WO2003050174A1

WO2003050174A1 - Catalytic pgm mixture for hydrosilylation

Info

Publication number: WO2003050174A1
Application number: PCT/EP2001/015413
Authority: WO
Inventors: Oliver Brummer; Eric D. Carlson; Thomas Crevier; Yves Giraud; Anne-Marie La Pointe; Sébastien STERIN
Original assignee: Rhodia Chimie; Symyx Technologies, Inc
Priority date: 2001-12-11
Filing date: 2001-12-11
Publication date: 2003-06-19
Also published as: EP1453901A1; AU2002226401A1

Abstract

This invention relates to a one part mixture based on a PGM catalyst, a PGM inhibitor thereof and a ligand, convenient for the catalysis of hydrosilylation reactions and to polyaddition-curable polyorganosiloxane compositions including such a mixture

Description

Catalytic PGM mixture for hydrosilylation.

The present invention relates to the simultaneous use of a Platinum Group Metal (PGM) catalyst, a PGM inhibitor and a ligand, for the catalysis of hydrosilylation reactions and for the preparation of polyaddition-curable polyorganosiloxane compositions including such a mixture.

More specifically, the present invention relates to Platinium Group Metal (PGM) catalysed polyaddition-curable polyorganosiloxane compositions having an extended shelf and work life. More particularly, the present invention is directed to the employment of a new, catalytic composition in a heat curable polyorganosiloxane composition.

Polyaddition curable polyorganosiloxane compositions are well known in the art. A typical addition curable polyorganosiloxane composition involves an addition reaction in the presence of an effective amount of a PGM catalyst, such as platinum or rhodium catalyst, between a polyorganovinylsiloxane and a polyorganohydrogenosiloxane, such as a "silicon hydride siloxane". Usually, the PGM catalyst is employed as a mixture with the vinylpolysiloxane prior to contact with the polyorganohydrogenosiloxane material. Upon mixing the various ingredients, crosslinking or cure, often occurs within seconds at ambient temperatures. Various procedures have been developed in the art to achieve effective results with one part mixtures. While two part mixtures have the advantage of an indefinite shelf-life over a wide temperature range, in order to achieve the desired advantages in the one part mixture, the PGM catalyst must be inactive, or "masked" at ambient temperature. However, the PGM catalyst can be reactivated at the command of the end user at an appropriate higher temperature.

Accordingly, the PGM catalyst is generally used in combination with separately added inhibitors. Such inhibitors impart long term storage stability while allowing the silicone including them in combination with the platinum catalyst, to cure at an enhanced rate. For example, maleates, fumarates and acetylenic alcohols are presently recognized as choice one part PGM catalyst inhibitors. However, in many instances, a large ratio of moles of inhibitor to moles of platinum, such as 35:1 , is frequently required to inhibit cure at ambient conditions. The high inhibitor levels can result in curing temperatures that are not optimal.

Accordingly, the silicone industry is constantly trying to improve the performance of the catalytic systems used for the preparation of polyaddition- curable polyorganosiloxane compositions.

The present invention is based on the discovery that certain organic compounds, referred to hereafter as "ligand compounds" have been found to be highly effective to optimize the performance of such PGM catalytic systems.

The ligand / PGM / inhibitors exhibit good curing behavior (as measured by DSC). Most significantly, lower levels of inhibitor ( e.g., less than 10 moles of inhibitor for 1 mole of PGM) are needed. This data is significant when compared to inhibitors, such as dimethyl maleate of the prior art. Accordingly, a major object of the present invention is the provision of a mixture including at least a PGM catalyst, an effective PGM inhibitor and a ligand compound of formula I :

wherein : - Qi, Q₂, Q₃, Q₄, Q5, R4, R5. Ra and R₇ are independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heteroalkyl, substituted heteroalkyl, heterocycloalkyl, substituted heterocycloalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxyl, aryloxyl, silyl, boryl, phosphino, amino, thio, and combination thereof ; optionally, two or more Qi, Q₂, Q₃, Q and Q₅ and / or R₄, R₅, R₆ and R groups may be joined to form a fused ring system with the present aromatic ring ;

- R₂ is selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl, and substituted aryl ; and - R₃ is selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl, and substituted aryl and a phosphino characterized by the formula -PZιZ₂, where each of Zi and Z₂ is independently selected from the group consisting of substituted or unsubstituted alkyl, cycloalkyl, heterocycloalkyl, heterocycloaryl, substituted aryl, heteroaryl, alkoxy, aryloxy ; and

- Y is selected from the group of NR₈, S and O with R₈ being selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl, substituted aryl, and combination thereof. In the account which follows of the present invention, the term

"aromatic" means the conventional notion of aromaticity as defined in the literature, in particular by Jerry March, Advanced Organic Chemistry, 4^th edition, John Wiley and Sons, 1992, pp; 40 et seq.

