GB1598934A - Method of coating with air-curable ester-amide polymers - Google Patents

Description

(54) METHOD OF COATING WITH AIR-CURABLE ESTER-AMIDE POLYMERS (71) We, ROHM AND HAAS COMPANY, a Corporation organized under the laws of the State of Delaware, United States of America, of Independence Mall West, Philadelphia, Pennsylvania 19105, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- This invention is concerned with a method of coating using polymer compositions and with certain polymers. The compositions comprise a watersoluble salt of a polymer containing pendant air-curable groups preferably derived from an unsaturated drying oil fatty acid hydroxyamide and carboxy groups, carboxy ester groups and optionally the residues of other unsaturated addition polymerizable monomers. The polymers have certain critical properties, such as the carboxy unit content, glass transition temperature and molecular weight.

Air-curable ester-amide polymers are disclosed and claimed in UK Application No. 19846/80, Serial No. 1,598,935.

In the past, similar polymers have been known for coatings and for other uses, such as putty-like caulking compositions. The caulking compositions are disclosed in U.S. Patent No. 3,759,915 whereas the coating compositions are disclosed in U.S.

Patent No. 3,590,016. This invention is an improvement upon U.S. Patent No.

3,590,016. In that patent, as in the present application. the polymers contain an acrylic backbone having pendant carboxy units, post-reacted in the preferred embodiment with N-hydroxyalkylamides. In the patent, the acid moiety of the hydroxyamide can be saturated or unsaturated, and the polymers disclosed in the examples are exceptionally brittle, having a high glass transition temperature (Tg).

The polymer of the patent can be water-soluble or water-insoluble. Salts of the polymer containing carboxyl groups, disclosed in the patents can be neutralized with ammonia, certain amines, or other bases, including ones unsuitable for use in the present invention, when a metal drier salt is used. Problems encountered with these prior art polymers include the formation of gel, poor gloss when dried under high humidity conditions, slow development of block resistance, and unstable dispersions.

We have now found a water-soluble air-curing polymeric material in which certain parameters and features of the polymer are critical for such utilization. For example, the finished coating must have a Tg of 65"C. or less, preferably below 60or. The calculated Tg of the prepolymer or backbone polymer, before esterification by the hydroxyamide, should preferably be below 500 C., although it can be as high as 85 C., if large quantities of the amide units are present.

According to the invention there is provided a method of coating which comprises applying a polymer composition to a substrate and drying and curing the composition, or allowing it to dry and cure, in the presence of air, said composition comprising: (A) an aqueous alkaline solution of an addition polymer solubilized in the solution by ammonia or a volatile amine, the polymer containing: (i) from 5 to 60, preferably 10 to 40, for example 10 to 30, parts by weight of units of the formula:

(ii) from 20 to 90 parts by weight of units of the formula:

(iii) from 5 to 20, preferably 8 to 15, parts by weight of units of one or more unsaturated carboxylic acids, as hereinafter defined, preferred units having the formula:

ana (iv) the balance, if any, to make 100 parts by weight of units of one or more other ethylenically unsaturated addition polymerizable monomers; wherein R1 is H, (C1-C5)-alkyl, halogen, -CN, -CH2COOR, -COOR or -CH2COOH, where R is (C1C8)-alkyl; R is (CR27)n, where R7 is H or -CH3 and n is 1 or 2, preferably 2; R is H or (C1-C8)-alkyl, preferably H, -CH3 or -CH2CH3, R4 is an unsaturated air-curable aliphatic hydrocarbon radical; R5 is H, -COOH, -CONH2 or COOR, where R is (C1-C8)-alkyl: R6 is an aliphatic or cycloaliphatic radical containing from I to 20 carbon atoms: the amount of units (iii) being sufficient to provide the polymer with a carboxy content of from 0.5 to 3 meq/g., preferably from 0.6 to 2.5 meq/g., and the amount of carboxy groups in the form of salt groups with said amine or ammonia being sufficient to confer water solubility on the polymer units (ii) being derived from monomer whose homopolymer has a T of from -80"C. to 120"C., the polymer having a viscosity average molecular weight of from 10,000 to 100,000 preferably from 20,000 to 80,000 and a cured film of the polymer having a Tq of from -20"C. to 650C. and a Tukon hardness of from 0.2 to 10 and,~optionally, (B) a metal compound drier in an amount of up to 0.5% by weight, on a metal basis, of the total weight of the polymer in the composition.

The polymers used in this invention, containing units (i) above, may be prepared by the esterification of a backbone or parent polymer with an hydroxyamide.

The parent polymer contains units of the formula:

where X represents units (iv), the other ethylenically unsaturated monomer(s), when present, and R8 is H and R6 and R', R5 and R6 are as previously defined.

The hydroxyamide, a fatty acid amide, has the formula:

where R2, R3 and R4 are as previously defined.

The preparation of the fatty acid hydroxyamide is carried out by well known procedures, as is the esterification of the carboxyl groups on the polymeric backbone by the hydroxyamide. Exemplary of publications describing these are The Journal of the American Oil Chemists' Society, Volume 46, pages 355-364, published in 1969, which discloses the use of diethanolamine to produce fatty acid hydroxyamide rather than the monoethanolamine which is preferred in the present invention, German Patent No. 1,940,471 and Belgian Patent No. 757,271 and corresponding U.S. Patent No. 3,590,016 noted above, the latter two relating to hard coatings such as paints. The U.S. and Belgian Patents relate to the same type of polymer generally, although the products taught therein have several defects making them unsuitable for many uses. For example, all of the backbone polymers disclosed are brittle or hard polymers. Thus, it appears that the softest polymer backbone, of the patent examples would be of styrene and/or methyl methacrylate that would have a glass transition temperature (T") of 100"C. or above.

The fatty acid amide and thus R4 in formula I is preferably derived from one or more drying oils, such as linseed, tung, tall, saf-flower, conjugated saf-flower, isano, soya, dehydrated castor, oiticica, menhaden, and similar oils, as well as those of synthetic origin, with a carbon chain preferably of about 20 carbon atoms or less and having unsaturation therein which can be caused to air cure in a manner analogous to linseed oil. The preferred oils are those in which the major component contains two or more olefinically unsaturated groups, which may be either conjugated or alternating, including in addition to oiticica and dehydrated castor oils, those which contain predominantly linoleic and/or linolenic acids.

In a preferred embodiment, R4 is derived from a blend of drying oils which contains 5W90 Nn by weight of one or more of dehydrated castor, saf-flower, conjugated saf-flower or soyabean oils with 10--50yb by weight of tung oil.

Thus Formula IV represents that portion of the addition polymerized polymer backbone having free carboxyl groups as well as carboxyl groups which have been esterified by the various alcohols conventionally used. The optional portion -X- is derived from any of the well-known unsaturated addition polymerizable vinyl monomers as defined below.

It is to be understood that when R' and/or R5 contain free carboxy groups (-COO H), the hydroxyamide will react therewith to give pendant ester groups equivalent to the structure of Formula I.

Examples of R' and R5 are: Acid for R' R5 Carboxyl Source H H Acrylic CH3 H Methacrylic H COOH Maleic, fumaric H CONH2 Maleamic Cl COOH Chloromaleic CH2COOCH3 H Methyl acid itaconate CH2COOH H Itaconic CH2COOH COOH Aconitic H COOCH3 Half ester of maleic The present polymer, prior to esterification with the hydroxyamide, is a waterinsoluble vinyl polymer containing the requisite proportion of carboxyl (COOH) groups as described herein. The backbone polymersperse are well known in the art and form no part of the present invention.

The proportions of monomers in the backbone are such that there is at least 5% and no more than 20%, preferably less than 15% of unsaturated carboxylic acid, by weight, as units of Formula IV wherein R6 is -H. An especially preferred range is from 8% to 15%, and the optimum is considered to be in the range of 10? to 120/.

It is most desirable to have a substantial proportion of free carboxyl groups for proper adhesion and, for maximum long term flexibility, a minimum of the drying oil functionality.

