CA1162669A - Ambient or low-temperature curable coatings - Google Patents

Abstract

Abstract of the Disclosure Ambient or low-temperature curable solutions or aqueous dispersions of (1) a polymer containing units polymerized from a monomer mixture of (a) from about 0.25% to about 30% by weight of a polymerizable aldehyde, and (b) at least one copolymerizable mono-ethylenically unsaturated monomer, with (2) a curing agent selected from the group of dicarboxylic acid bis-hydrazides, dicarboxylic acid bis-hydrazones, and acrylic oligomers and low molecular weight acrylic solution polymers containing a plurality of pendant hydrazide or hydrazone groups. The solutions or dispersions are useful as general industrial coatings, maintenance coatings, furniture and appliance coatings, heavy transportation coatings, automobile refinishes and plastics coatings.

Description

~ ~ 626~9 AMBIENT OR LOW-TEMPERATURE CURABLE COATINGS
.
CROSS-REFERENCE
Thl8 appllcatlon 18 related to the commonly-asslgned appllcatlon o~ B~orn E. Lars~on and Fred A. Declderlo entltled AMBIENT OR LOW-TEMPERATURE CURABLE COATINGS FOR
LEATHER AND OTHER FLEXIBLE SUBSTRATES ~lled on the same date as thls appl~catlon, and glven Canadlan Appllcation No.
344,448.
Fleld of the Invention This inventlon relates to coating compositlons contalnlng a solutlon or aqueous dlsperslon of a polymer o~
polymerlzable aldehydes, 4~ unsaturated aclds, and alkyl esters Or methacryllc acld and acryllc acld and, as a curlng agent therefor , dlcarboxyllc acld bls-hydrazldes and bls-hydrazones, and acryllc ollgomers and low molecular welght acryllc solutlon polymers contalnlng a plurality o~ pendant hydrazlde or hydrazone groups. The compositlons are useful as general lndustrlal coatlngs, malntenance coatlngs, furnlture and appllcance coatlngs, heavy transportatlon coatlngs, automoblle reflnlshes and plastlcs coatlngs.
Descrlptlon of the Prlor Art U.S. Patent 3,513,125 dlscloses the use of varlous hydrazldes to modlfy and/or crossllnk varlous polymers lncludlng ketone and aldehyde polymers. Optlmally, the chosen crossllnklng aBent ln the chosen polymer system ls ¢ompletely non-reactlve at the blendlng temperature and crossllnklng 18 generally performed at 70C to ., ~.
i ~
f ~~~

1 1 626~9 300C. The compositions disclosed have varied uses, for example coatings for wood, metal, and paper; films;
molded items; caulking compositions; adhesives and the like.
U.S. Patent 3,025,265 discloses polymers containing hydrazide or hydra~one functional groups, prepared by the reaction of hydrazine with polymerized units of carboxylic acids, including acrylic acid and methacrylic acid and ester or acid chloride derivatives thereof, which are crosslinkable by reaction with a relatively small molecule containing aldehyde or ketone functional groups. Examples of the crosslinking aldehydes and ketones mentioned are acrolein and polyvinyl methyl ketone. The crosslinking reactions disclosed in the patent can be accelerated by heat.
U.S. Patent 3,455,861 discloses the use of an aqueous dispersion of an acrolein-acrylonitrile~ethyl acrylate terpolymer mixed with crosslinking agents including phenol-, urea-, and melamine-formaldehyde resins and hydrazine to form an elastic coating on leather.
U.S. Patents 4,016,127 and 3,896,085 disclose emulsion polymers containing (a) from about 0.25 to 4%
by weight acrolein, (b) from about 0.5 to 10% by weight of an ethylenically unsaturated carboxylic acid, and (c) up to about 99.25% by weight alkyl acrylate, alkyl methacrylate, and mixtures thereof which are curable with ammonia, polyprimary amines, and hydrazine. The compositions of the patent are useful in treating leather and particularly in base coat leather treating compositions.
- Background of the Invention .

Of the many ambient curable coatings available, those which are considered among the most useful and effective for general industrial coatings are the 1 ~ 626~9 ambient cured aliphatic urethane coatings. However, these coatings are very expensive and are deficient in certain properties, and have not been accepted for broad use in industrial coatings. The aliphatic isocyanate residues in the coatings render them toxic, and they do not provide a durable exterior on metallics, which is a requirement in automobile refinishes. Thus, there is a need for an effective general industrial coating which is not costly, non-toxic and ambient or low-temperature curable.
SUmmarY of the Invention It is an object of the present invention to provide ambient or low-temperature curable polymer coating compositions.
Another object is to provide improved crosslinked coatings carried on a rigid substrate.
A further object is to provide an article of manufacture comprising a rigid substrate coated with the improved crosslinked coating.
These and other objects as will become apparent are achieved by the present invention which comprises an ambient or low-temperature curable polymer composition adapted to coat a rigid substrate comprising:
a. a polymer polymerized from a monomer mixture comprising (1) from about 0.25% to about 35%
by weight of a polymerizable aldehyde, and

(2) the balance to 100% of at least one copolymerizable mono-ethylenically unsaturated monomer selected from the group consisting of Q ,~ -ethylenically unsaturated carboxylic acids, (Cl-C24)alkyl methacrylates, (Cl-C24)alkyl acrylates, vinylidene halides, vinyl halides, (meth)acrylonitrile, vinyl esters, ethylene and alpha-olefins, ocrylic and methacrylic ,~ ' ., ., ., 1 1 ~2~69 acid esters of alcohol-ethers, vinyl ethers, styrene and alkyl-substituted styrenes and vinyl aromatics the combination of monomers being selected to provide a Tg of the polymer of greater than about 0C; and b. a curing agent comprising a member selected from the group consisting of a dicarboxylic acid bis-hydrazide represented by the formula, H2N-NH-C(O)-R-C(0)-NH-NH2, a . dicarboxylic acid bis-hydrazone represented by the formula RlR2C=N-NH-C(O)-R-C(O)-NH-N=CRlR2, and acrylic oligomers and low molecular weight acrylic solution polymers containing a plurality of pendant hydrazide groups of the formula -C(O)-NH-N~2 or hydrazone groups of the formula -C(O)-NH-N=CRl,R2, wherein ~
is a member selected from the group consisting of a divalent alkylene group or alicyclic group having ~rom 0 to 34 carbon atoms and a divalent aromatic ring and Rl and R2 are selected from the group consisting of H and (Cl-C6) alkyl and alicyclic groups, the amount of bis-hydrazide or bis-hydrazone being selected to provide a ratio of hydrazide or of hydrazone groups to aldehyde groups of the polymer in the composition of from about 1:2 to 2:1.
In a preferred embodiment the polymer component of the composition of the invention comprises an aqueous emulsion polymer containing from about 30% to about 60%
by weight resin solids polymerized from a monomer mixture comprising (l) from about 0.5% to about 10% by weight of a polymerizable aldehyde selected from the group consisting of acrolein and methacrolein, (2) from about 0.5% to about 10~ by weight of an ~ ethylenically 1 ~ ~26~9 unsaturated carboxylic acid selected from the group consisting of acrylic acid and methacrylic acid, and (3) up to about 99% by weight of at least one copolymerizable monomer, the combination of monomers being selected to provide a Tg of the polymer of from about +10C to about 60C.
In another preferred embodiment, the polymer component of the composition of the invention comprises an aqueous heteropolymer containing from about 30~ to about 60% by weight resin solids, the particles of which comprise (a) about 50 parts to 85 parts by weight of a first polymer having a Tg of greater than 0C, preferably from about +10C to about 60C formed by emulsion polymerization of a first monomer mixture comprising (1) from about 0.5% to about 10% by weight of a polymerizable aldehyde selected from the group consisting of methacrolein and acrolein, (2) from about 0.5% to about 10% by weight of at least one ~,~ -ethylenically unsaturated carboxylic acid, and (3) up to about 99% by weight of at least one copolymerizable mono-ethylenically unsaturated monomer; and (b) about 15 parts to 50 parts by weight of a second polymer having a Tg of about 60C to about 0C formed by emulsion polymerization, in the presence of the first polymer, of a second monomer mixture comprising at least one copolymerizable mono-ethylenically unsaturated monomer, the sum of the parts in the first monomer mixture and the second monomer mixture always being 100 parts by weight.
In a more preferred embodiment of the invention, the polymer component of the composition of the invention comprises an aqueous emulsion polymer containing from about 30% to about 60% by weight resin solids polymerized from a monomer mixture comprising (1) from about 1% to about 7.5% by weight of acrolein, (2) from about 1~ to about 7% by weight of a member selected from the group consisting of acrylic acid and methacrylic acid, and (3) up to about 98~ by weight of at least one monomer selected from the group consisting of (Cl-C24)alkyl methacrylates and (Cl-C24)alkyl acrylates the S combination of the alkyl methacrylates and alkyl acrylates being selected to provide a Tg of the polymer of from about +10C to about 60C.
The polymerizable aldehyde used in the polymer component of the composition can be a member selected from the group consisting of acrolein methacrolein, vinylbenzaldehyde and crotonaldehyde and mixtures thereof. Acrolein and methacrolein are preferred.
Acrolein is most preferred. A minor amount of the aldehyde component can be replaced with other polymerizable carbonyl compounds such as vinyl acetoacetate, allyl acetoacetate, methyl vinyl ketone, vinylbenzyl methyl ketone, and acetoacetoxyethyl methacrylate Examples of the ~,~ -ethylenically unsaturated acids which can be used in forming the polymers of the invention include acrylic acid, methacrylic acid, ethacrylic acid, itaconic acid, aconitic acid, crotonic acid, citraconic acid, maleic acid, fumaric acid, ~ -chloroacrylic acid, cinnamic acid, mesaconic acid, and mixtures thereof. As indicated above, acrylic acid and methacrylic acid are preferred.
Examples of the (Cl-C24) alkyl groups of the esters of methacrylic acid and acrylic acid which can be used in forming the copolymers used in the invention include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, amyl, isoamyl, t-amyl, hexyl, cyclohexyl, 2-ethylhexyl, octyl, decyl, lauryl, myristyl, cetyl, stearyl groups, and the like. In forming the random polymerized emulsion polymer and the ~rst polyIer o~ the emul~ion hetero~olyIer used in the , ,..
., .

