NL8304021A - Aq. polymer dispersion stabilised with ionised carboxylic polyester - from acid anhydride and polyester - Google Patents

Abstract

Aq. dispersion of a polymer of 1 or more alkenically unsatd. cpds. is stabilised by a ionised carboxylic polyester with acid number 40-150, PH number 0-150, and Mn 500-10,000. The polyester is the adduct of a 4-17C polycarboxylic acid anhydride and an initial satd. polyester from a 2-9C di- or poly-OH cpd. and a 2-40C di- or poly-carboxy cpd. with OH number 20-200. The binder in the dispersion consists of 1-99 wt.% of the polymer and 99-1% of the carboxylic polyester.

Description

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ACO 1913

Stable aqueous dispersion of a polymer as well as the preparation and use of such a dispersion.

The invention relates to an aqueous dispersion of a polymer of one or more olefinically unsaturated compounds.

One of the objects of the invention is to provide an aqueous polymer dispersion, the dispersed polymer of which has a very small particle size, for example a particle size of 30-400 nm, preferably of 50-200 nm. On the basis of this polymer dispersion, a physically drying or powder coating coating composition can be prepared. After drying of the polymer dispersion, a coating with a very high gloss is obtained, which has a good external durability and resistance to water and moisture. Another advantage is that the polymer dispersion has a low viscosity.

The aqueous dispersion according to the invention is now characterized in that the dispersion is stabilized with an ionized carboxylic polyester with an acid number of 40-150, a hydroxyl number of 0-150 and a number average molecular weight of 500-10000 and which polyester is the adduct of a polycarboxylic anhydride of 4-17 carbon atoms on a saturated starting polyester built up of a bivalent or superior hydroxy compound of 2-9 carbon atoms and a bivalent or polyvalent carboxyl compound of 2-40 carbon atoms and of a hydroxyl number of 20-200 wherein the binder of the dispersion is 1-99% by weight of the polymer of one or more olefinically unsaturated compounds and 1-99% by weight of the carboxylic polyester.

The starting polyester can be prepared according to the invention by polycondensation of one or more aliphatic and / or cycloaliphatic bivalent or polyhydric hydroxy compounds with 2-9 carbon atoms and, if desired, monovalent hydroxy compounds with one or more aliphatic, cycloaliphatic and / or aromatic bivalent or polyvalent carboxyl compounds of 2-40 carbon atoms and optionally monovalent carboxyl compounds, including derivatives of such hydroxy or carboxylic compounds such as epoxy compounds, esters, acid anhydrides or acid chlorides.

Suitable bivalent or polyhydric hydroxy compounds of 2-9 carbon atoms include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 2,2-dimethylpropanediol-1,3, propylene oxide, 2-methyl-2-propylpropanediol 1,3f 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,2,4-trimethylpentanediol-1,3,2,4,4-trimethylhexanediol-1,6,4,4, 4-triraethylhexanediol-1,6, dimethylol-propionic acid, the neopentyl glycol ester of hydroxypivalic acid (Esterdiol 10 204), pentanediol-1,5, hexanediol-1,6, 2-ethylhexanediol-1,6, 1,4-dimethylolcyclohexane, 1,4-dihydroxycyclohexane, glycerol, 2,3-epoxy-1-propanol, triraethylol ethane, trimethylol propane, pentaerythritol and sorbitol. Divalent or trivalent hydroxy compounds with 2-7 carbon atoms are used, in particular dihydroxy compounds with 2-6 carbon atoms, such as ethylene glycol, propylene glycol-1,2, pentanediol-1,5 or hexanediol-1,6. Suitable monovalent hydroxy compounds include benzyl alcohol, lauryl alcohol, octyl alcohol, linoleyl alcohol, steryl alcohol and cetyl alcohol.

Suitable bivalent or polyvalent carboxyl compounds include oxalic acid, malonic acid, succinic acid or its anhydride, glutaric acid, adipic acid, azelaic acid, trimethyladipic acid, sebacic acid, dimerized fatty acids, hexahydrophthalic acid, o-phthalic acid or its anhydride, dichlorophthalic acid , terephthalic acid, dimethyl terephthalate, methyl orthohexahydrophthalic acid, trimellitic acid or its anhydride, and pyromellitic acid. Preferably a (cyclo) aliphatic or aromatic di- or tricarboxylic acid with 2-12 carbon atoms or the anhydride thereof is used. Suitable monovalent carboxylic compounds include valeric acid, heptanoic acid, 2-ethylhexanoic acid, pelargonic acid, isonanoic acid, lauric acid, palmitic acid, stearic acid, cerotinic acid, cyclo-pentanecarboxylic acid, cyclopentanopropionic acid, cyclohexanecarboxylic acid, benzoic acid and p-benzoic acid.

