Anti-fouling polyaddition silicone varnish, application of said varnish to a support and support treated thus

ι

ANTI-SOILING POLYADDITION SILICONE VARNISH,

APPLICATION OF THIS VARNISH ON A SUBSTRATE

AND SUPPORT THUS TREATED

The general field of the invention is that of polymer coatings or varnishes capable of imparting to supports optionally at least in part made up of silicone, among others, resistance to soiling, easy implementation, slippery nature, etc.

More specifically, the invention relates to silicone compositions which are useful in particular for producing varnishes applicable to supports, the tendency of which is to be reduced, in particular, to soiling.

The media involved are diverse and may consist in particular of:

by flexible supports, in particular fibrous, woven or not, coated with at least one protective or mechanical reinforcing layer, based on a coating polymer, of the silicone elastomer type, for example; flexible supports of silicone elastomers reinforced with fibers, whether or not woven with solid silicone supports and / or coated with one or more layers of silicone, for example metal, plastic or ceramic parts (composite parts such as cables and electrical insulators eg);

or else by polymer or elastomeric supports, in particular plastic films, such as for example: thermal transfer ribbons which can be used in particular as an ink support in thermal transfer printers or protective packaging films.

The present invention also relates to the methods of applying the antifouling varnish to which it relates, on various supports.

Finally, the subject of the invention is the supports coated with such anti-fouling varnishes and, in particular:

o flexible supports such as textile fabrics possibly coated with a layer of silicone elastomer on which the anti-fouling varnish is applied, such fabrics being capable of being used for manufacture, eg:

* elements of textile architecture (tarpaulins, shelters, flexible doors, etc.) and flexible fire-resistant membranes * of certain upholstery fabrics * of specific clothing * of airbags * of glass braids * of conveyor belts * thermal transfer ribbons * compensators, for example constituted by plastic films (eg polyester) carrying ink and usable in thermal transfer printers;

* protective packaging films;

o and solid parts, for example made of silicone elastomers.

It is known practice to coat flexible (textile) or bulk supports using films or polymer coatings, for example silicones, preferably in the form of elastomers.

The silicone elastomer coatings on supports eg of a fibrous nature already provide, because of the intrinsic properties of silicones, numerous advantages to the composites thus formed, namely, inter alia, good flexibility and good mechanical strength.

Moreover, unlike traditional elastomers, silicones give them, among other things, increased thermal resistance and long life.

These characteristics are widely exploited in the uses of these coated fabrics for the manufacture of airbags.

Thus, patent FR-B-2,719,598 discloses cold vulcanizable silicone elastomer compositions (EVF) by polyaddition, for the production of nylon® textile fabrics intended for the manufacture of air bags. These compositions comprise a mixture formed from:

(I) 25 p / p Oil POS (M^viDM^vi): PolyDiMethylSiloxane -PDMS- α, ω (dimethylvinylsiloxy) with a viscosity of 100,000 mPa.s containing approximately 0.083 mol% of M groups^vi = (CH3) 2 (CH2 = CH) SiOi / 2, D^vi = (CH3) (CH2 = CH) SiO2 /₂ ;

(Γ) 21p / p PDMS M^viDM^vi (10,000 mPa.s), (SiVi = 0.083 mol%), (II) 5p / p Oil POS (M^HDD^HM^H): poly (dimethylsiloxy) (methylhydrogenosiloxy) α, ω dimethylhydrogenosiloxy, with a viscosity of 300 mPa.s and containing 0.17 mol% of H groups;

(III) Pt catalyst (IV) 5p / p an adhesion promoter (VTMO / GLYMO / Ti (OBu) 4;

(V) optionally a mineral filler, (VI) 0.03p / p EthynylCycloHexanol (VII) 38p / p vinylated POS resin = M^viDD^viM^viQ (SiVi = 0.6% by weight).

VTMO vinyltrimethoxysilane

GLYMO gamma-Glycydoxypropyltrimethoxysilane

Bu: butyl

Nevertheless, it is known that the coating layers of elastomeric silicone often have a somewhat catchy feel which is detrimental for airbags. This concern for surface slippage is also of interest to coatings for thermal transfer ribbons (eg made of polyester) or even protective packaging films (eg made of polyethylene or polypropylene.

Thermal transfer ribbons are suitable for use in thermal transfer printers. These thermal transfer ribbons are very thin (a few microns) and are coated, on one of their faces, with a layer of ink (waxes or resins) and on the other of their faces, with a coating of protection. In general, a very thin protective coating with a thickness of between 0.1 and 1 micrometer is used to protect the surface of the film and improve the impact of the print head without distorting the transfer of the ink to the applied medium. . In printers with printing speeds between 150 and 300mm / s, it is very important that the printhead (flat or wedge), when it hits the protective coating of the ribbon, can slide on the surface of the coating, at an elevated temperature between 100 and 200 ° C.

With regard to protective packaging films, provision is sometimes made to apply a silicone-based over-varnish to them, in order to give them non-stick properties. But this over-varnishing should have a slippage at least equivalent to that of the starting plastic film (printed or not).

In all the cases cited above by way of illustration, the composites suffer from a lack of slip, which can be associated with the mechanical and surface properties (too high coefficient of friction) of silicones.

In the case of textile applications, this drawback of lack of slip is manifested in practice by a low mobility of the coated fabrics on the preparation tables, which penalizes their productivity. More specifically in the case of airbags, it is the deployment of the bag when the airbag is triggered which can be braked in a very detrimental manner.

Various types of treatment can be envisaged to overcome this difficulty. However, the sliding surface / use properties compromise is such that varnishing seems to be one of the most suitable means for this purpose.

In the field of architectural textiles or upholstery textiles, manufacturers are also asking for fibrous support (woven or not) / elastomeric coating composites which not only have the essential characteristics mentioned above, but also performance. important additional items such as:

* resistance to soiling, * good appearance characteristics, in particular with regard to coloring and gloss, * ability to spread over a silicone layer, or even non-silicone (for example Polyvinyl Chloride, Polyurethane, PolyAmide) , * easy and economical to use on an industrial level, * and good cohesion of the composites.

These properties can be provided by a suitable surface coating (varnishing).

The general problem underlying the invention is therefore the development of a silicone varnish suitable for fulfilling this role perfectly, in particular as regards the anti-fouling properties.

PCT application WO-A-OO / 59992 (R99035) describes silicone compositions useful in particular for producing varnishes applicable on supports, the friction coefficient of which is sought to be reduced. One of these compositions comprises at least one polyorganosiloxane A (POS) which can be crosslinked by means of crosslinking functional groups (GFR) by the cationic and / or radical route and an initiator C chosen from onium borates, characterized in that that it also comprises POS D molecules substituted by secondary functional groups (GFS) carried by silicon atoms and selected from those comprising at least one alkoxy and / or epoxy and / or carboxy unit, and optionally a filler (eg silica).