1 ~ 62~69 invention, a combination of butyl acrylate with methyl methacrylate in relative amounts selected to meet the Tg requirements for the polymer is preferred.
While acrylates and methacrylates are preferred, other mono-ethylenically unsaturated polymerizable monomers useful in the invention are vinylidene halides, vinyl halides, (meth)acrylonitrile, vinyl esters such as - vinyl formate, vinyl acetate and vinyl propionate, and mixtures of ethylene and such vinyl esters, alkyl methacrylic esters, acrylic and methacrylic acid esters of alcohol-ethers such as diethylene glycol monoethyl or monobutyl ether, styrene and alkyl substituted styrenes and vinyl aromatics, mixtures of ethylene with other alpha-olefins such as propylene, butylene, pentene, and the like, and combinations of ethylene with vinyl ethers such as methylvinyl ether, ethylvinyl ether, vinyl 2-methoxyethyl ether, vinyl 2-chloroethyl ether and the like.
The polymers of the invention can be prepared by conventional emulsion or solution polymerization techniques. The emulsifiers or dispersing agents employed for preparing the monomer emulsions or polymer emulsions may be of the anionic, cationic or nonionic type. Also a mixture of nonionic type with either anionic or cationic types may be used.
Suitable anionic dispersing agents include for example the higher fatty alcohol sulfates, such as sodium lauryl sulfate, and the like, alkylaryl sulfonates such as sodium or potassium isopropylbenzene sulfonates or isopropyl naphthalene sulfonates, and the like; alkali metal higher alkyl sulfosuccinates, such as, sodium octyl sulfosuccinate, sodium N-methyl,N-palmitoyltaurate, sodium oleyl isothionate and the like, and alkyl metal salts of alkylarylpolyethoxyethanol sulfates or sulfonates, such as sodium ., tert-octylphenoxypolyethoxyethyl sulfate having 1 to 5 oxyethylene units and the like.
Suitable cationic dispersion agents include laurylpyridinium chlorides, cetyldimethyl amine acetate, and alkyldimethylbenzylammonium chlorides in which the alkyl group has from 8 to 18 carbon atoms.
Suitable non-ionic dispersing agents include alkylphenoxypolyethoxyethanols having alkyl groups of from about 7 to about 18 carbon atoms and from about 6 to about 60 oxyethylene units such as heptylphenoxypolyethoxyethanols, methyloctylphenoxypoly-ethoxyethanols, and the like; polyethoxyethanol derivaties of methylene-linked alkyl phenols; sulfur-containing agents such as those made by condensing from about 6 to about 60 moles of ethylene oxide with nonyl mercaptan, dodecyl mercaptan, and the like or with alkylthiophenols wherein the alkyl groups contain from 6 to 16 carbon atoms; ethylene oxide derivatives of long-chained carboxylic acids, such as lauric acid, myristic acid, palmitic acid, oleic acid, and the like, or mixtures of acids such as those found in tall oil containing from 6 to 60 oxyethylene units per molecule;
analagous ethylene oxide condensates of long-chained alcohols such as octyl, decyl, lauryl, or cetyl alcohols, ethylene oxide derivatives of etherified or esterified polyhydroxy compounds having a hydrophobic hydrocarbon chain, such as sorbitan monostearate containing from 6 to 60 oxyethylene units; also, ethylene oxide condensates of long-chain or branched chain amines, such as dodecyl amine, hexadecyl amine, and octadecyl amine, containing from 6 to 60 oxyethylene units; block copolymers of ethylene oxide and propylene oxide comprising a hydrophobic propylene oxide section combined with one or more hydrophilic ethylene oxide sections.
The polymerizable emulsions can be prepared at a temperature in the range of from about 0C to about 100C, but intermediate temperatures are generally preferred. Peroxidic free-radical catalysts and catalytic systems of tbe redox type can be used. A
thermal peroxidic catalyst system is preferred. Redox systems, as is well known, are combinations of oxidizing agents and reducing agents such as a combination of potassium persulfate and sodium metabisulfite. Other suitable peroxidic agents include the "per-salts" such as the alkali metal and ammonium persulfates and perborates, hydrogen peroxide, organic hydroperoxides, such as t-butyl hydroperoxide and cumene hydroperoxide, and esters such as t-butyl perbenzoate. Other reducing agents include water soluble thiosulfates, hydrosulfites, tertiary amines, such as triethanolamine and the like, and salts of metals such as the sulfate salts of metals capable of existing in more than one valent state such as cobalt, iron, nickel, and copper.
The most convenient process of preparing the dispersions of polymers comprises agitating an aqueous suspension or emulsion of the mixture of copolymerizable monomers and redox catalytic combination at room temperature without the application of external heat.
The amount of catalyst can vary but the usual range is from 0.01 to 3% of the peroxidic and the same or lower proportions of the reducing agent based on the weight of the monomer. In this way, it is possible to prepare dispersions which contain as little as 1% and as much as 60% or even more of the resinous polymers on a weight basis. It is more practical and preferred to produce dispersions which contain from about 30% to about 50%
resin solids.
If desired, a chain-transfer agent can be used to moderate the molecular weight of the polymer obtained by the emulsion polymerization procedure in proportion to 1 ~ 62669 the amount of chain-transfer agents used. Ex~mples of useful chain-transfer agents are any one of the following: long-chaln alkyl mercaptans such as t-dodecyl mercaptan, alcohols ~uch a6 i~opropanol, isobutanol, lauryl alcohol, or t-octyl alcohol, carbon tetrachloride, tetrachloroethylene and trichlorobromoethane. Generally from about 0 to about 3% by weigbt, based on the weight of monomer mi~ture, of the chain-transfer agent can be used.
The foregoing aspects of emulsion polymerization to provide ~ldehyde-functional emulsion poly~ers are well known ~s described ln ~.5. Patents 4,016,127 ~nd

3,896,08S.

As Dentioned bereinabove, a preferred emulsion polyDer u~ed in t~e invention co~prises a two-stage beteropolymer. The combination of monomers which constitute the first and ~econd monomer mi~tures used to form the first polymer and the ~econd polymer, respectively, are selected to provide a product heteropolymer having the glass transition temperature (Tg) characteristics of a random copolymer ha~ing a Tg of greater than about 0C, preferably from about +10-C to about 60-C. The monomers of the first monomer mixture forming the first polymer polymer may be the same as the monomers of the second mono~er mixture forming the second polymer or may be different, provided the Tg of the first polymer is greater than 0C, preferably from about +10C to about 60C, and the Tg of the second polymer iJ about 60C to about 0C. The Tg of the first polymer appears to be more critical than that of the second poly~er in order to obtain a product heteropolymer having the Tg characteristics of a random copolymer having a Tg greater than about 0C, preferably about +10C to about 60C.

. ~

I ~ 62~69 The Tg of the first polymer composition and second polymer composition are determinable in a known manner either experimentally or by calculation. The method of calculating the Tg based upon the Tg of homopolymers of individual monomers is described by Fox, Bull. Am.
Physics. Soc. 1, 3, p. 123 (1956).
Monomers may be selected to obtain the appropriate Tg through use of the "Rohm and Haas Acrylic Glass Temperature Analyzern, publication CM-24L/cb of Rohm and ~aas Company, Philadelphia, PA.
The heteropolymer compositions are prepared by emulsion polymerization techniques based upon a 2-stage polymerization and gradual addition of the monomer emulsions in each of the two stages. While it is advantageous to initiate and catalyze the reaction in each stage in a conventional manner, wherein the initiator is activated either thermally or by a redox reaction, thermal initiation is preferred from the standpoint of better storage stability of the resulting polymer emulsion and balance of the resulting cured coating for rigid substrates. The latex particle size should be relatively small, of the order of about 300 nm or less, preferably about 100-200 nm. As is well known, given the same polymer backbone, particle size is controlled primarily by the type and level of emulsifier used in each stage of the emulsion polymerization.
Molecular weight of the heteropolymers generally is of the order of about 70,000 to 2,000,000 preferably about 250,000 to 1,000,000.
The foregoing and other aspects of two-stage heteropolymer emulsion polymerization are well-known as described, for example, in U.S. Patents 3,812,205;
3,895,082~ 3,461,188; 3,457,209 and 3,251,904 except for the critical monomer selection described herein.
Heteropolymer compositions which are useful in the i 1 62~69 inventlon may also be prepared accordlng to methods de~crlbed ln commonly assigned U.S. Patent 4,150,005.

