Note: Descriptions are shown in the official language in which they were submitted.
WO g3/04104 ~ PCr/US92/07234
.
INTERNALLY FLEXIBILIZED ADVANCED EPOXY RESIN COMPOSITIONS AND COATINGS i~
TH E REFROM
The invention relates to internally flexibilized advanced epoxy resin compositions ::
5 flexibilized with in~ernal poiybutylene glycol units, and a process for the preparalion o~ such
internally flexibilized advanced epoxy resins. The invention further relates to coatings pre~ared
from such internally flexibilized advanced epoxy resi ns, such coatlngs are useful in cathodic ~ -
electrodepositions, powdercoating applications, marine and maintenance and in ;ood and ;
beverage applications.
' ``~
Advanced epaxy resin compositions are used in a ~/ariety of applications, such as in ~;
coatings compositions in several fields, for example in cathodic electrodeposition, powder
coating of pipes and structural elements, in liquid coating compositions for food and beverage
cans and marine and maintenance applications. AdYanced epoxy resin based coatmgs have .
15 advantageous properties such as adhesiveness, strength, hardness and chemical resistance
Unfortunately, cured advanced epoxy resin compositions suffer from a I ack of flexibility, which
can have 3 negative effect on other pro~erties such as protection of substrates from corrosion.
A representative use of advanced epoxy resins compositions which exhibits such
20 proolems is the field of cathodic electrodeposition. Cathodic electrodeposition of a film
composed of an amine modified eooxy resin, crosslinker, plgment ana ootionally other
reslnous componerlts onto an eiectrically conductive article is an imDortant Industrlal orocess. 't
constltutes :he usual manner n which automoblle and truck bodies as well as aDpiiance and
other !arge cor~plex rnetallic sur,ace bodies are protec~ed against corroslon. 'n Der;ormlr~g the
25 e!ectroaeooslt on, ~he conclucll~e artlc,e. a~ucle to be coate~. forms on~ electroae anc~ is
rnrnersed :n a coatlng Datn ~nade from an aaueous disr~erslon ot tne fii~ formmg amlne
modifiea epoxy ~esln and otner comDonerts. ~r elec~rlcal current IS Dasserd be~ween t~e arucle
and ~he counterelectrocle In he electrodeposlllc)n oath. A charge on ~he article causes
deposl;;or, o~ e res,ns and otner comporents m tne oatn on the article o be coatecl so as to
WO 93/04104 ~ 7 9 ~i PCr/US92107 ~34
produce the electrodeposited fiim. The de~oslted film is then baked or otherwise hardened to
yield a coating of a substantially uniform thlckness and protective characteristics -~
:' . '
A number of advances in the protective properties of electrodeposit resln systems
have been described in the patent literature. For example, US Patent Nos. 4,104,147; 4,148,772;
4,420,574; 4,423,166; 3,962,165; 4,071,428; 4,101,468; ~,134,816; 3,799,854; 3,824,111;
3,922,253; 3,925,180; 3,947,338; 3,947,339, describe methods for improvement of the principal
resin properties. Amine modified epoxy resins used in the coatings disclosed in these patents ~;
can be flexibilized by extending the molecular length of the aromatic diepoxide starting
10 material with polyols, polyamines, polyether polyols, polyester polyols and other similar types
of extension agents. US Patent 3,839,252 describes modification with Dolypropylene glycol. US
Patent 3,947,339 teaches mc dification with polyesterdiols or polytetramethylene glycols. US .
Patent4,419,467describesstillanothermodifi~ationwithdiolsderivedfronncyclicpolyols ;~
reacted with ethylene oxide. In those embodiments wherein polyether polyols and polyester ~ ~-
15 polyo~s have been used to modify the advanced epoxy resins, it has been difficult to efficiently
and effectively incorporate such materials into the backbone of the resin. Tertiary amines or
strong bases are required to effect the reaction between the primary aicohols and the epoxy ;~ ~`
groups involved. Furthermore, these reactions require long cook times and are subject to ; ~: -
gellation because of competitive polymeri~ation of the epoxy groups by the base catalyst. In - ~ ~
20 addition epoxy resins containing low levels of chlorine are required to prevent deactivation of .; -
this catalyst.
European Patent Application 300,504A discloses the preparation of flexi bili~ed -. ~ ".
~ . .
epoxide compounds by reacting an aromatic diol with diepoxides which are diglycidyl ethers of `
25 aromatichydroxy compounds, or a bis-(labile hydrogen functionalized) alkoxy arylene . ~ .
compound. European PatentApplication 315,164disciosesa coating resin composition which
comprises the reaction produn of a diepoxide compound which is a diglycidyiether of a
bisphenol A (bis-(4-hydroxy phenyl)propanel initiated polyalkylene oxlde, a bisphenol,
optionally a bisphenol diglycidylether, and an amine, having an actlve hydrogen. It is disclosed
30 therein that the bisphenol A initiated ~olyalkylene oxide diepoxide ~esults In an improved
electrodeposition coating. Commoniy assigned ~atent application EP 253,405 discloses an ~:~
ad~Janced epoxy cationic resln prepared by reacting In the presence of a sultable catalyst (A) a
composition comprlsing (1) at ieast one diglycldyl etner of a polyoi and (2) at least one
diglycidyl ether of a dihydric Dnenol wlth (B~ at least one dinydric nnenol and or tlonally (C) a
35 monoflJnc;ional capping agent. Componen~s ~A) ana (B) are e~nDloyea In such quantities tna~
the resultant epoxy resin has an average epoxide welght from 350 to 10 OOQ
- 2~
:" .:,
"`'.
- -
i;
WO 93/041 04 ~ I ~i 7 t~ PCI /US92/07234
T-le resins disclosed exhibit some flexibility problems and do not provide superior
anticorrosion prope!ties. Additionally, some of the processes disclosed for preparing the resins
do not efficiently incorporate the polyalkylene glycol containing diepoxides into the backbone : ~
of the advanced resins. .:
: .
In electrodeposition it is desirable that the resins in the coating have a low
viscosity to facilitate processing and control of the coati ng thickness. It is also desi rable that
such coatings demonstrate low water permeability as this property is important in the
inhibition of corrosion. Additionally it is desirable that such coatings demonstrate good
10 flexibility. The problem isthat asthe resin viscosity is lowered and the coating flexibility is
increased, the water permeability of the coating is usually also increased. What is needed are
resins for use in coatings, including elec~rodeposition coatings, which exhibit lower viscosities,
result in coatings with higher flexibility and lower water permeability. What is further needed,
is an advanced resin which has efficiently incorporated therein the flexibilizing agents. What is
15 further needed is a process which allows efficient incorporation of the flexi bi i izi ng agent i nto
the backbone of the advanced epoxy resin. -:
The invention relates to flexibilized advanced epoxy resins comprising the residue :
of :-
A. one or more polyglycidyl ethers of a water or di- or triinydroxy substituted Cl .6
hydrocarbon initiated polybutylene glycol;
B. one or more polyaromatichydroxy co~pounds; and
C. one or more polyglycidyl ethers of polyaromatichydroxy compounds;
25 wherein substantially all of the glycidyl ether moieties of the polyglycidyl ethers of
polybutylene glycol are bound to the polyaromatichydroxy compounds through the reaction
product of the glycidyl ether moieties with the arornatichydroxy moieties;
each polyaromatichydroxy compound is bound to at least one polyglycidyl ether ofpolybutylene glycol or to at least one polyglycidyl ether of a polyaromatichydroxy compound
30 through the reaction product of an aromatichydroxy moiety with a glycidyl ether moiety; most
of the polyglycidyl ethers of polyaromatichydroxy com~ounds are bound to at least one
polyaromatichydroxy compouna through the reaction i~roauct of glycidyl ether moiety ana an
aromatlchydroxy molety; each reslaue of a polygiycidyl ether of polyaromatlcny~roxy
cornpound Is bound to at ieast one oolyaromatichydroxy comoound through the reactlon of 2
35 glycldyl ether moiety and an aromatichydroxy molety;
where!n the mole rallo of polyaromatichydroxy compound to oolyglycidyl ether of
polybutyîene qlycol is at least 2.0 to 1.0: and sufficient i~oiygiyc dy! ether of
-3- :
WO 93/04104 ~ 1 1 4 7 ~ ~ PCr/US92/07234
polyaromatichydroxy compound is present in the resin such tha-t the terminal moieties of the
resin are glycidyl ether moietles from the polyglycidyl ethers of polyaromatichydroxy
compounbs.
In another aspect the invention is a process for the preparation of such
flexibilized advanced epoxy resins cornprising
A. reacting a polyglycidyl ether of a di- or tri- hydroxy C1 6 hydrocarbon or water
initiated polybutylene glycol with two or more moles of a polyaromatichydroxy compound per
mole of polyglycidyl ether of polybutylene glycol under conditions such that substantially all of
10 the glycidyl ether rnoieties of the polyglycidyl ether of polybutylene glycol react with .
aromatichydroxy moieties of the polyaromatichydroxy compounds;
B. thereafter reacting the reaction prc duct from A with an excess of one or more
polyglycidyl ethers of polyaromatichydroxy compounds, optionally one or more
polyaromatichydroxy compounds, and optionalIy one or more chain terminators, under :
15 conditions such that the arornatichydroxy moieties rea with the glycidyl ether moieties .
wherein the terminal functional moieties of the product are glycidyl ether moieties.
In anotheraspectthe invention relatesto flexibilized advanced epoxy resins ; .
prepared by the above-desaibed proce~s. In yet another aspect the i nvention is directed to . .
20 advanced epoxy cationic resins having a charge density Qf from 0.2 to 0.6 milliequivalents of ` .
cationic charge per gram of resin, wherein the terminal epoxy moieties of the above-described . ~ :~
res~ns have been reacted with a nucleophile and treated to render the resulting moieti~s ' ::
cationic. ~ . .
