AU2507292A - Internally flexibilized advanced epoxy resin compositions and coatings therefrom - Google Patents

Description

INTERNALLY FLEXIBILIZED ADVANCED EPOXY RESIN COMPOSITIONS AND COATINGS

THEREFROM

The invention relates to internally flexibilized advanced epoxy resin compositions flexibilized with internal polybutylene glycol units, and a process for the preparation of such internally flexibilized advanced epoxy resins. The invention further relates to coatings prepared from such internally flexibilized advanc epoxy resins, such coatings are useful in cathodic electrodepositions, powder coating applications, marine and maintenance and in food and beverage applications.

Advanced epoxy resin compositions are used in a variety of applications, such as in coatings compositions in several fields, for example in cathodic electrodeposition, powder coating of pipes and structural elements, in liquid coating compositions for food and beverage cans and marine and maintenance applications. Advanced epoxy resin based coatings have advantageous properties such as adhesiveness, strength, hardness and chemical resistance. Unfortunately, cured advanced epoxy resin compositions suffer from a lack of flexibility, which can have a negative effect on other properties such as protection of substrates from corrosion.

A representative use of advanced epoxy resins compositions which exhibits such problems is the field of cathodic electrodeposition. Cathodic electrodeposition of a film composed of an amine modified epoxy resin, crosslinker, pigment and optionally other resinous components onto an electrically conductive article is an imoortant industrial process. It constitutes the usual manner i which automobile and truck bodies as well as appliance and other large complex metallic surface bodies are protected against corrosion. In oerformmg the eiectr odeoosition, the conductive article, article to be coated, forms one electroαe and is ^•mmersed a coating Dath made from an aqueous diSDersion of the fi-η . forming amine modified epoxy ^resm and other comoonents. An electrical current is oassed between the article and the counter electrode in the electrodeposition bath. A charge on the article causes deposition of the resins and other components in tne batn on the article to be coated so as to produce the electrodeposited film The deposited film is then baked or otherwise hardened to yield a coating of a substantially uniform thickness and protective characteristics

A number of advances in the protective properties of elect, odeposit resin systems have been described in the patent literature For example, US Patent Nos 4, 104,147; 4,148,772; 4,420,574, 4,423,166, 3,962,165, 4,071 ,428, 4,101 ,468, 4,134,816, 3,799,854, 3,824,1 1 1 , 3,922,253, 3,925,180, 3,947,338, 3,947,339, describe methods for improvement of the principal resin properties Amine modified epoxy resins used in the coatings disclosed in these patents can be flexibilized by extending the molecular length of the aromatic diepoxide starting material with polyois, polyamines, polyether polyois, polyester polyois and other similar types of extension agents US Patent 3,839,252 describes modification with polypropylene glycol US Patent 3,947,339 teaches modification with poiyesterdiols or polytetr amethylene glycols US Patent 4,419,467 describes still another modification with diois derived from cyclic polyois reacted with ethylene oxide In those embodiments wherein polyether polyois and polyester polyois have been used to modify the advanced epoxy resins, it has been difficult to efficiently and effectively incorporate such materials into the backbone of the resin Tertiary amines or strong bases are required to effect the reaction between the primary alcohols and the epoxy groups involved Furthermore, these reactions require long cook times and are subject to gellation because of competitive polymerization of the epoxy groups σy the base catalyst In addition epoxy resins containing low levels of chlorine are required to prevent deactivation of this catalyst

European Patent Application 300,504A discloses the preparation of flexibilized epoxide compounds by reacting an aromatic diol with diepoxides which are diglycidyl ethers of aromatichydroxy compounds, or a bιs-(labιle hydrogen functiona zed) alkoxy arylene compound European Patent Application 315, 164 discloses a coating resin composition which comprises the reaction product of a diepoxide compound which is a diglycidyie ther of a bisphenol A (bιs-(4-hydroxy phenyl)propane) initiated polyalkylene oxide, a bisphenol, optionally a bisphenol diglycidyie ther, and an amine, having an active nydrogen It is disclosed therein that the bisphenol A initiated polyalkylene oxide diepoxide ^res_lts in an improved electrodeDOSi tion coating Commonly assigned patent application EP 253,405 discloses an advanced epoxy cationic resin DΓ epar ed by reacting in the presence of a suitable catalyst (A) a composition comprising (1) at least one diglycidyl etner of a polyol and (2) at least one diglycidyl ether of a oihydπc Dnenol w.th (B) at least one dinydπc σnenol and ODtionally (C) a monofunctional capping agent Components (A) ana (B) are e Dioyeα m such quantities that the resultant epoxy resin has an average eooxide weight from 350 to 10 000 The resins disclosed exhibit some flexibility problems and do not provide superior anticorrosion properties. Additionally, some of the processes disclosed for preparing the resins do not efficiently incorporate the polyalkylene glycol containing diepoxides into the backbone of the advanced resins.

In electrodeposition it is desirable that the resins in the coating have a low viscosity to facilitate processing and control of the coating thickness. It is also desirable that such coatings demonstrate low water permeability as this property is important in the inhibition of corrosion. Additionally it is desirable that such coatings demonstrate good flexibility. The problem is that as the resin viscosity is lowered and the coating flexibility is increased, the water permeability of the coating is usually also increased. What i«. needed are resins for use in coatings, including electrodeposition coatings, which exhibit lo _r viscosities, result in coatings with higher flexibility and lower water permeability. What is further needed, is an advanced resin which has efficiently incorporated therein the flexibilizing agents. What is further needed is a process which allows efficient incorporation of the fiexibiiizing agent into the backbone of the advanced epoxy resin.

The invention relates to flexibilized advanced epoxy resins comprising the residue of A. one or more polyglycidyl ethers of a water or di- or trihydroxy substituted Cι_6 hydrocarbon initiated polybutylene glycol;

B. one or more polyaromatichydroxy compounds; and

C. one or more polyglycidyl ethers of polyaromatichydroxy compounds;

wherein substantially all of the glycidyl ether moieties of the polyglycidyl ethers of polybutylene glycol are bound to the polyaromatichydroxy compounds through the reaction product of the glycidyl ether moieties with the aromatichydroxy moieties; each polyaromatichydroxy compound is bound to at least one polyglycidyl ether of polybutylene glycol or to at least one polyglycidyl ether of a polyaromatichydroxy compound through the reaction product of an aromatichydroxy moiety with a glycidyl ether moiety; most of the polyglycidyl ethers of polyaromatichydroxy compounds are bound to at least one polyaromatichydroxy compound through the reaction product of glycidyl ether moiety and an aromatichydroxy moiety; each residue of a polyglycidyl ether of polyaromatichydroxy compound is bound to at least one polyaromatichydroxy compound through the reaction of a glycidyl ether moiety and an aromatichydroxy moiety;

wherein the mole ratio of polyaromatichydroxy compound to polyglycidyl ether of polybutylene glycol is at least 2.0 to 1.0; and sufficient polyglycidyl ether of polyaromatichydroxy compound is present in the resin such that the terminal moieties of the resin are glycidyl ether moieties from the polyglycidyl ethers of polyaromatichydroxy compounds.

In another aspect the invention is a process for the preparation of such flexibilized advanced epoxy resins comprising

A. reacting a polyglycidyl ether of a di- or tn- hydroxy Cι_6 hydrocarbon or water initiated polybutylene glycol with two or more moles of a polyaromatichydroxy compound per mole of polyglycidyl ether of polybutylene glycol under conditions such that substantially all of the glycidyl ether moieties of the polyglycidyl ether of polybutylene glycol react with aromatichydroxy moieties of the polyaromatichydroxy compounds;

B thereafter reacting the reaction product from A with an excess of one or more polyglycidyl ethers of polyaromatichydroxy compounds, optionally one or more polyaromatichydroxy compounds, and optionally one or more chain terminators, under conditions such that the aromatichydroxy moieties react with the glycidyl ether moieties wherein the terminal functional moieties of the product are glycidyl ether moieties.

In another aspect the invention relates to flexibilized advanced epoxy resins prepared by the above-described process In yet another aspect the invention is directed to advanced epoxy cationic resins having a charge density of from 0.2 to 0.6 milliequivalents of cationic charge per gram of resi n, wherein the terminal epoxy moieties of the above-described resins have been reacted with a nucleophile and treated to render the resulting moieties cationic.

The advanced epoxy resins of the invention demonstrate improved flexibility and improved corrosion protection of substrates coated with such compositions as compared to conventional resins. The flexibilized advanced epoxy resin compositions of the invention and the process for preparation of the resin also demonstrate a more efficient incorporation of the flexibilizing agent into the backbone of the resin. The flexibilized advanced eooxy resins of the invention demonstrate improved elongation and imσa resistance along with exceptional combination of elongation, impact resistance, and corrosion resistance as compared to conventional resins.