As an illustration of the radicals from which Qi, to Q₅ and R₂ to Rs may be chosen and which may be used accordingly to the instant invention, mention may be made in particular of :

- linear or branched alkyl radical containing from 1 to 12 carbon atoms, the hydrocarbon-based chain possibly being interrupted with a functional group [for example - C(O) -] and/or bearing a substituent such as, for example, an aromatic or non-aromatic cyclic substituent. It may be in particular a linear or branched alkyl radical containing from 1 to 6 carbon atoms, preferably from 1 to 4 carbon atoms, such as methyl, propyl, isopropyl, butyl, isobutyl, sec-butyl or tert- butyl, or a linear or branched alkenyl radical containing from 2 to 6 carbon atoms, preferably from 2 to 4 carbon atoms, such as vinyl or allyl, or a Ci to C₁₂ arylalkyl radical such as benzyl,

- carbocyclic radical which is saturated or which comprises 1 or 2 unsaturations in the ring, generally containing from 3 to 8 carbon atoms and preferably 6 carbon atoms in the ring, the said ring possibly being substituted. It may be in particular a cycloalkyl group containing from 3 to 8 carbon atoms, such as a cyclohexyl group, and

- aromatic carbocyclic radical, preferably a monocyclic radical, generally containing at least 6 carbon atoms in the ring, the said ring possibly being substituted. It may in particular be phenyl. With regards to the substituents present on both cycles of the compound of formula I, they include alkyl, silyl, alkoxy, carboxyl radicals and halogen atoms. They may also be substituted. For example, they can be fluorinated derivatives, advantageously polyfluoroalkyl derivatives.

Accordingly to a preferred form of the invention, the phenyl cycle of formula I is disubstituted in meta with two groups of CF₃ or trisubstituted in ortho and para with three alkyl and preferably methyl groups.

Among the ligand compounds which can be used in accordance with the practice of the invention, prefered ligands include those shown by formula II:

wherein Qi to Q₅, and R₂ to R₇ are as defined in formula I.

In some embodiments Qi _Q₅ are independently selected from the group consisting of hydrogen, alkyl and substitued alkyl.

Preferably, the ligand compounds are the compounds of formula (I) and

(II) wherein

- each of Qi, Q₃ and Q5 is selected from the group consisting of alkyl and substituted alkyl, and each of Q₂ and Q₄ is substitued alkyl, more specifically hydrogen; - or wherein each of Qi, Q₃ and Q₅ is hydrogen and Q₂ and Q₄ are perfluoroalkyl and even more preferably a CF₃ radical.

As a compound of formula (I) or (II), specific examples include:

The pyridyl amine ligand (I) and (II) are prepared according to the technique known to those of skil in the art, and for example to the modus operandi of US patent Application n°09/ / , filed November 6, 2001 (Attorney Docket N°20006096DIV6, having Express Mail N° EL 910745618 US) For instance, the preparation comprises two steps. Firstly the reaction between 2- pyridinecarboxaldehyde and the corresponding aniline derivative gives imine compounds which are secondly reduced using an inorganic hydride such as NaBH or Na(OAc)₃BH. Compounds (I) and (II) are obtained after classical purification.

Various platinium Group Metal (PGM) catalysts can be used according to the present invention and include complexes of platinum, rhodium, ruthenium, and palladium. Preferably, platinum halide complexes and more preferably vinylsiloxane-platinium (0) complexes shown in Karstedt, US patent 3,715,334 which is incorporated herein by reference, are used.

Regarding the inhibitor compounds convenient for the instant invention, they can be divided in two families.

The first family includes compounds known as being able to inhibit the PGM activity by strongly coordinating it. Further they are not decomposed by heating or consumed by this reaction. Representatives of this family are phosphine and phosphite (US 3,188,300).