The curing, or crosslinking, ~gent used in the invention is a member selected from the group of dicarboxyl~c acid bis-hydrazides represented by the for~ula, 82N-N~-C(O)-~-C(O)-N~-N~2, dicarboxylic acid _I_-hydrazones r~presented by the formula, R R2C~N-~B-C(0)-R-C(0)-N~-N~CR R , and acrylic oligomers and low ~olecular weight ~crylic solution polyoer6 cont~$ning a plur~lity of pendant hydrazidc group~ of the formula -C(0)-~B-NH2 or hydrazone groups .' of the for~ula -ClO)-~X-N-CRlR2~ ~herein R is ~
eiber ~elected fro~ the group consi~ting of a divalent alkylene group or alicyclic group having from 0 to 34 carbon atoms ~nd a divalent aromatic ring and R and R2 are ~elected from the group consisting of H and (Cl-C6) alkyl and alicyclic groups. The preferred curinq agents f~r use with aqueous emulsion polymers and heteropolymers are the bis-hydrazide compounds and hydrazone derivatives thereof. ~xamples include oxalic bis-hydrazide ~R ~ a covalent bond), adipic bis-hydrazide (R~C4~8), azelaic bis-hydrazide (R~C7~14), dimer acid bis-hydrazide wherein R ~ C34~62, terepbthalic acid bis-hydrazide and isophthalic acid bis-hydrazide, cyclohexane dicarboxylic acid bis-hydrazide, polyethylene oxide bis-acethydrazide, a compound of the formula - ~2N-N~-C(0) ~ -X- O -C(0)-NB-N~2 wherein ., . ~ .
-- X is -o-, -S-, -s(oj2-~ or -C(0)- and the rings are alicyclic or aromatic and hydrazide-functional polymers, and hydrazone water-soluble derivatives thereof. The preferred curing .

agents ror use wlth solutlon polymers contalnlng aldehyde f unctlonallty are the acryllc ollgomers (that 1B~ ollgomers of ester of acryllc acid and methacryllc acld) and low molecular welght acryllc solutlon polymers contalnlng a plurallty Or pendant hydrazlde or hydrazone groups and the dlcarboxyllc acld bis-hydrazones descrlbed above.
The terms "bls-hydrazlde" and dlhydrazlde" are used synonymously.
The hydrazlde and hydrazone curlng agents can be prepared by known processes such as by hydrazlnolysls of carboxyllc ester groups Or the precursor dlcarboxyllc acld or ester group-contalnlng ollgomer. Thls and other hydrazlnolysls reactlons are descrlbed ln "The Chemlstry Or Hydrazldes," H. Paulsen and D. Stoye, Chapter 10, pp. 515-600 ln "The Chemlstry of Amldes", H. Zablcky~ Ed., Intersclence Publlshers, New York, New York, 1970.
A preferred ollgomer ls a homopolymer or copolymer Or one or more alkyl esters Or acryllc acld havlng a number average molecular welght (Mn) of 1000-5000, the nature and preparatlon of which 18 dlsclosed ln U.S. Patent 4,158,736.
(cf. New Zealand Patent 170,274 granted February 3, 1976; and French Patent 2,178,850 These patents are ln the hands of the same asslgnee as the present appllcatlon.
Another prererred oligomer 18 a homopolymer or copolymer o~ one or more alkyl esters of methacryllc acld havlng a number average molecular welght (Mn) of 1000-5000, sultable examples of whlch are descrlbed ln .. .

., 1 ~ 62669 tJ.S. Patents 4,103,093, July 25, 1978;

4~056,559, Nove~ber 1, 19777 4,064,616, November 22, 1971; ~nd 4,133,193! January 9, 1979. (Cf. ~ritish Patent 1,393,273 granted September 3, 1975). These patents are in the hands of the same a~signee as the pre~ent application.
The prefe~red ~crylic solution polymers for use in prepar$ng hydr~zide- or byd~a~one-functional acrylic ~olution polymer3 have a number average ~olecular weight (~w) in the range of 1000-5000 and are prepared from Cl-C~ alkyl acrylates or ~ethacrylates, ~ith or ~ithout comonomers(s) other than the esters of acrylic or ethacrylic ~cid including, for exa~ple, ~tyrene, vinyltoluene, and ethylene, by using a high level of free radical initiatc-r ~n conjunction with conventional ch~in regulating agents such zs mercaptans, methylene chloride, bromotrichloromethane, and the like. The degree of hydrazide functionality obtained by the hydrazinolysis of the ~bove-described acrylic oligomers and low molecular weight solution polymers is generally less than that c~lculated due to loss of some of the hydrazine charged during the hydrazinolysis reaction. A preferred range of degree of hydrazide functionality for solvent-based coatings is from about 2-5 hydrazide groups or hydrazone groups obtained by suitable further reaction of the hydrazide groups, per oligomer or low molecular weight polymer chain.
As illustrated below, the curing, i.e., crosslinking, of the aldehyde-functional polymers by the hydrazide-functional compound involves the formation of a hydrazone moiety:

i ,. ~
- ' , ., .

., ~ C(O)H + -C(o)-NH-NH2 3 -C~O)-NH-N=C(~ H20 pendant hydrazide group product hydrazone aldehyde moiety group As illustrated below, the curing, i.e. crosslinking, of the aldehyde-functional polymers by the hydrazone-functional compound involves an interchange between the aldehyde group and the "blocking" carbonyl group of the hydrazone compound:
~C(O)H + -C(O)-NH-N-CRlR2 ~ -C(O)-NH-N=C(H)~ + RlR2C(O) pendant- hydrazone group product hydrazone aldehyde group moiety Both crosslinking reactions illustrated above are equilibrium processes which are driven to completion in cast films by evaporation of the volatile by-product, either water or the carbonyl compound initially reacted with the hydrazide group to form the starting hydrazone curing agent.
~ he hydrazide or hydrazone curing agent, when it is a water-soluble solid, can be dissolved in water and the resulting aqueous solution can be blended with the disper3ion of the aqueous emulsion aldehyde-containing polymer. When the curing agent is a water-insoluble solid, it can be blended with the dispersion af the aqueous emulsion polymer in the form of ~neat" finely divided solid particles or in the form of a wettable powder wherein the curing agent is admixed with a finely divided solid such as clays, silicates, and carbonates.
Alternatively, the solid particles or wettable powders of the curing agent can be pre-dispersed in water and the resulting dispersion can be blended with the aqueous emulsion powder. When the curing agent is a liquid, it can be blended ~neat~ with the dispersion of the aqueous emulsion polymer, or it can be dissolved in any suitable organic solvent and blended with the aldehyde-containing solution polymer used in the invention. Well-known adjuvants such as alcohols, ether-alcohols, and amides can be added, optionalLy, to the hydrazide or hydrazone ,; ~

