CA1230443A - Process for the preparation of an aqueous copolymer dispersion and the use of the dispersion - Google Patents
Process for the preparation of an aqueous copolymer dispersion and the use of the dispersionInfo
- Publication number
- CA1230443A CA1230443A CA000407389A CA407389A CA1230443A CA 1230443 A CA1230443 A CA 1230443A CA 000407389 A CA000407389 A CA 000407389A CA 407389 A CA407389 A CA 407389A CA 1230443 A CA1230443 A CA 1230443A
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- esters
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D125/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Coating compositions based on derivatives of such polymers
- C09D125/02—Homopolymers or copolymers of hydrocarbons
- C09D125/04—Homopolymers or copolymers of styrene
- C09D125/08—Copolymers of styrene
- C09D125/14—Copolymers of styrene with unsaturated esters
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/08—Anhydrides
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/10—Esters
- C08F220/12—Esters of monohydric alcohols or phenols
- C08F220/14—Methyl esters, e.g. methyl (meth)acrylate
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
- C09D133/04—Homopolymers or copolymers of esters
- C09D133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
- C09D133/062—Copolymers with monomers not covered by C09D133/06
- C09D133/066—Copolymers with monomers not covered by C09D133/06 containing -OH groups
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
- C08L61/20—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen
Abstract
Abstract of the disclosure An aqueous copolymer dispersion can be prepared, with a particular choice of the monomers and the ratios of their amounts, from styrene, esters of acrylic or meth-acrylic acid, vinyl esters, monomers containing hydroxyl groups, acrylic and/or methacrylic acid, acryl-amide or methacrylamide and addition compounds of gly-cidyl esters of branched monocarboxylic acids with unsatu-rated carboxylic acids, by polymerization in the presence of an anionic emulsifier and a radical initiator and, if appropriate, a non-ionic emulsifier, which dispersion , in combination with an aminoplast resin, provides thermosetting coatings with excellent properties. These coatings provide highly elastic, weather-resistant, water-resistant surface coatings, which have high adhesion and are free of flaws, on metallic substrates.
Description
31,;~3~4~L3 2 - ~10~ 81~F 172 The invent;on relates to a process for the preparat;on of an aqueous copolymer dispersion and the use of th;s d;spersion for the preparation of coatings ~hich can be crosslinked by the action of heat (thermosetting coatings~.
S Aqueous copolymer dispersions are o~ part;cuLar interes~ for the preparat;on of thermosetting coatings, because they are not flammable and they are less physio-logically objectionable than coating agents containing sol-- vents. Furthermore, there is no necessity to recover a costly solvent. In add;tion to the properties wh;ch are requ;red o~ all plastics dispersions~ such as a good flo~
behavior, good processability, freedom from coagulation, storaQe and heat stability~ it ;s also particularly impor~-ant for copolymer dispersions ~hich are to be used as bind-ers for the preparation of thermosetting co3tings thatcoating agents are s~tained which level ~ell and adhere uell, ~hich dry even at room temperature and ~hich shc~ no crac~s or other irregularit;es ;n the f;lm. The coat;ngs obtained from these should then be curabLe by heat treat~
ment~ For this purpose, the copolymers on ~h;ch the dis-persions are based have reactive groups in the molecule which react w;th the reactive groups of certain resins, in par-t;rular am;noplast res;ns~ so that the binder crossl;nks.
In addit;on to the advantages such as, for example, low v;scos;ty at a hi~h content of sol;ds, high molecular ueight and the absence of volat-le solvents, aqueous co-polymer dispers;ons also have disadvantages for thermo-setting coat;ngs such asf for example~ a lack Qf pigment ~etting~ de~;cient adhesion to the substrate, poor level;nq .~ ~
1~3~
of the co2ting agents manufactured using this dispersion and 1nadequate elasticity of the baked films, but particu~arly ~o~ gloss and lo~ resistance to water.
In a test method~ ~hicn is frequently used in pa;nt technology, the lacquer film, which has been sprayed onto metallic substrates and baked in an oven heated by circu-! lat;ng air, is tested ~ith a moist wad of absorbent cottonand the t;me necessary for the lacquer film to s~ell and so~ten, unt;l it can be damaged by simple mechanical stress (for example scratch;n~ ~;th a spatula~, ;s measuredu A
good bak;ng varnish is expected to have ~ater-resistance values by this method ~h;ch are in the order of magn;tude of 800 hours ~about 1 month).
The addition of leveling agents t"con~luence ~5 agents", coalescence agents) to thermosetting coating agents, ~h;ch contain as the binder aqueous dispersions based on acrylic poly'mers, to improve the leveling~ is known tcf. German Offenle~ungschriften 2,211,16~,
S Aqueous copolymer dispersions are o~ part;cuLar interes~ for the preparat;on of thermosetting coatings, because they are not flammable and they are less physio-logically objectionable than coating agents containing sol-- vents. Furthermore, there is no necessity to recover a costly solvent. In add;tion to the properties wh;ch are requ;red o~ all plastics dispersions~ such as a good flo~
behavior, good processability, freedom from coagulation, storaQe and heat stability~ it ;s also particularly impor~-ant for copolymer dispersions ~hich are to be used as bind-ers for the preparation of thermosetting co3tings thatcoating agents are s~tained which level ~ell and adhere uell, ~hich dry even at room temperature and ~hich shc~ no crac~s or other irregularit;es ;n the f;lm. The coat;ngs obtained from these should then be curabLe by heat treat~
ment~ For this purpose, the copolymers on ~h;ch the dis-persions are based have reactive groups in the molecule which react w;th the reactive groups of certain resins, in par-t;rular am;noplast res;ns~ so that the binder crossl;nks.
In addit;on to the advantages such as, for example, low v;scos;ty at a hi~h content of sol;ds, high molecular ueight and the absence of volat-le solvents, aqueous co-polymer dispers;ons also have disadvantages for thermo-setting coat;ngs such asf for example~ a lack Qf pigment ~etting~ de~;cient adhesion to the substrate, poor level;nq .~ ~
1~3~
of the co2ting agents manufactured using this dispersion and 1nadequate elasticity of the baked films, but particu~arly ~o~ gloss and lo~ resistance to water.
In a test method~ ~hicn is frequently used in pa;nt technology, the lacquer film, which has been sprayed onto metallic substrates and baked in an oven heated by circu-! lat;ng air, is tested ~ith a moist wad of absorbent cottonand the t;me necessary for the lacquer film to s~ell and so~ten, unt;l it can be damaged by simple mechanical stress (for example scratch;n~ ~;th a spatula~, ;s measuredu A
good bak;ng varnish is expected to have ~ater-resistance values by this method ~h;ch are in the order of magn;tude of 800 hours ~about 1 month).
The addition of leveling agents t"con~luence ~5 agents", coalescence agents) to thermosetting coating agents, ~h;ch contain as the binder aqueous dispersions based on acrylic poly'mers, to improve the leveling~ is known tcf. German Offenle~ungschriften 2,211,16~,
2,252,065, 2,416,446 and 2,505,829 - U.S. Patents
3,962,167, 4,020,219, 4,132,688, 3,904,7~5 and 4,137,205~.
These agents ~ssist the flowing together of the coat;ng during dry;ng in a;r before bak;ng. The follow;ng are used: long-chain alcohols, d;methylformam;de, tributyi phosphate~ polyethylene or polypropylene glycols~ 2-butoxy-ethanol acetateO diacetone alcohol, 3,5,5-trimethyl-2-cyclohexen-1-one~ caprolac~am, addition products of poly-hydr;c alcohols ~ith C2 to C4 epox;des or d;ssolved and compatible cooolymer resins.
The d;sadvantage of the add;t;ves ~entioned is uC r ~rl that there are adverse effects, not only on the gloss and level-ing, but also on other technological properties of the films due to the hydrophilic and low molecular weight additives. In part-icular, -the resistance to water and chemicals oE -the baked coatings suffer adverse effects.
~ ccording to the German OfEenlegungsschrift 2,709,308, specifically for improving the water-resistance of coatings which have been prepared using dispersions of thermosetting copolymers, in the preparation of the dispersions, alkali metal or alkaline earth metal ions, for example from initiators and emulsifiers, should be replaced by ammonium ions. ~Iowever, even with dispers-ions of this type, water-resistances of only about 120 hours are achieved.
The object of the invention is to make an aqueous dispersion of a copolymer which can be crosslinked with an amino-plast resin by the action of heat and which leads to coatings which have good levelling and are free of flaws, and which, in particular, are water-resistant, on metallic substrates.
It has been found that aqueous copolymer dispersions can be prepared, with a particular choice of the monomers and the ratios of their amounts, from styrene, esters of acrylic or methacrylic acid, vinyl esters, monomers containing hydroxyl groups, acrylic and/or methacrylic acid, acrylamide and/or metha~
crylamide and addition compounds of glycidyl esters of branched monocarboxylic acids with unsaturated carboxylic acids, by polymerization in the presence of an anionic emulsifier and a ~ - 'L -~236~4~3 radical initiator and, if appropriate, a non-ionic emulsifier, which dispersions, in combination with aminoplas-t resins, provide thermosetting coatings with excellent properties. These coatings provide highly elastic, wea-ther-resistant, water-resistant surface coatings, which have high adhesion and are free of flaws, on metallic substrates.
Thus, the invention relates to a process for the prepara-tion of an aqueous dispersion of a copolymer which can be cross-linked with an aminoplast resin by the action of heat and which is prepared by copolymerization of monomers from the group comprising styrene, esters of acrylic acid, esters of methacrylic acid, vinyl esters, monoolefinic unsaturated monomers having hydroxyl groups, acrylic acid, methacrylic acid, unsaturated amides and other functional comonomers, in an aqueous phase in the presence of a radical-forming initiator and an anionic emulsifier, which com prises copolymerizing a mixture of 30 to 60 parts by weight of styrene and/or methyl meth-acrylate, 20 to 50 parts by weight of an ester of acrylic acid or of methacrylic acid, the homopolymer of which has a glass tempera-ture TG below +50C, or a mixture of these esters, 5 to 30 parts by weight of a vinyl ester of a branched saturated monocarboxylic acid, which has side chains having 8 to 12 carbon atoms and in which the carboxyl group is on a tertiary carbon atom, 5 to 15 parts by weight of a hydroxyalkyl ester of a mono-., , ~3~3 olefinic unsaturated monocarboxylic acid, 0.5 to 15 parts by weight of an ~ unsaturated mono-carboxylic acid and/or unsaturated dicarboxylic acid, 0.1 to 8 parts by weight of an addition product of a glycidyl ester of a branched monocarboxylic acid with an unsaturat-ed monocarboxylic or dicarboxylic acid, and 0.1 to 5 parts by weight of an unsaturated amide.
The invention also relates to the use of the copolymer dispersion, prepared in this manner, for -the manufacturing of coat-ings which can be crosslinked by the action of heat.
30 to 60, preferably 35 to 55, parts by weight of styrene and/or methyl methacrylate are employed as the monomers which serve as the "hardening" component. Methyl methacrylate is preferably employed.