The preferred parent polymers are vinyl addition polymers, including as an essential component the , -unsaturated carboxylic acid, preferably acrylic acid or methacrylic acid. Other useful copolymerizable acids are named in US Patent Nos.

3,098,760 and 3,261,796 addttttional examples being given below.

By "unsaturated carboxylic acid" in units (iii) is meant a simple monocarboxylic acid, a polycarboxylic acid, or a partial ester or half amide of ,- unsaturated polycarboxylic acids, and salts thereof with a volatile base such as ammonia, or with a volatile amine, which form water-soluble salts with the compolymerized acid. Examples of such amines include dimethyl-amine, triethylamine, diethanolamine, triethanolamine, morpholine, N-methyl morpholine and picoline.

When a drier is present and the acid is in salt form with an amine it is preferred that the amine is a monoamine and not a polyamine, since the latter may interact with the metal of the siccative. Examples of copolymerizable ethylenically unsaturated monocarboxylic or polycarboxylic acids are sorbic, acryloxyacetic, acryloxypropionic, cinnamic, vinyl furoic, a-chlorosorbic, methacryloxypropionic, methacryloxyacetic, p-vinylbenzoic, acrylic, methacrylic, maleic, fumaric, aconitic, atropic, crotonic, and itaconic acids, or mixtures thereof. Itaconic acid and the a,p-unsaturated monocarboxylic acids, particularly methacrylic acid and acrylic acid, are preferred. Other copolymerizable acid monomers include the alkyl half esters or partial esters of unsaturated polycarboxylic acids such as of itaconic acid, maleic acid, and fumaric acid, or the partial amides thereof. Preferred half esters are the lower alkyl (C1 to C6) esters such as methyl acid itaconate, butyl acid itaconate, methyl acid fumarate, butyl acid fumarate, methyl acid maleate and butyl acid maleate. Such partial esters, as well as partial amides, are considered to be "s, -unsaturated monocarboxylic acids," and the term as used herein includes such esters and amides.

The term "vinyl monomer" as used herein means a monomer comprising at least one of the following groups: Vinylidene CH2=C < vinyl CH2-CH-, and vinylene -CH=CH-, whether homopolymerizable or not, giving units corresponding to X, when present.

Examples include the a, -ethylenically unsaturated monocarboxylic acid amides, cr, -ethylenically unsaturated aldehydes, a"B-ethylenically unsaturated dicarboxylic acid amides, a,p-ethylenically unsaturated nitriles, hydrocarbons such as a-olefins, conjugated diolefins, vinylaryl compounds, vinyl alkyl ethers, vinyl halides, vinylidene halides, vinyl sulfides, vinyl acyloxy compounds (esters of saturated carboxylic acids and ethylenically unsaturated alkanols), vinyl amines and salts thereof, vinyl ureido monomers, vinyl compounds having heterocyclic nitrogencontaining (HN < ) groups, and halogen, hydroxyalkyl, or aminoalkyl substituted derivatives, thereof, whether homopolymers or copolymers.

For examples of well-known vinyl polymers which may be used in the invention, and methods of preparing the same, see Polymer Processes", Schildknecht, Interscience, N.Y. (1956), pp. 111-174. Mixtures of different polymers are useful.

Specific examples of suitable monomers which may be copolymerized to obtain the water-insoluble parent polymers for use according to the invention in addition to the unsaturated acid monomers and esters thereof with alkanols having one to 20 carbon atoms, such as methanol, ethanol, butanol and pentadecanol are acrolein, methacrolein, ethylene, propylene, isobutene, butadiene, isoprene, chloroprene, styrene, vinyl toluene, vinyl methyl ether, vinyl isobutyl ether, vinyl chloride, vinyl bromide, vinylidene chloride, vinyl sulfide, vinyl acetate, vinyl propionate, the vinyl pyridines; primary amino compounds such as p-aminoethyl vinyl ether, aminopentyl vinyl ether; secondary amino-containing compounds such as t-butylaminoethyl methacrylate; tertiary amino containing compounds such as dimethylaminoethyl methacrylate, and the allied amine salts such as the chloride or hydroxide, and ureido monomers such as are disclosed in U.S. Patent No. 3,356,627 to Scott. Copolymers and graft, block, or segmented polymers are included.

Conventional~methods of obtaining the backbone polymers are utilized.

Another of the essential monomers, in addition to the acid monomer, usually utilized in a substantial proportion to prepare the parent polymer, is a resiliency imparting or soft monomer which may be represented by the following formula:

wherein R is H or alkyl having I to 4 carbon atoms and R" is the straight chain or branched chain radical of a primary or secondary alkanol, alkoxyalkanol or alkylthiaalkanol, and having up to about 14 carbon atoms, examples being ethyl, propyl, n-butyl, 2-ethylhexyl, heptyl, hexyl, octyl, propyl, 2-mefhylbutyl, 1 methylbutyl, butoxybutyl, 2-methylpentyl, methoxymethyl, ethoxymethyl, cyclohexyl, n-hexyl, isobutyl, ethylthiaethyl, methylthiaethyl, ethylthiapropyl, noctyl, 6-methynonyl, decyl, dodecyl, and the like, said radicals R", when alkyl, having from two to about 14 carbon atoms, preferably from three to 12 carbon atoms, when R is H or methyl. When R is alkyl and R" is alkyl, R" should have from about 6 to about 14 carbon atoms and when R is H and R" is alkyl, R11 should have from about two to about 12 carbon atoms, in order to qualify as a soft monomer.

Other ethylenically unsaturated copolymerizable vinyl monomers, the homopolymers of which have a much higher Tg, are preferably used in combinations with the above mentioned soft monomers, provided they do not adversely affect the desired properties of the product (e.g., unduly raise the overall Tg). These "hard" monomers may be represented by the formula:

wherein R is as above, R22 is preferably alkyl and is methyl when R is H, and is alkyl of from one to about five carbon atoms or alkyl of from about 15 to about 20 carbon atoms when R is methyl. Examples of these hard ester monomers and other hard monomers include: methyl acrylate, acrylamide, acrylonitrile, isobutyl methacrylate, vinyl acetate, tetradecyl acrylate, pentadecyl, acrylate, methyl methacrylate, ethyl methacrylate, t-butyl acrylate, butyl methacrylate, styrene, pentadecyl methacrylate, vinyl toluene, methacrylamide, and Nmethylolacrylamide.

As is known, for a given number of carbon atoms in the alcohol moiety, the extent and type of branching markedly influence the Tg, the straight chain products giving the lower Tg.

As is apparent, an important property of the backbone polymer is the Tg thereof, and consequently the selection of monomers and proportions thereof depends upon their influence on the Tg. "Tg" is a conventional criterion of polymer hardness and is described by Flory, "Principles of Polymer Chemistry", pp. 56 and 57 (1953), Cornel University Press. See also "Polymer Handbook", Brandrup and Immergut, Sec. III, pp. 61-63, Interscience (1966). While actual measurement of the Tg can be used, it may be calculated as described by Fox, Bull.

Am. Physics Soc. 1, 3, p. 123(1956), or by the use of"Rohm and Hass Acrylic Glass Temperature Analyzer" Publication No. CM-24 L/cb, Rohm and Haas Company, Philadelphia, Pa., 19105. While the actual Tg of the prepolymers is much lower than the calculated Tg because of the low molecular weights. the calculated Tg is a relevant indicia of the relative Tgs of different polymers. Examples of the Tg of high molecular weight ( < 1,000,000) homopolymers and the inherent Tg thereof which permits such calculations are as follows: Homopolymer of Tg n-octyl acrylate -80"C. n-decyl methacrylate -60 C.

2-ethylhexyl acrylate -70"C. n-butyl acrylate -56 C. octyl methacrylate 200 C. n-tetradecyl methacrylate -9"C. methyl acrylate 9"C. n-tetradecyl acrylate 20"C. t-butyl acrylate 43"C. methyl methacrylate 105"C. acrylic acid 106"C.

