FR2760242A1 - Composition for coating supports with variable porosity - Google Patents

Abstract

Composition used, in particular, for coating exterior surfaces comprises in successive or simultaneous addition an aqueous phase comprising solution or dispersion of polyol(s) with glass transition temperature (Tg) no greater than 100 deg C, advantageously no greater than 50 deg C; and an isocyanate sub-composition already or to be emulsified in the same aqueous phase. Also claimed are use of said composition for coating of variable porosity; and method for preparation of said coating.

Description

COATING FOR EXTERIOR, COMPOSITION USEFUL FOR THESE
COATINGS AND METHOD FOR OBTAINING THESE COATINGS
The present invention relates to an exterior coating, a composition useful for such coatings and a process for obtaining these coatings.
It relates more particularly to the combination of certain polyols with certain isocyanate shaping.

 Such compositions are especially useful for varnishes and paint, but they may be useful for any application using the isocyanate condensation properties.

 In the remainder of the present description, the term "dispersion" will be used for polymers with hydroxyl functional groups and especially polyols, although the expression "emulsions for isocyanates, blocked or otherwise, will be used.

 The use of organic solvents is increasingly criticized by the authorities in charge of safety at work, because these solvents, or at least some of them, are considered toxic or chronotoxic. This is the reason why we try to develop more and more techniques that replace the techniques in a solvent medium or that reduce the amount to overcome the disadvantages associated with solvents.

 One of the most commonly used solutions is the use of emulsions or dispersions in water.

 In order to produce paint or varnish films, two dispersions are mixed, an emulsion containing the isocyanate which can be blocked and a dispersion of polyol.

 The mixture of dispersions may also contain pigments and fillers is then deposited on a support in the form of a film using conventional techniques of implementation of industrial paints. When the preparation contains blocked isocyanates, the film plus support assembly is fired at a temperature sufficient to ensure the deblocking of the isocyanate functional groups and the condensation of these with hydroxyl groups of the polyol particles. However, such techniques are almost impossible to carry out outdoors.

 In the present description, the particle size characteristics often refer to dn type notation where n is a number from 1 to 99, this notation is well known in many technical fields, but is somewhat rarer in chemistry, so can it is useful to recall the meaning.

This notation represents the particle size such that n% (by weight, or more exactly by weight, since the weight is not a quantity of material but a force) of the particles is less than or equal to said size.

In the remainder of the description, use will be made of the polydispersity index, which is defined as = (d90-d1 0) / d50
Typically, the ratios of average sizes (d50) between the isocyanate emulsion and the polyol dispersion are between 2 and 200. Thus, the average sizes of the isocyanate emulsions manufactured according to the technique described in the French patent application filed. on 31.03.1993 under the number 93 03795 and published under the number 2703358 the 07.10.94, have average sizes between 0.1 and 10 micrometers and more generally between 0.3 and 2 micrometers. The polyol dispersions used in combination with these emulsions have average sizes measured by quasi-elastic light scattering of between 20 and 200 nanometers and more generally between 50 and 150 nanometers.

 When dispersions of different sizes are mixed, which is generally the case, so as to obtain molar ratios between the NCO and OH groups of between 0.3 and 10 and more preferably between 0.8 and 1.5, instability of the mixtures of the two dispersions is observed.

 By way of example, this instability results in a rapid macroscopic separation, in a few minutes in general, to give on the one hand a fluid phase and on the other hand a very viscous phase.

 It follows not only an impossibility to keep (store) these mixtures, but also an extreme difficulty to apply this mixture on the surface that is desired to cover according to the usual techniques of application of paints and varnishes. If one makes sure to apply these unstable mixtures on a support, such as on a glass or metal plate, the resulting film is not transparent but appears opaque and heterogeneous and therefore not suitable.

 These problems are particularly acute in the case of isocyanates, masked or not, when they are mixed with insoluble polyols, dispersed in water.

 In addition, in the case of paints intended for outdoor use, the coating must be resistant to the weather and in particular to important temperature variations which may be of the order of 30 to 50.degree.

 This is why one of the aims of the present invention is to provide a composition which makes it possible to produce high quality exterior paints that withstand bad weather.

 Another object of the present invention is to provide a composition of the above type which requires little or no solvent.

 Another object of the present invention is to provide a composition of the above type which is rapidly (at most two hours) dust-free.

These and other objects which will appear later are achieved by means of a composition useful in particular for external coatings characterized by the fact that it comprises for successive or simultaneous addition
An aqueous phase comprising a polyol dispersion whose
glass transition temperature (tg) is less than OOC,
advantageously at -10 ° C., preferably at -20 ° C., see -30 ° C. in the
very rigorous country;
An isocyanate sub-composition already or to be emulsified.

 Obtaining polyol and especially polyol latex at low glass transition temperature can be achieved by making a polymer or rigid comonomers are avoided (eg styrene vinyl benzene) and or the alcohol esters are avoided. short chain (methyl or ethyl) and where acrylates are preferred to methacrylates. Thus the replacement of methyl methacrylate with butyl acrylate makes it possible to significantly lower the glass transition temperature and to reach the above values.