The mixture of monomers to be employed contains as the "plasticizing" component 20 to 50, preferably 25 to 45, parts by weight of an ester of acrylic acid or of methacrylic acid, the homopolymer of which has a glass temperature TG below +50C, or mixtures o~ these esters. Examples of these monomers are ethyl, acrylate, propyl acrylate, isopropyl acrylate, and n- and i-butyl, 2-ethylhexyl and decyl acrylates and methacrylates.
Furthermore, the mixture of monomers to be employed con-tains 5 to 30, preferably 8 to 26, parts by weight of a vinyl ester of a bxanched saturated monocarboxylic acid which has side chains having 8 to 12 carbon atoms and the carboxyl group on a tertiary ~2~ 3 carbon atom. This type of carboxylic acid can be obtained by Koch's method of synthesis from olefins, carbon monoxide and water.
The vinyl ester of a branched satura-ted monocarboxylic acid having a total oE 10 carbon a-toms, the carboxyl group of which is on a tertiary carbon atom, is preferably used.
In order to achieve an adequate reactivity of the coat-ing mixture to be manufactured from the dispersion, an additional monomer employed, in an amount of 5 to 15, preferably 6 to 12, parts by weight, is a hydroxyalkyl ester of a monoolefinic un-saturated monocarboxylic acid, for example hydroxyethyl acrylate, 2-hydroxypropyl acrylate, hydroxyethyl me-thacrylate, 2-hydroxy-propyl methacrylate, 4-hydroxybutyl methacrylate, glycerol mono-methacrylate, trimethylolpropane monoacrylate, reaction products cf hydroxyethyl methacrylate with 2-8 moles of ethylene oxide, neopentylglycol monomethacrylate and triethylene glycol monoacry-late.
The incorporation of unsaturated monocarboxylic acids in-to the copolymer increases the stability of the dispersion during manufacture, storage and use. ~igh shear forces occur particularly for industrial lacquers during the manufacture and application of the coating agents. For this reason, the mixture of monomers to be employed contains 0.5 to 10, preferably 1 to 8, parts by weight of an a,~-unsaturated monocarboxylic acid and/or an unsaturated di-carboxylic acid~ Suitable acids are acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid and itaconic acid.
~crylic acid and/or methacrylic acid are preferably used.
In addition, the mixture of monomers to be employed con-, ~
~2~
tains 0.1 to 8, preferably 1 to 6, parts by weight of an addition product of a glycidyl ester of a branched monocarboxylic acid with an unsaturated monocarboxylic and/or dicarboxylic acid. A suit-able branched monocarboxylic acid is represented by a mixture of carboxylic acids having 9 to 11 carbon atoms. ~xamples of suitable unsatura-ted monocarboxylic and dicarboxylic acids are acrylic, methacrylic, crotonic and maleic acid. The use of acrylic and/or methacrylic acid is preferred.
Finally, the mixture of monomers to be employed addition-ally con-tains 0.1 to 5, preferably 1 to 4, parts by weight of an unsaturated amide, for example acrylamide or methacrylamide or a mi~ture of unsaturated amides. These monomers contribute both to the stabilization of the copolymer dispersion and also to the cross-linking of the coating agent manufactured using this dispersion on baking.
The selection of the type and amount of the monomers de pends on the requirements placed on the baked coating in respeet of resistanee to water, weathering, solvents and chemieals. The com-position of the monomer mixture should be laid down within the scope of the previously mentioned ranges of amounts so that a copolymer dispersion is obtained which has a minimum ~ilm-~ormation tempera-ture (MFT) in the range from 0 to 70C, preferably 10 to 60C.
The process aceording to the invention is earried out in the presenee of an emulsifier. This emulsifier is an anionic emulsifier; instead of a single emulsifier, a mixture of various emulsifiers can also be employed. Examples of anionic emulsifiers are the alkali 9 - ~2~
metal salts o~ the hemisulfates of alkylphenols or alco-hols, and also the hemisulfates of oxethylated alkylphenols or oxethylated alcohols~ or also an alkylsulfonate or arylsulfonate, preferably the al~al; metal salts of the hemisulfate of a nonylphenol ~h;ch has been reacted ~ith 4-5 moles of ethylene oxide, and also sodium lauryl sulfate, sodium laurylethoxylate sulfate and secondary sodium al~ane-sulfonates, the carbon chains of ~hich contain 8-Z0 carbon atomsO The amount of the anionic emulsifier is 0.1-5.0% by ~eight, preferably 0.5~3.0X by ~eigh~, relative to the monomers. In addition, in order to ;ncrease the stability of the aqueous copolymer dispersion, it is possible also to employ a non-ionic emulsifier of the type of an ethoxylated alkylphenol or fatty alcohol, for example an addition product from one mole df nonylphenol and 4-30 moles of ethylene oxide m;xed ~ith an anionic emulsifier, also ;n an amount of ~.1 to 5.0, preferably 0.5-3.0X by weiQht~ relative to the monomers.
In addition, a fluorinated surfactant may be used as the emulsifier. The term ~luor;nated surfactant is under-stood to mean surface-act;Ye compounds which contain per-fluoroalkyl radicals having Z to 20 carbon atoms or per-fluoroaralkyl radicals having 8 to 30 rarbon atoms.
Examples of this type of compound are perfluoro 2~ alkylsulfonic acids~ perfluoroaralkylsulfon;c ac;ds, long-chain perfluorocarboxylic acids, perfluoroalkanephosphonic acids, perfLuoroalkanephosphinic acids, the salts of these acids, perfluoroalkyl sulfates and perfluoroaralkyl sulfates.
~a - 1 0 ~ ~z3~3443 Fhe poly~erization process accord,n~ to the ;nven-tion is carr;ed out as an emuls;on polymer;zat,on in an aqueous medium in the kno~n equipment, for example in a ~escel provl~e~ith a s~rrer ~d having ar~ngements for heating ~d cool-ing. The addition of monomers can be carried ou~ in sucha manner that a solution of the total ~ater, the emu'siTier and a part of the initiator ;s initially introduced and the mixture of monomers and the remainder of the initiator are sLo~ly added at the polymerization temperature. However, it 1~ is also possible initially to introduce a part of the water and the emulsifier and to prepare a pre emulsion from the remainder of the water and the emulsifier and from the monomers, ~hich pre-emuls;on is introduced ;nto the polymerization medium. The polymerization is preferably carried out in such a manner that 30-50% by~eight of the water and 10-15% by ~eight of the emulsifier or, if appropriate, mixture of emulsifiers, are ini~ially introduced and a pre-emulsion ;s prepared from the monomers, the rema;ning part of the ~ater and ~he residual emulsifiers~ which pre-emulsion is me~ered into the heated material, which has been in;tially introduced, oYer 1-3 hours.
The process accordin~ to the inven~ion is carried out in the presence of a radical-form;ng init;ator, in particular a peroxide compound or an aiiphatic azo compound.
The ;n;~iator is water-soluble or monomer-soluble. A water soluble in;tiator is preferably used.
Suitible in;t;ators are the customary inorganic 1230 4~3 per-compounds, ;n particular a~moniu~ salts or alkaLi ~etal salts of peroxyd;sulfuric acid and peroxydiphos-phoric acidr for example sodium peroxyd;sulfate, potassium peroxydisulfate, ammonium peroxydisulfate, ammonium peroxy-diphosphate, sodium peroxydiphosphate and potassium peroxy-diphosphate. Ini~iators ~hich are insoluble ;n ~ater but ~hich are soluble in the monomers can also be used, for example, benzoyl ~eroxideO cumol hydroperoxide, di-tert.-butyl peroxide, butyl hydroperox;de and perisopivala~e, 1~ ~hich can also be e~ployed to some extent in combination ~;th reducing agents, such as sodium disulfite~ hydrazine, hydroxylamire and ~ith catalytic amounts of accelerators, such as salts of iron, cobalt, cer;um and vanadyl.
~ater-soluble ;nitiators are preferably used. I~
is also possible to use a comb;nation of ~ater-soluble and or~anic peroxides. In p3rt;cular cases~ ;t is adY;sable to add a buffer sub~tance, for example sodium bicarbonate, to the polymerization batch, in order to maintain the pH
;n the range from 3-5O
In order to regulate the molecular weight, a com-pound is used wh1ch can be used as a chain terminator in the polymer;zation of acrylate monomers.A~t ~rom perhalogenated hydrocarbons, there ca~ be used any co~rpound hav~ng the formula R-SH in ~h jch R denotes an alkyl radical, aryl radical or aralkyl radicalr preferably an alkyl radical having 2-18 carbon atoms9 Examples of regulators of this type are ~thyl mercaptan, n-butyl mercaptan, n-octyl ~ercaptan, lauryl mercaptan and t-dodecyl mercaptan~ The regulator is employed 7n an amount of D.01-590X by weight, pre~erably ~ ~ .
~3~3 - ~2 -of Q.5-3.0X by we;ght, rel~t1ve to ~he total of the mono~
mers. If a particularly h;gh molecular ueight is demanded for certain areas of use, the emulsion polymerizat;on ;s carried out uithout a reyulator~
The polymerization temp~rature is 1n the range from 20 to 100C, preferably 40 to ~0C.
After completion of the add;tion of the mixture of monomers, the total batch îs stirred ~or a further 1-3 hours at 60-90C, preferably at 70-85C~ Subseqwently, the dispersion ;s adjusted to a pH of 7.5-9.5 ~;th a ter-tiary amine, for example triethylamine, diethanolmonomethyl-am;ne, triethanolamine, dimethylisopropylhydroxymethylamine, dimethy(aminoethanol, d;methylaminopropanol or d;ethylam;no-ethanol~ A Rart;cularly good pigment wett;ng of the d;sper-sion, and thus good technological coat;ng prop~rties, ;s o~-ta;ned particularly by the use of d;ethanolmonomethylamine dimethylaminoethanol and dimethylam;nopropano~.
The copolymers obta;ned by the process according to ~e inv~tion have glc~s b~si~on t~atures (TG) in the range from 0 to +60C, preferably from ~10 to +50C. The process accord;ng to the ;nvent;on leads to copolymers ~h;ch have a mean part;cle s;ze tparticle diameter) of O.OS to 0~2 ~m~
preferably from 0.06 to 0.15 ~m.
