Note: Descriptions are shown in the official language in which they were submitted.
105ZOZ9
BACKGROUND OF THE INVENTIODl
1. Field o~ the Invention
This invention relates to a process for the production
o~ pigmented or nonpigmented self-cross-linking lacquers
utilizing an aqueous dispersion.
2. Prior Art
The hltherto customary coatings for metals have
been based on the use of a drying oil and of a fast drying
lacquer base substance (such as, natural resins, a comblnation
of natural and synthetic resins or of an alkyd resin modified
with a urea, melamine or phenol forma1dehYde resin) - such
contains volatile organic solvents which frequently are
flammable and WhiCh during the coating process develop harmful
vapors. Because of this, special measures are needed for
the recapture of the solvents themselves. Other proposed
blnders for coatings contaln unsaturated polymer systems,
such as, butadiene-styrene lattices. However, this polymer
type is imbued with the known disadvantages of becoming
brittle and capable of discoloration upon progressive oxidation.
There has been a need for a long time for coating
compounds which can be applied from aqueous media and conse~ -
quently do not develop any undesirable flammable or toxic
vapors, and which are self-cross-linking solely as a result
of heat action.
- Known aqueous systems are described in the U.S.
Patent nos. ~,760,886, 2,918,391 and 3,033,811. These coating
~; masses are not satis~actory since they are inclined to dry
- prematurely during application because they are not able to
form a smooth surface film due to the formation of blisters
during the heat treatment.
Heat hardenaDle coating compounds in the form of
.
_3_ ~;~
105ZOZ9
aqueous lattlces are also known (see German published application
no. 2,211,169). Such are produced in accordance with the
customary emulsion polymerization process. The binders used
in such are based on two components, one being an additional
copolymer consisting of an aromatic monovinyl monomer, an
ester of the acrylic or methacrylic acid, at least one olefinic
unsaturated monomer with an amlde or hydroxyl groups and one
olefinically unsaturated monomer with a carboxyl group, and
the other consisting of a water soluble urea-formaldehyde
resin. The disadvantage of these coating compounds lies in
the fact that they are not self-curlng ~self-cross linking)
and thus a multiple of important characteristics and properties
(such as, pigment compatabllity, distributlon of the pigments,
adhesive capacity, luster, resistance to water and solvents,
resistance to heat and atmospheric corrosion) are impaired
through the addition of a considerable amount of a second
cross-linking component.
BROAD DESCRIPTION OF THIS INVENTION
An object of thls invention is to provide a process
~or producing self-cross-linking lacquers utilizing an aqueous
dispersion. Another object of this invention is to provide
self-cross-llnking lacquers which, once self-cross-linked by
heat treatment have good resistance to heat and atmospheric
corrosion, high chemical resistance, and which result in
glossy coatings which are both hard and tough. otne~ objects
and advantages of this invention are set out herein or are
obvious to those ordinarily skilled in the art.
Such objects and advantages are achieved by this
invention.
This invention lnvolves a process for preparing
a lacquer utillzing an aqueous dispersion, the lacquer being
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~05;~029
pigmented or non-pigmented, being self-cross linking upon
heat treatment and containing a binder consisting essentlally
of the following monomers;
(aJ 30 to 70 parts by weight of at least one monomer
whose homopolymer has a theoretical glass
temperature of less than 10C., based on the
total weight of the binder,
b) ~0 to 70 parts by weight of at least one monomer
whose homopolymer has a theoretica1 glass
temperature of more than 30C., based upon the
total weight of the binder,
(c) 0.5 to 5 parts by weight of at least one
polymerizable acid and/or salt thereof, based
upon the total weight of the binder,
(d) 2 to 35 parts by welght of at least one reactive
monomer, based upon tne total weight of the
bind~r, and
(e) 0.5 to 35 parts by weight of at least one alkali
or ammonium salt of a polymerizable sulfonic
acid, based upon the total weight of the binder.
The process includes conducting the polymerization
in an aqueous dispersion in a reaction vessel at a preselected
temperature between 15 and 30C. and at a starting pH of 3
to 4 in the presence of a redox system consisting of 0.005 to
0.5 percent ~y weight Or at least one alkali and/or ammonium
persulfate, based upon the total weignt of the monomers, 0.~001
to O.S percent by weight of ascorbic acid, ~ased upon the
total weight of the monomers, and 10 to 30 p.p.m. of at least
one iron (IIJ-salt, based upon the total weight of the monomers.
No more than 30 percent of the monomers and tne majority of
the persul~ate is inserted into the reaction vessel before
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lOSZ029
polymerlzation step starts. After the polymerlzation step
starts, the remainlng amount of monomers is dosed concurrently
and parallel lnto the reaction vessel with the iron (II)-salt
and the ascor~ic acid in such a manner that the preselected
polymerization temperature remains almost constant.
