MXPA01000080A - Aqueous coating composition comprising an addition polymer and a rheology modifier - Google Patents

Abstract

The invention relates to an aqueous coating composition comprising a mixture of 90 to 99 wt.%of a film forming binder composition comprising an alkali non-swellable core-shell addition polymer dispersion (I), and 1-10 wt.%of a rheology modifying addition polymer dispersion (II). It is required that the total amount of (meth)acrylic acid in 100 parts of the total addition polymer (I) is less than 1.75 wt.%. The aqueous coating composition of the present invention can be advantageously used as a base coat in a base coat/clear coat system. This use shows a decrease in strike-in effect compared to previous known base coat/clear systems.

Description

AQUEOUS COMPOSITION OF COATING COMPRISING AN ADDITION POLYMER AND A RHEOLOGY MODIFIER DESCRIPTIVE MEMORY The invention relates to an aqueous coating composition based on a dispersion mixture of an addition polymer and a rheology modifier. Preferably, this aqueous coating composition is mixed with a metallic pigment, such as aluminum, or a pigment, such as a mica coated with metal oxide so that said coatings with a metallic appearance can be obtained. In this way, a differential light reflection effect referred to as "abrupt change" is obtained. A problem with coating systems that have a metallic appearance is to obtain a large abrupt change as well as great brightness. To obtain a large abrupt change, the metallic pigment on the application of the coating composition must be and remain well oriented. To obtain a high gloss, the coating containing metallic pigment is provided with a transparent coating called pigmented. In general, this system is known as a "base coat / clear coat" system. During actual practice, the base coat will be sprayed with a clear coat, without prior cure of the base coat ("wet on wet"). Due -., t.t; Since the clearcoat usually contains organic solvents, steps must be taken to prevent the disorientation of the metallic pigment in the basecoat as a result of the coating of the basecoat. base that was weakened by organic solvents in the transparent coating ("penetration"). An aqueous-based coating composition is known from EP-A-0 038 127, that is, an interlaced core shell dispersion whereby the shell, upon swelling, provides the desired rheological properties. Interlacing reduces penetration. However, a disadvantage of this system is that the composition of the coating will have few film-forming properties, which will manifest themselves in the few mechanical properties. Another aqueous-based coating composition of EP-A-0 287 144 is known, that is, a non-interlaced, swelling core shell dispersion having an amount of methacrylic acid in the shell from 10 to 60 mol% . The non-interlaced, swellable core shell dispersion having more than 2% by weight methacrylic acid in 100 parts of an addition polymer is illustrated. A decrease in penetration is also observed in this modality. Both systems described in EP-A-0 038 127 and EP-A-0 287 144 contain in the shell a batch of carboxylic groups, neutralized by an amine to provide the desired rheological properties. However, because of this large amount of salt groups, coatings based on these compositions, especially when applied and cured at room temperature, show little resistance to water. The present invention now provides an aqueous coating composition that can be used as a basecoat in a basecoat / clearcoat system, which has good mechanical properties, high abrupt change, high gloss, virtually no penetration and good strength. the water. Due to the fact that the high solids contents can be obtained with the aqueous coating composition of the present invention, a reduction of the drying times in the number of coatings is obtained. In one or more of these properties the aqueous coating composition of the present invention shows improvements over others described in EP-A-0 038 127 and EP-A-0 287 144. The aqueous coating composition according to the invention comprises a mixing of 90 to 99% by weight of a film-forming binder composition comprising a dispersion of core shell addition polymer that is not swelled with alkali (I), and 1 to 10% by weight of a polymer dispersion of addition (II) that modifies the rheology, the sum of the% by weight indicated for the film-forming binder composition and the dispersion (II) being always 100% by weight, wherein the dispersion of the polymer (I) was prepared in two or more steps by emulsion polymerization, and was obtained by copolymerization in a first step of '»- a, -?' - '(I) 60 to 95 parts by weight (calculated on 100 parts by weight of the total addition polymer (I)) of a mixture of monomers A consisting of (i) 65 a 100 mol% of a mixture of (a) 10 to 98 mol% of a (cyclo) alkyl (meth) acrylate of which the cycloalkyl group contains from 4 to 12 carbon atoms, (b) from 0 to 55% molecular of styrene, (c) from 2 to 15 mol% (metha) hydroxyalkyl acrylate, and (d) from 0 to 20% (cyclo) alkyl (meth) acrylate, the sum of the molar% indicated for the monomers (a) ), (b), (c) and (d) is always 100 mol%, and (ii) from 0 to 35 mol% of a different copolymerizable monoethylenically unsaturated monomer, the sum of the molar% indicated for the components (i) and (ii) is always 100 mol%, and by copolymerization in a subsequent step of (2) 5 to 40 parts by weight (calculated on 100 parts by weight of the total addition polymer (I) of a mixture of monomers B which consists of (e) 1 to 10 mol% acid (met) acrylic co, (f) 2 to 20 mol% of hydroxyalkyl (meth) acrylate, (g) 0 to 55 mol% styrene and (h) 15 to 97 mol% of a different monoethylenically unsaturated copolymerizable monomer, the sum of the molar% indicated for the monomers (e), (f), (g) and (h) it is always 100 mol%, with the carboxylic acid groups derived from the acid (meth) acrylic being at least partially neutralized, resulting in a non-interlaced addition polymer I, whereby the total amount of (meth) acrylic acid in 100 parts of the total addition polymer (I) is less than 1.75% by weight, and wherein the dispersion of the polymer (II) was prepared by the emulsion polymerization, and was obtained by copolymerization of (iii) 99.5-99.99 parts by weight (of the total addition polymer (II)) of a mixture of monomers C which consists of (j) 10 to 80% by weight (meth) acrylate of (cyclo) alkyl, (k) 20 to 50% by weight (meth) acrylic acid, (m) 0 to 20% by weight (meth) ) hydroxyalkyl acrylate, and (n) 0 to 20% by weight of a different monoethylenically unsaturated copolymerizable the sum of the% by weight indicated for the monomers (j), (k), (m) and (n) is always 100 % molar, and (v) 0.01 to 0.05 parts by weight (calculated on 100 parts by weight of the total addition polymer (II)) of a compound having at least two unsaturated groups, the carboxylic acid groups derived from (meth) acrylic acid being at least partially neutralized. Preferably, in the first step of the preparation of the polymer dispersion (I), a mixture of monomers A was used consisting of (i) 80 to 100 mol% more preferred 100 mol%, of a mixture of (a) 30 to 95 mol% of a (cyclo) alkyl (meth) acrylate of which the (cyclo) alkyl group contains from 4 to 12 carbon atoms, (b) 0 to 50 mol% of styrene, (c) 5 a 12 mole hydroxyalkyl (meth) acrylate, and (d) 0 to 8 mole% of maleate and / or di (cyclo) alkyl fumarate of which the (cyclo) alkyl group contains from 4 to 12 carbon atoms, and ( I) 0 to 20 mol%, preferably 0 mol%, of a different copolymerizable monoethylenically unsaturated monomer. As examples of suitable cycloalkyl (meth) acrylates for use in the mixture of monomers A and having a group of cycloalkyls with 4 to 12 carbon atoms may be mentioned: butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, octyl acrylate, octyl methacrylate, isobornyl acrylate, isobornyl methacrylate, docecyl acrylate, dodecyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, and mixtures thereof. Preference is given to butyl acrylate, butyl methacrylate and mixtures thereof. Examples of hydroxyalkyl methacrylates are 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 6-hydroxyethyl acrylate, phydroxycyclohexyl acrylate, methacrylate p-hydroxycyclohexyl, hydroxypolyethylene glycol (meth) acrylates, hydroxypolypropylene glycol (meth) acrylates and mixtures thereof. 2-Hydroxyethyl methacrylate is preferred.