The polycondensation reaction to prepare the starting polyester is usually conducted at a temperature of 140 ° -300 ° C, preferably at 180 ° -260 ° C, and in an inert atmosphere of, for example, nitrogen and / or carbon dioxide. The water released during the polycondensation can be removed in a conventional manner, for example by distillation under reduced pressure or by azeotropic distillation using an organic solvent, for example toluene or xylene. These solvents can, if desired, be removed from the polyester resin after the end of the polycondensation by distillation.

The polycondensation reaction is continued until the starting polyester has the required hydroxy value of 20-200 and preferably of 35-130. The acid number of the starting polyester is preferably at most 5, more particularly 0-3. The acid number and the hydroxy number are expressed in mg KOH per g of starting polyester.

If desired, an esterification catalyst may be present in the polycondensation mixture, for example sulfuric acid, p-toluenesulfonic acid, benzenesulfonic acid, naphthalenesulfonic acid, a sulfonic acid cation exchanger or a metal compound, for example dibutyltin dilaurate or lead acetate, preferably dibutyltin oxide.

The number average molecular weight of the starting polyester is preferably 800-3800.

The adduct according to the invention of a polycarboxylic anhydride with 4-17 carbon atoms and the starting polyester described above can be effected in any suitable manner known per se, for instance by melting the starting polyester or optionally dissolving it in a suitable inert solvent and then to be mixed with the appropriate polycarboxylic anhydride. The reaction mixture is usually heated at a temperature of generally 100 ° -220eC, preferably 120e-170eC, until the adduct formed has the desired acid number.

Suitable polycarboxylic anhydrides include anhydrides of dicarboxylic acids such as phthalic acid, 3-sulfonyl phthalic acid, nitrophthalic acid and acetyl phthalic acid; tricarboxylic acids such as trimellitic acid and tetracarboxylic acids such as pyromellitic acid. Anhydrides of di- or tricarboxylic acids with 4-10 carbon atoms are preferably used.

Preferably, the carboxylic polyester has an acid number of 45-75, a number average molecular weight of 1000-4000 or a hydroxyl number of 0-120.

The invention also relates to a process for the preparation of an aqueous dispersion of a polymer of one or more olefinically unsaturated compounds, stabilized with a carboxylic polyester stabilized aqueous polymer. parts by weight of the olefinically unsaturated compound (s) polymerizes by means of a radical initiator in the presence of 99-1 parts by weight of an ionized carboxylic polyester 5 with an acid number of 40-150, a hydroxyl number of 0-150 and a number average molecular weight of 500-10000 and which polyester is the adduct of a polycarboxylic anhydride of 4-17 carbon atoms to a saturated starting polyester built up of a bivalent or polyhydric compound of 2-9 carbon atoms and a bivalent or polyvalent carboxyl compound of 2-40 carbon atoms and with a hydroxyl number of 20-200.

Suitable examples of olefinically unsaturated compounds which can be polymerized according to the process according to the invention into a polymer dispersed in an aqueous phase include the mono-, di- or poly (meth) acrylic acid esters of mono- or polyhydric alcohols with 15 1 to 18 carbon atoms, for example the (meth) acrylic acid esters of methanol, ethanol, propanol, n-butanol, butanol-2, 2-ethylhexanol, dodecyl alcohol, hexadecyl alcohol, ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, 1, 4-dihydroxycyclohexane, glycerol, trimethylol ethane, trimethylol propane, pentaerythritol and dipentaerythritol; nitrile-20s, for example, acrylonitrile and methacrylonitrile; vinyl aromatic compounds such as styrene, α-methylstyrene and divinylbenzene; and compounds such as vinyl chloride, vinyl acetate, vinyl propionate, vinylidene fluoride, vinylidene chloride, butadiene-1,3, isoprene, chloroprene, vinyl acrylate, and the methyl ether of methyl acrylate glycolate. Mixtures of 25 monomers are applicable. Preferably, a mixture of one or more mono-olefinically unsaturated compounds and 0-30, more particularly 0-15, wt.%, Based on the total mixture, of one or more di-or polyolefinically unsaturated compounds is used. Usually so much of a hydroxyl group-containing monomer is used that the poly-30 produced has a hydroxyl number of 0-150, preferably 0-120. The polymer generally has a number average molecular weight of 50000-250000 and a second order glass transition point (Tg) between -40 ° and + 70® C.

