FR2805274A1 - Pigment especially for use in paints is coated with a fluorinated block - Google Patents

Abstract

A pigment coated with a copolymer, which contains at least one fluorinated block. Composition (C) comprising a support based on a pigment and a layer coating at least part of the support and based on a block copolymer comprising at least one fluorinated block. INDEPENDENT claims are included for: (i) a procedure for the preparation of composition (C) characterized by contacting the support and the copolymer and precipitating the copolymer onto the support; (ii) colored pigments comprising composition (C); (iii) colored plastics , rubbers, ceramics, paper etc. containing composition (C); and (iv) paints containing composition (C).

Description

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COMPOSITION BASED ON A PIGMENTARY CARRIER PRESENTING
A BLOCK COPOLYMER IN SURFACE. ITS USE AS
PIGMENT COLORS ESPECIALLY IN PAINTS
RHODIA CHEMISTRY
The present invention relates to a composition based on a pigment carrier having a surface block copolymer, its method of preparation and its use as a colored pigment especially in paints.

 The inorganic pigments or organic coloring are widely used in many industries including those of paints, plastics and ceramics. However, it still appears important to further improve their properties such as thermal resistance, durability, measured by acid resistance or ultraviolet resistance. Moreover, there is also a need for pigments that can be used in paints. The known pigments for paints generally undergo treatments fixing organic products of the hydrophobic type on their surface, but these products tend to solubilize in the paint and to migrate to the interfaces of the film or film of paint when it is dried. which can cause a detachment of this film.

 The object of the invention is therefore the development of pigment type compositions suitable for use in painting.

 Another object of the invention is to provide pigment compositions which have good properties as regards heat resistance or durability in their application medium, for example in paints or in plastics.

 For this purpose, the composition according to the invention is characterized in that it comprises: a support based on a pigment; a layer at least partly coating said support and based on a block copolymer comprising at least one fluorinated block.

 The invention also relates to a method for preparing such a composition which is characterized in that the support is put in contact with the block copolymer and the copolymer is precipitated on the support.

 Other features, details and advantages of the invention will appear even more fully on reading the description which follows, as well as various concrete but non-limiting examples intended to illustrate it.

 The composition of the invention firstly comprises a support based on a pigment. By pigment is meant any product, of inorganic or organic type and in solid form, capable of being able to color. Generally this pigment has a

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 particle size of not more than 100 μm. Preferably, this particle size is at most 5 m and even more preferably at most 2 m.

 By way of example, mention may be made, as pigments, of the anthraquinone type, dioxazine, flaranthrone, idanthrone, quinacridone, optionally halogenated copper phthalocyamine, isoindolinone, azomethine, perylene, arylamide, diarylide, azo, dinitraniline, naphthol, toluidine, complex iron, lead chromates, chromium, cobalt, nickel complexes, copper, nickel and cobalt amine complexes, iron compounds such as oxides, titanium compounds such as nickel titanates, and carbon blacks carbon.

 Mention may also be made of inorganic pigments chosen from silicoaluminates, calcium carbonate and titanium oxide.

 In the context of the present invention, the inorganic pigment used may be rare earth sulphides, especially those having a sesquisulphide structure Ln2S3, Ln denoting one or more rare earths. Rare earth means the elements of the group consisting of yttrium and the elements of the periodic classification of atomic number inclusive between 57 and 71. Reference may in particular be made to this subject in the patent application EP-203838 for this type. sulphides.

 According to a particular embodiment of the invention, the pigment is a rare earth sulphide which contains at least one alkaline and / or alkaline earth element of which at least part is included in the crystal lattice of said sulphide.

 Reference may be made here to the teaching of the European patent application EP-A-545746. It may be recalled that the alkaline element may be chosen in particular from lithium, sodium or potassium. Of course, the sulfide may include several alkali or alkaline earth elements.

 According to one variant, the alkaline or alkaline-earth element is included essentially or totally in the crystal lattice.

 The sulphide may be more particularly a sesquisulphide.

 The sesquisulphide may in particular have a cubic crystallographic structure of Th3P4 type, which has gaps in the cation network; this lacunary structure can be symbolized by giving the sesquisulfides the formula M10,66 [] 1,33 S16 (see in this connection, WH ZACHARIASEN, "Crystal Chemical Studies of the 5f-Series of Elements." Ce2S3-Ce3S4 Type of Structure ", Acta Cryst., (1949), 2, 57).

 The alkaline or alkaline-earth elements can be introduced into these cationic vacancies, until saturation or not of these latter. The presence of this element in the sulphide or sesquisulphide can be evidenced by simple chemical analysis. Moreover, the X-ray diffraction analyzes show that in the case of this variant, there is preservation of the crystalline phase in Th3P4 of the sesquisulphide, with

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 in some cases, a more or less significant modification of the mesh parameters, a function of both the nature and the quantity of the alkaline or alkaline-earth element introduced.

 In the case of sesquisulphide, the rare earth may be more particularly cerium or lanthanum. Even more particularly, the rare earth sesquisulphide is a sesquisulphide Ce2S3 and cubic.

 Generally, the amount of alkaline or alkaline earth element is at most 50% of the rare earth molar amount of sulfide or sesquisulphide.

 According to another characteristic, the molar amount of alkali or alkaline earth is at least 0.1%, and advantageously between 5% and 50% and more particularly 5 and 20%, of the molar amount of rare earth.

