Note: Descriptions are shown in the official language in which they were submitted.
The present invention is directed ~o improved coating composi-
tions based on heat-hardenable binder systems which are water dilwtable
on partial or total neutrali7ation of their basic groups with acids. These
coating compositions are particularly suited for cathodic deposition in an
electrodeposition coating process~
Canadian application Serial No. 297,182 filed February 17, 1978
discloses cathodically depositable water-dilutable coating compositions
wherein a basic binder system is utilized which includes acid groups, the
ratio between the basic and acid groups as reflected by the ratio of amine
value to acid value, in mg KOH/g, ranges between 97 : 3 and 65 : 35. The
acid and basic groups are either attached to the same macromolecule or to
separate macromolecules in the basic binder system. The coating composi-
tions optionally includes pigments, dyestuffs, extenders, solvents, paint
additives, and additional crosslinkers. The advantages provided by the acid
groups in the basic coating compositions include better crosslinking density
of the cured film and reduced curing temperatures of the coating in relation
to basic binders without acid groups.
It has now been found that the properties of the coating compositions
of application Serial No. 297,182 can be further improved provided at least
one of the components of the basic binder system is modiied by a partially
blocked polyisocyanate. Accordingly, the present invention is specifically
directed to cathodically depositable water dilutable coating compositions
based on binder systems containing basic nitrogen groups and, in addition to
the basic nitrogen groups, acid groups in a ratio as expressed by the ratio of
.
:
~ ,
~13~;3~
amine valuc to acid valu~, in mg K~ll/g, ranging between 97 : 3 and 65 : 35,
and wherein ther0 is present in ~he coating composition at least one resin
component which is modified with a compouncl of th~ general formula -
OCN - R j NH - CO - R']
wherein:
n is 1 - 3;
R is an aliphatic hydrocarbon radical, or an aromatic or cycloaliphatic
nucleus, preferably substituted with alkyl groups, and
R' is the moiety of a saturated or unsaturated alcohol; a phenol optionally
substituted with alkyl radicals; a cyclic lactam; an aldoxime, a
ketoxime; an acetoacetic acid ester, or a hydroxamic acid ester.
The coatings can optionally include pigments, dyestuffs, extenders, solvents,
paint additives, and additional cross-linking components. The coatings of
the present invention have better throwing power, which means that the deposi-
tion of th~ paint is greatly enhanced on areas remote or shielded from the
anode with respect to the coating systems of Serial No. 297,182. Further-
more, sensitivity to still clinging aqueous paint or rinse water, or impuri-
ties of the deposited dry film is considerably reduced, which in turn leads
to excellent cured films. Another advantage of the same coating is enhance-
ment of the corrosion resistance of the coatings.
Binder systems particularly suitable for the modification according
to the present invention are those which include more than one macromolecular
component with at least one component carrying basic groups. Preferably,
however, all of the main components will carry basic groups. At least one
of the components will carry acid groups. A variety o raw materials are
": .
~L3t~3~
l~nown which can be used lo synthesir~e ~he rnacromc)lecule,s carrying the
basic groups. The Eollowing includes a deseription of various methods of
synthesiz;ng the macromolecules which is exemplary and not complete:
-1~ preferred group of macromolecules wLth basic nitrogen atoms
is formecl by adclition reaction oF epoxy compounds with secondary amines.
lllustrative epoxy group containing raw materials having in eommon the gen-
eral formula
- CE~ - CE~ ~ R, wherein R is H or alkyl
are glyeidyl ethers of phenols, particularly of 4,4'-bis(hydroxyphenyl)pro-
pane (Bisphenol A); glycidyl ethers oE phenol formaldehyde condensates of
the Novolak type; glyeidyl esters of aliphatic, aromatic, or eyeloaliphatie
mono- or polyearboxylic acids; glycidyl ethers of aIiphatic or cycloaliphatic
diols or polyols; eopolymers of glycidyl~meth)acrylate, and epoxidation .
products of aliphatic or cyeloaliphatie di- or polyolefinesO A more eomplete
survey of epoxy group eontaining raw materials is found in A. M. Paquin
"Epoxidverbindungen und Epoxyharze, " Springer 1958. Seeondary amines
suitable for addition to the epoxy group containing raw materials inelude
dimethylamine, diethylamine or higher homologues or isomers thereof.
