CA1330606C - Epoxy-polyester graft copolymers suitable for chip resistant coating composition i" - Google Patents

Abstract

ABSTRACT

A hydroxy functional epoxy-polyester graft copolymer and novel, solvent-based thermosetting coating composition comprising said copolymer and polyfunctional, hydroxy-reactive crosslinking agent. The coating composition may be formulated as a hot sprayable, high solids coating composition suitable for use as a chip resistant automotive vehicle primer adapted for use on body panel areas subject to chipping by stones, gravel and other road debris. The composition may also be formulated as a high solids composition sprayable with conventional spraying equipment. Hydroxy-functional epoxy polyester graft copolymer is prepared by polymerization of lactone monomers in the presence of hydroxy functional epoxy ester resin precursor. The precursor is the reaction product of modified diepoxide and hydroxy functional secondary amine in about a 1:1 equivalent ratio. The modified diepoxide is the reaction product of polymerization of lactone monomers in the presence of diepoxide which has been reacted substantially simultaneously with diphenol and dicarboxylic acid.

Description

, .~ 33~a~
EPOXY-POLYES~ER GRAFT COPOLYME~S SUITABTF FOR
CHIP RESISTANT COATING COMPOSITION 1"

Technic~l ~'ield l`his inventiorl relate6 to a llovel hydroxy functional epoxy-polyester graft copolymer and to a eolvent-ba6ed, thermosetting coatin~ compositior comprising SUCIl copolymer ~nd polyfunctional, hydroxy-reactive crosslinkin~ a~ent. It relates al60 to 15 such coatin~ co~position formulated, for example, ds hot sprayable, hi~h solid6 coatiny compo6ition 6uitabl~
for u6e as a chip resistant automotive vehicle primer adapted for u6e on body panel areas subject ~o Cllippill~
by stone~, gravel dnd other road debris.
.
~ac~routld ¦ Automobile nldnufacturer6, in their effort6 to exteJId the expected life of automobile ~h~et met~l ~nd - I the like, haYe directed considerable atterltion to various proce66e6 and conlpo6ition6 desiyïled to result in llot only 25 improved corrosioll resi~tallce but al60 improved Cllip re6i6tance proeerties. In pdrticular, re6earcll and development efforts have recently-beeJI directed to obtainirlg primer compo6itiorls wl~ich are flexible and C~lip resistant and which ~ive corrosion protection w~ile - 2 - 133 ~0~

exhibiting good humidity and solvent resistance, a6 well as good intercoat adhe6ion. New automobile de6i~ns and concern about ChSppill9 in areas expo~ed to stones, yravel and other road debri6, e.g. rocker panels, have demailded 5 such c~ip resi6tant primer6 which can be applied in rea60nable t~ickne6~e6 by technique6 WlliCh do not require exten6ive and expen6ive proce66ing modification6 durin~
painting operatiosJ6. To date available p~imer~, wlletller high or low 601id6, have not proven particularly 6uitabl~.
ln order to overcome the aforementioned Cllippill~
problem it has been common to apply reldtively thick chip re6istant ccating6 in body panel region~, which are illclill~d to chip, prior to dpplicatioll of still dll~tll~r primer compo6itioll. One 6uch chip re6i8tdnt 6edl~r 15 materidl WlliCt~ llaS been elllplOyed i~ a polyvirlyl ctllorid~
pld~ti601 6ealer which has beerl applied with airle6s spraygun e~uipmen~ in thickneE6e6 of about 20 mil6 ir region~ subject to lli~h level6 of chipping. Problem~
attenddnt with 6uch t~ick coatiny6 are readily apparent.
20 ~ecau6e of the thickne6~ in tlle region to whicb it is applied, t~ese materials present an appearanc~ problem often re6ulting in wavine6s and roughnes6 in the findl coatiny on the sheet metal. Often timefi surfac~
imperfection6 also result from the fact that a pcimer is 25 applied over the top of tlli~ sealer, witll the primer and 6ealer being cured togetller. As a result so~e 601vent dnd plasticizer tend to be driven out of the polyvinyl c~lloride plasti601 and result in a wavy and rougtl surface. Still furtller problems associated Wi~tl the UBe 30 Of 6uch pOlyVillyl chloride pl~sti601 sedlers and the like iuvolve application tec~lnique. Sirlce tlle polyvinyl ctllorid~ pld6tisol ~ealer~ arld tlle like must be dpplied in thickne6se6 of 20 mils or greater in order ~o obtain ~ood adhe6ion, they c~nnot be fea~hered down to blend irl witb '' '~
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other region6 of the sheet metal which do not re~uire the additiondl chip protection. Thu6, the material6 mu6t b~
applied u6ing a mdskin~ technique whereby tbo6e regiorl~
which are not to be coated with the sealer mdteridl are 5 masked in a 6eparate operation prior to dpplicatiorl of 6ealer. This maskiny i8 then removed after the ~edler i6 applied. It would obviously be de~irable to elimitlate these ddditional seep6 in t~e dpplicatiosl of t~le chip re6istant sealer materidl.
Accordingly, it i8 a preferred object of this invention to provide a novel solve~lt based, t~lermosettirlg coating composition dddpt~d for use a~ a chip re~istan~
primer, which primer may be dpplied in thickne66es of le~s than 20 mil~ and whlch may be feathered in BUCII a manrler 15 as to blend with paint in other areas of the sub~trdte to be painted whietl do not require chip resi~tant codting.
It is a furt~ler object of the present invention to provide novel re6in6 suitable for use in solvent-ba6ed thermo6etting codting compo6itions. 1JI this regard, it i6 20 d particular object of the inventiosl to provide novel, hydroxy functiondl epoxy-polye~ter graft copolymer resirl6 which are cro~slirl~able during cure, orl the surface of d 6ub~trdte .
lt is ~nother object of the invention ~o provide novel coating compo6itions which compri~e crosslinkable hydroxy functiondl epoxy-polye6ter graft copolymers dnd cros61inkinq agent and wtlich provide higb clo6slinking efficiency and tough. well cured film~ at minimum ba~e temperatures such a~ when applied as automotive pri~ers.
In this regard, it is a particular object of tbe inve--tior to provide a novel hydroxy function~l epoxy-polye6ter/
cros~lin~ing ~gent thermo6ettiny coating co~position of 6ufficien~1y low Volatile Oryanic Con~ent (VOC) to aid in meeting governmentdl emi6sions guideline6 and yet whictl ::
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can be applied to a sub6trate by 6praying or other kl~own met~lod .
lt i6 another ob3ect of the invention to provide a composition which will form a coating on a 6ubstrate, 5 which coating ha6 advantageou6 phy6ical propertie6 i~cluding, for example, bumidity and solvent re6istance, flexibility and corro~ion protection for the urlderlying ~ub~trate .
Additional d~p~Ct6 alld ddVdrlta9e6 o t~
inv~otioll will be apparent from the following d~scri~tios~
thereof.

Di6clo6ure of the Invention Accordiny to the present inventioll, novel csosslinkable hydroxy functional epoxy-polye6ter graf t copolymer re6in6 are provided which are suitable for u6e in thermosettiny coating compo6ition6, and which are e6pecially ddvantageous for u6e in high ~olid6 arld chip re6istant, organic solvent based thermoseteing coating composition6. The hydroxy furlctional epoxy-polye6ter graft copolymer re6in6 of the in~entiorl preferably have a number averaqe molecular weight (Mn) of about 2,000 to about 20,000 and are the product of polymerization of lactone monomers in the pre6ence of hydroxy funceional epoxy e6ter re6in precur60r, wherein the polymerization reaction mixture compri6es betweerl about 10 alld about 80 weigh~ percellt of tlle bydroxy functional epoxy estee resir precursor and between about 90 and about 20 weigllt percellt lactone monomer6. The precur60r i6 the reaction product of: (i) modiied diepoxide being the product of polymerization of lactone monomer6 in the pre6ence of diepoxide which has been reacted sub6tantially 6imultaneou~1y with dip~enol and dicarboxylic acid. and . ` -.,- , , .. :
t,'.: ~

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j (ii) llydroxy functional 6econdary amine in ctlai termination reaction in about d 1: 1 eguivalent rdtio. ~h~
diepoxide i~ reacted 6ub~tantially 6imulta~leously Witll diphenol and dicarboxylic acid in amount6 6ufficient to 5 give a weight per epoxide (WPE) of between about S00 and about 2,500, preferably between about 500 and about 1,500. Preferably tlle diphenol and dicarboxylic acid are ¦ employed in a ratio of 10/90 to 90~10 by weiyllt. Tlle lactone monomer6 reacted to form the modified diepoxide 10 and ~he combin~d di~llellol ~nd di~arboxylic ~cid d~
~~ loy~d itl d IIIL)ldr rdtio of dt. l~d6L ~ bL~ t.iVI~Iy .
. Al60 accordillg to th~ pre6elJt illVeUti~ll, d nov~l, or~dslic solve~lt bdB~!d, tt~ermose~tirJg r~si~l/cro~lirlki~
ayent compo~ition. in dddition to ~olvent and any ~iyments 15 and ddditive6 6uch a6, for example, cdtaly~t, 10w control ayents and the like, comprise6 the hydroxy functiollal epoxy-polye6ter yraft copolymer re6i~l of the inven~ioll dnd polyfunctional, llydroxy-re~ctive cro661in~iny ayent.
Preferably, 6uch cro6slinking agent iB 6elected from (1 20 aminopla6t cro661inking agent 6uch a6, for example, hexamethoxy me~hyl melamine, ~2) bloched polyi60cyalldte cro6slinking ayent including, but not limited to, blocked I trifunctional i60cyanurate ring containing polyi60cyarlate6 ¦ and oliyoe~ter modified blocked isocyanateB, and t3) 1 25 co~patible mixture of any of them.
Particularly preferred compo6itious of tlle inverltion are tho6e formulated as high solid~ coating eompo6itions having sQlid6 levels in the range of 65-80S
solid6 and whicll are applied a6 cbip resi~tallt primer6 iJI
30 tllose dred6 of automotive panels, such a6 rocher pallel whicll are exposed to higll level~ of chippillg. SUCh compositions mdy be applied in thichne~6e~ ranging frum 1 to 25 mils wet to obtain findl coating~ is~ tll~ rdnge of 1 to 12 ~il6 dry, and mdy be fea~llered down to ble~ld in with , ~,, .
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paint applied to regions out6ide that requiring ddditiondl chip re6ist~nce protection. Generally, tlle compo6itio of this ~olid~ leve~ may be applied U~ y hot ~pr~y I eguipment at temperature~ in the range of room temperdture ¦ S iB about 77C to about 160F.
¦ Other preferred compo6ition6 of ttle invencioll are ¦ tho6e formulated a6 hi~h solid6 coating compo~itions ¦ ~dapted to be dpplied by conventional 6praying onto a 6ub6trate. These hiyh 601id~ coatiny COmpO~itiO116 01ay 10 tlave a ~olids level in the range of 50-60~ and ae~
especi~lly u6eful a6 a primer coating on the bare, unpoli6hed metal ~urface of an automotive vehicle. As u6ed herein, a high 601id6 coatiny COmpO6itiOrl i6 Olle having a volatile or~anic content of about 4799/1 (4.0 lS lb./gal.) or les6.
Other feature6 and advaJItage6 of thiB illV~lltion will become more apparent from the following, detailed description thereof including the preferred embodim~llt~
a;ld be6t mode of carryillg out thiB illVentiO~I.

