CA1071789A - Method for producing solvent free water based enamels - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Water-based paints having improved properties and application characteristics are disclosed. The paint, exclusive of optional components such as pigments, particulate fillers and catalysts, comprises a liquid, continuous aqueous phase. About 30 to about 50% by weight of this phase exclusive of the aforecited optional components, is made up of A mixture of (a) an amino resin crosslinking agent; (b) a mixture of at least two copolymers of acrylic monomers; and (c) an amine. The balance is water or, in certain embodiments, water and an organic solvent. The mixture of copolymers comprises (1) about 5 to about 50, preferably about 10 to about 30, parts by weight of a "solution polymer", i.e,, a carboxy-functional copolymer of acrylic monomers that (i) is at least partially neutralized with an amine, (ii) is soluble in said aqueous phase, (iii) has average molecular weight (?n) in the range of about 3,000 to about 20,000, and (iv) has Tg in the range of -15° to 50°C., and (2) about 50 to about 95, preferably about 70 to about 90, parts by weight of an "emulsion polymer", i.e., a copolymer of acrylic monomers having carboxy, hydroxy or carboxy and hydroxy functionality that (i) is essentially insoluble in said continuous phase, (ii) has average molecular weight (?n) in the range of about 3,000 to about 20,000, and (iii) has Tg of -15° to 50°C. The amino resin crosslinking agent is present in an amount in the range of about 15 to about 35 weight percent of the sum of the weight of solution polymer and the weight of emulsion polymer.
The amine is a water-soluble amine and is present in an amount sufficient to solubilize the solution polymer in the aqueous phase at a pH range of about 7 to about 10, most commonly in the range of about 7.1 to about 8.5.

Description

` 1071789 The present invention relates to water-based paints.
Water-based paints of the prior art have included "solution paints" and "emulsion (or latex) paints" with distinction being made with reference to the manner in which the sole or principal binder polymer is dispersed within the aqueous medium.
In those paints wherein the sole or principal binder polymer is soluble in the aqueous medium, the poly-mer is ordinarily of low molecular weight. These paints can be formulated to provide coatings of very high gloss.
They tend to be slow drying and prone to sagging during application ana to solvent popping during baking under high humidity conditions. Application solids are much lower than comparable latex paints.
The emulsion or latex paints have employed as their sole or principal binder polymer a polymer of very high molecular weight, i.e., in the range of about 100,000 to about 1,000,000 or higher. Such paints have been charac-terized by rapid drying and comparatively ~ow gloss rela-tive to paints based on water-soluble polymers.
Water-soluble polymers of high molecular weight have been added to latex paints as thickeners. Character-istically, such thickener polymers are used in very small ~ amounts, e.g., of the order of one percent.
- It has been discovered that water-based paints having a superior combination of physical properties and application characteristics can be obtained by using certain novel combinations of solution polymers and emul-sion polymers. The coatings obtained from these hybrid 3Q compositions exhibit high gloss and generally excellent appearance.

1C~717139 The hybrid, water-based, paint compositions of this invention employ in combination a low molecular weight emulsion polymer and a low molecular weight solution polymer with the latter being present in an amount sufficient to contribute significantly to the composition of the polymeric binder, i.e. 9 at least about 5 weight percent of this polymeric combination. Thus, they differ from the conventional emulsion type paints employing a water-soluble thickener polymer in at least three compositional respects irrespective of chemical functionality, namely, (1) the emulsion polymers of the instant paints have significantly lower molecular weights, (2) the solution polymers of the instant paints have significantly lower molecular weights, and (3) the solution polymers of the instant paints are employed in significantly higher concentrations than are the water-soluble thickener polymers.
More specifically, the hybrid paint compositions of this invention, exclusive of optional components such as pigments, particulate fillers and catalysts, have a liquid continuous aqueous phase. About 30 to about 50% by weight .r of this phase, exclusive of the aforecited optional components, is made up of a mixture of (a) an amino resin crosslinking agent; (b) a mixture of at least two copolymers of acrylic monomers; and (c) an amine. The balance is water .
or, in certain embodiments, water and an organic solvent. The mixture of copolymers comprises (1) about 5 to about 50, preferably about 10 to about 30, parts by weight of a "solution polymer", i.e., a car~oxy-functional copolymer of acrylic - monomers that (i) is at least partially neutralized with an amine, (ii) is soluble in said aqueous phase, (iii) has average molecular weight (~n) in the range of about 3,000 to about 20,000 and (iv) has Tg in the range of -15 to 50C., 1~71789 and (2) about 50 to about 95, preferably about 60 to about 90, parts by weight of an "emulsion polymer"~ i.e.~ a copolymer of acrylic monomers having carboxy, hydroxy or carboxy and hydroxy functionality that (i) is essentially insoluble in said continuous phase~ (ii) has average molecular weight -(~ ) in the range of about 3,000 to about 20,000 and (iii) has Tg of -15 to 50C. The amino resin crosslinking agent is present in an amount in the range of about 15 to about 35 weight percent of the sum of the weight of solution polymer and the weight of emulsion polymer. The amine is a water-soluble amine and is present in an amount sufficient to solubilize the solution polymer in the aqueous phase at a pH range of about 7.1 to about ~.5. In certain embodiments, hereinafter illu~trated~ these hybrid compositions include organic cosolvents while in other embodiments such solvents are not present.
When applied to the substrate to be coated by spraying, these water-based paints including pigments, particulate fillers, and catalysts~ if any~ contain between " 20 about 50 and about 65~o by weight water or in those embodiments - wherein such solvents are used, water and organic cosolvents.
, Paint Preparation A Number of methods can be used to prepare the water-based paints of this invention.
In a first general method, at least one of the polymers, usually the solution polymer, is polymerized in solution in a water miscible or dilutable organic solvent while the other polymer, usually the emulsion polymer, is prepared by an emulsion polymerization in water~ The resultant water-based paint will contain a conventional, essentially non-reactive, water-miscible or dilutable ~7178g organic paint solvent. The concentration of organic solvent in such paints will be at least about 5~ by volume of the volatile phase, i.e., organic solvent and water, and preferably in the range of about 10 to about 20 volume percent of the volatile phase.
In a second general method both the solution polymer and the emulsion polymer are prepared by emulsion polymerization in water. The paints thus prepared are prepared without organic solvents and thus employed free of same. Organic -~ 10 solvents in the amounts used in the first general method may be added to the dispersion, if desired.
A third general method is the same as the first general method except for the difference that in carrying out the emulsion polymerization the surfactant~ i.e., surface active agent or emulsifier, is replaced by a solution polymer - hereinafter more fully described.
A fourth general method is the same as the second general method except for the difference that in carrying out one or both, preferably both, of the emulsion polymerizations -the surfactant is replaced by a solution polymerhereinafter more fully described.
The advantage provided by the third an fourth ~ general methods is that elimination of the conventional i surfactant eliminates the problem Or incompatibility and water sensitibity associated with the use of surfactants.
t~ ' .
~` Pol~mer Composition In Detail (A) The solution polymer in these paints has ` carboxy functionality and may also have hydroxy functionality and/or amide functionality. These polymers contain about 5 to about 30 mole percent of acrylic or methacrylic acid and '' -' ' '. . , ,, '., , - ' . ' 10717~9 70 to 9'j mo]e percent Or olefinically unsaturated monomers

2 ~ cOpolYme~læable with such acid compollerlt Preferably, these .~ I
;, 3 l other ol~rinically llnsaturatef~ monomers are monoacrylate~ or 4 monomethacrylates- In the embodlment wherein the prlmary . ~5 ¦ ~olutlon polymer has only carboxy functiona~ty, these are prererably esters of acryllc acld or methacryllc acid and a 7 ~ ¦ Cl - C monohydric alcohol. C8 - C12 monovlnyl hydrocarbons ~;~j 8,;~ ¦ such as styrene, alpha methyl styrene, t-butyl styrene, and -; 9 -~ ¦ vlnyl toluene may comprlse up to about 30 mole percent Or ~10~ ¦ such polymer. Vinyl monomers ~uch as vinyl chlorlde, aorylonltrlle, methacrylonltrile and vinyl acetate may be .
~, 12~ ¦ included ln the copolymer a~ modlfyln~ monomers. However, 13 ¦ when employed, these modirylng monomers should constitute 14~ only between about O and about 30, preferably O to about 15, ~ ;
~":~,.!,.' 15 mole percent of such polymer. In the embodlment whereln the ~ 16 solutlon polymer has both carboxy functlonallty and hydroxy 'I'?j~ il7 functlonallty, the copolymer contalns about 5 to about 25 ! i ' . ' .
18 - mole percent of acryllc or methacrylic acld, about 5 to about 19 ~ 25 mole percent of a hydroxyalkylacrylate or methacrylate, ~
2a ~ ~ e.g., hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxy- -21 ethyl methacrylate or hydroxypropyl methacrylate, and a 22 remainder of the same monorunctional monomers as set forth f ~ above for the solely carboxy-runctlonal polymer. In stlll

3 24 another embodiment, the polymer has amide functlonallty ln ;
- ~25 addltlon to carboxy fun¢tlonallty. Such a polymer contalns 26 about 5 to about 25 mole percent acrylic acid or methaaryllc 27 acld, about 5 to about 25 mole peroent of acrylamlde, meth-28 acrylamlde, N-methylolacrylamlde, N-methylolmethacrylamlde, or 29 the alkyl ether Or a methylolacrylamlde or a methylolmethacrylamide, e.g., N-isobutoxymethylol-31 ~1 Qorylamlde th the remalnder Or the sQme monorunctionQl ~, ~

i(~7~78~
monomers as set forth above for the solely carboxy-functional polymer. A portion of the amide functional monomer may be replaced with an equimolar amount of one of the aforementioned hydroxyacrylates or hydroxymethacrylates.
Other monomers not heretofore mentioned may be used in these polymers if used in limited concentrations. These include 2-acrylamido-2-methylpropanesulfonic acid and methacryloyloxyethylphosphate, which may comprise up to about 3 of such polymer.
(~) The emulsion polymer in these paints has - carboxy functionality, hydroxy functionality or carboxy and r hydroxy functionality. These polymers contain O to 15 mole ~ percent acrylic acid or methacrylic acid, preferably O to i 10 mole percent, and ~5 to 100 mole percent of other olefinically l unsaturated monomers that are copolymerizable with each other:.:-.
and with the acid component when the latter is used. Such ;
other olefinically unsaturated monomers are the same in type and . '!
of the same percentage distribution range as those heretofore disclosed for the solution polymer with the exception of the acid monomer content above noted.
In those embodiments, wherein both the solution polymer and the emulsion polymer have hydroxy functionality ~
and carboxy functionality, it is preferred to have a greater -concentration of carboxy functionality on the solution polymer relative to the emulsion polymer and a greater concentration of the hydroxy functionality on the emulsion polymer relative to the solution polymer.
Thus, the combinations involved include (a) a carboxy-functional solution polymer and a hydroxy-functional emulsion polymer, (b) a carboxy-functional solution polymer and a carboxy-functional emulsion polymer, (c) a carboxy-functional solution polymer and a carboxy-functional, hydroxy-. !
. ' ' ` ' ~' ' ' , ' ', ' " ~ , ' .

`-~ 107~78~
functional emulsion polymer, (d) a carboxy-functional and hydroxy-functional solution polymer and a hydroxy-functional emulsion polymer, (e) a carboxy-functional, hydroxy-functional solution polymer and a carboxy-functional and hydroxy-functional emulsion polymer, (f) a carboxy-functional and amide-functional solution polymer and a hydroxy-functional emulsion polymer, (g) a carboxy-functional and amide- r functional solution polymer and a carboxy-functional emulsion polymer, (h) a carboxy-functional and amide-functional solution polymer and a carboxy-functional and hydroxy-functional - emulsion polymer, (i) a carboxy-functional, hydroxy-functional, and amide-functional solution polymer and a hydroxy-functional emulsion polymer, (j) a carboxy-functional, hydroxy-functional~
; amide-functional solution polymer and a carboxy-functional emulsion polymer, and (k) a carboxy-functional, hydroxy-functional, amide-functional solution polymer and a carboxy-functional, hydroxy-functional emulsion polymer. Amide functionality may also be incorporated into the emulsion polymer but thi~s is more difficult to achieve efficiently than in the solution polymer, particularly in the case of modified amide functionality, e.g., N-methylolacrylamide.
(C) The amino resin crosslinking agent, may be and is hereafter illustrated as a conventional amino resin crosslinking agent of the type long in use as a crosslinking agent in acrylic enamels, e.g., melamine-~ormaldehyde resins and urea-formaldehyde resins.

