPa.s at 25 ° C, generally of the order of 50 to 5,000 mPa.s at 25 ° C and , more preferably still, of 100 to 600 mPa.s at 25 ° C, or gums having a molecular mass of the order of 1,000,000.

When cyclic polyorganosiloxanes are involved, these consist of units (I) which can be, for example, of the dialkylsiloxy or alkylarylsiloxy type. These cyclic polyorganosiloxanes have a viscosity of the order of 1 to 5000 mPa.s.

As examples of divalent radicals linking an organofunctional group of the epoxy type, mention may be made of those included in the following formulas:

(CH H ₂

With regard to organofunctional groups of the alkenyl ether type, mention may be made of those contained in the following formulas:

(O) _n (CH ₂ ) - 0-CH = CH ₂ _ (O) _n - (CH ₂ ) - R ³ - O-CH = CH ₂ ;

(O) _n , (CH ₂ ) - O-CH = CH -R ⁴

in which :

• n 'represents 0 or 1 and n "an integer between 1 and 5

• R ³ represents: a linear, branched or cyclic C 1 -C ₁₂ alkylene radical, optionally substituted,

- or a C ₅ -C ₁₂ arylene radical, preferably phenylene, optionally substituted, preferably with one to three CC ₆ alkyl groups,

• R ⁴ represents a linear or branched C ₆ -C ₆ alkyl radical.

The epoxy or alkenyl etherfunctional polyorganosiloxanes are generally in the form of fluids having a viscosity at 25 ° C of 10 to 10,000 mm ² / s and preferably from 100 to 600 mm ² / s. The dynamic viscosity at 25 ° C. of all the silicones considered in the present description can be measured using a BROOKFIELD viscometer, according to the AFNOR NFT 76 102 standard of February 1972.

This type of compound is described in particular in DE-A patents No. 4,009,889; EP-A- No. 396,130; EP-A- No. 355.381; EP-A- No. 105.341; FR-A- No. 2.110.115; FR-A- 2.526.800.

The alkenyl etherfunctional polyorganosiloxanes can be prepared by hydrosilylation reaction between oils with Si-H units and vinyloxyfunctional compounds such as allylvinylether, allyl-vinyl oxyethoxybenzene ... The functional epoxy polyorganosiloxanes can be prepared by hydrosilylation reaction between oils with Si-H units and epoxyfunctional compounds such as vinyl-4 cyclohexeneoxide, allylglycidylether ...

The silicones which best meet the object of the invention are described below and have at least one epoxide, alkenyl ether or oxetane group.

In the formulas below X can represent an alkyl group; cyclohexyia; trifluoropropyl; perfluoroalkyl; alkoxy or hydroxypropyl, R a hydrogen atom; or an alkyl or cycloalkyl group; alkenyl or alkenyl and (O≤a≤lOOO); (1≤b≤1000)

S3

S4

CH, CH ₃

I

(CH,), SI-0l -Si-0 -Si-O- -Si (CH ₃

I

CH, a O S11 n

S12

S13

S14

Other crosslinkable and / or polymerizable silicones by thermal activation derive more particularly from polyorganosiloxanes A having per molecule at least one reactive radical Si-H and free of silicon atom bonded to more than two hydrogen atoms and of chosen compounds B preferably from polyorganosiloxanes and having, per molecule, at least one reactive unsaturated aliphatic group and / or at least one reactive function.

Advantageously, the compounds A are chosen from polyorganohydrogensiloxanes comprising:

^{* units} of the following formula: H _a W _b SiO ₄ . _{(a + b)} ()

2 in which: - the symbols W are similar or different and represent a monovalent hydrocarbon group, preferably chosen from (cyclo) alkyl groups having from 1 to 18 carbon atoms included and, advantageously, from methyl, ethyl, propyl, octyl groups and 3,3,3-trifluoropropyl as well as from C ₆ -C ₁₂ aryl or aralkyl groups and, advantageously from xylyl and tolyl and phenyl radicals, all of these groups being optionally halogenated (fluorine for example) and or hydroxylated and / or alkoxylated. - a is 1 or 2, b is 0, 1 or 2, with the sum (a + b) having a value between 1 and 3,

* and possibly other reasons of medium formula:

WcSi0 ₄ . _c (2)

2 in which W has the same meaning as above and c has a value between 0 and 3.

