Graft polymers

A process for the preparation of graft polymers from ethylene homopolymers or copolymers and olefinically unsaturated monomers, especially from ethylene/vinyl ester copolymers, in the presence of a radical forming agent in homogenous or heterogeneous phase, in which a mixture of (meth)acrylonitrile, at least one aromatic vinyl compound and vinylchloride are polymerized in the presence of an ethylene homopolymer or copolymer. The products obtained contain no ungrafted styrene/acrylonitrile copolymer and more than 80% by weight of the graft polymer is chemically almost uniform in structure. The products obtained according to the invention are eminently suitable for use as coating materials and as materials which can be thermoplastically processed.

This invention relates to graft polymers consisting of ethylene 
homopolymers or copolymers as graft substrate and a mixture of 
(meth)acrylonitrile, aromatic monovinyl compounds and vinyl chloride as 
graft monomers, and to a process for their preparation. 
It is known that radical grafting of mixtures of styrene and acrylonitrile 
on ethylene copolymers leads to inhomogeneous graft products which consist 
of a mixture of graft copolymers, ungrafted graft substrate and free 
styrene/acrylonitrile copolymer as described in British Patent 
Specification No. 917,498 and the article by J. L. Locatelli and G. Riess 
in Angewandte Makromolekulare Chemie 32 (1973), pages 117-129. 
The inhomogeneity of the resulting graft products is particularly 
troublesome in cases where the graft substrate and styrene/acrylonitrile 
copolymers are incompatible with each other. In some cases, the graft 
products obtained have properties which make them unsuitable for 
processing and poor mechanical properties. This applies particularly to 
the system of polyethylene/styrene-acrylonitrile. 
A process for grafting styrene and acrylonitrile in the presence of 
monoolefines such as propylene or isobutylene has been described in German 
Offenlegungsschrift No. 2,215,588. The yield of graft product can be 
dramatically improved by using these olefins as regulators for the 
process, but it is always possible to use up these regulators 
quantitatively during the reaction. 
It was therefore an object of the present invention to find a grafting 
process which would result in chemically and molecularly homogeneous graft 
products and in which the regulator would be virtually completely used up 
by copolymerisation during the reaction. 
This problem can be substantially solved by using 0.01 to 15% by weight, 
preferably 0.1 to 5% by weight, based on the monomer mixture which is 
required to be grafted on the substrate, of vinyl chloride as regulator in 
the grafting reaction. 
The present invention thus relates to a process for the preparation of 
graft polymers from ethylene homopolymers or copolymers and olefinically 
unsaturated monomers in the presence of a radical forming agent in 
homogeneous or heterogeneous phase, in which mixtures of 
(meth)acrylonitrile, at least one aromatic vinyl compound and vinyl 
chloride are polymerised in the presence of ethylene homopolymers or 
copolymers. 
By ethylene homopolymers are meant polyethylenes which are prepared by 
known methods of low, medium or high pressure synthesis, which may vary in 
structure from linear to strongly branched and which have molecular 
weights, as determined by the method of light scattering, of 5000 or more. 
Suitable ethylene copolymers include ethylene/vinyl ester copolymers 
preferably containing 1 to 75 % by weight, in particular 5 to 50 % by 
weight, of vinyl esters built into the copolymers. The vinyl esters may be 
organic vinyl esters of aliphatic saturated monocarboxylic acids 
containing 1 to 18 carbon atoms, which may be halogen substituted, in 
particular chlorine substituted or aromatic monocarboxylic acids 
containing 7 to 11 carbon atoms. The following are specific examples: 
Vinyl formate; vinyl acetate; vinyl propionate; vinyl chloropropionate; 
vinyl butyrate; vinyl isobutyrate; vinyl caproate; vinyl laurate; vinyl 
myristate; vinyl stearate and vinyl benzoate; vinyl acetate is preferred. 
The ethylene/vinyl ester copolymers are prepared by known methods of high 
or medium pressure synthesis, if desired in solvents such as tertiary 
butanol. 
The ethylene/vinyl ester copolymers prepared by the high pressure synthesis 
method have melt index values of from 0.1 to 100, preferably from 1.0 to 
10 and more particularly from 4.5 to 6. The intrinsic viscosities 
determined in tetralin at 120.degree. C are generally from 0.6 to 1.5. The 
molecular weights determined by the method of light scattering are 
preferably from 50,000 to about 1 million. The nonuniformity U defined by 
the term (Mw/Mn) - 1 (G. V. Schulz, in Z. phys. Chem. (B) 43 (1939), pages 
25 to 34) is within the range of from 5 to 20. These copolymers are 
preferably soluble in hot hydrocarbons and may contain up to 40 % by 
weight of vinyl esters. 
