Note: Descriptions are shown in the official language in which they were submitted.
`
LCB(805)BAK 104867Z
- D-731
NOVEL PROCESS AND COMPOSITIONS
- ,
This invention relates to novel compositions
U6efUl for the preparation of cathodic electrodeposIted
coatings, to the preparation of such CQmpO8it;0TlS 9 a~d to
methods of prepar~ng novel article~ at least a portion of
; 5 which contain a cathodically e~ectrodeposited surface coating.
It is known that variGus organic coating materials ,,
may be d~ersed in an aqueous medium and electrodeposited
upon a conductive object placed'in sai'd aqueous mediumO In
industrial electrocoat;ng practice9 a resln with or without
' 10 a crosslinking additive is deposited onto an anode. The
coated article i8 then removed from the bath and a crosslinking
reaction is effected by high temperature curingO Crosslinking
may occur ei~her by oxidative polymeriza~ion of unsaturated
,~ groups in the case of the single resin ~ystem or by reaction
,'15 of the added crosslinker with the free carboxylic acid
; .
'`', grOUp8 of the electrocoatlng re~in. Ano~ic deposition is
'i thus favored because the acidity,developed at the anode
catalyzes this crosslinking reaction.
However, snodic deposition of organic coatings
has the disadvantage of liberating metal ions formed by
', the oxidation of the substrate which con~aminates the
,,~ coating by being trapped in the depositing resin. It has
, now been found that cRthodic deposition may be used to
;. ~
eliminate thi~ contamination. Previously known technology
,3" 25 does not permit curing of these cathodic polymers sincc
,;` there i8 no acid pFe3ent to catalyze the crosslinking reaction.
"'~ ' 1
' -
, ~ . .. ..
~8~7Z
It is an object of this invention to provide novel
~ resin~compositions useful for the preparation of cathodic
; electrocoated articles. Another object of the invention is to
provide a novel cathodic resin which when dispersed in an
aqueous medium and subjected to an electric potential will
deposit upon a suitable cathode immersed in said aqueous medium
to form a coherent film. Still another object of the invention
is to provide a novel process for preparing cathodically
deposited electrocoating films. Other objects of the invention
will be apparent to those skilled in the art upon inspection of
the following description of the invention.
In accordance with one aspect, this invention provides
a process for preparing an electrocoated article which comprises
maintaining an aqueous liquid bath composition having dispersed
therein (a) particles of an amine-containing organic coating
material having a positive charge in which the amine-containing
organic material is prepared by polymerizing an amine-containing
unsaturated compound capable of vinyl polymerization, an -
unsaturated hydroxy compound or an unsaturated amide compound
; ; 20 capable of vinyl polymerization, and at least one non-ionic
ethylenically unsaturated compound copolymerizable therewith ;
and essentially free of sites reactive with isocyanates, in
.. . .
comb~nation with (b) a blocked multifunctional isocyanate chosen
such that the isocyanate will react with the said amine-containing
material only at elevated temperatures, maintaining a first
electrode in intimate electrical contact with a bath anode;
immersing in said bath as a second electrode a conductive
article at least a portion of which bears a negative charge as
cat~ode; passing an electric current through said electrodes
and said bath~thereby electrocoating said conductive article;
-2-
~ ~ .
~, ~
.~' , , , . ~
,. . . . .
!l .
8~7Z
and heating said electrocoated article after removal from said..
~ baith to form a water-resistant crosslinked polymerized electro-
coated surface on said conductive article.
The invention further provides a composition for
preparing electrocoated articles which comprises an aqueous liquid
; bath having dispersed therein a blend of (a) particles of an .
amine-containing organic coating material having a positive charge
in which the amine-containing organic material is prepared by
polymerizing an amine-containing unsaturated compound capable of
.10 vinyl polymerization, an unsaturated hydroxy compound or an
unsaturated amide compound capable of vinyl polymerization, and
at least one non-ionic ethylenically unsaturated compound copoly-
merlzable therewith and essentially free of sites reactive with
isocyanates, and (b) a blocked multifunctional isocyanate chosen
such that the isocyanate will react with the said amine-containing
material only at elevated temperatures.
In a further aspect this invention resides in a process
for preparing an electrocoated article which comprises maintaining
an aqueous liquid bath composition having dispersed therein a
blend of (a) particles of an amin~e-containing organic coating
material having a positive charge, consisting essentially of an
amine-terminated condensation polymer selected from the groups
.. consisting of amine-terminated polyamides, polyesters, polyester-
amides, polyureas and polyurethanes, and
(b) a blocked multifunctional isocyanate chosen such ~`
that the isocyanate will react with the said amin~-containing
material only at elevated temperatures;
maintaining a first electrode in intimate electrical contact with
:~ a bath anode; immersing in said bath as a second electrode a
-30 conductive article at least a portion of which bears a negative
" l
~ -2a-
.
~ ' ' ', ~
: .
- .
. :
1~8S~72
charqe as cathode; passing an electric current through said
electrodes and said bath thereby electrocoating said conductive
article; and heating said electrocoated article after removal
from said bath to form a water-resistant crosslinked polymerized
el.ectrocoated surface on said conductive article.
