MXPA00007458A - Coating compound - Google Patents

Abstract

Coating material (I) comprising a mixture of at least two miscible, cosolvent-free, aqueous anionic polyurethane-urea dispersions (A) and (B), in which (A) (as dry film) shows a glass transition point (Tg) of -30 to -45 degrees C, (B) shows two Tg's, one at -30 to -45 degrees C and the other at +45 to +60 degrees C, and the mixture shows only one Tg at -30 to -45 degrees C. Independent claims are also included for:(a) varnish made from (I), applied to any substrate as a mixture of (A) and (B) and then dried at up to 150 degrees C;(b) a method for the production of (I) by making dispersions (A) and (B) separately and mixing them together in a wt. ratio of 50-90 parts (A) to 10-50 parts (B);(c) coating material made by mixing (A) and (B) in a wt. ratio of 55-85 parts (A) to 15-45 parts (B).

Description

COATING COMPOSITIONS BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to light-stable coating compositions containing a blend of at least two aqueous, anionic, anionic, co-solvent-free dispersions A and B of mutually compatible polyurethane polyureas. The present invention also relates to recyclable release coating compositions consisting of at least two aqueous, anionic, co-solvent-free aqueous dispersions A, and B, of different polyurethane polyureas, a process for their production and their use as coating compositions. , preferably as removable coating compositions for the temporary protection of automobiles, airplanes, steel and aluminum profiles, glass and plastic discs and other arbitrary substrates and process for the recovery of the detached coating layers used.

DESCRIPTION OF THE PREVIOUS TECHNIQUE The anionic polyurethane polyurea dispersions are known. They are also known REF .: 122069 Aqueous, anionic, co-solvent-free dispersions of polyurethane polyureas, the process for their production and their use as coating compositions, coating agents, adhesives and release coating compositions. DE-A 19 653 585 discloses polyurea dispersions which, after physical drying at 20 ° to 100 ° C, preferably at 20 ° to 80 ° C, provide high-gloss transparent coatings, resistant to UV, resistant to temperature (- 30 to 80 ° C), which are resistant to precipitation (organic or inorganic in nature), and which on the one hand adhere well to the substrates and which on the other hand can easily be removed by detachment. The breaking strength and the elongation of the coating layers are suitably high. A coating dispersion can be obtained according to DE-A 19 653 585, hereinafter referred to as dispersion A. Known from WO 98/23692 are polyolefin mixtures used as removable coating compositions for automobiles. However, these mixtures do not contain any polyurethane (PUR) component. The release liner described herein is also not recyclable.