... . .
;:, :, ., 7 ~ 62B69 solutions.
The rate of the crosslinking reaction between the aldehyde-functional polymer and the curing agent or, from a more practical standpoint, the potlife of such a system, depends, in part, on the type and level of aldehyde-containing monomer as well as on the backbone composition of, and on the nature (whether aqueous emulsion or solution) of the aldehyde-functional polymer. Acrolein-based polymers, for example, are more reactive than their methacrolein-based analogs apparently as a result of steric hindrance. This steric effect is enhanced by copolymeri~ing either of acrolein or methacrolein with bulky monomers such as butyl acrylate, butyl methacrylate, or styrene substituted for portions of smaller monomers such as methyl methacrylate, methyl acrylate, ethyl methacrylate and ethyl acrylate. Other parameters which influence the rate of the curing reaction include the level of hydrazide or hydrazone functionality of the curing agent and the nature of the curing agent.
; For use as general industrial coatings, the use of aqueous emulsions comprising a composition containing acrolein-based emulsion polymers having a Tg of about 10-60C with dicarboxylic acid bis-hydrazides represented by the formula, B2N-NB-C(O)-R-C(O)-N~-N~2, wherein R is a member selected from the group consisting of diavlent , polymethylene groups having from 2 to 34 carbon atoms is ' especially advantageous in that such compositions demonstrate surprisingly suitable potlife stability, ambient cure and desirable coating properties.
In another a~pect, for use as general industrial coatings, the use of acrolein- or methacrolein-based polymers, of both aqueouC emulsion and solution types, ~ 35 with acrylate oligomeric and low molecular weight !
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~ ~ 62669 polymeric bydrazides or hydrazones are especially advantageous in that these curing agents are more easily obtained than their methacrylate analogs, in that potlife of coating compositions can be effectively S controlled by appropriate selection of the type and level of acrolein- or methacrolein-containing polymers and of the particular curing agent, and in that desirable ambient cure properties and desirable coating properties can be realized.
The compositions of the invention can, optionally, contain any of the additives conventionally used in coatings provided the additives are compatible with the composition. Examples of such additives include coalescents, conventional fillers, pigments, and the like. When aqueous emulsion aldehyde-containing polymers are used, it is most advantageous to add up to about 30~ by weight of a coalescent in preparing coating formulations to achieve best results, the amount of coalescent used being dependent on the characteristics of the particular polymer being used.
The following examples serve to further illustrate the invention but are not intended to limit it in any way. All parts and percentages are by weight and all temperatures are in degrees Centigrade, unless otherwise indicated.
The following list defines abbreviations used in the examples:
BA -butyl acrylate MMA -methyl methacrylate 30 MACO -methacrolein AA -acrylic acid t-~HP -t-butyl hydroperoxide MAA -methacrylic acid St -styrene 35 ACO -acrolein r ,:

~ J 626~9 AD~ -adipic dihydrazide AzDH -azelaic dihydrazide AzDHzn -azelaic dihydrazone EA -ethyl acrylate

5 BMA -butyl methacrylate HEA -hydroxyethyl acrylate PZN -polyhydrazone Example 1 This example illustrates a typical preparation of a random acrolein-containing copolymer BA/MMA/MAA/ACO =
53/40.7/1.30/5.0, Tg = 10C, using a gradual addition, reflux process as described in greater detail in U.S.
Patent 3,896,085 in the hands of the same assignee as is this application.
A monomer emulsion containing the following materials is prepared:
Ingredient Amount Water 720.0 g Sodium lauryl sulfate3.5 9 BA 929.0 9 MMA 213.4 9 MAA 22.8 9 ACO 87.7 g Into a 5-1., four-neck round bottom flask equipped with a stirrer, themometer and condenser, and nitrogen inlet are charged 738 g of water and 3.5 g. of sodium lauryl sulfate. The flask is flushed with nitrogen and after heating to about 85C, 66.0 9 of the monomer emulsion described above is added. After one minute 42 g of 14% aqueous sodium carbonate and 53.5 g of 16%
aqueous sodium persulfate are added consecutively.
After 15 minutes, gradual addition of the rest of the monomer emulsion is begun and carried out over a 3-hour period while maintaining the temperature at about 87-88C. During the final two hours of the addition of ,.

.

. .

1 1 62G~9 monomer emulsion, 200 g of a 2% aqueous sodium persulfate solution is gradually added at an even rate.
A temper~ture of 87-88C is maintained for one hour after completion of the addition of monomer emulsion.
The reaction is cooled to 60C rapidly and then allowed to cool at its own rate as a chaser system is added in three equal parts at 30 minute intervals. The chaser system is composed of two solutions: 2.25 g of tert-butylhydroperoxide in 30 g of water, and 3.4 g of sodium bisulfite in 120 9 of water. The bisulfite is added 2-5 minutes after the hydroperoxide (three times). After cooling to 24-30C, the reaction mixture is filtered through a 100-mesh screen to give the emulsion product.
Example 2 Heteropolymer Example The following example illustrates a typical preparation of an emulsion heteropolymer, 80 (BA/MMA/MAA/ACO = 53/40.7/1.30/5.0)//20 (BA/MMA/MAA =
56/42.7/1.3).
Monomer emulsions containing the following materials are prepared:
Amount Ingredient Emulsion IEmulsion II
Water 576.0 g 144.0 g Sodium lauryl sulfate2.~ g 0.7 g BA 743.2 9 196.3 9 MMA 570.7 g 149.7 9 MAA 18.2 9 4.6 9 ACO 70.2 g ---Into a 5-1., four-neck roundbottom flask equipped with a stirrer, thermometer and condenser, and nitrogen inlet are charged 738 9 of water and 3.5 g of sodium , lauryl sulfate. The flask is flushed with nitrogen and after heating to about 85C, 66.0 g of monomer emulsion ,. .
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- i J 626~9 I is added. After one minute 42 g of 14% aqueous sodium carbonate and 53.5 g of 16~ aqueous sodium persulfate are added consecutively. After lS minutes, gradual addition of the rest of the monomer emulslon is begun S and carried out over a 3-hour period while maintaining the te~perature at about 87-88C. Dur~ng the final two hours of the addition of ~onomer e~ulsion, 200 g of a 2%
aqueous sodium persulfate solution is gradually added at an even rate. A tcmperature of B7-88C is maintained for one hour aft~r completion of the addition of monomer emul~ion I. A 50 g portion of 2~ aqueous sodium t pcrsulfate is added in one portion, followed by gradual addition of monomer emulsion ~I over 45 minutes while maintaining a temperature of 87-88C. Twenty minutes after completion of the addition of monomer emulsion II, the reaction is cooled to 60-C rapidly and then allowed to cool at its own rate as a chaser system is added in three equal parts at 30 minute intervals. The chaser - system is co~poscd of two 501ut~ ons: 2.25 g of tert-butylhydroperoxide in 30 g of water, and 3.4 9 of sodium bisulfate in 120 9 of water. The bisulfite is added 2-5 minutes after the hydroperoxide (three times). After cooling to 24-30C, the reaction mixture i~ filtered through a lO0-mesh screen to give the emulsion product.
ExamPle 3 By following substantially the same procedure described in Example l, copolymer emulsions that . .
: are useful in the invention are prepared from monomer emulsions having the following weight ratios of monomers:
A. BA/MMA/MAA/ACO ~ 20/74/1/5.
B. BA/MMA/MAA/ACO/DVB ~ 55/37/3/5/0.09.
C. ~A/MMA/MAA/MACO ~ 20/74/l/5.

D. BA/MMA/MAA/MACO ~ 55/37/3/5.
E. BA/MMA/MAA/ACO ~ 55/37/3/5.
F. BA/MMA/MAA/ACO ~ 40/52/3/5.
G. 8A/AN/AA/ U O ~ 55/37/3/5.
~. BA/MMA/St/MAA/ACO ~ 40/34/20/1/5.
I. BA/~MA~Vinyl Acetate (~A)/MAA/ACO ~ 40/44/1/5 ~xample 4 A. This example illustrates a typical preparation of an acrolein-containing solution polymer, BA/MMA/St/ACO ~ 40/34/20/6.
In the preparation of this copolymer, the polyaeri~ation of the onomers is accomplished with a reaction flask equipped with a stirrer, condenser, nitrogen inlet, addition funnels and a thermometer.
Initially, there is charged to the reaction flask, 250 9 of ~ellosolve~acetate and 250 9 of n-butanol. Then, nitrogen is admitted into the flask and the solvents are heated to about 105C. At the solvent temperature of about 105C, the monomer mixture, consisting of 400 9 of butyl acrylate ~BA), 340 9 of methyl methacrylate (MMA), 200 9 of styrene (S) and 60 g of acrolein (Acj, is fed lnto the flaJk at a rate sufficient to be completed in : about 2.5 hours. At the same time, the initiator olution consisting of 40 9 of t-Butyl peroxypivalate ~57.8%) and 60 9 of'~ellosolve~acetate is fed at 4 rate _ sufficient to complete 90~ of it in 2.5 hours with the remainder over 30 minutes. After the addition of the . monomeric mixture and initiator solution to the flask, t the polymerization temperature of about 105C is maintained for 30 minutes. The monomer conversion at thls point is about 90%. Then, a second portion of inltiator solution, consisting of 8 9 of t-Butyl peroxypivalate and 10 9 of~Cellosolven*acetate, is added -at a rate sufficient to be completed in 30 minutes at a 3S temperature of about 105C. and the reaction mixture is * Trademark. "Cellosolve" acetate is ethylene glycol monoethyl ether acetate.

, . : ..
.. . .

