Note: Descriptions are shown in the official language in which they were submitted.
Q~.
This invention relates to a process for the production o~ polymer dis-
persions in which new a~o-di-isobutyric acid-(N,N'-hydroxyalkyl)-a~idines or
their salts are used as water-soluble polymerisation initiators, and to the use
of the polymer dispersions obtained as aqueous coating agents in ccmbination
with products corltaining methylol ether groups or in the production of aqueous
coating agents.
US Patent No. 2,599,299 describes a process for producing the dihydro-
chloride of azo-di~isobutyric acid amidine.
In addition, German Auslegeschrift No. 1,693,164 describes a process
for producing acid-free azo-di-isobutyric acid amidine. In this known process~
ho~ever, special precautions have to be taken to ensure that the water-moist pro-
duct does not decompose.
The use of these compounds as polymerisation initiators has also been
described (cf. US Patent No. 2,599,300~.
However, they have never been adopted for use on a commercial scale
both on account of the instability of the initiators themselves and on acc~unt
of the corrosion and coagulation problems involved in their use as initiators.
This is attributable above all to the hydrolysis of the free amidine group which
leads to ammonia, amide groups and ammonium salts groups:
~ ~ NH -~ R-C ~ H2O ~ 4
NH2 2 O
R = residue of the initiator molecule.
Although the solubility of the above-mentioned radical formers in
water is basically a highly desirable prcperty for polymerisation in aqueous
suspensions or emllsions, the appearance of salts freq~lently interferes with the
polymerisation reaction. In the case of sensitive emulsions, this can give rise
"~ ~
~3~3~
to premature undesirable coagulation of the emulsions. Furthermore, the
incorporation o salt-like groups in the polymer also causes problems in man~
cases and can have an e~tremely adverse ef~ect upon the properties of the
poly~er.
It has now surprisingly been found that ~le disadvantages reerred to
above can be obviated by using the new azo-di-isobutyric acid-(N,N'-hydroxyaIkyl)-
amidines corresponding to the formula (I):
HO-R-N ~ , 3 , 3 ~ N-R-OH
C-C-N=N-C-C (I)
\
HO-R'-N CH3 CH3 N-R'-OH
X X
in which
R and R', which may be the same or different, represent linear or
branched alkyle~e radicals oontaining from 2 to 4 carbon atoms, and
X rep~esents hy~rogen or -R'-OHt
as polymerisation initiators. In additicn, polymers having very special and
desixable pxopexties through incorporation of the hydrophilic hydroxyalkyl
groups are obtained.
In the formula (I), R and Rl preferably represent linear or branched
alkylene radicals containlng 2 or 3 carbon atams such as -C~I2-CH2--; -CH2-C12-C~2-
or C~I3 and X represents hydrogen or R'-OH.
CH --CH--
More particularl~, R and R' in the formula (I) are the same and repre-
sent a linear alkylene ra~ical containing 2 car~on atoms (= ethylene radical)
whilst X represents hydrcgen or a ~-hydroxyethyl radical.
m e present invention relates to the use of the azo-di-isobutyric acid-
(N,N'-hydroxyalkyl)-amidines corresponding to the formula (I) above as radical
)3~
formers in the polymerisation of unsaturated ccmpounds and/or in the crosslink-
ing of polyunsaturated polymerisable co~pounds.
The azo-di-isobutyric acid-~N,N'-bis-hydroxyalkyl)-amidines and azo-di-
isobutyric acid-(N,N'-tris-hydroxyaIkyl)-amidines used according to the inven-
tion may be produced by
A) reacting azo-di-isobutyric acid amidine unsubstituted on th~ N-atoms,
or the amidine substituted on the N-atoms by 1 -to 5 hydroxyalkyl
radicals containing from 2 to 4 carbon atoms, with alkylene oxides
(C2 C4), or
B) rea~ting azo-di-isobutyric acid iminoalkyl ethers corresponding to the
general formula (II) below with monoalkanolamines or with mLXture of
manoaIkanolamines and dialkanolamines.
HN CH3 CH3 NH
~ C-C-N=N-C-C ~ (II)
RD CH3 CH3
In the formula (II), R represents lower alkyl radicals co.ntaining -from 1 to 4
carbo.n atoms.
The reaction of azo-di-isobutyric acid imincmethyl ether with mono-
ethanolamine [reaction scheme (IIIa)] and ~he reaction of azo-di-.isobutyric acid
iminoethyl ether with a mixture of mono- and di-ethanok~mm e ~reaction sche~.e
(IIIb)] are shown by way of example in the following equations:
~f
i
3~
( IIIa)
HN CH CH NH
~, 3 ,
C-C-N=N-C-C ~ 4 N~I2 C~2 C~2 0~1
CH30 CH3 CX3 OC~3
CH3 CH
HO-C~2~CH2-N~ I 1 3 N-CH -CE -OH
7 C-N=N C-C ~ 2 2 ~ 2 NH3 + 2 CH30H
H-C~2 C~ -N CH3 CH3 -CH2-CH2-OH
.
( IIIb )
CH3 CH
I ~ ,C~I2- CE~ OH
~ C-C-N=N-C-C ~ , 2 NH -CE -CH -OH + 2 E~N
C2H5-O IH 1~ C2~I5 2 2 2 CH2-CH2-OH
CH CH
HO- C~l2- CH2-N I ~ ; N- CH~- CH~- OH
~ C-C-N=N C-C \ ~ 2 NH3 ~ 2 C H -OH
H-CH2-CH2-N I~I3 IH N\ CH2 CH2 OH 2 5
CH2 CH2 C~12-CH2-OH
lt is readily possible t,o produce azo-di-isobutyric
acid-(N,N'-bis- or ~,N'-tris-hydro~yalkyl)-amidines by
initially subjecting azo-di-isobutyric acid amidine to a
partial reaction with an alkylene oxide, followed by
condensation with a mono- and/or di~al~anolamine up to the
required clegree o~ substitution, or vice versa~ On the
other hand, the imino groups of the azo-di-isobutyric
acid iminoalkyl ether may initially be co~pletely or
partly reac-ted with an alkylene o~ide ancd the alkyl
ether gro-ups and residual imino groups; i~ any, subsequerltly
Le A 19 05B
condensed with a mono- and/or di-alkanolamine to -~orm
the N,N'-~is-(hydroxyalkyl)- or N,N',N'-tris-(hydroxy-
alkyl)amidine o~ azo-di-isobutyric acid.
The azo-di-isobutyric acid-(N,N'-bis- or N7N',N7-
tris-hydroxyalkyl)-amidines are preferably obtained by
reacting azo-di~isobutyrio acid iminoalkyl ether with
mnnoalkanolamines or with mixtures o~ monoalkanolamines
an.d dialka~olamines (molar ratio 1:1).
The addition reaction with the alkylene o~ides and
the condensation reaction with mono- and/or dialkanol~
am.ine is carried out at 0 to 50~ and preferably at 20
t~ 45C. The reactions may be carried out in the
absence of solvents or in the presence of organic
solvents which are inert to the reactants under the
reaction conditions, ~or e~ample in alcohols such as
methanol or ethanol; in ethers such as diethyl ether
or dioæane; in ketones such as acetone or ethylmethyl
ketone; and also in aliphatic or aromatic hydrocarbons.
The reactions may be carried out in the absence of applied
pressure or under pressures of up to 50 bars.
Suitable alkylene oxides are ethylene oxide,
propylene oxide, 1,2-epo~y butane, 2,3-epoxy butane
and 1,2-epoxy-2-methyl propane, pre~erably e-thylene
oxide and propylene oxiae and, more particularly~
et]lylene oxide.
