DE1942423A1 - Aqueous acrylic emulsions - Google Patents

Description

Dr. F. Zumsteln sen. - Dr. E. Assmann Dr. R. Koenlgsberger - Dlpl.-Phys. R. Holzbauer - Dr. F. Zumsteln Jun.

PATENT LAWYERS TELEPHONE: COLLECTIVE NO. 223341 β MÖNCHEN 2. TELEX S2BB70 BRÄUHAUSSTRASSE 4 /! Il

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BANK ACCOUNT: BANK H. AUFHAUSER

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Case No. CP. 4486

The Dunlop Company Limited, London S.W. 1

Aqueous acrylic emulsions.

The present invention relates to aqueous acrylic emulsions and their uses.

According to the present invention comprises an aqueous acrylic emulsion a polymerized acrylic resin containing at least 20% by weight acrylic acid ester or methacrylic acid ester, at least an emulsifier, a mercaptan and a water-soluble colloid containing one or more carboxyl groups.

The acrylic resin is a polymerized resin that is at least preferably 30% and even more preferably 50% by weight acrylic acid and / or methacrylic acid ester. Examples of suitable acrylic acid esters include methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and for examples suitable methacrylic acid esters include methyl methacrylate, ethyl methacrylate and n-butyl methacrylate. The ester doesn't have to must be the ester of a simple alcohol, it can

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for example be derived from an ether alcohol. Desired case 3 the ester can contain other groups.

If desired, other monomers can be incorporated into the resin

particularly preferred monomers are benzoid compounds

gene having a vinyl group in the side chain, for example, styrene, a- methyl styrene and vinyl toluene. Other monomers that can be used include ethyl acrylamide, acrylonitrile, ethylene vinyl ester, vinyl ether, vinyl chloride, vinylidene chloride, 1,2-olefins such as ethylene or propylene, and esters of furraric acid, itaconic acid and maleic acid. ·

The acrylic resin usually contains a minor amount of a polymerizable acid, such as itaconic acid, methacrylic acid, and acrylic acid, which is normally present in an amount of 1 to 5 percent by weight of the total monomer, but larger amounts can be used.

In addition, if desired, low Kengen crosslinking agents can be used are also polymerized (copolymerization), examples suitable crosslinking agents are bivinylbenzene, polyethylene glycol-dmethacrylate, Glycidyl methacrylate and Eydrocyäthylacrylat, and they can be incorporated where they can participate in crosslinking reactions with active groups that are present in the copolymers, such as carboxyl or hydroxyl groups. Alternatively or additionally, external crosslinking agents, such as aqueous melamine formaldehyde resin, can be used after Polymerization can be added.

The emulsifier can be an ionic or nonionic emulsifier, any of the known types of ionic or nonionic emulsifiers can be used; if desired, ionic and nonionic emulsifiers can be present. Examples of ionic emulsifiers include phosphate, phosphonate, sulfate and sulfonate groups-containing · emulsifier. If you want the emulsion to be corrosion-resistant

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a phosphated emulsifier is usually used used. Examples of particularly suitable phosphated emulsifying agents include the ammonium salts of Monoalkyl- and dialyl-phosphated esters, e.g. the ammonium salt of konolauryl and dilauryl phosphate esters or the ammonium as of mono- and di-polyethoxyalkyl phosphate esters, the be neutralized as necessary. Examples of suitable sulfate and sulfonate group-containing emulsifiers include Sodium or ammonium alkyl benzene or alkyl toluene sulfonate, e.g. the sodium salt of dodecylbenzenesulfonic acid or sodium lauryl sulfate. You can use ionic emulsifiers in an amount of up to 5 parts, better 2.5 parts by weight per 100 parts by weight of total monosieres.

Examples of suitable nonionic emulsifiers include polyethylene oxide ethers. The nonionic emulsifier can in a crowd up to i? Parts, better 2.5 parts by weight per 100 Parts by weight of total monomer may be present.

Surprisingly, it has been found that the inclusion of a mercaptan in the emulsion su leads to an additional stabilization of the emulsion.

The mercaptan can be, for example, an alkyl mercaptan having at least 6 and preferably at least 8 carbon atoms in the carbon chain, preferably 8 carbon atoms for each Sulfur atom in the molecule. A typical alkyl mercaptan that can be used is tert-dodecyl mercaptan. Alternatively, an alicyclic or aromatic mercaptan can be used. The mercaptan can be used in an amount of up to 4 parts, preferably 3 parts by weight per 100 parts by weight of total monomer be present.

