IE43518B1 - Paints on the basis of aqueous plastics dispersions - Google Patents

Abstract

Polymer dispersions prepared by polymerising olefinically unsaturated monomers in an aqueous medium and containing in the polymer portion a comonomer of a polymerisable acetoacetic ester are used as binders (vehicles) in low-pigmented, solvent-containing paints. The paints obtained have good wet adhesion.

Description

This invention relates to aqueous dispersion paints.

The problem of the wet adhesion, i.e. the adhesion of dried paints on wetting, of dispersion paints on smooth non-absorbent surfaces has long restricted the use of such dispersion paints. Dispersion paints having a low pigment content, which dry on the substrate with formation of a glossy or slightly dull film, have a poor adhesion to smooth non-absorbent surfaces when the paints are re-wetted after drying. The wet adhesion is especially unsatisfactory with fresh paints which have not yet undergone ageing.

Dispersion paints of low pigment content are chosen when a washable coat of paint is desired. Owing to the high binder content of the paint a non-porous washable film is formed. Dispersion paints drying with formation of a glossy or slightly dull film also have a pigment content of less than 40% by volume generally from about 10 to 25%. They also contain about 3 to 20% of organic solvent to improve the gloss and flow, to prolong the working time and for improving film consolidation, for example water- miscible polyhydric alcohols having up to 6 carbon atoms, especially ethylene and propylene glycols, or the monomethyl to monobutyl ethers thereof. To improve the film consolidation, there are used solvents having a restricted solubility in water> such as the monoglycol ethers of carboxylic acids and more particularly esters of carboxylic acids with mono43518 - 3 alkyl ethers of glycols or oligoglycols. Butyl di-glycol acetate is one of the most widely used representatives of this group. The combination of a low pigment content with a relatively high solvent content has a very detrimental effect on the wet adhesion of the coats of dispersion paints.

With poor wet adhesion, paints formulated to give washable coats do not have this property when applied to smooth non-absorbent surfaces, for example old coats of alkyd or oil paint. In moist rooms, such as kitchens, bath rooms, or industrial premises, where condensation may form, the new coat may detach from the substrate if the wet adhesion is insufficient. Moreover, poor wet adhesion complicates painting. When, for example, the base and the upper half of a wall or the wall and the ceiling are to be painted in different colours, the first coat of paint may be soiled with the different paint by inaccurate handling of the brush. In principle, the different paint could be wiped off with a wet cloth or sponge, but with a poor wet adhesion the first paint may then be damaged or even removed simultaneously.

Therefore, many attempts have been made to modify plastics dispersions in such a manner that the dispersion paints made therewith have the desired wet adhesion. Numerous monomers containing special functional groups (for example certain cycloureides, oxazolidines, azomethines and aziridines) have been proposed as comonomers for the emulsion polymerization in order to improve the wet adhesion of dispersion paints on non-absorbent substrates. In order to Improve wet adhesion, it has also been proposed to incorporate amino groups into the polymer chains of emulsion polymers in such a manner that comonomers having special reactive groups, for example oxirane groups or groups having nucleophilically substitutable halogen atoms are additionally used in the emulsion polymerization and - 4 the amino groups are introduced into the polymer system only after complete polymerization by reaction with ammonia or amines.

Dispersion paints containing such amino groupbearing polymers as binder, however, often have a tendency to yellowing. Moreover, the wet adhesion is only very slightly improved. Many of these paints, with low pigment contents, yield coatings having a sufficient adhesion on smooth, non-absorbent substrates, but if organic solvents are added to these paints, the coatings obtained therefrom have no wet adhesion whatsoever.

In British Patent Specification No. 1,307,131, there are described plastics dispersions, the polymer portion of which contains monomers having keto groups, via which cross5 linking with, for example, bicarboxylic acid - bis - hydrazides can be achieved. These dispersions are used, for example in textile finishing for the manufacture of sizing agents which are resistant to dry-cleaning, and in the paint industry for the manufacture of solvent-resistant paints. > The present invention is based on the observation that organic solvent-containing aqueous dispersion paints having low pigment contents and a high degree of wet adhesion can be obtained when the binder contains a copolymer of an acetoacetic acid ester.

The present invention therefore provides aqueous dispersion paints comprising an organic liquid, from 7 to 30%, preferably from 10 to 20% by volume of a pigment, and as binder or part of a binder system, a copolymer containing from 0.5 to 10% by weight, relative to all monomer units in the binder or binder system, of units derived from an olefinically unsaturated acetoacetic acid ester, and units derived from at least one other olefinically unsaturated monomer.

