CA1065991A

CA1065991A - Non-polluting water-dispersible coating compositions

Info

Publication number: CA1065991A
Application number: CA238,752A
Authority: CA
Inventors: Girish G. Parekh
Original assignee: American Cyanamid Co
Current assignee: Wyeth Holdings LLC
Priority date: 1975-10-31
Filing date: 1975-10-31
Publication date: 1979-11-06
Also published as: FR2330730B1; BE835496A; FR2330730A1; NL7513736A; GB1523617A; DE2551277A1

Abstract

ABSTRACT

The invention is a stable water-dispersible composition of matter comprising a blend of (A) from about 15% to about 85%, by weight, of a non-ionic polyether polyol resin having only carbon, hydrogen and oxygen atoms and optionally a halogen atom, having an average molecular weight between about 300 ant 4,000, having at least two alcoholic hydroxy groups and not less than about 20%, by weight, of hydrophobic moieties derived at least in part from aromatic or cycloaliphatic materials and correspondingly not more than about 80%, by weight, of hydrophilic moieties consisting of -(CH2CH2-0-) units; (B) correspondingly from about 85% to about 15%, by weight, of a water-dispersible, non-gelled, anionic vinyl polymer having a molecular weight between about 5,000 and 100,000 and having pendant carboxyl groups, in an amount ranging between about 0.40 gram mol to 4.00 gram mols per 1,000 grams of polymer; and (C) from about 10% to about 50%, by weight, based on the total weight of (A) and (B) of a compatible aminoplast cross-linking agent having an average molecular weight not greater than about 15,00 , wherein said polymer is prepared in bulk or solution polymorization, for use as a water-dispersible coating composition.

Description

iO~ 91 This invention relates to a stable water-dispersible composition of matter comprising a blend of (A) from about 15% to about 85%, by weight, of a non-ionic polyether polyol resin having only carbon, hydrogen and oxygen atoms and optionally a halogen atom, having an average molecular weight between about 300 and 4,000, having at least two alcoholic hydroxy groups and not less than about 20%, by weight, of hydrophobic moieties derived at least in part from aromatic or cycloaliphatic materials and correspondingly not more than about 80%, by weight, of hydrophilic moieties consisting of' -(CH2CH2-0-) units; (B) correspondingly from about 85% to about 15%, by weight, of a water-dispersible, non-gelled, anionic vinyl polymer having a molecular weight between about 5,000 and 100,000 and having pendant carboxyl groups, in an amount ranging between about 0.40 gram mol to 4.00 gram mols per 1,000 grams of polymer; and (C) from about 10% to about 50%, by weight, based on the total weight of (A) and (B) of a compatible aminoplast cross-linking agent having an average molecular weight not greater than about 1,500, wherein said vinyl polymer is prepared in bulk or solution polymerization.
The present invention is in the field of polymeric materials that are particularly useful in the coating field as well as in the manufac-ture of low pressure laminates, adhesives, molding compositions, and textile treating resins. The compositions of the present invention can be used to apply a film to the surface of an existing paper web from dispersions or solutions of the compositions of the present invention. These blends can also be utilized to impregnate paper sheets for use in the manufacture of decora-tive laminates.
Blends of resinous materials have been manufactured and sold for a substantial plurality of years for a number of different purposes. Many of these blends of resinous materials have been utilized to a great extent in the coating resin art. In the earlier days, these coating compositions were dispersed or dissolved in organic solvents and upon application, the solvent was evaporated into the atmosphere. Efforts .~

~j ~06S99~.

1 have been made more recently, because of ecologlcal consid-erations, to utilize coating compositions which were dispers-ed in an aqueous medium or were applied as neat resins and cross-linked without the evaporation of any solvent. ~lany 5 of these compositions of matter are generally composed of ~, blends of reactive linear polymeric materials which have the capability of being cross-linked because of reactive sites pendant along the linear polymeric material and when these materials are cross-linked, they are converted to the ther~o-set state by the use of selected cross-linking agents. In the cross-linked state, the film is in a thermoset condition whereas before the cross-linking, the materials are poten-tially thermosetting.
The compositions of the present invention are com-posed of three (3) essential components. The first component is a non-ionic polyether polyol resin having an average mo-lecular weight between about 300 and 4,000, having at least two alcoholic hydroxy groups and not less than about 20%, by weight, of hydrophobic moieties derived at least in part from aromatic or cycloaliphatic materials and correspondingly not more than about 80%, by weight, of hydrophilic moieties consisting of -(CH2CH2-O-) units which may be derived Erom ethylene oxide~
These polyols may be prepared, for instance, by reacting a compound containing a plurality of hydroxy groups with an alkylene oxide. These hydroxy groups may be either alcoholic hydroxy groups wherein the OH group is attached directly to a carbon atom in a cycloaliphatic chain or these hydroxy groups may be phenolic hydroxy groups wherein the -OH
group is attached directly to an atoring. In other words, these compounds containing a plurality of hydroxy groups, may be aromatic or cycloaliphatic compounds or materials. These polyhydric compounds may be monomeric or part of a low molec-~0655~91 1 ular weight polymer chain such as a polymer or a phenol-for-maldehyde reaction product, many of which are well known such as the novalak resin type. Among the monomeric compounds that can be used to make the polyether polyol resin used in the present invention are the bisphenol compounds such as bisphenol A which is identified as 4,4'-isopropylidene di-phenol which is also known as 4,4'-dihydroxydiphenyldimethyl-methane. Another bisphenol is identified as bisphenol F which is 4,4'-methylenediphenol which is also known as 4,4'-dihyL
droxydiphenylmethane. Other polyhydric phenols which can be used in preparing the non-ionic polyether polyol resins used in the present invention are the dihydric phenols represented by the general formula:

lS NO ~ _ C - ~ ~

wherein the phenolic hydroxy groups may be in one of the 2,2';