The second family includes compounds able to inhibit the hydrosilylation reaction but which are supposed to be slowly and selectively consumed during the inhibitio period. Representatives thereof are azodicarboxylate derivatives (US 5,640,939, US 4,670,531 and US 5,122,585), maleate derivatives (US 5,506,289), cyclic maleimide (US 4,530,989), acetylene dicarboxylate derivatives (US 4,504,645), unsaturated halogenated compounds (US 3,383,356 and EP 985 711), and α-acetylenic ketons (FR 2 554 118) and mixtures thereof. The preferred inhibitors include maleate, cyclic maleimide and acetylene dicarboxylate derivatives.

The ratio of the ligand compound to the PGM catalyst ranges from 1 to 100, preferably 1 to 5. The ratio of the PGM inhibitor to the PGM catalyst ranges from 1 to 100, preferably 1 to 10.

Another object of the instant invention relates to the use of an effective amount of the claimed mixture as a latent PGM catalyst for hydrosilylation reactions.

As specified hereabove, polyaddition curable polyorganosiloxane compositions are well known in the art. A typical addition curable elastomeric polyorganosiloxane composition involves an addition reaction in the presence of an effective amount of a PGM catalyst, such as platinum or rhodium catalyst, between a polyorganosiloxane (A) containing at least two unsaturated groups and a polyorganohydrogenosiloxane (B). The polyorganosiloxane (A) can be an polyorganosiloxane having alkenyl radicals or alkynyl groups, for example vinyl radicals attached to silicon by carbon-silicon bonds. In this case, the hydrosilylation reactions concerned by the present invention can be represented as follows :

— S i— H +"bC = C b^{^} * S i-C — C —

The PGM catalyst, PGM inhibitor and the ligand compound of formula I can be used under the form of a preformed mixture or introduced separately in the reactional mixture.

In the specific case where the inhibitor is either maleate or maleimide, the PGM catalyst , ligand and PGM inhibitor may be combined in any desired order prior to addition or upon addition to the silicone hydride material

Yet another object of the invention is to provide a polyaddition-silicone composition curable by hydrosilylation, comprising:

- at least one polyorganosiloxane (A) containing at least two unsaturated groups bonded to silicon atoms;

- at least one polyorganohydrogenosiloxane (B) containing at least two hydrogen atoms bonded to silicon atoms and;

- a catalytically effective amount (C) of the claimed catalytic mixture. According to a preferred embodiment, the weight of claimed mixture (C) calculated as the weight of platinum metal, typically ranges from 0,1 to 600 ppm, and preferably from 1 to 100 ppm, based on the total weight of the polyorganosiloxanes (A) and (B).

The unsaturated groups of the polyorganosiloxane A are for example C₂-Cs alkenyl groups, e.g: vinyl, allyl, 1-butenyl, 1-hexenyl, etc. The unsaturated groups may be bonded to the silicon atoms within the chain and/or right at the end. The organic substituents, different from unsaturated groups and hydrogen atom, are for example alkyl, cycloalkyl, aryl, aryalkyl and/or alkylaryl radicals and can be substitued.

The hydrogen and unsaturated radicals are present on siloxyl moieties M = [R₃SiO-] , D = [-(R)₂SiO-] and/or T = [-(R)SiO-], with R being partially as defined for Z hereafter.

Generally, the polyorganosiloxanes (A) and (B) used in the reaction have a molecular mass weight comprised between 10² and 10⁶ (g/mol).

The amounts of the polyorganosiloxanes (A) and (B) are typically selected such that the molar ratio of the hydrogen atoms bonded to silicon in (B) to the unsaturated radicals bonded to silicon in (A) generally ranges from 0,6 to 5, preferably from 1 to 3.

In other words, the polyorganosiloxanes may comprise from 0,01 % to 10% (preferably 0,1 % to 2%) of unsaturated radicals by weight for the polyorganosiloxane (A) and from 0,001 % to 5% (more preferably from 0,005% to 2%) of hydrogen by weight for the polyorganosiloxane (B).

The vinyl groups in (A) and the hydrogen atoms in (B) are typically bonded to different silicon atoms.