The ethylene/vinyl ester copolymers prepared, for example, by the solution 
polymerisation method and containing, for example, 30 to 75 % by weight of 
vinyl acetate, preferably 40 to 55 % by weight of vinyl acetate, have melt 
index values which are in part no longer measurable at 190.degree. C 
according to DIN 53 735 under a loading of 2.16 kp but may also be greater 
than 100. The melt index range is preferably below 15, and in particular 
from 3 to 5. The molecular weights determined by the light scattering 
method are preferably from 40,000 to 500,000. The nonuniformity U is from 
2 to 6. 
The vinyl esters used may be the organic vinyl esters mentioned above. 
The copolymers are soluble in hydrocarbons and those which have higher 
vinyl ester contents are also soluble in alcohols and preferably have 
intrinsic viscosities in toluene at 25.degree. C of from 0.5 to 2.0. 
Suitable ethylene copolymers also include the copolymers of ethylene with 
.alpha.,.beta.-monoolefinically unsaturated carboxylic acids containing 3 
to 5 carbon atoms and their derivatives. These copolymers preferably 
contain from 1 to 80 % by weight, in particular from 1 to 30% by weight, 
of these carboxylic acid derivatives. 
The preferred .alpha.,.beta.-monoolefinically unsaturated carboxylic acids 
with 3 to 5 carbon atoms are (meth)acrylic acid, crotonic acid, fumaric 
acid, maleic acid, and itaconic acid. (Meth)acrylic acid and maleic acid 
are particularly preferred. 
Carboxylic acid derivatives of the above mentioned acids may also be used, 
in particular their monoesters of diesters with 1 to 8 carbon atoms in the 
alcohol component or their anhydrides. 
The graft substrates which yield the best results are ethylene homopolymers 
and ethylene/vinyl ester copolymers, in particular ethylene/vinyl acetate 
copolymers. 
The ethylene/vinyl ester copolymers may be partly or completely hydrolysed 
if desired. 
The monomers which may be grafted on the substrates include 
methacrylonitrile and/or acrylonitrile, aromatic monovinyl compounds such 
as styrene, nuclear substituted alkyl styrenes containing 1 to 5 carbon 
atoms in the alkyl group, e.g. 4-methylstyrene, .alpha.-methylstyrene, 
halogenated styrenes such as 4-chlorostyrene or mixtures thereof, 
preferably styrene and .alpha.-methylstyrene and vinyl chloride. 
The quantity of monomer mixture used for graft polymerisation is preferably 
from 5 to 95% by weight, for 5 to 95 % by weight of an ethylene 
homopolymer or copolymer. 
The monomer mixture used for the grafting reaction may vary widely in its 
percentage composition of the given components. 
The monomer mixture consists of the following components: 
I. 4.99 to 94.99 % by weight, preferably 10 to 70 by weight and in 
particular 15 to 45 % by weight of (meth)acrylonitrile, 
Ii. 5 to 95 % by weight, preferably 20 to 89.9 % by weight, in particular 
54.9 to 80 % by weight of at least one aromatic monovinyl compound and 
Iii. 0.01 to 15 % by weight, preferably 0.1 to 10 % by weight and in 
particular 0.1 to 5 % by weight of vinyl chloride, 
the sum of components I to III being 100 %. 
The invention also relates to polymer-containing graft polymers of ethylene 
homopolymers or copolymers with polymerised units of mixtures of 
(meth)acrylonitrile, aromatic monovinyl compounds and vinyl chloride. 
The polymers preferably contain graft polymers of 
A: 5 to 95 % by weight, preferably 10 to 75 % by weight and in particular 
15 to 30 % by weight of ethylene homopolymer or copolymer and 
B: 95 to 5 % by weight, preferably 25 to 90 % by weight and in particular 
70 to 85 % by weight of polymerised units of 
I: 4.99 to 94.99 % by weight, preferably 10 to 70 % by weight and in 
particular 15 to 45 % by weight of (meth)acrylonitrile 
Ii: 5 to 95 % by weight, preferably 20 to 89.9 % by weight and in 
particular 54.9 to 80 % by weight of at least one aromatic monovinyl 
compound and 
Iii: 0.01 to 15 % by weight, preferably 0.1 to 10 % by weight and in 
particular 0.1 to 5 % by weight of vinyl chloride, 
the sum of A + B being 100 % and the sum of components I to III also being 
100 %. 