DETAILED D~SCRIPTION OF THE lNV~NTION
The polymerization temperature can be between 15
and 3~C. and is preferably between 20 and 23C. Tne control
of the polymerization temperature is preferably carried out
essentially automatically by synchromlzing tne dosing in of the
iron ~IIJ-salt and of the ascorbic acld as well as of the rest
of the monomers with the outside cooling so as to màintain a
preselected constant polymerization temperature which will not
deviate more than - 1C. during tne po~ymerization. Herein,
an almost constant polymerization temperature means a deviation
no larger than about - 2C. during polymerization. Preferably
. , .
` the polymerizatlon temperature does not deviate more than
- 1 C. during polymerization. A constant polymerlzation
temperature can be o~talned by doslng ln the remaining amount
of the monomers concurrently and parallel with the iron (II)-
salt and the ascorDic acid at such a rate the preselected
polymerlzation temperature remains constant. A constant
polymerization temperature (- 1C~) can ~e obtained by control-
ling the polymerization rate by controlling the amount and
speed of dosing in the reducing initlator components.
The preferred alkali or ammonium persulfate is
potassium persulfate and other examples of the persulfate
are sodium persulfate, ammonium persulfate, llthium persulfate,
rubidium persulfate and cesium persulfate. Mixtures thereof
can be used 0.~05 to 0.5 percent hy weight, and preferably
0.05 to 0.2 percent by weight, of at least one alkali and/or
lOS;~OZ9
ammonium persu~fate, ~ased upon the total weight of the monomers,
is used. At least a majority (~0 percent) of the alkali and/
or ammonium persulfate lS inserted into the reaction vessel
before the polymerization step starts and the remainder is
added ln doses during or at the end of the polymerization
reaction.
Ascor~ic acid is used in an amount between 0.001
and 0.5 percent by welght, and prefera~ly between O.Ul and
0.2 percent by weight, based upon the total weight of the
monomers. The ascorbic acid is added to the reaction vessel
together wlth the emulsifier and with the iron (II)-salt. The
iron (lI)-salt is used in an amount between 10 and 30 p.p.m.,
and preferably between lU and 20 p.p.m., based upon the total
weight o~ the monomers. The preferred iron (II)-salt is ferrous
sulfate and other examples of the iron (II)-salt are ferrous
acetate, ferrous chloride, ferrous chromite, ferrous bromide,
ferrous fluoride, terrous citrate, ferrous carbonate, ferrous
iodide, ferrous formate, ferrous perchlorate, ferrous lactate,
ferrous nitrate, ferrous oxalate, ferrous sulfate, and ferrous
sulfide. Besiae that, other iron compounds and complexes can
also be used whlch under the glven circumstances releases iron
(IlJ-ions. Examples of such are iron (IlI)-sulfate, iron (II)-
chloride, the iron salt of ethylenedlaminetetraacetic acid
or ferrocene. Any suitable emulsifier or emulsifiers can be
used. The anionlc wetting agents are the ~est emulsifiers,
and preferably are used in a quantity-between 0.05 to 5 percent
by weight, based on the monomers. Suitable anionic emulsifiers
are the alkyl sulfates, sulfates of alkyl and alkylarylpoly-
ethoxy alkanols, alkyl sulfonates, and alkylaryl sulfonates
as well as esters of the sulfosuccinic acid with alkanols.
The starting pH is between 3 and 4, preferably is
lOSZOZ9
~.5. ~he p~ lS adjusted, i~ necessary, to such by means of
an orga~ic acid, and preferably a polymerizable acid,- such as
acrylic acid, methacryllc acid, maleic acid, fumaric acid, etc.
Any of the polymerizable (organic) aclds listed below can be
used. ~xamples of other organic acids are saturated (fattyJ
acids (having 1 to ~0 carbon atoms), such as, acetic acid,
myrlstlc acid, formic acld, pentadecanoic acid, propibnic
acid, palmitic acid, butyric acid, margaric acid, valeric acid,
stearlc acid, caproic acld, nonadecanolc acid, enanthic acid,
arachidic acid, caprylic acid, isobutyric acid, pelagonic
acid, isovaleric acid, capric acid, trimethylacetic acid,
undecanoic acid, isocaproic acid, lauric acid, dimethylethyl-
acetic acid, tridecanoic acia, and 2-ethylhexanoic acid.
~uring the polymerization the p~ value can change without
impairing the polymerization.
For special purposes, for example, in order to
; reduce the baking temperature, 1 to 15 percent by weight, based
on the aqueous polymerization dispersion, of a water solub~e
melamine and/or urea resin can be added to the dispersion after
the polymerization.
30 to 70 parts by weight, and preferably 40 to 60
parts by weight, of the monomer whose homopolymer has a
theoretical glass temperature of less than 10C., based on
the total welght of the ~inder, is used. Mlxtures of such
monomers can be used in a total amount within such ranges.