 Advantageously, the polyol may comprise carboxylic or sulphonic ionic groups, but it may also contain no ionic group.

 In the context of the present invention, it has been shown that the presence of anionic carboxylate function (-CO 2 -) significantly increases the drying kinetics, which is particularly advantageous for obtaining a fast "dust-free", especially when operating outside. A significant effect can be noted for a ratio of at least one carboxylic function to about 20 reactive hydrogen functions [alcohol or phenol function], preferably at a ratio of one to about 10, preferably at a ratio of one for about 5; however, it is desirable that this ratio be at most equal to a function for a function, preferably a carboxylic function for two ol functions. The countercations of the carboxylates advantageously correspond to the same preferences as those expressed for the counter cation of the compound according to the present invention.

 The polyol may already be in an aqueous medium or water-soluble or water-dispersible.

 It may be an aqueous solution (which may in particular be obtained after neutralization of the ionic groups) or an emulsion of the polymer in water or a latex-type dispersion.

 It seems possible to disperse a standard polyisocyanate in a water-soluble polyol under certain formulation conditions (in particular with a pigment-to-binder ratio of the suitable paint). However, the use of standard polyisocyanates with hydrodisperse polyols (resin emulsion or latex types) often poses incompatibility problems (flocculation, appearance of several phases, etc.). One of the many advantages of the preparation according to the invention is that it offers great freedom of choice for the formulation (physical form of the polyol, pigment to binder ratio, ease of incorporation into aqueous media).

 On the other hand, it was found through the use values of the coatings (in particular chemical resistance and hardness) that the crosslinking of the films was much greater when the polyol used was carboxylated.

In particular, the latexes can advantageously be used, in particular nanolatex (that is to say latex whose particle size is nanometric [more precisely whose d50 is at most equal to about 100 nanometers])
Thus, according to one of the particularly advantageous implementations of the present invention, the polyol is advantageously a latex of nanometric size having the following characteristics:
d50 between 15 and 60 nm, advantageously between 20 and 40 nm
carboxylate function of 0.5 to 5% by weight
ol function: between 1 and 4% advantageously between 2 and 3%
solid rate: between 25 and 40%
a d80 less than 1 micrometer
In addition, the latexes, especially when their glass transition point is below 0.degree. C., advantageously at -10.degree. C., preferably at -20.degree. C., make it possible to obtain, even with aromatic isocyanates of good quality, weather resistance and especially temperature variations.

 The molar ratio between the free isocyanate functions and the hydroxyl functions is between 0.5 and 2.5, advantageously between 0.8 and 1.6, advantageously between 1 and 1.4.

 The latices (non-functionalized to isocyanate optionally masked) described in the French patent application filed on April 28, 1995, No. 95/05123 and in the European patent application Ref. No. EP 0,739,961 give very good results for a better understanding of this passage we can refer to this text.

 Thus, advantageously, the latex particles have an acidic (advantageously carboxylic) content, accessible between 0.2 and 1.2 milliequivalents / gram of solid material and they have a primary accessible alcoholic content content of between 0.3. and 1.5 milliequivalents / gram.

 Thus, as indicated in this document, the latexes consisting of particles carrying function (s) according to the invention are preferably hydrophobic and advantageously have a size (dg0) generally of between 0.01 micrometre and 10 micrometers and preferably at most equal to 5 micrometers, or even 2 micrometers. They are calibrated, monodisperse and present in the latex in an amount ranging from 0.2 to 65% by weight of the total weight of the latex.

 The weight average molecular weight (Mw preferably determined by gel permeation chromatography, known by the acronym "GPC") of the polymers constituting the particles of the population A is advantageously between 5.104 and 5.106, preferably 0.8 105 and 2.106 ..

 The alcoholic functions or the acid functions, preferably carboxylic functions can also be obtained by hydrolysis of alcoologenic functions (ester, ether, halide, etc.) or acidogenic functions (ester, anhydride, acid chloride, amide, nitrile, etc. ).

The distribution between the different types of patterns advantageously meets the following rules:
The content of the unit derived from the monomer consisting of said free alcohol having an activated ethylenic function, and based on all the units of any kind, is advantageously between 3 and 15%, preferably between 4 and 10% (mole, or equivalent ).

According to an advantageous embodiment of the present invention, the unit is derived from an ester, an alpha ethylenic acid, with a diol including one of the alcohol functions.
According to an advantageous embodiment of the present invention, the unit is derived from an ester, an alpha ethylenic acid, with a diol whose alcohol function remains unesterified. Said diol is advantageously an omega / omega-diol, advantageously chosen from butanediol-1,4, propane-1,3-diol and glycol.

 It is desirable that said alpha ethylenic acid is an optionally substituted acrylic acid.

 According to a preferred embodiment of the present invention, the content of the unit derived from a free carboxylic acid (or in the form of one of its salts), and referred to all the units of any kind, is between 2 and 10% (mole).

 For economic reasons, it is often advantageous for said free acid to be an optionally monosubstituted acrylic acid or a salt thereof.