The olefinically unsaturated acetoacetic acid ester is preferably vinyl acetoacetate, allyl acetoacetate or a diester of the formula R-CH=C-C-0 II •A-C-CH.

II C-CH in which S is H or CH^; A is or (CH2—cH2)m— 0—— n is an integer from 1 to 4 and m is an integer Of from 1 to 3. Acetoacetic acid allyl esters are especially preferred.

The binders of the paints of the present invention may be derived from a single co-polymer dispersion, or from a mixture of any two or more dispersions; when a mixture of dispersions is used, at least one must contain a copolymer of the acetoacetic acid ester units in such an amount that, relative to the weight of all monomer units in the binder system, the acetoactic acid ester units are present in an amount of from 0.5 to 10%, preferably from 1 to 5%.

The organic liquid constituent of the paints in accordance with the present invention is a glycol or a derivative thereof, for example ethyleneglycol, propyleneglycol, butyleneglycol, hexyleneglycol, an oligoglycol such as dior triglycol, a glycol or oligoglycol ether such as methyl, ethyl, propyl or butyl mono- di- or triglycol ether, a mono-, di- or triglycol ester such as mono-, di- or triglycol acetate, propionate or butyrate, or an (oligo)glycol semiether/semiester, for example methyl, ethyl, propyl or butyl mono-, di- or triglycol acetate, propionate or butyrate. A mixture of any two or more such substances can also be used. The organic liquids are generally included in the paints in <33518 an amount of from 3 to 20% preferably from 5 to 15%, relative to the total weight of the paint. The aqueous plastics dispersion from which the binder component is derived, preferably has a solids content of from 20 to 70%, more preferably from 40 to 60%, by weight. Such aqueous plastics dispersions may be manufactured in the usual manner according to processes known to those skilled in the art.

The selection of the other monomers of the binder copolymers is not critical. All monomers generally used for making plastics dispersions which meet the practical requirements of components of dispersion paints are suitable, for example vinyl esters of organic carboxylic acids the acid moiety of which contains from 1 to 30, preferably from 1 to 20 carbon atoms, for example vinyl acetate and vinyl propionate, and vinyl esters of branched monocarboxylic acids having up to 20 carbon atoms, for example, vinyl isononanoate; esters of acrylic acid or methacrylic acid having from 1 to 30 and preferably 1 to 20 carbon atoms in the alcohol moiety, for example ethyl acrylate, isopropyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methylacrylate and butyl methacrylate; aromatic or aliphatic α-β-unsaturated hydrocarbons such as ethylene, propylene, styrene, and vinyltoluene; vinyl halides such as vinyl chloride; unsaturated nitriles such as acrylonitrile; diesters of maleic acid or fumaric acid, for example dibutyl maleate and dibutyl fumarate; and α-β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid and derivatives thereof, for example acrylamide and methacrylamide.

When selecting the monomers, the generally acknowledged conditions for the manufacture of dispersion paints must be borne in mind. Xn the first place, care should be taken that the polymers formed yield a coherent film under the drying conditions of the paint and the monomers for making copolymers should be selected in such a manner that, depending on the respective polymerization parameters, the formation of copolymers with the keto compounds can be expected. Some suitable monomers combinations are listed below: ethyl acrylate/methyl methacrylate/(meth-)acrylic acid/allyl acetoacetate; butyl acrylate/methyl methacrylate/(meth-)acrylic acid/allyl acetoacetate; isobutyl acrylate/methyl methacrylate/(meth-)acrylic acid/ allyl acetoacetate; - ethylhexyl acrylate/methyl methacrylate/(meth-)acrylic acid/allyl acetoacetate; ethyl acrylate/styrene/methyl methacrylate/(meth-)acrylic acid/allyl acetoacetate; butyl acrylate/styrene/methyl methacrylate/(meth-)acrylic acid/allyl acetoacetate; - ethylhexylhexyl acrylate/styrene/(meth-)acrylic acid allyl acetoacetate; vinyl acetate/butyl acrylate/allyl acetoacetate; vinyl acetate/dibutyl maleate/allyl acetoacetate; vinyl acetate/dibutyl fumarate/allyl acetoacetate; vinyl acetate/vinyl isononanoate/allyl acetoacetate; vinyl acetate/vinyl 2 - ethylhexanoate/allyl acetoacetate; vinyl acetate/vinyl ester of Versatic acid with 10 carbon atoms/allyl acetoacetate (the word Versatic is a registered Trade Mark); vinyl acetate/ethylene/allyl acetoacetate; vinyl acetate/ethylene/vinyl chloride allyl acetoacetate.