DETAILED~ ___N OF FIRST GENERAL METHOD
FOR PREPARING PAINTS DESCRIBED HER~IN
(a) Preparation of Solution Copolymer In preparing the water-soluble copolymer~ the functional monomers and the remaining monoethylenically unsaturated monomers are mixed and reacted by con~entional free radical initiated polymerization in such proportions _ 9 _ ~C~717~39 as to obtain the copolymer desired. A large number of free radical initiators are known to the art and are suitable for this purpose. These include benzoyl peroxide;
t-butyl peroctoate; t-butyl perbenzoate; lauryl peroxide;
t-butyl-hydroxy peroxide; acetylcyclohexane sulfonyl peroxide;
diisobutyryl peroxlde; di-(2-ethylhexyl) peroxydicarbonate;
diisopropyl peroxydicarbonate; t-butylperoxypivalate; decanoyl peroxide; azobis(2-methyl propionitrile); etc. The polymerization -~ is carried out in solution using a solvent which is miscible or di-lutable with water. The solvent concentration at this stage is ordinarily about 30 to 60 weight percent of the polymerization solution. The polymerization is carried out at a temperature between about 45C. and the reflu~ temperature of the reaction mixture. Included among the suitable solvents are n-propyl alcohol, isopropyl alcohol, dioxane, ethylene glycol monomethyl ~ ether, ethylene glycol monoethyl ether, ethylene glycol -' monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, etc. The copolymer thus obtained is neutralized with amine to a pH of about 6 to 10 and diluted to desired viscosity with water or organic solvent.
(b) Preparation of Emulsion Copolymer In preparing the emulsion copolymer, the functional monomers are mixed and reacted by conventional free-radical initiated polymerization in aqueous emulsion to obtain the copolymer desired~
Conventional surfactants, chain transfer agents, and initiators are employed in the emulsion polymerization. The monomer charge is usually emulsified by one or more micelle-forming compounds composed of a hydrophobic part. such as a ,~ ..... . .

~717~39 .
hydrocarbon group containing six or more carbon atoms, and a hydrophilic part, such as hydroxyl groups, alkali metal, ;~^
ammonium carboxylate groups, sulfonate groups, phosphate or sulfate partial ester groups, or a polyether chain. Exemplary emulsifying agents include alkali metal sulfonates of styrene, naphthalene, decyl benzene, and dodecyl benzene; sodium dodecyl sulfate; sodium stearate; sodium oleate; the sodium ;:
alkyl aryl polyether sulfates and phosphates; the ethylene oxide condensates of long chain fatty acids, alcohols, and mercaptans, and the alkali metal salts of rosin acids. These materials and the techniques of their employment in emulsion :!', formation and maintenance are well known in the art. A
chain transfer agent or mixture of chain transfer agents ~; may be added to the reaction medium to limit the molecular weight of the copolymer; such chain transfer agents are generally mercaptans such as dodecanethiol, benzenethiol, 1-octanethiol, pentanethiol, and butanethiol. These are conventional materials and are employed in a conventional manner. The polymerization initiator is composed of one or more water-soluble, free~radical-generating species such as hydrogen peroxide or the sodium, potassium, or ammonium persulfates, perborates, peracetates, percarbonates and the like. The polymerization is carried out at a temperature between about 45C. and the reflux temperature of the reaction mixture. As is well known in the art, these initiators may be associated with activating systems such as redox systems which may incorporate mild reducing agents, such as sulfites and thiosulfites, and redox reaction promoters such as transistion metal ions, and that these allow the polymerization to be carried out at a lower temperature, e.g., 0C. or below. As, however, it is desirable to maintain a low concentration of non-polymeric ionic species in the finished paint formulation in order that the cured paint film may have optimum resistance to water, it is preferred to use a minimum concentration of such optional inorganic salts as ferrous sulfate, sodium bisulfite, and the like.
Those skilled in the art will be aware that other emulsifying agents, polymerization initiators and chain transfer agents may be used which are compatible with the polymerization system herein required and with the attainment of acceptable cured paint film properties.
As will be disclosed later herein, the solution j;~
polymer may also be prepared by emulsion polymerization. In ~! such preparation~ the resultant acid-functional copolymer latex îs converted to a polymer solution by the addition of an appropriate base, usually ammonia or an organic amine.
There are, however, different needs involved in the after-preparation employment of the emulsion polymer that is used as such in formulation of paint and the solution polymer which although prepared by emulsion polymerization is subsequently converted to a solution polymer and used as such. These needs should be taken into consideration in the preparation procedure.
In the use of emulsion polymerization to produce a solution polymer, there is no need for ~he resulting latex to be stable under conditions different from those ensuing at the end of the polymerization process since the latex no longer exists, as such, after the polymer goes into solution upon neutralization. To facilitate such conversion to solution polymers, polymers prepared by emulsion polymerization for use as solution polymers ordinarily contain a higher concentration of carboxyl groups and a lower concentration of decidedly hydrophobic monomers, e.g., 2-ethylhexyl acrylate, relative to the corresponding concentrations in the polymers prepared by emulsion polymerization for use as such.

` ~0717t39 In contrast! latices which are used as such in the formulation of paint are requied to remain essentially as stable latices throughout the processes of polymerization~
paint formulation, and product distribution and use. This implies a requirement of stability, i.e., freedom from coagulum formation through time and under a variety of pH
conditions, solvent environment, etc. These requirements are best met, and hence it is preferred to use, an alkali metal or ammonium persulfate either as the sole polymerization initiator~ or as one constituent of a mixed initiator system.
In those embodiments in which conventional surfactants are used, it is preferred to use a plurality of surfactants, more specifically a combination of anionic and nonionic surfactants, to obtain a more stable latex. Such surfactant mixtures are well known in the art.
(c) Formulation of Paint The polymer solution and the polymer latex pre-pared according to the aforedescribed procedures are subsequently converted into a paint using conventional paint formulation techniques. Typically, a mill base is prepared which comprises the bulk of the pigment and/or partiGulate filler of the paint formulation. The mill base is "let down" i.e., blended with the remainding polymeric and liquid constituents of the final formulation. A mill base, prepared by conventional sand grinding, ball milling, or pebble milling generally comprises all or a part of the water soluble resin, pigments, organic cosolvents, and may also comprise a quantity of amine in excess of that required to solubilize the solution polymer.
To complete the paint, the polymer latex which has been neutralized to a pH range of 5.0 to 10, preferably 5 to 9, is added with mild agitation to the balance of the water 1~7:~1L789 required in the total formulation. The balance of the water-soluble resin~ crosslinking agent, and millbase are added ` slowly with agitation. Additional quantities of pigment may be added subsequently as slurries in organic solvents or as separate mill bases to adjust the colar as desired.
The viscosity of the finished paint is determined and adjusted as required to obtain desired application properties.
; Alternately, all or a portion of the (preferably neutralized) polymer latex, water, organic cosolvent, and amine may be added to the solution polymer and pigments prior to ball milling, sand grinding, or pebble milling.
This procedure is advantageously employed to reduce the viscosity of mill bases prepared using the solution polymers of relatively high molecular weight.
(d) Use of Organic Amines Organic amines are used to neutralize carboxyl groups on the solution polymer and hence to render it soluble in the aqueous dispersion. They are also used to maintain the pH of the finished paint formulation above about 7, e.g., in the range of 7 - 10, preferably between 7 and 9.5, and with certain pigments such as aluminum flakes preferably between 7 and 9, to prevent premature reaction of the functional groups on the acrylic copolymer with the amino resin cross-linking agent. Those skilled in the art will be aware that in certain embodiments the paint dispersion can be made up at a pH outside the pH range for application and later adjusted to the desired pH shortly before it is applied~A portion of the amine, e.g., preferably between about 60 and lOO~o of the amount chemically equivalent to the carboxyl functionality of the polymer is added to the solution polymer directly.
Advantageously, a small additional portion of amine is used 1~7~789 to raise the pH of the emulsion polymer to about 5 to about 10, preferably 5 to 9, prior to finishing the paint formulation so that the mill base is not subjected to the low pH environment of the polymer latex (pH about 2.5).
Suitable amines are amines (1) which are soluble in the aqueous medium of the paint, (2) that ionize sufficiently in such aqueous medium to solubilize the solution polymer, (3) that ionize su~ficiently in such aqueous medium when employed in suitable amouks to provide the paint dispersion with a pH of at least about 7, preferably 7.2 or higher, and thereby keep the rate of reaction between reactive groups of the amino resin (crosslinking agent) negligible prior to curing~ and (4) that allow for rapid curing of the enamel upon heating. Suitable amines include alkyl, alkanol and aryl primary, secondary and tertiary amines.
Preferred are secondary and tertiaryalkyl and alkanol amines having a boiling point within the range of ~0 - 200C. By way of example, these include N,N-dimethyl ethanolamine, N,N-diethylethanolamine, isopropanolamine, morpholine, N-methyl-morpholine, N-ethylmorpholine, N-methylethanolamine, 2,6-dimethylmorpholine, methoxypropylamine, and 2-amino-2-methyl-l-propanol.
(e) Catalysts - Catalysts for the curing of resins described here-in are not normally required to obtain satisfactory film properties If desired, however, for purposes of lowering the fllm baking temperature or of further ;mproving cured film properties, strong acid catalysts can be employed in an amount not in excess of 3~ by weight of the total finished paint formulation.
Said strong acid catalysts may be introduced either as copoly-merizable species incorporated in one or both acrylic - 15 ~

1~717~39 copolymers, e.g., 2-acrylamide-2-methylpropanesulfonic acid, - or as a non-polymerizable additive~ e.g.~ p-toluenesulfonic acid. It is generally preferred not to add such catalysts, however, as they may tend to increase the water sensitivity of the cured film and may deleteriously affect storage stability of the liquid paint.
(f) Cosolvents In those embodiments wherein a volatile organic solvent is employed as a cosolvent, i.e., solution of the solution polymer also being effected by the use of a water-soluble amine, the following solvents are suitable for this use include: n-propyl alcohol, isopropyl alcohol, butanol, 2-butoxyethanol, 2(2-butoxy)ethoxyethanol, n-octyl alcohol, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoethyl etherS diethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate~ etc.

DETAILED DESCRIPTION OF SECOND GENERAL METHOD
FOR PREPARING PAINTS DESCRIBED HEREIN
(a) Preparation of Solution Polymer In this method, the water-soluble copolymer is produced by emulsion polymerization. The functional monomers are mixed and reacted by conventional free-radical initiated polymerization in aqueous emulsion to obtain the copolymer desired~ The resulting acid-functional copolymer latex is con-verted to a polymer solution by the addition of an appropriate base, usually ammonia or an organic amine.
Conventional surfactants, chain transfer agents, and initiators are employed in the emulsion polymerization. The monomer charge is usually emulsified by one or more micelle-107178g sulfate; sodium stearate; sodium oleate, the sodium alkyl aryl polyether or sulfates and phosphates; the ethylene oxide condensates of long chain fatty acids, alcohols, and ~ercaptans, and the alkali metal salts of rosin acids. These materials and the techniques of their employment in emulsion formation and maintenance are well known in the art. As previously pointed out, however, when emulsion polymerization is used to produce a solution polymer, there is no need for the resulting latex to be stable under conditions different from those ensuing at the end of the polymerization process since the latex no longer exists as such after the polymer goes into solution upon neutralizationO To facilitate such conversion to solution polymers, polymers prepared by emulsion polymer-ization for use as a solution polymer ordinarily contain a higher concentration of carboxyl groups and a lower con-centration of decidedly hydrophobic monomers, e.g., 2-ethyl-hexyl acrylate, relative to the corresponding concentrations in the polymers prepared for use as emulsion polymers.
Further, the teaching hereinbefore set forth with respect to the choice of initiators when preparing the latter, i.e.
using an alkali metal or ammoni~m persulfate either as the sole polymerization initiator or as one constituent of a mixed initiator system to avoid coagulum formation through time and under a variety of pH conditions, solvent environ-ment, etc., is applicable where the polymer is to be con-verted to a solution polymer. Such initiators may be used when preparing the solution polymer by emulsion polymerization but conventional peroxide initiators are quite suitable for this. Hence, this method offers an advantage, in this respect, in that the concentration of ionic inorganic contaminants, e.g., sulfate ions, in the ~ - 17 `- 1071789 .
. paint formulation is reduced. A chain transfer agent or ` mixture of chain transfer agents may be added to the reaction medium to limit the molecular weight of the polymer, such, chain transfer agents are generally :
mercaptans such as dodecane-:':

- 17a ~ C~7178~
polymer by emulsion polymerization but conventional peroxide initiators are quite suitable for this. Hence, this method offers an advantage, in this respect, in that the concentration of ionic inorganic contaminants~ e.g.) sulfate ions~ in the paint formulation is reduced. A chain transfer agent or mixture of chain transfer agents may be added to the reaction medium to limit the molecular weight of the polymer, such chain transfer agents are generally mercaptans such as dodecane-thiol, benzenethiol, l-octanethiol, pentanethiol and butanethiol.
These are conventional materials employed in a conventional man-ner. The polymerization initiator is composed of one or more water-soluble, free-radical-generating species such as hydrogen peroxide or the sodium, potassium or ammonium persulfates, per-borates, peracetates, percarbonates and the like. As is well known in the art, these initiators may be associated with activating systems such as redox system which may incorporate mild reducing agents, such as sulfites and thiosulfites and redox reaction promoters such as transition metal ions. As hereinbefore mentioned, however, it is desirable to maintain a low concentration of non-polymeric ionic species in the finished palnt formulation in order that the cured paint film may have optimium resistance to water. Hence, it is preferred to use a minimum comcentration of such optional inorganic salts as ferrous sulfate9 sodium bisulfite~ and the likeO Those skilled in the art will be aware that other emulsifying agents, polymerization initiators and chain trans-fer agents may be used which are compatible with the polymerization system herein required and with the attainment of acceptable cured paint film propertiesO
(b) Preparation of Emulsion Copolymer The emulsion copolymer may be prepared us;ng the same procedures hereinbefore recited for preparation - 1~7178~
of the emulsion copolymer in part (b) of the first general method.
(c) Formulation of Paint The polymer solution and the polymer latex prepared according to the aforedescribed procedures may be subsequently converted into a paint using the same procedures hereinbefore recited for formulation of paint in part (c) of the first general method.
(d) Use of Organic Amines The use of organic amines and amines which are suitable for such use are the same for this general method as hereinbefore described in detail in part (d) of the first general method.
(e) Catalysts The use of catalysts and catalysts which are suitable for curing the resins hereinbefore described and hereinafter illustrated are the same for this general method as hereinbefore described in detail in part (d) of the firs~ general method.
(f) Cosolvents The use and choice of cosolvents for use with this general method may be the same as hereinbefore described in part (f) of the first general method.

