MXPA98000559A - Aqueous mixtures of polymers dispersed coloidalme - Google Patents

Abstract

The present invention relates to: The invention pertains to aqueous mixtures of colloidally dispersed polymers for use in the manufacture of organic coatings, which are hard and ductile at room temperature, coatings which remain rigid and elastic at temperatures well above the temperature of film formation or drying. In particular, the invention relates to specific combinations or thermoplastic mixtures of polymers of very high molecular weights. Such blends produce uniform coatings, essentially free of cracks or crevices when conventionally dried under atmospheric pressure. Such mixtures are capable of developing the desired balance of properties without conventional amounts of volatile organic coalescence adjuvants and without the need for chemical curing.

Description

AQUEOUS MIXES OF COLORELY DISPERSED POLYMERS FIELD OF INVENTION This invention pertains to aqueous mixtures of colloidally dispersed polymers for use in the manufacture of organic coatings which are hard and ductile at room temperature, and which remain rigid and elastic at temperatures well above their film-forming or drying temperature. In particular, the invention relates to mixtures of high molecular weight thermoplastic polymers, which are able to develop these mechanical properties without conventional amounts of volatile organic coalescence aids and without the need for chemical curing.

BACKGROUND OF THE INVENTION The operation of many coatings such as paints are ordered to mechanical properties of one or more organic polymers that serve either as coatings per se or as binders for other components of the coating, such as pigments and fillers. For use in automotive paints, it is desirable that such polymers be hard at temperature REF: 26664 environment, as illustrated, for example, by Knoop hardness index (KHN) greater than about 5 MPa (L. Dillinger, "Hardness Testing", LECO Corp., 3000 Lakeview Ave., St. Joseph, MI; and ASTM D 1474-68). It is also desirable that such polymers retain a certain degree of rigidity and elasticity at temperatures of use of 60 ° C or greater, for example, that exhibit a Young's modulus (E) greater than 10 MPa. Amorphous polymers exhibit such properties only when their glass transition temperature Tq is equal to the higher use temperature. The present invention relates to a new class of coating formulations to achieve those objectives. Coatings and films are commonly characterized as either brittle or ductile depending on the way in which they fail under tensile loads (IM Ward, Mechanical Properties of Solid Polymers, Chap 12, John Wiley &Sons, London, 1971) . Fragility failure occurs at relatively small efforts, for example < 20%, following an increase or otonic in the load. In contrast, ductile failure occurs at higher elongations, following a peak in the load / extension curve that is indicative of elongation. Highly crosslinked, thermoset polymeric resins are generally brittle, often with elongations of < 10%, while linear thermoplastic polymers, of high molecular weight, they typically exhibit a change in the failure mode with temperature. At temperatures below the Tg, most thermoplastics are brittle, but experience a ductile brittle failure transition as the temperature increases, and the temperature of this transition generally increases with the increase in the stress rate. Ductility (especially elongations of> 10%) is a desirable property for coatings on flexible substrates and also for coatings, such as automotive paints, on metals, because the ductility contributes to the coating's ability to serve impacting impacts or bend the substrate without causing cracks or crevices or detachment. The present invention provides means for preparing coatings with a good balance of hardness, ductility, and stiffness, from very high molecular weight polymers, without the need for conventional high amounts of volatile organic components and without the need for chemical cure. Aqueous colloidal dispersions of polymers are increasingly important in the paint industry because the coating constituents can be obtained in relatively concentrated form (> 20%), at moderate viscosities, and with little or no need for organic solvents volatile, which constitute undesirable side products in the application of paints. However, drying such dispersions to form uniform, crack-free or crevice-free coatings is subject to certain well-known limitations. Such dispersions have been characterized, in each case, by a minimum film formation temperature, MFT, which is typically a few degrees below the glass transition temperature Tq of the colloidal polymer particles (See for example, G. Allyn, Film Forming Compositions, RR Myers &; J.S. Long, Ed., Marcel Dekker, N.Y. 1967). The degree to which the polymer in a dispersion can be plasticized by other components of the dispersion, the MFT can be reduced accordingly. If a dispersion dries at a temperature (T) lower than the MFT, a multitude of microscopic cracks or fissures, called "cracks or silent fissures", which destroy the integrity of the coating, tend to develop at the end of the drying process. During drying, the actual temperature of an aqueous dispersion can be limited, by cooling by evaporation, to a much lower value than the temperature of the surrounding atmosphere. Thus, regardless of the furnace temperature, the coating temperatures typically should not exceed about 35 ° C, under atmospheric pressure, until all the water has been lost (F. Dobler et al., J. Coil, Poly. Sci., 152, 12 (1992)). This means that dispersions with MFT > 35 ° C are generally not useful for coating applications. But polymers not plasticized with MFT < 35 ° C generally does not provide adequate mechanical properties, including hardness at higher usage temperatures. Commonly, two strategies have been employed to fill this gap between film formation requirements and the requirements of hard coatings with high temperatures of use. First, volatile organic plasticizers (often described as coalescing adjuvants or film formers) have been added to the dispersion. They dissolve in the polymer and lower their Tg during drying, but finally they volatilize at a later stage of drying, leaving the final resin with a higher Tq. This strategy, however, conflicts with economic and environmental motivations to limit the amount of volatile organic content (VOC) content in coating formulations. A second strategy has been to formulate the dispersion with a low molecular weight thermosetting resin which, before curing, has a Ta low enough to provide film formation. After it is dried, it is cured at elevated temperatures, which results in crosslinking reactions and extension of chain, increase of Tq and establishment of the mechanical properties finally desired. In recent years, it has been found that coatings prepared from mixtures of aqueous dispersions of polymeric colloids that form films and that do not form films can be prepared with little or no need for a coalescence aid. Friel (EP 0 466 409 A1, April 7, 1991) has shown that mixtures of dispersions of a "mild emulsion polymer" with a Tq < 20 ° C, at 20 to 60% by weight, in combination with a second "hard emulsion polymer" with Tq > 20 ° C exhibits MFT = 9.35 ° C, without the need for a coalescence adjuvant. All the cited examples, however, exhibited KHN purities < 2.7 MPa. Snyder (U.S. Patent No. 5,344,675, September 6, 1994; U.S. Patent No. 5,308,890, May 3, 1994) has shown that blends of a film-forming dispersion of a "multi-stage" latex polymer and a second non-film-forming dispersion coatings can be used without the need for a coalescence aid. . Snyder specifies that each latex particle in the "multi-stage" component may contain between 50 and 95% by weight of a polymer with Tq < 50 ° C and a second polymer of Tq. A certain balance was achieved between the hardness, impact resistance and flexibility of the covering. The * 890 patent also states in column 3, lines 25-30 that "a comparable balance of those properties can not be obtained by the use of other types of systems, such as, for example, a random copolymer, simple mixtures of polymers in conventional emulsion, a single type of multi-stage polymer. " Among the examples cited for coatings made without a coalescence aid, three have KHN > 5.5 MPa, but those are characterized by an inverted impact resistance < 2 inch-pounds and a flexibility that corresponds to the flexibility of the 1/2"mandrel. (According to ASTM D 1737-62, a 1/2" mandrel bending equals approximately the elongation per interaction of 6.8%) . They cite additional examples with a KHN of between 4.0 and 5.5 MPa, but with an impact resistance ranging from 4 to 60 inch-pounds and a mandrel flexibility of 1/2"to 3/16".