20Detailed De6criDtion of the Inventioll More 6peciically, the invention reldte~ to a novel ~ydroxy functiondl epoxy-polyester yraft copolymer ! 6uitable for u6e in a thermo6ettillg compo~ition and ~o d thermosettinu compo6ition comprisiny that hydroxy functional graft copolymer and a polyfunctional, hydroxy-reactive cro~61inki~1y agent.
The novel, epoxy-polyester graft copolymer peeferably ha6 a number average molecular weight (Ml,) of between about 2,000 and about ZO,OOO and i8 the product of polymerization of lactone mo~omer6 in the preseuce of hydroxy functional epoxy ester resin precur~or, wherein the polymerization reactioll mixture preferably comprises .~

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between about 10 and about ~0 weight percent hydroxy functiondl epoxy e6ter resin precur60r and between about 90 and about 20 weight peecent lactone monomer~.
Preferably, the polymerization reaction mixture-compri6e~
5 between about 35 and about 65 weight percent llydroxy functional epoxy ester re6in precur60r and between about 65 and about 35 W~i9)1t percerlt lactoll~ monomer6. T~le hydroxy functional epoxy ester re6ill precur~or i6 t~
reaction product of: (i) modified di~poxide ~nd (ii) 10 llydroxy functiondl ~ecollddry amiTIe in chdill termillation reactiorl in about 1:1 e~uivalent ratio (i.~., of ~poxide to amine groups). The modified diepoxide its~lf i6 the product of polymeriza~ioll of ldctone monom~r~ in t~l~
pre6ence of diepoxide whicb ha6 been chaill extellded sub6tantidlly simultdn~ously witll diphellol and dicarboxylic ~cid, wherein tbe lactone monomer6 reacted t~
form the modified diepoxide and the combined diphellol dnd dicarboxylic acid are employed in a moldr ratio of dt lea6~ abou~ 2:1, respecLively. ~r~e di~enol dlld dicarboxylic acid are reacted 6ubs~antially simultaneou61y with diepoxide in amount6 6ufficient to give a weight per epoxide (WPE) of between about 500 and about 2,500, preferably between sbout 500 and about 1,500. Preferably ths diphenol and dicarboxylic acid are employed in a ratio of 10~90 to 90/10 by w~iy~t. The polymerization of ldctone monomer6 with t~le precur60r and tbe polymeriza-ion of the lactolle ~onom~r6 with tlle c~lain ex~ended die~oxide i6 ~enerdlly carried out at a ten~peraCure between abou~
50C alld about 300C, preferably at d te~perdtur~ of between about 1~0C and about 200C.
T~lermo6ettiDg co~positions of the invelltioll co~pri6e the dbove hydroxy functiollal qraft copolymer d~-d polyfunctiollal, hydroxy-reactive cro6slin~iny agent. Each of the above major component6 of tlle CO~pO~itiOI16 a6 well Ç~' _ 9 _ 13~ 6 a6 other component~ and other a6pect6 of the invention are de6cribed hereinafter in yreater detail.

A. Hvdrox~ Functional EDoxY-Polve6ter Graft CoDelvmer As de6cribed above, thi6 copolymer i6 the product 5 of polymerization of lactone monomer in the presence of an hydroxy functional epoxy ester resin precursor which it~elf i6 t~e reaction product of modified diepoxide and hydroxy functional 6econdary amine in chain termination reaction. The modified diepoxide it6elf i~ the produc~ o~
10 lactone monomers in the presence of diepoxide which ha~
been c~ain extended 6ubstantially 6imultaneou61y with diphenol and dicarboxylic acid.
It i6 believed to be a significant characterizing a6pect of the hydroxy functional epoxy-polye6ter graft 15 copolymer of the invention that the polymerized lactone portion of the hydroxy functional epoxy-polyester graft copolymer give6 tlle copolymer flexibility as well a6 toughnes6, two key propertie6 when choosing a primer for u6e in area6 susceptible to chipping. It i6 a further 20 characterizing aspect of the copolymer that it includes epoxy re6in portion6, i.e. ~ydroxyl terminated epoxy ester re6in precurBor iB u6ed a6 an initiator to form the graft copolymer, wl~ich give the copolymer excellent corro6ion - re6istance properties. Still further, becau6e the graft 25 copolymer6 of tbe invention are branched, they require a minimum amount of cro661inking in order to obtain a 6uitable net~ork for good coating integrity.

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133~
g Preferred hydroxy functiorlal epoxy-polyest~r yraft copolymers of the invention include significallt aroma~ic cont~ut which i8 believed to en~lance corro~io resistance propertie6. Even though aromatics tend to S i~lcrease the brittlene66 of polymers alld co~positioll6 includiny 6uch polynler6, it i6 po66ible to include them ~ince, d8 nlentioned above, the polym~riz~d lacton~ portio of tlle hydroxy functiolldl epoxy-polye~ter graft copolymer give6 the polymer illcrea6ed flexibility whicll, in 10 preferred embodiment~, more tllall comperl6at~ for dny ~uc brittlene6s. A particularly preferr~d embodiment of ~he hydroxy functional epoxy-polye6ter yraft copolymer re~iu of the invention is prepared from aromatic containin~
diepoxide. A1BO~ as di6cussed hereafter, the dicarboxylic 15 acid reactant employed in preparation of the hydroxy functional epoxy-ester resin precursor may al60 i aroma~ic uni~6.
Each of the reactants employed in the preparatiou of the hydroxy functiollal epoxy-polyester graft co~olymer 20 i8 described in greater detail below.

(i) DiePoxide Reactant W~ e, Ultillld~ely, ttle CllOiCe of the di~poxide redctdnt for prepdring the hydroxy functiollal epoxy e~ter resill pre~ur60r will depelld to an ext~nt UpOII tlle particular application intended for tlle codtiny compositioll, eerminal diepoxides, that iB diepoxide~
bearing two terminal epoxide yroup6, are generally most preferred. Tlle~e are generally more reaceive a~ld therefore require reaction conditions under which unde6irable side reactions, for example, ep~xy-epoxy reaction6 and gellation, can be more easily avoided. T~
diepoxide~ which are to be chaill extended wit~l ~he R~`'-` :. ' .

lo 133~

diphenol alld dicarboxylic acid may be selected from numerou6 diepoxide~, 60me o~ whicll may be diptl~nol extended diepoxides.
Diepoxy re6in6 not previou61y extended wit~
5 diphenol al~o may be used in the preparatiou of the hydeoxy functio~lal epoxy e6ter resin precur60e. Preferred diepoxy re6in6 of thi~ type include: Epon 828 (tradema~k) and Epon H29 (trademark), w~icll ar~ norl-extelld~d diepoxides of the Epon (trademdrk) Series, Shell Ch~mic~l 10 Co., Hou6toll, Texa0, a6 well a6 cycloaliphdtic diepoxy resills~ 8UCII d6 the ~pollex (trddemark) s~ri~, S~lell CllemiCdl Compdny; hydcllltOil~ epoXy re~:ill8 E~UCh dl;, for example, Re6in XB2793 (tcddemdrk, Cibd-G~igy Corpora~ioll, Ard~ley, New Yorh); dsld dlly of a wide variety of acyclic 15 or cyclic dliphatic diepoxides 6uch a6, for example, 1,4-butanediol diglycidyl ether and 4--vinylcyclo}lexelle dioxide drld the like. SLill otller suitabl~ diepoxides which may be chai~l exterlded Wittl dicarboxylic acid arld used in 6ynthe6iziny tlle epoxy-e6ter re6in precur60r are 20 commercially available and will be apparellt to the 6killed of the art in view of the pre6ent di6closure.
Diepoxide6 previously extended witll diphellol may be u6ed in ormitlg the precursor and numerous BUCh material6 are commercially available. These includ~
25 certaill of the well k~lown bisphe~lol-A epichlolohydri epoxy resin6 of the afolementioned Epou (trademar~) series, e.g. Epo~l 1000 dlld Eporl 1004 dlld tbe DER
~trademark3 ~erie~, Dow Chemical CompalJy, Midldlld, Michiy~ll, e.g., ~R 332. Th~e diglycidyi e~h~r bi6ph~ll01-A r~6ill~, or }li~tler mol~culdr w~ig~t dlldloy~
thereof, are mo6~ preferred in vi~w of their c06~ alld commercial availabllity.
Al60, it will be u~lderstood from the foregoi~ly that ally mix~ure of compa~ible diepoxide6 ~ay be u6~d.

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In ~ddition to ~he diepoxid~, a portion of t~le epoxy functionality can be provided by any conlpatibl~
monoepoxy compoulld or polyepoxy compound or mix~ur~ of 6uch compoulld6. ~le polyepoxide can be any of tlle well 5 known types 8uch d~ polyylycidyl ether6 of polyphenol~.
The6e can be produced by etherif iCatiOII of polyp~lenol Wit~l epihalohydrin in t~e presence o~ alkali. It will be recognized by the skilled of the art in view of the pre~ent di6clo6ure, that in some instances. pdrticularly 10 where a coating compo6ition of high 601idh contetlt iB 1~66 important, it may be de6irable to incorporate polye~oxide of higher molecular weight. Preferably, any BUCtl polyepoxide contains free hydroxyl grou~s in additioli to epoxide groups.
While polyglycidyl ether6 of polypberlol carl be employed, it mdy be de6irable to react a portion of t~le r~active ~ite~ (hydroxyl or in Bome inBtdllces epoXy) wit a modifying mateeidl to vary the film cbdracteri~tics of ~he re~in. The epoxy re~in may be modified, for example, 20 with isocydnate group contaillin~ org~nic material~ or ot~ler reactive organic mdterial6.
~ Other useful polyepoxides are the noYolak re6ills includiny, for ~xdmple, the novolak epoxy r~in~ ECN 1235 (trademark) and ECN 1273 (trademar~), Ciba-Geigy CorporatiO~I, According to preferred embodiment6 of the pre6en~
invention, epoxide compound6 other thalI diepoxide compound~ provide no more than about 15t and nlo6t preferably 6ub6tantiàlly none of the total ~poxide func~ionality in the reactants used to fornl t~le epoYy-eGter resill preour-or.

~- , , .' - 12 - 133~

(ii) Di~)!enol Reac~ant The diphenol redctant6 ~uiSable for reaction Wi~}l the diepoxide reactant and dicarboxylic acid il~ chais eXten6iOI~ reactioI~ include rlumerous commercially avdilabl~
5 material6 mdrly of w~ich will be reddily appareIlt to the ~illed of the art iu view of ~lle pre~ellt di~lo~uc~.
Preferred di~he~ol6 hdve tbe general formuld (I):

HO - ~ - R - ~ - O~ (I) wllereiIl R iB a divalent linking moiety sub~tdlltidlly 10 uIIredc~ive with ~he diepoxid~ re~ . Preferably R i6 d divalent orgaIIic linkillg moiety for exampl~ (CH2)~l where n i6 preferably from about 1 to about 0 C~0 dIId the lihe althouyh inoryallic moietie~ or example ~ulfonyl al~d the lihe are al60 6uitable. Di~2lenol6 of thi6 c~aracter have beell found to provide good reactivi~y with diepoxides de~cribed above and to prcvid~
ulLimately cured coating~ of the invelltio~ avi excellent ~hy6ical proper~ie6 mo6t notably excellell~
corrosion protection. It will be apparellt to the 6killed 20 of the art in view of the pre6ent di~clo6ure t~at R 6hould be 6ub~tantially unreactive with tbe acid co~porlellt employed in preparation of the epoxy e6ter re6in precur60r. Particularly preferred dip~enol~ iuclude tllo~e according to formuld (I) above whereiIl R i~ ~elected from the group comprisiny a strdight or branclled alkylerle or dlkylideoe moiety of olle to about lO carbon6 preferably baving three to four cdrbozls al~d mo6t preferably llaving the yeneral formula:

~ . .

r. . ~, 1 3 3 ~

R
- C -R
wherein R and R are the same or different d~ld each i6 a 5 monovalent organic moiety preferably ~elect~d fron~ t~e yroup compei6in~ ~ydro~en and lower alkyl of about o~e to four carbon6 mo6t preferably one or two carbon6 and the like or a mix~ure of any of them. Preferably the diphellol ~a6 a ~lumber average molecular weight (M ) betweerl about 10 1~0 and about 500 ~ore preferably between about 180 ~nd about 250. SUCh diphenol~ includ~ for exdmple bi~phel-Ol-A, which i6 mo6t preferred bisphellol-B
bi6phenol-F and d compatible mixture of dny of thenl. A~
u6ed bereil~ the term diphenol m~y include for example lS compoulld6 compri6iny a 6ingle di~lydroxy sub6~i~u~ed p~lellyl ~ rill~ ~UC~I d6 benz~llediol. More pr~ferr~d bowe~r ~re ¦ tho6e dip~erlol~ ~rovidin~ two termin~l mono-llydroxy ub6titut~d ph~nyl ritlg~ 6uc~ dB il~ fOrmUld (1), abov~.
Other example6 of dipllellols ar~ bis-(4-~lydroxy-t~r~-20 butylp~lenyl)2 2-propdn~ bi6-(~ydroxy-nap~lthyl)-m~ldlle and 1 5-dihydroxynapht~lalene. Other suitdbl~ dipllellol~
useful to form t~le epoxy ester re~in of tlle prese invention will be ~pparent to t2le 6killed of the art is view of t~e pre~ent di6closure.