 The particles resulting from the present invention may consist of two distinct polymers, the first constituting the core and the second constituting the periphery. This type of particle can be obtained by epipolymerization [where a latex seed is covered by surface polymerization (epipolymerization, sometimes referred to as overpolymerization)) of a separate polymer. The heart is sometimes called germ by analogy to the phenomenon of crystallization. In this case, only the second polymer, that is to say the surface polymer, meets the concentration constraints to the different functions according to the present invention.

 The mass ratio between the isocyanates to be suspended and said compounds comprising an anionic function and advantageously a polyethylene glycol chain fragment is most often at most equal to 1/3, advantageously at most equal to approximately 20%, preferably at least 10 %.

(In this description the term "about" is used to highlight the fact that, when the rightmost digit (s) of a number are zeros, these zeros are position zeros and not digits. significant, except of course if specified otherwise).

 The mass ratio between the isocyanates to be suspended and said compound comprising an anionic function and advantageously a polyethylene glycol chain fragment is advantageously greater than 1%, preferably 2%.

 It is also desirable that the amount of said one or more compounds having an anionic function and advantageously a polyethylene glycol chain fragment corresponds to a value of between 10 -2 and 1, advantageously between 5 × 10 -2 and 0.5 atom of E per liter. (see infra - formula 1).

2%, preferably 4%, and at most equal to about 20%, preferably about 10%, and this weight ratio is advantageously between and about 20%, preferably between 4 and about 10%.

 According to a particularly advantageous embodiment of the present invention, after dispersion or emulsion, the sum of the constituents of the binder (that is to say, the mass contents of the or isocyanates, emulsifiers and polyols) in water varies from 30 to 70% with respect to the totality of the composition.

 The isocyanate emulsions can be made in various ways and with various surfactants it is possible to use on the one hand the surfactants which are described in the published patent application EP 691,993 filed in the name of the applicant under French priority N 93/03795 and No. 93/03796 and secondly the technique described therein, or of course both sets.

 According to a preferred embodiment of the present invention, self-emulsifying compositions are used as described in Application No. 96/02710 of February 29, 1996 and in the PCT application claiming priority.

Thus, as mentioned in the above application, it is possible to use emulsions prepared from isocyanate-based composition (s), advantageously not masked, comprising at least one compound comprising an anionic function and advantageously a fragment of polyethylene glycol chain of at least 1, preferably at least 5 ethylenyloxyl units (II)
II
Thus the present invention aims for successive or simultaneous addition, a composition comprising in particular:
a sub-composition vector of isocyanate functions whose
preferred features will be further specified and a surfactant containing at least one compound having a
anionic function and advantageously a chain fragment
polyethylene glycol of at least 1, preferably at least 5 units
ethylenyloxyls (-coc-);
optionally an aqueous phase.

 According to the present invention, said compound may be used alone, or in admixture with one or more surfactants. The latter may be agents that also fulfill the above obligation to include an anionic function and advantageously a polyethylene glycol chain fragment, preferably of at least 5 ethylenyloxyl units.

These optional surfactants may also be chosen from other ionic compounds [in particular sulphate or aryl phosphate (s) and / or alkyl (s) (of course aryl especially includes alkylaryls and alkyl especially includes aralkyls), aryl- or alkyl-phosphonate, phosphinate, sulphonate, fatty acid salt and / or zwitterionic] and among the nonionic compounds those blocked end of chain or not. (However, nonionic compounds with alcoholic functions on at least one of the chains appear to have a slightly adverse effect on the (auto) emulsion even if they have a favorable effect on other aspects of the paint composition; In view of this, it is preferable for the content of this type of compound to represent at most one-third, advantageously at most one-fifth, preferably at most one-tenth, by mass of said anionic compounds according to the invention.
Advantageously, said compound comprises a hydrophilic part formed of said anionic function, said (optional) polyethylene glycol chain fragment and a lipophilic part based on a hydrocarbon radical.

 Said lipophilic portion is generally selected from alkyl groups [in the present description ALco-yl is taken in its etymological sense of a hydrocarbon residue of an ALC-ol after ignorance of the alcohol (or ol) function]; and aryls. When the number of ethylene glycol function is at most equal to 5, the single alkyls are advantageously branched, advantageously from C 8 to C 12, the C 12 to C 16 aralkyls, the C 10 to C 14 alkylaryls and the simple aryls are C 10 to C 16. lipophilic can vary widely, especially when the number of ethylene glycol units is above 10, it can thus constitute a hydrocarbon radical of at least 1, advantageously at least 3 and having at most 25 advantageously at most 20 carbon atoms.

Advantageously, said compound has the following formula I.