A major advantage of the invention is the efficient incorporation of an improved fiexibilizing agent into tne internal backbone of the advanced eooxy resins Thus the backbone of the flexibilized eooxy resin of this invention contains at least one unit of the flexibilizing component in its interior. The fiexibiiizing unit is the residue of a polyglycidyl ether of a water or di- or ^ri- hydroxy substituted C_!.6 ny rocarDon initiated polybutylene glycol, which means herein that the glycidyl ether moieties of such compound have been reacted with aromatic hydroxy I groups so as to incorporate such polybutylene glycol into the backbone of the flexibilized advanced epoxy resins. The flexibilizing agent is prepared by reacting water or a di- or tri- hydroxy substituted C- .6 hydrocarbon with butylene oxide units, so as to react the hydroxy units or water with the butylene oxide, thereby forming a polybutylene glycol with a central unit comprising oxygen or the residue of the di- or tri- hydroxy substituted Cι_6 hydrocarbon. Thereafter the terminal hydroxy moieties of the polybutylene glycol are reacted with an epihalohydrin to form terminal glycidyl ether moieties. Such reactions are well-known to those skilled in the art. Polybutylene glycol as used herein refers to compounds which contain more than one butylene oxide unit within the backbone, and includes compounds wherein one butylene oxide unit is added to each active hydrogen unit of the initiator.

Included among the initiators for the flexibilizing unit are water, ethylene glycol, propyiene glycol, butane diols, such as 1 ,4 butane diol, trimethyol propane, neopentylglycol and glycerol. The most preferred initiator is water. Preferably, the polyglycidyl ether of polybutylene glycol has a molecular weight of 1 0 or greater, most preferably 200 or greater and most preferably 300 or greater. Preferably the polyglycidyl ether of polybutylene glcyol, has a molecular weight of 2000 or less, more preferably 1000 or less, and most preferably 600 or less. The molecular weights referred to here are number average molecular weights. The flexibilized advanced epoxy resins of this invention preferably contain 5 percent or greater by weight of the residue of the glycidyl ethers of polybutylene glycol in the backbone, and more preferably 10 percent or greater. Preferably, the flexibilized advanced epoxy resins of this invention contain 50 percent or less by weight of the residue of polyglycidyl ethers of polybutylene glycol in the backbone, more preferably 30 percent or less by weight. In a preferred embodiment, the glycidyl ethers of polybutylene glycol correspond to formula 1 :

wherein R is independently in each occurrence hydrogen, methyl or ethyl with the proviso that for each

unit either both of R are methyl or one R is ethyl and the other is hydrogen; T is independently in each occurrence a direct bond or the moiety

R' is independently in each occurrence hydrogen or a C alkyl moiety; Z is independently in each occurrence oxygen or

X is independently in each occurrence a straight or branched chain Cι_e alkyl moiety; a is independently in each occurrence a positive real number of 1 or greater; b is independently in each occurrence 2 or 3 Z is preferably oxygen. X is or efer ably a straight or branched chain Cι._ι alkyl moiety. Preferably, a is a real number of from 1 to 16; more preferably from 1 to 8 and most preferably of from 2 to 5. Preferably b is 2.

The initiator used in this invention preferably is water or corresponds to Formula 2:

wherein X and b are as described hereinbefore.

The polyglycidyl ethers of polybutylene glycol are reacted with polyaromatichydroxy compounds Polyaromatichydroxy compounds referred herein to compounds which on average contain more than one hydroxy group and which comprises a nydrocarbon backbone containing aromatic moieties, wherein the hydroxy moieties are bound to aromatic moieties directly Preferably the polyaromatichydroxy hydrocarbons have two or more aromatic bound hydroxy groups The polyaromatichydroxy compounds can be further substituted on the hydrocarbon backbone by halogen moieties. Among preferred classes of Dolyaromatichydroxy comπounos are the bispnenols, halogenated bisDhenols, hydrogenated Dispnenois, ana novolac resins, ^• e the reaction product of Dhenols and simple aldehydes, preferably formaldehyde ana hydroxy benzaidehyde Preferred polyaromatichydroxy compounds useful in this invention correspond to formula 3: A — (OH)_c

wherein

Ar is an aryl moiety; aryl moiety substituted with an alkyl or halo moiety; a polyaryl moiety wherein the aryl moieties are connected by direct bonds, alkylene, haloalkylene, cycloalkylene, carbonyl, sulfonyl, sulfinyl, oxygen, or sulfur moieties, such polyaryl moieties being optionally substituted with an alkyl or halo moiety; or the oligomeric reaction product of an aldehyde and phenol; and c is a positive real number greater than 1.

More preferred polyaromatichydroxy compounds include those corresponding to formulas 4 and 5:

wherein;

R2 is separately in each occurrence C1-3 alkyl or a halogen;

R3 is separately in each occurrence G.-o alkylene, Ci.fo haloalkylene, C_..**o cycloalkylene, carbonyl, sulfonyl, sulfinyl, oxygen, sulfur, a direct bond or a moiety corresponding to the formula

R^Δ is independently in each occurrence Cι_ιo alkylene or C5.50 cycloalkylene;

Q is independently in each occurrence a C-.no hydrocarbyl moiety;

Q' is independently in each occurrence hydrogen, cyano, or a C-,-_. alkyl group; m is independently in each occurrence an integer of 0 to 4; m' is independently in each occurrence an integer of from 0 to 3; p is a positive real number of 0 to 10.

R³ is preferably C].3 alkylene, C₁-3 haloalkylene, carbonyl, sulfur, or a direct bond. R3 is more preferably a direct bond, G.3 alkylene, or fluormated propylene ( = C(CF3)₂-). R³ is most preferably propylene. R² is preferably methyl, bromo or chloro; and most preferably methyl or bromo. R⁴ is preferably C1.3 alkylene or polycyclic moiety corresponding to the formula

wherein t is an average number from 1 to 6 inclusive, preferably 1 to 3, most preferably 1. Preferably, m and m^" are independently an integer of 0 to 2. Preferably, p *s a positive real number of 0 to 8; and more preferably _ to 4. p represents an average number, as the compounds to which it refers are generally found as a mixture of compounds with a distπDution of the units to which p refers. Cycloalkylene as used herein refers to monocyclic and poiycyciic hydrocarbon moieties.

The most preferred class of polyar omatichdr oxy compounds are the dihydroxy phenols. Preferable dihydroxy phenols include those whicn contain substituents that are πon- reactive with the phenolic groups. Illustrative of such phenols are 2,2-bis(3,5-dibr omo-4- hydroxyphenyl) propane; 2,2-bis(3,5-dibromo-2,4'-hydroxyphenyl) propane; 2,2-bis(4- hydroxyphenyl) propane; 2,2-bis(2,4'-hydroxyphenyl) propane; 2,2-bis(3,5-dichloro-4- hydroxyphenyl) propane; 2,2-bis(3,5-dichloro-2,4'-hydroxyphenyl) propane; bis (4- hydroxyphenyl) methane; bis (2,4'-hydroxyphenyl) methane; 1 ,1-bis(4-hydroxyphenyl)-1- phenyl ethane; 1 ,1-bis(2,4'-hydroxyphenyl)-1-phenyl ethane; 1 ,1-bis(2,6-dibromo-3,5- dimethyl-4 hydroxy phenyl) propane; bis (4-hydroxyphenyl) sulfone; bis (2,4'-hydroxyphenyl) sulfone; bis (4-hydroxyphenyl) sulfide; bis (2,4'-hydroxyphenyl) sulfide; resorcinol; hydroquinone; and the like. The preferred dihydroxy phenolic compounds are 2,2-bis(4- hydroxyphenyl) propane, 2,2-bis(2,4'-hydroxyphenyl) propane (a mixture of the two is commonly refe-^red to as bisphenol A).

As used herein haloalkyl refers to a compound with a carbon chain and one or more of the hydrogens replaced with a halogen, and includes compounds where all of the hydrogen atoms have been replaced by halogen atoms. Alkylene as used herein refers to a divalent alkyl moiety.

The term hydrocarbyl means any aliphatic, cycloaliphatic, aromatic, aryl substituted aliphatic or cycloaliphatic, or aliphatic or cycloaliphatic substituted aromatic groups. The aliphatic groups can be saturated or unsaturated. Likewise, the term hydrocarbyloxy means a hydrocarbyl group having an oxygen linkage between it and the carbon atom to which it is attached. Polyaryl moiety as described herein refers to compounds which contain more than one aromatic ring which may be fused, bonded by direct bond, or connected by alkylene, haloalkylene, cycloalkylene, carboxyl, sufonyl, sulfinyl, oxygen or sulfur moieties.

