An azo di-isobutyric acid-(N,N'-hydroxyalkyl)-amidine corresponding to the formula (I): ##STR1## in which R and R', which may be the same or different, represent linear or branched alkylene radicals containing from 2 to 4 carbon atoms, and PA1 X represents R'-OH or H. They may be produced by reacting an azo-di-isobutyric acid iminoalkyl ether containing from 1 to 4 carbon atoms in the alkyl group with at least one mono-alkanolamine containing from 2 to 4 carbon atoms or with a mixture of at least one monoalkanolamine and at least one dialkanolamine each containing from 2 to 4 carbon atoms in an alkanol radical, the molar ratio of monoalkanolamines to dialkanolamines in the mixture amounting to substantially 1:1, in substantially equivalent quantitative ratios at a temperature in the range of from 0.degree. to 50.degree. C. The amidines may be used as polymerization initiators, as cross-linking agents and as blowing agents in the production of foams.

This invention relates to new azo-di-isobutyric 
acid-(N,N'-hydroxyalkyl)-amidines and to their use as polymerisation 
initiators, as crosslinking agents and as blowing agents in the production 
of foams. 
U.S. Pat. No. 2,599,299 describes a process for producing the 
dihydrochloride 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, 
however, special precautions have to be taken to ensure that the 
water-moist product does not decompose. 
The use of these compounds as polymerisation initiators has also been 
described (cf. U.S. Pat. No. 2,599,300). 
However, these compounds have never been adopted for use on a commercial 
scale both on account of the instability of the initiators themselves and 
on account 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 salt 
groups: 
##STR2## 
R=residue of the initiator molecule. 
Whereas the solubility of the above-mentioned radical formers in water is 
basically a highly desirable property for polymerisation in aqueous 
suspensions or emulsions, the appearance of salts frequently interferes 
with the polymerisation reaction. In the case of sensitive emulsions, this 
can give rise to premature undesirable coagulation of the emulsions. 
Furthermore, the incorporation of salt-like groups in the polymer formed 
also causes problems in many cases and can have an extremely adverse 
effect upon the properties of the polymer. 
It has now surprisingly been found that the disadvantages referred to above 
can be obviated by using new azo-di-isobutyric 
acid-(N,N'-hydroxyalkyl)-amidines corresponding to the formula (I): 
##STR3## 
in which R and R'--which may be the same or different--represent linear or 
branched alkylene radicals containing from 2 to 4 carbon atoms, and 
X represents hydrogen or --R'--OH, 
as polymerisation initiators. In addition, polymers having very special and 
desirable properties through incorporation of the hydrophilic hydroxyalkyl 
groups are obtained. 
In the formula (I), R and R' preferably represent linear or branched 
alkylene radicals containing 2 or 3 carbon atoms such as --CH.sub.2 
--CH.sub.2 --; --CH.sub.2 --CH.sub.2 --CH.sub.2 -- or 
##STR4## 
and X preferably represents hydrogen or R'--OH. 
R and R' in the formula (I) most preferably are the same and represent a 
linear alkylene radical containing 2 carbon atoms (=ethylene radical) 
whilst X most preferably represents hydrogen or a .beta.-hydroxyethyl 
radical. 
The present invention relates to the azo-di-isobutyric 
acid-(N,N'-hydroxyalkyl)-amidines corresponding to the formula (I) above 
and to their use as radical formers in the polymerisation of unsaturated 
compounds and/or in the crosslinking of polyunsaturated polymerisable 
compounds. 
The azo-di-isobutyric acid-(N,N'-bis-hydroxyalkyl)-amidines and 
azo-di-isobutyric acid-(N,N'-tris-hydroxyalkyl)-amidines according to the 
invention may be produced by 
(A) reacting azo-di-isobutyric acid amidine unsubstituted on the 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 (C.sub.2 
-C.sub.4), or 
(B) reacting azo-di-isobutyric acid iminoalkyl ethers corresponding to the 
general formula (II) below with monoalkanolamines or with mixtures of 
monoalkanolamines and dialkanolamines. 
##STR5## 
In the formula (II), R" represents lower alkyl radicals containing from 1 
to 4 carbon atoms. 
The reaction of azo-di-isobutyric acid iminomethyl ether with 
monoethanolamine [reaction scheme (IIIa)] and the reaction of 
azo-di-isobutyric acid iminoethyl ether with a mixture of mono- and 
di-ethanolamine [reaction scheme (IIIb)] are shown by way of example in 
the following: 
##STR6## 
It is readily possible to produce azo-di-isobutyric acid-(N,N'-bis- or 
N,N'-tris-hydroxyalkyl)-amidines by initially subjecting azo-di-isobutyric 
acid amidine to a partial reaction with an alkylene oxide, followed by 
condensation with mono- and/or di-alkanolamine up to the required degree 
of substitution, or vice versa. On the other hand, the imino groups of the 
azo-di-isobutyric acid iminoalkyl ether may initially be completely or 
partly reacted with an alkylene oxide and the alkyl ether groups and 
residual imino groups, if any, subsequently condensed with mono- and/or 
di-alkanolamine to form the N,N'-bis-(hydroxyalkyl)- or 
N,N',N'-tris(hydroxyalkyl)-amidine of azo-di-isobutyric acid. 
The azo-di-isobutyric acid-(N,N'-bis- or 
N,N',N'-tris-hydroxyalkyl)-amidines are preferably obtained by reacting 
azo-di-isobutyric acid iminoalkyl ether with mono-alkanolamines or with 
mixtures of monoalkanolamines and dialkanolamines (molar ratio 1:1). 
The addition reaction with the alkylene oxides and the condensation 
reaction with mono- and/or di-alkanolamine is carried out at 0.degree. to 
50.degree. C. and preferably at 20.degree. to 45.degree. C. 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, for example in alcohols such as methanol or ethanol; in ethers 
such as diethyl ether or dioxane; 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-epoxy 
butane, 2,3-epoxy butane and 1,2-epoxy-2-methyl propane, preferably 
ethylene oxide and propylene oxide and, more particularly, ethylene oxide. 
