WO1995025735A1

WO1995025735A1 - Platinum complexes and light-activatable hydrosilylation catalysts containing same

Info

Publication number: WO1995025735A1
Application number: PCT/FR1995/000329
Authority: WO
Inventors: Gérard Mignani; Théo MAYER
Original assignee: Rhone Poulenc Chimie
Priority date: 1994-03-18
Filing date: 1995-03-17
Publication date: 1995-09-28
Also published as: FR2717481A1; EP0750624A1; FI963669A0; FR2717481B1; CA2185824A1; FI963669A

Abstract

Novel platinum-based organometallic complexes for use particularly as a hydrosilylation cross-linking catalyst for Si-H type polyorganosiloxanes (A) and aliphatically unsaturated and/or reactive-functional compounds (B). Said complexes are of formulae (Ia) and (Ib), wherein R?1=R2=R3=CH¿3= and R4=R5=H. Light-cross-linkable compositions containing polyorganosiloxanes (A) and (B) and catalysts including the above-mentioned complexes are disclosed. The complexes are useful in a non-stick silicone coating for paper.

Description

PLATINUM COMPLEXES AND PHOTOACTIVABLE HYDROSILYLATION CATALYSTS CONTAINING THE SAME

TECHNICAL AREA :

The present invention relates to the field of catalysis of crosslinking reactions between polymer chains, e.g. silicones, comprising reactive radicals capable of forming interchain bridging, so as to obtain a crosslinked material having a certain hardness and a certain mechanical strength.

It is more particularly question, in the present description, of substrates to be crosslinked of polyorganosiloxane type A having, per molecule, at least one reactive radical Si-H, while being free of silicon atoms bonded to more than two atoms of hydrogen. These substrates A are intended to react with substrates of type B having, per molecule, at least one reactive unsaturated aliphatic group and / or at least one reactive function, eg epoxide, in the presence of a catalyst comprising at least one platinum complex, such a reaction being initiated or activated by light rays, of wavelength, chosen, preferably, in the field of ultraviolet (UV). More precisely still, the present invention relates, first of all, to new organo-metallic complexes based on platinum useful in particular as crosslinking catalyst by hydrosilylation of polyorganosiloxanes A of Si-H type and of compounds B with aliphatic unsaturation and / or reactive function.

The present invention also relates to a crosslinking process in which the above-mentioned catalyst is used, as well as compositions which can be crosslinked by photoactivation and which contain, inter alia, the substrates A and B and the above-mentioned catalyst.

Among the applications that can be envisaged in the context of the invention, there may be mentioned, for example: coatings formed from a mixture of silicone oils which can be crosslinked together and which are intended to form non-stick layers on fibrous supports, such as paper, dental impressions, adhesives, sealants, jointing materials, etc. PRIOR ART:

For non-stick paper application, among others, cross-linking in situ by photoactivation, e.g. by UV irradiation, is particularly advantageous insofar as it allows high coating speeds. In addition, this in situ crosslinking can take place easily at room temperature. It also avoids the use of solvents, the elimination of which is costly and difficult.

One of the crucial elements in this photo¬ activation crosslinking technique is of course the photochemical catalyst. It is thus sought to develop inactive catalytic systems up to temperatures greater than or equal to room temperature (30-40 ° C) and this, for as long as possible. It goes without saying that these catalytic systems are also required to have a very high reactivity to the light rays considered.

Conventionally, these catalysts are in the form of organometallic complexes (platinum or the like).

In this field, it is possible to mention in particular FALTYNEK, which reports in "Inor. Chemistry., 20 (1981), 1357" of rhodium complexes active in the photocatalysis of hydrosilylation reactions. It appears that these rhodium complexes have relatively weak catalytic activities. Ultimately, platinum has proven to be the most suitable metal for entering into the composition of these organometallic complexes.

US Pat. Nos. 4,510,094 and 4,600,484 thus disclose organometallic complexes of platinum, as well as catalysts and processes for hydrosilylation using them, constituted by a cyclopentadienyl group bonded in η to the atom of platinum and by three other aliphatic groups linked in σ to Pt.

The reactions catalyzed by these compounds involve polyorganosiloxanes comprising silicon atoms bound to hydrogen and polyorganosiloxanes comprising aliphatic unsaturations, e.g. alkylene, preferably ethylenic.

One of the major drawbacks of this photoactivated catalysis is that the catalyst of the platinum type η cyclopentadienyl (Cp) σ-trialkyl is difficult to obtain.

Indeed, Cp, which is one of the starting products for the synthesis of this catalyst, can only be prepared from a dimer and by implementing drastic conditions: (- 40 ° C among others ). In addition, this ligand Cp can be considered as a particularly toxic product. Such a synthesis of Cp is disclosed in A. DAVIDSON and PE RAKITA, Inorg. Chem., 9 (1970), 289.

It follows that the photosensitive catalyst described in US Patents 4,510,094 and 4,600,484 suffers from the serious defect of being difficult to prepare industrially. Finally, these known catalysts and the processes using them have been found to be not very sensitive to the positive influence of molecular oxygen, which is however known as an agent making it possible to accelerate the kinetics of crosslinking of silicone oils Si-H / Si-alkenyl.