Plastics dispersions are extremely complex systems, and the manufacture of dispersions requires the application of great skill and experience. Departing from the established rules of emulsion polymerization may therefore adver4351® sely affect important properties, for example, water resistance, of the dispersion films or paint films. For these reasons the dispersions should not contain substantially more than the usual amounts of up to 3%, preferably up to 2%, of ionic emulsifiers or of up to 6%, preferably up to 4%, of non-ionic emulsifiers, relative to the weight of the polymer.

Suitable non-ionic emulsifiers are, for example, alkyl polyglycol ethers, such as the ethoxylation products of lauryl, oleyl or stearyl alcohol or of mixtures such as coconut fatty alcohol; alkyl-phenol polyglycol ethers such as the ethoxylation products of octyl- or nonyl-phenol, diisopropyi - phenol, triisopropyl-phenol or di- or tritert.butyl-phenol; or ethoxylation products of polypropylene oxide.

As ionic emulsifiers, anionic emulsifiers are primarily used, for example alkali metal or ammonium salts of alkyl, aryl or alkylaryl sulfonates, sulfates, phosphates, phosphonates, or compounds having different anionic end groups, oligo- or polyethylene oxide units possibly being contained between the hydrocarbon radical and the anionic groups. Typical representatives are sodium lauryl sulfate, sodium octyl-phenol glycol ether sulfate, sodium dodecyl benzene sulfonate, sodium lauryl diglycol sulfate and !5 ammonium tri-tert.butyl-phenol penta- and octa-glycol sulfates.

As protective colloids there may be used natural substances such as gum arabic, starch, alginates, or modified natural substances such as methyl, ethyl, hydroxyaikyl, or carboxymethyl cellulose, or synthetic substances, for example polyvinyl alcohol, polyvinyl pyrrolidone, or mixtures of any two or more such substances. Modified cellulose derivatives and synthetic protective colloids are preferred.

To initiate and continue polymerization, oil-soluble and/or preferably water-soluble radical forming agents or 4354 8 - 9 redox systems are used, for example hydrogen peroxide, potassium or ammonium peroxydisulfate, dibenzoyl peroxide, lauryl peroxide, di-tert.butyl peroxide, bisazodiisobutyronitrile, either per se or together with reducing components, for example sodium bisulfite, Rongalite, glucose, ascorbic acid, and other compounds having a reducing action (the word Rongalite is a . Trade Mark).

To prepare the dispsrsion paints of the present invention, the plastics dispersions are blended with a pigment suspension. Pigment suspensions or pigment pastes of this type, which are suitable for making dispersion paints of low pigment content and especially gloss paints, consist, for example, of titanium dioxide uniformly dispersed in water. They contain, in general, protective colloids such as cellulose derivatives, for example hydroxyethyl cellulose, and dispersing agents, for example salts of poly(meth-)acrylic acid or sodium polyphosphate. Other conventional constituents of pigment suspensions are anti-microbic preserving agents, anti-foaming agents, pH stabilizers and fillers. Especially suitable titanium dioxide pigments are the rutile and anatase modifications. For the manufacture of gloss paints the average particle diameter of the pigment should be near the lower limit of the wave length of light, i.e. at about 0.4 to 0.2 micron. For making dull paints of low pigment content, special large surface silicate pigments could be concomittantly used. Dull paints of high binder content yield paint coatings that are easy to clean. The pigment paste may, of course, also contain coloured pigments or the desired shade may be obtained by adding a shading dye-stuff to the dispersion paint containing the white pigment.

The pigment suspension can be prepared in known manner, for example by dispersing the pigment in a dissolver, a ball mill, sand mill or roll mill. For use in gloss paints, the pigment suspension should not contain noticeable amounts d3S18 - 10 of pigment aggregates which would effect the gloss.