There is a need for the higher hardness and lower elongation coatings of the polyurethane ureas A used as recyclable release coating compositions. Therefore, it is an object of the present invention to provide novel aqueous anionic polyurethane polymers which can be used without problems and in an ecologically favorable manner and which produces coating compositions and coatings meeting the requirements contemplated for mechanical properties, wear, strength to light, transparency, resistance to temperature, detachment capacity, resistance to water, resistance to precipitation and recyclability (organic and inorganic in nature), and that also show a high hardness and lower elongation. One possibility of producing a higher degree of hardness of the dry coating layers lies in rationing the polymer molecules. Branched polyurethane polyureas, as described in EP-A 242 731, have a higher hardness which is used to produce non-flexible, hard substrates, for example as parquet coatings. When applied in a cosolvent-free manner to the glass plates, the coatings satisfactorily adhere the layers showing ruptures after drying at room temperature. These coating layers can not be peeled off like a film. A dispersion produced from EP-A 242 731 is hereinafter referred to as dispersion B. It has now surprisingly been found that the desired application properties are obtained if at least two aqueous anionic dispersions A and B free of polyurethane polyurethane co-solvent are mixed., miscible with each other, whose dried films A have a glass transition temperature Tg in the range of -30 ° to -45 ° C and the dry films B have a first Tg in the range of -30 ° to -45 ° C and a second Tg in the range of + 45 ° to + 60 ° C, and the mixture of A and B as a dry film has only one Tg in the range of -30 ° to -45 ° C. It is extremely surprising that a mixture of the dispersions A and the dispersions B form cohesive, removable and recyclable films, since one skilled in the art has expected that the good adhesion of the dispersion B would have also been transferred to the mixture of the composition of coating of dispersion A and B, preventing detachment. This, however, is not the case. With the mixtures according to the invention, high gloss, highly transparent and hard coating layers are obtained, which have a superior filling capacity and good release and recycling.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to light stable coating compositions comprising a mixture of at least two aqueous, anionic, anionic, co-solvent-free dispersions of polyurethane polyureas, where the polyurethane dispersion A as a dry film has a Tg in the range of -30 ° to -45 ° C and the polyurethane dispersion B as a dry film has a first Tg in the range of -30 ° to -45 ° C and a second Tg in the range of + 45 ° to + 60 ° C, and the mixture of A and B as a dry film has only one Tg in the range of -30 ° to -45 ° c. The present invention also relates to light-stable coatings applied in the form of a mixture of at least two aqueous dispersions compatible with each other to arbitrary substrates and dried at temperatures up to 150 ° C. The present invention also relates to a process for producing the light-stable coating compositions according to the invention, wherein at least two aqueous, anionic, co-solvent-free aqueous polyureas dispersions A- and B are prepared separately from polyurethane polyureas. and the aqueous dispersions A and B are then mixed in relation to the weight of 50 to 90, preferably 55 to 85 parts of A of 10 to 50, preferably 15 to 45 parts of B (based on solids). The present invention also relates to the use of mixtures of aqueous dispersions A and B for the preparation of solvent-free, water-resistant, light-stable coatings for the protection of vehicles, steel, aluminum and metal objects of all kinds. type, glass and plastic of all kinds, mineral substrates, bricklaying and natural stones, to prevent the corrosion of ships, bridges, airplanes, railways, and to protect objects of wood and natural products and other substrates by immersion, blade coated, molded , sprayed, painted by brush or spray and followed by drying between 20 ° to 150 ° C. The present invention relates to the use of mixtures of aqueous dispersions A and B or recyclable release coating compositions for the temporary protection of automobiles, railroads, ships, furniture, metal objects, mineral objects, glass and plastic objects and other substrates by immersion, knife coating, molding, spraying, spray painting or painting by brush and followed by drying at 20 ° to 100 ° C, preferably 20 to 80 ° C, thermal or infrared light, microwave radiation or sonic irradiation. The present invention also relates to the use of release coatings used according to the invention as recycle materials, where the detached coatings optionally used after pre-cleaning, are mechanically ground, dissolved, optionally heated, in acetone, water and water repellents. neutralization, preferably ammonia, the acetone is optionally removed by distillation under reduced pressure and the recovered coating composition recovered in the form of an aqueous dispersion is obtained for reuse. The present invention also relates to the use of the detached coating layers used according to the invention as a recycling material, where the detached coating layers used, optionally after a preliminary cleaning, are mechanically crushed and then pressed into hot air presses. under the application of temperature and pressure to form polyurethane plates, or the crushed coating layers are extruded in an extruder applying temperature, cutting forces and transport, in thermoplastic endless strands and the obtained strands are granulated by known granulation methods for form cylindrical, spherical, lenticular or rhomboidal granules. The present invention also relates to removable liners for the temporary protection of automobiles, aircraft, steel and aluminum profiles, glass and plastic discs and other arbitrary substrates. Finally, the present invention relates to the use of the resulting granules for the production of industrial and technical articles such as thermoplastic elastomers by further processing in the technological process of the known plastics, for example by injection molding, blow molding, thermoforming, molded in mud or flat extrusion.

