CH715170A2 - Aqueous composition for improved coating. - Google Patents

Abstract

The invention relates to an aqueous coating composition comprising at least one cationic or amphoteric film-forming polymer and at least one nonionic film-forming polymer in which the dry weight ratio of cationic or amphoteric polymer (s) relative to the dry weight of the non-ionic polymer (s) is between 20/80 and 80/20. The subject of the invention is also a coating obtained from said composition and the use of this composition for the manufacture of a coating, preferably a paint or a varnish.

Description

Description

FIELD OF THE INVENTION The invention relates to a composition for coating, more particularly a coating such as a paint or a varnish having a compromise of improved properties, in particular in terms of adhesion on various supports, isolation of stains. , resistance to wet abrasion, ease of use and reasonable economic cost. The invention also relates to a coating obtained from the preceding composition and to the use of said composition for the manufacture of a coating. The coating according to the invention is particularly intended to be applied to facades and / or interior and / or exterior walls of buildings.

STATE OF THE ART [0002] The aqueous compositions for coating are generally anionic compositions. They contain anionic polymeric binders which are in particular combined with pigments, dispersants and fillers to form the final aqueous coating ready to be applied to the support. Anionic polymers typically include anionic functional groups such as sulfate or carboxylate groups.

It is generally difficult to reconcile, for the same coating composition, properties relating to the properties of the primer primers ("primer") such as in particular a good capacity for blocking and / or isolating stains and good multi-support adhesion and more particularly that of topcoats such as high resistance to wet abrasion and a long opening time.

It has thus been proposed to functionalize anionic polymers in particular with amines, amides or acetoacetate groups in order to improve the properties, in particular the adhesion properties. However, the stain blocking properties remain insufficient.

[0005] Compositions have also been proposed comprising a combination of a film-forming polymer with ion exchange resins. Document US Pat. No. 6,815,466B2 describes in particular a composition comprising an emulsion polymer and an anion exchange resin, said composition thus exhibiting good capacity for blocking stains.

However, the ion exchange resins are in the form of particles, for example particles having a size between 0.5 and 50 microns and it is then difficult to obtain a composition having both good colloidal and sedimentary stability and good finish coat properties.

The present inventors have sought to solve the problems of the prior art by proposing a composition having both excellent properties of stability, insulation / blockage of stains, adhesion but also resistance to wet abrasion and ease of use, that is to say having a long opening time, these properties being generally contradictory.

OBJECT OF THE INVENTION A first object of the invention is an aqueous composition for coating comprising at least one cationic or amphoteric film-forming polymer and at least one nonionic film-forming polymer in which the dry weight ratio of polymer (s ) cationic (s) or amphoteric (s) relative to the dry weight of the non-ionic polymer (s) is between 20/80 and 80/20.

The cationic film-forming polymer can be chosen from acrylics, styrene-acrylics, epoxy esters, modified alkyds and alkyds, polyurethanes (PU), polyurethane and polycarbonate copolymers, vinyl esters and copolymers of vinyl ester taken alone or in combination.

The amphoteric polymer can be chosen from acrylic polymers or copolymers or alkyds taken alone or in combination.

The nonionic polymer can be chosen from polyurethanes (PU), vinyl polymers or copolymers, in particular copolymers based on vinyl acetate and vinyl ester of versatic acid, polymers based on acetate vinyl and vinyl neodecanoate or polymers based on vinyl acetate, ethylene and acrylic, taken alone or in combination.

Advantageously, the dry weight ratio of cationic (s) or amphoteric (s) polymer (s) relative to the dry weight of the non-ionic polymer (s) is between 25/75 and 75/25, more preferably between 30/70 and 70/30, more preferably still between 45/55 and 55/45 or even between 48/52 and 52/48.

According to an embodiment compatible with the preceding modes, the dry weight of cationic (s) or amphoteric (s) polymer (s) is greater than the dry weight of the non-ionic polymer (s) .

According to one embodiment, more than 70% by dry weight, preferably more than 80% by dry weight, more preferably still more than 90% by dry weight, total compounds of the composition other than said polymers are of a nature (I) nonionic or cationic when at least one cationic polymer is present or (ii) nonionic when at least one amphoteric polymer is present in the composition. According to a preferred mode, the pH is less than or equal to 7, preferably between 2 and 7, more preferably between 4 and 6.5.

Advantageously, at least one cationic or amphoteric polymer has been added in the form of an emulsion or a solution.

The invention also relates to a coating obtained from the composition described above and the use of this composition for the manufacture of a coating, preferably a paint or a varnish.

Description Unless otherwise stated, the definitions of ISO 1514 standards: "Paints and varnishes - Standard panels for tests", ISO 2808: "Paints and varnishes - Determination of film thickness", ISO 4618: 2014: "Paints and varnishes Terms and definitions ”and ISO 3251: 2008:“ Paints, varnishes and plastics - Determination of dry extract ”apply.

Coatings, in particular wall coverings, can be characterized by their resistance to wet abrasion. The latter corresponds to the resistance of the coating film to repeated washing and is determined according to ISO 11998: 2006. Thus, the more resistant the coating is to wet abrasion, the less the thickness of the film is lost during wet rubbing.

Briefly, the resistance to wet abrasion is evaluated using a wet abrasion device. A wet coating film is applied to a Leneta card. After drying for 28 days at 23 ± 2 ° C at a relative humidity of 50 ± 5%, the film is subjected to a cycle of 40 or 200 rubs (20 or 100 back and forth) according to the classification EN 13300. The loss of film thickness following wet abrasion is measured. Resistance to wet abrasion is classified using standard EN 13300 as shown in the table below.

There are five classes of resistance to wet abrasion:

Classification (EN 13300) 1 Loss of film thickness

Class 1 less than 5 μm at 200 rubs

Class 2 between 5 and 20 μm at 200 rubs

Class 3 between 20 and 70 μm at 200 rubs

Class 4 less than 70 μm at 40 rubs

Class 5 greater than 70 μm at 40 rubs A paint resistant to wet abrasion of class 1 means that its paint film loses less than 5 μm in thickness after 200 rubs.