The ~ollowing amines may be used for the reaction
wiGh the iminoalkyl ethers: ethanolamine, diethanolamine,
l-amino-2 propanol, bis-(2-hydroxypropyl)-amine, 1-
amino-3-propanol, bis-(3-hydroxypropyl)-amine, isopro-
3o panolamine, diisopropanolamine, 1-amino-4-bu~anol, bis-
(4--hydro~ybutyl)-amine, 1-amino-3 butanol, bis-(3-
hydroxybutyl)-amine, l-amino-2-butanol, bis-(2-hydroæy-
butyl~ amine, l-amino-2-methyl-2-propanol, bis-(2-hydroxy~
2-methyl-propyl)-amine~ 2-amino-2-methyl l propanol, bis-
Le A 19 058
~.
~L~3~
t~ono-hYdroxy tert.-butyl)-amine, l-amino-2-~ethyl-3-propanol and bis-(3-hydroxy-
2-methylpropyl)-amine or mL~tures of the above-men-tioned amines.
It is preferred to use ethanolam m e, diethanolamune, l-amino 2-pro-
panol, bis-(2-hydroxypropyl)-amlne, 1-amino-3-propanol, bis-(3-hydroxypropyl)-
am me, isopropanolamine, diisopropanolamine or mixtures -~hereof; ethanolamine or
diethanolamine or mlxtures thereof are particularly preferred.
me alkylene oxides are preferably used in such quan-tities that
approxImately 1 mole of alkylene oxide is present per ~mo group of the
amidines or iminoethers and approximately 2 moles of alkylene oxide per amino
group of the ~midines. m e alkanolamines and diaIkanolamines are preferably
used in a quantity of 1 mole per imino, amino or alkylether group of the
amidines or iminoethers.
The reaction of iminoaIkyl ethers with amines to form amidines is
known in principle from the literature (cf. Methoden der organischen Ch~mie,
Houben-Weyl, 4th Edition ~1952), Vol. 8r page 703); the hydroxyalkylation of
amidines with alkylene oxides is also kncwn (cf. US Patent Nc. 2,980,554, column3, lines 41 to 43).
Th~ production of the azo-di-isobutyric acid iminoalkyl ethers used as
starting materials is also known from the literature and may be carried out~ forexample, by the process according to GQrman Offenlegungschrift No. 2,242,520
(pages 31 to 32).
me following are mentioned as examples of the azo-di-isobutyric acid-
(N,N'-hydroxyalkyl)-amidines pro~uced by the cited processes:
azo-di-isobutyric acid-(N,N'-bis-2-hydroxyethyl)-amidine,
azo-di-isobutyric acid-(N,N'-bis~3-hydroxypropyl)-amidine,
azo-di-isobutyric acid-(N,N'-bis-2-hydrDxypropyl)-amidine,
azo-di-isobutyric acid-(N-2-hydroxyethyl-N'-3-hy~roxypropyl)-amidine,
-- 7 --
.
~.3~
azo-di-isobutyric acid-(N-2-hydroxyethyl-N'-2-h~droxyprcpyl)-~midine,
azo-di-isobutyric ad d-(N,N'-bis-3-hydroxybutyl)-amidine,
azo-di-isobutyric acid-(N,N',N'-tris-2-hydroxyethyl)-amidine,
azo-di-isobutyric acid-(N,N',N'-tris-3-hydroxypropyl)-amidine,
azo~di-isobutyric acid-(N,N',N'-tris-2-hydroxypropyl)-amidine,
azo-di-isobutyric acid-(N-2-hydroxyethyl-N',N'-bis-3-hydroxypropyl)-amidine,
azo-di-isobutyric acid-(N-2-~lydroxyethyl-N',N'-bis-2-hydroxypropyl)-amidine,
azo-di-isobutyric acid-(N-3-hydroxypropyl-N',N'-bis 2-hydroxyethyl)-amidine, and
azo-di-isobutyric acid-(N-2-hydro~ypropyl-N',N'-bis-2-hydroxyethyl)-amidine.
The azo-di-isobutyric a~id-(N,N'-hydroxyalkyl~-amidines are obtained
in a smooth high-yield reaction under the above-mentioned reaction conditions
and are water-soluble, yellcw to yellow-orange oils. m ey may be used as
radical formers in the polymerisation of unsaturated compounds. They may also
be used in the crosslinking of, or in crosslinking pro oesses involving, unsatur-
ated ccmpoun~s or prcducts, optionally with foaming. They are also suitable for
use as blcwing agents in the production of foams.
me use of the azo-di-isobutyric acid-(N,N'-hydroxyalkyl)-amidines in
the production of aqueous polymer dispersions is described in the following and
in Examples 7 to 19.
Polymer dispersions are frequently prepared for use as coating mate-
rials or, in ccmbination with pigments and fillers, as coatings for wof~d, metals,
ceramics, plastics materials and the like. If the coatings are to adhere firmly
to the substrate, even in a moist atmosphere or in the presence of water, the
content of water-soluble salts in a polymer film has to be as lcw as possible.
m e salts not only impair the adhesion of the films to the slibstate,
but they also pramote separation of the film from the surface. 1~is is part-
icularly critical when the polymer is hard and substantially non-tac~y. In this
.~
.3~ a.;~
case, small quantities of salts have a particularly serious affect upon the
ooalescence of the latex particles. In the presence of water, the salts passing
into solution build up osmotie pressures at the diffusion interfac~s of the
latex partieles which can give rise to chaLking of the binder and can cause it
to soften to the point where it dissolves.
~ ccordingly, it has been proposed to earry out polymerisation with
hydrogen peroxide or with water-soluble, non-salt-like derivatives of perhydrDl,
sueh as tert.-butyl hydroperoxide. However, the latices obtained in this wav
show very poor ion and shear stability. In addition, it has frequen-tly been
reccmmended to carry out polymerisation with very small quantities of per-
sulphates. Unfortunately, this leads to substantially non-reprodueible latices
which, in some cases, ean completely coagulate.
It has now been found that polymer dispersions ean be obtained without
the æ sistance of inorganie salts whieh adversely affect the adhesion and resist-
ance to water of the polymers, providing azo-di-isobutyric
-- 10 --
acid-(N,N'-hydro~yalkyl)-amidines corresponding to th~
~ormula (I) above are used a~ polymerisation initiators
instea~ of the usual alkali metal or ammonium per~
sulphates or other salt-like peroxy compounds.
These amidines are a valuable addition to thc
already known water solubl~ a,a'-a~o (~-methyl-y-
sulpho)-butyric acid dinitrile (IV) (c~. German
Auslegeschri~t No. 1,111,395j, to the azodinitrile~ o~
the a,a~-azo-(a-methyl-r-diethylamino)-butyric acid
dinitrile type (V) (cf. US Patent No. 2,605,~60) and o.
the ~ y'-azo-(~-cyano)-valeric acid = ~,a'-azo (~
meth~l y-sulpho)-butyric acid dinitrile typs (VI) ~c~
US Patent No. 2,520,338) or, ~inally, to the 2,2'-a~o
(2-methyl-propion-amidine), (VII), (cf. US Patents hro~i.
2~599,299 and 2~599,300).
CH3 CH3
H03S-CX2~CH2-C_N=N_C_cH2_cH2_so3H (I~)
C--N C-N
C2H5 ~ , 3 , 2 f 2~5
~ H2 CH2-c~N=N-c-c~I2-cH2-N
C2H5 C-N C_N C2.H5
, 3 , 3
E00C-CH2-CH2_C_N=N_,C_GH2~cH2 (VI)
C_N C_N
HN ~H
_ _ ' ~ (VII)
C-C-N=N-C-C \
~I2N 3 3 N~2
~!~ .