The polymerization can take place according to methods known per se, using a free-radical initiator at a temperature of 8304021.

X

ACO 1913 generally at most 180 ° C, preferably 20-150 ° C. Suitable free-radical initiators include peroxides such as di-tert. butyl peroxide, benzoyl peroxide; hydroperoxides such as tert. butyl hydroperoxide, cumene hydroperoxide / cyclohexanone hydroperoxide? and compounds such as hydrogen peroxide and N, N * bisazoisobutyronitrile and persalts such as potassium per sulfate.

The initiator or a mixture of initiators is usually used in an amount of 0.05-7% by weight, preferably 0.2-3% by weight, based on the amount of olefinically unsaturated monomer.

Preferably, the aqueous dispersion contains 5-60 parts by weight of the carboxylic polyester and 40-95 parts by weight of the polymer of one or more olefinically unsaturated compounds.

The invention polymerizes the olefinically unsaturated compound (s) in the presence of the ionized carboxylic polyester.

Suitable basic compounds to ionize the carboxylic polyester include inorganic hydroxides, for example, ammonia or lithium hydroxide, or primary, secondary or tertiary amines, for example, monoethylamine, monobutylamine, dimethylamine, dimethylethanolamine, diethyl amine, diethanol amine, methhanol amine -20 ethanolamine, or mixtures of two or more of the compounds referred to herein. It is usually not necessary that all of the carboxyl groups of the polyester be neutralized to obtain sufficient ionization of the polyester. Practically, 30-100%, preferably 60-100%, of the carboxyl groups are neutralized. The pH of the solution is usually 4 1 / 2-8 1/2, preferably 5 1 / 2-7.

The aqueous dispersion according to the invention can be applied in many areas, for example as a physically drying coating composition or as a stove-enameled composition in the form of a so-called "coil coating" or, for example, in the automotive sector.

When the aqueous dispersion is used as the basis for a stoving coating composition, the binder of the aqueous dispersion should have a hydroxyl number of 40-150, preferably of 60-120 and the 8304021 - 6 - ACO 1913 composition also contains a hardener for the binder. Common cross-linking agents generally include N-raethylol and / or N-methylol ether group-containing aminoplasts obtained by reacting an aldehyde / e.g. formaldehyde with an amino or amido group-containing compound such as melamine, urea, Ν, Ν'- ethylene urea, dicyandiamide and benzoguanamine; for the preparation of such compounds see, for example, Houben-Weyl, Methods of Organic Chemistry; Vol. 14/2, pp. 319-371 (1963). Preferably, the above-described compounds are fully or partially etherified with alcohols having 1 to 6 carbon-10 atoms, for example, with methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, amyl alcohol, hexanol or mixtures of the aforementioned alcohols . In particular, a methylol melamine having 4 to 6 methylol groups per molecule of melamine is used, wherein at least 3 methylol groups are etherified with methanol, ethanol, a propanol or with a butanol, or a condensation product of formaldehyde and N, N 'etherified with a butanol. ethylene diurea. More in particular, a hexaalkoxymethylmelamine is used, wherein the alkoxy group contains 1 to 4 carbon atoms. Instead of or in addition to the above-described curing agents, other suitable agents may be used, for example, blocked or unblocked isocyanurate compounds or blocked or unblocked, aliphatic, cycloaliphatic or aromatic bivalent, trivalent or polyvalent isocyanates.

Suitable isocyanates are, for example, hexaraethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate-1,6,4,4,4-triraethylhexane diisocyanate-1,6, cyclohexane-1,4-diisocyanate, isophorone diisocyanate, the adduct of 1 molecule of butanediol-1. 4 and 2 molecules of isophorone diisocyanate, the adduct of 1 molecule of butanediol-1,4 and 2 molecules of hexamethylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, xylylene diisocyanate, 1,3,5-trimethyl-2,4-bis (isocyanatomethyl) benzene, toluene diisocyanate, 30 diphenylmethane-4,41-diisocyanate, the adduct of 3 molecules of hexaraethylene diisocyanate and 1 molecule of water, the adduct of 1 molecule of triraethylolpropane and 3 molecules of isophorone diisocyanate, the adduct of 1 molecule of trimethylolpropane and 3 molecules of toluene diisuct 1 molecule of pentaerythritol and 4 molecules of hexaraethylene diisocyanate.

For blocking the isocyanate or isocyanurate compound, any conventional or suitable blocking agent can be used for this.