Particularly interesting are polymer-containing graft polymers of 
ethylene/vinyl ester copolymers with polymerised units of mixtures of 
(meth)acrylonitrile, aromatic monovinyl compounds and vinyl chloride. 
These polymers preferably contain graft polymers of 
A: 9 to 95 % by weight, preferably 10 to 75 % by weight and in particular 
15 to 30 % by weight of ethylene/vinyl ester copolymer and 
B: 91 to 5 % by weight, preferably 25 to 90 % by weight and in particular 
70 to 85 % by weight of polymerised units of 
I: 4.99 to 94.99 % by weight, preferably 10 to 70 % by weight and in 
particular 15 to 45 % by weight of (meth)acrylonitrile 
Ii: 5 to 95 % by weight, preferably 20 to 89.9 % by weight and in 
particular 54.9 to 80 % by weight of at least one aromatic monovinyl 
compound and 
Iii: 0.01 to 15 % by weight, preferably 0.1 to 10 % by weight and in 
particular 0.1 to 5 % by weight of vinyl chloride, 
the sum of A + B being 100 % and the sum of components I to III also being 
100 %. 
Particularly advantageous for certain purposes are graft polymers 
consisting of 
A: 5 to 95 % by weight, preferably 10 to 75 % by weight and in particular 
15 to 30 % by weight of ethylene/vinyl acetate copolymer containing 30 to 
75% by weight and preferably 40 to 55 % by weight of vinyl acetate built 
into the structure and 
B: 95 to 5 % by weight, preferably 10 to 75 % by weight and in particular 
70 to 85 % by weight of polyerised units of 
I: 4.99 to 94.99 % by weight, preferably 10 to 70 % by weight and in 
particular 15 to 45 % by weight of (meth)acrylonitrile, 
Ii: 5 to 95 % by weight, preferably 20 to 89.9 % by weight and in 
particular 54.9 to 80 % by weight of at least one aromatic monovinyl 
compound and 
Iii: 0.01 to 15 % by weight, preferably 0.1 to 10 % by weight and in 
particular 0.1 to 5 % by weight of vinyl chloride, 
the sum of A + B being 100 % and the sum of components I to III also being 
100 %. 
The monomers are mainly grafted on the graft substrate but minor quantities 
of homopolymers and/or copolymers of the monomers may also be present. 
The grafting reaction according to the invention may be carried out by 
introducing all the monomers and vinyl chloride into the reaction vessel 
in the presence of the graft substrate and polymerising, but alternatively 
the monomers or monomer mixtures and vinyl chloride may be added to the 
graft substrate either continuously or intermittently. 
The radical forming agent may be added in one portion at the beginning of 
the reaction or continuously or intermittently before, during or after 
addition of the monomers. In many cases it is advantageous to use several 
different radical forming agents in the reaction. 
For carrying out the grafting reaction, the graft substrate should 
preferably be in a finely divided or dissolved form if very homogeneous 
graft products are to be obtained but, in principle, the reaction may also 
be carried out with coarsely granulated polyethylene of the kind which is 
obtained, for example, from high pressure polymerisation of ethylene. 
If the grafting reaction is to be carried out in solution (homogeneous 
phase), the following solvents may suitably be used: Saturated aliphatic 
or aromatic hydrocarbons such as ethane, propane, the isomeric butanes, 
pentanes, hexanes or mixtures thereof, petroleum ethers, light fraction 
petroleum hydrocarbons and other petroleum hydrocarbon fractions, benzene, 
toluene, the xylene isomers and other substituted benzene derivatives such 
as chlorobenzene, halogenated aliphatic hydrocarbons such as methyl 
chloride, methylene chloride, chloroform, carbon tetrachloride, 
trichlorofluoromethane and other chloro-fluorohydrocarbons, 
trichloroethylene, tetrachloroethylene, difluoroethylene, etc. and low 
boiling alcohols such as methanol, ethanol, propanol, isopropanol or the 
isomeric butanols, preferably tertiary butanol. 