As examples of di (cyclo) alkyl maleates and / or fumarates with (cyclo) alkyl groups having from 4 to 12 carbon atoms suitable for use in the mixture of monomers A may be mentioned dibutyl maleate, dibutyl fumarate, 2-ethylhexyl maleate, 2-ethylhexyl fumarate, octyl maleate, isobornyl maleate, dodecyl maleate, cyclohexyl malate and mixtures thereof. Suitable monoethylenically unsaturated copolymerizable monomers for use in the monomer A mixture include: alkyl (meth) acrylates having less than 4 carbon atoms in the alkyl group, such as methyl methacrylate, methyl acrylate, acrylate ethyl, ethyl methacrylate, propyl acrylate, propyl methacrylate, and isopropyl acrylate; maleates and alkyl fumarates having less than 4 carbon atoms in the alkyl groups, such as dimethyl maleate, diethyl maleate, diethyl fumarate and dipropyl maleate; (meth) acrylates having ether groups such as 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate and 3-methoxypropyl acrylate; monovinyl aromatic hydrocarbons, such as vinyl toluene, methyl-methyl styrene and naphthalene; acrylamide and methacrylamide; nitriles such as acrylonitrile and methacrylonitrile; N-alkyl (meth) acrylamide such as N-isopropylacrylamide, N-isopropylmethacrylamide, N-t-butylacrylamide, N-t-octylacrylamide, N-N-dimethylaminoethyl methacrylate, N-N-diethylaminoethyl methacrylate; monomers such as vinyl chloride, vinyl acetate, vinyl propionate, and vinyl pyrrolidone, and monomers containing one or more urea or urethane groups, such as, for example, the reaction product of 1 mmol of isocyanate methacrylate. ethyl and 1 mmol of butylamine, 1 mol of benzylamine, 1 mmol of butanol, 1 mmol of 2-ethylhexanol, and 1 mmol of methanol, respectively. Mixtures of these compounds can also be used. Preferably, in a second step of the preparation of the polymer dispersion (I), a mixture of monomers B is used, consisting of (e) 5-8 mol% of (meth) acrylate acid, (f) 5- 12 mol% of hydroxyalkyl (meth) acrylate, (g) 0-30 mol% of styrene, and (h) 50-90 mol% of a different copolymerizable monoethylenically unsaturated monomer. Above mentioned examples of hydroxyalkyl (meth) acrylates. 2-hydroxyethyl methacrylate is preferred. Examples of monoethylenically unsaturated copolymerizable monomers that can be used in the mixture of monomers B include the aforementioned examples for monoethylenically unsaturated copolymerizable monomers that can be used in the monomer mixture A. Also included are cycloalkyl methacrylates having a group of cycloalkyl with 4 to 12 carbon atoms. Examples of the same were also mentioned before. Mixtures of these compounds were also used. Preferably, the monoethylenically unsaturated copolymerizable monomers were selected from methyl methacrylate, butyl acrylate, butyl methacrylate, and mixtures thereof. Preferably, the polymer dispersion (I) was prepared by the emulsion polymerization of (1) 70 to 90, preferably 75 to 85, parts by weight of mixture of monomers A and (2) 10 to 30, preferably 15 to 25, parts by weight of monomer mixture B. Optionally, different mixtures of monomers A and / or B can be used successively. Since the addition polymer (I) is not interlaced, the choice of the monomers in the mixtures of monomer A and B is such that the functional groups have different unsaturated bonds which can not be reacted with each other under the reaction conditions for the preparation of the addition polymer. The total amount of the (meth) acrylic acid in 100 parts of the total addition polymer (I) is required to be less than 1.75% by weight, preferably less than 1.5% by weight, more preferably between 0.5 and 1.4% by weight. In this way, the polymer dispersion (I) can not be inflated. The acid value is 3 to 10 mg KOH / g, preferably 5 to 8 mg KOH / g. The addition polymer (I) has a PM n of 50,000 to 2,000,000 preferably 100,000 to 1,000,000.