Secondary alkanol amines are particularly suited, ineluding diethanolamine9
diisopropanolamine, or higher homologues or isomers thereoe. Cyclic
secondary amines sueh as ethylene imine, morpholine, ancl piperidine can
also be employed. The reaction of the epoxides with primary/tertiary or
secondary/secondary diamines leads to compounds with cationic character.
It is evident that the epoxy eompounds can be modified with other eompounds
such as mono~ or diearboxylie aeids. It is essential that the produets earry
.
, . . ~ . . .
.
L363q~
a sut`ficierlt number Or ba~sic gro~lps to cnabLe acccptable dilution with waterupon partial neutralization with acids.
- Macromolecules with basic nitrogen atoms are also obtained
through copolymerization of suitable basic monomers with hydroY~yalkyl-
(meth)acrylates, pre~erably in the presence Oe other copolymeriY,able com-
pounds. Such basic monomers inc:lude the (meth)acrylates, such as N,:~-
dimethylaminoethyl(meth)acrylate; vinyl piridine; N-vinylirnidazoL, and
N-vinylcarbazol. The basic group containing monomers can be copoly-
merized with other monomers including hydroxyalkyl(meth~acrylates; other
(meth)acrylates, i. e., those not containing basic nitrogen groups; (meth)-
acrylamides; vinyl aromatics such as styrene9 vinyltoluol, and alpha-methyl
styrene .
- A further group of macromolecules with basic nitrogen atoms
are the substituted oxazolines including those obtained by the cyclizing con-
densation of amine alcohols, such as trishydroxymethyl aminomethane or
2 -amino-2 -hydroxymethyl-1, 3-propanediol, with aliphatic carboxylic acids
or carboxy group containing macromolecules. A comprehensive survey of
useful oxazolines is set forth by J. A. Frump, Chemical Review, 1971~ Vol.
71, No. 5, pp. a~83 - 505. Polyesters with the substituted o~azoline groups
are disclosed in U.S. Patent No~. 3, 882,188 and in British Patent No.
1,411,568.
- A further group of macromolecules with basic nitrogen atoms
is obtained by addition reaction of anhydride group containing compounds
with alkanol amines, particularly with dialkylalkanolamines, e. g. 9 dimethyl-
or diethylethanolamine. The addition reaction is carried out at from 50 to
150 C., preferably 90 - 120C., with semi-ester formation. Suitable
-- 6 --
~.~Li363(:~
stL~ting materials a~e succinic anhydride derivatives or Diels~Alder ad-
ducts as c:an, Eor e~ample, be obtained by addition oE maleic arlhydride to
compo~u;lcls with isolated or corljugated double bonds. ~mong this group are,
for example, adducts of maleic culhydricle to unsaturated oils and fatty
acids, and rosin acids to diene polymers, unsaturated hyclrocarbon resins,
and the like~ E~urthermore, copolymers carrying anhydride structures,
such as styrene-maleic anhydride copolymers, can be employed, Nitrogen
groups can also be introduced into the macromolecule by the reaction of
acid anhydride groups or semiesters thereof with diamines carrying one
primary and one tertiary nitrogen atom and is a particularly favorable
method where one of the components includes a macromolecule into which
the basic groups are introduced through condensation of dicarboxylic acid
anhydrides with primary/tertiary diamines, with the formation of water.
Suitable starting materials are the succinic anhydride derivatives above
noted or Diels-Alder adducts or copolymers. Oligomeric liquid polymers
of dienes are particularly preferred for adduct formation, especially of
1, 3-butadiene. The quantity of added dicarboxylic anhydride usually lies
between 10 to 25 percent by weight. The adduct anhydrides are as men-
tioned partially reac$ed with primary/tertiary diamines with water being
formed and thereby introducing tertiary basic nitrogen atoms in addition
to amide and imide groups. The quantity of diamine compound is chosen
in order that for one mole of anhydride group about 0. 3 - 0. 8 moles of
diamine are used. A residual quantity of carbo~y groups is provided as a
precaution, which subsequently is set free from the latent form of the
residual anhydride groups through reaction with water or monoalcohols.
Examples of suitable diamines are dimethylaminoethylamine, diethylamino-
ethylamine~ dimethylaminopropylamine, diethylaminoprop~lamine and
-- 7 --
~363~
ilornologl:les tile]~cof. 'L'~-le diarr~ e i,s ackle(l at between 50"C, arld 1~0 C.