25 (iii) Dicarboxvlic Acid Reactant Dicarboxylic acid~ 6uit~ble for cllaill ext~l-di~
diepoxides di6cus6ed above preferably bave a llu~ber averaye molecular wei~ht of between abou~ 145 and db4ut 9 1000 arld ~ore preferably betweell about 400 and dbout 600.
¦ 30 Suitabl~ dicdrboxylic acid~ include l~umerous co-~rci~lly 133~Q~

a~ailable materials, many of WhiCIl will be readily apparent to ~tle skilled of the art in vie~ of ttle pre~en~
disclosure. Suita~le dicarboxylic ac1ds lt~clude 6d~ura~ed or un~dturated, cyclic or dcyclic, aliphatic ot, drom~tic 5 dic~rboxylic acid6 or d mixture thereof. Acyclic aliehdtic dicarboxylic dcid~ are generally preferred in view of the entldrlced flexibili~y they provide to the cured coating6 of tlle invelltiorl. Preferred dicdrboxylic acid~
have the general formuld (Il):

HOOC - R''' - COOH (lI) wherein R is a divalent linkiny moiety ~ubstantially unredctive witb the diepoxide re6in. It will be apparent to the skilled of the art in view of the present di6closure, that R~ 6hould be 6ub6talltially unreactive 15 also with the acid component employed in prepardtion of the epoxy ester re6in precur00r, al~d with hydroxy fu~lctionality (yenerated in the chain-extell6iorl reaction). Preferably R'~ divalent, orgallic, linkillg moie~y. Particularly preferred are t~lo~e 20 dicarboxylic acid6 wher~ R~'~ i6 6elected from tbe grou~
compri~illg ~ 6trdight or branclled alkylene or dlkylidene moiety, preferably of dbout 4-42 cdrbon6, for example, (CHz)l whereill n i~ preferdbly from dbout 4 ~o ~bout 42, dnd the like or a mixture thereof. Dicarboxylic acid~
of tlli6 chardcter hdve been found to provide yood reactivity wi~h tbe pr~ferred diepoxide6 de6cribed dboYe and to provide, ul~imately, cured coating6 of ~he invelltion ~aving excellent p~lysical propertie~, most notably excellent flexibility and corrosion protection.
Exemplary dicarboxylic acids iDclude adipic acid, 3,3-dimethylpelltanedioic acid, ben2enedicarboxylic acid, phenylenediethanoic dCid, naphthaletledicarboxylic dCid~

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pimelic acid, suberic acid, azelaic acid, 6ebdcic acid, and the like or a compatible mixture of any of them. The anhydrides of the6e acid6, where t~e dnhydrides exist, are, of cour~e, embraced ill the term "acid" since tll~
5 reaction product6 obtained therefrom are the same. Wbile dicarboxylic acid6 accordiny to formuld (II) can b~ us~d whereiJI R''' iB an alkyl~ne chaiu of les8 t~las~ 4 c~rbo for example, oxdlic acid, malonic ~cid, 6uccinic acid, glutaric acid and the like, the6e are les~ preferred iJI
10 view of tlle somewbat lesser degr~e of fl~xibilicy provided tllereby. Preferdbly th~ dicarboxylic acid provide6 two t~rmindl cdrboxyl group6. Simildrly, ~ref~rr~d dromd~ic dicarboxylic dcid~ dre t)lose wllereill tlle cdrboxylic yroup~
are more ~pac~d dpdr~, for exdm~1e, 1,4-benze~
15 dicdrboxylic dcid dlld 2,~-naplltlldlelledicarooxylic acid.
Tll~ mo6t preferred dicarboxylic dcid6 are Bub6ta~ltidlly 6dtu~dt~d, acyclic, d1iplldtic dim~r dcid6, wllicb are well knowll to ~e ~killed of t~e art dl~d reddily commercidlly avdildble. ~lese are typically tll~
20 dimeriza~iorl reaction product6 of fatty acids wllich bdve from 4 to 22 carbon6 and a terminal carboxyl yroup. Of these, dimer acid of 36 carbon~ i8 mo6t preferred 6ince i~
provide6 excellellt reactivity with the preferred diepoxide6 dc6cribed above, provides epoxy ester reaction 25 product6 of ddvdntageou61y wide molecular wei~ht distribu~ion, ~nd provide6, ultimately, cured coatin~ of tlle invention ~laviny excellent pllysicdl proper~i~6. lu dddi~ion, dimer dcid of 36 CdrbO~18 iB r~adily commercidlly dvailab1e, for exdmple, ds ~mpol 1014 (trademark), ~mpol 30 1016 (trddemdrk) aud ~mpol 1018 (trddemdrk), ~dch ~
avdildble from Emery llldu~-ries, lnc., cillcilllldti, OlliO. ~ ~:
It ~llould be reco~llized thdt mo~t or dll comm~rci~lly dvdildble di~er dcids COII~dill som~ ~ortion of trim~r dcid, typic~lly, fot example, dbou~ 5-10% but in ~ome case6 ~B

, . - - ' ~;,', .: ' : :

- 16 - 13~
;

I mUCtl dS 30% or more, a11d al~o Col1tdit1 d USUdlly 6mdller ¦ portiol1 of monocarboxylic acid. A~ used l1erei~ l1e term ~dimer acid~ include6 t}1o6e con~ainil1y ~uch amuu~1t6 of ~ t~ese materials. Mo6t useful is the present cQmpositiol16 ¦ S are product6 that contail1 mostly diba~ic dcid dlld llolle or low amount6 of triba6ic and mol1oba6ic acid6.
Aliphatic dicarboxylic acids are 6eer1 to provide additional advantage6. In particular, while not wishil1y to be bound by t~1eory, it is presently under6tood tbat lO epoxy-polye6ter re~in ~raft copolymers prepared from epoxy ester re6in precursor~ derived therefrom wet the sub6trate 6urface better and pro~ide enhanced adhe6ioll between tt1e sub6trate and the cu~ed coating. They also flow be~ter and, thu6, provide an excellen~ smoot~1 ~urface UpOII beill9 15 cured. Also, the aliphatic u~1its provide enhdl1ced flexibility to tl1e cured coatil1y, d6 noted dbove, al1d thi6 flexibility of t21e coatinq i6 6een to provide ent1~l1ced impdCt reSi6tdl1Ce, d fedtUre eVell more t1iyhly de6irdble for chip re6i8tdrlt COdtil~y embOdimeTlt~.
Where corrosiol~ protection for the ~ub~trate i~
in~portant, it may be preferred to employ dicdrboxylic ~cid according to formul~ (II) above whereir1 R~ iB, dt leaB~
i~1 part, aromdtic. As noted above, it is believed that suc~ aroma~ic6 iu the coating compo6ition of tl1e ¦ 25 inventior1, such d8 a primer conlposition for a metdl 1 6ubstrate, are more resistant to ~ydrolysis thdn are aliphatic6 and, t~1erefore, pcovide enhdl1ced corro~iol1 and moi6ture resistance. Of cour6e, d8 also r1oted above, according to preferred embodiments of the epoxy e6ter 30 re6in precursor, de6cribed above, the diepoxide redcta provides aromatic Ul1it6 to tbe resin dnd this would simildrly contribute to corrosio~1 and moi~ture resis~dnce.
Othel 6uitabl~ dicarboxylic acids for the epoxy ester re~in of tb~ plesel1t inve11tiot1 will bo app~re;1t ~o 35 the 6killed of t11e art in view of t~1e present di6clo6ure.

~ . .

~. , ~;~

~` 133~Q~
- 17 _ Preferably, th~ chaill extended di~poxid~ ~IdS d uumber averaye molecular wei~ht ~M ) between about 1,200 and about 3,500, alld mor~ pref~rably bet~een about 1,600 and about Z,400.

(iv) Ldctone Mollomer6 The l~ctone r~dctant may be dny l~ctone, or COmbirlatiOIl of ldCtOlle6, hdVitl9 at l~aBt t~iX CdrbOII i~tom8, for example, from ~ix to eiyht carboll atom~, in tll~ riny and at ledst one 2Iydrogell substituellt on tlle carboll dtom 10 whictl is a~tached to ~he oxy uroup in ~aid rinU. 1l~ oll~
a6pect, the lactone used a~ a reactallt can be repre~e~lt~d by tlle generdl formul~:

RCH(CR2)n~' O

in WtliCII n is at lea~t four, for example, from four to 6ix, dt lea6t n~2R'6 are llydrogell, and the remainin~ R's are sub6tituellts 6elected from the yroup COllBiStill9 ~f ~ydrogen, alkyl. cycloalkyl, alkoxy and sinyl~ ri~lu aroma~ic hydrocdrbon r~dical6. Ldctolle~ havill~ yreater llumber~ of substituellt~ other thall llydrogell oll t}l~ ri~ly, ~nd ldctone6 ll~vi~ly fiv~ or le~6 carboll atom~ in ttle ring, dre cou~ideLed unsuitable for the purpo6e~ of the invelltio~l becau6e of the tèndellcy thdt pOlymerB tbereof bave to revert to tl~e monomer, particuldrly at elevdted temperdture.

.- :,.,~ - . : . . . . .
!i '` ~ ~ ' ; ' ::
~;, ' ' ' . ' .: . -133~

Tll~ lactone6 pr~ferred in thi6 inVelltiOII ar~ th~
ep8ilotl-cdprolac1;oll~B ~laving the yell~rdl fOrmUld:

R R R R R
H-C-C-C-C-C-C~0 ¦ R R R R ¦

wherein at lea6t 6iX of the R~ B are hydrogell and Lhe remairlder are hydrogen, alkyl, cycloalkyl, alkoxy or single ring aromatic hydrocarbo~l radicals, slone of tlle 10 substituent6 contain more thdn abou~ twelve carbon atonl~, and the totdl number of carboll atoms in the sub6tituellt6 on a lacton~ rin~ doe6 not exceed about twelve.
Un6ub~tituted epsiloll- caproldctone, in wllicll all ~lle R~
are hydrogerl, iB derived from 6-hydroxy~exa2l0ic dcid dnd 5 i6 mo~t preferred. Sub~ uted ep~ilorl-cdproldctolle6, ~nd mix~ure~ thereof, dre dvailable by reactill~ d correspondiny 6ub~tituted cyclo)lexdllolle Wit~l dn OXidi~i~l9 d~ent such as peracetic acid.
Amung ~he 6ubstituted epsilon-caprolac~o~es 20 co~l6idered mos~ 6uitable for t~le purposes of th~ illVeiltiOII
are the variou6 monoalkyl ep6ilon-cdprolactones such d8 the monometbyl , monoethyl-, monopropyl-, monoi~opropyl-, etc. to monododecyl epsilorl-caprQldctosles; dialkyl ep6ilon-caprolactosles in whic~l the two alkyl groups ar~
25 sub6tituted on the same or dif~erent carbon atom6, but not bottl on t~le epsilon carbon atom; trialkyl ep6ilon-caprolactone6 in which two or three carboll atom~
in the lactone riug are sub6tituted, so lon~ as the epsilon carbon atom is not distributed; alkoxy 30 ep6iloJI-caprolactone6 such as ~ethoxy dnd eth~xy ep6ilon-cdprolactone6; dnd cycloalkyl, aryl, and ardlkyl ep~i1011- CdprOldCtOlle6 ~UCIl as cyclohexyl, phel~yl ~nd benzyl epsiloll- cdprc~l~ct;olle~ .