The various bases, i. e. : the mixture based on (A), (B), (C) and optionally filler(s) and processing aids, for the subject polyaddition silicone compositions, are well known to those of skill in the art. Most of them are available commercially. According to a preferred embodiment, the polyorganosiloxane (A) is an polyorganosiloxane containing

• siloxy units of the formula (1) :

Ta Zb Si O_[4-_(a+b)] /2 (1) in which :

- the radicals T, equal or different, are unsaturated groups and preferably vinyl type groups,

- the radicals Z, equal or different, are monovalent hydrocarbon groups which do not adversely affect the activity of the catalyst; Z being preferably selected from (i) alkyl groups containing from 1 to 8 carbon atoms, optionally substituted by at least an atom of halogen, (ii) cycloalkyl groups containing from 3 to 8 carbon atoms, optionally substituted by at least an atom of halogen, (ii) aryl groups from 6 to 32 carbon atoms such as xylyl and tolyl and phenyl, optionally substituted by at least an atom of halogen, (iv) alkylaryl groups with alkyl group(s) from 1 to 8 carbon atoms and aryl groups from 6 to 30 carbon atoms, optionally substituted by at least an atom of halogen,

- and a is 1 or 2, b is 0, 1 or 2, with a + b ranges from 1 to 3. • with the proviso that the polyorganosiloxane (A) comprises at least two radicals T.

• and, if desired, other units are units of the average formula: (2)

Zc Si O₍₄- c) /2 (2)

in which Z is as defined above and c has a value from 0 to 3.

The polyorganosiloxane (A) may have a linear, branched, ring or lattice structure.

Specific examples of siloxy units of formula (1) are the vinyldimethylsiloxy unit, the vinylphenylmethylsiloxy unit, the vinylsiloxy unit and the vinylmethylsiloxy unit. Specific examples of siloxy units of formula (2) are the Si0 _/2, dimethylsiloxy, methylphenylsiloxy, diphenylsiloxy, methylsiloxy and phenylsiloxy units.

The polyorganosiloxane (A) may be constituted solely by units of formula (1 ) or may additionally contain units of formula (2).

Regarding the polyorganohydrogenosiloxane (B), this latter is preferably an polyorganohydrogenosiloxane containing :

• siloxy units of the formula (3): Hd We Si O_[4._{(d+e)]/ 2} (3) in which : - W, equal or different, are monovalent hydrocarbon groups which do not adversely affect the activity of the catalyst and which has the same definition as Z, - and d is 1 or 2, e is 0, 1 or 2, with d+e having a value from 1 to 3,

• with the proviso that the polyorganohydrogenosiloxane (B) comprises at least two hydrogen atoms.

• and, if desired, all the other units are units of the average formula (4):

Wg Si O₍4._g) /2 (4)

in which W is as defined above, and g has a value from 0 to 3. All of the limiting values of a, b, c, d, e and g are included.

The polyorganosiloxane (B) may be constituted solely by units of formula (3) or may additionally contain units of formula (4).

The polyorganosiloxane (B) may have a linear, branched, ring or lattice structure. The degree of polymerization is 2 or more and is generally less than 5,000. Examples of units of formula (3) are: H(CH₃)₂ SiOι ₂, HCH₃ Si0_{2 2}, H(C₆

The examples of units of formula (4) are the same as those given above in the case of the units of formula (2).

The most preferred polyorganosiloxane (A) for the polyaddition silicone compositions according to the present invention are those comprising :

• siloxyl moieties having the general formula (5) :

• and / or siloxyl moieties of formula (6) :

(T)_y (Z')_zSiO₍₄._y._z)/2 (6) in which :

- the radicals Z equal or different, represent hydrocarbonated preferably selected in the group consisting of :

* alkyl radical, halogenoalkyl having from 1 to 5 carbon atoms and having from 1 to 6 chloride and/or fluorine atoms, * cycloalkyl and halogenocycloalkyl radicals having from 3 to 8 carbon atoms and containing from 1 to 4 chloride and/or fluorine atoms,

* aryl, alkylaryl and halogenoaryl radicals having from 6 to 8 carbon atoms and containing from 1 to 4 chloride and/or fluorine atoms, - the radicals T, equal or different, are unsaturated radicals C₂-C₆.

- x is 0,1 , 2 or 3 ; - y is 1 , 2 or 3 ;

- z is 0,1 , 2 or 3 ;

- and y+z ranges from 1 to 3 ; • with the proviso that the polyorganosiloxane (A) comprises at least two radicals T'.