These or other monomers are blended to give the desired Tg of the copolymer.

The parent polymer is desirably obtained by solution polymerization of one or more of the ethylenically unsaturated acids with other unsaturated monomers including, among the more preferred vinyl monomers, the esters of acrylic acid and/or methacrylic acid with benzyl alcohol, phenol, or a saturated monohydric aliphatic alcohol, especially an alkanol having one to 18 carbon atoms, such as cyclopentanol, cyclohexanol, methanol, ethanol, n-propanol, isopropanol, nbutanol, methoxyethanol, ethoxyethanol, methoxyethoxyethanol, ethoxyethoxyethanol, isobutanol, sec-butanol, tert-butanol, any of the pentanols, hexanols, octanols, decanols, dodecanols, hexadecanols, and octadecanols, bearing in mind the required Tg and acid monomer. Preferred vinyl monomers, in addition to the acid, include one or more of an ester of an cr,a-unsatuated carboxylic acid, or, when those optional vinyl monomers are used, an unsaturated nitrile, a vinyl halide, a vinylidene halide, a vinyl aromatic, a vinyl alcohol ester, or an unsaturated hydrocarbon, especially acrylonitrile, methacrylonitrile, vinyl acetate, styrene, vinyl toluene (o, m, orp), vinyl chloride or vinylidene chloride, to give the units X in the foregoing formula. Blends of copolymers may be used.

The solvents used in the polymerization may be such organic solvents and mixtures thereof such as benzene, toluene, xylene, solvent naphthas of aliphatic, aromatic, or naphthenic type such as mineral spirits, ethers, esters, acetone, dioxane, etc. Preferred solvents are the monoalkyl (C1-C4) ethers of ethylene glycol, diethylene glycol, or propylene glycol, sold under the trademarks "Carbitol", "Cellosolve", and "Propasol". Of course, other modes of polymerization can be used. The amount of solvent in the polymer is from 00; to 80% based on polymer solids, preferably, from 10% to 65%.

Any of the conventional driers or siccatives, such as the linoleates, naphthenates, and resinates of cobalt, zirconium, manganese, lead, cerium. chromium, iron, nickel, uranium, and zinc are suitable. Inorganic acid salts can also be used.

The amount of drier, if used, based on the weight of the hydroxyamide of Formula V can be as low as 0.01% to as high as 3% or more. Good results are often obtained with combinations of driers, such as zinc naphthenate arid cobalt naphthenate in quite small amounts, for example, from .01% to 0.5% of the zinc naphthenate together with 0.01% to 0.1% cobalt naphthenate are particularly useful. Co++ as cobaltous acetate is also useful, alone or with compounds providing Mn++, Zn++, Zr++, or Pb++.

A preferred polymer for use in the method of the invention contains: (a) 5-30, preferably 1030, parts by weight of units of formula I; (b) 1050 parts by weight of one or more esters of acrylic acid and/or methacrylic acid, which when homopolymerized gives a polymer having a Tg of from 0 C. to 800 C., preferably below -100C.; (c) 2070 parts by weight of one or more of esters of acrylic acid and/or methacrylic acid, vinyl aromatic hydrocarbons and unsaturated nitriles which when homopolymerized gives a polymer having a Tg of from 20"C. to 1200C., preferably from 500C. to 1200C.; (d) 5-15, preferably 8-15, parts of an ethylenically unsaturated carboxylic acid and, optionally, (e) up to 20 parts of one or more different ethylenically unsaturated monomers which confers. hydrophilicity to the polymer and enhance its solubility in aqueous liquids: the total of (a), (b), (c), (d) and (e), when present, being 100 parts by weight.

Preferably in this polymer the quantity of ethylenically unsaturated acid units is such as to provide from 0.6 to 2.5 meq/g. of the polymer.

Still more preferably, the polymer is one wherein: (b) is one or more of ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, secbutyl acrylate, isobutyl acrylate, and isopropyl acrylate, (c) is one or more of methyl methacrylate, styrene, ethyl methacrylate, acrylonitrile, butyl methacrylate, isobutyl methacrylate, and vinyl toluene, and (d) is one or more of acrylic acid, methacrylic acid, maleic acid, and itaconic acid, (e) when present, is one or more of the hydrophilic monomers, hydroxyethyl or hydroxypropyl (meth)acrylate.

The preferred viscosity average molecular weight, is from 20,000 to 80,000, more preferably from 30,000 to 50,000.

In a preferred polymer, in Formula I, n is 2, R3 is -H, -CH3, or -CH2CH3, and K4 is the resldue ot one or more ot the drying oil acids selected from tung oil acids, linseed oil acids, dehydrated castor oil acids, safflower oil acids, conjugated safflower oil acids, soybean oil acids and oiticica oil acids. An especially preferred combination of unsaturated drying oil acids is 5090 /O of the acids of dehydrated castor oil, safflower oil, conjugated safflower oil or soybean oil mixed with 1050% by weight of the acids from tung oil.

It is possible to utilize a single acrylate or methacrylate ester, there being no necessity to use a combination of the suitable hardness and glass transition temperatures can be obtained otherwise. An example of a polymer of this type is one which contains polymerized units consisting essentially of: (a) 5--30 parts by weight of units of Formula I and, (b) 45-90 parts by weight of butyl methacrylate, (d) 5-15 parts by weight of an ethylenically unsaturated carboxylic acid, the quantity of ethylenically unsaturated acid being between from 0.6 to 2.5 meq/g. of polymer, (e) optionally, up to 20 parts by weight of a different ethylenically unsaturated monomer which confers hydrophilicity to the polymer and enhances its solubility in aqueous liquids, the total of (a), (b), (d) and (e) being 100 parts by weight.

The substrates with which the invention is concerned are of all types, including siliceous substrates such as glass sheets, fiberglass textiles, asbestos sheets, asbestos cement products, concrete, stone, stucco, slate, sandstone, granite, ceramics, and porcelain, also fiber reinforced plastic articles such as canoes, boat hulls, or other formed articles made out of fiberglass reinforced polyesters or other plastic materials; metals such as aluminum, steel, iron, brass; wood and other structural materials; metal oxide layers such as those of aluminum oxide and iron oxide; leather: textiles of cellulose such as of cotton, linen, silk, wool, rayon, cellulose esters such as cellulose acetate, nylons, polyesters such as polyethylene glycol terephthalate, acrylonitrile polymers, vinylidene chloride polymers and other vinyl or acrylic ester polymers; films, pellicles, sheets and other shaped articles of plastic systems such as of cellulose ethers or esters including hydroxyethyl cellulose, methyl cellulose, cellulose actate, cellulose acetate butyrate, polyesters such as polyethylene glycol terephthalate, nylons, vinyl chloride or vinylidene chloride polymers and copolymers, methyl methacrylate polymers and copolymers, aminoplast or phenoplast resins, organopolysiloxane resins, or rubber.

Preferably the coatings have a thickness of from 0.1 to 10 mls when dry.

The products of the present invention are particularly valuable in that they usually can be used directly on any of the substrates without the need of a priming coat.

The polymers are particularly useful as additives for latexes as illustrated by Example 3. Suitable latexes are aqueous addition polymer dispersions, generally obtained most conveniently by direct emulsion polymerization. The most important of these dispersions used in making water-based paints are polymers including homopolymers and copolymers of: (1) vinyl esters of an aliphatic acid having 1 to 18 carbon atoms, especially vinyl acetate; (2) acrylic acid esters and methacrylic acid esters of an alcohol having I to 18 carbon atoms, especially methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate and butyl methacrylate; and (3) mono- and diethylenically unsaturated hydrocarbons, such as ethylene, isobutylene, styrene, and aliphatic dienes such as butadiene, isoprene, and chloroprene.