The coatings can also be characterized according to their ability to isolate or block stains ("stainblocking" in English). This property thus makes it possible to be able to apply the coating to a stained support without said spots being dissolved and / or cannot migrate into the coating, in the various layers deposited successively, up to the free surface of said coating layers. More particularly, the spots are not or substantially less visible once one or more layers of coating have been applied to the stained support.

The term "stain" is intended to literally encompass any mark, imperfection, discoloration or any deposit, visible or not visible to the naked eye, which would affect the ability to satisfactorily cover the support with one or more layers of coating. The term "stain" therefore includes, without limitation, marks caused by inks, pencils, lipstick, grease pencils, smoke residue, tannins, water and the like. These stains can be found on residential or commercial walls, on wooden substrates, on composite wood substrates, on concrete substrates, on normally painted paper substrates with one or more layers of liquid coating.

In the context of the present invention, qualitative and comparative tests were carried out. Acrylic paint for ceiling and walls was applied to a substrate and allowed to dry for 28 days at room temperature. After this period, the surface was divided into 2 cm wide strips and on the alternating strips, sixteen stains of different nature were made on acrylic paint by applying with the most suitable tool the following compounds: black permanent marker and red, cola-based soft drink, coffee, tea, red wine, red vinegar, tannin solution, tobacco solution, colored pencil, black and red pen, rust solution, red food coloring solution, soot and red lips. The stains were left to dry overnight and then gently cleaned with dry paper to remove excess stain. Three layers of the coatings to be tested were applied successively to the stained surface, a drying time of 24 hours at 23 ± 2 ° C at a relative humidity of 50 ± 5% was systematically observed.

A quantitative evaluation was carried out using a color difference measurement determined according to the L * a * b * CIE 1976 color space, generally called CIELAB. The CIELAB space is a color space particularly used for the characterization of surface colors. Three sizes characterize the colors:

_ the clarity L * which derives from the luminance of the surface;

_ the two parameters a * and b * which express the difference in color compared to that of a gray surface of the same lightness. The existence of a gray, achromatic surface implies explicitly indicating the composition of the light which illuminates the colored surface. In the context of the present description, this light source is standard daylight D65. The CIELAB color space is defined from the CIE XYZ space. Compared to the latter, it has the advantage of a distribution of colors more in line with the perception of color differences by the human visual system. The color difference between the color (color of paint applied in ^3rd and final layer on the spot) and the color b (color of paint applied in ^3rd and final layer on the non-stained paper), AE _ab , is measured with the equation:

or :

The closer AE _ab is to zero, the more the coating has a good capacity for stain isolation.

In the context of the present description,

- "Average AE _ab " was determined and corresponds to the average of the sixteen AE _ab obtained for each of the spots;

- “AE _ab soot” has been determined and corresponds to the AE _ab obtained for a soot stain;

- “AE _ab red food coloring” has been determined and corresponds to the AE _ab obtained for a stain of red food coloring;

In the context of the present invention, the adhesion of the coating has also been evaluated according to ISO 2409: 2013. This method assesses the resistance of coatings to separation with respect to the supports on which they are applied when a right angle grid pattern is cut in said coverings, the cut penetrating into the 10 supports. The property determined by this procedure depends in particular on the adhesion of the coating to the previous layer or to the support. However, this procedure should not be considered as a means of measuring adhesion as such, but as a means of comparing the adhesion between different given coatings. A coating with the best adhesion is given a score of 0 and a higher score for coatings with lower adhesion.

The open time was evaluated using standard ASTM D7488-11 (2016). Since water-based coatings tend to dry very quickly, this often causes defects in the final appearance of the painted areas. This is particularly true for coatings comprising less than 100 g / l of volatile organic compounds for which lower amounts of solvents are present in the coating. The present method is a means of determining the possible opening time before a new coating layer can be applied in an already painted area. To do this, a layer of the coating is applied to contrast paper with an application frame. While said coating layer is still wet, a number of crosses are made with a spatula. The time to is determined and the reference crosses are repainted at given time intervals with a brush and a small amount of coating. The time ti corresponds to the time from which the crosses can no longer be completely repainted and the opening time (in hours) is the time difference between ti and t ₀ .

According to the present invention, it has been discovered that an aqueous coating composition comprising in particular the combination of at least one cationic or amphoteric film-forming polymer and at least one nonionic film-forming polymer and in which the dry weight ratio of cationic or amphoteric polymer relative to the dry weight of non-ionic polymer is between 20/80 and 80/20, makes it possible to obtain an excellent compromise of properties. These properties, generally contradictory, are in particular good adhesion on various supports, an excellent ability to isolate stains, a high resistance to wet abrasion, an ease of use due to a long opening time and a reasonable economic cost.

Within the meaning of the present innovation, the term "film-forming polymer" means a binder or a resin which, after hardening, forms on the support a continuous and adherent film, with specific properties. These polymers or macromolecules are organic or mineral compounds whose molecular weights are between 300 and 106 daltons. There are different types of film-forming polymers:

i) polymers of natural origin, such as resins and natural gums;

ii) artificial polymers, obtained by chemical reactions on natural polymers in order to modify their molecular mass and their solubility and such as cellulose nitrates;

ili) synthetic polymers mainly synthesized by the radical route in a solvent or aqueous medium (vinyl polymers), by polycondensation (polyester resins, aminoplast resins, etc.), by polyaddition (polyurethane epoxy resins).

In the field of paints and varnishes, film-forming polymers are particularly well known since they are the main element of paint and varnish compositions as indicated in particular in the manual reflecting general knowledge in the field of "Technical of 'engineer - Formulation of paints - Implementation of the polymers used', Jean-Claude Laout (Ref. J2272 v1, date of publication: 10 Sep 2005).

The film-forming polymers according to the present invention form a continuous and adherent film on the support by simple drying for 24 hours at 23 ± 2 ° C at a relative humidity of 50 ± 5%. In the context of the present innovation, polymers requiring electrodeposition or the use of photoinitiators for the formation of a continuous and adherent film are excluded from the definition of film-forming polymers. These particular polymers indeed require a completely specific deposition process to form the final film, the technical field of this process is not that of the process according to the present innovation.