Dissolving of the graft substrates may be carried out at temperatures of 
from about 20.degree. C to 120.degree. C if fairly high boiling solvents 
are used or if the substrates are dissolved at elevated pressure. 
The grafting reaction may also be carried out in heterogeneous phase. In 
that case, the graft substrate may be used in the form of granulates, 
spherical particles, cylindrical particles, platelets or particles in the 
form of spirals or other shapes. 
If a heterogeneous phase is employed, the graft substrates are preferably 
in the form of powders or granulates with particles measuring from 1 .mu. 
to 3 cm. 
The graft substrates may be brought into contact with the monomer mixture 
by spraying, brush coating, dipping or dispersing the substrate in the 
monomer mixture, the monomers then partly or completely swelling into the 
substrate. 
The substrate particles may undergo an increase in volume but retain 
substantially their original shape. For the swelling process and for the 
subsequent grafting process, the monomer mixture may be used either 
undiluted or dissolved in solvents or dispersed in an organic diluent 
and/or water. The diluents used are similar to the solvents mentioned 
above which are used for carrying out the grafting reaction in solution. 
Whether the substrate particles are completely dissolved or merely undergo 
swelling depends on the quantity and nature of the solvent, the 
temperature, the pressure and the nature of the graft substrate. Swelling 
is, of course, accompanied by partial solution of the substrate particles, 
but the dissolved part of the individual substrate particle substantially 
remains in the undissolved part of the particle, with the result that the 
particle retains its original shape in spite of its increase in volume. 
Swelling of the graft substrates may be carried out at temperatures of up 
to about 85.degree. C, if desired in the presence of polymerisation 
catalysts. 
Graft copolymerisation may be carried out in homogeneous or heterogeneous 
phase at temperatures within a range of from -20.degree. C to 250.degree. 
C, preferably from 30.degree. C to 150.degree. C, and at pressures of up 
to 500 excess atmospheres, preferably at pressures of from normal pressure 
(1 atmosphere) to 21 atmospheres. 
The process could also quite well be carried out by first preparing a 
homogeneous phase of graft substrate, aromatic vinyl compound and vinyl 
chloride and optionally catalyst and solvent, then dispersing the solution 
in water and then polymerising, if desired after the addition of catalyst. 
Furthermore, the graft substrate particles which have been caused to swell 
by the monomer mixture, optionally in the presence of a radical forming 
agent, may be polymerised in the presence of inert or substantially inert 
gases such as nitrogen or carbon dioxide. 
When graft polymerisation is carried out in heterogeneous phase, the graft 
substrate which has undergone swelling is preferably present in an organic 
solvent or in water, or in a heterogeneous or homogeneous mixture of 
solvent and water. 
Graft copolymerisation may also be carried out as an emulsion 
polymerisation. In that case, a polyethylene latex or ethylene/vinyl ester 
copolymer latex having a solid content of from 20 to 55 % by weight, 
preferably 25 to 45 % by weight, is further polymerised to a given degree 
of conversion with continuous addition of the monomers and vinyl chloride 
on the one hand and of a water initiator solution which may additionally 
contain emulsifier on the other hand. 
The addition of vinyl chloride may, of course, be carried out at the onset 
of graft polymerisation, or the monomers and initiator solution may be 
added intermittently. This emulsion graft polymerisation process may also 
be carried out continously. Particularly suitable for use as initiators 
are water-soluble radical-forming agents such as potassium or ammonium 
peroxy disulphate or redox systems. Suitable emulsifiers include, for 
example, alkyl sulphates and alkyl sulphonates which have 12 to 24 carbon 
atoms in the alkyl group, hydrogenated or modified resinic acids such as 
Dresinate 731.RTM. of Hercules and saturated or unsaturated carboxylic 
acids which are modified with polyethylene oxide or propylene oxide. 
Biologically degradable emulsifiers are preferably used. 
The polymerisation catalysts are preferably added to the polymerisation 
mixture before, during or after the dissolving, swelling or mixing 
process. 
The polymerisation catalysts are preferably used in a quantity of from 0.01 
to 1.5 % by weight, based on the sum of graft substrate and graft 
monomers, although much larger quantities may, of course, be used if 
desired. 