Preferably, the monomer mixture C used in the preparation of the polymer dispersion (II) consists of 0) 50-70% by weight of (cyclo) alkyl (meth) acrylate (k) 30-40% by weight of (meth) acrylic acid, (m) 0-5% by weight of hydroxyalkyl (meth) acrylate, and (n) 0-5% by weight of a different copolymerizable monoethylenically unsaturated monomer. Preferably, the polymer dispersion (II) was prepared by the emulsion polymerization of (iii) 99.85-99.95 parts by weight of the monomer mixture C and (iv) 0.05-0.15 parts by weight of a compound having at least two unsaturated groups. Preferably, the cycloalkyl methacrylates in mixtures of monomers C have alkyl groups with 1 to 4 carbon atoms. Examples include methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate. , isobutyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, t-butyl acrylate, t-butyl methacrylate, and mixtures thereof. Methyl acrylate, ethyl acrylate, and propyl acrylate are preferred.

Examples of hydroxyalkyl (meth) acrylates and monoethylenically unsaturated copolymerizable monomers that are used in the monomer C mixture were given above for mixtures of monomers A and B. Examples of the compound having at least two unsaturated groups include divinyl toluene, divinyl benzene, trivinyl benzene , divinylnaphthalene, ethylene glycol di (meth) acrylate, trimethylene glycol di (meth) acrylate, 2-ethylhexane-1, 3-dimethacrylate, divinylxylene, ethyl divinylbenzene, divinyl ether, divinyl sulfone, allyl ethers of polyhydric compounds, such as glycerol , pentaerythritol, sorbitol, sucrose and resorcinol, allyl ethers of polyisocyanate compounds, such as triallyl isocyanurate, divinylketone, divinyl sulfide, allyl (meth) acrylate, allyl maleate, diallyl fumarate, diallyl phthalate, diallyl succinate, diallyl carbonate, diallyl malonate, diallyl oxalate, diallyl adipate, diallyl sebacate, diallyl tartrate it, diallyl silicate, triallyl citrate, triallyl phosphate, and N, N'-methylene di (meth) acrylamide. A compound having at least two unsaturated groups of which at least one is an allylic group is preferred. More preferred are diallyl phthalate, allyl methacrylate and triallyl isocyanurate. The addition polymer (II) has an acid value of 175 to 350 mg KOH / g, preferably 200 to 300 mg KOH / G, and a hydroxyl value of 150 mg KOH / g, preferably 0 to 100 mg KOH / g. By means of the emulsion polymerization, the polymerization of the monomer mixtures of ethylenically unsaturated monomers in water in the presence of an insoluble or water-soluble initiator and 0.1-5% by weight, preferably 0.3-2.5% by weight (calculated on The total monomer mixture or mixtures of an emulsifier The polymer dispersion (I) was prepared by the emulsion polymerization as described in A-0 287 144. The polymer dispersion (II) was prepared by the emulsion polymerization as described in GB 870 994. Emulsifiers in which their use is preferably made in the emulsion polymerization are anionic and / or nonionic in nature Examples of anionic emulsifiers include: potassium laurate, potassium stearate, potassium oleate , sodium decyl sulfate, sodium dodecyl sulfate, sodium dodecylbenzene sulphonic acid, and sodium rosinate. Examples of nonionic emulsifiers include in: ethers and thioethers of alkyl and alkylaryl polyethylene glycol and of polypropylene glycol, alkylphenoxypoly (ethyleneoxy) -ethanols such as the adduct of 1 mmol of nonylphenol and 3-12 moles of ethylene oxide; alkyl (ethyleneoxy) ethanols with 8 to 18 carbon atoms in the alkyl groups, such as the adduct of a 1 mmol dodecanol and 3 to 12 moles of ethylene oxide. Examples of emulsifiers include anionic and nonionic groups are ammonium or sodium sulfate salts of alkyl phenoxypoly (ethyleneoxy) ethanols, such as the adduct of 1 mmol of nonyl phenyl and 3 to 12 moles of ethylene oxide, and the ammonium or sodium salts of the alkyl (ethyleneoxy) sulfate ethanol with 8 to 18 carbon atoms in the alkyl groups, such as adduct of 1 mmol of C12-14 alcohol and 3 to 12 moles of ethylene oxide. The ammonium or sodium sulfate salt of the adduct of 1 mmol of C12-? 4 alcohol and 3 to 12 moles of ethylene oxide is preferred.