Examples of monomers whose homopolymers have a
theoretlcal glass temperature of less than 10C. are: acrylic
acid esters having 1 to 8 carbon atoms in the ester radical
(group), such as, methyl acrylate, ethyl acrylate, propyl
acrylate, heptyl acrylate, butyl acrylate, octyl acrylate,
pentyl acrylate, isobutyl acrylate, hexyl acrylate, sec.-
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1052029
butyl acrylate, ethylhexyl acrylate, tert.-butyl acrylate,
lsopropyl acrylate, ~-methyl-l-butyl acrylate, dimethylpropyl
acrylate, ~-methyl-l-butyl acrylate, ~-pentyl acrylate, 2-
methyl-2-butyl-acrylate, 3-pentyl acrylate, 3-methyl-2-butyl
acrylate, 2~ethyl-l~butyl acrylate, ~-methyl-l-pentyl acrylate,
3,3-dimethyl-1-butyl acrylate, 3-methyl-1-pentyl acrylate,
2,3-dimethyl-1-butyl acrylate, 3-methyl-2-pentyl acrylate,
2,2-dimethyl-3-butyl acrylate, 4-methyl-2-pentyl acrylate,
2,3-dimethyl-2-butyl acrylate, 2-methyl-3-pentyl acrylate,
2,4-dimethyl-3-pentyl acrylate, 3-methyl-2-pentyl acrylate,
2,4-dimethyl-1-pentyl acrylate, 3-methyl-3-pentyl acrylate,
2,3,3-trimethyl-2-butyl acrylate, 2-hexyl acrylate, 2,4,4-
trimethyl-l-pentyl acrylate, 3-hexyl acrylate and 2-octyl
acrylate; methacrylic acid esters having 6 to 18 carbon atoms
in the ester radical, such as, hexyl methacrylate, octyl
methacrylate, n-decyl methacrylate, n-tetradecyl methacrylate,
heptyl methacrylate, pentadecyl methacrylate, nonly methacrylate,
hexadecyl methacrylate, undecyl methacrylate, heptadecyl
methacrylate, dodecyl methacrylate, octadecyl metnacrylate,
trldecyl methacrylate, 2-ethyl-1-butyl methacrylate, 3-hexyl
methacrylate, 2-methyl-1-pentyl methacrylate, 2-hexyl
methacrylate, 3-methyl-1-pentyl methacrylate, 2,3,3-trlmethyl-
2-butyl methacrylate, 4-methyl-~-pentyl methacrylate, 3-
methyl-2-pentyl methacrylate, 4-methyl-1-pentyl methacrylate,
2-methyl-2-pentyl methacrylate, 2-octyl metnacrylate, 3-metnyl-
3-pentyl methacrylate, 2,3-dimethyl-1-butyl methacrylate,
3,3-dimethyl-1-butyl methacrylate, 2,3-dimethyl-2-butyl
methacrylate, 2,4-dlmethyl-3-pentyl methacrylate, 2,4-dimethyl-
l-pentyl methacrylate and 3-methyl-2-isopropyl-1-butyl
methacrylate; vinyl esters having 3 to 20 carbon atoms in the
acid radical (preferably ones with a branched carbon chainJ,
10520Z9
such as, vlnyl propionate, vinyl butyrate, vlnyl valerate,
vinyl cap ~nate, vinyl stearate, vinyl asobutyrate, vlnyl
Versatate ,* vinyl isobutyrate, vinyl 2-methylbutanoate,
vinyl lsovalerate, vinyl pivalate, vinyl 4-methylpentanoate,
vinyl isocapronate, vlnyl 2-methylpentanoate, vlnyl 2-ethyl-
butanoate, vinyl 3-methylpentanoate, vinyl 2,2-dimethylbutanoate,
vinyl heptanoate, vinyl 3,3-dlmethylbutanoate, vlnyl octanoate,
vinyl 2,3-dimethylbutanGate, vinyl nonanoate, vinyl 2-ethyl-
hexanoate, vinyl decanoate, vinyl tetradecanoate, vlnyl
pentadecanoate, vinyl dodecanoate~ vinyl palmltate, vinyl
undecanoate, vinyl margarate, vinyl trldecanoate, vlnyl non-
adecanoate and vinyl arachldate; ole~ins having 2 to 10
carbon atoms, such as, ethylene, butylene, propylene, 2,3-
dimethyl-l-butene, ~-butene, 3,3-dimethyl-1-butene, 3-methyl-2-
: butene, 2,3-dimethyl-2-butene, 3-methyl-1-butene, 2-ethyl-
3-methyl-1-butene, 2-methyl-1-butene, 2-methyl propene, 2-
ethyl-l-butene, l-pentene, 2-methyl-2-butene, 2-pentene,
tetramethyl ethylene, 3-methyl-2-pentene, unsym-methyliso-
propylethylene, ~,3,4,4-tetramethyl-1-hexane, 3,4,5,5-tetra-
methyl-2-hexene, t-butylethylene, 3,4,5,5-tetramethyl-2-hexene,
2-ethyl-1-pentene, 3,5,5-trimethyl-2-heptene, Z-methyl-1-
pentene, 2,~-dlmethyl-1-pentene, 3-methyl-1-pentene, ~,4-
dimethyl-l-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-
pentene, 3-ethyl-2-pentene, 2,3-dimethyl-2-pentene, 2-methyl-
2-pentene, 2,4-aimethyl-2-pentene, 3-methyl-2-pentene, 3,4-
dimethyl-2-pente ~ 4-methyl-2-pentene, 4,4-dimethyl-~ pentene,
* vinyl Versatate are the vinylesters of Versatatic
- acids which is the trademark of Shell for a number of multlple-
- branched saturated monocarbon atoms with Cg, C10 and C
and tert. COOH-groups.