The term residue as used herein refers to the portion of a starting material remaining in the final product after completion of the reaction. The term residue of a polyaromatichydroxy compound means herein that a polyaromatichydroxy compound has been incorporated into the backbone of the flexibilized advanced epoxy resin wherein the aromatichydroxy moieties have reacted with glycidyl ether moieties of the glycidyl ether of polybutylene glycol, or the glycidyl ether moieties of a glycidyl ether of an aromaticnydroxy compound. In a preferred embodiment, the polyaromatichydroxy compounds are nominally dihydroxy aromatic compounds meaning that the dihydroxy compounds are a mixture of compounds resulting from the preparation process, and on average the compounds present have near two hydroxy moieties per molecule. The residue of polyglycidyl ethers of poiyaromatic hydrocarbon means heretⁿ that at least one of the glycidyl ether moieties has reacted with an aromatichydroxy moiety, wherein the polyaromatichydroxy compound may be further reacted with a polyglycidyl ether of a polybutylene glycol The resins of this invention preferably have terminal glycidyl ether moieties which are derived from the glycidyl ethers of polyaromatichydroxy compounds A small portion of the flexibilized advanced epoxy resins of this invention contain polyglyciyl ethers of poiyaromatic hydrocarbons that have not reacted with an aromatichydroxy moiety. Generally these materials are not removed prior to utilization

Polyglycidyl ether of a polyaromatichydroxy compound means a hydrocarbon compound containing one or more aromatic moieties, wherein more than one epoxy (1 ,2 glycidyl ether) moiety is bound to the aromatic moieties In another embodiment it refers to a mixture of compounds which contains, on average, more than one epoxy moiety per molecule bound to aromatic moieties Polyglycidyl ether of a polyaromaticnydroxy compound as used herein includes partially advanced epoxy resins i e the reaction oτ a polyglycidyl ether of a polyaromatichydroxy compound and one or more polyaromatichydroxy compounds, whe^reιn the reaction product has an average of more than one unreacted epoxide unit per molecule

Polyglycidyl ethers of a polyaromatichydroxy compounds (polyepoxides) are prepared by reacting an epihalohydπn with a polyaromatichydroxy compound The preparation of such compounds is well known in the art See Kirk-Othmer Encyclopaedia of Chemical Technology 3rd Ed Vol 9 pp 267-289, "The Handbook of Epoxy Resins" by H. Lee and K. Neville (1967) McGraw Hill, New York, and US Patents 2,633,458, 3,477,990; 3,821 ,243, 3,907,719, 3,975,397; and 4,071 ,477

The epihalohydπns correspond to formula 6

wherein

Y is a halogen, preferably cnloro or bromo, and most preferably cnloro, and R is as previously defined The polyglycidyl ethers of polyaromatichydroxy compounds useful in the invention preferably correspond to formula 7

wherein Ar, R^' and c are previously defined. R' is preferably hydrogen or methyl. Preferably, c is 5 or less, more preferably from 1 to 3.

The polylycidyl ethers of polyaromatichydroxy compounds more preferably correspond to one of formulas 8 or 9:

8

wherein R¹, R², R³, R⁴, m, and m' are as defined previously; πs a positive real number of 0 to 40, and s is a positive real number of 0 to 10 Preferably, r is a positive real number of 0 to 10, and most preferably 1 to 5 Preferably, s is a positive real number of 0 to 8; and most preferably 1 to 4. All of the variables referred to herein as positive real numbers, i.e r and s, are average numbers as the compounds referred to contain a distribution of units

Preferable polyglycidyl ethers of polyaromatichydroxy compounds are the glycidyl ethers of dihydroxy phenols, bisphenols, halogenated bisphenols, alkylated bisphenols, tπspheπols, phenol-aldehyde novolac resins, halogenated phenol-aldehyde novolac resins, alkylated phenol-aldehyde novolac resins, hydrocarbon-phenol resins, hydrocarbon- halogenated phenol resins, or hydrocarbon-alkylated phenol resins, or any combination thereof and the like Even more preferable polyglycidyl ethers of polyaromatichydroxy compounds include, for example, the diglycidyl ethers of resorcinol, catechol, hydroquinone, bisphenol, bisphenol A, bisphenol AP (1 , 1-bιs(4-hydroxylphenyl)-1-phenyl ethane), bisphenol F, bisphenol K, tetrabromobisphenol A, phenol-formaldehyde novolac resins, alkyl substituted phenol-formaldehyde resins, phenol-hydroxybenzaidehyde resins, cresol- hydroxybenzaldehyde resins, dicyclopentadiene-phenol resins, dicyclopeπtadiene-substituted phenol resins tetramethylbi phenol, tetramethyl-tetrabromobiphenol, tetramethyltπbrorriobiphenol, tetrachlorobisphenol A, tetrabromobisphenol A, any combination thereof and the like Preferably the polyglycidyl ether of the polyaromatichydroxy compounds is a nominally diglycidyl ether of a polyaromatichydroxy compound, meaning that the actual materials used are a mixture of compounds resulting from the process for preparation wherein the average number of glycidylether moieties per molecule approaches two

Optionally the advanced flexibilized epoxy resins of this invention can contain the residue of a chain terminator In practice a chain terminator is a material which has only one reactive moiety containing an active hydrogen atom Such chain terminator functions to reduce the molecular weight of the proposed material and are well known in the art. An example of a preferable chain terminator is paratertiarybutyl phenol

In the pre^ferred embodiment wherein the polyaromatichydroxy compound is a nominally diaromatichydroxy compound, and the polyglycidyl ether of a polyaromatichydroxy compound is nominally a digiycidyi ether of a α aromatichydroxy compound, the advanced flexibilized resins of this invention correspond to formula 10

' wherein

B is independently in each occurrence

E is independently in each occurrence a moiety according to one of the formulas

— CH₂TCHCH₂ or

V 0

d is independently in each occurrence a number of from 0 to 2; 5 e is independently in each occurrence 0 or 1 ; and Ar, R, T, Z, X, a, b and c are as defined hereinbefore.

In one preferred embodiment of the invention, the flexibilized advanced epoxy resin are converted to flexibilized advanced epoxy cationic resins which have a charge density 0 of from 0.2 to 0.6 milliequivalents of cationic charge per gram of resin. Such resins are prepared by reacting the terminal glycidyl ether moieties with a nucleophile and thereafter converting the reaction product to cationic species. Nucieophiles useful for performing this reaction are well-known to those skilled in the art. Preferred nucieophiles are monobasic neteroaromatic nitrogen compounds, tetraflower alkyl) thiόureas, sulfides corresponding .to formula 1 1 : ; R6-S-R6 1 1

amines corresponding to formula 12: R7-N-R8 12

R8 or phosphines corresponding to formula 13 R9-P-R9 13

R9 wherein,

R⁶ is independently i n each occurrence lower alkyl, hydroxy lower alkyl or two of R^ may combine as one 3 to 5 carbon atom alkylene radical thereby forming a heterocycloalkylene moiety,

R⁷ is independently in each occurrence hydrogen, hydroxyalkyl, lower alkyl, aralkyl or aryl;

R⁸ is independently in each occurrence hydrogen, lower alkyl, hydroxy lower alkyl, the moiety

R1 1 _R10— N = C<

^X R1 1 or two of R⁸ may combine to form an alkylene radical having from 3 to 5 carbon atoms; R⁹ independently in each occurrence lower alkyl, hydroxy lower alkyl or aryl, R¹0 is independently in each occurrence a C_2-ιo alkylene group, R^{1 1} is independently in ea"ch occurrence lower alkyl

Preferably the nucleophile is an amine, more preferably a primary or secondary amine

Representative nucleophilic compounds are pyπdine, nicotinamide, qumoline, isoquinoline, tetramethyl thiourea, tetraethyl thiourea, hydroxyethylmethyl sulfide, hydroxyethylethyl sulfide, dimethyl sulfide, diethyl sulfide, di-n-propyl sulfide, methyl-π-propyl sulfide, methylbutyl sulfide, dibutyl sulfide, dihydroxyethyl sulfide, bis-hydroxybutyl sulfide, tπmethylene sulfide, thiacyclohexaπe, tetrahydrothiophene, dimethyl amine, diethyl amine, dibutyl amine, 2-(methy!amιno)ethanol, diethanolamine, N-methylpipeπdine, N- ethylpyrroliαone, N-hydroxyethylpyrro dine, tπmethylphosohine, tπethyl-phosphine, tπ-n- butvl-phosohine, tπmethylamine, tπetnylamme, tri-n-propylamine, tπ-isobutyiamine, hydroxyethyl-dimethvlamine, butylαimethyiamine, tπhyαroxyethyiamine, tπpnenylphospnorus, and N,N N-αimetnyipnenethylamine ana the ketimine derivatives of polyammes containing secondary and primary ammo groups such as those produced by the reaαioπ of αiethyiene tnamine or N-amiπoethylpiperazine with acetone, methyl ethyl ketone or methylisooutyl ketone In a preferred embodiment the nucleophile is a primary or secondary amine, the polyaromatichydroxy compound is a diaromatichydroxy compound, and the polyglycidyl ether of a polyaromatichydroxy compound is a diglycidyl ether of a diaromatichydroxy compound, and such compounds preferably correspond to the following formula 14:

wherein: G is independently in each occurrence a moiety according to one of the formulas:

— CH₂TCHCH₂ N ^*-(R7)(R8)₂ CH₂TCHCH₂-0-H

OH ^A" (R7)(R8)₂ N^*A- or

A- is the anion of an acid as described hereinafter; and Ar, B, R, R7, R8_f T, Z, X, a, b, c, d and e are as described hereinbefore.