.This invention further provides a composition for
preparing electrocoated articles which comprises an aqueous
liquid bath having dispersed therein a blend of (a) particles
of an amine-containing organic coating .material having a positive
charge, consisting essentially of an amine-terminated condensation
polymer selected from the group consisting of amine-terminated
polyamides, polyesters, polyesteramides, polyureas and poly-
urethanes, and (b) a blocked multifunctional isocyanate chosen
such that the isocyanate will react with the said amine-containing
material only at elevated temperatures. . :~
. ~
i, `
-
: '.
~ ' ' ': :-
~ ' . .~:
'' - ' ~ :'.
.:
' ' '
. , j~
_~ -2b-
''-' ' ' ' ' .
: . .. .. _
': - ~ ' . ' ' ' .
- :.,. -
. :. : . : . - '- .
. .
``- ! i048~72
~ .
~ m e noveL aminecontaining Grganic coa ing resin
compositions of thi6 invention may be p~epared by vinyl
polymerization of unsaturated monomers containing 5 - 50
parts of an amine compound. The compositions may also be
- prepared by condensation of di- or tri basic organic acids
S with diamines or hydroxysminesO
Anoth~r met~od of preparing amine~eontaining
electrocoating formulstions i~ by the use of fatty ammonium
8alt6 or quaternary fatty amines as emulsifiers for resins
or polymers which carry no ionic chargeO By the use of the
amine soaps, a positive charge i6 imparted to the emulsified
particle which will then migrate to and depo~it upon any
eonductive object which is then cathode in the electrodeposition -
bath.
If the amine in such resins is primary or
secondary, it will serve at least ~wo important functions:
~1) it imparts a cationie charge to the polymer when
neutralized by an aeid, and (2? by virtue of its active
hydrogen, it also becomes a site for accepting crosslinks
; when the coating containing the blocked multifunctional
isocyanates of the invention is cured. If the amine i8
tertiary or quaternary, it injects only a cationie charge
without proYiding a site fo~ ero6slinking. Consequently,
hydrogen-active monomers are employed together with tertiary
. ..
and quaternary amine~
! 25 Typical ami~c compounds used for vinyl
1 eopolymerization are the following: ~
! (a) Amine-containing est~rs of monofunctional ~ -
unsat~rated acids of the formula:
1 .3
-
)4867Z
' .
: R R~
/ -R3-O-CO-C = C~z
R
` ' ' ' .
~herein Rl i9 an alkyl~ alicyclic9 or aryl group (preferably
of up to about a-_ 12 carbon atoms~o9 Rl i~ hydrogen or an
alkyl, alicyclic, or aryl group (preferably o~ up to about
8 - 12 carbon atoms); R3 i8 -(CH~)n - with n having the valuc
of 1 to 6; and R~ i8 an aLkyl group (preferably of up to
~bout 1 - 8 carbon stoms), or hydrogen. Exampleæ of such
materi818 include acrylic or methacrylic estcrs o~ t~butylamino ::
" ~ .
. ethanol and dimethylamino ethanol; ~ :
. - .
(b) Amine containing diesters of difunctional ~-
.
unsaturated aoid~ such as maleic acid, ~umaric acid, or
itaconic acid esterified with alcohols of the gencral ::
fo~ula: . :
,', . . . ' ~:
. R~ ',:
\ N-R3-OH
L5 whcrein Rl, Rz, and R3 havc thc samc mcaning as prcviously
described;
~c) Qua ernized ~ine~containing unsaturated
~eter~ of types ~a) and (b) (above) wherein R~ i~ an alkyl,
.,
- ar~l, or an alicyclic radical ~preferably of up to about
8 - 12 csrbon ato~s); snd
~d) Vinyl-containing hetcrocyclic compounds such
as N_~inyl pipcridint or ~-vinyl pyrrolidone, including
. their quatcrnized analogucs or an N-vinyl pyridiniu~ halide
(~u~h as the chloride, bronide, fluoride or iodide). -:
'-~
... . .
.. - . . : ., ~
- . . . . :
lQ48~7Z
Typically, one or sevcrsl of such amine-containing
un~aturatcd co~pounds are blcnded with ~o~ers whioh ca
no electric charge and contain no actlve hydrogen 60 that
the~ can be termed to be non-~unctional aftcr polymerization.
Typical non-func~ional ~onc~crs o th~ type are umsaturated
hydrocarbons su¢h as isop.~ene, bu~&d~ene~ ethylene9 ~t~ene,
and ~inyl acetate9 and/or ~a~yl acetat~9 and~or Yi~yl-aLkyL .
esters of dIacids; and/or unsat~rated halogen compounds
~uch as vinyl ohloride and vinyl~ene &hloride. When it i8
desirable to in~rease thc numbcr of crossl_nk-ac¢cpting
: . sites to be introduced ~n addition to the sites in the
: ~mine compounds9 unsaturated, aoti~e hydrogen-containing
compounds may be addedO Examples ~or thc~e are un~aturated
omides, such as acry~amide, ~ethacrylamidc, o~ the~.r N~aLkyl
;5 derivative~; on~;or Lr:~a ~ ated alcohols ~uch as monoesters
of diols with umsaturat2d a¢ids (hydroxypropyl- or hydroxyethyl-.
scrylatç or me~hao~ylate)0 In thc presencc of a catalyst, a
solve~t, and optional chain transfer agcnt~, addition~
polymerization of thc mixturc of unsat~ratcd compounds is
e~ected. This reaction yield~ an smine-contsining polymer --
wbich i8 one of the compo~ent~ of the new el~trocoating
. compo~itions of the invention hercin.