, ";,.;.:
:-, ~

lg - 1 3 ~ 3 ~
.
Lacto~le6 ilaviny more thdll ~ix cdrbon atom~ tt riny, e.g., zeta-~uatholactone ~nd eta-caprylolactoll~ may ¦ al60 be polymerized in accorddnce Wi~tl the mettiod of t~l~
illve~ltioll .

2 5 (v) HYdroxY Furlctional 5~conddr~ Amir!~ RedCtd 2 T~le llydroxy functional 6~coIldary amill~ WhiCIl i~
reacted irl chaiJ~ termi~lating reactioll with th~ modifi~
diepoxide mdy be selecLed from a broad c1ds6 of d1i~hatic, cycloaliphatic and aromatic hydroxy unctollal amines.
Numerou~ ~uch dmine~ which may be~r mono- or di2lydroxy functiond1ity will be apparellt to those ~hilled in tlle art in view of the present disclosure. ~xemp1ary of 8uch amines are those having the for~ula (Il):

R - 0}1 1 5 HN ~ ~ 1 I ) \ R -X
' ' wherein R and R are selected from the group consi~tillg of aliptlatic, cycloa1iptlatic a~ld aromatic radic~1~ wllicll will IlOt iJIterfere Wit~l t~le Chdill t~rmitldtiOII rl!dcl;ioll bet.Weell ~ ctlain ex~elld~d diepoxide and ~ hydroxy func-iollal 6econdary amine. ~ alld ~ in the above formuld may b~ e same or different, but preferably shoula be of tll~ sdme nature. ~ may be 6elect~d from tlydrogell and bydroxy1 radical.
While ttle tlydroxyl group on a and/or R may be other than primary, primary hydroxyls are prefetred sillce 8UCtl primdry tlydroxy1 groups are more reactive (i.e., they react faster) Wittl the cros~1in~illg agent of th~
compo~ ion durilly curlng.

-- 20 _ 13~

Exanlples of preferred radical6 R and R' for tlle hydroxy functional amisle of the above formula (II) are:

(CH2)n where ~ 5;
~CH2CH20)nCH2cH2 w~ere n ~ 1-12;

S (CH2CH2CH2~H2cH2~-O)llcH2c 2 wbere ll , 1-12; alld C~3 (CH-CH2-O)I~CH2CH2 - where ~ . 1-12.

Preferably R alld R' are met~lylene, et~lylerle, or lower dlkylerle yroup6 but ~hey may be atly oth~r ~lozlillterf~ri~lg 10 radic~l includi~l~ tllose, for exampl~, ~uc~ a6 beTIzyl, oxyalkylene, etc.
Particularly prefer~ed primary hydroxyl beari~lg àmines for u6e irl preparing the ~Iydroxy func~iollal epoxy ester re6in precur60r are dietllallol amine, metbyle~lallol 15 amine, dipropanol amine, alld mettlylpropallol amille.
T~e modified diepoxide us~d to i~litiate lac~o polymerization in the prep~rdtiou of tlle epoxy e6ter re6in precur60r of the invelltiorl cal~ be made accordill~ to tech~lique~ well known to the 6killed of tlle art. The 20 chain exten6ion of t~le diepoxide, w~ere nece66ary~ i6 carried out fir~t by challging diepoxide alld diphellol iJltO
a suit~ble reactor drld tleatirlg tlle mix~ur~. Tlle reactallt~
~re u~ed in relative prvportiol~ to yield d Clldill exten~ioll reactioll product bearillg t~o unreac~ed epoxide groups a~ld preferdbly 6ub~tdlltially u~ uuredcted p~lellol fullctiolldlity. Suitdbl~ l3epdrdtioll t~C~ U~ dr~ kllow ~o t}le ~killed of t~le art for removdl of unused redct~
It ~bould be recogllized tbat to assure rapid dlld~or nlor~
comple~e reactivll of ttle diepoxide wi-tl t~e phellol dlld carboxyl functiollali~y, it i~ u~ually preferred to )IdV

~ :
' ~ `' ;` '` ~ ' ' ` ' .

21 ~3~
;i, catdly6t pr~6el1t. ~ use of Cdt~ly6t ~Id~ b~l1 found to provide ddval1tayeou6 epoxy ester re~i~1 of the il1Ve~1tio~1 ar1d is preferred. Epol1 829 (tradem~rk), mentiolled above, as sold, provide~ d proprietary cataly~. Epolr 828 5 ttrddemarh), i8 6ub~tdntially the same but doe~ IIOt provide suc11 cataly~t. Suitable cataly6t~ ar~
commercially available and include, any of the well kl1ow ~, cataly6t6 for epoxy-p~1énol and epoxy-dicarboxyl redctio uc~ as, for example, sodium carbollate, ethyl~ripl1e~1yl l0 p~osphonium iodide, lit~1ium neodecal1oate a~1d ott1er oryano metallic cataly6t~ and tertiary amines, ~uch a6 be~1zyl dimethylamine. Other ~uitable cataly6t~ will be dpparel1t to tho6e skilled in the art in view of tlle pre6ent di6clo6ure.
T~e reactiol1 mixture i8 heated to at lea6t dbout l40C (250F). Wbe~1 ill the pre6ence of CatalyBt, dll exot~1ermic reactiol1 will proceed Wit~l or without fur~ller ledtilly. TypiCdlly, tlle reactiol1 mixtur~ will ~h~ll redd about 149C-176C (300Y 350Y), depelldill~ u~on tlJe bdtcl~
8iZ~ ~lld r~actor ve66el il1sldtiolJ, ctc. Ill tll~ db6~rlc~ ~f catdly6t, 8UC~1 exotl1erm is typically IIOt ob~erved dnd coutinued heati~1g i~ r~quired. Th~ proyre66 of tlle reaction ca~l be followed by mea6uriIlg acid number measurement6 or weight per epoxide (WPE), i.e., epoxide equivalent weight.
A6 noted above, tlle dispoxide i~ reac~ed sub6tarltially simultaneou61y witll diphenol and ~ dicarboxylic acid ill amou~t6 6ufficiellt to yive d weig~1t i , per epoxide (WPE) of between about 500 al~d about 2,500, preferably be~weel1 about 500 al1d about 1,500. Preferably.
~; the acid aud di~hellol react~d witll t~1e diepoxide are employed ill a ratio of from dbout 10:90 to about 90:l0.
After comple~ion of ttle ct1ail1 ~xtell6ioJI of tl diepoxide, lac~one mollomers are polymerized ill tb~

- 22 - 13~ 3~

presence of the chain extended diepoxide to form the modified diepoxide. The lactone monomer6 and the combined diphenol and dicarboxylic acid are employed in a molar ratio of at lea~t about 2:1, re6pectively. Polymerization 5 of t~e lactone6 in accordance with this invention iB
carried out in conventional manner in that the polymerization i6 initiated by reaction with a compound having at lea~t one reactive hydrogen capable, wit~l or without the aid of a catalyst, of opening the lactorle rin~
10 and adding it a6 an open chain without forming water of condensation - in this in6tance the initiator compound being the chain extended diepoxide de6cribed above.
To initiate and continue tbe polymerization of the lactone, ttle lactolle and the initiator (i.e., the diphenol chain exte~lded diepoxide) are preferably heated to a temperature betweerl about 130 and 200C. ~JI order to achieve a practical and desirable rate of reaction with a minimum of decompo6ition. The temperature may be con6iderably lower however, i.e., a6 low as abDut 50C. at the sacrifice of ~peed of reaction. It may alsD be considerably higher, i.e., up to about 300C., although care must be taken at 6uch higher temperature6 because of the more likely 1066e6, at temperature~ above 250C., due ¦ to decompo~ition or unde6irable 6ide reactions.
I 25 Generally, therefore, a temperature range of 50 to 300C.
i6 con6idered operable and a more limited range between about 130 and 200C. i6 con6idered prefe able.
The polymerization may be, and preferably iB, carried out with the use of a catalyst, such a6 a ba~ic or neutral e6ter interchange cataly~t, to accelerate the reaction. Among cataly6t6 6uitable for tllis ~urpose are 6uch m~tal6 d6 lithium, ~odium, pota66ium, rubidium, ce6ium, ma~ne6ium, calcium, barium, 6trontiu~, zinc, aluminum, titanium, cobalt, germanium, tin, lead, ~ .~

. ,, , ''~

133~Q~

dntimony, ar6enic and cerium, a6 well as the alkoxide~
thereof. Additional suitable cataly6t~ are, by way of example, the carbonates of alkali- and al~aline eart~
metal~, zinc borate, lead borate, ZillC oxide, lead 5 6ilicate, lead arsenate, litharge. lead carbonate, anti~ony trioxide, yermanium dioxide, cerium trioxide, cobaltou6 ace~ate and dluminum isopropoxide. Catalyst coslcelltra~ion6 betweell about 0.001 and 0.5%, ba~d on tlle weiyht of the ~tartiny lactone6, are suitdble. The 10 prefer~d rdnye i6 from 0.01 to 0.2%.
After formatiorl of the modified epoxide, the hydroxy functiorlal 6econdary ~mine reactdnt i~ char~ed illtO th~ reactiotl v~el to form tll~ hydroxy functiolldl epoxy e6ter re6in precur~or. Ttlis redctioll iB eXOtll~rlniC
15 dnd drive6 it~elf to completion. As noted dbove, t~le modified diepoxid~ i6 re~c~ed with ~Iydroxy functioJIal 6eCOlldary amille ill Chdin termillEltill9 re~ction ill approximately 1 to 1 equivalent rd~io, i.e., d~proximdtely 1 to 1 e~uivalent ra~io of epoxide group6 to amine 20 yroup6. This ratio i6 de6irable since exce66 ~poxy could result in gelation of the reaction mixture, wllile exces~
amine remailliny in the reaction mixture could comyete wi~h lactone monomer6 duriny formation of tlle epoxy-polye~ter yraft copolymer. For thi~ rea~on, if exce~6 amine i6 used 25 duriny formation of the precursor, it 6hould preferdbly be removed prior to reaction of the precur60r with lactolle ~onomer 6 .
Lactolle mollomers are 6ub6equelltly poly~erized in the pr~ence of the hydroxy functiollal epoxy e6ter re6in ~recur60r, whereill t~le polymerizd~iotl reactioll mixture compri6e~ between dbout 10 alld about ~0 w~igh~ perc~nt of the aforemelltiolled precursor dnd between about 90 dnd ~bou~ 20 weight percellt lactolle monomer~ le polymerizdtion of the l~ctone monomer6 i~ carried out in d . ~ , :

1 3 3 ~

COrlVetltiOrlal malln~r d~ described dbov~ for polym~rizdtio~l of lactotle monvm~r~ i-l the pre6e~ce of ttl~ cS~ai}l ex-ended diepoxid~. In tlli~ in~tdllce how~ver th~ iuiti~tor comDound being the llydroxy functiorl~l ~poxy e~t~r resi 5 precur60r de6cribed above. The lactolle6 temperature conditions and cdtaly6t6 deRcribed dbove for lactorle polymerization in the pre~ence of tlle Csldi}l ex~ellded diepoxide are al60 sui~able for tlle polymerizdtiol~ of lactone monomer6 irl the pre6ence of the precur~or.
The llydroxy fullctiorlal epoxy polye6ter yraft polymeriza~ion products obtained in accordanc~ witS~ e inYention have molecular weight6 generally upward6 of aboût 2 000 and ureferably within tbe ra~lge of about 4 000 to about 20 000 althoug~l molecular Weig~tB b~low and 15 ~ub~t~ntidlly ~bov~ ~hiB raslge sre ob~ai~labl~ if desir~d.
~tley also have reactiYe terminal bydroxyl or cdrboxyl groups tbe number of reactive termindl group6 depe~ldiny UpO~I the functiondlity of the initidtor tlle illitid~or in tsli6 inv~lltioll beiny tlle Clldill exLend~d diepoxide dnd Llle 20 llydroxy functiolldl epoxy e6ter re6ill precur~or. Tlley ~re ¦ chdracterized by the pre~ence vf 6erie~ of inteccollllected 6ub~tdntially linear units or groups composed of cdrbon ~ydrogeïl dnd oxygell. Tbe iD-ercol~llected unit~ dre opelled lactolle re6iduè6 edch llavillg a termindl oxy yroup at Ull~
25 elld a carbonyl group d- the otller end an illtermediat~
c~ain of at lea6t five carbon atoms and at leas~ oue hydroyen substituellt orl the carbon atom in tSl~
intermediate cllai~l tllat i6 attached to the termindl oxy yroup. The oxy grouy of one lactone residue i6 CO~lneC~ed ~o the carbo~lyl group of an adjacellt lactone residue in t~e 6eries and the oxy yroup of tlle las~ lactolle re6idue in a 6eries iB collllected to a hydrogell to form a termindl hydroxyl yeoup d~ one end of the serie6.