Organopolysiloxane A can only be formed of unit of formula (1) or additionally comprise units of formula (2).

It can have a linear structure, branched or not, cyclic or networked. The degree of polymerization is greater than or equal to 2. More generally, it is less than 5000.

Examples of units of formula (1) are:

H (CH ₃ ) Si0 _1/2 , l-KChySiO, H ^ H ^ SiO ^.

When linear polymers are involved, these essentially consist of units “D” W ₂ Si0 _2/2 , WHSi0 _2/2 , and “M” W ₃ Si0 _1/2 , WH ₂ Si0 _1/2 ; the blocking terminal “M” units which may be thalkylsiloxy or dialkylarylsiloxy groups. Examples of terminal "M" units that may be mentioned include trimethylsiloxy, dimethylphenylsiloxy, dimethylethoxysiloxy, dimethylethylt ethoxy-silylsiloxy groups, etc.

By way of example of “D” units, mention may be made of dimethylsiloxy, methylphenylsiloxy groups.

These linear polyorganosiloxanes can be oils of dynamic viscosity at 25 ° C of the order of 1 to 100,000 mPa.s at 25 ° C, generally of the order of 10 to 5,000 mPa.s at 25 ° C, or gums having a molecular mass of the order of 1,000,000. When it is a cyclic polyorganosiloxane, these consist of units "D" W ^ SiO ^, and WHSi0 _2/2 , which can be of the type dialkylsiloxy or alkylarylsiloxy. They have a viscosity of the order of 1 to 5000 mPa.s.

The dynamic viscosity at 25 ° C. all the polymers considered in this presentation can be measured using a BROOKFIELD viscometer, according to the AFNOR NFT 76 102 standard of February 1972.

Examples of organopolysiloxanes A are:

dimethylpolysiloxanes with hydrogenodimethylsilyl ends, dimethylhydrogenomethylpolysiloxane copolymers with trimethylsilyl ends, dimethylhydrogenomethylpolysiloxane copolymers with hydrogenodimethylsilyl ends,

- hydrogenomethylpolysiloxanes with trimethylsilyl ends,

- cyclic hydrogenomethylpolysiloxanes. With regard to organopolysiloxanes B, namely having, per molecule, at least one reactive unsaturated aliphatic group and / or less a reactive function, they are preferably selected from polyorganosiloxanes comprising similar or different units of formula:

W ' _d X _e YSiO _4. ( _{D + e +} f) (3)

2 in which:

- the symbols W correspond to the same definition as that given above for W,

- the symbols X are similar or different and represent a hydrogen atom or a reactive function, preferably epoxyfunctional, linked to silicon by a divalent radical, for example C, -C ₂₀ , optionally comprising at least one heteroatom, the radicals X more particularly preferred being: 3-glycidoxypropyl, 4-ethanediyl (1, 2-epoxycylohexyl) ...,

the symbols Y are similar or different and represent a linear or branched alkenyl residue in C _r C ₁₂ , and having at least one ethylenic unsaturation at the chain end and / or in the chain and optionally at least one heteroatom;

- d, e and f are equal to 0, 1, 2 or 3; - d + e + f = 0, 1, 2 or 3; the rate of Si0 _{4/2 units} being less than 30 mol%.

As regards the Y residues, they are advantageously chosen from the following list: vinyl, propenyl, 3-butenyl, 5-hexenyl, 9 decenia, 10-undecenyl, 5.9-decadienyl, 6-1 1-dodecadienyl.

These organopolysiloxanes can have a linear structure (branched or not) cyclic or network. Their degree of polymerization is preferably between 2 and 5000. When linear polymers are involved, these essentially consist of units "D" V ^ SiO ^, XsiO ^, YsiO ^, and "M" W ₃ Si0 _1/2 , WYSiO _1/2 , W ₂ Xsi0 _1/2 , the terminal blocking "M" units can be trialkylsiloxy, dialkylarylsiloxy, dialkylvinylsiloxy, dialkylalkenylsiloxy groups. As examples of terminal "M" units, mention may be made of trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy, dimethylhexenylsiloxy, dimethylethoxysiloxy, dimethylethyltriethoxysiloxy groups.