In this state of affairs, one of the essential objectives of the present invention is to provide new platinum complexes which are useful, in particular, as hydrosilylation catalysts, of Si-H type polyorganosiloxanes and of aliphatic unsaturated compounds (preferably ethylenic, eg Si-Vi) and / or of compounds with reactive polar functions:

- which are photoactivatable and possibly thermoactivable, - and which are efficient without sacrificing the imperatives of industrial feasibility and profitability.

Another objective of the invention is to provide a process for hydrosilylation by photoactivation of reactive products, and in particular of silicones, in which the abovementioned catalysts are used, said process having to be carried out easily, quickly. , and inexpensive.

Another objective of the invention is to propose a composition of silicone oils crosslinkable by photoactivation:

- which includes the above catalyst,

- which is stable up to temperatures above room temperature, preferably greater than or equal to 30-40 ° C, and this over long periods,

- and which is very reactive towards light radiation.

Such a system should thus be easily storable and usable, for example for paper anti-adhesion, dental impressions, sealing or jointing materials, adhesives, or for any other application in which it is advantageous to implement a in situ crosslinking of silicone elastomers.

PRESENTATION OF THE INVENTION:

The present invention thus relates to new platinum complexes of the following formula:

in which

Cy is one of the two cyclic residues (a) and (b) following Δ (a)

with

0 Z, Z 'identical or different from each other and selected from the following list of radicals:

D C1-C12 alkyl and alkoxy, linear or branched, D trialkylsilyl, aryl, aralkyl, arylalkoxyl, the alkyl parts of which are linear or branched Ci-Cβ and the aryl parts of which comprise 1 or 2 aromatic cyles, D the above radicals being optionally substituted, in particular perhalogenated, - NR'R "with R 'and R" identical or different and representing hydrogen, a linear or branched C1-C4 alkyl or a substituted or unsubstituted phenyl, 0 R ⁴ = H , alkyl, Δ (b)

with R ⁵ = H, alkyl;

1 3 - R, R, R are identical or different from each other and represent an aliphatic group having from 1 to 8 carbon atoms, the methyl, ethyl, propyl, pentyl, hexyl, allyl, acetyl, propionyl groups being preferred and the group methyl being very particularly preferred.

- x = 1 or 2. excluding the following complexes (I):

(1) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (Ia), R ⁴ = H, and Z = Z '= CH3

(2) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= (n) - C3H7 (3) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= CF3

(4) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ ≈ H, and Z = Z '= - O - CH3

(5) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= - O - C2H5

(6) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = CH3, Z '= - O - CH3

(7) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = CH3, Z '= - O - C2H5 (8) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = CH3, Z '= CF3

(9) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = CH3, Z '= phenyl

(10) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= C2H5

(11) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= / -ÎO-C3H7

(12) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= n-C4H9 (13) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= WO-C4H9

(14) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= n-C5Hι 1

The complex of formula (la) is preferably in the form of a dimer (x = 2) which can be diagrammed as follows:

According to a particularly advantageous form of the invention, the radicals Z and Z 'are of the same nature and R ¹ = R ² = R ³ = CH3 and R ⁴ = H.

The formula (la) is a symbolic representation covering the two tautomeric forms above:

As regards the complex (Ib), its preferred form according to the invention is that in which R ⁵ = H and R ¹ = R ² = R ³ = CH3:

(Ib)

It should be noted that the degree of oxidation of Platinum in these complexes is formally IV.

The present invention also relates to a hydrosilylation catalyst between, on the one hand, polyorganosiloxanes A having, per molecule, at least one reactive radical Si-H and free of silicon atom bonded to more than two atoms of hydrogen, and, on the other hand, compounds B having at least one reactive unsaturated aliphatic group and / or at least one reactive function, said catalyst being (thermo) photoactivatable and comprising at least one platinum complex chosen by the complexes of formula (la) and (Ib) described above, but without excluding complexes (1) to (14) mentioned above.

BEST WAY TO IMPLEMENT THE INVENTION:

Preferably, the radicals suitable for Z and Z ′, in the hydrosilylation catalysis application, are: Me; OEt; Ph; n-octyl; CF3, Et; O-SiMe, t-Bu (Me = Methyl, Et = Phenyl, Bu = Butyl).

The polyorganosiloxane compounds considered are chemical substances having specific molecular identities or are formed by mixtures of these substances. The catalyst according to the invention is particularly advantageous in the context of in situ silicone crosslinking techniques, in which compositions are used comprising both polymers intended to react with each other and a photosensitive catalytic system, so that it does not It is not necessary to mix at the time of application. In addition, this catalyst meets the requirements for stability at room temperature and high reactivity under the effect of light radiation, in particular d JV. This catalyst is indeed very efficient in hydrosilylation.

In addition, it should be noted that the photoactivable nature of the reactions in which this catalyst acts is particularly advantageous, in particular with regard to the savings in activation energy that this generates.