Poly(vinyl acetate) and copolymers of vinyl acetate with one or more of the following monomers; vinyl chloride, vinylidene chloride, styrene, vinyltoluene, acrylonitrile methacrylonitrile, one or two of the acrylic and methacrylic acid esters mentioned above are well known as the film-forming component of aqueous base paints. Similarly copolymers of one or more of the acrylic or methacrylic acid esters mentioned above with one or more of the following monomers: vinyl acetate, vinyl chloride, vinylidene chloride, styrene, vinyltoluene, acrylonitrile and methacrylonitrile are also more or less conventionally employed in aqueous base paints. Homopolymers of ethylene, isobutylene and styrene, and copolymers of one or more of these hydrocarbons with one or more esters, nitriles or amides of acrylic acid or of methacrylic acid or with vinyl esters, such as vinyl acetate and vinyl chloride, or with vinylidene chloride are also used. The diene polymers are generally used in aqueous base paints in the form of copolymers with one or more monomers following styrene, vinyltoluene, acrylonitrile, methacrylonitrile, and the above mentioned esters of acrylic acid or methacrylic acid. It is also quite common to include a small amount, such as 1/2 to 5% or more of an acid monomer in the monomer mixture used for making the copolymers of all three general types mentioned above by emulsion polymerization. Acids used include acrylic, methacrylic, itaconic, aconitic, citraconic, crotonic, maleic, fumaric, the dimer of methacrylic acid, and so on.

These aqueous dispersions may be made using one or more emulsifiers of anionic, cationic, or non-ionic type. Mixtures of two or more emulsifiers regardless of type may be used, except that it is generally undesirable to mix a cationic with an anionic type in any appreciable amounts since they tend to neutralize each other.

Furthermore, many cationic types of emulsifier are incompatible with the polymers used in the invention. The amount of emulsifier may range from about 0.1 to 5 O by 50-90% latex polymer, solids basis. They are insoluble in aqueous media at a pH of 3-11.

Some preferred embodiments of the invention will now be more particularly described in and by the following examples in which all parts and percentages are by weight and the temperature in C., unless otherwise specifically noted.

In the examples the abbreviations for monomers have the following meanings: BA-butyl acrylate HEMA-2-hydroxyethyl methacrylate MMA-methyl methacrylate MAA-methacrylic acid AA-acrylic acid BMA-butyl methacrylate S-styrene EA-ethyl acrylate AN-acrylonitrile IB MA-isobutylmethacrylate MHELAE-linseed oil acids amide ester MHESAE-soybean oil acid amide ester MHESAFAE-safflower oil acid amide ester MHEDCAE-dehydrated castor oil acid amide ester MHETAE-tung oil acid amide ester MHESTAE-stearic acid amide esters non-drying acid amide ester HELAE-N-hydro;;yethyl linseed oil acid amide ester HESAFE-N-hydroxyethyl safflower oil acid amide ester unit.

In the following Table, the prepolymers having a solids content of 8590% were made by solution polymerization in butyl Cellosolve, which was followed by post-polymerization esterification with the drying oil N - methyl - N - (ss hydroxyethyl)amide of a portion of the copolymerized unsaturated acid. The synthesis details are set forth in Table I, with a typical procedure being set forth following Table II.

TABLE I Polymerization % Transfer Temperature Molecular No. BA/MMA/MHELAE/AA Initiator Agent4 ( C) Weight5 A 40/30/20/10 1.0 0.25 ll00C. 80,000 B 40/30/20/10 1.0 0.5 110 C. 42,300 C 40/30/20/10 1.0 0.5 150 C. 34,000 D 40/30/20/10 3.0 1.0 150 C. 19,000 E 20/50/20/10 1.0 0.25 110 C. 75,700 F 30/40/20/10 1.0 0.5 110 C. 58,000 G 30/40/206/10 1.0 0.5 110 C. 56,000 H 20/42/30/8 1.0 0.5 150 C. 22,500 I 10/42/40/8 1.0 0.5 150 C. 32,000 MHELAE-Ester formed from the reaction of N - methyl - N - (ss hydroxyethyl) linseed amide (MHELA) and copolymer acid.

2Percent initiator based on prepolymer weight.

3Lupersol PMS-t-butyl peroctoate. ("Lupersol" is a Registered Trade Mark).

4Mercaptoethanol.

5Viscosity average; Mv 6Tung oil analogue (MHETAE) At the higher drying oil levels, the molecular weight of the uncured polymer increases somewhat.

The polymers having a viscosity average molecular weight of about 40,000 require significantly less pendant drying oil functionality, approximately 20% for good curing characteristics, than do polymers of about 20,000 Mv, which show efficient curing at about 40% pendant drying oil functionality.

Cure rate is a function of drying oil type. Cure efficiency is also a function of drying oil type and quantity. Some polymers containing styrene or acrylonitrile are shown to cure at a slightly reduced rate; analogous polymers containing hydroxyethyl methacrylate (HEMA) exhibit an enhanced cure rate.

The viscosity average molecular weights as determined herein are in general agreement with gel permeation chromatography (gpc) molecular weight determlnations. In most cases, gpc. molecular weights were determined on methylated prepolymers, methylated to reduce the copolymer acid for more reliable measurements. "Prepolymers" are the polymers before esterification with the drying oil hydroxyethyl amides, also called backbone or parent polymers. The molecular weights listed were calculated from the prepolymer molecular weights plus the weight of the drying oil amide. In one example (F) the gpc molecular weight was determined directly on the methylated final polymer. The good agreement between E and F indicates that few crosslinks are formed between drying oil chains during the post-polymerization esterification.

TABLE II Comparison of Molecular Weight Data by Two Different Techniques X-103 No. IiA/MMA/MHELAE'/AA Mv2 Mw3 Mn3 Mw/Mn A 40/30/20/10 80 88 22 4 B " 42 60 19 3 C " 34 24 5 5 D " 19 13 4 3 E 20/42/30/8 22 15 4 3 F 154 44 3 'MHELAE--Ester formed from the reaction of N - methyl - N - (p - hydroxyethyl) linseed amide (MHELA) and copolymer acid.

2Viscosity average molecular weight.

3gpc molecular weights determined on methylated prepolymers from which the final molecular weights were calculated.

4gpc molecular weights determined on methylated final polymer (prepolymer+MHELA) directly.

The solution viscosities of water-soluble copolymers can be markedly reduced by the addition of a cosolvent. It has been concluded that (a) the solubility parameter and hydrogen bonding class of a cosolvent have no relationship to the efficiency of the cosolvent in reducing solution viscosity, and (b) among the better cosolvents (acetonitrile, isopropanol, isobutanol acetone, methyl ethyl ketone) all are approximately equally effective in reducing solution viscosity. Other useful cosolvents include butyl "Cellosolve", butyl "Carbitol", "Propasol" B, "Propasol" P, and diacetone alcohol.

It is important to cool the batch promptly after the esterification is completed, otherwise gelation may occur. Temperature reductions can be achieved by refluxing a water-xylene azeotrope during esterification and by subsequent removal of the azeotrope by the use of a vacuum without applying additional heat.

Esterification temperature and time are also important. When a temperature of 165"C is used, esterification must be completed in a much shorter time, for example 10 minutes, in order to have a reasonable gel-free time as compared to esterification at 1450C., where substantial gel-free time is obtained even when the esterification is carried out over a period of 45 minutes. Other factors contributing to gel-free time are copolymerized acid content, in that a lower content of acid gives a longer gel-free time, and the total solids, in that the lower solids content products have a longer gel-free time. Another factor is the nature of the drying oil acid. The order of susceptibility to gelation is as follows: dehydrated castor > tung > lineed=safflowerZsoyZstearic. Additives which will quench the gelation effect are sometimes useful. These additives include carboxylic acids and aniline. Examples of the acids are: monochloroacetic acid and benzoic acid.

The following gives a sample calculation for determining the relative weight ratios of units in the final polymer.

Sample Calculation: This illustrates the preparation of 3()BA/42MMAi2utvIrIELAE/8AA polymer by reacting the carboxy-containing parent polymer with N-methyl-N-hydroxyethyl linseed oil acid amide.