--1~)--
~ 10520Z9
l-hexene, 2-hexene, 3-hexene, 2-methyl-1-hexane, 2,5-~imethyl-
3-hexene, ~-methyl-l-hexene, l-neptene, 4-methyl-1-hexene,
2-heptene, ~-methyl-~-hexene, 3-heptene, 2-methyl-2-hexene,
l-octene, 3-methyl-2-hexene, 4-methyl-2-hexene, 2,4,4-trlmethyl-
l-pentene, ~-methyl-2-hexane, ~,4,4-trimethyl-2-pentene, 2-
methyl-3-hexane~ 2,3,4-trlmethyl-2-pentene, 2,2-dimetnyl-3-
nexene, l-nonene, 3,~-dlmethyl-4-nexene and l-decene; diolefins
(dienes) having 3 to lU carbon atoms, such as propadiene, 1,2-
butadlene, 4-metnyl-1,3-pentadiene, 1,3-butadiene, 2,3-
pentadiene, 3-methyl-1,~-butadiene, 2,4-hexadlene, 2-methyl-
1,3-butadlene, 1,2-pentadiene, 2,3-dimethyl-1,3-butadiene,
1,3-pentadiene, 2,5-~imethyl-hexadlene, 1,4-pen~adiene, 2,6-
dlmethyl-heptadiene, 1,5-hexadiene, 2,4-neptadiene, 3,7-
: dimethyl-l,~-octadiene, 1,6-octadiene, 2,6-dimethyl-2,6-
oct~diene, 2,6-octadlene, 7-methyl-2,4-octadiene, 2,4-octadiene,
2,7-oc.tadiene, 2,4-dimethyl-3-isopropyl-1,3-pentadiene, nonadlene,
1,3~decadiene and 2,3,3,4-tetramethyl-1,4-pentadiene; maleic
acid esters having 4 to 18 carbon atoms in the ester radical,
such as, butyl maleate, isobutyl maleate, pentyl maleate,
tert.-butyl maleate, hexyl maleate, dimethylpropyl maleate,
heptyl maleate, 2-methyl-2-butyl maleate, octyl maleate,
2,3-dimethyl-1-butyl maleate, decyl maleate, 2,2-dimethyl-~-
butyl maleate, undecyl maleate, ~,3-dimethyl-2-butyl maleate,
dodecyl maleate, octadecyl maleate, nonyl maleate, tridecyl
maleate, heptadecyl maleate, tetradecyl maleate, pentadecyl
maleate, hexadecyl maleate, 2-methyl-1-pentyl maleate, 2,4
dlmethyl-3-pentyl maleate, 3-methyl-1-pentyl maleate, 2,4-
- dimethyl-l-pentyl maleate, 4-methyl-1-maleate, ~,3,3-tri-
- methyl-2-butyl maleate, 3-methyl-2-pentyl maleate, ~-ethyl-
l-hexyl maleate, 4-methyl-2-pentyl maleate, 2-octyl maleate,
2-methyl-1-pentyl maleate, 2,4,4-trimethyl-1-pentyl maleate,
--11--
10520Z9
~-methyl-~-pentyl maleate, 2,~,4-trlmethyl-1-pentyl maleate,
2-methyl-2-pentyl maleate, 2,3,4-trlmethyl-2-pentyl maleate,
2-ethyl-1-butyl maleate, 3,3,4-trimethyl-1-pentyl maleate,
and 3-methyl-2-1sopropyl-l-butyl maleate; fumaric acid esters
having 4 to 1~ carbon atoms in the ester radical, such as,
butyl fumarate, 2-methyl-1-butyl fumarate, pentyl fumarate,
3-methyl-1-butyl ~umarate, hexyl fumarate, 2-ethyl-1-hexyl
fumarate, heptyl fumarate, nonyl fumarate, undecyl fumarate,
octyl fumarate, octadecyl fumarate, heptadecyl fumarate,
decyl fumar~te, pentadecyl fumarate, hexadecyl fumarate,
dodecyl fumarate, tert.-butyl fumarate, 2-octyl fumarate,
tridecyl fumarate, diethylpropyl fumarate, tetradecyl fumarate,
3-methyl-2-isopropyl-1-butyl fumarate, isobutyl fumarate,
2-methyl-l-pentyl ~umarate, 2,3-dimethyl-1-butyl fumurate,
3-methyl-1-pentyl fumarate, 2,2-dimethyl-2-butyl fumarate,
2-ethyl-1-butyl fumarate, 2,3-dimethyl-2-butyl fumarate,
4-methyl-1-pentyl fumarate, 2,4-dimethyl-3-pentyl fumarate,
3-methyl-2-pentyl fumarate, 2,4-dimethyl-1-pentyl fumarate,
4-methyl-2-pentyl fumarate, 2-methyl-3-pentyl fumarate, 3-
methyl-3-pentyl fumarate, 2-methyl-2-pentyl fumarate, 2,3,3-
trimethyl-2-butyl fumarate, 2,4,4-trimethyl-1-pentyl
fumarate, 2,3,4-trimethyl-1-pentyl fumarate, 3,3,4-trimethyl-
l-pentyl ~umarate and 2,3,4-trimethyl-2-pentyl fumarate.