The aqueous ~opolymer dispersion obta;ned according to the ;nvention has a sol;ds content of 2~ to 60X by we;ght,prcferably 30 to 50X by ue;~h~ and providesr when mixed ~ith an am;noplast res;n which is soluble and/or d;spers;ble in uater, thermosetting coatings wh;ch have excel~ent level;ng and prov;de undercoats~ f;Llers, top coats and s;ngle-layer ~0 coat;ngs of particular elast;city, adhes;on and res;stance to ~2~
corrosion ~nd ~eathrring, in particular resistançe to ~ater AminopLast resins are understood to be the thermo-setting reaction produc~s of aldehydes, preferably form-aldehyde, ~ith polyfunctional amines, for example urea and tr;azines, such as melam;ne ~r benzoguanamine. These res;ns are frequently etheriTied, for example with me~ha-riol, ;n order to promote the solubility ;n water. A mela-mine resin wh;ch is frequently used is hexamethoxymethyl-melamine, ~hich gives clear solutions in ~ater and thus can be metered espec;ally eas;ly and leads to mixtures of b;nders hav;ng good storage staoility~
In add;tionO çonventional alkylated, for example butylated, melamine-formaldehyde res;ns can be used, provided that they satisfy the requirements of uater-solubiLity, of compatibility or of d;spersibil;ty in the finished formu-lation of the coat;ng system The aqueous copolymer dispersion obtained accord-ing to the ;nvention is mixed with the am;noplast res;n in such a manner that trelative to the total resin solids) S-4~% by weight of a~;noplast res;n, preferably 1U-30X by wei~ht, are con~ained ;n the m;xture. --The copolymer d;spers;on can be formulated with anaminoplast res;n to give transparent lac~uers or pi~mented lacquers. The procedure for the manufacture of the lacquers is frequen~ly such tha~ pigments and~or ~;llers, together with customary lacquer auxiliar;es, ;f appropr;ate curing catalysts and~if appropriate~ neutralizers~ are mixed to a p;gment paste ~hich ;s then ~ixed ~ith the binder system. H~lever~ it is frequently also possible ~r the .
'~ .
aminop~ast res;n to serve as ~;x;ng res;n ~pigmen~~~e~-ting agent) in the manufacture of the pigment paste.
All the products customary in the paint and v~rn sh ; industry, can be employed as pigments andtor fiLlers, pro-S viding that they are sufficiently stable under al~al;ne cond;tions, so that the fin;shed coating agent can be stored for several months. The pigmen~ can be added ~o the batch in the manner customary for the manufacture of p;gmented aqueous di~sion paints. In lacquer formu-lat;ons ~ith aqueous copoLymer dispersions, the gloss ;sfrequently improv~d if the pigment is milled ;nto the am;noplast resin and then the aqueous p;gment paste is mixed into the aqueous copolymer dispers;on. An example of a typical p;gment for manufacturing ~hite lacquers is t;tan;um d;oxide.
Apart from the aminoplast resins, various products can be employed as the pigment-~etting agent, and natural or synthet;c polymers, ~h;ch are d;lutable with or solublP
in water and the water-aff;n;ty of ~hich is produced by a relatively large number of hydrophilic molecular constit-uents, are mostly employed. According to ~erman Offen-legun~sschr;ft 2,505~829~ for example, hi~h-boil;ng adduc~s of al;phat;c polyhydr;c alcohols and epoxides, hav;ng a ~olecular ~e;ght of 300-6,000, are emp~oyed.
In the formulat;on of p;g~ented coating compo-sitions, it is frequently necessary also to employ so-called dispersants. In this context, the act;on of the dispersant on the propert;es of ~he f;n;shed f;lm must be taken into account, for example the action on the ~ater-.
resistance. The dispersants empLoyed are, for exa~p~e, the ammon;um salts or alkali metal salts of polymeric c2r-boxylic ac;ds such as polyacryl;c acid or polymethacryl;c ac;d. The amount of dispersant used depends on the type and the amount of the pigments empLoyed and the b;nders.
A particuLar advan~age of the ccpolymer dispersion prepared according to the ;nvent;on is the good compati-bility ~;th a so-called p;gment-~etting resin, ~hich is employed as a particularly effective pig~ent-~etting agent and which preferably has a monomer composition similar to that of the copolymer employed as the binder. This p;g~ent-~etting resir, 7S a copolymer, ~hich is dilutable with water~ based on esters of acrylic or methacrylic acid and hydroph;l;c monomers, ~hich is prepared by known me.hods by radical copolymerization in an organic solvent ~hich can be diluted with water. After the copolymer;zation, the pigment-~etting ~esin is neutralized vith a tertiary am;ne. The p;gment-wetting resin in its form for use is a clear aqueous solution and ;s suitable for the manufac-ture of stable pigment formulations w;th inorganic pigments.The gloss and the leveling nf the baking varnish are fre-quently ~mproved by using a pigment-wetting resin.
Commercially available natural ~r syn~het;c polymers,-~h;ch are d;lutable ~;th or soluble ~n ~ater and the water aff;n;ty of ~hich is produced by a rela~ively ~arge number of hydroph;L;c mo~ecular constituents, can a~so be used as the p;gment~etting agent. Examples for ~his type of produc~
are polyethers, such as polyethy~ene oxides and polypropyl-ene ox;des~
.
~23~
The finished formulat;ons of the coating agent can also have a tertiary amine addéd to increase the storage stability. 7he preferred pH range is 7-9.
In order to decrease the baking temperature, the coating agents can also be m;xed ~ith a curing catalyst.
A catalyst ~hich is frequently used is paratoluenesulfon-,c ac;d.
The coa.ing agent based on the copolymer dispersion obta;ned according to the 1nvent;on can be appl;ed ~o a large number of substrates, ~hich must, of course, bc stable at the baking temperature. For this reason, metallic substrates are part;cularly suitable~ for example objects made of iron, steel, alum;num, copper~ bronze and brass.
Ceram;c surfaces, glass and ~ood can also be coated.
Emuls;on lacquers can, for example, be appl;ed to the sub-strates using spray guns, or by brush~ squeeQee, roller or by d;pp;ng~ In practice, the coated object is predomi-nantly aired and dried in a;r at room temperature or at a temperature ~h;ch is only slightly elevated~ Then the 2a coat;ng ;s cured by "baking'7 at a temperatwre from 80-180~C.
The coatings are baked, as a rule~ for a period of 10-30 m;nutes~ The layer thicknesses of the ba~ed coatings are in the range ~rom 15 to 80 ~m, prefera~ly 2S to bO ~m.
Baked transparent lacquer films and p;gmented lacquer films based on the copolymer dispersion prepared according eo the invention are distinguished by unexpect-ed~y high resistance to ~ater In add;tion, these lacquer fiLms exh;bit good covering, smoo~hness, elas~;c;ty, gloss~
adhesion and resistance to ~eather;ng and yello~ing. A
.
~$
~230~l~3 good chemical resistanee is exhibi.ed pa ~icular'y to-~ards water, solvents and alkaline and acid agents. Tl!e copolymer dis~ersion is very well suited fo the manufac-ture of double-layer metallic lacquers~ This type o~
lacquers formulated with the aid of this dispersion exhibited exceptional resistance in the known "Flor;da test", thus, for example, metall;c silver lacquers only lost about 10X
of gloss ~ithin 12 months.
The following examples serve ~o illustrate ~he ;nvention in more detail. Percentages and ratios relate, in each case~ to the weight, and the amounts of solutions and dispers;ons relate, in each case, to the solid materia'.
The polymer;zat~;on experiments ~ere carr;ed ou~ n a mllltineck fLask having a stirrer, thermometer, dropping funnel and a thermosta-ted bath.
If a mercaptan ~as used as the regulator, care ~as taken that the ~ercaptan ~as added to the ~i~ture of monomers or the pre-emulsion only shortly before the start o~ the meter;ng-in, s;nce if the mixture of monomers or pre-emulsion, contain~ng ~he mercaptan, ;s allowed to stand for some time, a yellow or brown coloration occurred.
Example 1 A monomer emuls;on ~as prepared fro ~00 ~ of styrcne 200 g of ethyl acrylate 200 g of vinyl ester of a branched saturated C10-' ~onocarboxylic acid having a carboxyl groupon a tert. carbon atom .,~ .
~z~
~ 18 -80 9 of hydroxypropyl methacrylate S0 9 of methacrylic acid 20 9 of addition product of a glyc;dyl ester o~
a branched C1o carboxylic ac;d and crotonic a~id (1:1) 10 g of metharrylamide 8 g of sodium laurylethoxylate sulfate (w;th 2 -6 ~oles of ethylene oxide~
10 g of Lauryl mercaptan
These agents ~ssist the flowing together of the coat;ng during dry;ng in a;r before bak;ng. The follow;ng are used: long-chain alcohols, d;methylformam;de, tributyi phosphate~ polyethylene or polypropylene glycols~ 2-butoxy-ethanol acetateO diacetone alcohol, 3,5,5-trimethyl-2-cyclohexen-1-one~ caprolac~am, addition products of poly-hydr;c alcohols ~ith C2 to C4 epox;des or d;ssolved and compatible cooolymer resins.
The d;sadvantage of the add;t;ves ~entioned is uC r ~rl that there are adverse effects, not only on the gloss and level-ing, but also on other technological properties of the films due to the hydrophilic and low molecular weight additives. In part-icular, -the resistance to water and chemicals oE -the baked coatings suffer adverse effects.
~ ccording to the German OfEenlegungsschrift 2,709,308, specifically for improving the water-resistance of coatings which have been prepared using dispersions of thermosetting copolymers, in the preparation of the dispersions, alkali metal or alkaline earth metal ions, for example from initiators and emulsifiers, should be replaced by ammonium ions. ~Iowever, even with dispers-ions of this type, water-resistances of only about 120 hours are achieved.
The object of the invention is to make an aqueous dispersion of a copolymer which can be crosslinked with an amino-plast resin by the action of heat and which leads to coatings which have good levelling and are free of flaws, and which, in particular, are water-resistant, on metallic substrates.
It has been found that aqueous copolymer dispersions can be prepared, with a particular choice of the monomers and the ratios of their amounts, from styrene, esters of acrylic or methacrylic acid, vinyl esters, monomers containing hydroxyl groups, acrylic and/or methacrylic acid, acrylamide and/or metha~
crylamide and addition compounds of glycidyl esters of branched monocarboxylic acids with unsaturated carboxylic acids, by polymerization in the presence of an anionic emulsifier and a ~ - 'L -~236~4~3 radical initiator and, if appropriate, a non-ionic emulsifier, which dispersions, in combination with aminoplas-t resins, provide thermosetting coatings with excellent properties. These coatings provide highly elastic, wea-ther-resistant, water-resistant surface coatings, which have high adhesion and are free of flaws, on metallic substrates.
Thus, the invention relates to a process for the prepara-tion of an aqueous dispersion of a copolymer which can be cross-linked with an aminoplast resin by the action of heat and which is prepared by copolymerization of monomers from the group comprising styrene, esters of acrylic acid, esters of methacrylic acid, vinyl esters, monoolefinic unsaturated monomers having hydroxyl groups, acrylic acid, methacrylic acid, unsaturated amides and other functional comonomers, in an aqueous phase in the presence of a radical-forming initiator and an anionic emulsifier, which com prises copolymerizing a mixture of 30 to 60 parts by weight of styrene and/or methyl meth-acrylate, 20 to 50 parts by weight of an ester of acrylic acid or of methacrylic acid, the homopolymer of which has a glass tempera-ture TG below +50C, or a mixture of these esters, 5 to 30 parts by weight of a vinyl ester of a branched saturated monocarboxylic acid, which has side chains having 8 to 12 carbon atoms and in which the carboxyl group is on a tertiary carbon atom, 5 to 15 parts by weight of a hydroxyalkyl ester of a mono-., , ~3~3 olefinic unsaturated monocarboxylic acid, 0.5 to 15 parts by weight of an ~ unsaturated mono-carboxylic acid and/or unsaturated dicarboxylic acid, 0.1 to 8 parts by weight of an addition product of a glycidyl ester of a branched monocarboxylic acid with an unsaturat-ed monocarboxylic or dicarboxylic acid, and 0.1 to 5 parts by weight of an unsaturated amide.