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If (CH₃)₃

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These compositions can also comprise fillers and in particular silicic fillers which can be, for example:

combustion silicas treated with hexamethyldisilazane or with roctamethyl-cyclotetrasiloxane (specific surface up to approximately 300 m²/ g), fumed silicas, crushed synthetic or natural fibers (polymers), calcium carbonates, talc, clays, titanium dioxides ...

Such compositions are used as an anti-fouling varnish for RTV silicone coatings of air bag fabrics, for thermal transfer ribbons or for packaging films.

Such varnishes are not the most efficient in terms of anti-fouling properties and can still be improved in terms of slip coefficient. In addition, they require the use of particular silicones crosslinkable by the cationic route under UV activation, which leaves room for improvement in economic terms and in terms of simplification of the means used.

PCT application WO-A-WO 03/106564 describes an anti-friction silicone varnish for textiles coated with silicone elastomers. This economical, adherent varnish, providing the desired slippage, resistant to dirt, and gloss, is formed by a silicone composition which can be crosslinked by polyaddition comprising, on the one hand, parts of PDMS containing approx. 2.5% Vi as D groups^V1 parts of PDMS α, ω-diMeVi with a viscosity of 600 mPa.s parts of PDMS α, ω diMeVi with a viscosity of 100 Pa.s

0.052 parts of ethynylcyclohexanol parts of γ methacryloxypropyltrimethooxysilane parts of polymethylhydrogenosiloxane with a viscosity of 20 mPa.s

0.1 parts of platinum catalyst parts of a particulate component (D), namely Orgasol® 2002 ES3 (PA powder with an average diameter of 30 μm).

Patent application WO-A-2004067613 discloses another silicone varnish for anti-fouling coating of silicone composites. This varnish comprises a composition of functional silanes which crosslinks under the action of atmospheric humidity and, in a manner, accelerated when hot. This composition is, for example the following:

~ Alkenylsilane -Al-: Vinyltrimethoxysilane (VTMO), ~ Alkenylsilane -A.2-: Dynasilan® 6490 is a condensate of vinyltrimethoxysilane (VTMO) marketed by Degussa, ~ Component -Bl- of the catalytic system: DADBE: dibutyl diacetate, ~ Component -B.2- of the catalytic system: TBOT: butyl titanate, ~ Ultrafine filler -C-: R812 is a treated fumed silica marketed by Degussa.

Patent application WO-A-2004067620 discloses yet another anti-fouling silicone varnish for textiles coated with silicone elastomers. This economical, adherent, slightly slippery and shiny varnish comprises a crosslinkable silicone composition based on per 100 parts by weight:

-1- at least 80 parts by weight of:

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-2- from 0.1 to 10 parts by weight of:

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-3- from 0 to 10 parts by weight of at least one polydimethylsiloxane (PDMS) acrylate or epoxy;

-4- from 0 to 10 parts by weight of at least one silylated compound as defined above and carrying, per molecule, at least one epoxy group;

-5- from 0 to 10 parts by weight of at least one PDMS acrylate / epoxy;

-6- from 0 to 10 parts by weight of at least one ultrafine filler as defined above;

-Ί- from 0 to 10 parts by weight of at least one thickener as defined above;

-8- from 0 to 10 parts by weight of at least at least one other functional additive as defined above.

These last two varnish compositions are very efficient but may in certain cases have some drawbacks of their advantages; in particular, their method of crosslinking means that they are very sensitive to the environment of use (humidity, light) which can make them difficult to use on textile coating machines.

Under these circumstances, one of the essential objectives of the present invention is to provide new improved anti-fouling varnish compositions for various possibly silicone-based supports, in particular flexible supports (with fiber reinforcement) in particular those coated with silicone elastomers or solid supports in silicone elastomer.

These improvements in the new compositions will be reflected at least with regard to the following two qualities:

1. easier to use compared to previous compositions;

2. very good resistance to soiling and, advantageously, to at least one of the following other qualities:

3. good spreading of the composition on a silicone layer;

4. adhesion to the support and in particular to the coated silicone elastomer layer;

5. absence of coloration but shine;

6. sufficient mechanical strength of the surface layer;

7. easily applicable on various types of supports;

8. and economical.

Another objective of the invention is to provide a simple and economical varnishing process for various silicone or non-formed supports, for example, by fibrous substrates, woven or not and coated with a layer of crosslinked silicone elastomer or by supports. solid at least in part consisting of silicone, using an anti-fouling varnish based on silicon species compatible with silicone elastomers.

Another essential objective of the invention is to provide a composite comprising a support preferably coated with at least one layer of elastomer and covered with a silicone varnish as defined above, for example, a canvas coated with cross-linked silicone elastomer, with high resistance to dirt and low coefficient of friction.

These objectives, among others, are achieved by the present invention which relates, firstly, to a crosslinkable silicone composition useful in particular as a varnish having in particular anti-fouling properties, this composition being of the type of those crosslinkable by polyaddition and comprising :

at least two reactive organosilicon species (A), (B) with each other in the presence of a metallic catalyst (C) (preferably platinum) to allow crosslinking by polyaddition, these two species being constituted by polyorganosiloxanes (POS), optionally at least one particulate component (D) useful in particular as filler;

at least one crosslinking inhibitor (E) useful in particular as a regulator;

optionally at least one solvent (F), optionally at least one adhesion promoter (G);

optionally at least one functional additive (H) to confer specific properties;

characterized in that

- »The species (A) comprises at least one POS resin, preferably a POS resin, having, per molecule, at least one alkenyl group, C2-C6 bonded to silicon;

-&gt; Species (B) comprises at least one POS crosslinking agent, preferably a linear or branched POS, having, per molecule, at least two hydrogen atoms bonded to silicon;

-&gt; the molar ratio R = SiH / SiVi of the species (B) hydrogeno to the species (A) alkenyl is such that R&gt; 2, preferably R&gt; 5 and, even more preferably 6&gt; R&gt; 11.

The silicone varnish according to the invention is advantageous in that it makes it possible to very greatly increase the resistance to soiling, while being easy to use.

The mechanical qualities and the properties of use of the supports varnished by means of the composition according to the invention are not affected.

In addition, insofar as it can be presented in 2 non-reactive parts in isolation, this varnish composition has sufficient stability for delayed use with respect to its manufacture with a storage period compatible with marketing criteria.