Per-compounds or azo compounds which give rise to radicals may be used as 
polymerisation catalysts. The following are given as examples: Benzoyl 
peroxide, tert.-butyl perpivalate, lauroyl peroxide, tert.-butyl 
peroctoate, tert.-butyl perbenzoate, ditert.-butyl peroxide, tert.-butyl 
perisononanate, diisopropylpercarbonate, dicyclohexyl percarbonate, acetyl 
cyclohexylhexanesulphonyl peroxide, dicumyl peroxide, azo-bis-isobutyric 
acid nitrile, etc.. Benzoyl peroxide, tert.-butyl perpivalate, tert.-butyl 
peroctoate, dicyclohexylpercarbonate, dicumyl peroxide, azo-bis-isobutyric 
acid nitrile and ditert.-butyl peroxide are particularly suitable. 
When the process according to the invention is carried out in aqueous 
suspension, dispersing agents are necessary for obtaining satisfactory 
bead polymers. The following are given as examples of dispersing agents: 
Polyvinyl alcohol and partially saponified polyvinyl acetates, cellulose 
derivatives and starch derivatives such as methyl cellulose, ethyl 
cellulose or ethyl hydroxycellulose. Suitable synthetic dispersing agents 
(copolymers of hydrophilic and hydrophobic monomers) include 
styrene/(meth)acrylic acid, styrene/maleic acid anhydride and 
ethylene/(meth)acrylic acid copolymers; copolymers of (meth)acrylic acid 
esters and (meth)acrylic acid; polyethylene oxides or ethylene-propylene 
oxide copolymers and polyesters with hydroxyl numbers between 10 and 250. 
When mixtures of dispersing agents and emulsifiers are used, it is 
preferred to use biologically degradable emulsifiers. Inorganic salts (for 
example phosphoric acid derivatives) may also be used. Polymerisation in 
aqueous suspension is preferably carried out at temperatures of from 
40.degree. C to 150.degree. C at about 1 to 25 bar. 
The aqueous suspension polymerisation process may also be carried out as a 
reverse emulsion polymerisation (waterin-oil) or initially in the form of 
a reverse emulsion polymerisation and finally as a suspension 
polymerisation of styrene and acrylonitrile in water. 
In that case, a solution of the monomers and a radical forming agent 
(organic phase) is first prepared. Water is then added to the organic 
phase and a water-in-oil emulsion is produced, preferably with the aid of 
water-in-oil emulsifiers. The initiators or initiator system may be 
contained in the water. In the system which is to be polymerised, 
therefore, the disperse phase is formed by water which may contain part or 
all of the initiator or initiator system and of the monomers and 
water-in-oil emulsifier while the remaining monomers or all the monomers 
form the continuous phase. Copolymerisation may already set in during 
preparation of the water-in-oil emulsion. After formation of the 
water-in-oil emulsion (first stage), more water and, if indicated, 
dispersing agents are added to the water-in-oil emulsion with stirring at 
the second stage, at which phase reversal gradually takes place. An 
oil-in-water dispersion is formed, water substantially forming the 
continuous phase and oil the disperse phase. By the end of polymerisation, 
the oil droplets dispersed in water have completely solidified to form 
porous beads which contain water. The water-in-oil emulsifiers which are 
used in quantities of from 0.05 to 10 % by weight, preferably 0.5 to 4 % 
by weight, based on the monomers, may include, for example, graft products 
of styrene or other vinyl monomers on polyethers of ethylene oxide or 
styrene copolymers containing .alpha.,.beta.-unsaturated carboxylic acids 
or a 1:1 copolymer of methacrylic acid and methyl ,methacrylate. Other 
water-in-oil emulsifiers are also suitable, for example those described in 
British Patent Specifications Nos. 928,621; 926,699; 959,131; 964,195; and 
1,076,319; German Patent Nos. 1,300,286 and 1,211,655 and Belgian Patent 
No. 785,091. 
The proportion by weight of aqueous phase to organic phase when preparing 
the water-in-oil emulsion (first stage) should preferably be within the 
range of from 0.2:1 to 1:1 A ratio above or below this range may be used, 
so long as a water-in-oil emulsion can be formed but the ratio of aqueous 
phase to organic phase should not exceed 3:1. When preparing the 
water-in-oil emulsion, it is advisable always to add the aqueous phase to 
the organic phase. 
The vinyl chloride may be added with the solution of monomers or at a later 
stage but at the latest before phase reversal. 
The polymerisation temperatures during the first stage are from 30.degree. 