Where q represents zero or 1;
where p represents an integer between 1 and 2 (closed intervals, ie
including the terminals)
where m represents zero or an integer between 1 and 2 (closed intervals this is at
say including the terminals);
where X and X ', similar or different, represents an arm with at most
two carbonaceous links;
where s is zero or an integer chosen from 1 to 30, advantageously between 5 and
25, preferably between 9 and 20 (closed intervals ie
including the terminals)
where n is zero or an integer chosen from 1 to 30, advantageously between 5 and
25, preferably between 9 and 20 (closed intervals ie
including the terminals);
where E is an element chosen from carbon and the metalloid elements of
atomic ranks at least equal to that of phosphorus and belonging to the
column VB or chalcogen of atomic rank at least equal to that
sulfur
where R1 and R2, similar or different, represent a radical
hydrocarbon, advantageously chosen from aryls and alkyls
optionally substituted.

Although this is not one of the preferred compounds, it should be noted that s and / or n may be zero, with the proviso that E is phosphorus and that when s and n are zero, respectively R1 and / or R2 are C8 to C12 alkyl, preferably branched, or C12 aralkyl to
C16 or a C10 to C14 aryl alkyl.

 One of the divalent radicals X and X 'may also be a radical of the type ([EOm (O-) p]) so as to form pyroacids, such as the symmetrical or non-symmetrical diesters of pyrophosphoric acid.

 The total carbon number of the anionic compounds of the present invention is preferably at most about 100, preferably at most about 50.

The radicals divalent X and optionally X 'are advantageously chosen from divalent radicals consisting of (the left part of the formula being bonded to the first E):
when E is P, one of X or X may be OP (O) (O -) - X "-;
> when E is P, one of X or X 'can be -O- (R10-O) P (O) -X "-; (R10
being defined below) (X "representing an oxygen or a single bond)
a direct bond between E and the first ethylene of said fragment of
polyethylene glycol chain;
<the optionally substituted methylenes and in this case
advantageously functionalized in part;
the structure arms -Y- and structure -DY-, -YD-, -YD-Y '
where Y represents a chalcogen (advantageously chosen from
the lightest ones, namely sulfur and especially oxygen),
metalloid elements of the atomic ranks at most equal to that
phosphorus and belonging to column VB in the form
tertiary amine or phosphine derivatives (the radical
ensuring tertiary character being advantageously from
plus 4 carbons, preferably not more than 2 carbons)
where D represents an optionally substituted alkylene,
functionalized, D being advantageously ethylene or
methylene, preferably ethylene in structures -DY
and especially -YD-Y ', and methylene in the structures -YD-,
Thus, E represents an atom chosen from carbon atoms (advantageously in this case m = 1 and p = 1, the prototype of this type of compound is an alcoholic acid [For example lactic or glycolic acid] polyethoxylated) the atoms giving the pnictures (elements of the column
VB) (advantageously in this case m = 1 or 0 and p = 1 or 2), chalcogen atoms of rank greater than oxygen (advantageously in this case m = 1 or 2 and p = 1 and q = 0) .

Thus, in the case where E is chalcogenous, formula I is advantageously simplified to:

Advantageously, E represents carbon and especially phosphorus or sulfur, preferably phosphorus:
in the latter case the formula (I) becomes the formula (II)

With when q is zero:

Where p represents zero or an integer between 1 and 2 (closed intervals ie
including the terminals);
where m represents zero or an integer between 1 and 2 (closed intervals ie
including the terminals)
where the sum p + m + q is at most equal to three;
where the sum 1+ p + 2m + q is equal to three or five;
where X and X ', similar or different, represent an arm with at most
two carbonaceous links;
where n and s, similar or different, represent an integer chosen between 5 and 30
advantageously between 5 and 25, preferably between 9 and 20 (intervals
closed, ie including the terminals); where R1 and R2, similar or
different, represent a hydrocarbon radical, advantageously chosen
among the aryls and alkyls optionally substituted in particular by
halogen atom, especially fluorine.

 The periodic table of elements used in this application is that of the supplement to the Bulletin of the Société Chimique de France, January 1966, No. 1.

 The optional functionalization of the alkoylenes and especially methylenes (X and X ') is made by hydrophilic functions (tertiary amines and other anionic functions including those described above [EOrn (O-) PJ).

 The counter-cation is advantageously monovalent and is chosen from inorganic cations and organic cations advantageously non-nucleophilic and consequently of quaternary or tertiary nature (in particular column V onium such as phosphonium, ammonium or even column VI such as sulfonium ) and their mixtures, most often ammoniums, generally derived from an amine, advantageously tertiary. Advantageously, it is avoided that the organic cation has a hydrogen reactive with the isocyanate function. Hence the preference for tertiary amines.

Mineral cations can be sequestered by phase transfer agents such as crown ethers
The pKa of the cations (organic [ammonium] or mineral) is advantageously between 8 and 12.

 The cations and in particular the amines corresponding to the ammoniums advantageously have no surface-active property, but it is desirable that they have a good solubility, in any case sufficient to ensure that of the said compounds comprising an anionic function and advantageously a polyethylene glycol chain fragment. in the aqueous phase and at the concentration of use. Tertiary amines having at most 12 atoms, advantageously at most 10 atoms, preferably at most 8 carbon atoms per function "onium" (recall that it is preferred that there be only one per molecule) are preferred. The amines may comprise other functions and especially the functions corresponding to the functions of amino acids and cyclic ether functions such as N-methylmorpholine, or not. These other functions are advantageously in a form which does not react with the isocyanate functions and does not significantly alter the solubility in the aqueous phase.