337 Average Molecuar Average + 72 (AA) Weight=337 molecular - 18 (H3O) weight 391 A prepolymer of composition 35.86BA/50.19MMA/13.95AA (calculated T=8 C.) is reacted with 20.59%, on the basis of prepolymer weight, of N-methyl N-hydroxyethyl linseed oil acid amide (MHELA). Thus, 100 g. of prepolymer is reacted with 20.59 g. of N-methyl-N-hydroxyethyl linseed oil amide.

20.59 .0611 moles amide.

337 72x.0611=4.40 gms. AA in .0611 moles.

18x.0611=1.10 gms. H2O in .0611 moles.

Wt. of MHELAE units=20.59+4.40-1.l0=23.89 g.

Final Composition gms BA 35.86 30 MMA 50.19 42 AA 13.95-4.40= 9.55 8 MHELAE 23.89 20 119.49 The polymer compositions herein were calculated in a similar manner.

The cured films of polymers in Examples I to 15 have a Tg of from -20"C. to 650C. and Tukon hardness of from 0.2 to 10.

Example 1 Preparation of 40BA/30MMA/20MHELAE (linseed oil)/lOAA having an Mv of about 40,000) A monomer mixture of the following materials was prepared: Parts Butyl acrylate 326.0 Methyl methacrylate 244.6 Acrylic acid 110.4 Mercaptoethanol 3.4 An initiator solution of the following materials was prepared: Butyl Cellosolve 35.4 Lupersol PMS (t-butyl peroctoate) 13.6 The following materials were charged into a reaction vessel fitted with a stirrer, condenser, nitrogen sweep, and two gradual addition apparatuses: Butyl Cellosolve 88.0 Monomer mixture 40.8 The batch was heated to 1 100C. and 6% of the initiator solution was added.

Following a fifteen minute hole period the remainder of the monomer mixture and the initiator solution was added proportionally over four hours while maintaining 11 0+300C. Following these additions a mixture of 1.8 parts Lupersol 70 (t-butyl peracetate) and 5.8 parts butyl Cellosolve was added to the batch and the temperature increased to 1700C. ("Lupersol" is a Registered Trade Mark). The resulting acrylic parent polymer of prepolymer (47.87BA/35.91 MMA/16.21AA) has a calculated Tg of 7"C. at 170"C. a mixture of 134.5 parts N-methyl-Nhydroxyethyl linseed oil fatty acid amide and 65.0 parts xylene was addled. The temperature decreased to 1530C. During the next 45 minutes, while maintaining the temperature at 150--155"C., 76 parts of a two phase clear solution was distilled from the batch by application of a partial vacuum. Following distillation the batch was cooled to 950C. and a mixture of 68.5 parts 28% aqueous ammonia and 600 parts of deionized water was added to the batch while maintaining good agitation.

At 75"C. the batch was removed from the reaction vessel and packaged in a glass container where the temperature was allowed to fall to room temperature.

The product of this process was a clear aqueous solution with a solids content of 51.4% and a viscosity of 281,000 centipoises. The viscosity average molecular weight was determined to be 42,300. A thin film (1--3 mils) of the above polymer solution containing 0.1% Co++ (as cobaltous acetate) became tack free within five hours and cured in one week at room temperature to slightly yellow, alkali insoluble films. The glass transition temperature of the cured film was about +200C.

Example 2 Preparation of 40BA/30MMA/20MHELAE (Linseed oil)/lOAA having a Mv of about 80,000 The method of Example 1 was repeated but the mercaptoethanol was reduced to 1.7 parts. The product of this process was a clear aqueous solution with a solids content of 50.7% and a viscosity of 342,000 centipoise. The viscosity average molecular weight was determined to be 80,000. A thin film of this material cured similarly to the film described in Example 1, and had a Tg of about 25"C. in the cured form.

Example 3 Preparation of (20BA/42MMA/30MHELAE (linseed oil)/8AA having a Mv of about 20,000 A monomer mixture of the following materials was prepared: Parts Butyl acrylate 181.5 Methyl methacrylate 379.5 Acrylic acid 120.5 Mercaptoethanol 6.8 This monomer blend (26.6BA/55.7MMA/17.7AA) gives a prepolymer having a calculated Tg of about 43"C.

An initiator solution of the following materials was prepared: Butyl Cellosolve 35.4 Lupersol PMS 40.8 "Lupersol" is a Registered Trade Mark.

The following materials were charged into a reaction vessel fitted with a stirrer, nitrogen sweep, condenser and two gradual addition apparatuses: Butyl Cellosolve Monomer mixture 40.8 The batch was heated to 1420C. and 6% of the initiator solution was added. An exotherm to 151 C. was observed. This temperature was maintained for 15 minutes following which the remainder of the monomer mixture and the initiator solution was added over four hours while maintaining the temperature at 150+30C. Fifteen minutes after completion of these additions a mixture of 1.8 parts Lupersol 70 and 5.8 parts butyl Cellosolve was added to the batch. ("Lupersol" is a Registered Trade Mark) The temperature was maintained at 150+2 C. for an additional fifteen minutes after which a mixture of 224 parts N-methyl-N-hydroxyethyl linseed oil amide and 69.0 parts xylene was added gradually over fifteen minutes while still maintaining the temperature at 1 50+20C. The temperature was then allowed to rise slowly to 1550C. over thirty minutes and 30.0 parts of a two phase clear liquid waq distilled from the batch at atmospheric pressure. Following distillation the batch was cooled to 950C. and a mixture of 50.3 parts 28% aqueous ammonia and 587 parts deionized water was added to the batch while maintaining good agitation. At. about 70"C. the batch was removed from the reaction vessel and packaged in a glass container where the temperature was allowed to fall to room temperature.

The product of this process was a clear aqueous solution (referred to below as Copolymer 3 solution) with a solids content of 53.1% and a viscosity of 11,230 centipoise. The viscosity average molecular weight was determined to be 22,500. A thin film (1--3 mils) of the polymer solution containing 0.1% Co++ (as cobaltous acetate) became tack free within five hours and cured in two weeks at room temperature to a slightly yellow, alkali insoluble film with a Tukon Hardness of about 1.5 and a glass transition temperature of about 25"C.

A pigment grind was prepared using a Cowles dissolver and the following materials: Pigment Grind A Parts Dispersant, *25% TS (total solids) 1.9 Copolymer 3 solution, 53.6% TS 12.3 Deionized water 20.3 TiO2, R-900 HG 65.5 *A copolymer of maleic anhydride and diisobutylene, in a 1:1 mole ratio.

A very smooth pigment grind was obtained on addition of the TiO2 to the liquid ingredients. The mix was stirred on the Cowles mixer at 35004000 ft/min. for 30 minutes. The grind was let down as follows, using a conventional stirrer: Grind A 34.5 Copolymer 3 solution at 25% TS w/0.1% Co++ (as the acetate) on total polymer solids 65.5 The resultant paint had a viscosity of 2700 cps., a pH of 8.5, and on drawdown had a 60 gloss of 80 with a slight yellowish tint. Its tack free time was significantly better than that of commerical solvent alkyd paints with similar gloss properties.

Removal of the dispersing agent resulted in a perfectly satisfactory pigment grind. The ratios employed: Pigment Grind B Parts Copolymer 3 solution, 53.6% TS 12.5 Deionized water 20.7 Tit3, R-900 HG 66.8 As above, a Cowles dissolver was used at a peripheral speed of 3500 to 4000 ft/min. to disperse the pigment. The resultant grind was quite smooth, and was much more easily prepared than conventional semi-gloss grinds. The grind was let down with additional water-soluble polymer, as follows: Pigment Grind B 34.5 Copolymer 3 solution, 25% TS with 0.1% cobaltous acetate on total polymer solids 65.5 This paint at an approximate volume solids of 30% and a PVC of 25% with a viscosity of 1750 cps at a pH of 8.5 had goo.d brushability with good flow and levelling, excellent gloss, and a slightly yellowish tint.