Ion exchange resins in the form of beads or large particles, for example of the order of 0.1 or 0.5 μm and up to 50 μm or more are not film-forming polymers in the sense of the present invention. In addition to the fact that such resins are not capable of forming a continuous and adherent film, they do not allow good colloidal or sedimentary stability of the compositions or require to be used in combination with ionic compounds. By way of examples, the anion exchange resins can be stabilized by polymers or copolymers comprising anionic functions.

Within the meaning of the present innovation, the term “cationic polymer” means a polymer positively charged under the conditions of the composition. They are preferably polyelectrolytes, cationomers or halo-telechelic polymers. It can be pH-dependent ionic polymers such as poly (allylamine hydrochloride) or poly (N-vinylimidazole) or permanent ionic polymers such as poly (quaternized vinylimidazole). When at least one pH-dependent polymer is present in the composition, the pH is advantageously between 4 and 9, preferably between 4 and 8, more preferably between 4 and 6.5 or between 4 and 5. According to a method of realization, it is a polyamine and protonized polymer. The cationic polymer is preferably protonized by a weak monoacid such as acetic acid, formic acid or lactic acid.

The cationic polymer can be chosen from acrylics, styrene-acrylics, epoxy esters, alkyds and modified alkyds, polyurethanes (PU), polyurethane and polycarbonate copolymers, vinyl esters and copolymers of vinyl ester taken alone or in combination. As examples of such polymers, there may be mentioned:

- among acrylic polymers: dispersions of pure acrylic polymers such as Crilat 4896 (Vinavil) having a dry extract of approximately 28% or Ecronova RA 160 Plus (Michelman) having a dry extract of approximately 56% or Mowinyl 7820 (The Nippon Synthetic Chemical Industry Co. Ltd.) having a solids content of about 45%>; emulsions of pure acrylic polymers such as Ecronova RA 180 Plus (Michelman) having a dry extract of about 44%; solutions of a pure acrylic polymer such as WorléeCryl 7712 H (Worlée-Chemie GbmH) having a dry extract of approximately 40% or WorléeCryl 7712 W (Worlée-Chemie GbmH), having a dry extract of approximately 26%> or still WorléeCryl 8721 (Worlée-Chemie GbmH), having a dry extract of approximately 30%;

- among PU or polyurethane and polycarbonate copolymers: polyurethane dispersions such as Esacote MD 30 (Lamberti) having a dry extract of approximately 30% and Esacote MD 15 (Lamberti) with a dry extract of approximately 30%; dispersions of polyurethane and polycarbonate copolymer such as Alberdingk CUD 4835 VP (Alberdingk) with a dry extract of approximately 30%, the latter dispersions being particularly preferred in the compositions according to the invention because they in particular give them excellent resistance to elongation;

- among acrylic and styrene copolymers: dispersions of acrylic and styrene copolymer such as Picassian AC-146 (Sthal) having a dry extract of about 40%; the compositions comprising these dispersions are advantageous because they have in particular good resistance to wet abrasion;

- among epoxy esters: dispersions based on epoxy esters such as Duroxyn® EF 2107W / 45WA (Allnex) having a dry extract of around 45% or Duroxyn® EF 2406w / 40W (Allnex) having a dry extract of about 45%. Duroxyn® EF 2107W / 45WA gives compositions more flexibility, the composition can be applied to surfaces subject to movement such as wood. The compositions comprising Duroxyn® EF 2406w / 40W are particularly suitable for rigid supports such as in particular metals.

In the case of a combination of cationic polymers, the inventor has in particular obtained excellent results by combining a dispersion of cationic PU with a cationic acrylic emulsion or else a cationic acrylic dispersion and a cationic acrylic emulsion. These results have been obtained in particular by combining one or the other of these combinations of cationic polymers with a stabilized nonionic polymer such as a copolymer based on vinyl acetate and vinyl ester of versatic acid. According to a preferred embodiment, the cationic polymer comprises at least one protonized alkyd, advantageously in the form of an emulsion. Advantageously, it may be an alkyd obtained according to the method described in patent US8202921B2. Such a polymer makes it possible in particular to obtain a composition having excellent stain resistance.

In another preferred embodiment, optionally combinable with the previous embodiments, the cationic polymer comprises at least one film-forming acrylic polymer, preferably in the form of a pure solution preferably having a dry extract of between 25 and 45% by weight, preferably between 25 and 35% by weight. Such a polymer makes it possible in particular to obtain a composition having very good adhesion properties.

Within the meaning of the present innovation, the term "amphoteric polymer" means a polymer which can both behave as a base and which can accept one or more protons or as an acid and which can lose one or more protons.

The amphoteric polymer of the composition according to the invention can be chosen from acrylic polymers or copolymers or alkyds, taken alone or in combination. As examples of such polymers, there may be mentioned:

- among acrylic polymers: acrylic copolymers such as Hydropliolite 050 (Omnova Solutions) based on core-shell technology which incorporates adhesion promoting monomers to a dry extract of about 40%;

- among the alkyds: emulsions based on an oil-based alkyd, for example castor oil, such as Necowel 4300 (ASK Chemicals GmbH) having an oil length (35%) modified with groups cationic and a dry extract of about 43% or the emulsions based on an alkyd based on saturated fatty acids modified with cationic groups such as Necowel 4400 (ASK Chemicals GmbH) having a dry extract of about 43%.

According to an advantageous embodiment, the composition comprises at least one emulsion based on an oil-based alkyd such as in particular Necowel 4300 (ASK Chemicals GmbH) having an oil length (approximately 35%) modified with cationic groups and a dry extract of between 40 and 50% by weight (preferably around 43%) or acrylic copolymers such as in particular Hydropliolite 050 (Omnova Solutions) based on core-shell technology which incorporates promoter monomers advantageously adhesion to a dry extract of about 40% by weight. Such compositions have good abrasion resistance, in particular these compositions can be classified in class 2 according to standard EN 13.300.

Advantageously, the composition comprises acrylic copolymers such as in particular Hydropliolite 050 (Omnova Solutions) based on core-shell technology which incorporates adhesion promoting monomers preferentially to a dry extract of approximately 4% by weight, which have the advantage of not yellowing and not releasing aldehydes.