The amidines corresponding to the formula (VII~
are generally used in the form of hydrochloric acid
salts (cf. US Patent No. 2,599,300). However, they have ~ -
to be used in ice-cooled form in order to a~oid undesir-
able decomposition and hydrolysis (cf. the example of
the production of a polyethylene latex with the amidine
of an azodinitrile in: Houben-Weyl, Methoden der
Organischen Chemie, 4th Edition, Vol. XIV/l (1961),
pages 222 et seq). However, chloride io~s are
particularly troublesome in a latex intended for
corrosion prevention, because they accelerate rust
formation to a considerable e~tent. In addition, the
amidines of the formula (VII) can only develop a
favourable e~fect in a neutral or acid mi~ture.
By contrast, the initiators~~use~ acc_rding to_the
invention corresponding to the formula (I) above are
stable in a~ueous solution at room temperature. They
are active both in acid and in alkaline medium and are
highly soluble in water.
The compounds of the formula (VI) are only soluble
in an alkaline or neutral medium and are unsuitable for
monomers which are to be polymerised in an acid or
midly acid medium.
The initiators according to -the invention have
a major advantage over the compounds corresponding to
the formula (V), i.e. they contain in the molecule free
OH-groups which are incorporated at the beginning and
end of a polymer chain. These OH-groups provide ~or
improved adhesion~ are accessible as reactive groups
~or crosslinking reactions and are desirable ~or
numerous applicationsO
Although the compounds corresponding to the formula
(IV) give stable latices, the sulpho groups which they
introduce into the polymer adversely affect the resistance
Le A 19 05~ -
to Water of the ~ilms obtam able from dispersions ~uch as these.
In addition, the acid groups of the initiabors corresponding to the
formula (IV) have to be buffered with bases so that, ultimately, they
do not have any particular advantages over the potassium or ammonium
persulphate normally used.
m e initiators used according to the mvention corresponding to the
formula (I) ~ay be used m alkaline medium ~nd also in acid medium.
Even when used in small quantities/ they lead to high ~ields of
polymer, as can be seen from the Examples.
It has proved to be particularly advantageous to use the
initiators correspondiny to the formula (I) in the form of salts or
adducts of polymerisable ad ds. This measure enables polymerisation to
be carried out at any pH-values in the range of from about 3 to 9.
Examples of suitable polymerisable acids are saturated and mono-
olefinically unsaturated sulphonic and carboxylic acids particularly
~hcse containing from 3 to 5 carbon atoms, such as acrylic acid, meth-
acrylic acid, crotonic acid, maleic acid and itaoonic acid. It is also
possible to use semiesters of maleic acid, itaconic acid and fumaric
acid containing from 1 to 18 car~on atoms in the alcohol component.
Vinyl sulphonic acid, methallyl sulphonic acid or 2-N-acrylam~do-2-
methyl propane sulphonic acid may also be used ~or adjus-ting the pH-
value in cases where the electrolyte stability of the dispersions is
of primary importance.
Finally, the alkaline reaction of the initiators correspond m g
to the formula (I) may also be reduced by additions of alk~l sulphonic
acids and/or alkylaryl sulphonic acids, in which case salts with
emulsifier properties are formed. Aliphatic m~nocarboxylic acids
may also be used with advantage.
- 12 -
~3~ 3~
Polymerisation with the initiators cor~espcnding to the ~ormwla (I) is
preferably carried out at tJ3mperatures in the range of frcm 50 to 90C and, m~re
particularly, at tempera-tures of from 50 to 80C, and in the absen oe of applied
pressure or under pressures of up to 200 bars.
The initiators may be used in quantities oE frcm 0.2 to 10 % by weight,
based on the moncmer total. In general, they are used in quantities of frcm 0.3
to 2 ~ by weight. Where importance is attached to an increased incorporation of
hydroxyl groups and to a low molecular weight, correspondingly higher quantities
are used.
The initiators may be added in various ways during the polymerisation
reaction. The initiator may be added linearly at a rate which just compensates
for the decomposition of the initiators at the particular polymerisation tempera-
ture applied~ However, the entire quantity of initiator may also be introduced
at the outset. Alte m atively, most of the initiator may be kept for the last
fractions of monomer. The products obtained dif~er in their molecular weight
distribution and in their properties according to the manner in which the
initiator is added.
In the case of dispersions which are to be used as binders for the pro-
duction of aqueous stoving lacquers, it is favourable, for example, to add most
of the OH-group-containing initiators of the formula (I) towards the e~nd of the
introduction of the monomers so that polymer fraetions of high molecular weiyht
and low in hydroxyl groups are obtained at the beginning of polymerisation~
whereas low molecular weight polymer fractions which improve levelling and gloss
and which, by virtue of their higher terminal hydroxyl group content, can be
effectively crosslinked ~ith formaldehyde resins are obtained towards the end of
polymerisation.
It has now surprisingl~ b~en found that the stability of the polymer
- 13 -
i~
dispersions produoed with the initiators according to the invention is extremely
good, even when aN onic emulsifiers are used, although the incorporation of
cationic groups into a polymer can generally be expected to give rise to floc-
culations where anionic emulsifiers are present.
Accordingly, standard anionic, non-ionic or cationic emulsifiers may
be added in addition to the polymerisation initiators according to the invention.
Standard cationic, anionic or non-ionic emMlsifiers are described, for example,
in Methoden der Organischen Chemie, Houben~Weyl, 4th Edition (1961), Vol. XIV/l,
pages 190 - 208 and 4th Edition (1959), Vol. II/2, pages 113 - 138 and in
"Surface Active Agents" by A.M. 5chwartz and J.W. Perry, Interscien oe Pulb. Inc.,
New York, 195B, pages 25 to 171. Ccmbinations of anionic emLlsifiers with non-
ionic emulsifiers in a ratio of from 7:3 to 3:7 (molar ratio) or corresponding
cQmbinations of cationic emulsifiers ~ith non-ionic emulsifiers are also
possi~le.
However, polymerisation may also be carried out in the absen oe of
standard emulsifiers in cases where cumpounds which form oligomers with an
emulsifier-like effect or which perform a dual function of emulsifier and
monomer are used.
Cc~pounds such as these are, for example, alkali metal or ammonium or
amine salts of maleic acid semiesters with an alcohol residue containing more
than 5 carbon atoms, for example maleic acid cyclohexyl semiester/maleic acid
dodecyl semiester saLts. ~k~ever, polymerisation may also be carried out in the
absence of emulsifiers using protective colloids, such as polyvinyl alcohol for
example.
Suitable polymerisation nomers are any unsaturated m~nomers which
can be polymerised in the usual way with æodiisobutyronitrile in nQn-aqueaUs
solution, for example, styr~ne, ~-methyl styrene, butadiene, acrylic acid esters
- 14 -
'~
~l~3~3~
containing from 1 to 8 carbon atoms in the alcohol component, methacrylic acid
esters contaim ng frcm 1 to 8 carbon c~toms in the alcohol component, acryloni-
trile, methacrylonitrile, vinyl chloride, vinyl acetate, ethylene chloroprene,
etc.
In addi~ion to the above-mentioned m~nomers, water-soluble com~ounds,
such as methacrylic acid, acrylic ad d, maleic acid semiester, itaconic acid and
itaconic acid semiester; acrylamide, methacrylcl~ide, etc., may also be incorpor-
ated in the polymers in smaller quantities. It is also possible to use
comonomers still containing functional groups, for example OH-groups or epoxy
groups, such ~s ~-hydroxyethyl (meth)acrylate, ~-hydroxypropyl-(meth)acrylate,
glycidyl (meth)acrylate and N-methylol- or N-methylol-alkyl ethers of (meth)-
acrylic acid amide.
The p~lymer dispersions may be used for a variety of applications.
The way in which the ne~ initiators act is illustrated in Examples 7 to 19, al-
though the potential applications of the polymer dispersions ar~ in no way
limited by these Examples.