BRIEF DESCRIPTION OF THE INVENTION The invention pertains to an aqueous dispersion comprising a mixture of polymeric components, each in the form of colloidal particles having average hydrodynamic diameters less than about 1000 nm and preferably less than about 200 n, the polymer components comprise: a first polymer component comprising from about 20% to about 50% by volume of the total polymeric content and exhibiting a measured Tq (I) greater than or equal to 9 ° C; a second polymeric component comprising from about 45% to about 80% by volume of the total polymeric content and exhibiting a measured Ta (II) of less than 49 ° C and greater than 24 ° C; and a third polymer component comprising 0% to about 35% by volume of the total polymeric content and exhibiting a measured Tq (III) of less than 24 β C; the sum of the three polymeric components is 100% in volume; wherein the first, second and third polymer components each have an M * greater than about 80,000 and are mutually adherent; and wherein the aqueous dispersion has a volatile organic content (VOC) content of less than about 20% by weight of the total polymer content. The invention also belongs to an aqueous dispersion which, after being dried at atmospheric pressure at temperatures greater than or equal to 35 ° C and annealed to temperatures greater than Tq (I), form a continuous, homogeneous coating, which is characterized by a balance of hardness, ductility and rigidity at temperatures higher than Tq (II), properties which are represented, respectively, by a KHN = approximately 3 MPa at 24 ° C, preferably by KHN = 5 MPa at 24 ° C, tensile elongations greater than or equal to about 20%, and retained storage modulus, E '(1Hz) > about 10 MPa at T - [T ,, (I) + T, (II)] / 2 and where the properties are achieved without requiring, during drying, or annealing, the cross-linking or branching of the molecular chains of the polymer components to increase the sensitivity of the molecular weights to the polymeric components. In addition to the polymer, the dispersion mixtures of the present invention may contain other constituents, including pigments, salts, surfactants, stabilizers or UV inhibitors. The invention further pertains to a clear coat or color coating composition comprising from about 10% by weight to about 50% by weight polymeric binder solids, the binder solids comprise from about 30% by weight to about 100% by weight. weight of the aqueous dispersion described above. Such coating compositions, when dried, are capable of forming dense, crack-free or crevice-free films for use on automotive or other substrates, DETAILED DESCRIPTION OF THE INVENTION The dispersion mixtures of the present invention have utility in the production of hard organic coatings such as paints. For such applications, the dispersion mixture can be mixed with other functional components such as pigments, fillers, or reagents to modify the rheology, etc., as will be understood by those skilled in the art. Such additional materials may, either, increase or compromise certain properties of the final coating. It should, therefore, be understood that those physical properties exemplified by, and claimed for, the coatings derived from the polymer dispersion blends of the present invention, which essentially contain no other dispersed materials or solids, represent a starting point from which the inclusion of other material may result in additional improvement or mitigation, depending on the total properties of the final composition. The dispersion mixtures claimed in this invention form dense organic coatings, essentially free of cracks or crevices, hard, ductile, when dried at atmospheric pressure and temperature of about 40 ° C and subsequently annealed at temperatures higher than the highest Tq, namely Tq (I). The coatings remain rigid and elastic at temperatures well above the film forming or drying temperature without requiring cure, ie without any chemical bonding reaction to increase the M "or crosslinking of the polymer. An example of a combination of properties that can > achieved from a binary mixture according to the present invention is described in Example 44 (Mixture 50) below. A Type I polymer was mixed with T ", (I) -90 ° C with a Type II polymer of T, (II) -34 ° C, resulting in a Knoop hardness index (KNH) of 12 MPa. , a Young's modulus (E) of 1.7 GPa, an elongation by traction (e * -, *) of 46%, a resistance to impact of 50 inches-pounds (0.434 kg-m, 4.26 joule), a flexibility in mandrel <; 1/8"(0.32 cm), and at a temperature of 62 ° C .. {middle part between the two Tq), a retained storage module (E ') of 0.31 GPa, the mixtures of the present, depending on the particular mode, may or may not include multistage polymer latex particles, such particles are predominantly amorphous, and dispersions of such particles are very commonly prepared directly by free radicals, emulsion polymerization, in water, of unsaturated monomers such as acrylic acid (AA), methacrylic acid (MAA) and their respective esters or amides, including, but not limited to methacrylate butyl (BMA), butyl acrylate (BA), ethyl acrylate (EA), 2-methoxyethyl acrylate (MeOA), 2-ethylhexyl methacrylate (EHMA) and methyl methacrylate (MMA), acrylonitrile, vinyl or vinylidene, vinyl acetate, vinylpyridine, N-vinylpyrrolidone, styrene (Sty), 2-propenoic acid, 2-methyl-1,2- (2-oxo-l-imidazolidon) ethyl ester, etc .; but polymers which have been first polymerized pure or in solution by condensation reactions or by other addition reactions other than those initiated by free radicals can also be prepared by dispersion in water. See J. C. Padget, J. Coa tings Tech. , 66, p 89 (1994) and D. C. Blackley, Emulsion Polymerization, Applied Science Publ. Ltd., London 1975. For the dispersions of the invention to be stable with respect to settling and / or flocculation, colloidal particles are typically established by some combination of ionic functional groups on the surface of the polymer and / or surfactants absorbed onto their surface. surface and / or by the low ionic strength of the aqueous phase.

