GB1597610A - Method of water-solubilizing high performance polyether epoxide resins the solubilizing resins and thermoset hydrophobic coatings derived therefrom - Google Patents

Description

(54) METHOD OF WATER-SOLUBILIZING HIGH PERFORMANCE POLYETHER EPOXIDE RESINS, THE SOLUBILIZING RESINS AND THERMOSET, HYDROPHOBIC COATINGS DERIVED THEREFROM (71) We, THE DOW CHEMICAL COMPANY, a Corporation organised and existing under the laws of the State of Delaware, United States of America, of Midland, County of Midland, State of Michigan, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention is a water-thinnable resin composition, a method of preparing it and coatings derived from it.

The composition of the invention is a mixture of base-neutralized reaction products of H3PO4 with polyether epoxides of foregoing formula (a) or (q) and, optionally, any of various other types of mono- or polyfunctional epoxides.

The preferred method of the invention is to react the polyether (Et) and, optionally, other (E2) epoxides with an orthophosphoric acid source material and to neutralize the resulting product with a base which is ammonia or an organic amine, preferably a fugitive organic amine. However, the invention also comprises the method of preparation in which separately prepared E1 and E2 reaction products with phosphoric acid are conbined. If the base is ammonia or a volatile amine, the water-thinned, neutralized resin can be converted to a water-insensitive, high performance, thermoset resin by evaporating the water, heating to disrupt the ammonium salt groups and drive off the ammonia (or amine) and curing.

Conventional curing agents capable of reacting with acidic and/or alcoholic hydroxyl groups may be incorporated with the uncured resin.

The term "volatile" means removable, by heating at ambient pressures, to such an extent as not to have an intolerably detrimental effect upon the rate of curing or on the properties of the cured resin.

The ammonia (or amine) driven off during or subsequent to evaporation of water from the uncured resin can readily be recovered as such or as a non-volatile acid salt, by known methods.

The coatings of the invention are those formed on various substrates (preferably metallic) from aqueous dispersions of the preceding compositions.

The preferred method of the invention is more precisely definable as the process for preparing water-thinnable, base-salified reaction products of orthophosphoric acid and polyether epoxides which comprises: (I) reacting orthophosphoric acid with (1) a polyether epoxide resin E1 consisting essentially of molecules, each of which is of the formula:

or of the formula

wherein Q, independently, in each occurrence, is

n is an integer of from 0 to 40, r is zero, 1 or 2 and, independently in each occurrence; R1 is H, methyl or ethyl, R2 is -Br, -Cl or a Cl to C4 alkyl or alkenyl group, R3 is a C1-C4 alkylene or alkenylene group, Y C(CF3)2, -CO, SO2, -S-, -0- or a valence bond, and R4 is -Br, -Cl or a Ct to C4 alkyl or alkenyl group, R20 is H or alkyl of 1 to 12 carbons; and optionally, (2) E2, a vicinal epoxide, other than one of formula (a) or (q), which has an EEW (epoxide equivalent weight) within the range of from 90 to 2000 and is convertible to a water-dispersible material by reaction with orthophosphoric acid and neutralization with a base, said reaction being carried out by contacting E' and, optionally, E2 with an orthophosphoric acid source material and from 0 to 25 molecular proportions of water per molecular proportion of H3PO4 provided by said source material until the fraction of the oxirane groups in E1 and, optionally, E2 converted is at least sufficient to render the resulting mixed product water-thinnable when contacted with a base, the amount of orthophosphoric acid included as such in said source material, or obtainable therefrom by hydrolysis, being such as to provide at least 0.3 P-OH groups per oxirane group, and the mole ratio of E1 to E2 epoxides being from 0.1 to 100 when E2 is present, and (II) contacting the resulting reaction product with at least enough of a base which is ammonia or an organic amine to render it water-thinnable.

In one aspect, the composition of the invention is a resinous mixture produced by the reaction of phosphoric acid and El and, optionally, E2, as above defined, which is water-thinnable when neutralized with ammonia or an organic amine.

In another aspect, the composition of the invention is the water-thinnable product obtained by contacting said resinous products with a ammonia or an organic amine.

Aqueous dispersions of the neutralized products constitute a preferred embodiment of the composition of the invention.

The neutralized, epoxide/acid reaction products of the present invention may be more precisely defined as a water-thinnable, resinous phosphate composition comprising: (A) resin molecules containing 1,2 - glycol- or beta-hydroxy phosphomonoester groups which are derived from the conversion of the oxirane groups in an E1 epoxide represented by one of formulas (a) and (q), the average EEW of the epoxide molecules from which the resin molecules are derivable being from 172 to 5500, optionally, other molecules containing 1,2 - glycol- or betahydroxy phosphomonoester groups which are derived from the conversion of the oxirane groups in E2, a vicinal epoxide other than those of formulas (a) and (q) having an EEW within the range of from 90 to 2000, the mole ratio of said Et- derived molecules to said E2-derived molecules being within the range of from 0.1 to 100, and the number ratio of glycol to monoester groups in each of said types of molecules preferably being within the range of from zero to 18; (B) from 0 to 85 parts by weight of ortho phosphoric acid (H3PO4) per 100 parts by weight of said Et- and E2-derived molecules; and (C) one or more of ammonia or an organic amine in such amount that at least enough of the P-OH moieties in said E1 and E2-derived molecules are salified thereby to render them dispersible together in water.

In a preferred type of the preceding composition, those molecules not derived from epoxides of formula (a) or (q) are derived from E2 epoxides, as above defined, which comprise benzene rings substituted with methylol or lower alkoxymethyl groups (i.e., R-O-CH2- groups in which R is an alkyl group of 1 to 4 carbons or an alkenyl group of 2 to 4 carbons).

In another preferred type of the preceding composition, the molecules not derived from an E1 epoxide are derived from an E2 epoxide consisting of epoxy novolac molecules.

As employed herein, the term "water-thinnable" means that the product so designated forms an essentially homogeneous solution or dispersion, upon being diluted with a substantial proportion of water, and the resulting dispersed product does not "settle out" or otherwise detrimentally alter at such a high rate that the dispersion is impracticable for use as a coating.

The mixtures which constitute the composition may be formed in either of two ways. The E1 and E2 epoxides may be co-reacted with a phosphoric acid source material or the products obtained by separately reacting the epoxides may be mixed (before or after neutralization with the same or different bases).

The latter mode of preparing the compositions is considered as another (process) aspect or embodiment of the present invention. That is, the invention also comprises combining separately formed Et/H3PO4 and E2/H3PO4 reaction products and sufficient base to render the combination dispersible in water.

The following embodiments of the invention are most preferred as having particular merit for coating applications: (1) The product of the foregoing process wherein E1 is a diglycidyl ether, as defined in formula (a) above, derived from adductive polymerization of bis-phenol A with a diglycidyl ether of bis-phenol-A, i.e. wherein R is CH3-C-CH3 and r is zero.

(2) A product of embodiment (1) which has been made water-thinnable by neutralization with ammonia or an amine; (3) The neutralized product of embodiment (2) when thinned with water to a resin content of 50 wt% or less.

(4) A thermoset resin coating prepared from the water-thinned product of embodiment (3).

(5) The product of the foregoing broadly defined process wherein E1 has an EEW of less than 3200.

(6) The embodiment of the foregoing broadly defined process in which the overall ratio of acidic hydroxyls to oxirane groups is within the range of from 0.4 to 1.0.

(7) The embodiment of the foregoing process in which the amount of H3PO4 provided to the reaction is 1 part or less by weight per 100 parts of E (8) The embodiment of the foregoing broadly defined process wherein the phosphoric acid is charged to the reaction as 70 to 90 wt%, aqueous, H3PO4.

The cured resin of embodiment (4) above may be derived from an aqueous composition of the invention in which the water-thinned, neutralized epoxide/H3PO4 reaction product is the sole resinous component or from similar compositions in which other water-dispersible resins, reactive diluents and/or curing agents are also present. In either case, curing may be catalyzed by such known agencies as chemicals, ultrasonic vibrations, heat, high energy wave or particle radiation.

The E1 type of epoxides represented by formula (a) may all be described as resins. A few of the lower epoxides, such as the diglycidyl ether of bisphenol-A, are available as pure, crystalline solids. However, most DGEBA-type epoxides are not ordinarily available as pure compounds, as a consequence of the practical methods employed in their manufacture. Thus, DER-3318, a less expensive form of the diglycidyl ether of bisphenol-A, is prepared through a two-step reaction of epichlorohydrin with bisphenol-A. The product of this reaction includes not only the desired diether but also (in minor amounts) by-products such as

The presence of such impurities, of the types and in the amounts ordinarily present have no substantial deleterious effect in the products of the present invention.

Any of the epoxides of formula (a) having an EEW of less than 5500 can be prereacted with a phenol (as above defined), in such amount as to convert that epoxide to a resin having an EEW not in excess of 5500 and comprising a corresponding proportion of product molecules representable by formula (2).

The reaction is usually carried out by dissolving the E1 epoxide(s) in the medium (when such is employed), adding the acid source material and such water as may be required to utilize that material or to give the desired product composition, and refluxing the mixture at a preselected temperature (and pressure) until the desired degree of oxirane conversion has been attained. The reaction mixture is cooled, neutralized with the base selected, diluted with water (often in an amount equal to the weight of solids present) and stripped.

Phosphoric acid source materials which may be employed in the E1/acid reaction include 100% orthophosphoric acid, the semi-hydrate 2H3PO4. H2O and aqueous solutions containing at least 18 wt% H3PO4 (1 mole H3PO4 per 25 moles of water). The various condensed forms (polymeric, partial anhydrides) of phosphoric acid, e.g., pyrophosphoric acid and triphosphoric acid may also be used.

When the acid source material is of the condensed type, sufficient water should be supplied, at some stage prior to curing the resinous end-product, to ensure that no substantial proportion of P-O-P links are left in the cured resin.

Ordinarily, aqueous phosphoric acid solutions, particularly 7090% solutions, will be preferred. When a condensed form of phosphoric acid is utilized as the source material, the stage in the process at which P-O-P hydrolysis is effected will depend on whether or not minimization of water content during the reaction is desired. If a condensed source material is to be fully utilized as H3PO4 in the reaction, sufficient time should be allowed for complete P-O-P hydrolysis to occur.

The epoxide/acid reaction can be carried out with the neat reactants but it is preferred to employ an effectively inert reaction medium. Exemplary of solvents which are suitable for this purpose, in order of decreasing preference, are the following: (1) mixtures of acetone with methylene chloride comprising 25 or less weight percent of the latter solvent, (2) ketones such as acetone and methyl ethyl ketone, (3) cyclic ethers such as dioxane, (4) linear ethers, such as glycol ethers, (5) esters, such as lower alkyl acetates, (6) mixtures of lower alcohols and chlorocarbons such as methylene chloride, (7) lower alcohols, and (8) chlorocarbons, such as methylene chloride.

The parameters which predominantly determine the water-thinnability of the (neutralized) E1/acid reaction product are the EEW of the E1 epoxide, the P-OH to oxirane ratio, the water to P-OH (H3PO4) ratio, the solubility of water in the reaction medium, temperature and contact time.

To be water-thinnable, when neutralized, the reaction product must have at least a minimal content of phosphomonoester groups and this imposes an upper limit of 5500 on the EEW of the E1 epoxide and a lower limit of 0.3 on the ratio of P-OH groups (provided by the acid source material) to oxirane groups. It is also desirable to water-thinnability that the ratio of glycol groups (from adduction of water with oxirane groups or hydrolysis of phosphodiester groups) to phosphomonoester groups is not higher than 18 to 1. This in turn requires that the mole ratio of water to H3PO4 in the reactants is not higher than 25 to 1.

The extent to which water enters in to the reaction depends not only on the water to acid ratio but also on the activity of the water, which in turn depends both on the nature of the reaction solvent and the temperature. As a general rule, the activity of the water will be lower in poor solvents for water and at lower temperatures.

Adduction of P-OH with oxirane groups appears to proceed fairly rapidly in less polar solvents and, in such solvents, formation of ,B,A' - dihydroxy phosphodiester groups

occurs to a substantial extent, at least in the early stages of the reaction. If water is absent or has a low activity in the solvent, the oxiranes may be predominantly converted to such diester groups and the E' molecules may be linked together by the diester groups to such an extent that gelling results.

The diester groups are readily hydrolyzed (to "glycol" and monoester groups) and therefore generally do not constitute an important component of the final products derived from reaction mixtures in which the activity of water is substantial.

Furthermore, in the more polar solvents, acid-catalyzed adduction of water with oxirane groups appears to compete quite effectively with P-OH adduction.

Both adduction and hydrolysis reactions of course proceed more rapidly at higher temperatures and shorter contact times are accordingly required to attain a desired degree of oxirane conversion or to reach an equilibrium condition. If the activity of the water present is markedly higher at a more elevated temperature, the proportion of "glycol" groups in the product may increase accordingly.

As a consequence of oxirane conversion directly to glycol groups, free H3PO4 will generally be present in the reaction product, even when the P-OH to oxirane ratio in the reactants was substantially ess than 1. However, the presence of the free acid (as a base salt) in the neutralized product does not ordinarily have a serious detrimental effect on the dispersibility of the product in water. Thus, a water dispersible product can be obtained in some cases even when the amount of the acid source material employed in the reaction is so high that as much as 85 parts by weight of H3PO4 per 100 parts of the E' derived resin molecules will be present in the product. However, such high acid contents result in poor hydrolytic stability in the cured coating. Of course, high acid contents can be lowered to tolerable levels by extraction, preferably before the product is neutralized.

The water-thinnability of the E'/acid product has been found sensitive to the nature of the solvent it is associated with when the neutralized and water-diluted reaction mixture is stripped. The reaction solvent best suited to formation of a product of a desired composition may not be the best medium from which to form the aqueous dispersion. However, the reaction mixture may be stripped before (or even after) neutralization and dilution with water and replaced by a more suitable solvent. Methyl ethyl ketone has been found advantageous for the latter purpose.

Alternatively, by using acetone including a minor proportion of methylene chloride as the solvent, very good results are obtained both in the reaction and the dispersion steps.