- ~ .

held at about 105C for 30 ~inutes. The reaction aixture is finaliy cooled to room temperature and there is a conver~ion of about 96t based on the converted monomer.
B. This example illustrate6 another typical preparation of an acrolein-containing solution polymer, BA/MMA/St/AC0 ~ 34/26/20/20.
Into a reaction flask equipped with a stirrer, condenser, nitrogen inlet, additional funnels and thermometer was charged about 474.5 grams of butyl _"Cello~olve~' The flask was then flushed with nitrogen and after being heated to about 105C with the solvent being agitated, the monomer mixture (consisting of 340 9 of ethyl methacrylate, 260 9 of butyl acrylate, 200 9 15 of ~tyrene and 200 9 of acrolein) ~ith 60 9 of t-butyl peroctoate (50% in mineral spirit) was fed into the flask over a three(3) bour period. The flask was heated and cooled as required to hold the polymerization temperature at about 105C which was maintained for 30 minutes after the completion of the feed of the monomer mixture and t-butyl peroctoate. Then, over a 30 minutes period, there was added 24 9 of t-butyl peroctoate and _ 474.5 9 of butyl~Cellosolve~s* After this charging of the solvents, the reactor was held at a temperature of about lOSC. for about 30 minutes. At the end of this period, 24 g more of t-butyl peroctoate was added to the reaction mixture. The polymerization temperature of about 105C was held for another 30 minutes and then the polymerized ma~erial was cooled to about 70C. As analyzed by gas chromatography, the monomer conversion was about 99.4% and the available aldehyde was about 75%
ExamPle S
This example illustrates a typical preparation of a methacrolein-containing solution polymer, BA/MMA/St/MAC0 3S ~ 10/55/20/15.

* Trademark. sutyl "Cellosolve" is ethylene glycol f~ monobutyl ether.

I ~ 62669 Into ~ reactor equipped with a stirrer, conden~er, nitrogen inlet, addition funnels and a thermometer there _ is charged 135 9 of butyl"Cellosolve"* The reactor is then flushed with nitrogen and after the ~olvent is beated to about 105C, a monomer mixture consisting of 50 9 of butyl acrylate, 275 9 of ~ethyl methacrylate, lO0 g of styrene and 27.? 9 of t-butyl peroctoate (50%) ~ fed into the reactor over ~ peri~d of 2 hours. At the ~ame time over a period of 2.25 hours there is fed a lO _ ~econd ~onomer mixture of 25 9 of butyl Cellosolve*and 75 9 of ~ethacrolein while the temper~ture of the reactor Di~ture is ~aintained at about 105C.
I~mediately after the completion of the feeding of the fir~t ~onomer mi~ture, a solvent ~i~ture of 10 g of 15 _ butyl " ~ losolve"*~nd 2.3 9 of t-butyl peroctoate (50~) is fed ~nto tbe reactor sver a period of 0.25 hours so that it is completed at the same time as the second monomer mi~ture. ~he temperature of the Peaction mixture i~ then held at a temperature of about 105C for a period of O.S hours. Then, another solvent ~ixture - consisting of lO g of butyl~Cellosolve~and 4.8 9 of t-butyl peroctoate is fed over a period of 0.25 hours.
After this period of time, the reaction mi~ture ls held at about 105C for 1 hour, cooled and then the product is filtered through a 20 micron cartridge. In the resulting copolymer, there is about 94~ conversion and the available aldehyde ia 63% of theory.
~xample 6 By following substantially the same procedure described in Example 4, A or B, the following acrolein-containing solution polymers are prepared:
A. BA/MMA/St/ACO ~ 40/25/20/15 8. BA/MMA/St/ACO ~ 40/20/20/20.
C. BA/MMA/St/ACO/MAA ~ 21.2/45/20/11.8/2.
D. BA/MMA/St/ACO ~ 36/34/20/10.
*tr ademark .. . .

E. BA/MMA/St/ACO = 26/39/20/15.
F. BA/MMA/St/ACO = 26/34/20/20.
G. BA/MMA/St/ACO a 35/33.2/20/11.3.
Example 7 By following substantially the same procedure described in Example 5, the following methacrolein-containing solution polymers are prepared:
A. BA/MMA/St/MACO/MAA = 19.6/44.1/19~6/14.7/1.96.
B. BA/MMA/St/MACO ~ 20/45/20/15 C. BMA/St/MAA~MACO = 63/20/2/15.
D. BA/MMA/NAA/MACO = 62/35/1/2.
E. BA/MMA/MAA/MACO = 62/33/1/4.
Examples 8-19 illustrate the synthesis of hydrazide and hydrazone curing, i.e. crosslinking, agents.
Examp7e 8 Azelaic Acid Bis-hvdrazide (AzD~) A 2000 ml four-necked flask equipped with a thermometer, mechanical stirrer, Friedrich condenser, and 500 ml pressure-equalizing addition funnel is charged with 250 9 of 64% hydrazine hydrate (5.0 moles). The hydrazine is heated to 80C and a solution of 108 g dimethyl azelate (0.5 mole) in 75 9 2B ethanol is then added slowly to the flask over a period of 2.0 hours. During this process, the bishydrazide cryQtallizes from solution. The reaction mixture is stirred 1.0 hour longer at 80C whereupon it is cooled to ambient temperature, diluted with 100 ml of diethyl ether, stirred briefly, and filtered. Recrystallization of the filtered solid from water affords 88.5 g of product (82%), mp. 187-188C.
ExamPle 9 Azelaic Acid Bis-hydrazones (AzDHzn) A 250 ml three-necked flask equipped with a thermometer, mechanical stirrer, and Freidrich condenser is charged with 21.6 9 of azelaic acid bishydrazide (0.1 I 1 62~69 mol.e), 15 ml of glacial acetic acid, and 0.5 mole of the aldehyde or ketone. The mixture is heated at 50-80C
until complete solution is effected. When necessary, 50 ml of 2B ethanol is added as a diluent. Evaporation of the mixture in vacuo and crystallization of the residue from an appropriate solvent then affords the purified bishydraz.one. The products are summarized in the accompanying table.

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~xample 10 AdiPic Acid Bis-h~drazide_(AD~) By ~ollowing substantially the procedure described in Exa~ple 7 except for the substitution of dimethyl adipate for dimethyl ~zelate, ~dipic ~cid bis-hydrazide is prepared~
E~a~ ' Adipic Acid Bis-h~drazone (AD~zn) 8y following substantially the p~ocedure described in ~xample 8 except for the substitution of dimethyl adipate for dimethyl ~zelate, adipic acid bis-hydrazone ls prepared.
Esam~le 12 Di-er Acid Bis-h~drazide A 2000 ml four-necked flask equipped Yith a - thermometer, ~Ihermowatch~temperature regulator, mechanical stirrer, Friedrich condenser, ~nd 1000 ml pressure-equalizing addition funnel is charged with 250 ml of 64% hydrazine hydrate (5.0 moles). The hydrazine is heated to reflux ( 110C) and a solution of 294 g of dimer w id dimethyl ester (0.5 mole) in 240 9 of toluene is then added slowly to the flask over a period of 6.0 hours. The mixture is maintained at reflux 8.0 hours longer at which point it is cooled and transferred to a separating funnel to facilitate phase separation. The lower aqueou~ layer is discarded; the upper organic layer is thoroughly evaporated in vacuo (1.0 mm) at 95C to afford the product as a viscous pale yellow oil. Solids:
97.2%; Residual ~ydrazine ~iter: 0.10 meg/g; ~ydrazide . 30 functionality: 1.94.
Samples of the bishydrazide are converted to bishydrazones with acetone, methyl amyul ketone, and methyl isobutyl ketone,9respectively, via the procedure described in Example ~.
*tr~demsrk ,~ 9-f, ~sample 13 PreParation of Ethvl Acrylate Oliqomer A 5000 al four-necked flask equipped with a - thermometer, ~Thermowatch~*temperature regulator, conden~er, mechanical stirrer, and 2000 ml pressure-equalizing addition funnel fitted with a nitrogen ebullator iQ charged with 356.4 g of toluene And 70.56 g of potassium t-buto~ide (0.63 mole). ~he mixture is heated to 70-C and to lt is then added 3150 g of ethyl acrylate (31.5 molesl over a period of 2.0 hours at a rate sufficient to maintain the system at temperture. To complete the reaction, the mixture is held 2.0 hours longer at 70-C, then cooled, neutralized with 32.3 g of 98% sulfuric acid, and treated with 300 g of 33% aqueous aluminu~ sulfate ~olution to facilitate removal of the resultant salt~. Volatiles are removed by distillation in vacuo (30 mm) at 95-C and the residue is filtered .
under pressure to afford the product oligomer as a clear amber liquid. Solids: Brookfield ViscoQity: 9100 cps; Mw 2270s ~n 1060; Mw~Mn ~ 2.14; d.p. 10.6 ExamPle 14 PolYh~drazide Derived from Ethyl AcrYlate Oliqomer A 200 ml four-necked flask e~uipped with a ther~o~eter, ~echanical stirrer, and Friedrich condenser charged with 56.5 q of ethyl acrylate oligomer (~
Mw 2930, Mn 1130, d.p. 11.3, 0.05 ~ole) and 75 9 of 64%
hydrazine hydrate (1.5 moles). The mixture is heated under nitroqen at 95C for 1.5 hours. Excess hydrazine 1~ removed by distillation in vacuo ~30 mm) at 60C. The re~idue is dissolved in 25 ml of deionized water and the resulting olution is then diluted with 450 ml of absolute methanol to precipltate the product as a white powder. ~ydrazine functionality: 7.57 Perchloric Acid Titer: 7.54 meq/g; Elemental AnalyQis: Calculated for -C~2-C~-CON2~3; Carbon: 41.79~; ~ydrogen: 7.01~;