The dispersion mixtures of this invention are further characterized by the fact that the different polymers in the mixture remain in separate phase after drying and annealing, at temperatures above the glass temperature Tq (I) higher, so that the resulting material exhibits two (or more) vitreous temperatures, for example, with respect to its thermomechanical properties (NG McCrum, BE Read, &G. Williams, Anelastic and Dielectric Effects in Polymeric Solids, Dover Publ., NY, 1991). The mixtures of this invention are further distinguished by the development, during annealing, of mechanically strong interfaces between the different polymer phases making them "mutually adherent". By "mutually adherent" with respect to the polymeric components of a dispersion mixture, it means that, after lamination and annealing of the films made from the polymeric components, it is possible to detach or separate the films along their interface original. As illustrated in the examples, the three types of polymer I, II and III described herein serve different functions in the invention in terms of their film-forming capabilities and their effects on the mechanical properties of a coating made thereof. Colloidal dispersions of Type II and / or III polymers alone are capable of forming dense coatings, free of Cracks when drying at temperatures of > 40 ° C in the absence of any coalescence adjuvant. Type I dispersions can not form such coatings without the addition of some plasticizer as a coalescence adjuvant, because their MFT is otherwise very high. Types I or II can provide coatings that are hard (KHN > 3) at room temperature (24 ° C), because Tq exceeds this temperature. However, in mixtures among the three types of dispersions, it was found that those for which the polymer weight comprises = 50% by weight of Type I can form dense, essentially crack-free films in the absence of, or with lesser amounts of, conventional, one or more adjuvants of organic coalescing agents. Conventional amounts of coalescing agents are typically about 25% by weight of the total polymer content, resulting in a VOC (Content of Volatile Organic Products) relatively higher. In contrast, the present invention comprises less than about 20% VOC, preferably less than 10% VOC, and more preferably less than 5% VOC, as measured by heating a coating or other composition at 105 ° C for 20 minutes and determining the weight of material that was volatilized. See Reference Method 24 EPA (U. S. Environmental Protection Agency) and ASTM D-3960.

In mixtures according to the present invention, the ratio of Type II to Type III polymers can be further adjusted to obtain the desired mechanical properties of the final coating. For example, as illustrated in Example 49 below, when the polymer weight comprises < 40% of Type III, the coating will exhibit a KHN > 3 MPa. The Tq of the components of the mixtures can be achieved with or without the addition of a non-volatile plasticizing agent to those polymers whose intrinsic Tq is greater than those specified. Consequently, the relevant Tq of the components of a mixture are the T-, resulting measured by a DSC of the mixture. Type I polymers have the highest Tq. This determines the maximum temperature at which the coating can exhibit a certain degree of stiffness and elasticity, for example a storage module E '> 0.01 GPa, at a frequency of 1 Hz. The exact magnitude of E 'depends on the weight fraction of the Type I polymer, so that larger fractions provide a larger E'. As illustrated by Example 44 (B-50) later in Table 8, a mixture containing 50% by weight of a Type I polymer can exhibit a value of E 'at temperatures of between Tq (I) and Tq (II) very close to the theoretical maximum value obtainable from an isotropic mixture of the pure components (Z. Hashin &S. Shtrikmann, J. Merch, Phys. Sun, 11, 127 (1963)). The coatings are preferably annealed at a temperature well above the higher Tq namely Tq (I), to obtain the optimum mechanical properties. In the examples described below, annealing was for 20 minutes at 130 ° C. Without annealing, it was found that the dried coatings prepared from dispersion mixtures of the invention were very brittle, as characterized by elongations < 10% and without stretching under tension. It is thought that the effects of annealing involve some combination of the following processes: (1) secondary coalescence of Type I particles, which involves the growth of mutual interfaces and diffusion of chains through those interfaces, (2) relaxation of the efforts elastics within the phase domains of Type II and increase dt. interdiffusion in those domains that comprise a continuous network, and (3) a limited degree of interdiffusion between the phase domains of Type I and Type II that reinforces these heterogeneous interfaces. (See, for example, S. Voyutsky, Autohesion and Adhesion of Hiqh Polymers, Wiley-Interscience, N. Y., 1963). An important aspect of this invention is the discovery that the ductility of the coatings derived from the dispersion mixtures depends in a Critical of the interface between the different phase domains of the polymer. The examples in Tables 6, 7 and 10 show that films prepared from dispersion mixtures containing Types I, II, and III, in the proportions described by the invention, show good ductility. For example, mixtures of P (MMA / BA) of Type I with P (MMA / EA) of Type II in Table 6 exhibit elongation and high elongation characteristics of a strong, ductile material. Table 10 shows similar results for mixtures of P (MMA / BMA) Type I with P (BMA) Type II. For the purposes of this invention, the mutual adhesion between any two polymers, for example, of Types I and II, can be evaluated according to the following test. Independent films, with thicknesses greater than about 20 μm, of each polymer is prepared by a method such as drying the polymer dispersion, molding a film from a solution, or compression molding a film from a powder polymeric dry. The specimens of each film are then laminated together, under pressure (for example, 100 MPa), at a temperature of at least 40 ° C higher than the highest T, represented by Tq (I), for a period of at least 20 minutes. , to create an intimate molecular contact area. This area can be any conventional size, for example, 2 cm by 10 cm. Laminated specimen is left then cool to room temperature (e.g., 24 ° C) and an attempt is made to separate the two components by detaching them along the original interface. When the interfacial strength in such a sheet is less than the cohesive fracture strength of any polymer tested, for example, Type I, Type II or Type III, then it is possible to detach or cleanly separate the two components, so it is said that the sheet fails adhesively. Alternatively, if the mutual adhesive strength is comparable to the cohesive strength of any component then it is not possible to mechanically detach or separate the polymeric films along their original interface. Instead, the sample will typically fail cohesively fracturing or tearing through the thickness of one or both components. The cohesive and adhesive strengths can be characterized quantitatively by the rate of critical energy release, G, as described in Fracture Mechanics of Polymers, by JG Williams, Ellis and Horwood, Ltd., West Sussex, England, 1984. However, for the purposes of the present, the simple qualitative distinction between the cohesive failure and the adhesive failure of those sheets is sufficient to determine whether such pair is mutually adherent or non-adherent. In this way, the mutual adhesion between a given pair of polymers, measured in this way, is an indicator reliable ductility of the coatings and films that can be prepared by drying and annealing the aqueous colloidal dispersions of the same or two polymers, as described in this invention. In particular, when an aqueous dispersion of colloidal polymers of Type I and Type II (or II and III, or I and III), containing less than about 20%, preferably less than 10%, more preferably less of 5%, in content of volatile organic compounds by weight of the total polymeric content, dried and annealed at a temperature of at least 40 ° C higher than the highest Tq for a period of at least 20 minutes, the resulting film may exhibit , at 2 ° C, a tensile failure, which is brittle (for example, with elongations less than 10% without significant elastic deformation) or ductile (for example, with elongations greater than 10%, accompanied by elastic deformation or elongation) . As illustrated by the examples in Tables 7 and 1, the ductile failure was observed in each case when the polymer pairs are mutually adherent, and the brittle failure was observed when they are not mutually adherent. Similarly, Example 55 can be characterized as marginally adherent since the sheets fail by a combination of the adherent and cohesive modes. The corresponding mixtures (Examples 67-70) They exhibit tensile faults that fluctuate from brittle to ductile, depending on the composition of the mixture. The polymer-polymer compatibility plays an important role in the mixtures of this invention. The coatings made from the dispersion mixtures of the invention remain chemically heterogeneous, each polymer component remains in different phase domains, as can be distinguished by methods such as electron microscopy and by various manifestations of vitreous transition temperatures, for example , in dynamic mechanical measurements. This heterogeneity can be the result of the true immiscibility of the polymer components in the thermodynamic sense of the equilibrium phase separation. Or it may be that the polymers are actually thermodynamically immiscible under the process conditions but, in view of their high molecular weights, they remain in segregated phases for kinetic reasons. Thus, for Mw = 80,000 daltons, it could take a long time to achieve diffusion to achieve complete mixing of a mutually compatible pair. However, it should be noted that for high Mw, the vast majority of polymer pairs, even copolymers that differ in the proportion of comonomers, are, in effect, thermodynamically immiscible.