The advanced epoxy resins of the invention demonstrate improved flexibility and
improved corrosion protection of substrates coated with such compositions as compared to
conventional resins. The flexibilized advanced epoxy resin compositions of the invention and
the process for preparation of the resin also demonstrate a more efficient incorporation of the
flexibilizing agent into the backbone of the resin. The flexibilized advanced epoxy resins of the
30 invention demonstrate improved e!ongation and imDact resistance along with exceptionai
combination of elongation, impa~t resistance, and corros~on resistance as compared to
conventional resins.
A major advantage of the invention 15 the efficient incorporation of an Improved3 flexibilizlng 3gent ,nto tne internal backbone Ot t~.e advancecl eDoxy resins. Thus the backbone
of the flexibllized eooxy resln of this ~nventlon contalns at least one unit of the flexibilizing
comoonent in its Inlerior. The flexibilizing unlt is the residue of a polyglycidyl ether of a water ~ . .
or di- or ~n hyc~roxy s~Jbstltuted C1-6 nyarocarbon Inltlated polyDutylene glycol, whicn means ' ` ~-;
..
211~'7-g5
WO ~3/04104 PCI/US92/07234
herein that the glycidyl ether moieties of such compound have been reacted wlth
aromatichydroxyl groups so as to incorporate such polybutylene glycol into the backbone of
the flexibilized advanced epoxy resins. The flexibilizing agent is ~repared by reacting water or `;
a di- or tri- hydroxy substituted C1-6 hydrocarbon with butyiene oxide units, so as to react the
5 hydroxy units or water with the butylene oxide, thereby forming a polybutylene glycol with a
central unit comprising oxygen or the residue of the di- or tri- hydroxy substituted C1-6
hydrocarbon. Thereafter the terminal hydroxy moieties of the polybutylene glycol are reacted
with an epihalohydrin to form terminal glycidyl ether moieties. Such reactions are well-known
to those skilled in the art. Polybutylene glycol as used herein refers to compounds which
10 contain more than one butylene oxide unit within the backbone, and includes compounds
wherein one butylene oxide unit is added to each active hydrogen unit of the ini~iator. `~
Included among the initiators for the flexibilizing unit are water, ethylene glycol,
propylene glycol, butane diols, such as 1,4 butane diol, trimethyol propane, neopentylglycol
t S and glycerol. The most preferred initiator is water. Preferably, the polyglycidyl ether of
polybutylene glycol has a molecular weight of 140 or greater, most preferably 200 or greater
and most preferably 300 or greater. Preferably the polyglycidyl ether of polybutylene glcyol,
has a molecular weight of 2000 or less, more preferably 1000 or less, and most preferably 600 or .
less. rhe molecular weights referred to here are number average molecular weights. The
20 flexibilized advanced epoxy resins of this i nvention preferably contain S percent or greater by
weight of the residue of the glycidyl ethers of polybutylene glycol in the backbone, and more
preferabiy 10 percent or greater. Preferably, the flexibilized advanced epoxy resins of this
invention contain 50 percent or less by weight of the residue of polyglycidyl ethers of ~ ~ ~
polybutylene glycol in the backbone, more preferably 30 percent or less by weignt. In a ;
25 preferred embodiment, the glycidyl ethers of polybutylene glycol correspond to formula 1
R R
Z~HCHO~CH2-T-C~CH~) 1
30 wherein R is independently in each occurrence hyarogen, methyl or ethyl with the proviso that
for each
R R
~HCHO~
J
~5 ~:
unlt either ~oth of R are methyl or one R is ethyl and the other is hydrogen;
T Is inde~oendently in each occurrence a direct ~ond or the molety
' ~
, :, '~;
` ~' '
WO 93fO4104 2 1 1 4 7 ~ ~ PCI/US92/07234 ~
Rl , .~
,,~
-OCH2-- ;
!:H2CI : ,
S '.
R' is independently in each occurrence hydrogen or a Cl~ alkyl moiety;
Z is independently in each occurrence oxygen or .,
\ Jb ; ~``
X is independently in each occurrence a straight or branched chain C1-6 alkyl rnoiety; .
a Is independently in each occurrence a positive real number of 1 or greater;
b is independently in each occurrence 2 or 3.
15 Z Is ,t)referably oxygen. X is ~referably a straight or branched chai n Cl .4 alkyl moiety. Preferabiy, . .
a is a real number of from l to 16; more preferably from l to 8 and most preferably of from 2
to 5. Preferably b is 2.
The ini~iator used in this invention preferably is water or corresponds to Formula
20 2~
X~ ) 2 ~`
b
25 wherein X and b are as described hereinbefore.
The polyglycidyl ethers of polybutylene glycol are reacted with
polyaromatichydroxy compounds. Polyaromatichydroxy compounds referred herein to
compounds which on average contain more than one hydroxy group and which comprises a
30 hydrocarcon backbone containing aromatic moieties, wherein the hydroxy moieties are bound ~ -~
to aromatic moieties di rectly. Preferably the Dolyaromatichydroxy hydrocarbons have two or
more aromatic bound nydroxy grouos. The polyaromat,chydroxy comDounds can oe further
su~stltuted on the hydrocar~on backbone by halogen moletles. Among preferreci classes of
oolyarornatichydroxy comDounds are the bis~nenols, halogenated bisr henols, hydrogenated
35 oisphenols, and novolac reslns, .e. the reactlon ~oroauct of ohenols anci simDle aldehydes,
preferabiy formaldehyde ana hydroxy benzaidehyde. Preferred polyaromatichyaroxy
compounds ~seful ,n this Invention correspond to formula 3: ,
`6- ~ `
'"`-.;'``'
~ `
WO ~3/04104 2 ~ 1 4 ~t~ ~` PCI`/USg2~07234
A~OH)C 3
5 wherei n
Ar is an aryl moiety; aryi moiety substituted with an alkyl or halo moiety; a polyaryl moiety
wherein the aryl moieties are connected by direct bonds, alkylene, haloalkylene, cycloalkylene,
carbonyl, sulfonyl, sulfinyl, oxygen, or sulfur moieties, such polyaryl moieties being optionally
substituted with an alkyl or halo moiety; or the oligomeric reaction product of an aldehyde and
10 phenol;
and c is a positive real number greater than 1.
More preferred polyaromatichydroxy compounds include those corresponding to
forrnulas4and 5: . `
(R2)m (R2)m
HO~R3 ~OH 4
HO~ R4 ~ R4 ~OH S
(R~)m'
P
wherein;
R2 is separately m each occurrence C1-3 alkyl or a halogen;
~3 is seoarately in each occurrence C- o alkylene, Ct-10 haioalkylene, C~. o cycloalkylene,
35 carbonyl, sulfonyl, sulfinyl, oxygen, sulfur, a dlrect ~ona or a molety corresponding tO tne
formula
-7-
WO 93/04104 ~ PCr/VS92/07234
(R2)",~H
R4 is inclependently in each occurrence Cl-1o alkylene or Cs so cycloalkylene;
Q is independently in each occurrence a C1-lO hydrocarbyl moiety;
Q' is independently in each occurrence hydrogen, cyano, or a Cl la alkyl group;
m is independently in each occurrence an integer of O to 4;
m' is independently in each occurrence an integer of from O to 3; ; -~
p is a posi~ive real number of O tO 1 0.
R3 is preferably C1-3 alkylene, C1-3 haloalkylene, carbonyi, sulfur, or a direct bond.
R3 is more preferabiy a direct bond, Cl 3 alkylene, or fluorinated propylene ( = C(CF3)2-). R3 is -
most preferably propylene. R2 is preferably rrtethyl, bromo or chloro; and most preferably
methyl or bromo. R~ is preferably C1.3 alkylene or polycyclic moiety corresponding to the ~ ;
foimula
.-~
'25 ~ ~:
30 wherein t is an average number from l to 6 inclusive, preferably l tc3 3, most preferably l . ~ -~
Preferably, m and m' are independently an integer of O to 2. Preferably, p is a oosltive real
nurn~er of O to 8; and more preferably ~ to 4. p reoresents an average number, as the
cornoounds to which it refers are generally found as a mixture of compouncts with a
aistrli~utlon of the units to which p refers. Cycloalkyiene as used herein refers to monocyctic
35 and poiycyclic hydrocarbon moieties. ; `
The most preferred class of polyaromatichdroxy compounds are the dihyaroxy
phenois. Preferable dihydroxy phenols include those wh~cn contaln substltuents that are non- ~ ~
-8- ~ :
~''~`.
WO 93/04104 - ~ 1 1 47 ~ ~ PCI/US92/07234
reactive with the phenolic groups. Illustrative of such ohenols are 2,2-bis(3,5-dibrorno-4-
hydroxyphenyt) propane; 2 ,2-bis(3,5-di bromo- 2 ,4'-hyd roxyphenyl) propane; 2 ,2-bl s(4-
hydroxyphenyl) propane; 2,2-bis~2,4'-hydroxyphenyl) propane; 2,2-bis(3,5-dichloro-4-
hydroxyphenyl) propane; 2,2-bis(3,5-dichloro-2,4'-hydroxyphenyl) propane; bis (4-
hydroxyphenyl) methane; bis (2,4'-hydroxyphenyl) methane; 1,1-bis(4-hydroxyphenyl)-1-
phenyl ethane; 1,1 -bis(2,4'-hydroxyphenyl)-1 -phenyl ethane; 1,1-bis(2,6-dibromo-3,5-
dimethyl-4 hydroxy phenyl) propane; bis (4-hydroxyphenyl) sulfone; bis (2,4'-hydroxyphenyl)
sulfone; bis (4-hydroxyphenyl) sulfide; bis (2,4'-hydroxyphenyl) sul fide; resorci nol;
hydroquinone; and the like. The preferred dihydroxy phenolic compounds are 2,2-bis(4-
10 hydroxyphenyl) propane, 2,2-bis(2,4'-hydroxyphenyl) propane (a mixture of the two is
commonly referred to as bisphenol A).