The water-soluble colloid can be a copolymer in which one of the monomers is an acid * or an acid anhydride

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is, wherein the copolymer has an oxygen content of at least 30 wt .- ^, calculated for the acid form of the copolymer, and preferably the carboxyl or anhydride content of the colloid, except for the ester groups, expressed as direct COOH groups, should be at least 40 wt. -%. Particularly useful colloids are those formed from an acid or an acid anhydride in which the acid is an unsaturated acid in which two carboxyl groups are attached to the carbon atoms on either side of the unsaturated bond. The colloid should be water-miscible, even water-dispersible or water-swellable, for example, it should absorb at least its own weight in water, and it should be soluble in an alkali such as sodium hydroxide or ammonia, so that free acid groups, especially carboxyl groups The colloid is preferably _{of the type or} nature that it does not precipitate the emulsion or that the emulsion does not tend to precipitate at the pH of the polymerization, which, although it may fluctuate during the polymerization, during a substantial part of the reaction, depending on the influence of the polymerizable acid, it can be about 5.0. Particularly suitable copolymers are those based on maleic anhydride which are hydrolyzed to maleic acid in solution, e.g. ethylene / maleic anhydride copolymer as a 1: 1 copolymer. Other examples of suitable colloids are polyacrylic acid and polymethacrylic acid.

As is known in the art, certain acids or acid copolymers are used extremely easily hydrolysed or enter into intramolecular esterifications, especially in acids Colloid type is preferred in the method of the present invention not used, like the copolymers of vinyl acetate and maleic anhydride. ■

The water-soluble colloid is normally in an amount between 0.1 to 5 wt .- $, based on the total weight of the

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Emulsion, before. The colloid can be acidic or neutralized State may be used, however, it is believed that if an acidic comonomer, e.g., methacrylic acid, is used becomes, it is desirable to operate at an acidic pH in order to achieve good interpolymerization. The emulsion can later with ammonia, an amine or an alkali or - if necessary - be neutralized with another neutralizing agent.

The polymerization of the acrylic resin can expediently in the presence of sodium, potassium or ammonium persulphates or other, well-known initiators for radical polymerizations, including redox systems.

External plasticizers or temporarily used solvents can be included and before, during or after the polymerization be admitted.

Furthermore, in the context of the present invention, the emulsions with! fillers, pigments, thickeners ^ dispersants, Plasticizers, resinous materials and solvents are loaded so that a wide variety of products is obtained, including paints, adhesives, sealants, waterproofers and surface coatings. It is a general feature of the emulsions prepared according to the invention that, with regard to the direct addition, without preceding, separate grinding or wetting, of almost any pigment or filler are very stable, and these emulsions can be used as bald and wetting media for pigments and fillers can be used according to known methods.

These emulsions can also be incorporated into cement, concrete and plaster to improve one or more of the properties and modify.

A particularly useful aspect of the present invention is

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the one with a corrosion-inhibiting pigment of the emulsion is incorporated., do get a paint. Such a thing Pigment prevents or inhibits the corrosion mechanisms, which normally occur on surfaces susceptible to corrosion, such as steel.

Appropriate anti-corrosive pigments to be used are e.g. zinc tetroxychromate, strontium chromate, barium metaborate, Zinc potassium chromate, lead silicochronate, zinc molybdate or a co-precipitated zinc phosphate / zinc chromate.

"It is also possible to use other pigments or mixtures of pigments, such as to use red iron oxides or titanium dioxides. '

Other additives, such as colloid thickeners, for manufacture the pigment dispersion, dispersant and standard thickener can also be incorporated into the formulation of the paint. A suitable colloid that can be used is a Ethylene-potassium anhydride colloid, which has a high viscosity In the solution at low concentrations it gives it Easily networked during manufacture, for example.

If the paint is to be used for applications where corrosion resistance is required, the paint should preferably be buffered to ensure that it remains alkaline while drying. This serves to prevent corrosion, which would be promoted by the anesthesia in an acidic medium. Particularly suitable buffer systems for this purpose are relatively non-volatile ami- VSfä »B. Diethylaminoethanol, which can be used to keep the pS 4es system in the range of 8. The presence of a relatively non-volatile buffer in the paint ensures that the paint remains alkaline even during the 3 drying stages after the paint has been applied to a surface . This reduces the risk of ^" flawed" spot corrosion during the processing steps.