The most preferred polyorganohydrogenosiloxane (B) for the polyaddition silicone compositions according to the present invention are those comprising :

• siloxyl moieties having the general formula :

• and/or siloxyl moieties of formula : (H)_y (Z')_zSi0₄._y._z/2 (6') in which :

- the radicals Z¹, equal or different, represent a hydrocarbonated preferably selected in the group consisting of : * alkyl radical, halogenoalkyl having from 1 to 5 carbon atoms and having from 1 to 6 chloride and/or fluorine atoms, * cycloalkyl and halogenocycloalkyl radicals having from 3 to 8 carbon atoms and containing from 1 to 4 chloride and/or fluorine atoms, *aryl, alkylaryl and halogenoaryl radicals having from 6 to 8 carbon atoms and containing from 1 to 4 chloride and/or fluorine atoms, - x is 0,1 , 2 or 3 ; - y is 1 , 2 or 3 ;

- z is 0,1 , 2 or 3 ; - and y+z ranges from 1 to 3 ;

More preferably, Z is selected in the group consisting of methyl ; ethyl propyl ; isopropyl ; butyl ; isobutyl ; n-pentyl ; t-butyl ; chloromethyl dichloromethyl ; α-chloroethyl ; α,β-dichloroethyl ; fluoromethyl ; difluoromethyl α,β-difluoromethyl ; trifluoro-3,3,3 propyl ; trifluoro cyclopropyl ; trifluoro-4,4,4 butyl ; hexafluoro-3,3,4,4,5,5 pentyl ; phenyl ; p-chlorophenyl ; m-chlorophenyl ; dichloro-3,5 phenyl ; trichlorophenyl ; tetrachlorophenyl ; o-, p- or m-tolyl ; α,α,α- trifluorotolyl ; xylyl like dimetyl-2,3 phenyl, dimethyl-3,4 phenyl and more preferably is methyl or phenyl, these radicals being optionally halogenated.

Specific examples of polyorganosiloxanes (A) are dimethylpolysiloxanes with dimethylvinylsiloxy end groups, the methylvinyldimethylpolysiloxane copolymers with trimethylsiloxy end groups, methylvinyldimethylpolysiloxane copolymers with dimethylvinylsiloxy end groups and cyclic methylvinyl- polysiloxanes. Specific examples of polyorganohydrogenosiloxanes (B) are dimethylpolysiloxanes with hydrodimethylsilyl end groups, dimethylhydro- methylpolysiloxane copolymers with trimethylsiloxy end groups, dimethylhydromethylpolysiloxane copolymers with hydrodimethylsiloxy end groups, hydromethylpolysiloxanes with trimethylsiloxy end groups, cyclic hydromethylpolysiloxanes and copolymers methylhydrogenomethyloctylsiloxane copolymers.

For the polyorganosiloxane (A), it includes in particular with regard to dynamical viscosity at 25°C the following polyorganosiloxanes :

A1 - polyorganosiloxane vulcanisable by heating (EVC) by polyaddition, having a viscosity at least equal to 10⁴ mPa.s, preferably comprised between 10⁶ and 10⁷ mPa.s ; and

A2 - polyorganosiloxane vulcanisable by heating, by polyaddition of liquid elastomer silicones (LSR), having a viscosity preferably comprised between 10² and 10⁴ mPa.s.

According to a preferred embodiment of the invention, the claimed polyorganosiloxane compositions are vulcanisable by heating (EVC) by polyaddition and include polyorganosiloxane A1 and a polyorganohydrogenosiloxane B having a viscosity of 10² to 10⁷ mPa.s at 25°C.

The viscosity is evaluated with a Brookfield viscometer according to AFNOR NFT 76 106 of May 1982. All viscosities referred in the instant specification correspond to a dynamical viscosity at 25°C said "Newtonian".

According to a preferred embodiment, the catalytic composition includes (i) an effective amount of a platinium complex, preferably a Karstedt complex, (ii) an effective PGM inhibitor like for example a dialkylacetylenedicarboxylate such as dimethylacethylenedicarboxylate and (Hi) as a compound of formula I, the following compound 2-picolyl-2,4,6-trimethylphenylamine, or 2-picolyl-3,5- bis(trifluoromethyl)phenylamine :

The compositions according to the invention may additionally comprise reinforcing or semireinforcing or extending fillers (D), which are preferably siliceous fillers.