The composition according to the invention leads, after spreading and curing (drying / crosslinking) to a surface, thin, protective, hard, smooth, shiny and transparent layer of varnish on a support, preferably coated with a polymer (for example an elastomer. silicone). Within the meaning of the invention, the layer of varnish has for example a substantially homogeneous thickness less than or equal to 15 μm, preferably 5 μm.

It is to the credit of the inventors to have selected POS resins (A) and POS crosslinking agents (B) according to a suitable molar ratio R, these species being crosslinkable by polyaddition in the presence of platinum (C) or other suitable metal.

These compositions are applicable to silicone coatings and provide them in particular:

- a varnished appearance;

- anti-fouling characteristics;

- and a good surface slippage

In the present presentation, reference is made to the following silicone nomenclature to represent the siloxy units ('' Chemistry and technology of silicones Walter NOLL Academie Press 1968 Table 1 page 3):

-&gt; M: R₃ SiOi / 2 with R = Z or Z in formulas (1) and (1) below

- »M^a1c : (R¹) x (R²) y SiOi / 2 with R¹⁼ Z or Z; R²= W or W in formulas (1) and (1) below and x + y = 3; x = l or 2 and y = 1 or 2 - preferably x = 2 and y = l.

-&gt; M^H : (R ')_x(H)_y SiOi 2 with R¹⁼ZouZ in formulas (1) and (1) below; H = Hydrogen and x + y = 3; x = l or 2 and y = 1 or 2 - preferably x = 2 and y = l.

-&gt; D: R₂ SÎO2 / 2 with R = Z or Z in formulas (1) and (1) infra -&gt; D^Alc : R¹ R² SÎO2 / 2 with R¹⁼ Z or Z; R²= W or W in formulas (1) and (1).

-&gt; D^H : R¹HSiO2 / 2 with R^!= Z or Z in formulas (1) and (1) and H = Hydrogen.

-&gt; T: RS1O3 / 2 with R = Z or Z in formulas (1) and (1) infra -&gt; yAlc. R²g (Q_{3/2 with} r²= w or W in formulas (1) and (1) below.

-&gt; Q: S1O4 / 2.

Preferably, the alkenyl W or W is a vinyl, the symbol Ale is then replaced by the symbol Vi.

The choice of the POS resin (A) is an important parameter of the invention. Thus, the preferred family of resins (A) includes all the resins each comprising at least two different siloxy units chosen from those of formulas:

W_at Zb SiO (4_ (_{a +}b)) / 2 (1) in which:

the symbols W, identical or different, each represent an alkenyl group;

the symbols Z, which are identical or different, each represent a non-hydrolyzable monovalent hydrocarbon-based group, free of adverse action on the activity of the catalyst, optionally halogenated and, preferably chosen from alkyl groups as well as from aryl groups, a is 1 or 2 -preferably 1-, b is 0, 1 or 2 and a + b is between 1 and 3, optionally at least part of the other units are units of average formula:

Z_vs SiO (4__vs) / 2 (2) in which Z has the same meaning as above and ca has a value between 0 and 3;

ίο at least one of these two different siloxy units being a T or Q unit.

By alkenyl is meant an unsaturated, linear or branched, substituted or unsubstituted hydrocarbon chain having at least one olefinic double bond, and more preferably a single double bond. Preferably, the alkenyl group has from 2 to 8 carbon atoms, better still from 2 to 6. This hydrocarbon chain optionally comprises at least one heteroatom such as O, N, S.

Preferred examples of alkenyl groups are vinyl, allyl, and homoallyl; vinyl being particularly preferred.

The term “alkyl” denotes a saturated, cyclic, linear or branched hydrocarbon chain, optionally substituted (eg by one or more alkyls), preferably from 1 to 10 carbon atoms, for example from 1 to 8 carbon atoms, better still from 1 to 4 carbon atoms.

Examples of alkyl groups are especially methyl, ethyl, isopropyl, npropyl, tert-butyl, isobutyl, n-butyl, n-pentyl, isoamyl and 1,1-dimethylpropyl.

The alkyl part of the alkoxy radical is as defined above.

The alkyl can be perfluorinated, and the term “perfluorinated alkyl” denotes an alkyl comprising at least one perfluoroalkyl group, preferably having the formula:

2q + 1 in which p represents 0, 1, 2, 3 or 4; q is an integer of 1 to 10; and C_qF2_q+ i is linear or branched. Preferred examples of this radical are: - (CH2) 2 - (CF2) s-CF3 and - (CF₂) ^ - CF₃.

The expression aryl denotes an aromatic hydrocarbon group having from 6 to 18 carbon atoms, monocyclic or polycyclic and preferably monocyclic or bicyclic. It should be understood that, in the context of the invention, by polycyclic aromatic radical is meant a radical having two or more aromatic rings, condensed (orthocondensed or ortho and pericondensed) to each other, that is to say having, two by two, at least two carbons in common.

By way of example of aryl, there may be mentioned eg the phenyl radicals.

Advantageously, the number of M units / number of Q and / or T units ratio is from 4/1 to 0.5 / 1. The number of D units / number of Q and / or T units ratio is 100/1 to 0.

The resins (A) preferably have a Ο / Si molar ratio of greater than or equal to 0.75; when said ratio is less than or equal to 1, said resins are generally liquid; more viscous products have a Ο / Si ratio close to 1; solid thermoplastic or high softening point resins are obtained when said ratio greater than 1.

In accordance with the invention, preference may be given for the resins (A) to those comprising molecules consisting of siloxy M units.^Alc, M and Q and / or molecules consisting of siloxy units M, D^Alc and Q.

These resins (A) are well known and commercially available branched organopolysiloxane oligomers or polymers. They can be in the form of solutions, preferably siloxane. As examples of branched oligomers or organopolysiloxane polymers, mention may be made of MQ resins, MDQ resins, TD resins and MDT resins, the alkenyl functions possibly being carried by the M, D and / or T units. As examples of resins which are particularly suitable, mention may be made of alkenylated (eg vinyl) MDQ or MQ resins, these alkenyl (eg vinyl) groups being carried by the M and / or D units.

Preferably, the POS resin (A) has a weight content of alkenyl radical (s) of between 0.1 and 20% by weight and, preferably, between 0.2 and 10% by weight.