In another embodiment, the composition comprises an emulsion based on an oil-based alkyd such as in particular Necowel 4300 (ASK Chemicals GmbH) having an oil length (preferably approximately 35%) modified with cationic groups and a dry extract of approximately 43% in combination with a nonionic binder such as a copolymer of vinyl acetate and vinyl ester of versatic acid. Preferably, said copolymer can be a dispersion of vinyl acetate and vinyl ester copolymer of versatic acid, with a dry extract of about 55%. More particularly, it may be the product Polidisp 7215 (Resiquica - Résinas Quimicas, SA). Such an embodiment makes it possible in particular to obtain a composition having a wet abrasion resistance of class 1 according to EN 13300 and excellent stain-insulating properties.

Within the meaning of the present innovation, the term "non-ionic polymer" means a polymer which does not contain a filler under the conditions of the composition.

The nonionic polymer of the composition according to the invention can be chosen from polyurethanes (PU), vinyl polymers or copolymers, in particular copolymers based on vinyl acetate and vinyl ester of versatic acid, polymers based on vinyl acetate and vinyl neodecanoate or polymers based on vinyl acetate, ethylene and acrylic, taken alone or in combination. According to an advantageous mode, the composition comprises at least one PU, preferably a dispersion of PU (PUD). According to another embodiment, which can be combined with the previous embodiment, the composition comprises at least one copolymer based on vinyl acetate and vinyl ester of versatic acid, preferably an aqueous emulsion of a copolymer based on acetate of vinyl and vinyl ester of versatic acid advantageously having a dry extract of between 53 and 57% by weight.

According to a particularly preferred embodiment, the composition comprises at least one copolymer based on vinyl acetate and vinyl enodecanoate.

The “non-ionic” polymer of the composition can be chosen from:

- copolymers based on vinyl acetate and vinyl neodecanoate, in particular those in dispersion such as in particular Mowilith LDM 2110 (Celanese Emulsions GmbH) having a dry extract of approximately 50%;

- copolymers based on vinyl, ethylene and acrylic, in particular those in dispersion such as Mowilith LDM 1865 (Celanese Emulsions GmbH) having a dry extract of about 53%;

- the vinyl acetate and vinyl ester copolymers of versatic acid, in particular those in dispersion such as polymer in dispersion such as Polidisp 7215 (Resiquica -Résinas Quimicas, SA) having a dry extract of approximately 55%; or Polidisp 7218 (Resiquimica - Résinas Quimicas, SA) having a dry extract of approximately 53% or Polidisp 7252 (Resiquimica - Résinas Quimicas, SA) having a dry extract of approximately 51%;

- polyurethanes based on an aliphatic polyether isocyanate, in particular those in dispersion such as Witcobond W-320 (Lanxess AG) have a dry extract of about 35%.

The dry weight ratio of polymer (s) cationic (s) or amphoteric (s) relative to the dry weight of (non) polymer (s) non-ionic (s) is preferably between 25/75 and 75 / 25, more preferably between 30/70 and 70/30, more preferably still between 45/55 and 55/45 or even between 48/52 and 52/48.

According to an embodiment compatible with the previous mode, the dry weight of cationic (s) or amphoteric (s) polymer (s) is greater than the dry weight of the non-ionic polymer (s) .

The specific ratio of cationic or amphoteric polymer (s) relative to the nonionic polymer (s) ^) makes it possible in particular to obtain an optimized compromise of properties.

The polymers can be in the form of a dispersion, an emulsion and / or a solution. According to a preferred embodiment, the polymer solutions are preferred for the cationic polymers and the emulsions are preferred for the amphoteric and nonionic polymers. Advantageously, the oil length of the emulsion of the alkyd polymer is between 10 and 70%, preferably between 20 and 50%, more preferably still between 30 and 40%. The present inventors have found a better ability to isolate stains when using cationic or amphoteric polymers in the form of an emulsion, rather than in the form of a dispersion. This ability to isolate stains is even better when using cationic or amphoteric polymers in the form of a solution.

Within the meaning of the invention, the cationic, amphoteric or nonionic nature of the polymer is that of the polymer before it is added to the composition. Thus, the composition comprises at least one cationic or amphoteric film-forming polymer and at least one nonionic film-forming polymer in which the dry weight ratio of cationic or amphoteric polymer (s) relative to the dry weight of the ) non-ionic polymer (s) is between 20/80 and 80/20. Such a composition comprises active or free cationic groups so that they are capable of forming ionic bonds with anionic compounds, in particular spots and more particularly spots of tannins, red food coloring and soot. The spots are generally anionic in nature. The composition advantageously has a capacity for isolating or blocking stains, in particular soot stains, tannins and red food coloring such as AE _ab <1.0, preferably <0.5, more preferably still <0.3.

In addition to polymers and water, the aqueous composition can also comprise other compounds such as in particular one or more pigments, dispersants, wetting agents, anti-foaming agents, fillers, surfactants, opacifiers, thickeners, d agent , coalescing agents, biocides, antifreeze, antioxidants. According to an advantageous embodiment, more than 70% by dry weight, preferably more than 80% by dry weight, more preferably more than 90% by dry weight or even more than 95 or even 98% by dry weight, of the total compounds other that said polymers are of (i) non-ionic or cationic nature when at least one cationic polymer is present or (ii) non-ionic when at least one amphoteric polymer is present in the composition.

