WO2001062857A1

WO2001062857A1 - Composition based on a pigment support with a surface block copolymer, use thereof as coloured pigment particularly in paints

Info

Publication number: WO2001062857A1
Application number: PCT/FR2001/000423
Authority: WO
Inventors: Michel Dorget; Jean-Christophe Castaing; Jean-Noël BOUSSEAU; Marie-Pierre Labeau
Original assignee: Rhodia Terres Rares
Priority date: 2000-02-22
Filing date: 2001-02-14
Publication date: 2001-08-30
Also published as: FR2805274A1; AU3567001A

Abstract

The invention concerns a composition based on a pigment support comprising a surface block copolymer, its preparation method and its use as coloured pigment particularly in paints. Said composition is characterised in that it comprises a support based on a pigment and a layer coating at least part of said support and based on a block copolymer including at least a fluorinated block. Said composition is prepared by a method which consists in contacting the support and the block copolymer and in precipitating the copolymer on the support.

Description

COMPOSITION BASED ON A PIGMENTARY SUPPORT HAVING

A SURFACE BLOCK COPOLYMER, ITS USE AS

COLORED PIGMENT, ESPECIALLY IN PAINTS

RHODIA CHEMISTRY

The present invention relates to a composition based on a pigmentary support having a block copolymer on the surface, its preparation process and its use as a colored pigment in particular in paints. Inorganic or organic coloring pigments are widely used in many industries in particular. in those of paints, plastics and ceramics However, it always seems important to further improve their properties such as thermal resistance, durability, measured by resistance to acids or resistance to ultraviolet rays. Furthermore, there is also a need in pigments capable of being able to be used in paints The pigments known for paints generally undergo treatments fixing organic products of the hydrophobic type on their surface, but these products tend to dissolve in the paint and to migrate at the interfaces of the film or paint film when this it is dried which can cause this film to peel off The object of the invention is therefore to develop compositions of the pigment type suitable for use in paint

Another object of the invention is to provide pigment compositions which have good properties with regard to thermal 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 coating at least partially said support and based on a block copolymer comprising at least one fluorinated block The invention also relates to a process for the preparation of such a composition which is characterized in that contacting the support and the block copolymer and the copolymer is precipitated on the support

Other characteristics, details and advantages of the invention will appear even more completely on reading the description which follows, as well as various concrete but nonlimiting 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 particle size of at most 100 μm Preferably this particle size is of at most 5 μm and even more preferably of at most 2 μm

By way of example, there may be mentioned as pigments those of the anthraqumone dioxazine type flaranthrone, idanthrone, quinacridone, phthalocyamine with optionally halogenated copper, isoindohnone, azomethine, perylene, arylamide, diarylide, azo dyes, dmitraniline, naphthol, toiuidine, iron complex , lead chromates, chromium, cobalt, nickel complexes, amino complexes of copper, nickel and cobalt iron compounds such as oxides, titanium compounds such as nickel titanates, and carbon blacks also mention the inorganic pigments chosen from silico-aluminates, calcium carbonate and titanium oxide

As inorganic pigment, it is possible to use in the context of the present invention the rare earth sulphides, in particular those of sesquisulphide structure Ln ₂ S ₃ Ln denoting one or more rare earths. By rare earth is understood the elements of the group constituted by yttnum and the elements of the periodic classification with atomic number inclusive between 57 and 71 Reference may be made in particular to this subject to patent application EP-203838 for this type of sulphides

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

We can refer to this subject to the teaching of European patent application EP-A-545746 It may be recalled that the alkaline element can be chosen in particular from lithium, sodium or potassium Of course, the sulphide can comprise several alkaline or alkaline earth elements According to a variant, the alkaline or alkaline earth element is included essentially or totally in the crystal lattice