As used herein haloalkyl refers to a compound with a carbon cham and one or
more of the hydrogens replaced with a halogen, and includes compounds where all of the
15 hydrogen atoms have been replaced by halo~en atoms. Alkylene as used herein refers to a
divalent alkyl moiety. ` `
The term hydrocarbyl means any aliphatic, cycloaliphatic, arornatic, aryl
substituted aliphatic or cycloaliphatic, or aliphatic or cycloaliphatic substituted aromatic
20 groups. The aliphatic groups can be saturated or unsaturated. Likewise, the term
hydrocarbyloxy means a hydrocarbyl group having an oxygen linkage between it and the
carbon atom to which it is attached. Polyaryl moiety as described herein refers to compounds
which contain more than one aromatic ring which may be fused, bonded by direct bond, or
connected by alkylene, haloalkylene, cycloalkylene, carbcxyl, sufonyl, sulfinyl, oxygen or sulfur
25 moieties. `
.
The term residue as used herein refers to the portion of a starting mateffal
remaining in the final product after completion of the reaction. The term residue of a
polyaromatichydroxy compound means herein that a polyaromatichydroxy comDound has
30 been incorporated into the backbone of the flexibilized advanced epoxy resin wherein the
aromatlcnydroxy moleties have reacted with glycidyl ether moleties of the glycidyl ether of
polybutylene glycol, or the glycidyl ether moieties of a glycidyl ether of an aromatlcnyàroxy
comDound. In a preferred embodiment, the polyaromatichydroxy compounds are nommally
dihyaroxy aromatlc comDounds meaning that tne dihydroxy comDouncis are a mlx~ure of
35 compounds resuitlng from the prepara~ion ~rocess, and on average Ihe compounas present
have near two nydroxy moietles per molecule.
"",, .
9 ~
", '` ".
WO93/04104 21 1~7~ PCI/US92/07234 ~ ~
The residue of polyglycidyl ethers of poiyaromatic hydrocarbon means,here~r~ ~ -
that at least one of the glycidyl ether moleties has reacted with an aromatichydroxy moiety, ~ ;.
wherein the polyaromatichydroxy compound may be further reacted with a polyglycidyl ether ~;
of a polybutylene glycol. The resins of this invention preferably have terminal giycidyl ether
S moieties which are derived from the glycidyl ethers of polyaroma~ichydroxy compounds. A
small portion of the flexibilized advanced epoxy resins of this invention contain polyglyciyl
ethers of polyaromatic hydrocarbons that have not reacted with an aromatichydroxy moiety. -
General Iy these materials are not removed prior to utilization.
....
Polyglycidyl ether of a polyaromatichydroxy compound rneans a hydrocarbon . .~
compound containing one or more aromatic moieties, wherein more than one epoxy (1,2 ~ ~:
glycidyl ether) moiety is bound to the aromatic moieties. In another embodiment it refers to a
mixture of compounds which contains, on average, more than one epoxy moiety per molecule : :
bound to aromatic moieties. Polyglycidyl ether of a polyaromaticnydroxy cornpound as used
1 S herein includes partially advanced epoxy resins i.e. the reaction OT a polyglycidyl ether of a . .
polyaromatichydroxycompound and one or more polyaromatichyaroxy com~ounds, whereln : . `.
the reaction product has an average of more than one unreacted e~oxide unit per rniolecule.
, ~
Polyglycidyl ethers of a polyaromatichydroxy compounds (polyepoxides) are - :-
20 prepared by reacting an epihalohydrin with a polyarornatichydroxy compound. The
preparation of such compounds is well known in the art. See Kirk-Othmer Encyclopaedia of . :
Chemical Techno!ogy 3rd Ed. Vol.9 pp 267-289, "The Handbook of Epoxy Resins" by H. Lee and ~;:
K. Neville (1967) McGraw Hill, New York, and US Patents 2,633,458; 3,477,990, 3,821,243; .~;
3,907,719,3,975,397; and 4,071,477.
:~`
The epihalohydrins correspond to formula 6:
R ~
CH2 ~H2Y 6
O . '; ~
wherel n
35 Y is a halogen, preferabiy chloro or bromo, and most oreferably cnloro; ;;
and R; is as previously defined.
- -
.,~:
- t 0~
:
, .,:
WO 93/04104 ~ 7 ~ ~ PCl`/US92~07234
The polyglycidyl ethers of polyaromatichydroxy compounds useful in the
invention preferably correspond to formula 7 ;
R
A~(O-CH2(~H~)C 7
wherein Ar, R and c are previously defined. Rl is preferably hydrogen or methyl. Preferably, c is :
10 5 or less, more preferably from 1 to 3.
The polylycidyl ethers of polyaromatichydroxy compounds more preferably
correspond to one of formulas 8 or 9: ~
R' (R2)m (R2)m R1 (R2)rrl (R2)m R ~-
CH2CcH20~ R ~CH2CllCH2~ R3~CHzC\tH2
8 ~`~
R~ :
CH2CCH20
CH2CCH2~RO4/~ R4 ~~H2~ icH 2 ~ ~
(R2~m (R2)~
'~'s`
. 1 ~ i . .
, ~
WO 93/04104 2 1 1 ~ 7 ~ ~ PCI`/USg2/07234
wherein ~1, R2, R3, R4, m, and m~ are as defined previously; r is a positive real number of 0 to 40;
and
s is a positive real number o~ 0 to 10. Preferably, r is a positive real nùmber of 0 to 10, and most
preferably 1 to 5. Preferably, s is a positive real number of 0 to 8; and most preferably 1 to 4. All
5 of the variables referred to herein as positive real numbers, i.e. r and s, are average numbers as
the compounds referred to contain a distribution of units. :
- . .
Preferable polyglycidyl ethers of polyaromatichydroxy compounds are the
glycidyl ethers of dihydroxy phenols, bisphenols, halogenated bisphenols, alkylated bisphenols, I
10 trisphenols, phenol-aldehyde novolac resins, halogenated phenol-aldehyde novolac resins,
alkylated phenol-aldehyde novolac resins, hydrocarbon-phenol resins, hydrocarbon- ~ ~
halogenated phenol resins, or hydrocarbon-alkylated phenol resins, or any combination :
thereof and the like. Even more preferable polyglycidyl ethers of polyaromatichydroxy
compounds include, for example, the diglycidyl ethers of resorcinol, catechol, hydroqulnone,
isphenol, bisphenol A, bis,ohenol AP ( 1,1-bis(4-hydroxylphenyl)-1-phenyl ethane), bisphenol F, ~ :
bisphenol K, tetrabromobisphenoi A, phenol-formaldehyde novolac resins, alkyl substituted ~ ~ -
phenol-formaldehyde resins, phenol-hydroxybenzaldehyde resins, cresol- ~;
hydroxybenzaldehyde resins, dicyclopentadiene-phenol resins, dicyclopentadiene-substituted
phenol resins tetramethylbiphenol, tetramethyl-tetrabrornobiphenol, A
20 tetramethyltribromobiphenol,tetrachlorobisphenolA, tetrabromobisphenolA,any
combination thereof and the like. Preferably the polyglycidyl ether of the poiyaromatichydroxy
cornpounds is a riominally diglycidyl ether of a polyaromatichydroxy compound, meaning t'nat
the aetual materials used are a mixture of compounds resulting from the process for
preparation wherein the average number of glycidylether rnoieties per molecule approaches
25 two.
Optionally the advanced flexibilized epoxy resins of this invention can contain the
residue of a chain terminator. In practice a chain terminator is a rnaterial which has only one
reactive moiety containing an active hydrogen atom. Such chain terminator functions to
30 reduce the molecular weight of the proposed material and are well known i n the art. An
example of a preferable chain terminator is paratertiarybutyl phenol.
In the preferred embodiment ~herein the polyaromatichydroxy compound is a
nommally diaromatichydroxy compo~Jnd, and tne r olyglycidyl ether o; a polyaromatichy~roxy
35 compound is nomlnally a aiglycidyl ether of a a aromatlchydroxy compound, the advancecl
flexlbilized resins of this ~nvention correspond to formula 10:
:
'~
W~9~/04104 ~ 7~, PCI/llS9'2/07234
(~H2TCHCH~-OArO-CH21HTCH2-OAro-E)
B ~ H2T~HCH2-OAr ~ CH2CHTCH2-B-CH2TFHCH2-OAr ~ CH2fHTCH2-OArO-E~
\ OH OH OH OH
10 wherein
B is independently in each occurrence
Z~LH~HC~;
E is independently in each occurrence a moiety according to one of the formulas
~H2TCHCH2 or
O
-Ar-CH2 1 HTcH-8t;cH2TfHcH2 OArO-CH2 FHTCH2-OArO-~)
OH OH OH
d is independentiy in each occurrence a number of from 0 to 2; ~:
25 e is independently in each occurrence 0 or 1; and Ar, R, T, Z, X, a, b and c are as defined
hereinbefore
In one preferred embodiment of the invention, the flexibilized advanced epoxy
resin are converted to flexibilized advanced epoxy ~ationi~ resins which have a charge density
30 of from 0.2 to 0.6 milliequivalents of cationic charge per gram of resin. Such resins are ~repared
by reacting the terminal glycidyl ether moietieswith a nucleophile and thereafter convert~ng
the reaction product to ca~ionlc s~ecies. Nucleophiles useful for ,~erformlng ~his reactlon are
~ell-known to t~lose skilled in the art. Dreferred nucleoQhiles are rnonobaslc neteroaromatic
nitrogen comDounds, tetra(lower alkyl) thioureas, sulficdes corres~ondincl to formula 11:
3' R6-S R6 - 11
amlnes corresponding to formula 12~
-13-
: ,:
WO 93/04104 2 1 1 ~ 7 ~ P~ US92/07234
R7-~ R8 12 ~ ~ `
R8 ' ~. .
or phosphi nes correspondi ng to form ul a 13 :
R9-~-R9 13
R9 ";
wherein;
R6 is i ndependently i n each occurrence lower alkyl, hydroxy lower alkyl or two of R6 may
10 combine as one 3 to 5 carbon atom alkylene radical thereby forming a heterocycloalkylene `
moiety;
R7 is indeper.dently in each occurrence hydrogen, hydroxyalkyl, lower alkyl, aralkyl or aryl;
R8 is inaependently i n each occurrence hydrogen, lower alkyl, hydroxy lower alkyl, the moiety
.