DETAILED DESCRIPTION OF THIRD GENERAL METHOD
_FOR PREPARING PAINTS DESCRIBED HEREIN
The third general method for preparing the paints disclosed herein is identical with the first general method hereinbefore described in detail except for the difference that all or a part of the surfactant, i.e., surface active agent or emulsifier, employed in preparing the emulsion polymer, ```` ` 1071789 is replaced with a stabilizer polymer, that is identical with or similar to, the solution polymer heretofore described in the first and second general methods and employed as a primary constituent of the paints described herein.
The stabilizer polymer of the third and fourth general methods is carboxy functional and soluble in the aqueous phase of these paint dispersions and is either the same as the primary solution polymer, heretofore discussed, or similar to such solution polymer and compatible with the system. The average molecular weight (Mn) of the stabilizer polymer may be the same as that of the primary solution polymer, i.e., between 3,000 and 20,000 but advisedly is of lower molecular weight than the primary solution polymer.
Preferably, the average molecular weight of this third copolymer is in the range of about 3,000 to about 8,000.
Its Tg is in the range of -15 to 50C. ~7hen the stabilizer polymer is used in lieu of the surfactant to prepare either the solution polymer or the emulsion polymer, it is present in a concentration in the range of about 0.025 to about 10, preferably about 0.5 to about 5 parts by weight of the dispersion.
The stabilizer polymer may be prepared by any of several methods, including (1) the method used to prepare the solution polymer of the first general method of paint preparation, i.e., polymerization in solution in a water miscible or dilutable organic solvent; (2) the method used ; to prepare the solution polymer for the second general method of paint preparation, i.e., emulsion polymerization using an emulsifier or surfactant; (3) emulsion polymerization using in lieu of a surfactant a small amount of the intended polymer from a previous preparation; and (4) a method of ~ -~

1(~71789 emulsion polymerization described hereinafter whlch employs neither surfactant nor a water soluble polymer in lieu thereof.
In the latter, conventional chain transfer agents and polymer-îzation initiators are used as described hereinbefore for the preparation of a solution polymer by emulsion polymerization.
A mixture of monomers including carboxyl-functional monomers and a chain transfer agent is added slowly to a stirred mixture -~of initiator and water maintained at a suitable reaction temperature, e.g., between 45 and 95C. It is preferred to add simultaneously with the monomer mixture an additional quantity of polymerization initiator to sustain a sufficient initiator concentration throughout the polymerization. The polymer latex so obtained is filtered and neutralized with ammonia or water-soluble amine to render it water soluble.

DETAILED DESCRIPTION OF FOURTH GENERAL METHOD
FOR PREPARING PAINTS DESCRIBED HEREIN
The fourth general method for preparing the paints disclosed herein is identical with the second general method hereinbefore described in detail except for the difference that all or a part of the surfactant used to prepare the solution polymer, the emulsion polymer or, preferably, both the solution polymer and the emulsion polymer is replaced by a stabilizer polymer, such as hereto~ore described in detail in the description of the third general method.

This invention will be more fully understood from the following illustrative examples:

.

_ 21 -EXAMPLE I
A heat-curable coating composition suitable for automotive topcoat application is prepared from an aqueous acrylic copolymer latex, an aqueous solution of a second acrylic copolymer, and an amino resin crosslin'cing agent, here a melamine resin, in the manner hereinafter set forth:
Step 1 Preparation of Acrylic Copolymer Latex Monomers and AdditivesParts by Weight methyl methacrylate 41 methacrylic acid 4 ethyl acrylate 35 butyl acrylate 20 l-octanethiol "TRITON" (Trade Mark) X-200( ~ 1 Triton X-305(2) 4.5 Water . 70 potassium persulfate 0.4 Reactor Charge i ,~ .
Water 30 ; 20 Triton X-200 2 ~:
potassium persulfate 0.1 a product of Rohm and Haas Company, characterized :` as an anionic surfactant containing 28~ active component described as the sodium salt of an alkyl aryl polyether . sulfonate.
(2) a product of Rohm and Ilaas Company, character-ized as a nonionic surfactant containing 70% active component described as an alkylarylpolyether alcohol averaging 30 ethylene oxide units per molecule.

The reactor charge is heated to 50C. in a reaction vessel equipped with a stirrer, re~lux condenser, nitrogen inlet type, addition funnel and thermometer. The monomer mixture is mixed with the listed additives and an emulsion is formed by stirring. The monomer emulsion is added over a four and one-half hour period. The temperature is maintained at 50 + 5C throughout the monomer addition and for 2 hours thereafter. A nitrogen sparge is maintained throughout.
The latex so formed is cooled to room temperature, filtered, and formulated into paint as hereinafter described. The molecular weight of the polymer so prepared (M ) is about -6,000. Its glass transition temperature, Tg, is about 14C
(calculated from the monomeric composition without regard to molecular weight as are all Tg values herein given).

Step II Preparation of Water Soluble Acrylic Polymer Monomer Mixture and I~itiatorParts by Weight methacrylic acid 15.0 methylmethacrylate 15.0 styrene 20.0 butyl acrylate 40.0 - butyl methacrylate 10.0 t-butylperoctoate 3.5 ''`
Reactor Charae isopropyl alcohol 45 A mixture of the monomers and initiator listed is added to refluxing isopropyl alcohol over a 90-minute period. An additional initiator change - 0.2 parts t-butyl-peroctoate in 5 parts isopropyl alcohol-1071~789 is added 30 minutes after completion of the monomer addition.
The reaction mixture is maintained at reflux an additional 2 hours, cooled to room temperature, neutralized with 90%
of the calculated equivalent weight (based on acid functional comonomer) of dimethylethanolamine, and reduced to 60~ by weight solids with water. The polymer thus prepared has molecular weight (Mn) of about 9,200. The ( glass transition temperature of this polymer is about 18C.
\ Step III Formulation of Paint A mill base is prepared by pebble milling together the following materials:
Components Parts by Weight polymer solution from Step 25,5 titanium dioxide pigment 13.8 Water 3 3 An enamel is then prepared by blending this mill base with the following materials:
Components Parts by Weight latex from Step I 42.5 Water 19.0 iso~ropanol 1.0 propylene glycol 5.1 melamine crossl nking ag~,4.6 "CYMEL" (Trade Mark) 300 10% aqueous dimethylethanolamine 1.4 10% aqueous p-toluenesulfonic acid(2) 3.8 `` 1071789 (1) a product of American Cyanamid Company, and a commercial grade of hexamethoxymethylmelamine, (2) the solution is adjusted to pH 8 by addition of dimethylaminoethanol.
The enamel so obtained is reduced with water to spray viscosity (20 seconds - Ford Cup -No. 4 follows ASTM D-1200), applièd to primed steel panels, i.e., mild steel panels to which has been applied a standard epoxy type automotive primer~, by spraying and cured for 20 minutes at 180C. The cured film has a 20 gloss of 75, determined by ASTM D-523.
This film demonstrates no visible change after soaking in water at 32 C for 240 hours. This film displays excellent solvent resistance. The film flexibility and hardness are suitable for automobile topcoats.

The procedures of Example L are repeated with the following differences: (1) the monomer emulsion of Step I
is prepared from the following reactant monomers and chain transfer agent, all other materials employed in preparing the latex being the same in kind and quantity as in Example 1:

Materials Parts by Weight methyl methacrylate 49.0 methacrylic acid 5.0 ethyl acrylate 16.0 butyl acrylate 30.0 l-octanethiol 0.4 The molecular weight of this polymer (MQ) is about 13,300 and has a glass transition temperature of about 20C.
A paint is formulated according to the procedures - 25 - ~-i of Example 1 using the following components:

' Components Parts by Weight -- .
Mill Pase Let Down latex from Step I -44, O

polymer solution from Step 2 5.5 --titanium dioxide pigment16.5 water - 4.021.0 I 10% aqueous dimethyl-! aminoethanol - 4.0 t isopropyl alcohol - 5.0 ¦ n-butanol - 4 0 Cymel 300(1) - 6.0 (1) defined in Example 1 The resultant paint is adjusted to 25 seconds Ford Cup No. 4 viscosity by addition of water, applied to primed steel panels, and subjected to a twenty-minute bake cycle at temperatures moving upward from 80C to 180C and remaining at 180C lasting for about 10 minutes.
i The procedures of Example 2 are repeated with the single difference that, in the preparation of the emulsion :
is prepared from the following reactant monomers and chain transfer agent, all other materials employed in preparing the latex being the same in kind and quantity ` as in Examples 1 and 2.

Materials Parts by Weight methyl methacrylate 49.0 methacrylic acid 5.0 ethyl acrylate 16.0 butyl acrylate 30.0 l-octanethiol 0.2 :

1~)71789 The molecular weight of this polymer (Mn) is about 17,500 and its Tg is about 20C.

The procedures of Example 2 are.repeated with the single difference that, in the preparation of the emulsion polymer in Step I, there is used 0.1 parts by weight of : l-octanethiol, all other materials employed in preparing the latex being the same in kind and quantity as in Example 2.

The molecular weight of this polymer (Mn) is about 24,000 and its Tg is about 20C.

.
The procedures of Example 2 are repeated with the : difference that, in the preparat~on of the emulsion polymer is Step I, the monomer emulsion is prepared from the following reactant monomers and chain transfer agent, all . . other materials employed in preparing the latex being the same ;~ in kind and quantity as in Examples 1 and 2.

Materials Parts by Weight methyl methacrylate 50.0 methacrylic acid 5.0 `- ethyl acrylate 35.0 butyl acrylate 10.0 l-octanethiol 0.4 ~ The molecular weight of~this polymer (Mn) is about :~ 13,000 and its Tg is about 32C.

The procedures of Example 2 are repeated with the single difference that, in the preparation of the emulsion polymer in Step I, the monomer emulsion is prepared from .;

27 ~ r 1C~71789 the following reactant monomers and chain transfer agent, all other materials employed in preparing the latex being the same in kind and quantity as in Examples 1 and 2.
Materials Parts b~ Weight . :
methyl methacrylate 25.0 ~ t methacrylic acid .7.0 styrene 20.0 butyl methacrylate 30.0 butyl acrylate 18.0 l-octanethiol Q.4 The molecular weight of this polymer (Mn) is about 13,000 and its Tg is about 40C.

A heat-curable coating composition is prepared in the ..
following manner:
Step I Preparation of the~Acrylic Copolymer Latex :
Monomers and AdditivesParts by W~ight styrene 20.0 hydroxypropylmethacrylate18.0 2-ethyl hexyl acrylate . 20.0 butyl methacrylate 30.0 acrylic acid 2.0 methyl methacrylate 10.0 water 90.0 l-octanethiol 0.5 Triton X-200(1) 1.2 Triton X-305( ) 3.6 potassium persulfate 0.4 Reactor Charge Water 60.0 :
' ,~ .

Triton X-200(1) 1.7 potassium persulfate 0.1 (1) defined in Example 1 (2) defined in ~xample 1 The reactor charge is heated quickly to boiling and cooled to 95C. The reactant monomers are mixed with the listed additives and an emulsion is formed by stirring. The monomer emulsion is then added to the hot reactor charge over a two-hour period. The temperature is maintained at about 90C during and for two hours following the addition of the monomer emulsion. The latex is cooled to room temperature, filtered and formulated into a paint as hereinafter described.
This polymer has average molecular weight (Mn) of about 10,000 and a Tg of about 15C.
Step II Preparation of Water-Soluble Acrylic Polymer A water-soluble, acrylic copolymer is prepared from the following materials:
Monomer Mixture and InitiatorParts by Weight styrene 15.0 hydroxypropylmethacrylate 10.0 acrylic acid 8.0 butyl methacrylate 37.0 2-ethyl hexyl acrylate 20.0 methyl methacrylate 10.0 t-butyl perbenzoate 3.0 Reactor Char~e 2(2-butyoxyethoxy) ethanol 43 ~ The reactor charge is heated to 130C under a ; nitrogen atmosphere. The mixture of monomers and initiator is added over a 2.5 hour period. The temperature is mai~ntained at about 13DC during and for 2.5 hours following the monomer ' - 29 -~, ,~, .

`: 1071789 addition. The pol~mer solution obtained is cooled to room temperature, neutralized witl. 90~ of the calculated equivalent weight (based on acid functional comonomer) of ~ dimethylaminoethanol, and reduced to 60~ solids with water.
-:~ This polymer has average molecular weight (Mn) of about 5,000 and its Tg is about 17C.
, :' ' ,, .