Auxiliaries such as plasticizers, cross-linking agents, buffer substances, thickening agents, thixotropic agents, rust preventing agents, alkyd resins, or drying oils may be added to the dispersion or the finished dispersion paint. Suitable plasticizers are not only the solvents mentioned above as film consolidation agents having a temporary action, but also compounds which reduce the filmforming temperature and remain in the polymer for a longer ) period of time, for example dibutyl phthalate.

The following Examples 1 to 12 described the preparation of various plastics dispersions and Example 13, which illustrates the invention, described the preparation and properties of paints incorporating these dispersions as binders. All parts and percentages are by weight unless otherwise stated. The words 'Tylose' and 'Calgon' used in the Examples are registered Trade Marks.

EXAMPLE 1 A dispersion liquor consisting of 603 parts water parts polyvinyl alcohol having a degree of hydrolysis of 88 mol %, and a viscosity of 18 cP at 20°C in a 4% aqueous solution thereof 0.9 part sodium vinylsulfonate 5 6 parts sodium dodecylbenzene sulfonate 0.72 part NaH2PO4 . 2H2O 1.67 parts Na2HPO4 . 12H20 1.5 parts ammonium peroxydisulfate and 60 parts vinyl acetate was heated while stirring in a 2 liter three-necked flask placed in a heating bath and equipped with stirrer, reflux condenser, dropping funnel and thermometer, whereby the polymerization was initiated. When the temperature had reached 70°C, 540 parts vinyl acetate and 18 parts allyl acetoacetate were metered in within 3 hours. Immediately after completion of the monomer addition, heating of the polymerization mixture (70°C) was continued for 2 hours while stirring, and the batch was then slowly cooled.

EXAMPLE 2 (comparison) The procedure described in Example 1 was repeated with the exception that no allyl acetoacetate was added.

EXAMPLE 3 In an apparatus as described in Example 1 a dispersion liquor consisting of 607 parts water parts oleyl polyglyeol ether having about 25 ethylene oxide units 0.2 parts sodium dodecylbenzene sulfonate 12 parts hydroxyethyl cellulose having an average degree of polymerization of about 400 (molecular weight about 100,000) 1.5 parts sodium acetate 2.5 parts ammonium peroxydisulfate and parts of a monomer mixture taken from a mixture of 450 parts vinyl acetate 150 parts vinyl isononanoate and 12 parts allyl acetoacetate was heated to 70°C and the remaining monomer mixture (552 parts) was metered in within a period of 3 hours at this temperature. When the addition was complete 0.5 part ammonium peroxydisulfate in 15 parts water were added and heating was continued for a further 2 hours. The dispersion had a solids content of about 50%. mis - 12 EXAMPLE 4 (comparison) The procedure described in Example 3 was repeated with the exception that no allyl acetoacetate was added.

EXAMPLE 5 In an apparatus as described in Example 1 a dispersion liquor consisting of 618 parts water parts nonylphenol polyglycol ether having about 30 ethylene glycol units 1.5 parts sodium acetate parts hydroxyethyi cellulose having an average degree of polymerization of about 400 and a molecular weight of about 100,000 2.5 parts ammonium peroxydisulfate % (62 parts) of the monomer mixture consisting of 480 parts vinyl acetate, 120 parts di-n-butyl maleate and 18 parts allyl acetoacetate were heated to 70°C and at that temperature there was added, within 3 hours, the remaining monomer mixture.

When the addition was complete 0.5 part ammonium peroxydisulfate in 15 parts water was added and the dispersion was heated for a further 2 hours. The dispersion had a solids content of about 50%. :5 EXAMPLE 6 (comparison) The procedure described in Example 5 was repeated with the exception that no allyl acetoacetate was added.

EXAMPLE 7 In an apparatus as described in Example 1 a dispersion liquor consisting of 636 parts water 18 parts nonylphenol polyglycol ether having about 30 ethylene oxide units 12 parts polyvinyl alcohol having a degree of hydrolysis of 88 mol % and a viscosity of a 4% aqueous solution of 18 cP at 20°C 0.9 part sodium vinyl sulfonate 1.5 parts sodium acetate 2.5 parts ammonium peroxydisulfate 48 parts vinyl acetate, 12 parts vinyl ester of a Versatic acid with 10 carbon atoms, and 1.2 parts allyl acetoacetate was heated to 7Q°C and at that temperature there was added within 3 hours a mixture of 432 parts vinyl acetate, 108 parts Versatic-10-C-acid vinyl ester and 18 parts allylacetoacetate. When the addition was complete 0.5 part ammonium peroxydisulfate in 15 parts water was added and the dispersion was heated for a further 2 hours. The dispersion had a solids content of approximately 50%.