Conventional propylene glycoUpolyelectrolyte dispersant grinds can also be used; in this case the soluble polymer replaces the latex in the let down stage. A typical grind: Pigment Grind C Parts Dispersant, *25% TS 3.1 Nopco NDW Dispersant 5.6 Propylene glycol 19.5 Tit3, R-900 HG 76.8 "Nopco" is a Registered Trade Mark.

*Maleic anhydride-diisobutylene copolymer.

As in the other cases, a Cowles dissolver was used in preparing the grind.

The let down stage, performed with a conventional stirrer, consisted of the following: Pigment Grind C 27.3 Deionized water 5.6 Copolymer 3 solution, 30% TS 67.1 The metallic dried in the Copolymer 3 solution was varied as tabulated below: Paint No.3 -1 -2 -3 -4 -5 -6 drier1 0.1% 0.05% 0.05% 0.05% 0.05% 0 Co++ Co++ Co++ Co++ Co++ - 0.05% 0.05% 0.05% 0.05% 0 Mn++ Zn++ Zr++ Pb++ 1% Metal on total Copolymer 3 solids The resultant paints had very good gloss, particularly depth of gloss or image gloss, reflected in 20 gloss measurements. These are summarized below along with 60 gloss and paint viscosity and pH Paint No.3 -1 -2 -3 -4 -5 -6 pH 8.5 8.5 8.5 8.4 8.3 8.4 viscosity, cps 4300 3750 4500 3700 3450 3600 20 gloss 67 71 61 59 67 - 600 gloss 84 81 79 78 84 86 A conventional latex control, had 60 gloss of 65; the 20 value would typically be 2025 .

An additional variant with good gloss properties is a blend of the water-soluble polymer with a conventional acrylic latex (EA/MMA/MAA 57/42/1) on a 20/80 basis. The following proportions were used: Parts Pigment Grind C 33.2 Deionized water 6.8 Latex, 46.5% TS 39.5 Copolymer 3 solution, 30% TS w/0.1% Co++ 20.5 This paint exhibited 20"/600 gloss of 31/80, not as good as for the examples above incorporating only the water-soluble polymer, but significantly better than the gloss of a paint formulated without copolymer 3 as follows: Pigment Grind C 36.1 Latex, 46.5% Total Solids 57.3 Propylene Glycol 5.0 Texanol 1.6 which had a 600 gloss of 65. (Its 200 gloss was not measured, but typical values observed for equivalent formulations averaged 28.) Example 4 Preparation of (20BA/42MMA/30MHESAE) (soybean)/8AA Polymer having a Mv of about 20,000 The method of Example 3 was repeated with an equal weight of N-methyl-Nhydroxyethyl soybean oil acid amide in place of N-methyl-N-hydroxyethyl linseed oil acid amide. The product of this process was a clear aqueous solution with a solids content of 53.4% and a viscosity of 19,000 centipoise. The copolymer acid titer was 1.13 meq/gram of polymer. A thin film (1--3 mils) of the above polymer solution containing 0.1% Co++ (as cobaltous acetate) cured in two weeks at 600C. to a slightly yellow alkali insoluble film of Tukon Hardness about 2.0.

Example 5 Preparation of (40BA/20MMA/20MHELAE) (linseed oil)/20AA Polymer having a MV of about 20,000 The method of Example 3 was repeated with the butyl acrylate changed to 326 parts, the methyl methacrylate to 163 parts, the acrylic acid to 191.5 parts, the mercaptoethanol to 3.41 parts, the N-methyl-N-hydroxyethyl linseed oil amide to 134.5 parts, the aqueous ammonia to 138 parts and the deionized water to 542 parts.

The acrylic backbone (47.9BA/24MMA/28.1AA) has a calculated Tg of 8"C.

The product of this process was a clear aqueous solution of solids content 50.7% and a viscosity of 14,500 centipoise. The viscosity average molecular weight was determined to be 21,000.

Example 6 Preparation of 20BA/42MMA/30MHELAE (linseed oil)/8AA Polymer having a Mv of about 20,000; Triethyl Amine Neutralization The method of Example 3 was repeated with 111.1 parts of triethylamine in place of the 28% ammonia solution and the deionized water decreased to 526.6 parts. The product of this process was a slightly hazy aqueous solution of solids content 53.6% and a viscosity of 11,650 centipoises. A thin film (1--3 mils) of this polymer cured similarly to the polymer described in Example 3.

Example 7 Preparation of (SBA/42MMA/45MHELAE) (linseed oil)/8AA Polymer having a Mv of about 20,000 The method of Example 3 was repeated with the butyl acrylate changed to 53.8 parts, the methyl methacrylate to 456.0 parts, the acrylic acid to 172.4 parts, the Nmethyl-N-hydroxyethyl linseed oil amide to 403 parts, the 28% aqueous ammonia to 66.7 parts and the deionized water to 571 parts. The acrylic backbone (7.9BA/66.8MMA/25.3AA) has a calculated Tg of 84"C.

The product of this process has a hazy aqueous solution of solids content 56.7% and a viscosity greater than 100,000 centipoise, and is hereinafter referred to as Copolymer 7 solution. A thin film (1-3 mils) of this polymer solution containing 0.1% Co++ (as cobaltous acetate) cured to a yellow, alkali insoluble film of Tukon Hardness about 3.0 and a Tg of approximately 500C. after two weeks at 250C.

Copolymer 7 solution was incorporated in the preferred grind for these watersoluble vehicles, incorporating only pigment, polymer, and water and eliminating the need for coalescent, wet edge aids, dispersants, as follows: Pigment Grind D Parts Copolymer 7 Solution, 25% TS 49.2 Deionized water 1.6 TiO2, R-900 HG 49.2 Standard techniques using the Cowles dissolver were followed. The grind was let down with additional water-soluble polymer incorporating varying levels of metallic drier. The overall recipe for this series included: Paint No. -l -2 -3 -4 Pigment Grind D 44.1 44.1 44.4 36.4 Copolymer 7 solution, 24% 55.9 55.9 52.4 46.0 TS+Drier Deionized water 0- 0 6.2 17.6 1Drier levels for Paint Nos. 7-1, 2, 3, 4, were 0, 0.1, 0.25 and 0.5% Co++ on polymer solids respectively, as cobaltous acetate.

These paints had pH's, viscosities, gloss range of 82-94 and other properties characteristics of the earlier paint series. In addition, the alkali scrub reslstance was measured using a Gardner scrub machine with 1 Ib. boat, 1% Tide (detergent) solution for 500 cycles; the 60 gloss before and after scrub was monitored. ("Tide" is a Registered Trade Mark). The substrates were 7 mil drawdowns on black vinyl charts. Paint No. 7-1 (no drier) was completely removed from the panel after a three day air dry; after one week 30% of the film was removed. After a one day air dry the gloss of Paint No. 7-4 (0.5% Co++) went from 92 to 81 after the 500 cycle scrub, whereas after 7 days air dry the gloss change was from 89 to 82 or -8%. Two days dry time was sufficient for 90% gloss retention at 0.25% Co++.

Example 8 Preparation of 30BA/40MMA/20MHELAE) (linseed)/lOAA Polymer having a Mv of about 40,000 The method of Example 1, with the exception that the butyl acrylate was changed to 245 parts and the methyl methacrylate to 327 parts, was employed through the completion of the addition of the monomer mixture to the reaction vessel. This monomer mix (35.9BA/47.9MMA/16.2AA) gives a calculated Tg of 26"C. Following the monomer mixture addition the batch was heated to 1500 C. and a mixture of 1.8 parts Lupersol 70 and 5.8 parts butyl Cellosolve was added and the temperature maintained. After fifteen minutes a mixture of 134.5 parts Nmethyl-N-hydroxyethyl linseed oil amiaeand 63 parts xylene was added gradually over about 10 minutes while maintaining the temperature at 1 50+20C. The temperature was then allowed to rise slowly to 1550C. over thirty minutes and 24 parts of a two phase clear liquid was distilled from the batch at atmospheric pressure. Following distillation the batch was cooled to 98"C. and a mixture of 68.5 parts 28 /, aqueous ammonia and 600 parts deionized water was added to the batch while maintaining good agitation. At 69"C. the batch was removed from the reaction vessel and packaged in a glass container where the temperature was allowed to fall to room temperature.