:.
, " , .~ 30 ~ .~
: ,; ' s, ., . _ --3~_ ,':~`
,, ~ , 0717t~
`~ i Step III Formulation of Paint 2 A mill base is prepared by ball milling the 3 following materials:

4 Materlals Parts by Weight Polymer from Step II 76.5 Titanium dioxide pigment 180,5 7 Water 40, 8 An enamel is formulated by blending this mill base 9 with the following materials.
-Materials Parts by Weight Cymel 301(l) 69.5 ~ 12 n-butanol 55,5 ë;~ ,13~ 2(2-butoxyethoxy)ethanol 20,8 14 ~ latex from Step I ~ 382,0 15~ 10~ aqueous dimethylaminoethanol41-7 ~ 16 Water 133.5 y,; ,`~ 17 ~ (l) a commercial grade of hexamethoxymethylmelamlne 18 marketed by American Cyanamid Company, 19 The paint so obtained is reduced with water to spray ,20 - viscosity (17 seconds, Ford Cup No, 4) applied to primed steel 21 panels and subjected to a 30-minute bake cycle comprising ten 22~ minutes during which the temperature rises from 80 to 160C, duri g~
23 the first 10 minutes and remains at 160C, for lO minutes, The 24 ~ cured film has a 20 gloss of 80, is unaffected by xylene (one ~25 minute exposure), or by exposure to water at 32C, for 240 hours, - ~ ~ 26 ~ EXAMPLE 8 27 The procedures of Example 7 are repeated with the 28 single difference that, in the preparation of the emulsion polymer 29 in Step I, the monomer emulsiorl is prepared from the following reactant monomers and chain transfer agent, all other materials 31 employed in preparing the latex being the same in kind and quantit as in Examples 1 and 2, ,- ,',, ' ', ~

, . . ~

M~ 1071789 rQrt: by Wel~ht 2 ~,tyr(~n(~ 20.0 3 ,' methacryllc nci.(l . 15.0 4 i butyl llcryl.atc 55.o ¦ butyl meth~crylat~ 10.0 1 6 ¦ 2-a¢rylamide - 2 - methylpropane ~ulfonlc acld 1.0 ~7 ¦ l-octanethlol - 0.7 .' 8 : ¦ Thi~ polymer has average molecular wei~ht -9 ¦ (~n) Or about 8,000 and a q'g o~ about -5C. '~
~;, ., ., l .
. 10 I EXAMPJJE 9 !' A heat-curable coating ¢omposition ls prepared ; :~
. 12 . ¦ ln the rollowing manner. ! ~
'; , ~ I i 1.. .':.', 13 Step I Preparatlon Or Acryllc Co~olymer Latex i ~
. `' , . . ', .
14 Monomer~ and_Addltives Parts by Wei~ht i;
:: 15: methyl methacrylate 48.0 ...... ~-.. !,'i~
.~, 16 ; . methacryllc acid ; : ~ ~ 7.o ~ ~
:.. 17 ethyl acrylate ~ 35,0 ` , . `.
"18 . butyl acrylate ~ io. o ~i;
~:`' 19. .- l-octanethlol . , . ;~ 0.4 ; `' ~, 0`~1 Trlton X-200(~ 1.,0 ~ '` ~.
. 21 r ton X 305 . . .. 4.5 . ~ .
.22. Water , amm,onlum per~ul~ate ~ . . 0~4 ~ ;;. ,:~

. . ~ , , " , ;~ . , 1 4l Reactor Char~e ; `. ~ , ~
25 ~ Water 30 ~ l~q~ t ~, 26: i Triton X-200(1) ;2~ i $
'27 ~ am,monium persulfate 0,1 .~ :

, ~ . ~ ;
I ~ ...... :
~ - 32 _ . .

lll 1071789 Ij (l) (~crinc(l irl ExarnF)le 1, 2 ¦ (~) de`1rle(l in Example l 3 ¦ ~he procedure3 of Step I, Example 1, are repeated 4 ¦ to produce a latcx of 40% ~ollds. Thls polymer ha~
¦ average (Mn) o~ about 13,000 and a Tg of about 32C.

` 6 ` ¦ Step II Preparation o~ Water Soluble Acryllc Polymer .:~
~he procedures o~ Step II, Example 7 are duplloated, .:8 ¦ Step III Formulatlon oP Palnt 9 ~ ; ¦ A mlll base ls prepared by pebble milllng together ;~ io ~ !' ¦ ' the ~ollowlng matorlals: . . :~
, , ' . I . ' ' ~ . ,. ' .,'' ~ I :~ ; .";:'t ; il I Materlals Parts by Wel~t . . I ;, ,,,, ,1 12 ~ ¦ polymer solutlon o~ Step II : . ll.0~ . ,{'~i ~, 13 ~: ¦ Cymel 300(1) ; 8 0~ ;`1,~.
14.,, ¦ tltanium dloxide plgment 19.7 .,,; ~.;j;,~!
~ 15 ~. ;l~opropanol ; ~ , . . ~i~
; . 16 n-butanol : . 5,o - ,n`
17 Water :: 6.0 ~:, . , , 18 . (l) def'ln~!d ln Example 1,;~ '' ~ . .',', `~`:!', '~

; i9 ii An enamel 1~ prepared by blending thl~ mlll base : ~ ~20; ~ wtth the f'ollowing materlal~
! ~ ' i ., , , . " 1 ' !
. 21 . ~atorlal~ Part9 by Wel~t `~ .
;~` 22 latex ~rom Step I 55.o.'.;~ '~;
'23 ' 10% aqusoui~ dlmethyl~thanolamlne 4.0~ t~, ,;r.l :24 Water 13.0 ~It, 10~ aqueous p-toluenl~ ~ulfonlc ., . .; !, ? 3:
26 acld (neutralized wilih ,~ .
27 dimethylethanol amlne) 0.6; ~, - 33 - ~
. . ,., `" ' 10'71789 `~ _XAMl'r,h ~10 2 l~ T~le proce(~ur~; Or Exaimple 1 are repcat~ with 3 j the ~;ln~rle dirferenc~ t~lat in th~ pre~ ratlon of the 4 soluble polymer o~ St~p II 2.5 part3 t-butylperberlzoate are u~ed ln lieu of 3.5 part3 Or t-butylp~roctoat~. The 6 polymer ~o obtalned has average molecular welght (M ) 7 o~ about 10,500, ~ ~ ;~'-'.-" : ~ . ~ '. ~
' ~ 8 EXAMPLE 11 The procedures o~ Example 7 are repeated with ~
~ the ~lngle dl~erence that ln the preparatlon of the ;
i il ~oluble polymer o~ Step II, 3 part~ t-butylpero¢toate are used ~, 12 ~ ln lieu o~ 3 parts t-butyl perbenzoate. The polymer i 13 thu~ obtained ha~ an average molecular welght (Mn) of ;
14 about 6,000. ~
.. ',, ., . , , ' ' ~' .'." ,''i'~' 15 ;~; EXAMPLE 12 16 ~he procedures of Example 9 are repeated wlth :~
17 the dlfference that the water soluble re~ln of Step II ~ ;;
~; 18 ~ ls prepared ~rom the frollowing materials: , ~ ;
,., ' ~' " ,'`, ,,~
19 Reactant Monomers and Initiator ; ~ ~ Parts bY Wei~ ;
~' 20 ; hydroxypropyl methacry~ate ~ 10 ~ i ~
' ~ !,,,,.'~ 21 ~ aarylio a~ld ~ 8 ~ "
;!, '. 22, ,.~,, ,~ styrene ~ 25 - ~ , ;
~,;` 23 2-ethylhexylacryl~te ! ~ 26 ~ , ~ , ;~
24 butyl methacrylate ;~?6 ~ i ~pr ,' ;25 t-butylperbenzoate , 3 ,~
, ~ "I,i ~
26 Reactor Char~ '~
27 2-butoxyethanol 43 ` ir't` `;~
2~ The polymerlzation 1~ carried out at temperatures i~
29 between 120 an~ 135C. The polymer has an av~ra¢~ ~ ~, molecular weight (Mn3 of about 6,ooo. _ `` ~ 1071789 .X M~
2 jl ~rh~ pr~ce~ r~ Of~ Examp].e :L2 .ar~! rep~ated wlth the 3 I di~ference that 5 part'3 of Rcrylonitril~ are ~ubatltuted 4 I ~or 5 parts of atyrene.
I ' ,.'~ "~"
. . 5 ¦ . EXAMPLE 14 ;; ~.
. . 6 ~ ¦ The procedure~i of Example 7 are repeated with the : ;
7 ¦ dl~erence that the water 901uble re~ln 1B prepared ~ ~ ~ :"
~::j' 8 ~rom:
. : :,., ,~
;` ~!'~' g Monomer ~eactant~ and_Inltlator partB b~ lght 0 ' methyl methacrylate 50 ~, ., ethyl acrylate ~ 42', . ~ .
; 12~j . methacryllc acld ~ ~ ; ;8 : . :
: 13 . 5-butyl peroctoate . 3.5 ~ "

,, 14 : Reactor Char~e ~ 1, isopropanol 45 ~ ~

, 16 ~he polymerlzation i9 carrled out at reflux -.`. ~., ' 17 ~ollowlng the procedures of Step II of Example 1. . ....
. ,18~;;:.; The average molecular wei~ht (~n) o~ thl~ polymer ; ~ .
j."~ r~ ls about 9jO00, l ~ ~ , . .

.. .~ . ~ ., I :;, : , .,, . . . . . i . ' :;: , ..
~ ~ ` EXAMPLE 15 ~ `
.~ ~ The pro¢edure~ of Example 7 are repeatèd with ;
22 ~ the dl~ference that the water 901uble re91n iB prepared ~ rS r,~
,. '~''`'t; ~ 23-~ ~rom the ~ollowlng materlals~ .

~ ~ 35 ~
. '.~``,',`;'''i !i ;

! .
1 071 78~

,i 1 i~ Monomf?r Rr?ncl;nnt:~ antl Initl.ltor E~art~_by Welght 2 ¦ meth~crylit aci~ 18 3 I butyl acrylate 55 4 methyl methacrylate 27 AI~N(l) 3 :
. " ~ .., . 6 Reactor Charge : 7 l~opropnaol 45 ;~'. ' . : '~.'`' (1) 2,2~ - Aæobiai - (2-methylproplonltrile) .,, , , . . . :;,: .
9 The polymerization 19 carried out at reflux ~'ollowing the procedures Or Step II o~' Example 1. The . .
,'11 polymer 80 obtalned has ~verage molecular wei,~ht Or ~bout . .
12 5,000 and a Tg of 2C~ ; ,.
.', ': . ~
; ;. ~3 EXAMPLE 16 . ~ .
,~,. 14. The procedure,~ o~ Example 15 are repeated with the ~ dl~rerence that the 301uble resin i~ prepared rrom the ~ ' ~!
, ~ . - ' ~
~ i6 : ~ollowln,~ materlals~

. . ~ ~
;it;;i,,.;17.. ~ Monomer Reactant~ and Inltiator ~ ~
. ," hydroxypropyl methacrylate . . 10 ~ P~lii 19; methaoryllo acld 10 ~ ~!
. ' ~ ~, I
r~ 20 ) ~ butyl aorylate : ~ . 55~ .; ! - ;
~21~ .~ ;methyl methaorylate;~ " 2 5 t ! ~ ;~ :~
m~22:~ l :AIBN ~ 4 ~ i ~ 23 ReQctor Char~e ~ Y~ ~l' i'l'~.'X
: . ~ ;.`` t ~ 5~ . 'h~ 24 lsoprop~nol . 4 ,S ` ; j'~, ! . ' ~ ~ ~
The polymer thus obt~lned has avera~e mol~atcul~r . ... ~; st' ~t6 welght (~n) ~ about 4,000 and lts Tg la ~bout -1C. . ............... .:

- 36 _ .
l!
` _ `

The procedures of Example 15 are repeated with the difference that the water soluble resin is prepared from:
Monomer Reactants and Initiator Parts by Weight hydroxypropylmethacrylate 5 methacrylic acid 10 N-methylolacrylamide 3 methyl methacrylate 37 butyl acrylate , 30 butyl methacrylate 20 t-butyl peroctoate 3 Reactor Charge isopropanol 45 The procedures of Example 1 are repeated with the difference that the ratio of polymer obtained from the latex of Step I to that of the solution polymer of Step II is varied as follows:

. .
Polymer Parts by Weight A B C D E F
~` -polymer from latex 92 85 75 65 50 35 polymer from solution 8 15 25 35 50 65 Coatings B, C, and D display acceptable gloss (~qual to or greater than 70 at 20C) and appearance, and are nearly equivalent in terms of tendency to sag and run during spray application. Coating A is marginally accep-table, it displays lower gloss (65-70 at 20). Coatings E and F are inferior to coatings B-D; they. have excellent gloss, but display a greater tendency to sag during spray ,. . .
application, and considerably more solvent popping during cure at a given wet film thickness than do coating A-D.