2,3'; 2,4'; 3,3'; 3,4'; or 4,4' positions on the aromatic nuclei, and each of R and Rl represent hydrogen, an alkyl group, such as methyl, ethyl, propyl, isopropyl, butyl, sec--butyl, pentyl, isopentyl, hexyl, isohexyl, and the like; a cyclo(lower)-alkyl group, such as cyclohexyl or substituted cyclohexyl group, e.g., methyl-, ethyl-, propyl-, butyl-, pentyl-, and hexyl-substituted cyclohexyl, or an aromatic group, such as phenyl, tolyl, xylyl, and the like. In addi-tion, the phenolic rings may have other substituents in ad-dition to the hydroxyl group, for example, lower alkyl groups containing from 1 to 4 carbon atoms, i.e., methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, and tert-butyl groups, halogen atoms, i.e., fluorine, chlorine, bromide or iodine, and the like. It can be seen from this that these polyether polyol resins will contain only carbon, hydrogen and oxygen ~06S5~91 l atoms and optionally one or more halogen atoms.
An illustrative, but by no means exhaustive, list-ing of dihydric phenols falling within this general formula includes 4,4'-dihydroxydiphenyldimethylmethane ~bisphenol A), 2,4'-dihydroxydiphenylethylmethane, 3l3'-dihydroxydiphenyl-diethylmethane, 3,4'-dihydroxydiphenylmethylpropylmethane, 2,3'-dihydroxydiphenylethylphenylmethane, 4,4'-dihydroxyd-iphenylpropylphenylmethane, 4,4'-dihydroxydiphenylbutylphenyl-methane, 2,2'-dihydroxydiphenylditolylmethane, 4,4'-dihydroxy-diphenyltolylmethylmethane, and the like.
In addition to these aromatic compounds, it is pos-sible to use such cycloaliphatic diols as cyclohexane dimeth-anol, 4,4'-isopropylidene dicyclohexanol, tricyclo[4.].1.0 ' ]
decane-4,8-dimethanol and 4,4'-dihydroxy dicyclohexyl methane.
Other polyhydric cyclo aliphatic compounds are the lower al-kyl derivatives of the above compounds which contain one or more Cl-C4 substituents.
Among the alkylene oxides what may be reacted with the polyhydric compounds such as those set forth hereinabove are ethylene oxide, propylene oxide, butylene oxide and ole-fin oxides with a chain length of C5-C18, styrene oxide, 4--oxatetracyclo-(6.2.1.02'7, 03'5) undecan-9(10)-ol and simi-lar mono epoxy compounds derived from aliphatic, cycloaliphatic and aromatic hydrocarbons. With the exception of ethylene oxide, all other alkylene oxide compounds impart hydrophobic moieties to the polyol.
The expression "derived at least in part from aro-matic or cycloaliphatic materials", as used herein, signifies that there must be present in these polyol resins aromatic or cycloaliphatic hydrophobic moieties but additionally there may, and in most instances, there will be other hydrophobic acyclicaliphatic moieties. For instance, when bisphenol A
is used to make a polyol resin, there will be aromatic moiet-1~5~9~

ies from the bisphenol A but there also will be an isopropylidene hydrophobicmoiety position between the two aromatic rings. By the same token, when hydrogenated bisphenol A is used, there will be cycloaliphatic moieties de-rived from the cyclohexane rings but additionally there will be an isopropyl-idene hydrophobic moiety between each pair of cyclohexane rings.
As preferred polyether polyols there are mentioned the reaction product of 4,4'-methylene diphenol and ethylene oxide, the reaction product of 4,4~-methylene diphenol and propylene oxide and the reaction product of a phenol-formaldehyde resin and propylene oxide.
In order that the non-ionic polyether polyol resins used in the present invention may be more completely identified, the following examples are set forth in which all parts are parts by weight unless otherwise indi-cated. These examples are set forth primarily for the purpose of illustration and any specific enumeration of detail contained therein should not be inter-preted as a limitation on the case except as is indicated in the appended claims. In these examples, certain polyethers are disclosed which are commer-cially available. These polyethers are made by the method shown with the reactants illustrated and have the properties set forth hereinbelow.
Polyether A is prepared by reacting 1 mol of bisphenol F (4~4~-methylene diphenol) with 2 mols of propylene oxide. The reaction product thus produced is then reacted with 7 mols of ethylene oxide. The resulting product has a viscosity of 1650 centipoises and a hydroxyl number of 225.
The molecular weight of the product is about S00. This product has about 49% hydrophilic moieties and about 51% hydrophobic moieties. Polyether A is a liquid.
Polyether B is prepared by reacting 3 mols of phenol under acidic ~ - 5 -~C
~ . .

lU6SS~9~

conditions with 2 mols of formaldehyde. The resulting product is then react-ed with 9 mols of ethylene oxide. The resulting polyether has a viscosity of 11,700 centipoises, a hydroxyl number of 244 and a functionality of 3. Poly-ether B has a molecular weight of about 680. This - 5a -.~.