R 1 1 - ~
< R l l ; ` :
or two of R8 m,ay cornbine to form an alkylene radical having from 3 to 5 carbon atoms;
R9 independently in each occurrence lower alkyl, hydroxy lower alkyl or aryl;
20 R10 is independently in each occurrence a C2-lO alkylene ~roup;
R1 1 ,s independently in each occurrence lower alkyl.
Preferably the nucleophile is an amine, more preferably a primary or secondary ~ ~
amine. ; ~ `
Representative nucleophilic compounds are pyridine, nicotinamide, quinoline,
iso,riuinoline, tetramethyl thiourea, tetraethyl thiourea, hydroxyethylmethyl sulfide,
hydroxyethylethyl sulfide, dimethyl sulfide, diethyl sulfide, di-n-propyl sulfide, methyl-n-,oropyl
sulfide, methylbutyl sulfide, dibutyl sulfide, dihydroxyethyl sulfide, bis-hydraxybutyl sulfide,
30 trirnethylene sulfide, thiacyclohexane, tetrahydrothiophene, dimethyl amine, diethyl amine,
dibutyl amine, 2-(methylamino)ethanol, diethanolamine, N-methylolperidine, N-
ethylpyrroliaone, N-hydroxyethylpyrrolidine, trimethylphosphine, trlethyl-ohosphine, trl-n-
butyl-Dhosphine, trimethylamlne, triethylamme, tn-n-Dropylamine, tn-lsobutyldmine,
hydroxyethyl-dimethylamine, ~utyldimethyiamine, trihyaroxyethylamlne,
35 trl~nenylphospnorus, and N,N.I\-dimetnyipnenethylamlne: anr the ketlmlne derlvatives o~
polyamlnes containlng secondary and c~nmary am~lno groups such as those ~roduced by the
reactlon of diethylene triamine or N-arr inoetnylpipera~me with acetone, methyi ethyl ketone
or methylisoDutyl ketone. ~ -~
-la
WO 93~04104 ~ PCI /US92/07234
In a preferred embodiment the nucleophile is a pnmary or secondary amlne, the
polyaromatichydroxy compound is a diaromatichydroxy compound, and the polyglycidyl ether
of a polyaromatichydroxy compound is a diglycidyl ether of a diaromatichydroxy compound,
5 and sùch compounds preferably correspond to the following formula 14
~H,TCHC112~0ArO-C112~;1TCH-OArO-Ci)
B tCH2TfHCH2-OArO~CH2FHTCH2-B-CH2T I HCH2-OAr~ CH2CHTCH2-OArO~
~ OH OH OH Oh
wherein~
G is independently in each occurrence a moiety according to one of the formulas:
~H2TCHCH2 N -(R7)(RB)2 --CH2TCHCH2-O-H -
OH A- ; (R7)(R8)2 N~A or ~ ~:
-... ...
OArO-CH2 l HTCH-BtCH~TfHCH2 0ArO-CH2 j~HTCH2-OArO~
OH OH Ql I
A- is the anion of an acid as described here;nafter; . :
and Ar, B, R, R7, R8, T, Z, X, a, b, c, d and e are as des~ribed hereinbetore.
The flexibilized advanced epoxy resins of this invention preferably exhibit a
weight average molecular weight of 900 or greater, more preferably 1200 or greatef, and most
preferably 1500 or greater. The flexibilized advanced epoxy resins of this invention preferably
have a molecular weight of 50,000 or less, more ~referably 30,000 or less, and most preferably
20,000 or less. The flexibili~ed advanced epoxy resins of this inventlon preferabiy have an eDoxy : ~:
equivalent weight (EEW~ of 450 or greater, more preferably 600 or greater, and most ~ .
preferably 800 or greater. The flexlbilized advanced epoxy reslns of this inventlon preferabiy
ave an EEW of 5,000 or less, more preferably 4,000 or !ess, and most prerera~ly 3,000 or less.
The Inventors na\/e recognized tnal tne reacti~Jity of a ~olyglycldyl ether of a .
polybutylene glycol with a polyaromatlchydroxy com~ound Is much iower Ihan the reactlvlty of
a polyglycidyl ether or a polyarornatichyaroxy comr~ound wlth a oolyaromatlchyclroxy
compound. Theretore, unless the process conaitlons are carefully chosen, It Is difficult to
'~''
WO93/04104 21 ~ PCr/US92/07234 .
efficiently Incorporate the poiyglycidyl of a polybutylene glycol in~o the internal structure of
and advanced epoxy resin. ~he process of this invention involves first reacting the giycidyl ether ~-
of a water or di- or tri hydroxy substltuted C1.6 hydrocarbon initiated polybutylene glycol with
the polyaromatichydroxy compound under conditions such that substantially all of the glycidyl ;
5 ether moieties on the polyglycidyl ether of the polybutylene glycol are reacted with
aromatichydroxy groups. In the second step the reaction product is reacted with a polyglycldyl
ether of a polyaromatichydroxy compound under conditions such that the terminal ' -~
aromatichydroxy moieties of the reaction ~roduct react with the glycidyl ether moieties of the
polyglycidyl ether of the polyaromatichydroxy compound, such that the terminal groups of the ;
10 flexibilized epoxy resin are primarily glycidyl ether moieties. OptionalIy, additional
polyaromatichydroxy compounds may be present in the second step to facilitate the further
advancement of the flexibilized epoxy resin. If desired a known chain terminator may be ; ~-
present in the reaction mixture in small quantities. ~ `
. .
In the first step, the polyglycidyl ether of the polybutylene glycol is contacted ~;
with the polyaromatichydroxy compound neat, in the absence of solvent, or in the presence of
an organic solvent which demonstrates low affinity for water. Such solvents include aromatic ~ `
hydrocarbons, mixtures of aromatic hydrocari30ns and alkanols, glycol ethers and ketones. It is
advantageousto include epoxy resin advancement catalyst, such as compounds containing
20 amine, phosphine, heterocyclic nitrogen, ammonium, phosphonium, arsonium, or sulfonium
mo~eties. Preferred catalysts are the ,ohosphonium compounds. In the embodiment where the
catalyst is a phosphonium or an amine preferably 500 ppm (parts per million~ or more of the
catalyst ~s present, more preferably 700 ppm or more. Preferably such catalyst is present in
amounts of 3,000 Dpm or less, more preferably 2000 ppm or less. Thereafter the reaction
mixture is heated until an exotherm begins, generally at from 140 to 1 50C. Preferably, the `~
temperature of the mixture is increased at a rate of from 1 to 2C per minute until the
exotherm begins. The temperature is maintained at levels at which the reaction continues, until
the reaction is completed. In those embodiments wherein a phosphonium catalyst is used a
reaction generally stops itself. Where other catalysts are used, the reaction may be quenched
30 by cooling. The reaction time is dependent upon the concentration of catalyst, materials
present, presence of solvent and the reactivity of materiais. Preferably reaction times are 15
mlnutes or greater, more preferably 3û minutes or greater. Preferably reaction times are 4
hours or iess, and more preferably 3 hours or less In a Dreferred embodiment, the amount of
oolyaromatichydroxy compound contacted with the ootyglycidyl ether of the polybutylene
35 glycol Is s~,fficient to react wltt~ all of the glycidyl ether molet~es of the potyglycidyl ether of
Dolybutylene glycol. Preferabiy two moles of ~olyaromatlchyaroxy material or greater is
oresent per mole of polyglycidyl etner of polybutylene glycol. In some embodiments It may be
aavantageous to nave a slgnificant excess of poiyaromallchydroxy material where s;-ch
- 16-
WO 93/04104 2 1 ~ ~ 7 ~ PCI/US92/07234
material would be advantageous in further advancmg the reaction product in the second ste~.
Once the reaction is complete, the reaction product may be recovered from the reaction
mixture, or alternatively and preferably the ~olyglycidyl ether of the polyaromatichydroxy
compound is thereafter added to the reaction mi xture and the second step of the reacti on i s
5 performed.
In the preferred embodiment where a diaromatichydroxy compound is reacterJ ~
with the polyglycidyl ether of the polybutylene glycol based material the reaction product of
thefirststeppreferablycorrespcndstoFormula 15~
Z~H~Ho3~cH2-T-~H~-oAroH ) 15
wherein Z, T, R, R1, Ar, a, and b are as hereinbefore defined.