*trademark r~
i~

I ~ 62669 2g --Nitrogen: 32.64~; Found: Carbon: 40.75~; ~ydrogen: 6.95~;
Nitrogcn: 28.60~.
Example 15 Polvhydrazone ~erived_from ~utyl Acrylate Oliqomer A 1000 ml four-necked flask equipped with a _ thermo~eter, ~hermowatch-*temperature regulator, ~echanical.~tirrer,. and condenser is charged with 150 g of 2-~ethoxyethanol, ~60 g of butyl acrylate oligomer ~ ~~ Mw 2870, Mh 1230, d.p. 9~6, 0.374 mole), prepared by following ~ubstantially the sa~e procedure described in Esample 11, and 101.2 g of 6~% hydrazine hydrate (2.02 ~oles). The misture is h~ated under nitrogen ~t 85C for 4.0 hour~. E~cess hydrazine is then re~oved by di~tillation under reduced pre~sure (1.0 ~m) at 60C to gi~e the product. ~ydrazide functionality:
2.9.
The viscous polyhydrazide is heated ~ith 300 9 of ~cetone ~5.2 ~cles) and 1 ml of glacial acetic acid for 1.0 hour at 50-55C. Escess acetone and water are then removed by evaporation under reduced pressure (25-30 mm) at temperatures up to 50C. Dilution of the residue with 2-butosyethanol affords the polyhydrazone as a clear amber solution. Solids: 54.3%; Perchloric Acid Titer:
3.15 meqJg.
~xamPle 16 Polyhydrazone Derived from MethYl ~ethacrylate Oligomer A 1000 ml four-necked flask e~uipped with a thermometer, ~Thermowatch~*temperature regulator, mechanical ~tirrer, D0an-Stark trap, and condenser is charged 250 9 of methyl mothacrylate oligomer ~ ~w 732, Mn 645, d.p. 6.45, 0.388 mole), 85 9 of 2-methosyethanol, and 68 g of 64% hydrazine hydrate (1.36 moles). ~he misture is heated at 85C for 13 hours at which point the rate of consumption of the hydrazine decreased significantly. The byproduct methanol is then *tradem~rk .~

removed via the Dean-Stark trap to rai~e the reaction temperature to 115C. To complete the rea~tion, the ~ixture is maintained at temperature 18.5 hours longer.
The product polyhydrazide ~ then tre~ted with q50 ml of ~cetone at 60C ~or 3.0 hour~. Evaporation of the Dixture in vacuo (1.0 ~m) ~t 60-C5C ~nd dilution of the ~incous residue with 2-butosyethanol affords the polyhydrazone as a clear amber solution. Solids: 65.0~;
Perchlorl~ Acld Titer: 2.74 meq/g.
Bxample 17 Prc~ar~tion of 50 8A~50 MMA Poly~er A 5000 ~1 four-necked flask equipped wi~h a _ ther~ometer, $her~owatch-*te~peraturc regulator~
conden~er, ~ech~nical ~tirrer~ and 2000 ~1 pressure-equalizing addition funnel fitted ~ith a nitrogen ebullator is charged with 500 g of 2-butoxyethanol. The solvent is heated to 150]oC and a sparged ~ixture of 1000 g butyl acrylate ~7.8 ~oles), 1000 g ~ethyl methacrylate (10.0 mole5) ~ 20 9 mercaptoethanol (chain transfer agent - 1 wt. % on ~ono~er), and 80 g of a 75% solution of t-butyl peracet~te initiator in mineral spirits ~3 ~t. ~ on monomer) is then ~dded slowly to the flask over a period of 6.0 hours. The reaction mixture i~ held 0.25 hour longer at 150C, treated with 8.0 g of LuperQol 70 (0.25 hour) to chase residual monomer, ~nd then held an ~dditional 0.25 hour at temperature to afford the product polymer as a ~lear, dark yellow solution with the following specifications: Solids: 79.8~; Brookfield Visco6ity: 6,260 cps; ~w 5530, Mn 2310s ~w~n ~ 2.39, d.p. 20.2; Conversion: 96.5t (GLC).
Example 18 Polvhydrazide Derived from 50 BA/50 MMA Polymer A 1000 ml four-necked flask equipped with a 35 _ thermometer, Thermowatch~ te~perature regulator, *traden~ark r - ~ 1 62669 ~echanical ~tirrer, var~ble take-off distillation head and nitrogen ebullator 19 charged with 433 g of ~n 80~
~olution of 50 BA/S0 MMA polymer ( Mw 5s30, Mn 2310, d.p. 20.2, 0.15 m~le) ~n 2-buto~yethanol, 22.5 g of - 5 64~ hydr~z~ne hydrate, and 260 9 of 2-methoxyethanol.
The mi~ture is sparged with nitrogen and then heated 23 hours at 110C and 16 hours ~t 115-118C at which point the product polyhydrazide had the ~ollowing ~pec1fications: Residual Bydraz~ne Tlter: 0.04 ~eq/g;
Perchloric Acid Titer: 0.54 ~eq/g; Bydrazide fun~tionality: 2.~. The reaction mixture is then diluted ~lth 125 g of 2-butoxyethanol and then stripFed of - volatiles in vacuo (25-30 ~o) at 60~-70C to gi~e the product polyhydrazlde as a elear yellow orange ~olution in 2-butosyethanol. Solids: 85.1%; Perchloric Acid Si~er: 0.~5 meq/g.
Sa~ples of tbe polyhydrazide are ailuted ~ith additional 2-butoxyethanol and then treated with a two-fold e~cess of aceton-, ~ethyl ~myl ketone, and methyl isobutyl ketone, respectively, to afford the corre~ponding polyhydrazones.
TABLE TI
PolYhydrazones Derived Fro~ 50 BA/50 MMA PolYmer ~104 Brookfield ~etone Titer Solids Viscos~ty acetone 0.57 meq~g 59.9% 900 cps methyl amyl ketone 0.58 meq/g 60.2% 1100 cps mcthyl isobutyl ketone 0.58 meq/g 60.7~ 1250 cps Example 19 PolvhYdrazide Derived from 20 EA/~0 BMA Polymer A 1000 ml four-necked flask equ~pped with a thermometcr, ~Thermowatch~*temperature regulator, mechanical stirrer, variable take-off distillation head, *trademark ' ;

-- 32 _ ~nd nitrogen ebul~ator ls charged with 520 g of ~n 80~
~olution f 20 EA/80 BMA polymer ( Mw 4430, Mn 2080, d.p. 16.6, 0.20 mole) in 2-butoxyet~nol, 30 g of 64~ hydrazine hydrate (0.60 mole), and 312 9 of 2-methoYyethanol. The mixture is sparged with nitr~gen and then he~ted 17.5 bour~ at 110C and 39.0 hours at llB-120C at which point the product polyhydrazide has the following spe~ifi~2tions: Re~idual ~ydrazine ~iter 0.06 ~cq/~; Perchloric Acid T$ter: 0.583 me~g; ~ydrazi~e unctionality: 2.3. The reaction ~ixture is then ~tripped of volatiles in vacuo t25-35 ~m) at 60-70~ to give the product polyhydrazide as a h~zy light yellow ~olution in 2-buto~yethanol. Solids: 83.9S; Perchloric Acid Titer: 0.96 ~eq/g.
Samples of th~ polyhydrazide are treated with a t~o-fold e-cess of acetone, methyl amyl ~e~one, and ~ethyl ~sobutyl ketone, respectively, to produce the corresponding polyhydrazones.
TAB~E ~II
Polyhydrazones Perived From 20 EA~80 BMA Polymer ~C104 Brook~ield ~etone Titer Solids Viscosity acetone 0.84 meq/g 77.6% 13,125 cps methyl amyl ketone 0.82 meg/g 76.0% 7,875 cps 25 methyl isobutyl ketone 0.83 meq/g 80.8% 22,250 cps Exa~le 20 For purposes of evaluation clear films are ~ade of aldehyde-functional emulsion polymers and hydrazide curinq agents by blending into the emulsion poly~er the curing agent, the relative proportions being such as to provide a 1:1 ratio of hydrazide and aldehyde groups.
Af ter about 15 min., the curing agent is dissolved and _ with butyl~Cellosol7el~(50% aqueous solution) is added as a coalescent, and the resulting ~ixture is made basic to a p~ ~ 9.5 by ~dding concentrated (28%) ammonium *trademark lC

hydroxide. The results of the evaluation are set forth in Table IV below.
.