The flexibilized advanced epoxy resins of this invention preferably exhibit a weight average molecular weight of 900 or greater, more preferably 1200 or greater, and most preferably 1500 or greater. The flexibilized advanced epoxy resins of this invention preferably have a molecular weight of 50,000 or less, more preferably 30,000 or less, anc¹ most preferably 20,000 or less. The flexibilized advanced epoxy resins of this invention prefers jiy have an epoxy equivalent weight (EEW) of 450 or greater, more preferably 600 or greater, and most preferably 800 or greater. The flexibilized advanced epoxy resins of this invention preferably have an EEW of 5,000 or less, more preferably 4,000 or less, and most preferably 3,000 or less.

The inventors have recognized that tne reaαivity of a polyglycidyl ether of a polybutylene glycol with a polyaromatichydroxy compound is much iower than the reactivity of a polyglycidyl ether or a polyaromatichydroxy compound with a polyaromatichydroxy compound. Therefore, unless the process conditions are carefully chosen, it is difficult to efficiently incorporate the polyglycidyl of a polybutylene glycol into the internal structure of and advanced epoxy resin. The process of this invention involves first reaαing the glycidyl ether of a water or di- or tri- hydroxy substituted C-.e hydrocarbon initiated polybutylene glycol with the polyaromatichydroxy compound under conditions such that substantially all of the glycidyl ether moieties on the polyglycidyl ether of the polybutylene glycol are reaαed with aromatichydroxy groups. In the second step the reaction product is reacted with a polyglycidyl ether of a polyaromatichydroxy compound under conditions such that the terminal aromatichydroxy moieties of the reaction product reaα with the glycidyl ether moieties of the polyglycidyl ether of the polyaromatichydroxy compound, such that the terminal groups of the flexibilized epoxy resin are primarily glycidyl ether moieties. Optionally, additional polyaromatichydroxy compounds may be present in the second step to facilitate the further advancement of the flexibilized epoxy resin. If desired a known chain terminator may be present in the reaαion mixture in small quantities.

In the first step, the polyglycidyl ether of the polybutylene glycol is contaαed with the polyaromatichydroxy compound neat, in the absence of solvent, or in the presence of an organic solvent which demonstrates low affinity for water. Such solvents include aromatic hydrocarbons, mixtures of aromatic hydrocarbons and alkanols, glycol ethers and ketones. It is advantageous to include epoxy resin advancement catalyst, such as compounds containing amine, phosphine, heterocyclic nitrogen, ammonium, phosphonium, arsonium, or sulfonium moieties. Preferred catalysts are the phosphonium compounds. In the embodiment where the catalyst is a phosphonium or an amine preferably 500 ppm (parts per million) or more of the catalyst is present, more preferably 700 ppm or more. Preferably such catalyst is present in amounts of 3,000 ppm or less, more preferably 2000 ppm or less. Thereafter the reaction mixture is heated until an exotherm begins, generally at from 140 to 150°C Preferably, the temperature of the mixture is increased at a rate of from 1 to 2°C per minute until the exotherm begins. The temperature is maintained at levels at which the reaαion continues, until the reaction is completed. In those embodiments wherein a phosphonium catalyst is used a reaαion generally stops itself. Where other catalysts are used, the reaction may be quenched by cooling. The reaction time is dependent upon the concentration of catalyst, materials present, presence of solvent and the reaαivity of materials. Preferably reaαion times are 15 minutes or greater, more preferably 30 minutes or greater. Preferably reaαion times are 4 hours or less, and more preferably 3 hours or less In a preferred embodiment, the amount of polyaromatichydroxy compound contaαed with the polyglycidyl ether of the polybutylene glycol is sufficient to rea with ali of the glycidyl ether moieties of the polyglycidyl ether of polybutylene glycol. Preferably two moles of polyaromatichydroxy material or greater is present per mole of polyglycidyl etne^r of polybutylene glycol. In some embodiments it may be advantageous to nave a significant excess of polyaromatichydroxy material where such material would be advantageous in further advancing the reaαion product in the second step. Once the reaction is complete, the reaction product may be recovered from the reaction mixture, or alternatively and preferably the polyglycidyl ether of the polyaromatichydroxy compound is thereafter added to the reaction mixture and the second step of the reaction is performed.

In the preferred embodiment where a diaromatichydroxy compound is reacted with the polyglycidyl ether of the polybutylene glycol based material the reaction product of the first step preferably corresponds to Formula 15:

15 wherein Z, T, R, R¹, Ar, a, and b are as hereinbefore defined.

In the second step of the reaction, the reaction product of the first step is contacted with a polyglicyidyl ether of a polyaromatichydroxy compound, and additional polyaromatichydroxy compound and/or chain terminator. Preferably, the molar amount of polyglycidylether of a polyaromatichydroxy compound is present in a ratio of greater than 1.0 as compared to the moles of the above-mentioned reaction product of the first step and more preferably 1.5 moles or greater. Thereafter, the mixture is heated until exotherm occurs. Optionally, catalyst for the advancement of epoxy resins may be present. Alternatively, a sufficient amount of catalyst may be introduced in step 1 , such that no further catalyst need to be added in the second step. The reactants in the second step may be reacted neat or in the presence of a solvent. Solvents which may be used are those which are typically used as solvents for epoxy advancement reactions. A reaction in solvent may be advantageous wherein heat control is desired. The advancement reaction is preferably performed at a temperature of 130°C or above, as below 130° the reaction time is too slow. Preferably the reaction is performed at a temperature of 230°C is, the polymer reacts to fast above such temperature and unwanted colors may be formed α_. to the presence of oxidated byproducts. More preferably the reaction temperature is 180°C or below. The temperature which may be used for the reaction depends on whether or not a solvent is used, and its nature. The reaction mixture is preferably heated at a rate such that the temperature increases from 1 to 2°C per minute until exotherm is achieved. Thereafter elevated temperatures are maintained until the desired molecular weight and epoxy equivalent weights are reached. The Dolyepoxide advancement reaction is allowed to proceed for a time sufficient to result in substantially complete reaction, preferably 15 minutes or greater, more preferably 30 minutes or greater. Preferably the maximum reaction time is 10 hours or less and more preferably 2 hours or less. The flexibilized advanced epoxy resins of this invention can thereafter be recovered and formulated for use in various coatings applications The flexibilized advanced epoxy resins of the invention may be recovered in a semi-solid or solid state by means well known in the art

The coating compositions which can incorporate the flexibilized epoxy resins of this invention include powder coating compositions, food and beverage can coating compositions and ambient cure coatings useful in industrial maintenance applications. In those embodiments where the resin will be used in marine or industrial maintenance applications, powder, or food and beverage can coatings, the resin may be recovered and then converted to a form useful for such coatings

In one preferred embodiment, the flexibilized advanced epoxy resins of this invention are converted to cationic resins *or use in cathodic electrodeposition coatings by reaαmg at least some of the glycidylether moieties of the resin with a nucleophilic compound and adding an organic acid and water at some point during the preparation It is also possible to rea at least some of the glycidyl ether moieties with a nucleophile salt formed by prereaαmg the nucleophile with the organic acid

Substantially any organic acid, especially a carboxylic acid, can be used in the conversion reaαion to form onium salts so long as the acid is sufficiently strong to promote the reaction between the nucleophilic compound and the glycidyl ether moieties of the resin In the case of the salts formed by addition of acid to a secondary amine/epoxy resin reaction product, the acid should be sufficiently strong to protonate the resultant tertiary amine produα to the extent desired Monobasic acids are normally preferred (H +A-) Preferable organic acids include, for example, alkanoic acids having from 1 to 4 carbon atoms (e g , acetic acid, propionic acid, etc ), alkenoic acids having up to 5 carbon atoms (e g , acrylic acid, methacrylic acid, etc) hydroxy-funαional carboxylic acids (e g , glycolic acid, laαic acid, etc ) and organic sulfonic acids (e g , methanesulfonic acid), and the like Presently preferred acids are lower alkanoic acids of 1 to 4 carbon atoms with laαic acid and acetic acid being most preferred The anion can be exchanged, or course, by conventional anion exchange techniques See, for example, US Patent 3,959, 106 at column 19 Preferable anions are chloride, bromide, oisulfate, bicarponate nifate, dinydrogen phosphate, laαate and alkanoates of 1-4 carbon atoms Acetate and laαate are the most preferred anions

The conversion reaαion to form cationic resins is normally conduαed by blending the reaαants together Gooα results can be acnieved by using substantially stoichiometπc amounts of reaαants although a slight excess or defioency of the epoxy- containing resin or the nucleophilic compounds can oe usec Witn weak acids, useful ratios of the reactants range from 0.5 to 1.0 equivalent of nucleophilic compounds per glycidyl ether moiety of the resin and for organic acids from 0.5 to 1.1 equivalents of organic acid per glycidyl ether moiety. These ratios, when combined with the preferred epoxide content resins described above, provide the desired range of cationic charge density required to produce a stable dispersion of the coating composition in water. With still weaker acids a slight excess of acid is preferred to maximize the yield of onium salts. When the nucleophilic compound is a secondary amine, the amine-epoxy reaction can be conducted first, followed by addition of the organic acid to form the salt and thus produce the cationic form of the resin.