The reaction is finished at between 160 and 220~ C., the formation of the
preferred acid imide group being traceable ~Nith the quantity of the water
formed or with magnelic nuclel:ls resonance spectroscopy. At lower reac-
tion temperatures the ~orrnation o:~ an a.cid a.mide group is tra.ceable only bynucleus resonance measur ement. rrhe further component of this particularly
favorable method pr eferably are reaction product,s of epoxy group containing
compounds, particularly of polyglycidyl ether s of polyvalent phenols, such
as Bisphenol ~, or of Novolak resins with secondary amines. Suitable epoxy
compounds also are polymers carrying epoxy groups, based on dienes or
acrylic copolymers. In acldition to the secondary aliphatic or cycloaliphatic
amines generally used, a derivative of diethylene triamine can be used, both
primary amino functions of which are masked through ketoimine fo~mation
with at least 2 moles of ketone, The addition of the secondary amlne or
alkanolamine to the epoxy resin is carried out at a temperature between 30
to 150 C., and is generally an exothermic reaction. In case of the preferred
epoxy resins melting at higher temperatures, it is advantageous to coemploy
solvents inert to the epoxy groups, secondary amines, and hydroxy groups.
Such solvents include ketones, such as methylethylketone and methyliso-
butylketone; esters, such as ethylaceta.te, butylacetate, and ethylglycol
acetate; ethers, such as tetrahydrofurane, ethylene glycol diethyl ether,
and the like. The quantity of secondary amine or alkanol amine is chosen
in order that the reaction pr oduct has an amine number o~ between 35 and
120 mg KOH/g. In general this value is attained, even if not all epoxy
groups are consumed~in the reacti.on with the amine compound, In this case
it is of advantage to esterify the remaining hydroxy groups with satura.ted
~3630
or unsaturated carbo~ylic acids. In copenc1ing appLication Serial No.
816, 937 deposited July l~l, 1977, methods of introducing basic grc~ups into
macromolecules by reacting hydroxy or carhoxy group containing com-
pounds with basic monoisocyanates are described.
Various methods are known for introducing acid g~roups into the
binder system. It is possible to admix a suitable quantity of a macromole~
cular compound carrying acid groups with a basic resin~ Alternatively7 a
chemical combination between the basic and acid components can be effected
through reaction of an acidic macromolecular compound, or an intermediate
compound, with a basic resin. The acid compounds used according to this
method are prepared in a separate reaction step~ A preEerred group of
-- macromolecular compounds are the addition compounds obtained through
reaction of ~lpha, beta-unsaturated dicarboxylic acids or anhydrides with
compounds having isolated or conjugated double bonds (adducts), In case of
adduct formation with anhydrides, it is necessary to open the anhydride ring
with water or alcohols and to thereby set Eree th0 carboxy groups.- Starting
materials for such adducts are unsaturated oil Patty acids, synthetic or
natural hydroxy-free esters, mixed esters thereof with rosin acids, as well
as diene polymers or hydrocarbon resins.
A still further group of macromolecular compounds with acidic
character are the conventional polyesters or alkyd resins selected to carry
a sufficient number of free carboxy groups. The required acidic character
is achieved either by interrupting the esterieication at the desired acid value
or by the formation o partial esters of di- or polycarbogSrlic acids with
hydroxy-rich polyesters with low acid values. Furthermore, according to
the present invent;on, copolymers can be coemployed which carry free
63~
carboxy groups. I1he ~ crerre(1 c opolymers arc those with acrylic or
vinyl~lromatic structur~s> e.g., copolymers oL` acrylates, styrene., acrylic
acicl, methacrylic acic1, maleic acid derivati~/es, etc.
The acid components, in adclition to the essential acid grvup.s~may
contain other functional groups, suc:h as hydroxyl groups, a-mide groups,
imine groups and amine groups. If these aclditional groups are of basic
nature, they must be considerecl when calculating the desired ratio in the
binder of the basic and acid groups.
The ratio between the basic and acid groups in the binder sS~stem
is expressed as the ratio between amine number and acid number (mg KOH/g)~
The coating compositions of the invention are basecl on binders wherein such
ratio is between 97: 3 and 65 :35.