The following amines may, e.g., be used for the reaction with the 
iminoalkyl ethers: ethanolamine, diethanolamine, 1-amino-2-propanol, 
bis-(2-hydroxypropyl)-amine, 1-amino-3-propanol, 
bis-(3-hydroxypropyl)-amine, isopropanolamine, diisopropanolamine, 
1-amino-4-butanol, bis-(4-hydroxybutyl)-amine, 1-amino-3-butanol, 
bis-(3-hydroxybutyl)-amine, 1-amino-2-butanol, bis-(2-hydroxybutyl)-amine, 
1-amino-2-methyl-2-propanol, bis-(2-hydroxy-2-methylpropyl)-amine, 
2-amino-2-methyl-1-propanol, bis-(monohydroxy tert.-butyl)-amine, 
1-amino-2-methyl-3-propanol and bis-(3-hydroxy-2-methylpropyl)-amine, or 
mixtures of the above-mentioned amines. 
It is preferred to use ethanolamine, diethanolamine, 1-amino-2-propanol, 
bis-(2-hydroxypropyl)-amine, 1-amino-3-propanol, 
bis-(3-hydroxypropyl)-amine, isopropanolamine, diisopropanolamine or 
mixtures thereof; ethanolamine or diethanolamine or mixtures thereof are 
particularly preferred. 
The alkylene oxides are preferably used in such quantities that 
approximately 1 mole of alkylene oxide is present per imino group of the 
amidines or iminoethers and approximately 2 moles of alkylene oxide per 
amino group of the amidines. The alkanolamines and dialkanolamines are 
preferably used in a quantity of 1 mole per imino, amino or alkylether 
group of the amidines or iminoethers. 
The reaction of iminoalkyl ethers with amines to form amidines is known in 
principle from the literature (cf. Methoden der organischen Chemie, 
Houben-Weyl, 4th Edition (1952), Vol. 8, page 703); as is the 
hydroxyalkylation of amidines with alkylene oxides (cf. U.S. Pat. No. 
2,980,554, column 3, lines 41 to 43). 
The production of the azo-di-isobutyric acid iminoalkyl ethers used as 
starting materials is also known from the literature and may be carried 
out, for example, by the process according to German Offenlegungsschrift 
No. 2,242,520 (pages 31 to 32). 
The following are mentioned as examples of the azo-di-isobutyric 
acid-(N,N'-hydroxyalkyl)-amidines produced 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-hydroxypropyl)-amidine, 
azo-di-isobutyric acid-(N-2-hydroxyethyl-N'-3-hydroxypropyl)-amidine, 
azo-di-isobutyric acid-(N-2-hydroxyethyl-N'-2-hydroxypropyl)-amidine, 
azo-di-isobutyric acid-(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-hydroxyethyl-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-hydroxypropyl-N',N'-bis-2-hydroxyethyl)-amidine. 
The azo-di-isobutyric acid-(N,N'-hydroxyalkyl)-amidines are obtained in a 
smooth high-yield reaction under the above-mentioned reaction conditions 
and are water-soluble, yellow to yellow-orange oils. They may be used as 
radical formers in the polymerisation of unsaturated compounds. They may 
also be used in the crosslinking of, or in crosslinking processes 
involving, unsaturated compounds or products, optionally with foaming. 
They are also suitable for use as blowing agents in the production of 
foams. 
The 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 materials 
or, in combination with pigments and fillers, as coatings for wood, 
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 low as possible. 
The salts not only impair the adhesion of the films to the substrate, but 
they also promote separation of the film from the surface. This is 
particularly critical when the polymer is hard and substantially 
non-tacky. In this case, small quantities of salts have a particularly 
serious affect upon the coalescence of the latex particles. In the 
presence of water, the salts passing into solution build up osmotic 
pressures at the diffusion interfaces of the latex particles which can 
give rise to chalking of the binder and can cause it to soften to the 
point where it dissolves. 
Accordingly, it has been proposed to carry out polymerisation with hydrogen 
peroxide or with water-soluble, non-salt-like derivatives of perhydrol, 
such as tert.-butyl hydroperoxide. However, the latices obtained in this 
way show very poor ion and shear stability. In addition, it has frequently 
been recommended to carry out polymerisation with very small quantities of 
persulphates. Unfortunately, this leads to substantially non-reproducible 
latices, which, in some cases, can completely coagulate. 
It has now been found that polymer dispersions can be obtained without the 
assistance of inorganic salts which adversely affect the adhesion and 
resistance to water of the polymers, providing azo-di-isobutyric 
acid-(N,N'-hydroxyalkyl)-amidines corresponding to the formula (I) above 
are used as polymerisation initiators instead of the usual alkali metal or 
ammonium persulphates or other salt-like peroxy compounds. 
These amidines are a valuble addition to the already known water-soluble 
.alpha.,.alpha.'-azo-(.alpha.-methyl-.gamma.-sulpho)-butyric acid 
dinitrile (IV) (cf. German Auslegesschrift No. 1,111,395), to the 
azodinitriles of the 
.alpha.,.alpha.'-azo-(.alpha.-methyl-.gamma.-diethylamino)-butyric acid 
dinitrile type (V) (cf. U.S. Pat. No. 2,605,260) and of the 
.gamma.,.gamma.'-azo-(.gamma.-cyano)-valeric 
acid=.alpha.,.alpha.'-azo-(.alpha.-methyl-.gamma.-sulpho)-butyric acid 
dinitrile type (VI) (cf. U.S. Pat. No. 2,520,338) or, finally, to the 
2,2'-azo-(2-methylpropionamidine), (VII), (cf. U.S. Pat. Nos. 2,599,299 
and 2,599,300). 