Where the described dispersions are film~forming, they are eminently
suitable for coating, particularly for coatings req~lired to show increased anti-
corrosion activity, improved behaviour in the salt-spray test, firm adhesion,
improved compatibility and crosslinking with products containing methylol or
methylol ether groups, for example with aminoplasts, such as melam me-formal-
dehyde resins or urea-formaldehyde resins, or with ~henoplasts, such as resols.
In the context of the invention, polymers are understoGd to be hom~-
polymers and copolymers. Copolymers are understood to be not only copolymers
with copolymerised monomers in statistical distribution or block copolymers, but
also graft copolymers in which monomers have been grafted anto a preformEd hom~-
polymer or copolymer. Of the copolymers, statistical copolymers are preferred.
- 15 -
~,
~ ~ ~4~ 3'~
m e azo-di-isobutyric acid-(N,N'-hydroxyalkyl)-amidines corresponding
to the formula (I) are also eminently suitable for homogeneous phase poly~.erisa-
tion pro oe sses kno~n per se, i.e. preferably solution and bulk polymerisation
processes. However, polymerisation may also merely begin in homogeneous phase,
the polymer accumulating in finely divided form during the polymerisation reac-
tion (precipitation polymerisation).
Virtually an~ olefinically unsaturated mono~lers which may be used for
p~lymerisation with radical-forming azo ccmpounds are suitable for homopolymerisa-
tion and copolymerisation in homogeneous phase~ The following are examples of
10 monomers such as these:
a) ~ Dnoolefins containing from 2 to 8 carbon atoms, such as ethylene,
propylene, l-butene, isobutylene and diisobutylene;
b) conjugated diolefins containing frcm 4 to 6 carbon atGms, such as
butadiene, isoprene, 2,3-dimethylbutadiene and 2-chlorobutadiene, pre-
ferably butadiene;
c) (me.th)acrylic acid, (meth)acrylonitri].e, (meth)acrylamide, alkyl (meth)-
acrylates containing from 1 to 18 and preferably from 1 to 8 carbon
atoms in the alcohol ca~ponent, such as me-thyl acrylate, ethyl
acrylate, propyl acrylate, isopropyl acryl.ate, _-butyl acrylate, -tert.-
butyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate and the corres-
ponding ~.ethacrylic acid alkyl esters preferably
- 16 -
-~J
.3~ 3:~
- 17 -
acrylic acid, acrylonitrile, acrylamide, methyl-
acrylate~ butyl acrylate, ter-t.-butyl acrylate, 2-
ethylhe~yl acrylate and methyl methacrylate; - _
d) vinyl esters of organic monocarboxylic acid3, the
acid component containing from 1 to 18 a~d pre-fer- -
ably from 2 to 4 carbon atoms, such as vinyl
acetate, and vi~yl propionate, pre-~erably vinyl
acetate;
e) monoole~inically un~aturated halo~enated hydro-
carhons, ~uch as vinyl chlori~e or vinylidene
chloride, pre~erably vinyl chloride;
aromatic vinyi compounds, such as styrene, o- or
~-methyl styrene, ~-methyl styrene~ a-methyl p-
isopropyl styrene, a-methyl-m-isopropyl s-tyrene
and p-chlorostyrene, pre~erably styrene. ~~
In this case, it is pre~erred always to use the
less polymerisable monomers~ such as a-methyl-
styrene and m- or ~-isopropyl a-methyl styrene,
in admi~ture with at least one other o~ the copoly-
merisable mo~omers mentioned.
g) Monoesters oY a,~-monoolefinically unsa~urated mono-
carboxylic acids containing 3 or 4 carbon atoms
with dihydric saturated aliphatic alcohols contain-
ing -~rom 2 to ~ carbon atoms, such as 2-hydroxyeth~l
methacrylate, 2 hydroxypropyl methacrylate, 4-hydroxy-
butyl methac.rylate, 2-hydro~yethyl acrylate, 2-
hydroxypropyl acrylate and 4-hydroxybutyl acrylate~
h) N-methylol ethers of acrylic and methacrylic acid
amide corresponding to the general formula:
2 C - C0 - N - CH2 ~ ~2 (YIII)
R Rl
3o i~ which . ~
R represents hydrogen or methyl,
~13~
18 -
Rl represents hydrogen, alkyl, aralkyl or aryl, and
R2 represents alkyl or cycloalkyl, such as methyl,
ethyl, n-propyl, isopropyl, n-butyl, isobutyl or -~ -cyclohe~yl (cf. German Auslegeschri~t No. 1,035,
363).
It is pre~erred to use the N-methylol methylether
o~ methacrylic acid amide. The monomers o~ group h)
are used and incorporated into the copolymer in
quantities o-f ~rom 1 to 20 ~ by weight, based on
the monomer total.
i) Diesters and monoesters of a,~-monoole~inically
unsaturated C3-C5-dicarboxylic acids, such as
maleic acid, ~umaric acid and itaconic acid with
1 to 18 carbon atoms in the alcohol component, and
7 5 also maleic acid anhydride, maleic or ~umaric acid,
amides of maleic and fu~aric acid~ maleic imides
and unsaturated copolymerisable polyesters which
contain the residues of maleic and/or -~u~aric acid
as polymerisable constituents. Maleic acid anhydride
2G is preferred.
j) Vinylalkyl ethers containing from 1 to 4 carbon atoms
in the alkyl group, such as vinylmethyl ether, vinyl-
ethyl ether, vinylpropyl ether and vinylbutyl ether.
k) Crosslinking monomers containing several unconjugated
olefinically unsaturated carbon-carbon bonds, such
as divinyl benzene, diallyl phthalate, divinyl
adipate, acrylic and/or methacrylic acid allyl ester,
methylene-bis-acrylamide, methylene-bis-methacrylamide,
triallyl cyanurate, triallyl isocyanurate, triacryloyl
-~ perhydroHS-t~iazine, bis-acrylates and bis-methacryl-
ates o~ glycols and polyglycols containing ~rom 2 ~o
20 carbon atoms, such as ethylene glycol di(meth)
acrylate, propylene glycol di(meth)acrylate, butylene
glcyol-1,4-di(meth)acrylate, tetraethylene glycol
di(meth)acrylate, tris-(meth)acrylates o~ trimethylol
~'3L3t~
-- 19 --
propane and glycerol.
~ he crosslinking monomers of group k) are pre~erably
used ~or copolymerisation in quantities of Yrom 0.1 to
12 % by weight, based on the monomer total. They are
incorporated into the copolymer in the same quantities.
In ~ddJtion, primary, secondary or tertiary amino-
alkyl esters o~i (meth)acrylic acid preferably containing
~rom ~ tc 4 carhon atoms in the alkyl group and glycidol-
~meth)ac~ylate may also be used as comonomers and may
optional~y oe crosslinked through the amino or epo~ide
group du;rinc, or a~te!r copolymerisation.
Monomnrs of groups b), c), d), e), f), and i) are
preferahly used ~or copolymerisation.
W~lere polymerisation is carried out in solution,
water ~nd orGanic sc~lvents, ~or example ~imethyl
~ormamide, ter~.-butanol, chlorobenzenes, etc., may be
used as solvents.
The poly~;erisation reaction may be carried out at
temperatures o~ ~rom 50C to 90C and preferably at
temperatu:r~s c-~ from 55C to 75~C, depending on the
decomposition characteristics of the azo compounds
according ~o the invention. The quantity in which
the initiator is us~d may be adapted to the required
molecular weight and may amount to between 0.05 and 10 /0
by weight or more, based on the monomers used~ It is,
of course~ also possible to deviate ~rom these ~igures
on the quantity o~ inifiator and the temperature. The
polymerisation reactions in homogeneous phase may be
carried out in the absence oi pressure or under pressure
of up to 1500 kars.
In every case, the polymers obtained contain at
least 2 hydro~yl groups, emanating ~rom the initiator
~ragments, incorporated at the beginning and end o~ each
polymer chain.