For the onium-forming reactions, the amount of water present can be varied so long as there is sufficient acid and water present to stabilize the cationic salt formed during the course of the reaction, preferably water is present in amounts of from 5 to 30 moles per epoxy equivalent. It is advantageous to include minor amounts of organic solvents in the reaction mixture, the presence of which facilitates contact of the reactants and promotes the reaction rate. One preferred class solvents are the monoalkyi ethers of the C_2- alkylene glycois, which includes the monomethyl ether of ethylene glycol, the monobutyl ether of ethylene glycol, etc. When the desired degree of reaction is reached, any excess nucleophilic compound can be removed by standard methods, e.g., dialysis, vacuum stripping and steam distillation.

The cationic, advanced epoxy resins of this invention in the form of aqueous dispersions are useful as coating compositions, especially when applied by electrodeposition. The coating compositions containing the cationic resins of this invention as the sole resinous component could be used but it is preferred to include crosslinking agents in the coating composition, so that the coated films, when cured at elevated temperatures, will be crosslinked and exhibit improved film properties. Materials suitable for use as crosslinking agents are those known to react with hydroxyl groups or amino protons; and include blocked polyisocyanates; amine-aldehyde resins such as melamine-formaldehyde, urea-formaldehyde, benzogucinine- formaledyde, and their alkylated analogs; polyester resins, and phenol-aldehyde resins. Preferred crosslinking agents are the blocked polyisocyanates which, at elevated temperatures, deblock and form isocyanate groups which react with the hydroxyl groups of the resin to crosslink the coating. Such crosslinkers are σrepared by reaction ofthe polyisocyanate with a monofunctional active-hydrogen compound. Examples of polyisocyanates and isocyanate- functional prepolymers derived from polyisocyanates and polyois using excess isocyanate groups suitable for preparation of the crossiinking agent are described in US Patent 3,959, 106 to Bosso, etal., ιn Column 15, lines 1-57.

The blocked polyisocyanate crosslinking agents are incorporated into the coating composition at levels corresponding to from 0.2 to 2.0 blocked isocyanate groups per hyoroxyl group of the cationic resin. The preferred level is from 0.5 to 1.0 blocked isocyanate group per resin hydroxyl group. A catalyst optionally may be included in the coating composition to provide faster or more complete curing of the coating. Preferable catalysts for the various classes of crosslinking agents are known to those skilled in the art. For the coating compositions using the blocked polyisocyanates as crosslinking agents, preferable catalysts include dibutyl tin dilaurate, dibutyl tin diacetate, dibutyl ti n oxide, stannous oαanoate, and other urethane- forming catalysts known in the art. Preferably the catalyst is used in amounts from 0.1 to 3 weight percent of binder solids. Unpigmented coating compositions are prepared by blending the cationic resinous product with the crosslinking agent and optionally any additives such as catalysts, solvents, surfaαants, flow modifiers, and defoamers. This mixture is then dispersed in water by any of the known methods. The solids content of the aqueous dispersion is usually from 5 to 30 percent by weight, and preferably from 10 to 25 percent by weight for application by eleαrodeposition.

Pigmented coating compositions are prepared by adding a concentrated dispersion of pigments and extenders to the unpigmented coating compositions. This pigment dispersion is prepared by grinding the pigments together with a suitable pigment grinding vehicle in a suitable mill as known in the art. Pigments and extenders known in the art are useful in these coatings, and include pigments which increase the corrosion resistance of the coatings. Examples of useful pigments or extenders include titanium dioxide, talc, clay, lead oxide, lead silicates, lead chromates, carbon black, strontium chromate, and barium sulfate.

The pH and/or conductivity of the coating compositions may be adjusted to desired levels by the addition of compatible acids, bases, and/or electrolytes known in the art. Other additives such as solvents, surfaαants, defoamers, anti-oxidants, baαericides, etc. may also be added to modify or optimize properties of the compositions or the coating in accordance with practices known to those skilled in the art.

The coating compositions of the invention may be applied by cathodic eleαrodeposition, wherein the article to be coated is immersed in the coating composition as the cathode, with a suitable anode in contaα with the coating composition. When sufficient voltage is applied, a film of the coating deposits on the cathode and adheres to the article to be coated. Voltage applied is preferably from 10 to 1 ,000 volts, more preferably from 50 to 500 volts. The film thickness achieved increases with increasing voltage. Thicker films are achieved by incorporation of the diglycidyl ether of poiyputyiene giycol into the Dackbone of the cationic resins of the invention. Control over the final thickness may be excercised by adjusting the amount of that component used The voltage is applied for between a few seconds to several minutes, preferably from two minutes over which time the current usually decreases as a resistive film is deposited. Any electrically conductive substrate may be coated in this fashion, especially metals such as steel and aluminium. Other aspects of the electrodeposition process are conventional. After deposition, the article is removed from the bath and rinsed with water to remove that coating composition which does not adhere. The uncured coating on the article is cured by heating at elevated temperatures, preferably ranging from 100° to 200°C, for periods of preferably from 1 to 60 minutes.

In another embodiment the flexibilized advanced epoxy resins may be flaked or ground according to known processes and combined with epoxy curing agents and exposed to conditions such that continuous films are formed, without conversion to cationic species. Processes for preparing such powder coatings are generally well known to those skilled in the art.

In another embodiment the flexibilized advanced epoxy resins of this invention can be used in solvent coatings. In such an embodiment the flexibilized advanced epoxy resins and a curing agent can be dissolved in a solvent and such mixture can be coated onto a substrate and exposed to curing conditions. Preferred solvents are alkyl substituted benzenes, ketones, lower alkanols, glycol ethers, chlorinated alkanes, and dimethyl formamide. The preferred sol ids level is from 25 to 80 % by weight; and preferably from 30 to 60 % by weight. Generally curing conditions comprise exposing the coated substituted to temperatures from 20 to 250°C under conditions such that the solvents can be removed from the coating.

The flexibilized advanced epoxy resins of this invention are cured with known curing agents for epoxy resins. In preparing coatings the flexiblized epoxy resin compositions are contacted with curing agents and the mixture is applied in a known manner to a substrate such that the flexibilized advanced epoxy resins are cured to form coatings. Curing agents useful in this invention are those compounds known to the skilled artisan to react with polyepoxides or advanced epoxy resins to form hardened final products and which function to cure the epoxy resin.

The polyhydroxy compounds described hereinbefore wherein the hydroxy moieties are bound to aromatic moieties are among suitable curing agents. The novolac based compounds and the bisphenolic compounds are the preferred polyhydroxy compounds for use as curing agents. Examples of other preferable curing agents include the oolybasic acids and their anhydrides; othertypes of acids containing sulfur, nitrogen, onospnorus or halogens; soluble adducts of amines and polyepoxides and their salts, such as described in US 2,651 ,589 and US 2,640,037; acetone soluble reaction products of polyamines and monoepoxides; the acetone soluble reaction products of poiyamines with unsaturated nitriies; imidazolme compounds obtained by reaαmg monocarboyxlic acids with polyamines, sulfur and/or phosphorus-containing polyamines obtained by reaαmg a mercaptan or phosphine containing aαive hydrogen with an epoxide halide to form a halohydπn, dehydrochloπnating and then reacting the resulting produα with a polyamine, soluble reaction product of polyamines with acrylate, and many other types of reaαion products of the amines, boron tπfluoπde and complexes of boron tπfluoπde with amines, ethers, phenols and the like, Fπedel-Crafts metal salts, such as aluminum chloride, zinc chloride, and other salts, such as zinc fluorborate, magnesium perchlorate and zinc fluosilicate, inorganic acids such as phosphoric acid and partial esters thereof including n-butyl orthothiophosphate, diethyl orthophosphate and hexaethyltetraphosphate, polyamides containing active ammo and/or carboxyl groups, and preferably those containing a plurality of ammo hydrogen atoms, especially preferred polyamides are those derived from the aliphatic polyamides containing no more than 12 carbon atoms and polymeric fatty acids obtained by dimeπziπg and/or tπmeπzing ethylenically uπsaturated fatty acids containing up to 25 carbon atoms, and melamine reaction products containing methylol substituents

Preferred classes of curing agents are the polyamines and amides Such preferred curing agents include aliphatic polyamines, polyglycoldiamines, polyoxypropylene diamines, polyoxypropylenetπamines, amidoamines, imidazolines, reaαive polyamides, ketimines, araliphatic polyamines (i e xylylenediamine), cycloaliphatic amines (i e isphoronediamine or diaminocyclohexane) menthane diamine, 3,3-dιmethyl-4,4-dιamιno-dιcyclohexylmethane, heterocyclic amines (aminoethyl piperazine), aromatic polyamines, (methylene diani ne), diamino diphenyl sulfone, mannich base, phenalkamine, N,N'N"-tπs(6-amιnohexyl) melamine, and the like Most preferred are cyanamide, dicyandiamide, and its derivatives, diaminodiphenyl sulphone and methylene dianiline

The flexibilized advanced epoxy resin compositions of this invention are contaαed with sufficient curing agents to cure the resin Preferably the ratio of epoxy (glycidyl ether) equivalents to equivalents of curing agent is from 0 5 1 to 2 1 , more preferably from 0 6 1 4to 1 4 0 6; even more preferably from 0 8 1 2 to 1 2 0 8 and most preferably from 0 9 1 1 to 1 1 0 9

The coatings of this invention demonstrate excellent adhesion resistance to cathodic disoondment excellent flexibility and impact resistance, good compatibility with a wide variety of resinous ^pinders sucn as acrylics, aikyds, polyesters as well as curing agents like polyamines, melamine or onenol resins The following examples are included for illustrative purposes only and do not limit the scope of the claims. Unless otherwise stated all parts and percentages are by weight.