##STR7## 
The amidines corresponding to the formula (VII) are generally used in the 
form of hydrochloric acid salts (cf. U.S. Pat. No. 2,599,300). However, 
they have to be used in ice-cooled form in order to avoid undesirable 
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/1 (1961), pages 222 
et seq.). However, chloride ions are particularly troublesome in a latex 
intended for corrosion prevention, because they accelerate rust formation 
to a considerable extent. In addition, the amidines of the formula (VII) 
can only develop a favourable effect in a neutral or acid mixture. 
By contrast, the initiators according to the invention corresponding to the 
formula (I) above are stable in aqueous 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 mildly 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 for improved adhesion, are 
accessible as reactive groups for crosslinking reactions are are desirable 
for numerous applications. 
Although the compounds corresponding to the formula (IV) give stable 
latices, the sulpho groups which they introdue into the polymer adversely 
affect the resistance to water of the films obtainable from dispersions 
such as these. In addition, the acid groups of the initiators 
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. 
The initiators according to the invention corresponding to the formula (I) 
may be used in alkaline medium and also in acid medium. Even when used in 
small quantities, they lead to high yields of polymer, as can be seen from 
the Examples. 
It has proved to be particularly advantageous to use the initiators 
corresponding to the formula (I) in the form of salts or adducts of 
polymerisable acids. 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 monoolefinically unsaturated carboxylic acids 
containing from 3 to 5 carbon atoms, such as acrylic acid, methacrylic 
acid, crotonic acid, maleic acid and itaconic acid. It is also possible to 
use semiesters of maleic acid, itaconic acid and fumaric acid containing 
from 1 to 18 carbon atoms in the alcohol component. Vinyl sulphonic acid, 
methallyl sulphonic acid or 2-N-acrylamido-2-methyl propane sulphonic acid 
may also be used for adjusting the pH-value in cases where the electrolyte 
stability of the dispersions is of primary importance. 
Finally, the alkaline reaction of the initiators corresponding to the 
formula (I) may also be reduced by additions of alkyl sulphonic acids 
and/or alkylaryl sulphonic acids, in which case salts with emulsifier 
properties are formed. Aliphatic monocarboxylic acids may also be used 
with advantage. 
Polymerisation with the initiators corresponding to the formula (I) is 
preferably carried out at temperatures in the range of from 50.degree. to 
90.degree. C. and, more particularly, at temperatures of from 50.degree. 
to 80.degree. C. and in the absence of applied pressure or under pressures 
of up to 200 bars. 
The initiators may be used in quantities of from 0.2 to 10% by weight, 
based on the monomer total. In general, they are used in quantities of 
from 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 linearly added at a rate which just 
compensates for the decomposition of the initiators at the particular 
polymerisation temperature applied. However, the entire quantity of 
initiator may also be introduced at the outset. Alternatively, most of the 
initiator may be kept for the last fractions of monomer. The products 
obtained differ 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 
production of aqueous stoving lacquers, it is favourable, for example, to 
add most of the OH-group-containing initiators of the formula (I) towards 
the end of the introduction of the monomers so that polymer fractions of 
high molecular weight 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 
with formaldehyde resins are obtained towards the end of polymerisation. 
It has now surprisingly been found that the stability of the polymer 
dispersions produced with the initiators according to the invention is 
extremely good, even when anionic emulsifiers are used, although the 
incorporation of cationic groups into a polymer can generally be expected 
to give rise to flocculations 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 emulsifiers are 
described, for example, in Methoden der Organischen Chemie, Houben-Weyl, 
4th Edition (1961), Vol. XIV/1, pages 190-208 and 4th Edition (1959), Vol. 
II/2, pages 113-138 and in "Surface Active Agents" by A. M. Schwartz and 
J. W. Perry, Interscience Publ. Inc., New York, 1958, pages 25 to 171. 
Combinations of anionic emulsifiers with non-ionic emulsifiers in a ratio 
of from 7:3 to 3:7 (molar ratio) or corresponding combinations of cationic 
emulsifiers with non-ionic emulsifiers are also possible. 
However, polymerisation may also be carried out in the absence of standard 
emulsifiers in cases where compounds which form oligomers with an 
emulsifier-like effect or which perform a dual function of emulsifier and 
monomer are used. 
Compounds 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. However, polymerisation may also be carried 
out in the absence of emulsifiers using protective colloids, such as 
polyvinyl alcohol for example. 
Suitable polymerisable monomers are any olefinically unsaturated monomers 
which can be polymerised in the usual way with azodiisobutyronitrile in 
non-aqueous solution, for example styrene, .alpha.-methyl styrene, 
butadiene, acrylic acid esters containing from 1 to 8 carbon atoms in the 
alcohol component, methacrylic acid esters containing from 1 to 8 carbon 
atoms in the alcohol component, acrylonitrile, methacrylonitrile, vinyl 
chloride, vinylacetate, ethylene, chloroprene, etc. 
In addition to the above-mentioned monomers, water-soluble compounds, such 
as methacrylic acid, acrylic acid, maleic acid semiester, itaconic acid 
and itaconic acid semiester, acrylamide, methacrylamide, etc., may also be 
incorporated 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 as .beta.-hydroxyethyl (meth)acrylate, 
.beta.-hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate and 
N-methylol- or N-methylol-alkyl ethers of (meth)acrylic acid amide. 
The polymer dispersions may be used for a variety of applications. The way 
in which the new initiators act is illustrated in Examples 7 to 19, 
although the potential applications of the polymer dispersions are in no 
way limited by these Examples. 
Where the described dispersions are film-forming, they are eminently 
suitable for coatings, particularly for coatings required 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 melamine-formaldehyde resins or urea-formaldehyde 
resins, or phenoplasts, such as resols. 
In the context of the invention, polymers are understood to be homopolymers 
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 onto a 
preformed homopolymer or copolymer. Of the copolymers, statistical 
copolymers are preferred. 