; PO1YCO~de~8BtiOn 1B another ~ypc of rcactio~ which :~
:. prodUcc8 sn amine containing poly~cr ~or ~se as one of the
components in the new elec~rocoat~ng compo8ition8 of thc
cntion. A polyester (or poly~mide or pol~urea or poly-
~rethanc) which i8 terminatcd at the chain cnds with ~minc
g~OUpB ma~ be prcparcd by a po~ycondensation rcaction. In
the ~ethot of preparing ~uch condenoation pr~ducts; n moles
o~ a difunctional carboxylie acld (such as phthalic, oxalic,
~ ~dipic, or sebacic scids etc.) ~8y b~ conden~ed with at
.'~ , . .
`
.
1C1 48S7Z
least n~l moles of a difunctional active hydrogen compound
such that the latter should contain at least one mole of
~mine. Typical acti~e hydrogen compounds include diamines,
alkanol amines, and blends o dihydroxyI compounds with
diamines or alka~ol aminesO The gencral formula of such
conden~ates may ~e repre~cntcd as follow~
X Y -NoCO[ Q~CO_Z-CO~n X 'f
wherein X and ~ represcnt a hydrogcn atom or a C10 C~ aLkyl;
Q i8 a (CH~)m group wh~rein m is an integcr 1 ~ 90 The
radical Z i8: -:
-(NRS) - R~ - NR~
or
- O - R~ - O -
or
_ O - Ro - NRI -
where R~ i~ hydrogen or a Gl_ C~ aLkyl and R~ i8 (CH2)8
wherein 8 i8 2 - 9 or a phenyl grGUp.
Such condensation product~ can also be obtained
b~ u~ing tricarboxylic acids and multifunctional active ~ -
hydrogen compounds with all or part of the activc hydrogen
bcing on an amine group. All or part of thc chain cnd~
~ay be wmine fu~ctional. Thc condcnsation of thc
component~ m~y be obtained by heating thc multifunctional
~cida or thcir methyl or ethrl csters with thc multifunctional
active hydrogen compoumd or by rcacting multifunctional -
acid chloridcs or chlorofor~ates of diols in organic
solvents with aqucous solution~ of the ~ultifunctionaL
~ctive h~drogen compounds. Other aminc terminated
polycondcnsa~ion products may be similarly pr~pared.
'
- - 6 _
.
10~8f~7Z
- - The blocked multifunctional i60cyanate is
prep~red by eombining a multifunctional isocyanate and
at least a stoichiometric ~mount of a monofunctional active
~ hydrogen compound. The resul~ing blocked multifunctional
isocyanate has such propcrties that, when heatcd in the
presencc of polymcric material~ contalnlng acti~ hydrogen ~-~
sites, the multif~nctional iso~yanate rcact~ with the
polymer while the monofunctional activ~ hydrogen compound
: used in blocking the isoc~anate is regeneratcdO Agents
suitablc for blocking the isocyanate arc compounds
sontaining a single amine, amide~ lactam, thiol or hydroxy
group. Hydroxyl compounds arc the preferred blocking agents
~nd are used according to the following reaction:
R~ ~-N=C=O]k ~ k R~,OH
H O
. 1 11 .
,. Ra l-N-C-OR9]k "
wherein k i8 an integer having a ~alue of at least 2
~typicAlly 2 - 8 and preferably 2 - 4), R~ i8 an organic
rsdical which does not rcact with isocyanate and R9
represcnts a monovalcnt organic residue being cither C~ - C~
alk~l, hcterocyclic, al~cyclic or an aromatic moiety in
the form of a substituted or unsubstituted monovalent group
contsining a benzcne nucleus. The term "mult~functional"
~ 8 u~ed herein means possessing morc than one isocyanatc
25 group on thc samc molecule.
. ~ .
., .
.
.
10~8~7Z
.
.:
- . m e most preferred blocking agent for the
preparation of the blocked multifunctional isocyanate . ~.
is phenol, Excellent results may also be obtained -:
- using caprolactam, methanol, and naphthol,
Typical multifunctional isocyanates which may
be used ;nclude aliphatic isocyanates such as hexylene
diisocyanates~ the trimer of hexylene diisocyanate,
octylene diisocyana~es~ decylene hexaisocyanates,
: cjclohexyl triisocyanates, vinyl polymers containing
~D i~ocyanates~ and eth~L acrylate or methacrylate, etcO - ~ :
Preferred aliphatic diisocyanates incl~d~ compounds
of the formula: - :
0=C=N r .CH2~r N=C=0 - .
: wherein r is an integer 4 - 10, typically 6 - 8. Typical
.5 aromatic isocyanate~ which may be u~ed are tolylene diisocyanate,
', tolylene triisocyanate, diphenyl tetraisocyanate, and naphthyl ::
., - .
tetraisocyanate. Other isocyanate compound~ which may be
used are reaction products of one molc of a diol with two
moles of a diisocyanate or reaction product~ of onc mole
o of a triol with threc moles of a diisocyanateO .