The sulfide may more particularly be a sesquisulfide The sesquisulfide may in particular have a cubic cπstailographic structure of the type

which has gaps in the cation network, this lacunar structure can be symbolized by giving sesquisulfides the formula 10.66 [Il 33 ^s 16 ( ^{see in} particular on this subject, WH ZACHARIASEN "Crystai Chemical Studies of the 5f-Seπes of Elements The Ce2S3-Ce3S4 Type of Structure "Acta Cryst, (1949), 2, 57)

The alkaline or alkaline earth elements can be introduced into these cationic vacancies, until the latter is saturated or not. The presence of this element within the sulphide or sesquisulphide can be demonstrated by simple chemical analysis. X-ray diffraction show that in the case of this variant, there is conservation of the crystalline phase in Th3P4 of the sesquisulfide, with in some cases, a more or less significant modification of the mesh parameters, a function both of the nature and of the quantity of the alkaline or alkaline earth element introduced

In the case of sesquisulfide, the rare earth may be more particularly the céπum or the lanthanum. More particularly, the rare earth sesquisulfide is a cubic ses2 sulfide γ2

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

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

Mention may also be made, as rare earth sulfides which can be used as a support in the context of the present invention, of those described in European patent application EP-A-680 930 to the description of which reference may be made. These rare earth sulfides comprise at least an alkaline element and they consist of whole monocrystalline grains of average size of at most 1.5 μm. They are obtained by a process in which at least one carbonate or a rare earth 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 sulfide or carbon sulfide These products also have an average size

(CILAS particle size) generally less than 2 μm, more particularly between 0.7 and 1.5 μm After deagglomeration under mild conditions, the average size can be at most 1.5 μm and advantageously between 0.3 and 0 , 8μm

According to a particular embodiment of the invention, the support of the composition may also 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 surface In this embodiment, this second layer is therefore placed 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 layer coating is uniform and of controlled thickness

The oxide must be capable of having surface -OH groups. It is also generally and preferably a transparent oxide. By transparent oxide, HERE is understood an oxide which, once deposited on the support in the form of 'a more or less fine film, absorbs little or no light rays in the visible range, and this so as to not or little mask the original intrinsic color of said support In addition, it is advisable to note that the term oxide, which is used for convenience throughout this description, should be understood as also covering hydrated type oxides

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

As an example of such oxides, mention may more particularly be made of silicon oxide (silica), aluminum oxide (alumina), zirconium oxide (zirconia), titanium oxide, silicate ZrSιθ4 zirconium (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 only, made of silica The aforementioned oxides thus have surface groups of the Al— OH, Ti— OH or Si— OH type

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

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

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

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

The block copolymers which can be used in the context of the present invention can be chosen from those corresponding to the formulas (1 a), (1 b), (1 c) below

(1 a) - [- A _m - B _n -] Θ—

(1 b) - [- A _m1 - B _n - A _m2 - I—

(1 c) - [- B _n1 - A _m - B _n2 -] _θ -

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

Y - [- C— (- CW = CW—) _a - CH ₂ -] -

I

Y 'and - (- B -) - a block of formula

- [- C— (- CV = CV—) „- CH ₂ -] -

I

X '

and or

- V, V, W and W, identical or different, represent H an alkyl group or a halogen,

- X and X ', identical or different, represent H, a halogen or a group R ¹ , OR ¹ , OCOR ¹ , NHCOH, OH, NH ₂ , NHR ¹ , N (R ¹ ) ₂ , (R ¹ ) ₂ N ⁺ O-, NHCOR ¹ , CO ₂ H,

CO ₂ R ¹ , CN, CONH ₂ , CONHR ¹ or CONR ¹ ₂ , in which R ¹ is chosen from alkyl, aryl, aralkyl, alkaryl, alkene or organosilyl groups, optionally perfluorinated and optionally substituted by one or more carboxyl groups, epoxy, hydroxyl, alkoxy, ammo, halogen or sulfonic, with the condition that at least one of X and X 'and / or R ¹ is a fluorine atom and / or at least one of the R ¹ substituents is an atom of fluorine,