Azo-di-isobutyric acid-(N,N'-hydroxyalkyl)-amidines corresponding to the 
formula (I) are also eminently suitable for homogeneous-phase 
polymerisation processes known 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 reaction (precipitation polymerisation). 
Virtually any olefinically unsaturated monomers which may be used for 
polymerisation with radical-forming azo compounds are suitable for 
homopolymerisation and copolymerisation in homogeneous phase. The 
following are examples of monomers such as these: 
(a) .alpha.,.beta.-monoolefins containing from 2 to 8 carbon atoms, such as 
ethylene, propylene, 1-butene, isobutylene and diisobutylene; 
(b) conjugated diolefins containing from 4 to 6 carbon atoms, such as 
butadiene, isoprene, 2,3-dimethyl butadiene and 2-chlorobutadiene, 
preferably butadiene; 
(c) (meth)acrylic acid, (meth)acrylonitrile, (meth)acrylamide, alkyl 
(meth)acrylates containing from 1 to 18 and preferably from 1 to 8 carbon 
atoms in the alcohol component, such as methyl acrylate, ethyl acrylate, 
propyl acrylate, isopropyl acrylate, n-butyl acrylate, tert.-butyl 
acrylate, 2-ethylhexyl acrylate, stearyl acrylate and the corresponding 
methacrylic acid alkyl esters, preferably acrylic acid, acrylonitrile, 
acrylamide, methylacrylate, butylacrylate, tert.-butylacrylate, 
2-ethylhexylacrylate, methyl methacrylate; 
(d) vinyl esters of organic monocarboxylic acids, the acid component 
containing from 1 to 18 and preferably from 2 to 4 carbon atoms, such as 
vinyl acetate and vinyl propionate, preferably vinyl acetate; 
(e) monoolefinically unsaturated halogenated hydrocarbons, such as vinyl 
chloride or vinylidene chloride, preferably vinyl chloride; 
(f) aromatic vinyl compounds, such as styrene, o-or p-methyl styrene, 
.alpha.-methyl styrene, .alpha.-methyl-p-isopropyl styrene, 
.alpha.-methyl-m-isopropyl styrene, p-chlorostyrene, preferably styrene. 
In this case, it is preferred always to use the less polymerisable 
monomers, such as .alpha.-methylstyrene and m- or 
p-isopropyl-.alpha.-methyl styrene, in admixture with at least one other 
of the copolymerisable monomers mentioned. 
(g) Monoesters of .alpha.,.beta.-monoolefinically unsaturated 
monocarboxylic acids containing 3 or 4 carbon atoms with dihydric 
saturated aliphatic alcohols containing from 2 to 4 carbon atoms, such as 
2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl 
methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 
4-hydroxybutyl acrylate; 
(h) N-methylol ethers of acrylic and methacrylic acid amide corresponding 
to the general formula (VIII): 
##STR8## 
in which R represents hydrogen or methyl, 
R.sub.1 represents hydrogen, alkyl, aralkyl or aryl, 
R.sub.2 represents alkyl or cycloalkyl, such as methyl, ethyl, n-propyl, 
isopropyl, n-butyl, isobutyl or cyclohexyl (cf. German Auslegeschrift No. 
1,035,363). 
It is preferred to use the N-methylol methylether of methacrylic acid 
amide. The monomers of group (h) are used and incorporated into the 
copolymer in quantities of from 1 to 20% by weight, based on the monomer 
total. 
(i) Diesters and monoesters of .alpha.,.beta.-monoolefinically unsaturated 
C.sub.3 -C.sub.5 -dicarboxylic acids, such as maleic acid, fumaric acid 
and itaconic acid, with 1 to 18 carbon atoms in the alcohol component, and 
also maleic acid anhydride, maleic or fumaric acid, amides of maleic and 
fumaric acid, maleic imides and unsaturated copolymerisable polyesters 
which contain the residues of maleic and/or fumaric acid as polymerisable 
constituents. Maleic acid anhydride is preferred. 
(j) Vinylalkyl ethers containing from 1 to 4 carbon atoms in the alkyl 
group, such as vinylmethyl ether, vinylethyl ether, vinylpropyl ether, 
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 perhydro-S-triazine, 
bis-acrylates and bis-methacrylates of glycols and polyglycols containing 
from 2 to 20 carbon atoms, such as ethylene glycol di(meth)acrylate, 
propylene glycol di(meth)acrylate, butylene glycol-1,4-di(meth)acrylate, 
tetraethylene glycol di(meth)acrylate, and tris-(meth)acrylates of 
trimethylol propane and glycerol. 
The crosslinking monomers of group (k) are preferably used for 
copolymerisation in quantities of from 0.1 to 12% by weight, based on the 
monomer total. They are incorporated into the copolymer in the same 
quantities. 
In addition, primary, secondary or tertiary aminoalkyl esters of 
(meth)acrylic acid preferably containing from 2 to 4 carbon atoms in the 
alkyl group and glycido(meth)acrylate may also be used as comonomers and 
may optionally be crosslinked through the amino or epoxide group during or 
after copolymerisation. 
Monomers of groups (b), (c), (d), (e), (f), and (i) are preferably used for 
copolymerisation. 
Where polymerisation is carried out in solution, water and organic 
solvents, for example dimethyl formamide, tert.-butanol, chlorobenzenes, 
etc., may be used as solvents. 
The polymerisation reaction may be carried out at temperatures of from 
50.degree. C. to 90.degree. C. and preferably at temperatures of from 
55.degree. C. to 75.degree. C., depending on the decomposition 
characteristic of the azo compounds according to the invention. The 
quantity in which the initiator is used may be adapted to the required 
molecular weight and may amount to be between 0.05 and 10% by weight or 
more, based on the monomers used. It is, of course, also possible to 
deviate from these figures on the quantity of initiator and the 
temperature. The polymerisation reactions in homogeneous phase may be 
carried out in the absence of pressure or under pressures of up to 1500 
bars. 