Also, in the emulsion polymerization, conventional radical initiators can be used in the usual amounts. Examples of suitable radical initiators include water-soluble initiators such as ammonium persulfate, sodium persulfate, potassium persulfate and t-butyl hydroperoxide, and water-soluble initiators such as bis (2-ethylhexyl) peroxydicarbonate, dinitide peroxydicarbonate. butyl, t-butyl perpivalate, eumeno hydroperoxide, dibenzoyl peroxide, dilauroyl peroxide, 2,2, azobis, butyronitrile, and 2,2, -azobis-2-methylbutyronitrile. Suitable reducing agents which may be used in combination with for example a hydroperoxide may be mentioned: ascorbic acid, sulfoxylated sodium formaldehyde, thiosulfates, bisulfates, hydrosulfates, water-soluble amines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, N.N'-dimethylethanolamine and N, N-Diethylethanolamine and reducing salts such as cobalt, iron, nickel and copper sulfate. Optionally, a chain length regulator can be used, for example n-octylmercaptan, dodecyl mercaptan, and 3-mechaptopropionic acid. The copolymerization of the monomer mixtures is generally carried out at atmospheric pressure at a temperature of 40 to 100 ° C, preferably 60 to 90 ° C, in an atmosphere with an inert gas, such as nitrogen. However, optionally, the copolymerization can also be carried out at elevated pressure. However, the reaction conditions for the monomer mixtures A and B should be chosen in such a way that the functional groups have different unsaturated bonds in the monomer mixtures which can not react with one another. According to the invention, the carboxylic acid groups derived from acrylic acid and / or methacrylic acid are at least neutralized to 40-100% by the addition of a neutralizing agent. Suitable neutralizing agents for the carboxylic acid may be mentioned ammonia and amines such as N, N-dimethylethanolamine, N, N-diethylethanolamine, 2- (dimethyl) -amino-2-methyl-1-propanol, triethylamine, and morpholine. It is preferred that the neutralizer of the carboxylic acid groups be carried out after the polymerization. The coating composition according to the invention preferably comprises a mixture of 92-95% by weight of a film-forming binder composition comprising a non-swellable alkali (I) core polymer addition shell, and 7.5% by weight of a polymer dispersion of addition (II) that modifies the rheology. The composition of the coating of the present invention consists essentially of water being an aqueous coating composition. However, about 20% by weight of a liquid content of a coating composition can be organic solvent. As organic solvents there can be mentioned such alcohols containing ether groups such as hexyl glycol, butoxyethanol, 1-methoxy-propanol-2, 1-ethoxy-propanol-2, 1-propoxy-propanol-2, 1-butoxy-propanol-2 and 1-isobutoxy-propanol- '«**! < ** 2; alcohols such as methanol, ethanol, propanol, butanol, pentanol and hexanol; diols, such as ethylene glycol and diethylene glycol. The coating composition according to the present invention can be cured by physical drying. However, alternatively, the coating compositions can be cured in the presence of a curing agent that reacts with hydroxyl and / or carboxyl groups. Examples of suitable curing agents include N-methylol and / or N-methylol ether groups containing aminoplasts obtained by the reaction of an aldehyde, such as for example formaldehyde, with amino or amido groups containing a compound such as melamine, such as Cymel 328, former Cytec, urea, N; N'-ethylene urea, dicyanodiamide, and benzoguanamine. The resulting compounds are preferably completely or partially etherified with alcohols having 1 to 6 carbon atoms, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, amylalcohol, hexanol, or mixtures thereof. Particularly favorable results can be obtained when a methylol melamine having 4 to 6 methyl groups per melamine molecule, at least 3 methylol groups which are etherified with butanol or an etherified condensation product of butanol and N, N formaldehyde are used. '-ethilendiurea. Examples of other suitable curing agents include water-dispersible blocked polyisocyanates or polyisocyanates such as methyl ethylketoxy blockers containing an adduct of a polycarboxylic acid polyisocyanate, for example dimethylol propionic acid, and aliphatic or aromatic carbodiimides.

In addition to the alkali non-swellable alkali metal (I) shell polymer addition dispersion, the film-forming binder composition may also comprise water-dilutable materials such as alkyd resins, polyesters, polyurethanes, and mixtures thereof. Preferably, the water-dilutable material is a polyurethane. The film-forming binder composition may comprise 0.1 to 100% by weight of the alkali (I) non-swellable core polymer shell addition dispersion and 99.9 to 0% by weight of at least one water-dilutable material, wherein the sum of the% by weight indicated for the dispersion (I) and the water-dilutable materials are always 100% by weight. More preferably, the film-forming binder composition can comprise from 1 to 99% by weight and the alkali-non-swellable core (I) polymer shell addition dispersion and 99 to 1% by weight of at least one water-soluble material. Water. Even more preferably, the film-forming binder composition may comprise from 25 to 75% by weight of the alkali non-swellable core (I) polymer shell addition dispersion and from 75 to 25% by weight of at least one dilutable material in water In addition, the coating composition may contain conventional additives and adjuvants, such as pigments, dyeing agents, colorants, and accelerators for the curing reaction; The applicable pigments can have an acid, a neutraliser or a basic character. Optionally, the pigments can be pre-treated to modify the properties. The examples of the suitable pigments tJ, jii-t.? qp * fc. they include metallic pigments such as aluminum and stainless steel; the nacreous pigments, such as mica coated with a metal oxide such as iron oxide and / or titanium dioxide; inorganic pigments, such as titanium dioxide, iron oxide, carbon black, silica, kaolin, talc, barium sulfate, lead silicate, strontium chromate, and chromium oxide; organic pigments such as phthalocyanine pigments. The solid content of the coating composition ranges from 5 to 60% by weight, preferably from 10 to 40% by weight. This depends on whether or not the metallic pigment is used. The presence of metallic pigments results in a low solid content compared to the presence of non-metallic pigments. However, compared to conventional water-based coating systems, and the solid content of the coating composition of the present invention is both high. Preferably, the coating composition according to the present invention was used as a base coat in the so-called base coat / clear coat system to provide a high gloss metallic appearance. For this purpose, the coating composition according to the invention comprises the so-called "non-film-forming" aluminum paste or other metallic pigments. The use of the coating compositions according to the invention as a base coat can prevent the base coat from softening through the clear coat after being sprayed therewith, so that the metallic effect is not lost. The transparent coating used in the basecoat / clearcoat system can for example be a clearcoat lacquer of a conventional polyacrylate / melanin composition. The clear coat may also be a composition with two polyester components or a polyacrylate / polyisocyanate composition. The polyisocyanate can be, for example, 1,6-hexamethylene diisocyanate finished. The coating composition according to the invention can be applied to a substrate in any desired form, such as roller coating, spraying, brushing, spraying, flow coating, immersion, electrostatic spraying, or electrophoresis, preferably by spraying. Suitable substrates can be made of wood, metal and synthetic materials. The curing can be carried out at room temperature or, optionally, at elevated temperatures to reduce the curing time. Optionally, the coating composition can be sewn at elevated temperatures in the range of for example 60 to 160 ° C in a baking oven for a period of 10 to 60 minutes. The clear coat can be applied wet on wet over the base coat. Optionally, the base coat can be partially cured before the application of the clear coat. Also, the base coat can be completely cured before the application of the clear coat. The compositions are particularly suitable in the preparation of coated metal substrates, such as in the refining industry, in particular refined for repairing automobiles and transport vehicles and in large transport vehicles such as trains, trucks, buses, and airplanes. The compositions of the present invention can also be used in the first automotive finishing. The invention will be described later in the following examples, which should not be interpreted as limiting the scope of the present invention.