 Mention may also be made as rare earth sulfides used as support in the context of the present invention, those described in the European patent application EP-A-680930 to the description of which we can refer. These rare earth sulfides comprise at least one alkaline element and they consist of monocrystalline whole grain grains of average size of at most 1.5 μm. They are obtained by a process in which at least one rare earth carbonate or hydroxycarbonate is brought into contact with at least one compound of an alkaline element and the mixture is heated in the presence of at least one gas chosen from hydrogen or carbon disulfide. These products also have an average size (CILAS particle size) generally less than 2 m, more particularly between 0.7 and 1.5 m. After deagglomeration under mild conditions, the average size may be at most 1.5um and advantageously between 0.3 and 0.8pm.

 According to a particular embodiment of the invention, the support of the composition may further comprise a second layer based on at least one oxide deposited on the surface of the support, the oxide being capable of having OH groups. of surface. In this embodiment, this second layer is thus disposed between the support and the aforementioned layer (first layer) based on the copolymer.

 This second layer coating the support may not be perfectly continuous or homogeneous. However, preferably, this coating layer is uniform and of controlled thickness.

 The oxide must be capable of having OH-surface groups. It is also generally and preferably a transparent oxide. By transparent oxide is meant here an oxide which, once deposited on the support in the form of a film more or less fine, absorbs little or no light at all in the visible range, and this of so as not to mask the original intrinsic color of said support. In addition, it should be noted that the term

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 The oxide, which is used for convenience throughout this specification, should be understood as also covering hydrated type oxides.

 These oxides, or hydrated oxides, can be amorphous and / or crystallized.

 By way of example of such oxides, mention may be made more particularly of silicon oxide (silica), aluminum oxide (alumina), zirconium oxide (zirconia), titanium oxide and silicate. zirconium ZrSiO4 (zircon) and rare earth oxides. According to a preferred variant, the coating layer is based on silica. Even more advantageously, this layer is essentially, and preferably solely, silica. The aforementioned oxides thus have surface groups of the type AI-OH, Ti-OH or Si-OH.

 This second layer may be deposited on the support by a precipitation process for example.

 Reference may also be made to a product of this type comprising such a layer, and its method of preparation, to the European patent application EPA-620254.

 The composition comprises, in addition to the support, a layer at least partially coating it. Again, this layer may not be perfectly continuous or homogeneous. However, preferably, this coating layer is uniform.

 This layer is based on a block copolymer. By this and in the case of the present invention is meant a copolymer which has at least one block or a fluorinated chain. The copolymer furthermore has at least one other block whose characteristic is to be compatible with the application medium of the composition, for example paint. By compatible is meant that the composition which contains the copolymer does not give rise to demixing when it is put into the application medium. The copolymer may be more particularly a diblock type copolymer.

 The block copolymers that may be used in the context of the present invention may be chosen from those corresponding to formulas (1a), (1b), (1c) below: (1a) - [- Am-Bn-] ## EQU1 ##

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et -(-B-)- un bloc de formule :

etoù: - V, V', W et W', identiques ou différents, représentent : H, un groupe alkyle ou un halogène, - X et X' identiques ou différents, représentent H, un halogène ou un groupe R1,
OR', OCOR\ NHCOH, OH, NH2, NHR', N(R')2, (R')2N+O-, NHCOR', C02H,
CO2R1, CN, CONH2, CONHR' ou CONR'2, dans lesquels R1 est choisi parmi les groupes alkyle, aryle, aralkyle, alkaryle, alcène ou organosilyle, éventuellement perfluorés et éventuellement substitués par un ou plusieurs groupes carboxyle, époxy, hydroxyle, alkoxy, amino, halogène ou sulfonique, avec comme condition qu'au moins un de X et X' et/ou R1 est un atome de fluor et/ou au moins un des subtituants de R1 est un atome de fluor; - Y et Y', identiques ou différents, représentent H, un halogène autre que le fluor ou un groupe R2,OR2, OCOR2, NHCOH, OH, NH2, NHR2, N(R2)2, (R2)2N+O-,
NHCOR2, C02H, C02R 2, CN, CONH2, CONHR2ou CONR22, dans lesquels R2 est choisi parmi les groupes alkyle, aryle, aralkyle, alkaryle, alcène ou organosilyle, et éventuellement substitués par un ou plusieurs groupes carboxyle, époxy, hydroxyle, alkoxy, amino, halogène autre que le fluor ou sulfonique, - a et b, identiques ou différents, valent 0 ou 1, - m, m1, m2, n, n1 et n2 identiques ou différents, sont supérieurs ou égaux à 1, et lorsque l'un ou l'autre est supérieur à 1, les motifs unitaires répétitifs sont identiques ou différents ; - 8 est un nombre entier égal ou supérieur à 1. - (-A -) - is a block of formula:

and - (- B -) - a block of formula:

andwherein: V, V ', W and W', which may be identical or different, represent: H, an alkyl group or a halogen, X and X ', which may be identical or different, represent H, a halogen or a group R1,
OR ', OCOR \ NHCOH, OH, NH2, NHR', N (R ') 2, (R') 2N + O-, NHCOR ', CO2H,
CO2R1, CN, CONH2, CONHR 'or CONR'2, in which R1 is chosen from alkyl, aryl, aralkyl, alkaryl, alkene or organosilyl groups, optionally perfluorinated and optionally substituted by one or more carboxyl, epoxy, hydroxyl or alkoxy groups; amino, halogen or sulfonic acid, with the proviso that at least one of X and X 'and / or R 1 is a fluorine atom and / or at least one of R 1 is a fluorine atom; Y and Y ', which may be identical or different, represent H, a halogen other than fluorine or a group R2, OR2, OCOR2, NHCOH, OH, NH2, NHR2, N (R2) 2, (R2) 2N + O-,
NHCOR2, CO2H, CO2R2, CN, CONH2, CONHR2 or CONR22, wherein R2 is selected from alkyl, aryl, aralkyl, alkaryl, alkene or organosilyl groups, and optionally substituted with one or more carboxyl, epoxy, hydroxyl, alkoxy groups, amino, halogen other than fluorine or sulphonic, - a and b, which are identical or different, are 0 or 1, - m, m1, m2, n, n1 and n2, which are identical or different, are greater than or equal to 1, and when one or the other is greater than 1, the unit repetitive units are identical or different; - 8 is an integer equal to or greater than 1.