In every case, the polymers obtained contain at least 2 hydroxyl groups, 
emanating from the initiator fragments, incorporated at the beginning and 
end of each polymer chain. 
The introduction of hydroxyl groups at the beginning and end of polymer 
chains is of considerable practical importance to a variety of properties. 
On the one hand, the reactivity of the polymers enables them to be reacted 
with compounds which generally react with hydroxyl groups and form 
wide-mesh networks. Compounds such as these are, for example, 
polyisocyanates, polyepoxides, polycarboxylic acid anhydride, and 
compounds containing methylol and/or methylol ether groups. In addition, 
the hydroxyl groups considerably improve the adhesion of polymer films.

Examples 20 to 27 illustrate bulk and solution polymerisation reactions 
using the azo-di-isobutyric acid-(N,N'-hydroxyalkyl)-amidines 
corresponding to the formula (I). 
The parts and percentages quoted in the Examples are by weight, unless 
otherwise indicated. The intrinsic viscosity [.eta.], [dl/g] was measured 
in the solvents indicated at a temperature of 25.degree. C. 
Production of the azo-di-isobutyric acid-(N,N'-hydroxyalkyl)-amidines 
EXAMPLE 1 
Azo-di-isobutyric acid-(N,N'-bis-2-hydroxyethyl)-amidine 
114 g (0.5 mole) of azo-di-isobutyric acid iminomethyl ether, 300 ml of 
methanol and 122 g (2 moles) of ethanolamine were stirred for 8 hours at 
50.degree. C. To remove methanol and ammonia (1 mole), the mixture was 
distilled out in a water jet vacuum (12 mbar) at temperatures of up to at 
most 50.degree. C., leaving 165 g=88.2% of the theoretical yield of a 
yellow-orange, water-soluble oil; n.sub.D.sup.20 1.4880. 
Analysis calculated for C.sub.16 H.sub.34 N.sub.6 O.sub.4, molecular weight 
374: calculated C: 51.34%; H: 9.09%; N: 22.46%; O: 17.11%. observed C: 
51.5%; H: 9.3%; N: 22.8%; O: 17.4%. 
EXAMPLE 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.degree. to 30.degree. C. into 37.4 g (0.1 mole) of the 
azo-di-isobutyric acid-(N,N'-bishydroxyethyl)-amidine obtained in 
accordance with Example 1. The mixture was then stirred for 5 hours at 
room temperature (approximately 25.degree. C.). A yellow, viscous, 
water-soluble oil (n.sub.D.sup.20 1.4910) was obtained in a yield of 46 g, 
or 99% of the theoretical yield. 
Analysis calculated for C.sub.20 H.sub.42 N.sub.6 O.sub.6, molecular weight 
462: Calculated C: 51.95%; H: 9.09%; N: 18.18%; O: 20.78%. observed C: 
52.2%; H: 9.2%; N: 18.5%; O: 20.4%. 
The same azo-di-isobutyric acid-(N,N',N'-tris-2-hydroxyethyl)-amidine is 
also obtained by the following process according to Example 3: 
EXAMPLE 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 iminoethyl 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 50.degree. C. To remove methanol 
and ammonia (0.4 mole), the mixture was distilled out in vacuo (12 mbar) 
at temperatures of up to at most 50.degree. C., 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 preceding Example and was 
identical therewith. 
EXAMPLE 4 
Azo-di-isobutyric acid-(M,N'-bis-2-hydroxypropyl)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 8 hours 
to 50.degree. C. in a water bath, 0.5 mole of ammonia being released. The 
mixture was distilled at 50.degree. C., first under a pressure of 12 mbar 
and then under a pressure of 0.1 mbar in order to remove the volatile 
fractions. A yellowish water-soluble oil (n.sub.D.sup.20 : 1.4691) was 
left behind as a residue in a quantity of 93 g, corresponding to a yield 
of 87% of the theoretical. 
Analysis calculated for C.sub.20 H.sub.42 N.sub.6 O.sub.4, molecular weight 
430: calculated 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 1-amino-2-propanol in the above mixture is replaced by 
1-amino-3-propanol, azo-di-isobutyric 
acid(N,N'-bis-3-hydroxypropyl)-amidine is obtained in the form of a yellow 
oil which, on standing, solidifes into a yellowish paste. 
EXAMPLE 5 
Azo-di-isobutyric acid-(N,N'-bis-3-hydroxybutyl)-amidine 
45.6 g (0.2 mole) of azo-di-isobutyric acid iminomethyl ether, 200 ml of 
methanol and 73.2 g (0.8 mole) of 1-amino-3-butanol were heated for 8 
hours to 40.degree. C., 0.4 mole of ammonia being released. The mixture 
was distilled at 50.degree. C., first under a pressure of 12 mbar and then 
under a pressure of 0.1 mbar to remove the volatile fractions. A yellow 
oil (n.sub.D.sup.20 :1.4801) was left behind as a residue in a quantity of 
91 g corresponding to a yield of 93% of the theoretical. 
Analysis calculated for C.sub.25 H.sub.50 N.sub.6 O.sub.4, molecular 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%. 
EXAMPLE 6 
Azo-di-isobutyric acid-(N-2-hydroxypropyl-N',N'-bis-2-hydroxyethyl)-amidine 
128 g (0.5 mole) of azo-di-isobutyric acid iminoethyl ester, 400 ml of 
methanol, 75 g (1 mole) of 1-amino-2-propanol and 105 g (1 mole) of 
bis-(2-hydroxyethyl)amine were heated for 8 hours to 50.degree. C., 1 mole 
of ammonia being released. The mixture was distilled, first at 50.degree. 
C./12 mbar and then at 50.degree. C./0.1 mbar to remove the volatile 
constituents. A yellow water-soluble oil (n.sub.D.sup.20 : 1.4780) was 
left behind as a residue in a quantity of 224 g, corresponding to 92% of 
the theoretical. 