8304021 - 7 - ACO 1913

The curing agent 1 is present in the coating composition in an amount such that the molar ratio of the reactive groups of the cross-linking agent to that of the hydroxyl group-containing polymer is between 0/6 and 1/5 and preferably between 0.7 and 1.3.

The coating composition may optionally contain one or more pigments, dyes and customary auxiliaries, additives and solvents, for example, pigraent dispersants, thixotropy promoters, theological property influencing agents, plasticizers, matting agents, and compounds promoting the hardening reaction, such as p- toluene sulfonic acid or blocked products of such accelerators. Applicable pigments include the usual types, namely acidic, neutral or basic pigments, which may be organic or inorganic in nature. If desired, the pigments can be pretreated to modify the properties. Suitable pigments include titanium dioxide, iron oxide red, lead chromate, carbon black, and phthalocyanine pigments. The term pigments also includes metallic pigments, such as aluminum and stainless steel. The weight ratio of pigment to the total binder is generally between 0 and 0.8 and preferably between 0 and 0.7.

Suitable sara liquids include 2-ethylhexanol and the butyl ethers of ethylene glycol and diethylene glycol.

The coating composition can be applied to the substrate in any suitable manner, for example by (electrostatic) spraying, brushing, pouring, dipping or with the roller, in one or more layers, but another method of application, for example electrophoresis, is of course also possible. The substrate can be, for example, a metal or an alloy, a plastic, an elastomer, wood, glass, etc.

The invention is further illustrated by the following examples. By "parts" herein is meant "parts by weight" and "%" herein means "weight 30 percent."

83 04 0 2.1 - 8 - A CO 1913

Preparation (ionized) carboxylic polyesters

Example A

In a reactor equipped with a stirrer, a thermometer and a water outlet, 2689 drops of pentanediol-1/5, 6.5 parts of di-5-butyltinoxide, 3728 parts of isophthalic acid and 210 g of xylene are mixed together, and the mixture is then heated to a temperature of 230 ° C with azeotropic removal of the water formed until the acid value of the mixture is less than 2.

The prepared hydroxy polyester is then cooled to a temperature of 150 ° C and mixed with 642 parts of trimellitic anhydride. The temperature of the mixture is kept at 150 ° C until the acid number of the obtained carboxylic polyester A is 60-62.

Example B

The method of preparation of Example A is repeated, however, using the components in the following amounts: 2195 parts of pentanediol-1.5, 5.5 parts of dibutyltin oxide, 3261 parts of isophthalic acid and 545 parts of trimellitic anhydride. The carboxylic polyester B prepared had an acid number of 60-62.

Example C

Example B was repeated, but using 232 parts of propylene glycol-1,2 and 720 parts of hexanediol-1,6, 3.2 parts of dibutyltin oxide, 1228 parts of adipic acid and 227 parts of trimellitic anhydride. A carboxylic polyester C with an acid number of 61.5 was obtained.

Example D

Example B was repeated, however, using 210 parts of pentanediol-1,2, 6.0 parts of dibutyltin oxide, 1176 parts of isophthalic acid and 461 parts of trimellitic anhydride. A carboxylic polyester D with an acid number of 122 and a hydroxyl number of about 0 was obtained.

8304021 - 9 - ACO 1913

Example E

1262 parts of the polyester prepared according to Example A were heated to a temperature of 85 ° -90 ° C, after which 116 parts of dimethylethanolaraine were added with stirring for 15 minutes. Then, 5 1121 parts of deionized water were added and the resulting dispersion was homogenized.

Example F

Example E was repeated, but using 150 parts of the polyester prepared according to Example C, 18 parts of diraethylethanolamine and 10 500 parts of deionized water.

Example G

Example E was repeated, but using 125 parts of the polyester prepared according to Example D, 32 parts of methyl diethanolamine and 500 parts of deionized water.

Example H

Example E was repeated, however, using 400 parts of the polyester prepared according to Example B, 37 parts of dimethylethanolamine and 300 parts of deionized water.

Example 1 300 parts of the polyester solution obtained according to Example E and 350 parts of deionized water were mixed together in a polymerization reactor. 5.0 parts of a 70% tert dispersion were added to the mixture. butyl hydroperoxide in water was added and the whole was brought to a temperature of 100 ° C. At this temperature, 260 parts of butyl methacrylate and 90 parts of hydropropyl methacrylate were added with stirring for 2 1/2 hours and then the reaction was continued for 1/2 hour. A polyacrylate latex with a solids content of 41%, a particle size of 80-200 nm and a viscosity of 59 seconds was obtained.