EXAMPLE 1 - Reaction of polypropylene glycol diglycidyl ether, bisphenol A and diglycidyl ether of bisphenol A.

Not an example of the invention.

To a to a 51 glass reactor are charged 1550.4 g of a diglycidyl ether of bisphenol A having an EEW of 187.0 (8.33 epoxy eq), 618.0 g of a diglycidyl ether of polypropylene glycol (EEW of 334.0) prepared from a polypropylene glycol having a molecular weight of 425 (1.85 epoxy equivalents) and 831.6 g of bisphenol A (7.29 eq of phenolic hydroxyl). The mixture is heated to 100°C and 2.9 g of alkyl triphenyl phosphonium catalyst is added. The reactor is slowly heated to 140°C. At 140°C the reaction mixture exotherms and the temperature rises to 160°C. The temperature is maintained at 160°C for 60 minutes at which time a sample of the reaction mixture istaken which demonstrates an EEW of greater than 1000. The reaction is quenched by cooling. The resulting resin is crushed and stored. The final epoxy equivalent weight is 1059.

The solid resin is converted into a water-dispersed form usable for the formulation of cathodic eleαrodeposition primers by following procedure. In a reactor 620 g of

^•* the solid resin is dissolved in a mixture of 34 4 g xylene and 34 4 g Dowanol* PPh glycol ether, the phenyl ether of propylene glycol at a temperature of 1 10°C.467.4 g of a 70 wt % solution of blocked polymeric methylene diisocyanate crosslinker in methyl isobutyl ketone is blended with the resin solution. Then 40 7 g of a 73 wt % solution in methyl isobutyl ketone of the diketimine of methylisobutylketone and diethylenetπamine is added, followed by 33.1 g of ^u methylethanolamine. The reaαor is cooled to keep the reaction temperature from rising over 1 10°C. A temperature of 110°C is maintained for 60 minutes Then 38 3 g of Dowanol* PPh glycol ether is added to the reactor A second reactor is now prepared containing a mixture of a 1306 g of deionized water, 39.3 g of lactic acid (0.31 eq. of acid) as well as 17.2 g of a mixture of suitable cationic surfactant and defoamer Under strong stirring the hot resin mixture is slowly

' -' poured into the second reaαor, whereby a low viscosity dispersion is obtained The dispersion is diluted further by the addition of 637 0 g of deionized water. The dispersion is heated to 65°C, after which the volatile organic solvents are stripped off over 2 hours by distillation at a reduced pressure of 250 mbar. The solids content of the dispersion, after 1 hour drying at 150°C, is determined to be 36 40 % The dispersion is mixed with a commercially available

^^u pigment paste and diluted by addition of deionized water so that the final pigmented dispersion has a 0 3 : 1 ratio of pigment to binder at a solids content of 20 wt %

EXAMPLE 2 - Reaαion of diglycidyl ether of polypropylene glycol with bisphenol A and subsequent reaαion of the product with diglycidyl ether of bisphenol A Not an Example of the Invention

To a reactor similar to the one described in Example 1 is charged 618 1 g of the diglycidyl ether of polypropylene glycol described in Example 1 and 831 6 g of bisphenol A (7 24 eq of phenolic hydroxyl) The mixture is heated to 100°C and 2 9 g of ^^υ alkyltriphenylphosphonium catalyst is added The reaαor is slowly heated to 150°C (1 to 2°C per minute). At 150°C an exotherm begins and the reaction temperature increases to 160°C The temoerature is maintained at 160°C until the weight percentage of eooxy in the mixture is ess than 0 1 parts by weight, about 60 minutes To the reaction mixture is added 1550 4 g of the diglycidyl ether of bisphenol A described in Example 1 (8.33 epoxy equivalents) The

35

* Trademark of The Dow Chemical Company temperature drops to 110°C as a result of this addition. The mixture is mixed for 5 minutes and then the temperature is slowly raised by heating (1 to 2°C per minute). At 140°C an exotherm begins and the temperature rises to 170°C. The temperature is reduced with cooling to 160°C at which temperature the reaction mixture is maintained until a sample removed shows the resin has an epoxy equivalent weight of more than 1000. The reaction is quenched by cooling, and the resulting solid resin has an EEW of 1099. An aqueous dispersion is prepared as described in Example 1 , the amount of amine added is 95 % of the epoxy equivalents, and the amount of ⁰ lactic acid is adjusted to reach the same neutralization level.

EXAMPLE 3 - Reaction of diglycidyl ether of polypropylene glycol with bisphenol A and subsequent reaction of the product with diglycidyl ether of bisphenol A

Not an Example of the Invention. 5

Example 2 is repeated using 620.0 g of the diglycidyl ether of polypropylene glycol (EEW 317.7) prepared from a polypropylene glycol of MW 390, 571.0 g of bisphenol A and 2.9 g of alkyltriphenylphosphonium catalyst. The mixture is heated to 100°C. The reactor is then slowly heated to 150°C (1 to 2°C per minute).Tothe reaction mixture is added 1543.8 g of ^ the diglycidyl ether of bisphenol A described in Example 1 (8.33 epoxy equivalents). The temperature drops to 110°C as a result of this addition. The mixture is mixed for 5 minutes and then the temperature is slowly raised by heating (1 to 2°C per minute). At 140°C an exotherm begins and the temperature rises to 170°C. The temperature is reduced with cooling to 160°C at which temperature the reaction mixture is maintained until a sample removed shows the resin ⁵ has an epoxy equivalent weight of more than 1000. The reaction is quenched by cooling, and the resulting solid resin is crushed and stored. The EEW is 1082. An aqueous dispersion is prepared as described in Examples 1 and 2.

EXAMPLE 4 - Reaction of diglycidyl ether of polybutylene glycol and bisphenol A and ^ subsequent reaction with the diglycidyl ether of bisphenol A

Example 3 is repeated with 412.2 g of a diglycidyl ether of a polybutylene glycol

(EEW 250.0), wherein the polybutylene glycol MW (number average) is 300; 583.8 g of bisphenol A, and 2.0 g of catalyst as described in Example 1. it takes about 90 minuxtes until the weight percentage of epoxy in the mixture is less than 0.1. To the reactor is added 1004.9 g of 5 the liquid epoxy resin described in Example 1. The resulting solid resin has ane EEW of 1090. A water dispersion is prepared as described in Examples 1 and 2.

EXAMPLE 5- Reaαion of diglycidyl ether of polybutylene glycol and bisphenol A and subsequent reaαion with dig ycidyl bisphenol A

Example 3 is repeated with 412.2 g of a diglycidyl ether of a polybutylene glycol (EEW 367.0), wherein the MW (number average) of the polybutylene glycol precursor is 550; 546.5 g of bisphenol A, and 2.0 g of catalyst as described in Example 1. It takes about 60 minutes until the weight percentage of epoxy in the mixture is less than 0.1. To the reaαor is added 1042.2 g of the liquid epoxy resin described in Example 1. The EEW of the resulting resin is 1087. An aqueous dispersion is prepared as described in Examples 1 and 2.

The dispersions of Examples 1 to 5 are tested for pH and conductivity. The results are compiled in Table I.

Table I

ot an examp e o t e invention ** Microsiemens / centimeter

EXAMPLES 2 to 5 - Cathodic Deposition of Coatings and Testing of Properties Dispersions prepared in Examples 2 to 5 are separately deposited on Bonder 26 phosphatized steel panels by electrodeposition, rinsed in deionized water and baked at 175°C or 20 minutes. Deposition conditions are chosen such that the coating has a thickness of 25 microns. The Erichsen Indentation test is performed to a "first crack" endooint. The Salt Bath corrosion test conditions are 500 hours of immersion in a 5 percent soαium chloride in water solution at 55°C The results are compiled in Table !l. Table II

10

EXAMPLE 6 - Reaαion of Diglycidyl ether of Bisphenol A, diclycidyl ether of polypropylene glycol, and

Bisphenol A

Not an example ofthe invention

The following amounts of raw materials are charged into a 1 liter glass reactor: 382.7 g D.E.R.* 331 epoxy resin (EEW = .186.9), 200 g of D.E.R.* 732 epoxy resin, the diglycidyl ether of a polypropylene glycol, (EEW= 318.5) and 217.3 g of Bisphenol A. The mixture is heated under stirring and a nitrogen purge to 90°C and then 0.71 g of a trialkyl phosphonium catalyst is added. The temperature is gradually increased. At 140°C the exotherm begins and the temperature increases to 180°C. The temperature is then decreased with cooling to 170°C and maintained for 45 minutes, until a sample of the reactor contents shows an EEW of 1050. „ The resin is cooled, crushed and stored.