10659gl 1 product has about 56% hydrophilic moieties and about 44% hy-drophobic moieties. Polyether B is a liquid.
Polyether C is prepared by reacting 1 mol of the phenol formaldehyde reaction product of polyether B in se-quence with 3 mols of ethylene oxide and then with 3 mols ofpropylene oxide. The resulting polyether has a viscosity of 132,000 centipoises and a hydroxyl number of 291. The molec-ular weight is about 570. This product has about 22~ of hy-drophilic moieties and about 78% hydrophobic moieties. Poly-ether C is a liquid.
Polyether D is prepared by reacting 1 mol of bis-phenol A (4,4'-isopropylidene diphenol) with 6 mols of ethyl-ene oxide. The resulting product has a viscosity of 2,840 centipoises and a hydroxyl number of 215. The molecular weight of polyether D is about 520. This product has about 54% hy-drophilic moieties and about 46% hydrophobic moieties. Poly-ether D is a liquid.
Polyether E is prepared by reacting 1 mol of bis-phenol A with 6 mols of propylene oxide. The resulting prod-uct has a viscosity of 8120 centipoises and a hydroxyl numberof 199. Ihe molecular welght of the polyether E is about 565. This product has about 0% hydrophilic moieties and about 100~ hydrophobic moieties. Polyether E is a liquid.
Polyether F is prepared by reacting 1 mol of hydro-genated bisphenol A with 10 mols of ethylene oxide. The prod-uct has a molecular weight of 601, a hydroxyl number of 158 and is a solid. The polyether contains about 65% hydrophilic moieties and 35% hydrophobic moieties.
Polyether G is prepared by reacting 1 mol of bis-phenol A with 10 mols of ethylene oxide to produce a liquidproduct having a molecular weight of 679. The hydroxyl num-ber is 154. Polyether F contains about 66% of hydrophilic groups and 34% of hydrophobic groups.

~06599~
1 Polyether H is prepared by reacting 1 mol of bis-phenol A with about 21 mols of ethylene oxide to produce a waxy solid having a molecular weight of about 1150 and an hydroxyl number of 98. The polyether contains about 80% of hydrophilic groups and about 20% of hydrophobic groups. This polyether is soluble in water.
Polyether I is prepared by reacting 1 mol of Poly-ether F with 12.5 mols of ethylene oxide to produce a hard waxy solid having a molecular weight of 1300, an hydroxyl ~um-ber of 88, and contains about 80% of hydrophilic ethyleneoxide moieties and about 20% hydrophobic moieties.
Polyether J is prepared by reacting 1 mol of bis-phenol A with 10 mols of propylene oxide. The resulting prod-uct has a hydroxyl number of 140 and molecular weight about 770. This product has 0% hydrophilic moieties and 100~ hy-drophobic moieties. This polyether is normally liquid.
Polyether K is prepared by reacting 1 mol of bis-phenol A with 6 mols of propylene oxide and 2 mols of ethyl-ene oxide. The resulting product has a hydroxyl number of 169 and molecular weight about 664. This product has 13.7%
hydrophilic moieties and 86.3% hydrophobic moieties. ThiS
polyether is normally li~uid.
Polyether L is prepared by reacting 1 mol of bis-phenol A with 6 mols of propylene oxide and 12 mols of ethyl-ene oxide. The resulting product has a hydroxyl number of100 and molecular weight about 1140. This product has 47.8%
hydrophilic moieties and 52.2% hydrophobic moieties. This polyether is normally liquid.
The amount of the non-ionic polyether polyol resin used as component (A) in the composition of the present inven-tion may be varied between about 15% to about 85%, by weight, based on the total weight of the polyether polyol resin and the non-gelled anionic vinyl polymer material having the pend-- 1065S~9~
1 ant carboxyl groups. The amount of (B), the non-gelled an-ionic vinyl polymeric material, used with the polyether polyol resin is correspondingly from about 85% to about 15%, by i weight, on the total weight of (A) and (B). The proportions of (A) and (B) to be used are dependent upon a number of fac-tors. These include the hydrophobic/hydrophilic balance of the components and the use of the coating. For example, if a very hydrophobic polyether polyol is to be used, i.e. one with a high ratio of hydrocarbon moieties to ethylenoxy groups, it is desirable to use a larger proportion of the non-gelled, anionic polymer. Since one of the functions of the vinyl polymer is to serve as a dispersing agent for the ~
polyether polyol, more is needed with a more hydrophobic poly-ol. On the other hand, if a more hydrophilic polyol is being used, it would be normal to use a smaller proportion of the anionic, non-gelled vinyl polymer. It will be understood that a considerable range of proportions is possible with pairs of polyol and vinyl polymer components, but not every set of proportions is suitable with every pair. With respect to the final coating properties, the vinyl polymer generally improves the chemical resistance properties of the coating and makes it easier to apply; the polyether polyol on the other hand improves the flexibility of the coating, increases the application solids achievable and reduces the amount of neutralizing amine required. Thus, a formulator skilled in the art may prepare coatings with a range of properties by varying the proportions of the components according to the above considerations. Whatever the percentages used, the total percentages of (A) and (B) will be 100%.
The second essential component in the composition of the present invention is a water-dispersible non-gelled anionic vinyl polymeric material prepared by polymerizing at least some a,~-ethylenically unsaturated carboxylic acid with lO~S~91 l other polymerizable vinyl monomers of the acrylic or non--acrylic types wherein the a,~-ethylenically unsaturated car-boxylic acid is used in amounts sufficient to provide pendant carboxyl groups in the polymer in an amount ranging between about 0.40 mol to 4.00 mols per thousand grams of polymer.
These vinyl polymers having pendant carboxyl groups will have an average molecular weight varying between about 5,000 and 100,000. The amount of the vinyl polymer used will in some instances vary inversely with the molecular weight. When the molecular weight is about 100,000 the amount used should be 15% or an amount closer to the lower limit than the upper limit of 85~. On the other hand when the molecular weight of the vinyl polymer is low, such as around 5,000, the amount used can cover the entire range of weight percentages. These water-dispersible non-gelled anionic vinyl polymeric materials can be prepared by polymerizing for instance an a,~-ethylen-ically unsaturated mono or polycarboxylic acid and an alkyl ester of a,~-ethylenically unsaturated monocarboxylic acid with or without any further modifying polymerizable acrylic or non-acrylic monomer. These water-dispersible non-gelled anionic vinyl polymers may be simple copolymers or they may be terpolymers or tetrapolymers of higher polymer components in which an additional acrylic or non-acrylic monomer is ut-ilized. When only the a,~-ethylenically unsaturated type acid monomer and the acrylic type ester monomer are used to form a copolymer, one would generally use a sufficient amount of the acidic material so as to provide in the ultimate vinyl polymer pendant carboxyl groups in an amount ranging between about 0.40 gram mol to about 4.00 gram mols per 1,000 grams of polymer.
The term "water-dispersible" as used herein applies to both true and micellar solutions as well as dispersions in which the polymer is only suspended in the aqueous medium.