.~
. ~

. Y'~

- 25- ~3~

B._ Cro~61inkislq Aqent T~e cro6slinkillg agent employed in the ~ovel 601Vellt ba6ed COd~ill9 composi~;ion6 of t21e invent-ioll co~lprise6 polyfunctiollal ~ydroxy-reactive crosslinking 5 agent selected, preferably, fronl aminoplast cro661înki~lg d~nts alld block~d polyi~ocydllat~ crosslill~illy aU~Ilt6.
Exemplary of the type6 of aminopld6t cro~6~ ing d9~n~
a~ld blocked polyi60cydlldte cro~slinkillg a~e2lt~ whictl mdy be employ~d in t~iB inve-ltion ~re tt~o~ di~los~d i-l U.S.
10 ~atelJt 4,476,625 issu~d October 9, 19~4 to Kord~m~llo~ ~ the in particular column 8, line 15 to column 13, line 50.

(d) Bloc~ed Polvi60cvarla~.;e Crosslinkillu Aaent lS ThoEe embodiment~ of solvent based coating , compo6ition6 of the inventioll employing blocked il polyisocyanate cro~61inking agents exllibit exceptiollal shelf stability even Wl~en corro6ion int~ibitiDg pigmellt6 BUCtl as zinc chromate are used in hiqtl collcentrdtioll6.
As used herein ~bloc~ed polyisocyanate~ medn6 dn isocyanate compound containing two or more isocyandte groups, all of wllictl have been reacted with a materidl llicll will pr~v~llt r~dctioll of th~ isocydndte group ~t room temp~ratur~ Witll COmpOUIId8 thdt COIIVentiOndlly redC1, 25 with 6UCIl group6, ~nd a- lea6t some of WtliCh will permiL
tlldt reactioll to occur at lligller (cure) temper~ures. ln ; ye;lerdl t~Je blocked polyisocyandt~ may be prepdred by reacting d BUf ficient qudntity of dn dCtiVe ~ydroyen containing blocking ayellt Wittl ~lle polyi60cyanate ~0 in6ure that no free isocyanate groups are pre6ent. ~t~e blocking agent may be represented by ~he formula ~H dnd ..
. .
: -,, ~ :

~ - 26 - 133~$Q~

may be 6elected from numerous material~ ereindfter ¦ discussed, which bear an active hydrogen.
¦ The proper proportion of blocked polyi60cydnate ¦ cros~linkirlg agent to graft copolymer will depe~ld, ilJ
¦ 5 part, UpOII th~ propertie~ de~ired in the COd-islg to b~
¦ yroduced and, in part, upon th~ d~slred cuse re~oll~ of l the coatiny compo6i~ion (wllicll will depend, in turn, upon ¦ the bakiny 6chedule to be u6ed in curing ~be COdtilly l compositiorl) and, in ~drt~ UpOII the de6ired 6~0rdye ¦ 10 6~ability of ~he compo6i~ion, tha~ iB, UpOII ~SI~ de6ir~d 1 6helf life. Accordinyly, the dmourlts of cro~slillher Lhd~
¦ cdn be u6ed with tSIe epoxy e6ter re~ill vdries con6iderably. Psef~rably ~he bloched polyisocyand~e cros61islkirl~ agen~ i6 included in compo6ition~ of ~he 15 islVellt;iOsl ill dmOUllt8 BUCII that UpOII deblocl~iny of ~he blocked i60cydnate group6 at tSIe cure temperature of the ¦ compo6ition, the cro6slinkiny agesl~ will provide b~twe~ll about O.S and abou~ 1.6, preferably between abou~ 0.~ and about 1.3, reactive i60cyalldte group6 pér hydLoxyl grou~
20 on the film forming graft copolymer of ttle coating Co~pO6itiOIl a6 de~cribed above. Numerou6 types of block~d polyi60cyallate are well known to tho6e of tlle art which ~ay be suitably used isl this invetltion. Selectiorl o sucb blocked polyi60cyanate8 for u6e in thi~ invell~ion 25 would be appar~nt to tho6e of ~lle art isl view of th~
pre6es~t di~clo6ure. Particularly ~uitable blocked ¦ polyi60cyanate~, Wslicll will be diccu66ed further Slereinafter, islclude blocked polymethylene polypll~nol isocyand~es, i60cyanurate riny contdi}liJIg block~d 30 polyi60cyasla~e6 asld certaill oligoe~ter modified bloched polyisocyandte~, all of which are de~cribed irl detail ir V.S. Paten~ 4,5976,259 to Kordomerl06 referenc~d ~bov~.
lsl th~ prepardtioll of tll~ block~d polyisocydlldt~
cro661inking agent, any 6uitable organic polyi60cyarldte : ~ :
~, - 27 - 13~

mdy be u6ed. ~epre6elltative examples are th~ ~liplldtic compound6, tbe cycloalkyle~le compoulld6, th~ aromdtic compound6, eubstituted aromatic compound~, triisocydlla~es, i te~rai~ocydnat~6, dnd polymeri2ed polyisocydnate~.
'i 5 Ill additio~l, the oryanic polyifiocyandte mdy be prepolyme~ detiv~d from ~ polyol i~lcluding ~oly~tller ~, polyol or polye6ter polyol, including polyetbers whicll are reacted with exce66 polyi~ocydrl~tes t~ form isocydïlate-termillated prepolymer6. The polyols mdy be 10 ~imple polyol6 such as glycole, e.g., etbylelle glycol alld propylene glycol, a~ well a6 otller polyole such a~
glycerol; trimethylolpropane, pentaerytllritol, and ~lle e, a~ well ae mono-etllers BUC)I ae diethylell~ ylycol, tripropylene ylycol alld the like dnd polyether~, i.e., 15 alkylene oxide condell6atee of tb~ abov~.
A particular clas6 of aro~atic polyisocydndte~
whicll may be employed in the novel ~olvent ba~ed coati~lg composition6 of the invention ace polymethylen~ polypb~nol isocyallate~ havi~lg the formula:

NCO r NCO NCO

--CH2~H
n wherein ~ equal~ 1 to 3. Such compounds, ~old uuder tbe ~ trademark "PAPI" by t~le Vpjohn C~lemical Company of ¦ 25 Kdlamazoo, Miclligan, ~ave proven to be particularly u~eful in com~o~itions of ttle inveution, resultilly in I compo6ition6 exllibiting de6irable toughliese iu ~lle final ! cured co~itin$.
¦ The active hydrogen contai~ lg bloc~ g ayeslt~
1 30 wbich are reac~ed witll the above de6cribed org?nic dii~ocydnatd~ may be ~elected from numeroud bloc~ y l ~

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

3~
agents which will be apparent to those skilled in this art.
R~ resentative of those blocking agents which are preferred are ~ose selected from the' group consisting of (i) aliphatic, cycloaliphatic and aromatic alkyl monoalcohols; (ii) hydroxyl amines; (iii) oximes; (iv) lactamsi and (v) triazoles.

In a preferred embodiment, the blocked polyisocyanate crosslinking agent is the reaction production of (A) the reaction product of (i) organic diisocyanate o represented by the formula: , OCN -- R - NCO
wherein R is selected from the group consisting of aliphatic, cycloaliphatic and aromatic radicals and combination thereof and wherein one of the isocyanate groups thereof is a more reactive isocyanate group than the other isocyanate group and (ii) sufficient active hydrogen containing blocking agent to react substantially all of said more reactive isocyanate group; and (B) sufficient polyol to react all of said other isocyanate group.

(i) Isocvanurate Rinc Containin~ Blocked Isocvanate Com~ounds In general, these blocked polyisocyanates may be formed by blocking isocyanurate ring containing polyisocyanates with the aforementioned blocking agent. These compounds may be formed by cyclotrimerization of difunctional isocyanates.
Usually the reaction does not stop in this stage and continues through the formation of polyfunctional oligomers or a mixture of such oligomers with a portion of the pure triLunctional polyisocyanate. Mixtures of trifunctional product ~d v~icus polyfunctional oliscmers are co~mercially availaDle.
A particular desirable blocked polyisocyanate c-~ssli~ .g agen~ is the blocke~ form of the pure trifunctional isccyanu-_~e reprec_nted by the following fo-mula: O
C

ll / \ O
B - C - r'N - R - r~ ~ - P~ C - B

C \ C
O \ / O
~

C ~ O
B

r'~
i ''~'i' ' .
.

_ 29 - 133~
.

~I w~erein R i6 selected from the group con6isting of aliptlatic cyclsalipha~ic and aromatic groups and combination6 theLeof a~ld B i8 t~e residue of a~ active ~ydrogell containiny blocking ayent. More specif ically 5 tlli~ compound is di6closed in United States Paten~ No.

4.4~1 633.

~ii) Oliqoe6ter Modified Blocked Polyisocvdslates i Still fur~ r particuldr blocked polyisocydlldte~
10 useful as cros61i~lhillg ayents in th~ solvellt bdsed CO~tilly composition of ttliS inventioll are oliyoe6ter modified blocked polyisocy~ndte6 prepared from ~ pdrticuldr clas~
3 of oligoester diol6 and triols. A first type of SUCII
3 oliyoester modified bloc~ed polyisocyallates is prepdred 15 from ory~ic dii60cyanates bearillg OJle i60Cydtldte grou~
more ~eactive ~ ll tlle otber witt~ ttle more reacti~e i~ocyanate first beiny bloc~ed Witll a blockillg ~yent alld ttle remaining i60cyaJIate qroup thell being reacted with hydroxyl functionality of an oligoester diol or tciol as 20 referred to above. The second type of oligoester ~odified blocked polyi60cyallate may be prepared by reacting oligoester diols from the aforemelltioned clafls of oligoe~ters with dll eXCeSB of orgallic diisocyallate so a6 to form an isocydndte ~erminated prepolymer followed by 25 bloching of tbe terminal isocyallate grou~ of ttle prepolymer with au dctive hydroyell co~ltainilly blockillg ayent. ~cl~ of the e mdteci~l6 is pdr-iculdrly useful in ttle compositions of the invention al~d produce6 findl cured ~ COdtin9 compositions ~xbibitillg out~tdnding flexibility.
I 30 Oligoesters of ttle type employed in tlle preoalatior~ of these ccobslirl~ing ~yent- ara deaoribea io . .: .

:
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_ 30 _ 133~0~

United State6 Patell~ No. 4,322,508 is~ued Macctl 30, 1982, The hydroxy functional oligoesters within the useful class of materials (i) have a number averaqe molecular weight (Mn) between about 150 and about 5 3000, preferably between about 230 and about l000, (ii) bear 2 or 3 hydroxyl groups per molecule, and (iii) are formed by an esterification reaction between a carboxylic acid and an epoxide.