Analysis calculated for C.sub.22 H.sub.46 N.sub.6 O.sub.6, molecular weight 
490: calculated C: 53.88%; H: 9.39%; N: 17.14%; O: 19.59%. observed C: 
53.6%; H: 9.7%; N: 17.0%; O:19.8%. 
Application Examples 7 to 19 relating to the production of aqueous polymer 
dispersions 
EXAMPLE 7 
The emulsion polymerisation reaction is carried out in a 4-liter 5-necked 
flask of Jena glass equipped with a Dimroth reflux condenser, a gas-bubble 
counter (with a three-way cock between condenser and sealing fluid), a 
water-cooled stirrer (with a drive motor and centrifugally spreading 
blades at 90.degree. intervals apart) provided with a nitrogen inlet cock 
and a group thermometer or thermosensor cartridge inserted into the flask. 
Two Anschutz heads are fitted to the two remaining ground necks, either 
carrying four dropping funnels with pressure equalisation for 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 of a glass dropping tube which is centrally fused 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 for 
solutions or mixtures II, III and IV are then optionally connected to 
these closeable feed spouts. 
The solution of initial reaction mixture is then introduced into the flask. 
After the flask has been evacuated through the three-way cock (with the 
cocks of the feed 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 building up in the glass flask. 
Evacuation and gassing with nitrogen are carried out three times, after 
which all the air has been displaced from the reaction zone. The initial 
reaction mixture is then heated with stirring (approximately 250 to 300 
rpm) to the required polymerisation temperature (70.degree. C.) under a 
slight nitrogen excess pressure (two bubbles per second). 
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 cold water to flow in, the maximum heating rate and 
maximum cooling rate substantially corresponding to one another. 
The immersion heater and cooler are manipulated variables of a control 
system of which the controlled variable is the internal temperature (i.e. 
the temperature of the dispersion) and of 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.degree., given a 
uniform reaction. 
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 latex has formed and when the heat of 
polymerisation has abated, solutions II, III, IV are added dropwise over a 
certain period, in this case 6 hours, or are pumped in through suitable 
miniature metering pumps which is more accurate. 
After all the components have been added, the polymerisation mixture is 
after-polymerised for a certain time (in this case 2 hours) at a certain 
temperature (in this case 85.degree. C.) in order to complete conversion 
of the monomers. 
______________________________________ 
parts by weight, 
based on total 
g components 
______________________________________ 
Initial reaction mixture: 
Fully desalted or distilled water 
930.0 33.646 
Sodium lauryl sulphate 
6.0 0.217 
Acrylic acid-n-butyl ester 
64.2 2.323 
Acrylonitrile 17.05 0.617 
Styrene 17.05 0.617 
Methacrylamide 4.0 0.144 
Solution I 
Distilled water (or fully 
desalted water) 81.0 2.930 
Azo-di-isobutyric acid-(N,N'- 
bis-2-hydroxyethyl)-amidine 
2.5 0.090 
Methacrylic acid, 50% in water 
2.2 0.077 
Solution II 
Acrylic acid-n-butyl ester 
715.2 25.875 
Acrylonitrile 189.9 6.87 
Styrene 189.9 6.87 
Methacrylamide 45.7 1.6533 
Solution III 
Water (see above) 270.0 9.768 
Azo-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) 195.0 7.091 
Sodium lauryl sulphate 
20.2 0.731 
Sum total 2,764.1 100 
______________________________________ 
Polymerisation temperature: 70.degree.C. 
Addition time for Solutions II, III, IV: 6 hours 
Afterpolymerisation: 2 hours at 85.degree. C. 
The thinly liquid latex obtained in this way has a solids content of from 
45 to 46% and passes freely through a 30.mu. 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 25.degree. C. to form a clear, non-tacky, highly water-resistant film. 
A drop of water left on the surface of the film for about 30 minutes does 
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 may be added to 
these mixtures. Through the absence of the inorganic solvents normally 
used, aqueous stoving systems of the type in question show improved 
resistance to water and adhesion to various substrates, particularly 
metals. 
The polymer on which the latex is based is gel-free, soluble in 
tetrahydrofuran or dimethyl formamide and has an intrinsic viscosity 
[.eta.] of 3.0 dl/g at 25.degree. C. in tetrahydrofuran. 
It consists of: 
62.7% of polymerised butyl acrylate units 
16.65% of acrylonitrile units 
16.65% of styrene units 
4.0% of methacrylamide units. 
EXAMPLE 8 (Comparison) 
(A) The procedure is as in Example 7, except that the initiator is replaced 
by the same quantity of ammonium peroxy disulphate. The coagulate-free 
latex formed is yellow in colour. Clear films of this latex show poorer 
adhesion to glass and are more sensitive to water. In analogous 
combination 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 that the initiator is replaced 
by the same quantity of .gamma.,.gamma.'-azo-(.gamma.-cyano)-valeric acid 
(formula VI) dissolved 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. The clear film dried at 25.degree. C., to whose surface a drop 
of water was applied with a pipette, clouds and dissolves after about 30 
minutes. 
EXAMPLE 9 
The procedure is as in Example 7, except that the initiator is replaced by 
azo-di-isobutyric acid-(N,N',N'-tris-2-hydroxyethyl)-amidine. A 
substantially monodisperse latex having similar properties to the latex 
described in Example 7 is obtained. 
EXAMPLE 10 
The solution described below as initial reaction mixture is introduced into 
the apparatus described in Example 7 and heated under nitrogen to 
75.degree. C. After Solution I has been injected, Solutions II, III and IV 
are introduced over a period of 5 hours, after which the temperature is 
increased to 80.degree. C., 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 latex may be 
mixed with commercially available water-soluble urea-formaldehyde resins 
or melamine-formaldehyde resins and pigments and used as an aqueous 
stoving lacquer. 