 It is highly desirable that the anionic compounds according to the present invention are in a neutralized form such that the pH which it induces during dissolution or contact in water is at least equal to 3, advantageously at 4, preferably at 5 and at most equal to 12, advantageously at 11, preferably at 10.

 When E is phosphorus it is desirable to use mixtures of monoester and diester in a molar ratio of between 1/10 and 10, advantageously between 1/4 and 4. Such a mixture may further comprise from 1% to about 20% (it is however preferable that it does not exceed about 10%) by mass of phosphoric acid (which will be advantageously salified at least in part so as to be in the areas of the recommended pH). And from 0 to 5% of pyrophosphoric acid esters.

 The mass ratio between the surfactant compounds (including said compound having an anionic function and preferably a polyethylene glycol chain moiety) and the isocyanates is most preferably from 4 to about 10%. The recommended areas will be explained later.

 The composition may further comprise a catalyst advantageously latent (releasable by the action of external agents, for example visible radiation or U.V., oxygen).

 The isocyanate composition according to the invention may comprise, after dispersion or emulsion in an aqueous phase, a water content of 10 to 70%. The emulsion is an oil-in-water emulsion.

 However, in the course of the study that led to the present invention, particularly in the case of aliphatic isocyanates (i.e., linked to the hydrocarbon backbone (i.e., containing both hydrogen and carbon) via a saturated carbon (sp3) It has been shown that it has a risk of runaway of various reactions when certain proportions of water is reached, so is it wise to avoiding compositions in which the mass ratio between, on the one hand, the quantity of water in the aqueous phase and, on the other hand, the sum of the isocyanate and the surfactant according to the invention, is between 10 -2 and one half. If more safety is desired, polyol (for example trimethylol propane) is generally triol (advantageously primary or even further on the definition of the polyols) and especially the most common ones, namely those of the isocyanurate type, also called trimer, uretidine dione structures, also called dimer, biuret or allophanate structures or a combination of this type of structures on a single molecule or in a mixture.

If it is desired to strongly lower the solvent content of the composition, especially when it is in the form of an emulsion, it is preferable to use mixtures of this type naturally (that is to say without the addition of a solvent). low viscosity. The compounds having this property are especially the derivatives (isocyanurate type, also called trimer, structures uridine dione, also called dimer, biuret or allophanate structures or a combination of this type of structures on a single molecule or in mixture) in part and or all of the aliphatic isocyanates whose isocyanate functions are linked to the backbone via ethylene moieties (for example polymethylene diisocyanates, in particular hexamethylene diisocyanate and those of arylenedialkoylediediisocyanates whose isocyanate function is distant from the aromatic rings of at least two carbons such as (OCN- [CH2] t - [CH2] U-
NCO) with t and u greater than 1). These compounds or mixtures advantageously have a viscosity of at most about 3000 centipoise (or millipascal.second), preferably about 1500 centipoise (or millipascal.second).

 When these values are not reached It is then often useful to bring the mixture to these viscosity values by the addition of a minimum amount of appropriate solvent (s). As already mentioned above, the The isocyanates concerned may be mono-, di- or even poly-isocyanates.

Advantageously, these derivatives may contain structures of the isocyanurate type, also called trimer, structures uretidine dione, also called dimer, biuret or allophanate structures or a combination of this type of structures on a single molecule or in mixture.

The monomeric isocyanates can be:
aliphatic, including cycloaliphatic and arylaliphatic, such as:
as simple aliphatic, polymethylenediisocyanates and
in particular hexamethylene diisocyanate;
as partially "neopentyl" aliphatic partially
cyclic (cycloaliphatic) isophorone diisocyanate (IPDI)
as cyclic aliphatic (cycloaliphatic) diisocyanate those
norbornane derivatives;
arylenedialkylidenediisocyanates (such as OCN-CH2-CH2-
NCO part of which does not show any essential difference
with aliphatics namely those whose isocyanate function
is distant from the aromatic rings of at least two carbons
such that (OCN- [CH2] t-4) - [CH2] U-NCO) with t and u greater than 1;
or else aromatic such as toluylene diisocyanate.

The preferred polyisocyanates contemplated by the technique of the invention are those in which at least one, advantageously two, preferably three of the following conditions are met. At least one, advantageously at least two, of the NCO functions are
connected to a hydrocarbon skeleton, via a carbon
saturated (sp3), preferably with at least one, more preferably at
at least two of the following conditions:

At least one, advantageously two, of said saturated carbons (sp3)
carries at least one, advantageously two, hydrogen (s), (in
other term it was found that we obtained better results
when the carrier carbon of the isocyanate function carried a
hydrogen, preferably two hydrogens) at least one, advantageously two, of said saturated carbons (sp3) are
themselves carried by a carbon, advantageously aliphatic (that is to say
hybridization sp3), itself carrying at least one, advantageously two,
hydrogen (s); in other words, it was found that better
results when the carrier carbon of the isocyanate function was not
so-called "neopentyl" position
All the carbons through which the functions
areocyanates are connected to the hydrocarbon backbone, are
saturated carbons (sp3), which are advantageously partly
preferably all of them, carrying a hydrogen, preferably two
hydrogen; in addition it is advantageous that said saturated carbons
(sp3) are at least partly (advantageously one-third of
preferably two thirds), preferably in full, themselves worn
by a carbon, advantageously aliphatic (i.e.
hybridization sp3), itself carrying at least one, advantageously
two, hydrogen (s); in other words, it was found that one was getting
better results when the carrier carbon of the function
isocyanate was in the so-called "neopentyl" position
Especially well suited are those who have at least partly a
isocyanuric skeleton or biuret (whether this skeleton is derived from a single or
several monomers, see below) and more specifically
isocyanurate type, also called trimer, uretidinedione structures,
also called dimer, biuret or allophanate structures or a
combination of this type of structures on a single molecule or in a mixture.

When the polyisocyanates are relatively heavy, that is to say that they contain at least 4 isocyanate functional groups, the first two conditions become:
At least one third, advantageously two-thirds, of the NCO functions are
connected to a hydrocarbon skeleton, via a saturated carbon
(Sp3);
At least one third, advantageously two-thirds, of said carbons
saturated (sp3) carries at least one, advantageously two,
hydrogen (s), (in other words it has been found that we obtain
better results when the carbon carrying the isocyanate function
was carrying a hydrogen, preferably two hydrogens; In
furthermore, it is advantageous for said saturated carbons (sp3) to be at
less in part (advantageously one-third, preferably two-thirds),
preferably in full, themselves carried by a carbon,
advantageously aliphatic (that is to say of sp3 hybridization), itself
carrier of at least one, preferably two, hydrogen (s); in
other term, it was found that better results were obtained
when the carrier carbon of the isocyanate function was in position
called "neopentyl"
The isocyanates, especially aliphatic ones, react with some of the anionic compounds concerned. They react with the hydroxyl of the acid functions which are not or badly neutralized. These compounds are also covered by the present invention.

In particular in the case of phosphates (m = 1) they react to give compounds of the type:

but when E belongs to the phosphorus column and m (which is the same as in formula I) is equal to zero the compound becomes isomerized (or is made directly) to give:

Where E is an element of the column VA the periodic table of elements [(supplement to the Bulletin of the Chemical Society of France January 1966 N "1) advantageously phosphorus].

dans laquelle R'10 est choisi parmi les restes hydrocarbonés (semblables ou différents de R10) et une charge négative dont le point d'attache [c'est-à-dire l'atome porteur de la liaison ouverte] est un carbone dans laquelle le(s) R'11 est (sont) choisi(s) parmi les restes hydrocarbonés dont le point d'attache [c'est-à-dire l'atome porteur de la liaison ouverte] est un carbone (semblables ou différents de R10 et de R'11) et une charge négative. Where Iso is the residue (of a poly) isocyanate (after removal of an isocyanate function) where R10 is a hydrocarbon residue (i.e. containing hydrogen and carbon atoms) whose 'bond [that is to say, the atom carrying the open bond] is a carbon where R11 is chosen from:
- a negative charge;
a group of formula II:

wherein R'10 is selected from hydrocarbon radicals (similar to or different from R10) and a negative charge whose attachment point [i.e., the open link carrier atom] is a carbon in which (s) R'11 is (are) chosen from hydrocarbon radicals whose attachment point [that is to say the atom carrying the open bond] is a carbon (similar or different from R10 and R'11) and a negative charge.

It is desirable that at least one of the organic substituents (R10; R'11;R'10) comprises a polyethylene glycol chain moiety preferably of at least 5, preferably at least 7, ethylenyloxyl units. In other words, it is desirable that at least one of the organic substituents has the same formula as the substituents of E in the general formula 1. More specifically at least one of the organic substituents (R10; R'11; R '10) meets the formula

Where R5 represents an arm having at most two carbonaceous links
(with the same preferred values as X 'and X)
where n is an integer chosen between 0 and 30, advantageously between 5 and 25,
preferably between 9 and 20 (closed intervals, ie including the terminals)
where R 1 represents a hydrocarbon radical, advantageously chosen from aryls and optionally substituted alkyls.

Thus, according to an advantageous variant of the present invention, the compositions according to the present invention exhibit compounds resulting from the reaction exposed above in an overall proportion, relative to a volume of one liter of isocyanate, of from 0.01 to 1, advantageously from 0.05 to 0.5, preferably from 0.05 to 0.3 equivalent of function

 It is advantageous that the radical Iso predominantly or completely provides an aliphatic bond with the same preferences as those described above with respect to isocyanates.

Thus also part of the invention compounds of formula:

 In which R10 and R11 can take the above values but also when m is 1, be a negative charge because in some batch there may be significant amounts of residual phosphoric acid.

Of course then R10 can also be worth:

 The radical Iso may or may not be the same as that of the penultimate formula.