Le A 19 058
~l~ 3~3
- 20 -
'rhe introduction o~ hydroxyl groups at the beginning
and end of polymer chains is oE considerable practical
importance to a variety o~ propertit~s. On the one hand, ~--
the reactivity o~ the poly~ers enables them to be reacted
with compounds which generally react with hydro~yl ~roups
and ~orm wide--mesh ntatworksO Compounds such as these are,
~r example, polyisocyanates~ polyepo~ides, polycarboxylic
acid anhydride, and co~pounds containing mtathylol and/or
methylol ether groups~ In addition, the hydro~yl groups
considerably improve t~le a~hesion of pol~mer films.
Examples 20 to 27 illustrate bulk and solution
polymerisation reactio~ L`.Si~lg the azo~ isobutyric
acid-(N,N~-hydroxyalkyl)~a;~idines corresponding to the
~ormula (I).
The parts and percen-tages quoted in the Examples
are by weight, unless othtarw~se indicated. 'rhe intrinsic
viscosity [~], L dl ] was measured in the solvents
indicated at a temperature o~ 25C.
Production of the a~o-di ~
-
alkyl)-amidines
EXAMPLE 1:
Azo-di-isobutyric acid-~N,N'-~is-2-llydro.Yye-thyl)-amidine:
114 g (0.5 mole) o~ azo-di-isobutyric a~d imino-
methyl ether9 300 ml oE methanol and 122 g (2 moles) o~
ethanolamine were stirred ~or 8 hours a-t 50C. 'rO remove
methanol and ammonia (1 mo~a)~ the mi~ture was distilled
out in a water jet vacuum (12 m~ar) a-t temperatures o~
up to at most 50C, leaving 165 g _ 88.2 /0 o~ the
theoretical yield of a yellow-orange, water soluble oil;
3o ~ 1.4880.
Analysis calculated ~or C16I-I~4N604, molecular weight 374:
calculated C: 51.~4 o~b; H: 9.09 7h; N: 22.46 %; 0: 17.11 %
observed C: 51.5 ~O ; H: 9.~ //o; N: 22.8 %; 0: 17.4 %~
~:~ 3~93~
EXPMPLE 2:
Azo-di-isobutyric acid-(N,N',N'-tris-2-hydroxyethyl)-amidine (two stage process):
8.8 g (0.2 mole) of ethylene oxide were introduced while cooling with
ice/water at 20 to 30 & into 37.4 g (0.1 mole) of the azo-di-isobutyric acid-
(N,N'-bis-hydroxyethyl)-amidine obtained in accordance with F~ample 1. The mix-
ture was then stirred for 5 hours at rocm temperature (approximately 25C). A
yellow, viscous, water-soluble oil (n20 1.4910) was obtained in a yield of 46 g
or 99 % of the theoretical.
Analysis calculated for C20H42N606, molecular weight 462;
calculated C: 51.95 %; H: 9.09 %; N: 18.18 %; O: 20.78 %
abserved C: 52.2 % ; H: 9.2 % ; N: 18.5 % ; O: 20.4 %O
The same azo-di-isobutyric acid-(N,N',N'-tris-2-hydroxyethyl)-amidine
is also obtained by the following process according to Exa~ple 3:
EX~MPLE 3:
Azo-di-isobutyric acid-(N,N',N'-tris-2-hydroxyethyl)-amidine (one-stage process):
45.6 g (0.2 mole) of azo-di-isobutyric acid im m oethyl ether, 200 ml of
methanol, 42 g (0.4 mole) of diethanolamine and 26 g (0.4 mole) of ethanolamine
were stirred for 8 hours at 50C. To remDve methanol and am~nia (0.4 mole),
the mixture was distilled out m vacuo (12 mbar) at temperatures of up to at
most 50C, leaving 91 g = 98 % of the theoretical yield of a yellow, viscous,
water-soluble oil which had the same refractive index as the oil of the preced-
ing Example and was identical therewith.
EXPMPLE 4:
Azo-di-isobutyric acid-(N,N'-bis-2-hydrcxypropyl)-amidine:
57 g (0.25 mole) of azo-di-isobutyric acid iminomethyl ether, 200 ml
of methanol and 75 g (1 mole) of 1-amino-2-propanol were heated for B ho~lrs to
50C in a water bath, 0.5 mole of ammonia being released. The mixture was dis-
- 21 -
:
~3~3~
tilled at 50 &, first under a pressure of 12 mbar and then under a pressure of
0.1 mbar, in order to re~ve the volatile fractions. A yellcwish wa~er-soluble
oil (nD: 1.4691) was left behind as a residue in a quanti-ty of 93 g, corres-
ponding to a yield of 87 ~ of the theoretical.
Analysis calcuLated for C20H42N604, mDlecular weight 430:
calcula~ed C: 55.81 %; H: 9.76 %; N: 19.53 %; O: 14.88 %
observed C: 56.1 ~ ; H: 10.0 %; N: 19.7 ~ ; O: 14.7 ~.
If the l-amuno-2-propanol in the above nlxture is replaced by l-amino-
3-propanol, azo-di-isobutyric acid-(N,N'-bis-3-hydroxypropyl)-amidine is ob-
tained in the form of a yellow oil which, on standLng, solidifies into ayellowish paste.
EXAMPLE 5:
Aæo-di-isobutyric acid-(N,N'-bis-3-hydroxybutyl)-amidine:
45.6 g (0.2 mole) of azo-di-isobutyric acld imunome~hyl ether, 200 ml
of methanol and 73.2 g (0.8 mole) of 1-amino-3-~utanol were heated for 8 ho~lrs
to 40&, 0.4 mole of ammonia being released. The mixture was distilled at 50&,
first under a pressure of 12 mbar and then under a pressure of 0.1 mbar, to re-
move the volatile fractions. A yellow oil (nD: 1.4801) was left behind as a
residue in a quantit~ of 91 g, corresponding to a yield of 93 % of the
theoretical.
Analysis calculated for C24H50N60~, m~lecular weight 486:
calculated C: 59.26 %; H: 10.29 %; N: 17.28 %; O: 13.13 %
observed C: 59.1 % ; H: 10.5 % ; N: 17.4 % ; O: 13.6 %.
~XPMPLE 6:
A2o-di-isobutyric acid-(N-2-hydroxypropyl-N',N'-bis-2-h~droxyethyl)-amidine:
- 22 -
~3 3a~
~ 23 ~
128 g (0.5 mole) of azo-di-isobutyric acid iminoethyl
ester, 400 ml o~ methanol, 75 g (1 mole) o~ 1-amino-2-
propanol and 105 g (1 mole) of bis-~2-hydro~yethyl)- -~
amine were heated for 8 hours to 503C, 1 mole of ammonia
being releasedO The mi~ture was distilled, ~irst at
. .
50C/12 mbar and then at 50C/0.1 mbar, to remove the
volatile constituents. A yellow water-soluhle oil
( ~ : 1.4780) was left behind as a residue in a quantity
o~ 224 g, corresponding to 92 % of the theoretical yield.
1~ Analysis calculated ~or C22~6N606, molecular weight 490:
calcula-ted C: 5~.88 /0; H: 9.39 %; N: 17 14 %; 0: 19.59 % ~~
observed C: 53.6 % ; H: 9.7 % ; N: 17.0 ~ ; 0: 19.8 /0.
APplicat-i-o-n ~ les ~ to 19 relatin~ to he production
of aqueous poly~ ersions
15 E~AMPLE ?
The emulsion polymerisation reaction is carried out
in a 4-litre 5-necked flask of Jena glass equipped with
a Dimroth re~lu~ condenser, a gas-bubble counter (with
a three-way cock between condenser and sealing ~luid),
a water-cooled stirrer (with a drive motor and centri-
fugally spreading blade~ at 90~ intervals apart) provided
with a nitrogen inlet cock and a ground thermometer or
thermosensor cartridge inserted into the ~lask.