8304 0 2 1,. w * - 10 - ACO 1913

Example 2

The polyester solution obtained according to Example F was heated to a temperature of 90 DEG-100 DEG and a mixture of 260 parts of butyl methacrylate, 90 parts of hydroxypropyl methacrylate and 10.0 parts of benzoyl peroxide was then added with stirring for 2 1/2 hours. The reaction was then continued at a temperature of 95 ° C for 40 minutes. A polyacrylate latex with a solids content of 49%, a particle size of 60-250 nm and a viscosity of 47 seconds was obtained.

10 Example 3

Example 1 was repeated, however, using the polyester solution obtained according to Example G, 2 parts of potassium persulfate and 375 parts of butyl methacrylate. A polyacrylate latex with a solids content of 49.8%, a particle size of 40-70 nm and a viscosity of 72 seconds was obtained.

Example 4

In a polymerization reactor, the polyester solution obtained according to Example H was mixed with 2.2 parts of potassium persulfate and the whole was brought to a temperature of 75e-80 ° C. At this temperature, 300 parts of styrene were added over 3 hours with stirring, and the reaction was then continued for 1 hour. A polystyrene latex with a solid content of 60-140 nm and a viscosity of 62 seconds was obtained. The latex, after being stored at room temperature for 8 months, showed no sign of destabilization. 1 8304021

All latices prepared according to the Examples were applied to an aluminum panel in a layer thickness of 70-75 µm (in the dry state). After drying, the coating layer exhibited a gloss of 85-93% at an angle of 60 °.

Claims (12)

11. ACO 1913 An aqueous dispersion of a polymer of one or more olefinically unsaturated compounds, characterized in that the dispersion is stabilized with an ionized carboxylic polyester 5 with an acid number of 40-150, a hydroxyl number of 0-150 and a number average molecular weight of 500 -10000 and which polyester is the adduct of a polycarboxylic anhydride with 4-17 carbon atoms to a saturated starting polyester built up of a bivalent or polyvalent hydroxy compound with 2-9 carbon atoms and a bivalent or polyvalent carboxyl compound with 2-40 carbon atoms and with a hydroxyl number from 20-200, where the binder of the dispersion exists for 1-99 wt. % from the polymer of one or more olefinically unsaturated compounds and from 1 to 99% by weight from the carboxylic polyester. Polymer dispersion according to claim 1, characterized in that the starting polyester is composed of a bivalent or trivalent hydroxy compound with 2-7 carbon atoms. Polymer dispersion according to claim 1 or 2, characterized in that the starting polyester is composed of a (cyclo) aliphatic or aromatic di- or tricarboxylic acid with 2-12 carbon atoms or the anhydride thereof. Polymer dispersion according to claim 1, characterized in that the starting polyester has a hydroxyl number of 35-130. Polymer dispersion according to claim 1, characterized in that the starting polyester has an acid number of at most 5. Polymer dispersion according to claim 1, characterized in that the starting polyester has a number average molecular weight of 800-3800. 1 2 8304021 Polymer dispersion according to claim 1, characterized in that the carboxylic polyester is the adduct of an anhydride of a V> 12. ACO 1913 di- or tricarboxylic acid with 4-10 carbon atoms and the starting polyester. Polymer dispersion according to claim 1, characterized in that the carboxylic polyester has an acid number of 45-75, a number average molecular weight of 1000-4000 or a hydroxyl number of 0-120. Polymer dispersion according to claim 1, characterized in that the polymer of one or more olefinically unsaturated compounds is prepared by polymerizing a mixture of one or more mono-olefinically unsaturated compounds and 0-30 wt. %, based on the total mixture, of one or more di- or polyolefinically unsaturated compounds. Polymer dispersion according to claim 9, characterized in that the polymer has a hydroxyl number of 0-150. A process for the preparation of a carboxylic polyester-stabilized aqueous dispersion of a polymer of one or more olefinically unsaturated compounds, polymerizing 1-99 parts by weight of the olefinically unsaturated compound (s) in a free-radical initiator in content of 99-1 parts by weight of an ionized carboxylic polyester with an acid number of 40-150, a hydroxyl number of 0-150 and a number average molecular weight of 500-10000 and which polyester is the adduct of a polycarboxylic anhydride with 4-17 carbon atoms on a saturated starting polyester composed of a bivalent or polyhydric hydroxy compound of 2-9 carbon atoms and a bivalent or polyvalent carboxyl compound of 2-40 carbon atoms and of a hydroxyl number of 20-200. 1 8304021 Physically drying or stovable coating cora position based on the aqueous polymer dispersion according to any one of claims 1-10.