The invention also relates to the use of the copolymer dispersion, prepared in this manner, for -the manufacturing of coat-ings which can be crosslinked by the action of heat.
30 to 60, preferably 35 to 55, parts by weight of styrene and/or methyl methacrylate are employed as the monomers which serve as the "hardening" component. Methyl methacrylate is preferably employed.
The mixture of monomers to be employed contains as the "plasticizing" component 20 to 50, preferably 25 to 45, parts by weight of an ester of acrylic acid or of methacrylic acid, the homopolymer of which has a glass temperature TG below +50C, or mixtures o~ these esters. Examples of these monomers are ethyl, acrylate, propyl acrylate, isopropyl acrylate, and n- and i-butyl, 2-ethylhexyl and decyl acrylates and methacrylates.
Furthermore, the mixture of monomers to be employed con-tains 5 to 30, preferably 8 to 26, parts by weight of a vinyl ester of a bxanched saturated monocarboxylic acid which has side chains having 8 to 12 carbon atoms and the carboxyl group on a tertiary ~2~ 3 carbon atom. This type of carboxylic acid can be obtained by Koch's method of synthesis from olefins, carbon monoxide and water.
The vinyl ester of a branched satura-ted monocarboxylic acid having a total oE 10 carbon a-toms, the carboxyl group of which is on a tertiary carbon atom, is preferably used.
In order to achieve an adequate reactivity of the coat-ing mixture to be manufactured from the dispersion, an additional monomer employed, in an amount of 5 to 15, preferably 6 to 12, parts by weight, is a hydroxyalkyl ester of a monoolefinic un-saturated monocarboxylic acid, for example hydroxyethyl acrylate, 2-hydroxypropyl acrylate, hydroxyethyl me-thacrylate, 2-hydroxy-propyl methacrylate, 4-hydroxybutyl methacrylate, glycerol mono-methacrylate, trimethylolpropane monoacrylate, reaction products cf hydroxyethyl methacrylate with 2-8 moles of ethylene oxide, neopentylglycol monomethacrylate and triethylene glycol monoacry-late.
The incorporation of unsaturated monocarboxylic acids in-to the copolymer increases the stability of the dispersion during manufacture, storage and use. ~igh shear forces occur particularly for industrial lacquers during the manufacture and application of the coating agents. For this reason, the mixture of monomers to be employed contains 0.5 to 10, preferably 1 to 8, parts by weight of an a,~-unsaturated monocarboxylic acid and/or an unsaturated di-carboxylic acid~ Suitable acids are acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid and itaconic acid.
~crylic acid and/or methacrylic acid are preferably used.
In addition, the mixture of monomers to be employed con-, ~
~2~
tains 0.1 to 8, preferably 1 to 6, parts by weight of an addition product of a glycidyl ester of a branched monocarboxylic acid with an unsaturated monocarboxylic and/or dicarboxylic acid. A suit-able branched monocarboxylic acid is represented by a mixture of carboxylic acids having 9 to 11 carbon atoms. ~xamples of suitable unsatura-ted monocarboxylic and dicarboxylic acids are acrylic, methacrylic, crotonic and maleic acid. The use of acrylic and/or methacrylic acid is preferred.
Finally, the mixture of monomers to be employed addition-ally con-tains 0.1 to 5, preferably 1 to 4, parts by weight of an unsaturated amide, for example acrylamide or methacrylamide or a mi~ture of unsaturated amides. These monomers contribute both to the stabilization of the copolymer dispersion and also to the cross-linking of the coating agent manufactured using this dispersion on baking.
The selection of the type and amount of the monomers de pends on the requirements placed on the baked coating in respeet of resistanee to water, weathering, solvents and chemieals. The com-position of the monomer mixture should be laid down within the scope of the previously mentioned ranges of amounts so that a copolymer dispersion is obtained which has a minimum ~ilm-~ormation tempera-ture (MFT) in the range from 0 to 70C, preferably 10 to 60C.
The process aceording to the invention is earried out in the presenee of an emulsifier. This emulsifier is an anionic emulsifier; instead of a single emulsifier, a mixture of various emulsifiers can also be employed. Examples of anionic emulsifiers are the alkali 9 - ~2~
metal salts o~ the hemisulfates of alkylphenols or alco-hols, and also the hemisulfates of oxethylated alkylphenols or oxethylated alcohols~ or also an alkylsulfonate or arylsulfonate, preferably the al~al; metal salts of the hemisulfate of a nonylphenol ~h;ch has been reacted ~ith 4-5 moles of ethylene oxide, and also sodium lauryl sulfate, sodium laurylethoxylate sulfate and secondary sodium al~ane-sulfonates, the carbon chains of ~hich contain 8-Z0 carbon atomsO The amount of the anionic emulsifier is 0.1-5.0% by ~eight, preferably 0.5~3.0X by ~eigh~, relative to the monomers. In addition, in order to ;ncrease the stability of the aqueous copolymer dispersion, it is possible also to employ a non-ionic emulsifier of the type of an ethoxylated alkylphenol or fatty alcohol, for example an addition product from one mole df nonylphenol and 4-30 moles of ethylene oxide m;xed ~ith an anionic emulsifier, also ;n an amount of ~.1 to 5.0, preferably 0.5-3.0X by weiQht~ relative to the monomers.
In addition, a fluorinated surfactant may be used as the emulsifier. The term ~luor;nated surfactant is under-stood to mean surface-act;Ye compounds which contain per-fluoroalkyl radicals having Z to 20 carbon atoms or per-fluoroaralkyl radicals having 8 to 30 rarbon atoms.
Examples of this type of compound are perfluoro 2~ alkylsulfonic acids~ perfluoroaralkylsulfon;c ac;ds, long-chain perfluorocarboxylic acids, perfluoroalkanephosphonic acids, perfLuoroalkanephosphinic acids, the salts of these acids, perfluoroalkyl sulfates and perfluoroaralkyl sulfates.
~a - 1 0 ~ ~z3~3443 Fhe poly~erization process accord,n~ to the ;nven-tion is carr;ed out as an emuls;on polymer;zat,on in an aqueous medium in the kno~n equipment, for example in a ~escel provl~e~ith a s~rrer ~d having ar~ngements for heating ~d cool-ing. The addition of monomers can be carried ou~ in sucha manner that a solution of the total ~ater, the emu'siTier and a part of the initiator ;s initially introduced and the mixture of monomers and the remainder of the initiator are sLo~ly added at the polymerization temperature. However, it 1~ is also possible initially to introduce a part of the water and the emulsifier and to prepare a pre emulsion from the remainder of the water and the emulsifier and from the monomers, ~hich pre-emuls;on is introduced ;nto the polymerization medium. The polymerization is preferably carried out in such a manner that 30-50% by~eight of the water and 10-15% by ~eight of the emulsifier or, if appropriate, mixture of emulsifiers, are ini~ially introduced and a pre-emulsion ;s prepared from the monomers, the rema;ning part of the ~ater and ~he residual emulsifiers~ which pre-emulsion is me~ered into the heated material, which has been in;tially introduced, oYer 1-3 hours.
The process accordin~ to the inven~ion is carried out in the presence of a radical-form;ng init;ator, in particular a peroxide compound or an aiiphatic azo compound.
The ;n;~iator is water-soluble or monomer-soluble. A water soluble in;tiator is preferably used.
Suitible in;t;ators are the customary inorganic 1230 4~3 per-compounds, ;n particular a~moniu~ salts or alkaLi ~etal salts of peroxyd;sulfuric acid and peroxydiphos-phoric acidr for example sodium peroxyd;sulfate, potassium peroxydisulfate, ammonium peroxydisulfate, ammonium peroxy-diphosphate, sodium peroxydiphosphate and potassium peroxy-diphosphate. Ini~iators ~hich are insoluble ;n ~ater but ~hich are soluble in the monomers can also be used, for example, benzoyl ~eroxideO cumol hydroperoxide, di-tert.-butyl peroxide, butyl hydroperox;de and perisopivala~e, 1~ ~hich can also be e~ployed to some extent in combination ~;th reducing agents, such as sodium disulfite~ hydrazine, hydroxylamire and ~ith catalytic amounts of accelerators, such as salts of iron, cobalt, cer;um and vanadyl.
~ater-soluble ;nitiators are preferably used. I~
is also possible to use a comb;nation of ~ater-soluble and or~anic peroxides. In p3rt;cular cases~ ;t is adY;sable to add a buffer sub~tance, for example sodium bicarbonate, to the polymerization batch, in order to maintain the pH
;n the range from 3-5O
In order to regulate the molecular weight, a com-pound is used wh1ch can be used as a chain terminator in the polymer;zation of acrylate monomers.A~t ~rom perhalogenated hydrocarbons, there ca~ be used any co~rpound hav~ng the formula R-SH in ~h jch R denotes an alkyl radical, aryl radical or aralkyl radicalr preferably an alkyl radical having 2-18 carbon atoms9 Examples of regulators of this type are ~thyl mercaptan, n-butyl mercaptan, n-octyl ~ercaptan, lauryl mercaptan and t-dodecyl mercaptan~ The regulator is employed 7n an amount of D.01-590X by weight, pre~erably ~ ~ .
~3~3 - ~2 -of Q.5-3.0X by we;ght, rel~t1ve to ~he total of the mono~
mers. If a particularly h;gh molecular ueight is demanded for certain areas of use, the emulsion polymerizat;on ;s carried out uithout a reyulator~
The polymerization temp~rature is 1n the range from 20 to 100C, preferably 40 to ~0C.
After completion of the add;tion of the mixture of monomers, the total batch îs stirred ~or a further 1-3 hours at 60-90C, preferably at 70-85C~ Subseqwently, the dispersion ;s adjusted to a pH of 7.5-9.5 ~;th a ter-tiary amine, for example triethylamine, diethanolmonomethyl-am;ne, triethanolamine, dimethylisopropylhydroxymethylamine, dimethy(aminoethanol, d;methylaminopropanol or d;ethylam;no-ethanol~ A Rart;cularly good pigment wett;ng of the d;sper-sion, and thus good technological coat;ng prop~rties, ;s o~-ta;ned particularly by the use of d;ethanolmonomethylamine dimethylaminoethanol and dimethylam;nopropano~.
The copolymers obta;ned by the process according to ~e inv~tion have glc~s b~si~on t~atures (TG) in the range from 0 to +60C, preferably from ~10 to +50C. The process accord;ng to the ;nvent;on leads to copolymers ~h;ch have a mean part;cle s;ze tparticle diameter) of O.OS to 0~2 ~m~
preferably from 0.06 to 0.15 ~m.