The catalyst according to the invention is also advantageous in that it makes it possible to obtain crosslinked elastomeric compositions with modular properties, eg: giving anti-adhesion to surfaces of substrates such as metal, glass, plastics and paper. Taking into account the various molecular identities that can be envisaged for the complexes (I) according to the invention, it must be considered that the catalyst of which it is a question in the present description, may consist of a mixture of complexes of formula (I), each contributing obtaining advantageous results specific to the invention. The synthesis of the platinum complexes according to the invention, which had hitherto never been used as photosensitive catalysts for hydrosilylation reactions could in no way be called complexity.

Regarding the compounds (la), this synthesis consists in reacting, e.g., the anion of β-diketoesters or of β-diketones on [I.Pt Me3] 4 as described by BRICE J.E. and Coll. in "J. S. Inorg. Chem., 28 (1989), 1".

The compounds (Ib) are prepared according to the procedure described above for (la), by reacting the anion (eg lithiated, potassium, sodium or thallic) of β-diketoesters or of β-diketones of tropolone on [I. Pt.Me3] 4, constituting the ligand Cy.

These syntheses of (la) and (Ib) therefore meet all the criteria useful for being considered as industrially feasible, especially since they are further characterized by good isolated yields (greater than or equal to 50%).

The photosensitive catalyst according to the invention is non-reducible, so that it does not tend to react with the reactive Si-Hs of type A polyorganosiloxanes.

According to another of these aspects, the present invention relates to a hydrosilylation process between, on the one hand, polyorganosiloxanes A having, per molecule, at least one reactive radical Si-H and free of silicon atoms bound to more than two hydrogen atoms, and on the other hand, compounds B preferably chosen from polyorganosiloxanes and having, per molecule, at least one unsaturated aliphatic reactive group and / or at least one reactive function, process in which one implements at least one platinum complex as a catalyst.

This process differs from its counterparts in that it consists essentially in reacting compounds A and B in the presence of a catalyst of the type of that in accordance with the invention described above, the initiation of the reaction being carried out by photoactivation.

Advantageously, the compounds A are chosen from polyorganohydrogensiloxanes comprising: * units of the following formula: H _a W _b SiO ₄ - _a + b) (1)

2

in which: the symbols W are similar or different and representing a monovalent hydrocarbon group, free of adverse action on the activity of the catalyst and preferably chosen from (cyclo) alkyl groups having from 1 to 18 carbon atoms included and, advantageously, from methyl, ethyl, propyl, octyl and 3,3,3-trifluoropropyl groups and also among the C6-C12 aryl or aralkyl groups and, advantageously, among the xylyl and totyl and phenyl radicals, all of these groups being optionally halogenated (eg fluorine) and / or hydroxylated and / or alkoxylated. - a is 1 or 2, b is 0, 1 or 2, the sum (a + b) has a value between 1 and 3,

* and possibly other reasons of medium formula:

W _c SiO ₄ - _c (2) 2 in which W has the same meaning as above and ca a value between 0 and 3.

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

Organopolysiloxane A can have a linear, branched or unbranched, cyclic or network structure. The degree of polymerization is greater than or equal to 2. More generally, it is less than 5,000.

Examples of units of formula (1) are:

H (CH ₃₎ SiOι / _2, HCH ₃ SiO _2/2, H (C ₆ H ₅₎ SiO _2/2 In the case of linear polymers, they are essentially composed-of "D" units W2Siθ2 / 2, WHSiθ2 / 2, and "M" W3SiOι / 2 or W2HSiOι / 2, WH2SiOι / 2; the blocking terminal "M" units can be trialkylsiloxy, dialkylarylsiloxy groups.

By way of example of terminal "M" units, mention may be made of trimethylsiloxy, dimethylphenylsiloxy, dimethylethoxysiloxy, dimethylethyltriethoxysilylsiloxy groups, etc.

As examples of units "D", mention may be made of dimethylsiloxy, methylphenylsiloxy groups.

Said linear polyorganosiloxanes A 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 from 10 to 5,000 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 "D" units W2Siθ2 / 2, and WHSiθ2 / 2, which can be of the dialkylsiloxy or alkylarylsiloxy type.

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

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

The viscosity in question in this presentation is the dynamic viscosity at 25 ° C called "Newtonian", that is to say the dynamic viscosity which is measured, in a manner known per se, at a shear rate gradient sufficiently low so that the viscosity measured is independent of the speed gradient.

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.

As regards compounds B, they are selected from polyorganosiloxanes comprising similar or different units of formula:

W _d X _e YfSiθ4 - _{(d + e + f)} (3) 2

in which :

Δ the symbols W correspond to the same definition as that given above for W, Δ 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 eg in C1-C20 optionally comprising at least one heteroatom, the more particularly preferred X radicals being: 3-glycidoxyρropyl, 4-ethanediyl (1,2-epoxyclohexyl), ..., Δ the symbols Y are similar or different and represent a linear or branched alkenyl residue in Ci -Ci 2 and having at least one ethylenic unsaturation at the end of chain and / or in the chain and optionally at least one heteroatom;

Δ d, e and f are equal to 0, 1, 2 or 3 and d + e + f = 0, 1, 2 or 3; the rate of Siθ4 / 2 units being less than 30% by mole;

According to an advantageous arrangement of the invention, the reactive polar functions are chosen from the following residues: hydrogen, epoxide, radicals in

As regards the Y residues, they are advantageously chosen from the following list: vinyl, propenyl, 3-butenyl, 5-hexenyl, 9-decenyl, 10-undecenyl, 5.9-decadienyl, 6,11-dodecadienyl.