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peut être plus particulièrement le bloc dans lequel b=0, X' est l'hydrogène et X représente un groupe R1, OR', OCOR', C02R', R1 étant tel que défini plus haut et avec la condition précitée, et pouvant être plus particulièrement un radical alkyl. The fluorinated block - (- B -) -:

may be more particularly the block in which b = 0, X 'is hydrogen and X represents a group R 1, OR', OCOR ', CO 2 R', R 1 being as defined above and with the aforementioned condition, and may be more particularly an alkyl radical.

 According to a particular embodiment, the fluorinated block can be the block in which b = 0, X 'is hydrogen and X is the group -CO-O-R1, R1 being an alkyl radical, X being thus even more especially the group -CO-O- (CH2) 2-CpF2p + 1. In the latter case p is an integer at least equal to 1, more particularly between 1 and 25 and preferably between 5 and 20.

peut être plus particulièrement le bloc dans lequel a=0, Y' est l'hydrogène et Y représente un groupe R2,OR2, OCOR2, C02R2, R2étant tel que défini plus haut et pouvant être plus particulièrement un radical alkyl. The other block - (-A -) - of the copolymer:

may be more particularly the block in which a = 0, Y 'is hydrogen and Y represents a group R2, OR2, OCOR2, CO2R2, R2 being as defined above and may be more particularly an alkyl radical.

 According to a particular embodiment, this other block may be the block in which b = 0, Y 'is hydrogen and Y is the group -O-CO-R2, R2 may be more particularly the CH3 group.

 Terminals R3 and R4 at the ends of the copolymer, R3 - (- fluorinated block - second block) - R4, are not critical in the context of the present invention.

Thus, R3 and R4 can be: an (i) alkyl, acyl, aryl, alken or optionally substituted alkyne group, or a cycle (ii) carbon, saturated or unsaturated, optionally substituted or aromatic, or. a heterocycle (iii), saturated or unsaturated, optionally substituted,
R4 may more particularly be a group -Z1-CS-Z2-R5 wherein: - Z1 = S or P, - Z2 = O, S or P, and R5 has the same definition as R3 and R4.

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According to one variant, R4 may especially represent a xanthate termination of formula (2): -S-CS-O-C2H5
The number (m) of units or fluorinated blocks can be in particular between 2 and 20 and the number of other units or non-fluorinated blocks (n) between 6 and 60.

The copolymers described above having the R3 terminations and a -Z1-CS-Z2-R6 termination as previously indicated, can be prepared by the method described in published patent application WO 98/58974. This process consists essentially of bringing into contact a radical polymerization initiator, a precursor of general formula (3):
R3-Z1-CS-Z2-R5 and a fluorinated ethylenically unsaturated monomer B at first and then with the second monomer A in a second time.

 The radical polymerization initiator may be chosen from the initiators conventionally used in radical polymerization, for example from initiators of the hydrogen peroxide type, azo compounds, redox systems comprising combinations such as mixtures of hydrogen peroxide, alkyl, peresters, percarbonates and the like and any of the iron salts, titanium salts, zinc formaldehyde sulfoxylate or sodium formaldehyde sulfoxylate, and reducing sugars; persulfates, perborate or perchlorate of alkali metals or ammonium in combination with an alkali metal bisulfite; the alkali metal persulfate in combination with an arylphosphinic acid.

 As the ethylenically unsaturated monomer A, the monomers chosen from styrene or its derivatives, butadiene, chloroprene, (meth) acrylic esters, vinyl esters and vinyl nitriles are used more specifically according to the invention.

 As the ethylenically unsaturated monomer B, fluorinated (meth) acrylic esters are used more specifically according to the invention.

 Finally, the precursor compound of general formula (1) must be a polymer, therefore n is greater than or equal to 1, preferably greater than or equal to 6. The monomer units of this polymer may be identical or different.

 With regard to the composition according to the invention, it is possible to think that the copolymer is deposited on the support and all the copolymers deposited or in contact with the support thus constitute the layer coating the support.

 According to a preferred embodiment of the invention, in this layer, the copolymers are predominantly, preferably totally, arranged in such a way that the block other than the fluorinated block is located in the outer part of the layer and the other chain or the other (non-fluorinated) block is located in the inner part of the layer.

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 By this is meant that the fluorinated chain is in contact with the support, in the part of the layer closest to the support, while the non-fluorinated chain is located in the part of the layer furthest from the support and is thus turned towards the outside of the composition. It is this chain that will be in contact with the medium in which the composition will be used.

 Note finally that the amount of copolymer is dependent on the specific surface of the support or the pigment. Sufficient amount of copolymer is used to provide maximum support coverage. In general, for a support having a specific surface area of 3 to 4 m 2 / g, an amount of copolymer of about 1% by weight with respect to the support is used, this amount generally being substantially proportional to the specific surface area.

 The process for preparing the composition of the invention will now be described.