Acrylic polymer pairs exhibiting a strong interface (as exemplified by the cohesive failure of the sheets and ductile bending formation) often contain a common comonomer. It may be that this common structural element imparts a limited degree of thermodynamic compatibility, eg, similar solubility coefficients for the two copolymers, so that a limited degree of interdiffusion can occur that reinforces the interface. The examples in Tables 6, 7 and 10 below illustrate the correlation of ductility with the presence of a common comonomer in both components of a binary mixture. In Table 6 below, the common comonomer is methyl methacrylate, and in Table 10, this is butyl methacrylate. Note that for 50/50 blends in Table 10, only marginal ductility was obtained when the common comonomer comprises only 25% of the Type I component. The coating properties obtained from the dispersion mixtures of the invention, especially in equilibrium of the properties, more especially the combination of ductility with KHN > 5 MPa, represent substantial improvements over the prior art as described by the examples, by Friel, in EP 0 466 409 A1, April 7, 1991, and by Snyder in US Patent Nos. 5,344,675; 5,308,890, which was made reference above. Furthermore, this balance of properties is especially not obvious given that it can be obtained from simple emulsion polymers, not only multilayer polymers, in contradiction to Snyder's teaching. The aqueous colloidal copolymer dispersions of the present invention can be made in a variety of ways known to those skilled in the art. While not wishing to limit the following methods, all dispersions in the following examples were made by standard batch emulsion emulsion polymerization, using sodium dodecylsulfate (SDS, 0.1 to 1.0 mole percent based on monomer) or other material such as it is later identified as surfactant, and initiator of ammonium persulphate (APS). The polymerizations were carried out to completion under monomer-poor conditions at about 33% solids.

EXAMPLES The general procedure for producing the polymers employed in this invention is as follows. All monomers, initiators and surfactants including SDS, are dioctyl sulfosuccinate (DOSS), and the onoammonium salt of nonylphenol ethoxylate sulfate (Ipegal® CO-425), are commercially available (Aldrich Chemical Co., Milwaukee, Wl) and used as received. A cauldron of 2-L resin (4-L for 800 g reactions) equipped with a condenser, viewing funnel, mechanical stirrer and temperature control probe was charged with the water required to produce 33% by weight of solids, less of 100 ml, and SDS. The contents were stirred and heated to 80 ° C until all the SDS was dispersed. The APS was dissolved in 100 ml of water, and 80 ml of this solution was added to the cauldron. All monomers except MAA (if used) were mixed and divided into two equal portions. A portion of the monomers was charged to the addition funnel, and approximately 20 ml was added to the cauldron. The rest was added by dripping for approximately 1/2 hour, maintaining the temperature in the cauldron between 80 and 85 ° C. The MAA (if used in the particular Example) was mixed with the second half of monomer, which was charged to the addition funnel and added slowly for 1 hour, maintaining the temperature in the kettle between 80 and 85 ° C. After the addition, the remaining persulfate solution was added, and the latex was heated for 1 / hour at 85 ° C. The latex was then heated to boiling until no more monomer appeared in the condenser. The latex was then cooled and filtered through a paint scrubber.