EXAMPLES The test methods used in the examples are described below. The average particle size of the dispersions was determined by dynamic light scattering, the dispersion being diluted with water to a solids content of approximately 0.1% by weight. The viscosity was determined with a Brookfield viscometer. The solids content was determined according to ASTM D 1644-59 method with heating at 130 ° C for a period of 30 minutes.

The orientation of metal leaflets can be measured with a spectrophotometer. The intensity of the light reflected at an angle ß was measured for a given incident angle. The so-called abrupt change can be obtained by measuring the intensity of reflection (value L) at two different angles. Sudden change =? L = L (ß?) - L (ß2) where L (ß?) = To the intensity of light reflected at an angle of ± 110 ° L (ß2) = to the intensity of the reflected light at an angle of ± 25 ° A transparent coating system / metal base coating of low solid shaded gray exhibits an abrupt change value of approximately 55 to 75 depending on metal grade, when measured in this way. Moisture resistance can be judged visually by the presence of blisters after the test. The following compounds were used. Trigonox A-W70®, 70% by weight t-butyl hydroperoxide in water, former Akzo Nober Chemicals Abex JKB®, ammonium sulfate of an alkyl ethoxylated alcohol, solids content 29.3% by weight, ex Rhone-Poulenc Perlankrol EP36 ®, sodium sulphate adduct of 1 mol dodecanol and 6 mol ethylene oxide, solids content of 29.2% by weight, ex Ackros Rhodapex AB / 20®, adduct ammonium sulfate of 1 mol of 4? C 2- 2- alcohol and 9 moles of ethylene oxide, solids content of 28. 7% by weight ex Rhone-Poulenc Setal EPC 4673, polyester polyol, former Akzo Nober Resins Cymel 328®, melamine interlayer, former Cytec Preparation of polymeric dispersions of alkali non-swellable core shell (I) EXAMPLE 1 A: Preparation of copolymer A of monomer mixture in step 1 A flask 21 fitted with a stirrer, a thermometer, a reflux condenser and drip funnels A and B were filled with: 435.0 g of demineralized water and 12.0 g of Perlankrol EP36® emulsifier. The dropping funnel A was filled with: 280.0 g of monomer mixture I (see Table I). The dropping funnel B was filled with a homogeneous mixture of: 140.0 g of demineralized water and 1.4 g of sodium persulfate. After deaeration, the contents in flask and dropping funnels were brought to a nitrogen atmosphere, and the contents of the flask were heated to 80 ° C, then, the contents of drip funnel B were introduced into a flask during a period of 3 minutes. After the flask contents which were brought back to 80 ° C, the contents of the dropping funnel A were introduced into a flask at a constant rate for a period of 2.5 hours, after the contents of the flask were kept at 80 ° C. ° C for 1.5 hours.

B. Preparation of polymer dispersion (I) in step 2 Drip funnel A was filled with 70.0 g of monomer mixture II (see Table I) and drip funnel B was filled with a homogeneous mixture of: 35.0 g of water demineralized and 0.35 g of sodium persulfate. The contents of a dropping funnel B were introduced into a flask comprising a copolymer A, for a period of 3 minutes. The contents of the flask were brought back to 80 ° C and the contents of the dropping funnel A were introduced into a flask at a constant speed for a period of 1 hour, after the contents of the flask were maintained at 80 ° C, for another 2 hours. The reaction was carried out under a nitrogen atmosphere. During the occlusion of the reaction, the contents of the flask were cooled to 70 ° C, after which 41.3 g of a solution of N, N-dimethylethanolamine in 10 wt% water was added dropwise. Subsequently, the contents of the flask were cooled to room temperature and filtered on a 30 μm filter cloth. The dispersion properties are given in Table II.

EXAMPLE 2 Example 1 was repeated except for the following: A: The preparation of the copolymer A of the monomer mixture A in step 1 The dropping funnel A was filled with 280.0 g of monomer mixture II (see Table I) instead of the mixture of monomers I.

B: The preparation of the polymer dispersion (I) in step 2 The dropping funnel A was filled with 70.0 g of the monomer mixture IV (see Table I) instead of II. After the conclusion of the reaction, 43.5 g of a solution with 10% by weight of N, N-dimethylethanolamine in water was added. The properties of the resulting dispersion are given in Table II.

MY * EXAMPLE 3 A: Preparation of the copolymer A of the monomer A mixture in step 1 A flask 21 fitted with a stirrer, a thermometer, a reflux condenser and drip funnels A and B were filled with: 435.0 g of demineralized water and 12.0 g of Perkankrol EP36® emulsifier. The dropping funnel A was filled with: 280.0 g of monomer mixture I (see Table I). The dropping funnel B was filled with a homogeneous mixture of: 140.0 g of demineralized water and 1.4 g of sodium persulfate. After deaeration, the contents of both the flask and the dropping funnels were brought to a nitrogen atmosphere, and the contents of the flask were heated to 50 ° C, after which 5% of the contents of the drip funnel A were introduced into a flask for a period of 2 minutes. Then, the contents of the flask were heated to 80 ° C and 30% of the contents of the drip funnel B were added to the contents of the flask. The contents of the flask were kept at 80 ° C for 15 minutes, and subsequently the rest of the contents of the drip funnels A and B were introduced into a flask at a constant speed for a period »*, 2.5 hours, after the contents of the flask were kept at 80 ° C for another hour.

B: Preparation of the polymer dispersion (I) in step 2 The dropping funnel A was filled with: 70.0 g of IV monomer mixture (see Table I) and a drip funnel B was filled with a homogeneous mixture of: 35.0 g of demineralized water and 0.35 g of ammonium persulfate. The contents of both dropping funnels were introduced into a flask comprising a copolymer A at a constant rate over a period of 1 hour, after the contents of the flask were maintained at 80 ° C for another hour. During the occlusion of the reaction, the contents of the flask were cooled to 70 ° C, after which 43.5 g of a solution of N, N-dimethylethanolamine in 10 wt% water was added dropwise. Subsequently, the contents of the flask were cooled to room temperature and filtered on a 30 μm filter cloth. The dispersion properties are given in Table II.