 The method comprises contacting the support with the block copolymer and precipitating the copolymer on the support.

 The precipitation can be carried out as follows. A suspension or solution of the support is formed in a first solvent which is not a solvent of the copolymer. In addition, a solution of the copolymer is prepared in a second solvent which is a good solvent for this copolymer. The suspension or solution of the support is brought into contact with and mixed with the solution of the copolymer. The second solvent is then removed from the medium thus formed. The removal of the second solvent makes it possible to precipitate the copolymer on the support. This removal of the second solvent can be done by distillation.

 When it is desired to obtain a composition according to the preferred embodiment described above, ie a composition in which the unfluorinated chain of the copolymers is disposed in the outer part of the layer and the fluorinated chain is located in the inner part a solvent is used as the first solvent which solubilizes preferentially the non-fluorinated chain with respect to the fluorinated chain.

 At the end of the reaction, the resulting composition is separated from the reaction medium by any suitable means.

 The invention also relates to colored pigments consisting of or comprising at least one composition of the type which has just been described above.

 The compositions or pigments according to the invention have a very good coloring power and a very good hiding power and, therefore, are perfectly suitable for coloring many materials, such as plastics, paints and others.

 Thus, and even more specifically, they can be used in the coloring of plastics which may be of the thermoplastic or thermosetting type.

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 As thermoplastic resins capable of being colored according to the invention, mention may be made, for purely illustrative purposes, of polyvinyl chloride, polyvinyl alcohol, polystyrene, styrene-butadiene, styrene-acrylonitrile and acrylonitrilebutadiene-styrene copolymers (ABS ), acrylic polymers, especially polymethyl methacrylate, polyolefins such as polyethylene, polypropylene, polybutene, polymethylpentene, cellulose derivatives such as, for example, cellulose acetate, cellulose acetate butyrate, ethylcellulose, polyamides including polyamide 6-6.

 As regards the thermosetting resins for which the compositions or pigments according to the invention are also suitable, mention may be made, for example, of phenoplasts, aminoplasts, in particular the urea-formaldehyde copolymers, melamineformol, epoxy resins and thermosetting polyesters.

 The compositions or pigments of the invention can also be used in special polymers such as fluorinated polymers, in particular polytetrafluoroethylene (PTFE), polycarbonates, silicone elastomers and polyimides.

 In this specific application for coloring plastics, the compositions or pigments of the invention can be used directly in the form of powders. They can also preferably be used in a predispersed form, for example by premixing with a part of the resin, in the form of a paste concentrate or a liquid, which makes it possible to introduce them to any what stage of resin manufacture.

 Thus, the compositions or pigments according to the invention can be incorporated into plastics such as those mentioned above in a proportion by weight ranging generally from 0.01 to 5% (referred to the final product) or from 40 to 70% by weight. % in the case of a concentrate.

 The compositions or pigments according to the invention are also likely to be suitable for applications in the rubber industry, in particular in floor coatings, in the paper and printing ink industry, in cosmetic products, in glazes and for many other uses such as, for example, and not limited to laminate coatings, in particular for kitchens and other worktops, ceramics.

 The compositions or pigments of the invention can be particularly used in the field of paints.

 In the present description, the term "paint" is used generically. It denotes any coating of polymeric nature deposited on a substrate and more particularly the actual paints (aqueous paints, solvent paints, powder paints), varnishes, stains and plastic resins. These include paints comprising the following resins: alkyd resins, the most

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 common is called glycerophthalic; resins modified with long or short oil; acrylic resins derived from esters of acrylic acid (methyl or ethyl) and methacrylic acid optionally copolymerized with ethyl acrylate, 2-ethylhexyl or butyl; vinyl resins such as, for example, polyvinyl acetate, polyvinyl chloride, butyralpolyvinyl, formalpolyvinyl, and copolymers of vinyl chloride and vinyl acetate or vinylidene chloride; the aminoplast or phenolic resins most often modified; polyester resins; polyurethane resins; epoxy resins; silicone resins.

 Generally, the compositions or the pigments are used in a proportion of 5 to 60% by weight of the paint and 0.1 to 5% by weight of the glaze.

 The paints are preferably paints used in the household and industrial sector, in particular the building and the car industry. The most common substrates are wood; metals and their alloys such as steel, stainless steel, aluminum, copper, iron; plastics and mineral glasses; cements, plaster and fiber cement.

 The compositions or pigments of the invention are particularly interesting for paints for prepainted sheet metal for stamping (of the so-called "coil-coating" type). These are industrial paints used to paint generally metal panels that will be stamped after application of the paint. Industrially, these paints are applied in a continuous process by spraying, drying and then firing at high temperature for very short periods of time. This kind of paint is therefore requested for good flexibility as well as good adhesion, folding tests are carried out for this purpose. These paints must also crosslink very quickly, so systems with catalyst are used.

 These paints must also have good external resistance and the dispersion of the pigments must be optimized. Indeed the deposited paint thicknesses can be very low, of the order of about ten microns for example.

 The invention thus relates to paints, especially of the above type, comprising a composition or a pigment as described above.

 Examples will now be given.

EXAMPLE 1
This example relates to the preparation of compositions or pigments according to the invention.

 Starting from a rare earth sesquisulphide pigment of the type described in particular in Example 2 of the European patent application EP-A-620254. It is a cerium sesquisulphide Ce2S3 doped with sodium in a molar ratio Na / Ce of

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 0.2 and coated with a silica layer in a mass ratio SiO2 / Ce2S3 of 4.6%. This product is comparative product 1.