The product of this process was a clear aqueous solution with a solids content of 47.9% and a viscosity of 67,500 centipoises. The copolymer acid titer was determined to be 1.34 meq/gram of polymer and the viscosity average molecular weight 58,000. A thin film of this polymer solution containing 0.1two Co++ (as cobaltous acetate) (copolymer 8 solution) cured in two weeks to a slightly yellow, alkali insoluble film with a Tukon Hardness of about 2.5 and a glass transition temperature of about +40"C.

Excellent pigment grinds and paints were prepared from this polymer. A standard Cowles grind was prepared as follows: Parts Copolymer 8 solution, 47.9% 25.1 Deionized water 26.7 TiO2, R-900 HG 48.2 The grind was let down with additional Copolymer 8 solution and water carefully added until the consistency appeared right for brushout. The final mix contained: Pigment Grind 66.5 Copolymer 8 solution, 23.5% -26.8 Deionized water 6.7 This paint had brushability, good gloss, and good flow/levelling, comparable to earlier paints prepared from copolymers 3 and 7.

Example 9 Preparation of 30BA/40 Styrene/20MHELAE (linsed)/l0AA having Mv of about 40,000 The method of Example 8 was used with the exception that N-methyl-Nhydroxyethyl safflower oil amide was substituted for N-methyl-N-hydroxyethyl linseed oil amide.

The product of this process was a clear aqueous solution of solids content of 51.7% and a viscosity of 176,000 centipoise. A thin film of this material cured in the manner described in Example 8 exhibited similar film behavior with the exception that the cured film was of lighter color.

Example 10 Preparation of 30BA/40MMA/15MHEDCAE (dehydrated castor)/SMHETAE (tung)/lOAA Polymer having a Mv of about 40,000 The method of Example 8 was used with the exception that a mixture of 168 parts N-methyl-N-hydroxyethyl dehydrated castor oil amide and 56 parts Nmethyl-N-hydroxyethyl tung oil amide was used in place of the N-methyl-Nhydroxyethyl linseed oil amide.

The product of this process was a clear aqueous solution of solids content 48.7% and a viscosity of 257,000 centipoise. The copolymer acid titer was determined to be 1.37 meq/gram of polymer. A thin film (1--3 mils) of this polymer containing 0.1% Co++ (as cobaltous acetate) became tack-free within five hours and cured in six days to a slightly yellow, alkali insoluble film of Tukon Hardness about 3.4.

Example 11 Preparation of 30BA/40 Styrene/20MHELAE (linseed)/l00AA Polymer (Mv about 40,000) The method of Example 8 was used with the exception of substitution of styrene for methyl methacrylate, giving a calculated Tg for the acrylic prepolymer (35.9BA/47.9S/16.2AA) of 26"C.

The product of this process was a clear aqueous solution of solids content 49.7% and a viscosity of 304,000 centipoise. The copolymer acid titer was 1.44 meq/gram of polymer. A thin film (1--3 mils) of this polymer containing 0.1% Co++ (as cobaltous acetate) cured in six weeks at 250C. to a slightly yellow, alkali insoluble film of Tukon Hardness about 7.5.

Example 12 Polymer of 43BA/27AN/20MHELAE (linseed oilYl0AA (Mv about 40,000) The method of Example 8 was used with the exception that the butyl acrylate level was increased to 350 parts and acrylonitrile substituted for methyl methacrylate at a level of 221 parts. The backbone acrylic polymer (51.4BA/; 32.4An/16.2AA) has a Tg (calculated) of OOC.

The product of this process was a clear aqueous solution of solids content 49.4% and a viscosity of 490,000 centipoise. A thin film (1--3 mils) of this polymer cured in six we 61.2 parts N-methyl-N-hydroxyethyl tung oil amide was used in place of the Nmethyl-N-hydroxyethyl linseed oil amide, and 3) the aqueous ammonia and deionized water changed to 62.5 parts and 548 parts respectively. The acrylic preopolymer of 43.6BA/43.6MMA/12.8AA has a calculated T6 of 14 C.

The product of this process was a clear solution of solids content 48.8% and a viscosity of 308,000 centipoise. A thin film (1--3 Mils) of this polymer containing 0.1% Co++ (as cobaltous acetate) cured in two weeks at room temperature to a slightly yellow, alkali insoluble film of Tukon Hardness about 1.5. A polymer of 10BA/27.5BMA/40iBMA/IOMHETAE/12.5AA had similar properties.

Comparative Example A Polymer of 20BA/42MMA/30MHESTAE (Stearate) 8AA (Mv about 20.000) This is a saturated fatty acid which is disclosed in U.S. Patent No. 3,590,016.

The method of Example 3 was repeated with 456 g. of a 49.2% solution of Nmethyl-N-hydroxyethyl stearamide in xylene in place of the N-methyl-Nhydroxyethyl linseed amide in xylene solution. The product of this process was a cloudy solution which clarified on heating to 60"C. The solids content was 53.4%.

The viscosity at room temperature was 37,200 centipoise. A thin film (1--3 mils) of this polymer solution containing 0.1% Co++ (as cobaltous acetate) remained soft, tacky and alkali soluble indefinitely.

Comparative Example B This is Example 16 of U.S. Patent No. 3,590,016. The acrylic prepolymer (89.4MMA/10.6MAA), having a calculated Tg of about 105"C. is reacted with the hydroxyethyl amide of safower oil fatty acids, to give a polymer of the composition 79.2MMA/14.5HESAFE/6.3MAA.

This example was repeated as described in the patent with the exception that prior to the final dilution with water and KOH the batch was split into two portions. One portion was neutralized with KOH/H2O as described-in the patent and the other with an equivalent amount of ammonia/water.

According to the patent, the prepolymer is obtained as a solution (col. 12, line 45) but in this attempt to repeat the example a heterogeneous mixture was obtained. The mixture eventually becomes homogeneous on additions of the amide and solvent.

Results Portion I-B Portion lI-B (KOH Neut.) (NH3 Neut.) Appearance slightly hazy cloudy % T.S. 42.0 44.2 Visc. (cps) 18,500 38,000 Titer meq. NH3/g. T.S. 0.457* meq. acid/g. T.S. 0.710** 0.706* *Note: This level of ammonia does not fully neutralize the polymer. It is equimolar with the level of KOH used in the patent. Addition of enough more NH3 to neutralize fully the polymer yields a clear homogeneous solution.

**The Patent --0.696 meq. acid/g. T.S.

Theory (100% reaction)---0.710 meq. acid/g. T.S.

Comparative Example C Final Composition 35.80 S/56.65 HELAE/7.54AA HELAE-hydroxyethyl linseed amide ester Example 17 of Patent No. 3,590,016 was repeated as described in the patent with the exception that prior to the final dilution with water (col. 13, line 30) the batch was divided into three portions. Portion A was neutralized and diluted with KOH (N.25 equivalents on polymer acid) and water with agitation as described in the patent. This yielded a polymer dispersion. Portion B was treated as the first except that an equimolar level of ammonia was used in place of KOH. This also yielded a polymer dispersion. Portion C was diluted with a full equivalent of ammonia (on polymer acid) and only enough water to yield a clear solution of about 47% T.S.

Both dispersions were very unstable. Gross sedimentation was observed within 18 hours. Also the odor of all three samples was extremely strong. This odor was a characteristic mercaptan odor and is probably due to the t-dodecyl mercaptan used in the polymerization.

Results Portion I-C Portion Il-C Portion Ill-C Appearance milky white* milky white* clear solution % T.S., excluding Sediment 10% 10% 46.7 Visc. (cps) 100 100 9,200 Titer meq. NH3/gm T.S. ** ** 1.18 acid meq/gm. T.S. 1.33* *Dispersion sedimented within 18 hours **Titer of dispersion meaningless as compared with solution.