(b~ Amino Cro6~ kinq Auent According to alternat~ve embodimeIlt6 of tlle invention, the Ilovel ~olvent ba6ed coatiny compo~itiona employ tlydroxy-reactive polyfunctioIlal aminopla6t cro~slinking agents. Ie will be recognized t~lat 15 compatible combinatioIls of 6uitable polyfunctional amiIlopla6t crosslinking ayent(6) aIId blocked polyisocyana~e cro~61inhin~ agent(6) dl60 Cdll be used.
Included Wit)liII ttle amiuopla6t cro~slillkiIly ayents suitabl~ for use in the coating composition dre numerou~
2G materidl6 whictl dre well known to tlle 6~illed of the dr~
illcluding, tor example, alkylat~ mel~miIl~ formaldellyd~
resin6 with one to about eight carboIl atoms iu tt~e al~yl mo~ty. Ot~er suitable aminopld6t cro6slin~ing ayents will be appdrent to t~e 6~illed of ~le ~r~ in view of 25 pr~6ent di~clo6ure. Many 6uch cro6slinking agellt~ are readily commercially available includillg, for example, tbe Re6imen~ (trddemack) 6erie6 availabl~ from Mon6dnto ' Compdny, St. Loui6. Mo., ttle mo~t preferred being Re6imelle j 717 (trademark). de6cribed as a low temperature cure mettlylated melamineformaldehyd~ re6iu.
In additio~l, suitable polyfunctional aminopla6t crossliukiny ayellt6 C~ll be prepared employil~y convelltiolldl techllique6. Accordingly. for exanlple, a lower al~dnol ,~

: . , ;`' ~ ~ ' 133~

6uoh a~ metllanol, ethallol, butanol, isobutanol, ~ i60propanol, `lexanol, 2-ethylhexallol or th~ like or a ¦ mixture of any of tl~em iB r~acted Wi~tl d melamin~
formdldetlyde. Preferred crosslinkitl~ agents ~f t~i6 typ~
S include butylated melamine formalde~lyd~ r~sin, met~ylated/butyldted formaldehyde re6il~ dnd poly~lhyl thOxymet~lyl m~ldmil~e re6ill i6 IIIOst preferr~d ill view of it6 relatively lower c06t re~dy commercial avdildbility, its low redctivity Witll ~ film formi ~ 10 ~raft copolymer of t~l~ itlVelltiOII d~ Vd~d cur~
I temper~ture6. ln tlli6 regdrd, preferr~d polyfuno~iolldl dmillOpld6t cro861inkirl~ ag~llt is 6Ub8tdlltidlly Ullr~dCt.iV~
~, Witll tlle grdft copolymer at or below dbou~ 60C. OLher ~ 6uit~ble aminoplast cros61inkill~ agent6 will be d~dren~
3 lS to the 6killed of the art in view of tlle pre6ent disclosure.
Tlle proper proportioll of polyfunctiolldl aminopla6t cro661illkillg agent to graft copolymer will depelld, irl part, UpOII tlle properties desired in th~
20 coeting to be produced and, io part, UpOII t2le desired cur~
re~ponse of the coating compo6ition (whicll ~ill depend, in turn UpOII the baking schedule int~nded for curiuy tlle coating compositioll) and, in part, upon tlle desired storage stability of tlle codtiJIg compo6ition, thdt is, 25 upon the desired shelf life. Accordingly, tlle dmoullt~ of graft copolymer that CdU be blended witll tlle crosslink~r to form codtillg com~o6i~iolls of Llle invell~ioll mdy be vdried collsiderdbly. Pr~ferdbly. ~le dmillOpld6t , cro~6~ kirlg agent is used in dmount6 of dbout 5t to dbou~
30 40~ by weiqht of tbe ~otal resin 601ids, more preferdbly about 20t to dbout 30t.

.-, .:

..
..

:~
:~ -~ 13~&~
~ - 32 -:~
C. Generdl Discu6~iosJ - Ot~er AsPect~ of Invesltion a~ld OCher ComPonen~s T~l~ coatiu~ conlpo6itio11s of t~le i11V~11t-iOI~ tldV~
been found to provide a cu'red coati~ haviny the S ddvantageou6 phy6ical properties de6cribed above over wide ra11ge of cure temperatures and a wide range of solid~
level6. ~ore specifically the coa-iny compo6itions i accordinu to preferred embodiment6 of t~e inventio1~ haYe been found to cure at temperdtures from as low as about lO 120C or le6s within about 15 minutes or le6s and yet to cure d-~d ~uffer llV 6i911ifiCallt 1066 of ddvanta~eou6 phy6ical properties at temperatures dS higb dS about Z00C
or more for period~ up to about 60 minute6 or more.
Co11sidered toyether Wit~l the 6torage 6tability of ~he lS coating composition it Cdll be readily recognized tlldt Lhe pr~s~l1t illvet1tio11 provid~B d 11ig11ly Big11ificd11t ddVdllCe ilJ
~be codtiny composition arL.
It will be wit~1in the 6kill of the drt ~u determine the proper volatile orya1~ic conte1l~ for d give 20 COdtill9 compo6ition of the inventio11 and for d giVell applicdtio1l. Preferred 801vent6 ~dVe reldtively low volatllity at temperatures appreciably below ~heir boiliug points 6uch th~t 60lve1lt evaporatio1l i6 low durillg s~ord~e al1d/or applicatio1l of tbe soating compositio1l to tbe substrate. A suitable 601ve~lt system may include for example tolue1~e methyl etbyl ketol1e i60butyl acetat~
xyle1~e cello601ve acetate acetone and a mixtur~ of any of them. Ot~er solvents which may be employed include te~pe11e6~ alipllatic a1~d aromatic 1~aphtha6 a1ld the l;k~.
Additiondl ~uitable ~olve~t~ are commercially availdble a~ld will be appar~lt to the skilled of the art in view uf '~ tlle present di~clo~ur~.

~, ~

.
~' ~':` ' ' .

~- _ 33 _ 1~3~

Any solvent allowed to remain in the cured coating should be inert so as to avoid adverse effects upon the cured 5 coating or upon another coating layer used in conjunction with it during the curing process or thereafter. Preferably, the ~ cured coating is substantially free of solvent.
3 Sufficient solvent is used to reduce the viscosity of the coating composition to a level suitable for application to 10 the substrate in the desired manner.
Obviously, in those cases where the composition is to be applied as a chip resistant primer the amount of solvent will be reduced so as to give a solids level of about 60 - 80~, especially 65 - 80%. Such higher solids materials are generally 15 applied using hot spray equipment.
Flow control agent(s), for example, polybutyl acrylate; wetting agent(s), for example, silicone; pigments;
pigment dispersants; corrosion inhibitors, for example, chromate pigments, numerous of all of which are known to the skilled of 20 the art, may be employed in the coating composition of the invention. In addition suitable reactive additives can be used, including, for example, low molecular weight diol flow control agents and reactive diluents.
Compositions of the invention, and in particular the 25 chip resistant primers of the invention, may also include anti-settling or anti-sagging agents to control the thixotropic properties of the composition. Exemplary of available materials suitable for this purpose are Dislon (trademark) 6900-20X
manufactured by Kusumoto Chemicals, Ltd., Yokyo, Japan and sold by King Industxies, Norwalk, CT. 06852; and Cab-O-Sil (trademark) ~-5, Cabot Corporation, Boston, ~ass :`''' ` ': ~ ' ;~ .
':' ' . , :
.
;~

- 13~Q~

Curing the coating compo6ition requires baking for 6uffici~nt time at sufficiently ~levated temperature to react the croG61inking ayerlt with ttle hydroxyl functionality of th~ llydroxy functiorlal epoxy-p.olye6ter S graft copolymer. The time and temperature reyuir~d to cur~ the coating are interreld~ed and depend upon tl particular hydroxy functional epoxy-polye6ter ~esin, cros61inking agent, solvent and other material6, if auy, and t~e amount of each compri~ing the coatiny 10 compo6ition. The coating compo6ition~ according to preferred embodiments of the invention, as de6cribed above, have been found to provide the be6t coating result6 when cured at temperature at about 150C (300F) for 20 minutes. lt is a highly 6ignificant advantage of the 15 invention, bowever, ~hat the6e same coating compo6itiorl6 can with6tand, for example, temperature a~ hig21 as about 200C t390F) for period~ of time as long as about 60 minutes. Accordiugly, great flexibility iB provid~d in botll designing dlld implementing a curing 6ch~dule f~r 20 part6 coated witll tll~ coatillg compositioll6 of tll~
I invention. Tllu6, in tll~ a66~mbly of automotiv~ v~bicle6, for example, vehicle6 unavoidably held in a curiny o~en for long periods of time during unplanned a66embly line ~llut-down~ are recover~d Witll cured and unharm~d coatings.
Hiyh ~olid6 coatin~ compositions according to the , pre6ent invention, comprisiny tbe novel crosslinkabl~
I llydeoxy functiollal epoxy--polye~ter graft copolymer re6i I of the invention, e6pecially the preferred resin~
de6cribed above and blocked polyi60cyanate cro661inking 30 agent, e~pecially the preferred materials de6cribed above, have been found to afford cured coatings witb improv~d corro6ion re~istance and chip resistance, thus repre~ellting a ~lighly advantageou~ advance in tbe art.

:~
. . . .
, : .
, .

-` 1 3 3 ~ ~ 3 ~3 _ 35 -A mo6t p~eferred u6e of tl~e codting compo6itio of tbe inven~ion i6 a~ a ~iy~ solid6 hot 6prayable chi~
ce6i6~ant pcimer for u~e on a bare metal ~ub6~rate ~uch db for an automotive vellicle body which iB BUbjeCt to 5 chipping. Primer compo6ition6 typically are piymented a~d any pigment6 commonly included in primer compo6itiona or mecdl ~ub~trate~ and acrylic diapersion topcoats 6UC~ a6, for example, c~rbon black, ~ron oxide, llthopolle, magne6iual, ~ilicate, silica, barium 6ulfate, 1'iO2, chrome 10 yello~, calciu~ chromate, ~trontiunl chr~mdte, Zirlc p~tas~ium ctlronlate arly tlle li~e may be used. The primer cau be pigmented accordi~g to ~nowl~ methods il~cludiny, for example, by grinding pigment6 in a portion of tlle curable resin and dddill~ to the primer composition.
The piynlent-to-billder ratio of the chip re6i6tant primer may be rom about 0.5:1 to about 2:1 by weigh~, re6pecti~ely; it iB preerred, ho~evet, to u8e a primer having a pigment-to-binder ratio of fro~ about 1 :1 to about 1.5 : 1 by weiyht, re6pectively.
ln prefe~red embodimen~6 of ~is iilventiot-pig~ents and thixotropic a~ent~ desireably are di6persed wit~ epoxy e~ter re6ins whic~ do not have an elastomeric component as doe~ the hydroxy functional epoxy-polyester ~ yraft copolymer employed a~ the primary fil~ formin~ re6i~
¦ 25 of ttle composition6. 1- lla6 been found tbat in additio i to beill~ very effectice di~persing dyetlts for tlle 3 preparatioll of pigment millba6e6 d-~d thixotropic di6p~rsion6, non-ela6tomeric epoxie~ e t~le compositio toughne66. One type of epoxy useul for thi6 pur~o6e ` 30 conlpri6e~ tlle reactio~l product of diepoxide, dimer dcid and ~ mixture of Soya fatty acid dnd propio~lic aeid (See kxa~ple 6). Other epox~ e~ter re6in~ u6eful for tlli6 purpo-e are tbo~ di-olo-ed ill United States ratent ,~

! i, ~ ,~:
~ ~' ` ' '`~ - .