The procedures of Example 1 are repeated with the differences that the formulation of paint is as follows:

; Mill Base Parts by Weight . polymer solution from Step II 5.5 ... ~ titanium dioxide pigment 13.8 ; Water 3-3 Other Components ,.~ ~ . .
latex from Step I 42.5 -~ Water 20.0 -- 20 isopropanol 1.3 .~ n-butanol 5.0 ~,, ! "RESIMENE" (Trade Mark) X-735(1) 7.2 ".
~ 10~ aqueous dimethylethanolamine 1.4 :.~ (1) A product of Monaanto Company and a water : reducible methylated melamine resin supplied at 80 . solids in isopropanol.
.,:

~.i ~ ' ' ~ "' ' ' ` 1071'789 '.'' 1 !, Thi~ ~n~m~ cur~d b,Y b~kirl~ at 140C ~or 2 ¦ 20 mlnut~.

3 In th~ precedlng 19 examples, the water-based 4 palnt ha~ been formulated ~rom an amino re~ln cros~-S llnklng agent, a synthetlc polymer latex and a ; ~ 6 polymer ~oluble ln the aqueou~ pha~e wlth the latter 7 prepared by ~olutlon polymerization ln an alcohol or slmllar ~; 8 water dllutable organlc 301vent. All ~uch paints retaln ~; 9 some of thl~ solvent.
In the elght example~ lmmediately followlng, .
11 both the solution re~ln and the emul~lon resln are ~ 12 prepared by emul3ion polymerization. The paints thu~
; 13 prepared are free Or organlc golvent unle~3 ~uch solvent ;
~ ; i~ dellbèrately added.

lS ~ : EXAMPLE 20 ~ : ~ :, ,~ ", . ~ , . "

16 Step I Preparatlon o~ the Solutlon Polymer 17 An acryllc copolymer 301uble ln the aqueou~
lB phase o~ the water-ba~ed palnt of whlch lt later ~ , 19 become~ a part l~iprepared ~rom the ~ollowlng materlal~ l ;'20 ln the manner herelna~ter de~cribed~ ~ ~

lal~ Part~ by W~l~hO~ ~ .i 22 methyl methacrylate ~ ~ ~ 45.0 j, 23 metha¢ryllc acid 15,0 ~ ~ t,i~
2~ butylacrylate ; 40,0 ~ ; ~;~
Water 9. `~ h' '``"!
26 ~rlton X-200(1) 1.15 27 Trlton X-305 ) 3.58 ~; ,i ; 39_ _ . ~ ~

- ~071789 l pota~ m ~rnlulr~lt(~ 0,4 2 , l-octanethlol 1,5 ! ~ ~
3 I Reactor Char~e 4 ¦ Water 60,0 60,0 ¦ Trlton X-200(l) 1.67 potassium per~ulfate 0.1 ', ' I . ' ,' 7¦ (l) deflned ln Example l.
8I (2) de~lned ln Example 2.
. . l :' ~- 9¦ The rea¢tor char~e i~ heated quickly to bolllng ; 10 ¦ and aooled to 95C. A monomer emul~lon 1~ rormed :
; 11 ¦ from the above by~mixlng and ~tlrring. The monomer ~;
; 12 emulsion i~ added to the hot reactor charge over a 13 two-hour perlod. The temperature l,ci malntalned at 90 ~, ,;
14 + 5C throughout the monomer addltlon perlod and for two ` ; 15 ~ hours a~ter addltlon 19 complete. The 2-(dlmethylamlno) ; ~
16 sthanol lc added ln an amount equlvalent to the acld ~/ ;:
; monomer incorporated ln the polymer and the sollds ~
~ 18 oontent lc reduced wlth water to 30% by welght. ~he ?i, ; i19 ,~ polymer (~n) l~ about 5,000 and the Tg 1~ calculated ~
20; to be 25C. ~ ~ .

21 ~ Step II Preparatlon of the Emul310n Pol~mer ~ ~ `
~ 22 ~ - An emulslon polymer i~ prepared ~ollowin~ the ;; ' ;;~
; 23 procedure o~ Step I ~rom the ~ollowlng rea¢tant monomers ~ i, ' ,~ 24~; and chaln tran~fer a¢ent, all other materlal8 employed ' ;,!
ln prepar~ng thl~ latex belng the same in klnd and ; "~
quaneley ln ~a~ple 1. ~ ¦

l . .

~ 1. M~lt,_ria~ nrt~. by Wei.~ht 2 I m~h~. met~acrylate 48.0 3 ~ methacrylic acid 7 0 4 ¦ ethyl acrylat~ 3~.0 .
¦ butyl acrylatc lO.0 6 . ¦ l-octanethiol 0.4 l .
~ 7 ¦ The average molecular ~elght of this copolymer ; :. 8 ¦ 19 about lO,000 and lt has a Tg of about 40C. , ,' '`'''' ~' I ' ' , ' . '' : 9 ¦ Step III Formulatlon of Palnt tfree of organlc ~olvent) . lO : ¦ A mlll base ls prepared by pebble mllling together . l .; :-11 ~ ¦ the ~ollowlng materl~ls: ,; .

'.,, ' ' I . ;' .
; 12 Materlals ` Parts by Welght ; 13 polymer 901utlon from Step I 18,4 .
14 Cyme~ 300(1) 6.7 .
;15 titanlum dloxide pigment 16, 5 . .;;
,l , 16 Wster . 8.3 ~;!!

.`" l7.~ (l) de~lned ln Example 1. , : '.`5 ' ' . . ,, , ~ ~ .

:~ ~ ia An enamel ls ~ormulated by blendlng together , , ;,j the followlng materlal~ ;~
,,, ;, , .' ,,. ,~
~ 0. , Materlal~ , c ~ .; .,, : ~ 21 latex ~ro~ Step II 46.o , i ~; 22 lO~ aqueous 2-(dlmethylRmlno)ethanol 3.3 ~ l~
23 10% aqu~ous p-toluene sul~onic acld ~ i' ~7`~, .,,: 2~ ~neutralized wlth 2-(dlmethylamino) ~' . 25 ethanol) 0.8 ~' 26 mlll base 49.9 ; . ,~. ;~
.. ~. i; ' '! ~! `
27 The vlscoslty 0~ the palnt 13 ad~usted to , .
28 17-20 seconds ~No. 4 Ford Cup), and 9prayed on , :~
~ . :.
~ ,'. , ~

:

' 1071789 1 primed steel E)arlel3. 'rhe panel~ are balced 25 minutes, 2 The b~kin~ temp~!ratur~ at th~ b~lJinnir~ 80C.
3 Thi3 13 lncreas~d gradul].]y to 180C an~l malntained 4 ~ at 180C over a ten-minute perlod. The resultant panels have a coatlng of excellent glo~s and organic 6 solvent re~i~tance (one mlnute xylene expo~ure). Appearance 7 and hardne~s do not notlceably change when water 30aked ."
8 . at 32C. '~!
,',''~ . "i' :: g EXAMPLE 21 :
~0- The procedures of Example 20 are repeated with ;
.~ 11 the followlng difference3: (1) the reactant monomers ~ .~ ;
12~ and the ohaln trans~er agent used ln the monomer emul~lon : ;
13 o~ Step II are as follows: . ~ .
,,'''~ "''' , '' :' . ~ '"', ":~
,.-,. , 14 Reactant Monomers and Chain Parts b~ Welght . 15 Transfer A~ent : ~,' .'. .,`. ~, ' ~, . ~ . ~:
; 16 methyl methacrylate . . 49.0 ;, .
': 17 .- methaorylic acld . 5.0 / . j,.
18 butyl acrylàte ; ; ~ 30.0 ~:~Q
., . ...... ~ethyl acrylate : : ~ . 16.0 , ,.; l-octanethiol ~ ~ 0.1 ; -21 . ,,i : and ( 2 ) the reactor charge l~ heated up to 55 + - :~, .;22 5C wlth nitro~en purglng~ The emulslfled monomer~ ;t ~ 23 ; are 8dded for a perlod of ~our hour~. Reaotlon i9 . ` ;` , ~ . `'~
., 24 : contlnued for another two hours wlth the temperature ~ ; ,'r ; ,~`.25 ~ -maintalned at 55 + 5C, ~he latex t,hus obtalned 1~ "';.
f'~',2 ~ ' ~ ' ¢ooled, rlltered, and used ln the ~ormulation o~ a ` ~,r,,"~,l ! ;
2r ~at~r-b~ed enamel as ln Example 20. ;`~ .
,-''' ' ~ ' ' ' ' '"'.; ''''''`''`' t~

2a EXAMPLE_22 .~ . ,~
29 A series of water dllutable polymers are :, ` .:/.
prepared a~ ln Step I of Example 20 and employed in place: . ~
31 ~ the water dllutable polymer o~ Step I, Example 20 -.

... ........ ~ ~8 ,:: . . ~

` 107~789 in the water-based paint descri}:)ed in Example 20. The procedures of preparation are the same as used in Step I
of Example 20. The materials employed in preparing these "solution polymers" and the molecular weights and glass transition temperatures of the resultant copolymers are set forth below:
Materials Polymer Designation A B C D E
:: styrene 25 methyl methacrylate 50 45 35 35 methacrylic acid 1015 15 15 15 butyl acrylate 3025 40 50 50 . ethyl acrylate 10 butyl methacrylate 35 Triton X-200 2.8 2.8 Triton X-305 3.63.6 3.6 3.6 3.6 .
"AEROSOL 22" (Trademark)( ~ 2.4 2.4 2.4 l-octanethiol 11.5 2 1.5 Properties of Polymer (Mn) 75005400 4000 5400 7500 Tg, C -8 16 25 8 8 (1) Aerosol 22 is a product of American Cyanamid Company A series of emulsion polymers are prepared as in Step II of Example 20 and employed in place of the emulsion polymer of Step II, Example 20. The procedures are the same as used in Step II of Example 20. The materials employed in preparing these "emulsion polymers" and the molecular weights and glass transition temperatures of the resultant copolymers are set :forth in the following Table:

B

1 107~L789 j o~
' ( ) ~ r~l ~ o O O
. ~ ~_~ Lr~ r-l W
t_ O\ ~
c ) I~ Lr~ o ,~ ) o o U~
1~ N r l U~ r~ O
O
. a~ r~
., o (~ O 0 0~ ~ ~ O O ~ .
~1 N N Lr~ r~ r-l O ~
.- Ot~ ,' ~: æ O u~ u~ o ~ ~ o O u~
: -: . ~ ~ ~ 0 1 ~ :' .''. ' ~ . .~ . . .
H O~
.; . U~ O ~1 0 t~ O O ~I ' " ~ r ~ j N ~ ~ ~ OD : :
'' `',.,~i:"','~ . ~ ' O~ `' ' ' ::
., ~ . . ~ O , t~ 1 ~ ,., ' ' , , . . 1 ~ t~ 1 O t~ . ' . ! .
" O . 3~ .
. ~ .,";1 : Ir~ O O OC) ~ N O . ~ O ~-- ;;
,' ; . ~) ~J ~ N S
, ~ , . . ~ . ' ! ~ ; J, ,'`''';'~;',.',' " ~ ' . . , , . ~D J ' 'I ':'~ ~''''' :, ,';, ' ' . U~ O 11-~ ~ ~ 1'-1 0 ~ '~
n '"~i ' ' t~ `.' '~ ' ' U~ '. ':' . ' . . ~ o Lr~ n ~ o , . o r l , , ~. ~ , U'\

~ ~ ' ' , , ' ' : ~ ~
. ~ . :

:",.. ,.;. ~ . H ' J~ r ~ H ~ .

. ~ t.) ~ O -~ , ~ ,~ ' ~ ' '; . , ~ ., ~ d tl\ ~ . ~
h ~ h r-t c- ~ f-~ ' ' ~
,L t.) -~ H td ~ a o o ~r~ , J 3 ~r I t~r~ S O ~r ~ t~J tn t~ ' ., r~ f ~ r, ' ~ C X' r H t ) ~r~ , rl ~ r- I ~
~) ;~ tl~ H r~l r--l O h 0 0 u~ I ~ O
h .r~ ,t1 ~" ~ r~ h t~ O t~
a ~ ~ ~r I h O ~
tl~ h (11 1 ~ bD
t" ~ ~ ~ m ~ ~ t~ c~ rl l ~

I`
~071789 I~:XAMl'~ 2l!
2 ! W;ltl~r-ba .( (1 ~rl Im~!:L i pr~ red by m1 x:l nfr .;, 3 ; the rollowirl~ mat(?r:lalEl: ~

: 4 Materlals . Parts b~ Wel~ht Mill Ba~e (prepared by .
": 6 pebble mllling) :
.7 polymer (~olution polymer) , '' . 8 ,, ~rom Step I, Example 20 lB~8 , :
: : Cymel 300(1) 4.6 ~,.
; 10 titanium dioxide plgment 16.9 ~:
11. , ~Water '7.3 .
""':' ~ .
., ~ ', 12 .~ , (1) de~lned ln Example 1.
':

. .
~ ; !, ' 13 ' Other Materlal~ (to let down) , ' . ,~' ". 14 polymer (emul~lon polymer from ,, ,- ';
',': 15 Example ~1 47.0 , '~ '! ;' ; 16 10% aqueous 2(dlmethylamino)ethanol 4.4 , :",. !
I ," 17 10% aqueous p-toluene ~ulfonic acld . ., ., 18:. (neutralized wlth 2-~dlmethylamino) . ., , .
; 19 , ethanol 1.0 ,. t !
. .;~"20 The above enamel i~ sprayed on prlmed ~teel, ~ ', ~,' ~,',,;21, panels and baked ~or 25 mlnute~, The initlal -............ -."~
,''- 22, temperature o~ the bake 1~ 80C and thls 1R ralsed ~ , .~
:;l,i';23 . , gradually to 180C where the latter temperature 1B , ~ 'r 24 ! , malntained for 10 mlnutes, The appearance o~ the ; ;~ '; ':^
`' 25 baked panel and the propertles of the baked ¢oatlng .,' . ~ ... ', ."
.,.,. , ~ ; i,~
... :' 26,; are e~entlally the ~ame Q9 tho~e obtalned in Example , ~ ;~i, , 20. , ~ ", 2~ ~. EXAMPLE 25 . ~ ',,, ~, , A water-ba~ed enamel 18 prepared by mixing ~ ~? '~1,`
3 . the followlng materlals~ , `:
_ 45 _ : '~
. ,' . .