The reinforcing fillers are selected from the pyrogenic silicas and precipitated silicas. They have a specific surface area, measured according to the BET method, of at least 50 m2 /g, preferably greater than 70 m2 /g, a mean primary particle size of less than 0.1 micrometer and an apparent density of less than 200 g/liter. These silicas may be incorporated as such or preferably after they have been treated with organosilicon compounds usually employed for this purpose. In the course of this treatment, the silicas may increase in their initial weight up to a proportion of 20%.

The semireinforcing or extending fillers have a particle diameter greater than 0.1 micrometer and are preferably selected from among ground quartz, calcined clays and diatomaceous earths.

From 5 to 100 parts, preferably from 5 to 50 parts of filler (D) may generally be employed per 100 parts of the total amount of the polyorganosiloxanes (A)+(B). The claimed polyorganosiloxane composition can include furthermore other compounds such as hydroxylated polyorganosiloxane oil(s), adherence promotor(s), adherence modulator(s) and/or pigment(s).

The compositions according to the invention may be kneaded as such and may be extruded or molded in the form of unit modules (elements); the composition may, for example, be molded into the shape of a cylinder with a diameter of from 0.5 to 9 cm. After curing, the silicone composition cylinders which are obtained may be cut to the desired length.

The instant invention concerns also said silicone composition in crosslinked elastomeric state.

The present invention is also directed to shaped article comprising the claimed silicone composition curable or cured by hydrosilylation in crosslinked elastomeric state or not.

In order to further illustrate the present invention and the advantages thereof, the following specific examples are given, it being understood that same are intended only as illustrative and in nowise limitative.

Examples.

In each following examples, ligand L1 is

The platinum catalyst used is shown by Karstedt US patent 3,715,334.

A. Preparation of the ligand 1-1 :.

2 steps synthesis of the pyridylamine ligand L1.

1 - A solution of 2-formylpyridine and 2,4,6-trimethylaniline in anhydrous THF containing 3 A sieves and a catalytic amount of TsOH was heated to reflux under N₂ for 12 h. After filtration and removal of the volatiles in vacuo, the crude material was passed through a plug of neutral alumina with 1 :1 hexane/CH₂CI₂ eluent. Removal of the volatiles provided pyridine-2- (mesityl)imine as yellow crystals.

2 - The second step in the reaction sequence is a reduction reaction using sodiumtriacetoxyborohydride (Na(OAc)₃BH) in THF for 1-3 days followed by an aq. NH₄CI quench. The organic layer was separated, washed with brine and H₂0, then dried over Na₂S0 . Following chromatography (silica gel, 3% THF/hexane), the product was isolated as a colorless solid.

B. Preparation of silicone composition according to the invention.

Each reaction mixture is prepared as followed :

An amount of ligand L1 to provide the determined molar ratio L1/Pt is dissolved in few μl_ of toluene. There was then added a predetermined amount of platinum catalyst to provide 67 ppm of Pt (calculated from the total weight of vinylsiloxane fluid and hydride siloxane fluid).

After that, 10 parts of a vinylsiloxane silicon fluid having 0,61 % by weight vinyl are added to the solution. Then, an amount of dimethylacetylenedicarboxylate (DMAD) to provide the determined molar ratio

DMAD / Pt is added. After short stirring, 2,7 parts of a silicon hydride siloxane having 0,17% by weight hydrogen are added.

Each reaction mixture is placed in a DSC pan. DSC is run at 10°C/min from 25°C to 250°C. DSC analyses of the above formulations are shown in tables 1 and 2. The results in the tables show that the catalytic system of the invention show a substancially superior inhibiting performance and is associated with a good reactivity.

Table !

Table 2.

Claims

CLAIMS.