According to one variant, the composition which comprises species (A) comprises at least one hyperalkenylated POS (A) different from a resin, this hyperalkenylated POS (A) comprising siloxyl units of formula:

W_at„Z_b„SiO₍₄_ (a + b)) / 2 (1) in which:

the symbols W, which are identical or different, each represent an alkenyl group;

- the symbols Z, which are identical or different, each represent a non-hydrolyzable monovalent hydrocarbon group, free from adverse action on the activity of the catalyst, optionally halogenated and, preferably chosen from alkyl groups as well as from aryl groups,

- a is 1 or 2, b is 0, 1 or 2 and a + b is between 1 and 3,

- optionally at least some of the other units are units of average formula:

Z_vs„SiO₍₄._VS) / 2 (2) where Z has the same meaning as above and ca has a value between 0 and 3;

this hyperalkenylated POS (A) preferably comprising molecules of the following formula:

(M^Alc) n (D) p (D^Alc) q (M)_m in which:

p&gt; 0, q&gt; 0, n + q&gt; 3, preferably n + q&gt; 4;

n = 0, 1 or 2; m = 0.1 or 2.

The hyperalkenylated POS (A) can be very predominantly formed of units of formula (1) or can additionally contain units of formula (2). Likewise, they can have a linear structure. Their degree of polymerization is preferably between 2 and 5000. Their content of alkenyl groups expressed in moles per 100 g of POS is&gt; 0.035, preferably&gt; 2.

Z is generally chosen from methyl, ethyl and phenyl radicals, at least 60 mol% of the Z radicals being methyl radicals.

Examples of siloxyl units of formula (1) are the vinyldimethylsiloxane unit, the vinylphenylmethylsiloxane unit and the vinylsiloxane unit.

Examples of siloxyl units of formula (2) are S1O4 / 2, dimethylsiloxane, methylphenylsiloxane, diphenylsiloxane, methylsiloxane and phenylsiloxane units.

Examples of POS (A) are dimethylpolysiloxanes with dimethylvinylsilyl ends, methylvinyldimethylpolysiloxanes with trimethylsilyl ends, methylvinyldimethylpolysiloxanes copolymers with dimethylvinylsilyl ends, cyclic methylvinylpolysiloxanes.

The dynamic viscosity r | d of this POS (A) is between 0.01 and 1000 Pa.s, preferably between 0.01 and 500 Pa.s.

Preferably, the POS (A) comprises at least 98% of siloxyl units D⁰': R2S1O2 / 2 with R corresponding to the same definition as Z, this percentage corresponding to a number of units per 100 silicon atoms.

Preferably, the alkenyl units W are vinyls carried by siloxyl units D and optionally M and / or T.

As regards the species (B), it preferably comprises at least one hydrogenated POS (B), this POS (B) comprising siloxyl units of formula:

H_d L_e SiO ^ - ^ + e)) ^ (3) where:

- H is hydrogen,

- the symbols L, which are identical or different, each represent a non-hydrolyzable monovalent hydrocarbon-based group, free from adverse action on the activity of the catalyst, optionally halogenated and, preferably chosen from alkyl groups as well as from aryl groups,

- d is 1 or 2, e is 0, 1 or 2 and d + ea a value between 1 and 3; optionally, at least some of the other units being units of average formula:

L_gSiO (4-g) / 2 (4) in which L has the same meaning as above and g has a value between 0 and 3;

this hydrogenated POS (B) corresponding, preferably, to molecules of the following formulas (5) and / or (6):

(M^H) r (D) s (D^H) t (M)_u (5) in which:

r = 0-2;

s = 0-50;

t = 0-70;

u = 0-2;

r&gt; 0; s&gt; 0; t&gt; 0; u&gt; 0; r + t&gt; 3 (M^h)_{(2w + 2)} Q_w (6) formula in which:

w = 1 to 6, preferably 1 to 4;

(B) being preferably chosen from the following compounds:

-&gt; compounds of formula (5) with t = 0, u = 0, r = 2 and s = 1 to 20;

-&gt; compounds of formula (5) with t = l70, u = 0, r = 2ets = l50; -&gt; compounds of formula (5) with t = 1 to 70, u = 2, r = 0 and s = 1 to 50;

-&gt; compounds of formula (6) with w = 1 to 6, preferably 1 to 4;

-&gt; and their mixtures.

As an example of POS (B), mention may be made of poly (dimethylsiloxane) (methylhydrogenosiloxy) OC, ω dimethylhydrogenosiloxane, hydrogenosiloxane resins of M'Q type.

POS (B) can be formed only from units of formula (3) or additionally include units of formula (4).

POS (B) can have a linear, branched, cyclic or network structure.

The dynamic viscosity of this POS (B) is between 5 and 1000 mPa.s, preferably between 10 and 100 mPa.s.

Group L has the same meaning as group Z above.

Examples of units of formula (3) are: H (CH3)₂SiOi / 2, HCH3S1O2 / 2,

H (C₆H₅) SiO₂/2.

The examples of units of formula (4) are the same as those given above for the units of formula (3).

Examples of POS (B) are:

- dimethylpolysiloxanes with hydrogenodimethylsilyl ends,

- copolymers containing (dimethyl) - (hydrogenomethyl) polysiloxanes with trimethylsilyl ends,

- Copolymers containing dimethyl-hydrogenomethylpolysiloxane units with hydrogenodimethylsilyl ends,

- Hydrogenomethylpolysiloxanes with trimethylsilyl ends,

- cyclic hydrogen methylpolysiloxanes,

- hydrogenosiloxane resins comprising siloxyl units M: R₃SiO_1/2, Q: SiO_4/2 and / or T: RSiO_3/2, possibly D: -R₂SiO_{2 2}, with R = H or corresponding to the same definition as L.

Advantageously, the concentration Cb in species (B) (in parts by weight per 100 parts by weight of (A)) is such that Cb&gt; 5, preferably Cb&gt; 10, more preferably Cb&gt; 20, and, even more preferably 200 &gt; Cb&gt; 30

As other examples of ZZ or L hydrocarbon groups, monovalent capable of being present in the aforementioned POS (A) (A) / (B), there may be mentioned: methyl, ethyl; n-propyl; i-propyl, n-butyl; i-butyl; t-butyl; chloromethyl; dichloromethyl; α-chloroethyl; oc, β-dichloroethyl; fluoromethyl; difluoromethyl; a, β-difluoroethyl; trifluoro-3,3,3-propyl; trifluoro cyclopropyl; trifluoro-4,4,4 butyl; hexafluoro-3,3,5,5,5,5 pentyl; β-cyanoethyl, γ-cyanopropyl; phenyl; p-chlorophenyl; m-chlorophenyl; dichloro-3,5-phenyl; trichlorophenyl; tetrachlorophenyl; 0-, p- or m-tolyl; oc, oc, α-trifluorotolyl; xylyl such as dimethyl2,3 phenyl; dimethyl-3,4-phenyl.

These groups can optionally be halogenated, or else be chosen from cyanoalkyl radicals.

The halogens are, for example, fluorine, chlorine, bromine and iodine, preferably chlorine or fluorine.