Organopolysiloxanes B 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" W2Siθ2 / 2, Siθ2 / 2, YSiθ2 / 2, and "M" W3SiOι / 2, w ^" 2YSiOι / 2, ^" 2XSiOι / 2, the terminal blocking "M" units can be trialkylsiloxy, dialkylarylsiloxy, dialkylvinylsiloxy, dialkylalkenylsiloxy groups.

Examples of terminal "M" units that may be mentioned include trimethylsiloxy, dimethylphenylsiloxy, dimethylvinylsiloxy, dimethylhexenylsiloxy, dimethylethoxysiloxy, dimethylethyltriethoxysilylsiloxy groups, etc.

As examples of units "D", mention may be made of dimethylsiloxy, methylphenylsiloxy, methylvinylsiloxy, methylbutenylsiloxy, methylhexenylsiloxy, methyldecenylesiloxy, methyldecadienylsiloxy, methyl-3-hydroxypropylsiloxy, methyl-

3-glycidoxypropyl-siloxy, methyl-2 (3 ', 4'-epoxycyclohexyl) ethylsiloxy, methyl-butoxysiloxy, methyl-β-trimethoxysilylethylsiloxy, methyl-β-triethoxysilylethylsiloxy.

Said linear polyorganosiloxanes B 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 cyclic polyorganosiloxanes B, these consist of units "D" W2Siθ2 / 2, WSiθ2 / 2, WYSiθ2 / 2. which may be of the dialkylsiloxy, alkylarylsiloxy, alkylvinylsiloxy, alkylYsiloxy, 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.

Having this large variety of polyorganosiloxanes B, it is perfectly conceivable to use a mixture of different products of formula (3), as defined above. 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 can be made to US Patents 3,159,662, 3,220,272 and 3,410,886, which describe the above compounds.

According to an advantageous embodiment of the invention, the reaction mixture comprises compounds A and compounds B in an amount such that the Si-H molar ratio / unsaturated groups and / or reactive polar function is between 0.4 and 10, preferably between 1 and 4 and, more preferably still, of the order of 2.5 ± 0.5, the catalyst being present in an amount of 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 compounds A and B present.

The technical literature of the field considered gives all the other useful information, as for the reaction conditions of hydrosilylation by photoactivation (A / B mixture and UV irradiation at 25 ° C).

Although the catalyst according to the invention is sufficiently reactive and efficient to dispense with the use of photosensitizers, it is entirely possible, for the sake of optimization, to use such products.

Thus, in accordance with a variant of the invention, at least one photosensitizer is provided having a triplet energy greater than or equal to 31 Kcal / mole and selected from (poly) aromatic (optionally metallic) and heterocyclic products, preferably in the following list of products: toluene, pyridine, ferrocene, benzene, thioxanthone, anthracene, benzophenone, this selection being made so that the triplet lifetimes of the platinum complexes and of the photosensitizer (s) are preferably of the same order. ^• 5

Advantageously, these photosensitizers are used at a rate of 5 × 10 to 5%, preferably 0.5 to 1.5 and, more preferably still, approximately 1% by weight relative to the weight of the compounds A and B used.

For more details on these photosensitizers, reference is made to patent application EP 0358452.

The crosslinking reactions of silicone oils, in particular hydrosilylation (e. G: Si-H / Si-Vi), catalyzed by photosensitive complexes of platinum, such as those according to the invention, pass through the formation of particles. colloids, useful as a support for platinum, according to a heterogeneous catalysis process. The Applicant has had the merit of demonstrating that the addition of at least one surfactant in the reaction medium allows stabilization of the above-mentioned colloidal particles and therefore an optimization of the catalysis of the crosslinking reaction by the complex according to the invention.

The surfactant is preferably a quaternary ammonium salt, such as tetraoctylammonium bromide, which is an example of a particularly preferred compound.

Advantageously, this surfactant is present in the reaction medium in a proportion 2 to 15 times, preferably from 5 to 10 times the molar amount of platinum-metal.

According to a remarkable method of the invention, it is planned to introduce molecular oxygen into the reaction medium before photoactivation, which has positive repercussions on the crosslinking kinetics.

As already indicated above, photoactivation preferably takes place in the ultraviolet range.

The fact of coupling this photoactivation to a thermoactivation can constitute another factor further improving the performance of the process according to the invention. This thermoactivation is preferably carried out using infrared radiation and it takes place advantageously after the photoactivation.

A last aspect of the invention, which is mentioned in a nonlimiting manner in the present description, relates to a crosslinkable and in particular photocrosslinkable composition, characterized in that it comprises the compounds A and B, and a catalyst as defined above.

The amounts by weight of compounds A and B and of the catalyst are also given above.