Preferred reactant ratios and conditions for the E'/acid reaction are as follows: acid source material, aqueous 70% to 90% H3PO4; amount of acid source material, such as to provide from 0.8 to 1.2 P-OH's per oxirane; reaction temperature, within the range of from 1 10" to 130"C; and contact time, within the range of from 3 to 6 hours. Supra-atmospheric pressures, at least equal to the autogenous pressure of the reaction mixture, of course must be maintained at temperatures above the boiling point of the solvent at atmospheric pressure. (Temperature of up to about 150"C may be employed.) The foregoing summary is generally applicable to the reaction of E2 epoxides with phosphoric acid source materials to form products which will be water- thinnable when neutralized. It is also generally applicable to co-reactions of E' and E2 epoxides with H3PO4 (etc.). However, it is desirable to employ lower reaction temperatures (and/or to moderate the reaction in other ways) when the epoxide (E2 or E') tends to readily polymerize and/or is substituted with such inherently reactive functions as methylol- or lower alkoxymethyl groups.

It may also be noted that most of the E2-type epoxides which will be used have substantially lower EEW's than the most important E' epoxides (those for which the average value of n, in formula (a) or (q), is 9 or more). Consequently, it may not always be necessary to stay within the various ratio limits set out above for the E1/acid reaction and products, when using an E2 epoxide alone. In general, however, the best dispersions, of E2 products or of mixed E1 and E2 products, will be obtained by staying within those limits.

The base constituent of the neutralized, mixed E1 and E2 acid reaction products preferably consists of one or more fugitive bases. That is, those bases present are volatile and dissociate from the acid (free acid or phosphoester P-OH) groups upon heating the salified product to a temperature equal to or lower than the required cure temperature (but higher than the maximum kettle temperature attained during stripping). Ammonia and amines are exemplary of such fugitive bases. The preferred bases are amines, particularly those of the formula NR3, wherein each R is H, methyl or ethyl, independently, except that not more than one R is H. The most preferred base is triethylamine.

To facilitate understanding of the further discussion of the present process invention that follows herein, the natures of the E1 and E2 epoxides employed will first be disclosed in greater detail.

Suitable E1 epoxides for the practice of the present invention are defined by formulas (a) and (q) earlier herein. Preferred among such epoxides are those in which Q, in all occurrences, is

i.e., E' is preferably a nominally difunctional epoxide of the formula

or a nominally monofunctional monoepoxide derivable therefrom by 1:1 adduction with a phenol of the formula

wherein R2, r and R20 are as above defined.

Particularly preferred are E' epoxides of the foregoing formulas in which Q, in essentially all occurrences, is either

Most preferred are E' epoxides in which Q, in essentially all occurrences, is

The individual epoxide of the foregoing type presently considered to be best for the practice of the invention is DER(9-667 (or equivalent DGEBA resins for which n (in formula (a)) is within the range of from 10 to 13 (EEW from 1500 to 2000).

The most widely used resins of the foregoing type are DGEBA (diglycidyl ether/bis-phenol-A) resins, i.e., polyether diepoxides derivable from the polymeric adduction of bisphenol-A

with the diglycidyl ether of bisphenol-A

The diglycidyl ether may be preformed by reacting two molecules of epichlorohydrin with one molecule of the bisphenol-A in the presence of a base, such as sodium hydroxide. Classically, however, the latter reaction is carried out in such a manner that the resulting di-ether molecules react in-situ with bisphenol molecules to produce the DGEBA resin.

In the latter case, the reaction product tends to be a mixture consisting predominantly of polymeric species of different molecular weights corresponding to different values of n in the following idealized formula:

By reason of including some monofunctional epoxide species, such mixtures exhibit average epoxide functionalities of somewhat less than two.

The epoxide equivalent weights given subsequently in the examples herein for the preceding types of epoxides are generally somewhat higher than the theoretical values for the nominal compounds, for the reasons explained above.

The practice of the present invention is not restricted to the use of one type of E1 epoxide at a time or to such epoxides in which all R1, R2, R3 or R20 groups are the same throughout the molecule. Two or more distinct E1 epoxides may be combined in a single reaction product with phosphoric acid. Similarly, a given E1 epoxide may comprise as many different kinds of R1 groups (H, -CH3 or -C2H5), R2 or R4 groups (-Br, -C or -CH3), R3 groups (C1-C4 alkyl or alkylene, SO2 or +) or R20 groups (H or C1C12 alkyl) as it is synthetically feasible to incorporate in individual molecules of the formulas given in the foregoing broad definition of the invention.

Thus, for example, polyether diepoxides may be formed by using a mixture of epichlorohydrin and methylepichlorohydrin in place of either chlorohydrin alone, in well known methods of synthesis, such as are described in Handbook of Epoxy Resins; (ch. 2) Lee and Neville; McGraw-Hill, (1967). Similarly, mixtures of different bisphenols may be employed in well known procedures for reacting an individual bisphenol with an epichlorohydrin or with a diglycidyl ether of the same or a different bisphenol.

Few, if any, commercially available DGEBA-type resins are derived from bisphenols other than bisphenol-A (as such, or substituted with bromine or chlorine) or from chlorohydrins other than epichlorohydrin itself. That is, the commercially available DGEBA-type resins are those of the preceding general formula for E1 in which R1 is H, r is either 0 or is 2 and R2 is Br or Cl, and R3 is (CH3)2C Exemplary of such commercial DGEBA resins, which are preferred for the practice of the present invention, are the following (manufactured by The Dow Chemical Company): TABLE A Viscosity; Theoretical cps @ 250C Value of n or Corresponding to (Duran mp.) Designation M =2xEEW EEW C DERR -332 0 172-6 4000-5000 -331 0 186-92 11,000-14,000 -542 0 330-80 (51-61 ) -337 ~0.5 230-50 semi-solid -660 ~2 425-75 (65-74) -661 2-3 475-575 (70-80) -662 3-4 575-700 (80-90) -664 5-6 875-975 (90-105) -667 10-13 1600-2000 (113-123) -668 13-23 2000-3500 (120-140) -669 23-38 3500-5500 (135-155) -684 ~90 ~13,000 Notes: 1 Epoxide Equivalent Wt.

2 Prepared from tetrabromo-bisphenol-A 3 Molecular Weight.

The epoxide functionality of DGEBA resins is generally less than the theoretical value of 2 and the actual values of n for the resins listed above would be lower than the theoretical values calculated for molecular weights equal to twice the EEW's given.

According to Lee & Neville (loc cit), a typical DGEBA resin having an EEW of about 190 (theoretical value of n=0) has been found to consist about 88% of molecules in which n=0, 10% of n=l and 2% of n=2. Similarly, a typical higher molecular weight DGEBA resin, such as is used in some solution coatings and having an EEW of about 540 (theroetical value of n=2) was found to have the following compositions: > 50% of n=3-5; about 15% of n=2; 15% of n=l, and 20% of n=4.

Exemplary bisphenols from which E epoxides of the general formula (a) given earlier herein may be prepared, are as follows: mononuclear dihydric phenols

dinuclear bisphenols

Bisphenol-F Bisphenol-A Dichloro Bisphenol-A Tetrabromo Bisphenol-A Additional exemplary bisphenols will be found in Tables I and II: The Chemistry of Phenolic Resins: R. W. Martin; pp. 6479, Wiley & Sons; N.Y., N.Y., (1956).

E' epoxides of the type represented by formula (q) may readily be prepared by "capping" corresponding epoxides of formula (a), with one or more phenols

R2, r and R20 being as defined earlier herein, in a manner familiar to those skilled in the epoxy resin art. It has been found that the wetting ability of the resin can be varied in this manner to ensure better wetting on a given type of substrate.

It will of course be recognized that formula (q) will only be representative of the capped product as an "average" structure. That is, even if the phenol and type (a) epoxide are reacted in equimolar proportions, some of the product molecules will not be capped and others will have had both oxiranes reacted out. The epoxide and the phenol can be reacted in other than 1 to 1 ratio, so long as the EEW of the product is not raised above 5500.

Suitable E2 epoxides for the practice of the present invention are vicinal epoxides, other than those of the preceding formulas (a) and (q), which have EEW's within the range of from 90 to 2000 and are convertible to water-dispersible products by reaction with orthophosphoric acid, followed by neutralization with a base. Those skilled in the art, with the guidance afforded by these specifications, will be readily able to determine whether the latter criterion is met by any given candidate epoxide.

Representative kinds of E2 epoxides are mono- to penta-functional epoxides of types (b) through (p), following: (b) a methylol- or alkoxymethyl-substituted phenylglycidyl ether of the following formula

wherein Y is H or a C, to C4 alkyl or alkenyl group, each YO-CH2- group is either ortho or para to a glycidyloxy group, x is 1, 2 or 3, p is 0 or I and a is 1 or 2, Rt, independently in each occurrence, is H, methyl or ethyl, R5 is a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, alkylphenyl, phenalkyl, phenoxy, -Br, -Cl group or a

group, wherein y is 0, 1 or 2 Y and R are as above defined, T is a C1-C4 alkylene or alkenylene group, C(CF3)2,-SO2-, -S-, -O- or a valence bond, R6 is -Br, -Cl or a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, alkylphenyl, phenalkyl or phenoxy group, and t is 0 or 1; with the proviso that (x+a) cannot exceed 4 (x+y) is from 2 to 4; (c) a methylol- or alkoxymethyl-substituted, (2,3 - epoxy)propylbenzene of the formula

wherein: b is 1 to 3, d is 0 or 1, R7 is C1-C12 alkyl or

Y' is H or a C1 to C4 alkyl or alkenyl gr

wherein, R is -H, -CH3 or -C2H5, R10 is -H or -CH3, X is -H, -CH3 or -C2H5, g is 1, 2 or 3 and h is an integer of from 2 to 10; (h) diglycidyl ethers or esters of the formula

wherein R11 is a divalent hydrocarbon radical of from 2 to 20 carbons, R is -H, -CH3 or -C2H5 and i and j independently are 0 or 1; (i) mono or diglycidyl ethers of

(j) mono-, di- or triglycidyl ethers of glycerine; (k) trifunctional aromatic epoxides

wherein Z is

R12 is C1-C2 alkoxy, C1-C6 alkyl or C2-C6 alkenyl, R13 is H, C1-C12 alkyl or C2-C12 alkenyl, R14 is a C1-C6 alkyl, alkenyl, cycloalkyl, cyloalkenyl or aralkyl group, ortho or para to those Z-CH2- moieties on the benzene ring to which said group is attached, R is as previously defined and R15 is a C1-C4 alkylene or alkenylene group or (l) tetraglycidyl ethers of the formula

wherein Rl6 is a C1 to C6, divalent aliphatic hydrocarbon radical,

C(CF3)2, -SO2-, -S-, -O- or a valence bond and

(m) tri- to pentafunctional epoxy novolaks of the formula

wherein p is 1 to 3, Rl7 is H or -CR3, independently in each occurrence, R'8 is an alkylene group of 1 to 4 carbons and

(n) methylol substituted, oligomeric monoepoxides of the formula

wherein u is 0, 1, 2 or 3, R', independently in each occurrence, is H, methyl or ethyl and R19, independently in each occurrence, is a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, phenalkyl or alkylphenyl group; (o) epoxidized triglycerides of unsaturated fatty acids of up to 18 carbons each; and (p) one to one adducts of substituted phenols with diglycidyl ethers of substituted bis-phenols, of the formula

wherein Rl, R2, R3 and r are as defined in preceding formula (a), Y, R5 and p are as above defined in formula (b), v is 1, 2 or 3 and w, independently in each occurrence, is 0, 1 or 2.

Exemplary, specific E2 epoxides of types (d) through (m), and (o), are as follows: Type Epoxide (d) Butadiene diepoxide, limonene dioxide, linaloöl dioxide, 4 vinylcyclohexene dioxide and trivinylbenzene trioxide. (See also Example 13.) (e) Diglycidyl ether, 4,4' - divinyldiphenylether dioxide, bis(2,3 epoxycyclopentyl)ether and the glycidyl ether of 3,4 - epoxy - 1 butanol.

(f) Glycidol, epibromohydrin, 2 - methyl epichlorohydrin, glycidyl benzoate and glycidyl methacrylate.

(g) The monoglycidyl ether of ethylene glycol and the bis(2 methylglycidyl)ether of tripropylene glycol.

(h) Ethylene glycol diglycidyl ether, 2 - butene - 1,4 - diol, diglycidyl ether; and the bis(2 - ethylglycidyl)ether of 1,1 - dimethylol - 3 - cyclohexene.

(i) 2 - glycidyloxymethyl - 5 - hydroxymethyl - tetrahydrofuran and the bis(2 - methylglycidyl)ether of 2,6-dioxane diol.

(k) 1,3,5 - tris(glycidyloxy)benzene, 2,6 - diglycidylphenyl glycidyl ether, tris(4 - glycidyloxyphenyl)methane, 2,2',4' - tris(2 methylglycidyloxy)diphenyl, and

(1) 2,2',4,4' - tetrakis(glycidyloxy)diphenylmethane.

(The penta-glycidyl ether of the condensation product of 5 molecules of phenol with 4 molecules of acetone.) (o) Epoxide molecules of this type constitute the reactive components of epoxidized Soybean oil. A commercial version of this material (Flexol- EPO; Union Carbide Corp.) is an epoxidized mixture of triglycerides of Cl4 to Cl8 fatty acids. The proportions of saturated and unsaturated acids in the oil (prior to epoxidation) are as follows: Fatty Acid Formula Wt % # of C=C M ristic C,4H2802 .1 0 Palmitic C16H32O2 8.0 0 Stearic C,8H3802 4.0 0 Arachidic C20H40O2 .6 0 Myristoleic C,4H2602 .1 1 Palmitoleic C16H3002 .2 1 Oleic C18H34O2 28.0 1 Linoleic C18H32O2 54.0 2 Linolenic C18H30O2 5.0 3 The theoretical EEW for epoxidation of all double bonds in the oil is about 210.

Types (b), (c), (d), (g), (m), (n), (o) and (p) are preferred among the above listed kinds of E2 epoxides. Within the latter group, types (b), (c), (n) and (p) are particularly preferred by reason of containing methylol or lower alkoxymethyl substituents which render rapidly heat-converting those E'/E21H3PO4 product mixtures comprising them.