The resulting dispersions were stable, cloudy, with Brookfield viscosities ranging from 5 to 10 poise (0.5-1.0 Pa.sec). A 10 g sample of latex was poured into a 5 cm round aluminum container which was then placed in a vacuum oven at 75 ° C, at approximately 400 mm Hg overnight. The solids content, differential scanning calorimetry (DSC) measurements, and gel permeation chromatography (GPC) were made in this dry material, as described below. The reported Tq values are the midpoint temperatures in degrees Celsius of the DSC scans recorded according to ASTM D3418-82. The temperature dependence of the mechanical properties was characterized by DMA, in a commercially available instrument (Model DMA-7 *, Perkin-Elmer, Norwalk, CT). Free-resting film specimens (eg, 0.06 x 4 x 10 mm) were mounted between clamps parallel to a static tension of 20 mN, and subjected to a dynamic sinusoidal stress of 10 mN amplitude at a frequency of 1.0 Hz The storage modulus, E ', was measured when the sample was heated from -20 ° C to 90 ° C at 5 ° C / min. Molecular weights were measured by GPC. The equipment employed consisted of the following. Columns; 2 pl gel 5 μm mixed c, 300 mm x 7.5 mm (Polymer Labs, A herts, MA, part # 1110.6500); Detector: Waters 410 * refractive index detector (Waters, Inc., Mildford, MA); Pump: Waters 590 * (Waters, Inc., Mildford, MA); and Column Heater (Waters, Inc., Mildford, MA). The internal temperature of the refractive index detector was 30 ° C; solvent, tetrahydrofuran (THF), 0.025% butylated hydroxytoluene (BHT) inhibited (Omnisolv); Flow Rate, 1 ml / min; Concentration (lOmg / lOml). The samples were prepared by dissolving overnight with gentle agitation, and then filtering through a 0.5 μm filter (Millipore, Bedford, MA). The hydrodynamic diameters (particle size) of the polymer particles were determined by quasi-elastic scanning in a range of about 50 to 150 nm, using a Brookhaven Instruments BI-90 * 'instrument (Brookhaven Instruments, Brookhaven, NY). See generally Paint and Surface Coatings: Theory and Practice, ed. by R. Lambourne, Ellis Horwood Ltd., West Sussex, England, 1987. pp. 296-299, and The Application of Laser Light Scattering to the Study of Biological Motion, ed. by J.C. Earnshaw and M. W. Steer, Plenum Press, NY, 1983, pp. 53-76. The coatings were prepared by pouring or spraying the dispersion onto flat substrates (glass or metal), drying in a temperature controlled oven at atmospheric pressure (generally at 80 ° C), followed by annealing at a higher temperature higher than Tq (I) (generally 130 ° C). For spray applications, an antifoaming agent such as 2, 3, 7, 9-tetramethyl-5-decin-4,7-diol (Surfynol-104®, Air Products and Chemicals, Inc., Allentown, PA) was added. to the dispersion at less than 2% solids. This had no plasticizing effect or detectable film formation. Film formation was evaluated after drying and after annealing. In particular, the formation of microcracks penetrating the entire coating thickness ("silent cracks") was noted as an unacceptable film formation. The hardness measurements were made on coatings of 0.001 to 0.003"(0.00254 to 0.00762 cm) of thickness on the substrate measured at temperatures between 21 ° C and 24 ° C to the environment by means of a commercially available microindentation instrument (LECO Corp ., St. Joseph, MI, part number M-400-G1.) Films with free standing were prepared from coatings cast on glass plates.The dispersions of these copolymers were generally evaluated from depressions (0.005 to 0.015 inches, 0.0127 to 0.0381 cm) on glass, with subsequent drying in air at 70 ° C for 10 minutes, and annealing at 130 ° C during 20 minutes. The final coating thickness was approximately 0.001 to 0.0025 inches (0.00254 to 0.00635 cm). All film thicknesses were measured with a micrometer. This protocol closely resembles typical drying and curing cycles for thermosetting coatings. The mechanical properties of the binary mixtures were evaluated at room temperature and humidity (for example, 23 ° C, relative humidity or RH of 50%) both for films with free rest (0.0025", 0.00635 cm thick) and for coatings (. 001", 0.00254 cm, thickness) applied on primed steel panels (cold rolled steel with C168 conversion and ED5000 primers, ACT Laboratories, Troy, MI). All samples were first dried at 80 ° C for 5 minutes and annealed at 130 ° C for 20 minutes. The tensile test (Instron, Canton, MA, part number MTAOPR66) was made on specimens of films of 50 to 100 um in thickness (0.002 to 0.004 inches), 6.25 mm (0.25 inches) in width of 2.5 cm (1 inch) long, at an effort velocity of 0.017 / sec at temperatures between 22 ° C and 24 C at a head speed of 2.5 cm / minute (1 inch / min). The impact tests were performed with a drop tower equipped with a 0.625 inch (1.56 cm) matrix and a 0.5 cm (0.5 inch) hemispherical hemispherical indenter (ASTM D2794). The impact operation was comparable regardless of whether the coated surface was on the same or the opposite side of the impact. The mandrel bends were made with a mandrel (Gardner, Pompano Beach, FL, MN-CM / ASTM, ASTM D522) representing the diameters of 3.13 and 3.5 cm (1/8 to 1.5 inches).

EXAMPLES 1-37 Examples 1-37 illustrate the synthesis of different types of copolymers for use in the mixtures of the present invention. The general method described above was followed. Tables 1, 2 and 3 below report the results of representative latex procedures. In the tables, "Size" refers to the grams of monomer used; "Soap" is the moles of surfactant (SDS unless otherwise indicated) per mole of monomer, presuming that the molecular weight is 100; APS are in grams; the monomer proportions are in '* > in weigh; and Mn and M "are in thousands.

Table 1 (Copolymers of Type 1) APS Size of Ex. No. Size 'Soap' Salt MMA BMA EA BA Sty MAA Part. nm Tg ° C Mnxl0"J M xlO -3 1 200 0.0070 0.4 74.0 25.0 1.0 71 150 517 2 200 0.0053 0.4 98.0 2.0 114 191 467 3 400 0.0042 1.0 98.0 2.0 124 303 728 4 400 0.0042 1.0 98.0 2.0 118 130 603 200 0.0070 0.2 78.0 20.0 2.0 80 194 628 6 200 0.0053 0.4 98.0 2.0 124 131 399 7 200 0.0070 0.4 83.0 15.0 2.0 90 185 555 8 200 0.0094 0.4 84.0 15.0 1.0 90 152 428 9 200 0.0070 0.4 85.0 15.0 57.0 82 169 475 400 0.0052 0.4 85.0 15.0 81 216 698 11 400 0.0042 0.4 84.0 15.0 1.0 70.0 89 223 676 12 800 0.0042 0.4 84.0 15.0 1.0 73.0 90 418 940 13 * 200 0.0025 0.4 84.0 15.0 1.0 91.0 100 234 891 14 800 0.0042 0.4 84.0 15.0 1.0 86 334 852 200 0.0070 0.4 50.0 50.0 69 267 1100 16 200 0.0035 0.4 75.0 25.0 98 186 536 17 200 0.0018 0.4 64.0 15.0 20.0 1.0 83 192 608 17-1 200 0.0018 0.4 99.0 1.0 84.0 66 155 414 Soap is Ipegal CO-425 f Size = g. of monomer used * Soap = moles of surfactant / ol of monomer oe EXAMPLE 38 This Example illustrates the mixing of the copolymers and the effects of mixing on film formation in the absence of plasticizers. The following components were mixed in a vigorous shaking test tube: 1.0 ml of P (MMA / EA / MeOEA / MA) (Example 18 of Table 2, TfJ 42 ° C) 0.10 ml of trimethylphenylammonium hydroxide, (PTMAOH), (0.42 molar in deionized water), and 1.0 ml of P (MMA / EA / MA) (Example 1 of Table 1, Tq 71 ° C). The resulting dispersion was fluid, moderately viscous and stable for 20 minutes without evidence of flocculation. A coating was made on microscope slides (2"x 3", 5.01 to 7.162 cm) by means of a scraper blade (0.015"gap, 0.0381 cm) and then dried in an oven at 130 ° C at atmospheric pressure during 20 minutes The resulting coating was apparently optically transparent without cracks or fissures and without evidence of exudate surfactant The coated surface was hydrophobic and homogeneous and was characterized by creep and lead contact angles of 43 ° and 30 respectively. = 10.4 MPa.