The modification of at least one of the components constituting
the total binder is carried out by reaction with a compound of the general
formula
OCN - R ~ NE~ - CO - R~
n
wherein
n is l - 3;
R is an aliphatic hydrocarbon radical or an aromatic or cycloaliphatic nucleus, preferably substituted with alkyl groupsJ and
R' is a radical, reduced by one reactive hydrogen atom, of a saturatedor unsaturated alcohol, or a phenol, an alkyl substituted phenol, or
a cyclic lactam or an aldo~ime or ketoxime or an aceto acetic acid
ester or a hydroxamic acid ester.
These compounds are partially masked polyisocyanates obtained through
- 10 -
~3t;3S31
reaction o~ polyisocyanates, preeerabLy polyisocyanates c arrying iso-
cyanate groups with di~ferent reactivity, with a blockirIg agent. 2,4-toluylene
diisocyanate is preferably usecIJ one of the isocyanate groups being blocked
with monoalcohols, phenols, o~imes, lactarns, ox acetic acid esters. The
blocking agents may also carry polymerizable double bonds, for example
the blocking agent can be a mono-hydroxyacrylate. These partially masked
polyisocyanates contain an average of one free isocyanate group.
The reaction oE the partially mas~ed polyisocyanate with one of the
components of the coating composition is carried out at from 60 to 160 C.,
optionally in the presence of a solvent inert to isocyanates~ and is carried
on until the Eree isocyanate groups are substantially consumed. The highest
applicable reaction temperature is governed by the nature of the masking agent.
The progress of the reaction is reflected in the decreasing isocyanate content,
optionally also the decreasing acid value, the acid value becoming c/~nstant
in a range of from 5 to ~6 mg KOH/g at the end of the reaction. The amine
number of the reaction product is from 25 to 7Q rng KOH/g. For easier
handlingJ the components subsequent to the reaction with the partially masked
polyisocyanate, may be diluted with solvents. Suitable solvents are the low
glycol ethers, such as ethylene glycol monoethylether, ethyleneglycolmono-
isopropylether, and ethyleneglycolmonobutylether. Other suitable solvents
are alcohols such as ethanol, propanol, isopropanolJ butanol, and the like.
Another possibility is the neutralization with acids and dilution with water.
Suitable acids are mainly monobasic low molecular weight organic acids
such as formic acid, acetic acid, lactic acid, and the like.
It has been determined that at times it may be advantageous with
regard to the corrosion resistance with respect to salt solutions o the coat-
.~: , ., ' . .
36~
illgS to et-lhal-lce the harcle~ g ten(lency ot tlle coatin~ compositions through
the introd~lction of an adclitional c rosslinking component, Suitable crosslink-ing agents are urea-melcannine or phenol-formaldehyde condensates particu~
larly of the resol type. They are prepcLred according to known methods by
alkaline condensation of ornlaldehyde ancl substances splltking off formalde-
hyde to urea, nmelamine7 ben~oguanarrline, acetoguanamine, phenol, cresol,
p-tert. butyl phenol, Bisphenol ~, and the like. The methylol compounds rnay
optionally be etherified with alcohols. Particularly preferred is the use of a
phenol-formaldehyde condensate, the phenolic hydroxy groups of which are
etherified with allyl alcohol, The amount of these crosslinking agents em-
ployed may range between 3 ancl 20 percent of the tota:L binder. Since the
crosslinking agents are in most cases not directly water soluble~ they are
co-reacted with at least one of the binder components through careful conclen-
sation. The extent of this reaction is carried to an excellent water solubility
of the reaction mass upon neutralization with low molecular organic acids,
The temperatures required in general for this purpose range Erom 60 to
120 C., and the reaction time ranges from 1 to 6 hours. Additional cross-
linking agents are completely masked polyisocyanate compounds. In consti-
tution they are equal to the above-described partially masked polyisocyanate
compounds, with the exception that they do not carry a free isocyanate group.
The preparation of the binders of the present invention is carried
out either by mi~ing the components at temperatures which safeguard excel-
lent homogenization or by partial reaction between the various cornponents
at temperatures of up to 200 C. g preferably up to 100 C., safeguarding
satisfactory dilutability in water of the product. Mixing and reaction is con-
veniently effected in water-tolerant solvents such as alcohols7 glycol ethers,
ketones7 or ketone alcohols.