~;~

- 36 ~3~

No. 4,491,641, assigned to the ~ssignee of thi6 application. T~e6e res~n~ compri6e t~le - simultaneous reaction product of diepoxide ~it~
S dip~enol, dicarboxylic acid or a mixture of them in chain extension reaetion and (ii) fatty acid in c~aiu terminating e~terification reaction. Still ot~er ~uitable epoxy re6in6 u6eful for dispersing pigment a~ld ~hixotrop~c agent6 will be apparent to the ~killed of the art in vie~
10 of ttle pre~e~lt disclosure.
~ o 6pecial expedients are nece66ary in formulating t~e primer compo6ition6 of tbi~ iuventiorl.
~or example, they may be prepared ~imply by lncorpordtiJIy the resinou6 component6 in a 6uitable 601vent sy6tem.
15 T~lu6, for example, by 6uitable mixing or ayitation, eac~
re6inou~ component may be di6solved in a ~olvent arld tb~
re~ultil~g 601ut~0ns combine~ to form f~ni~hed p~i~er CompoGition~ .
The 601vent 6y~tem may be any 6uitable 20 combination of oryanic 601vent~ as described abov~. For a hiy~ 601ia6, ~ot 6prayable, automotive vehicle c~ip re6i6t~nt primer, tbe 601vent will compri6e preferably about 20 to about 40 percent by weiy~t of tbe t~tal coating compo6ition6, ~lt~ougb of cour6e, larqer or 25 6malle~ amount6 may be utilized depending upon tbe 601it~
content de~ired.
The primer i6 generally n~aintained at about 65 ~o about 80 percent 601~d6 content for hot spraying purpose~
~ith conventional thinner6 6UC~I aB aromatic ~ydrGcarbon6, 30 commercial petroleum CUt6 WbiCtl are e~6en~ially ar~ma~ic, and the like, ~nd 6prayed OlltO tbe metal ba~ or otber 6ub6trate dlld cured. Sbe primer ~ay be ~ppli~d ill yreater tllic~ne66 of 1 to 25 ~ils wet, ereferably 10 to 25 mil6 wet, in order to obtdiJI final ~oating~ in tlle de6ired , .

..
.
.

. ~ , ~: . . - ,. . .

1 ~ 3 ~

f ranye of S-ll mils in regiotl6 hig~lly 6usceptible to cbipping and i~ tben featbered down in thic~ne6s to t~
thicknes6 of paint6 ifl area~ nvt receiving a c~ip resistdnt primer. The primer i6 cured at elev~ted 5 temperdtures by dny convenient means such as bahing OV~IIS
or bank6 of infra-red heat lamps. Curing temperdture6 dre preferably from about 135C to about 165~C, altlloug~
curing temperature6 from about 100C to about 230DC may be e~ployed, if desired.
The invention will be furt~ler under6~00d by referring to the following detailed example6. It ~hould be understood that the specific examples are presented by way of illu6tration and not by Wdy of limitation. Unles~
otherwi6e specified, all references to "parts" are lS intended to mean parts by weight.

.~

E

1 3 ~
- 3~ -Exampl e 1 PrePacation of EPoxv-PolYester Graft Co~olYmer Into a suitable reactor were charged 392 parts Epon 829 (trademark), Shell Chemieal Co., diepoxide, 46 5 part6 bi6p~enol A, 70 part~ dodecanedioic acid and 220 part6 Solveeso 150. Tbe temperature of this mixture wa~
brought up to about 150C-160C. After one hour the acid number wa6 found to be 1.5. 1~6 part~ of epsilon-caprolactone and 0.2 part6 of dibutyl tin oxide 10 wa~ added to the mixture and the temperature wa6 kept at 160C for one hour. 104 part6 diethanolamine wa6 added to the mixture. After one hour at 150C, 434 parts of ep6ilon-caprolactol~e and 1 part of dibutyl tin oxide wa6 charged. The temperature wa6 raised to about 160C for two hour6. At t~is point heating wa~ terminat~d ~nd 310 parts M-pyrol was added. The resultillg reffirl }Idd d Y
viscosity at 70% 601id~.

Exam~lf 2 PreParation of EDoxv-PolYe6ter Graft CoPolYmer ~0 Into a 6uitable reactor were charyed 294 part6 Epon 829 ~trademark, Shell Chemical Co., diepoxide), 46 parts bi6phenol A, 17Z part~ Empol 1016 (trademark, Emery lnd., Inc., dimer acid) and 220 part6 Solves60 150. The temperature of the mixture was brouyht up to 150-160C.
~25 After one hour at this temperature, the acid uumber was ¦fOUrld to be 1.8. 169 part~ of ep~ilon-caprolactorl~ ~nd 0.2 parts of dibutyl tin oxide were added to the mixtur~
and the temperature wa~ kept at 160C for two l~ourff. It was then cooled to 130C ~nd 52 parts diethanoldmill~ ar~
added _ 39 _ 133~

to the mixtu~e. After one hour at 150C, 395 part6 ep6ilon-caprolactone dnd 1 part of dibutyl titl oxide were charged. The temperature wa~ raised to about 160C and maintained for two ~lours. At tlli6 point heating WdB
5 terminated and 265 parts M-pyrol were added and the mixture was allowéd to cool. The resin had a Z visco~ity at 70t solid~.

ExamPle 3 PreParation of EpoxY-Polyecter Graft Copolvmer Into a suitable reactor are charged 530 part6 Epon 329 (tcademark, Shell Chemical Co., diepoxide), 46 part6 bi6phenol-A and 230 part6 Empol 1016 (trademark, Emery Ind., Inc., dimer acid) and 320 parts Solve660 150.
The temperature of the mixture i6 brought up to 160C.
15 After one hour at this tempe~ature, the acid number i6 found to be zero. 330 part6 of ep6ilon-caprolactone and 0.1 parts of dibutyl tin oxide are added to the mixture arld the temperature i6 kept at 160C for two hourfi. It i~
t~en cooled to 130C and 46.5 part~ N-methylethanolamine 20 are added to the mixture and t~le temperature i~ raised to about 150C. After one hour 6~0 parts epsilou-caprolactone and 1 part of dibutyl tin oxide are added to the mixture and the temperature i6 rai~ed to 160C. At thi6 point, héating i6 termina~ed and 400 part~ M-pyrol 25 are added and the mixture i6 allowed to cool. The resin hafi a vi6c06ity of Z5 ~t 70% solids.

'i. ' `: ~ .

1 3 ~

Ex~mPle 4 PreP~rdtiosl of EDoxY-PolYe~ter Graf~ CoPolym~r Into a suitable reactor ar~ charg~d 519 part6 of Epon ~29 (trademark, Shell Chemical Co., di~poxide), 101 part6 of bisp~enol A, 254 part6 of Empol 1016 (trad~mark, Emery I~ld., Inc., dimer acid) dIld 235 part6 Solve6~0 100.
The temperature of th~ mixture i~ brou~tlt up to about 160C. After one hour at thi~ temperature, tlle ~cid number is found to be zero. 470 parts of ep~ilon-cdproldctone and 0.2 part6 dibutyl tin oxide ~re added and ttle temperature i~ kept at 160C for two hour6.
It i6 thell cooled to 130C ~nd 69 parts N-methyletbanolanlisle are added dnd t~le temp~ratur~ i~
¦ rdised to dbout 150C. After one hour, 944 pdrt6 ¦ 15 ep6ilon-caprolactone and 2 parts dibutyl tin oxide are ~dded to the mixture dnd the temperatur~ i6 rais~d to 160C dnd mdilltdined for one hour. At thi6 pOitl~ heatill~
i6 termi~lated and 755 part6 M-pyrol dre ddded drld t~le mixtur~ llow~d to cool. T~l~ resill ~ d Z3 20 visco6ity at 70% solid~.

ExamPle S

I Pre~aratiorl of_Epox~-Polye6ter Graft CoPolvm~r ~ Into a 6uitable reactor are ctlarged 350 part6 3 ' Epon 829 (trademark, Shell Chemical Co., diepoxid~), 56 ¦; 25 part6 of azelaic acid, 68 parts bi~phellol A and 200 p~rt6 Solves~ 100. The temperature of t~e mixture is brou~l~t up to about 160C; after one hour at this temperature, the ~` aoid rlumber i6 fourld t~ be zero. 396 parts of ep6ilon-caprolactone dI~d 0.2 part6 of dibutyl till oxid~ ;
~, '.

t ;` '~

- ql 133~

are added and the temperature i~ kept d~ 160C Lor two ~lour6. It i6 then cool~d to 130C and 60 pdrts of Solve~60 100 and 46.5 part6 of N-methylethanoldmille are added to the mixture and the temperature i~ rai~ed to 5 about 150C. ~fter one hour 793 part6 of epsilon-caprolactone atld 2 palts of dibutyl till vxide are added to t~le mixture and the temperdture i~ rdi~ed to 160C and maitltairled for one hour. At thiE pOi~lt lled~itly iB di6continued dnd 480 part6 of M-pyrol are added. Tlle 10 re~in lla6 a Z vi6c06ity at 70% 601id~.

Examvle 6 Pre~drdtioll of E~oxY Ester Dis~er~in~ Re~in IIJto a 6uitdblY reactor were charg~d 12~0 pdr~
E~oll 829 (trddemark, Sh~ll C~l~micdl Co., diepoxide), 954 15 part6 Empol 1016 (trademarh, Emery Indus~ries, dimer acid), 364 ~arts Soya fatty acid, 265 part6 2,2 bis(hydroxymethyl~propiollic dcid, dnd 13 par~ litllium neodeconoate. The t~mpera~ure of the mixtur~ Wd6 b up to about 180C, at WhiCIl point an exothermic reactio 20 took place that rai6ed the temperature to about 200C.
After one hour, tlle acid number wa6 found to be le6~ thdrl 2. 940 part6 Solves60 100 and 305 part6 Solve~so 150 were added, and the mixture wa~ cooled. The reBin lldd d vi6co~ity of Z7 at 70t 601id6.

Example 7 PreDaration of Bloched Polvi~ocvalldte Cro~61inkin~ A~en~

¦ Into a ~uitable reactor were charged 537 pdrt~
¦ t~etllylethyl ketoxime. 754 part6 PAPI 94 (trademdrh, ~ _ , ,~, :'-:
. ~
~ ~ `

~; `

q 2 ~L 3 ~ 3 1~

UpJoh~l C~lemical Co., droma~ic polyi~ocyandt~) Wd~ add~d dropwi~e over two tlour6; th~ r~action temperdture ro6e from room t~mperatur~ ~o 80C-95C. T~ emp~ratur~ of the mixture Wd6 mailltairl~d dt 85C-95C for osle:llour.
5 Af~er 30 minute~, the mixtur~ was ~h~ck~d to insur~
j comple~e reaction of i~o~yandt~ by infrdr~d. At t~ld~
pOitl~, 300 par~6 methylamyl ketolle and 150 part~ M-pyrol were added dnd the mixture wa6 cooled. The resulti resin wa6 dark brown alld and wa~ 75% 601ids.

! 10 ExamPle B

PreParation of ~locked Polvi60cvarlte Cro~61inkirla AuenL

i Into a 6uitable reactor ar~ charged 870 par~
methylethyl ketoximY and 180 part6 Solve660 100. 1330 par~6 of ~API 27 (trademark, UpJohn Chemical Co., aroma~ic 5 pQlyi60Cydndte) i6 added dropwi6~ to the mixture over two hour6; the r~actiorl t~nlp~rdtur~ ro~ from room temp~ratur~
`i ~o B5C-95C. 39 part6 2-e~hyl~heXdllOl i8 ddd~d ~O ~h~
,~j mixtur~ ~nd t~l~ t~mp~ratur~ of ~ mixtur~ i~ mailJtdill~d Y a~ 55C-95C for o-l~ tlour. At tha~ point, 616 part~ of 20 M-pyrol are add~d and tbe mixtur~ i~ cooled. Tll~
re6ultil~y re6in i~ dark brown and has a visco~ity of 6000 Cp8 at 75.0S ~olid~.

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_ 43 _ 133~Q~

ExamDles 9-12 PreParatio- of Blocked Polvi~ocvanate Cros~linkinq Aqent Blocked isocyanate cro661inkers accordillg to the invention were prepared in the manner of Example 8. The component~ employed are shown in the table below.

j Exam~le 9 10 11 12 ComDo6itio~ Part~
L-2991 A~ 360 360 360 Desmodur IL* 525 10 methylethyl ketoxime 174 87 benzotriazole 238 epsilon-caprolactam 227 N-metllyl pyrolidone 133 150195 461 % 601ids 80 80.1 75.157 15 Vi6cosity Zl Z6 Z2 Z

: ~Trademarks of Mobay Chemical Co.; L-2291 A is a biurette ~ of hexamethylene dii60cyanate; De6modur IL i6 a ¦~ polyisocy-nurat- of tolrlene dii~ocyanat-.