The resulting resin is converted into an aqueous dispersion using the procedure described in Example 1 , with the exceptions that the crosslinker is as described in US Patent 4,104,147, more particularly 70 wt % solution in MIBK of an 3: 1 :3 adduct (based on molar .... quantities) of toluenediisocyanate, tπmethylolpropane and ethylhexanol. Additionally, 10 g of dibutyltindilaurate curing catalyst is added to the resin crosslinker blend, just before dispersing it into water.

After stripping, the dispersion is diluted to 20 wt % solids and used for ,_ eieαrodepositing an unpigmented coating unto Bonder 26 panels and unto degreased untreated steel panels. The coatings are cured for 20 minutes at 190°C. Deposition conditions are cnosen in such a way that the final film thickness of the cured films is 20 urn. EXAMPLE 7 - Reaαion of Bisphenol A with diglycidyl ether of polypropylene glycol, and subsequent reaαion with Bisphenol A diglycidyl ether Not an example of the invention

The following amounts of raw materials are charged into a 11 glass reactor. 200 g of D E R * 732 epoxy resin, the diglycidylether of polypropyleneglycol, (EEW = 318 5) and 217 3 g of bisphenol A The mixture is heated under stirring and nitrogen purging to 90°C after which

10 0 71 g of a tri alkyl phosphonium catalyst is added The reaction mixture is gradually heated to 170°C, and maintained for 50 minutes until analysis of a sample of the reaαion mixture shows an epoxy content less than 0 1 wt % 387 2 g of D E R * 331 epoxy resin (EEW = 186 9) are added, causing a temperature drop to 1 10°C, after which the mixture is reheated to 130°C The exothermic effeα of the continuing reaαion raises the temperature to 170°C The reaαion is ^b continued at that temperature for 20 minutes until analysis of the resin gives an EEW value of 1072 The resin is cooled, crushed and stored

The conversion into an aqueous dispersion, the electrodeposition of the resulting clear coating and its curing are performed in the same way as described in Example 6 0

EXAMPLE 8 - Reaction of diglycidyl ether of Bisphenol A diglycidyl ether of polypropylene glycol and Bisphenol A

Not an example of the invention

Using the procedure as described in Example 5 a resin is prepared The reactor is ⁵ charged with 389 2 g of D E R * 331 epoxy resin, 200 O g of the diglycidylether of a polybutylene glycol (EEW = 368 12) and 210 8 g of bisphenol A The resulting resin has an EEW of 1050

Conversion into an aqueous dispersion, electrodeposition and curing are 0 pe^r ormed in the same manner as described in Example 6, except for the amount of neutralizing acid, which is 5 % higher

EXAMPLE 9 - Reaαioπ of Bisphenol A with diglycidyl ether of polybutylene glycol and suosequent reaαion with diglycidyl ether of Bisphenol A 5 Using the procedure described in Example 6, 200 g of the diglycidylether of a polybutyleπeglycol (EEW= 368.1) and 210.8 g of bisphenol A are charged into the reactor and the reaction proceeds. In the later stage of the reaction 389.2 g of D.E.R.* 331 epoxy resin is added. The resulting resin has an EEW of 1054. Conversion into an aqueous dispersion, electrodeposition and curing are performed in the same way as described in Example 6, except for the amount of neutralizing acid which is 5 % higher.

10 Results of pH and conductivities of the clear dispersions of Examples 6-9 at 20 wt

% solids are listed in Table III. Results of reverse impact, Erichsen Indentation, Salt Bath immersion test and salt spray are also listed. The salt spray test is performed according to ASTM

B 117 for 300 hours on degreased untreated steel panels coated with the cured panels. Tests performed on the cured clear coatings are shown in Table IV.

15 Table III

20

wot an examp e o t e invention

* * I . ..icrosiemens/centimeter

Table IV

Not an example o t e invention EXAMPLE 10 - Reaαion of diglycidyl ether of polybutylene glycol with bisphenol A and subsequent reaαion of the produα with diglycidyl ether of bisphenol A and additional

⁵ bisphenol A.

325 g (0.897 epoxy eq) of the diglycidyl ether of a 550 Mw polybutylene glycol and 408.5 g of bispenol A (3.583 eq of phenolic OH) are charged to a 5 liter reaαor. A gentle nitrogen purge is started over the contents and the temperature is raised at a rate between 1 and 2 degrees C per minute while contents are stirred When the reactor temperature reaches

¹^ 120°C, 1 1 g of alkyltnphenyl phosphonium catalyst are added. Heating of the reactor is continued until a mild exotherm is observed to begin at around 150°C, at which time the external heating is discontinued. Once the exotherm finishes and the temperature returns again to 160°C, 3,240 1 g of a diglycidyl ether of bisphenol A having an EEW of 178 and an additional 1026.4 grams of bisphenol A are charged to the reaαor The temperature is again

' raised at a rate of between 1 and 2 degrees C per minute. At 100°C, and an additional 2.4 grams of alkyltriphenyl phosphonium catalyst are added. Heating is continued until the beginning of an exotherm is observed At this point the external heating is again discontinued.

After exotherm cool-down, and flaking, the epoxy is analyzed and found to have an EEW of

759.7, a Metier softening point of 89 4°C, and a melt viscosity of 1.81 Pa.s at 150 C 0

EXAMPLE 1 1 - Preparation, application and testing of a powder coating

840 4 grams of the flaked resin of EXAMPLE 10, 259.6 grams of D.E.H. 81 (commercially available phenolic OH functional hardener commonly used in pipe and funαional powder coatings), 600 grams of Ti0₂, 200 grams of BaSOd, and 100 grams of CaC0₃ are premixed mechanically in a lab mixer for 3 minutes at 600 RPM. This dry mix is then completely melt- homogenized by feeding it through a ZSK 30 twin screw laboratory extruder at a temperature of 90°C and a screw speed of 300 RPM. The extrudate is cooled by passing it between two water cooled rolls and the resulting sheet is then flaked. The flakes are ground on a lab grinder until 100% will pass through a 100 micron screen This final powder is bagged ⁰ and kept cool and dry.

6 mm thick cold rolled steel panels are cut to nominal dimensions of 150 by 70 mm. The finished test panels are degreased with acetone, glass blasted to an average profile of 10 microns, and promptly placed in a circulating air oven wnich has been set to 235°C. After preheating for 20 minutes, the panels are removed from the oven and hung in a spray booth. The panels are eleαrostatically sprayed to an estimated thickness of 350 microns with the Dowαer coating. After coating the panels are returned to the 235 degree oven for a 1 minute post cure, after which they are quenched by immersion in cold water. The resulting coatings are hard and glossy.

The flexibility of the coating istested by bending the coated panels around an 18 mm diameter mandrel in accordance with DIN 35571 flexibility test. 10 panels prepared as described and at an average coating thickness of 347 microns are found to tolerate a 36.5 degree flex before cracking. This is considered to be excellent flexibility.

10

EXAMPLE 12 - Reaction of digiycidyl ether of polybutylene glycol with bisphenol A and subsequent reaction ofthe product with diglycidyl ether of bisphenol A.

404.1 grams (1.609 epoxy eq) of the diglycdyl ether of the 330 Mw polybutylene glycol and 494.6 grams of bisphenol A (4.338 phenolic OH eq) are charged to a 2 liter reactor. A

^{1 5} gentle nitrogen purge is started overthe contents and the temperature is raised at a rate between 1 and 2 degrees C per minute while contents are stirred. When the reactor temperature reaches 120°C, 1 gram of alkyltriphenyl phosphonium catalyst is added. Heating of the reactor is continued until a mild exotherm is observed to begin at around 150°C, at which time the external heating is discontinued. Once the exotherm finishes and the temperature

²⁰ returns again to 160°C, 601.4 g (3.36 epoxy eq) of diglycidyl ether of bisphenol A with EEW of 178.6 are charged to the reactor. The reactor is again heated at a rate of 1 to 2 degrees per minute until the temperature reaches 120°C at which point an additional 1.65 grams of alkytriphenyl phosphonium catalyst are added. Heating of the reactor is continued until an exotherm is observed at around 150 degrees. At this point the external heating is discontinued

²⁵ until the reactor temperature falls again to 150°C. Reactor is then maintained at 150 until the

EEW is found to exceed 2800. The advanced resin is poured from the reactor into an aluminum foil tray and allowed to cool to room temperature. The Metier Softening Point is determined to be 104.1°C and the solution viscosity at 40 wt % solids in diethylene glycol monobutyl ether is measured to be 1914 cSt. 30

EXAMPLE 13 - Formulation, application, and testing as a can coating

80 grams of the advanced resin of EXAMPLE 12 are dissolved in 150 grams of a solvent blend consisting of 50 parts Dowanol PMA, 10 parts of 2-butanol and 40 parts of Solvesso 100 10 grams (soiids) each of Phenodur PR 285 and Bakelite 100 (commercial phenolic " resole crosslinkers) are added to the advanced resin solution. 1 gram (solid) of phosphoric acid is added to accelerate the cure. The formulation is allowed to age for 24 hours at 40°C and is then reduced with the solvent blend described above until a ASTM D445 viscosity of 250 mPa.s is reached. The solids content is measured to be 38 wt %

The formulation is applied using a wire wrapped draw down rod to a 0.235 mm thick sheets of Ancrolyt tin free steel and Androlyt tm plate (both available from Rasselstein AG) which have been degreased by rinsing with acetone. A wet application of between 20 to 40 microns is chosen such that dry film thickness of 5 to 6 microns is obtained. The coated tin ^ plate panels are placed in a circulating air oven preheated to 200°C for a cure time of 10 minutes. The coated tin free steel panels are cure at 280 for 28 seconds.