EXAMPLE 8 (comparison) The procedure described in Example 7 was repeated with the exception that no allyl acetoacetate was added.

EXAMPLE 9 A monomer emulsion of 308 parts water parts ammonium tri - tert.butyIphenol polyglycol ether sulfate having approximately 8 ethylene oxide units parts methacrylic acid parts acrylic acid 300 parts 2-ethylhexyl acrylate, ¢3818 300 parts methyl methacrylate and 12 parts allyl acetoacetate was first prepared by rapidly stirring until a stable emulsion was obtained.

In an apparatus as described in Example 1 a mixture of 306 parts water parts ammonium tri - tert.butylphenol polyglycol ether as defined above and. 60 parts of the above monomer emulsion were heated to 81°C and a solution of 0.45 part ammonium peroxydisulfate in 15 parts water was added.

Next, the remaining amount of the monomer emulsion was added in dosed quantities, and the polymerization was continued until it was complete. The total time of addition was 2 hours and the polymerization temperature and the temperature of the after-heating period were in the range of from 81 to 83°C. When the monomer addition was complete 0.15 part ammonium peroxydisulfate in 5 parts water was added, the dispersion was heated for a further 60 minutes, and then it was cooled. The solids content was about 50%.

EXAMPLE 10 (comparison) The procedure described in Example 9 was repeated 5 with the exception that no allyl acetoacetate was added.

EXAMPLE 11 A monomer emulsion having the following composition 310 parts water parts of the sodium salt of lauryl alcohol diglycol ether sulfate 12 parts methacrylic acid parts acrylic acid 300 parts n-butyl acrylate 300 parts styrene and parts allyl acetoacetate was first prepared by rapidly stirring the components until the emulsion was stable.

In an apparatus as described in Example 1 a mixture of 303 parts water parts of the sodium salt of lauryl alcohol diglycol ether sulfate and parts of the above monomer emulsion was heated to 81°C and a solution of 0.45 part ammonium peroxydisulfate in 15 parts water was added. Thereafter, the remaining monomer emulsion was added in dosed quantities, and the polymerization was continued until it was complete. The total period of dosed addition was 2 hours and the polymerization temperature and the after-heating temperature were in the range of from 81° to 83°C. When the monomer addition was complete 0.15 part ammonium peroxydisulfate in 5 parts water were added, the dispersion was heated for a further 60 minutes, and cooled. The solids content was about 50%.

EXAMPLE 12 (comparison) The procedure described in Example 11 was repeated with the exception that no allyl acetoacetate was added.

EXAMPLE 13 Gloss paints were prepared using the dispersions prepared as described above according to the following formulations: (1) 41.0 parts water .6 parts of a 3% aqueous solution of Tylose H 20 0.4 parts Calgon N (solid) 3.0 parts dispersing agent PA 30 1.0 part ammonia of 25¾ strength 2.0 parts of preserving agent 3.0 parts of anti-foaming agent 175 parts of titanium dioxide having a particle size of from 0.2 to 0.4 micron .0 parts 1,2-propylene-glycol were dispersed and then (2) 710 parts of one of the above dispersions (with a solids contents of 50%) to which had been added 2.0 parts ammonia of 25% strength if the pH did not exceed approximately 7, were added.

Subsequently a mixture of (3) parts butyl diglycol acetate and ' 27.0 parts 1,2-propylene-glycol was slowly added while stirring.

The liquid or soluble components indicated in (1), with the exception of the 1,2-propyleneglycol, were intro25 duced in the above sequence into a vessel provided with a stirrer, and the pigment was then dispersed in this mixture by means of a dissolver. Subsequently 1,2-propyleneglycol was added. In order to ensure identical conditions for mixing with the different dispersions to be tested, for example iO in view of pigment dispersion, a large amount of this pigment paste was manufactured.

For the manufacture of the individual paints a corresponding proportion of the pigment pastes was mixed according to the above formulation, while slowly stirring, with the dispersions approximately one day old, whereupon the organic - 17 liquid mixture (3} was added. After complete mixing, the paints were passed through a sieve.