Epoxides of types (d), (g), and (o) have been shown to improve film formation, dried film adherence and/or cured film flexibility. An epoxide of type (m) has been shown to improve film formation, curred film adhesion and solvent resistance (but to reduce cured film flexibility.

Most preferred E2 epoxides are those of formula (b) in which Y is H or -CH3, x=z, p=l, and R5 is an aliphatic hydrocarbyl group of 1 to 12 carbons.

Exemplary epoxides of formula (b) which can be employed in the process of the invention are those methylol-substituted glycidyloxybenzene compounds derivable from the following known methylol-substituted phenols and bisphenols by known methods (see, for example, U.S.P. 3,859,255; columns 5-7):

Q=Br, methyl, ethyl, propyl, isopropyl, n - butyl, t - butyl or nonyl;

A specific, methylol-substituted, mononuclear diepoxide (of formula (b)), disclosed in U.S.P. 3,925,315 is

Specific dinuclear type (b) diepoxides are the following "Apocen" resins, available from Schaefer Chemicals, Inc., P.O. Box 132, Riverton, New Jersey:

Mixed glycidyl ethers of mono-, di- and trimethylol phenol can be prepared by "expoxidation" of the corresponding mixture of allyl ethers, which is marketed as MethylonB Resin 75108 by General Electric Company. (See U.S.P. 2,965,607 for an epoxidation procedure.) These mixed ethers are representative of type (b) mononuclear, monoepoxides substituted with from 1 to 3 methylol groups.

Exemplary E2 epoxides of foregoing formula (c) are:

which can be made by the "epoxidation" procedure of Example XII, U.S.P.

2,965,607, from the respective precursor compounds, 1 - allyl- 2,4,6trimethylolbenzene (U.S.P. 3,906,126) and 1 - allyl - 2 - methoxy - 3,5 dimethylolbenzene (U.S.P. 2,707,715).

Some or all of the methylol groups present in epoxypropyl benzene compounds of the preceding types, or in the glycidyl ethers derivable from any of the foregoing methylol-substituted phenols, can be converted to corresponding alkoxymethyl groups by well known methods commonly utilized in making benzyl ethers.

Epoxides of formula (n) may be regarded as oligomers of methylol-substituted phenyl glycidyl ethers. They may be prepared simply by heating the latter ethers to a temperature (such as about 165"C) at which the methylol groups interact with the oxirane groups at a reasonable rate and maintaining that temperature until the EEW of the resin has increased to a value commensurate with the desired value of u.

The specific oligomer in which (in formula (n)) the average value of u is about 1.5, R' is H and R'9 is t - butyl, has an EEW of about 940 and is obtained by heating the corresponding monomer for about 2.3 hours at 1650C.

Some or all of the residual methylol groups in such oligomers of course can be converted, by known methods, to alkoxymethyl groups to provide a variant type of E2 epoxide.

Exemplary epoxides of formula (p) are:

which can be prepared by reaction of the corresponding 4 - alkyl - 2,6 dimethylolphenols and diglycidyl ethers of bis-A-type diphenols in the presence of a catalyst, such as ethyltriphenylphosphonium acetate, in a known manner.

The practice of the present invention is not restricted to the use of one species of E2 epoxide at a time or to such epoxides in which all Y, R', R2, R3, R6, Z (etc.) groups are the same throughout the molecule. Two or more distinct E2 epoxides of any or all of preceding formulas (b) through (p) may be combined in a single reaction product with phosphoric acid. A given epoxide may comprise as many different kinds of the specified substituent groups as it is synthetically feasible to incorporate in individual molecules of the latter formulas.

When the mixtures of the present invention are to be made by co-reaction of a phosphoric acid source material with an E1 and an E2 epoxide, the reaction may be carried out in either of two ways. The E' and E2 epoxides may be mixed and then contacted with the acid, or first one and then the other of the two types of epoxides may be "reacted in". It might be expected that the second mode of practice would result in the presence in the final product of molecules consisting of E' and E2 residues joined by phosphodiester groups. However, this generally will only be the case if water is essentially excluded from the mixture and any free acid remaining after the first reaction has been removed before the second epoxide is added.

Further, any such diester groups will tend to undergo hydrolysis whenever the product is contacted with water.

In general, it has been found preferable to react the acid with the E' and E2 epoxides sequentially. When this is done, different reaction temperatures may be employed for the successive conversions of the two types of epoxides. As a rule, the E2 epoxide will be the more reactive of the two and is best introduced after the E' epoxide has been at least partly converted.

Phosphoric acid source materials which may be employed in the practice of the present invention include 100% orthophosphoric acid, the semi-hydrate 2H3PO4. H2O and aqueous solutions containing at least 18 wt% H3PO4 (1 mole H3PO4 per 25 moles of water). The various condensed forms (polymeric, partial anhydrides) of phosphoric acid, pyrophosphoric acid and triphosphoric acid may also be used.

When the acid source material is of the condensed type, sufficient water should be supplied, at some stage prior to curing the resinous end-product, to ensure that no substantial proportion of P-O-P links are left in the cured resin.

Ordinarily, aqueous phosphoric acid solutions, particularly 7090 /O solutions, will be preferred. When a condensed form of phosphoric acid is utilized as the source material, the stage in the process at which P-O-P hydrolysis is effected will depend on whether or not minimization of water content during the reaction is desired. If a condensed source material is to be fully utilized as H3PO4 in the reaction, sufficient time should be allowed for complete P-O-P hydrolysis to occur.

The rate at which the oxirane groups are converted in the E'/H3PO4 reaction and the makeup of the products obtained are of course dependent on such parameters as water to acid ratio, acid to oxirane ratio, solvent nature, temperature and contact time.

It has been found that the reaction generally involves more than just adduction of P-OH with oxirane groups. Unless pains are taken to ensure the absence of water in the reaction mixture, the product will generally include substantial proportions of molecules in which at least one oxirane group has been converted to an alpha, beta-dihydoxy group, i.e., a "glycol" group. This apparently results not only from H±catalyzed adduction of water with oxiranes but also from phosphodiester group hydrolysis. As a consequence of the former reaction, some free phosphoric acid will generally be present in the reaction product, even when the amount of acid used is such as to provide substantially less than one P-OH per oxirane group.

It is apparent that the presence of water has a more profound effect on the composition of epoxide/H3PO4 reaction products than has heretofore been realized.

Introduction ofwater to the reaction mixture may be avoided by use of l000,/o phosphoric acid as the sole acid source material. However, it has been found that esterification of the secondary alcoholic hydroxyl groups in DGEBA type epoxides tends to occur to a minor extent. Since water is also produced by this reaction, steps must be taken to scavenge or remove any evolved water if attainment of really low glycol to ester group ratios in the product is desired. This is most readily done by employing some P-O-P group-containing acid source material (such as pyrophosphoric acid or polyphosphoric acid) with the 100% acid. Esterification of alcoholic hydroxyls (and water production) is also minimized by carrying out the reaction at relatively low temperatures (such as 60--800C).

If desired, a suitable P-O-P group-containing acid source material for the latter purpose can be made simply by in-situ, pre-reaction of pyrophosphoric acid with less than the amount of water required to react out all of the P-O-P groups.

Although the presence of (salified) phosphomonoester groups is essential to water-thinnability of the E'/H3PO4 reaction product, it is not necesary that a high proportion of the oxirane groups in E' report in the product as ester groups, rather than as glycol groups. On the contrary, "esterification" products of DER(!)-667 in which the number ratio of glycol to ester groups is as high as 18.3 to 1 have been found to be water-thinnable and to yield useful coatings when cured. (See Example Il herein.) The foregoing finding constitutes a most unexpected and surprising discovery and has important consequences to the suitability of the compositions of the present invention as linings for food containers. One consequence is that the phosphoric acid (and the salifying base) can be used in such minor amounts (as little as 0.75 grams of H3PO4 per hundred grams of DER-667, for example) that the cost of the final product is substantially less than it would otherwise be.

Another consequence is that when a fugitive base is employed, the amount of the base evolved prior to (or during) curing is so small that the problem of recovery is correspondingly reduced. A further, very important consequence is that the amount of the (fugitive) base retained in the cured coatings is essentially nil (within the range of from 50 parts per billion down to undetectable amounts).

The amount of water provided to the acid epoxide reaction can vary from 0 to 25 molecules per molecule of H3PO4 provided by the acid source material.

Amounts of water in excess of about 2--4 moles per mole of the acid will generally result in an inhomogeneous reaction mixture unless a good solvent for water is included therein. The presence of water in relatively high proportions does not necessarily result in as low phosphoester to glycol group ratios in the reaction product as might be expected. Ester to glycol ratios as high as 1 to 2.3 have been obtained (using DER667 as the epoxide and acetone as the reaction medium) at water to acid mole ratios in the vicinity of 25 to 1.

The product resins will generally be water-thinned and it is usually preferable to have water present in the mixture before the solvent is removed. Accordingly, the presence of relatively large amounts of water during the reaction does not pose any large problem on these accounts. It has been found that prolonged reaction times are essential to attainment of high oxirane conversions at higher water concentrations. However, it is highly advantageous to process economics to be able to recycle recovered solvents having substantial water contents. Accordingly, the optimum water content for the reaction of any particular E' epoxide will need to be determined. This will not require undue experimentation and methods for doing it will be made readily apparent by the examples herein.

The amount of acid introduced to the reaction by the acid source material should be such as to provide about 0.3 or more acid hydroxyls (hydroxyl groups attached to phosphorous) per oxirane group present in the E1 epoxide reactant.

Preferably, however, the amount of acid is kept below 1/3 mole of H3PO4 per equivalent weight of E' (i.e., below 1 acidic hydroxyl per oxirane), thereby avoiding substantial decreases in water-resistance of the cured products. When E' is DERV 667 (or an equivalent DGEBA-type epoxide), it is highly preferred that not more than 1 part by weight of H3PO4 be provided per 100 parts of E1.

Greater amounts of acid, up to the point where the reaction mixture becomes undesirably non-homogeneous, may be employed. However, the use of more than enough H3PO4 to provide about 4 acidic hydroxyls per oxirane may result in the inclusion of enough free phosphate salt to have an undesirable effect on the properties of the uncured or cured product resin, thus necessitating removal of at least part of the excess acid-preferably before a base is introduced.

The epoxide/acid reaction can be carried out neat and a reaction medium (solvent) is not necessarily required. However, as discussed earlier herein, the use of a medium is essential to homogeneity of the reaction mixture when the amounts of water and/or H3PO4 present are high relative to the amount of the epoxide.

Better results are obtained when the reaction mixture is homogeneous and it is generally preferable to employ a reaction medium in any case.

Suitable media for the reaction of the present process are inert materials which, in admixture with the reactants, form a solution or dispersion which is fluid at the reactioP temperature to be employed. As employed in the present application, the term "inert" means that the medium does not detrimentally react with any material present to such an extent that at least one of the objects of the present invention cannot be realized.

Preferred media are inert organic compounds or mixtures which are liquid at ordinary temperatures, have boiling points below 1500C and are solvents for the epoxides and phosphoric acid source material(s) to be used. The solvent should also be able to dissolve enough water to ensure that the desired ratio of dissolved water to acid (or oxirane groups) is attained. Exemplary of such media are dioxane, glycol ethers, lower alkyl acetates, methyl ethyl ketone, acetone, ethanol, isopropanol and methylene chloride in an admixture with any of the preceding solvents. (The latter alcohols exemplify "inert" solvents which are not detrimentally reactive to an intolerable extent. They are particularly useful (as cosolvents) when precipitation tends to occur in their absence, as when aqueous H3PO4 is added to a dilute solution of an El resin in a medium comprised solely of dichloromethane.) The nature of the reaction medium effects both reaction rates and product composition. As a general rule, the rate of oxirane conversion by P-OH adduction and the proportion of diester groups in the reaction mixture is higher when a poor solvent for water is employed as the reaction medium.

At a temperature of about 60"C, the poor (or non-) solvents for water favor formation of higher polymer chains made up of E' epoxide residues linked together by diester groups

Thus, if DERdS667 is reacted with 1% of its weight of H3PO4 (as 85% aq. H3PO4) in 100% CH2CI2 at 600C, the reaction mixture gels in about 4 hours. The chemical activity of water in a solvent such as dichloromethane, under these conditions, does not appear to be high enough to result in substantial hydrolysis of oxirane or ester groups. (However, the latter type of gel could be dissolved in a more water-miscible solvent and hydrolyzed to a fully useful product containing about equal numbers of glycol and monoester groups.) If the reaction medium also contains as much as 25 wt percent of CH2CI2miscible solvent for water, such as acetone, diester formation is still the predominant reaction (at 600 C.) but the product is not a gel. At a temperature of 115--120"C., the activity of the water (contained with the H3PO4) in a medium consisting of 75 wt% CH2Cl2 and 25 wt% acetone, is substantial. Diester formation does not proceed as far and hydrolysis of all of those diester groups which are formed occurs. As the proportion of acetone is further increased, however, diester formation drops and the monoester content in the final product increases. Direct adduction of water with oxirane groups apparently is the predominant reaction (at 115--1200C), but the ratio of glycol to monoester groups goes down as the proportion of acetone in the CH2Cl2/acetone mixture increases.

The nature of the medium in which the neutralized reaction product is formed is also important. That is, the medium which serves best for the preparation of a given reaction product is not necessarily the medium from which the most stable or highest solids content dispersion of the neutralized product in water can be obtained.

Thus, tests have shown that although higher monoester contents are obtained from the (above discussed) reactions of DER(b667 with 85% H3PO4 in acetone alone than in acetone/CH2Cl2 solutions, the presence of a minor amount of the dichloromethane is helpful to dispersibility of the neutralized product formed when water is added and the organic medium is removed. It has also been found that, in general, product particles formed upon stripping the neutralized epoxide/acid reaction mixtures exhibit less tendency to agglomerate when derived from solutions in dioxane or methyl ethyl ketone-particularly the latter solvent.

Accordingly these solvents may be employed to particular advantage as media for the preparation of those neutralized acid/epoxide products which are inherently more difficult to disperse in water.