As can be deduced from the above, the above composition can also comprise at least one photosensitizer having an energy of triplet greater than or equal to 31 Kcal / mole and selected from (poly) aromatic (possibly metallic) and heterocyclic products, and preferably from the following list of products: toluene, pyridine, ferrocene, benzene, thioxanthone, anthracene, benzophenone, this selection being made so that the lifetime in triplet state of the organometallic complexes of platinum and of the photosensitizer (s) are advantageously of the same order.

In addition, it is preferable that this composition includes among these constituents at least one surfactant, said agent preferably being a quaternary ammonium salt, tetraoctylammonium bromide being particularly preferred, knowing that the surfactant is present in the medium reaction at a rate of 2 to 15 times, preferably 5 to 10 times the molar amount of platinum-metal.

These compositions in accordance with the invention are prepared either before (or even long before) or even immediately before the implementation of the hydrosilylation process. It should be noted that these compositions are particularly stable on storage and that they offer, in accordance with the process of the invention, rapid crosslinking kinetics. In addition, their uncrosslinked state, before exposure to the activation light radiation, offers great ease of handling, application or placement on different supports or other shaping molds. Conventionally, the compositions and / or the method according to the invention can incorporate different additives, chosen according to the intended final application. It can be, for example, minimum or non-filler and / or pigments such as ground synthetic or natural fibers (polymers), calcium carbonate, talc, clay, titanium dioxide or silica. This can improve e. g. the mechanical characteristics of the final materials.

Soluble dyes, oxidation inhibitors and / or any other material which does not interfere with the catalytic activity of the platinum complex and does not absorb in the wavelength range chosen for photoactivation, can also be added. to the composition or used in the context of the process according to the invention.

Among the other known and available additives which could be used, mention may be made of catalyst inhibitors, such as for example certain polyolefinic siloxanes, pyridine, organic phosphites and phosphines, unsaturated amides, alkylated maleates, acetylenic alcohols (cf. FR-Bl 528 464 and FR-A-2372874). These acetylenic alcohols inhibiting hydrosilylation reaction can have the formula:

R ⁷ - (R ⁸ ) C (OH) - C ≡ CH formula in which, η. R is a linear or branched alkyl radical, or a phenyl radical; . R 8 is H or a linear or branched alkyl radical, or a phenyl radical; the radicals R 7, R 8 and the carbon atom located at α of the triple bond which can optionally form a ring; the total number of carbon atoms contained in R 7 and R 8 being at least 5, preferably from 9 to 20.

Said alcohols are preferably chosen from those having a boiling point above 250 ° C. Mention may be made, by way of example:

. ethynyl-1-cyclohexanol 1;

. 3-methyl-dodecy-1 ol-3; . trimethyl-3,7,11 dodécyne-1 ol-3;

. diphenyl-1,1 propyne-2 ol-1;

. 3-ethyl-6-ethyl nonyne-1 ol-3;

. 3-methyl-pentadecyne-1 ol-3.

These α-acetylenic alcohols are commercial products. These inhibitors, also known as thermal blockers, make it possible to increase the "pot life" of the compositions considered (stabilities greater than 3-5 days), without harming the kinetics of hydrosilylation.

Once prepared by mixing all the above-mentioned compounds, the composition can be applied, for various purposes, to the surface of any solid substrate. These solid supports can be paper, cardboard, wood, plastic (e.g. polyester, nylon, polycarbonate), fibrous supports woven or not made of cotton, polyester, nylon etc, or a metal, glass or ceramic.

POSSIBILπΕ OF INDUSTRIAL APPLICATION:

The applications, more particularly, targeted by the catalyst, the process and the compositions according to the invention are, in particular, those of cross-linkable silicone oils "in situ", useful for the preparation of non-stick coatings on fibrous supports of any kind and in particular on paper. In this application, the above compositions allow very high coating speeds to be achieved, due to their very rapid crosslinking kinetics.

Other possible applications are, for example, dental impression materials, adhesives, sealants, sealants, adhesion primers.

The following examples of catalysts, compositions and implementations of the process according to the invention will allow a better understanding of the latter and will provide an illustration of its advantages and of its variants.

EXAMPLES

EXAMPLE 1: SYNTHESIS OF THE COMPLEXES (IA) AND (IB) OF THE PLATINUM (IV)

ACCORDING TO THE INVENTION.

The procedure used is identical to that described in the literature, for example:

[1] BRICE.J et al., Inorg. Chem., 25 (1986) 2181, [2] KITE K et al., J. Organometal.Chem., 44J. (1992) 159, [3] HAZELL et al., Proc.Roy.Soc, 254 (1960) 218, [4] MENZIES.R et al., J. Chem. Soc, (1949) 1168.

OPERATING MODE:

Is introduced into 20 ml of dry toluene, 2.80 mmol of Z-CO-CH2-CO-Z or the tropolone and 2.80 mmol of TlOEt. 0.7 mole of [I-PtMe3] 4 prepared according to the method described by CLEEG.D [Inorg. Synth., 10 (1967) 71]. The reaction medium is left to react for 30 min at 90 ° C. After filtration and evaporation of the solvent under vacuum pump, a solid is recovered which is recrystallized from an ether-pentane mixture (75/25, V / V).