The aqueous ~opolymer dispersion obta;ned according to the ;nvention has a sol;ds content of 2~ to 60X by we;ght,prcferably 30 to 50X by ue;~h~ and providesr when mixed ~ith an am;noplast res;n which is soluble and/or d;spers;ble in uater, thermosetting coatings wh;ch have excel~ent level;ng and prov;de undercoats~ f;Llers, top coats and s;ngle-layer ~0 coat;ngs of particular elast;city, adhes;on and res;stance to ~2~
corrosion ~nd ~eathrring, in particular resistançe to ~ater AminopLast resins are understood to be the thermo-setting reaction produc~s of aldehydes, preferably form-aldehyde, ~ith polyfunctional amines, for example urea and tr;azines, such as melam;ne ~r benzoguanamine. These res;ns are frequently etheriTied, for example with me~ha-riol, ;n order to promote the solubility ;n water. A mela-mine resin wh;ch is frequently used is hexamethoxymethyl-melamine, ~hich gives clear solutions in ~ater and thus can be metered espec;ally eas;ly and leads to mixtures of b;nders hav;ng good storage staoility~
In add;tionO çonventional alkylated, for example butylated, melamine-formaldehyde res;ns can be used, provided that they satisfy the requirements of uater-solubiLity, of compatibility or of d;spersibil;ty in the finished formu-lation of the coat;ng system The aqueous copolymer dispersion obtained accord-ing to the ;nvention is mixed with the am;noplast res;n in such a manner that trelative to the total resin solids) S-4~% by weight of a~;noplast res;n, preferably 1U-30X by wei~ht, are con~ained ;n the m;xture. --The copolymer d;spers;on can be formulated with anaminoplast res;n to give transparent lac~uers or pi~mented lacquers. The procedure for the manufacture of the lacquers is frequen~ly such tha~ pigments and~or ~;llers, together with customary lacquer auxiliar;es, ;f appropr;ate curing catalysts and~if appropriate~ neutralizers~ are mixed to a p;gment paste ~hich ;s then ~ixed ~ith the binder system. H~lever~ it is frequently also possible ~r the .
'~ .
aminop~ast res;n to serve as ~;x;ng res;n ~pigmen~~~e~-ting agent) in the manufacture of the pigment paste.
All the products customary in the paint and v~rn sh ; industry, can be employed as pigments andtor fiLlers, pro-S viding that they are sufficiently stable under al~al;ne cond;tions, so that the fin;shed coating agent can be stored for several months. The pigmen~ can be added ~o the batch in the manner customary for the manufacture of p;gmented aqueous di~sion paints. In lacquer formu-lat;ons ~ith aqueous copoLymer dispersions, the gloss ;sfrequently improv~d if the pigment is milled ;nto the am;noplast resin and then the aqueous p;gment paste is mixed into the aqueous copolymer dispers;on. An example of a typical p;gment for manufacturing ~hite lacquers is t;tan;um d;oxide.
Apart from the aminoplast resins, various products can be employed as the pigment-~etting agent, and natural or synthet;c polymers, ~h;ch are d;lutable with or solublP
in water and the water-aff;n;ty of ~hich is produced by a relatively large number of hydrophilic molecular constit-uents, are mostly employed. According to ~erman Offen-legun~sschr;ft 2,505~829~ for example, hi~h-boil;ng adduc~s of al;phat;c polyhydr;c alcohols and epoxides, hav;ng a ~olecular ~e;ght of 300-6,000, are emp~oyed.
In the formulat;on of p;g~ented coating compo-sitions, it is frequently necessary also to employ so-called dispersants. In this context, the act;on of the dispersant on the propert;es of ~he f;n;shed f;lm must be taken into account, for example the action on the ~ater-.
resistance. The dispersants empLoyed are, for exa~p~e, the ammon;um salts or alkali metal salts of polymeric c2r-boxylic ac;ds such as polyacryl;c acid or polymethacryl;c ac;d. The amount of dispersant used depends on the type and the amount of the pigments empLoyed and the b;nders.
A particuLar advan~age of the ccpolymer dispersion prepared according to the ;nvent;on is the good compati-bility ~;th a so-called p;gment-~etting resin, ~hich is employed as a particularly effective pig~ent-~etting agent and which preferably has a monomer composition similar to that of the copolymer employed as the binder. This p;g~ent-~etting resir, 7S a copolymer, ~hich is dilutable with water~ based on esters of acrylic or methacrylic acid and hydroph;l;c monomers, ~hich is prepared by known me.hods by radical copolymerization in an organic solvent ~hich can be diluted with water. After the copolymer;zation, the pigment-~etting ~esin is neutralized vith a tertiary am;ne. The p;gment-wetting resin in its form for use is a clear aqueous solution and ;s suitable for the manufac-ture of stable pigment formulations w;th inorganic pigments.The gloss and the leveling nf the baking varnish are fre-quently ~mproved by using a pigment-wetting resin.
Commercially available natural ~r syn~het;c polymers,-~h;ch are d;lutable ~;th or soluble ~n ~ater and the water aff;n;ty of ~hich is produced by a rela~ively ~arge number of hydroph;L;c mo~ecular constituents, can a~so be used as the p;gment~etting agent. Examples for ~his type of produc~
are polyethers, such as polyethy~ene oxides and polypropyl-ene ox;des~
.
~23~
The finished formulat;ons of the coating agent can also have a tertiary amine addéd to increase the storage stability. 7he preferred pH range is 7-9.
In order to decrease the baking temperature, the coating agents can also be m;xed ~ith a curing catalyst.
A catalyst ~hich is frequently used is paratoluenesulfon-,c ac;d.
The coa.ing agent based on the copolymer dispersion obta;ned according to the 1nvent;on can be appl;ed ~o a large number of substrates, ~hich must, of course, bc stable at the baking temperature. For this reason, metallic substrates are part;cularly suitable~ for example objects made of iron, steel, alum;num, copper~ bronze and brass.
Ceram;c surfaces, glass and ~ood can also be coated.
Emuls;on lacquers can, for example, be appl;ed to the sub-strates using spray guns, or by brush~ squeeQee, roller or by d;pp;ng~ In practice, the coated object is predomi-nantly aired and dried in a;r at room temperature or at a temperature ~h;ch is only slightly elevated~ Then the 2a coat;ng ;s cured by "baking'7 at a temperatwre from 80-180~C.
The coatings are baked, as a rule~ for a period of 10-30 m;nutes~ The layer thicknesses of the ba~ed coatings are in the range ~rom 15 to 80 ~m, prefera~ly 2S to bO ~m.
Baked transparent lacquer films and p;gmented lacquer films based on the copolymer dispersion prepared according eo the invention are distinguished by unexpect-ed~y high resistance to ~ater In add;tion, these lacquer fiLms exh;bit good covering, smoo~hness, elas~;c;ty, gloss~
adhesion and resistance to ~eather;ng and yello~ing. A
.
~$
~230~l~3 good chemical resistanee is exhibi.ed pa ~icular'y to-~ards water, solvents and alkaline and acid agents. Tl!e copolymer dis~ersion is very well suited fo the manufac-ture of double-layer metallic lacquers~ This type o~
lacquers formulated with the aid of this dispersion exhibited exceptional resistance in the known "Flor;da test", thus, for example, metall;c silver lacquers only lost about 10X
of gloss ~ithin 12 months.
The following examples serve ~o illustrate ~he ;nvention in more detail. Percentages and ratios relate, in each case~ to the weight, and the amounts of solutions and dispers;ons relate, in each case, to the solid materia'.
The polymer;zat~;on experiments ~ere carr;ed ou~ n a mllltineck fLask having a stirrer, thermometer, dropping funnel and a thermosta-ted bath.
If a mercaptan ~as used as the regulator, care ~as taken that the ~ercaptan ~as added to the ~i~ture of monomers or the pre-emulsion only shortly before the start o~ the meter;ng-in, s;nce if the mixture of monomers or pre-emulsion, contain~ng ~he mercaptan, ;s allowed to stand for some time, a yellow or brown coloration occurred.
Example 1 A monomer emuls;on ~as prepared fro ~00 ~ of styrcne 200 g of ethyl acrylate 200 g of vinyl ester of a branched saturated C10-' ~onocarboxylic acid having a carboxyl groupon a tert. carbon atom .,~ .
~z~
~ 18 -80 9 of hydroxypropyl methacrylate S0 9 of methacrylic acid 20 9 of addition product of a glyc;dyl ester o~
a branched C1o carboxylic ac;d and crotonic a~id (1:1) 10 g of metharrylamide 8 g of sodium laurylethoxylate sulfate (w;th 2 -6 ~oles of ethylene oxide~
10 g of Lauryl mercaptan
4 9 of ammonium perfluorooctyl sulfate and 900 y of ~ater~
The emulsion ~as metered into a solut;on of 8 9 of sodiu~
laury~ethoxylate sulfate ~w;th 2-6 moles of ethylene oxide) in 60Q g of ~ater over 2 hours at 80C. A solution of 2 9 of ammonium perox~disulfate in 40 9 of ~ater was added to the batch in parallel to the ~onomer emulsion. After com-pletion of the introduction of the monomers, the mixture was stirred a further 3 hours at 80C. After rooling down to room temperature, the copolymer dispersion was adjusted to a p~ of 8.0 ~ith an aqueous solut;on of dim~thylamino-ethanol~ The copolymer dispers;on had a soLids content o~
35%. Its ~inimum f;lm-fornlation temperature was +16C and the gliss temperature of the copolrmer determ;ned by differ-ential thermal analysis tDTA) was +5~C.
~
A monomer emuls;on ~as prepared from 170 9 of styrene ~70 g of methyl methacrylate 170 9 of ethy~ acrylate 3~
17Q g o~ v;nyl ester of a branched saturated C10-monocarboxylic acid hav;ng a carboxyl group on a tert. carbon atom 70 9 of hydroxypropyl methacrylate 60 9 of methacrylic acid 15 9 of addition product of a glycidyl ester of a branched saturated C10-carboxyl;c acid and acrylic acid ~
10 9 of methacrylamide 12 9 of sodium laurylethoxylate sulfate (with 2-6 moles of ethylene ox;de) 3 9 of sod;um perfluorooctyl sulfonat~
10 9 of lauryl mercaptan and 700 9 of ~ater and th;s was metered into a solut;on of 8 g of sodium lauryl-ethoxy~ate sulfate ;n 500 9 of water over 2 hours at 80C.
The subse~uent proced,ure ~as analogous to that in Example 1. A d;spersion was obtained hav;ng a sol;ds content of 38% and a glass temperature TG f the copolymer of 151C.