If extractive removal of excess phosphoric acid at any stage prior to neutralization is contemplated, it is of course feasible to include an appropriate amount of a solvent which is not miscible with water, or prone to emulsify therewith, in the reaction medium. Also, solvents which are base sensitive, such as acetone, should first be removed if more than the stoichiometric requirement of base will be employed to effect neutralization.

Mixtures of two or more solvents are in some instances preferred as providing a medium having a desired combination of solvent action and initial or azeotropic boiling point (reflux temperature).

Suitable reaction temperatures range from the lowest temperature at which P-OH adduction with oxirane groups (in the E' epoxide) proceeds at a useful rate to temperatures so elevated that (1) detrimental reactions (as between an alcohol reaction medium and the phosphoric acid) occur to an intolerable extent; or (2) excessively high solvent vapor pressures are developed. Temperatures within the range of from 500C to 1500C will generally be found satisfactory but it is preferred to maintain the reaction temperature within the range of from 70"C to 1350C.

The nature of the interdependence of temperature and solvent effects has been indicated in the preceding discussion herein of reaction media.

Pressure is an important parameter of the reaction only in that operation under elevated pressures-at least equal to the autogenous pressure of the reaction mixture-are required when reaction temperatures above the normal atmospheric boiling point of the reaction medium are employed. The reaction can of course be carried out at sub-atmospheric pressure is desired.

Contact time is an important parameter of the present process only in that the reaction is generally allowed to proceed until less than 1%, and preferably less than 0.5% of the oxirane groups originally present are consumed. It is only necessary to convert as much of the epoxide as is required to produce a reaction product having essentially the character of the more highly reacted epoxide/acid products of the invention. That is, epoxide conversion need be only essentially complete.

In accordance with well known principles, the rates of the several reactions which tend to occur will be higher at more elevated reaction temperatures and shorter contact times will be required at such temperatures.

As a general rule, prolonged contact will tend to result in a higher degree of diester hydrolysis.

In most instances, contact times of from about 1 hour (at temperatures in the vicinity of 150"C) to about 24 hours (at 60--70"C) will be satisfactory. Ordinarily, essentially complete conversion of the E1 epoxide to a product which will be waterthinnable, when neutralized, can be attained in 3-6 hours contact time at a temperature of 125--1000C.

Procedure The reactions of the epoxides with the orthophosphoric acid source materials (and such water as may be present) are readily carried out in conventional equipment.

The first step will normally consist of dissolving the epoxide or epoxides in the reaction medium (or in the component thereof which is the best solvent for the epoxide). In the case of the higher molecular weight (E') epoxides, at least, dissolution in most solvents is somewhat slow at ordinary temperatures and will usually require agitation of the resin/solvent mixture for a period of time such as 8 hours or more.

The acid source material, usually 85% aq. H3PO4, may be pre-dissolved in or diluted with one or more components of the reaction medium, to facilitate mixing with the epoxide solution. In any case, it will usually be more convenient to run the acid material into the epoxide solution, rather than vice versa. Introduction of the reactants to each other gradually and/or at low temperatures is not necessary unless a highly reactive epoxide (more often the E2 epoxide) is employed in the reaction.

(An example of a highly reactive E' epoxide is the diglycidyl ether of bis-phenol-A.) In the latter circumstance, it is desirable to operate initially at as low a temperature as will permit the reaction to proceed at a satisfactory rate. In this manner (and by dilution), reactions leading to gelling can be minimized. Thus, in simultaneous or sequential reactions, the reactants may be inter-mixed as thoroughly as possible, prior to onset of a given reaction, by pre-chilling, mixing and stirring the reactants (and medium) at a low temperature ( < 50C, for example) for a period of up to a day or more. After this is done, the mixture should be allowed to warm slowly, to avoid any tendency for a sudden exotherm to occur.

After the more reactive epoxides have been largely converted, i.e., after the oxirane content has decreased sufficiently, the mixture may be taken to a higher temperature, to drive the reaction(s) to completion more rapidly. However, temperatures substantially in excess of about 150"C generally are to be avoided, during the reaction and also subsequently, as during solvent removal.

Ordinarily, the mixed reactants are heated, preferably with agitation, to the desired reaction temperature in a vessel suitably equipped with a reflux condenser, a pressure seal or such other apparatus as is appropriate. The vessel contents are kept at temperature at least until sufficient oxirane conversion has been attained to result in a water-thinnable product (upon base addition).

The reaction mixture is cooled and then "neutralized" as discussed below, diluted with water and stripped of lower boiling materials. If a reaction medium consisting of or comprising a solvent higher boiling than water has been used for the reaction, addition of water may be delayed until the high boiling solvent(s) have been replaced with a lower boiling solvent (which is then stripped off after the water is added).

It is generally desirable to add the water gradually, with good agitation, as otherwise coagulation of the salified (neutralized) resin may result.

Base Neutralization The reacti which are more highly preferred are N,N- dimethylethanolamine, Nmethylethanoline, ethanolamine and diethanolamine.

Triethanolamine is apparently not suitable for the neutralization of higher molecular weight acid/E' epoxide reaction products of the invention. DER(9- 667/H3PO4 reaction mixtures neutralized with triethanolamine, diluted with water and stripped (to a solids content of about 50%) have not yielded dispersions.

However, triethanolamine does not cause any problems when included with CymelB 303 (hexamethoxymethylmelamine) in coating formulations of the dispersions of the present invention.

It has also been observed that higher molecular weight E'/acid products neutralized with dimethylaminomethylpropanol,

disperse well only if the amount of H3PO4 employed in the acid/epoxide reaction is greater than about 1 part per hundred parts of the resin (DER-667).

Mixtures of any of the foregoing amines and alkanolamines may of course be employed for particular applications where they are of advantage. Similarly, separately prepared E' and E2 reaction products with H3PO4 may be neutralized with different bases and then combined, or may be combined first and neutralized with the same base material.

Neutralization is usually carried out by diluting the acid/epoxide reaction mixture (including the solvent used) with enough water to give a dispersion which is satisfactorily easy t6 stir, and then adding the base (or vice versa). When no acid has been removed from the epoxide/acid reaction mixture, a very convenient method is simply to add 2 equivalents of base (2 moles of an amine, for example) for each mole of H3PO4 (100%) charged to the reaction. However, the amount of base required may be measured out according to a predetermined acid content in the material to be neutralized. Alternatively, litmus or pH paper or a pH meter may be used to determine when to stop adding base. Another option which may be satisfactory in routine operation is simply to add the base, in increments and with good stirring, until the appearance or behavior of the stirring dispersion markedly alters in a way known to correspond to attainment of the desired degree of neutralization. In general, however, a definite pH, within the range of from 6 to 10, (preferably 6.5 to 9) will be preselected as the end-point for the neutralization.

Since the rate of the neutralization will drop off as the number of unneutralized, acidic hydroxyls present decreases, sufficient time should be allowed after each base addition to ensure that any apparent end-point is in fact a true end-point.

Ordinarily, no pH drift should be observable after about an hour.

Water-Thinning and Utilization of the Neutralized H,POdepoxide Reaction Product Unless the neutralized product is to be used without being shipped, as little water as possible will ordinarily be used in preparing it, so that shipping costs will be held down. However, prior to application to a substrate to be coated, the neutralized (and stripped) material will usually be thinned with addition water to a consistency dependent on the amount of additives or curing agents which must be co-dissolved, the mode of application contemplated, the viscosity desired, the thickness of the coating to be formed, and so on. (It is generally preferred to prepare the aqueous product dispersions at a level of 50% solids and no difficulty has been experienced in further thinning such dispersions with water.) Energy requirements for water evaporation are of course another consideration. Ordinarily, the water employed as a thinner will be added at a relatively low rate, which good stirring, so as to avoid any tendency to form a quasi-stable mixture of two discrete liquid phases.

However, in some cases, reverse or even "all at once" addition may be permissible.

Stripping of the neutralized mixture is carried out in a generally conventional manner at a pressure appropriate to the normal boiling point of the solvent(s) to be removed. Care should be taken to avoid excessive kettle temperatures during stripping so that undesired hydrolysis of ester groups does not occur. Undesirably high kettle temperatures are most likely to occur during the latter stages of stripping, particularly when a relatively high boiling, water miscible solvent has been used in or as the reaction medium. In the latter situation, a relatively low stripping rate or some other expedient, such as addition of a solvent which forms a lower boiling azeotrope with the water-miscible solvent, should be resorted to.

In an alternative mode of utilization, the neutralized reaction product may be converted, as by spray-drying, for example, to a powder which can subsequently be dissolved in water or applied directly to substrates by known powder-coating techniques.

Aqueous solutions of the neutralized reaction products can be applied to various substrates to be coated, by such known techniques as spray coating, dipping, roller coating, brushing or by use of draw bars. Removal of the water from the resultant aqueous films is readily accomplished by known methods, such as passing an air stream of controlled temperature and moisture content over the film at a controlled rate, passing the film through a zone of reduced pressure, heating, etc.

When the salt moieties present in the neutralized reaction product (resin) are of such a nature as to be readily decomposed by heating and the base evolved upon decomposition is volatile, all or at least a substantial portion of the base may be removed during the water-removal operation.

Any base remaining after water removal may be essentially removed by further heating, under ordinary or reduced pressure. The removed base ordinarily will be recovered, as by condensation or by acid scrubbing.

As indicated earlier herein, curing of the resin after water and base removal may be accomplished by means of any suitable agency. If an auxiliary chemical curing agent is to be employed, the agent may be introduced prior to water removal or subsequently (as by being sprayed as a solution in a volatile solvent on the uncured film). In general, the most convenient and economical method of curing will be simply by application of heat, as by baking, to effect cross-linking reactions between the reactive functional groups in the deneutralized coating, such as secondary hydroxyls, P-OH groups and any groups reactive therewith, in added curing agents, such as ureas, melamines and phenolics.

Methods of Characterizing Products 1. Titration of Acids The relative amounts of the phosphoric acid charged to the reaction which report in the product mixture as the free acid, as monoester groups and as diester groups may be determined as follows. A sufficient sample of the reaction mixture to provide about 1 millequivalent (meq) of solids (based on acid present) is dissolved in 35 rhI of a solvent consisting of 66.7 wt% 2 - butanone, 16.65% methanol and 16.65% water. The solution is titrated with about 0.3N methanolic tetrabutylammonium hydroxide, using a Metrohm (Registered Trade Mark) Herisan automatic titrimeter, to a second break (inflection) in the resulting conductivity vs. titrant-volume curve. 10 ml of water and 10 ml of 10% aq. CaC12 are added and allowed to react for about 10 minutes, thereby converting all phosphomono- and diester groups to neutral calcium salt groups. The free phosphoric acid is converted to the monoacidic phosphate, CaHPO4. All of the calcium-containing products precipitate but a third break on the titration curve can now be observed, without interference from the second monoester proton, upon neutralization of the proton in the CaHPO4 with more of the quaternary hydroxide base. The amount of base required to produce the first break is that consumed by the sole acidic proton in the diester and by the first protons in the monoester groups and the free acid. The additional amount of base required to reach the second break is that consumed by the second (last) proton in the monoester groups and by the second proton in the free acid. The additional amount of base to reach the last break is consumed solely by the last proton in the calcium salt derived from the free acid. If the total volumes of base solution required to reach the successive breaks are denoted as v1, v2 and v3, the relative amounts of phosphate present as mono- and diester groups and as the free acid may be calculated from the following relationships: Free H3PO4 =v3-v2 Monoester =2 v2-v1-v3 Diester =2 v1-v2 The proportion of the consumed epoxide groups reporting in the product as glycol groups (as a consequence of hydrolysis reactions) is calculable from the following relationship (assuming the only conversion products are glycol, monoester or diester groups): MA %e,,=l00- (%m+2(%d)) (1) eOep wherein ep=equiv. epoxide present in product as such (usually zero) eO=equiv. of epoxide charged to reaction e9=equiv. epoxide converted to glycol groups MA=moles H3PO4 charged to reaction %m=mole% charged acid reporting as monoester %d=mole % charged acid reporting as diester.

2. Titration of Oxirane Groups The standard method of analysis, using a 25% solution of tetramethylammoniumbromide in glacial HOAc and back-titrating against crystal violet with 0.1N solution of perchloric acid in glacial AcOH, was found to be suitable and was employed in all determinations of oxirane contents given in the following examples.

3. Viscosity Measurements As an indicator of crosslinking and/or molecular weight changes. the viscosities of some of the reaction mixtures described in the Examples herein were measured by the well known Gardner method.

EXAMPLES Example 1 "Solubilization" of DER8-667 by reacting with 65% or 75% H3PO4 and neutralizing with triethylamine. EEW=~2000; 3 H+/oxirane.

A. The resin is dissolved in an equal weight of dioxane and the solution mixed at room temperature with 75% H3PO4 in an acid/resin weight ratio (13.26/200 g) such as to provide 3.0 equivalents of H+ per equivalent of oxirane. A sample of the resulting mixture (number 0) is immediately "quenched" (stored at low temperature) as an analytical control sample. Other portions of the mixture are put in each of seven sequentially numbered vials which are then placed in a 70 oven. The vials are removed from the oven in number sequence at the elapsed times given in the following table and rapidly cooled to "quench" reaction on-going therein.

Samples of the contents are then titrated for oxirane (EEW), free H3PO4, phosphomonoester and phosphodiester. The Gardner viscosity of each reaction mixture is determined and its dispersibility in water, after neutralization with triethylamine, is checked.

B. Experiment A is repeated, but using an amount (15.3 grams) of the 65% acid such as to provide 3 acidic hydroxyls (3 equivalents of H+) per equivalent of the resin.

The results of Experiments A and B are summarized in Table 1 following.