DETAILED DESCRIPTION OF THE INVENTION Suitable dispersions A for the light-stable coating compositions according to the invention include anionic, aqueous, co-solvent-free dispersions of polyurethane polyureas, the solids of which contain the reaction product present at least partially in the salt form of a) an NCO prepolymer prepared from i) 20 to 60% by weight of a diisocyanate selected from the aliphatic diisocyanates, cycloaliphatic diisocyanates and mixtures thereof, ii) 20 to 80% by weight of a macrodiol which has an average molecular weight number of 500 to , 000, iii) 2 to 12% by weight of 2,2-bis- (hydroxymethyl) alkanecarboxylic acids, preferably dimethylolpropionic acid, iv) 0 to 15% by weight of short chain diols with a molecular weight of 62 to 400 , v) 0 to 10% by weight of monohydric alcohols as chain regulators with a molecular weight of 32 to 350, b) 0 to 15% by weight of diamines in the molecular weight range of 60 to 300 as chain extenders, c) 0 to 10% by weight of chain regulator, selected from the group of monoamines, alkanolamines and ammonia, d) 0 to 3% by weight of water and e) 0.1 to 10% by weight of neutralizing agents, where the total percentage indicated 100%, provided that in the prepolymer stage a) the content of NO calculated is 65 to 85%, preferably 75 to 80%, of the theoretical NCO content. Suitable dispersions B for the light-stable coating compositions according to the invention include anionic, aqueous, co-solvent-free dispersions of polyurethane polyureas, the solid contents of which contain the following reaction product, present at least partially in the form of salt of: a) an NCO prepolymer prepared from i) 20 to 60% by weight of a diisocyanate selected from the group of aliphatic diisocyanates, cycloaliphatic diisocyanates and mixtures thereof, ii) 10 to 80% by weight of a macrodiol with an average number of molecular weight from 500 to 10,000, iii) 2 to 12% by weight of 2,2-bis- (hydroxymethyl) alkanecarboxylic acids, preferably dimethylolpropionic acid, iv) 0 to 15% by weight of chain diols and triols cut with a molecular weight of 62 to 400, v) O to 10% by weight of alcohols, monohydric as chain regulators with a molecular weight of 32 to 2500, b) 0 to 15% by weight of diamines and triamines n a molecular weight in the range of 60 to 300 as chain extenders, c) 0 to 10% by weight of chain regulator, selected from monoamines, alkanolamines and ammonia, d) 0 to 3% by weight of water and) 0.1 to 10% by weight of neutralization agents, where the total percentage indicated added up to 100% ', provided that the branching was carried out with trioles and / or triamines where both are not one of iv) and b) may not be zero . Dispersions A and B contain the components described in more detail below; the specific characteristics of dispersions A and B are described below. Component a) i) is selected from aliphatic and / or cycloaliphatic diisocyanates, such as isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate, i-methyl-2,4-diisocyanato-cyclohexane and / or l-methyl -2,6-diisocyanato-cyclohexane, 1,6-hexamethylene diisocyanate and / or 1,3-cyclohexane diisocyanate.

It is also possible to use small amounts of aromatic diisocyanates such as 2,4- and 2,6-toluene diisocyanate or 2,4'- and 4,4'-diphenylmethane diisocyanate. As component a) ii) macrodiols with an average molecular weight number of 500 to 10,000 are used. These macrodiols are preferably polyester diols obtained by reacting carboxylic acids with diols, optionally with the aid of conventional esterification catalysts, preferably by melt condensation or azeotropic condensation at temperatures of 140 ° -240 ° C. Examples of suitable acids or anhydrides include adipic acid, succinic acid (anhydride), maleic acid (anhydride), sebacic acid, azelaic acids, the various commercially available dimer fatty acids (in hydrogenated and non-hydrogenated form), phthalic acid (anhydride), isophthalic acid, tetrahydrophthalic acid (anhydride), 1,4-cyclohexanedicarboxylic acid and hexahydrophthalic acid (anhydride). Examples of diols that are industrially available include ethylene glycol 1,2- and 1,3-propanediol, 1,3- and 1,4-butanediol, 1, β-hexanediol, diethylene glycol, dipropylene glycol, neopentyl glycol or mixtures of such diols. Preferred are polyester diols of adipic acid, hexanediol and neopentyl glycol. Also suitable are polycarbonate diols, polycaprolactone diols, hydroxy-polytetrahydrofurans or hydroxypolyethers based on propylene oxide. Suitable polycarbonate diols are obtained, for example, by reacting carbonic acid derivatives including diphenyl carbonate or phosgene with alcohols, preferably diols of the type indicated above. The average number of molecular weight of these polyols is between 500 and 10,000, preferably between 700 and 4,000, and more preferred between 1,000 and 2,500. The starting components a) iii) are selected from 2,2-bis- (hydroxymethyl) alkanecarboxylic acids having a total of 5-8 carbon atoms, ie compounds of formula (I) where R represents an alkyl radical with 1 to 4 carbon atoms. 2, 2-Dimethylolpropionic acid is preferred. Suitable starting components a) iv) include the short chain diols described above of molecular weight 62-400. 1,4-Butanediol is preferred. Suitable starting materials a) v) include methanol, ethanol, butanol, hexanol, 2-ethylhexanol, octanol and dodecanol and alcohols of molecular weight from 32 to 350. Suitable components b) include aliphatic and / or cycloaliphatic compounds which have at least two amino groups reactive to isocyanates. Suitable compounds include ethylenediamine, propylene diamine, hexamethylenediamine, isophorone diamine, p-xylylenediamine, 4,4'-diamino-dicyclohexylmethane and 4,4'-diamino-3'3 dimethyldicyclohexylmethane. Suitable c) components include ammonia, monofunctional amines such as methylamine, ethylamine, n-propylamine, isopropylamine, cyclohexylamine, octylamine, diethylamine, dibutylamine, and amino alcohols such as ethanolamine, diethanolamine and propanolamine.