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In the production of glossy paints from emulsions is the pigment: binder ratio usually no greater than 1.0: 1.0, although a larger amount of pigment is also possible. "Binder" in this context means the total content of pesticides the emulsion.

The new emulsions of the present invention are very suitable for use as clearcoats, i.e. as corrosion resistant Base coats, which are beneficial as an undercoat, especially on steel. The paints can be used as gloss paints and as an all-purpose primer can be used, and they can be used for applications where corrosion resistance is required is.

The objects coated in this way can be air-dried or kurae time, or they can be baked with hotter Quickly air dried or other well known methods will.

The following examples illustrate the invention without it However, to restrict, all ropes are parts by weight:

Example I.

It became an emulsion using the following formulation prepares:

A. Water phase

Ethylene maleic anhydride (Monsanto 100

(EMA 11))

nicctionic emulsifier 100

Gafac RE610 (Phosphated Ionic

Emulsifier) 50

tert-dodecyl mercaptan 80

Ammonia 60

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Ammonium persulphate 40 Water 8060

The nonionic emulsifier is a mixed cetyl oleyl alcohol, which is condensed with 13 ethylene oxide units.

Gafac RE610 consists of phosphated, ethoxylated, mixed Alkyl mono- and diphosphates available from General Aniline and PiIm Corporation of Hew York.

The ethylene / Kaleinsäureanhydrid was dissolved at 90 ⁰ C, then cautiously gave after partial cooling, the ammonia added to give / received, the ammonium salt of the corresponding ethylene Maleinsäurepolynerisates. Anschllessend the remaining ingredients were added, the ammonium persulfate at eina? Temperature was added of 50 ⁰ C. The tert-dodecyl mercaptan was dispersed in the Viasser phase.

B. Monomeric phase

(.i) Butyl Acrylate 5200

(ii) methyl methacrylate 4600 (iii) methacrylic acid '200

(ii) and (iii) were mixed together and 200 parts of the mixture obtained for V / A asserphase given after it was heated to 78 to 80 ⁰ C. After mixing, the remainder of B was added to phase A over a period of 3 hours at 78 to 80 ^° C., and the following was added at the same time:

Ammonium persulphate 20th ammonia 60 water 1000

The mixture was then heated to a temperature of 86 to 90 ^° C. for 20 minutes.

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The emulsion, which is stored in a normal reaction vessel, equipped with steam or hot water heating and water cooling, Stirrer and condenser, which had been made, was made with ammonia adjusted to pH 9. The emulsion had a particle size of about 0.2 microns and had a solids content of $ 51.8. The emulsion exhibited satisfactory thixotropy and had an apparent Brookfield ITr viscosity. 3, fluctuating between 33.4 poises and 8.5 poises, depending on the selected speed. Luster and purity of the dried Films were good.

It was also found that when the amount of methacrylic acid is increased to 4 ζ »by weight of the acrylic resin by decreasing it the amount of methyl methacrylate, the emulsion has desirable properties reveals, for example, it increases the gloss of the resulting paints.

Example II

This example describes the pigmentation of those used in Example I. prepared emulsion so that a base coat suitable for coating steel is obtained. The following connections were mixed together and then ground:

Zinc tetroxychromate 635

(crushed in the jet mill! mi cronised)

"Spain oxide" (iron oxide) 15007 363 Barite ( crushed in the jet mill; micronised) 365

Pearl white 455

Ethylene / maleic anhydride

(2.25 # solution)

(EMA 61 ) _t (as ammonium salt) 400

Oellofas B1500 (2 # solution), (Terdicker) 80 Oalgon PI (10 # solution),

(Dispersant) "109

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liatrium nitrite 4

Sodium benzoate 38

Water 608

Cellofas B1500 is a liatric salt of carboxymethyl cellulose, available from I.C.I.Ltd.

Calgon PT is a potassium polyphosphate available from I.C.I. Ltd.

To the above mixture they added:

Triethanolamine 100

Emulsion of Example I 6925

This resulted in a paint with a pigment / binder ratio of 0.5: 1 and a total solids of $ 54.5. The paint had a pH of 8.6 and was adjusted to pH 9 to 9.25 with concentrated ammonia.