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~ ~ ~ m--~ ~ c~ ~ ~ o 0 o ~ _~ _ _ _ _ _ _ C) ~ ~ ~ o ~ ~7 ~; o 0 ~ ~q z ~ o ~ ~ ~5l __ _ _ _ _ _ _ _Ic) c : . ~ oo ~c~
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JJ ~ C J ~ em ~m ~ em em e~ ~m a~ 7~.rl C ~,a,1a~a ~a~a ~a :,1a ~a :~ --I ~ a~ ~1 0_1 0 --1 0 --I ~C ~-1 _l o ~ C O~O~ O~ o~o~ O~ o~ O~
0 ~ u ~ ~ m ~ u ~ a P. a ~ m ~ O u~ o ~ 1 62669 TABLE IV (continued) Polymer Compositions and Calcul_ted Tg Polymer A = 85 BA/7 MMA/3 MAA/5 Ac (Tg, -28C) Polymer B = 55 BA/37 MMA/3 MAA/5 AC (Tg, +10C) Polymer C = 70 BA/24 MMA/l MAA/5 MAc (Tg, -6C) Polymer D = 55 BA/37 MMA/3 MAA/5 MAc (Tg, +14C) Curing Agents .
ADH = Adipic Dihydrazide ODH = Oxalic Dihydrazide Example 21 A. Preparation of Paint FormuLations Using conventional methods the following paint formulations are prepared. The let-down components are added in the order listed.
Binder A: "RhoplexR AC-61"1 (Rohm and Haas Co.) Binder B: Copolymer of Example 3E//6.0% ADH and 5.0% butyl "Cellosolve" (on polymer solids) Binder C: Copolymer of Example 3F//5.5% ADH and 14.0% butyl "Cellosolve" (on polymer solids) Grind: A B C
TiO2, RCL-9 2 78.1578.,1578.15 "Tamol 731-325% 3.13 3.i3 3.,13 "Nopco NDW'i 0.58 0.58 0.,58 Propylene Glycol 18.14 18.14 ~8.14 Let-Down propylene glycol 16.15 16.5 16.5 "Nopco NDW" 0.8 0.8 0.8 Binder 4 162.1162.1 166.1 "Super-Ad-It" 0.3 0.3 0.3 H2O 5 Pre-Mix 4.0 4.0 4.0 "Triton GR-7" 0.6 0.6 0.6 QP 4400 (3.5%) -- 18.9 7.4 H~O -- -- 7.5 Paint PVC 22.8 22.8 22.8 Volume Solids 35.5 35.5 35.6 pH, initial/equilibrated 8.8/8.8 8.8~8.8 8.9/8.9 Visc (Xrebs Units), -- 78/87 72/77 init./equilibrated 1. Trademark for an aqueous acrylic copolymer dispersion.
2. Trademark for the sodium salt of polymeric carboxylic acid~
it is an anionic surfactant.
3. Trademark for a liquid defoaming agent.
4. Trademark for diphenyl mercuric dodecenyl succinate~l0~ mercury).
5. Trademark for dioctyl sodium sulfo succinate - a wetting agent.

.. ~, . . . .. . .. .

The physical properties of cured paint films of the formulatlons descr$bed above wh~ch are app~.led to Penopac*
substrates i5 described in Table V as ~ollow~:
Table V
5 Paint Film Data A B C
aeat-Age Stability 10 days 60C
Visc., Cp5., pre-oven 2100 2900 1700 Vi~c. ~ Cpfi., post-oven 3200 3500 1800 p8, pre-oven 8.9 8.8 8.9 p~, post-oven 8.4 8.0 8.1 Drawdown Gloss, 1 wk, 60/20 60/15 48~8 48/8 Abr~sive Scrub, Cyoles to Failure 1 wk ~r-dry, as is 950 350 365 2 wk air-dry, as is 1050 7S0 600 2 wk heat aged 1500~ 750 570 ~N (1.5 ~il fil~) 1 wk ~ir-dry 0.85 2 wk air-dry 1.05 3.16 13.7 Baked 16 hr., 60C 2.2S 3.54 13.3 Print ~1 lb., 1 hr 60DC) 1 wk air-dry 7 __ __ 2 wk air-dry 6, 7 8 9 4 wk air-dry 7 8 9 Baked 16 hr, 60C 7 8 9 81Ock (2 lb., 60C, listed oven time) 1 wk air-dry, as is, 20 min/4 hr 0/- -- --2 wk air-dry, as is, 20 min/4 hr 0/0 7/5 7/6 2 wk air-dry, heat aged 20 min/4 hr 0/0 6/5 7/5 4 wk, air-dry, as is, 20 min/4 hr 0/0 6/6 7/7 16 hr, 60C, as is, , 35 20 ~in/4 hr 0/0 6/6 7/7 Weathero~eter Data 0 hrs 1.8 3.6 13.7 500 hrs 5.2 3.5 16.9 1000 hrs 4.7 2.2 14.4 1400 hrs 5.4 1.8 14.6 1900 hrs 6.2 2.7 14.0 ( ~ *trademark ~;.

Table V (continued) Weathcrometer Data A B C
Glos~ (60/20) 0 hrs 56~19 48/8 48/9 500 hrs 46/17 20/2 18/2 1000 hrs 36/6 44/6 39/5 1400 hrs 22~2.7 42/6 39/5 1900 hrs 13/1 16/1 23/1 Mandrel Flex 0 hrs P 1/8 P 1/8 F 1/2 500 brs P 1/8 P 1~8 F 1/2 _ lSxamPle ZZ
Clear Pilms of Oliqomer-Based P~lYhydr~zones and Aldeh~de-Functional PolYmers.
For purposes of evaluation, clear films are ~ade of compositions of oligo~er-based polyhydrazones reacted with AC0- and ~AC0-contnining solution polymers.
A paint is prepared by blending about 50 parts of the aldehyae-containing polymer and a stoichiometric amount of the hydrazone are dissolved in about 100 parts of xylene.
The paint is then cast on 24 gauge'~onderite*"40 panels by a 7 mil openlng drawdown castor. The paints ~re dried, as de~cribed in Table Vl below, for 7 days at ambient temperature or at 140F.
Pot-life or gel time ~s the time, after blending the aldehyde-containing polymer and the hydrazone curing agent, for the blend to gel as determined by periodic manual st~rring of the blend with a ~tirring rod.
Film hardne~s is determined on a Tukon ~ardness Tester and is reported as Rnoop ~ardness Number (R~N).
Print resistance is determined by the relative amount of indentation of a test sample, compared with a standard, prepared by applying to Bonderite*panels the paint blend, coverlng the painted panels with 2~ sguare cheesecloth sguares, placing a leather disc smooth side down on the cheesecloth, adding weights on the leather so as to produce * Trademark for a corrosion- inhibiting chemical composition applied to metal su~ace.

1 ~ 62669 a 2 psi load on the cheesecloth, and placing this sandwich in an oven preheated and maintained at 180F for 2 hrs.
The Mandrel Bend test is a determination of the flexibility of a paint or coating. Samples of the coated S metal are bent over a series of mandrels, 1/8", 1/4" and 1/2" in diameter, by hand so as to form a U-shaped cross-section. The film is examined by visual means and through a 30 magnification power microscope. No signs of cracks in the film is rated zero and the scale increases with the severity of cracking to a rating of 10, representing a severely cracked film exhibiting complete delamination of the film from the substrate.
The physical properties of these films, presented in Table VI below, demonstrate that the compositions employed cure substantially at ambient conditions.

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Out 1 1 62~69 Examele 23 Clear Films of Oliqomer-Based PolyhYdrazides and Aldehvde-Functional E~ulsion Polvmers.
For purposes of evaluation, clear films are made of S compositions of an oligomer-based ethyl acrylate polyhydrazide reacted with AC0- and MAC0-containing polymers. The physical properties of these respective films are presented in Table VII below.
The aldehyde-functional emulsion polymers are treated - 10 with N~40H to obtain a p~ of about 9.0, and then are L blended, respectively, with 40% aqueous solution of thepolyhydrazide. Films are cast from the resulting dispersions on aluminum (Al) and'~onderite-lOOd *(B-1000) panels and cured at ambient temperature for about 4 to 7 15 days. The films are then exposed to different solvents, for thirty minutes at ambient temperature.

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Example 24 For purposes of evaluation, clear films are made, asdescribed in Example 22 above, from azelaic acid bis-hydrazones reacted with ACO- and MACO-containing polymers. The physical properties thereof are presented in Table VIII below. Yellowing is determined by means of a Eunterlab Colorimeter Model D25A-4 utilizing the Yellowness Index procedure ASTM D 1925.

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I ~ 62~j69 Example 23 For purposes of evaluation, clear films are made from dimer acid bis-hydrazide (Example 12) reacted with ACO- and MACO-containing solution polymers. The physical S properties of the films are presented in Table IX below.
Table IX
Clear Film Pro~r~ r~ A id ~ishydrazide and Carbonyl-Functional Polymers Polymer and Polymer Bishydrazide Solvent Resistance6_ Pencil Pencil Toluene Water Polymer Hardness KHN Hardness KHN (5 min) (30 min) Example 2B 0.8 H 9.0 disintegrated sl.
6D embrittled Example 2B 1.0 Example 2B 1.2 Example 2B 2.7 H6.8 softened no effect 20 7C badly 1 Stoichiometric blends of hydrazide and carbonyl functionality; films cured 5 days at ambient temperature on aluminum panels. After 30 minutes at 150C, the pencil hardness of films increased to 2H-3H with no appreciable change in solvent resistances. No yellowing was observed on bake.
2 Films of the polymers alone dissolve on exposure to toluene for 5 minutes. Water has no effect on the ACO- and MACO-based polymers after 30 minutes.