- Y and Y ', identical or different, represent H, a halogen other than fluorine or a group R ² , OR ² , OCOR ² , NHCOH, OH, NH ₂ , NHR ² , N (R) ₂ , (R ² ) ₂ N ⁺ O ^" , NHCOR ² , CO ₂ H, CO ₂ R ² , CN, CONH ₂ , CONHR ² or CONR ² ₂ , in which R ² is chosen from alkyl, aryl, aralkyl, alkaryl, alkene or organosilyl, and optionally substituted by one or more carboxyl, epoxy, hydroxyl, alkoxy, ammo, halogen groups other than fluorine or sulfonic,

- a and b, identical or different, are worth 0 or 1,

- m, m1, m2, n, ni 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 repeating unitary patterns are identical or different,

- θ is an integer equal to or greater than 1 The fluorinated block - (- B -) -

X I

- [- C— (- CV = CV—) _b - CH ₂ -] -

X '

may more particularly be the block in which b = 0, X ′ is hydrogen and X represents a group R ¹ , OR ¹ , OCOR ¹ , CO ₂ R ¹ , R ¹ being as defined above and with the aforementioned condition , and which can more particularly be 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 - R ¹ , R ¹ being an alkyl radical, X possibly thus being also more particularly the group - CO - O - (CH ₂ ) ₂ - C _p F _{2p +} ι 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 The other block - (- A -) - of the copolymer

Y

I

- [- C— (- CW≈CW—) _a - CHa—] - IY 'can be more particularly the block in which a = 0 Y' is hydrogen and Y represents a group R ² , OR ² , OCOR ² , CO ₂ R ² R ² being as defined above and possibly more particularly an alkyl radical

According to a particular embodiment, this other block can be the block in which b = 0, Y ′ is hydrogen and Y is the group - O - CO - R ² , R ² possibly being more particularly the group CH ₃

The terminations R ³ and R ⁴ at the ends of the copolymer, R ³ - (- fluorinated block - second block-) β -R ⁴ are not critical in the context of the present invention Thus R ³ and R ⁴ may be a group ( i) optionally substituted alkyl, acyl, aryl, alkene or alkyne, or a carbon ring (il), saturated or unsaturated, optionally substituted or aromatic, or a heterocycle (m), saturated or unsaturated, optionally substituted, R ⁴ may be more particularly another group - Z - CS - Z ² - R ⁵ in which

- Z ¹ = S or P, - Z ² = O, S or P, and R ⁵ meets the same definition as R ³ and R ⁴ According to a variant, R ⁴ may in particular represent a xanthate termination of formula (2)

- S— CS— O— C ₂ H ₅

The number (m) of fluorinated units or blocks can in particular be between 2 and 20 and the number of other non-fluorinated units or blocks (n) between 6 and 60

The copolymers described above having the terminations R ³ and a termination - Z - CS - Z - R ⁵ as indicated above can be prepared by the process described in the published patent application WO 98/58974 This process essentially consists in contacting a radical polymerization initiator, a precursor of general formula (3)

R ³ - Z ¹ - CS— Z ² - R ⁵

and an ethylenically unsaturated fluorinated monomer B firstly then with the second monomer A secondly

The radical polymerization initiator can 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 alkyl hydrogen peroxide , peresters, percarbonates and the like and any of the iron salts, titanous salts, zinc formaldehyde sulfoxylate or sodium formaldehyde sulfoxylate, and reducing sugars, persulfates, perborate or perchlorate of alkali metals or ammonium association with an alkali metal bisulfite, the alkali metal persulfate in association with an arylphosphinic acid. As ethylenically unsaturated monomer A, the monomers chosen from styrene or its derivatives, butadiene, chloroprene, esters are used more specifically according to the invention. (meth) acrylics, vinyl esters and vinyl nitrites s