EXAMPLES 39-46 These Examples illustrate binary mixtures of a Type I polymer with Type II or III polymers. To determine the maximum polymer fraction of Type I in the mixtures that could be unplasticized in crack-free coatings, mixtures similar to those in Example 38 were prepared. The films were molded and dried as in Example 38. All samples were dried at 80 ° C / 5 minutes followed by drying at 130 ° C for 20 minutes. In those examples with pH > 6, the methacrylic acid residues on the polymer were neutralized with either phenyltrimethyl ammonium hydroxide (Aldrich Chemical Co., Milwaukee / Wl). Table 4 below indicates the composition ranges forming the film and the hardness of various binary dispersion mixtures, with compositions based on% by weight solids. As shown in Table 4, all binary and ternary mixtures containing more than 55% of the Type I polymer were found suitable for film formation in the absence of aggregate plasticizers due to the formation of cracks or fissures during drying. (The Comparative Examples were indicated as "Comp." In i Table 4). This supports the theory that if the percentage of colloidal particles of T, high (of Type I) is very high, So that the MFT remains above 35 ° C in the absence of added plasticizer, then attempts to create a coating by drying under atmospheric pressure result in the formation of cracks and fissures that destroy the integrity of the coating. It is believed that these cracks are a consequence of the internal capillary efforts that develop when drying water progresses in a porous coating. It is further believed that these pores are a direct consequence of the inability of the polymer particles to deform in shapes that fill the spaces during drying. Apparently, including a suitable fraction of T-polymer particles, low (Type II or III) in the dispersion, those particles can deform sufficiently to fill the pores, thus preventing the formation of internal capillary stresses and cracks or fissures. Apparently, the minimum amount of deformable particles required to fill the pores is about 45t. Also, in the binary mixtures of Example 41, the Type II component (the polymer of Example 21) has a T, of 49 ° C, which is roughly the limit for type I polymers. Example 41 shows that, in East Example, at least 70% of Type II polymer was required (Example 21) to avoid cracking in the binary mixtures with the polymer of Example 2. Apparently, for This Type II polymer, particularly rigid, requires a larger fraction thereof to fill the pores. A preferred example of the invention for binary mixtures is Example 7 (Type I), 20 to 50% by weight, mixed with Example 22, 80-45% by weight.

Table 4 Eg No. Type I (Tg),? Type II or II (Tg),% ES MPa Comments 39 Ex. 1 (71 ° C) Ex. 18 (42 ° C) A (Comp.) 59 41 7.0 12.9 cracks B 52 48 7.5 12.9 without cracks C 48 52 7.5 12.5 w. 40 Ex. 2 (114 ° C) E - 18 (42 ° C) A 50 50 7 15.3 without cracks B 40 60 7 18.3 w «c 30 70 7 12.2 w w D 20 80 7 11.1 v \ w 41 Ex. 2 (114 ° C) Ex. 21 (49 ° C) A (Comp.) 50 50 7 17.6 cracks B (Comp.) 45 55 7 15.6"w C (Comp.) 40 60 7 15.3 «» ' D. { Comp ..}. 35 65 7 15.1 w " E 30 70 7 13.9 without cracks Ex. 2 (114 ° C) Ex. 22 (34 ° C) A 50 50 7 15.0 without cracks B 45 55 7 14.2 «w C 40 60 7 13.2 D 35 65 7 13.2 E 30 70 7 11.2 G 25 75 7 10.9 H 20 80 7 10.1 vv w Ej- 2 (114"C) E] 35 f - 1 ° C) A (Comp. ) 60 40 - 6.6 cracks B 50 50 - 4.3 without cracks C 40 60 - 2.4 \\ v \ D 30 70 - 0.7 v \ v \ E 20 80 - 0.7 E - 7 (90 ° C) Ex. 22 (34 ° C) A (Comp.) 60 40 6 - cracks B 55 45 6 12.1 without cracks C 50 50 6 12.0 D 45 55 6 11.3 -v vv E 40 60 6 10.8 \\ w F 35 65 6 10.2 «vv G 30 70 6 9.5 \ v% \ H 25 75 6 9.2 «« I 20 80 6 8.6 Ex. 12 (90'C) E.}. . 26 (34CC) A 23.6 55.0 8 10 without cracks B 19.4 45.3 8- 12 «« 46 Ej- 2 (114 ° C) Ej- 35 (- 1 ° C) A (Comp.) 60 40 11.2 cracks B 50 50 11.2 without cracks c 40 60 10.0 w vv D 30 70 9.3 E 20 80 7.7 46-1 Ex. 17-1 (66CC) Ex. 34-1 (29 ° C) A 50 50 - 8.8 without cracks B 40 60 - 7.4 without cracks C 30 70 - 5.9 without cracks D 20 80 4.8 without cracks "'Indicates that the samples contain white Ti02 pigment (Ti- Pure * R-902 at 6 and 11% PVC)." Comp. "Indicates a Comparative Example EXAMPLES 47 TO 49 Examples 47-49 illustrate ternary mixtures between polymeric (acrylic) latex dispersions of Type I, Type II, and Type III, without plasticizer. The examples, summarized in Table 5, were made by the same procedure as Example 38, except that the prescribed portion of Type III polymer was also added. The compositions were dried at 80 ° C / 5 minutes followed by drying at 130 ° C for 20 minutes. The data illustrate variations in hardness with compositions for coatings prepared without plasticizers. Again, the comparative examples, indicated by "Comp." in Table 5, they show that mixtures containing more than 55% Type I polymer exhibited cracks or fissures. Preferred examples of the invention for the ternary mixtures are Example 9 (Type 1) < 50% by weight mixed with Example 23 (Type II), 25 to 69%, and Example 38 (Type III), 7 to 35% by weight. Note that those have KHN > 5 MPa.