1 The polyols used in the compositions of the present invention should be substantially free of any reactive groups that would interfere with the in situ polymerization of the polymerizable monomers. Reactive groups such as epoxy groups, episulfide groups and the like will interfere with the poly-merization by causing premature cross-linking and/or premature gellation.
All of these anionic water-dispersible non-gelled polymeric materials will have pendant reactive carboxyl gr~ups but additionally may or may not have pendant reactive alco-holic hydroxy groups and/or pendant reactive amide groups.
The water-dispersibility of the polymeric material is achieved by full or partial neutralization of the ionizable carboxyl groups pendant from the chain. In addition, the carboxyl groups provide sites which are reactive with cross-linking agents. Since a smaller number of groups are required for dispersibility than for effective cross-linking of the poly-mer, polymers which contain hydroxy or amide reactive sites will normally have fewer carboxyl groups than those which have only carboxyl groups as the reactive sites. All three of these classes of groups are water-sensitive sites and these water-sensitive sites should be tied up in inter-reaction with a cross-linking agent in a cross-linking mechanism. Be-fore the cross-linking takes place, the cross-linking agent will function as a plasticizer for the total composition.
The anionic polymeric materials prepared by vinyl polymerization may be prepared separately by either solution or bulk polymerization, both of which procedures are thoroughly well known in the art, and therefore, it is not deemed neces-sary to elaborate upon such procedures here. Additionally,these vinyl monomers may be polymerized in the presence of the non-ionic polyether polyol resin with or without benefit of any other diluent, depending upon whether the polyol resin ` ~06~99~.

1 is normally liquid or a solid, since these vinyl monomers are for the most part soluble in these polyether polyol res-ins or vice versa. The in situ polymerization technique pro-vides a very convenient way to prepare the compositions of the present invention. In the polymerization, the polyol acts as a solvent for the acrylic polymer; however, when the composition is later formulated into a coating, the polyol becomes a reactive functional material rather than a volatile inert solvent. Thus a coating with greatly reduced pollution potential is obtained. The polymerization reaction in situ would be carried out under conventional polymerization condi-tions, namely by feeding the blend of vinyl monomers into the polyether polyol at a temperature of between about 60~C. and 180C. in the presence of a polymerization catalyst such as a peroxide catalyst, all of which is well known in the art.
The in situ polymerization of the acrylic monomer blend in the polyether polyol may result in grafting of the acrylic polymer onto the polyether polyol. Thus, the final composition in the in situ polymerization may contain some molecules in which vinyl polymer is grafted onto the poly-ether polyol.
If the non-gelled anionic vinyl polymer is prepared by polymerization in situ in the non-ionic polyether polyol resin, the compatible aminoplast cross-linking agent can be added thereto in the selected amounts. On the other hand, if the anionic vinyl polymer is separately prepared, it may be added to the polyether polyol resin and then the amino-plast cross-linking agent added thereto or the polyether polyol resin may be added to the aminoplast cross-linking agent fol-lowed by the addition of the anionic vinyl polymer. Alterna-tively, the anionic vinyl polymer may be added to the amino-plast cross-linking agent followed by the addition of the polyether polyol resin or one may introduce all three com-` 10655~9~
1 ponents into a suitable mixing vessel thus making the totalblend of the three components simultaneously.
It is possible to prepare the compositions of the present invention by mixing a solution of the acrylic polymer with the polyol; such a composition can be used to prepare high performance coatings similar to those available from the in situ polymerization. Further, a composition free of organic solvent could be prepared either by distilling the solvent from the above composition or by dissolving a solid acrylic polymer in polyol. Although each of these methods gives rise to compositions useful for formulating coatings, the direct polymerization of the vinyl monomers in the polyol is the preferred method of preparation because it is the simp-lest and most economical method of manufacture.
The vinyl polymers may be prepared by polymerizing acidic polymerizable monomers such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, ~-benzoyl acrylic acid, and polycarboxylic acids of the a,~-ethylenically unsaturated class such as maleic, fumaric, itaconic, mesaconic, aconitic, and the halogenated acids such as halogenated maleic or more specificatlly, chloromaleic acid, and the like. These acidic materials may be copolymerized or polymerized with other mono-mers which contain no carboxyl groups such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, decyl acryl-ate, lauryl acrylate, methyl methacrylate, ethyl methacrylate,butyl methacrylate, heptyl methacrylate, decyl methacrylate, propyl crotonate, butyl crotonate, nonyl crotonate, and the like.
If desired, one can modify the basic copolymer of the present invention by copolymerizing therewith one or more different polymerizable monomers but the amount of these dif-ferent monomers, depending on their characteristics should not be so great as to detract from the anionic characteristics ~()65S~91 f 1 of the acrylic polymeric material. In this connection one could use such polymerizable compounds as styrene, ortho-, meta or paraalkyl styrenes such as the o-, m-, or p-methyl, ethyl, propyl, and butyl styrenes, 2,4-dimethyl styrene, 2,3--dimethyl styrene, 2,5-dimethyl styrene, vinyl naphthalene, acrylonitrile, methacrylonitrile, halo ring, or side chain styrenes such as a-chloro styrene, ortho-, meta or para--chlorostyrenes, 2,4-dichlorostyrene, 2,3-dichlorostyrene, 2,5-dichlorostyrene, or the alkyl side chain styrenes such' as a-methyl styrene, a-ethyl styrene, and the like. Addition-ally, one can make use of such polymerizable vinyl monomers as acrylamide, methacrylamide, ethacrylamide, N-tertiarybutyl-acrylamide, and the like.
If it is desired to incorporate polymerizable mon-omer moieties containing an alcoholic hydroxy group into the basic copolymer chain one can produce an anionic polymeric material of this description by polymerizing the a,~-ethyl-enically unsaturated carboxylic acid and the alkyl ester of ~ -ethylenically unsaturated carboxylic acid with a polymer-izable vinyl monomer which contains an alcoholic hydroxy groupsuch as the hydroxyl alkyl esters o~ a,~-ethylenically un-saturated monocarboxylic acid such as the hydroxy alkyl est-ers of acrylic acid, methacrylic, ethacrylic acids and chloro as well as the other halo-substituted acrylic acids. These esters may either have a primary or a secondary hydroxyl group.
Illustrative of the types of compounds that may be used as comonomers in preparing the anionic, polymeric material are 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxy-propyl acrylate, 2-hydroxybutyl acrylate, 8-hydroxyoctyl ac-rylate, 2-hydroxyethylmethacrylate, 5-hydroxyhexylmethacrylate, 6-hydroxyoctylmethacrylate, 8-hydroxyoctylmethacrylate, 10-hydroxydecylmethacrylate, 3-hydroxypropyl crotonate, 4-hy-droxyamyl crotonate, 5-hydroxyamyl crotonate, 6-hydroxyhexyl 106599~