As 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 consequently n is greater than or equal to 1, preferably greater than or equal to 6 The monomer units of this polymer can be the same or different

With regard to the composition according to the invention, it may be thought that the copolymer is deposited on the support and all of the copolymers deposited or in contact with the support thus constitutes the layer coating the support

According to a preferred embodiment of the invention in this layer, the copolymers are mainly, preferably totally, arranged in such a way that the block other than the fluorinated block is located in the external part of the layer and the other chain or l other block (not fluorinated) is located in the inner part of the layer 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 therefore rotated towards the outside of the composition It is this chain which will be in contact with the medium in which the composition will be used

Finally, it should be noted that the amount of copolymer is dependent on the specific surface of the support or of the pigment. A sufficient amount of copolymer is used to have maximum coverage of the support. In general, for a support having a specific surface of 3 to 4 m ² / g, a quantity of copolymer of approximately 1% by weight relative to the support is used, this quantity being generally substantially proportional to the specific surface

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

The method consists in bringing the support into contact with the block copolymer and in precipitating this copolymer on the support

The precipitation can be carried out in the following manner. A suspension or a solution of the support is formed in a first solvent which is not a solvent for the copolymer. A solution of the copolymer in a second solvent which is a good solvent for this is also prepared. copolymer The suspension or solution of the support is brought into contact and mixed with the solution of the copolymer The second solvent is then eliminated from the medium thus formed The elimination of the second solvent makes it possible to precipitate the copolymer on the support This elimination of the second solvent can by distillation

When it is desired to obtain a composition according to the preferred mode described above, that is to say a composition in which the non-fluorinated chain of the copolymers is arranged in the external part of the layer and the fluorinated chain is located in the internal part , the first solvent used is a solvent which preferentially solubilizes the non-fluorinated chain with respect to the fluorinated chain

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

The invention also relates to colored pigments constituted by 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 covering power and, therefore, are perfectly suitable for coloring many materials, such as plastics, paints and the like.

Thus and even more precisely, they can be used in the coloring of plastics which can be of the thermoplastic or thermosetting type. As thermoplastic resins capable of being colored according to the invention, mention may be made, purely by way of illustration, of polyvinyl chloride, polyvinyl alcohol, polystyrene, styrene-butadiene, styrene-acrylonitrile, acrylonitrile-butadiene-styrene copolymers. (ABS), acrylic polymers, in particular polymethyl methacrylate, polyolefins such as polyethylene, polypropylene, polybutene, polymethylpentene, cellulose derivatives such as, for example, cellulose acetate, cellulose aceto-butyrate, ethylcellulose, polyamides including polyamide 6-6

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

The compositions or pigments of the invention can also be used in special polymers such as fluoropolymers, in particular polytetrafluorethylene (P T F E), polycarbonates, silicone elastomers, polyimides

In this specific application for coloring plastics, the compositions or pigments of the invention can be used directly in the form of powders. It is also preferably possible to use them in a predispersed form, for example in premix with part of the resin, in the form of a paste concentrate or a liquid which allows them to be introduced at any stage of the resin's manufacture

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

The compositions or pigments according to the invention are also capable of being suitable for applications in the rubber industry, in particular in floor coverings, in the paper and printing ink industry, in cosmetic products, in glazes as well as for many other uses such as for example, and without limitation, laminate coatings, in particular for kitchens and other worktops, ceramics.