For the case where Z = n-Octyle an orange oil is obtained. The complexes are then dried under a vacuum pump (1 mm dΗg) for 24 h at 25 ° C. For the preparation of the complexes (la), it is also possible to use a technique according to which lithiated or soda salts are used, of the type:

with M = Na, Li. See G. RAO et al, "Advances in organometallic chemistry", vol 27, p. 113. Table I below collates the results obtained.

TABLE I

All these complexes have been characterized by IR, NMR and Mass Spectrography (EI).

EXAMPLE 2: KINETICS OF HYDROSILYLATION OF Si-H AND Si-Vi OILS UNDER UV IRRADIATION.

OPERATING CONDITIONS:

The disappearance of the Si-H vibration band as a function of time is measured by FTIR for different catalysts. The complex to be studied is introduced before UV irradiation into the silicone oil with Si-Vi units, then the silicone oil with Si-H unit is added. These silicone oils have the following structures: Silicone oil with Si-H units: Me3Si- (SiMe2θ) i5 _j 6- (SiMeHO) 82-SiMe3, 3 mol% of Si-H units.

Silicone oil with Si-Vi patterns: ViSiMe2θ- (SiMe2θ) 97-SiMe2Vi. The measurements are carried out at 25 ° C. The film thickness is 24 μm. The mixture of silicone oils has a Si-H / Si-Vi molar ratio = 1.7. UV irradiation is obtained by a low pressure mercury lamp, HPK 125, power: 70 mj / cm .min, λ = 200-600 nm.

Fig. 1 below represents the different kinetics observed for different Pt (IV) catalysts. On the abscissa: duration of irradiation, on the ordinate: variation of the Si-H patterns, arbitrary units. The various catalysts tested are of the type (la): [(Z-CO-CH-CO-Z) PtMe3] 2:

(A): Z = Me (284 ppm Pt / total mass)

(B): Z = O-Et (279 ppm Pt / total mass) (C): Z = Ph (256 ppm Pt / total mass)

(D): Z = Et (323 ppm Pt / total mass)

(E): Z = n-Octyl (240 ppm Pt / total mass)

(F): Z = CF3 (260 ppm Pt / total mass)

EXAMPLE 3: MEASUREMENT OF THE THERMAL GEL TIME.

The thermal gel time is determined at 25 ° C. The platinum complex to be studied is introduced into the silicone oil with Si-Vi units, then the oil with Si-H units is added. The silicone oils used are those described in Example 1. The Si-H / Si-Vi molar ratio is 1.7. The measurement is carried out protected from light. Table II below collates our results obtained with 100 ppm of Platinum relative to the total mass. TABLE π

EXAMPLE 4 ADDITION OF PHOTOSENSITIZERS.

Fig. 2 below brings together the results obtained with regard to the kinetics of hydrosilylation of a mixture of silicone oil Si-H / Si-Vi. The silicone oils used are identical to those described in Example 1. The Si-H / Si-Vi molar ratio is 1.7. The tests are carried out at 25 ° C under UV irradiation (medium pressure mercury lamp with a power of 80 W / cm). The catalyst used is [(EtO-CO-CH-CO-OEt) PtMe3] 2 (350 ppm platinum / total mass). The photosensitizers are introduced into the reaction mass at a rate of 1000 ppm / total mass. The film thickness is 24 μm.

* 4-methoxy-benzophenone; x (4.4 - Bis (dimethylamino) -benzophenone; D 2-Chlor-dibenzothioxanthenone;

• [(Me3Pt (diethylmalonate)] 2;

EXAMPLE 5 ADDITION OF AROMATIC SOLVENTS.

Fig. 3 below shows the influence of adding an amount of aromatic solvent such as toluene or pyridine for the hydrosilytation reaction of silicone oils Si-H / Si-Vi. First, add the platinum complex in the silicone oil with Si-Vi patterns. This mixture is added to a silicone oil with an Si-H motif. Finally, the aromatic compound is added (500 ppm total mass). The Si- H / Si- Vi molar ratio is 1.7. The tests are carried out at 25 ° C under UV irradiation (medium pressure mercury lamp with a power of 80 W / cm). The catalyst used is [(EtO-CO-CH-CO-OEt) PtMe3] 2 (350 ppm platinum / total mass). The film thickness is 24 μm. The solvents tested are: x toluene * pyridine;

• ([Me3Pt (diethylmalonate)] 2)

EXAMPLE 6: INFLUENCE OF THE QUANTITY OF CATALYST.

Fig. 4 below represents the influence of the amount of catalyst. The catalyst used is [(EtO-CO-CH-CO-OEt) PtMe3] 2 (200-500 ppm platinum / total mass). The film thickness is 24 μm. The tests are carried out at 25 ° C under UV irradiation (medium pressure mercury lamp with a power of 80 W / cm). The platinum complex is dissolved in a minimum of toluene and this solution is added to a silicone oil with Si-Vi patterns. This mixture is added to a silicone oil with an Si-H motif. The Si-H / Si-Vi molar ratio is 1.7.

EXAMPLE 7: INFLUENCE OF THE NATURE OF SILICON OILS.