Suitable neutralization agents e) include ammonia, N-methylmorpholine, dimethyl isopropanolamine, triethylamine, dimethylethanolamine, methyldiethanolamine, triethanolamine, morpholine, tripropylamine, ethanolamine, diethanolamine, triisopropanolamine, and N-ethyldiisopropylamine. In a preferred embodiment components a) i), ii) and iii) are placed in a reactor and reacted under anhydrous conditions in a temperature range of 50 ° -150 ° C, preferably 50 ° 110 ° C. Then the reaction mixture is then cooled and acetone is added as well as the short chain diol (iv) and optionally the monohydric alcohols (v) and the whole mixture is heated until the NCO content of the mixture is reduced to a value from 65 to 85% of the theoretical NCO content. In this way the NCO prepolymer is formed. After this the reaction mixture is diluted with acetone and the calculated amount of a mixture of diamine and the chain switch - dissolved in water - is added. In this way 90% of the NCO groups of the prepolymer are reacted with the chain extender, the diamine and the chain switch, allowing the rest to react with the water present. The remaining isocyanate can react with the water present to form the polyurethane polyurea according to the invention. The polymer formation reaction is preferably carried out without the use of the catalysts, but it is also possible to use the catalysts known in the chemistry of isocyanates (for example tertiary amines such as triethylamine, tin compounds such as tin octoate-II, and dibutyltin dilaurate and other known catalysts). When no more NCO can be detected (measured by IR), the calculated amount of neutralizing agent, preferably the ammonia solution, is added to the reaction mixture so that 50-60% of the carboxyl groups present with the ammonia are neutralized. ammonia The desired solids concentration is adjusted by adding water followed by removal of the acetone by distillation. The polyurethane polyurethane dispersions obtained according to the process of the invention contain 20-60% by weight of solids, preferably 30-40% by weight of solids in water, and their particle diameters "media reach 20-1000 nm, preferably 50-500 nm.

The pH of the dispersions of the storage-stable polyurethane polyurea, according to the invention, are in the range from 6 to 9. Suitable dispersions B are obtained according to processes known from the prior art. The production methods are described as branched polyurethane plastics in EP-A 0 242 731 (corresponding to U.S. 4,745,151 incorporated herein by reference). EP-A 269 972 (corresponding to U.S. 4,764,555 incorporated herein by reference) discloses polyurethane polyurethane dispersions modified with monohydric polyether alcohols and neutralized with ammonia. The dispersions B contain branched compounds. Examples of triols include trimethylolpropane and glycerol, or triamines such as diethylenetriamine. The preferred polyether alcohols polyol alcohols are monofunctional, containing ethylene oxide and propylene oxide optionally, are preferably initiated on n-butanol and have average molecular weights of 250 to 2,500. Since these polyether alcohols act as nonionic hydrophilic groups, they preferably contain more than 50% by weight of ethylene oxide in the chain.

The dispersions A and B can be mixed with other anionic or nonionic dispersions. Examples include plastic dispersions with polyvinyl acetate, polyethylene, polystyrene, polybutadiene, polyvinyl chloride, polyacrylate and copolymer. The dispersions A and B are mixed in a proportion of resin solids of 50 to 90 parts of A to 10 to 50 parts of B, preferably 55 to 85 arts of A to 15 to 45 parts of B. The pH of the mixtures can be optionally adjusted with organic or inorganic bases, such as ammonia, alkali metal carbonates, amines or aminoalcohols. The organic bases are preferred. Especially preferred is 2-a__ino-2-methyl-1-propanol. The known additives used in the chemistry of the coating composition, such as pigments, light stabilizers, anti-deposition agents, thickening agents, surfactants and defoamers, can be used in the formulation of the coating compositions. The coating compositions are applied by conventional methods used in coating technology, i.e. by dipping, knife coating, molding, spraying, spray painting, brushing or roller coating.