POSs (A) (A) or (B) can consist of mixtures of different silicone oils.

The polyaddition reaction specific to the crosslinking mechanism of the varnish according to the invention is well known to those skilled in the art. It is also possible to use a catalyst (C) in this reaction. This catalyst (C) can in particular be chosen from platinum and rhodium compounds. It is in particular possible to use the complexes of platinum and of an organic product described in US-A-3,159,601, US-A-3,159,602, US-A-3,220,972 and European patents EP- A-0 057 459, EP-A-0 188 978 and EP-A-0 190 530, the complexes of platinum and vinylated organosiloxanes described in the patents US-A-3,419,593, US-A-3,715,334 , US-A-3,377,432 and US-A-3,814,730. The generally preferred catalyst is platinum. In this case, the quantity by weight of catalyst (C), calculated by weight of platinum metal, is generally between 2 and 400 ppm, preferably between 5 and 100 ppm based on the total weight of the POS (A &amp; A ') , (B &amp; B ').

The optional particulate component (D) is, according to an advantageous alternative, selected from the group of powders comprising particles, preferably substantially spherical, the diameter of which is preferably 1 to 2 times the thickness of the layer of varnish capable of be produced from said composition and the density of which is advantageously comparable to that of the silicone composition.

More preferably still, the particulate component (D) that it comprises is selected:

• in the group of non-aggregated particles (possibly hollow or even expandable), in powder or in suspension in suitable solvents, and chosen in particular:

* in the group of (co) polyamides powders - preferably (co) polyamides 6, 12 and 6/12 - comprising particles of substantially rounded shape and of average diameter &lt;t&gt; md between 0.1 and 50 pm , preferably between 0.5 and 20 μm and, more preferably still between 1 and 15 μm;

* and / or in the group of silica powders having an average particle diameter &lt;ï&gt; md close to or less than 5 μm; these silicas being advantageously colloidal silicas, combustion silicas, and precipitated silicas or their mixtures;

* and / or from the group of metal oxides, preferably of titanium, cerium or aluminum, Al2O3 or Al (OH) 3 (hydrated alumina), or else mica powders;

• in the group of structured particles in powder or in suspension in suitable solvents, in particular in the group of reinforcing silica powders such as treated pyrohydrolysis silica;

• and in their mixtures.

According to a preferred characteristic of the invention, the particulate component (D) when it is from the group of (co) polyamide powders, is present in an amount of 0.1 to 20% w / w relative to the total mass of the composition. of varnish. This limited quantity reflects the fact that this component cannot be assimilated to a filler influencing the mechanical qualities and the properties of use of the varnished support.

According to another preferred characteristic of the invention, the particulate component (D) when it is from the group of silicas, is present in an amount of 0.001 to 5% w / w relative to the total mass of the composition.

These fillers (D) can advantageously be treated with a compatibilizer such as, for example, organosilanes or siloxanes or silazanes

From the weight point of view, it is preferred to use an amount of this component of 0.001 to 10 parts, preferably between 1 and 5 parts.

The inhibitors of the addition reaction (E) are chosen from the following compounds:

- polyorganosiloxanes, advantageously cyclic and substituted by at least one alkenyl, tetramethylvinyltetrasiloxane and divinyltetramethyledisiloxane being particularly preferred,

- pyridine,

- organic phosphines and phosphites,

- unsaturated amides,

- alkylated maleates,

- and acetylenic alcohols.

These acetylenic alcohols (Cf. FR-B-1 528 464 and FR-A-2 372 874), which form part of the preferred thermal hydrosilylation reaction blockers, have the following formula:

R - (R ') C (OH) - C ξ CH formula in which:

- R is a linear or branched alkyl radical, or a phenyl radical;

- R 'is H or a linear or branched alkyl radical, or a phenyl radical;

- the radicals R, R 'and the carbon atom located at oc of the triple bond which may optionally form a ring;

- the total number of carbon atoms contained in R and R 'being at least 5, preferably 9 to 20.

Said alcohols are preferably chosen from those exhibiting a boiling point of greater than 250 C. There may be mentioned by way of examples:

- ethynyl-1-cyclohexanol 1;

- 3-methyl-1-dodecynol-3;

- trimethyl-3,7,11 dodécyne-1 ol-3;

- Dipheny 1-1,1 propyne-2 ol-1;

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

- methyl-3 pentadecyne-1 ol-3.

These α-acetylenic alcohols are commercial products.

Such an inhibitor (E) is present in an amount of 3,000 ppm at most, preferably in an amount of 100 to 2,000 ppm relative to the total weight of the organopolysiloxanes (A) and (B).

According to another preferred characteristic (but nevertheless optional), the composition according to the invention can be provided in the form of a solution in at least one solvent (F), preferably chosen from the group comprising siloxane solvents - in particular the HexaMethylDiSiloxane (HMDS) -, organic solvents, advantageously aromatics - in particular xylene - and / or alkanes - in particular white spirit® ... and their mixtures.

Advantageously, since it comprises solvent (F), the composition according to the invention can be characterized in that it is obtained by using a solution of POS resin (A) and in that the solvent (F ) is at least in part that of this POS resin solution (A).

Preference can be given according to the invention to compositions whose concentration Cf in solvent F (expressed in w / w relative to the final mixture) is such that: -&gt; 10 &lt;C_F &lt; 80

- "preferably 15 &lt;Cf &lt;65 -&gt; and more preferably still 20 &lt;Cf &lt;60.

When necessary, the choice of the adhesion promoter (G) depends on the substrate where the varnish is applied. These are generally functional alkoxylated organosilanes. These silanes are often associated with catalysts which promote their condensation. It may for example comprise one or more alkoxylated organosilanes such as VTMS, γ-methacryloxypropyltrimethoxysilane and / or one or more epoxidized organosilicon compounds such as GLYMO and / or one or more chelates and / or metal alkoxides such as tertio-titanate. -butyl.

Furthermore, when it is integrated into the formula, this adhesion promoter (G) is preferably present in an amount of 0.1 to 10%, preferably 0.5 to 5% and more preferably still 1 to 2.5 % by weight relative to all the constituents of the preparation.