Typical fatty amine compound6 uscd as emuLsificr~
Rrc illustrated by t~e ge~eral form~La:
. . -- . . .
.. j R *
- N - R ***
'5 ~ **
~hcrei~ each of R~, R**, and R***~s independently ~clected from ~ -
thc gro~p consisting of 8 ~ydrogen stom, methyl gro~p~ ~
. . . . .
-
- 8 -
. :
1048672
3 p 2P ,~ 2O)qH, and ~CtH2 )NH2 wherein p and t are
integers l - 18, and q is an integer 2 - 50. Examples of
- suitable fatty amine compounds which may be used in the
invention include: diethanolamine, ethyl diethanolamine,
triisopranolamine, ethylenediamine, stearylamine,
N-ethylcyclohexylamine, 2-ethylhexylamine, soybean amine
adduct with 10-15 moles of ethylene oxide~ stearylamine
adduct with 40 moles of ethylene oxide, etc.
To each of the amine-containing organic polymers
a blocked multifunctional isocyanate compound is added so
that the weight ratio of reactive groups of the amine
containing polymer to the blocked isocyanate groups is
about 2/1 to l/5. The resulting blend is then dispersed
~ into water~ usually with cooling~ to form the aqueous
q cathodic electrocoating composition of the invention.
Typical preferred cathodic resin compositions
which may be prepared and used according to the present
invention may include the following (wherein all parts
are by weight unless otherwise indicated):
TABLE I
AMOUNT (Parts by Weight)
INGREDIENT MINIMUM MAXIMUM PREFERRED
1. Cationic Polymer: Reaction 20 95 60-80
product of 75 to 95 parts of
` monomers having no ionic charge
and containing no active hydrogen
s~chfJas~ethql~f`ffl~thy'l;Y~uty~ or
octyl acrylates or methacrylates
with 25 to 5 parts of an unsaturated
! secondary amine~ such as t-butyl
aminoethyl methacrylate.
2. Blocked Isocyanate: Reaction 5 70 20-40
product of one mole of diisocyanate
with molecular weight of 150-300
i and two moles of phenol (or triiso-
cyanate (MW 300~_ 450) with three
moles of phenol)
3. Organic Solvent: A ketone or ester 10 200 20-50
~ ether or aromatic hydrocarbon
:
-9
: ,
`` 1~48~;7Z
--` ! According to the invention, the amine-containing
positively charged polymeric organic coating materialq are
obtained by blending the blocked multifunctional isocyanate
compounds with the amine-containing polymer generally in
weight ratios of from about 501 to 1-3. The resulting
composition may be partially neutralized with an organic
acid (such as acetic acid) by the addition of an amount of
acid sufficient to react with about 10 - 100 percent of
the theoretical amine value of the amine-containing
polymer. The mixture is stirred and a small amount of
water may be added to the blend of amlne-containing
polymer and the blocked multifunctional isocyanate compound
to enhance or mod;fy the composition and include other
materials such as pigments 9 fillers 9 additional solvent-
soluble or water-dispersible resins (such as epoxy resins,
e.g, polymeric reaction products of epichlorohydrin and
bis-phenol-A), powdered metals, etcO When water is added
to the oleoresinous phase (termed the oil phase) the mixture
i8 at first a water-in-oil emulsion wherein the oil is the
.,j, : . .
~ontinuous phase, At the so-called invers;on point, the
phases reveræe, with the water becoming the continuous
phase and the oil the dispersed phaseO The resulting ~-
composition may then be further diluted with water to form
a composition containing about 5 - 25% (preferably about
8 - 15~) by weight of solids dispersed in the aqueous
medium to provide a cathodic electrocoating composition
Another method of preparing the oil-water emulsion
i~ by the 810w addition of the oil phase to highly agitated
(i.e. high shear-~tirring) water which may contain the
io required amount of neutralizing acid, The particle size
of the ao-formed emulsion may be reduced further as desired
by homogenizing the emulqion using a suitable colloid mill.
.
-- 10 _
: ,
.
j. `` 1048~7~
SReci~ic illu-~tr~tiy~ examples of a~ine-containing
organ~c poly~ers prepar~d hy h~ti~ng, by ~re~ radical catalysis,
or by ionic catalysis, etc, of the ~ndicated ingredients
to form polymers us~ful in the invention may include the
following wherein it is to ~e understood that an amine
group includes -N~2 and -N-H, and all unsatisfied nitrogen
valences are bo~ded via carbon atoms to the polymer molecule.
: TABLE II
YPICAL AMINE-CONTAINrNG ORGANIC COMPOSITIONS
INGREDIENTS AMOUNT
TYPE Amine-Containing Polymer ~Percent by Weight
DESIGNATION Compositionbased on dry Weight
of Polymer)
A 1. Ethyl acrylate 35
:. 2. Methyl methacryiate 40
3. t-butyl aminoethyl
me~hacrylate 25
Total 100%
B 1. Maleic acid
dibutyl ester 35
2. Methyl methacrylate 35
3. Styrene 10
i; 20 4. t-butylaminoethyl
methacrylate 15
- Total 100%
C 1. Ethyl acrylate 30
- 2. Methyl methacrylate 40
3. Styrene 10
4. Hydroxypropyl methacrylate 10
5. DLmethyl aminoehtyl
methacrylate 10
- Total 100
:.