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

In the present description, the term "paint" is used in a generic manner. It designates any coating of a polymeric nature deposited on a substrate and more particularly the paints themselves (aqueous paints, solvent paints, powder paints), varnishes, stains and plastic resins Mention may thus be made of paints comprising the following resins alkyd resins, the most common is called glycerophta that, resins modified with long or short oil, acrylic resins derived from acrylic (methyl or ethyl) and methacrylic acid esters optionally copolymerized with ethyl acrylate, 2-ethyl acrylate hexyl or butyl, vinyl resins such as, for example, polyvinyl acetate, polyvinyl chloride, butyral polyvinyl, formalpoly vinyl, and copolymers of vinyl chloride and vinyl acetate or vinylidene chloride most often aminoplast or phenolic resins modified polyester resins, polyurethane resins, epoxy resins, silicone resins

Generally, the compositions or pigments are used at a rate of 5 to 60% by weight of the paint and 0.1 to 5% by weight of the stain

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

The compositions or pigments of the invention are particularly advantageous for paints for prepainted sheets for stamping (of the so-called "coil-coating" type) These are industrial paints used for generally painting metal panels which will be stamped after application of the painting Industrially these paints are applied according to a continuous process by spraying, drying and then baking at high temperature for very short times. This type of paint is therefore required to have good flexibility as well as good adhesion, tests are carried out for this purpose. folding These paints must also crosslink very quickly, therefore systems with catalyst are used. These paints must also have good external resistance and the dispersion of the pigments must be optimized. In fact, the thicknesses of paint deposited can be very low, of the order about ten microns for example

The invention therefore relates to paints, in particular 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. We start with a pigment based on a rare earth sesquisulfide of the type described in particular in Example 2 of European patent application EP-A-620254 II s acts of a cerium sesquisulfide Ce ₂ S ₃ doped with sodium in a Na / Ce molar ratio of 0.2 and coated with a layer of silica in a SιO ₂ / Ce ₂ S ₃ mass ratio of 4.6% This product constitutes comparison product 1

Furthermore, a suspension of product 1 is prepared in xylene at 55% dry extract using a disperser equipped with a deflocculating blade at 900 rpm. Grinding is carried out for 20 minutes at 4000 rpm. minutes A 1% solution of fluorinated di-block copolymers in tπfluoro-tπchloroethane is incorporated into this suspension so as to have a di-block rate of 1% relative to the pigment. Then the fluorinated solvent is removed by distillation with using a Vigreux column (the boiler having a temperature of around 75 ° C and the column head a temperature of 48 ° C (Téb du CCI3-CF3))

Two copolymers of formula (4) are used for the products according to the invention

- [- CH— CH ₂ -] _m - [- CH— CH ₂ -] _n -

IIY 'X' with X '= - CO— O— (CH ₂ ) ₂ - C _p F _{2p + 1}

Y '= - O— CO— CH ₃ p varying from 6 to 18

These copolymers of formula (4) also both have a xanthate ending 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 by using a copolymer of formula (4) in which m = 2 and n = 6, a product is obtained. 3 according to the invention

To verify that the copolymer has been deposited on the surface, a wetting test in water of the dried product is carried out (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

The results obtained are given in table 1 below.

Table 1

The treated products have a hydrophobic behavior, they no longer disperse in water and the contact angles with water are greater than 90 °. EXAMPLE 2

This example shows the properties of the products of the invention in their application in paint 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 disc for 20 minutes at 7000 rpm. After grinding, the ground material is recovered by filtering. on a 100 micron canvas Preparation of the paint

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

SOLVESSO150 (75%) DOWANOL PNB (25%) (solvents) 6.51 g CYCAT 4040 (paratoluene sulfonic acid catalyst PTSA) 1 g Drying conditions

The tests comprise an air drying phase of one hour (time necessary for the evaporation of the solvents) The crosslinking conditions are a temperature of 140 ° C. and a duration of twenty minutes For the evaluation tests of the thermal resistance, a temperature sweep was carried out from 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

Colonmétπe Measurement conditions

The coloπmétπques measurements are carried out according to ISO 7724 standard using a DATACOLOR DC3890 spectrocoloπmeter The measurement conditions are as follows - specular excluded (we only measure the backscattered intensity)

- ultraviolet rays are filtered at 100%

- the results are expressed under the illuminant / observer pair C / 10 °

The measurements were carried out on contrast cards, the paint being applied at 150 microns wet The results are given in table 2 below