1 5
In the second step of the reaction, the reaction product of the first step is ~ . ;
contacted with a polyglicyidyl ether of a polyaromatichydroxy compound, and additional
polyaromatichydroxy compound andlor chain termi nator. Preferably, the molar amount of .
polyglycidylether of a polyaromatichydroxy compound is present in a ratio of greater tt1an 1.0 ~ `
20 as compared to the moles of the above-mentioned reaction prodiuct of the first stej2 and more
pre~rably 1.5 moles or greater. Thereafter, the mixture is heated until exotherm occurs. `
Optionally, catalyst for the advancement of eooKy resins may be present. Alternatively, a : `.~
sufficient amount of catalyst may be introduced in step 1, such that no further catalyst need to
be added in the second step. The reactants in the second step may be reacted neat or in the
25 presence of a solvent. Solventswhich may be used are those which are typically used as solvents ~ -
for epoxy advancement reactions. A reaction in solvent may be advantageous wherein heat : 5
control is desired. The advancement reaction is preferably performed at a temperature of 1 30C
orabove,asbelow 130Cthereactiontimeistooslow. Preferablythereactionisperformedata
temperature o~ 230C or less, the poiymer reacts to fast above such temperature and unwanted
30 colors rnay be formed due to the Dresence of oxidated byproducts. More preferably the
reaction tem~erature is 1 80C or below. The temperature wnich may be used for the reaction .
depends on whether or not a solvent Is used, and its nature. The reaction mixture is preferably
neated at a rate such that the temperature increases trom 1 to 2C per minute until exotherrn is
achieved. Thereafter eievated ~emDeratures are maintained until the desired molecular weight
35 and epoxy eauivalent v~elghts are reached. The Dolyeooxlde acivancement reaction Is ailowed ;
to ~roceed for a ~Ime sufficient to result in substantlaily comDiete reaction, preferably 15
minutes or greater, !nore Dreferai~ly 30 mlnutes or greater. Preferabiy the maximum reaction
time is 1~ hours or less and more ~referabiy 2 hours omess. The flexibili~ed advanced epoxy
-~ 7-
. :
WO 93/04lO4 ~ 1 1 4 7 (~ ~ PCl`/US92/07234 : i-
resinsof this invention can thereafter be recovered and formulated for use in vario~s coatings ;;
applications~ The flexibili~ed advanced epoxy resins of the invention may be recovered in a
semi-solid or solid state by means well known in the art.
The coating compositions which can incorporate the flexibilized epoxy resins of
this invention include powder coating compositions, food and beverage can coating
compositions and ambient cure coati ngs useful in industriat maintenance applications. In those
embodiments where the resin will be used in marine or industrial maintenance applications,
powder, or food and beverage can coatings, the resin may be recovered and then converted to
10 a form useful for such coatings.
~:-
In one preferred embodiment, the flexibilized advanced epoxy resins of this ~'
invention are converted to cationic resi ns ;.or use i n cathodic electrodeposition coatings by
reacting at least some of the glycidylether moieties of the resin with a nucteophilic compound
15 and adding an organic acid and water at some point during the pre~oaration. It is also ~oossible
to react at least some of the glycidyl ether moieties with a nucleophile salt formed by ; -
prereacting the nucleophile with the organic acid. .~
~ . .. ..
Substantially any organic acid, especially a carboxylic acid, can be used in the20 conversion reaction toform onium salts so long as the acid is sufficiently strong to p-omote the
reaction between the nucleophilic compound and the glycidyl ether moieties of the resin. In
the case of the salts formed by addition of acid to a secondary amine/epoxy resin reaction
produc, the acid should be sufficiently strong to protonate the resultant tertiary amine
pro~uct to the extent desired. Monobasic acids are normally preferred ~H ~ A-). Preferable
25 organic acids include, for example, alkanoic acids having from 1 to 4 carbon atoms (e.g., acetic
acid, propionic acid, etc.), alkenoic acids ha~in~ up to 5 carbon atoms (e.g., acrylic acid,
methacrylic acid, etc) hydroxy-functional carboxylic acids (e.g., glycolic acid, lactic acid, etc.)
and organic sulfonic acids (e.g., methanesulfonic acid), and the like. Presently preferred acids
are lower alkanoic acids of 1 to 4 carbon atoms with lactic acid and acetic acid being most
30 ,oreferred. The anion can be exchanged, Qr course, by conventional anion exchange techniques.
See, for example, US Patent 3,959,106 at column 19. Preferable anions are chloride, bromide,
bJsulfate, bicaroonate. nitrate, dinyclrogen ohosQhate, lactate and alkanoates of 1-4 carbon
atoms. Aceta~e and lac~ate are the most preferred anions.
The con~ers~on reaction to form cationic resms Is normally conducted by blenaingtherea.antstogether. ~:iooaresultscanbeacnievedbyuslngsubstantlallystoichiometnc
amounts of reactants although a slight excess or deficiency of the epoxy- containi ng resi n or
.he nucleoDhil~ic compounds can Qe usec. ~ tn weak ac!ds, useful ratlos of tne reactants range
1 8~
WO13/114104 211~7~ PCI/US9Z/07Z34 :~
from 0.5 tO 1.0 equivalent of nucleoohilic compounds per glycidyl ether moiety of the resin and
for organlc acids from 0.5 to 1.1 equlvalents of organic acid per glycidyl ether moiety. These
ratios, when combi ned with the preferred epoxide content resins described above, provide the ; ~`
desired range of cationic charge density required to produce a stable dispersion of the coatlng
composition in water. With still weaker acids a slight excess of acid is preferred to maximi2e the :
yield of onium saits. When the nucleophilic compound is a secondary amine, the amine-epoxy ~
reaction can be conducted first, followed by addition of the organic acid to form the salt and ..
thus produce the cationic form of the resin. ~
,
For the onium-forming reactions, the amount of water present can be varied so
long as there is sufficient acid and water present to stabilize the cationic salt formed during the
course of the reaction, preferably water is present in amo~Jnts of from 5 to 30 moles per epoxy ... ..
equivaient. It is advantageous to include minor amounts of organic solvents i n the reac~ion `,
mixture, ~he presence of which facilitates contact of the reactants and promotes the reactlon ;
15 rate. One preferred class solvents are the monoalkyl ethers of the C2-4 alkylene glycols, ~vhich ; ~
includesthe monomethyl ether of ethylene glycol, the monobutyl ether of ethylene glycol, etc. . ~ ~.
When the dffired degree of reaion is reached, any excess nucleophilic compound can be
removed by standard methods, e.g., dia!ysis, vacuum strip,oing and steam distillation.
~"'`'.''.'~"`
The cationic, advanced epoxy resins of this invention in the form of aqueous
dis~e~ rsionsare useful as coating compositions, especially when applied by electrodeposition. ,
The coating compositions containing the cationic resins of this invention as the sole resinous
component could be used but it is preferred to include crosslinking agents in the coating ~ r;
composition, so that the coated films, when cured at elevated temperatures, will be crosslinked
25 and exhibit improved fllm Droperties Materials suitable for use as crossl inking agents are those .
known to react with hydroxyl groups or amino protons; and include blocked polyisocyanates;
amine-aldehyde resins such as melamine-formaldehyde, urea-formaldehyde, ben~ogucinine-
formaledyde, and their alkylated analogs; polyester resins, and phenol-aldehyde resins.
Preferred crosslinki ng agents are the blocked polyiso~yanates which, at elevated temperatures, ;~
30 deblock and form isocyanate groups which react with the hydroxyl grouDs of the resin to
crossiink the coating. Such crosslinkers are Drepared by reaction of the polyisocyanate with a
monofunctlsnal active-hydrogen compound. ExamDles of polyisocyanates and isocyanate~
functional preDolymers der~ved from ~olylsocyanates and oolyols using excess isocyanate
grou~s suitable for preparalion of t~le crossii nking agent are ~escrl bed i n U5 Palent 3 ,959,106
35 toBosso,etal.,InColumn15.Iines1-57.
The blocked Dolyisocyanate cross!inking agents are incorporated Into the coating ~ ~
composition at levels corresponding tO from 0.2 to 2.0 blocked isocyanate groups per hyaroxyl -~ ~ .
~ 9 ~ ~
.
.
WO 93/04104 2 1 ~ 4 7 ~ ~ P(~r/US92/07234
group of the cationic resin. The ~referred level is from 0.5 to 1.0 blocked isocyanatè group per
resin hydroxyl group. A catalyst optionally may be inciuded in the coating com,oosition to
provide faster or more complete curing of the coating. Preferable catalysts for the various ; -
classes of crosslinking agents are known to those skilled in the art. For the coating compositions ~;
using the blocked polyisocyanates as crosslinking agents, preferable catalysts include dibutyl ~:
tin dilaurate, dibutyl tin diacetate, dibutyl tin oxide, stannous octanoate, and other urethane-
forming catalysts known in the art. Preferably the catalyst is used i n amounts from 0.1 to 3 ;
weight percent of binder solids. Unpigmented coating compositions are prepared by blending
the cationic resinous product with the crosslinking agent and optionalIy any additives such as ~ ~ -
10 catalysts, solvents, surfaants, flow modifiers, and defoamers. This mixture is then dispersed in
water by any of the known methods~ The solids content of the aqueous dispersion is usually
from 5 to 30 percent by weight, and preferably frorn 10 to 25 percent by weight for application
by electrodeposition. ~:
Pigmented coating compositions are prepared by adding a concentrated .
dispersion of pigments and extenders to the unpigmented coating compositions. This pigment
dispersion is prepared by grinding the pigments together with a suitable pigment grinding
vehicle in~a suitable mill as known i n the art. ~igments and extenders known in the art are
useful in thffe coatings, and include pigments which increase the corrosion resistance of the
20 coatings. E~xarnples of useful pigrments or extenders include titanium dioxide, talc, clay, lead
o~ude, lead silicates, lead chromates, carbon black, strontium chromate, and barium sulfate.
The pH andlor conductivity of the coating compositions may be adjusted to ~
desired levels by the addition of compatible acids, bases, and/or electrolytes known iri the art. ~;
25 Other add;ti~ves such as solvents, surfactants, defoamers, anti-oxidants, bactericides, etc. may
also be added to miodify or optimize properties of the compositions or the coating in
accordance with practices known to those skilled in the art.
The coating compositions of the invention may be applied by cathodic : ~:
30 electrodeposition, wherein the article to be coated is immersed in the coating composition as
the cathode, with a sultable anode in contact with the coating composition. When sufficlent
vloltage is applied, a film of the coating deposits on the cathode and adheres to the article to be
coated. Voltage applied is preferably from 10 to l ,000 volts, more ~referably from 50 to 500
volts. The film thickness achieved increases wlth increasing voltage. Thicker films are achieveà
35 by incorporatlon of the diglycidyl ether of DolyDutyiene glycol into the r ackbone of ~he :,
catlonic res~ns of the invemion. Control over the final thickness may be excerclsed by aclj usting
the amount of that component used. The voitage is applied for between a few seconds to
several minutes, preferably frorn ~wo rinu~es over which time the current usuaily aecreases as
. ~
~ . 20- : `
. .