By way of examples of units “D”, mention may be made of dimethylsiloxy, methylphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyidecenylsiloxy, methyldecadienylsiloxy, methyl-3-hydropropylsiloxy, methyl-3-propoxy-methyloxy-3-methyloxy-methyl-3-propoxy groups. , 4'- epoxycyclohexyl) ethylsiioxy, methylbutoxysiloxy, methyl-β- trimethoxysilylethylsiloxy, methyl-β-thethoxysilylethylsiloxy.

Said linear polyorganosiloxanes can be oils of dynamic viscosity at 25 ° C of the order of 1 to 100,000 mPa.s at 25 ° C, generally of the order of 10 to 5,000 mPa.s at 25 ° C, or gums with a molecular weight of the order of 1,000,000.

When cyclic polyorganosiloxanes are involved, these are constituted by "D" units W ^ iO ^, WSi0 _2/2 , WYSiO ^, which can be of the dialkylsiloxy, alkylarylsiloxy, alkylvinylsiloxy, alkylsiloxy, alkylXsiloxy type; examples of such patterns have already been cited above.

Said cyclic polyorganosiloxanes B have a viscosity of the order of 1 to 5000 mPa.s.

The compounds B with aliphatic unsaturation useful in the context of the process according to the invention are, for example, those with olefinic or acetylene unsaturation well known in the technical field considered. In this regard, reference may be made to the US patents 3,159,662, 3,220,272 and

3,410,886, which describe the above compounds. According to an advantageous variant of the invention, the reaction mixture comprises compounds A and compounds B in an amount such that the molar ratio Si-H / unsaturated groups and / or reactive function, that is to say epoxy, is between 0.4 and 10 preferably between 1 and 4 and, more preferably still, that is on the order of 1, 7.

The hydrosilylation reaction conditions by thermoactivation are the usual conditions. They are generally catalyzed by heat-sensitive platinum complexes. By way of illustration of these catalysts, mention may in particular be made of the KARSTEDT catalyst. The catalyst is present in an amount from 1 to 400, preferably from 10 to 300, and more preferably from 20 to 200 ppm of platinum metal expressed by weight relative to the polyorganosiloxane compound used.

In addition to this catalyst, the components of the silicone coating contain a reaction inhibitor. In fact, heat is used to deactivate this inhibitor and to allow crosslinking to start. Particularly suitable as an inhibitor, dialkyl carboxylic esters such as dialyly maleate or fumarate, α-acetylenic alcohols or hydroperoxides.

The complexes according to the invention may also contain other ingredients such as pigments, photosensitizers of fungicidal, bactericidal and antimicrobial agents, corrosion inhibitors, etc.

The quantities of coating deposited on the supports are variable. The amounts of silicone coating generally range between 0.1 and 5 g / m ² of treated surface. These amounts depend on the nature of the supports and on the desired non-stick properties. They are more often between 0.5 and 1.5 g / m ² for non-porous substrates. As regards the quantities of adhesive coating, preferably they are less than 200g / m ² and more preferably 100 g / m ^2.

The support can be chosen from metallic material such as cellulosic tinplate of paper or cardboard type for example, or from polymeric material of vinyl type. Thermoplastic polymer films such as polyethylene, polypropylene or polyester are particularly advantageous.

In the embodiment where the adhesive coating is in contact with a support made of a second material, this second material can be chosen from the materials offered for the first support and be of an identical nature or not to the first support.

Finally, the support on which the silicone coating and / or the adhesive coating is applied may already be coated with an initial coating to which the coating according to the invention is superimposed. It can thus be a sheet comprising a bitumen-type coating.

The present invention also relates to articles (ribbons for example) comprising a complex according to the invention. They may in particular be labels, self-adhesive sheets or adhesive tapes. A second aspect of the present invention relates to the use of an additive as defined above for stabilizing the release force of a silicone / adhesive complex as defined above by introduction of said additive into said adhesive coating .

The invention also extends to the use of an adhesive coating as defined above to form a silicone / adhesive complex according to the invention, characterized in that it contains at least one compound as defined above. above as an additive for stabilizing the release force at a silicone / complex interface. The examples which follow are presented by way of illustration and without limitation of the present invention.