1 crotonate, 7-hydroxyheptyl crotonate, 10-hydroxydecyl croton-ate, and the like. These hydroxy esters may be used either singly or in combination with one another with other polymer-izable vinyl monomers devoid of any alcoholic hydroxy group including those set forth hereinabove in the discussion of the carboxyl group containing monomers. Additionally, one can make use of other hydroxyl-containing polymerizable vinyl monomers such as methylolacrylamide, methylolmethacrylamide, and the like.
The compositions of the present invention are par-ticularly useful as coating compositions and are outstand-ingly attractive for this purpose since they can be used without any organic solvent, which when used, may tend to pollute the atmosphere upon the evaporation of the organic solvent from the coating. When applied to a substrate such as an iron phosphated steel panel by spraying and thereafter baking, the three essential components react with one another to form a thermoset or cross-linked coating on the substrate.
Because the blend of these components in the presence of a small amount of base is frequently water-soluble and almost invariable water-dispersible, these compositions can be di-luted with water to any selected solids content. If a clear coating is desired, the blend of the three essential compon-ents reduced to application solids with water can be used.
However, pigmented coatings can be prepared by the use of conventional commercially available pigments such as titanium dioxide, iron oxide red pigment and the like. These composi-tions are useful as coating compositions for metal, wood, plastics, textiles, paper, glass, and the like. These compo-sitions can be applied by spraying, dipping, roller coatingor brushing techniques, and the like.

The rate of cure of the coatings of the present invention may be increased by addition of acid catalyst. For 1l)6SS~9~
1 this purpose, there may be used any of the conventional acid catalysts for organic coatings such as p-toluene sulfonic acid, dodecyl benzene sulfonic acid, phosphoric acid, and the like. Where acid catalysts are used, best stability of the coating is achieved by adding sufficient amine to neutral-ize the catalyst. Since levels of acid catalyst are general-ly low, this usually requires only a small increase in the amount of amine.
When the selected polyether polyol resins, the com-patible alkylated aminoplast cross-linking agent and water-dispersible non-gelled anionic polymeric material are used together, stable water-dilutable systems can be formulated which give a performance equal to or better than existing water-soluble and solvent-based systems. Furthermore, the novel coatings of the present invention have displayed ex-cellent paint stability over long periods of time without impairment in performance.
Another advantage of the coatings of the present invention is that they require much less neutralizing amine than most conventional water-based coatings. In most water--based coatings, the amine is used to improve the water-dis-persibility of the acidic po]ymer resin. The coatings of the present invention may be formulated with much less amine since none is required to neutralize the polyether polyol components. For example, where the neutralizing amine is dimethylaminoethanol, a conventional water-based coating might require from 5-15%, by weight, of amine on the paint solids. Coatings of the present invention can be formulated with 1-3~ of amine on the same basis. Proportional reductions can also be made if amines of different molecular weight such as ammonia or triethyl amine are used. Since high levels of amine are undesirable pollutants, the reductions described are significant and desirable.