By "non-ionic compound" means a compound which does not contain a filler under the conditions of the composition. By “cationic compound” is meant a compound positively charged under the conditions of the composition. To adjust the rheological profile of the composition, at least one thickener can be added to the composition. It can be a nonionic thickener chosen from polyurethanes such as Coapur 6050 (Coatex); Coapur 3025 (Coatex); Coapur 3020 (Coatex); Coapur 2025 (Coatex); Coapur 975 W (Coatex); Coapur 830 W (Coatex); Coapur 817 W (Coatex); Coapur 520 W (Coatex); Coapur XS 71 (Coatex); Coapur XS 22 (Coatex); Coapur XS 83 (Coatex); Coapur 975 W (Coatex); Rheovis PU 1185 (BASF); Rheovis PU 1191 (BASF); Rheovis PU 1214 (BASF); Rheovis PU 1215 (BASF); Rheovis PU 1190 (BASF); Rheovis PU 1280 (BASF); Rheovis PU 1270 (BASF); Rheovis PU 1251 (BASF); Rheovis PU 1190 (BASF); Rheovis PU 1291 (BASF); Rheovis PU 1250 NC (BASF); Additol VXW 6360 (Allnex); Aquaflow NHS-300 E (Ahsland); Aquaflow NHS 360 (Ashland); Aquaflow NLS 210 (Ashland); Borchi Gel L 76 (OMG Borchers GmbH); Borchi Gel LW 44 (OMG Borchers GmbH); Borchi Gel PW 25 (OMG Borchers GmbH); Rheolate FX 1080 (Elementis Specialties); Rheolate 299 (Elementis Specialties); Rheolate 266 (Elementis Specialties); Rheolate 212 (Elementis Specialties); Rheolate 678 (Elementis Specialties); Viscolam PS 166 (Lamberti); Viscolam PS 167 (Lamberti); Viscolam PS 202 (Lamberti), taken alone or in combination. Preferably, a cellulose ether or a derivative thereof can be used. Such a cellulose ether can be chosen from Natrosol 250 Hydroxyethylcellulose (Ashland); Natrosol Plus 330 PA (Ashland); Natrosol Plus 330 HMHEC (Ashland); Natrosol HE 10K (Ashland); Natrosol HE 3KB (Ashland); Tylose MB 10008 P4 (SE Tylose GmbH & Co. KG); Tylose MH 15002 P6 (SE Tylose GmbH & Co. KG); Tylose MH 50 G4 (SE Tylose GmbH & Co. KG); Tylose MH 30000 YP4 (SE Tylose GmbH & Co. KG); Tylose H 15000 YP2 (SE Tylose GmbH & Co, KG); Tylose 30,000 YP2 (SE Tylose GmbH 8c Co. KG); Tylose 10015 P4 (SE Tylose GmbH & Co. KG); Tylose MH 6000 YP4 (SE Tylose GmbH & Co. KG); Tylose H 10000 NG4 (SE Tylose GmbH & Co. KG); Tylose HS 1000 YP2 (SE Tylose GmbH & Co. KG); Tylose HS 6000 YP2 (SE Tylose GmbH & Co. KG) taken alone or in combination.

The thickeners are advantageously chosen from cellulose ethers to obtain a viscosity which prevents sedimentation of the denser particles, or from associative thickeners of the polyurethane type to refine the rheology of the composition. For this, we use combinations of Newtonian and / or pseudo plastic thickeners. The inventor has demonstrated that the use of Natrosol Plus 330 PA or Natrosol Plus 330 HMHEC makes it possible to minimize splashing during the roller application process, contrary to what has been demonstrated with the grades of Tylose or with Natrosol HE 10K. With the combination of Viscolam PS202 (Newtonian) and Viscolam PS 167 (pseudoplastic) or the combination of Coapur 3025 (Newtonian) and Coapur 6050 (pseudoplastic), the Brookfield viscosity and HERE can be refined. Instead of Coapur 3025, Coapur 2025 or Coapur XS 22 can be used. Instead of Coapur 6050, Coapur XS 83 can be used, for example. The inventor has found that different combinations of thickeners can be used. be used to adjust the desired rheological profile.

The composition may also comprise one or more pigments. It can be a pigment such as titanium dioxide. Such a nonionic pigment does not affect the use properties of the composition. It may in particular be Tiona 121 (Cristal Global); Tiona 595 (Cristal Global); Tiona 113 (Cristal Global); RC 823 (Cinkarna); RC 833 (Cinkarna); RC 813 (Cinkarna); Ti-Pure R-900 (Chemours); Ti-Pure R-901 (Chemours); Ti-Pure R-706 (Chemours); Ti-Pure R-746 (Chemours); Tioxide TR-92 (Venator); NTR-606 (Ningbo Xinfu Titanium Dioxide Co., Ltd.); Billions BLR-895 (Lomon Billions); Billions BLR-698 (Lomon Billions); Billions BLR-699 (Lomon Billions); Billions BLR-896 (Lomon Billions); Pretiox RGU (Precheza) or Pretiox RGZW (Precheza), taken alone or in combination. The production of TiO ₂ uses either a sulphate process or a chloride process. In general, the different TiO ₂ can be used. However, the TiO ₂ obtained from the chloride process makes it possible to obtain higher whiteness than when a TiO ₂ obtained from the sulfate process is used in equal quantity. Thus, Tiona 595, Tiona 113 or Ti-Pure R-706 (chloride process) allow obtaining a composition with whiter properties than RC 823, NTR-606 or Billions BLR-699 (sulfate process). The composition therefore preferably comprises at least one TiO ₂ obtained from the chloride process, preferably at least one TiO ₂ chosen from Tiona 595, Tiona 113 or Ti-Pure R-706.

The composition may further comprise one or more fillers. The fillers can be chosen from natural or calcined kaolins; barytes; calcined or non-calcined combinations of corpuscular silica and lamellar kaolinite; talcs and mica. According to a preferred embodiment in which the composition preferably comprises at least one cationic polymer, said composition comprises less than 30% by weight of calcium carbonates relative to the total weight of the wet composition; preferably less than 25% by weight relative to the total weight of the wet composition and even less than 15% by weight relative to the total weight of the wet composition. According to a preferred embodiment, when the composition comprises at least one cationic polymer, said composition is free of calcium carbonate. By "free" means a composition containing less than 5% by weight of dry extract, preferably less than 2%, more preferably less than 0.5% by weight relative to the total weight of the dry extract of the composition. The use of calcium carbonates leads in fact to the coagulation of certain binders based on cationic polymers which particularly affects the insulating properties of stains. Such a property is particularly strongly impacted during the transition from the acid zone (less than 7) to the basic zone (greater than 7). A basic pH favors the solubilization of anionic spots. According to an advantageous embodiment, the composition has a pH <7, more preferably between 2 and 7, more preferably still between 4 and 6.5.