The coatings according to the invention are water resistant, transparent, tear resistant, UV resistant, temperature resistant, resistant to precipitation (against precipitation of an organic or inorganic nature) and optionally pigmented coatings which are Adhere to the substrates, and otherwise they can easily be removed by detachment. The coating compositions serve as release coatings for the temporary protection of automobiles, profiled parts of steel and aluminum, discs and articles of glass and plastic. After application the coated parts are dried at room temperature or at elevated temperatures of up to 150 ° C / (100 °). If the polyurethane urea dispersions according to the invention are dried for up to 30 min at 140 ° -150 ° C, then the coatings which adhere well to the substrates are obtained. Higher drying temperatures above 150 ° C are also possible, although the use of high temperatures is generally uneconomical. The recycling of the detached coatings used is very simple. The detached coating layers, optionally after a pre-cleaning, are mechanically ground, dissolved in acetone in a reaction vessel, optionally under heat, and optionally filtered after dissolution. The neutralizing agent of the calculated amount is added, preferably ammonia, and the desired solids content of the aqueous polyurethane polyurea dispersion is completely diluted with water. Finally, the acetone is optionally distilled under reduced pressure. Another method of recycling the layers of detached coatings used is that the detached coating layers optionally used after the pre-cleaning are mechanically crushed and then the crushed material is pressed into presses with hot air under the application of temperature and pressure to form polyurethane plates. It is also possible to extrude the crushed coating layers into a. extruder by applying temperature, cutting forces and transport, in the endless thermoplastic strands and the granulation of the resulting strands according to known granulation method to form cylindrical, spherical, lenticular or rhomboidal granules. The granulates are used as thermoplastic elastomers in the production of industrial articles by additionally processing by known processes used in the technology of plastics, for example by injection molding, blow molding, thermoforming, mud molding or flat extrusion.

The invention is further illustrated but is not intended to be limited by the following examples wherein all parts and percentages are by weight unless otherwise specified.

EXAMPLES Example 1: Dispersion A The groups were dehydrated in a reaction vessel with 170 g (0.1 mole) of a polyester of adipic acid, 1,6-hexanediol and neopentyl glycol (molar ratio of glycols 65:35) with an average number of molecular weight of 1,700 g / mol and 2% OH at 120 ° C and 10 mbar with stirring. Under a nitrogen atmosphere were added 13.4 g (0.1 mol) of dimethylolpropionic acid and 111 g (0.5 mol) of isophorone diisocyanate. After 1 hour of reaction time at 110 ° C the reaction mixture was cooled to 60 ° C and dissolved in 100 g of acetone. Then 18 g (0.2 mol) of 1,4-butanediol was added, the reaction mixture was stirred for 22 hours at 50 ° C. The NCO content was 1.60% (calculating 2.04%). The reaction mixture was diluted with 500 g of acetone. A mixture of 10.6 g (0.062 mol) of isophorone diamine, 1.07 g (0.016 mol) of the 25% ammonia solution and 60 g of water were added to the NCO prepolymer at 50 ° C. The whole mixture was then stirred for 5 hours at 50 ° C. The reaction mixture was neutralized with 3.4 (0.05 mol) of 25% ammonia solution and dispersed with 450 g of water. The acetone was removed at 50 ° C and 150 mbar and a white dispersion with a solids content of 39.2% and an average particle size of 263 nm was obtained. The degree of neutralization was 50%. The Tg (vitreous transition temperature) of a dry film was -38".0 ° C. DSC measurements: To achieve the same initial conditions, the samples were stored for 3 days under normal climatic conditions (SCC) and packed in tight DSC capsules under normal climatic conditions DSC equipment: DSC-2 Differential Scanning Calorimeter (Perkin-Elmer) Two consecutive warming -100 ° C to + 80 ° C (1st heating) and -100 ° C to +120 ° C (2nd heating), heating rate 20 ° C / min, rapid cooling between them at the initial temperature of -100 ° C, rinsing with nitrogen, weight of the sample portions between 12.9 mg and 13.3 mg in 30 μl capsules Evaluation: (2 ° heating) vitreous transition (vitreous transition temperature, TG, as the vitreous stage medium, height of the vitreous stage).