These gloss paints were allowed to stand for one day and then spread onto glass plates and steel sheets onto which a pigmented glossy air - drying alkyd resin enamel had been sprayed and which had been aged after drying for 24 hours at 100°C. A film applicator was used having a slit diameter of 200 microns. After a drying period of 24 hours the wet adhesion of the gloss paints was tested according to the two following methods: (1) Abrasion test; The glass plates with the dried coating of dispersion paint were inserted in a mechanical abrasion device as described, for example, in German Offenlegungsschrift No, 2,262,956 and similar to the Gardner Washability and Abrasion Machine, but having a stroke length of approximately 1.20 m in a manner such that the applied films of dispersion paint were in a vertical position with respect to the direction of movement of the brush. Due to the long moving dist20 ance about 15 paints could be simultaneously tested in one run. A brush with hog's bristles was used which, at the beginning of the test, had been wetted with distilled water. During the test the area on which the brush moved was also wetted with distilled water so that the brushed areas were per25 manently covered with a water film. With a poor wet adhesion the dispersion paint was brushed off the substrate after a few strokes of the brush and torn at the boundary between wetted and dry film. The better the wet adhesion, the greater the number of strokes of the brush until the film is shifted aside. The dispersion paint has an optimum wet adhesion when in the wetted area the film is not damaged after 3,000 strokes of the brush, one stroke including a backward and forward movement. - 18 (2) Condensation test: A rectangular thermostat chamber was used one half of which was filled with water at 50°C and in the gas space of which above the water level was mounted a fan. The upper opening was covered with the steel sheets with the coated surface facing downwards so that the thermostat chamber was closed. The thermostat was kept in a room maintained at 23°C. Owing to the temperature difference steam condensed on the lower surface of the sheets and acted on the coats of paint. After 15 minutes the sheets were removed and the coatings evaluated.

With an unsatisfactory wet adhesion, blisters form between the film of dispersion paint and the alkyd resin lacquer and the film can be easily shifted aside, for j example, with the finger-tip. A film having a good wet adhesion is still free of blisters after a period of 4 hours and cannot be shifted.

The test results are listed in the following Table, Paint incorporating dispersion of Example No. Abrasion test; Number of strokes of brush Stability in condensation test 1 >3000 4 hrs. 2* 30 10 min. 3 >3000 4 hrs. 4* 250 10 min. 5 >3000 4 hrs. 6* 120 15 min. 7 >3000 4 hrs. 8* 50 15 min. 9 >3000 4 hrs. 10* 70 15 min. 11 >3000 4 hrs. * 12 110 15 min.

* Comparative Examples

Claims (8)

1. An aqueous dispersion paint comprising an organic liquid, from 7 to 30% by volume of a pigment, and as binder or part of a binder system, a copolymer containing from 0.5 to 10% by weight, relative to all monomer units in the binder or binder system, of units derived from an olefinically unsaturated acetoacetic acid ester, and units derived from at least one other olefinically unsaturated monomer.

2. A paint as claimed in claim 1, wherein the acetoacetic acid ester is vinyl acetoacetate, allyl acetoacetate or a diester of the formula I II II II R— CH=C—C 0—A C —CH 2 C—CH 3 in which R is H or CH^; A is or n is an integer from 1 to 4 and m is an integer of from 1 to 3.

3. A paint as claimed in claim 1 or claim 2, wherein the copolymer contains from 1 to 5% by weight, relative to all monomer units in the binder or binder systems, of units derived from an olefinically unsaturated acetoacetic acid ester.

4. A paint as claimed in any one of claims 1 to 3, which comprises from 10 to 20% by volume of a pigment.

5. A paint as claimed in any one of claims 1 to 4, wherein the binder is a mixture of different polymer dispersions of which at least one contains suoh an amount of acetoacetic acid ester units in the polymer portion that the 20 quantity of acetoacetic acid ester, relative to the weight of all monomers present in the mixture, is from 0.5 to 10% by weight.

6. A paint as claimed in any one of claims 1 to 5, wherein the copolymer containing units derived from an ace toacetic acid ester is a copolymer produced from a combination of monomers substantially as set forth hereinbefore.

7. A paint as claimed in any one of claims 1 to 5, containing as binder a copolymer containing units derived from an acetoacetic acid ester, the copolymer being substantially as described in any one of Examples 1, 3, 5, 7, 9 and 11 herein.

8. A paint as claimed in claim 1, substantially as described in Example 13 herein and containing as binder a copolymer dispersion as described in any one of Examples 1 3, 5, 7, 9 and 11 herein.