To test the performance of the coatings, 2 cm high asymmetric cans with 5, 10, 15, and 20 mm radius corners were drawn from the coated tin free steel and tin plate sheets. In ^ each case, perfect coating integrity on all corners and edges is maintained throughout the drawing process. The drawn cans are further tested by exposing them to water at 129°C. The exposure time is 30 minutes for the tin plate cans and 90 minutes for the tin free steel cans. In each case, the integrity of the coating is maintained during the exposure and no blushing or blistering is observed. 0

Claims (10)

PATENT CLAIMS:

1. Flexibilized epoxy resin comprising the residue of

A. one or more polyglycidyl ethers of a water or di- or trihydroxy substituted Cι_6 hydrocarbon initiated polybutylene glycol;

B. one or more polyaromatichydroxy compounds; and

C. one or more polyglycidyl ethers of polyaromatichydroxy compounds; wherein substantially all of the glycidyl ether moieties of polybutylene glycol are bound to the polyaromatichydroxy compounds through the reaction product of the glycidyl ether moieties with the aromatichydroxy moieties; each polyaromatichydroxy compound is bound to at least one polyglycidyl ether of polybutylene glycol or at least one polyglycidyl ether of polyaromatichydroxy compound through the reaction product of an aromatichydroxy moiety and glycidyl ether moiety; each residue of polyglycidyl ether of polyaromatichydroxy compound is bound to at least one residue of polyaromatichydroxy compound through the reaction product of a glycidyl ether moiety and an aromatichydroxy moiety; wherein the mole ratio of polyaromatichydroxy compound to polyglycidyl ether of polybutylene glycol is two or greater; and sufficient polyglycidyl ether of polyaromatichydroxy compound is present in the resin such that the terminal moieties of the resin are glycidyl ether moieties from the polyglycidyl ethers of polyaromatichydroxy compounds.

2. Flexibilized epoxy resin compositions according to Claim 1 wherein the epoxy resin contains at least 5 percent by weight of polyglycidyl ethers of polybutylene glycol.

3. Flexibilized epoxy resin compositions according to Claim 2 wherein the glycidyl ether of a polybutylene glycol corresponds to the formula: the polyaromatichydroxy compound corresponds to the formula

and the polyglycidyl ether of a polyaromatichydroxy compound corresponds to the formula:

wherein

Ar is independently in each occurrence a nydrocarbon moiety containing one or more aromatic rings, or a hydrocarbon moiety containing one or more aromatic rings and one or more heteroatoms of oxygen, nitrogen, sulfur or halogen; R is independently in each occurrence hydrogen, methyl or ethyl with the proviso that for each

unit either both of R are methyl or one R is ethyl and the other is hydrogen; T is independently in each occurrence a direct bond or the moiety

Z is independently in each occurrence oxygen or

X is independently in each occurrence a C* -alkyl moiety, R¹ is independently in each occurrence hydrogen or a C_LU alkyl moiety, a is inoepenαently in each occurrence a positi e real numoer of about 1 or greater, b is independently in each occurrence 2 or 3; c is independently in each occurrence a positive real number of greater than 1 ;

with the provisio that the hydroxy moieties of the polyaromatichydroxy compounds and the glycidyl ether moieties of the polyglycidyl ethers of polyaromatichydroxy compounds are bound to aromatic rings.

4. Flexibilized epoxy resins according to Claim 3 wherein the resins comprise compounds corresponding to the formula

wherein:

Ar is independently in each occurrence a hydrocarbon moiety containing one or more aromatic rings, or a hydrocarbon moiety containing one or more aromatic rings and one or more heteroatoms of oxygen, nitrogen, sulfur or halogen;

B is

E is independently in each occurrence a moiety according to one of the formulas CH₂TCHCH₂ or

V 0

R is independently in each occurrence hydrogen, methyl or ethyl with the proviso that for each

unit either both of R are methyl or one R is ethyl and the other is hydrogen; T is independently in each occurrence a direct bond or the moiety

R¹ is independently in each occurrence hydrogen or a C-.₄ alkyl moiety;

Z is independently in each occurrence oxygen or 5

X is independently in each occurrence a C-,.6 alkyl moiety; 0 a is independently in each occurrence a positive real number of 1 or greater; b is independently in each occurrence 2 or 3; c is independently in each occurrence a positive real number of greater than 1 ; d is independently in each occurrence a number of from 0 to 2; e is independently in each occurrence 0 or 1. 5

5. Flexibilized advanced epoxy cationic resin comprising the flexibilized advanced epoxy resin according to any one of Claims 1 to 4 which futher comprise

D. cationic terminal moieties comprising the reaαion product of a nucleophile and the glycidyl ether moieties. 0

6. Flexibilized advanced epoxy cationic resin compositions according to Claim 5 wherein the nucleophile is a monobasic heteroaromatic nitrogen compound, tetra(lower alkyl) thiourea, a sulfide corresponding to the formula: ! R6-S-R6 an amine corresponding to the formula: R7-N-R8 ;

R8 or a phosphine corresponding to the formula: R9-P-R9 ;

R9

wherein:

R⁶ is independently in each occurrence lower alkyl, hydroxy lower alkyl or two of R⁶ may combine as one 3 to 5 carbon atom alkylene radical thereby forming a heterocycloalkylene moiety;

R⁷ is independently in each occurrence hydrogen, hydroxyalkyl, lower alkyl, araikyl or aryl;

R8 is independently in each occurrence hydrogen, lower alkyl, hydroxy lower alkyl, the moiety

or two of R⁸ may combine to form an alkylene radical having from 3 to 5 carbon atoms; R9 independently in each occurrence lower alkyl, hydroxy lower alkyl or aryl; ¹° is independently in each occurrence a C_2--*o alkylene group; R^{1 1} is independently in each occurrence lower alkyl .

7. A coating composition which is suitable for electrodeposition comprising an aqueous dispersion ofthe advanced epoxy cationic resin of Claim 6 in combination with a crosslinking agent selected from a blocked polyisocyanate, an amine aldehyde resin, a phenol aldehyde resin and a polyester resin.

8. The use of the advanced epoxy cationic resin of Claim 6 in electrodeposition coating compositions.

9. A process for preparing flexibilized epoxy resins comprising

A. reacting a polyglycidyl ether of a di- or tri- hydroxy G.6 hydrocarbon or water initiated polybutylene glycol with two or more moles of a polyaromatichydroxy compound per mole of polyglycidyl ether of polybutylene glycol under conditions such that substantially all of the glycidyl ether moieties react with aromatichydroxy moieties ofthe polyaromatichydroxy compounds; B. thereafter reaαing the reaαion produα with an excess of one or more polyglycidyl ethers of polyaromatichydroxy compounds, optionally one or more polyaromatichydroxy compounds and, optionally one or more chain terminators under conditions such that the aromatichydroxy moieties of the reaction product, and optionally the polyaromatichydroxy compound, react with the glycidyl ether moieties of the polyglycidyl ethers of polyaromatichydroxy compounds wherein the terminal moieties of the product are glydicyl ether moieties.

10. A process according to Claim 10 wherein the polyglydicyl ether of polybutylene glycol and the polyaromatichydroxy compound are contacted in the presence of a catalyst for the reaction of a hydroxy moiety with a glycidyl ether moiety, the temperature of the mixture is increased until the reaction mixture begins to exotherm and the reaαion mixture is reaαed until substantially all of the glycidyl ether moieties reaα with the aromatichydroxy moieties; thereafter one or more polyglycidyl ethers of an polyaromatichydroxy compound, optionally one or more polyaromatichydroxy compounds, and optionally one or more chain terminators are added, the temperature of the reaαion mixture is raised to a temperature at which the reaαion mixture exotherms and the mixture is reacted until the desired molecular weight is reached.