Regarding the possible functional additives (H) that may be used, they may be covering products such as, for example, appearance modifiers (pigments / dyes), stabilizers, protectors (antifungal, fire retardant , antiUV, thermal, etc.), hydrophilizers, thickeners, plasticizers or fillers, etc. When the preparations used in the process according to the invention comprise a filler, it is preferably inorganic. It can consist of products chosen from siliceous materials (or not). Siliceous fillers such as diatomaceous earth or ground quartz can thus be used. Moreover, examples of non-siliceous fillers which can be used alone or as a mixture are carbon black, titanium dioxide, aluminum oxide, hydrated alumina, expanded vermiculite, zirconia, a zirconate, unexpanded vermiculite. , calcium carbonate, zinc oxide, mica, talc, iron oxide, barium sulfate and slaked lime. These fillers have a particle size generally between 0.01 and 10 μηι and a BET surface area of ​​less than 100 m²/ g. It should be noted that the pigmentation can be supplemented, for example at the time of use.

The viscosity of the uncrosslinked liquid varnish as it is applied to the support can be adjusted by dilution with solvents depending on the deposition methods used. Thus, the dynamic viscosity η (mPa.s at 25 ° C) of the composition diluted in a solvent before application is for example:

preferably and more preferably still &lt;η &lt;500, &lt;η &lt;200, &lt;η &lt;150

The dynamic viscosity at 25 ° C., of all the silicone polymers considered in the present disclosure, can be measured using a BROOKFIELD viscometer, according to the AFNORNFT 76 102 standard of February 1972. In the case of very fluid products, the viscosity in question in the present description 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 low enough for the measured viscosity to be independent of the speed gradient.

The preferred varnish composition is of the type of those which can be crosslinked by polyaddition and comprises:

o A- 100 parts by weight of dry POS resin (A), preferably of formula MM^V1Q, ο B- 35 to 150 parts by weight of POS (B) preferably of formula (M^H)_v Q with v = l at (eg 4), o C- 0.0005 to 0.1 by weight of Pt as catalyst (C), o Dl- 0 to 50 parts by weight of at least one particulate component (Dl) selected from the group of powders of (co ) polyamides, o D2- 0 to 50 parts by weight of at least one particulate component (D2) selected from the group of silica powders, o D3- 0 to 50 parts by weight of at least one particulate component (D3) chosen from the group of reinforcing silica powders, o D4- 0 to 50 parts by weight of at least one particulate component (D4) chosen from the group of powders of metal oxides, preferably of titanium, cerium or aluminum Al2O3 (hydrated alumina), or else of mica powders, ο E- 0.01 to 1, parts by weight of at least one crosslinking inhibitor (E) useful in particular as a regulator o F- 0 to 800 parts by weight at least one solvent (F), o G - 0 to 5 parts by weight of at least one adhesion promoter (G);

o H- 0 to 5, preferably 0 to 10 parts by weight of at least one functional additive (H), (for example 0 to 3 parts by weight of at least one thickener).

For conservation reasons, the varnish composition is advantageously presented in the form of an at least two-component system, the mixture of which is capable of rapidly crosslinking when hot by polyaddition. The ingredients are then distributed in the different parts according to the rules of a person skilled in the art; in particular the catalyst is separated from the component which comprises the hydrogenosiloxanes.

Taking into account its ease of obtaining, its low cost and its antifouling properties, the silicone varnish composition according to the invention is likely to have outlets in numerous fields of application and in particular, mention may be made of: supports with a woven or non-optionally silicone fibrous core (ie coated on at least one of its faces with at least one layer of elastomer);

or alternatively supports constituted by solid pieces of silicone and / or silicone.

According to another of its aspects, the invention relates to a process for varnishing a support, characterized in that the composition as defined above is applied as a varnish, in particular anti-fouling, on the surface. surface of said support.

According to one variant, the support comprises silicone, preferably elastomeric silicone, this silicone advantageously forming at least one coating of said support and the varnish is applied to the surface of the silicone. Clearly, it may be a support at least partly coated with at least one layer of elastomer or with a silicone part.

According to another variant, the process for varnishing a support, in particular a coated textile, is characterized in that the composition as defined above is applied as a varnish, in particular anti-fouling, on the surface of said support, this surface comprising at least one non-silicone (co) polymer, preferably selected from the group comprising: polyamides, polyolefins (for example PVC), polyesters, their copolymers and their mixtures.

Preferably, this process essentially consists of:

- depositing the support using the varnish composition as defined above,

- to evaporate the solvent

- And to crosslink the layer of varnish, optionally by thermally activating the crosslinking.

According to an advantageous arrangement of the invention, the composition of the varnish is applied to the support according to a deposition rate less than or equal to 15 g / m², preferably between 0.5 and 5 g / m².

Concerning the aspect, the use of the varnish composition according to the invention; it can for example be applied to a support by any suitable coating or transfer means (for example doctor blade, coating cylinder, gravure printing, dynamic screen printing, brush, spraying: gun, etc.).

The crosslinking of the liquid silicone varnish composition applied to the support to be coated is generally activated, for example by heating the surface of the support thus coated, to a temperature between 50 and 200 ° C, obviously taking into account the maximum resistance. from support to heat.

The activation means are of the type of those known and suitable for this purpose, for example thermal or IR radiation

Further details will be given in this regard in the examples which follow.

The present invention also relates to the varnished (or composite) support endowed with anti-fouling properties and capable of being obtained by the process as referred to above. This composite is characterized in that it comprises o a preferably flexible support, and more preferably still chosen from the group comprising:

=&gt; textiles, =&gt; non-woven fibrous supports,

G&gt; polymer films, in particular polyester, polyamide, polyolefin, polyurethane, silicone polyvinyl chloride, o optionally a coating integral with at least one of the surfaces of the support and consisting of at least one layer of silicone elastomer and / or at least one other (co) polymer, o and at least one varnish layer comprising the composition as defined above.

The flexible supports concerned by the invention can be, among others, those mentioned above.

According to one possibility of implementation, the composite according to the invention can be characterized in that the support comprises at least one coating on at least one of its faces, this coating comprising at least one layer of silicone elastomer and / or at least one other (co) polymer and in that the varnish has a thickness less than or equal to 15 μm, preferably 5 μm.

According to another possibility of implementation, the composite according to the invention (capable of being obtained by the above-defined process), can be characterized in that it comprises:

a solid support optionally made of silicone and / or at least partially coated with silicone, the silicone preferably being a silicone elastomer, and at least one layer of varnish comprising the composition according to the invention as defined above.

The silicone coating is optional, for example since the support itself is silicone.

Advantageously, the composite according to the invention can include a support comprising at least one material chosen from the group comprising:

- glass in bulk form or in the form of fibers,

- ceramics in bulk form or in the form of fibers,

- natural or synthetic polymers, in bulk form, in the form of fibers, or in the form of films, in particular polyester, polyamide, polyurethane, polyvinyl chloride or silicone,

- cellulosic or lignocellulosic materials without bulk or fibrous form, in particular paper, cardboard or the like,

- and their associations.