An alternative formulation contained Vincofas X 100,000 as Ammonium salt in the same concentration as EMA

Example III

This example is the same as Example I with the exception that the Monomers have been replaced by the following formulation:

Methacrylic acid 400 Styrene 4500 Methyl methacrylate 600 Butyl acrylate 4500

The methacrylic acid was separated with the methyl methacrylate as in example I mixed · ', - ■ - ■ =' ".-

The finished emulsion was very much that made in Example I. similar and had a pesticide content of $ 52, a particulate

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size of 0.5 microns and a Brookfield Ur. 4-viscosity, varying between 422 poises and 76 poises, depending on the one chosen Speed.

IV

This example describes the pigmentation of the in Example III prepared emulsion so that a paint is obtained that can be used as a gloss finish. i) the following connections were mixed together and ground:

Titanium dioxide (grade RCR3) 1000

Calgon ΡΪ (10 ^ solution) 33

Hope ο DD72 (defoamer)

(lO ^ i solution) 15

V / ater 250

Emulsion from Example III 600 Tributylphosphaf 49

Nopco 13D72 is at ilopco Hess Ltd. available.

To the above mixture one added:

Water 390

Emulsion of Example III 2600

When applied with a brush or by any standard method, the resulting glossy paint produced a film on drying with good shine.

Example V

It became an emulsion using the following formulation manufactured:

A. barrel phase

Polyacrylic acid

(Viscosity of a 15.5 # solution at 20 ^° C. using a Brookfield spindle 1 at 30 rpm was 37.4 cps (pH 1.7)

Gafac RE610 0.5

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llonylphenyl, condensed with 7 ethylene oxides 1fO

tert-dodecyl mercaptan 0.8

Ammonium persulfate 0.4

Water 80

The Beetandteile were mixed together except that ammonium persulfate was added at 55 ⁰ C after the pH had been the mixture with ammonia adjusted to 5.8. The temperature was then raised to 60 ⁰ C.

B. Monomeric phase

Butyl acrylate 52

Methyl methacrylate 46

Methacrylic acid 2

^{The monomer phase was added to the water phase at 80 °} C. over the course of 3 hours, and the following compounds were added at the same time:

Water 10

Ammonium persulfate 0.2

Ammonia (conc.) 0.75

The following compounds were then added and the mixture was ^{heated to 88 °} C. for 1 hour:

Ammonium persulfate 0.1

Water 1.0

The emulsion had a particle size of about 0.5 microns.

Example VI '

An emulsion was made with the following formulation:

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A. Water phase

Polymethaeric acid (as sodium salt) (Viscosity 67.2 cps at 20 ° C using a Brookfield spindle 1 at 30 rpm) 1.0 Gafac KB610 0.5 nonylphenol, condensed with 7 ethylene oxides 1.0 tert-dodecyl mercaptan 0.8 ammonium per sulfate 0.4 Water 80

The additives were dissolved together, except that ammonium persulfate was added at 55 ⁰ C, the pH was naohdem the mixture with ammonia adjusted to 5.8. The temperature was then raised to 60 ^° C.

B. Monomeric Phase As in Example V.

added the monomer phase in the course of 3 hours at 80 ^° C. to the water phase and at the same time added the following compounds:

Water 10

Ammonium persulfate 0.2 Ammonia (conc.) 0.75

Finally, the following compounds were added and the mixture was ^{heated to 88 °} C. for 1 hour!

Ammonium persulfate 0.1

Water 1.0

The emulsion so prepared was stable, had a particle size of 0.25 microns and gave a clear and glossy one PiIm.

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Claims (32)