Table 2 30 AIR DRYING, 20 140 ° C

Opacity

The evaluation of the opacity is carried out as follows. The paint to be tested is applied to polyester films at 50, 100 and 150 microns in wet. For each film, the dry thickness deposited 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 color difference (dE ^* ) between the white background and the black background We trace the color difference curve as a function of the thickness for each paint Finally, the color difference is extrapolated for each paint to an identical thickness for each sample The results are given in table 3 below

Table 3

30 'AIR DRYING, 20' 140 ° C PET OPACITY

The products of the invention, and in particular product 3, significantly improve the opacity rheology

The rheology of the paints was evaluated with the CARRIMED CSL 100 rotary rheometer by performing a speed gradient sweep from 0 to 100 s " ¹ then a plateau at 100 s ^-1 and a descent in speed gradient 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 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 Table 4

These measurements show that the paints comprising a product according to the invention have 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 more greater flexibility of use in the application environment than those of the prior art

Mechanical strength Various tests have been implemented in order to assess the flexibility and the adhesion of the paint films. The adhesion is evaluated by a grid test (standard ISO 2409) "a grid is made with a grid of 100 tiles of one millimeter on the side, we apply an adhesive tape on the grid, we remove the tape and we evaluate the state of the grid by a note going from 0 (no peeling of the paint) to 5 (the paint is completely peeled)

The flexibility of the paint film is tested using the following tests

- the ERICHSEN stamping test (ISO 1520 standard) a steel ball is applied at a constant stress and speed on the back of the plate to be tested, this ball deforms the plate, the penetration distance of the ball at which the paint begins to crack

- the deformation test using a cylindrical-conical mandrel the paint plate to be tested is deformed on a cylindrical-conical mandrel, note the radius of curvature of the mandrel at which the paint begins to crack

The results are given in Tables 5 and 6 below Table 5 Results in adhesion

30 'AIR DRYING. 20 '140 ° C PLATE AL36

Table 6 Flexible results

30 'AIR DRYING, 20' 140 ° C AL36 PLATE

^* 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 either the flexibility of the paint film or its adhesion. It can therefore be assumed that the copolymers deposited have indeed remained on the surface of the pigment and that there has been no no migration to the film interfaces otherwise the values given above would be wrong

Resistance to acids:

Acid resistance is evaluated on dry paint

A drop of 90% sulfuπque acid in water is deposited on the paint film to be tested. The variations in color are measured every minute using a coloπmeter equipped with automatic measurement acquisition and under the conditions of measurement given above in the colorimetry paragraph. The results are expressed by giving the speed initial at which the color varies (dE * / mιn) The results are given in table 7

Table 7

The products according to the invention have a pronounced protective effect

Thermal resistance of paints

"Coιl-coatιng" paints have relatively high baking temperatures. It is therefore necessary to evaluate the thermal resistance of the pigments. In effect under the action of heat, the pigment can oxidize and pass from the sulphide 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 paint. The samples crosslinked at 200 ° C will be used as a reference.

The gloss monitoring results are given in table 8 which follows and in which the variation in brightness Δ is indicated between 200 ° C. and 280 ° C.

Table 8

PLATE AL36. THERMAL DRYING AIR HOLD 30 ', 2' OVEN TRACKING GLOSS 20 °

In terms of variation in gloss, there is a marked 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. Polyamide 12 granules (natural Rilsan AMN D from the company Atochem not UV protected) are mixed with the rotating cube with the pigment (1% by weight). (either product 1 comparative or product 3) and a "fixative agent butyl stearate (0.05%) The mixture is extruded on a 30 mm diameter twin screw extruder (ZSK 30 from Werner & Pfleiderer) then injection molding is carried out on an Arburg 35 press.