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ExdmDle 13 Millbase PreDaration In a one galloll c~n or ballmill were c~larged th~
following materials and one qua~t of dia~onal ~hot. The 5 mixture was placed on a roller mill for 16 - 24 hour6 to reach a 7~ hegman disper6ion. At that point, the letdowr wafi added, and the mixture was run an additional hour on the roller mill.

Hi-Sol ~3~ 585 2-Ethyl Hexanol 95 PolyethyleIIe Wax 70 Anti--Terra-U~* 40 ! Resill of Example 6 103 ~ Barytes 2259 ¦ 15 Tio2 429 Cdrboll Bl~ck 29 Strontium Cll~omate 143 Letdown: Resi~ of Example 6 247 ~ Trademark of Afihland Chemical Co., Colunlbu6, 20 Ohio; Hi-Sol #3 i6 an aromatic solvent.
~~Trademark of Byk Mallinckrodt, ~allingford, CT
¦06492; Anti-Terra-U i6 an anti6ettling and we~ting agent.
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_ 45 -¦ ExamPle 14 Bentone Gel PreDaration:

To a clean Ball Mill, charge the followiny:

Part6 Solvesso 150 513 Propylene Carbonate 13 Bentone 38 30 G~ d 30 mi~lute~, thell ddd:
Resin of Example 6 3a4 10 Grind approximately 2 Hr6. to ~ HegmaJI.

Letdown with:
Hi-Sol #3 60 ExamPle6 15-20 Coatin~ compo6itions of tbe inventioll dL~
for~ulated a6 shown in Table A. ~e coatin~ compo~ition6 are prepared by sequential mixing in a 5 gallon workin~
capacity EMC0 Proto-Lab SW Mill (trademark), ~pworth Mfg.
Co., Soutll Haven. Mich., 6et at 900 rpm. Re6i~ and Dislo~
20 (trad~mark) are firs~ mixed for approximately 10 mi~lute~
andthen millbase, Bentone gel and crosslinker are ~dded seyuentidlly while mixi~g. Finally Cab-0-Sil ~trademdrk) is added and the composition mix~d until a gring of 6~ or ~he Heyman Scale wa6 obtained.

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T~le above composition6 are ~prayed dL 60-70~C
usirly bot-sprdy e~uipment commercidlly available from Nordsoll Corp. Unpoli6hed B~nderite steel pdn~ls ar~
sprdyed ~nd baked dt 135DC for 20 minutes. Tll~ thicklles6 5 of the cured coating tested varied from 5 mils to 12 mi16. The panel6 are top-coated with white enamel dnd te6ted for chip resistallCe u8iny 10 ptB. of gravel in the gravelo~eter test. In addition, ~anel6 ar~ t~6ted f~r corrosion re6istance (500 hr~. salt spray test, scribed 10 pan~ nd l~1dity re-i-tdnc~.

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Examples 21-24 Additiondl coating compo6ition6 accoLdislg to the invention aré 6hOWIi in Table 8.

Table ~
5 ComDosition Examvle 21 22 _ 23 24 Re6in of Example 42141 21412141 2141 Millba6e of Example 13 57885788 5788 578~
Gel of Exampl~ 142315 23152315 Z315 Cros61inhor of Example 9 922 10 Cro661inker of Example 10 922 Cros61in~er of Example 11 984 Cro~61inker of Example 12 1294 Di610n* 100 100100 100 ~Trademdrk ~u~umoto Cllemical6, Ltd., Di610rl i~ all 15 anti-6aggilly agerl~.
~*Tradem~Lk of Cabot Corp., BOBtOn, mas6., Cab O-sil i~ a fo~med 6ilica (aDti- 6ettliU9 ager~

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In view of this disclosure, many modifications of this invention will be apparent to those skilled in the art. It is intended that all such apparent modifications fall within the true scope of this invention and be included within the terms of the appended claims.

Industrial AD~lication It will be apparent from the foregoing that this invention has industrial applicability as a coating composition, especially as a hot sprayable, high solids coating composition suitable for use as a chip resistant ~ automotive vehicle primer adapted for use on a body panel ¦ areas subject to chipping by stones, gravel and other road debris.

This application is a division of Application No.
549,041, filed 1987 October 19.

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Claims (17)

1. An organic solvent based, thermosetting coating composition comprising:
(I) a hydroxy functional epoxy-polyester graft copolymer suitable for use in a thermosetting composition, which copolymer has a number average molecular weight (M?) of between about 2,000 and about 20,000, said copolymer being the product of polymerization of lactone monomers in the presence of hydroxy functional epoxy ester resin precursor having reactive hydroxyl groups, said lactone monomers being polymerized and reacted with hydroxyl groups of the precursor without chain extension of the precursor to form pendent hydroxyl terminated polymer chains, wherein the polymerization reaction mixture comprises between about 10 and about 80 weight percent said hydroxy functional epoxy ester resin precursor and between about 90 and about 20 weight percent said lactone monomers, said precursor being the reaction product of:
(i) modified diepoxide being the product of polymerization of lactone monomers in the presence of diepoxide which has been chain extended substantially simultaneously with diphenol and dicarboxylic acid, said diepoxide being reacted substantially simultaneously with said diphenol and dicarboxylic acid in amounts sufficient to give a weight per epoxide of between about 500 and about 2,500, wherein said lactone monomers reacted to form said modified diepoxide and the combined said diphenol and dicarboxylic acid are employed in a molecular ratio of at least about 2:1, respectively;
and (ii) hydroxy functional secondary amine in chain termination reaction in about 1:1 equivalent ratio;
and (II) polyfunctional, hydroxy-reactive crosslinking agent.

2. A solvent based, thermosetting coating composition in accordance with claim 1, wherein said diepoxide is selected from the group consisting of bisphenol-A epichlorohydrin epoxy resin, hydantoin epoxy resin, cyclic and acyclic aliphatic diepoxides and mixtures thereof.

3. A solvent based, thermosetting coating composition in accordance with claim 1, wherein said diphenol is selected from the group consisting of bisphenol-A, bisphenol-B, bisphenol-F
and mixtures thereof.

4. A solvent based, thermosetting coating composition in accordance with claim 1, wherein said dicarboxylic acid is selected from the group consisting of saturated or unsaturated, cyclic or acyclic, aliphatic or aromatic dicarboxylic acids and mixtures thereof.

5. A solvent based, thermosetting coating composition in accordance with claim 1, wherein said dicarboxylic acid is selected from the group consisting of saturated, acyclic, aliphatic dimer acids of about 4-42 carbons.

6. A solvent based, thermosetting coating composition in accordance with claim 1, wherein said hydroxy functional secondary amine has the general formula:

wherein R and R1 are selected from aliphatic cycloaliphatic and aromatic radicals which will not interfere with the chain termination reaction of said modified diepoxide and said hydroxy functional secondary amine to form said hydroxy functional epoxy ester resin precursor, and wherein X is selected from the group consisting of hydrogen and hydroxy radical.

7. A solvent based, thermosetting coating composition in accordance with claim 6, wherein said hydroxy functional secondary amine bears primary hydroxyl functionality.

8. A solvent based, thermosetting coating composition in accordance with claim 7, wherein said hydroxy functional secondary amine is selected from the group consisting of diethanol amine, methylethanol amine, dipropanol amine and methylpropanol amine.

9. A solvent based, thermosetting coating composition in accordance with claim 1, wherein said lactone monomers are selected from those represented by the general formula:
wherein n is at least 4, at least n + 2 R's are H and the remaining R's are substituents selected from the group consisting of alkyl, cycloalkyl, alkoxy and single ring aromatic hydrocarbon radicals.

10. A solvent based, thermosetting coating composition in accordance with claim 9, wherein said lactone monomers comprise unsubstituted epsilon-caprolactone.

11. A solvent based, thermosetting coating composition in accordance with claim 1, wherein said crosslinking agent comprises blocked polyisocyanate crosslinking agent comprising at least two isocyanate groups which have been blocked by reaction with an active hydrogen bearing blocking agent, said blocked polyisocyanate crosslinking agent being included in an amount such that upon de-blocking of the blocked isocyanate group thereof at the cure temperature of the composition, said crosslinking agent provides between about 0.5 and about 1.6 reactive isocyanate groups per hydroxy group on said hydroxy functional epoxy polyester graft copolymer.

12. A solvent based, thermosetting coating composition in accordance with claim 11, wherein said crosslinking agent consists essentially of blocked polyisocyanate consisting of blocked aliphatic, aromatic, aliphatic aromatic and nuclear substituted aromatic polyisocyanates and compatible mixtures thereof.

13. A solvent based, thermosetting coating composition in accordance with claim 11, wherein said blocked polyisocyanate crosslinking agent comprises blocked polymethylene polyphenol isocyanate which prior to blocking has the formula:

wherein n equals 1 to 3.

14. A solvent based, thermosetting coating composition in accordance with claim 11, wherein said blocked polyisocyanate crosslinking agent is the reaction product of (A) the reaction product of (i) organic diisocyanate represented by the formula:
OCN -- R - NCO
wherein R is selected from the group consisting of aliphatic, cycloaliphatic and aromatic radicals and combinations thereof and wherein one of the isocyanate groups thereof is a more reactive isocyanate group than the other isocyanate group and (ii) sufficient active hydrogen containing blocking agent to react substantially all of said more reactive isocyanate group; and (B) sufficient polyol to react all of said other isocyanate group.

15. A solvent based, thermosetting coating composition in accordance with claim 1, wherein said crosslinking agent comprises aminoplast crosslinking agent being included in an amount between about 5% to about 40% by weight of the total resin solids.

16. A solvent based, thermosetting coating composition in accordance with claim 1, adapted to be used as a chip resistant primer to be sprayed at elevated temperature, wherein the solids level of the composition is in the range of 60-80% by weight.

17. An organic solvent based, thermosetting coating composition comprising:
(I) a hydroxy functional epoxy-polyester graft copolymer suitable for use in a thermosetting composition, which copolymer has a number average molecular weight (M?) of between about 2,000 and about 20,000, said copolymer being the product of polymerization of lactone monomers in the presence of hydroxy functional epoxy ester resin precursor having reactive hydroxyl groups, said lactone monomers being polymerized and reacted with hydroxyl groups of the precursor without chain extension of the precursor to form pendent hydroxyl terminated polymer chains, wherein the polymerization reaction mixture comprises between about 10 and about 80 weight percent said hydroxy functional epoxy ester resin precursor and between about 90 and about 20 weight percent said lactone monomers, said precursor being the reaction product of:
(i) modified diepoxide being the product of polymerization of epsilon-caprolactone monomers in the presence of the reaction product of (a) diepoxide selected from the group consisting of bisphenol-A epicholorohydrin epoxy resin, hydantoin epoxy resin, cyclic and acyclic aliphatic diepoxide and mixtures thereof, (b) diphenol selected from bisphenol-A, bisphenol-B, and bisphenol-F, and (c) dicarboxylic acid consisting of saturated, aliphatic, acyclic dimer acids of 4-42 carbons and mixtures thereof, said diepoxide being reacted substantially simultaneously with said diphenol and dicarboxylic acid in amounts sufficient to give a weight per epoxide of between about 500 and about 2,500, wherein said epsilon-caprolactone monomers reacted to form said modified diepoxide and the combined said diphenol and dicarboxylic acid are employed in molar ratio of at least 2:1, respectively; and (ii) hydroxy functional secondary amine bearing primary hydroxyl groups in chain termination reaction in about 1:1 equivalent ratio: and II. polyfunctional, hydroxy-reactive crosslinking agent selected from blocked polyisocyanate crosslinking agent comprising at least two isocyanate groups which have been blocked by reaction with an active hydrogen bearing blocking agent and aminoplast crosslinking agent.