The charges can be chosen from Dorkafill Cl, Dorkafill H and Dorkafill Pro_Void (Gebrüder Dorfner GmbH & Co. Kaolin- und Kristallquarzsand-Werke KG); Silfit Z 91 (Hoffmann Minerais); Aktifit AM (Hoffmann Minerais); Aktifit PF 111 (Hoffmann Minerais); Sillitin Z 68 (Hoffmann Minerais); Aktisil AM (Hoffmann Minerais); Optimat 2550 (Imerys); Optimal 3060 (Imerys); Optimat 2040 (Imerys); Kaolin - Special (Ores i Derivats); Kaolin - Supreme (Ores i Derivats); Kaolin - Μ (Ores i Derivats); Kaolin - A (Ores i Derivats); Aspanger Mica TF (Aspanger); Aspanger Mica TG (Aspanger); Aspanger Mica 900 (Aspanger); Aspanger Mica TM (Aspanger); Burgess Iceberg (Burgess Pigment Companz); Optigloss (Imerys); Polwhite B (Imerys); Opacity (Imerys); PoleStar200P (Imerys); PoleStar400 (Imerys); Kaolin (Provençale, SA); Speswhite (Lehvoss Group); Luzenac 10M2 (Imerys); Fintale M03 (Mondo Minerais); Fintale M50 (Mondo Minerais); Minex S-10 (Sibelco); Minex S-7 (Sibelco); Minex S-4 (Sibelco); Steamat (Imerys); Steabright (Imerys); Plastorit 000 (Imerys); and others. Between the calcium carbonates, one can choose between Omyacarb Extra GU (Omya); Omyacarb Extra CL (Omya); Omyacarb 2 Extra CL (Omya); Omyacarb 5 Extra CL (Omya); Criscal 1 (Provençale); Criscal 2 (Provençale); Criscal 5 (Provençale); Criscal 10 (Provençale); Mikhart MU08 (Provençale); Mikhart MU12 (Provençale); Mikhart 1 (Provençale); Mikhart 2 (Provençale); Mikhart 5 (Provençale); Mikhart 10 (Provençale); Mikhart SPL (Provençale); Calprec PA (Calcinor); Calprec PR (Calcinor), taken alone or in combination. The distribution of particle sizes and oil intakes of the different charges is taken into account by the formulator to adjust the performance of the product. It is known that the finer particles can be used as diluents for titanium dioxide, a fact which will help increase the opacity of the coating. Likewise, coarser particles will contribute to the reduction in gloss. In the case of finer particles which can improve opacity, there are in particular Silfi Z 91, Aktifit AM, Aktifit PF 111, Sillitin Z 68; Aktisil AM, Dorkafill Cl, Opacilite, PoleStar 200P, Omyacarb Extra CL; Calprec PA; Mikhart MU08. For fillers which help reduce gloss, the inventor has obtained good results with the products Dorkafill Pro_Void, Steamat and Optimat 2550, Mikhart SPL.

The composition may also comprise one or more wetting agents or dispersants chosen from Borchi Gen 1252 (OMG Borchers GmbH); Borchi Gen DFN (OMG Borchers GmbH); Additol VXW 6208 (Allnex); Edaplan 490 (Munzing); Metolat 355 (Munzing); Metolat 388 (Munzing); Edaplan 397 (Munzing); Disperbyk-2012 (BYK Chemie); Disperbyk190 (BYK Chemie); Disperbyk-192 (BYK Chemie); Disperbyk-187 (BYK Chemie); Disperbyk-187 (BYK Chemie); Disperbyk-102 (BYK Chemie); Syntrho-Pon 9 TDK (Synthron); Disperbyk-2096 (BYK Chemie); Disperbyk-191 (BYK Chemie); Nuosperse FN 211 (Elementis Specialties); Tego Dispers 750 W (Evonik); Tego Dispers 650 (Evonik); Tego Dispers 662C (Evonik), taken alone or in combination. The choice among these dispersing agents is made in particular on the basis of the compatibility of each with the film-forming polymers of the composition. The inventor obtained good performance with Disperbyk-190 with most of the polymer combinations of the composition. Borchi Gen DFN is more suitable for compositions comprising WorléeCryl 7712 H because the viscosity does not increase over time as occurs with Disperbyk-190.

The composition may also comprise one or more anti-foaming agents chosen from Foamaster MO 2111 (BASF); Foamaster MO 2134 (BASF); Foamaster MO 2192 (BASF); BYK 030 (BYK Chemie); BYK-024 (BYK Chemie); BYK-022 (BYK Chemie); BYK-025 (BYK Chemie); BYK-028 (BYK Chemie); BYK-1610 (BYK Chemie); BYK-1615 (BYK Chemie); BYK 1723 (BYK Chemie); BYK-1724 (BYK Chemie); BYK-1611 (BYK Chemie); BYK-1640 ((BYK Chemie); BYK-012 (BYK Chemie), taken alone or in combination. For good performance during the manufacturing process, the inventor obtained good results with Foamaster MO 2134 which avoids the presence of in the coating. According to a preferred embodiment, the composition comprises Foamster MO 2134 in combination with at least one of the following compounds: BYK-024, BYK-022 or BYK-028. Combined with Foamster MO 2134 and taken alone or in combination, these compounds make it possible to obtain a composition which does not have surface defects once applied.

According to an advantageous embodiment, the composition contains less than 10% by weight of surfactants relative to the total weight of the wet composition, preferably less than 5%, more preferably less than 2% or even less than 0.5 % by weight relative to the total weight of the wet composition.