- ~
WC~ 93~04104 2 1 1 ~ 7 ~ 5 PCI/US92/07234
a resistive film is deposlted. Any electrically conductive substrate may be coated in this fashion,
especially metals such as steel and aluminium. Otner aspects of the electrodeposition process
are conventional. After deposition, the article is removed from the bath and rinsed with water
to remove that coating composition which does not adhere. The uncured coating on the article
iscuredbyheatingatelevatedtemperatures,preferablyrangingfrom 100to200C,for
periods of preferably from 1 to 60 minutes.
In another embodiment the flexibilized advanced epoxy resins may be flaked or
ground according to known processes and combined with epoxy curing agents and exposed to
10 conditions such that continuous films are formed, without conversion to cationic species.
Processesforpreparingsuchpowdercoatingsaregenerallywell knowntothoseskilled inthe
art.
In another embodi ment the flexibi lized advanced epoxy resi ns of this i nventi on
15 can be used in solvent coatings. In such an embodimentthe flexibilized advanced epoxy resins -
and a curing agent can be dissolved in a solvent and such mixture can be coated onto a
substrate and exposed to curing conditions. Preferred solvents are alkyl substituted ben2enes, ~ .
ketones, lower alkanols, glycol ethers, chlorinated alkanes, and dimethyl formamide. The
preferred solids level is from 25 to 80 % by weight; and preferably from 30 to 60 % by weight.
20 Generally curing conditions cornprise exposing the coated substituted to temperatures from 20
to ~50C under conditions such that the solvents can be removed from the coating.
The ~lexibilized advanced epoxy resins of this invention are cured with known
curing agents for epoxy resins. In preparing coatin~s the flexiblized epoxy resin compositions
25 are contacted with curing agents and the mixture is applied in a known manner to a substrate
such that the flexibilized advanced epoxy resins are cured to form coatings. Curing agents
useful in this invention are those compounds known to the skilled artisan to react with
polyepoxides or adYanced epoxy resi ns to form hardened fi nal products and which function to
cure the epoxy resi n.
The polyhydroxy comDounds described herei nbefore wherei n the hydroxy
rnoieties are bound to aromatic moleties are among suitable curmg agents. The novolac r~ased
compounds and the bisphenolic ComF)ounds are the ~referred polyhydroxy com~ounds ;or use
as curing agents. Examples of other Dreferable curing agents :nclu~e the r~olybasic acicis and
35 their anhydrides; other types of aclds containing sul fur, nitrogen, unospnorus or naiogens;
soluble adducts of amlnes and polyepoxides and thei r salts, SUCh as descri bed i n US 2 65 t, 589
and US 2,640,037; acetone soluble reaction products of polyamines and monoepoxides: ~he
acetone soluble reacti on prod UCIS O; poiyami nes wlth unsatu rated ?ilri I es;; m Idazol ne
2t~
W O 93~04104 ~ 1 1 4 7 ~ ~ - PC~r/US92/07234
com~ounds obtained by reacting monocarboyxlic acias with polyamines; sulfur and/or
phosphorus-containing polyamlnes obtained by reacting a mercaptan or phosphine containing
active hydrogen with an epoxide halide to form a halohydrin, dehydrochlorinating and then
reacting the resulting product with a polyamine; soluble reaction product of polyamines with
5 acrylate; and many other types of reaction products of the amines; boron trifluoride and
complexes of boron trifl uoride with amines, ethers, phenols and the like; Friedel-Crafts metal
salts, such as aluminum chloride, ~inc chloride, and other salts, such as zinc fluorborate,
magnesium perchlorate and ~inc fluosilicate; inorganic acids such as phosphoric acid and
partial esters thereof including n-butyl orthothiophosphate, diethyl orthophosphate and
10 hexaethyltetraphosphate; polyamides containing active amino and/or carboxyl groups, and
preferably those containing a plurality of amino hydrogen atoms, especially preferred ~ ;
polyamidesarethosederivedfromthealiphaticpolyamidescontainingnomorethan 12
carbon atoms and ~olymeric fatty acids obtained by dimerizing and/or trimerizing ethylenically
unsaturated fatty acids containing up tO 25 carbon atoms; and melamlne reaction products
15 containing methylol substituents.
' ~
Preferred classes of curing agents are the polyamines and amides. Such Dreferred ` .
curing agents include aliphatic polyamines, polyglycoldiamines, polyoxypropylene diamines,
poiyoxypropylenetriamines, amidoamines, imida~olines, reactive polyamides, ketimines,
2 a araliphatic polyamines (i.e. xylylenediamine), cycloalipihatic amines ~i.e. isphoronediamine or
diaminocyclohexane) menthane diamine, 3,3-dimethyl-4,4-diamin~dicyclohexylmethane,
heterocyclic amines ~aminoethyl piperazine), aromatic polyamines, (methylene dianiline), ~.
d~aminodiphenyl sulfone, mannich base, phenalkamine, N,N'N"-tris(~amlnohexyl) melamine, -.
and the like. Most preferred are cyanamide, dkyandiamide, and its derivatives,
25 diaminodiiphenyl sulphone and methylene dianiline.
The flexibili~ed advanced epoxy resin tompositions of this in~ention are
contacted with sufficient curing agents to cure the resin. Preferably the ratio of epoxy (glycidyl
ether~ eQuivalents to equivalents of curing agent is from 0.5: l to 2: 1; more Dreferably from
30 0 6: l .4 to 1.4: 0.6; even more preferably from 0.8: 1.2 to 1.2: 0.8 and most ~referably from
0.9: l.ltol.l :O.g.
The coatings of this invention aemonstrate excellent adheslon, resistance to
cathodic disDondment. excellent flexibility and imDact reslstance, goo~ comDatibiiity wlth a
35 widevarietyofreslnous~inders,suchasacryiics,alkyds,polyestersaswellascurlngagentslike
polyamines, melamine or Dnenol resins.
-22-
:
`:"
.
WO 93/04104 2 1 1 ~ 7 ~ ~ PCr/US92/07234
The following examDles are included for illustratlve purposes only and do not
limit the scope of the claims, Unless otherwlse stated all parts and percentages are by weigh~, ....
EXAMPLE l - Reaction of polypropylene glycol diglycidyl ether, bisDhenol A and diglycidyl ether -':
of bisphenol A. :,~,. .
Not an example of the invention. : -
To a to a 51 glass reactor are charged 1550.4 g of a diglycidyl ether of bisphenol A
having an EEW of 1$7.0 (8.33 epoxy eq), 618.0 g of a diglycidyl ether of polypropylene glycol ~ -
(EEW of 334.0) prepared from a polypropylene glycol having a molecular weight of 425 (1.85 ' ,~ ~
epoxy equivalents~ and 831.6 g of bisphenol A (7.29 eq of phenolic hydroxyl). The mixture is ~ :
heated to 100C and 2.9 g of alkyltriphenyi phosphonium càtalyst is added. The reactor is slowly ~ -'
heatedtol40C.At 140Cthereactionmixtureexothermsandthetemperaturerisestol60C. .
Thetemperatureismaintainedatl60Cfor60minutesatwhichtlmeasampleofthereaction '~
15 mixture is taken which demonsuates an EEW of greater than 1000. The reaction is quenched by ~: ~
cooling. The resulting resin is crushed and stored. The final epoxy equivalent weight is 1059. ,' '.',
' '`
~ .
~ .
,~
-23- .
WO 93/04104 2 1 1'~ 7 9 ~ Pcr/uss2/o723~ ~
The solid resin is converted into a water-dispersed form usable for the
formulation of cathodic electrodeposition primers ~y following procedure. In a reactor 620 g of
5 the solid resin is dissolved in a mixture of 34.4 g xylene and 34.4 g Dowanol~ PPh glycol ether,
the phenyl ether of propyiene glycol at a temperature of 11 0C 467.4 g of a 70 wt % solution
of blocked polymeric methylene diisocyanate crosslinker in methyl isobutyl ketone is ~lended
with the resin solution. Then 40.7 9 of a 73 wt % solution in methylisobutylketone of the
diketimine of methyl isobutylketone and diethylenetriamine is added, followed by 3~.1 g of
10 methylethanolamine. The reactor is cooled to keep the reaction temperature from rising over
110C.Atemperatureof 110Cismaintainedfor60minutes.Then38.3gof Dowanol~ PPh
glycol ether is added to the reactor. A second reactor is now prepared containing a mixture of a
1306 9 of deionized water, 39.3 9 of lactic acid (0.31 eq. of acid) as well as 17.2 9 of a mixture of
suitable cationic surfactant and defoamer. Under strong stirring the hot resin mixture is slowly
15 poured into the second reactor, whereby a low viscosity dispersion is obtai ned. The dispersion is
diluted further by the addition of 637.0 9 of deionized water. The dispersion is heated to 65C,
after which the volatile organic solvents are stripped off over 2 hours by distillation at a
reduced pressure of 250 mbar. The solids content of the dispersion, after 1 hour drying at
1 50C, is determined to be 36.40 % . The dispersion is mixed with a commercially available .