30 to 70 parts ~y weight, and preferably 40 to
60 parts by weight, of tne monomer whose homopolymer has a
glass theoretlcal temperature of more than 30C. ~preferably
30 to 15UC.), based upon the total weight of the binder,
is used. Mlxtures of such monomers can be used in a total
amount within such ranges. Examples of monomers whose
homopolymers have a theoretical glass temperature of more
than 30C. are acrylonitrile, vinyl chloride, vinyl acetate,
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lOSZOZ9
chloroacetlc acld vinyl ester, trifluoroacetlc acid vlnyl
ester, venzoic acid vinyl ester, styrene,~ -methyl-styrene,
vinyl toluene and methacrylate esters having 1 to 4 carbon
atoms in the ester radical, such as, methyl methacrylate,
ethylmethacrylate, propyl methacrylate, butyl methacrylate,
isopropyl methacrylate and isobutyl methacrylate.
The glass temperatures represent an additional
criterlon and have been described by Flory in "Princlples
of ~olymer Chemistry", pages 56 and 57, tlY53J, Cornell
University Press. Although actual measurement of the qlass
bransition temperature is preferred, it can also be calculated
as described by Fox in Bull. Am. Physics Soc., 1, 3, page
123 (19~6).
0.~ to ~ parts by weight, and preferably 2 to 4 parts
by weight, of the polymerizable acid or a salt thereof, based
upon the total weight of the binder is used. Mixtures of
such polymerizable acids and/or salts thereof can be used in
a total amount within such ranges. ~xamples of polymerizable
acids are: the olefinic acids having ~ to ~ or more carbon
atoms, such as, acryllc acid, ~-methacrylic acid, crotonic
acid, methacrylic acld, lsocrotonic acid, vinylacetic acid,
~-pentenoic acld, allylacetic acid, angellc acid, tiglic acid,
and isohydrosorbic acid; unsaturated di~asic (dicarboxylic)
acids having 4 to 8 or more carbon atoms, such as, maleic
acid, fumaric acid, citraconic acid, mesaconic acid, itaconic
acid, methylmaleic acid, methyl itaconic acld and glutaconic
acid. Anhydrides of such polymerlzable acids, such ~s,
crotonic anhydride, methacrylic anhydride, itaconic anhydride,
- citraconic anhydride and maleic anhydride can be used. Salts
of such polymerizable acids can ~e, for example; amides, such
as, acrylamide crotonamide and methacrylic amide; halides such
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lOSZ029
as, acrylyl chloride, crotonyl chloride, tiglyl chloride,
fumaryl chlorlde and itaconyl chloride; and nitriles, such as,
crotononitrile, metnacrylonitrile acrylonitrile, allylacetoni-
trile fumaronitrlle. Semiesters o~ such polymerlzable acids
having 1 to 1~ carbon atoms ln the ester radical can be used,
and examples of such semiester groups are methyl, ethyl,
pentyl, nonyl, isopropyl, decyl, t.-butyl, octadecyl and iso-
butyl. Mixtures of the above can be used.
The polymerizable acids can be partlally neutrallzed
tprior to additlon to the reaction mixture) by means of a
water soluble tertiary amine. Examples of such tertiary
amines are the water soluble trialkyl amine (having 1 to 8
carbon atoms in each alkyl group), such as, tri-n-butylamine,
trimethylamine, triethylamine, and tri propylamine; and
the water soluble trialkanol amines (having 1 to 8 carbon
atoms), such as, triethanolamine and trisopropanolamine.
Mixtures of the tertiary amines can be used.