D 1. Dimethyl Terephthalate . 41.8
2. Trimethylol propane 18.7
3~ 3. N,N dimethyiethanol amine 12.8
4. Stannous Octoate .. 7
5. Diiso~utyl koton~ 26.0
Total 100.0
-- 11 --
.. ~
10~8~7Z
IABLE II (Continued)
A~OUNT . -
. ` INGREDIENTS (Percent by Wei~ht :
TYPE Amine-Containing Polymer based on dry Weight
DESIGNATION Comnosition of Polvmer)
., .
. E 1. Vinyl Acetate . . 21,8
2. Dibutyl Maleate 26.7
3, t-Butyl aminoethyl methacrylate 10,9
4. Butyl Peroctoate 0,3
LO . 5, Dodecyl Mercaptsn 0.3 :
6. Toluene -- ~ 16.3
7, Butanol ~ 23 7
. Total 100.0~ .
According to the invention herein the particles .-
of amine-containing orgsnic coating material may be prepared ~:
jt ~ ~Y combining 40 percent by we;ght of a vinyl polymerizable .
amine-containing unsatursted compound, O - 30 percent by
weight of a vinyl polymerizsble unsstursted hydroxy compound -~
or unsatursted amide compound, and st lesst one nonionic
unsaturated compound essentially free of sites reactive
;~cy~n~s
~ith ~*~eyen~te~. m e particle~ of amine_containing
organic coating material msy be ~repared from a combination
.~ , . . of 3 - 40 percent by weight of an amine-containing unsaturated ~ -
compound capable of vinyl polymerizstion, 0 - 30 percent by -
weight of an unsaturated hydroxy compound or unsatursted :~
-; am~de compou~nd cspable of vinyl polymerization, snd at
` non,o~`, G
least one ~e~c unsaturated compound essentially free of
~ites reactive towsrd~ isocyanates wherein the smine-contsining ~
; unsaturated compound capable of vinyL polymerizstion is selected -:~ :
, . .
,. ' .
, ~ . ,: . : . .
. .
~ ~ ~ ` `
1(~4~7Z
S from the group consisting of amine-termunated polyamides,
polyesters, polyesteramude~, polyureas, and polyurethan~s,
According to another aspect of the invention, the
; isocyanate moiety used to pr~pare the blocked multi-
functional isocyanate is selected from the group consisting
L0 of tris (N-6-cyanatohexyl) biuretv an aliphatic or alicyclic
diisocyanate containing 6 - 20 hydrocar~on or ester radicals
: (preferab~y of up to about 25 carbon atoms~, and an
, aromatic di- or triisocyanate containing 1 - 2 benzene
rings, The blocked multifunctional isocyanate may be
,l5 selected from the group consisting of:
: (a~ a condensation product of one mole of a
diol having a moLecuLar weight of 62 - 5000 and two moles
, of diisocyanate;
(b) a condensation product of a triol with a
molecular weight of 102 - 5000 and three moles of diisocyanate;
and
(c) a copolymer prepared by vinyl poLymerization
of S - 50 percent by weight of cyanatoethyl acrylate or
methacrylate and a ~locking agent selected from the group
consisting of:
~ C~) a C~_CA alipha~ic or alicyclic alcohol;
(B) phenol;
(C) caprolactam;
(D) a C2-C~ aliphatic amine~ and
3D (E) an aliphatic amide.
A particular liquid bath composition may contain
heat curable, resinous materia~ having a molecular weight
of 300 - 20,000 in a unts of up to 50 percent by weight
. . .
~ 13 -
: . .
;':
', ' -
1048~72
based upon the weight of ~he bLend of the amine-containing
rganic co~ting material and the blocked muLtifunctional
isocyanate, wherein said heat curable resinous material is ~.,
- ' selected from the group consisting of: - ~
i (A) polyepoxides; ' '
(B) polysulfides; and . -~
: (C) formaldehyde condensates of phenols, ureas9 ., .
and melamines.
The isocyanate moiety used to prepare the bLocked
multif~nctionaL isocyanate may be selected from the group
. consisting of tris (N-6-cyanatohexyL) biuret, an aliphatic ~ '
. or alicyclic diisocyanate containing 6 - 20 hydrocarbon or -
ester radicals (preferably of up to about 25 carbon atoms),
':~ and an aromatic di_ or triisocyanate containing 1 - 2 benzene
,5 rings,
Typical heat curable resinous.materials which may ' -
be used in the invention may have a molecular weight of
. 300 - 20,000 snd may be employed in amounts of up to 50 '
.' percent by weight based upon the blend,of the amine-cont'aining
'O organic coating material and the blocked mNltifunctional
' isocyanate. The liquid bath compositions of the invention
. . ." may contain organic or inorganic pigments in amounts of up
to 40 percent by weight based upon the total weight of the
'.' organic film-forming materials,
~ _ 14 ~
,i- . -' , . ..
~' , ,. :
',. ,7~ . ' ,. '
: .