20 pigment paste and diluted by addition of deionized water so that the final
Pigmented dispersion has a O.3: 1 ratio of pigment to binder at a solids content of 20 wt % . ~ ;
'::
EXAMPLE 2 - Reaction of diglycidyl ether of polypropylene glycol with bisphenol A and
subs~quent reaction of the product with diglycidyl ether of bisphenol A
25 Not an Example of the Invention.
To a reanor similar tO the one described in Example 1 is charged 618.1 g of the
diglycidyl ether of polypropylene glycol described in xample 1 and 831.6 9 of bisphenol A
(7.24 eq of phenolic hydroxyl). The mixture is heated to 1û0C and 2.9 g of
30 al kyltri~henyl phosphonium catalyst is added . The reactor is slowly heated to 1 50DC ( 1 to 2C Der
mlnute). At 1 50C an exotherm begins and the reaction temperature increases to 1 60C The
temoerature is maintained at 160C untiI the welght percentageof eDoxy in the mlxture Is ess
than 0.1 Darts by weight: about 60 minutes~ To the reaction mixture is added 1550 4 g of the
diglycidyl ether of bisphenol A descrlbed in ExamDle 1 (8.33 eooxy equivalents). The
~ Trademark of The Dow Chemical Company
-24-
WO 93/04104 2 1 1 4 7 ~ ~ PCI/US92/07234
temperature drops to 1 10C as a result of this addition. The mixture is mixed for 5 minutes and
then the temperature is slowly raised by heating ( 1 to 2C per minute). At 140C an exotherm
begins and the temperature rises to 1 70C. Tne temperature is reduced with cooling to 1 60C at
which temperature the reaction mixture is maintained until a sample removed shows the resin
has an epoxy equivalent weight of more than 1000. The reaction is quenched by cooling, and
theresuitingsolidresinhasanEEWof lO99.AnaqueousdispersionispreparedasdescribedinExample 1, the amount of amine added is 95 % of the epoxy equivalents, and the amount of
10 lactic acid is adjusted to reach the same neutralization level.
EXAMPLE 3 - Reaction of diglycidyl ether of polyprooylene glycol with bisphenol A and '
subsequent reaction of the product with digiycidyl ether of bisphenol A ~ `
Not an Example of the In~ention. ` `~ -
1 5 ' '~- ." ` '
Example 2 is repeated usi ng 620.0 9 of the diglycidyl ether of polypro~ylene
glycol (EEW 317.7) prepared from a polypropylene glycol of MW 390, 571.0 g of bisDhenol A ;
and 2.9 9 of alkyltriphenylphosphonium catalyst. The mixture is heated to 1 00C. The reactor Is
then slowly heated to 1 50C (1 to 2C per minute).To the reaction mixture is added 1543.8 9 of
20 the dig!ycidyl ether of bisphenol A described ;n Example 1 (8.33 epoxy equivalents) ~!~e
te-nperature drops to t 10C as a result of this addition. The mixture is mixed for 5 millutes and
then the temperature is slowly raised by heating (1 to 2C per minute). At 140~C an exotherm
begins and the temperature rises to 1 70C. The temperature is reduced with cool;ng tO 1 60C at
which temperature the reaction mixture is maintained until a sample removed shows the resin
~ r
'' hasanepoxyequivalentweight~fmorethan1000.Thereactionisquenchedbycooling,and `~``r.;
the resulting solid resin iscrushed and stored. The EEW is 1082. An aqueous dispersion is
prepared as described in Examples 1 and 2.
,
EXAMPLF 4 - Reactir~n of diglycidyl ether of polybutylene glycol and bisphenol A and
30 sùbsequent reaction with the diglycidyl ether of bisDhenol A -
Example 3 is repeated with 4t2.2 9 of a diglycidyl ether of a polybutylene glycol
~EW 250.0), wherein the Dolybutylene glycol MW ~number average) is 300; 583.8 9 of ~^
bisphenol A, and 2.0 9 of catalyst as described in ~amoie 1 t takes about 90 minuxtes until the
~eignt percenlage of epoxy ~n the mixture Is less than 0 1. To the ~eactor i5 added 1004 9 g of
~`~
-25
~"3 :'S ;~
2l~ ~7~'
the liquid epoxy resin described in Example 1. The resulting solid resin has al ~EW of 1 Q90. A
water dispersion is p-epared as dffcribed in Ex~mples 1 and 2.
;
EXAMPL~ S - Reaction of diglycidyl ether cf pdybutyl~ne glycol ant bisphenol A and
subsequent reaction with diglycidyl bispi~enoI A
Example 3 i~ repea~ed with 41~.2 9 of a dic~lyciayl ether of a polybutylene glycol . :~
(~tW367.0),v~hereintheMW(number~Jerage)o~thepQly~utylene~lycolprecurso~is550
0 546.5 9 of bisphe~ol A, and 2.0 g of catalyst as ~es~rib~d ;n Exarnple ~ . It takes about 6û
m~nutes until the weight pQr~Qntage ~f epoxy in the rnixture is less than û. t . To the reac~or is
added l 042.2 9 r~f the liquid epoxy -esin d-Kribed in E~ample 1. The EEW o~ the resulting resin : S :~
is 1087. An aqueous disp~rsion iS prepared asdescribed in Examples 1 and 2.
I he dispersions of Fxampl~s 1 ~o S are tested ~or pH and conductivity. The resu~
are co~npiled in r~b
Table I -
.. ~ .
t~. e.. mple Oxide Ae c~on pH uSJcm!~ : ~
_ _ _ _ ~ ,
~ 1~ ~ propylene oxide .1 step 6.~ 1490 . ~ .
. ~ ~: . ~; ~ : _ ~,
2~ : ~ propylene oxide 2 step 6.2 1360 `
: 3~ ~ ~propyleneoxite 2step~ 60 lao
25~ ~4 ~ ~ ~ butyleneoxide2step 6.3 1154
S ~Oylene ~ e 2 step 6.2 1254 :~
. . . _
k Not a~ exa~ple o~ tne ln~en~lon
** MicrD~ie~ens / ceD.time~er
EXAMPLES 2 to 5 - Cathodic Deposition of Coa~ings and Testing of Properties
Dispersions prep~red in Exa~nples 2 to ~ are separately deposited on Bonder 26
phosphatiieJ stee~ panels by electrod~positior, rins-d in deioni~ed water and baked at t 75C
for 20j minutes. Depositio~ conditions a. e chosen such that the coati ng has a thickn~ss of 25 : .
microns. The Crichsen Indentation test is performed to a ~first crack~ endpoin~ ~he Salt ~ath
corrosion test conditic ns ~r~ 500 hours of immersion in a 5 pe-cent st>dium chloride in wat~r -~:
35 so;ution at 55C The resultsare compiJed ;n Table 11.
....
26~ SIJ~ 5JTE SHE~
. . .
~ .
'
t
,j,
- . . `
. . ... .....
` .`:: `
WO 93/04104 2 ~ Pcr/US92/07234 . .
. .
~able II ~ ~
. . _. _ .. _ .... .
5 Example Erichsen mm mm Cleep Rev. Impact . .:
.
2 6.2 0.5-1.0 C 5
3 5.7 < 0.5 . ~`
4 7.6 ~ 0.5 10 :
1 o .. _ . . . _ ~ .
7.5 < 0.5 20 ~:
EXAMPLE 6 - Reaction of Diglycidyl ether of Bisphenol A, diclycidyl ether of polypropy!ene `
l S glycol~ and ~,
BispnenolA
Not an example of the invention ~
The following amounts of raw materials are charged into a 1 liter glass reactor: ~ ;
382.7 9 D.E.R.~ 331 epoxy resin (EEW = 186.9~, 200 9 of D.E.R.~ 732 epoxy resin, the diglycidyl
20 ether of a polypropylene glycol, (EEW = 318.5) and 217.3 9 of Bisphenol A. The mixture is
heated under stirring and a nitrogen purge tO 90C and then 0.71 9 of a trialkylphosphonium `
catalyst is added. The temperature is gradually increased. At 1 40C the exotherm begins and
the temperature increases to 180C. The temperature is then decreased with cooling to l 70C ~r~
-and maintained for 45 minutes, until a sample of the reactor contents shows an EEW of 1050.
The resin is cooled, crushed and stored.
The resulting resin is converted into an aqueous dispersion using the procedure `
described in Example 1, with the exceptions that the crosslinker is as described in US Patent
4,104,147,moreparticularly70wt%solutioninMlBKofan3:1:3adduct~basedonmolar ;
30 quantities)oftoiuenediisocyanate,trimethy!c -opaneandethylhexanol.Additionaliy, 10 9 of
dibutyltindilaurate cur~r~ calalyst is added t~ e resin crosslinker blend, just oefore aispersing
it into water.
Aftèr strioping, tne aisDerslon is dilutea tO 20 wt ?o solids and used for
35 eiectroae,oosltlng an unP~9mented coallng unto ~onder 26 panels and unto degreasea
untreated steel panels. The coat~ngs are cured for 20 mi nutes at l 90C. 3eDosition conr ltions
are cnosen in sucn a way thas the iinal film thickness of the cured films is 20 um.
: .',.`.,
:
W O 93J04104 2 ~ 3 P~r/US92/07234
EXAMPLE 7 - Reaction of Bisphenol A with diglycidyl ether of polypropylene glycol, and
5 subsequent reaction with Bisphenol A diglycidyl ether
Not an example of the invention
The following amounts of raw materials are charged into a 11 glass reactor: 200 9
of D.E.R.* 732epoxyresin,thediglycidyletherof polypropyleneglycol, (EEW= 318.5) and 217.3
g of bisphenol A. The mixture is heated under stirring and nitrogen purging to 90~C after which
10 0.71 9 of a trialkylphosphonium catalyst is added. The reaction mixture is gradually heated to ~,
170C, and maintained for 50 minutes until analysis of a sample of the reaction mixture shows
anepoxycontentlessthanO.l wt%.~87.2gof D.E.R.~ 331 epoxyresin(EEW- 186.9~are .-
added, causing a temperature drop to 110C, after which the mixture is reheated to 130C. The
exothermic e~fect of the continuing rea~tion raises the temperature to 170C. The reaction is
15 continued at that temperature for 20 minutes until analysis of the resin gives an EEW vaiue of
1072. The resin is cooled, crushed and stored.
The conversion into an aqueous dispersion, the electrodeposition of the resulting
clear coating and its curing are performed in the same way as described in Example 6.