'1071789 1I Mlll l3~ )ri~ lr~d hy bnll mllll~_ Part~. b~ Weight 2 ~ polytTI~r "D" o~ Example 22 (,~301uti~n 3 I polymer) 18,5 4 Cymel 301 7.6 S tltanium dioxide plgment 16.5 ,;
Water 8.4 ;
, .: . ' . , . ;`'.

7 Other Materlals (to let down) 8 polymer ~ai~ of Example 23 (emulsion i 9 polymer 46.1 10% aqueou9 2-(dimethylamino)ethanol 2.9 -''',; ' ~ '.''"'.;. .
11 (1) a product of Amerlcan Cyanamld Company, 12 and a commercial grade of hexamethoxymethylmelamlne. ;~ ~ "
,': : ;. .~
13 This enamel is ad~usted to a ~lsco~lty of 17- ~
14 ~0 seconds (No. 4 Ford Cup), by addlng water and '~;
15~ sprayed over primed steel panels. The ¢oated steel i6 panels are baked at 160C ror 25 mlnutes. The baked 17 coatlngs exhiblt good gloss, good ~olvent reslstanoie ~
and retained thelr glos9 and hardnes~ a~ter soaklng , ;,,', 19 ln water at 320 ~or 240 hour~

; ~; EXAMPLE 26 ; ' ~ ' ~`
21 '~l A water-based enamel is prepared by mlxlng ~ ,;
22~ th- ~ollowln,g materlals~

23 ;;~ ~~lll Base (prePared by ball mlllin ~ ! Part~3~L~/Cl~e~ ,!
24Polymer "A~l o~ Ex~mple 22 (solution , ~ ' Cymel 300( ~;14-8 '~

27 tltanlum dloxlde pigment 17.7 28 Water 9 ~ ~, : ~ ` . I A
- 46 - i~
.~

1071'789 .-l I Other M.-lterlal.3 (to l~t- (lown) , : 2 j polymer "A" of Example ~'3 (~mu].;ion 3 polymer) 49 4 4 10% aqueous 2(dlmethylamlno)ethanol 3.6 10% aqueous p-toluene sulfonlc acid ll :;
~, . .......

. 6 (1) derlned ln Example 1. .. .
. -' . ': .: , ' '., '' - ; 7 Thls enamel ls ad~usted to a vi~icoslty o~ 20 a - seconds (No. 4 Ford Cup) by addlng water, and . .:
. sprayed o~er prlmed steel panels. The~ie coatings are baked for 25 mlnutes. The inltlal baking temperaturs ~ . :;
; i9 80C and thls is gradually raised to 180C where ; ~ ~
: 12 lt ls malntained rOr at least 10 minute~i. These 1.
. . . . ;. ,. ., 3 coatin~s exhlblt good physlcal propertle~,, - ;
;" ,, 1,' ,,,, ,~ ,, ' ' i l ' . ,'' `" ,."
'~ ; EXAMPLE 27 . ~ ;
.~ 15 ~ A water-based enamel ls prepared by mlxing ~ i ;, ~16 . . the following materlals: - : - ;
. . . :,'' .. : '., . 17 ~ : Mlll Ba,~,e (~reiared b~_ball mllllng~ Part~, by Welght :
Polymer "B" o~ Example 22 (solutlon .
l9 ~ ` polymer . 12.4 ::~` `;;
,, . 20 ~ ; t~tanlum dloxlde pi,gment . ;16.3 .
.,, ~ . ~ . ~
s 2l ` Cymel 301 ` ' . ~ . ~;` 8.3 . ~ :;
; 22 ! ~ Water ~ . 8.3 , ,~ . '~~

23 (l) derlned ln Example 25 . ~; ~ "~ .L.;

~ " . ~ .? . i ~
~; 24; Other Materlals (to iin~t~ ; - ! ri, ; . 5 Polymer "I" of Example 23 (emulslon . ~ ~i~26 polymer) 45.6 27 ¦¦ lO~ 2-( ethylamlno)ethanol 9 ,.,' .., 1,', i, I T~ 3 ~nam(?l ii~ adJu~,tecl to a vi sc09ity of 20 ,~, 2 aecond~ (No, 4 l~'orà Cup) by ad~ing wal;cr and ~prayed 3 on primeid steel panel~. The coated paneil3 are baked ,~ ~ 4 ~ at 160C ~or 25 mlnute~. the coatings thus obtained , ;~
,, ~ S , exhiblt excellent glo89 80 at 20 and good solvent 6 reslstance, 7 , The followlng examples lllustrQte method ~ ; ~' ~, 8, ~ embodlment3 wherein the palnts of thls invention "l ,' ,, 9 are prepared by substltutlng for the ~urfactant used ln the , ` 10, preceding examples a stablllæer polymer i9 a ' ,,;, solution polymer, i.e., a polymer that,is soluble in the -; ' ,:'12'''"~' aqueous pha3e of the water-based palnt. As afore~ ; ' '"'~
, 13 ,,~ , mentloned, this stabllizer polymer may be the same "
14 ; as the solutlon polymer which 15 a prlmary constituent '~
~, 15 of the paint or lt may di~er therefrom 90 long as lt ~ ~
16 ~; 1B ¢rosslinkable wlth another polymer or crosslinking , ,~, 17 agent ln the system and 1~ otherwii~e compatlble wlth ,, ", ,! ;
18 ~ ' the system. '~'he average molecular weight of the - ' ; ~i~
19 ~ - 3tablllzer'polymer may be the same as that Or the ' , ~, ~ ~;
~'!'`;20'',~ - prlmary solution polymer but pre~erably has lower ', ;', i,~'` ~",'!~
21 ~'' , moleicular welght and most pre~erably has avera~e " ' , ;';` ,1'",', 22 ~'','~ '~molecule welght (Mn) ln the range of about 3jO00 'to ' " ,"
~i Z3 ~about 8,000. The 9tabillzer polymer wll~ ordin~rlly ;:'~'; 'j,''.~"'~
',,t. ,24,.',!~,`, ,1 ' be present ln an amount ln the range o~ about 0.5 to ` ~ ,,, ,~"!/~
"' 25'' 'about 10 welght percent o~ the comblned welghts o~ ` ' 26 ';, emul~lon polymerlzed polymers ln the paint. '~ , ,, '-~` 2t ' ; ~ EXAMPLE ? 8 ; ~ ~
28'', '' ' ~ A water-based palnt ls prepared rrom the ; ','!',,~ ;,h .
,, ~ollowlng materlal~ , 30Step I PreParation, 0~ Q~tabllizer Polymer ,, , t~31There 19 charQ~ed to a reactor ~00 parts o~ water.
32The reactor charge ls heated to boillng and then cooled ~ --- 48 -- lt~ltr~t~

to 95C. To the reactor charge is added Solution A, a solution of 0.1 parts of ammonium persulfate in 0.8 parts of water. A solution, hereinafter termed Solution B, is prepared from 0.4 parts of ammonium persulfate in 2.5 parts water. A reactant monomer and chain transfer agent mixture is formed from the following materials:

Materials Parts by Weight methyl methacrylate 35 methacrylic acid 15 butyl acrylate 50 l-octanethiol 2 The monomer mixture and Solution B are simultaneously ~charged to the reactor by incremental addition o~er a two-hour period. The temperature of the reaction mixture is maintained for 3 hours after addition of the last of the reactants. The latex so obtained is cooled to room temperature and filtered. The polymer thus obtained, hereinafter termed stabilizer polymer I, is thcn neutralized with 2-(dimcthylamino) ethanol in an amount equivalent to the acid monomer content of the polymer. A clear solution is obtained.

Step II Preparation of Emulsion Polymer An emulsion polymer is produced by first preparing the following: (1) there is charged to the reactor 200 parts of water and 4.25 parts of the stabilizer polymer from Step I; (2) the following materials are thoroughly mixed:

: ': 1071~89 , i`
Materia~s Plrts by Wei~ht 2 ¦l styrene 20.0 .
3 I .methacrylic acld 15.0 ~ 4 ¦ butyl acrylate 55.0 J,~ 5 butyl methacrylate 10.0 ~ 6 l-octanethiol o.6 .
.
7 : (3) there are dissolved ln 0.5 parts of ammonium 8 ~' persul~ate and one part of 2-acrylamide-2-methyl-propanesulfonic acld in 2.5 parts of water; and (4) .
10 ~ there ls dlssolved 0.2 parts of ammonium persulfate .
11 ln 5 parts Or WQter. After these are prepared .
:. 12 ¦ the emulsion polymer is prepared using the procedure .
13 and condltions used to prepare the stabilizer polymer 14 Or Step I. In such, the order of addition of the 15 :~ four above listed components is as follows: (4) is .16 ~ added to (1) in the reactor and (2) and (3) are 17~; added simultaneousIy to the mixture of (1) and (4).
. -;18 : Step III Preparation of the Solution Polymer .
19: ~ ~he procedures and steps of Step II of this example are repeated wlth the following employment of ~ ;21 reactant monomers:

; 22 Materials Parts by Weight 23 rnethyl methacrylate 35 24 methacrylic acld .r 15 butyl acrylate 5o 26 l-octanethlol 27 After this latex is cooled and flltered, it 2~ is neutrali~.ed with 2-(dimethylamino)ethano] to t~e ~ 50 -', 1071789 1 ~ ~mount ~(luivnl(~rl~; t-~ t~ mo~ ry]ic nckl c-)rl::tltuent 2 ¦i Or the polymer.

Step IV Prcp.lration of the Or~r,arllc Solvent-Free, 34 Surfac~ant-Free llybrld Water-Bai~3ed Enamel ., ~ , Materlals Part3 b~
6 solutlon polymer from Step III 14.1 ;i ~` Cymel 300 -;`,; 8 tltar.lum dloxlde 16.1 ; Water 6.4 . ' ., ., ,.
; 10 ~ The aboYe materlals are ball millcd ~or ~ ; ,il 16 hours and mlxed (let down) wlth the ~ollowing i ~ ' " ',1!'1 .,ii ~, 12 materia~D: ~ ; ~:
.', " ', .. ,,",. ' '~ -' ~
~ 3 ;~ Materlals Parts by Welght i~ 4i~latex ~rom ~itep II (lncludes both emulslon polymer and , ,~
16stabilizer polymer I) ~ 47~3 - , 1710% aqueous 2-(dlmethylamino) I - ` ; , 18 ethanol 9.6 19 ;~ The enamel thus prepared ls ad~usted to a "` 20 vlsco~ity o~ 17-20 ~econd3 (No. 4 Ford Cup) by , ~, 21 ~; addlng water. It ls sprayed on prlmed steel ` ~ ~, ;i~
~1~ 22~; panels and baked for 25 minutes at 160C. ~he ;~
23 , ooatings thus obtained exhibit good appearance, - ; ` ' ;~
~i ~24 ;~ ~ ~109~ and ~olvent resistance. ~ ii i,~, ' 25 ~ :, ; 26 A w~ter-bQsed enamel is prepared in ~rom the .
Z7 ~ollowing materials: ~C;' - 51 - 'i. ''~
, ;,, ., . ' __ 107~'789 Step I Preparation of Latex (includes stabilizer) polymer and emu sion polymer) (1) There is charged to a reactor 127 parts of water and two parts of the stabilizer polymer prepared in Step I of Example 28.
(2) The following reactant monomers and chain transfer agent are thoroughly mixed.

Materials Parts by Welght styrene 20.0 hydroxypropyl methacrylate 14.0 methacrylic acid 6.0 bùtyl acrylate 30.0 butyl methacrylate 30.0 l-octanethiol 0.6 (3) There is dissolved 0.5 parts of ammonium persulfate in 16.7 parts of water.
(4) There is dissolved 0.1 parts of ammonium persulfate in 16.7 parts of water.
The reactor charge is heated to boiling and cooled to 95C. After the solution of (4) is charged to the reactor, there is added to the reaction medium 0.45 parts of the monomer mixture of (2) and the temperature is held at 95C without further addition of reactants for 15 minutes.
The remaining por~on o~ the monomer mixture is added simultaneously and incrementally with the solution of ~3) over a two-three hour period, while the temperature is maintained. The temperature is maintained at 95C for two hours after the addition of monomers is complete. The latex so obtained is cooled and filtered.