Two Ansch~tz heads are fit-ted to the two remainlng
ground necks, either carrying four dropping funnels with
pressure equalisation ~or the introduction of Solutions
I to IV specified hereinafter or having one dropping
funnel for Solution I and three feed spouts (consisting
of a ground cap and core and of a glass dropping tube
which is centrally ~used in, being bent downwards at
its upper end and provided with a cock) The hoses
leading via three miniature metering pumps to the
supply vessels ~or solutions or mi~tures II, III and IV
are -then optionally connected to these closeable feed
Spouts.
Le A 19 058
~ 313~3~
- 24 -
~ he ~olution of initial reaction mi~ture is then
introduced into the ~lask. After the ~lask has been
evacuated through the three-way cock (with the cocks --~-
of the ~eed spouts and the nitrogen feedpipe closed)~
nitrogen is introduced for equalisation. A T-tube with _~
a non-return valve incorporated in the nitrogen feed
- pipe and dipping into water prevents excess pressure from
builcling up in the glass flask~
Evacuation and gassing with nitrogen are carried
1~ out t;hree -times9 after which all the air has been
dispIaced from the reac~ on zone. The initial reaction
mi~tl:lre is then heated with stirring (appro~imately 250
to 300 rpm) to the required pol~erisation -temperature
(70C') under a slight nitrogen eYcess pressure ~two bubbles
-J5 per seco~d).
To this end, the flask is immersed in a thoroughly
insulated waterbath with an overflow which can be heated
by an immersion heater and cooled through a valve, which
allows ¢old water to flow i~, the m~imum heating rate
and ma~imum cooling rate substantially corresponding to
one ~nother.
The immersion heater and cooler are manipulated
vari~bles of a control system of which the controlled
vari~ble i5 the internal temperature (i.e. the
temperature of the dispersion) and o~ which the disturbance
variable is primarily the exothermic reaction.
In this way, the internal temperature can be very
accurately adjusted~ The deviation from the required
temperature is less -than 1 given a uniform reaction.
3~ Once the required polymerisation temperature has
been reached, Solution I is added all at once, after
which polymerisation generally begins immediately. When
a blueish seed late~ has formed and when the heat of
polymerisation has abated, Solutions II, III, IV are added
Le A 19 058
__
~. 3~
- 25 -
dropwise over a certain period, in this case 6 hours, or
are pumped in through suitable miniature metering pumps
which is more accurate.
A~ter all the components have been added, the
polymerisætion mixture is a~ter-polymerised ~or a
certain time iin thi~l case 2 howrs) at a certai~
temperature ~in thi~ case 85C) in order to complete
con~ersior! o-. the monomers~
gparts by weight,
based on total
components
Initial re~lction mi~',;ure: ~ ~~~
Fully d2saI-I,e~ or dic;tilled
water 93. 33.646
Sodium laur~]. ~ulpha1;e 6.0 0.217
Acrylic ac.id-~-butyl ester 64.2 2.323 --~
Acryloni1r,.1a 17.05 0.617
Styrene 17.05 0.617
Methacryl~m:!.^le 4.0 0. 11L4
S0lution I
Distill.ed wat,er ~or 1.~ully
desalt,ed l~3.ter) 81.0 2.930
Azo~di-iso~utyric ac:i.d-~N,N'-
bis-2~hydx~xyethyl)-amidine 2.5 0,090
Methacrylic acid~ 50~, in water 2.2 0~077
Solution J.l
Acrylic acid~n-butyl ester715.2 25.875
Acrylonitrile 189.9 6.87
Styrene 189.9 6.87
Methacrylamide 45.7 1~6533
~,~
g parts by weigh-t,
based on total
ccmponents
Solution III
Water ~see above) 270.0 9.768
A~o-di-isobutyric acid-(N,N'-
bis-2-hydroxyethyl)-amidine 7.0 0.253
Methacrylic acid, 50 % in
water 6.2 0.224
. .
Solution IV
Water (see above) 196.0 7.091
Sodium lauryl sulphate 20.2 0.731
Sum total 2,764.1 100
Polymerisation temperature: 70C
Addition time for II, III, IV: 6 hours
After-polymerisation: 2 hours at 85 &.
The thinly liquid latex obtained in this way has a solids content of
frcm 45 to 46 ~ and passes freely through a 30 ll square-mesh Perlon cloth, only
a little coarse-grained coagulate ~approximately 0.5 to 5 g) being retained.
The latex has uniform particles approximately 130 nm in diameter. It
dries at 25C to form a clear, non-tacky, highly water-resistant film.
A drop of water left on the surface of the film or about 30 minutes
d oe s not cloud or dissolve the film. In order to improve its ion resistance,
the latex may be aftertreated with non-ionic emulsifiers. However, this is only
necessary for special applications.
The latex may be mixed with standard commercially available water-
soluble melamine~formaldehyde resins or urea-formaldehyde resins of the type
used for stoving lacquers. In addition, pigments and fillers ~ay be added to
these mixtures. Because of the absence of the inorganic solv~rts normally used~
- 26 -
, ~
a~ueous stoving systems of the type in question show improved resistance to
water and adhesion to various substrates, particularly metals.
The polymr on which the latex is based is gel-free, soluble in tetra-
hydrofuran or dimethyl fornE~nide and has an intrinsic viscosity [n] Of 3.0 dl/g
at 25C in tetrahydrofuran.
It consists of:
62.7 % of polymerised butylacrylate units
16.65 % of acrylonitrile units
16.65 % of styrene units
4.0 % methacrylamide units.
EXAMPLE 8 (Ccmparison)
. . _.
A) The procedure is as in Example 7, except that the initiator i5 re-
plaoe d by the same quantity of ammonium peroxy disulphate. me coagulate-free
latex formed is yellow in colour. Clear films of this latex show poorer adhe-
sion to glass and are mDre sensitive to water. Ln analagous co~bination with
pigments, melamine-formaldehyde resin mixtures prepared with this latex give
distinctly poorer results on storage in water. The layers stoved onto metal
separate from the substrate.
B) The procedure is as in Example 7, except tha-t the initiator is re-
placed by the same quan-tity of y,y'-azo-(~-cyano)-valeric acid (formula VI) dis-
solved in an equivalent quantity of dilute aqueous 10 ~ ammonia solution. The
latex has a particle size of approximately 150 nm, is distinctly yellow in
colour and contains approximately 15 g of coagulate. ~he clear film dried at
25 &, to whose surface a drop of water was applied with a pipette, clouds and
dissolves after a~out 30 minutes.
EX~MP _
~he procedure is as in Example 7, except that the initiator is re-
- 27 -
~3,;r
~f~,,
placed by azo-di-isobutyric acid-(N,N',N'-tris-2-hydroxye~hyl)-amidine. A sub-
stantially mono- disperse latex havlng similar properties to the latex described
in Example 7 is obtained.
EX~MPLE 10
m e solution described below as initial reaction mixture is introduced
into the apparatus described in Example 7 and heated under nitnogen to 75 C.
After Solution I has been injected, Solutions II, III and IV æe introduced over
a period of 5 hours, after which the temperature is increased to 80C, followed
by stirring for 2 hours.
A thinly liquid, coagulate-free latex having a solids content of 46.5
is obtained. After the residual monomers have been removed, the la-tex may be
mixed with commercially available water-soluble urea-forn~ildehyde resins or
melamine-formaldehyde resins and pigments and used as an aqueo~ls stoving lacquer.
g parts by weight,
based on total
ccmponents
Initial reaction mlxture:
Distilled water 919.0 31.8971
Sodium lauryl sulphate 6.0 0.208
Acrylic acid-n-butyl ester 60.0 2~082
Acrylonitrile 15.0 0.5205
Styrene 15.0 0.5205
Methacrylic acid-2-hydroxy-
propyl ester 10.0 0.347
Methacrylamide 2.0 0.0694
Methacrylic acid 2.0 0.0694
- 28 -
```~;
..