06SS~9~

Although the compositions of the present invention are water-dispersible, they may be formulated into high performance coatings using organic solvents as whole or partial replacements for the water. However, since one of the objectives of the present invention is to minimize pollution potential, it is preferred to use water as the solvent.
When it is desired to use the blend of the (A) polyether polyol and the (B) vinyl polymer as a coating resin that is convertible to the thermoset state, a compatible aminoplast cross-linking agent is used in a~
amount varying between 10% and 50%, by weight, based on the total weight of (A) and (B).
The aminoplast cross-linking agents used in the present invention may be either alkylated or unalkylated. They should be alkylated when used in coating compositions but for other uses such as in laminating operations, adhesives and mol~ing compositions among others they are preferably unalky-lated.
The alkylated aminoplast cross-linking agents can be prepared by reacting a urea with an aldehyde such as formaldehyde and then alkylating said urea-formaldehyde reaction product with a lower alkanol such as methanol, ethanol, propanol or butanol. In addition to urea per se, one could make use of ethyleneurea, thiourea, and the like. Additionally, one can make use of the amino-triazine aldehyde reaction products that have also been alkylated with comparable alkanols. In this connection, attention is directed to United States Patent No. 2,197,357 issued April 16, 1940 to Widmer, et al, which shows a substantial plurality of amino-triazines re-acted with aldehydes that are then alkylated by reaction with a substantial plurality of compounds containing an alcoholic hydroxy group. The said patent discloses a plurality of guanamines such as formoguanamine and acetoguanamine which can be used to form compatible alkylated amino-i S~91 plast cross-linking agents. These cross-linking agents can be, and prefer-ably are, monomeric. Illustrative of such a monomeric aminoplast cross-linking agent is hexakis (methoxymethyl) melamine. This monomeric compound can be prepared by a plurality of different processes such as those shown in United States Patents 2,918,452 issued December 22, 1959 to Kun et al and 2,998,411 issued August 29, 1961 to Housekeeper. Unmixed ethers of the polymethylol triazines can be used as well as mixed ethers such as the tetrakis (alkoxymethyl) benzoguanamines may be used which are disclosed in United States Patents 3,091,612, issued May 28, 1963 to Stevens. A lengthy dis-- 10 ser~ion on fully mixed ethers of hexamethylol melamine is set forth in United States Patent 3,471,388, issed October 7, 1969 to Koral. The un-alkylated melamine resins are shown in United States Patent 2,260,239 issued October 21, 1941 to Talbot.
In addition to the urea family and the triazine family of alky-lated aminoplast cross-linking agents, one may also make use of the aniline formaldehyde reaction products, a plurality of which are available commercial-ly. These aniline reaction products should be limited to use in those com-positions in which darker colors are not objectionable.
In addition to using these cross-linking agents in the monomeric state, one may use low polymers of these reaction products such as dimer, trimer, tetramers, and the like and mixtures thereof. It is generally prefer-red to utilize a cross-linking agent that has an average molecular weight not greater than about 1,500.
If water-dilutability of these cross-linking agents is desired, methanol is preferably used as the alkylating agent. These aminoplast cross-linking agents may be used either singly or in combination with one another.
In either case, the weight proportions remain the same.
In general, the most efficient aminoplast cross-linking agents are the highly alkylated, largely monomeric resins. For example, commerical grades of hexamethoxymethyl-,:, ~065S~9~

melamine are very suitable cross-linking agents for the polyol/vinyl polymer compositions. Similarly, highly alkylated urea and benzoguanamine resins are very suitable aminoplast cross-linking agents. Although the more mono-meric materials, in a mixture of monomers, dimers, trimers, etc., are usually preferred because of their efficiency and because of the better flexibility of the resultant coatings, in some circumstances, a more polymeric, partially methoxymethylated melamine cross-linking agent may be desirable in coatings where faster cure is needed. When using partially polymerized partially alkylated resins~ it is necessary to maintain compatibility, so that alkyla-tion must not be too low or molecular weight too high.
As preferred cross-linking agents, mention is made of alkylated Cl-C4 urea formaldehyde~ especially butylated urea-formaldehyde, alkylated Cl-C4 benzoguanamine-formaldehyde and fully methylated urea-formaldehyde cross-linking agents.
It has been indicated hereinabove that the compositions of the present invention make novel coating systems which result in extremely hard and mar-resistant coatings which are nevertheless very flexible. It is possibleon the other hand to formulate soft and rubbery coatings which are similar in appearance to vinyl organosol coatings. When the selected poly-ether polyol resins, the non-gelled anionic vinyl polymeric materials, and the compatible alkylated aminoplast cross-linking agents are used, stable water-dilutable systems can be formulated free of any organic solvents, which give a performance equal to or better than existing water-soluble and solvent based systems.
With normal water-soluble coating systems, it is difficult to ob-tain paint stability. The novelcoatings of the present invention have dis-played excellent paint stability over long periods of time without impair-ment in performance.

106S5~9~

The following is a typical illustration of the procedure for the preparation of the water-dispersible compositions of the present invention.
These examples are set forth primar;ly for purposes of illustration and any specific enum-- 18a -~ 6599~

1 eration of detail contained therein should not be interpreted as a limitation on the case except as is indicated in the appended claims.
Example 1 Into a suitable reaction vessel equipped with a stirrer, a nitrogen inlet tube and a reflux condenser there is introduced 50 parts of polyether D. There is then added 50 parts of a monomer blend comprising 50.5% n-butylacrylate, 22.95% styrene, 6.15% acrylic acid, 18.4% of 2-hydroxyethyl-acrylate, together with 1% of di-t-butylperoxide and 1% of n-dodecyl mercaptan. The catalyzed monomer mixture is added slowly to the polyol under a blanket of nitrogen at 160C.
over a period of about two hours. The polymerization temper-ature is maintained at 160C. for an additional one to two hours. The reaction product is then cooled to room temperat-ure and the resultant resin is 100% non-volatile and had a viscosity of 1,140 poises at 25C. The Gardner color is less than one.
Example 2 Into a suitable mixing vessel, there is introduced 84 parts of a mixture of the polyol and acry].ic polymer of Example 1 and 28 parts of hexakis(methoxymethyl)melamine fol-lowed by 3 parts of dimethylamino ethanol, DMAE, and 0.5 part of n-dodecyl benzene sulfonic acid, an acid catalyst. To the resultant mixture, there is added 88 parts of titanium dioxide (rutile type) under high speed agitation. After good dispersion of the pigment, which is generally achieved in about 15-20 minutes, 240 parts of deionized water are added in small portions. The resultant aqueous paint of about 45%
solids has a pH of 7.5 and a Ford cup No. 4 viscosity of 45 seconds. The aqueous paint was then sprayed on cold rolled steel panels that had been pretreated with zinc phosphate.
The coated panels are then baked at 150C. for 20 minutes.

~0655~9~
1 The film properties on these panels are shown in Table 1 hereinbelow.
Example 3 Example 1 is repeated in all essential details ex-cept that there is used 30 parts of the polyether polyol D
and 70 parts of the same acrylic monomer mix. The polymeri-zation temperature is 145C. and the viscosity at 25C. was very high.
Example 4 Example 2 is repeated in all essential details ex-cept that there is used 70 parts of the mixture of the polyol and the acrylic polymer and 30 parts of hexakis(methoxymethyl)-melamine, 1.8 parts of dimethylaminoethanol, 0.4 part of n--dodecyl benzene sulfonic acid, and 80 parts of titanium di-oxide. After the mixing, sufficient deionized water was added in small portions so as to produce a solids content of the paint in water of 39.0%. The paint was sprayed on a number of cold rolled steel panels pretreated with iron phosphate.
Some of the panels were baked at 150C. for 20 minutes while others were baked at 175C. for 20 minutes. The film proper-ties on these panels are shown in Table 1 hereinbelow.