TABLE 1 A*-1 A-2 A-3 A-4 A-5 A-6 A-7 B**-1 B-2 B-3 B-4 B-5 B-7 Reaction 1/2 1 1-1/2 3 4 5 6 1/2 1 1-1/2 3 4 6 Time &commat; 70 C, Hrs %Oxirane 27.4 45.6 75.3 86.5 94.0 95.8 98.1 62.8 75.8 87.9 93.9 94.1 95.4 Consumed Viscosity, 77 144 259 331 293 173 160 79 133 164 135 118 106 Gardner, sec H2O disp.*** No Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Free acid% - 51.7 47.9 42.8 47.5 55.2 51.0 54.0 54.9 49.7 53.2 53.1 53.0 Monoester% - 41.2 45.6 50.1 47.9 41.0 46.8 41.7 40.5 45.5 42.9 44.9 44.6 Diester% - 0.71 6.7 7.1 4.6 3.9 2.2 4.3 4.6 4.9 4.0 2.0 2.4 %Oxirane consumed which reports as glycol groups - 8.2 21.5 25.6 39.1 49.1 47.9 19.9 34.4 37.0 45.8 48.0 48.2 Notes: * 75% H3PO4 ** 65% H3PO4 *** dispersible.

Example 2 Solubilization of DERR-664 by reacting with 85% or 99% H3PO4, in dioxane at reflux, and neutralizing with triethylamine. EEW 1000; H+/oxirane ratio=3: 1.

A. 25 grams (0.025 equiv.) of DERR-664 was dissolved in 25 grams of dioxane.

To the resulting solution was added 25 grams (-0.076 equiv.) of a 10% solution of 100% H3PO4 (99%, allowing for some moisture uptake in handling) in dioxane. The mixture (solution) was heated to reflux (~101 ), refluxed 3 hours and cooled to room temperature. The acid number of the reaction mixture was found to be 124.05 (vs 102, theoretical for adduction of one oxirane group per molecule of H3PO4). No unreacted epoxide could be detected.

The reaction mixture was extracted with 50 ml of water and the acid content of the extract was found (by titration with dilute KOH) to be 0.013 equivalents. The "raffinate" required 3 grams (0.03 equivalents) of triethylamine for neutralization.

The total acid consumption for the reaction was then 0.076-(0.013+0.030)=0.033 equivalent, or 0.033/0.025=1.32 equivalent of H+ per oxirane.

B. Experiment A was repeated, except that 25 ml of a dioxane solution containing 2.94 grams (0.076 equivalent) of 85% H3PO4 were used in place of the acid solution employed in A. The acid number of the reaction mixture was lower (108), the acid contents of the extract and raffinate respectively were 0.009 and 0.035 and the acid consumed in the reaction, again, was 0.033 equivalent.

Both of raffinates A and B (after being stripped of residual dioxane), gave faintly hazy but stable dispersions in water at a solids level of 41%.

Example 3 Effect of EEW and H+/oxirane ratio on solubilization of DGEBA-type epoxy resins by reaction with 85% H3PO4.

Four DGEBA-type resins varying in EEW from 190 to 2000 were separately reacted at 750 in dioxane with amounts of 85% H3PO4 such as to provide from 0.5 to 3.0 equivalents of H+ per oxirane. The dispersibility of each reaction mixture, as such and when neutralized with triethylamine and stripped of solvent, was checked.

The results are summarized in Table 2 following. From the data in the table it appears that H+ to oxirane ratios as low as 0.5 are generally inoperable for the purposes of the present invention.

The data also suggests that ratios above about 1.0 are essential to dispersibility only for resins having EEW's above about 1000.

TABLE 2 Resin DERR-331 DERR-661 DERR-664 DERR-667 EEW 190 500 1000 2000 Eq. Acid/Epoxide* .5 1.0 1.5 3.0 .5 1.0 1.5 3.0 .5 1.0 1.5 3.0 .5 1.0 1.5 3.0 % Acid (85%) 9.3 17.0 23.5 38.1 4.15 7.97 11.5 20.9 1.91 3.75 5.5 10.4 .96 1.9 2.84 5.5 Time &commat; 75 C 1 hour 3 hours 3 hours 7 hours

(V Very viscous) (G Gelled) Dispersibility (+ Dispersible) in H2O # (- Not dispersible) (? Borderline) a) Resin+Dioxane G + + + G - - - V - - - V - - b) Resin+Dioxane G + + + G + + + V + + + V - ? + +Amine c) Resin+Amine G + + + G + + + V + + + V ? ? + +water,less dioxane *P-OH/oxirane ratio.

Example 4 Solubilization of DER8-667 by reaction with a condensed phosphoric acid source material. (8 P-OH per oxirane.) A solution of 100 grams (0.05 equiv.) of DER(B)-667 in 200 grams of dioxane was dripped slowly into a stirring solution of 17.8 grams (0.1 moles) of pyrophosphoric acid (equivalent to 0.2 moles of H3PO4) in an equal weight of dioxane, the temperature of the reaction mixture being maintained at 80--1000C.

In about 0.5 hour, a soft gel had formed. Upon addition of another 270 grams of dioxane, the gel only partially dissolved, but the resulting mixture was stirrable.

After another 3 hours reaction time, no unreacted epoxide could be detected (in the continuous, liquid phase). Titration of a sample of the gel phase (dissolved in a mixed solvent; 17% H2O, 17% methanol and 66% methyl ethyl ketone) showed it to consist largely of DER8-667 in which the oxirane groups had been converted to phosphodiester groups.

The reaction mixture was converted to a homogeneous liquid by adding 10 grams (0.56 mole) of water and stirring and heating for 3 hours. Titration of the final solution showed that all diester groups and P-O-P links had been hydrolyzed.

Since a good determination of the amount of free phosphoric acid could not be made by titration, an aliquot of the reaction mixture was repeatedly extracted with water and the combined extracts were titrated. The proportion of the oxirane groups (in the 667) converted to phosphomonoester groups was calculated to be 71.4% (from the difference between the amount of H3PO4 charged (as H4P2O,) and the final free acid content in the aqueous extracts). The proportion of oxirane groups converted to glycol groups was then (by difference) 28.6% and the number ratio of glycol to monoester groups in the final product was 0.4.

Although the continuous liquid phase co-formed with the gel was not separately worked up, it was estimated from the titration curve for this phase that only about 10% or less of the 667-derived product it contained was diester, the rest being monoester.

Dispersions were prepared from final reaction mixture samples which had and had not been esesntially freed of H3PO4 (by extraction with water). The samples were neutralized to a pH of 7.5-8.0 with triethylamine, stripped and diluted with water to a non-volatiles level of 16 wt%. The unextracted sample gave a viscous, hazy white dispersion which had good film forming properties. The extracted sample gave a water-thin, clear blue dispersion, but the film forming properties of the latter dispersion were poor.

Example 5 Utility of neutralized reaction products of DER8-667 with H3PO4, as dispersants for a DGEBA epoxide having EEW's up to --13,000.

A. A "high" ester content DERd9-667/H3PO4 product was prepared by reacting DER8-667 (EEW N1550), with 1 mole (6 phr) of H3PO4 (as 99% aq. H3PO4) per equiv. of epoxide, in methyl ethyl ketone at 800C for !5 hours. No unconverted epoxide remained and the glycol to ester ratio was 34/66=1/1.94. This product was mixed with successively lower amounts of DER8-684 solution (40 wt% solids in MEK) and each of the resulting mixtures was neutralized with two equivalents of triethylamine, diluted with 25 phr of methylene chloride and mixed with 100 parts - of water per 100 parts of total resins. The stripped products (emulsion) contained 50 wt% total solids and were evaluated as dispersions. The results are given in Table 3.

TABLE 3 Dispersibility in Water of Neutralized Mixtures of DER-684 and DERO-667/6 phr H3PO4 Reaction Product phr phr DERV684 PO4 Dispersion Quality 60 2.0 Dispersion grainy, settled on standing.

50 2.6 Borderline acceptability, slight settling noted.

40 3.1 Borderline acceptability, slight settling noted.

20 4.1 Good dispersion.

No settling.

B. 680 grams of a 40 wt% solution of DER-684 in MEK was heated at 780C for 24 hours with 3.72 grams of pyrophosphoric acid and the amount (0.38 gram) of water required to convert it to 100% H3PO4 (-1.5 phr). The EEW of the resin never rose above 50,000 (~74% oxirane conversion) and the neutralized final product did not give a dispersion with water. When the 50,000 EEW product resin was substituted for DER(B)-684 in the mixtures of part A above, somewhat poorer dispersibility was observed.

The dispersed mixtures obtained in the experiment of part A, at DER-684 contents of 50 phr and less, exemplify a unique and superior embodiment of the present composition invention. Those skilled in the art will appreciate the advantages, in terms of cured coating properties, conferred by the presence of a DGEBA resin component having an (average) molecular weight of about 26,000.

Further, it is apparent from the quite slow oxirane conversion rate observed in the experiment of part B that most or all of the DER-684 oxirane groups are present as such in the -684 dispersions, as formed. The latter groups would not be expected to remain unconverted for an indefinite period of time in the presence of both water- and acid-hydrolyzing amine phosphate groups (even though the DER8-684 is dispersed, rather than dissolved). However, aqueous dispersions of neutralized DER(F684 (as such or reacted with H3PO4) and DER(E-667/H3PO4 reaction product mixtures appear to be properly regardable as highly novel, oxiranecomprising compositions of matter.

Example 6 Reduction of free acid content. In reaction product of high EEW DGEBA Resin with 6 phr H3PO4, to improve dispersibility.

A solution of 95 grams (0.0198 equiv) of DER(B)-669 (EEW 4800) and 5.88 grams 85% H3PO4 (0.051 moles H3PO4; 7.73 P-OH per oxirane) in MEK was refluxed at 80"C for 15 hours. The reaction mixture was cooled and sampled for analysis: Unreacted oxirane content, none; Oxirane converted to phosphomonoester, 40%; Oxirane converted to glycol, 60%; GlycoVester group ratio, 3/2; Free H3PO4 in product, 4.31 grams or 4.27 wt% of non-volatiles present.

The reaction mixture was divided into portions. One portion was neutralized with triethylamine to a pH of 7, diluted with water and stripped. The stripped material was not a stable dispersion.

A second portion was mixed with enough water (an equal volume of water) to precipitate the polymer. The liquid phase was decanted and the precipitate triturated with more water, which was then also decanted. The polymer was taken up in MEK and the solution sampled for analysis. 30% of the free acid was found to have been removed by washing; the H3PO4 present constituted approximately 3 wt% of the resinous product. A stable, opaque, non-grainy dispersion (50% solids) was obtained by neutralizing this product to pH 7 with triethylamine, diluting it with water and stripping off the MEK.

Example 7 Effect on substrate wetting of substituent on phenol used to cap DGEBA resin.

DERO-664 was separately reacted with 0.5 molecular proportion each of phenol, p - t - butylphenol and p - nonylphenol per equivalent of oxirane. One gram mole of the phenol reactant, 0.3 gram of A-l catalyst (ethyl triphenol phosphonium acetate) and 15 milliliters of xylene were added to 250 grams (0.13 g moles) of molten (-120"C) DER8-664 and the mixture heated, with stirring, to 2000C and refluxed until the EEW was approximately equal to the sum of the molecular weight of the phenol and twice the initial EEW of the resin. The xylene was stripped off, a retain sample taken and an equal weight of MEK stirred into the residual, capped resin.

The resulting solution was heated to reflux and 0.5 mole of H3PO4 (as the 85% aq. acid) was diluted with an equal weight of MEK and added dropwise. Refluxing was continued until the EEW was about 60,000 or remained constant. The solution was cooled, neutralized with 1 mole of triethylamine and diluted with the solids therein. The diluted mixture was stripped with stirring under reduced pressure at 70"C until no more MEK came off. The stripped product was a stable aqueous dispersion containing (by analysis) approximately 50 wt% solids. Portions of the dispersion were diluted to 30, 35 and 40 wt% solids with water.

Brookfield RVT viscosities were determined for each of the four dispersions (12, total), using a &num;4 spindle at 100 rpm. Surface tensions were measured (average of 5 replicates each) with a Fisher (Registered Trade Mark) Surface Tensiomat using a 5.990 cm diam. wire circle.

The wetting abilities of the different dispersions on three types of substrates were judged by putting a small amount of each of the dispersions to be compared on the same panel, drawing them simultaneously in parallel with a &num;18 wire wound rod and observing the resultant film strips for continuity, "crawling", spreading or shrinking, "beading", "fish eyes" and evenness. Overall ratings of from 1 (best) to 3 (poorest) were assigned, on the basis of the foregoing visual criteria, within each set. pH's were checked for all of the dispersions and found to be consistently within the range of 8.45--8.55.

The results of the viscosity, surface tension and wetting evaluations are given in Table 4.

TABLE 4 Surf. Tension Relative Wetting % Solids Viscosity cps Dynes/cm Ability of Resin Capped with Substrate in Disp. NP(1) BP(2) P(3) NP BP P NP BP P Aluminium 30 13 12 11 46 50.8 46 1 3 3 (CH2Cl2-cleaned) (est) 50% area beads beads covered 35 20 20 20 46.5 50 54 1 2 3 wets slight severe crawl crawl 40 39 30 30 50.8 50 53.3 1 2 3 wets moderate severe crawl crawl Tin-free steel 40 39 30 30 50.8 50 53.3 1 2 3 (cleaned) crawl puddles large Cold-rolled steel 30 13 12 11 46 50.8 53.3 1 2 3 (not cleaned) slight moderate more crawl crawl crawl Notes: (1) Nonyl phenyl (2) t-butyl phenol (3) Phenol.

It is apparent from Table 4 that the wetting ability goes down as R20 (in formula (q)) goes from nonyl to t - butyl to H, the differences being most pronounced (at 35 or 40% solids) on a clean aluminum substrate and least pronounced (at 30% solids) on uncleaned cold-rolled steel. These effects roughly correlate with the somewhat higher viscosities and lower surface tensions of the nonylphenol-derived dispersion.

Example 8 Sequential co-reaction of H3PO4 with DER(!)-667 and a phenylglycidyl ether substituted with methylol groups (Type (b) E2 epoxide) (EEW=720; 0.935 P OH/oxirane).