10717~9 ; Stcp II Coa~; i.n~ 'orm~ t 1en 2 I 'rl~e ].atex obtair)ed ln Ste~) I Or this example 1B
3 substituted for the ].atex of Step II of' Example 28 and 4 a water-ba3ed enamel 11 prepared u~lng th~ proc~dures and other ln~redlent~ u3ed to prepare the water-ba~ed 6 enamel ln Example 28. . .:
.~ ' ,; ':
: 7 EXAMPLE 30 8 The procedures of Example 28 are repeated with the dlfference that the solution resln (Step III) ls ~
prepared rrom the followlng materials: ;
~; 11 (1) There 1~ char~ed to the reactor 119 part9 ~
12 Or water and 1.8 parts of the stablllzer polymer , : 13 prepared ln Step I of Example 28. ;
14 (2) The followlng reactant monomers and chaln transrer agent are thoroughly mixed. .
~; '' , ''~.''1 16 Materlals Parts by Weight :
.~: ; . . :,~
~: ~ 17 butyl methacryl~te 10.0 ~ . ;
18: methyl methacrylate ~ 35.0 ~ ~, .
; 19 methacrylic acid 15,0 ; ~:
20 ~ butyl acrylate i 40.0 ~ '~
~. 21 . l-ootanethiol ; 1.3 ~ ' ;.. ` 22 ~ (3) There ls dls~olved 0.5 part of ammonlum ~ . :i , . 23. p~r~ul~ate in 25 part~ o~ water. : : ;,",,',`, 1~
:l24 ~ . (4) There is dissclved 0.2 parts o~ ammoni~m ;~ '~'-, 25 per~lfate ln 5 parts o~ water.
.' 26 A~ter the latex preparation pro¢edures o~ .~.i.
27 Ex~mple 28 are carrled out and the resultant lat~x . ~' 28 ls cooled ~nd flltered, the polymer i9 neutralized .,.. ~ ;
39 wlth water-soluble amine a~ ln the precedlng examples. . !

_ ~`', ; A surfactant-free hybrid water-based enamel con-t taining organic solvent is prepared using the formulation procedures of Step IV of Example 28 with the following differences:

Materials Parts by Weight .
solution polymer from example 1, Step II 7.6 Cymel 301(1) 7.0 titanium dioxide 17.4 isopropanol 2.8 : n-butanol 3.5 latex from Example 28, Step II
(emulsion polymer plus stabilizer polymer I) 51.3 10% aqueous 2-(dimethylamino) ethanol 10.4 (1) defined in Example 25.
The enamel when adjusted by water to viscosity of 20 seconds (Ford Cup No. 4) is sprayed in a conventional manner upon primed steel panels and baked for 30 minutes. The initial baking temperature is 80C. This temperature is gradually raised to 180C
and held there for at least 10 of the 30 minutes.

Step I Preparation Gf Latex A latex is prepared according to the procedures of Step II of Example 28 using the following mixture of reactant monomers and chain transfer agent:

1: 1. Materiali: ~'arti~ by Welp~ht 2: , ~3tyrerle 2.0 3 ' hydroxypropylmethacrylate ~.8.0 4 acryllc acid 2.0 butyl acrylate 'j0.0 .
6 butyl methacrylate 10.0 7 l-octanethiol o.6 - . ' . ' (1) derined in Example 25. ;:;
. . . . , 9 Step II Preparatlon of Enamel 10 : There i~ prepared a surfactant-free, 301vent-~ree, :
11 hybrld water-based enamel. The prooedures used are those .
12 Or Step I~ o~ Example 28, but with the followlng materlalq:
;'' . ~ ., ."
3 Materlals Parts by Weight ~, 14: ~ ~olu~lon polymer rrom Step III . .
15 . f Example 28 . 15.2 .
16 ~ Cymel 300(1) ~ 6.9 .
. ~17 tltanlum dioxlde 17.3 ~ ;
'x 18 ~ ~Water 5.5 ~ .:~
.. 19 latex ~rom Step I o~ thl~ Example 50,9 ~ ~:
~, 20 ~;~ ~ 10% aqueous 2-(dlmethylamlno)ethanol 4.2 ~ . ~-~ 21~ . ~ ~ (1) derined in Example 1. ~ ~, : ~22 ~`:.... 'rhls enamel i~ ~prayed on prlmed ~teel panels. -j ` ,~
23 ~ ~nd baked r 25 ~inUte~ et 160 C. ¦

~ ; ~:
.. . _ .... "'''' '' ' ' ~ , , ~ .

Il 1071789 !.` .X~!~II
2 , St~p I ~'t~(~T),~J~.Itl~n or llt(-~x I
3 ~ t(~x i3 prcl)rlred in the followin~r mar~ner:
4 (1) Therc i'3 charged to a reactor 127 part~
of water and 2.57 part3 Or ~tablllæer polymer prepared as in Example 28. .
:~. 7 (2) The followlng reactant monomer~ and chain . -~ 8 trans~er agents are thoroughly mlxed, . ;
" .~ ' . , ;'' Materlals Part~ by Wei~ht styrene 20.0 ;
11 hydroxypropylmethacrylate 18.0 12 acryllc acid 2.0 , 13 : butyl acrylate 50.0 ,.
14 butyl methacrylate 10.0 . l-octanethlol 0.6 .

1~ (3) There 15 dlssolved 0.5 parts Or ammonlum ;, 17 per~ulfate and one part o~ 2-acrylamido-2-methylpropane :
18 ; sul~onlc acld ln 16.7 parts of water. ^
~19 (4) There 15 dissolved 0.1 part~ o~ ammonium 20 ; per~ulfate in 4.17 part~ o~ water. ~J
21. ,~ The procedures of Example 29 are repeated u31ng ., 22. the materlal~ above ll~ted to prepare the latex. :,~j 2 . ~ . . ,^
23 ~; . EXAMPLE 33 . ~ , . , 24 Step I Preparation o~ Latex ~ . -, ~i, A latex 15 prepared ln the ~ollowing m~nner~
26 (1) There i~ charged to a reactor 127 part~ o~ ,;;.,~,~
27 water and 2.57 parts o~ ~tablllzer polymer prepared ;lj;`'~ .~
28 as in Example 28. ~ ' `it 29 t2) The ~ollowlng reactant monomers and cha~n : .~ ,.... t transfer agent are thoroughly mlxed. ~. `, - 56 - _ .,.. , ~ .

107~789 I ~
1 ~ Mat~ri~l~ P~rti~i by Wei~ht 2 3tyr~ne 20.0 3 hydroxypropylmetl~acryl~te 18.0 4 acryllc acid 2.0 butyl ~crylate 50.0 ; 6 butyl methacrylate 10.0 -~ , 7 l-octanethiol 0.6 ` ,;
. ., . , ; 8 ~ (3) There is dl3solved 0.5 parts Or 9 ammonlum persulfate and one part of 2-acrylamlde-2- ' 10~ methylpropane sulfonlc acid ln 16.7 partsi o~ water. ~
;,11 (4) There ls dlssolved 0.1 parts o~ ammonlum ~ ~' ~, 12 ; per~ul~ate ln 4.17 part~ o~ water.
~13 ; The proceduresi of Example 29 are repeated uslng ; !,",, ~A.' the materlals above llsted to prepare the latex. ;~ , ~ . ;, ; 15 Step II Formulatlon of Coatlng Materlal 16 , ~ The prooedures Or Step IV o~ Example 28 are repeated~ j!~
~, 17 ~ ~ubstltuting the latex prepared ln Step I of thls example ~"~f 8 - ¦ ~or the latex prepared ln Step II of Example 28, - ' ~
.; . : ~ ~ . ir 19 . . EXAMPLE 34 ~ ~.,i;
', !, ' ~'; . , . ~ ',:, . ' ~ " " ~ ; ~
; ; ;;20 ~ ; ~ ~ Thë procedures o~ Example 33 are repeated ~ , " ,,~ !~
.21; ~ ,with the dirference that the latex (let down) 1B . ~ ` ~,:,, ~22 ! ,"''.',~ ' prepared~a~i ~ollow~ ',` ,t,;~
;~ 23 ~.,;~!,, 1,;,~ ' , ' (1) There i8 charged to a reactor 12r parts 0~ ?~' ~,L
. 24 ~ wat~r and 2-84 parts o~ stablllzer polymer prepared '!~
~ rrom the materlal~ and accordlng to the procedures used ln ;~ 26 ~ Example 28.
27 - (2) The ~ollowing reactant monomer~ and ohain ~ 'i8 28 trans~er agent are thoroughly mixed. ~ , 11 ~ 57 ~
~ .

'' .

1 ¦i Materi~lia Part~ by Wel~ht 2 ~ styrene 20.0 ~, 3 ¦ methacryllc acid 15.0 .4 ¦ butyl acrylat~ . 55,0 ¦ butyl methacrylate 10.0 ~-- 6 l-o¢tanethlol 0.6 ~ .~:!
. .. ,. ,".
. . 7 (3) There is dlssolved 0.4 parts 0?~ ammonlum ! ; ~ i .- per~ul~ate and 1.0 part9 o~ 2-acrylamide-2-methylpropane ; . ". :
. 9. sul~onlc acld ln 16.7 parts of water, :~ ~
' ! ' (4) There 1~ dissolved 0.1 parts o~ ammonium : ~ i.
per~ul~ate in 4.17 part~ of water. :
. .. , ;
.: 12 The latex ls then prepared ~rom the above materlals :
. : 13 u81ng the procedures of Step II of Example 28.
' ' ' ` . . ' ' ~ ,.

. , . . , , . . ~ :;
A water-based enamel is produced ln the . ~; ;~
16 ~lrO llowing manner: ~. , r~

; 17 ~Step I Preparatlon of (let down) latex . , .. . . - ?
18(1) There is charged to a reactor 12B part~ ;' l9;of water and 2.67 part~ o~ stablllzer polymer prepared , .
,; 20 .~rom the materials and uslng the procedures o~ Step I : ,i : ~ . ;;
,. 21 ,'Or ~xample 28, . .~. ~1 .,`.2~ : ..... . (2) ~he ~ollowing reactant monomer8 and ahain ' j;~, - ;;`23itrans~er agent ar~ thoroughly mlxed. ;/., ~. :;r - j,', . . ~ .? ' ~ ~
., I . . ' ~ . ~:;
~'' 24 Materlals Parts by Wel~h~ ; i,~
styrene 20.0 "~
26 hydroxypropylmethacrylate ~ : 18.0 , ~ J.
~crylla acid .i''~ . :~
28 butyl aorylate 25.0 . in"~ .
. ,` ,,.,. ~

- 5~ - .' . .......
.... ....... . ......

bu~yl methilcryliate 35.0 '2 ' l-octanethlol 0.6 !3 (3) There 1i3 diia501ved 0.5 parts of ammonlum 4 persul~iate and 1.0 partis of 2-acrylamide-2-methylpropane ;, sulfonic acid ln 16.7 parts o~ water. ~
~,~6 (4) There ls disisolved 0.1 parts o~ ; ;;
ammonlum peraulrate in 4.17 partia Or water. ~
8 ~he latex ls prepared using the above materlals ~ .
9 and the procedure~ of Step II o~ Example 28.
. .

Step II Preparatlon o~ the Solutlon Polymer ~ 1-Z;; 11 (1) ~here i9 charged to a reactor 200 part~ o~ ~, ~12 water and 4 part~ of ~tablllzer polymer prepared ~ , j~, 13 ; ~rom the same materlal3 and procedures used to prepare ;
!''~', 14, the Rtablllzer polymer ln Example 28, , `~ 15 (2) The followlng reactant monomers and ~;
16 chaln trans~er agent are thoroughly mlxed. ;

;' 17 Materials Part~ by Wel~ht ~?. 18 methyl methacrylate 35 ~ methacryllc acld 15 ,; 20 ~ butyl acrylate 50 ~ ' ll 21i ~ 1 ootanethiol ~ ;' ";,., . ~ ;,,, .;1 ;,, 1,, 2~The solutlon polymer i8 then prepared ~rom the ; ;~ ; ~"
;;,, 23 ,abov~ material~ u31ng the procedures u~ed in Step II `~ ,?
24o~ Example 28. ~ `' ~;~ 25The latex ~o obtalned i~ neutrallzed wlth 2-(dlm~thyl-~
26amlno)ethanol to an amount equivalent to the methacryllo . , , ; 27aald constltuent Or the polymer. ;~ ,, j~ i ? ', - 59 - ',' , . ,, .

. . .

1071'789 Step III Formulation of _Coating Material A coating formulation is prepared from the following materials:

Materials Parts by Weight solution polymer from the Example Step II 17.5 Cymel 301(1) 8.7 titanium dioxide 19.8 Water 7.9 latex from this Example Step I43.5 20% aqueous 2-(dimethylamine~ethanol 2.4 (1) defined in Example 25.

The coating material is formulated from the above materials using the procedures of Step IV of Example 28.
The resultant enamel adjusted to a viscosity of 20 seconds (Ford Cup No. 4) is sprayed on prime steel panels and baked for 25 minutes. The initial baking temperature is 100C.
This temperature is gradually raised to 180C. and maintained at 180C. for at least 10 of the 25 minutes. The resultant coatings demonstrate good gloss and physical properties.
The resistance of these coatings to soaking in water at 32C for 240 hours is excellent.