2 to 35 parts by weight, and preferably 10 to 25
parts by weight, of the reactive monomer, based on the total
weight of the binder, is used. ~xamples of the reactive
monomers are: (i) monomers having at least one hydroxyl
groups, such as, (a~ glycol monoacrylate, monopropylene glycol
acrylate, glycol monomethacrylate, monopropylene glycol
methacrylate, glycol monocrotonate, glycerol methacrylate,
glycol monoisocrotonate, monoacrylate, glycol monovinylacetate
butendiol-1,3-monoacrylate, butandiol-1,3-monomethacrylate,
trimethylene glycol monoacrylate, trimethylene glycol
~ monomethacrylate, the monoacrylate of 1,5 pentandiol and
the monoacrylate of 1,3-butandiol (the above are the reaction
products of dihydric alcohols having 1 to 8 carbon atoms or
of trihydric alcohols having 1 to 8 carbon atoms and olefinic
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105Z029
acids havlng ~ to ~ carbon atoms), and (b) hydroxy maleic
acid esters, dihydroxy malelc acid esters and hydroxy fumaric
acid esters the ester radicals thereof having 1 to 18 carbon
atoms - examples of such ester groups are ethyl, methyl, propyl,
isopropyl, isobutyl, hexyl, nonyl, octyl, tridecyl and pentyl
(the above are esters of unsaturated dibasic acids having 4 to
8 carbon atoms in the acid group); (ii) chloro hydroxy ester
unsaturated acids, such as, 3~ chloro-2-hydroxy)-propyl-
acrylate-3-(l-chloro-2-hydroxypropyl1-lsopropylmaleinate;
(iii) monomers with functional amide groups, such as, acrylic
amide, maleic acid monoureide, and with methylolized amide
groups, such as, N-methylol methacrylic amide, or their
disgulsed methylol derivatives, such as, n-butoxymetnylene-
acrylic amlde; (iv) monomers with functional allyl groupings
such as methacrylic acid allyl ester, maleic acid dlallyl
ester; and (v) monomers with functional aziridinyl groupings,
such as 2-(1-aziridinyl) ethyl-methacrylate.
The viscosity of the lattices usable as binders
for coatings can be adjusted subsequently (a~ter production)
with various thickening agents. Colloids such as, polyvinyl
alcohol and water soluble modifications thereof, water
soluble cellulose derivatives, such as hydroxy, ethyl,
hydropropyl, methyl, ethyl, and carboxymethyl cellulose,
water soluble polysaccharides and derivatives thereof and
polyacrylic acid and water soluble derivatives of it are
usable as.the thickening agent.
The dispersions obtained a~ter the polymerization
are adjusted wlth a water soluble tertiary amine (such as,
triethylamine, dlmethylamlnoethanol, triethanol amine or
any of the above described water solùble tertiary amines)
to a pH be~ween 5 and 9, and preferably a p~ of 6. The
lOSZ029
dispersions a~e then aged in order to improve their capability
to ~e plgmented and their storage stabllity by an approxlmate
10 minute heating to 50 to ~0 C.
Tne a~ueous dispersion products of this invention
can be plgmented wlthout any further addition of auxiliary
dlspersing agents. Whenever pigments are used, the ratio
of pigments to the other solid substances o~ the coating can
be varied within a wlde range depending on the pigment used
and the special type ot application. Thus the ratio of
pigment to the other solid substances of the coating can be
from 1:20 to 20:1. The clear coatings are particularly
valuable as cover coatings which are used to protect decorative
first coatlngs without impairing the decorative effect. Since
the coatings according to this invention are entirely clear
` and transparent, are hard as well as tough, have a nigh
luster, have excellent resistlvity against solvents and water,
and have a high degree of adhesiveness to a large number of
surfaces, they are superbly suitable as overprlnt finishes.
The self-cross-linking lacquers according to this
invention can be applied to a large number of substrata with
the slngle restraint that the substrata ~e able to resist
the hardening process which is essential for the production
of the coatings. Metals, such as, iron, steel, chrome-plated
steel, tin-plated steel, alumin~m, copper, bronze and brass
in the form of sheet metal or in a rolled up form, are
excellent substrate for the coating compounds according to
this invention. Ceramic surfaces, and in a few cases wooden
- surfaces, are also suitable as su~strata.
Once applied, the self-cross-linking lacquers are
hardened by a heat treatment which is typically a baking for
2 minutes at 180 to 260C. - the heat treatment having a tlme
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lOSZ029
and temperature that varles to the degree needed for each
speciflc self-cross-llnklng lacquer.
For use in the lacquers of this invention, a multi-
plicity of pigments can be used. ~xamples of suitable pigments
are titanium dloxide, iron oxide, chromium oxide, cadmium
oxide, gypsum, calcium silicate, quartz powder, talcum, soot,
calcium ~ rbonate, baryte and organic pigments SUCh as
Pintasol * dyes. Organic and/or lnorganic pigments and/or
extenders can be used.
The coating compounds can be applied ~y any suitable
means or device, such as, with spray gun, brushes or rollers,
or by submerglng and surprisingly by directly rolling to it,
that is to say a single roller applies the coating to the
substratum, whereby it rotates in a bath o~ the coating compoun~.
The applled coating can be hardened in each case by direct
heat action into a smooth film.
The resultlng cured lacquers of this invention excel
by means of thelr hlgh luster, good chemlcal resistance, special
toughness and hardness as well as by their excellent pigment
compatibility and pigment distrlbution. These good character-
istics come about through the fact, that according to theprocess of this invention, very finely distributed dispersion
so-called hydrosoles, are achieved.
Herein the term self-cross-linking means that only
the application of heat is needed to cross-link the lacquer.
* Pintasol is the trademark of ~andoz for organic
or lnorganic pigments in the form of a paste for
paints and lacquers.
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. .,. ,~ ~ . .