The high shear viscosity, or ICI viscosity, is measured at 10,000 s ^-1 according to ISO 2884-1: 1999 (Paints and varnishes - Determination of viscosity using rotary viscometers - Part 1: Cone viscometer and plate operating at high shear speed gradient). Viscosity is an important characteristic of the final composition in order to allow good application of the composition on the support. Too high ICI viscosity makes it difficult to apply with a roller, brush or paintbrush, and may induce the deposition of a film that is too thick or even cause sagging during application. Conversely, an ICI viscosity that is too low makes application easy, but the amount of composition d deposited is generally not sufficient, the thickness of the film then being too small to achieve the desired properties. For example, the opacity may be insufficient. In a preferred embodiment, the viscosity ICI is between 0.5 and 5.0, preferably between 1.0 and 4.0, more preferably between 1.5 and 3.5 or even between 1.5 and 3. The ICI viscosity can be modulated through the use of Newtonian type thickeners. Newtonian thickeners are thickeners allowing a given viscosity to be obtained which does not vary as a function of the shear force applied. According to one embodiment, the composition comprises at least one of the following thickeners: Viscolam PS202 or Coapur 3025.

The low shear viscosity is measured in the context of the present innovation at less than 10 s ^-1 according to ISO 2555: 1989 (Plastics - Resins in the liquid state or in emulsions or dispersions - Determination of the viscosity apparent by the Brookfield Method). This is an important characteristic to guarantee the stability of the final composition in the pot, to avoid any sedimentation. To avoid sedimentation, the low shear viscosity is modulated using thickening agents. The viscosity at low shear also has a strong influence on the behavior of the coating of the composition at the time when it is deposited on the support. Low viscosity at low shear will cause sagging. On the other hand, a very high viscosity at low shear will make it difficult to spread the composition and the final appearance of the film will not be smooth. According to one embodiment, the composition comprises at least one of the following thickeners: Natrosol Plus 330 PA and Natrosol Plus 330 HMHEC.

The viscosity at medium shear is measured between 10 s ^-1 and 1000 s ^-1 according to ISO 2555: 1989 (Plastics - Resins in the liquid state or in emulsions or dispersions - Determination of the apparent viscosity according to the Process Brookfield). The modulation of the viscosity at medium shear influences the quantity of composition taken from the container. It therefore influences the amount of composition which will then be available on the roller or the brush during the application process until a new load of the applicator is necessary. This medium shear viscosity is commonly known under the term Stormer viscosity or Brookfield viscosity. In the context of the present invention, the inventor has identified several thickeners mentioned above allowing mainly the development of viscosities at low and medium shear. Thus, according to a preferred embodiment, the composition therefore comprises Coapur 6050 and / or Viscolan PS 167.

According to a preferred embodiment, the viscosity of the composition is between between 2,000 cP and 40,000 cP, preferably between 8,000 cP and 32,000 cP; more preferably between 14,000 cP and 28,000 cP or even between 17,000 cP and 26,000 cP.

The opacity is determined according to ISO standard 6504-3: 2006 "Paints and varnishes - Determination of masking power - Part 3: Determination of the contrast ratio of clear paints at a determined surface yield".

The wet opacity is mainly modulated by the pigments present in the composition. These pigments have a significantly higher refractive index than all of the other compounds in the composition. Wet opacity can be important during the application process for some coating applicators. The dry opacity is greater than a 98.5% contrast ratio at 200 microns wet according to ISO 6504-3: 2006.

According to one embodiment, the composition comprises between 10 and 25% by weight of titanium dioxide (TiO ₂ ) relative to the total weight of these compounds in the wet, more preferably between 16 and 25%>; and more preferably still between 20 and 25%. Such a content makes it possible to achieve good opacity.

According to another embodiment, the composition comprises T1O2 in combination with at least one diluent pigment of TiO ₂ . In this embodiment, the composition advantageously comprises between 5 and 20% by weight of titanium dioxide TiO ₂ relative to the total wet weight, more preferably between 10 and 20%; and more preferably still between 12 and 17% or even strictly less than 16%.

The diluting pigments of titanium dioxide are particles, generally mineral, which have the function of separating the particles of titanium dioxide in order to facilitate the refraction of light by said particles of TiO ₂ . According to an advantageous embodiment, the diluent pigments of titanium dioxide are present in an amount of 5 to 50% by weight relative to the total wet weight of TIO2, more preferably between 10 and 25% and more preferably still between 15 and 25 %.

The coatings obtained from the composition have good resistance to wet abrasion. Thus, the compositions can be classified in class 3, preferably in class 2 and more preferably still in class 1 according to standard EN 13300.

Advantageously, the composition makes it possible to obtain a coating, in particular a paint or a varnish, particularly intended to be applied to facades and / or walls of buildings.

Other objects and advantages of the invention will appear on reading the particular embodiments below exemplified and given by way of nonlimiting examples.

EXAMPLES The basic formulation of the exemplified compositions is indicated in Table 1 (% by wet weight). Formulation A comprises an amphoteric film-forming polymer and a nonionic film-forming polymer in combination. Formulation B comprises a cationic film-forming polymer and a nonionic film-forming polymer. The concentration of film-forming polymers was adjusted to obtain a given dry extract, detailed in each of the examples below. The Brookfield viscosity is between 17,000 and 26,000 cP, the ICI viscosity between 1.5 and 3 and the pH between 4 and 6.5.

The compositions were prepared as detailed below:

- step 1: preparation of a dispersion of pigments and composition charges detailed in table 1;

- step 2: dilution in the previous preparation of the polymers, coalescing and equalizing agents and addition of water;

- step 3: correction of the viscosity.

Steps Raw materials AT B Step 1. Water 15 15 Preparation of the biocide 0.2 0.2

dispersion of pigments and fillers Anti-foam 0.3 0.5 Dispersing agent and surfactant 0.5 0.5 Titanium dioxide 15 15 Kaolin 18 25 Calcium carbonate 15 0 Fillers other than calcium carbonate 5 20 Anti-foam 0.2 0.2 Water 0.5 0.5 Dilution step 2: the opposite compounds are added in order to the dispersion of step 1 Film-forming polymer 1 PF Al PFB1 Film-forming polymer 2 HFP2 PFB2 Coalescing agent 1 1 Water tock tock Equalization agent 0.1 0.1 Step 3 to correct the viscosity Water tav tav Nonionic thickener tav tav

tav: quantity necessary to adjust the Brookfield viscosity and ICI; tac: amount needed to adjust the concentration of the final formulation to 100

Table 1

Example 1 Coating compositions of formulation A according to Table 1 above were prepared. These compositions comprise an amphoteric polymer and a nonionic polymer, the total content of polymers in the compositions being 12% by weight relative to the total weight of the dry extract. The amphoteric polymer (PFA1) is an amphoteric modified alkyd emulsion with an oil length of about 35% and a dry extract of between 42 and 45% by weight manufactured by ASK Chemicals GmbH (Necowel 4300). The non-ionic polymer (PFA2) is an aqueous emulsion of a copolymer based on vinyl acetate and vinyl ester of versatic acid having a dry extract of between 53 and 57% (Polidisp 7215).