 In which Iso represents the remainder of a polyisocyanate, preferably a reaction product of a diisocyanate monomer to form biuret or isocyanurates (trimer), or with a di- or poly-ol, advantageously a triol or a tetra- ol.

 It is advantageous that the radical Iso predominantly or completely provides an aliphatic bond with the same preferences as those described above with respect to isocyanates.

 Advantageously Iso carries, in addition to the function shown in the formula at least one, preferably at least two isocyanate functions, preferably at least one of which is not masked, and of which, more preferably, at least two are not masked. .

This purpose and others which will appear later are achieved by means of an emulsification process which comprises at least the following step: addition, advantageously with very moderate stirring, or isocyanate
in the polyol + water mixture.

 The surfactant may be either in the aqueous phase or preferably in the isocyanate phase. In the first case, the reactions between isocyanate and said compound containing an anionic function and advantageously a polyethylene glycol chain fragment are much less important.

 This agitation is preferably manual or mechanical.

 This emulsification is advantageously carried out at a temperature below 50 ° C., preferably at room temperature.

 It is desirable to carry out, if necessary, a pH adjustment (to reach a value advantageously at least equal to three, preferably to 4 and advantageously at most equal to 11, preferably 10, and therefore advantageously between 3 and 11, of preferably between 4 and 10) when emulsifying. This adjustment makes it possible to reach an advantageous zone where the first (or only) acidity of each surfactant according to the present invention is neutralized.

 According to an advantageous variant of the present invention, the pigments (and in particular the titanium dioxide) are dispersed in the polyol or polyols before the addition of the isocyanate.

 Another object of the present invention is to provide a method of applying the isocyanate-based composition to form a coating.

 These and other objects which will appear later are achieved by means of a process comprising the application of a preparation layer (that is to say of composition according to the invention comprising the aqueous phase and the constituents of the layer) whose thickness before drying is between 10 and 400 microns, preferably between 50 and 200 corresponding after drying to a thickness between 5 and 150 microns, preferably between 20 and 80 microns.

 According to one advantageous embodiment, this process comprises a drying of 20 ° C. to 60 ° C. for a duration ranging from 1/4 to 24 hours.

 Advantageously, this drying takes place in the presence of a solvent to assist in the removal of water.

 According to a particularly advantageous embodiment of the present invention, the application is carried out by spraying.

The preparation of the surfaces is well known to those skilled in the art (for example phosphatations for ferrous compounds steel or chromate for surfaces based on alumina). (We can for example refer to the following book: "organic coating technology" volume II of HF PAYNE and "Paint
Handbook "Edited by GEWEISMANTEL)
According to the present invention, it is thus possible to obtain coatings (in particular paints or varnishes) having the technical characteristics (these values depend mainly on the polyols used): implementation and characteristics of the coating
dry thickness lso2178: 45 pm
support and treatment thereof: steel treated with
phosphating: R461 plates
from supplier Q Pannel

<tb><SEP> usual <SEP> properties
<tb><SEP> minimum
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<tb> test <SEP> din <SEP> 67530 <SEP> (these <SEP> values
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<tb><SEP>I'on<SEP> wants <SEP> a <SEP> painting
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<tb><SEP> Brightness <SEP> 20 <SEP> 0.5 <SEP> 80
<tb><SEP> 60 <SEP> 0.5 <SEP> 90
<tb><SEP> hardness <SEP> Konig <SEP> iso <SEP> 1522 <SEP> 10s <SEP> 150s <SEP>
<tb><SEP> Adhesion <SEP> test <SEP> din <SEP> 53151 <SEP> GT-1 <SEP> GT-5
<tb><SEP> Resistance <SEP> at <SEP> shocks <SEP> test <SEP> 10 <SEP> cm <SEP>> 100 <SEP> cm
<tb><SEP> N iso <SEP> 6272
<tb><SEP> direct <SEP>
<tb><SEP> inverse <SEP> 5 <SEP> cm <SEP>> 100 <SEP> cm
<tb><SEP> Resistance <SEP> to <SEP> the <SEP> methyl- <SEP> 20 <SEP>> 200
<tb><SEP> ethyl ketone <SEP> (butanone)
<tb><SEP> (Double <SEP> passage)
<tb><SEP> Holding <SEP> in <SEP> Outside <SEP> QUV <SEP> 50 <SEP> h <SEP> 800 <SEP> h
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Rhodafac RE610 is a mixture of mono- and phosphoric diesters according to formula II, the average formula of its hydrocarbon radical is a polyethoxylated nonylphenol (-dix times). The molar ratio between mono ester and diester is about 1 (rounded mathematically). Similarly, RhodafacPA17 has as a product according to the present invention a mixture of phosphoric mono- and diesters according to formula II, the average formula of its hydrocarbon radical is a polyethoxylated nonylphenol (-five-six times).

Example 1 - preparation of the mixture 1
165 g of tolonate HDT (trimer-based isocyanurate oligomer) are mixed with 24 g of butyl acetate and 139 of Rhodafac RE610 (mixture of phosphoric mono- and di-esters according to formula II) and 3 g of triethylamine. This mixture is stirred with a frame or deflocculating blade for 5 minutes at 100 revolutions / minute. This mixture has a viscosity of 0.84 Pas. At 20 ° C and less than 100 APHA staining.