- 12 -
1~3~;310
The binder systerrl or the single cornponents may be processecl
together with pigments, es~tenclers, anticorrosion pigments, ancl optionally
paint additives or crosslinking catalysts to provide coacting compositions
suitable for the desirecl industrial application~ Uselul color pigments include
titanium dioxide, carbon black, iron oxides, and phthalo-cyanines. Anti-
corrosion pigments include leacl silicate, lead oxide, lead chromate, lead
silico-chromate, and strontium chromate. Normally used extenders are
aluminum silicate, talcum, barium sulfate, highly dispersed diatomaGeous
earth, ancl the like.
The basic nitrogen atoms of the binders of the present invention
are neutralized partially or totally with organic and/or inorganic acids. The
degree of neutralization depends on the individual binder system. In general
that much acid is added which gives a coating composition which in its form
of application at a pH-value of from 4 to 9, preferably 5 to 7~ is water
dilutable or dispersable. The concentration of the binder in water lies in
the range of 3 to 30 percent by weight, preferably 5 to 15 percent by weight.
On deposition the aqueous coating composition containing the
binder of the invention is wired to an electrically conductive anode and an
electrically conductive cathode, the surface of the cathode being coated with
the coating composition. A variety of chemically conductive substrates may
be coatedl in particular, metallic substrates including steel, aluminum,
copper, and the like~ but also metallized plastics or other materials covered
with a conductive coat. After deposition, the coating is optionally rinsed
with water and cured at elevated temperature. For curing, temperatures of
from 130 to 220C~, preferably 150 to 190~C., are employed. The curing
time ranges from about 5 to 30 minutes, preferably 10 to 25 minutes.
- 13 -
3~;3~
The ~olLowing c7~rnr)1es are for illustLative purposes ancl are not
to be construecl as limiting the scope of tlle invention. Parts ar e by weigSht
unless otherwise clesignated.
Preparation Of Partial Compouents A:
, , . _
~ or abbreviations and quantities, see the keg to, and Table 1.
The unsaturated oil is mixed with inhibitors 6J 7 and heated to-
gether with maleic anhydricle to 200 C. while stirring, ancl is reacted at this
temperature until no Eree maleic anhydride can be trac:ed. Upon cooling to
150 C., inhibitor 8 ancl the amine are slowly added while reiluxing. The
10 batch is reheated to 200 C., the reaction water being clistilled of. Upon
cooling to 120 C., the batch is diluted with AEGLAC (a) and the remaining
anhydride structures are opened at 90 to 100 C. with the compounds listecl
as 11. After further dilution with A:EGLAC (b~ catalyst 12 is added, and, at
60 to 120 C., the urethane compound (U1 - U4) is added. The reaction is
15 carried on until the listed acid value is reached.
For partial components A6 and A7, an adduct compouncl only is
prepared, the anhydride groups of which are opened with water or by esteri-
fication with alcohols.
- 14
l3~;3(1J
_T 1~ :B :[, E
Cornposition Ancl Speci~ication Of Partial Components A
A 1 A 2 ~ 3 , ~ 7
Linseed oil 400 - - 200 - - 500
S Polybutadiene (1 ) - 5 oo - - _ _ ~
Polybutacliene ~2) - - 380
Polybutadiene (3) - - - - 400
Polybutadiene (4) - - - - _ 400
Polypentadiene (5) - - - 200
Inhibitor (6) 0.1 0,1 0.1 0.1 0.1
Inhibitor (7) - - - - - 4 5
~ Maleic anhydride 100 100 100 100 100 100 100
Inhibitor (8)0. 2 0. 25 0,19 0. 2 0. 2
N, N-Diethylamino-
propylamine 65 - 78 65 26
N, N-Dimethylamino
propylamine - 68
DIAC (9) - - - ~ - 50
AEGLAC (a) (10)62 166 140 62 134 - . _
H2O distilled (11) - - - _ 14 _ 20
Methanol (11)15 10 - 15 - 30
n-Butanol (11) - - 30
AEGI,AC (b) (10)318 183 - 318 224
Isopropanol - - - - - 170 150
Catalyst (12)0.74 0.7 0.65 0.74 0.7
Ul (13)195 - - 195
U2 . ~13) - 253
- 15 -
3~3~
rl1 ~ B~ 1 (cont'd)
~l ~2 ~3 ~4 A5 A6 ~7
.. ~
U3 (13) _ _ 110 - ~ ~ ~
U'L ~1 3) - - - 25 3
Solvent Eor adjustment
of solids content (14) - AEGL ~EGL - - - -
Amine value mg KOH/g 45 50 53 a~s 16
Acid value mg KOH/g 19.4 15 18 19.4 90 90 150
Solids content
Percent by weight 60 60 55 60 60 70 80
Key to Table 1
(1) liquid butadiene homopolymer, viscosity: 900 mPa.s
(~L5C.); microstructure: 90% 1,2-vinyl-double bonds;
(2) liquid butadiene homopolymer9 average mblecular weight ca.