 Furthermore, a suspension of the product 1 in xylene at 55% solids is prepared using a disperser equipped with a deflocculating blade at 900 rpm. Milling is carried out for 20 minutes at 4000 rpm. A 1% solution of fluorinated di-block copolymers in trifluoro-trichloroethane is incorporated in this suspension so as to have a level of 1% diblocks with respect to the pigment. Then the fluorinated solvent is removed by distillation using a Vigreux column (the boiler having a temperature of about 75 C and the column head a temperature of 48 C (Téb CCI3-CF3)).

p variant de 6 à 18. Two copolymers of formula (4) are used for the products according to the invention:

p varying from 6 to 18.

 These copolymers of formula (4) both additionally have a xanthate terminus according to formula (2).

 By using a copolymer of formula (4) in which m = 10 and n = 30, a product 2 according to the invention is obtained and using a copolymer of formula (4) in which m = 2 and n = 6 gives a product 3 according to the invention.

 To verify that the copolymer has been deposited on the surface, a wetting test is carried out in the water of the dried product (measurement of compatibility of the product in polar solvents) and a measurement of the contact angle of a drop of water on the dried product.

 Table 1 below gives the results obtained.

Table 1

<Tb>
<tb> Product <SEP> angle <SEP> of <SEP> test <SEP> of <SEP> wetting <SEP> in <SEP> water
<tb> wetting <SEP> with
<tb> water
<tb> 1 <SEP> comparative <SEP> 0 <SEP> mooring
<tb> 2 <SEP> 139 <SEP> Flotation
<tb> - ~~ <SEP> ~~~~ <SEP> 3 <SEP> ~~ <SEP> ~ <SEP> ~ <SEP> 127 <SEP> Flotation
<Tb>

The treated products have a hydrophobic behavior; they are no longer dispersed in water and the contact angles with water are greater than 90.

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EXAMPLE 2
This example shows the properties of the products of the invention in their application in painting and in a formulation of the polyester-melamine type prepared as indicated below.

Preparation of the grinding base:
The grinding base is prepared from the following constituents:
URALAC SN800 (polyester resin) 31.64 g
CYMEL 303 (melamine crosslinking agent) 20.87 g
BYK 354 (spreading agent) 2.77 g
SOLVESSO 150 (75%) DOWANOL PNB (25%) (solvents) 16.98 g pigment 27.74 g
120 g of glass beads of one millimeter in diameter are added.

 The mixture is ground using a disperser equipped with a Teflon disk for 20 minutes at 7000 rpm. After grinding, the crushed material is recovered by filtering on a 100 micron fabric.

Preparation of the painting:
The paint is prepared from the grinding base obtained previously with the following constituents: grinding base 54.08 g
URALAC SN800 (polyester resin) 89.06 g
SOLVESS0150 (75%) DOWANOL PNB (25%) (solvents) 6.51 g
CYCAT 4040 (paratoluene sulfonic acid catalyst PTSA) 1 g
Drying conditions:
The tests include an air drying phase of one hour (time required for the evaporation of solvents). The crosslinking conditions are a temperature of 140 ° C. and a duration of twenty minutes. For the tests of evaluation of the thermal resistance, a sweep in temperature was carried out of 200 C to 300 C for times of 2 minutes.

 The various properties obtained for the paint comprising products according to the invention or according to the prior art are given below.

colorimetry
Measurement conditions:
The colorimetric measurements are carried out according to the ISO 7724 standard using a DATACOLOR DC3890 spectrocolorimeter.

 The measurement conditions are as follows:

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- specular excluded (only backscattered intensity is measured) - ultraviolet is 100% filtered - the results are expressed under the illuminant / observer torque C / 10
The measurements were made on contrast cards, the paint being applied at 150 microns wet. The results are given in Table 2 below.

Table 2

<Tb>
<tb> 30 'DRYING <SEP> AIR. <SEP> 20 '<SEP> 140 C
<tb> COLORIMETRY <SEP> LENETA <SEP> BOTTOM <SEP> WHITE <SEP> BOTTOM <SEP> BLACK
<tb> Product <SEP> L * <SEP> a * <SEP> b * <SEP> L * <SEP> a * <SEP> b *
<tb> 1 <SEP> comparative <SEP> 42.97 <SEP> 56.41 <SEP> 58.01 <SEP> 38.59 <SE> 47.83 <SEP> 51.38
<tb> 2 <SEP> 42.99 <SEP> 56.18 <SEP> 57.25 <SEP> 37.47 <SEP> 45.62 <SEP> 48.99
<tb> 3 <SEP> 42.87 <SEP> 56.39 <SEP> 57.55 <SEP> 38.15 <SEP> 47.08 <SEP> 50.25
<Tb>

Opacity
The evaluation of the opacity is performed as follows:
The paint to be tested is applied to polyester films at 50,100 and 150 microns wet. For each film, the deposited dry thickness is measured (using a thickness gauge (Fisher)), the color on a white background and the color on a black background. Then for each thickness, we calculate the difference in hue (dE *) between the white background and the black background. The curve of the color difference is plotted against the thickness for each paint. Finally, for each paint, the difference in hue is extrapolated to an identical thickness for each sample. The results are given in Table 3 below.

Table 3

<Tb>
<tb> 30 'DRYING <SEP> AIR, <SEP>20'<SEP> 140 C
<tb> OPACITY <SEP> PET
<tb> Product <SEP> dE * <SEP> to <SEP> 40 m
<tb> 1 <SEP> comparative <SEP> 7.6
<tb> 2 <SEP> 7.2
<tb> 3 <SEP> 6.8
<Tb>
The products of the invention, and most particularly the product 3, substantially improve the opacity.