Fig. 5 below represents the kinetics of hydrosilylation of a mixture consisting of a silicone oil with Si-H units and a silicone oil with alkenyl units, catalyzed by the [(ETO-CO-CH-CO-OEt) PtMe3 complex ] 2 (350 ppm platinum / total mass). The Si-H / Si-Alkenyl molar ratio is 1.7. The alkenyl patterned silicone oil has the following formula:

The test is carried out at 25 ° C under UV irradiation (medium pressure mercury lamp with a power of 80 W / cm). The film thickness is 24 μm. Fig. 6 below represents the kinetics of hydrosilylation of a mixture consisting of a silicone oil with Si-H units and a silicone oil with epoxy units, catalyzed by the PtMe3 complex [(EtO-CO-CH-CO-OEt) ] 2 (350 ppm platinum / total mass). The Si-H / Si-Alkenyl molar ratio is 1.7. The silicone oil with epoxy patterns has the following formula:

Me ₃ Si O- (SiMeO) - (SiMe ₂ O) - Si Me ₃

EXAMPLE 8 INFLUENCE OF THE ADDITION OF OXYGEN.

Fig. 7 below shows the influence of the addition of oxygen on the rate of hydrosilylation of a mixture of Si-H / Si-Vi silicone oils, catalyzed by the following platinum complex: [(EtO-CO -CH-CO-OEt) PtMe3] 2 (200 ppm platinum / total mass). The silicone oils used are those described in Example 1 in a Si-H / Si-Vi molar ratio of 1.7.

The catalyst is dissolved in a minimum of dry toluene and added to the silicone oil with Si-Vi units. Oxygen is then bubbled through this mixture (1 min, 25 ° C.) and the silicone oil with Si-H units is then introduced. The test is carried out at 25 ° C under UV irradiation (medium pressure mercury lamp with a power of 80 W / cm). The film thickness is 24 μm.

Curve Ci corresponds to the test with O2 and curve C2 constitutes the negative control without O2-

EXAMPLE 9 INFLUENCE OF THE ADDITION OF AMMONIUM SALT

Fig. 8 below represents the influence of the addition of an ammonium salt, for example BrN (n-Octyl) 4 (2000 ppm / total mass), in the reaction medium for hydrosilylation of silicone oils Si- H / Si- Vi. The silicone oils used are those described in Example 1. The catalyst used is the complex ((EtO-CO-CH-CO-OEt) PtMe3] 2 (350 ppm of platinum / total mass). The Si-H / SiVi molar ratio is 1.7. The test is carried out at 25 ° C under UV irradiation (medium pressure mercury lamp with a power of 80 W / cm). The film thickness is 24 μm. Legend to fig. 8: o = with (nBu) 4 N® Br®

• = catalyst only

Claims

CLAIMS:

1 - Platinum complexes of the following formula

in which :

- Cy is one of the two cyclic residues (a) and (b) following Δ (a)

with:

D C1-C6 alkyl and alkoxyls, linear or branched, D trialkylsilyl, aryl, aralkyl, arylalkoxyl, the alkyl parts of which are linear or branched Ci-Cό and the aryl parts of which comprise 1 or 2 aromatic cyles, D the above radicals being optionally substituted, in particular perhalogenated,

* - NRΕ. "With R 'and R" identical or different and representing hydrogen, a linear or branched C1-C4 alkyl or a substituted or unsubstituted phenyl, 0 R ⁴ = H, alkyl, Δ (b)

with R = H, alkyl; 1 2 3

- R, R, R are identical or different from each other and represent an aliphatic group having from 1 to 8 carbon atoms, the methyl, ethyl, propyl, pentyl, hexyl, allyl, acetyl, propionyl groups being preferred and the methyl group being especially preferred.

- x = 1 or 2 excluding the following complexes (I):

1) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= CH3

2) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (Ia), R ⁴ = H, and Z = Z '= (n) - C3H7

3) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= CF3

4) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= - O - CH3

5) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= - O - C2H5

6) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = CH3, Z '= - O - CH3

7) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, etZ = CH3, Z '= - O - C2H5

8) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, etZ≈CH3, Z '= CF3

9) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = CH3, Z '= phenyl

10) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= C2H5

11) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= W0-C3H7

12) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= n-C4H9

13) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= W0-C4H9

14) + x = 2, R ¹ = R ² = R ³ = CH3, Cy = (la), R ⁴ = H, and Z = Z '= n-CsHπ

2 - Hydrosilylation catalyst between, on the one hand, 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 other on the other hand, compounds B having at least one reactive unsaturated aliphatic group and / or at least one reactive function, said catalyst being (thermo) photoactivatable and comprising at least one platinum complex, characterized in that the platinum complex is chosen from the complexes (I) without excluding the complexes (1) to (14) given in claim 1.

3 - Hydrosilylation process between, on the one hand, 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 other part, of compounds B having, per molecule, at least one reactive unsaturated aliphatic group and / or at least one reactive function, in which at least one complex of platinum is used as catalyst, characterized in that it consists essentially reacting compounds A and B in the presence of the catalyst according to claim 2 and by photoactivation.