1500, viscosity: 700 mPa. s (25 C. ); microstructure: 20%
1, 2-vinyl-, 40% lJ4-trans-~ 40% 1,4-cis-double bonds;
(3) liquid butadiene homopolymer, viscosity: 800 mPa. s (20 C. )9
iodine number: 50; microstructure: 70% 1~4-cis-, 28% 1"4-
trans-double bonds~
(4) liquid butadine homopolymer, average molecular weight ca.
1400, microstructure: 75% 1, 4-cis-, 25% 19 4-trans-double
bonds;
(5 ) liquid poly- 1, 3 -pentadiene, average molecular weight ca.
1000; ~iscosity: 30, 000 mPa. s (30~ C. )
(6) N" N'-diphenyl-p-phenylenediamine
(7) Cu-naphthenate (9% metal content)
(8) 29 6-di-tert. butyl-4-methylphenol
(9) diacetonealcohol
(10) ethyleneglycolmonoethyletheracetate
(11) reactants for opening the anhydride structures
- 16 -
1113G30
-
(12) stanrlous dibutyLdilaurate
(13) urethane compouncl
Ul: 17~ g tolylenediisocyanate are reacted at 60 C. with
60 g isopropanol in 156 g AECI.AC until an NCO~value
of 18 is reached.
U2: In the presence of 0. 3 g of catalyst (12) and 203 g of
water-free AEGLAC, 174 g of tolylenediisocyanate are
reactecl at 120 C. with 130 g of ethylacetoacetate until
an NCO-value of 16 is reached.
U3 : 174 g of tolylenecliisocyanate are reactecl with 113 g ~.
-caprolactame at 60 C. ~ in l91 g of AEGLAC, until
an NCO-value oE 15 is reached.
U4: 174 g oL tolylenediisocyanate are reacted with 130 g
of 2-eth~lhexanol in 203 g of A:EGLAC at 60 C., until
an NCO-value of 14 is reached.
(14) AEGL: ethyleneglycol monoethylether
Determination Of The NCO-Value:
About 2 g of the sample are accurately weighed into a dry Erlen-
meyer flask and dissolved in toluol with gentle heating. Exactly 10 ml of
20 reaction solution (prepared through dissolution of 0. 5 moles of diisobutylamine
in 940 ml of toluol) is added with a pipette. After 3 minutes of reaction time
- at room temperature a few drops of bromophenolblue indicator (methanol
solution) are added and the sample is titrated with 0. 5 n alcoholic EI Cl
until the color turns yellow. A blank test is made the same way.
B = consumption 0. 5 n E~ Cl for blank test
V = consumption 0. 5 n H Cl of sample
A = theoretical consumption of 0. 5 n H Cl for neutralization
of the basicity of the resin
E = weigh-out in g
NCO - value = B - V ~ A
.
E
- 17 -
. .- ~ , . :
3~;3~
Partial Com~ollcrlt r~l:
950 g oE a commercially available bisphenolglycidyl ether with an
epo~y equivalent weight o~ 950 - 1000 are heated with 192 g ethylglycol ace-
tate to 100C., while stirring ancl hel(i, until ahornogeneous solution is
formed. Then 98 g taLl oil fatty acids and 1 g Or triethyl amine are added and
the batch is heated to 130 C., until the acid value is below 1 mg KOH/g. ~t
100 C., 44 g of diethylamine are slowly added while refluxing. The batch is
reheated to 130 C. and stirred for another hour at this temperature. The
viscosity of a solution oE 55 g of reaction mass and 45 g of ethylglycol is N,
Gardner. The batch is diluted with 45 g of ethyl glycol. At 80a C. 186 g of a
bisphenol-resin, 65%, is added which is prepared through alkaline condensa-
-- tion of 1 mole bisphenol and 4 moles of formaldehyde. Ater 5 hours oE reac-
tion time at 80 C. J the batch is cliluted with ethyl glycol to a total solids
content of 70 percent. The amine value of the non-volatile portion is 28 mg
KOH/g, the viscosity of a solution oE 10 parts by weight of reaction product
and 5 parts by weight of ethyl glycol is K, Gardner.