Example 2: Dispersion A Example 1 was repeated, except that the ammonia was replaced as a neutralizing agent with 3.56 'g (0.04 mol) of dimethylethanolamine. Then, to remove the acetone, a white dispersion with a solids content of 35% and an average particle size of 309 nm was obtained. The degree of neutralization was 40%.

Example 3: Dispersion A Example 1 was repeated, except that the reaction mixture was neutralized with 4.08 g (0.06 mol) of a 25% ammonia solution and dispersed with 680 g of water. After removing the acetone, a white dispersion with a solids content of 31.4% and an average particle size of 183 n was obtained. The degree of neutralization was 60%.

Example 4: Dispersion A The groups were dehydrated in a reaction vessel for 30 minutes with 254.1 g (0.125 mol) of a polyester of adipic acid, 1,2-ethanediol and 1,4-butanediol (molar ratio of the glycols 67:33) with an average molecular weight of 1961 g / mol and 1.73% OH at 120 ° C and 10 mbar. Under a nitrogen atmosphere, 16.75 g (0.125 mol) of dimethylolpropionic acid and 131 g (0.5 mol) of dicyclohexylmethane-4, '-diisocyanate were added. After 1 hour of reaction time at 110 ° C the reaction mixture was cooled to 80 ° C and dissolved in 250 g of 2-butanone. After adding 11.25 g (0.125 mol) of 1,4-butanediol the reaction mixture was stirred for 12 hours at 80 ° C. The NCO content was 1.36% (calculated 1.61%). The reaction mixture was diluted at 50 ° C with 500 g of acetone. A mixture of 13.6 g (0.08 mol) of isophoronediamine, 1.36 g (0.02 mol) of a 25% ammonia solution and 100 g of water was added to the NCO prepolymer at 50 ° C. The whole mixture was then stirred for 1 hour at 50 ° C. The reaction mixture was neutralized with 4.45 g (0.05 mol) of dimethylethanolamine and dispersed with 530 g of water. after removing the organic solvents at a temperature above 50 ° C and 100 mbar, a white dispersion with a solids content of 38.7% and an average particle size of 480 nm was obtained. The degree of neutralization was 40 ' Example 5: Dispersion A In a reaction vessel were dehydrated for 30 minutes with 170 g (0.1 mole) of the polyester of Example 1 at 120 ° C and 10 mbar with stirring. Under a nitrogen atmosphere, 13.4 g (0.1 mol) of dimethylolpropionic acid and 111 g (0.5 mol) of isophorone diisocyanate were added. After 1 hour of reaction time at 110 ° C the reaction mixture was cooled to 60 ° C and dissolved in 100 g of acetone. After adding 18 g (0.2 mol) of 1,4-butanediol, the reaction mixture was stirred for 21 hours at 50 ° C. The NCO content was 1.63% (calculated 2.04%). The reaction mixture was diluted with 500 g of acetone. A mixture of 1.09 g (0.016 mol) of a 25% ammonia solution and 60 g of 50 ° C water was added to the NCO prepolymer and the whole mixture was stirred for 21 hours at 50 ° C. The reaction mixture was neutralized with 3.4 (0.05 mol) of a 25% ammonia solution and dispersed with 450 g of water. After removing the acetone at a temperature of up to 50 ° C and 150 mbar, a white dispersion with a solids content of 39.8% and an average particle size of 210 nm was obtained.

Example 6: Dispersion B In a reaction vessel were dehydrated for 30 minutes with 60 g (0.035 mol) of a polyester of adipic acid, 1,6-hexanediol and neopentyl glycol (molar ratio of glycols 65:35) with an average molecular weight of 1,700 g / mol, 90.5 g (0.108 mol) of a polyester of adipic acid and 1,6-hexanediol with an average molecular weight of 840 g / mol and 17.8 g (0.008 mol) of a polyether (initiated with n-butanol , - containing 83% ethylene oxide and 17% propylene oxide and having an average molecular weight of 2,240 g / mol) at 120 ° C and 15 mbar. Under a nitrogen atmosphere, 20.75 g (0.155 mol) of dimethylolpropionic acid was added followed by the addition of 192 g. (0.86 mol) of isophorone diisocyanate at 75 ° C. After stirring for 3 hours at 75 ° C, 13.25 g (0.147 mol) of 1,4-butanediol and 5.25 g (0.04 mol) of trimethylolpropane were added to the reaction mixture. After stirring for another 3 *? _ Hours the NCO content was 7.5% (calculated 7.51% of NCO). The prepolymer was dissolved in 992 g of acetone and reacted at 50 ° C with a mixture of 16.3 g (0.27 mol) of ethylenediamine, 20.2 g (0.12 mol) of a 9.7% ammonia solution and 200 g of water. The whole mezcal was stirred for 50% at%, neutralized with a mixture of 13.6 g (0.078 mol) of a 9.7% ammonia solution and 10 g of water, and then dispersed for a further 15 minutes with stirring at 50 ° C. adding 525 g of water. The acetone was distilled off to 50 ° C and 150 bar. A white dispersion with a solids content of 35% and an average particle size of 120 nm was obtained. The degree of neutralization was 50%. The first Tg of a dry sample B was -43.5 ° C and the second Tg was + 56.5 ° C.