Example 3 . . _ A ~onomer emulsion was prepared from 200 9 of styrene 140 9 of methyl methacrylate 160 9 of ethyl acrylate 180 g of v;nyL eseer of a branched saturated C10-monocarboxy~ic ac;d hav;ng a carboxyl group on ~ tert. carbon atom 70 g~of hydroxypropyl methacrylate 60 9 o~ methacryl;c ac;d ~23~3
The emulsion ~as metered into a solut;on of 8 9 of sodiu~
laury~ethoxylate sulfate ~w;th 2-6 moles of ethylene oxide) in 60Q g of ~ater over 2 hours at 80C. A solution of 2 9 of ammonium perox~disulfate in 40 9 of ~ater was added to the batch in parallel to the ~onomer emulsion. After com-pletion of the introduction of the monomers, the mixture was stirred a further 3 hours at 80C. After rooling down to room temperature, the copolymer dispersion was adjusted to a p~ of 8.0 ~ith an aqueous solut;on of dim~thylamino-ethanol~ The copolymer dispers;on had a soLids content o~
35%. Its ~inimum f;lm-fornlation temperature was +16C and the gliss temperature of the copolrmer determ;ned by differ-ential thermal analysis tDTA) was +5~C.
~
A monomer emuls;on ~as prepared from 170 9 of styrene ~70 g of methyl methacrylate 170 9 of ethy~ acrylate 3~
17Q g o~ v;nyl ester of a branched saturated C10-monocarboxylic acid hav;ng a carboxyl group on a tert. carbon atom 70 9 of hydroxypropyl methacrylate 60 9 of methacrylic acid 15 9 of addition product of a glycidyl ester of a branched saturated C10-carboxyl;c acid and acrylic acid ~
10 9 of methacrylamide 12 9 of sodium laurylethoxylate sulfate (with 2-6 moles of ethylene ox;de) 3 9 of sod;um perfluorooctyl sulfonat~
10 9 of lauryl mercaptan and 700 9 of ~ater and th;s was metered into a solut;on of 8 g of sodium lauryl-ethoxy~ate sulfate ;n 500 9 of water over 2 hours at 80C.
The subse~uent proced,ure ~as analogous to that in Example 1. A d;spersion was obtained hav;ng a sol;ds content of 38% and a glass temperature TG f the copolymer of 151C.
Example 3 . . _ A ~onomer emulsion was prepared from 200 9 of styrene 140 9 of methyl methacrylate 160 9 of ethyl acrylate 180 g of v;nyL eseer of a branched saturated C10-monocarboxy~ic ac;d hav;ng a carboxyl group on ~ tert. carbon atom 70 g~of hydroxypropyl methacrylate 60 9 o~ methacryl;c ac;d ~23~3
5 9 of addition product Gf glyc~dyi ester of 3 branched saturated C10-carboxylic acid and acryl;c ac;d (1:1) -10 g of sodium lauryl sulfate 10 9 of lauryl mercaptan and 700 9 of water.
This monomer emulsion ~as metered ;nto a solut;on of 8 9 of sodiu~ lauryl sulfate in 550 9 of water according to the deta;ls of Example 1 and, during this, the polymer-;zat;on was carr;ed out ~ith ammonium peroxydisulfate as the init;ator.
The solids content of the dispersion ~as 38Z and the glass temperature TG of the copolymer ~as ~47C.
Example_4 .!
A monomer emuls;on ~as prepared from 200 g of styrene 200 9 of methyl methacrylate 200 9 of ethyl acrylate 180 g of vinyl ester of a branched saturated C
monocarboxyl~c acid having a car~oxyl group on a tert. carbon atom 90 g o~ hydroxypropyl methacrylate 70 9 of methacrylic ac;d 15 g of add;tion product of a glycidyl ester of a branched saturated C10-carboxylic ac;d an~
acrylic ac;d ~
~0 9 of sodium laurylethoxylate sulfate tw~th 2-
This monomer emulsion ~as metered ;nto a solut;on of 8 9 of sodiu~ lauryl sulfate in 550 9 of water according to the deta;ls of Example 1 and, during this, the polymer-;zat;on was carr;ed out ~ith ammonium peroxydisulfate as the init;ator.
The solids content of the dispersion ~as 38Z and the glass temperature TG of the copolymer ~as ~47C.
Example_4 .!
A monomer emuls;on ~as prepared from 200 g of styrene 200 9 of methyl methacrylate 200 9 of ethyl acrylate 180 g of vinyl ester of a branched saturated C
monocarboxyl~c acid having a car~oxyl group on a tert. carbon atom 90 g o~ hydroxypropyl methacrylate 70 9 of methacrylic ac;d 15 g of add;tion product of a glycidyl ester of a branched saturated C10-carboxylic ac;d an~
acrylic ac;d ~
~0 9 of sodium laurylethoxylate sulfate tw~th 2-
6 moles of ethylene ox;de) 4 ~ of sod;um perfluorooctyl phosphonate .
;s~ , , .
~31~
12 9 of lauryl mercaP'can and 680 9 of ~ater, uhich, accord;ng eo the procedure of Example 1, in a sol~ -ution of 8 9 of sodium laurylethoxylate sulfate (~ith Z-6 moles of ethylene oxide) and 550 9 of ~ater was brought to polymerizat;on ;n the presence of ammonium peroxydisulfate.
The copolymer dispersion had a solids conte~t of 40% and a ~inimum f;lm-formation temperature tMFT) of +26C~ The glass temperature T6 of the copolymer was ~53C~
Use ExampLe 1 Preparation of a white lacquer paint based on the copolyme~ d;spersion according to Example 1:
A. Pigment paste 40 9 of hexamethoxymethylmelamine tSOX in water) 3.0 g of sodium polyacrylate t25% ;n ~ater) 1.~ 9 of addition product of 1 mo'e of nonyl-pheno'i and 6-10 ~oles of ethylene oxide 0~6 ~ of commercial defoamer 10~0 9 of sodium n;tr;te (SX in ~ater~ and 160 g of titanium dioxide (rut;le type~
B. B;nder 540 g of copolymer d;spersion ~35% strength) Part A was dispersed for 12 hours in a ball mill~
t,hen part B was mixed in and the batch was again ground for 10 hours ;n the ball millO The ~h;te lacquer, having a flo~ v-scometer t;me (according to DIN 53,211) of 20 seconds~ wa~ sprayed onto degreased steel plates and, after an a;ring time of 10 minutes, baked at 16~C for 30 minutes.
The layer th;ckness was 35 ~m, the gloss value 1~3~
(accord;ng to DIN 6?,530) ~as 88% and the ~ater-res;stance value ~accord;ng to the absorbent cotton-~ad test ~ethod) ~as 1,100 hours.
Example 5 A pigment~wetting agent ~as prepared from 92 9 of methyl methacrylate
;s~ , , .
~31~
12 9 of lauryl mercaP'can and 680 9 of ~ater, uhich, accord;ng eo the procedure of Example 1, in a sol~ -ution of 8 9 of sodium laurylethoxylate sulfate (~ith Z-6 moles of ethylene oxide) and 550 9 of ~ater was brought to polymerizat;on ;n the presence of ammonium peroxydisulfate.
The copolymer dispersion had a solids conte~t of 40% and a ~inimum f;lm-formation temperature tMFT) of +26C~ The glass temperature T6 of the copolymer was ~53C~
Use ExampLe 1 Preparation of a white lacquer paint based on the copolyme~ d;spersion according to Example 1:
A. Pigment paste 40 9 of hexamethoxymethylmelamine tSOX in water) 3.0 g of sodium polyacrylate t25% ;n ~ater) 1.~ 9 of addition product of 1 mo'e of nonyl-pheno'i and 6-10 ~oles of ethylene oxide 0~6 ~ of commercial defoamer 10~0 9 of sodium n;tr;te (SX in ~ater~ and 160 g of titanium dioxide (rut;le type~
B. B;nder 540 g of copolymer d;spersion ~35% strength) Part A was dispersed for 12 hours in a ball mill~
t,hen part B was mixed in and the batch was again ground for 10 hours ;n the ball millO The ~h;te lacquer, having a flo~ v-scometer t;me (according to DIN 53,211) of 20 seconds~ wa~ sprayed onto degreased steel plates and, after an a;ring time of 10 minutes, baked at 16~C for 30 minutes.
The layer th;ckness was 35 ~m, the gloss value 1~3~
(accord;ng to DIN 6?,530) ~as 88% and the ~ater-res;stance value ~accord;ng to the absorbent cotton-~ad test ~ethod) ~as 1,100 hours.
Example 5 A pigment~wetting agent ~as prepared from 92 9 of methyl methacrylate
7~ g of ethyL acrylate 25 9 of hydroxypropyl methacrylate 13 9 of acrylic acid S g of di-tertO~butyl peroxide 180 9 of b~tyldiglycol and ~ 8 of lauryl mercaptan by heat;ng at 120C for 6 hours, the sol;ds content of wh;ch was 51.5%. The acid number (according to DI~ 53,402) ~as 47 and the hydroxyl number (according to DIN 53,783) ~as 50. The res;n soLution ~as d;luted to a solids con-tent of ~5X with an,aqueous solution of dimethylaminoethanol.
The clear aqueous res;n solution was employed in th;s form as a p;gment-~etting agent.
Use Example 2 ~ . .
Preparat;on of white lacquer pa;nts based on the copolymer d;spersions according to Examples 1, Z, 3 and It and the pigment wetting agent according to Example 5:
A. Pigment paste 20.60 g of t;tanium d;ox;de (rutile type~
6.25 g of hexamethoxymethylmelamine 7.80 9 of pigment-wett;ng agent tExamp~e 5) and 0.2Q g of commer5ial uetting agent 7~ .
~3~3 .
B. Binder 55.45 9 of copo~ymer dispers;on according to Examples 1, 2, 3 and 4 ~.55 9 of pigment-wett;ng agent tExample 53 and S 0.15 8 of commercial corros;on ;nh;bitor.
Uhite lacquers were prepare~' according to Use Example 1 and applied by spraying to degreased stee~ p~ates.
The ~hite ~acquer fiLms uere baked a~ 150C for 30 minutes in an oven heated by c;rculating air. The films ~ere free ~0 of pits and had a Layer th;ckness of 40 to 60 ~m. The lacquer f;lms exhib;ted a good gloss and good leveling.
The values obtained in pa;nt tests are recorded in Table 1.
Table 1:
~inder Copolymer d;spersion according tP Example 1 i 2 3 4 Layer th;ckness (~m) 45 40 50 ~5 Fat resistanceX O ~
Pendulum hardness according to DTN 53,157 ts) 160 170 175 165 Gloss accord;ng to DI~' 67,53U (%) 9~ 90 88 92 Xylene testXx (min~ 30 30 30 30 ~ater testXx th) 1,450 800 7502r200 .. _ .. ~.. _A _._ .. _ .. _ _.1_.. _ ._ _ . A_ _ _ _ _ _ _ __ ._ . _ _ _ ~ _ ... _ ~ . _.. _ _ .. _ . --~ Caustics test~X ~NaO~, 10%~ No attack after 96 hours -- . .
x : O = bes~ valwe~ 5 = worst value xx : ~ad of absorbent cotton test, as descr;bed.