105ZOZ9
~ y way ot summary thls invention utilizes ~ blnder
conslstlng essentlally o~:
~ a~ 3~ to /0 parts by weight of a monomer or of
a monomer mixture, whereby the theoretical glass temperatures
o~ the homopolymer lles below 10C,
(b) 30 to 70 parts by weight o~ a monomer or o~ a
monomer mixture, whereby the theoretical glass temperatures
of the homopolymer lie above 30C,
(c) 0.~ to ~ parts by weight of a polymerizable
acid or its salts,
(d) 2 to 35 parts by weight of a reactive
monomer, and
(e) O.S to S parts by weight of an alkali or ammonium
salt of a polymerlzable sulfonic acid.
In this specification, including the examples and
claims, percentages, parts, ratios and proportions are on a
weight basis, unless otherwise stated or obvious to one
ordinarily skilled in the art.
General polymerlzation process
The appropriate portion of the monomer mlxture is
inserted into an agitator autoclave having heating and cooling
means as well as means for adding doses (can be on a batch,
semi-continuous or continuous basis) of further materials.
Then a portion of the aqueous phase, in which the emulsifiers
and the persulfate are dissolved in, is inserted into the
autoclave. After flushing the autoclave with nitrogen, a certain
a unt of the monomer mixture is pre-emulsified, the temperature
is adjusted to the desired temperature (20 to 23C), and the
polymerization is started by dosing in ~adding on a continuous
basis) an aqueous solution of ascorbic acid and iron ~II)-salt.
-18-
.
105ZOZ9
At the same time a sudden temperature rise of 1 to 2 C. will
be observed, wnereupon the dosing speed of the reduction agent
is throttled. At the same tlme, the feed o~ the remaining
monomers (which are being dosed in) can be balanced with the
dosing speed of the reduction agent while making use of the
cooling capacity of the reactlon vessel in order to maintain
the pre-selected constant polymerization temperature (+ 1C).
Polymerizable components which are not monomer-
soluble, for example, certain acids, reactive monomers and/or
emulslfiers, are added by doses in aqueous solution concurrently
with and parallel to the addition remalning monomer mixture.
The polymerizable acids can be partially neutralized prior to
addition with a water soluble tertiary amine.
If the introduction of the reactive methylol grouping
is accomplished ln sltu, then the quantity of formal~ehyde
required for this purpose is placed in the autoclave the aqueous
phase as such is being prepared and the monomer amide in
question is dosed as needed.
EXAMPLE 1
Uslng the general polymerization process, 'he
following starting mixture was polymerized in a 2-liter agitator
autoclave:
1. mlxture;
de-ionized wat~ 410 gm.
Fenopon C0-436 ~ (50%) 5 gm.
methallyl sulfonate (sodium salt) 1 gm.
potassium persulfate (KPS)0.8 gm.
2. dosing materials
2.1 aqueous solution:
de-ionized water 100 gm.
acrylic acid (adjusted with 8 gm.
trlethylamine to pH 3)
N-methylolacrylic amide32 gm.
methallyl sulfonate 0.5 gm.
* Fenopon C0-436 is the trademark of GAF for an ammonium
salt of nonylphenoxypoly-(ethyleneoxide)-ethanolsulfate.
105ZOZ9
2.~ monomer phase:
ethylacrylate ~of these, 20 gm. are~ 160 gm.
styrene ~inltia11y placed in ~ 122 gm.
~the autoclave J
2.3 activator solution:
de-ionized water 50 gm.
ascorbic acid 0.3 gm.
iron (II)-sulfate (FeS0 7H 0) 0.05M
~ aqueo4s solution 0.5 gm.
Fenopon C0-436 ~J'
polymerization temperature 27C.
duration o~ reaction (= duration of
supply of the monomers) 4 hrs.
pH adjusted with triethylamine to ~
A series of additional experiments (i.e., Examples
la to 5) was carried out according to Example,l, except that
the composition and the reaction conditions were varied
according to Table 1.
- In page B of Table 1, characteristics of the dis-
persions obtained are listed. The conversion in each case
were more than 99.5 percent. 'l'he content of solid substance
was between 3~ and 40 percent.
Table 2 shows the technical characteristics and
proper~ies of the lacquers of the pigmented baked films.
EXAM~LE 2
'rhis experlment was carried out in a 5-liter agitator
autoclave and at~the same time five times the quantity of the
original mixture in Example la was polymerized. The initiator
quantity used was reduced to about one half.
~XAMPLE 3
As compared to Example la the ratio of styrene to
ethylacrylate was increased and an additional emulsifier was
: - also used in the initial mixture.
EXAMPLE 4
'l'he ~ormaldehyde was inserted in situ into the
acrylic amlde and maleic acid monoureide. 'l~he dosed portion
-20-
lOSZ~
o~ methallyl sultonate was lncreased.
EXAMPLE 5
The emulsifier mixture corresponded to Example
3. As compared to Example la, polypropyleneglycolmsnsacrylate
was used as an additional cross-linking component, and the
, addition of formaldehyde to the acrylic amides was done as
- in Example 4. The dosed portion of methallyl sulfonate
corresponded to that of Example 4.
lOSZO;~9
TA13I,~ xamples la - 5
~xample No.