1~ 7Z
The cathodic eL~c~rodeposition may be carried out
by immer~ing as cathode the object to be coated in the
aqueous bath medium containing the positively charged
; cathodic electroconting composition of the invention and
maintaining an electrode in said bath as anode. The electro-
coated article i~ then prepared by i~aintaining a liquid bath
having dispersed therein an amine containing organic coating
material having a positive charge compined with a blocked
isocyanate compound; maintaining a first electrode in
intimate electrical contact with said bath as anode;
immersing in said bath as a second electrode a conductive
article at least a portion of which bears a negative charge
as cathode; passing an electric current through said
electrodes and said bath thereby electrocoating said conductive
article; and heating said electrocoated article to form a
water-resistant cross-Lir~ed polymerized electrocoated
surface on said electrocoated article.
The following exampLes are submitted for the
purpose of illustration only and are not to be construed
0 as limiting the scope o the invention in any way.
EXAMPLE 1
AMINE_CONTAINING POLYMER COMPOSITION
REAGENTS PARTS BY WEIGHT
!5 l. Methyl methacrylate 500
2. Butyl acrylate 350
3. t-butyl aminoethyl methacrylate 150
4. Azo_bis(isobutyronitrile) lO
5. Butyl mercapto propionate 30
~0 6. Methyl ethyl ketone ~olvent 445
- 15 --
,
1~4~7Z
POLYMERIZATION PROCEDURE: ~
. . .
Ingredient 6 is placed in a 2 liter glass
reactor equipped with stirrer, thermometer, conden~er,
addition funnel, and a nitrogen gas inlet tubeO The
~olvent (under a nitrogen atmosphere~ is heated (using
a heating mantle) to 80C. at which time the mixture of all
the reagents i8 added over a period of 3-4 hours. After
~ddition is complete, the resin solution is held at 80C.
~or an addi~ional 3-6 hours, cooled and discharged.
,0 EXAMPLE 2
AMINE_CONTAINING POLYMER COMPOSITION
. . REAGENTS --- PARTS BY WEIG~lT
1. Methyl methacrylate 600
2. Butyl acrylate 2 5
. LS 3. t-butyl aminoethyl
methacryla~e 150
;` 4. Mercapto ethanol 20
; 5. Azo_bis(isobutyronitrile) 10
6. Ethylene glycol mono methyl ~-
'0 ether 690
: POLYMERIZATION PROCEDUR.E: .
.. .
; All 8iX o~ the above reagents are placed in a
2 liter glass reactor as in Example 1. The temperature
i8 brought to 75C. at which time the heat source i8
, ~
~5 removed. Exothermic heat raises the temperature to 80C.
where ~t i8 maintained by external cooling for about 1
hour, after which time the external heat source i8 reapplied
und the temperature maintained at 80C. for 2-5 hours.
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EXA~LE 3
~" AMINE -CONTAINING POL~ER C O~OS ITI ON
`~ - REAGENTS PARTS BY WEIGHT
.
1. Ethyl acrylate 300
2. - Methyl methacrylate 400
`; 3, Styrene 100
~ 4. HydroxypropyL methacrylate 100
- 5. Diethyl aminomethyl methacrylate 100
6. Butyl mercapto propionate 30
.10 7. Azo-bis(isobutyronitrile) 10
8. 2-butanone 425
. POLYMERIZATION PROCEDURE:
The same procedure as æet forth in Example 2 was
followea.
EXAMPLE 4
BLOCKED MULTIFUNCTIONAL ISOCYANATE COMPOUND
, . , . _ _
AMOUNTS AND
. REAGENTS CONCENTRATI ONS
. 1. (Phenol 468 grams
(Tetrahydrofuran (THF) 126 ml ~
~20 2. (Stannous octoate 0.28 grams
~ (THF 6.3 ml
: 3 (Tri (isocyanatohexYl)~ biuret 921.2 grams
.. . (T~IF 170. 6 . ml
94 ml
PROCEDURE:
Reagents (1~ and (2) were added to a one liter
round bottom flask equipped with stirrer, condenser,
: . .
. thermometer, addition funnel and nitroge~ ga~ inlet tube
.
. and cooled to below 35C, Reagent (3) is added rapidly;
.~; the temperature being maintained below 35C. by cooling.
The dropping funnel i8 rinsed with Reagent (4) which is
.~ also added to the reactor. The reaction is exothermic,
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~ 1~48~72
the~temperature rising to 50C. in about 40 minutes. The
.
temperature i8 heald at 50-55C~ for 1/2 to 1 hour by heating
when necessary, then increased to 70Co where it i8 held to
yield a 070 isocyanate value (approximately 2 hours).
EXAMPLE 5
REAGENTS AMOUNTS
1. (Trimethylol propane 53.6 g (0.4 mole)
(Dry 2-butanone 93.7 g (116.3 ml)
2. ~Tolylene Di_socyanate 208.8 g (1.2 moles)
3. (Phenol 113.9 g (1.2 moles)
, . -
(2-Bu~anone (dry) 72.25 g (90 ml) ~
; 4. (Stannous Octoate 0.4 g ; ~ -
(2-Butanone ~16.0 g (20 ml)
,
PROCEDURE. -
(a) Reagent (1) is charged to dry 1000 ml flask
equipped with ~tlrrer condensation thermome~er, addition
. .