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rheology
The rheology of the paints was evaluated using the CARRIMED CSL 100 rotary rheometer by performing a speed gradient sweep from 0 to 100 s-1 and then a step at 100 s-1 and a speed gradient descent from 100 to 0 s-1. . These measurements make it possible to evaluate the rheological behavior of the paint and to apprehend the dispersing effect of the additives grafted on the surface of the pigments. The quality of the dispersion is evaluated using two parameters: the viscosity at 100 s-1 and the rheological behavior of the paint (Newtonian or Rheofluidifier). The results are given in Table 4 below.

<Tb>
<Tb>

Table <SEP> 4
<tb> Product <SEP> Behavior <SEP> Viscosity <SEP> to <SEP> 100 <SEP> s-1 <SEP> (Pa.s)
<tb> 1 <SEP> comparative <SEP> newtonian <SEP> 3.8
<tb> 2 <SEP> newtonian <SEP> 2
<tb> 3 <SEP> newtonian <SEP> 2,2
<Tb>

It is found by these measures that the paints comprising a product according to the invention have a better dispersion; the viscosity of these paints is lower than that comprising an untreated product. The products of the invention therefore offer greater ease and greater flexibility of use in the application environment than those of the prior art.

Mechanical strength
Various tests have been implemented to evaluate the flexibility and adhesion of the paint films. The adhesion is evaluated by a grid test (standard ISO 2409): the cutter is made a grid of 100 tiles of one millimeter side; an adhesive tape is applied to the grid; remove the tape and evaluate the condition of the grid with a score ranging from 0 (no peeling paint) to 5 (the paint is completely peeled).

 The flexibility of the paint film is tested using the following tests: - the ERICHSEN stamp test (ISO 1520 standard): a steel ball is applied to a stress and a constant speed on the back of the plate To test, this ball deforms the plate, we note the distance of penetration of the ball at which the paint begins to crack.

 the deformation test using a cylindro-conical mandrel: the paint plate to be tested is deformed on a cylindro-conical mandrel; we note the radius of curvature of the mandrel to which the paint begins to crack.

 The results are given in Tables 5 and 6 below.

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Table 5
Adhesion results 30 'AIR DRYING, 20' 140 C PLATE AL36

<Tb>
<tb> Product <SEP> Adherence
<tb> 1 <SEP> comparative <SEP> 0
<tb> 2 <SEP> 0
<tb> 3 <SEP> @ <SEP> 0
<Tb>

Table 6
Flexible results 30 'AIR DRYING. 20 '140 C PLATE AL36

<Tb>
<tb> Product <SEP> Stamps <SEP> Erichsen <SEP> Chuck <SEP> Cylindrical Cone
<tb> v = 5.8mm / min
<tb> 1 <SEP> comparative <SEP> 6.1 <SEP> *
<tb> 2 <SEP> 6.4 <SEP> *
<tb> 3 <SEP> 6.5
<Tb>
In all cases, no cracking of the paint was observed using the smallest radius of curvature of the mandrel.

 The presence of copolymers deposited on the products of the invention does not alter the flexibility of the paint film or its adhesion. It can therefore be expected that the deposited copolymers remained well on the surface of the pigment and that there was no migration to the interfaces of the film, otherwise the values given above would be bad.

Resistance to acids:
The resistance to acids is evaluated on dry paint
A drop of 90% sulfuric acid is deposited in the water on the paint film to be tested. The color variations are measured every minute using a colorimeter equipped with automatic measurement acquisition and under the measurement conditions given above in the paragraph colorimetry. The results are expressed by giving the speed

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 the color varies (dE * / min). The results are given in Table 7 which follows.

Table 7

<Tb>
<tb> Product <SEP> dE * / min
<tb> 1 <SEP> comparative <SEP> 0.37
<tb> 2 <SEP> 0.29
<tb> 3 <SEP> @ <SEP> 0.28
<Tb>

The products according to the invention have a pronounced protective effect.

Thermal resistance of paints
Coil-coating paints have relatively high cooking temperatures.

It is therefore necessary to evaluate the thermal resistance of the pigments. Indeed, under the action of heat, the pigment can oxidize and pass from the sulfide form to the rare earth sulfate form. For this, the paints are crosslinked at different temperatures (from 200 to 280 ° C.) for a period of two minutes. The gloss is measured for each painting. The cross-linked samples at 200 ° C. will be used as reference.

The results of brightness monitoring are given in Table 8 which follows and in which is indicated the variation of brightness between 200 C and 280 C
Table 8

<Tb>
<tb> PLATE <SEP> AL36, <SEP> HELD <SEP> THERMAL <SEP> DRY <SEP> AIR <SEP> 30 ', <SEP>2'<SEP>
<tb> OVEN <SEP> FOLLOW-UP <SEP> BRILLIANCE <SEP> 20
<tb> Product <SEP>#
<tb> 1 <SEP> comparative <SEP> 22%
<tb> 211%
<tb> 314%
<Tb>

In terms of brightness variation, there is a clear improvement for paints incorporating the products of the invention.

EXAMPLE 3
This example describes an application of a pigment of the invention in a plastic.

 Rotary cube is mixed with polyamide 12 granules (Rilsan AMN D natural from Atochem company not protected against UV) with the pigment (1% by weight) (either the comparative product 1 or the product 3) and an agent ". fixative butyl stearate (0.05%).