- 29 -
g parts by weight,
based on total
components -- _
Solution I
Distilled water 100.0 3.471
Azo-di-isobutyric acid-
~N,N'-bis-2-hydroxyethyl)- -.
amidine - 3.0 0.104
Methacrylic acid, 50 % in
10 water 2.64 0~0916
Solution II ..
Acrylic acid-n-butyl ester7G0.0 24.296
Acrylonitrile 175.0 6.074
Styrene 175.0 6.074
15 Methacrylic acid-2- .
hydroxy-propyl ester 116.7 4.050
Methacrylamide 23.3 0.809
Methacrylic acid 23.3 0.809
. . _ . ~
Solution III
20 Distilled water 3oo,o 10.412
Azo-di-isobutyric acid-
(N,N'-bis-2-hydroxy-
ethyl)-amidine 7.0 0.243
Methacrylic acid, 50 % in
water 6.2 0.215
Solution IV
Distilled water 200.0 6.941
Sodium lauryl sulphate 20.0 0.694
. _ ,. . .
Sum total 2,881.14 100
Polymerisation temp~raturs: 75C
Addition time ~or II, IIIf IV: 5 hours
A~ter-polymerisation: 2 hours at 80C.
Lç A 19 058
~ .
- 30 -
Since the monomers are copolymerised subst~ntially
quantitatively, as in the ~ollowing Examples, the
integral composition o~ the polymer corresponds to the
eomposition of the monomer mi~ture:
~7.7 % by weight of butyl acrylate units
14. ~5% by weight o~ acrylonitrile units
l~t.45% by weight of styrene units
9 . 6 /a by weight of methacrylic acid-2-hydroxypropyl
ester units
l.9 /~ by weight of methacrylic acid units
1.9 ~ by weight of methacrylamide units ~~-
lO0 /~ by weight.
XAMPLE 11
O0 parts by weight of distilled water, l part by
weight of an alkyl monosulphonate containing from 12 to
lLt carbon atoms and 0.25 part by weight of azo-di-
isobutyric acid-(N,NI-bis-2-hydroxyethyl)-amidine
are introduced into a three-neckedflask and heated to
~OC .
50 parts by wei~ht of a mix-ture of 200 parts by
weight of styrene, 275 parts by weight of acrylic acid-
n-butyl ester ~nd 25 part~lby weight of methacrylic
acid ~re then added. After stirring for 30 minutes
at 80C, the rest of the monomer mixture ~nd a solution
of 350 parts by weight o~ distilled water~ lO parts by
weight o~ an alkyl monosulphonate containing from 12 to
14 carbon atoms and 5 parts by weight of azo-di-iso-
butyric acid-(N,N'-bis-hydro~yethyl~-amidine are
uniformly added dropwise over a period of 3 hours at
a temperature of 80C, followed by stirring for 2 hours
at 80~C. 1230 parts by weight of a coagulate-free
dispersion are obtained after degassing. The dispersion
has a solids content of 39 % and a mean particle size o~
145 nm. The flowout time from a DIN cup (2 mm ori~ice)
amounts to 69 seconds.
Le A 19 058
~ _ .
EXAMPLE 12
The procedure is as in Example 11, except that the monomer mux-ture
used in that Example is replaced by a mixture of ]90 parts by weight of styrene,
260 parts by weight of acrylic acid-_-butyl ester, 25 parts by weight of meth-
acrylic acid and 25 parts by weight of 2-hydro~ypropyl methacrylate. ~therwise
the conditions are the same. 1150 parts by weight of a coagulate-free disper-
sion are obtained after degassing. The dispersion has a solids content of
39.5 % and a mean particle size of 138 nm. The flcwout time from a M N cup
(2 mm orifice) amounts to 78 seconds.
The dispersion thus obtained dries at 25C to form clear water-
resistant films. It may be mLxed with melamine-form~ldehyde resins or urea-
formaldehyde resins and pigments. m e resulting m~xtures may be stoved onto
metals, forming firmly adhering, water-resistant and solvent-resistant coatings.
EX~MPLE 13
m e procedure is the same as in EXample 12, except that an equivalent
quantity of azo-di-isobutyric acid-(N,N'-bis-2-hydroxypropyl)-amidine is used as
initiator. 1190 parts by weight of a coagulate-free dispersion are obtained
after degassing. The dispersion has a solids content of 37.5 ~, a mean particle
size of 132 nm and a flow-out time from a M N cup (2 mm orifioe) of 75 seconds.
EXAMPLE 14
Polyvinyl chloride l~tex
3000 parts by weight of distilled water, 7.5 parts by weight of an
alkyl monosulphonate containing from 12 to 14 carbon atams, 6 parts by weight of
azo-di-isobutyric acid-(N,N',N'-tris-2-hydroxyethyl)-amidine and 10 parts by
weight of acetic acid are introduced into a stainless-steel autoclave equipped
with an anchor stirrer. me autoclave is evacuated, purged twice with nitro~en
(3 bars) and then evacuated again. 1500 parts by weig~t of vinyl chloride are
then int~odued into the autoclave and the internal temperature is increased to
65 &. I'his temperature is maintained for 12 hours. The initial pressure
amounts to 13 bars. On completion of polymerisation, th2 press~re amounts to 4
bars~
4175 parts by weight of a coagulate~free latex having a particle size
of 180 nm are obtained after degassing. The polymer has an intrinsic viscosity
of 0.77 (as measured in tetrahydrofuran). The solids content amounts to 29 %
and the flowout ti~le frcm a DIN cup (2 mm orifice) to 75 seconds.
EX~MPLE 1
Polyvinyl a oe tate latex
A solution of 12.8 parts by weight of polyvinyl alcohol (partially
hydrolysed polyvlnyl aoe tate with a degree of hydrolysis of 88 %) in 125 parts
by weight of distilled water is prepared in a three-necked flask.
1. A solution of Q.35 part by weight of azo-di-isobutyric acid-(N,N'-
bis-2-hydroxyethyl)-amidine in 40 parts by weight of distilled wa-ter and 0.8
part by weight of aoe tic acid, and
2. 191 parts by weight of vinyl acetate are sim~ltaneously added drop-
wise to the solution heated to 68 C over a period of 3.5 hours, during which thetemperature is kept constant at 68 &. After stirring for another 3.5 hours at
68C, a solution of 0.005 part by weight of azo-di-isobutyric acid~(N,N'-bis-2-
hydroxyethyl)-amidine in 10 parts by weigh-t of distilled water is added dropwise
over a period of 15 minutes, followed by stirring for 45 minutes at 90 C.
350 parts by weight of a highly viscous dispersion having a solids con-
tent of 51 % and a mean particle size of 260 nm are obtained after degassing.
EXAMPLE 16
The prooedure is as in Example 15, except that an e~uivalent quantity
of azo-di-isobutyric acid-(N,N',N'-tris-2-hydroxyethyl)-amidine is used as
initiator.
342 parts ~y weight of a highly viscous dispersion having a solids con-
tent of 48 % and a particle size of 245 nm are obtained.
ExAMæLE 17
Polychloroprene latex
120 parts by weigh~ of distilled water, 5 p~rts by weight of the
sodium salt of a disproportionated abietic acid and 0.6 part by weight of sodium
hydroxide are inltially introduced into a three-necked flask. After purging
with nitrogen for 30 minutes at room temperature, 100 parts by weight of a
chloroprene stabilised with 180 ppm of phenothiazine are stirred in. m e con-
tents of the flask are then heated under nitrogen to 64C, followed by -the drop-
wise addition over a period of 2 hours of a solution of 2.5 parts by weight of
azo-di-isobutyric acid-(N,N'-bis-2-hydroxyethyl)-amidine in 100 parts by weight
of distilled water. The mixture is then stirred for 3 hours at 64C. The
unreacted chloroprene is removed by distillation with steam.