_ . _
la 2 3 4 5
A.l. Mlxture:
de-ionized water 27.5 120,5 123.9 107.7 106.~
Fenopon C~-436 ~ 0.77 0.73 0.75 0.69 0.67
Tensopol A ~ 0.75 0.67
methallylsulfonate U.31 0.29 0.3 0.28 0.27
KPS 0.~5 0.15 U.24 0.~2 0.22
tormaldehyde(100~) . 4.14 5.15
2. dosing
2.1 aqueous phase:
de-ionized water 30.9 ~0.7 29.9 27.6 27.0
acryllc acid ~pH
adjusted) .41 2.48 2.40 4.14 4.U5
N-methylolacrylic
amide 9.89 9.46 Y.73
acryllc amide 8.5 8.38
maleic acid monoureide 2.76
Methallylsulfonate0.15 0.15 0.15 0.55 0.54
2.2 monomer phase:
ethylacrylate 9.5 49.7 40.5 47 44.6
styrene 7.7 37.9 46.8 ~5.Y 34.0
polypropyleneglycol-
monoacrylate 8.1
2.3 activator solution:
de-ionized water 5.5 14.6 15.0 13.8 1~.5
ascorbic acid .09 0.04 0.09 0.08 0.08
iron (II) sulfate~~
(Fe$~4.7H2O) l
0.05 M aqueous (.150.080.15 0.150.15
solution ~ J
~0 Fenopon C~-436~-~0.030.030.03 0.030.03
polymerizaOtion temp-
erature (~ C) 27 ~7 27 21 ~1
reaction duration
(- duration of supply~
of the monomers) (hrs~4 43 4 ~
B solid matter (~)6.335.436.8 3Y.439.8
monomer residue (%
related to dispersion) U.35 0.190.30 0.280.22
viscosity Din-4-beaker
(sec) 28.6 2119.2 1716.8
P~ 6 6 ~ 6 6
Note: All numbers ln Ta~le 1 are amounts expressed in grams
- unless otherwise stated.
* Tensopol A is the trademark of Tensia S.A. for a
sodium lauryl sulfate.
-22-
lOSZOZ9
The dlspers1ons produced accordlng to Examples la
to 5 were each grounded in a ball mill with titanium dloxide
(rutile) in a ratio of 1:1, related to the content of the
dispersion of solid substance.
The pigmented backing varnish were applied witn an
80 spindle as films on chromatized alumlnum (0.6 mm thickness)
and then ~aked for 2 minutes at 180 to 260C. Highly
lustrous lacquer coatings without bllsters were obtained each
having excellent levelling and very good lacquer-technical
characteristics (properties).
-23-
105Z029
Table 2
(Characteristics of the pigmented, baked lacquers)
_ . _ r_ _ ~
~ . .
~ ,, ~ ~ ~ ~a
o ~ t) o o o
.,~ ~ ~ ~ o o o o
J~
. u~ u~
~1 ~ .~~ ~ ~ ~ ~~ ~ ~ ~ ~1
O O ~ ,1 O O O ~ JJ O O O h O ~
u~ ~ OO O ~ 1 OOO O O O
~ ~ ~~u~ m ~~ ~ ~
.. O . . ,
:~ J~ J~) ~ a
O ~ o t) O O
a~ ~ o o o o~
O ~ U~ U~
U~ ~ ~~ ~ ~ 1 ~~1a ~ ~ :~
a~ E~ O O O ~ ~ O O O ~-1 O
o c~ oo o ~ ~ ooo a~ o a
U ~ ~ ~ __ . . _
E~ ~ .
Q ~ ~ ~ ~ ~ ~
. ~ _ _
,o ~
~ o o~ o o ~ o
.__ _.... ___ . ,
a)
~ O~P
::1 ~ oo cs~ o o r~ ~ 1~
n ~ ~ ~o ,n J~ n ~n n
. . ._ _
~ u~ . _
~ O ~
~
h t~ ~ O o o n u~ ~ u~ N C17
O n~ O O Q) Lt~ ~D ~r ~ N In ~O :~ ~
p~ 0 ~ . __ _l l
~ ~ .
.c a) ~ Itl ~ _l ~ ~ ~1 ~ et~ ~
E~ ~ 0 ~1 N N N N N N N N N
l l l l l l l l
. O _1 0 0 O O _1 N N
. N ~ N N N N N N N .
Y ~ ~ O O O O O O O
~ ~ O ~ ~o ~ o ~ ao
m ~ N N N N --1 ,_1 N N N
_ _ _.. ~ ~ ~ , . _ ~ I
o~
ut
. ~ 3 ~ ~ ~ .
~1 ~1 N ~ ~1 ~ ~ ~r Irl
o a~ o~ a o ~1) ~)
_, ~, ~ a) ~ ~ ~t
~ ~ ~ ~ o u~ ~ ~
X X X Q~ X X X
~1 ~1 W ~ u~ h I ~1 , _ ~ .
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