C to 120.degree. C, preferably from 60.degree. C to 85.degree. C. 
Polymerisation is preferably continued to a degree of conversion of from 
10 % to 60 %. 
In the second stage, the ratio by weight of aqueous phase to oil phase is 
preferably from 1:1 to 3:1 and should not be more than 10:1. Preparation 
of the water-in-oil emulsion may be carried out at temperatures of from 
10.degree. C to 90.degree. C. The addition of water and, if indicated, 
dispersing agents in the second stage is carried out after formation of 
the water-in-oil emulsion and heating or cooling to the polymerisation 
temperature of the second stage, which is from 40.degree. C to 180.degree. 
C, preferably from 75.degree. C to 150.degree. C. 
Substances which have been found suitable for use as dispersing agents are 
polyvinyl alcohol, partially saponified polyvinyl acetate and alkyl 
celluloses such as methyl cellulose, alkyl sulphonates or alkyl sulphates. 
They are used in quantities of from 0.01 to 3 % by weight, preferably 0.5 
to 2 % by weight, based on the quantity of monomers used. 
One particular advantage of this process lies in the simple method of 
processing and problem-free drying of the resulting bead polymer, which 
has a porous structure. 
The graft reaction according to the invention may also be carried out using 
known redox systems which may be composed of peracid compounds, such as 
potassium persulphate, and inorganic or organic reducing agents, for 
example as described in Methoden der Organischen Chemie, Houben-Weyl, 4th 
Edition (1961), Volume 14/1, pages 263-297. 
Initiator radicals may also be produced with the aid of ultraviolet 
irradiation which may be carried out in the presence of peracid compounds 
with or without sensitizer, X-rays, .gamma.-rays, or accelerated 
electrons. 
The usual additives such as molecular weight regulators may also be added 
to the polymerisation reaction mixtures, and, in the case of suspension 
polymerisation in organic solvents, special dispersing agents such as 
ethylene/vinyl acetate copolymers containing 45 to 80 % by weight of vinyl 
acetate or copolymers of (meth)acrylic acid derivatives may also be added. 
The process according to the invention may be carried out continously or 
batchwise. The grafting reaction may be carried out with or without 
solvent in polymerisation screws and evaporation of the solvent or of the 
residual monomers from the graft polymerisation mixture may be carried out 
in evaporation screws, thin layer evaporators or spray driers. 
In the process according to the invention, about 50 to 100 % by weight, 
preferably 80 to 100 % by weight of the styrene and/or (meth)acrylonitrile 
used as monomers become grafted. Extraction or fractional precipitation 
invariably yields only minor quantities or none at all of ungrafted 
styrene/acrylonitrile copolymer; in other words copolymer which has not 
become chemically linked with the substrate used. By contrast, if the 
process is carried out in a similar manner but without vinyl chloride, it 
is frequently found that about 50 % by weight or more of the 
styrene/(meth)acrylonitrile can be isolated from the reaction mixture as a 
copolymer which has not become grafted. 
Tables 1 and 2 show the results of fractional precipitation of a graft 
product prepared according to the invention (Example 1) and of a reaction 
product obtained by conventional methods (Comparison Example 1). The same 
ethylene/vinyl acetate copolymer was used as graft substrate in both 
experiments. 
Table 1 
______________________________________ 
Ungrafted 
Experiment SAN copolymer Toluene [.eta.] 
______________________________________ 
Example 1 -- 0.48 
Comparison 
Example 1 52 % by weight 2.31 
Ethylene/ 
vinyl acetate 
-- 1.37 
copolymer 
______________________________________ 
In the reaction product obtained in Comparison Example 1, 52 % by weight of 
the styrene/acrylonitrile mixture put into the process are present as 
ungrafted copolymer and the product has a relatively high intrinsic 
viscosity compared to that of the substrate used as starting material and 
the graft product prepared according to Example 1. 