70 Ibs (-0.02 lb moles) of DER)-667 was dissolved in 100 lbs of methylene chloride and 20 Ibs of IPA, warmed to reflux in 2 hours, and reacted 24 hours at 410 with 5.0 Ibs of 85% H3PO4. The oxirane content, on a solids basis, was less than 0.1%. 30 Ibs (-0.1 Ib moles) of the glycidyl ether of 1,6 - bis(methylol) - 4 - t butylphenol was then reacted in at 410C for 33 hours. The oxirane content again was less than 0.1%; acid number 14.5. 175 Ibs of distilled water, and then 80 Ibs of triethylamine, were stirred in. After the solvents were stripped off, the residual dispersion had a pH of 8.5 and displayed excellent stability and solution characteristics, i.e., no settling, low opacity and no grain. Coatings were applied on aluminum test strips at a non-volatiles level of 20 wt%, in water, using a &num;10 wirewound rod and with no pretreatment of the test strip surfaces. Good wetting, excellent flow and full cure in 8 minutes at 3800F. (1930C.) or 5 minutes at 4000 F.

(204"C.) or 3 minutes at 4400 F. (2270C.) were obtained. The chemical resistance of the films was excellent; usually, 50 acetone double rub were passed. Excellent wetting was also observed on tin-free steel coupons. No blushing of coatings on either type of surface was observed after 30 minutes immersion in boiling water.

The preceding cure times were cut in half when 1% p-toluenesulfonic acid (solids basis) was included in the water-thinned dispersion, with no loss of film properties.

Examples 9-12 Effects on viscosity, cure rates and film properties of neutralizing sequential co-reaction product with different amines.

A master batch of acid/E1/E2 Droduct was made up in a two-step esterification essentially as in Example 2. (EEW of E1+E2=720; 1.32 P-OH/oxirane.) In the first step, 7ao grams (0.2 g moles) of DER8-667, in 1000 gra (204"C), instead of 3 minutes); acetone resistance somewhat inferior; almost no tendency to dry out before cure; much higher viscosity and 1% p - toluenesulfonic acid was less effective in accelerating curing.

* Example 12 To 1000 grams of dispersion, 35.5 grams of diethylaminoethanol was added. A highly viscous but readily stripped gel resulted. After stipping, the residual dispersion was still quite viscous and was therefore diluted to 15% solids (rather than 20%) with water. The differences observed between coatings prepared from the resultant solution and the coatings of Example 9 were as follows: much higher solution viscosity; no tendency to dry out before curing; slower curing (7 minutes at 400"F (204"C) instead of 5 minutes) and no improvement in effect of p toluenesulfonic acid (1%) on cure rate.

Comparison of Examples 2 and 4 show that trimethyl and triethyl amines were generally equivalent for neutralization of the co-reaction product. Similarly, no substantial difference is seen (Examples 11 and 12 between N,N dimethylethanolamine and the N,N - diethyl homolog thereof. Comparison of Example 8 (or 9) and 10 shows that a 1:1 mixture of triethylamine and N,N dimethylethanolamine gives a faster uncatalyzed cure rate, a higher dispersion viscosity and a reduced tendency for the uncured film to dry out. However, it is apparent from Examples 11 and 12 that the use of either of N,N - dimethyl- and N,N - diethyl ethanolamine gives generally poorer results, except for a further decrease in dry-out tendency.

Example 13 Inverse sequential reaction in ethanol of a nonyl substituted monofunctional type (b) E2 epoxide and a bisphenol - F resin (El) with H3PO4. (EEW=284); 1.15 P-OH/oxirane- electro-coatable product.

11.25 grams (0.096 g mole) of 84% aq. H3PO4 was added to a mixture of 5 grams of ethanol-B with 38.75 grams (0.0965 g mole) of the glycidyl ether of 2,6 dimethylol - 4 - nonylphenol at room temperature. A slight exotherm resulted. A mixture of 5 grams of ethanol - B and 31.8 grams (0.0965 g moles) of an experimental resin (nominally, the diglycidyl ether of bisphenol-F) was then added.

This resulted in an exotherm which raised the temperature of the final mixture to about 100"C. The reaction mixture was allowed to cool to and stand at room temperature over a weekend.

67 grams of the product (89% non-volatiles) were stirred with 33 grams of water and the resulting dispersion neutralized (to pH 6.0) with 5.6 grams of diethylamine. Addition of 10 grams more of ethanol and 18.4 grams more of water gave a dispersion containing 50 wt% of non-volatiles.

The dispersion was used to deposit a film on tin-free steel by electrocoating.

Two steel coupons, each 1-1/2"x4" and spaced 2" apart, were immersed to a depth of about 3 in the dispersion and 100 volts D.C. applied between the coupons (electrodes). The current drawn dropped rapidly (30 seconds) from an initial value of 150 milliamps to a value of 50 mm. The anode (negative) electrode was found to be covered with a coherent coating of the resin. After being baked 15 minutes at 175"C, the resulting film showed good resistance to boiling water.

A film of the dispersion was drawn on a tin-free steel coupon (not treated to remove oils) and showed excellent wetting. After being baked 10 minutes at 185"C, the film was resistant to acetone, showed excellent resistance to boiling water and did not crack when the coupon was bent in a 1" radius curve.

When a portion of the dispersion was thinned with water to a non-volatiles content of 5 wt%, the thinned dispersion approximated a true solution in appearance and action. Films of the thinned dispersion electrodeposited excellently on aluminum and cold rolled steel and, after being baked 10 minutes at 1750C, showed excellent acetone resistance and withstood 50 inch pounds in the reverse impact test.

Example 14 and Comparative Run A Simultaneous co-reaction of DER(b667 (E') and a type (m) E2 epoxide with phosphoric acid. (EEW=465 0.85 p-OH/oxirane.) 420 grams (0.26 g moles) DERt667 was dissolved in 900 grams of methylene chloride and 180 grams of isopropanol. 180 grams (0.286 g moles; 1 equiv.) of heatfluidized (-8-100"C) DEN0D (Dow Epoxy Novolak)438 was stirred in, and then 42 grams of 85% H3PO4. The mixture was held at room temperature for an hour and then heated to reflux (41 ) and reacted at relux for 16 hours. At this point the EEW (solids basis) was 49,000 (% oxirane-43x100/4900=0.09+%) and the acid number was 53. 800 grams of distilled water was stirred in and the resulting dispersion divided into two equal portions. One portion, comparative Run A, was neutralized with 50 grams of 25% aq. NaOH and the other portion, Example 14 with 30.5 grams of triethylamine. The caustic-neutralized portion was difficult to strip to a solids content higher than 15 wt% but both stripped products were readily thinnable with water to give stable, homogeneous, grain-free dispersions. DENB 438 has an EEW of about 180, an epoxide functionality of about 3.5 and is a polyglycidyl ether of phenol-formaldehyde novolak.

Product Compositions Versus Water-thinnability Gel Permeation Chromatographic analysis has shown that only very minor amounts, if any, of oxirane are consumed by reactions other than with water or P OH groups and essentially no triester groups are formed. Also, only minor amounts, if any, of polyfunctional diesters (esters in which an epoxide molecule is linked through phosphodiester groups to more than one other epoxide molecule) are produced in the reaction unless the reaction medium comprises about 75 wt% or more of a solvent like dichloromethane.

It is evident from the data given in the foregoing examples that glycol group formation results not only from oxirane hydrolysis; hydrolysis of ester (phosphodiester) groups also proceeds to a limited extent, although more significantly at higher reaction temperatures and when more dilute H3PO4 is used.

Also, direct esterification of alcoholic hydroxyl groups present as such in E1 (or formed upon P-OH/oxirane adduction) has a small effect on the total content of phosphomonoester groups in the final product (after, say, 3-6 hours reaction time).

It is particularly surprising that solubilization (water-thinnability) of resins such as DER(b667 can be achieved by a reaction in which up to about 95% of the oxirane groups are converted to glycol groups, rather than to acidic, salt-forming groups. DGEBA resins are already polyfunctional in alcoholic hydroxyl groups, but are nevertheless distinctly hydrophobic. Conversion of, on an average, one oxirane per molecule to a glycol group would not be expected to noticeably decrease the overall hydrophobicity of the molecule Furthermore, conversion of the remaining oxirane groups (somewhat less than one per molecule, on the average) to alpha-hydroxy phosphomonoester groups would not appear to provide enough salt (neutralized) groups to result in solubilization. Yet, the facts are that the oxirane groups in the resins are converted almost entirely to glycol and (mono)ester groups and that even at an average content of substantially less than one monoester group per molecule, the neutralized products derived from E1 resins having EEW's up to about 3200 are water-thinnable. It is even more suprising that DGEBA resins having EEW's as high as 5500 can be made water-dispersible by the present process.

The product will retain its essential character even if it additionally contains an amount of phosphodiester groups (each deriveable from reaction of a molecule of phosphoric acid with an oxirane group in each of two different epoxide molecules) in an amount such as to account for up to about 10 percent of the phosphorous present therein. At some stages of the process of the present invention, higher proportions of diester groups may be present, but such groups tend to hydrolyze to monoester and glycol groups. Even at room temperature, this hydrolysis reaction will generally continue (so long as any water is present) until little if any diester groups remain. Since neutralization is usually carried out in the presence of water, the content of diester groups thereafter will ordinarily be very low anyway.

When an acid/epoxide reacton product containing a relatively large amount of free phosphoric acid is neutralized, particularly with an inorganic base, the amount of free acid-derived salt present in the neutralized product may be such that the dispersibility of the salified resin in what, in effect, is a brine, rather than in water, becomes a consideration. However, there are obvious expedients for avoiding this Problem and in any case the amount of base in the neutralized product will be at least the sum of that consumed by the free acid, and whatever amount is required to salify enough ester P-OH moieties to render the resin molecules dispersible in water.

It is apparent, from Example 5 herein, that the utility of the present invention may be indirectly extended to DGEBA type epoxides having EEW's as high as 13,000! That is, resins of the latter type, such as DER-684, which do not yield water-thinnable products when reacted with phosphoric acid and neutralized, may nevertheless be co-dispersed (as such or as esterified resins) with (neutralized) reaction products of the present invention, in water.

On the basis of some experiments not detailed herein, it has been found that the products derived from DGEBA resins having EEW's an order of magnitude lower than DERt667 are not effective dispersants for DER-684. However, essentially all of the neutralized products of the invention are apparently capable of dispersing substantial proportions of unconverted DGEBA molecules of at least as high an EEW as those the neutralized products are derived from. Neutralized products of the invention in which up to about 54% of the charged oxirane groups remain unconverted can be dispersed in water and give useful coatings. Assuming a statistical distribution of the unconverted oxirane groups in the resin molecules, it is apparent that substantial proportions of molecules having all of their original oxiranes intact are present in such products.

Thus, compositions of the present invention as defined earlier herein (see summary of the invention) additionally may comprise molecules of formula (a) in which both oxiranes are intact or one of them is intact and the other is replaced by a glycol or betahydroxy phosphomonoester group, the average molecular weight of said molecules being not more than about 10 times the average molecular weight of those molecules of formula (a) in which both oxiranes have been replaced by glycol or betahydroxyester groups. (The ratio of EEW's for DER-684 and DER(e-667 is 13,000/1550 or 8.4.) The proportion of such oxirane-containing molecules present may be as much as to provide about one oxirane per glycol or ester group in the cmposition. That is, the number of oxirane groups may be as high as the total number of glycol and beta-hydroxy phosphomonoester groups.

The E2-type resins derived from epoxides of formulas (b) and (p) are highly advantageous for the practice of the present invention. Such epoxides in which R8 is alkyl of from 3 to 10 carbons are particularly preferred for the preparation of E2derived resins. Among the latter, those compounds in which p is I and R8 is t butyl or normal nonyl are most preferred as conferring superior ability on the mixed E' and E2-derived resin dispersions to wet hydrophobic substrates, such as aluminum stock which is not oil-free.

The diglycidyl ether of 2,6,2',6' - tetra(methoxymethyl)bisphenol-A is a preferred alkoxy methyl substituted epoxide (formula (1) for preparation of E2derived resins (dispersions)).

The relative proportions of the E'- and E2-derived resins (salified) in the composition of the invention can vary widely, depending on the characteristics desired in the end product (cured coating, sealer, surface active material, primer or whatever). In most applications, an end product whose properties are essentially those of the E'-derived resin will be desired and the mole ratio of E1- to E2epoxide derived species may have a value of up to about 100. However, in other applications the El epoxide may act more as a modifier than as the main epoxide component and the mole ratio of E'-derived to E2-derived species in the end product may have a value down to about 0.1. In those instances where the E2epoxide (or a low molecular weight E'-epoxide) undergoes some oligomerization during reaction with the acid, each monomer unit in the oligomer is counted as an individual molecule in assessing the E'/E2 ratio.

The content of free (unesterified) phosphoric acid in the mixed products can vary from none up to about 85 parts by weight per hundred parts of epoxidederiveable molecules. However, unless the contemplated end use of the salified, mixed product requires enhanced fire retardancy or the ability to release a substantial amount of dissociable base (to a strongly acid environment or upon heating), "free" acid contents of more than about 5 weight percent will generally be undesirable and contents of about 1 part by weight or less of H3PO4 per hundred parts of epoxide-deriveable (or derived) molecules will be preferable.