Method

The compositions which are described in the following examples, based on the structural silicones (S1)

(S1)

Two polymers were chosen more particularly:

They respond to the average structure of random distribution such that

A ₁ / a = 80; b = 7 A ₂ / a = 222; b = 3

These silicones are photopolymerized, after application, on a polypropylene film of 50g / m ² . Is applied using a ^coating head comprising five rollers, a deposited silicone weight of which is between 0.5 and 1 g / m ² of plastic and 1 to 2 g / m ² of paper. The applied product is then exposed under ultraviolet irradiation at a running speed which varies between 50 and 1000 m / min, preferably greater than 100 m / min and in the presence of mercury vapor lamps sold by the company Fusion, power 120 W / cm or 240 W / cm and called H \ par preference over the nature of the radiation, which is mainly emitted between 200 and 300 m. The number of lamps used depends on the width of the width. A lamp occupies a width of 20 cm.

The number of lamps used depends on the speed of the process. A 120 W / cm lamp is enough to polymerize at 100 m / min. Two lamps will be effective for a process of 200 m / min or more.

After exposure to ultraviolet light, the coatings are perfectly dry and an acrylic adhesive 50% in water is applied, the base polymer of which has the following composition: P.,:> 70% in butyl acrylate and <25% in 2-ethyl hexyl acrylate

P ₂ :> 80% in 2-ethyl hexylacrylate and <10% in methyl methacrylate.

This application is carried out either online directly (10 to 20 g / m ² in dry) on an on-line or offline adhesion machine, after less than five minutes, after crosslinking of the functional silicones.

The adhesive is then heated to between 100 ° C and 150 ° C, preferably 100 ° C, for a time of less than 2 minutes so as to remove the water from the adhesive which is then transferred using a transfer cylinder on paper or plastic support. The detachment forces of the various complexes obtained are measured, after storage for 20 h at 20 ° C., according to a standardized test (FINAT3), under a force of 70 g / cm ² , with a detachment speed of 300 mm / min and after 20 hours at 70 ° C (FINA 10), simulating an aging of 3 and 6 months at 20 ° C under pressure conditions of 70g / cm ² .

Examples - 1 - 2

Use of additives added at 0.45% in the adhesive based on polymer P ₁ used without tackifier. The detachment forces of the adhesive applied in-line to the silicone deposited at the rate of 0.8 g / m ² on a polypropylene film are then measured, then dried at a rate of 200 m / min, using two 120 W / cm (H ⁺ ) Fusion lamps. The silicone formulation is obtained by mixing 95 parts of polymer A., with 2.5 parts of an 18% solution of the photoinitiator PI.,

in isopropanol and five parts of polymer A ₂ . The whole is shaken vigorously before use in the form of a coating bath on induction rollers.

The adhesive used, applied to the photocrosslinked silicone is based on the polymer P., and is marketed under the name RHODOTAK 315P. It is applied as an emulsion at around 50% dry extract (15-20 g / m ² ). The control test not comprising any additive in the adhesive is noted Additive 0. All the other additives used in the following examples are, at a rate of 0.45%, added directly to the emulsion adhesive with the exception potash which modifies the pH of the adhesive between 4 and 6 and which cannot be added to more than 1000 ppm.

The results obtained are presented in Table I below. Board

Examples 3-8 Examples with P., or P ₂ used with or without tackifier (25% Tacolyn 3179).

The polymer P ₂ used is mainly composed of basic units resulting from the polymerization of 2-ethyl acrylate, and marketed by BASF under the name Acronal V210. The silicone coating is applied in the same way as in the previous examples.

The adhesive is similarly dried at 100 ° C. in an oven before being transferred to a self-adhesive label backing paper.

The results obtained are presented in Table II below.

Table II

Examples 9-17

Examples 1 and 2 are repeated with the polymer P1, varying the quantity and the nature of the additives used. The silicone is applied to a polyester film at the rate of 0.8 g / m ² and the silicone is dried at 100 m / min with 1 "A" Fusion lamp of 120 W / cm.

Table III

EXAMPLES 18-26 Examples 9 to 17 are repeated, varying the support to which the silicone is applied at a rate of 1.5 g / m ² .