______________________________________ 
parts by weight, 
based on total 
g components 
______________________________________ 
Initial reaction mixture: 
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 
Methylacrylamide 2.0 0.0694 
Methacrylic acid 2.0 0.0694 
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 
water 2.64 0.0916 
Solution II 
Acrylic acid-n-butyl ester 
700.0 24.296 
Acrylonitrile 175.0 6.074 
Styrene 175.0 6.074 
Methacrylic acid-2-hydroxy- 
propyl ester 116.7 4.050 
Methacrylamide 23.3 0.809 
Methacrylic acid 23.3 0.809 
Solution II 
Distilled water 300.0 10.412 
Azo-di-isobutyric acid- 
(N,N'-bis-2-hydroxyethyl)- 
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 temperature: 75.degree. C. 
Addition time for Solutions II, III, IV: 5 h 
Afterpolymerisation: 2 hours at 80.degree. C. 
Since the monomers are copolymerised substantially quantitatively, as in 
the following Examples, the integral composition of the polymer 
corresponds to the composition of the monomer mixture: 
______________________________________ 
57.7% by weight of butyl acrylate units 
14.45% by weight of acrylonitrile units 
14.45% by weight of styrene units 
9.6% by weight of methacrylic acid-2-hydroxypropyl 
ester units 
1.9% by weight of methacrylic acid units 
1.9% by weight of methacrylamide units 
100% by weight. 
______________________________________ 
EXAMPLE 11 
400 Parts by weight of distilled water, 1 part by weight of an alkyl 
monosulphonate containing from 12 to 14 carbon atoms and 0.25 part by 
weight of azo-diisobutyric acid-(N,N'-bis-2-hydroxyethyl)-amidine are 
introduced into a three-necked flask and heated to 80.degree. C. 
50 Parts by weight of a mixture of 200 parts by weight of styrene, 275 
parts by weight of acrylic acid-n-butyl ester and 25 parts by weight of 
methacrylic acid are then added. After stirring for 30 minutes at 
80.degree. C., the rest of the monomer mixture and a solution of 350 parts 
by weight of distilled water, 10 parts by weight of an alkyl 
monosulphonate containing from 12 to 14 carbon atoms and 5 parts by weight 
of azo-diisobutyric acid-(N,N'-bis-hydroxyethyl)-amidine are uniformly 
added dropwise over a period of 3 hours at a temperature of 80.degree. C. 
followed by stirring for 2 hours at 80.degree. 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 of 145 nm. The 
flowout time from a DIN cup (2 mm orifice) amounts to 69 seconds. 
EXAMPLE 12 
The procedure is as in Example 11, except that the monomer mixture used in 
that Example is replaced by a mixture of 190 parts by weight of styrene, 
260 parts by weight of acrylic acid-n-butyl ester, 25 parts by weight of 
methacrylic acid and 25 parts by weight of 2-hydroxypropyl methacrylate. 
Otherwise the conditions are the same. 1150 Parts by weight of a 
coagulate-free dispersion are obtained after degassing. The dispersion has 
a solids content of 39.5% and a mean particle size of 138 nm. The flowout 
time from a DIN cup (2 mm orifice) amounts to 78 seconds. 
The dispersion thus obtained dries at 25.degree. C. to form clear 
water-resistant films. It may be mixed with melamine-formaldehyde resins 
or urea-formaldehyde resins and pigments. The resulting mixtures may be 
stoved onto metals, forming firmly adhering, water-resistant and 
solvent-resistant coatings. 
EXAMPLE 13 
The 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 DIN cup (2 mm 
orifice) of 75 seconds. 
EXAMPLE 14 
Polyvinyl chloride latex 
3000 Parts by weight of distilled water, 7.5 parts by weight of an alkyl 
monosulphonate containing from 12 to 14 carbon atoms, 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. The autoclave is evacuated, purged twice 
with nitrogen (3 bars) and then evacuated again. 1500 Parts by weight of 
vinyl chloride are then introduced into the autoclave and the internal 
temperature is increased to 65.degree. C. This temperature is maintained 
for 12 hours. The initial pressure amounts to 13 bars. On completion of 
polymerisation, the pressure 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 time from a DIN cup (2 mm orifice) to 75 
seconds. 
EXAMPLE 15 
Polyvinyl acetate latex 
A solution of 12.8 parts by weight of polyvinyl alcohol (partially 
hydrolysed polyvinyl acetate 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 0.35 part by weight of azo-di-isobutyric 
acid-(N,N'-bis-2-hydroxyethyl)-amidine in 40 parts by weight of distilled 
water and 0.8 part by weight of acetic acid, and 
2. 191 Parts by weight of vinyl acetate, are simultaneously added dropwise 
to the solution heated to 68.degree. C. over a period of 3.5 hours, during 
which the temperature is kept constant at 68.degree. C. After stirring for 
another 3.5 hours at 68.degree. C., a solution of 0.05 part by weight of 
azo-di-isobutyric acid-(N,N'-bis-2-hydroxyethyl)-amidine in 10 parts by 
weight of distilled water is added dropwise over a period of 15 minutes, 
followed by stirring for 45 minutes at 90.degree. C. 
350 Parts by weight of a highly viscous dispersion having a solids content 
of 51% and a mean particle size of 260 nm are obtained after degassing. 
EXAMPLE 16 
The procedure is as in Example 15 except that an equivalent quantity of 
azo-di-isobutyric acid-(N,N',N'-tris-2-hydroxyethyl)-amidine is used as 
initiator. 
342 Parts by weight of a highly viscous dispersion having a solids content 
of 48% and a particle size of 245 nm are obtained. 
EXAMPLE 17 
Polychloroprene latex 
120 Parts by weight of distilled water, 5 parts by weight of the sodium 
salt of a disproportionated abietic acid and 0.6 part by weight of sodium 
hydroxide are initially 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. The contents of the flask are then heated under nitrogen to 
64.degree. C., followed by the dropwise 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 64.degree. C. 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. 