According to a further aspect the invention provides a water-thinnable, resinous phosphate composition consisting essentially of: (A) resin molecules containing 1,2 - glycol- or beta-hydroxy phosphomonoester groups which are derived from the conversion of the oxirane group in an epoxide represented by one of formulae (a) to (n)

wherein Q, independently, in each occurrence, is

n is an integer of from 0 to 40, r is zero, 1 or 2 and, independently in each occurrence; R' is H, methyl or ethyl; R2 is -Br, -Cl or a C, to C4 alkyl or alkenyl group; R3 is a C1-C4 alkylene or alkenylene group, C(CF3)2 -CO-, -SO2-, -S-, -O- or a valence bond; and R4 is -Br, -Cl or a C1 to C4 alkyl or alkenyl group; (b) a methylol- or alkoxymethyl-substituted phenylglycidyl ether of the following formula

wherein Y is H or a C, to C4 alkyl or alkenyl group, each YO-CH2- group is either ortho or para to a glycidyloxy group, x is 1, 2 or 3, p is O or 1 and a is 1 or 2, R1, independently in each occurrence, is H, methyl or ethyl, R5 is a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, alkylphenyl, phenylkyl, phenoxy, -Br, -Cl group or a

group, wherein y is 0, 1 or 2, Y and R1 are as above defined, T is a C1-C4 alkylene or alkenylene group, C(CF3)2 -SO2, -S-, -O- or a valence bond, R6 is -Br, -Cl or a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, alkylphenyl, phenalkyl or phenoxy group, and t is 0 or 1; with the proviso that (x+a) cannot exceed 4 and (x+y) is from 2 to 4; (c) a methylol- or alkoxymethyl-substituted, (2,3 - epoxy)propylbenzene of the formula

wherein: b is 1 to 3, d is 0 or 1, R7 is C1-C12 alkyl or

Y' is H or a C, to C4 alkyl or alkenyl group, R' is H, methyl or ethyl, with the proviso that (b+d) cannot exceed 3; (d) di- and trioxides of unsaturated C4 to C28 hydrocarbons containing two or three non-aromatic, carbon-to-carbon double bonds and, optionally, a -Br, -Cl or -F or hydroxy substituent which is not attached to a carbon of any of said double bonds; (e) epoxy ethers of the formula R8-O-R9, wherein each of R8 and R9 is the same or a different monovalent radical deriveable by abstraction of hydrogen from a C3-C12 aliphatic-, alicyclic- or phenalkylene-oxide; (f) 2,3 - epoxypropyl halides or alcohols of the formula

wherein A is -Cl, -Br or -OH and R is -H, -CH3 or -C2H5; (g) glycolmonoethers of the formula

and glycol diethers of the formula

wherein R is -H, -CH3, or -C2H5, R10 is -H or -CH3, X is -H, -CH3 or -C2H5, g is 1, 2 or 3 and h is 2 or 3; (h) diglycidyl ethers of the formula

wherein R11 is a divalent aliphatic or cycloaliphatic hydrocarbon radical of from 2 to 22 carbons and R is -H, -CH3 or-C2H5, (i) mono or diglycidyl ethers of

(i) mono-, di- or triglycidyl ethers of glycerine; (k) trifunctional aromatic epoxides

O wherein Z is H2C-C-CH2-O-, R R12 is C1-C2 alkoxy, C1-C6 alkyl or C2-C6 alkenyl R13 is H, C1-C12 alkyl or C2 C12 alkenyl, R14 is a -C8 alkyl, alkenyl, cycloalkyl, cycloalkenyl or aralkyl group, ortho or para to those Z-CH2- moieties on the benzene ring to which said group is attached, R is as previously defined and R15 is a C1-C4 alkylene or alkenylene group or -SO2-; (l) tetraglycidyl ethers of the formula

wherein R16 is a C1 to C6, divalent aliphatic hydrocarbon radical,

-SO2-, -S-, -O- or a valence bond and Z is

(m) tri- to pentafunctional epoxy novolaks of the formula

wherein p is 1 to 3, R17 is H or -CH3, independently in each occurrence, R18 is an alkylene group of 1 to 4 carbons and

(n) methylol or alkoxymethyl substituted, oligomeric monoepoxides of the formula

wherein u is 0, 1,2 or 3, R', independently in each occurrence, is H, methyl or ethyl and R'9, independently in each occurrence, is a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, phenalkyl or alkylphenyl group, the number ratio of glycol to monoester groups in said molecules being from 0 to 1.3, the proportion of said molecules so derived from epoxide molecules of formula (a) being from 10 to 100 mole percent and the average EEW of the epoxide molecules from which said resin molecules are derived being from 200 to 3200, (B) from 0 to 25 parts by weight of ortho phosphoric acid per 100 parts of said resin molecules, and (C) a base which is ammonia or an organic amine in such amount that at least enough of the P-OH moieties in said resin molecules are salified thereby to render said molecules dispersible in water.

In one preferred embodiment, the proportion of said resin molecules derived from epoxide molecules of formula (a) is 100 mole percent.

In another preferred embodiment, the proportion of said resin molecules derived from epoxide molecules of formula (a) is from 12 to 50 mole percent and the proportion derived from epoxide molecules of formulae (b) to (n) is from 88 to 50 mole percent. Preferably, the resin molecules derived from epoxides of formulae (b) to (n) are derived only from epoxides of formulae (b), (c) or (n), or from mixtures thereof.

According to yet further aspect the invention provides a process for making water-thinnable salts of resinous, acidic phosphate esters which are convertible to hydrophobic, high performance, thermoset resins, said process comprising: (I) reacting orthophosphoric acid with (1) a polyether epoxide resin E' consisting essentially of molecules of formula (a) and, necessarily, if the EEW of E1 is greater than about 3200 or, optionally, if the EEW of E' is less than about 3200, with (2) an epoxide E2 which consists essentially of molecules, each of which, independently, either is a kind represented by formula (a) but has a different value of n than E' or is one of kinds (b) to (n) said reaction being carried out by contacting E', and any E2 epoxide which is employed, with orthophosphoric acid mixed with 0 to 4 molecular proportions of water per molecular proportion of H3PO4, until essentially all of the oxirane groups originally present remain unreacted, the amount of said acid employed being such as to provide at least 0.7 acidic hydroxyl groups per oxirane group, and the relative amounts of E' and E2 employed being such that the average EEW for E' and E2 combined is from 200 to 3200, and (II) contacting the resulting reaction product with at least enough of a base which is ammonia or an organic amine to render it dispersible in water.

Preferably E' is an epoxide in which Q, in all occurrences, is

i.e. E' is preferably an epoxide of the formula

Particularly preferred are E' epoxides of the foregoing formula in which Q, in essentially all occurrences, is either

In a preferred embodiment of the process E2 is present and consists essentially of molecules of the formula

and R5 is an alkyl group of 4 to 9 carbon atoms.

In another preferred embodiment of the process E' has an EEW greater than 3200 and E2 is an epoxide of the formula (a) having an n value of 3 or less.

In a further preferred embodiment of the process the phosphoric acid is charged to the reaction as aqueous orthophosphoric acid, of a concentration of from 70 to 90%, and in an amount such as to provide from 0.8 to 3 acid hydroxyls per oxirane group.

Other preferred reagents and reaction conditions for the process are as previously described.

Claims (79)

WHAT WE CLAIM IS:

1. A water-thinnable, resinous phosphate composition comprising: (A) resin molecules containing 1,2 - glycol- or beta-hydroxy phosphomoester groups which are derived from the conversion of the oxirane groups in a polyether epoxide resin E' having the formula

wherein Q, independently, in each occurrence, is

n is an integer of from 0 to 40, r is zero, 1 or 2, and, independently in each occurrence; R' is H, methyl or ethyl, R2 is -Br, -Cl or a C, to C4 alkyl or alkenyl group, R3 is a C1-C4 alkylene or alkenylene group, C(CF3)2 -CO-, SO2, -S-, -0-, or a valence bond, R4 is -Br, -Cl or a C, to C4 alkyl or alkenyl group; and R20 is H or alkyl of 1 to 12 carbons, the average epoxide equivalent weight (EEW) of the epoxide molecules from which the resin molecules are derivable being from 172 two 5500 (B) from 0 to 85 parts by weight of ortho phosphoric acid (H3PO4) per 100 parts by weight of the resin molecules, (C) a base which is ammonia or an organic amine in such amount that at least enough of the P-OH moieties in the resin molecules are salified thereby to render the molecules dispersible in water.

2. A composition as claimed in Claim I additionally comprising other molecules, containing 1,2 - glycol- or beta-hydroxy phosphomonoester groups which are derived from the conversion of the oxirane groups in E2, a vicinal epoxide other than one of formulae (a) or (q), having an EEW of from 90 to 2000, and the mole ratio of the E' molecules to E2 molecules being from 0.1 to 100.

3. A composition as claimed in Claim I or Claim 2 wherein the number ratio of glycol to phosphomonoester groups is not higher than 18.

4. A composition as claimed in any one of the preceding claims in which Q, in each occurrence, is

5. A composition as claimed in any one of the preceding claims in which Q, in essentially each occurrence, is either

6. A composition as claimed in any one of the preceding claims in which Q, in essentially each occurrence, is

7. A composition as claimed in any one of the preceding claims in which n is from 10 to 13.

8. A composition as claimed in any one of the preceding claims in which E' is of formula (a) in which Q, independently, in each occurrence, is

in which n is an integer of from 0 to 40, r is 0 or 2 and, independently in each occurrence; R1 is H, R2 is Br or Cl, and R3 is (CH3)2C

9. A composition as claimed in any one of Claims 2 to 8 wherein E2 is one or more of: (b) a methylol- or alkoxymethyl-substituted phenylglycidyl ether of the following formula

wherein Y is H or a C, to C4 alkyl or alkenyl group, each YO-CH2- group is either ortho or para to a glycidyloxy group, x is 1, 2 or 3, p is 0 or 1 and a is 1 or 2, R', independently in each occurrence, is H, methyl or ethyl, R5 is a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, alkylphenyl, phenalkyl, phenoxy, -Br, -Cl group or a

group, wherein y is 0, 1 or 2, Y and R are as above defined, T is a C1-C4 alkylene or alkenylene group, C(CF3)2 -SO2-, -S-, -O- or a valence bond, R6 is -Br, -Cl or a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, alkylphenyl, phenalkyl or phenoxy group, and t is 0 or 1; with the proviso that (x+a) cannot exceed 4 and (oxy) is from 2 to 4; (c) a methylol- or alkoxymethyl-substituted, (2,3 - epoxy)propylbenzene of the formula

wherein: b'is I to 3, d is 0 or 1, R7 is C1-C12 alkyl or

Y' is H or a C, to C4 alkyl or alkenyl group, R' is H, methyl or ethyl, with the proviso that (b+d) cannot exceed 3; (d) di- and trioxides of acyclic or cyclic, C4 to C28 hydrocarbons or esters containing two or three nonaromatic, carbon-to-carbon double bonds and, optionally, a -Br, -Cl or -F or hydroxy substituent; (e) epoxy ethers of the formula R8-O-R9, wherein each of R8 and R9 is the same or a different monovalent radical deriveable by abstraction of hydrogen from a C3-C12 aliphatic-, alicyclic- or phenalkylene-oxide; (f) 2,3 - epoxypropyl halides, alcohols or esters of the formula

wherein A is -Cl, -Br, -OH or

R is -H, -CH3, or -C2H5 and R21 is a C1-C15 hydrocarbyl group; (g) glycol monoethers of the formula

and glycol diethers of the formula

wherein R is -H, -CH3 or -C2H5, R10 is -H or -CH3, X is -H, -CH3 or -C2H5, g is 1, 2 or 3 and h is an integer of from 2 to 10; (h) diglycidyl ether or esters of the formula

wherein R11 is a divalent hydrocarbon radical of from 2 to 20 carbons, R is -H, -CH3 or -C2H5 and i and j independently are 0 or 1; (i) mono or diglycidyl ethers of

(j) mono-, di- or triglycidyl ethers of glycerine; (k) trifunctional aromatic epoxides

wherein Z is

R12 is C1-C2 alkoxy, C1-C6 alkyl or C2-C6 alkenyl, R13 is H, C1-C12 alkyl or C2 C12 alkenyl, R14 is a C1-C6 alkyl, alkenyl, cycloalkyl, cycloalkenyl or aralkyl group, ortho or para to those Z-CH2-moieties on the benzene ring to which said group is attached, R' is as previously defined and R'5 is a C1-C4 alkylene or alkenylene group or -SO2-; (1) tetraglycidyl ethers of the formula

wherein R16 is a C1 to Ce, divalent aliphatic hydrocarbon radical,

-SO2-, -S-, -O- or a valence bond and Z is

(m) tri- to pentafunctional epoxy novolaks of the formula

wherein p is 1 to 3, R'7 is H or -CH2, independently in each occurrence, R'8 is an alkylene group of 1 to 4 carbons and Z is

(n) methylol substituted, oligomeric monoepoxides of the formula

wherein u isO, 1, 2 or 3, R', independently in each occurrence, is H, methyl or ethyl and R'g, independently in each occurrence, is a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, phenalkyl or alkylphenyl group; (o) epoxidized triglycerides of unsaturated fatty acids of up to 18 carbons each; and (p) one to one adducts of substituted phenols with diglycidyl ethers of substituted bisphenols, of the formula

wherein R', R2, R3 and r are as defined in preceding formula (a), Y, R8 and p are as above defined in formula (b), v is 1, 2 or 3 and w, independently in each occurrence is 0, 1 or 2.

10. A composition as claimed in Claim 9 wherein E2 is selected from epoxides of types (b), (c), (n) and (p).

11. A composition as claimed in Claim 9 wherein E2 is an epoxide of formula (b) in which Y is H or -CH3, x=2, p=l and R8 is an aliphatic hydrocarbyl group having from 1 to 12 carbon atoms.

12. A composition as claimed in any one of the preceding claims in which E' has an EEW of less than 3200.

13. A composition as claimed in any one of the preceding claims wherein the base is an amine of the formula NR3, each R being independently H, methyl or ethyl, except that not more than one R is H.

14. A composition as claimed in any one of the preceding claims in which the base is triethylamine.

15. A process for making water-thinnable, base-neutralized acidic resins which are convertible to hydrophobic, high performance, thermoset resins, said process comprising: (I) reacting orthophosphoric acid with (1) a polyether epoxide resin E' as defined in any one of Claims 1 to 8 and 12, said reaction being carried out by contacting E' with an orthophosphoric acid source material and from 0 to 25 molecular proportions of water per molecular proportion of H3PO4 provided by said source material, until the fraction of the oxirane groups in E' converted is at least sufficient to render the resulting product water-thinnable when contacted with a base, the amount of orthophosphoric acid included as such in said source material, or obtainable therefrom by hydrolysis, being such as to provide 0.3 or more acidic hydroxyl groups per oxirane group, and (II) contacting the resulting reaction product with at least sufficient of a base which is ammonia or an organic amine to render it water-thinnable.

16. A process as claimed in Claim 15 wherein additionally a vicinal epoxide E2 as defined in Claim 2 is reacted with an orthophosphoric acid source material and contacted with a base in the same manner as the polyether epoxide resin El, the mole ratio of E' to E2 epoxides being from 0.1 to 100.