T (allrounder 350-90 220D) at 220 ° C to obtain plates of dimensions 48 x 40 x 4 mm These plates are subjected to an accelerated aging test XENOTEST (ISO 4892) under the following conditions

Irradiation conditions xenon arc lamp with suprax filters simulating about 100 times more intense solar lighting, the irradiance is regulated at 65 W / m ² Room temperature 30 ° C

Operating cycle 27 minutes of irradiation in the dry phase at t = 30 ° C then 3 minutes of irradiation in the wet phase at t = 30 ° C The humidity is supplied by spraying liquid water directly onto the plates to be tested by means of nozzles

The color difference (dE *) is measured after 2500 hours. The results given in table 9 below are obtained.

Table 9

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 pigment of the support 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 product RCL 535 from the company Millenium which has an alumina layer on the surface. in addition to a copolymer of formula (4) in which m = 10 and n = 30 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 As comparison, the pigment based on TιO ₂ without copolymer constitutes the product 5 The products 4 and 5 are used in an isocyanate acrylic paint prepared as indicated below

Preparation of the PMA grinding base (Methoxy 2, propyl acetate) 4.5 g

Butyl acetate 4.5 g MULTIFLOW (spreading agent) 0.15 g MACRYNAL SM51 ON (acrylic polyol) 19.95 g

TιO ₂ (pigment) 30gr

90 gr of glass beads of a millimeter in diameter are added. The mixture is ground in a pendraulyk equipped with a Teflon disc for 20 minutes at 7000 revolutions per minute. The ground material is recovered by filtering through a 100 micron cloth.

Painting preparation

GRINDING BASE 23.23 gr

MACRYNAL SM51 ON 70 gr Addition of hardener before application of HDB 75 MX tolonate paint (isocyanate) at 15% by mass Cooking conditions

Drying in ambient air for 1 hour then baking in a ventilated oven for 30 'at 100 ° C. The results concerning the brightness and the opacity are given in table 10 below, the measurements being made according to the methods described in l 'example 2

Table 10

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

EXAMPLE 5

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

For the preparation of the product, the procedure is as in Example 1, by preparing a suspension of the organic pigment in xylene. A copolymer of formula (4) is also used, in which m = 10 and n = 30 The product obtained constitutes product 6 By way of 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 shade ΔE between 140 ° C and 230 ° C The results are shown in Table 11 below

Table 1 1

PLATE AL36. AIR DRYING THERMAL HOLD 30 '. 2 '

In conclusion, it appears from the properties given above that the treatment of the invention does indeed lead 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 can be 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 at the interfaces of the paint film. This point is essential for the adhesion of the paint with its support and the other coats of varnish or paint that can be applied. Indeed, in industrial paint applications, 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 dispersing the pigments partially desorbed and altering the adhesion of the paint The deposition of the copolymers has a double role II offers a barrier to water and oxygen and a compatibilizing effect with the paint which improves the dispersion of these pigments

Claims

1 - Composition characterized in that it comprises

- a support based on a pigment,

a layer at least partially 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 sulfide, more particularly a rare earth sulfide which contains at least one alkaline and / or alkaline earth element of which at least part is included in the crystal lattice of said sulfide

4- Composition according to claim 3 characterized in that the rare earth sulfide consists of whole monocrystalline grains of average size of at most 1.5 μm

5- Composition according to claim 3 or 4, characterized in that the rare earth sulfide is a sesquisulfide

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 amount

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 sulfide is sesquulfide of ceπum Ce S3 γ 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 first layer based on the abovementioned copolymer, this second layer being based on at least one oxide capable of having OH surface groups

1 1 - Composition according to claim 10 characterized in that the abovementioned oxide is chosen 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 also has at least one other block compatible with the medium of application of the composition

13- Composition according to one of the preceding claims, characterized in that the block copolymer is chosen from those corresponding to the formulas (1 a) (1 b), (1 c) below

(1 a) - [- A _m - B _n -] Θ—

(1 b) - [- A _m1 - B - A _m2 -] _θ -

(1 c) - [- B _n1 - A _m - B _n2 - the—

in which

- (- A -) - is a block of formula

Y

I - [- C— (- CW = CW—) _a - CH ₂ -] -

I

Y '

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

X

I - [- C— (- CV = CV—) _b - CH ₂ -] -

!