The superior chemical uniformity of the graft product prepared according to 
the invention in Example 1 over the material prepared in the Comparison 
Example 1 can be seen from the following results of fractionation: 
Table 2 
______________________________________ 
Example 1: 
Acrylonitrile 
Vinyl chloride 
% by content (% by 
content (% by 
Fraction 
Weight [.eta.]DMF 
weight) weight) 
______________________________________ 
1 4.06 1.39 16.5 1.07 
2 26.46 1.02 20.8 1.06 
3 7.18 0.98 20.5 0.90 
4 11.53 0.95 21.2 1.14 
5 8.88 1.02 19.2 0.85 
6 12.16 1.01 21.4 0.58 
7 13.39 1.05 19.4 1.97 
8 14.42 1.00 17.3 1.02 
Remainder 
6.36 insoluble 
7.2 1.37 
in DMF 
______________________________________ 
Table 2 
______________________________________ 
Comparison Example 1: 
Acrylonitrile 
% by content 
Fraction Weight [.eta.]DMF 
(% by weight) 
______________________________________ 
1 10.5 insoluble 16.6 
2 50.9 3.08 19.0 
3 10.0 1.26 25.8 
4 14.5 0.76 25.0 
5 8.8 0.25 24.2 
6 2.25 0.15 16.0 
Remainder 0.3 
______________________________________ 
The reaction products obtained by the process according to the invention 
are therefore distinguished by the following characteristics: 
1. No ungrafted styrene/acrylonitrile copolymer; 
2. A graft product in which invariably more than 80 % by weight is 
chemically almost uniform in structure; 
3. The solubility properties indicated by the [.eta.] values obtained show, 
in addition to other findings, that the graft chains are relatively short 
and uniformly distributed over the graft substrate put into the process. 
By contrast, reaction products which have been prepared without the use of 
vinyl chloride as graft activator are not only chemically non-uniform but, 
according to their widely differing solution viscosities, they are also 
very non-uniform in their structure. This explains the difficulty with 
which such graft products can be processed thermoplastically and their 
undesirable inhomogeneity. 
The products of the invention are obtained as solutions, dispersions or 
solvent-free plastic masses, depending on whether the process was carried 
out in homogeneous or heterogeneous phase. For example, finely divided 
thermoplastic powders with an average particle size of less than 1000 .mu. 
which are excellent for coating purposes for various powder application 
methods such as whirl sintering, flame spraying and electrostatic 
spraying, or for rotational casting can be obtained directly by the 
process. 
The products obtained according to the invention are eminently suitable for 
use as coating materials and as material which can be thermoplastically 
processed. Even graft products with high styrene/acrylonitrile contents 
can be worked up problem-free in the usual machines used in thermoplastic 
technology. Owing to their excellent compatibility, the graft polymers are 
in some cases highly transparent. The mechanical strength properties are 
excellent, in contrast to those of mixtures of thermoplasts, which, as is 
well known, are completely incompatible and without mechanical strength.

The parts and percentages given in the Examples refer to weight unless 
otherwise indicated. 
To determine the proportion of grafted substance, the portions of ungrafted 
graft substrte were separated from the grafted substrate and ungrafted 
polymerised monomer units by simple and/or double fractional 
precipitation. For this purpose, the graft product was dissolved (e.g. in 
dimethylformamide, benzene or toluene/dimethylformamide mixtures), and 
then gradually precipitated in the heat, e.g. with n-butanol or methanol. 
The amount of graft substrate in the graft polymer is obtained from the 
difference between 100 % and the sum of percentages contents of the 
grafted monomers. 
The following standards were employed for the mechanical values measured in 
the Examples: 
Impact strength according to DIN 53 453 at room temperature unless 
otherwise indicated. 
Notched impact strength according to DIN 53 453 at room temperature unless 
otherwise indicated. 
Dimensional stability in the heat according to Vicat corresponding to DIN 
53 460 in .degree. C (described as Vicat temperature in the Examples). 
Ball pressure hardness according to DIN 53 456 
Bending stress according to DIN 53 452 
Tensile strength .delta..sub.B according to DIN 53 455 
Elongation .epsilon. according to DIN 53 455 
E-modulus according to DIN 53 457 
Stretching tension .delta..sub.S according to DIN 53 454. 
EXAMPLE 1 
580 g of an ethylene/vinyl acetate copolymer with a vinyl acetate content 
of 45 % by weight and a Mooney viscosity of 20 were dissolved at 
60.degree. C in 4000 cc of tertiary butanol and 1980 g of styrene in a 12 
l stirrer autoclave. 7.5 g of tert.-butyl perpivalate, 636 g of 
acrylonitrile, and 50 g of vinyl chloride in 1000 ml. of tert.-butanol 
were then added. The reaction mixture was stirred for 8 hours at 
60.degree. C and 2 hours at 80.degree. C. Solvent and remaining monomers 
were removed from the reaction mixture by steam. 3180 g of a graft polymer 
with an acrylonitrile content of 19.8 % by weight, a vinyl chloride 
content of 1.57 % by weight, a styrene content of 60.4 % by weight and an 
ethylene/vinyl acetate copolymer content of 18.23 % by weight were 
obtained. The mechanical properties of the graft polymers are shown in 
Table 3. 