Tabl to 5 KHN El. NO. Type 1 l ^ g), «Type II (Tg),» Type III (Tg),% pH MPa Comments 47 E3. 2 (114'C) 20 (40'C) EJ. 35 (-1 ° C) A (Catp.) 70 15 15 7 - cracks B (Ccpp.) 60 20 20 7 - vv w c 50 25 25 7 7.8 without cracks D 40 30 30 7 7.1 «V E 30 35 35 7 5.2 «\\ F 20 40 40 7 3.3 «\\ 48 Ex. 2 (114'C) ET. 21 (40 C) Ex. 35 (-1 ° C) A 50 25 25 7 8.6 B 45 27.5 27.5 7 6.8 «w c 40 30 30 7 7.1 v \ w D 35 32.5 32.5 7 4.9 «w E 30 35 35 7 5.0 «u 9 Ex. 9 (82 ° C) Ex. 23 (30 ° C) Ex. 36 (-24 ° C) A 50 25 25 6 6.6 B 40 30 30 6 5.7 c 30 35 35 6 4.6 D 20 40 40 6 3.1 e 50 37.5 12.5 6 9.4 F 40 45 15 6 8.3 G 30 52.5 17.5 6 6.0 H 20 • 60 20 6 4.7 I 50 42.8 7.2 6 10.2 J 40 51.4 8.6 6 9.5 K 30 60 10 6 7.9 L 20 68.6 11.4 6 5.5 EXAMPLES 50-62 These Examples 50-62 illustrate the correlations between the mutual adhesion and the ductility of the mixture, involving a comparison of the failure modes of the corresponding mixtures and sheets. Table 6 summarizes the results of the sheet adhesion tests for various pairs of acrylic copolymers and the mechanical properties of the films prepared from a 50:50 mixture of the corresponding dispersions. The comparative examples, which do not fail cohesively, are indicated by M (C) "in Table 6. The mixing films were characterized as ductile if the Elongation at break exceeds 10%. The failure of the sheet was characterized as adhesive if the two films can be detached cleanly without tearing, and cohesive if one or the other component is torn before they can be peeled off. Note that the distinction between ductile and brittle mixtures is independent of hardness (KHN). The ductility was strongly correlated with the mutual adhesion, that is, the mixtures that are ductile correspond to sheets that fail cohesively. It is equally consistent that the sheets for Example 55 fail by a combination of the cohesive and adhesive modes and the corresponding blends have elongations ranging from 8.5% to 97% depending on the composition of the mixture (see Table 7).

Table 6 Mixture Ex. No. Type I Type II Type III Failure of the KHN Sheet Failure 50 (C) - Ex. 30/31 - 3 fragile adhesive 51 (C) Ex. 12 Ex. 31 - \\ vv 6.2 52 (Or Ex. 9 Ex. 31 - - 7.0 53 (C) Ex. 12 - Ex. 37 w \\ 3.5 54 Ex. 15 - Ex. 37 - 2.8 (marginal) 55 Ex. 16 Ex. 31 - adhesive / cohesive - (marginal) 56 Ex. 16 Ex. 26 - cohesive 12 ductile 57 Ex. 15 Ex. 31 -%. 7 58 Ex. 15 Ex. 33 - V? 11.6 59 Ex. 15 Ex. 31 - \\ 5.2 60 Ex. 15 Ex. 32 - W 8.0 61 Ex. 15 - Ex. 36 w 2.4 62 Ex. 12 - Ex. 36 \ v 1.9 EXAMPLES 63-70 Examples 63 to 70 illustrate the mechanical properties of binary mixtures in which butyl methacrylate is a common comonomer. Table 7 summarizes the hardness and tensile properties for binary mixtures of poly (butyl methacrylate), Type II homopolymer (Example 31) with two different type I copolymers prepared from butyl methacrylate and methyl methacrylate. Mixtures with Example 15 are apparently more ductile (as reflected by greater elongation at break) than those with Example 16. This seems to correlate with the increasing content of common comonomer (butyl methacrylate) in the components of the Type I, namely 25% in Example 16 versus 50% in Example 15. The examples in Table 7 show that, for mixtures with poly (butyl methacrylate) as a component of the Type II, the ductility can be increased by increasing the content of butyl methacrylate in the Type I component. Comparative Example 63, marked as "(C)" in Table 7 represents the limiting case of marginal ductility in the sample elongations under tension but nevertheless fails at an elongation of less than 10%. The mutual adhesion between the interfaces of immiscible polymers correlates with the ductility of the mixture, it is believed that they relate to the degree of molecular intermixing at the interface. Apparently, when polymers are more closely related in their thermodynamic properties, such as when they share a significant fraction of common comonomer, then such intermixing increases.

Table 7 KHN Modulus elongation tenacity% of Ex. No. Type 1 Type 2 MPa GPA% MPA MPA elongation Ex. 16 Ex. 31 »by weight? by weight 63 (C) 50 50 6.8 1.4 5 32 28 8.5 64 40 60 5.3 0.99 7 23 17 21 65 30 70 3.9 0.88 7 18 10 35 66 20 80 2.5 0.81 6 16 14 97 Ex. 15 Ex. 31% by weight% by weight 67 50 50 6.3 1.2 6.5 26 16 45 68 40 60 4.4 1.0 7 21 15 73 69 30 70 3.8 0.81 6 18 16 127 70 20 80 3.4 0.66 6.5 15 13 131 EXAMPLE 71 This Example illustrates, based on the mixtures of Example 44, the tensile test of the binary mixtures. The mechanical properties of the blends (Example 44) between the Type I polymer (Example 12) and the Type II polymer (Example 26) were compared with those of the pure components. (The pure polymer films of Example 26 were prepared with the aid of a volatile plasticizer, all others were prepared by drying and annealing the corresponding dispersions without adding plasticizers). Table 8 summarizes the traction, impact and flexibility at room temperature (approximately 24JC). Pure Type I polymer films are brittle, as exemplified by an elongation of 5% without elastic deformation, while the films of all Type I polymer blends from 50 to 20% (44C, 44E, 44G, and 441) were ductile (elongations> 10% followed by elastic deformation). This ductility was also manifested in the resistance to impact and in the folds with mandrel. The values of Young's modulus (E) are typical of thermoplastic polymers at T < Tg and are essentially independent of the composition of the mixture. The elastic limits (sy) are increased with the content of the Type I polymer. The compositions and hardness of the binary mixtures were measured in Table 4 above. E is the Young's modulus, s and represents the maximum stress due to elongation that occurs at elongations of approximately 5%. All coatings, except for Example 12, were cast or molded from dispersions without plasticizer.