X '

and where - V, V, W and W, identical or different, represent H, an alkyl group or a halogen, - X and X ', identical or different, represent H, a halogen or a group R ¹ OR ¹ , OCOR ¹ , NHCOH, OH, NH ₂ , NHR ¹ , N (R ¹ ) ₂ , (R ^' ) ₂ N ⁺ O -, NHCOR ¹ , CO ₂ H, CO ₂ R ¹ CN, CONH ₂ , CONHR ¹ or CONR ¹ , in which R ¹ is chosen from alkyl, aryl, aralkyl, alkaryl, alkene or organosilyl groups, optionally perfluorinated and optionally substituted by one or more carboxyl, epoxy, hydroxyl, alkoxy, ammo, halogen or sulfonic groups, with the condition that at least one of X and X 'and or R ¹ is a fluorine atom and or at least one of the R-substituents ¹ is a fluorine atom, Y and Y 'identical or different, represent H, a halogen other than fluorine or a group R ² , OR ² , OCOR ² , NHCOH, OH, NH ₂ , NHR ² , N (R ² ) ₂ , (R ² ) ₂ N ⁺ O-,

NHCOR ² , CO ₂ H, CO ₂ R ² , CN, CONH ₂ , CONHR ² or CONR ² ₂ , in which R ² is chosen from alkyl, aryl, aralkyl alkaryl, alkene or organosilyl groups, and optionally substituted by one or several carboxyl groups epoxy hydroxyl, alkoxy, ammo, halogen other than fluorine or sulphonic - a and b identical or different, are worth 0 or 1,

- θ is an integer equal to or greater than 1

14- Composition according to claim 13, characterized in that the fluorinated block

X

I

- [- C— (- CV = CV—) _b - CHr -] -

I

X '

is the block in which b = 0, X 'is hydrogen and X represents a group R ¹ , OR ¹ , OCOR ¹ , C0 R ¹ , R ¹ being as defined above and with the aforementioned condition, and being able to be more particularly an alkyl radical

15- 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 - R ¹ , R ¹ being an alkyl radical, X can thus be even more particularly the group - CO - O - (CH ₂ ) ₂ - C _p F _{2p +} ι 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 Y

I

- [- C— (- CW = CW—) _a - CH ₂ -] _m -

IY 'is the block in which a = 0, Y' is hydrogen and Y represents a group R ² , OR ² , OCOR ² , CO ₂ R ² , R ² being as defined above and being more particularly a alkyl radical

17- Composition according to one of the preceding claims, characterized in that the block copolymer has a number of fluorinated units or blocks B between 2 and 20 and a number of other non-fluorinated units or 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 mainly arranged in such a way that the fluorinated block is located in the external part of the layer and the other block is located in the inner part of the layer

19- Process for the preparation of a composition according to one of the preceding claims, characterized in that the support is brought into contact with the block copolymer and the copolymer is precipitated on the support

20- A method 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 second solvent, then the second solvent is removed, whereby the block copolymer is precipitated on the support

21- The method of claim 20, characterized in that as the first solvent is used a solvent which preferentially solubilizes the non-fluorinated chain of the copolymer compared to the fluorinated chain

22- Colored pigment, characterized in that it consists of, 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 the plastics, rubbers, ceramics, glazes, papers, inks, cosmetic products, dyes and laminated coatings, characterized in that they comprise a composition or a colored pigment as defined in any one of claims 1 to 18 and 22 24- Painting, characterized in that it comprises a composition or a colored pigment as defined in any one of claims 1 to 18 and 22

25- A paint according to claim 19, characterized in that it comprises at least one resin of the acrylic or polyester type.