The respective ratio between the two polymers PFA1 and PFA2 (wet weight ratio) varied according to the compositions exemplified as indicated in Table 2 below.

The resistance to stains and to wet abrasion of each of the test compositions was evaluated according to the method indicated in the description. The results are presented in Table 2 below.

compositions 1 2 3 4 5 Amphoteric polymer (PFA1) in% by weight on the total formula 90 70 50 30 10 Non-ionic polymer (PFA2) in% by weight on the total formula 10 30 50 70 90 PH 5.5 6.0 6.2 6.4 6.9 Stain isolation (AE _ab average 16 stains) 0.1 0.1 0.2 3.0 4.3 Soot spot insulation (AE _ab ) 0.05 0.1 0.3 2.1 8 Food coloring stain isolation (AE _ab ) 0.1 0.1 0.3 2 3 Resistance to humic abrasion (loss of thickness in μm) 25 10 3 2 1

Table 2 Composition 1 has the best performance in terms of stain insulation but poor resistance to wet abrasion. Adding a nonionic polymer in combination with an amphoteric polymer improves the wet abrasion resistance of the composition. However, when the nonionic polymer is present in large quantity compared to the amphoteric polymer, the composition has a lower capacity for stain isolation. For the field of wall coverings, compositions 2 and 3 are preferred. Composition 3 is particularly preferred.

Example 2 Coating compositions of formulation B according to Table 1 were prepared. These compositions comprise a cationic polymer and a nonionic polymer, the total content of polymers in the compositions being 12% by weight relative to the total weight of the dry extract. The cationic polymer (PFB1) is a pure solution of a film-forming acrylic polymer having a dry extract of between 28 and 32% by weight (WorléeCryl 8721). The nonionic polymer (PFB2) is an aqueous emulsion of a copolymer based on vinyl acetate and vinyl ester of versatic acid having a dry extract of between 53 and 57% by weight (Polidisp 7215).

The respective ratio between the two polymers PFB1 and PFB2 (percentage by wet weight) varied according to the compositions exemplified as indicated in Table 3 below.

The stain resistance, the adhesion and the opening time of each of the test compositions were evaluated according to the method indicated in the description. The results are presented in Table 3 below.

compositions 6 7 8 9 10 Cationic polymer (CB1) in% by weight on the total formula 90 70 50 30 10 Non-ionic polymer (NIB1) in% by weight on the total formula 10 30 50 70 90 pH 4.3 4.5 4.8 5.5 6.3 Stain isolation (average AE of 16 spots) 0.1 0.1 0.2 2.3 3.9 Soot stain insulation (AE) 0.1 0.1 0.3 2.1 8.0 Food coloring stain isolation (AE) 0.1 0.1 0.3 1.0 3.0 membership 1 1 1 1 3 Opening times 5 7 10 10 10

Table 3 Composition 6 has the best performance in terms of stain isolation but the opening time of this composition is not long enough for the technical field of compositions for wallcoverings. Adding a nonionic polymer in combination with a cationic polymer improves the opening time of the composition. However, when the nonionic polymer is present in a large amount compared to the cationic polymer, the composition has a lower capacity for stain isolation and reduced adhesion properties. For the field of wall coverings, compositions 7 and 8 are preferred.

Claims (11)

claims 1. Aqueous composition for coating comprising at least one cationic or amphoteric film-forming polymer and at least one nonionic film-forming polymer in which the dry weight ratio of cationic or amphoteric polymer (s) relative to dry weight non-ionic polymer (s) is between 20/80 and 80/20. 2. Composition according to claim 1, in which the cationic film-forming polymer is chosen from acrylics, styrene-acrylics, epoxy esters, alkyds and modified alkyds, polyurethanes (PU), polyurethane and polycarbonate copolymers, esters vinyl and vinyl ester copolymers taken alone or in combination. 3. Composition according to claim 1 in which the amphoteric polymer is chosen from acrylic polymers or copolymers or alkyds taken alone or in combination. 4. Composition according to any one of the preceding claims, in which the nonionic polymer is chosen from polyurethanes (PU), vinyl polymers or copolymers, in particular copolymers based on vinyl acetate and vinyl acid ester. versatic, polymers based on vinyl acetate and vinyl neodecanoate or polymers based on vinyl acetate, ethylene and acrylic, taken alone or in combination. 5. Composition according to any one of the preceding claims, in which the dry weight ratio of cationic or amphoteric polymer (s) relative to the dry weight of the non-ionic polymer (s) ) is preferably between 25/75 and 75/25, more preferably between 30/70 and 70/30, more preferably still between 45/55 and 55/45 or even between 48/52 and 52/48. 6. Composition according to any one of the preceding claims, in which the dry weight of cationic or amphoteric polymer (s) is greater than the dry weight of the non-ionic polymer (s). 7. Composition according to claim 1, in which more than 70% by dry weight, preferably more than 80% by dry weight, more preferably still more than 90% by dry weight, total compounds other than said polymers are of nature (i ) nonionic or cationic when at least one cationic polymer is present or (ii) nonionic when at least one amphoteric polymer is present. 8. Composition according to any one of the preceding claims, in which the pH is less than or equal to 7, preferably between 2 and 7, more preferably between 4 and 6.5. 9. Composition according to any one of the preceding claims, in which at least one cationic or amphoteric polymer has been added in the form of an emulsion or a solution. 10. Coating obtained from the composition according to any one of the preceding claims. 11. Use of the composition according to any one of claims 1 to 9 for the manufacture of a coating, preferably a paint or a varnish.