***Theory (100% reactiontl.0l meq. acid/gm T.S.

The Patent--1.39 meq. acid/gm T.S. (70% reaction) Oven Stability (10 days/600C.) TABLE III Copolymer acid titer Viscosity (cps) (meq/gm T.S.) Portion Initial 10 days/600C. Initial 10 days/600C.

I-B 18,500 22,000 0.710 0.832 lI-B 38,000 40,200 0.706 0.708 Ill-C 9,200 8,900 1.33 1.43 Cure Study Date on the cure of polymers prepared by Comparative Examples B and C are given in Table IV. The last product is a typical polymer used in this invention.

Conclusions Example B The samples prepared according to this example are unsatisfactory for the following reasons: 1) Films are too hard and brittle 2) Not enough cure to develop satisfactory alkali resistance 3) The sample neutralized with KOH has poor hydrolytic-stability as indicated by the increased acid titer on heat aging.

Example C The dispersed samples were unsatisfactory because of the poor sedimentation stability. In fact the samples sedimented so rapidly it was not possible to cbmplete their evaluation. The solubilized variation of this example exhibited adequate cure and hydrolytic stability; however, the obnoxious odor of the solution plus the excessive hardness and color of the cured film make this polymer unacceptable.

TABLE IV Cure Study 1.5 mil (dry) films containing 0.1% Co++ 16 hr.60 C. 2 wk/25 C.

Neut. Tukon4 Sol. Tukon Sol.

Example Composition Base Tg C. Tg34 C. Color Hardness Fraction Color Hardness Fraction I-B 79.2MMA/14.5 KOH 105 - 0 14.0 0.928 0 - 0.888 HESAFAE/6.3MMA II-B 79.2MMA/14.5 NH3 105 86 1 16.7 0.615 1 15.0 0.807 HESAFAE/6.3MMA III-C 35.8S/56.65 NH3 105 71 6 13.2 0.168 5 9.6 0.349 HELAE/7.54AA Ex. 16 (this 30BA/42MMA/15 NH3 25 2 2 2.16 0.172 1 1.4 0.233 invention) MHEDCAE/5 MHETAE/8AA 0-no colour; 5 very colored Fraction of film soluble in 1/1 mixture by volume of 10% ammonia and isopropanol. The lower the soluble fraction the more highly cured the film.

Prepolymer as calculated.

4Cured film of final polymer.

Claims (14)

WHAT WE CLAIM IS:

1. A method of coating which comprises applying a polymer composition to a substrate and drying and curing the composition, or allowing it to dry and cure, in the presence of air, said composition comprising: (A) an aqueous alkaline solution of an addition polymer solubilized in the solution by ammonia or a volatile amine, the polymer containing: (i) from 5 to 60 parts by weight of units of the formula:

(ii) from 20 to 90 parts by weight of units of the formula:

(iii) from 5 to 20 parts by weight units of one or more unsaturated carboxylic acids, as hereinbefore defined, and, (iv) the balance, if any, to make 100 parts by weight of units of one or more other ethylenically unsaturated addition polymerizable monomers; wherein R' is H, (C1-C5)-alkyl, halogen, -CN, -CH3COOR, -COOR or -CH3COOH, where R is (C1-C8)-alkyl; R2 is (CR37)n wherein R7 is H r -CH3 and n is I or 2; R3 is H or (C1-C8)-alkyl; R4 is an unsaturated air-curable aliphatic hydrocarbon radical; R5 is H, -COOH, -CONH2 or -COOR, where R is (C1-C6)-alkyl; R6 is an aliphatic or cycloaliphatic radical containing from 1 to 20 carbon atoms; the amount of units (iii) being sufficient to provide the polymer with a carboxy content of from 0.5 to 3 meq/g. of polymer and the amount of carboxy groups in the form of salt groups with said amine or ammonia being sufficient to confer water solubility on the polymer, units (ii) being derived from monomer whose homopolymer has a Tg of from -800C to 1200C, the polymer having a viscosity average molecular weight of from 10,000 to 100,000 and a cured film of the polymer having a Tg of from -20"C to 650C and a Tukon hardness of from 0.2 to 10, and, optionally, (B) a metal compound drier in an amount of up to 0.5% by weight, on a metal basis, of the total weight of the polymer in the composition.

2. A method as claimed in Claim I wherein units (iii) have the formula:

where R' and R6 are as defined in Claim 1.

3. A method as claimed in Claim 1 or 2 wherein the polymer contains from 10 to 40 parts by weight of units (i).

4. A method as claimed in any of Claims I to 3 wherein the quantity of ethylenically unsaturated acid units in the polymer is sufficient to provide a carboxy content of from 0.6 to 2.5 meq/g. of polymer.

5. A method as claimed in any of Claims 1 to 4 wherein the viscosity average molecular weight of the polymer is from 20,000 to 80,000.

6. A method as claimed in any of Claims 1 to 5 wherein the polymer contains: (a) 5-30 parts by weight of units (i); (b) 1050 parts by weight of units of one or more esters of acrylic and/or methacrylic acid, which when homopolymerized give a polymer having a Tg of from 0 to 800 C; (c) 2070 parts by weight of units of one or more of esters of acrylic and/or methacrylic acid, vinyl aromatic hydrocarbons and unsaturated nitriles, which when homopolymerized give a polymer having a Tg of from 20 to 1200C; (d) 5-15 parts by weight of units of at least one ethylenically unsaturated carboxylic acid, and optionally, (e) up to 20 parts by weight of units of one or more different ethylenically unsaturated monomers which confers hydrophilicity to the polymer and enhances its solubility in aqueous liquids, the total of (a), (b), (c), (d) and (e), when present, being 100 parts by weight.

7. A method as claimed in Claim 6 wherein (b) comprises units of one or more of ethyl acrylate, butyl acrylate, 2ethylhexyl acrylate, sec-butyl acrylate, isobutyl acrylate and isopropyl acrylate; (c) comprises units of one or more of methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, styrene, vinyl toluene and acrylonitrile; (d) comprises units of one or more of acrylic acid, methacrylic acid, maleic acid and itaconic acid, and (e) when present, comprises units of one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate.

8. A method as claimed in any of Claims 1 to 5 wherein the polymer contains:

1. 5-30 parts by weight of units (i);

2. 4590 parts by weight of units of butyl methacrylate;

3. 5-15 parts by weight of units of one or more ethylenically unsaturated carboxylic acid in an amount so as to provide a carboxy content in the polymer of from 0.6 to 2.5 meq/g. of polymer, and, optionally,

4. up to 20 parts by weight of units of at least one different ethylenically unsaturated monomer which confers hydrophilicity to the polymer and enhances its solubility in aqueous liquids; to total of 1, 2, 3 and, when present, 4 being 100 parts by weight.

9. A method as claimed in any preceding claim where R4 is the residue of one or more of the drying oil acids: tung oil, linseed oil, dehydrated castor oil, safflower oil, conjugated safflower oil, soybean oil and oiticica oil.

10. A method as claimed in Claim 9 wherein R4 is derived from a blend of drying oil acids comprising 50--90"i= by weight of one or more of dehydrated castor oil, safflower oil, conjugated safflower oil and soybean oil and 1050 Ó by weight of tung oil acid.

II. A method as claimed in any preceding claim wherein the composition comprises, on a solids basis, 10 to 70 , by weight of water-soluble polymer (A) and 30 to 90 Ó by weight of a water-insoluble latex polymer.

12. A method as claimed in Claim 1 substantially as described in any of the foregoing Examples I to 4 and 6 to 15.

13. An article treated by a method according to Claim 1.

14. An article treated by a method according to any of Claims 2 to 12.

Reference has been directed in pursuance of sectlon 9, subsectlon (l) ot the Patents Act 1949, to patent No. 1277791