Use Example 3 Preparat;on of double-layer metal-effect lacquers with the copoLymer d;spersion according to ~ . ~
~3~
Example 1:
'The base coat was composed of a mixture of 10.5 9 of oil-free polyestcr, 11.2 9 of cellulose acetobutyr-ate, 2.5 g of commercial non-plast;c;zed, reactive, part-;ally ether;f;ed melamine resin and 5 9 of alum;num p;gment.The m;xture ~as d;luted to a flo~ v;scometer time of 1~
seconds in a 4 mm DIN cup ~DIN 53,21i) ~ith a solvent mix-ture composed of xylene~ butyl acetate and ethylene glvsol ¦ monobutyl ether ~2:7:13. This base coat was ;nitially applied ;n a ~et-layer thickness of 100 ~m. After an air-;ng t;me of 3 m;nutes at room temperature~ the transparent lacquer top coat was applied, ~h;ch top coat ~as composed of 215 g of the copolymer dispers;on according to Example 1 and 11.7 9 ojf hexamethoxymethylmelamine and had been diluted to a fl~w v;sco~eter t;me of 18 sec~nds ;n a 4 mm DIN cup ~ith a mixture of ~ater and butylglycol ~9:
1~0 The double-layer metal-effect coatin~ ~as then cured at 150C for 30 minutes. The metal-effect lacquer tested in the "Florida test" still showed a good maintenance of gloss and resistance to chalkin~ after 12 months of exposure in Florida tfor details of the FLORIDA test, see the FArIPE~
Congress Report 1978, page 83).
Use Ex_mple 4 Preparation of a metal-effect lacquer based on the copolymer dispers;on according to Example 4.
For the preparation of a bas;c lacquer, a mixture of 6.5 9 of thermocett;ng acrylate res;n, which cross-links ~;th foreign material, 1.4 9 of a non-plasticized, reactive and p'artially ether;f;ed melam;ne resin and 6.8 9 ' ~%~3~4~
of alum;num p;gment ~ere homogeneously mixed~ The mixture ~as then diluted to a flow viscometer time of 15 seconds in a 4 mm DIN cup ~DIN 53,211) ~ith a solvent mixture com-posed of xylene and butyl acetate t1:1). The lacquer nix-ture was appLied to alum7num bonders and aired for 2 minutes,Then the transparent lacquer top coat, ~hich ~as composed of a mixture of 180 9 of ehe copolymer dispersion accord-ing to Example 4 and 9.2 9 of hexamethoxymethylmelamine and uhich had been diluted to a flo~ viscometer time of 1b seconds in a 4 m~ DIN cup w;th a mixture of water and butylglycol t8:2), was applied. This ~etal-effect coat-ing prepared by the "~et-in-~et process" ~as then cured at 140C for 20 minutes. The metal-effect lacquers tested ;n the "Florida test" showed good ~loss maintenance and chalking resistance after 12 months.
Compar;son Example A
An aqueous copolymer dispersion ~as prepared accord-;ng to Example 1 Qf German Offen(egungsschrift 2,7D9,3Q~, and this ~as processed to g;ve a ~hite lacquer accord ns to Use E~ample 1 accord;ng to the invention. Th;s white lacquer ~as sprayed onto degrease~ steel plates and baked at 150C for 30 m;nutes. The water-resistance of this lacquer film ~as tested by the wad of absorbent cotton test method. The maxinum test values ob~a;ned ~ere 120 hours~
The clear aqueous res;n solution was employed in th;s form as a p;gment-~etting agent.
Use Example 2 ~ . .
Preparat;on of white lacquer pa;nts based on the copolymer d;spersions according to Examples 1, Z, 3 and It and the pigment wetting agent according to Example 5:
A. Pigment paste 20.60 g of t;tanium d;ox;de (rutile type~
6.25 g of hexamethoxymethylmelamine 7.80 9 of pigment-wett;ng agent tExamp~e 5) and 0.2Q g of commer5ial uetting agent 7~ .
~3~3 .
B. Binder 55.45 9 of copo~ymer dispers;on according to Examples 1, 2, 3 and 4 ~.55 9 of pigment-wett;ng agent tExample 53 and S 0.15 8 of commercial corros;on ;nh;bitor.
Uhite lacquers were prepare~' according to Use Example 1 and applied by spraying to degreased stee~ p~ates.
The ~hite ~acquer fiLms uere baked a~ 150C for 30 minutes in an oven heated by c;rculating air. The films ~ere free ~0 of pits and had a Layer th;ckness of 40 to 60 ~m. The lacquer f;lms exhib;ted a good gloss and good leveling.
The values obtained in pa;nt tests are recorded in Table 1.
Table 1:
~inder Copolymer d;spersion according tP Example 1 i 2 3 4 Layer th;ckness (~m) 45 40 50 ~5 Fat resistanceX O ~
Pendulum hardness according to DTN 53,157 ts) 160 170 175 165 Gloss accord;ng to DI~' 67,53U (%) 9~ 90 88 92 Xylene testXx (min~ 30 30 30 30 ~ater testXx th) 1,450 800 7502r200 .. _ .. ~.. _A _._ .. _ .. _ _.1_.. _ ._ _ . A_ _ _ _ _ _ _ __ ._ . _ _ _ ~ _ ... _ ~ . _.. _ _ .. _ . --~ Caustics test~X ~NaO~, 10%~ No attack after 96 hours -- . .
x : O = bes~ valwe~ 5 = worst value xx : ~ad of absorbent cotton test, as descr;bed.
Use Example 3 Preparat;on of double-layer metal-effect lacquers with the copoLymer d;spersion according to ~ . ~
~3~
Example 1:
'The base coat was composed of a mixture of 10.5 9 of oil-free polyestcr, 11.2 9 of cellulose acetobutyr-ate, 2.5 g of commercial non-plast;c;zed, reactive, part-;ally ether;f;ed melamine resin and 5 9 of alum;num p;gment.The m;xture ~as d;luted to a flo~ v;scometer time of 1~
seconds in a 4 mm DIN cup ~DIN 53,21i) ~ith a solvent mix-ture composed of xylene~ butyl acetate and ethylene glvsol ¦ monobutyl ether ~2:7:13. This base coat was ;nitially applied ;n a ~et-layer thickness of 100 ~m. After an air-;ng t;me of 3 m;nutes at room temperature~ the transparent lacquer top coat was applied, ~h;ch top coat ~as composed of 215 g of the copolymer dispers;on according to Example 1 and 11.7 9 ojf hexamethoxymethylmelamine and had been diluted to a fl~w v;sco~eter t;me of 18 sec~nds ;n a 4 mm DIN cup ~ith a mixture of ~ater and butylglycol ~9:
1~0 The double-layer metal-effect coatin~ ~as then cured at 150C for 30 minutes. The metal-effect lacquer tested in the "Florida test" still showed a good maintenance of gloss and resistance to chalkin~ after 12 months of exposure in Florida tfor details of the FLORIDA test, see the FArIPE~
Congress Report 1978, page 83).
Use Ex_mple 4 Preparation of a metal-effect lacquer based on the copolymer dispers;on according to Example 4.
For the preparation of a bas;c lacquer, a mixture of 6.5 9 of thermocett;ng acrylate res;n, which cross-links ~;th foreign material, 1.4 9 of a non-plasticized, reactive and p'artially ether;f;ed melam;ne resin and 6.8 9 ' ~%~3~4~
of alum;num p;gment ~ere homogeneously mixed~ The mixture ~as then diluted to a flow viscometer time of 15 seconds in a 4 mm DIN cup ~DIN 53,211) ~ith a solvent mixture com-posed of xylene and butyl acetate t1:1). The lacquer nix-ture was appLied to alum7num bonders and aired for 2 minutes,Then the transparent lacquer top coat, ~hich ~as composed of a mixture of 180 9 of ehe copolymer dispersion accord-ing to Example 4 and 9.2 9 of hexamethoxymethylmelamine and uhich had been diluted to a flo~ viscometer time of 1b seconds in a 4 m~ DIN cup w;th a mixture of water and butylglycol t8:2), was applied. This ~etal-effect coat-ing prepared by the "~et-in-~et process" ~as then cured at 140C for 20 minutes. The metal-effect lacquers tested ;n the "Florida test" showed good ~loss maintenance and chalking resistance after 12 months.
Compar;son Example A
An aqueous copolymer dispersion ~as prepared accord-;ng to Example 1 Qf German Offen(egungsschrift 2,7D9,3Q~, and this ~as processed to g;ve a ~hite lacquer accord ns to Use E~ample 1 accord;ng to the invention. Th;s white lacquer ~as sprayed onto degrease~ steel plates and baked at 150C for 30 m;nutes. The water-resistance of this lacquer film ~as tested by the wad of absorbent cotton test method. The maxinum test values ob~a;ned ~ere 120 hours~
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the preparation of an aqueous dispersion of a copolymer which can be crosslinked with an aminoplast resin by the action of heat and which is prepared by copolymerization of monomers from the group comprising styrene, esters of acrylic acid, esters of methacrylic acid, vinyl esters, monoolefinic unsaturated monomers having hydroxyl groups, acrylic acid, methacrylic acid, unsaturated amides and other functional comonomers, in an aqueous phase in the presence of a radical-forming initiator and an anionic emulsifier, which comprises copolymerizing a mixture of 30 to 60 parts by weight of styrene and/or ethyl meth-acrylate, 20 to 50 parts by weight of an ester of acrylic acid or of methacrylic acid, the homopolymer of which has a glass tempera-ture TG below +50°C, or a mixture of these esters, 5 to 30 parts by weight of a vinyl ester of a branched saturated monocarboxylic acid, which has side chains having 8 to 12 carbon atoms and in which the carboxyl group is on a tertiary carbon atom, 5 to 15 parts by weight of a hydroxyalkyl ester of a monoolefinic unsaturated monocarboxylic acid, 0.5 to 15 parts by weight of an .alpha.,.beta.-unsaturated monocar-boxylic acid and/or unsaturated dicarboxylic acid, 0.1 to 8 parts by weight of an addition product of a glycidyl ester of a branched monocarboxylic acid with an unsaturated monocarboxylic or dicarboxylic acid, and 0.1 to 5 parts by weight of an unsaturated amide.
2. A process as claimed in claim 1 wherein the anionic emulsifier is an alkali metal salt of the hemisulfates of alkyl-phenols or alcohols and the hemisulfates of oxethylated alkyl-phenols or oxethylated alcohols or an alkali metal salt of an alkylsulfonate or an arylsulfonate, or mixtures thereof.
3. A process as claimed in claim 1 wherein a non-ionic emul-sifier of the type of an ethoxylated alkylphenol or fatty alcohol is employed to increase the stability of the aqueous copolymer dispersion.
4. A coating composition which comprises an aminoplast resin and an aqueous copolymer dispersion prepared by a process according to claim 1, 2 or 3 or an obvious chemical equivalent thereof.
5. A process of coating a substrate which comprises applying to the substrate a coating composition composed of an aminoplast resin and an aqueous copolymer dispersion prepared by a process according to claim 1, 2 or 3 or an obvious chemical equivalent thereof, and crosslinking the composition to form the required coating.