Table 8 Ißpplo del E s. '• Toughness No. 1 Type GPa MPa Weight MPa inch-lbs Mandrel 12 100 1.5 n.a. 5 52 - - 44C 50 1.7 36 46 29 50 < 1.8" 44E 40 1.8 34 107 27 - - 44G 30 1.7 31 165 27 80 < 1.8" 441 20 1.6 28 187 27 - - 26 0 1.0 26 294 26 _ _ EXAMPLE 72 This Example illustrates, based on the mixtures of Examples 44 and 48, the mechanical dynamic properties of the coatings obtained from binary and ternary mixtures. Table 9 summarizes the dynamic storage module E 'at a frequency of 1 Hz at 24 ° C and 62 ° C. (The last temperature corresponds to the midpoint between T ,, (I) and Tg (II) At 24 ° C, £ 'is almost independent of the composition of the mixture because both Type I and II polymers remain vitreous to This temperature For comparison, the maximum and minimum theoretical values of E '(62 ° C) were calculated from the values for the pure components corresponding to the same temperature according to the equations of Z. Hashin &S. Shtrikmann (J. Mech, Phys. Sol., 1963, vol.11, pp. 127-140) This theory describes the maximum and minimum modules that can be achieved for all possible isotropic structures composed of the same two phases of the component to a fraction. In the given volume, for Example 4C, the experimental value of E '(62 ° C) has 691 of the theoretical maximum and 79 times greater than the minimum, for Example 41, E' (62 ° C) is only 6 % of the theoretical maximum and 5.6 times greater than the minimum, such variations suggest that the Type I phase it comprises a more extended or continuous structural element in E 44C than in E 441.

Table 10 summarizes the dynamic mechanical data for the ternary mixtures of Example 8. The storage modules for the series of ternary mixtures in Example 38, where the weight fractions of the Type II and Type III components remained the same always, they have also been exemplified in Table 10. In this series, as with binary mixtures, the value of E 'at 81.5 ° C (the midpoint between Tq (I) and T ^ (II)) remains greater than 10 MPa. The value at ambient temperatures was slightly reduced in relation to the binary mixtures due to the presence of the Type III component with T? (III) <; 24 ° C. At 24 ° C, E 'decreases with the increase of Type III polymer due to T, (III) «-1 ° C. However, E '(81.5 ° C) > 10 MPa in T-30, has values comparable to those of binary mixtures with the same polymer content of Type I (see, for example, Table 9).

Table 9 - E '(24UC) E' (62 ° C) Theoretical (62 ° C) ' Ex. No. »Type I t" < ? rc Tß (II) 'C GPa GPa min max (GPa) 7 100 90 - 2.2 1.4 - - 44C 50 90 34 1.9 0.31 0.0039 0.52 44E 40 90 34 1.9 0.14 0.0030 0.40 44G 30 90 34 1.8 0.038 0.0023 0.29 441 20 90 34 1.8 0.010 0.0018 0.18 22 0 - 34 1.4 0.0011 _ _ Table 10 E '' (24 ° C) Ex. No.% Type I T, (I) ° C Tß (II) ° C or (III) ° c GPa E '(81.5nC) 8A 50 114 49 -1 1.1 0.29 48B 45 114 49 -1 1.05 0.20 48C 40 114 49 -1 0.74 0.099 48D 35 114 49 -1 0.59 0.047 48E 30 114 49 -1 0.54 0.019 It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (9)

1. An aqueous dispersion comprising a mixture of polymeric components, each in the form of colloidal particles having average hydrodynamic radii of less than 500 n, the polymeric components, are characterized in that they comprise: a first polymeric component comprising from 20% to 50% in volume of the total polymeric content and exhibit a Tq (I) measure greater than or equal to 49 ° C; a second polymeric component comprising from 45% to 80% by volume of the total polymeric content and exhibiting a measured T (II) of less than 49 ° C and greater than 24 ° C; and a third polymeric component comprising 0% to 35% by volume of the total polymeric content and exhibiting a measured T (III) of less than 24 °; wherein each of the first, second and third polymer components have an Mw greater than 80,000 Daltons and are mutually adherent; and wherein the aqueous dispersion has a volatile organic content of less than 20% by weight of the total polymer content.

2. The aqueous dispersion according to claim 1, characterized in that the particles have average hydrodynamic radii less than 100 nm.

3. The aqueous dispersion according to claim 1, characterized in that the Tq of the components reflect the effect of the addition of a non-volatile plasticizing agent.

4. The aqueous dispersion according to claim 1, characterized in that the content of volatile organic components is less than 10% by weight of the total polymeric content of the aqueous dispersion.

5. The aqueous dispersion according to claim 1, characterized in that after drying at atmospheric pressure at temperatures greater than or equal to 35 ° C and annealing at temperatures higher than T, (I), a continuous, homogeneous coating is formed, which is characterized by a balance of hardness, ductility and rigidity at temperatures higher than T < , (II), such properties represented, respectively, by a KHN = 3 MPa at 2 ° C, tensile elongations greater than or equal to approximately 20%, and E'UHz) > 10 MPa to T - [Tq (I) + Tq (II)] / 2; and where the properties are obtained without, cross-linking or branching molecular chains of the polymer components, during drying or annealing, to increase the sensitivity of the molecular weights of the polymeric components.

6. The aqueous dispersion according to claim 5, characterized in that the hardness of the film is represented by KHN = 5MPa.

7. The aqueous dispersion according to claims 1, 2, 3, 4, or 5, characterized in that the polymeric components are homopolymers or copolymers comprising comonomers selected from the group consisting of acrylic and methacrylic acid and the respective esters and amides thereof , acrylonitrile, styrene and its derivatives, 1,3-butadiene, isoprene, ethylene, propylene, chloroprene, vinyl acetate, vinyl chloride, vinyl fluoride, and vinylidene fluoride.

8. The aqueous dispersion according to claim 7, characterized in that the polymeric components are linear or branched copolymers.

9. A paint or coating composition, characterized in that it comprises from about 10% by weight to about 50% by weight of binder solids polymeric, the binder solids comprise from about 30% by weight to about 100% by weight of the aqueous dispersion according to claims 16 and 5.