1. A mixture including at least a PGM catalyst, an effective PGM inhibitor and a ligand compound of formula I :

wherein :

- Qi, Q₂, Q₃, Q₄, Q₅, R , R5, R_Θ and R₇ are independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heteroalkyl, substituted heteroalkyl, heterocycloalkyl, substituted heterocycloalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxyl, aryloxyl, silyl, boryl, phosphino, amino, thio and combination thereof ; optionally, two or more Qi, Q₂, Q₃, Q₄, Q₅ and/or R , R₅, R₆, R groups may be joined to form a fused ring system with the present aromatic ring ; - R is selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl, and substituted aryl ; and

- R₃ is selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl and substituted aryl, and is a phosphino characterized by the formula -PZιZ₂, where each of Zi and Z₂ is independently selected from the group consisting of substituted or unsubstituted alkyl, cycloalkyl, heterocycloalkyl, heterocycloaryl, substituted aryl, heteroaryl, alkoxy, aryloxy ; and

- Y is selected from the group of NR₈, S and O with Rs being selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl, substituted aryl, and combination thereof.

2. A mixture according to claim 1 , wherein the ligand compound is of formula II:

wherein Q to Q₅, and R₂ to R₇ are as defined in claim 1.

3. A mixture according to claims 1 to 2, wherein

- each of Qi, Q₃ and Q5 is selected from the group consisting of alkyl and substituted alkyl and each of Q₂ and Q₄ is substitued alkyl, more preferably hydrogen,

- or wherein each of Qi, Q₃ and Q₅ is hydrogen and Q₂ and Q₄ are perfluoroalkyl and more preferably a CF₃ radical.

4. A mixture according to claims 1 to 3 wherein the ligand compound is :

5. A mixture according to claims 1 to 4 wherein the platinum Group

Metal (PGM) catalysts is selected among complexes of platinum, rhodium, ruthenium and palladium.

6. A mixture according to claim 5 wherein it is a platinum halide complexe or a Karstedt complexe.

7. A mixture according to claims 1 to 6 wherein the effective PGM inhibitor is selected from the group consisting of phosphine, phosphite, azodicarboxylate derivatives, maleate derivatives, cyclic maleimide, acetylene dicarboxylate derivatives, halogenated unsaturated compounds, α-acetylenic ketons and mixtures thereof.

8. A mixture according to claim 1 to 7 wherein the PGM inhibitor is a maleate, cyclic maleimide and/or an acetylene dicarboxylate derivative.

9. One part mixture according to claims 1 to 8 wherein the ratio of the ligand compound to the PGM catalyst ranges from 1 to 100, preferably 1 to 5.

10. A mixture according to claims 1 to 9 wherein the ratio of the PGM inhibitor to the PGM catalyst ranges from 1 to 100, preferably 1 to 10.

11. Use of an effective amount of the mixture according to claim 1 to 10 as a preformed latent PGM catalyst for hydrosilylation reactions.

12. Use of a PGM catalyst, PGM inhibitor and a compound ligand of formula I as defined in claim 1 to 10 for catalyzing hydrosilylation reactions.

13. Polyaddition-silicone composition curable by hydrosilylation, comprising:

- at least one polyorganosiloxane (A) containing at least two unsaturated groups bonded to silicon atom(s);

- at least one polyorganohydrogenosiloxane (B) containing at least two hydrogen atoms bonded to silicon atom(s) and ; - and a catalytically effective amount (C) of a mixture according to claim

1 to 10.

14. Polyaddition-silicone composition curable by hydrosilylation wherein the polyorganosiloxane (A) is an polyorganosiloxane comprising: • siloxy units of the formula (1) :

Ta Zb Si O _[4.₍a4-b)] /2 (1) in which : - the radicals T, equal or different, are unsaturated groups,

- the radicals Z, equal or different, are monovalent hydrocarbon groups which do not adversely affect the activity of the catalyst; Z being preferably selected from (i) alkyl groups containing from 1 to 8 carbon atoms, optionally substituted by at least an atom of halogen, (ii) cycloalkyl groups containing from 3 to 8 carbon atoms, optionally substituted by at least an atom of halogen, (iii) aryl groups from 6 to 32 carbon atoms such as xylyl and tolyl and phenyl, optionally substituted by at least an atom of halogen, (iv) alkylaryl groups with alkyl group(s) from 1 to 8 carbon atoms and aryl groups from 6 to 30 carbon atoms, optionally substituted by at least an atom of halogen,

- and a is 1 or 2, b is 0, 1 or 2, with a + b ranges from 1 to 3.

- with the proviso that the polyorganosiloxane A comprises at least two radicals T. • and, if desired, other units of the average formula: (2)

Zc Si O ₍₄- c) /2 (2)

in which Z is as defined above and c has a value from 0 to 3.