Example 1 is repeated in all essential details ex-cept that there is used a total of 35 parts of the acrylic monomer composition as used in Example 1 together with 35 parts of polyether E. The polymerization is carried out at 165C. The resinous polymeric mixture, in combination with 30 parts of hexakis(methoxymethyl)melamine, is then emulsified with 125 parts of water in the presence of 2.5 parts of di-methylaminoethanol to provide a 44% solids solution. Theviscosity of the emulsion at 25C. was Z6 on the Gardner-Holdt scale (234 poise). The emulsion had a clear bluish appearance.

1065S~9~

1 Example 6 Example 4 is repeated in all essential details ex-cept that 70 parts of the polyol polymer blend of Example 5 obtained before the emulsification, are blended with 30 parts of a salicylic acid reaction product of dimethoxymethyl diethoxymethyl benzoguanamine and 2.25 parts of diethanolamine, instead of dimethylaminoethanol. The water dispersed paint of 47% solids was sprayed on a number of cold rolled steel panels pretreated with zinc phosphate. After spraying, some of the panels were baked at 175C. for 20 minutes. The re-sults are set forth hereinbelow in Table 1.
Example 7 Into a suitable reaction vessel equipped as in Ex-ample 1, there is introduced 35 parts of polyether polyol D
to which there is added 35 parts of a mixture of the follow-ing monomers: 54. 8 ~ of n-butylacrylate, 26.5% styrene, 14.9%
acrylic acid, together with 1.9~ of di-t-butylperoxide and 1.9~ of n-dodecyl mercaptan. The monomeric mixture is added slowly to the polyol under a blanket of nitrogen at a temp-erature of 160C. over a period of about 2 hours. The reac-tion temperature is maintained after the addition is complet-ed at 160C. for an additional 1 to 2 hours. The reaction product was cooled to room temperature followed by the addi-tion of 30 parts of hexakis(methoxymethyl)melamine. The re-sultant 100~ non-volatile resinous mixture is then emulsified in the presence of 2.5 parts of DMAE with 65 parts of deion-ized water to 60% solids. The viscosity of the emulsion at 25C. was 100 poises and had a clear bluish appearance.
Example 8 In a suitable mixing vessel, there is introduced 165 parts of the clear emulsion of Example 7. To this are added 0.4 part of n-dodecyl benzene sulfonic acid and 80 parts of titanium dioxide. After the dispersion of the pig-~06599~
1 ment in 10-15 minutes, 55 pa-ts of deionized water is added in small portions to produce the water dispersed paint of 60~ solids. Films are drawn down on cold rolled steel panels pretreated with iron phosphate and the films are baked at 150C. for 20 minutes. The film properties are shown in Table 1 hereinbelow.
Example 9 Example 7 is repeated in all essential details ex-cept that there is used only 25 parts total of the monomer' mix used in Example 7 and 75 parts of the polyether polyol D. The polymerization was carried out at 150C. The result-ant polymer-polyol of 100% solids had a viscosity of 384 poises at 25C. and a Gardner color of less than one.
Example 10 The procedure of Example 2 is followed in all es-sential details in which 70 parts of the blend of polyol and ; acrylic polymer of Example 9 are blended with 30 parts of hexakis(methoxymethyl)melamine and to the 100 parts of the polyol/acrylic polymer/cross-linking agent blend, there is mixed 80 parts of titanium dioxide pigment. There is used 4.1 parts of diisopropanolamine. The paint was cut with de-ionized water to an 80% solids and films were drawn down on cold rolled steel panels pretreated with iron phosphate and the films were then baked at 150C. for 20 minutes. The film properties on the steel plates are found in Table 1 herein-below.
Example 11 Example 1 is repeated in all essential details ex-cept there is used only 25 parts total of the polymerizable monomers used in Example 1 and 75 parts of the polyether poly-ol E. The polymerization is carried out at 150CC. and a 100~
solids solution of the mixture of polymer and polyol was Z6+on the Gardner-Holdt scale at 25C. and had a Gardner color of 106599~