4 - Process according to claim 3, characterized in that the compounds A are chosen from polyorganohydrogensiloxanes comprising:

* reasons for the following formula:

H _a W _b SiO ₄ . ( _a + b) (D 2

in which: the symbols W are similar or different and represent monovalent hydrocarbon groups, free from any unfavorable action on the activity of the catalyst and preferably chosen from (cyclo) alkyl groups having from 1 to 18 carbon atoms included and, advantageously, among the methyl, ethyl, propyl, octyl and 3,3,3-trifluoropropyl groups as well as among the C 6 -C 12 aryl or aralkyl groups and, advantageously, among the xylyl and totyl and phenyl radicals, all these groups possibly being halogenated (fluorine eg) and / or hydroxylated and / or alkoxylated. a is 1 or 2, b is 0, 1 or 2, the sum (a + b) has a value between l and 3, * and, possibly, other units of average formula:

5 - Method according to claim 3, characterized in that the compounds B are selected from polyorganosiloxanes comprising similar or different units of formula:

W _d XeYfSiθ4 - (d + e + f) (3) 2 in which: Δ the symbols W correspond to the same definition as that given above for W, Δ the symbols X are similar or different and represent an atom of hydrogen or a reactive polar function, preferably epoxyfunctional, linked to silicon by a divalent radical eg in C1-C20 optionally comprising at least one heteroatom, the radicals X more particularly preferred being: 3-glycidoxypropyl, 4-ethanediyl, (1,2 -époxyclohexyl) ...,

Δ The symbols Y are similar or different and represent a linear or branched alkenyl radical in Ci -Ci 2, alkenyl residue having at least one ethylenic unsaturation at the chain end and / or in the chain and optionally at least one heteroatom; Δd, e and f are equal to 0, 1, 2 or 3 and d + e + f = 0, 1, 2 or 3; the rate of Siθ / 2 units being less than 30% by mole.

6 - Process according to claim 5, characterized in that the residues Y are chosen from the following list: vinyl, propenyl, 3-butenyl, 5-hexenyl, 9-decenyl, 10-undecenyl, 5.9-decadienyl, 6, 1,1-dodecadienyl. 7 - Process according to claim 5 or 6, characterized in that the compounds B consist of a mixture of the products of formula (3).

8 - Process according to any one of claims 1 to 7, characterized in that the reaction mixture comprises compounds A, and compounds B in an amount such that the molar ratio SiH / unsaturated group and / or reactive polar function is between 0.4 and 10, preferably between 1 and 4 and, more preferably still, on the order of 2.5 ± 0.5, the catalyst being present in an amount of 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 compounds A and B present. 9 - Process according to any one of claims 3 to 8, characterized in that at least one photosensitizer is used having a triplet energy greater than or equal to 31 Kcal / mole and selected from (poly) aromatic products (possibly metallic) and heterocyclics, preferably in the list of following products: toluene, pyridine, ferrocene, benzene, thioxanthone, anthracene, benzophenone, this selection being made so that the lifetimes in triplet state of the complexes platinics and photosensitizer (s) are preferably of the same order.

10 - Process according to any one of claims 3 to 9, characterized in that at least one surfactant is added to the reaction medium, said agent preferably being a quaternary ammonium salt, tetraoctylammonium bromide being particularly preferred .

11 - Process according to claim 10, characterized in that the surfactant is present in the reaction medium at a rate 2 to 15 times, preferably from 5 to 10 times the molar amount of platinum-metal.

12 - Process according to any one of claims 3 to 11, characterized in that oxygen is introduced into the reaction medium before photoactivation.

13 - Process according to any one of claims 4 to 12, characterized in that the photoactivation takes place in the field of ultraviolet. 14 - Method according to any one of claims 4 to 13, characterized in that the photoactivation is coupled to a thermoactivation, advantageously using infrared radiation and preferably occurring after said photoactivation.

15 - Crosslinkable composition characterized in that it comprises:

- compounds A according to any one of claims 2 to 4,

- compounds B according to any one of claims 2, 3 and 5 to 8,

- A catalyst according to claim 2.

16 - Composition according to claim 15, characterized in that it comprises compounds A and B in an amount such that the molar ratio SiH / unsaturated group and / or reactive polar function is between 0.4 and 10, preferably between 1 and 4 and, more preferably still, of the order of 2.5 ± 0.5, the catalyst being present in an amount of 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 compounds A and B present. 17 - Composition according to claim 15 or claim 16, characterized in that it also comprises at least one photosensitizer having a triplet energy greater than or equal to 31 Kcal / mole and selected from (poly) aromatic products (optionally metallic) and heterocyclics, preferably from the following list of products: toluene, pyridine, ferrocene, this selection being made so that the triplet lifetimes of the platinum complexes and of the photosensitizer (s) are, preferably of the same order.

18 - Composition according to any one of claims 15 to 17, characterized in that it has at least one surfactant in the reaction medium, said agent preferably being a quaternary ammonium salt, tetraoctylammonium bromide being particularly preferred.

19 - Composition according to claim 18, characterized in that the surfactant is present in the reaction medium in a proportion 2 to 15 times, preferably from 5 to 10 times the molar amount of platinum-metal.