310 parts by weight of a stable dispersion having a solids content of
25.5 % and a mean particle size of 185 nm are obtained.
EXPMPLE 18
The procedure is as in Example 17, except that an equivalent quantity
of azo-di-isobutyric acid-(N,N',N'-tris-2-hydroxyethyl)-amidine is used as
initia~or.
Removal of the unreacted chloroprene by distillation with steam leaves
290 parts by weight of a coagulate-
. ~
l~
0~
- 3~ -
~ree dispersion haviug a solids content o~ 27 /0 and
mean particle size of 170 nm.
EXAMPLE 19
2700 parts by weight of distilled water, 70 parts - :
by weight o~ the sodiwm salt~of a disproportio~ated ~~~
abietic a~id, 7.5 parts by weight of n-dodecyl mercaptan
and 6 parts by weight o~ azo-di-isobutyric a¢id-(N,N'-
bis-2-hydroxyethyl)-~midine are initially introcluced
into a stainless-steel autoclave equipped with an
anchor stirrer. ~he autoclave is evacuated, purged --
twice with nitrogen (3 bars) and then evacuated again.
435 parts by weight of styrene and 1065 parts by weight
of butadiene are then successively pumped in. With the
stirrer rotating at 150 rpm, the contents of the auto~
clave are heated to 65C, the pressure amounting -to 10.5
bars, and kept at this temperature for 10 hours. ~he
pressure then amounts to 8.0 bars. On completion of the
reaction, a solution of 1 part by weight of hydroquinone
in 50 parts by weight of distilled water is introcluced
under pressure for stabilisation.
3450 parts by weight of a coagulate-free late~
are obtained after degassing. The late~ has a solids
con-tent o~ 33 %, a mean par-ticle si~e of 190 nm and a
flow-out time from a DIN cup (2mm orifice) of 130
seconds.
~ulk and Solution Polymerisation ~xamples 20 to 26)
EXAMPLE 20
In a glass bomb tube, a solution of o.6 part by
3o weight of azo-di-isobutyric acid-(N,N'~N'-tris 2-
hydro~yethyl)-amidine in 30 parts by weight of
styrene is gassed with nitrogen for 3 minutes to remove ~~
the air present. After the bomb tube has been sealed
by fusing, its contents are heated for 8 hour~ to 75C.
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~.~3~
The polymerised contents are dissolved in 300 parts
by weight o~ te-trahydrofuran and subsequently precipitated
with 10 times the quantity by weight of methanol. 17
parts by weight of a purified polymer are obtained
5 after drying in YaCuo at 50C. ~_~
Intrinsic viscosity ~as measured in tetrahydrofuran): 0.49.
The polymers may be crosslinked with diisocyanates
and polyisocyanates through the terminal hydro~yl group3
incorporated.
2 parts by weight of the polystyrene containing
terminal hydro~yl groups obtained in accordance with
E~ample 20 are dissolved in 18 parts by weight of
anhydrous chlorobenzene. The solution is crosslinked
with 0.2 part by weight of he~a~ethylene diisocyanate
in the presence of 0.05 part by weight of tin(II) octoate.
After standing for 24 hours at room temperature,
a crosslinked gel has formed. A film cast onto glass
immediately after mixing is also crossli~ked after
drying for 24 hours.
E ~MPLE 21
A solution of o.6 p~rt by weight of azo-di-iso-
butyric acid-(N,N',N'-tris-2-hydroYyethyl)-amidine in
30 parts by weight of methyl me-thacrylate is polymerised
in the same way as described in Example 20. After
dissolution and reprecipitation, 19 g of a polymer having
an intrinsic ~iscosity in tetrahydrofuran of 0.45 are
obtained.
EXAMPLE 22
A solution of 30 parts by weight of acrylonitrile,
3o 70 parts by weight of dimethyl fo~amide and 0.3 part
by weight of azo-di-isobutyric acid-(N,N'-bis-2-
hydro.Yyethyl)-amidine is stirred for 6 hours at 80C
in a three--necked flask equipped with a thermometer,
reflu~ condenser and nitrogen feedpipe. The highly
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~3~
36 -
~iscous solution formed is precipitated in 1000 parts
by weight o~ water and dried in vacuo at 50C.
15 parts o~ a polymer having an intrinsic viscosi-ty ~~:.-
~s measured in dimethyl formamide) of 0.58 are obtained.
E~AMP~E~
___
Following the procedure of Example 22, a solution
~i 30..parts by weight o~ vinyl acetate, 70 parts by
weight of tert.-butanol, 0.3 part by weight o~ azo-di~
-isobutyric acid-(N,N7-bis-~-hydroxyethyl)-amidine and
parts by weight of acetic acid is stirred for 6 hours
at 80C. After th~ highly viscous solution ha~ been
~recipitated in 1000 parts by weight of water, 13 parts
by weight of a polymer having an intrinsic viscosity
~s measured in dimethyl formamide) of 0.35 are obtained
af-ter drying.
~AMPLE 24
500 parts by weight of distilled water are
i.ltroduced into a three-necked fla~kO The content~ of
the flask are then heated under nitrogen to an internal
~s) tempera.ture of 70C, after which
a) lU0 parts by weight of acrylonitrile, and
b3 a solution o~ 0.5 part by weight of azo-di-
isobutyric acid-(N,N'-bis-2-hydro~yethyl)-amidine
in 50 parts by weight of distilled water
are uni~ormly added dropwise over a period of 2 hours.
0~ completion of the dropwise addition, the mixture is
stirred for 2 hours at 70C. The polyacrylonitrile
precipitated is filtered off under suction, washed
thoroughly with water and dried at 50Co
75 parts by weight of a pol~mer are obtained
E.XAMPLE 25
.
o.6 part by weight of azo-di-isobutyric acid-
(N~N'-bis-2-hydroxypropyl)-amidine is used as an
- initiator under the same test conditions as in E~ample
2l~.
Le A 19 058
62 parts by weight of a polymer are obtained.
EXAMPLE 26
_
Following the procedure of Example 20, a mixture of 22.5 parts of
styrene and 7.5 parts of acrylonitrile is polymerised in the presence of 0.15
part o azo-di-isobutyric acid-(N,N'-bis-2-hydroxyethyl)-amidine. Instead of
tetrahydrofuran, dimethyl formamide is used as a solvent for the copolymer.
Drying _ vacuo leaves 19 parts o a purified copolymer consisting of 72 % of
styrene units and 28 % of acrylonitrile units and hav m g an intrinsic viscosityof 0.86, as measured in dLmethyl formamide.
EX~MPLE 27
A mixture of 45 parts of styrene and 55 parts of _-butyl acrylate,
400 parts of chlorobenzene and 2 parts of azo-di-isobutyric acid-(N,N'-bis-3-
hydroxybutyl~-amidine are polymerised in the same way as in Example 22, but for
6 hours at 75 &. me copolymer ormed is precipitated from its chlorobenzene
solu-tion with 1500 parts of methanol and dried Ln vacuo at 50C. 65 parts of a
copolymer of 49 % of styrene units and 51 % of n-b~ltyl acrylate units with an
intrinsic viscosity of 0.72, as measured in di~ethyl formamide, are obtained.
Crosslinking of the copolymer through the OH-groups incorporated
2 parts of the copolymer dissolved in 8 parts of anhydrous chloro-
benzene are mixed with 0.05 part of tin (II) octoate and 0.2 part of isophorone
diisocyanate. Films cast onto gLass frcm this solution are crosslinked after 24
hours at room temperature and can no longer be dissolved by chlorobenzene.
.