A coated paper sold by the company LOHTAN is used. Table IV

Examples 27-36

In this example, the following complexes of ethylene diamine tetra-acetic acid and carbonates were tested as additives:

- EDTA K ₃

- EDTANa ₄

- EDTA K ₂

- EDTA (NH ₄ ) ₂ - K ₂ C0 ₃

Variable amounts of additives are added, in the form of a 50% solution in demineralized water, in the adhesive based on the polymer P1 of the invention.

The adhesive used based on the polymer P., sold under the name RHODOTAK 315P and without tackifier, is applied as an emulsion with approximately 50% dry extract on the photocrosslinked silicone.

The silicone formulation is obtained by mixing 95 parts of polymer X with 2.5 parts of an 18% solution of photoinitiator P ^ in isopropanol and five parts of polymer A ₂ . The whole is agitated vigorously before use in the form of a coating bath on coating rollers.

The detachment forces of the adhesive applied in-line are measured on a silicone deposited at a rate of 0.8 g / m ² on a polypropylene film or 1.5 g / m ² on glassine paper sold by the company AHLSTROM or paper. coated marketed by LOHJAN; then dried at a rate of 200m / min using two Fusion lamps [240W / cm + 120W / cm (H ⁺ )] •

The control test not comprising any additive in the adhesive is denoted Additive 0.

Table V

Claims

1. Silicone / non-stick adhesive complex comprising at least one silicone coating applied to a first support and an adhesive coating applied to a second support, characterized in that said adhesive coating comprises as an additive intended to stabilize over time the release force of a silicone / adhesive interface at least one ammonium salt or of an element of group IA or IIA of the periodic table with a compound chosen from: - fluorophosphates

- fluorosulfonates,

- the esters or salts of phosphoric acid,

- mono or poly-carboxylates of formula R (COO) _n . with

- R representing a linear, branched or cyclic, saturated, unsaturated or aromatic C, to C ₁₂ alkyl group and optionally substituted by one or more halogen atoms and / or carboxylic function and / or the hydrocarbon chain of which may be interrupted by one or more oxygen, sulfur and / or nitrogen atoms, - n representing an integer between 1 and 6, preferably between

1 and 4 and

- with in the case of several carboxylate functions, the possibility for these to be positioned on the same atom or atoms distinct from the alkyl group represented by R and preferably at the end (s) of the linear or branched hydrocarbon chain represented by R.

2. Complex according to claim 1, characterized in that the mono- and poly-carboxylates are chosen from monocarboxylates, diacid carboxylates, polyacid carboxylates such as polyacrylic and / or polyamides or polyamines.

3. Complex according to claim 1 or 2, characterized in that the additive is chosen from:

- the carboxylates of formula R'COO ^θ , with R 'representing a linear, branched or cyclic, saturated, unsaturated or aromatic C 6 to C ₁₂ alkyl radical and optionally substituted by one or more halogen atoms, - - EDTA salts such as EDTA K ₃ , EDTANa _4, EDTA K ₂ and

EDTA (NH ₄ ) ₂

- fluorophosphates such as potassium hexafluorophosphate,

- fluorosulfonates such as potassium trifluoromethanesulfonate, and - esters or salts of phosphoric acid such as K ₃ P0 ₄ , K ₄ P ₂ O ₇ ,

(Me ₃ SiO) - POK with n '= 1 or 2, HK ₂ PO ₄ , KH ₂ P0 ₄ .

I o

4. Complex according to one of claims 1 to 3, characterized in that the first support and the second support consist of two separate materials and arranged so that the silicone coating of the first support is in contact with the adhesive coating of the second support.

5. Complex according to one of claims 1 to 3, characterized in that the first support and the second support consist respectively of each of the two faces of the same material.

6. Complex according to one of claims 1 to 5, characterized in that the additive is chosen from (C ₂ H ₅ ) (C ₄ H ₉ ) CHCOOK, (CH ₃ ) (CH ₂ ) ₇ CH = CH ( CH ₂ ) ₇ COOK, (CH ₃ COO) ₂ Ca, CH ₃ -COOK, (CH ₃ O) ₂ P (O) CH ₂ COOK, CF ₃ COOK, salts EDTA K ₃ , EDTANa ₄ EDTA K _2, EDTA (NH ₄ ) ₂ , K ₂ C0 ₃ and HK ₂ PO ₄ .