15. Polyaddition-silicone composition curable by hydrosilation according 14 wherein the polyorganosiloxane (A) comprises: • siloxyl moieties having the general formula (5) :

• and / or siloxyl moieties of formula (6) :

(T')_y (Z')_zSiO₍₄._y._z)/2 (6) in which :

- the radicals Z', equal or different, represent hydrocarbonated groups preferably selected in the group consisting of : * alkyl radical, halogenoalkyl having from 1 to 5 carbon atoms and having from 1 to 6 chloride and/or fluorine atoms, * cycloalkyl and halogenocycloalkyl radicals having from 3 to 8 carbon atoms and containing from 1 to 4 chloride and/or fluorine atoms,

* aryl, alkylaryl and halogenoaryl radicals having from 6 to 8 carbon atoms and containing from 1 to 4 chloride and/or fluorine atoms,

- the radicals T, equal or different, are unsaturated radicals C₂-C₆. - x is 0,1 , 2 or 3 ; - y is 1 , 2 or 3 ;

- z is 0,1 , 2 or 3 ;

- and y+z ranges from 1 to 3 ; • with the proviso that the polyorganosiloxane (A) comprises at least two radicals T.

16. Polyaddition-silicone composition curable by hydrosilylation according to claim 14 or 15 wherein the polyorganohydrogenosiloxane (B) is a polyorganohydrogenosiloxane containing :

• siloxy units of the formula (3):

Hd We Si O [4-(d+e)] / 2 (3) in which

- W, equal or different, are monovalent hydrocarbon groups which do not adversely affect the activity of the catalyst and which has the same definition as Z,

- and d is 1 or 2, e is 0, 1 or 2, with d+e having a value from 1 to 3,

• and, if desired, all the other units are units of the average formula (4): Wg Si 0(4-g) / 2 (4)

in which W is as defined above, and g has a value from 0 to 3. All of the limiting values of a, b, c, d, e and g are included,

• with the proviso that the polyorganohydrogenosiloxane (B) comprise at least two hydrogen atoms.

17. Polyaddition-silicone composition curable by hydrosilylation according to claim 16 wherein the polyorganohydrogenosiloxane (B) comprises :

• siloxyle moieties having the general formula :

• and/or siloxyle moieties of formula :

(H)_y (Z')_zSiO₍₄._y._z)/2 (6') in which :

- the radicals Z', equal or different, represent a hydrocarbonated and no hydrolysable radical, preferably selected in the group consisting of ^* alkyl radical, halogenoalkyl having from 1 to 5 carbon atoms and having from 1 to 6 chloride and/or fluorine atoms,

* cycloalkyl and halogenocycloalkyl radicals having from 3 to 8 carbon atoms and containing from 1 to 4 chloride and/or fluorine atoms,

- x is 0,1 , 2 or 3 ; - y is 1 , 2 or 3 ;

- z is 0,1 , 2 or 3 ;

- and y+z ranges from 1 to 3 ; • with the proviso that the polyorganohydrogenosiloxane (B) comprise at least two hydrogen atoms.

18. Polyaddition-silicone composition curable by hydrosilylation according to claim 13 to 17 wherein the polyorganosiloxane (A) is a polyorganosiloxane vulcanisable by heating (EVC) by polyaddition, having a viscosity at least equal to 10⁴ mPa.s., and the polyorganohydrogenosiloxane (B) has a viscosity of 10² to 10⁷ mPa.s at 25°C.

19. Polyaddition-silicone composition curable by hydrosilylation according to claim 13 to 18 wherein the mixture (C) calculated as the weight of platinum metal is employed from 1 to 600 parts, and preferably from 2 to 100 parts based on the total weight of polyorganosiloxanes (A)+(B).

20. Polyaddition-silicone composition curable by hydrosilylation according to claim 13 to 19 further comprising from 5 to 100 parts of reinforcing or semireinforcing siliceous filler material (D) per 100 parts of the polyorganosiloxanes (A)+(B).

21. A shaped article comprising the silicone composition according to claim 13 to 20.

22. Polyaddition-silicone composition curable by hydrosilylation according to claim 13 to 21 in crosslinked elastomeric state.

23. A shaped article comprising the crosslinked elastomeric silicone composition as defined by claim 22.