~unnel, nitrogen inlet tube, and heated to 45-50C.;
(b) Reagent (2) i~ added over a period of 1-1.5
hours, the temperature being controlled at 50C.
(c) Reaction held until the percent isocyanate
; (NCO) is 15.4h (approximately two hours)5 cooled to 30C.;
(d) Reagent (3) is added, the reaction i~ heated
, ~
; to 70C. and held for four houræ; and
(e) Reagent (~) ~ 8 added and the reaction
.,;,^. .
~ continued to 0% NCO (approx~mately 25 hours).
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1048f~i72
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: EXA~5PLE 6
BLOCI~:D MI~LTIFUNCTIONAL ISOCYANATE COMPOUND
~ ' REAGENTS Al~SOUNTS
:,- 1. Caprolactam , 1700 parts
2. Methyl Ethyl Ketone 1515 parts (1436 ml)
3. Tris(isocyanatohexyl)
" biuret 2g20 parts
,' 4, Stannous Octoate 1.46 parts
5, Methanol 48 parts
, 10 PROCF.DURE: ,
' : The caprolactam and 500 ml of the ketone are
~ added to a 5000 ml round bottom flask equipped with a
,' s'irrer, nitrogen gas inlet, condenser and dropping
funnel. Heat is applied by a heating mantle and the
' 15 'temperature is raised to 60C. at which time the stannous
octoate is added as a solution in 40 ml of the ketone solvent.
,: .:
The biuret is dissolved in the remainder of the solvent
... .
;';, and the solution is added to the reaction vessel over a
,'~ half hour period. The temperature is raised to 80C. '
; 20 and held there until the percent isocyanate value is
,:.
'' below 0.1~, at which time the methyl a'icohol is added.
After one haE hour the ,blocked multifunctional isocyanate
product.
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~EXAMPLE 7 10~8~72
ELEcTRt)coATlNG COMPOSITION_
INGREDIENTS . AMOUNTS
(Parts by Weigh~
1. Amine-containing polymer solution
of Example 2 ( 60~o Non-Volatile
~aterial, NVM~ 600
2. (80~ NVM) Phenol-blocked
trisisocyanate of Example 6 338
3. Epoxy Re~in 270
4. Red Iron Oxide, dispersion grade 100
PROCEDURE:
Items (1) and (2) are homogeneously mixed at
- moderate speedsO Item (4) is blended into the mixture under
high shear ~tirringO Enough acetic acid i8 added to
neutralize the amine content to 100% of theoretical.
100 parts of water (deionized) are added at a high rate
of stirring after wh;ch the epoxy resin ingredient (3) is
dispersed in the mix~reO Deionized water is added to
produce a 10 NVM bath, which is used in electrodeposition
` according to the method of Example 9~ below
; EXAMPLE 8
i..
^; INGREDIENTS AMOUNTS
(Part~_by Wei~ht)
s 25 1. Amine_containing polymer
` (70% NVM) of Example 3 1,073
- 2. Phenol-blocked multifunctional
isocyanate compound of Example 5
x:, (807o NVM) , 313
~,~ 30 PROCEDURE:
vi - Ingredients (1) and (2) are blended under
moderate stirrin$; acetic acid (50~ of theoretical amine
value~ and water are added to form a 1570 emulsion.
Electrodeposition i~ performed a~ described in Example 9~ below
The resultant, heat-cured, fi~m i8 clean, hard, glo88y
snd water resistant.
.
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' EXAMpLE~ 1~48f~72
COATING FORMULATION
.
NGREDrENT AMOUNT
GParts by ~eight~
1. Amine-containing polymer solution
- of Example lC70% NVM~ 713
2. Phenol blocked triisocyanate
t80% NVMl of Example 5 375
3. Phenolic resin solution C60~ NVM) 333
. . .
4. Titanium dioxide pîgment 200
; Note; Item ~3~ is a polymerized
lq mixture of the allyl ethers
of mono-, di, and tri-methyol
phenols.
PROCEDURE:
r
The TiO2 and part of the phenolic resin solution
are mixed and ground on a 3-roll mill. The paste is let-
down ~diluted~ with ~he re~.ainder of the phenolic resin and
the mixture of components Cl) and t2~. Enough acetic acid
is added to neutralize the amine value of the acrylic resin
to 50% of theoretical. Deionized water is now added (under
~oderate stirring~ slowly to form an oil-in-water emulsion
at 10% total Non-Volatile Material. The bath is placed
in a stainless steel tank which becomes the anode for
electrodeposition. The article to be coated is immersed
and voltage of about 10Q - 2aa Volts Direct Current (VDC)
i8 impressed upon the system. After 1 minute the coated
,...
article is removed from the bath, rinsed and cured at 150C.
- 200C. for 15 minutes to produce an excellent coherent
l electrocoat.
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` `1048~7Z
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EXAMPLE 10
``. CLEAR ELECTR(~CQATI~G FORMI~LATION
: . :
INGREDIENT AMOUNT
(Parts by Weight~
1. Amine_containing polymer solution
of Example 3 1,214
2. Phenol-blocked triisocyanate
compound of Example 5 185 --
3. Acetic Acid 22
4. Deionized Water 12,SOO
PROCEDURE: -
" Ingredients (1) and (2) are blended on moderate
speed mixer. Ingredient (3) -i8 added and homogeneously
blended. Ingredient (4) i8 next added 810wly under high
, ~ ,
~ 15 shear stirring until inversion to oil-in-water emulsion.