6. In a process for coating the surface of a substrate, the improvement which comprises the use of the copolymer dispersion obtained by the process of claim 1, 2 or 3 for the preparation of coatings which can be crosslinked with an aminoplast resin by the action of heat.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19813128062 DE3128062A1 (en) | 1981-07-16 | 1981-07-16 | AQUEOUS COPOLYMERISAT DISPERSIONS, METHOD FOR THE PRODUCTION AND USE OF THE DISPERSIONS |
| DEP3128062.5 | 1981-07-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1230443A true CA1230443A (en) | 1987-12-15 |
Family
ID=6137023
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000407389A Expired CA1230443A (en) | 1981-07-16 | 1982-07-15 | Process for the preparation of an aqueous copolymer dispersion and the use of the dispersion |
Country Status (14)
| Country | Link |
|---|---|
| US (1) | US4522972A (en) |
| EP (1) | EP0071070B1 (en) |
| JP (1) | JPS5819302A (en) |
| AT (1) | ATE9484T1 (en) |
| AU (1) | AU8605982A (en) |
| BR (1) | BR8204133A (en) |
| CA (1) | CA1230443A (en) |
| DE (2) | DE3128062A1 (en) |
| DK (1) | DK318682A (en) |
| ES (1) | ES8305013A1 (en) |
| FI (1) | FI822505L (en) |
| NO (1) | NO822457L (en) |
| PT (1) | PT75261B (en) |
| ZA (1) | ZA825032B (en) |
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| CA1230198A (en) * | 1982-07-26 | 1987-12-08 | Joseph V. Koleske | High solids primer-guidecoats based on t-butyl acrylate and styrene |
| CA1230199A (en) * | 1982-08-05 | 1987-12-08 | Joseph V. Koleske | Highly weatherable coatings |
| DE3410234A1 (en) * | 1984-03-21 | 1985-10-03 | Hoechst Ag, 6230 Frankfurt | AQUEOUS DISPERSIONS FOR THE PRODUCTION OF CROSSLINKABLE COATINGS |
| GB2172292A (en) * | 1985-03-08 | 1986-09-17 | Mitsubishi Rayon Co | Acrylic copolymer coatings |
| US4980410A (en) * | 1985-05-10 | 1990-12-25 | E. I. Du Pont De Nemours And Company | Acrylic copolymer composition and adhesive coatings therefrom |
| US4975484A (en) * | 1985-05-10 | 1990-12-04 | E. I. Du Pont De Nemours And Company | Acrylic copolymer composition and adhesive coatings therefrom |
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| US4855402A (en) * | 1985-11-25 | 1989-08-08 | The Goodyear Tire & Rubber Company | Self-emulsifiable resin powder |
| IN166663B (en) * | 1985-11-25 | 1990-06-30 | Goodyear Tire & Rubber | |
| DE3544337A1 (en) * | 1985-12-14 | 1987-06-19 | Hoechst Ag | POLYMERISAT DISPERSIONS, METHOD FOR THE PRODUCTION THEREOF AND THEIR USE AS BINDERS |
| US4782109A (en) * | 1986-06-26 | 1988-11-01 | Lindsay Finishes, Incorporated | Latex paint formulations and methods |
| DE3628124A1 (en) * | 1986-08-19 | 1988-03-03 | Herberts Gmbh | AQUEOUS COATING AGENT, METHOD FOR THE PRODUCTION THEREOF AND THE USE THEREOF |
| EP0289997B1 (en) * | 1987-05-08 | 1994-01-12 | Herberts Gesellschaft mit beschränkter Haftung | Coating composition and its use in the preparation of multi-layer coatings |
| DE3827587A1 (en) * | 1988-08-13 | 1990-03-01 | Basf Lacke & Farben | COPOLYMERISATES CONTAINING AMINO, METHOD FOR THEIR PRODUCTION AND THEIR USE IN COATING AGENTS |
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| US5116407A (en) * | 1988-10-13 | 1992-05-26 | Courtaulds Coatings Limited | Antifouling coatings |
| CA2014539C (en) * | 1989-04-17 | 2000-07-25 | Shinichiro Umeda | Water borne metallic coating composition |
| US5124393A (en) * | 1989-08-29 | 1992-06-23 | Union Oil Company Of California | Latex paints |
| US5213901A (en) * | 1989-08-29 | 1993-05-25 | Rohm And Haas Company | Coated articles |
| US5227423A (en) * | 1989-08-29 | 1993-07-13 | Rohm And Haas Company | Paints and binders for use therein |
| US5219917A (en) * | 1989-08-29 | 1993-06-15 | Rohm And Haas Company | Latex-paints |
| US5212225A (en) * | 1989-08-29 | 1993-05-18 | Rohm And Haas Company | Binder synthesis process |
| US5134186A (en) * | 1989-08-29 | 1992-07-28 | Union Oil Company Of California | Latex paints |
| US5157071A (en) * | 1989-08-29 | 1992-10-20 | Union Oil Company Of California | Paints and polymers for use therein |
| GB8924983D0 (en) * | 1989-11-06 | 1989-12-28 | Shell Int Research | Interpolymer latices from esters of(meth)acrylic acid and vinyl esters of branched chain carboxylic acids |
| GB8924984D0 (en) * | 1989-11-06 | 1989-12-28 | Shell Int Research | Interpolymer latices from esters of(meth)acrylic acid and vinyl esters of branched chain carboxylic acids |
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| GB9024753D0 (en) * | 1990-11-14 | 1991-01-02 | Shell Int Research | Interpolymer latices from esters of(meth)acrylic acid and vinyl esters of branched chain carboxylic acids |
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| US5425972A (en) * | 1993-04-16 | 1995-06-20 | Westvaco Corporation | Heat sealed, ovenable food carton lids |
| US5418008A (en) * | 1993-04-16 | 1995-05-23 | Westvaco Corporation | Method for producing barrier packaging |
| US5985979A (en) * | 1993-07-20 | 1999-11-16 | Shell Oil Company | Process for making stable latexes of block copolymers |
| DE4332012A1 (en) * | 1993-09-21 | 1995-03-23 | Roehm Gmbh | PSA dispersions |
| US5484840A (en) * | 1993-12-21 | 1996-01-16 | Binkley; Jesse A. | Textile sizes containing ultrafine-sized aqueous polymeric dispersions |
| DE4419216C1 (en) * | 1994-06-01 | 1995-08-31 | Bollig & Kemper | Aq. clearcoat compsn. for multilayer paint systems |
| US5660898A (en) * | 1995-08-28 | 1997-08-26 | Westvaco Corporation | Heat sealed, ovenable food cartons |
| US5855973A (en) * | 1995-08-28 | 1999-01-05 | Westvaco Corporation | Heat sealed, ovenable food cartons and lids |
| DE19621574A1 (en) * | 1996-05-29 | 1997-12-04 | Basf Ag | Binder for low-emission coating materials |
| US6136443A (en) * | 1997-07-11 | 2000-10-24 | Ppg Industries Ohio, Inc. | Acid etch resistant film-forming compositions and composite coating compositions |
| US6498202B1 (en) * | 1999-12-14 | 2002-12-24 | Lexmark International, Inc | Ink jet ink compositions including latex binder and methods of ink jet printing |
| US6683129B1 (en) * | 2000-03-31 | 2004-01-27 | National Starch And Chemical Investment Holding Corporation | Salt sensitive aqueous emulsions |
| JP2003334902A (en) * | 2002-05-17 | 2003-11-25 | Toyobo Co Ltd | Easily adhesive stretched film of syndiotactic polystyrene |
| JP6648938B2 (en) * | 2016-03-16 | 2020-02-14 | 関西ペイント株式会社 | Paint composition |
| CN110054976B (en) * | 2019-04-19 | 2020-11-20 | 华南理工大学 | Aqueous hydroxy acrylic acid dispersoid modified by multi-heterocyclic acrylate monomer and preparation method thereof |
| CN114031712A (en) * | 2021-11-02 | 2022-02-11 | 张珂 | Water-based hydroxyl acrylic resin molecular composition and synthesis method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1565529A1 (en) * | 1966-02-18 | 1970-04-16 | Karl Fischer | Hotplate with thermal control |
| DE2626900C2 (en) * | 1976-06-16 | 1978-04-13 | Hoechst Ag, 6000 Frankfurt | Process for the production of copolymers containing hydroxyl groups |
| DE2850872A1 (en) * | 1978-11-24 | 1980-06-04 | Bayer Ag | WATER-DUMBABLE VARNISH BINDERS FOR CHEMICAL-RESISTANT COATINGS |
| US4395499A (en) * | 1982-09-13 | 1983-07-26 | National Starch And Chemical Corporation | High strength pigment binders for paper coatings containing carboxylated vinyl ester alkyl acrylic interpolymers |
-
1981
- 1981-07-16 DE DE19813128062 patent/DE3128062A1/en not_active Withdrawn
-
1982
- 1982-07-09 ES ES513834A patent/ES8305013A1/en not_active Expired
- 1982-07-13 DE DE8282106240T patent/DE3260783D1/en not_active Expired
- 1982-07-13 AT AT82106240T patent/ATE9484T1/en active
- 1982-07-13 EP EP82106240A patent/EP0071070B1/en not_active Expired
- 1982-07-14 FI FI822505A patent/FI822505L/en not_active Application Discontinuation
- 1982-07-14 US US06/398,415 patent/US4522972A/en not_active Expired - Fee Related
- 1982-07-15 BR BR8204133A patent/BR8204133A/en unknown
- 1982-07-15 CA CA000407389A patent/CA1230443A/en not_active Expired
- 1982-07-15 AU AU86059/82A patent/AU8605982A/en not_active Abandoned
- 1982-07-15 JP JP57122258A patent/JPS5819302A/en active Pending
- 1982-07-15 ZA ZA825032A patent/ZA825032B/en unknown
- 1982-07-15 PT PT75261A patent/PT75261B/en unknown
- 1982-07-15 DK DK318682A patent/DK318682A/en not_active Application Discontinuation
- 1982-07-15 NO NO822457A patent/NO822457L/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| EP0071070B1 (en) | 1984-09-19 |
| DK318682A (en) | 1983-01-17 |
| FI822505A0 (en) | 1982-07-14 |
| FI822505L (en) | 1983-01-17 |
| BR8204133A (en) | 1983-07-12 |
| JPS5819302A (en) | 1983-02-04 |
| ATE9484T1 (en) | 1984-10-15 |
| ES513834A0 (en) | 1983-04-16 |
| ES8305013A1 (en) | 1983-04-16 |
| DE3128062A1 (en) | 1983-02-03 |
| EP0071070A1 (en) | 1983-02-09 |
| PT75261B (en) | 1985-01-07 |
| PT75261A (en) | 1982-08-01 |
| AU8605982A (en) | 1983-01-13 |
| US4522972A (en) | 1985-06-11 |
| DE3260783D1 (en) | 1984-10-25 |
| ZA825032B (en) | 1983-05-25 |
| NO822457L (en) | 1983-01-17 |
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