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The mixture was extruded on a 30 mm diameter twin-screw extruder (ZSK 30 from Werner & Pfleiderer) and then injection molded on Arburg 35T press (350-90 220D allrounder) at 220 ° C to obtain platelets 48 x 40 x 4 mm. These pads are subjected to a XENOTEST accelerated aging test (ISO 4892) under the following conditions:
Irradiation conditions: xenon arc lamp with suprax filters simulating solar lighting approximately one hundred times more intense, the irradiance is regulated at 65 W / m2
Chamber temperature: 30 C Operating cycle: 27 minutes of irradiation in the dry phase at t = 30 C then 3 minutes of wet irradiation at t = 30 C. The moisture supply is done by spraying directly from liquid water on the test plates by means of nozzles.

The difference in hue (dE *) is measured after 2500 hours. The results given in Table 9 below are obtained:
Table 9

<Tb>
<tb> Product <SEP> dE *
<tb> 1 <SEP> comparative <SEP> 2,3
<tb> 3 <SEP> 0.5
<Tb>

The pigment of the invention clearly improves the aging resistance of the plastic.

EXAMPLE 4
This example relates to a composition according to the invention in which the support pigment is titanium oxide.

 For the preparation of the product, the procedure is as in Example 1 by preparing a suspension of TiO 2 in xylene. The titanium oxide used is the RCL 535 product from the Millennium Company which has a surface layer of alumina. In addition, a copolymer of formula (4) in which m = 10 and n = 30 is used. The product obtained constitutes the product 4. The amount of copolymer present in the product is 0.5% by weight relative to the titanium oxide. For comparison, the pigment based on TiO 2 without copolymer constitutes the product 5.

 Products 4 and 5 are used in an isocyanate acrylic paint prepared as shown below.

Preparation of the grinding base:
PMA (Methoxy 2, propyl acetate) 4.5 g
Butyl acetate 4.5 g
MULTIFLOW (spreading agent) 0.15 g

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MACRYNAL SM51 ON (acrylic polyol) 19.95 g
Ti02 (pigment) 30gr
90 gr of glass beads of one millimeter in diameter are added.

 The mixture is milled at pendraulyk equipped with a Teflon disc for 20 minutes at 7000 rpm. The crushed material is recovered by filtering on a 100 micron fabric.

Preparation of the painting:
GRINDING BASE 23,23 gr
MACRYNAL SM51 ON 70 gr
Hardener addition before application of the paint: tolonate HDB 75 MX (isocyanate) at 15% by weight
Cooking conditions:
Drying in ambient air for 1 h and then cooking in a ventilated oven for 30 'at 100 C.

 The results concerning brightness and opacity are given in Table 10 below, the measurements being made according to the methods described in Example 2.

Table 10

<Tb>
<tb> Product <SEP> Gloss <SEP> 20 <SEP> dE * <SEP> to <SEP> 40 m
<tb> 4 <SEP> 84 <SEP> 4.3
<tb> 5 <SEP> comparative <SEP> 82 <SEP> 8.3
<Tb>

The product of the invention and that of the prior art have similar glosses. On the other hand, the opacity is very much improved by the product of the invention.

EXAMPLE 5
This example relates to a composition according to the invention in which the support pigment is an organic pigment Naphtol type AS (Red Novaperm F3RK70 Hoechst).

 For the preparation of the product, the procedure is as in Example 1 by preparing a suspension of the organic pigment in xylene. In addition, a copolymer of formula (4) in which m = 10 and n = 30 is used. The product obtained constitutes the product 6. For comparison, the pigment based on the untreated organic pigment constitutes the product 7.

 These two products are used in the paint described in Example 2.

 The thermal resistance of the paint is then determined under the same conditions as those given in Example 2 by measuring the variation in color AE between 140 ° C. and 230 ° C.

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The results are shown in Table 11 below.

Table 11
PLATE AL36. THERMAL DRY AIR DRYING 30 ', 2'

<Tb>
<tb> OVEN, <SEP> FOLLOW-UP <SEP> DIFFERENCE <SEP> FROM <SEP> TINT
<tb> Product <SEP>#E
<tb> 6 <SEP> 0.57
<tb> 7 <SEP> comparative <SEP> 7,31
<Tb>

In conclusion, it appears from the properties given above that the treatment of the invention leads to pigments on which the copolymers are well fixed or deposited.

 It is noted that the thermal resistance of the organic pigments is particularly improved. Thus, as seen from Example 5, a pigment is obtained which is stable at a temperature of 230 ° C.

 In addition, the copolymers do not desorb during the formulation and during the drying of the paints. There is no migration of the copolymers to the interfaces of the paint film. This point is essential for the adhesion of the paint with its support and the other layers of varnish or paint that can be applied. Indeed, in industrial applications of paint, it is not uncommon for metal parts to be painted with several layers of paint (adhesion primer, primer and varnish). On the contrary, the usual additives or surfactants used to disperse the pigment partially desorb and alter the adhesion of the paint.

 The deposition of the copolymers has a dual role. It offers a barrier to water and oxygen and a compatibilizing effect with the paint which improves the dispersion of these pigments.