7. Complex according to one of claims 1 to 6, characterized in that the additive is present in the adhesive up to 5% by weight.

8. Complex according to claim 7, characterized in that the amount of additive varies between 0.01% and 1% by weight.

9. Complex according to one of the preceding claims, characterized in that the adhesive coating derives from a pressure-sensitive adhesive emulsion, PSA.

10. Complex according to claim 9, characterized in that the pressure-sensitive adhesive emulsions are obtained by polymerization mainly of acrylate monomers present in an amount of 50 to about 90% and preferably in an amount of 80 to 99% by weight and the optionally of copolymerizable radical monomers.

11. Complex according to claim 10, characterized in that the monomers are chosen from the group consisting of: - (meth) acrylic esters such as the esters of acrylic acid and methacrylic acid with C- alkanols | C ₁₂ hydrogenated or fluorinated, preferably CC ₈ , in particular methyl acrylate, acrylate ethyl, propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, tert-butyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, iso-octyl acrylate, decyl acrylate, dodecyl acrylate, methyl methacrylate, ethyl methacrylate, n methacrylate -butyl, isobutyl methacrylate; vinyl nitriles including more particularly those having 3 to 12 carbon atoms, such as in particular acrylonitrile and methacrylonitrile; vinyl esters of carboxylic acid such as vinyl acetate, vinyl versatate, vinyl propionate, ethylenic unsaturated mono- and dicarboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and the mono- and di-alkyl esters of these mono- and di-carboxylic acids with alkanols preferably having 1 to 8 carbon atoms and their N-substituted derivatives, amides of carboxylic acids unsaturated, such as acrylamide, methacrylamide, N-methylolacrylamide or methacrylamide, N-alkylacrylamides, ethylenic monomers comprising a sulfonic acid group and its alkali or ammonium salts, for example vinylsulfonic acid, vinylbenzenesulfonic acid, l alpha-acrylamido methylpropane-sulfonic acid, 2-sulfoethylene methacrylate, unsaturated ethylenic monomers having a secondary, tertiary or quaternary amino group, or a hetero group nitrogen containing erocyclic such as for example vinylpyridines, vinylimidazole, aminoalkyl (meth) acrylates and aminoalkyl (meth) acrylamides such as dimethylaminoethyl acrylate or dimethylaminoethyl- methacrylate, ditertiobutylaminoethyl-acrylate or ditertiobutylaminoethyl-methacrylate, dimethylaminomethyl-acrylamide or dimethylaminomethyl-methacrylamide, zwitterionic monomers such as, for example, sulfopropyl (dimethyl) aminopropyl acrylate, ethylenic monomers bearing ethylenic monomers bearing ethylenic monomers bearing phosphate or phosphonate functions, - and mixtures thereof.

12. Complex according to one of claims 10 or 1 1, characterized in that the monomers are chosen from 2-ethylhexyl acrylate, butyl acrylate, hexyl acrylate, heptyl acrylate , octyl acrylate, iso-octyl acrylate, decyl acrylate, isobutyl acrylate, dodecyl acrylate, methacrylic acid, acrylic acid, itaconic acid , maleic acid and acrylamide.

13. Complex according to one of the preceding claims, characterized in that the silicone coating is derived from the polymerization and / or crosslinking of monomers, oligomers and / or polyorganosiloxane polymers containing organofunctional groups.

14. Complex according to claim 12, characterized in that the monomers, oligomers and / or polymers of polyorganosiloxane nature have, as organofunctional groups, epoxy, oxetane, dioxolane and / or alkenyl ethers groups.

15. Complex according to claim 13 or 14, characterized in that the polyorganosiloxane monomers, oligomers and / or polymers with organofunctional groups consist of units of formula (I) and terminated by units of formula (II) or cyclic units of units of formula (I) shown below:

in which: the symbols R ¹ and R ² are similar or different and represent: - a linear or branched alkyl radical containing 1 to 8 carbon atoms, optionally substituted by at least one halogen,

^• a cycloalkyl radical containing between 5 and 8 cyclic carbon atoms, possibly substituted,

^• an aryl radical containing between 6 and 12 carbon atoms which may be substituted,

^• an aralkyl part having an alkyl part containing between 5 and 14 carbon atoms and an aryl part containing between 6 and 12 carbon atoms, optionally substituted on the aryl part by halogens, alkyls and / or alkoxyls containing 1 to 3 carbon atoms,

^• a hydrogen radical,

^• and / or a crosslinkable organofunctional group, such as oxetane, dioxolane, epoxy and / or alkenylether, linked to the silicon of the polyorganosiloxane via a divalent radical containing from 2 to 20 carbon atoms and which may contain at least one heteroatom ,

^• with at least one of the symbols Z representing a crosslinkable functional organic group.