1 less than one.
Example 12 70 Parts of the mixture of the polyether polyol and the acry]ic polymer of Example 11 are blended with 30 parts of hexakis(methoxymethyl)melamine which is then blend-ed with 80 parts of titanium dioxide pigment. There is used 2 parts of diethanol amine and 0.4 part of n-dodecyl benzene sulfonic acid. The paint was cut to a solids content of 65%
with deionized water. Cold rolled steel panels pretreated with zinc phosphate were coated with films of this paint and they were then baked at 150C. for 20 minutes. The film prop-erties are shown for this paint in Table 1 hereinbelow.
Example 13 An acrylic resin is prepared in a conventional manner by polymerizing a mixture of 41 parts of n-butylacryl-ate, 50 parts of methyl methacrylate and 9 parts of acrylic acid in 2-ethoxyethanol and using dicumyl peroxide as a cat-alyst and dodecyl mercaptan as a chain transfer agent to yield a 75% solids solution of the polymer in the solvent. The polymeric material has a molecular weight of about 10,000--15,000 and has an acid number of 72. 50 Parts (solids) of the acrylic polymer is blended with 50 parts of polyether , polyol J. Thereupon, 70 parts of this blend are mixed with 29.2 parts of hexakis(methoxymethyl)melamine and 0.8 part of dodecyl benzene sulfonic acid. Methyl diethanol amine is used in a sufficient amount to neutralize at least some of the carboxylic groups in the polymer. A paint is prepared therefrom by adding titanium dioxide in a pigment/binder ratio of 80/100 respectively. The paint is prepared substantially in the manner set forth in Example 2 hereinabove. The paint was cut with deionized water in a sufficient amount to pro-duce an aqueous paint of about 54% solids, having a pH of 8.1 and a Ford cup No. 4 viscosity of 85 seconds. Films are 106S~9l 1 drawn down on cold rolled steel panels that had been pretreat-ed with zinc phosphate and some of the coated panels are then baked at 150C. for 20 minutes and other panels were baked at 175C. for 20 minutes. The film properties on these panels are shown in Table 1 hereinbelow.
Example 14 Example 13 is repeated in all essential details except that in the place of the polyether polyol J there was substituted an equal amount of polyether polyol K. The paint was cut with deionized water to a solids content of 47~ sol-ids and has a pH of 7.9 and a Eord cup No. 4 viscosity of 73. As in Example 13, films were drawn down on cold rolled steel panels that had been pretreated with zinc phosphate.
Some of the coated panels were then baked at 150C. for 20 minutes while others were baked at 175C. for 20 minutes.
The film properties of these panels are shown in Table 1 here-inbelow.
Example 15 Example 13 is repeated in all essential details except that in the place of the polyether polyol J there was used an equal amount of polyether polyol L. The ~aint was cut with deionized water to a solids content of about 50~
and it had a pH of 7.9 and a Ford cup No. 4 viscosity of 75.
Films are drawn down, as in Example 13, on cold rolled steel panels, pretreated with zinc phosphate, and some of the coat-ed panels are then baked at 150C. for 20 minutes while others are baked at 175C. for 20 minutes. The film properties of these panels are shown in Table 1 hereinbelow.

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~D CO t~ D o o O n n X ~ R ~n~ R 11 11 1~;5~91 1 It has been indicated hereinabove that the water--dispersibility of the non-gelled, ionic vinyl polymer is achieved by full or partial neutralization of the ionizable carboxyl groups pendant from the chain. This can be accomp-lished by the use of water-soluble amines of which a plural-ity are available commercially and have been illustrated in the examples set forth hereinabove. Additionally, one can use ammonia or ammonium hydroxide or the alkali materials such as sodium hydroxide, potassium hydroxide, lithium hy-droxide and the like. The amount of the amine, the ammonia,ammonium hydroxide or alkali material used should be only that amount which is required to achieve water-dispersibility.
If water-dispersibility is achieved by only partial neutrali-zation of the ionizable carboxyl groups, that is sufficient.
However, if water-dispersibility is only achieved by full neutralization of the ionizable carboxyl groups, then full neutralization is necessary.
In the examples illustrating the use of the compo-sition of the present invention as paints, the paint is spray-ed on certain steel panels and then baked. In certain in-stances, however, one could utilize the composition of the present invention in electrodeposition coatings on metal pan-els, such as steel panels, and Example 3, as set forth here-inabove, is illustrative of a type of resin composition that could be made readily adaptable to such use.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A stable water-dispersible composition of matter comprising a blend of (A) from about 15% to about 85%, by weight, of a non-ionic polyether polyol resin having only carbon, hydrogen and oxygen atoms and optionally a halogen atom, having an average molecular weight between about 300 and 4,000, having at least two alcoholic hydroxy groups and not less than about 20%, by weight, of hydrophobic moieties derived at least in part from aromatic or cycloaliphatic materials and correspondingly not more than about 80%, by weight, of hydrophilic moieties consisting of -(CH2CH2-0-) units; (B) correspondingly from about 85% to about 15%, by weight, of a water-dispersible, non-gelled, anionic vinyl polymer having a molecular weight between about 5,000 and 100,000 and having pendant carboxyl groups, in an amount ranging be-tween about 0.40 gram mol to 4.00 gram mols per 1,000 grams of polymer; and (C) from about 10% to about 50%, by weight, based on the total weight of (A) and (B) of a compatible aminoplast cross-linking agent having an average molecular weight not greater than about 1,500, wherein said vinyl polymer is prepared in bulk or solution polymerization.

2. A composition according to claim 1 in which the cross-linking agent (C) is alkylated with a C1-C4 alkanol.

3. A composition according to claim 1 in which (C) is an alkylated C1-C4 urea-formaldehyde cross-linking agent.

4. A composition according to claim 1 in which (C) is an alkylated C1-C4 melamine-formaldehyde cross-linking agent.

5. A composition according to claim 1 in which (C) is an alkylated C1-C4 benzoguanamine-formaldehyde cross-linking agent.

6. A composition according to claim 4 in which (C) is hexakis (methoxymethyl) melamine.

7. A composition according to claim 5 in which (C) is diethoxydi-methoxymethyl benzoguanamine.

8. A composition according to claim 4 in which (C) is a butylated melamine-formaldehyde cross-linking agent.

9. A composition according to claim 3 in which (C) is a fully methylated urea-formaldehyde cross-linking agent.

10. A composition according to claim 1 in which the polyether polyol (A) is the reaction product of 4,4'-methylene diphenol and ethylene oxide.

11. A composition according to claim 1 in which the polyether polyol (A) is the reaction product of 4,4'-methylene diphenol and propylene oxide.

12. A composition according to claim 1 in which the polyether polyol (A) is the reaction product of 4,4'-isopropylidene diphenol and ethylene oxide.

13. A composition according to claim 1 in which the polyether polyol (A) is the reaction product of 4,4'-isopropylidene diphenol and propylene oxide.

14. A composition according to claim 1 in which the polyether polyol (A) is the reaction product of a phenol-formaldehyde resin with ethylene oxide.

15. A composition according to claim 1 in which the polyether polyol (A) is the reaction product of a phenol-formaldehyde resin with propylene oxide.