,~; . .
The rest of deionized water is added to reduce emulsion to
about 10% by weight of solidsO The bath is placed into a
plastic tank which contains stainless steel plates (as
anodes) clamped to the sides. The article to be clear-
coated is immersed, electrocoated at 150 volts (DC),
rinsed free of bath, and cured at 125~. - 200C. for
30 - 15 minutesO The film is hard, clear, glossy, and -~
~. .
resistant to moisture and salt.
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` :10~8~72
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EXAMPLE 11
- ELECrROCOATIUG ~'ORMULATION
.;. - ~..... .
INGREDIENT . AMOUNT
. (Parts by Wei~ht)
1. Amine-containing polymer soLution
of Type designation E 600
! 2. Phenol-blocked diisocyanate compo~nd
:.: of Example 5 225
.;
-~ 3. Phenolic resin solution - 330
. . .
4. Titanium dioxide pigment 150
.. :
. PROCEDURE:
; The same procedure as set forth in Example 9
,. was repeated to produce an excellen~-coherent pigmented
,
;. electrocoat.
. . .-
:~ 15 EXAMPLE 12
. . EL~CTROCOATING FORMULATION
: INGREDIENT AMOUNT : -~
~`: (Parts by Weight) : ~
1. Amine-containing polymer solution ~ :
:~i 20 of ExampLe 2 (60% NVM) 600
... . .
2, Phenol-blocked multifunctional
:;~' isocyanate compound of Exam~le 6
~ (70% NVM) 257 :: :
i:. - ':
r~,; 3. 60% melamine-formaldehyde resin
:. 25 solution . 300
" 4. Red iron oxide pigment 280
: . PROCEDURE: -
,., ~ . .
(a) Grind ingredient (4) and part of ingredient (3) -~:
on three roll mill, Blend the remainder of (3) with (1) and
(2). Stir for 1/2 hour, :
~ (b) Add six parts of scetic acid, blend well,
; (c) Add deionized water slowly to form a paste
:~ under high shear stirring and to prepare an oil-in-water
': emulsion.
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1~8~7Z
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(d) Electrocoat as described in ExampLe 10
.
to form an electrocoat which is resistant to salt spray
~ nnd detergents and which is employed as an excellent primer
:~ ' for steel substrates
U S EXAMPLE 13
. ~,............... . ..
. ELE COATING FO~SU~TION
.. INGREDIE~T AMOUNT
. ~ (Parts by Weight)
1, Amine-containing polymer solution
of Example 1 600
`,. 2. Caprolactam-blocked isocyanate - .
~: compound of Example 6 170
~." . __
3, Glacial acetic acid 63(ml)
~' PRoC~nUr~
Ingredients (1~ and (2) are blended together
~: with a low shear stirrer, Ingredient (3) is added and ~:
. ~ -.
blended into the mixture. ~Sufficient distilled water is
't' added slowly to form a water-in-oil emuLsion, after which -
`, additional water is added rapidly in an amount sufficient
.20 to form a l0% by weight non-volatile material (NVM) electro- -
coating bath, Steel article~ are electrocoated as described
in example 1 to form smooth, coherent electrocoat~ with
f~ ' ~excellent adhes;on and uniform coverage in recessed areas,
,,. EX~*~LE 14
~ 25 El,ECTROCC~TING FORMUI~TION
,. . . .
~;;: INC.~EDIENT AMOUNT
(Parts by Weight)
1. Fatty amune* 50
,; .
2. Hydroxyl-containing acrglic resin
(70æ NV~) 70
3. Phenol-blocked isocyanate compound
;~ o~ Example 6 (80~ NVM) 375
- 4. Phenolic resin solution (6070 NUM) 300
~: 5. Carbon black 10
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PROCEDURE: j
The TiO~ and part of the phenolic resin solution
are mixed and ground on a 3-roll mill, The paste i9 let-
- down (diluted) with the remainder of the phenolic resin and
the mixture of components (1~ and (2), Enough acetic acid
i8 added to neutralize the amine value of the acrylic resin
.,
: to 50~0 of theoretical. Deionized water is now added (under
moderate stirring~ slowly to fonm an oil-in-water emulsion
at 10% total Non-Volatile Material, The bath is placed ~-
LO in a stainless steel tank which becomes the anade for
; electrodeposition, m e article to be coated is immersed ~ -
and a voltage of about 100 - 200~Volts Direct Current (VDC)
~. i8 impressed upon the system, After 1 minute the coated
',~ article is removed from the bath, rinsed and cured at 150C.
'L5 - 200C. for 15 minutes to produce an excellent coherent
-electrocoat.
~ *Distilled lauryl primary amine which
;l contains 1% of C10 and 9~/0 o~ Cl 2 or
i distilled tall oil fatty primary amine
; 20 which contains 1% of Cl~, 9~ of
` Cla (saturated~, 9Q~ of Cl8 (unsaturated~,
~ . . .
: Although this invention has been illustrated by
reference to specific embodiments, modifications thereof
. which are clearly within the scope of the invention will
be apparent to those skilled in the art,
;.
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