17. A process as claimed in Claim 15 or Claim 16 wherein dioxane, methyl ethyl ketone, acetone or a mixture of dichloromethane and acetone containing 25 weight percent or less of dichloromethane is employed as a medium for the phosphoric acid/epoxide reaction.

18. A process as claimed in any one of Claims 15 to 17 in which the orthophosphoric acid source material is 100% orthophosphoric acid, the semihydrate 2H3PO4 . H2O or an aqueous solution containing at least 18 wt /O H3PO4.

19. A process as claimed in any one of Claims 15 to 17 in which the orthophosphoric acid source material is an aqueous solution containing 70 to 90 wt% 3PO4.

20. A process as claimed in any one of Claims 15 to 19 in which the amount of orthophosphoric acid source material is such as to provide 0.8 to 1.2 acidic hydroxyl groups per oxirane group.

21. A process as claimed in any one of Claims 15 to 20 in which the reaction temperature is from 110 to 1300C.

22. A process as claimed in any one of Claims 15 to 21 in which the reaction contact time is from 3 to 6 hours.

23. A process as claimed in any one of Claims 15 to 22 in which the base is an organic amine as defined in Claim 13 or Claim 14.

24. Water-thinnable, base-neutralized acidic resins which have been made by a process as claimed in any one of Claims 17 to 23.

25. A water-thinnable, resinous phosphate composition consisting essentially of: (A) resin molecules containing 1,2 - glycol- or beta-hydroxy phosphomonoester groups which are derived from the conversion of the oxirane group in an epoxide represented by one of formulae (a) to (n)

wherein Q, independently, in each occurrence, is

n is an integer of from 0 to 40, r is zero, 1 or 2 and, independently in each occurrence; R' is H, methyl or ethyl, R2 is -Br, -Cl or a C, to C4 alkyl or alkenyl group, R3 is a C1-C4 alkylene or alkenylene group, C(CF3)2 -CO-, SO2, -S-, -0- or a valence bond, and R4 is -Br, -Cl or a C, to C4 alkyl or alkenyl group; (b) a methylol- or alkoxymethyl-substituted phenylglycidyl ether of the following formula

wherein Y is H or a Cl to C4 alkyl or alkenyl group, each YO-CH2- group is either ortho or para to a glycidyloxy group, x is 1, 2 or 3, p is 0 or I and a is 1 or 2, R, independently in each occurrence, is H, methyl or ethyl, R5 is a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, alkylphenyl, phenylkyl, phenoxy, -Br, -Cl group or a

group wherein y is 0, 1 or 2, Y and R are as above defined, T is a C1-C4 alkylene or alkenylene group, C(CF3)2 -SO2-, -S-, -O- or a valence bond, R6 is -Br, -Cl or a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, alkylphenyl, phenalkyl or phenoxy group, and t is 0 or 1; with the proviso that (x+a) cannot exceed 4 and (x+y) is from 2 to 4; (c) a methylol- or alkoxymethyl-substituted, (2,3 - epoxy)propylbenzene of the formula

wherein: b is 1 to 3, d is 0 or 1, R7 is C1-C12 alkyl or

Y' is H or a C, to C4 alkyl or alkenyl group, R' is H, methyl or ethyl, with the proviso that (b+d) cannot exceed 3; (d) di- and trioxides of unsaturated C4 to C28 hydrocarbons containing two or three non-aromatic, carbon-to-carbon double bonds and, optionally, a -Br, -Cl or -F or hydroxy substituent which is not attached to a carbon of any of said double bonds; (e) epoxy ethers of the formula R8-O-R9, wherein each of R8 and R9 is the same or a different monovalent radical deriveable by abstraction of hydrogen from a C3-C12 aliphatic-, alicyclic- or phenalkylene-oxide; (f) 2,3 - epoxypropyl halides or alcohols of the formula

wherein A is -Cl, -Br, or -OH and R is -H, -CH3 or -C2H5; (g) glycol menoethers of the formula

and glycol diethers of the formula

wherein, R is -H, -CH3 or -C2H5, R10 is -H or -CH3, X is -H, -CH3 or -C2H5, g is 1, 2 or 3 and h is 2 or 3; (h) diglycidyl ethers of the formula

wherein R11 is a divalent aliphatic or cycloaliphatic hydrocarbon radical of from 2 to 22 carbons and R is -H, -CH3 or -C2H5, (i) mono or diglycidyl ethers of

(i) mono-, di- or triglycidyl ethers of glycerine; (k) trifunctional aromatic epoxides

wherein Z is

R12 is C1-C2 alkoxy, C1-C6 alkyl or C2-C6 alkenyl, R13 is H, C1-C12 alkyl or C2-C12 alkenyl, R14 is a C1-C8 alkyl, alkenyl, cycloalkyl, cycloalkenyl or aralkyl group, ortho or para to those Z-CH2- moieties on the benzene ring to which said group is attached, R is as previously defined and R15 is a C1-C4 alkylene or alkenylene group or -SO2-; () tetraglycidyl ethers of the formula

wherein R15 is a C1 to C6, divalent aliphatic hydrocarbon radical,

-SO2-, -S-, -0- or a valence bond and Z is

(m) tri- to pentafunctional epoxy novolaks of the formula

wherein p is 1 to 3, R17 is H or -CH2, independently in each occurrence, R18 is an alkylene group of 1 to 4 carbons and

and (n) methylol or alkoxymethyl substituted, oligomeric monoepoxides of the formula

wherein u is 0, 1, 2 or 3, R', independently in each occurrence, is H, methyl or ethyl and R'9, independently in each occurrence, is a C1-C12 alkyl, alkenyl, cycloalkyl, phenyl, phenalkyl or alkylphenyl group, the number ratio of glycol to monoester groups in said molecules being from 0 to 1.3, the proportion of said molecules so derivable from epoxide molecules of formula (a) being from 10 to 100 mole percent and the average EEW of of the epoxide molecules from which said resin molecules are derivable being from 200 to 3200.

(B) from 0 to 25 parts by weight of ortho phosphoric acid per 100 parts of said resin molecules, and (C) a base which is ammonia or an organic amine in such amount that at least enough of the P-OH moieties in said resin molecules are salified thereby to render said molecules dispersible in water.

26. A composition as claimed in Claim 25 wherein the proportion of said resin molecules derived from epoxide molecules of formula (a) is 100 mole percent.

27. A composition as claimed in Claim 25 wherein the proportion of said resin molecules derived from epoxide molecules of formula (a) is from 12 to 50 mole percent and the proportion derived from epoxide molecules of formulae (b) to (n) is trom 88 to 50 mole percent.

28. A composition as claimed in Claim 27 wherein said resin molecules derived from epoxides of formulae (b) to (n) are derived only from epoxides of formulae (b), (c) or (n), or from mixtures thereof.

29. A composition as claimed in Claim 27 wherein said resin molecules derived from epoxides of formulae (b) to (n) are derived only from epoxides of formula (b).

30. A composition as claimed in Claim 27 wherein said resin molecules derived from epoxides of formulae (b) to (n) are derived only from epoxides of formula (c).

31. A composition as claimed in Claim 27 wherein said resin molecules derived from epoxides of formulae (b) to (n) are derived only from epoxides of formula (n).

32. A composition as claimed in Claim 26 wherein said resin molecules are derived only from epoxides of formula (a) in which Q, in each occurrence, is

in which r, R2 and R3 are as defined in Claim 26.

33. A process for making water-thinnable salts of resinous, acidic phosphate esters which are convertible to hydrophobic, high performance, thermoset resins, said process comprising: (I) reacting orthophosphoric acid with (1) a polyether epoxide resin E' consisting essentially of molecules of formula (a) as defined in Claim 26, and necessarily, if the EEW of E' is greater than 3200 or, optionally, Ifthe EEW of E' is less than 3200, with (2) an epoxide E2 which consists essentially of molecules, each of which, independently, either is of a kind represented by formula (a) but has a different value of n than E' or is one of kinds (b) to (n) as defined in Claim 26, said reaction being carried out by contacting E', and any E2 epoxide which is employed, with orthophosphoric acid mixed with 0 to 4 molecular proportions of water per molecular proportion of H3PO4, until essentially all of the oxirane groups originally present remain unreacted, the amount of said acid employed being such as to provide at least 0.7 acidic hydroxyl groups per oxirane group, and the relative amounts of E' and E2 employed being such that the average EEW for E' and E2 combined is from 200 to 3200, and (II) contacting the resulting reaction product with at least enough of a base which is ammonia or an organic amine to render it dispersible in water.

34. A process as claimed in Claim 33 wherein an E2 epoxide is employed and E' and E2 are reacted simultaneously with the phosphoric acid.

35. A process as claimed in Claim 33 wherein an E2 epoxide is employed and E' and E2 are reacted sequentially with the phosphoric acid.

36. A process as claimed in Claim 33 in which El has an EEW of less than 3200 and an E2 epoxide is not employed.

37. A process as claimed in Claim 33 wherein Q in each occurrence is

and r, R and R are as defined in Claim 25.

38. A process as claimed in Claim 37 in which Q, in essentially all occurrences, is either

39. A process as claimed in Claim 32 in which an E2 epoxide is employed and E2 consists essentially of molecules, each of which independently is of formula (b), (c) or (n).

40. A process as claimed in Claim 39 wherein E2 consists essentially of molecules of formula (b) in which Y is -H or -CH, x=2, p=l, R8 is an aliphatic hydrocarbyl group of I to 12 carbons and R6 is -H or CR3.

41. A process as claimed in Claim 40 wherein E2 consists essentially of molecules of the formula

and R5 is an alkyl group of 4 to 9 carbons.

42. A process as claimed in Claim 33 in which E' has an EEW greater than 3200 and E2 is an epoxide of formula (a) having an n value of 3 or less.

43. A process as claimed in Claim 33 in which the phosphoric acid is charged to the reaction as aqueous orthophosphoric acid, of a concentration of from 70 to 90%, and in an amount such as to provide from 0.8 to 3 acid hydroxyls per oxirane group.

44. A process as claimed in Claim 33 wherein dioxane or methyl ethyl ketone is employed as a medium for the acid/epoxide reaction.

45. A process as claimed in Claim 44 in which the medium is methyl ethyl ketone.

46. A process as claimed in Claim 33 in which a medium for the acid/oxirane reaction other than methyl ethyl ketone is employed, the reaction mixture is stirred with water, a volatile organic amine is added as the base, the medium is largely removed, the resulting residue is stirred with enough methyl ethyl ketone to dissolve it and the resulting solution is then stripped of methyl ethyl ketone to yield a stable aqueous dispersion of the amine salt of the acid/epoxide reaction product.

47. A process as claimed in Claim 33 additionally comprising preparing an aqueous dispersion of the base-contacted reaction product, applying said dispersion as a coating on a substrate, heating to effect removal of the water and the ammonia or amine, and curing the resulting dehydrated, deneutralized coating.

48. A process as claimed in Claim 47 wherein an E2 epoxide of formula (b), (c) or (n) is employed in the acid/epoxide reaction, no auxiliary curing agent is added and said deneutralized coating is cured by heating it.

49. A process as claimed in Claim 33 inwhich said organic base is an amine of the formula NR3 , wherein each R20 is H, methyl or ethyl independently, except that not more than one R20 is H.

50. A process as claimed in Claim 49 in which said amine is triethylamine, dimethylamine, trimethyl amine or diethylamine.

51. A product of a process as claimed in any one of Claims 33 to 50.

52. An aqueous dispersion of a composition as claimed in any one of Claims 1 to 14.

53. An aqueous dispersion of a water-thinnable, base-neutralized acidic resin as claimed in Claim 24.

54. An aqueous dispersion of a composition as claimed in any one of Claims 25 to 32.

55. An aqueous dispersion of a product as claimed in Claim 51.

56. A method of coating a substrate involving the use of an aqueous dispersion as claimed in one of Claims 52 to 55.

57. A substrate which has been coated by a method as claimed in Claim 54.

58. A can which has been lined by a method as claimed in Claim 56.

59. A composition as claimed in Claim 2 or Claim 3 when applied as a film or coating on a substrate.

60. A coating of Claim 59 wherein the composition is dehydrated, desalified and cured in place on the substrate by heating.

61. A resin which is the reaction product of orthophosphoric acid and a polyether epoxide resin E' as defined in Claim 1.

62. A resin which is the reaction product of orthophosphoric acid, a polyether epoxide resin E' as defined in Claim 1, and a vicinal epoxide E2 as defined in Claim 2.

63. A resin which is a combination of (a) the reaction product of orthophosphorio acid and a polyether epoxide resin E' as defined in Claim 1, and (b) the reaction product of orthophosphoric acid and a vicinal epoxide E2 as defined in Claim 2.

64. A water-thinnable product obtained by contacting a resin as claimed in any one of Claims 61 to 63 with a base which is ammonia or an organic amine.

65. An aqueous dispersion of a water-thinnable product as claimed in Claim 64.

66. A method of coating a substrate involving the use of an aqueous dispersion as claimed in Claim 65.

67. A substrate which has been coated by a method as claimed in Claim 66.

68. A can which has been lined by a method as claimed in Claim 67.

69. A resin as claimed in any one of Claims 61 to 63 which is in a cured state.

70. A can lined with a cured resin as claimed in Claim 69.

71. A process as claimed in Claim 15 in which the amount of H3PO4 provided to the reaction is 1 part or less by weight per 100 parts of E'.

72. A process as claimed in Claim 15 in which the overall ratio of acidic hydroxyls to oxirane groups is from 0.4 to 1.0.

73. A product of a process as claimed in Claim 15 in which E' has an EEW of less than 3200.

74. A product of a process as claimed in Claim 13 in which E' is a diglycidyl ether derivable from adductive polymerization of bisphenol-A with a diglycidyl ether of bisphenol-A.

75. A product as claimed in Claim 74 which has been made water-thinnable by neutralization with ammonia or an organic amine.

76. A neutralized product as claimed in Claim 75 when thinned with water to a resin content of 50 wt% or less.

77. A thermoset resin coating prepared from the water-thinned product claimed in Claim 76.

78. A composition as claimed in Claim 1 substantially as hereinbefore described in any one of the Examples.

79. A process as claimed in Claim 15 substantially as hereinbefore described in any one of the Examples.