Claims 1. Aqueous acrylic enrol s ion, characterized in that it is a polymerisiert.Acrylharz, the at least 20 wt .-? S acrylic acid ester or methacrylic acid ester contains at least one emulsifier, a mercaptan and a water-soluble colloid, which contains one or more Karoo ns acid groups. 2. Emulsion according to claim 1, characterized in that the Acrylic resin at least 30% by weight acrylic acid ester or methacrylic acid ester contains. - 3. Emulsion according to claim 2, characterized in that the acrylic resin contains at least 50 wt. - ^c p acrylic acid ester or methacrylic acid ester. . 4. Emulsion according to claim 1, 2 or 3, characterized in that the acrylic acid ester is ethyl acrylate, ethyl acrylate, n-butyl acrylate or 2-ethylhexyl acrylate. 5. Emulsion according to claim 1, 2 or 3, characterized in that t that the methacrylic acid ester is methyl methacrylate, ethyl methacrylate or n-butyl methaorylate. 6. Eoulsioli according to one of the preceding claims, characterized in that the acrylic resin contains a benzoid compound. _ ■; - "/ -", ''".". ~ '"- _ \. ', '. ■ ..-- ;. 7. Emulsion according to claim 6, characterized in that the benzoid compound styrene, OC -methylstyrene or vinyl toluene 8. Emulsion according to one of the preceding claims, characterized in that the acrylic resin <e% & e polymerizable acid ^Λ ■ ■ ■ '-' ■■ ' ^: "· ■ ^: - ■ ■ ^; k: ^ - A ..; "> ■■ '.. ■" otf ^ 809 / i2.3i;' ^ _/: ^ contains 5% by weight of the total monomer in a Henge of 1 mg. 9. Emulsion according to claim 8, characterized in that the polymerizable acid itaconic acid, methacrylic acid or acrylic acid. 10. Emulsion according to one of the preceding claims, characterized in that 'an ionic and a nonionic Emulsifiers are present. 11. Emulsion according to claim 10, characterized in that the ionic emulsifier in an amount of up to 5 parts by weight is present per 100 parts by weight of total monomer. 12. Emulsion according to claim 11, characterized in that the ionic emulsifier in an amount of up to 2.5 parts by weight is present per 100 parts by weight of total monomer. 13. Emulsion according to claim 10, 11 or 12, characterized in that the emulsifier contains phosphate or phosphonate groups Contains groupings. 14. Emulsion according to claim 10, 11 or 12, characterized in that the emulsifier contains sulfate or sulfonate groups Contains groupings. 15. Emulsion according to one of claims 10 to 14 »characterized in that that the nonionic emulsifier in an amount of up to 5 parts by weight per 100 parts by weight of total monomer is available. 16. Emulsion according to claim 15, characterized in that the nonionic emulsifiers in an amount up to 2.5 Parts by weight per 100 parts by weight of total monomer is present. 009809/1238 17. Emulsion according to one of claims 10 to 16, characterized in that that the nonionic emulsifier is a polyethylene oxide ether. 18. Emulsion according to one of the preceding claims, characterized in that the mercaptan in an amount of up to is present at 4 parts by weight per 100 parts by weight of total monomer. 19. Emulsion according to claim 18, characterized in that the. κ mercaptan is present in an amount of up to 3 parts by weight per 100 parts by weight of total monomer. 20. Emulsion according to one of the preceding claims, characterized characterized in that the mercaptan is an alkyl mercaptan having at least 6 carbon atoms in the carbon chain. 21. Emulsion according to claim 20, characterized in that the alkyl mercaptan has at least 8 carbon atoms in the carbon chain owns. 22. Emulsion according to claim 21, characterized in that the mercaptan is tert-dodecyl mercaptan. 23. Emulsion according to one of the preceding claims, characterized characterized in that the water-soluble colloid is formed from an unsaturated acid in which two carboxyl groups to the carbon atoms on either side of the unsaturated ones Bond are bound. 24. Emulsion according to one of the preceding claims, characterized in that the water-soluble colloid is a copolymer is, in which one of the monomers is an acid or an acid aniihydride, the copolymer is a Oxygen content of at least 30% by weight, calculated for 00 9 80 9/1 2 3.8 the copolymer in the acid form possesses. 25. Emulsion according to one of the preceding claims, characterized characterized in that the water-soluble colloid is an ethylene / maleic anhydride copolymer as a 1: 1 copolymer is. 26. Emulsion according to one of claims 1 to 23, characterized in that that the water-soluble colloid is polyacrylic acid or polymethacrylic acid. 27. Emulsion according to one of the preceding claims, characterized in that the water-soluble colloid in one Amount from 0.1 to 5 wt .- / 6, based on the total weight the emulsion is present. 28. Emulsion according to one of the preceding claims, characterized in that the emulsion contains a pigment. 29. Emulsion according to claim 28, characterized in that the pigment is an anti-corrosive pigment. 30. Emulsion according to claim 29, characterized in that the * Pigment zinc tetroxychromate, zinc molybdate, strontium chromate, Lead silica chromate or a co-precipitated zinc phosphate / zinc chromate is. 31. Emulsion according to one of the preceding claims, characterized in that the emulsion is buffered, thus guaranteed is that it remains alkaline as it dries. 32. Clear coating composition useful as a base coat for steel, characterized in that it is an emulsion according to any one of claims 1 to 27. 009809/1 238