Partial Component B2:
475 g of an available bisphenol glycidylether with an epoxy equiva-
lent weight of 450 - 500 are dissolved homogeneously in 96 g of ethylglycol
acetate at 100 C., while stirring. Then 22 g of acrylic acidJ 0.022 g of
hydroquinone and 1 g oE triethylamine are added and reacted at 130 C., until
an acid value of 1 mg KOH/g is reached. At 100 C. 52 g of diethanol amine
are added and the batch is held at 130C. for 1 hour. The batch is diluted
with ethylglycolacetate to a solids content of 78 percent and is reacted at 80 C.
for 5 hours with 61 g Or methylolphenolallyl ether (viscosity 30 Poise at
25C,). The batch is further diluted to 60 percent solids with ethyl glycol
- 18 ;-
~1.13~i3~11
acetatc arlc~ aL ~;0~C. 2L7 g Or tl,( ureth.ln~ corrlpound dcscribed be]ow are
added~ together with 0. 7'L g of stanllous dibutylclilaurate. The reaction is
carried out at $0 C. until an NCO-value of zero is attainecl. The reaction
product llas a solicls content of 60 percent and the arnine value is 3~?i mg
KOH/g (DIN 53 176) Eor the non-voLatile portion. The urethane compound used
in this reaction was prepared lrom 174 g of tolylene diisocyallate (isomer
blend) and 87 g methylethylketo~ime and 174 g of ethylglycolacetate, the
oxime being aclded at 30'' C. and the reaction being finali%ed at 60 C., until
an NCO-value c~f 17 is attained.
Partial Component Bi~
103 g of diethylene triamine ancl 220 g of methylisobutylketone are
heated to boiling temperature in a reaction flask equipped with reflux conclen-
sor and water separator, until about 36 ml of water have separated. After
distillation of the surplus ketone~ about 270 g of the diketimine of diethylene
triamine are obtained.
In another reaction vessel equipped with stirrer and thermometer,
475 g of bisphenolglycidyl ether having an epo~y equivalent weight of 450 -
500 are dissolved homogeneously at 100 C. in 126 g of ethylglycol acetate.
Then 140 g of dehydrated castor oil fatty acid and 1 g triethyl amine are
added and reacted at 120 C., until the acid value has fallen below 1 mg
~OH/g. At 90C~, 123 g of the above-noted ketimine are added and the batch
is heated to 130C. A sample of the reaction mass~ with alittle butylglycol
and acetic acid, is clearly soluble in water. The viscosity of a solution OI
a, g of reaction mass and 6 g ethylglycol is L, Gardner. The batch is cooled
to 90 C. and 32 g water and 100 g of ethylglycol are added. A resin solution
with 70 percent solids content is obtained. The amine value of the non-
- 19-
~13~3
vol~ltil~ f)ox L~ i.c, clt~"~ n ~ r~o~
Partial Cornpon~nt B~:
500 g of linseecl oil is reacted with 100 g maleic anhyclride at
200" C. in the p r escnce oF 5 g o~ a copper napllthenate solution with 9 per cent
Cu, until tlle content of free maleic anhyc~ric3e ~lag fallen l~elow 1 percent.
The viscosity of a solution of 80 g of adduct and 40 g of ethylene glycol mono-
ethyl ether acetate is about 50 seconcls (DIN 53 211) and the acid value is
170 mg KOH/g. At 150C., 130 g of diethylaminopropylamine are added
within one hour and the batch is held at 180C., until the total quantity of
10 amine has reacted. After cooling to 120 C., the solids content is ad justed
to 80 percent with 175 g of ethylene glycolmonoethyl ether. (Amine number:
80 mg KOH/g)
Examples 1 - 7:
The partial components are blended as listed in Table 20 The
15-quantities refer to resin solids.