EXAMPLE 4 Example 3 was repeated except for the following: A: Preparation of copolymer A from a mixture of monomers A in step 1 The flask was filled with 338.0 g of demineralized water and 13.4 g of Rhodapex AB / 20® emulsifier.

B: Preparation of the polymer dispersion (I) in step 2 Drip funnel A was filled: 70.0 g of the monomer mixture V (see Table I) The properties of the dispersion are given in Table II.

EXAMPLE 5 Example 4 was repeated, except for the following: A: Preparation of copolymer A of the monomer mixture A in step 1 The monomer pre-emulsion is composed of 280.0 g of the monomer mixture VI (see Table I) instead of the monomer mixture III. The properties of the dispersion are given in Table II.

EXAMPLE 6 Example 4 was repeated, except for the following: B: Preparation of polymer dispersion (I) in step 2 Drip funnel A was filled with 70.0 g of monomer mixture 7 (see Table 1) instead of the monomer mixture 5. The dispersion properties are given in the table II. A: Preparation of copolymer A from the monomer A mixture in step 1 EXAMPLE 7 A flask 21 fitted with an agitator, a thermometer, a reflux condenser and drip funnels A and B were filled with: 621.1 g of demineralized water and 5.4 g of 20% by weight of a solution of sodium dodecylbenzenesulfonic acid in demineralized water The dropping funnel A was filled with: 683.8 g of a preemulsion composed of 507.1 of monomer mixture 8 (see Table I) 10.0 g of 20% by weight of a solution of sodium dodecylbenzenesulfonic acid in demineralised water 166.7 g of demineralized water Drip funnel B was filled with 55.3 of a homogeneous mixture of: 55.3 g of demineralized water and 2.0 g sodium persulfate. After deaeration, the contents of both the flask and the dropping funnels were brought to a nitrogen atmosphere, and the contents of the flask were heated to 50 ° C. After a 9.6 g of the contents of the dropping funnel A were introduced into a flask for a period of 1 minute, the contents of the flask were heated to 83 ° C. Subsequently, 25% of the contents of the dropping funnel B were introduced into a flask after the contents of the flask were maintained at 83 ° C for a period of 15 minutes. Subsequently, the remainder of the contents of the dropping funnel A and B were placed in a flask at a constant rate for a period of 3 hours, after the contents of the flask were maintained at 83 ° C for another 30 minutes and Subsequently, they were diluted with 143.3 g of demineralized water.

B. Preparation of polymer dispersion (I) in step 2 Drip funnel A was filled with 126.7 g of monomer mixture 9 (see Table I) and dropping funnel B was filled with a homogeneous mixture of 33.3 g of demineralized water and 0.51 g of sodium persulfate. The contents of both dropping funnels were introduced into a flask comprising a copolymer A, for a period of 1 hour, in which the contents of the flask were kept at 80 ° C, for another hour. During the occlusion of the reactions, the contents of the flask were cooled to room temperature, and filtered on an 80 μm filter cloth, which was added dropwise 13.5 g of a solution of 30% by weight of a solution of N, N-dimethylethanolamine in demineralized water.

The dispersion properties are given in Table II.

EXAMPLE 8 Example 8 was repeated except for the following: A: The preparation of the copolymer A of the monomer mixture A in step 1 The monomer pre-emulsion is composed of: 507.1 g of a mixture of monomers X instead of a mixture of monomers 8.

To use drip funnel B with ammonium persulfate instead of sodium persulfate.

B. Preparation of polymer dispersion (I) in step 2 The monomer mixture is composed of: 126.7 g of monomer mixture XI instead of monomer mixture IX. During the occlusion of the reaction, the dispersion was neutralized with 11.7 g of a solution of 30% by weight of a solution of N, N-dimethylethanolamine in demineralized water instead of 13.5 g of this solution. The dispersion properties are given in Table II.

EXAMPLE 9 Example 8 was repeated except for the following: 226.0 g of demineralized water 3.7 g of Perlankrol EP36® emulsifier. The dropping funnel A was filled with: 680.7 g of a pre-emulsion composed of 507.1 g of monomer mixture X (see Table I) 6.85 g of a Perlankrol EP36® emulsifier and 166.7 g of demineralized water.

B. Preparation of polymer dispersion (I) in step 2 During the occlusion of the reaction, the dispersion was neutralized with 12.8 g of a solution of 30% by weight of a solution of N, N-dimethylethanolamine in demineralized water instead of 11.7 g of this solution. The dispersion properties are given in Table II.

The preparation of polymer dispersions of addition (II) that modify the reoloqia EXAMPLE 10 A flask 21 fitted with an agitator, a thermometer, a reflux condenser and dropping funnels was filled with: 460.0 g of demineralized water and 2.64 g of Abex JKB®. Drip funnel A was filled with: 422 g of mixture a pre-emulsion of monomer composed of: 150.0 g of demineralized water, 12.0 g of Abex JKB® and 260.0 g of a mixture of monomers 12 (see Table I) The funnel drip B was filled with a homogeneous mixture of: 25.0 g of demineralized water and 0.38 g ammonium persulfate.