Claims (22)

CLAIMS 1- Composition characterized in that it comprises: - a support based on a pigment; a layer at least partly coating said support and based on a block copolymer comprising at least one fluorinated block. 2- Composition according to claim 1, characterized in that the pigment is an inorganic pigment chosen in particular from silico-aluminates and titanium oxide. 3. Composition according to claim 1, characterized in that the pigment is a rare earth sulphide, more particularly a rare earth sulphide which contains at least one alkaline and / or alkaline earth element of which at least part is included in the composition. crystal lattice of said sulfide. 4. Composition according to claim 3, characterized in that the rare earth sulphide consists of whole monocrystalline grains of average size of not more than 1.5 m. Composition according to claim 3 or 4, characterized in that the sulphide of rare earth is a sesquisulphide. 6. Composition according to one of claims 3 to 5, characterized in that the amount of alkaline element and / or alkaline earth is at most 50% of the molar amount of rare earth and in that it is in particular between 5 and 50% of this quantity. 7- Composition according to one of claims 3 to 6, characterized in that the sulfide has a crystallographic structure of the Th3P4 type. 8- Composition according to one of claims 3 to 7, characterized in that the alkaline element is lithium, sodium or potassium. 9- Composition according to one of claims 3 to 8, characterized in that the sulphide is cerium sesquisulphide Ce2S3 y cubic. 10- Composition according to one of the preceding claims, characterized in that the support further comprises a second layer, disposed between the support and the <Desc / Clms Page number 21>  first layer based on the abovementioned copolymer, this second layer being based on at least one oxide capable of having surface OH groups. 11- Composition according to claim 10, characterized in that the aforementioned oxide is selected from silica, alumina, zirconia, titanium oxide, zircon and rare earth oxides. 12- Composition according to one of the preceding claims, characterized in that the block copolymer further has at least one other block compatible with the application medium of the composition 13- Composition according to one of the preceding claims, characterized in the block copolymer is selected from those of formulas (1a), (1b), (1c) below:

 in which: - (-A -) - is a block of formula:

 and - (- B -) - a block of formula:

 and wherein: V, V ', W and W', which may be identical or different, represent: H, an alkyl group or a halogen, <Desc / Clms Page number 22>  X and X ', which are identical or different, represent H, a halogen or a group R1, OR ', OCOR', NHCOH, OH, NH2, NHR ', N (R') 2, (R ') 2N + O-, NHCOR', CO2H, CO2R1, CN, CONH2, CONHR 'or CONR12, wherein R1 is selected from alkyl, aryl, aralkyl, alkaryl, alkene or organosilyl groups, optionally perfluorinated and optionally substituted by one or more carboxyl, epoxy, hydroxyl, alkoxy, amino groups; , halogen or sulphonic acid, with the proviso that at least one of X and X 'and / or R1 is a fluorine atom and / or at least one of the substituents of R1 is a fluorine atom, Y and Y ', which may be identical or different, represent H, a halogen other than fluorine or a group R2, OR2, OCOR2, NHCOH, OH, NH2, NHR2, N (R2) 2, (R2) 2N + O-, NHCOR2, CO2H, CO2R2, CN, CONH2, CONHR2 or CONR22, wherein R2 is selected from alkyl, aryl, aralkyl, alkaryl, alkene or organosilyl groups, and optionally substituted with one or more carboxyl, epoxy, hydroxyl, alkoxy groups; , amino, halogen other than fluorine or sulfonic, - a and b, identical or different, are 0 or 1, - m, m1, m2, n, n1 and n2 identical or different, are greater than or equal to 1, and when one or the other is greater than 1, the unit repetitive units are identical or different; - # is an integer equal to or greater than 1. 14. Composition according to claim 13, characterized in that the fluorinated block:

 is the block in which b = 0, X 'is hydrogen and X represents a group R1, OR', OCOR ', CO2R1, R1 being as defined above and with the aforementioned condition, and which can be more particularly a radical alkyl. 15- The composition according to claim 14, characterized in that the fluorinated block is the block in which b = 0, X 'is hydrogen and X is the group -CO-O-R1, R1 being an alkyl radical, X being thus still more particularly the group -CO-O- (CH2) 2-CpF2p + 1 where p is an integer at least equal to 1, more particularly between 1 and 25. 16- Composition according to one of claims 13 to 15, characterized in that the block of the copolymer: <Desc / Clms Page number 23>

 is the block in which a = 0, Y 'is hydrogen and Y represents a group R2, OR2, OCOR2, CO2R2, R2 being as defined above and being more particularly an alkyl radical. 17- Composition according to one of the preceding claims, characterized in that the block copolymer has a number of units or fluorinated blocks B between 2 and 20 and a number of other units or non-fluorinated blocks A between 6 and 60 . 18- Composition according to one of the preceding claims, characterized in that in the layer coating the support, the block copolymer is predominantly arranged so that the fluoride block is located in the outer part of the layer and the other block is located in the inner part of the layer. 19- A method for preparing a composition according to one of the preceding claims, characterized in that the contact is placed in contact with the block copolymer and the copolymer is precipitated on the support. 20. A process according to claim 19, characterized in that a solution or a suspension of the support is brought into contact in a first solvent, which is not a solvent of the block copolymer, with a solution of the block copolymer in a mixture. second solvent, then the second solvent is removed whereby the block copolymer is precipitated on the support. 21. The process as claimed in claim 20, wherein a solvent is used as the first solvent which preferably solubilizes the non-fluorinated chain of the copolymer with respect to the fluorinated chain. 22- colored pigment, characterized in that it is constituted by, or in that it comprises at least one composition according to one of claims 1 to 18. 23. Compositions of colored material, in particular of plastics, rubbers, ceramics, glazes, papers, inks, cosmetics, dyes and laminates, characterized in that they comprise a colored composition or pigment as defined in any one of the following: Claims 1 to 18 and 22. <Desc / Clms Page number 24>  Paint, characterized in that it comprises a composition or a colored pigment as defined in any one of claims 1 to 18 and 22. 25. The paint according to claim 19, characterized in that it comprises at least one resin of the acrylic or polyester type.