T A B L E 2
R ati o
Partial Components Amine ValueAcid Value
Example 1 50 Al 50 Bl 79 21
Example 2 60 A2 40 B3 89 11
Example 3 40 A3 60 B2 85 15
Example 4 30 A4 70 B3 92 8
Example 5 20 A5 80 B4 79 21
Comparison
Example 6 20 A6 80 B4 78 22
Example 7 10 A 7 90 B2 70 30
- 20 -
~3~:i30
E~;a m ple 8:
~t reflux tempe.rcl.ture, 238 g of clim~thylaminomethylrnethacrylate,
24 g of acrylic acid, ~L10 g oE 2-ethyl-llexylac:rylate, 340 g of styrene are
copolymerize-l in 1000 g of ethylglycol acetate in the presence of 20 g of
doclecylmerkaptan and 20 g Or azodiisobutyronitrile, ùntil the solids content
has reached 48. 4 percent. The amine value of the copolymer, on resin
solids, is about 8~ mg ~OH/gJ the a.cid value about 18 mg KO:EI/g.
At 80 C., 124 g of the urethane compound descrlbed below are
added and the charge held at 80 C. I;mtil the NCO-value has a.tta.ined æero andthe resin solution has become wa.ter dilutable upon neutralization with acids.
The solids content of the resin solution is 51 percent, the amine value of the
resir~ solids is about 75 mg KOH/g, the acid va.lue about 8 mg KOH/g ~base -
acid ratio 90: 10 mg KOH/g).
The urethane compound used in this reaction was prepared from
222 g isophorone diisocyanate and 130 g beta-hydroxyethylmethacrylate, in
the presence of 1. 3 g of hydroquinone, by reaction at 80 C. until the NCO-
value was 12.
Evaluation Of The Binders
Each 100 g of the listed binders based on resin solids were mixed
with the required quantity of acid and, while stirring, made up to 1000 g
with deionized water. From a. 10 percent solution, steel panels wired at
the cathode of an electrodeposition system were coated electrophoretically.
. The deposition time was 60 seconds in all cases. The coated substrates
were rinsed with deionized water and cured at elevated temperature. The
average film thick~ess of the cured films was from 13 to 17l1m . Table 2
gives the compiled results.
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l~ey to l'c-hle 3
~ _ . . ,
1) Quantity Or acid in g :fo:r 10() g resi.rl solids
2) E is acetic acid (80%, aqueous)
1~ is lactic acid (80%, aqueous)
A is formic acid (80%~ nqueous)
3) measured on a lO~o a.queous solution
~) Konig pendulum hardness, l~I:N 53 157 (seconds)
5) Erichsen indentation DIN 53 156 (mm)
6) hours of water soak at 40 ~'. until blistering and co:rrosion
become visible
7) ASTM-B-117-64 salt spray: 2 mrn of corrosion at the cross
incision after the recorded hours
l:~or this test degreased non-pretreated steel panels were
coated with a pigmented paint containing 100 parts by weight of
resin solids, 20 parts by weight of aluminum silicate pigment,
and 2 parts by weight of carbon bla.ck.
8) Determination of Throwing Power:
A plastic cylinder of 400 mm height and 60 mm diameter
is filled with 1 liter of paint. At a distance of about 1 mm from
the bottom of the cylinder a steel disc having a diameter of 53 mm
is mounted as an anode. The cathode is a squa.re hollow bar with
dimensions as follows: . 300 mm length a.nd lO mm of clear width,
having fixed inside in diagonal posltion a steel strip of 300 x 14 x
3 mm. The cathode is imme.rsed into the paint to a length of
270 mrn. Painttemperature is 25Co During deposition it should
not rise by more than 1 or 2 C~ Deposition is carried out with
constant voltage during 3 minutes. The deposition voltage is chosen
in order that substa.ntially no over-deposition is efi:ected at the
- 23 -
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- -
63~
outsicle oI` t~lC cath(-cl~ scluare. l~fter (iepositiorl the steel strip
is removecI ~rom the cathode and rinsed with tap water. The film
is curecl in an air circulation oven for 30 minutes at 180 C. The
visible length of deposition on the strip i,s recorcled.
Various modifications can l)e made in the aEoresaid examples and
still fall within the scope of the present invention. tt is only e~ssential that
at least one resin component oE the binder system be reactecl with the select
monoisocyanate through a reactive group on the resin component in an arnount
sufficient to improve the throwing power ~md/or corrosion resistance of a
10 coating composition containing the bincler. The actual amount basetl on the
illustrative examples will be selected depending upon the rnaterials employecl
and the end application of the coating system.
, . ' , ' :' - -, ' ~ ' ~ ` . . :