The fibrous supports intended to be coated and then varnished in accordance with the invention can be, for example, fabrics, nonwovens or knits or more generally any fibrous support comprising fibers chosen from the group of materials comprising: glass, silica, metals, ceramic, silicon carbide, carbon, boron, natural fibers such as cotton, wool, hemp, flax, artificial fibers such as viscose, or cellulosic fibers , synthetic fibers such as polyesters, polyamides, polyacrylics, chlorofibers, polyolefins, synthetic rubbers, polyvinyl alcohol, aramids, fluorofibers, phenolics, silicones, etc.

As preferred examples of fibrous supports, mention may be made of fabrics of glass, polyester, polyamide, polyurethane, polyolefin, polyvinyl chloride or silicone, or even papers, cardboard or the like.

In addition to flexible textile supports coated with silicone, the anti-fouling varnish according to the invention can be applied to plastic films (for example of protective packaging), eg made of polyester, polyurethane, polyamide, polyolefin (polyethylene, polypropylene), polyvinyl chloride, or silicone. These supports being optionally activated to promote anchoring of the varnish; an activation treatment is, for example, the Corona treatment.

The solid supports concerned by the invention can be, among others, parts chosen from the group comprising:

- furniture,

- cladding,

- advertising screens,

- windbreaks,

- compensators (flexible sealing sleeves for pipes),

- or filter panels.

According to another of its subjects, the invention encompasses manufactured articles comprising at least one composite capable of being obtained by the process or at least one composite according to the invention as defined above.

Among these manufactured articles is any article comprising at least one composite capable of being obtained by the process or at least one composite according to the invention as defined above.

According to yet another of its subjects, the invention comprises the use of the above-defined composition, as a varnish, in particular anti-fouling, on a silicone or non-silicone surface, in particular for manufacturing manufactured articles.

The silicone capable of forming the coating or the solid part on which the varnish composition according to the invention is capable of being applied, may be an elastomer based on polyorganosiloxane (s), which can be crosslinked or at least partially crosslinked, and preferably chosen from:

- polyaddition or polycondensation RTV silicones,

- and / or peroxide or polyaddition EVC silicones,

- and / or LSR polyaddition silicones.

The anti-fouling varnish obtained from the composition, as defined above, is applied to the layer (s) (upper (s)) of silicone elastomer.

The expressions RTV, LSR, EVC are well known to those skilled in the art: RTV is the abbreviation for Room Temperature Vulcanizing; LSR is the abbreviation for Liquid Silicone Rubber; EVC is the abbreviation of: Hot Vulcanizable Elastomer.

In practice, the invention relates more precisely to the supports (for example textiles such as those used for the manufacture of airbags '') coated on one and / or the other of their faces with a layer of silicone elastomer. crosslinked RTV, EVC or LSR, itself coated with a coating of anti-fouling silicone varnish as defined above.

The problem of providing anti-fouling properties is particularly acute with regard to these crosslinked silicone elastomer parts or coatings since, as has already been indicated above, the latter have the characteristic of having a sticky feel.

The polyorganosiloxanes, main constituents of the adhesive layers of crosslinked elastomers or of the solid supports / parts on which the varnish according to the invention is capable of being applied, can be linear, branched or crosslinked, and comprise hydrocarbon radicals and / or reactive groups such as, for example, hydroxyl groups, hydrolyzable groups, alkenyl groups and hydrogen atoms. It should be noted that the polyorganosiloxane compositions are amply described in the literature and in particular in the work by Walter NOLL: Chemistry and Technology of Silicones, Academie Press, 1968, 2nd edition, pages 386 to 409.

It is possible to use a wide variety of monocomponent or bicomponent compositions crosslinking by polyaddition or polycondensation reactions, in the presence of a metal catalyst and optionally of an amine and a crosslinking agent.

Bicomponent or mono-component polyorganosiloxane compositions crosslinking at room temperature (RTV) or at heat (EVC) by polyaddition reactions, essentially by reaction of hydrogenosilyl groups on alkenylsilyl groups, generally in the presence of a metal catalyst, preferably platinum, are described, for example, in US-A-3,220,972, 3,284,406, 3,436,366, 3,697,473 and 4,340,709.

The two-component or one-component polyorganosiloxane compositions crosslinking at room temperature (RTV) by polycondensation reactions under the action of humidity, generally in the presence of a metal catalyst, for example a tin compound are described for example for one-component compositions in US-A-3,065,194, 3,542,901, 3,779,986, 4,417,042, and in FR-A-2,638,752, and for two-component compositions in US-A3 patents 678,002 , 3 888,815, 3,933,729 and 4,064,096. The polyorganosiloxanes entering into these compositions are in general linear, branched or crosslinked polysiloxanes. These RTV polyorganosiloxane compositions which crosslink by polyaddition or polycondensation reactions, advantageously have a viscosity at 25 ° C. at most equal to 100,000 mPa.s and, preferably, between 5,000 and 50,000 mPa.s.

It is possible to use RTV compositions crosslinking at room temperature by polyaddition or polycondensation reactions, having a viscosity at 25 ° C greater than 100,000 mPa.s, such as that lying in the range from one value greater than 100,000 mPa.s to 300,000 mPa.s; this modality is recommended when it is desired to prepare filled curable compositions in which the filler (s) used has (tend) to separate by sedimentation.

It is also possible to use compositions crosslinking by heat by polyaddition reactions and more precisely so-called polyaddition EVC type compositions, having a viscosity at 25 ° C. at least equal to 500,000 mPa.s and, preferably between 1 million mPa.s and 10 million mPa.s and even more.

They may also be compositions which can be hardened at high temperature under the action of organic peroxides such as 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, t-butyl perbenzoate, cumyl peroxide, peroxide. of di-t-butyl. The polyorganosiloxane or gum entering into such compositions (simply called EVC type) then consists essentially of siloxyl units (Γ), optionally associated with units (II ') in which the remainder Z ° represents a C2 - Cg alkenyl group and where x is equal to 1. Such EVCs are for example described in US Patents 3,142,655, 3,821,140, ​​3,836,489 and 3,839,266). These compositions advantageously have a viscosity at 25 ° C. at least equal to 1 million mPa.s and, preferably, between 2 million and 10 million mPa.s and even more.

Other polyorganosiloxane compositions which can be sprayed with the silicone varnish composition according to the invention are those, single-component or two-component, crosslinking under heat by polyaddition reactions, called LSR compositions. These compositions correspond to the definitions given above with regard to the preferred compositions called RTV, except with regard to their viscosity which this time is in the range going from a value greater than 100,000 mPa.s to more than 500,000. mPa.s.