16. Complex according to claim 15, characterized in that the divalent radicals connecting an organofunctional group of the epoxy type are chosen from:

(CH ₂ ) ₃ O - CH ₂ - CH CH ₂ ; (CH ₂ ) ₃ O - CH- -CH ₂

and the organofunctional groups of the alkenylether type are chosen from: (O) _n (CH ₂ ) - O-CH = CH ₂ (0) _n (CH ₂ ) - R ³ - O-CH = CH ₂ ; (0) _n , ₍ CH ₂ ) _n τr— O-CH = CH -R:> 4 in which :

• n 'represents O or 1 and n "an integer between 1 and 5

• R ³ represents:

a linear, branched or cyclic C 1 -C ₁₂ alkylene radical, optionally substituted,

• R ⁴ represents a linear or branched C ₆ -C ₆ alkyl radical.

17. Complex according to one of claims 1 to 12, characterized in that the silicone coating is derived from the crosslinking and / or polymerization of polyorganosiloxanes A having per molecule at least one reactive radical Si- H and free of bonded silicon atom with more than two hydrogen atoms and of compounds B chosen from polyorganosiloxanes and having per molecule at least one reactive unsaturated aliphatic group and / or at least one reactive function.

18. Complex according to claim 17, characterized in that the compounds A are chosen from polyorganohydrogenosiloxanes comprising:

* reasons for the following formula:

H _a W _b SiQ ₄ - _{(a + b) (1)}

2 in which: the symbols W are similar or different and represent a monovalent hydrocarbon group, chosen from the groups (cyclo) alkyls having from 1 to 18 carbon atoms included and the C ₆ -C ₁₂ aryl or aralkyl groups, and

- a is 1 or 2, b is 0, 1 or 2, with the sum (a + b) having a value between 1 and 3.

19. Complex according to claim 17 or 18, characterized in that the organopolysiloxanes A are chosen from:

- hydrogenomethylpolysiloxanes with trimethylsilyl ends,

- cyclic hydrogenomethylpolysiloxanes.

20. Complex according to one of claims 17 to 19, characterized in that the organopolysiloxanes B are polyorganosiloxanes comprising similar or different units of formula:

W ' _d XeYfSiO _4. (D ₊ e + f) (3)

2 in which:

the symbols W ′ correspond to the same definition as that given in claim 16,

- the symbols X are similar or different and represent a hydrogen atom or a reactive function, preferably epoxyfunctional, linked to silicon by a divalent radical, optionally comprising at least one heteroatom,

- the symbols Y are similar or different and represent a linear or branched alkenyl residue at C., - C ₁₂ , and having at least one ethylenic unsaturation at the chain end and / or in the chain and optionally at least one heteroatom;

- d, e and f are equal to 0, 1, 2 or 3;

- d + e + f = 0, 1, 2 or 3; with the rate of SiO _{4ι2 units} being less than 30% by moles.

21. Complex according to one of claims 17 to 19, characterized in that the silicone matrix comprises compounds A and compounds B in an amount such as the molar ratio Si-H / unsaturated group and / or reactive function, for example epoxy , is between 0.4 and 10, and preferably between 1 and 4.

22. Complex according to one of claims 17 to 21, characterized in that the silicone matrix further comprises a catalyst of the heat-sensitive complex type of platinum.

23. Article characterized in that it comprises a complex according to one of the preceding claims.

24. Article according to claim 23, characterized in that they are labels, self-adhesive sheets or adhesive tapes.

25. Use in an adhesive coating as defined in claims 1 and 9 to 13 and intended to form a silicone / adhesive complex according to one of claims 1 to 22 of a compound according to one of claims 1 to 8 for stabilize over time the release force of a silicone / adhesive interface.