Example 7: Preparation of a release coating composition a) Transparent formulation 75.52 parts by weight of dispersion A of Example 1 (39.2% solids content) were mixed with stirring with 21.12 parts by weight of dispersion B (content of 35% solids) and adjusted to approximately 0.33 parts by weight of 90% aminomethylpropanol at a pH of about 8.3. Then 0.37 parts by weight of a commercially available acrylate thickener (Borchigel A LA, 10% in distilled water), 1.11 parts by weight of a commercially available 1% defoamer (antifoam E, Bayer AG), 0.51 parts by weight were added quickly. weight of a wng agent (Hydropalat 110, Henkel) and 1.04 parts by weight of a light stabilizer dilutable in water (Sanduvur 3055, Clariant GmbH) and completely mixed by a dissolving apparatus. The system is ready to be used, for example by a spray application without air, after approximately 8 hours of ripening at 23 ° C. The Tg of a dry coating layer of dispersions A and B in the proportion of the specified mixture was -41 ° C. b) White Transparent Formulation 72.14 parts by weight of the dispersion A of Example 1 were premixed with stirring. (39.2% solids content) with 20.18 parts by weight of dispersion B (35% solids content) and adjusted with approximately 0.32 parts by weight of 90% aminomethylpropanol to a pH of about 8.3. Then 4.38 parts by weight of the ground paste indicated below, 0.36 parts by weight of "a commercially available acrylate thickener (Borchigel A LA, 10% in distilled water), 1.09 parts by weight of a commercially available antifoam were added rapidly. (antifoam E, Bayer AG), 0.51 parts by weight of a wetting agent (Hydropalat 110 Henkel) and 1.02 parts by weight of a light stabilizer dilutable in water and mixed thoroughly using a dissolving apparatus .The system is ready to be used, for example for an airless spray application, after providing 8 hours of maturation at 23 ° C. The ground pulp, which after a previous dispersion using a dissolver was ground for about 30 minutes in a cooled ball mill, containing 42.26 parts by weight of dispersion A, 11.77 parts by weight of dispersion B, 3.70 parts by weight of distilled water and 41.48 parts by weight of dioxide of titanium (TRONOX R-KB-4, Kerr McGee Pigments GmbH), and 0.45 parts by weight of a wetting agent (Tego Wet 250, Tego Chemie) and 0.34 parts by weight of an anti-deposition agent (Aerosil R 972, Degussa).

Example 8: Recycling A residual degree of neutralization of 2.8% was found by titration measurement in a release liner film prepared from the dispersions A and B in a weight ratio of 80:20. 300 g of this film were dissolved at 45 ° C in 600 g of acetone and 90 g of water and then neutralized with 10.5 g of a 9.7% ammonia solution. The mixture was then dispersed with 360 g of water and the acetone was removed at 40 ° C and 120 mbar. The white dispersion thus obtained had a solids content of 40.5% and a measured degree of neutralization of 58.5%. The films applied to the glass with a 200 μm doctor blade after drying at 80 ° C were clear, bright and detachable. Although the invention has been described in detail in the foregoing for the purpose of illustration, it will be understood that the detail is for the purpose only and that variations may be made herein by those skilled in the art without departing from the spirit and scope of the invention. invention except as may be limited by the claims. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers. Having described the invention as above, property is claimed as contained in the following:

Claims (14)

1. A coating composition comprising a mixture of at least two dispersions A and B of aqueous anionic polyurethane polyureas, characterized in that the dispersion A as a dry film has a TG in the range of -30 ° C to -45 ° C , and dispersion B as a dry film has a first Tg in the range of -30 ° C to -45 ° C and a second TG in the range of + 45 ° C to + 60 ° C, and the mixture of A and B as a dry film has only one TG in the range of -30 ° C to -45 ° C.