Without this being limiting, the silicone elastomer coatings to which the anti-fouling varnish according to the invention can be applied are more especially coatings obtained from cold vulcanizable RTV silicone elastomer compositions, in particular of the two-component type (RTV 2), by polyaddition.

The examples presented demonstrate the performance of the varnish according to the invention and its advantages over the prior art.

EXAMPLES:

Experimental aspects

Textile support

The support sample is a coating of RTV II applied to a textile support of the glass fabric type. The thickness of the coating is sufficient (approx. 250 μm) for the coated surface to be smooth and for the nature of the fabric used to become completely screened.

The composition of RTV-II used is RHODORSIL® TCS 7534 sold by the company Rhodia Silicones. In the laboratory, its crosslinking on the support considered is carried out by staying for 2 minutes in a ventilated oven maintained at 160 ° C.

Vernissage

In the laboratory, the varnish is applied to the silicone support using a Mayer bar suitable for a deposit of the order of 5 g / m² ; the crosslinking is carried out by staying in a ventilated oven at 180 ° C. for 2 minutes.

To better adjust the surface weight of deposited varnish, the latter can be diluted with a solvent; HexaMethylDiSiloxane is advantageously used in a blend or not with White Spirit.

Characterization of the varnish

The quality of the crosslinking combined with the appreciation of the good coverage of the fabric are evaluated by measuring the surface slip. We can have a qualitative assessment resulting from the observation when we try to slide the sample on a glass plate or proceed to a measurement of the For this we determine the Coefficient of Friction (CoF) of the varnish complex in contact with glass plate ; The operation is carried out in a plane geometry with a contact surface of 10x5cm with a load of 200g.

Soiling resistance test

The quality of the covering of the silicone fabric with the varnish and its resistance to soiling is judged by means of a carbon black fouling test; the carbon black is deposited on the sample to be tested by means of a brush and it is spread by wiping with a veil of cellulose wadding. The following reference board is used for dimensioning.

<img file="FR2894591A1_D0006.tif" />

<img file="FR2894591A1_D0007.tif" />

Poly Addition Anti-Foul Silicone Varnish

Raw materials

Al resin

MD silicone resin^V1Q at 60% in xylene where:

- groups Μ = [Ο1 / 2 Si (ί'Ηψ]

- groups D^V1 = [Ο1 / 2 Si CH3 C2H5]

- Q = [Ο4 / 2 Si] groups and bearing on average 2.5% -CFUCFL groups

A2 resin

MM silicone resin^V1Q at 60% in xylene and comprising:

- groups Μ = [Ο1 / 2 Si (CH;);]

- M groups^V1 = [Ο1 / 2 Si (CH;)₂ C2H5]

- Q = [Ο4 / 2 Si] groups and bearing on average 2.5% of -CH = CH2 groups

Crosslinker B1

A PolyDiMethylSiloxane with [Ο1 / 2 Si (CH3) 2 H] terminations which titrated to 5.5% of SiH groups by weight.

Crosslinker B2

A PolyOrganoSiloxane with [Ο1 / 2 Si (CH3) 2 H] terminations which titrated to 25% of SiH groups by weight

Crosslinker B3

A PolyMethylHydrogenosiloxane with [Ο1 / 2 Si (CH3) 3] terminations with a viscosity of 20 mPa.s

Catalyst C

A Karsdetd complex assaying 10% by weight of platinum metal.

Crosslinking inhibitor E also referred to below as Regulator

The Ethyny lCy cloHexano 1.

DI load

PolyAmide 12 beads of ΙΟμηι of average diameter marketed under the reference Orgasol® 2001 EXD NAT1 by the company Arkéma.

Load D2

A pyrohydrolysis silica displaying 260m²/ g and treated in an amount of 2.5% expressed as carbon, marketed under the reference Aerosil R812 by the company Degussa.

Examples

Examples 1 to 7

The compositions of Table 1 below are applied under the conditions described.

The slippiness and the resistance to soiling are qualitatively evaluated according to the board presented.

<td></td><td colspan="7">parts by weight</td>

<td>Al resin</td><td> 100</td><td> 100</td><td> 100</td><td> 100</td><td></td><td></td><td></td>

<td>A2 resin</td><td></td><td></td><td></td><td></td><td> 100</td><td> 100</td><td> 100</td>

<td>Crosslinker B1</td><td> 12</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Crosslinker B2</td><td> 5,5</td><td> 42</td><td> 100</td><td></td><td> 6</td><td> 18</td><td> 42</td>

<td>Crosslinker B3</td><td></td><td></td><td></td><td> 55</td><td></td><td></td><td></td>

<td>Catalyst C</td><td> 0,1</td><td> 0,1</td><td> 0,1</td><td> 0,1</td><td> 0,1</td><td> 0,1</td><td> 0,1</td>

<td>Inhibitor / Regulator E</td><td> 0,1</td><td> 0,1</td><td> 0,1</td><td> 0,1</td><td> 0,1</td><td> 0,1</td><td> 0,1</td>

<td>Sliding</td><td>NOT</td><td>NOT</td><td>o</td><td>NOT</td><td>NOT</td><td>NOT</td><td>O</td>

<td>Soiling</td><td> 2-3</td><td> 4</td><td> 4</td><td> 3</td><td> 2</td><td> 3</td><td> 4</td>

Table 1

These tests teach us that a high level of crosslinking agent B is necessary to obtain a varnish which offers both good surface slip and high resistance to soiling. Furthermore, Resin A2 appears to require less crosslinking agent than Resin A1 and crosslinking agent B2 appears to be the most advantageous.

Examples 8 to 10

The compositions of Table 2 below are applied under the conditions described. The coefficient of friction (CoF) and resistance to soiling are qualitatively evaluated according to the board presented.

<td></td><td colspan="3">parts by weight</td>

<td>Al resin</td><td> 70</td><td></td><td></td>

<td>A2 resin</td><td></td><td> 70</td><td> 70</td>

<td>Crosslinker B2</td><td> 30</td><td> 30</td><td> 30</td>

<td>DI load</td><td> 1</td><td> 1</td><td> 1</td>

<td>Load D2</td><td></td><td></td><td> 10</td>

<td>Catalyst VS</td><td> 0,02</td><td> 0,02</td><td> 0,02</td>

<td>Inhibitor/ Regulator E Regulator</td><td> 0,02</td><td> 0,02</td><td> 0,02</td>

<td>CoF</td><td> 0,6</td><td> 0,5</td><td> 0,4</td>

<td>Soiling</td><td> 2</td><td> 4</td><td> 4-5</td>

Table 2

These tests confirm the benefit of Resin A2 over Resin A1 and show the advantage when using DI &amp; D2 fillers.