Example 2 - preparation of the mixture 2
the mixture has the same composition as the mixture 1 but the tolonate HDT is replaced by the tolonate HDT-LV.

 The viscosity of this mixture is 0.476 Pa.s. At 20 ° C and less than 100 APHA staining.

Example 3 - preparation of the mixture 3
the mixture is made with 929 of tolonate8 HDT and 10 g of Rhodafac RE610 and 2.3 g of triethylamine. The viscosity of this mixture is 5.2 Pa.s. At 20 ° C and less than 100 APHA staining.

Example 4
30 g of the mixture 1 is added to 20 g of water. The mixture is stirred with a paddle frame at 250 rpm for 5 minutes. This gives an emulsion whose average particle size is 1.2 pu. The size of the emulsion drops remains stable for 30 hours at a pH of between 3 and 9.

Example 5
309 of the mixture 3 is added to 209 of water. The emulsion is prepared under the same conditions as in Example 4. The average size of the drops is 1.1 μm.

Example 6 - Use of Nanolatex:
Preparation of a varnish from the mixture 1 and a nanolatexlc ie latex whose particle size is Nanometre read accurately whose d is at most equal to about 100 nanometersl) of acrylic monomers.

The nanolatex used is an experimental product produced according to the process described in the French patent application filed on April 28, 1995 No. 95/05123 and in the European Patent Ref N EP 0,739,961 of the following characteristics:
d50: about 35 nm
carboxylate function: 2.6% by weight on the dry polymer
o function: 2.6% by weight on the dry polymer
Molecular weight greater than 100,000
Dry extract in weight: 30%
pH around 8
Minimum Temperature of Film Formation about 20 "C
Glass transition temperature about 40 ° C
The varnish is prepared by incorporation with manual mixing of 4. 6 g of the mixture 1 in 45.6 g of nanolatex. This ratio corresponds to a ratio of NCO / OH functions of 1.2.

 The mixture thus prepared has a life of 4 hours, this means that for 4 hours the viscosity and the appearance of the mixture is unchanged but also that the films formed from this mixture during these 4 hours have properties such as the resistance solvent, hardness and gloss unchanged.

 The drying time of the film is remarkably short: 20 minutes for the "dust-free" time and 30 minutes for the "dry to the touch" time according to standard NF T 30037. These measurements were made on glass plates for a dry thickness 40 μm film and drying at 23 ° C with 55% relative humidity.

 Achieving a short drying time and a relatively long life of the mixture is a much sought-after advantage by paint experts.

The values of use of the coating are also globally of a very good level, we can mention:
the Persoz hardness of the 50 μm dry film measured on a steel plate after drying for 24 hours at 23 ° C. and 55% relative humidity is equal to 275 seconds.

The gloss at an angle of 20 of the film applied to a steel plate is 90
the resistance to methyl ethyl ketone of the dried film for 7 days at 23 ° C. and 55% relative humidity is greater than 200 round-trip with a soaked cotton wool.

 These excellent performances of this Nanolatexpolyisocyanate combination according to the invention are certainly attributable to the very particular physico-chemistry of these products, in particular to the very large specific surface area of the nanolatex, which promotes a great homogeneity of crosslinking in the final polymer.

Example 7
The mixture prepared in Example 13 is applied by brush with a deposit of 200 g / m 2 on a concrete type support.

 After drying for 1 hour at room temperature, the coating provides a water repellency of the support which results in a beading effect, and less water absorption. In addition, the coating has good abrasion resistance.

Example 8
Preparation of a coating from mixture 1 and a nanolatex of acrylic monomers.

Nanolatex is an experimental product according to the following feature N "invention
d50 about 35 nm
carboxylate function: 1% by weight on the dry polymer
o function: 2.6% by weight on the dry polymer
Molecular weight greater than 100,000
Dry extract in weight: 30%
pH around 8
Glass transition temperature approximately - 30 "C
The varnish is prepared by incorporation with manual mixing of 4. 6 g of the mixture 1 in 45.6 g of nanolatex. This ratio corresponds to a ratio of NCO / OH functions of 1.2.

 The coating is applied to concrete by brush at a rate of 2 layers of 300 g / m2. Its great flexibility, generated mainly by the low Tg of the nanolatex, gives it an ability to hide the cracks that may appear during the aging of the support (especially because of the expansion of the concrete due to large temperature variation).

 In addition, the crosslinking with the polyisocyanate according to the invention gives the coating excellent resistance to chemical agents and to water.

Claims (1)

1. useful composition especially for external coatings characterized  in that it comprises for successive or simultaneous addition:  An aqueous phase comprising a solution or dispersion of polyol  whose glass transition temperature (tg) is less than 0 C,  advantageously at -10 ° C., preferably at -20 ° C., see -30 ° C. in the  very rigorous country  An isocyanate sub-composition already or to be emulsified in  the same aqueous phase.