Claims (19)

WHAT IS CLAIMED IS:

1. An ambient or low-temperature curable polymer composition adapted to coat a rigid substrate comprising:
a. a polymer polymerized from a monomer mixture comprising (1) from about 0.25% to about 35% by weight of a polymerizable aldehyde, and (2) at least one copolymerizable mono-ethylenically unsaturated monomer selected from the group consisting of .alpha.,.beta. -ethylenically unsaturated carboxylic acid, (C1-C24)alkyl methacrylates, (C1-C24)alkyl acrylates, vinylidene halides, vinyl halides, (meth)acrylonitrile, vinyl esters, ethylene and alpha-olefins, acrylic and methacrylic acid esters of alcohol-ethers, vinyl ethers, styrene and alkyl-substituted styrenes and vinyl aromatics, the combination of monomers being selected to provide a Tg of the polymer of greater than about 0°C; and b. a curing agent comprising a member selected from the group consisting of a dicarboxylic acid bis-hydrazide represented by the formula, H2N-NH-C(O)-R-C(O)-NH-NH2, and a dicarboxylic acid bis-hydrazone represented by the formula R1R2C=N-NH-C(O)-R-C(O)-NH-N=CR1R2, and acrylic oligomers and low molecular weight acrylic solution polymers containing a plurality of pendant hydrazide groups of the formula -C(O)-NH-NH2 or hydrazone groups of the formula -(O)-NH-N=CR1R2, wherein R is a member selected from the group consisting of a divalent alkylene group or alicyclic group having from 0 to 34 carbon atoms and a divalent aromatic ring and Rl and R2 are selected from the group consisting of H and (C1-C6) alkyl and alicyclic groups, the amount of hydrazide or hydrazone compound being selected to provide a ratio of hydrazide or of hydrazone groups to aldehyde groups of the polymer in the dispersion of from about 1:2 to 2:1.

2. The composition of claim 1 wherein the polymer component comprises an aqueous emulsion polymer containing from about 30% to about 60% by weight resin solids polymerized from a monomer mixture comprising (1) from about 0.5% to about 10% by weight of a polymerizable aldehyde selected from the group consisting of acrolein and methacrolein, (2) from about 0.5% to about 10% by weight of an .alpha.,.beta. -ethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid and methacrylic acid, and (3) up to about 99% by weight of at least one copolymerizable monomer, the combination of the monomers being selected to provide a Tg of the polymer of from about +10°C to about 60°C.

3. The composition of claim 1 wherein the polymer component comprises an aqueous emulsion heteropolymer, containing from about 30% to about 60% by weight resin solids, the particles of which comprise (a) about 50 parts to 85 parts by weight of a first polymer having a Tg of greater than 0°C formed by emulsion polymerization of a first monomer mixture comprising (1) from about 0.5% to about 10% by weight of a polymerizable aldehyde selected from the group consisting of methacrolein and acrolein, (2) from about 0.5% to about 10% by weight of at least one .alpha.,.beta. -ethylenically unsaturated carboxylic acid, and (3) up to about 99% by weight of at least one copolymerizable mono-ethylenically unsaturated monomer; and (b) about 15 parts to 50 parts by weight of a second polymer having a Tg of about 60°C to about 0°C formed by emulsion polymerization, in the presence of the first polymer, of a second monomer mixture comprising at least one copolymerizable mono-ethylenically unsaturated monomer, the sum of the parts in the first monomer mixture and the second monomer mixture always being 100 parts by weight.

4. The composition of claim 1 wherein the polymer component comprises an aqueous emulsion polymer, containing from about 30% to about 60% by weight resin solids, polymerized from a monomer mixture comprising (1) from about 1% to about 7.5% by weight of acrolein, (2) from about 1% to about 7% by weight of at least one .alpha.,.beta.-ethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid and methacrylic acid, and (3) up to about 98% by weight of at least one monomer selected from the group consisting of (C1-C24) alkyl methacrylates, and (C1-C8) alkyl acrylates, the combination of the alkyl methacrylates and the alkyl acrylates being selected to provide a Tg of the polymer of from about +10°C to about 60°C.

5. The composition of claim 1 wherein the polymer component comprises a solution polymer polymerized from a monomer mixture comprising (1) from about 5% to about 30%
by weight of a polymerizable aldehyde selected from the group consisting of acrolein and methacrolein, (2) from about 0 to about 10% by weight of at least one .alpha.,.beta. -ethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid and methacrylic acid, and (3) up to about 99.25% of at least one member selected from the group consisting of (C1-C24) alkyl acrylates, (C1-C24) alkyl methacrylates, styrene and alkyl styrenes, and vinyl toluene.

6. The composition of claim 2 wherein the curing agent comprising a member selected from the group consisting of a dicarboxylic acid bis-hydrazide represented by the formula, H2N-NH-C(O)-R-C(O)-NH-NH2, and a dicarboxylic acid bis-hydrazone represented by the formula R1R2C=N-NH-C(O)-R-C(O)-NH-N=CR1R2, wherein R is a member selected from the group consisting of a divalent alkylene group and an alicyclic group having from 0 to 34 carbon atoms and a divalent aromatic ring and R1 and R2 are selected from the group consisting of H and (C1-C6) alkyl and alicyclic groups.

7. The composition of claim 3 wherein the curing agent comprising a member selected from the group consisting of a dicarboxylic acid bis-hydrazide represented by the formula, H2N-NH-C(O)-R-C(O)-NH-NH2, and a dicarboxylic acid bis-hydrazone represented by the formula R1R2C=N-NR-C(O)-R-C(O)-NH-N=CR1R2, wherein R is a member selected from the group consisting of a divalent alkylene group and an alicyclic group having from 0 to 34 carbon atoms and a divalent aromatic ring and R1 and R2 are selected from the group consisting of H and (C1-C6) alkyl and alicyclic groups.

8. The composition of claim 4 wherein the curing agent comprising a member selected from the group consisting of a dicarboxylic acid bis-hydrazide represented by the formula, H2N-NH-C(O)-R-C(O)-NH-NH2, and a dicarboxylic acid bis-hydrazone represented by the formula R1R2C=N-NH-C(O)-R-C(O)-NH-N=CR1R2, wherein R is a member selected from the group consisting of a divalent alkylene group and an alicyclic group having from 0 to 34 carbon atoms and a divalent aromatic ring and R1 and R2 are selected from the group consisting of H and (C1-C6) alkyl and alicyclic groups.

9. The composition of claim 8 wherein the curing agent comprising a member selected from the group consisting of a dicarboxylic acid bis-hydrazide represented by the formula, H2N-NH-C(O)-R-C(O)-NH-NH2, and a dicarboxylic acid bis-hydrazone represented by the formula R1R2C=N-NH-C(O)-R-C(O)-NH-N=CR1R2, wherein R is a divalent polymethylene group having from 0 to 7 carbon atoms and R1 and R2 are selected from the group consisting of H and (C1-C6) alkyl and alicyclic groups.

10. The composition of claim 5 wherein the curing agent comprises a member selected from the group consisting of oligomers comprising units from (C1-C4) alkyl esters of acrylic acid and methacrylic acid containing a plurality of pendant hydrazide or hydrazone groups and dicarboxylic acid bis-hydrazones represented by the formula R1R2C=N-NH-C(O)-R-C(O)-NH-N=CR1R2 wherein R1 and R2 are selected from the group consisting of H and (C1-C6) alkyl and alicyclic groups.

11. The composition of claim 10 wherein the curing agent comprises a member selected from the group consisting of oligomers comprising units from (C1-C4) alkyl esters of acrylic acid and methacrylic acid containing a plurality of pendant hydrazide or hydrazone groups.

12. A crosslinked coating carried on a rigid substrate obtained by the ambient or low-temperature curing of the composition of claim 1.

13. A crosslinked coating carried on a rigid substrate obtained by the ambient or low-temperature curing of the composition of claim 6.

14. A crosslinked coating composition carried on a rigid substrate obtained by the ambient or low-temperature curing of the composition of claim 7.

15. A crosslinked coating carried on a rigid substrate obtained by the ambient or low-temperature curing of the composition of claim 10.

16. An article of manufacture comprising a rigid substrate coated with the ambient or low-temperature cured composition of claim 1.

17. An article of manufacture comprising a rigid substrate coated with the ambient or low-temperature cured composition of claim 6.

18. An article of manufacture comprising a rigid substrate coated with the ambient or low-temperature cured composition of claim 7.

19. An article of manufacture comprising a rigid substrate coated with the ambient or low-temperature cured composition of claim 10.