EXAMPLE 2 
636 g of acrylonitrile, 6.5 g of tert.-butyl perpivalate, 4.5 g of 
ditert.-butyl peroxide, 200 ml of a 10 % solution of dispersing agent (the 
dispersing agent used was a 1:1 copolymer of methacrylic acid/methyl 
methacrylate in the form of an aqueous solution adjusted to pH 6), 0.8 g 
of sodium pyrosulphite and 2500 ml of water were added with stirring to a 
solution in 1920 g of styrene of 580 g of an ethylene/vinyl acetate 
copolymer which had a vinyl acetate content of 45 % by weight and a Mooney 
viscosity of 20. After the addition of 50 g of vinyl chloride, the mixture 
was heated to 80.degree. C. A solution of 18 g of sodium dihydrogen 
phosphate, 2.0 g of an alkylsulphate containing 12 to 14 C atoms in the 
alkyl chain and 3000 ml of water was pumped in at 80.degree. C at the rate 
of 750 ml/hour. The reaction mixture was then stirred for one hour at 
80.degree. C and 4 hours at 140.degree. C. The remaining monomers were 
removed from the reaction mixture by steam. 3160 g of a graft copolymer 
containing 18.8 % by weight of acrylonitrile, 1.58 % by weight of vinyl 
chloride, 18.3 % by weight of ethylene/vinyl acetate and 61.32 % by weight 
of styrene were obtained. The mechanical properties of the graft polymers 
are shown in Table 3. 
Table 3 
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Notched Ball 
Impact impact pressure 
Flexural 
strength strength Vicat hardness 
F-modulus 
Example 
(KJ/m.sup.2) 
(KJ/m.sup.2) 
.degree. C 
30"(N/m.sup.2) 
(KJ/m.sup.2) 
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1 unbroken 11.2 92 83 2242 
2 unbroken 14.7 98 92 2465 
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EXAMPLE 3 
4000 cc of water, 100 ml of a 10 % solution of dispersing agent (see 
Example 2), 200 ml of a 5 % methylcellulose solution in water, 8 g of 
benzoyl peroxide, 3000 g of an ethylene/vinyl acetate copolymer with a 
vinyl acetate content of 8.5 % by weight and a melt index at 190.degree. C 
and 2.16 kp loading of 5.1, 800 g of acrylonitrile, 300 g of styrene and 
170 g of vinyl chloride were introduced into a 12 l stirrer autoclave. The 
reaction mixture was heated with stirring to 50.degree. C for 8 hours and 
80.degree. C for 5 hours. 4160 g of a graft product with a vinyl chloride 
content of 4.0 % by weight, an acrylonitrile content of 17.5 % by weight 
and a styrene content of 6.5 % by weight were obtained on cooling. The 
graft product was rolled at 160.degree. C and pressed into plates. The 
mechanical properties were as follows: 
Tensile strength (kp/cm.sup.2): 156 
Elongation under tension (%): 661 
COMISON EXAMPLE 1 
580 g of an ethylene/vinyl acetate copolymer with a Mooney viscosity of 20 
were dissolved at 60.degree. C in 4000 cc of tert.-butanol and 1980 g of 
styrene in a 12 1 stirrer autoclave. 7.5 g of tert.-butyl perpivalate and 
636 g of acrylonitrile in 1000 ml of tert.-butanol were then added. 
Stirring was continued for 8 hours at 60.degree. C and 2 hours at 
80.degree. C. Solvent and residual monomers were removed from the reaction 
mixture with steam. 3070 g of a graft product with an acrylonitrile 
content of 18.3 % by weight and an ethylene/vinyl acetate copolymer 
content of 18.8 % by weight were obtained. 
The following mechanical properties could be measured: 
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Impact strength (KJ/m.sup.2) 
62 
Notched impact strength (KJ/m.sup.2) 
4.7 
Vicat .degree. C 96 
Ball pressure hardness 30"(N/m.sup.2) 
72 
Flexural E-modulus (KJ/m.sup.2) 
2356 
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