The dropping funnel C was filled with a homogeneous mixture of: 30.0 g of demineralized water and 0.14 g ammonium persulfate After de-aeration, the contents in both the flask and the dropping funnels were brought to a nitrogen atmosphere, and the The contents of the flask were heated to 85 ° C, then, the contents of the dropping funnel A were introduced into a flask. The contents of the flask were maintained at 85 ° C for 15 minutes. Subsequently, the remainder of the contents of the dropping funnel A and the contents of the dropping funnel C were introduced into a flask at a constant speed for a period of 90 minutes. The dropping funnel a was rinsed with 60 g of demineralized water and after it was introduced into the flask, the contents of the flask were kept at 85 ° C for another 30 minutes. At the time the drip funnel D was filled with a homogeneous mixture of: 30.0 g of demineralized water and 0.60 g of Trigonox A-W70® and a drip funnel E was filled with a homogeneous mixture of: 30.0 g of water demineralized and 0.25 g of a sodium formaldehyde sulfoxylate. «- ^ feál > -; After the contents of the flask were cooled to 63 ° C as the contents of the dropping funnel were introduced into a flask and after 10 minutes the contents of the dropping funnel were introduced into a flask at a constant speed over a period of time. 30 minutes. Subsequently, the contents of the flask were cooled to room temperature and filtered on a 30 μm filter cloth. The properties of the dispersion are given in Table 3.

EXAMPLE 11 Example 10 was repeated except for the following: the dropping funnel A was filled with 260.0 g of monomer mixture 13 (see Table 1) instead of the monomer mixture 12. The dispersion properties are given in Table 3.

EXAMPLE 12 Example 10 was repeated except for the following: the dropping funnel A was filled with 260.0 g of monomer mixture 14 (see Table 1) instead of the monomer mixture 12. The dispersion properties are given in Table 3. you »« tfü '? .

EXAMPLE 13 Example 10 was repeated except for the following: the flask was now filled with 279.7 g of demineralized water and 1.0 g of Abex JKB®. The dispersion properties are given in Table 3.

Base coating compositions EXAMPLES 14-19 AND COMPARATIVE EXAMPLES A AND B Basecoat compositions were prepared as follows. A mixture of 22 g of aluminum paste (65% solids in Aquavex Sparkle Silver E5000AR aromatic / aliphatic hydrocarbons, ex Silberiine) and 28 g of butoxyethanol was added with stirring to a mixture of 190 g of a polymer dispersion (I) according to Examples 1 to 6 and 14 g of a polymer dispersion (II) according to examples 10-12. The base coating compositions were brought to a pH of 7.5-8.0 by the addition of N, N-dimethyl ethanol amine and diluted with water to spray the viscosity (efflux friction time of 35 seconds in DIN cup No. 4) . The solid contents of all the base coating compositions are in a range of 14-16% by weight.

In an atmosphere having a relative humidity of 65% the basecoating compositions of the present invention were sprayed on primer-coated steel test boards in a film thickness of 10-25 μm (in a dry state) in a manner In addition, two test boards were prepared with a low solids solvent based coating based on an acrylic / melamine system (comparative example A) and the aqueous core shell dispersion of example 5 of EP-A-0 287 144 (comparative example B). After drying a mat to room temperature, the boards adhered freely. Then, these test boards were partially covered and the remaining parts were repainted by spraying with a conventional clearcoat, a two-component polyester / polyisocyanate coating composition, with the 1,6-hexamethylene diisocyanate trimer polyisocyanate (in a film thickness of 50-60 μm in a dry state). After curing for one day to room temperature, test boards 14-19 show a high gloss metallic coating. After one week up to room temperature, the water and solvent resistance of test boards 14-19 were excellent, compared to the test boards. The abrupt change of both the base coat and the base coat provided with clear coat was measured (see table 4). The values of abrupt change of the coatings of 'J < »« - «. "tMtJO., - * W - - * A * '"' ^ * «-« *.

Base coatings based on the coating compositions according to the invention are excellent, compared to the test boards A and B. The decrease of the abrupt change by applying the transparent coating (penetration) statically null, because a change is maintained brusque excellent. However, the abrupt change values of the basecoat / clearcoat of the air test boards are significantly lower showing a considerable penetration effect.

EXAMPLES 20-22 AND COMPARATIVE EXAMPLE C Basecoat compositions were prepared as follows. A mixture of 20 g of aluminum paste (65% by weight Aquavex Sparkle Silver E5000AR of Silberiine), 25.6 g of butoxyethanol, 30.2 g of Setal EPC 4673, 23.5 g of Cimel 328®, 97.8 g of water and 7.2 g of a 30% by weight solution of N, N-dimethyl ethanol in water was added with stirring to a mixture of 133.3 g of a polymer dispersion (I) according to examples 7-9, 90.7 g of water, and 13.3 g of a polymer dispersion (II) according to example 13. The base coating compositions were brought to a pH of 7.5-8.0 by the addition of N, N-dimethyl ethanol amine and diluted with water to spray the viscosity (time of efflux of 28 seconds in DIN Cup No. 4). The solids content was 20% by weight. The basecoat compositions were sprayed onto steel test boards in a film thickness of 12-18 μm (in the dry state). After a non-evaporating period of 2 minutes at 23 ° C and 8 minutes at 80 ° C, the test boards were repainted with a conventional clear micro-film at a film thickness of 40-45 μm in the dry state. The clear coat was one of the components called the polyacrylate / aminoplast coating composition. The aminoplast is a resin of the polymeric melamine type. After curing for 24 minutes at 140 ° C, a metallic coating of good appearance was obtained. The test boards were tested for moisture resistance compared to the reference base coat (Example 5 of EP-A-0 287 144, Comparative Example C). The moisture resistance of test panels 20 to 22 is excellent compared to the moisture resistance of test board C. Table 5 gives the results of the test.