~, :

f EXAMPLE 36 A water-based enamel is produced in the following I manner:
j Step I Preparation of (let down) Latex (1) There is charged to a reactor 127 parts of water and 2 parts of stabilizer polymer prepared from - 107178~

the materials and using the procedures used to prepare the stabilizer polymer of Example 28.
(2) The following reactant monomers and chain transfer agent are thoroughly mixed.

\

Materials Parts by Weight styrene 20.0 hydroxypropylmethacrylate14.0 methacrylic acid 6.0 butyl acrylate 25.0 butyl methacrylate 35.0 l-octanethiol 0.7 (3) There is dissolved 0.5 parts of ammonium persulfate in 16.7 parts of water.
(4) There is dissolved 0.1 parts of ammonium persulfate in 4.66 parts of water.
The latex is prepared from the above materials following the procedures of Step II of Example 28.
The resultant latex polymer, i.e., the emulsion polymer, has average molecular weight (Mn) of about 8,500 and a Tg of 20C.

Step II Formulation of Coating Material A coating material is prepared from the following materials:

Materials Parts by Weight solution resin from Step II, Example 35 12.6 Cymel 300(1' 7.6 titanium dioxide 21.0 107'1789 l ` latex rrom St~ I of~ th3s ~xam})l~
2 (in(~ d~3 emlllaior1 polymer and 3 ~ i3tablli~ r po].~ym(~r) 46.2 4 10% aqueous 2-(~Lmethylamlno)etl-lanol 4.2 Water 8.4

6 ~he coatlng formulation.lis prepared from : : 7 the above material~. using the procedures o~ Step i IV o~ Example 28, ,, , . , . ';' lO. The procedures of Exalnple 28 are repeated :
ll wlth the dlfferenc~ that ln pre~aring the . - ' ~;
12 soluble ~tablllzer polymer of S;ep I there is used with .:
l3 the reactant monomers 3.5 parts by weight of l-octaneth~ol, : , 14 The a~erage molecular welght (Ml) of the resultant `
15, stablllzer polymer ls about 3,0)0. It ha~ a Tg Or ~ .i 16 ~ about -8C. ~ ;~' .... ~j,~';, .:, ,: . . ~ : ' `-'". :'.
;~ii;i.17 ~ :
. . 18 The procedure~ of Example 28 are repeated wlt~
.j~. "~ ,, ,. . . , . .ii ;~, l9 ~ the dlf~erence that ln preparin~ the ~oluble stabili~er j :
;20:, polymer of Step I there is used with the reactant .
.,~ 21 monomers 0.5 parts by welght o~ l-octanethlol. The;average - .
2? molecular welght (Mn) of the re~ultant stablllzer ; . .
,~ .
23 polymer is about lO,000. It has a Tg of about -8C.

24 ; ~ A~LI_3~ .' ~,;.,~.25 - ~; ~ The procedures o~ Example 28 are repeated.~ ;,, 26 wlth the difference that ln preparing 1;he ~oluble '` ~ !`
27 stablll~er polymer o~ Step I the followlng reactant , ;,; , ,, , ., 28 monomer~ and chain trans~er agent are UBed: ; -.

, 107~789 ll 1 ~ Mat~rlcll.. ; Pnrt~, hy We~ht 2 ~ methacrylic acid 15 3 methyl methacrylate 30 4 styrene 5 butyl acrylate 40 6 butyl methacrylate 10 ~
l-octanethlol 2 ;

8 The average molecular weight (Mn) Or the .
; ... .9 re~ultant soluble stabillzer polymer is about 4~000, Its T~ 19 about 18~C. .
.", ' ~ ' . ,', 11 . EXAMPLE 40 .
12 The proGedure~ o~.~xamples 1 and 28 are . repeated ~lth the slngle difference that ln ; !
.. 14 lleu Or the commercially avallable amlno resln (Cymel . 15 . 300) crosslinklng agent there ls used a chemlcally . .
: 16 . equlvalent amount of a melamlne resln prepared , :. 17 ~ ~rom the ~ollowing materlals and ln the following . . l;
. 18 . manner: . ~
Water (400 part~ by weight), sodlum ~l ', 0 ~ hydroxlde ~3.5 part~ by welght), and para~ormaldehyde .
21 ' (326 part~ by welght) are heated to reflux and 22 refluxed 15 mlnute~. The solutlon is cooled to . . . . .
. , 23 85C, and the pH 19 adJu~ted to 8.5 wlth aqueous~ :.
.~ ~24 ..... sodlum hydroxide. Melamlne (126 part~) t~ added, and .
~l 25 . the mlxture 1~ malntained at 80-go~c rOr lo mlnutë~ i , ' ~ 26 Methanol (992 parts~ and concentrated sulfuric acld , ~ ~, 27 (36 parts) are added and the mixture ls stlrred ~or : . :
28 about one hour. Upon addltion o~ 320 parts 25~1.
~ 29 aqueou~ ~odlum hydroxide, a white preclpltate is ~ormed : 30 which 19 removed by ~lltration. Approxlmately 300 .
31 parts Or a seml-901id methylated melamlrle ar~ i~olated - 63 _ ..
., .

from the filtrate by vacuum distillation and used in the formulation of water-based enamels.

The procedures of Examples 1 and 28 are repeated with the single difference that in lieu of the commercially available amino resin (Cymel 300) crosslinking agent there is used a chemically equivalent amount of a urea-formal-dehyde resin prepared from the following materials and in the following manner:

Prl~aration of Urea-Formaldehyde Resin In a one liter three-necked flask equipped with reflux condenser, thermometer, and stirrer are placed 243 g. of 37% aqueous formaldehyde and 4-6 g. of con-centrated ammonium hydroxide to bring the pH to 7.5-8.5.
Sixty g. urea is added with stirring and the mixture heated to 100C over a one-hour period by means of a heating mantle. This temperature is maintained 10 to and 1~2 hours.
64 g. methanol is added, followed by enough phosphoric 20 acid to bring the pH to 5.5. The reaction is stirred for one hour. Water can be removed by heating 60-70 C under a water aspirator pressure of 100-200 mm. The resin can be dissolved in isopropyl alcohol to give a 60%
solution. The term "parts" when used herein without further designation shall mean "parts by weight".
The term "acrylic monomer" shall mean acrylic acid~ methacrylic acid, esters of acrylic acid and a Cl - C8 monohydric alcohol, e.g., ethyl acrylate, butyl - acrylate, hexyl acrylate and 2-ethylhexyl acrylate, 30 esters o~ methacrylic acid and a Cl - C8 monohydric alcohol, e.g., methyl methacrylate, butyl methacrylate, hexyl .~ .

' ~ ~, methylacrylate and 2-ethylhexyl methacrylate, hydroxyalkyl acrylates, e.g., hydroxyethyl acrylate and hydroxypropyl acrylate, hydroxyalkyl methacrylates, e.g., hydroxyethyl methacrylate and hydroxypropyl methacrylate, acrylamide, methacrylamide, methylolacrylamides, e.g., n-methylol-acrylamide, methylolmethacrylamides, e.g., N-methylol-methacrylamide, alkyl ethers of methylolacrylamides, e.g., N-isobutoxymethylolacrylamide, and alkyl ethers of methylolmethacrylamides, e.g., N-isobutoxymethylol-methacrylamide.
The term "copolymer of acrylic monomers" shall mean a polymer of at least two different monoethylenically :
unsaturated monomers of which more than 50 mole percent are acrylic monomers.
The term "water-dilutable organic solvent" means an organic solvent or mixture of organic solvents which is either miscible with water or will mix with water up to a concentration of at least one volume of solvent per three volumes of water without phase separation. Ordinarily, such solvent, when present in the paint, enters the paint through its use in the preparation of the solution resin, as ~-~ hereinbefore described. In such embodiment, the solution polymer is, of course, soluble therein. In another embodimènt, it may be added independently, if desired. In ; the latter case, the solution polymer may not be fully soluble therein.
While there have been described herein what ~- are at present considered preferred embodiments of the . invention it will be obvious to those skilled in the art that modifications and changes may be made ln the exemplary embodiments without departing from the essence of the invention. It is therefore to be understood that the exemplary embodiments are illustrative and not restrictive .~
of the invention, the scope of which is defined in i - 65 ,: ., . . , . : . . ~ .. ~, , ` 1071789 the appended claims, and all modifications that come within the meaning of range of equivalency of the claims are intended to be included therein.

Claims (11)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an aqueous dispersion of paint in which a carboxy-functional polymer is at least partially neutralized with a water-soluble amine and dispersed with an amino resin cross-linking agent selected from melamine-formaldehyde resins and urea-formaldehyde resins in an aqueous solution of water and a water-soluble amine, the improvement wherein the film-forming components of said dispersion of paint exclusive of said amino resin cross-linking agent comprises the combination of:
I. about 5 to about 50 parts by weight of a solution polymer which is a carboxy-functional copolymer of acrylic monomers that:
(a) is at least partially neutralized with said water-soluble amine, (b) is soluble in said aqueous solution, (c) has average molecular weight (?n) in the range of about 3,000 to about 20,000 and (d) has Tg in the range of -15°C. to 50°C., and II. about 50 to about 95 parts by weight of an emulsion polymer having functionality selected from carboxy functionality and hydroxy functionality and is a copolymer of acrylic monomers that:
(a) is essentially insoluble in said aqueous solution, (b) has average molecular weight (?n) in the range of about 3,000 to about 20,000 and (c) has Tg in the range of -15°C. to 50°C., and wherein said amino resin cross-linking agent is present in an amount in the range of about 15 to about 35 weight percent of the sum of the weights of said solution polymer and said emulsion polymer, said carboxy-functional polymer, amino resin cross-linking agent and water-soluble amine con-stituting about 30 to 50% by weight of the continuous aqueous phase of the paint, said paint having a pH of about 7 to about 10, and said water with the balance of the continuous phase being water or a mixture of water and an organic solvent, said balance constituting about 50 to about 65%
by weight of the paint.

2. The aqueous dispersion of claim 1, wherein said remainder of said aqueous phase is constituted by a mixture of water and about 5 to about 20 volume percent of an essentially non-ionizable organic solvent for said solution resin.

3. The aqueous dispersion of claim 2 wherein said organic solvent is an alcohol.

4. The aqueous dispersion of claim 1 wherein the film-forming components of said dispersion of paint exclusive of said amino resin consist essentially of about 10 to about 30 parts by weight of said solution polymer and about 70 to about 90 parts by weight of said emulsion polymer.

5. The aqueous dispersion of claim 3 wherein in addition to said solution polymer and said emulsion polymer, said paint dispersion contains a stabilizer polymer which is a carboxy-functional acrylic copolymer that is soluble in said aqueous solution, has average molecular weight (?n) below that of said solution polymer, has a Tg of -15° to 50°C, and is present in said aqueous dispersion in the range of about 0.025 to about 10 parts by weight.

6. The aqueous dispersion of claim 1 wherein in addition to said solution polymer and said emulsion polymer, said paint dispersion contains a stabilizer polymer which is a carboxy functional copolymer of acrylic monomers that is soluble in said aqueous solution, has an average molecular weight (?n) in the range of about 3000 to about 8000, has a Tg of -15° to 50°C and is present in said aqueous dispersion in an amount in the range of about 0.025 to about 5 parts by weight.

7. The aqueous dispersion of claim 1 wherein said solu-tion polymer in addition to being carboxy-functional has a second functionality selected from hydroxy functionality and amide functionality.

8. The aqueous dispersion of claim 4 having a pH in the range of 7 to about 9.5.

9.. The aqueous dispersion of claim 4 having a pH in the range of 7 to about 9.

10. In a method for producing an aqueous dispersion of paint in which a carboxy-functional polymer is at least partially neutralized with a water-soluble amine and dispersed with an amino resin cross-linking agent selected from melamine-formaldehyde resins and urea-formaldehyde resins in a continuous phase consisting essentially of water-dilutable organic solvent and an aqueous solution of water and water-soluble amine, the improvement which comprises intimately dispersing with said water, said amine resin cross-linking agent and said water soluble amine:
I. about 5 to about 50 parts by weight of a solution polymer which is a carboxy-functional copolymer of acrylic monomers that:
(a) is at least partially neutralized with water-soluble amine, (b) is soluble in said aqueous solution, (c) has average molecular weight (?n) in the range of about 3,000 to about 20,000, and (d) has Tg in the range of -15°C. to 50°C., and II. an aqueous emulsion consisting essentially of water, water-soluble amine, and about 50 to about 95 parts by weight of an emulsion polymer having functionality selected from carboxy-functionality and hydroxy-functionality and is a copolymer of acrylic monomers that:
(a) is essentially insoluble in said aqueous solution, (b) has average molecular weight (?n) in the range of about 3,000 to about 20,000, and (c) has Tg in the range of -15°C. to 50°C., said amino resin cross-linking agent being present in an amount in the range of about 15 to about 35 weight percent of the sum of the weights of said solution polymer and said emulsion polymer, said carboxy functional polymer, amino resin cross-linking agent and water soluble amine consti-tuting about 30 to 50% by weight of the continuous aqueous phase of the paint, said continuous aqueous phase having a pH of about 7 to about 10, and said water-dilutable organic solvent constitutes between 5 and 20 volume percent of said continuous phase when the combination of said water and said water-dilutable organic solvent comprises 50 to 65 weight percent of said aqueous dispersion.

11. The method of claim 10 wherein said water-dilutable organic solvent is an alcohol.