EXAMPLE 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 
initiator. 
Removal of the unreacted chloroprene by distillation with steam leaves 290 
parts by weight of a coagulate-free dispersion having a solids content of 
27% and a mean particle size of 170 nm. 
EXAMPLE 19 
Styrene-butadiene latex 
2700 Parts by weight of distilled water, 70 parts by weight of the sodium 
salt of a disproportionated abietic acid, 7.5 parts by weight of n-dodecyl 
mercaptan and 6 parts by weight of azo-di-isobutyric 
acid-(N,N'-bis-2-hydroxyethyl)-amidine are initially introduced into a 
stainless-steel autoclave equipped with an anchor stirrer. The 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 autoclave are heated to 65.degree. C., the 
pressure amounting to 10.5 bars, and kept at this temperature for 10 
hours. The 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 introduced under pressure for stabilisation. 
3450 Parts by weight of a coagulate-free latex are obtained after 
degassing. The latex has a solids content of 33%, a mean particle size of 
190 nm and a flow-out time from a DIN cup (2 mm orifice) of 130 seconds. 
Bulk and Solution Polymerisation (Examples 20 to 26) 
EXAMPLE 20 
In a glass bomb tube, a solution of 0.6 part by weight of azo-di-isobutyric 
acid-(N,N',N'-tris-2-hydroxyethyl)-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 hours to 75.degree. C. 
The polymerised contents are dissolved in 300 parts by weight of 
tetrahydrofuran and subsequently precipitated with 10 times the quantity 
by weight of methanol. 17 parts by weight of purified polymer are obtained 
after drying in vacuo at 50.degree. C. 
Intrinsic viscosity (as measured in tetrahydrofuran): 0.49. 
The polymers may be crosslinked with diisocyanates and polyisocyanates 
through the terminal hydroxyl groups incorporated. 
2 Parts by weight of the polystyrene containing terminal hydroxyl groups 
obtained in accordance with Example 20 are dissolved in 18 parts by weight 
of anhydrous chlorobenzene. The solution is crosslinked with 0.2 part by 
weight of hexamethylene 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 
crosslinked after drying for 24 hours. 
EXAMPLE 21 
A solution of 0.6 part by weight of azo-di-isobutyric 
acid-(N,N',N'-tris-2-hydroxyethyl)-amidine in 30 parts by weight of methyl 
methacrylate is polymerised in the same way as described in Example 20. 
After dissolution and reprecipitation, 19 g of polymer having an intrinsic 
viscosity in tetrahydrofuran of 0.45 are obtained. 
EXAMPLE 22 
A solution of 30 parts by weight of acrylonitrile, 70 parts by weight of 
dimethyl formamide and 0.3 part by weight of azo-di-isobutyric 
acid-(N,N'-bis-2-hydroxyethyl)-amidine is stirred for 6 hours at 
80.degree. C. in a three-necked flask equipped with a thermometer, reflux 
condenser and nitrogen feedpipe. The highly viscous solution formed is 
precipitated in 1000 parts by weight of water and dried in vacuo at 
50.degree. C. 
15 Parts of a polymer having an intrinsic viscosity (as measured in 
dimethyl formamide) of 0.58 are obtained. 
EXAMPLE 23 
Following the procedure of Example 22, a solution of 30 parts by weight of 
vinyl acetate, 70 parts by weight of tert.-butanol, 0.3 part by weight of 
azo-di-isobutyric acid-(N,N'-bis-2-hydroxyethyl)-amidine and 2 parts by 
weight of acetic acid is stirred for 6 hours at 80.degree. C. After the 
highly viscous solution has been precipitated in 1000 parts by weight of 
water, 13 parts by weight of a polymer having an intrinsic viscosity (as 
measured in dimethyl formamide) of 0.35 are obtained after drying. 
EXAMPLE 24 
500 Parts by weight of distilled water are introduced into a three-necked 
flask. The contents of the flask are then heated under nitrogen to an 
internal temperature of 70.degree. C., after which 
(a) 100 parts by weight of acrylonitrile, and 
(b) a solution of 0.5 part by weight of azo-di-isobutyric 
acid-(N,N'-bis-2-hydroxyethyl)-amidine in 50 parts by weight of distilled 
water, 
are uniformly added dropwise over a period of 2 hours. On completion of the 
dropwise addition, the mixture is stirred for 2 hours at 70.degree. C. The 
polyacrylonitrile precipitated is filtered off under suction, washed 
thoroughly with water and dried at 50.degree. C. 
75 Parts by weight of polymer are obtained. 
EXAMPLE 25 
0.6 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 Example 24. 
62 Parts by weight of 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 
of azo-di-isobutyric acid-(N,N'-bis-2-hydroxyethyl)amidine. Instead of 
tetrahydrofuran, dimethyl formamide is used as solvent for the copolymer. 
Drying in vacuo leaves 19 parts of purified copolymer consisting of 72% of 
styrene units and 28% of acrylonitrile units and having an intrinsic 
viscosity of 0.86, as measured in dimethyl formamide. 
EXAMPLE 27 
A mixture of 45 parts of styrene and 55 parts of n-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.degree. C. The copolymer formed is 
precipitated from its chlorobenzene solution with 1500 parts of methanol 
and dried in vacuo at 50.degree. C. 65 parts of a copolymer having 49% of 
styrene units and 51% of n-butylacrylate units and an intrinsic viscosity 
of 0.72, as measured in dimethyl formamide, are obtained. 
Crosslinking of the copolymer through the OH-groups incorporated 
2 Parts of the copolymer dissolved in 8 parts of anhydrous chlorobenzene 
are mixed with 0.05 part of tin(II) octoate and 0.2 part of isophorone 
diisocyanate. Films cast onto glass from this solution are crosslinked 
after 24 hours at room temperature and can no longer be dissolved by 
chlorobenzene.