TABLE 1 Compositions of monomers. ¿Sato * - ^ m ^^ n ^ n-- TABLE II Properties of polymeric dispersions of addition TABLE III Properties of rheology modifier dispersions TABLE IV Abrupt change values TABLE V Results of resistance to humidity

Claims (14)

NOVELTY OF THE INVENTION CLAIMS

1. An aqueous coating composition comprising a mixture of 90 to 99% by weight of a film-forming binder composition comprising a non-swelling core shell addition polymer dispersion (I), and 1 to 10% by weight weight of a dispersion of addition polymer (II) that modifies the rheology, the sum of the% by weight indicated for the film-forming binder composition and the dispersion (II) which is always 100% by weight, wherein the dispersion of the polymer (I) was prepared in two or more steps by the emulsion polymerization, and was obtained by copolymerization in a first step from (I) 60 to 95 parts by weight (calculated on 100 parts by weight of the total addition polymer (I) ) of a monomer mixture A consisting of 65 to 100 mol% of a mixture of (a) 10 to 98 mol% of a (cyclo) alkyl (meth) acrylate of which the cycloalkyl group contains from 4 to 12 atoms carbon, (b) from 0 to 55% molecular styrene, (c) from 2 to 15 mol% (metha) hydroxyalkyl acrylate, and (d) from 0 to 20% maleate and / or di (cyclo) alkyl fumarate of which the cycloalkyl group contains from 4 to 12 carbon atoms, sum of the molar% indicated for the monomers (a), (b), (c) and (d) is always 100 mol%, and (i) from 0 to 35 mol% of a different copolymerizable monoethylenically unsaturated monomer, the sum of the molar% indicated for components (i) and (ii) is always 100 mol%, and by copolymerization in a subsequent step of (2) 5 to 40 parts by weight (calculated on 100 parts by weight of the addition polymer total (I) of a monomer mixture B consisting of (e) 1 to 10 mol% of (meth) acrylic acid, (f) 2 to 20 mol% of hydroxyalkyl (meth) acrylate, (g) 0 to 55% molar styrene and (h) 15 to 97 molar% of a different monoethylenically unsaturated copolymerizable monomer, the sum of the molar% indicated for the monomers (e), (f), (g) and (h) is always 100 mol% , with groups of carboxylic acid (meth) acrylic acid derivatives being at least partially neutralized, resulting in a non-interlaced addition polymer I, whereby the total amount of (meth) acrylic acid in 100 parts of the total addition polymer (I) is less than 1.75% by weight, and wherein the dispersion of the polymer (II) was prepared by the emulsion polymerization, and was obtained by copolymerization of (ii) 99.5-99.99 parts by weight (of the total addition polymer (II )) of a monomer mixture C consisting of (j) 10 to 80% by weight (meth) acrylate (cyclo) alkyl, (k) 20 to 50% by weight (meth) acrylic acid, (m) 0 a 20% by weight (meth) hydroxyalkyl acrylate, and (n) 0 to 20% by weight of a different monoethylenically unsaturated copolymerizable the sum of% by weight indicated for the monomers (j), (k), (m) and ( n) is always 100% molar, and (iv) 0.01 to 0.05 parts by weight (calculated on 100 parts by weight of the total addition polymer (II )) of a compound having at least two unsaturated groups, the carboxylic acid groups derived from (meth) acrylic acid being at least partially neutralized.

2. - The aqueous coating composition according to claim 1, further characterized in that the monomer mixture A consists of (i) 80 to 100 mol% of a mixture of (a) 30 to 95 mol% of a (meth) acrylate of (cyclo) alkyl of which the (cyclo) alkyl group contains from 4 to 12 carbon atoms, (b) 0 to 50 mol% styrene, (c) 5 to 12 mol% hydroxyalkyl (meth) acrylate, and (d) 0 to 8 mol% of maleate and / or di (cyclo) alkyl fumarate of which the (cyclo) alkyl group contains from 4 to 12 carbon atoms, and (i) 0 to 20 mol%, preferably 0 % molar, of a different copolymerizable monoethylenically unsaturated monomer.

3. The aqueous coating composition according to any of the preceding claims, further characterized in that the monomer mixture B consists of (e) 5-8 mole% of (meth) acrylate acid, (f) 5-12 mol% of hydroxyalkyl (meth) acrylate, (g) 0-30 mol% of styrene, and (h) 50-90 mol% of a different copolymerizable monoethylenically unsaturated monomer.

4. The aqueous coating composition according to any of the preceding claims, further characterized in that the total amount of (meth) acrylic acid in 100 parts of the total addition polymer (I) is between 0.5 and 1.4% by weight.

5. The aqueous coating composition according to any of the preceding claims, further characterized in that the monomer mixture C consists of (j) 50-70% by weight of (cyclo) alkyl (meth) acrylate (k). -40% by weight of (meth) acrylic acid, (m) 0-5% by weight of hydroxyalkyl (meth) acrylate, and (n) 0-5% by weight of a different copolymerizable monoethylenically unsaturated monomer.

6. The aqueous coating composition according to any of the preceding claims, further characterized in that the polymer dispersion (II) was prepared by the emulsion polymerization of (ii) 99.5-99.99 parts by weight of the monomer C mixture. and (iv) 0.05 to 0.15 parts by weight of a compound having at least two unsaturated groups.

7. An aqueous coating composition according to any of the preceding claims, further characterized in that the compound has at least two unsaturated groups having at least one allylic group.

8. The aqueous coating composition according to claim 7, further characterized in that the compound has at least two unsaturated groups were selected from diallyl phthalate, diaryl methacrylate and triallyl socianurate.

9. An aqueous coating composition according to any of the preceding claims, further characterized in that the film-forming binder composition can comprise, in addition to the alkali (I) alkaline-non-swelling core polymer addition dispersion. a material dilutable in water.

10. The aqueous coating composition according to claim 9, further characterized in that the composition The film-forming binder may comprise 0.1 to 99.9% by weight of the alkali-non-swellable alkali (I) core polymer addition dispersion and 99.9 to 0.1% by weight of at least one water-dilutable material, wherein the sum of the% by weight indicated for the dispersion (I) and the water-dilutable materials are always 100% by weight.

11. The aqueous coating composition according to claim 9 and 10, further characterized in that the water-dilutable material was selected from alkyd resins, polyesters, polyurethanes and mixtures thereof.

12. The aqueous coating composition according to claim 11, further characterized in that the water-dilutable material is polyurethane.

13. A basecoating composition comprises an aqueous coating composition according to any of the preceding claims.

14. The use of a base coating composition according to claim 13, in the refining of automobiles, the finishing of trucks, buses, trains, airplanes and the finishing of automobiles. * - ȣ &. *