2. The composition of coatings according to claim 1, characterized by being free of cosolvent.

3. The coating composition according to claim 1, characterized in that the aqueous, anionic dispersions A and B are mixed in a weight ratio of 50 to 90 parts of A to 10 to 50 parts of B, based on the resin solids of A and B.

4. The coating composition according to claim 1, characterized in that the two dispersions A and B are mixed in a weight ratio of 55 to 85 parts of A to 15 to 45 parts of B, based on the solids of A and B.

5. A coating obtained by applying a coating composition containing a mixture of at least two aqueous and anionic polyurethane polyurethane dispersions A and B, characterized in that dispersion A as a dry film has a TG in the range of -30 ° C. at -45 ° C, and dispersion B as a dry film has a first Tg in the range of -30 ° C to -45 ° C and a second TG in the range of + 45 ° C to + 60 ° C, and the mixture of A and B as a dry film has only one TG in the range of -30 ° C to -45 ° C. substrates include vehicles, steel, aluminum and metal objects of all types, glass and plastic of all kinds, mineral substrates, bricklaying and natural stones, to prevent corrosion of ships, bridges, airplanes, railways, and for the protection of objects of wood and natural products and other substrates and dried at temperatures above 150 ° C.

6. The coating according to claim 5, characterized in that it is obtained by drying at temperatures between 20 to 100 ° C.

7. A process for obtaining a coating by applying the coating composition containing a mixture of at least two dispersions A and B of aqueous anionic polyurethane polyurea, characterized in that dispersion A as a dry film has a TG in the range of -30 ° C to -45 ° C, and dispersion B as a dry film has a first Tg in the range of -30 ° C to -45 ° C and a second TG in the range of +45 ° C to + 60 ° C, and the mixture of A and B as a dry film has only one TG in the range of -30 ° C to -45 ° C. followed by drying at 20 ° to 150 ° C.

8. The process according to claim 7, characterized in that the drying is carried out from 20 ° C to 100 ° C.

9. The process according to claim 7, characterized in that the drying is carried out at 20 ° C to 80 ° C.

10. The process according to claim 7, characterized in that the drying is performed by heat or infrared light, microwave irradiation or sonic irradiation.

11. A process for recycling the release liner according to claim 5, characterized in that it includes the steps of detaching the coating from the substrate, and optionally after a previous cleaning, mechanically grinding, dissolving in acetone, water and neutralizing agents, and optionally it is heated, the acetone is optionally distilled under reduced pressure, and the coating composition is recovered in the form of an aqueous dispersion.

12. A process of recycling a coating prepared from a coating composition containing a mixture of at least two aqueous and anionic polyurethane polyurethane dispersions A and B, characterized in that the dispersion A as a dry film has a TG in the range of - 30 ° C to -45 ° C, and dispersion B as a dry film has a first Tg in the range of -30 ° C to -45 ° C and a second TG in the range of + 45 ° C to + 60 ° C, and the mixture of A and B as a dry film has only one TG in the range of -30 ° C to -45 ° C. it includes the steps of detaching the coating from the substrate, optionally after a preliminary cleaning, mechanically grinding and then forming polyurethane plates, thermoplastic endless strands, or forms of cylindrical, spherical, lenticular or rhomboidal granules.

13. The process according to claim 12, characterized in that the forming step includes compressing in hot air presses under increased temperature and pressure to form the polyurethane plates.

14. The process according to claim 12, characterized in that the forming step includes extruding the crushed coating in an extruder under increased temperature, cutting forces and transport, in thermoplastic endless strands * and the obtained strands are granulated by granulation methods known to form cylindrical, spherical, lenticular or rhomboidal granules. COATING COMPOSITIONS SUMMARY OF THE INVENTION The present invention relates to coating compositions comprising a mixture of at least two dispersions A and B of aqueous anionic polyurethane polyureas, where dispersion A as a dry film has a TG in the range of -30 ° C to -45 ° C, and dispersion B as a dry film has a first Tg in the range of -30 ° C to -45 ° C and a second TG in the range of + 45 ° C to + 60 ° C, and the mixture of A and B as a dry film has only one TG in the range of -30 ° C to -45 ° C.