EXAMP!E 8 - Reaction of diglycidyl ether of Bisphenol A diglycidyl ether of polypropylene
glycol and Bisphenol A
Not an exampl~ of the invention
Using the procedure as described in Example 5 a resih is prepared. The reactor is
25 charged with 389.2 9 of D.E.R.~ 331 epoxy resin,200.0 9 of the diglycidylether of a
polybutyleneglycol(EEW= 368.12)and210.8gofbisphenolA.TheresultingresinhasanEEW
of 1050.
Conversion into an aquec us dispersion, electrodeposition and curing are
30 performed in the same manner as described in Example 6, except for the amount of .
neutralizing acid, which is 5 % higher.
~ . .
EXAMPLE 9 - Reaction of Bisphenol A with diglycidyl ether of polybutylene glycol and
subsequent reaction wlth diglycidyl ether of BisDnenol A
'~ `
-28- ~ `
WO 93/04l04 2 1 1 ~ 7 9 ~ Pcr/us92/o7234
'':` ~.
~ .
Using the procedure described in Exam~le 6, 200 9 of the diglycidylether of a
polybutyleneglycol (EEW = 368.1 ) and 210.8 9 of bisphenol A are charged into the reactor and
5 the reaction proceeds. In the later stage of the reaction 389.2 g of D. E. R. ~ 331 epoxy resi n is
added. The resulting resin has an EEW of 1054. Conversion into an aqueous dispersion, ;
electrodeposition and curing are performed in the same way as described in Example 6, except
for the amount of neutralizing acid which is S % higher. .
Results of pH and conductivities of the clear dispersions of Examples 6-9 at 20 wt
% solids are listed in ~ ~le lll. Results of reverse impact, Erichsen tndentation, Salt Bath `~ -~
immersion test and sc~ . ;pray are also listed. The salt spray test is performed according to ASTM `
B 117 for 300 hours on degreased untreated steel panels coated with the ~ured panels. Tests
performed on the cured clear coatings are shown in Table IV.
Table III
......... "': .
Example Oxide Type ~rocedore pH Conductivity :
6* ~~: propyleneoxide 1step 6.6 1790
_ . ... _.. _ . r
20 7* ~ propylene oxide 2 step 6 4 1850
:8~ : butyleneoxide 1 step 6.2 1660
^ 9~ ~ butylene oxide 2 step 6 0 1484
Not an example o the inven ion ~ ~ _
** Microsiemen~slcentimeter
Table IV
,,, .~
act ¦ Erichsen ¦ Immersion ¦
6* 116 8.8 3.2
, . . . -
7* > 160 9.1 2.0 4.5
~ , . _ . . . . _
.` 8* 100 8.7 3.5
, _ _, . . . ..
9 i 160 9.2 1 .0 2.0
Not an example Ot the inventlon
'~` ''"'`'
-~.
: ~.
W O 93/04104 2 1 14 ~ PC~r/US92/07234
~.,.
EXAMPLE 10 - Reaction of diglycidyl ether of polybutylene glycol with bisphenol A and
subsequent reaction of the product with diglycidyl ether of bisphenol A and additional
5 bisphenol A.
325 9 (0.897 epoxy eq) of the diglycidyl ether of a 550 Mw polybutylene glycol
and 408.5 g of bispenol A (3.583 eq of phenolic Ol 1) are charged to a 5 liter reactor. A gentle
nitrogen purge is started over the contents and the temperature is raised at a rate between 1
. and 2 degrees C per minute while contents are stirred. When the reactor temperature reaches
10 120C, l .1 9 of alkyltriphenyl phosphonium catalyst are added. Heating of the reactor is
continued until a rnild exotherm is observed to begin at around 1 50C, at which time the : .
external heating is discontinued. Once the exotherm finishes and the temperature returns
again to 160C, 3,240.1 9 of a diglycidyl ether of bisphenol A having an EEW of 178 and an
additional 1026.4 grams of bisphenol A are charged to the reactor. The temperature is again
raised at a rate of between 1 and 2 degrees C per minute. At 1 00C, and an additional 2.4 '~
grams of alkyltriphenyl phosphonium caealyst are added. Heating is continued until the~ ~ ~
beginning of an exotherm is obseNed. At this point ehe external heating is again discontinued. ~ '`
After exotherm cool-down, and flaking, the epoxy is analy~ed and found to have an EEW of
- 759.7, a Mètler solftening point of 89.4C, and a melt viscosiey of 1.81 Pa.s at 150 C.
EXAMPLE~ Preparation, application and testlng of a powder coating
840.4gramsof the flaked resin of E)tAMPLE 10, 259.6grams of D.E.H. 81
(commercially available phenolic OH functionaî hardener commonly used in pipe and
functional powder coatings), 600 grams of TiO2, 200 grams of BaSO4, and 100 grams of CaCO~
25 - are~ premixed mechanically in a lab mixer for 3 minutes at 600 RPM. This dry mix is then ~ ``
completely meit- homogeni~ed by feeding it through a ZSK 30 twin screw laboratory extruder `
at a temperature of 90C and a screw speed of 300 RPM. The e~trudate is cooled by passing it
between two water cooled rolls and the resulting sheet is then flaked. The flakes are ground
on a lab grinder until 100% will passthrough a 100 micron screen. This final powdet is bagged
30 and kept cool and dry.
6 mm thick cold rolled steel panels are cut to nominal dimenslons of 150 by 70
mm. The finished test panels are degreased with acetone, glass blasted to an average profile of ~:
10 microns, and promptly placed in a c~rculating air oven which has been set to 235QC. After
Dreheating for 20 minutes, the Daneis are removed from the oven and hung in a sDray booth.
35 The panels a~e electrostatically sprayed to an e5timated thlckness of 350 mlcrons wilh the `
oowcier coat!ng. After coating the paneis are returned to the 235 deQree oven for a l minute .
30.
:, ~ : .. `
WO 93/04104 2 1 1 ~ 7 ~ ~ PCI /US92/07234 ~
post cure, after which they are quenched by immersion in cold water. The resulting coatings
are hard and glossy.
, .
The flexibi I ity of the coating is tested by bending the coated panels around an 18
mmdiametermandrel inaccordancewithDlN35571 flexibilitytest. 10panelspreparedas
described and at an average coating thickness of 347 microns are found to tolerate a 36.5 ~`
degree flex before cracking. This is considered to be excellent flexibility.
:~
EXAMPLE 12 - Reaction of diglycidyl ether of polybutylene glycol with bisphenol A and
subsequent reaction of the produ~t with diglycidyl ether of bisphenol A.
404.1 grarns ~ 1.609 eRoxy eq) of the diglycdyl ether of the 330 Mw poly~utyleneglycol and 494.6 grams of bisphenol A (4.338 phenolic OH eq) are charged to a 2 liter reactor. A ; -~
15 gentle nitrogen purge is started over the contents and the temperature is raised at a rate
between 1 and 2 degrees C per minute while contents are stirred. When the reactor
temperature reaches 120C, l gram of alkyltriphenyl phosphonium catalys~ is added rieati ng
of the reactor is continued until a mild exotherm is observed to begi n at araund 150C, at which
time the extern. leating is discontinued. Once the exotherm finishes and the temperature
20 returns again to 160C,601.4 9 (3.36 epoxy eq) of diglycidyl ether of bisphenol A with EEW of
178.6 are charged to the reactor. The reactor is agai n heated at a rate of 1 to 2 degrees per
mi nute um: i the temperature reaches 120C at which point an additional 1.65 grams of
alkytriphenyl phosphoniurn catalyst are added. Heating of the reactor is continued until an
exotherm is observed at around 150 degrees. At this point the external heating is discontinued
25 until the reactor temperature falls again to 150~C. Reactor is then maintained at 150 until the
EEW is found to exceed 2800. The advanced resin is poured from the reactor into an aluminum
foil tray and allowed to cool to room temperature. The Metler Softening Point is determined
tobe 104.1Candthesolutionviscosityat40wt% solidsindiethyleneglycol monoblJtylether
Is meas~ eci to be l 914 cSt.
EXAMPLE 13 - Formulation application, and testing as a can coating
80 grams of the advanced resin of EXAMPLE 12 are dissolved i n l 50 grams of a
soivent biena consisting of 50 Darts Dowanol PMA, 10 Darts of 2-butanol and 40 parts of
Solvesso 100. '0 grams ~soiids) each of Phenodur PR 285 and Bakelite '00 kommerclal vhenolic
35 reSoie crosslinkers) are added to the advanced resln solution. l ~ram (soiid) of Dhos~horic acid
s added to accelerate the cure. The formulation is ailowed to age for 24 hours at 40C and is
-31 - -:
WO 93/04104 ~ 7 ~ ~, PCTtUS92/072~
then reduced with the solvent blend described above until a ASTM D445 viscosity of 250 mPa.s : :
is reached. The soiids content is measured to be 38 wt % .
~ .
The formulation is applied using a wire wrapped draw down rod to a 0.235 mm
thick sheets of Ancrolyt tin free steel and Androlyt ti n plate (both available from Rasselstei n
AG) which have been degreased by rinsing with acetone. A wet application of between 20 to
- 40 microns is chosen such thatdry film thickness of 5 to 6 microns is obtained. The coated tin .
plate panels are placed in a circulating air oven preheated to 200C for a cure time of 10
minutes. The coated tin free steel panels are cure at 280 for 28 seconds.
..'; ~:-
To test the performance of the coati ngs, 2 cm high asymmetric cans with 5, 10, 1 5, ~ -:
and 20 mm radi us corners were drawn from the coated tin free steel and ti n plate sheets. In `
15 each case, perfect coa~ing integrity on all corners and edges is maintained throughout the - ~
drawing process. The drawn cans are further tested by exposi ng them to water at 1 29C. The ~ : -
exposuretimeis30minutesforthetinplatecansand90minutesforthetinfreesteelcans. In
each case, the integrity of the coating is maintained during the exposure and no blushing or
blistering is observed. ~ -
-32- :~
