Note: Descriptions are shown in the official language in which they were submitted.
BASF AXtiengesellschaft 920673 O.Z. 0050/44505
- 213742~
Three-stage graft copolymers and thermoplastic molding materials
containing said copolymers and having great toughness
5 The present invention relates to
graft copolymers obtainable by
(A) polymerization of from 25 to 60% by weight of a mixture con-
sisting essentially of
(al)from 70 to 99.9% by weight of a Cl-Cl8-alkyl ester of
acrylic acid, where the alkyl radical may be monosubsti-
tuted by phenyl or phenoxy,
(a2)from 0.1 to 10% by weight of a polyfunctional monomer and
(a3)from 0 to 29.9% by weight of an ethylenically unsaturated
monomer which differs from (al) and (a2) and is copoly-
merizable therewith
in the presence of from 5 to 25% by weight of a crosslinked
silicone rubber
and
(B) polymerization of from 30 to 50% by weight of a mixture con-
sisting essentially of
(bl)from 50 to 100% by weight of a styrene compound of the
general formula (I)
RlC = CH2
~ I
R2
where Rl and R2 independently of one another are each hydro-
gen, Cl-C8-alkyl or Cl-C4-alkyl-monosubstituted, Cl-C4-alkyl-
disubstituted or Cl-C4-alkyl-trisubstituted phenyl, and/or of
a Cl-C8-alkyl ester of methacrylic or acrylic acid, and
(b2)from 0 to 50% by weight of a monomer selected from the
group consisting of methacrylonitrile, acrylonitrile,
methacrylic acid, acrylic acid, maleic anhydride, malei-
mide N-substituted by Cl-C4-alkyl, vinyl esters of
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
2137428
aliphatic C2-C8-carboxylic acids, acrylamide and vinyl
methyl ether,
in the presence of the graft copolymer (A).
The present invention furthermore relates to thermoplastic mold-
ing materials contA;n;ng the novel graft copolymers, processes
for the preparation of the novel graft copolymers and thermoplas-
tic molding materials, the use of the novel graft copolymers for
10 the preparation of thermoplastic molding materials and moldings,
the use of the novel molding materials for the production of
moldings, and moldings obtainable from the novel graft copolymers
and thermoplastic molding materials.
15 Graft copolymers cont~in;ng essentially a core of a silicone rub-
ber, a first shell based on an alkyl ester and an outer shell
based on a resin-forming monomer are disclosed, for example, in
EP-A 246,537. A disadvantage, however, is the fact that the low-
temperature toughness of molding materials and moldings prepared
20 therefrom is unsatisfactory.
The high proportion of silicone rubber in the graft rubbers,
stated in the examples, presents problems since silicone rubber
has a relatively high price compared with the other starting
25 materials.
Since the silicone rubber used has a very low glass transition
temperature Tg of -120 C (cf. DE 25 39 572; in contrast to buta-
diene rubber with -80 C or acrylate rubber with -40 C, cf.
30 European Patent 62901), it was expected that the low-temperature
toughness would increase with increasing proportion of silicone
rubber.
It is an object of the present invention to provide graft copoly-
35 mers which can be processed to give thermoplastic molding mater-
ials and/or moldings, the thermoplastic molding materials and
moldings which can be prepared therefrom having good low-
temperature toughness in conjunction with a low content of sili-
cone rubber.
We have found that this object is achieved by the graft copoly-
mers defined at the outset.
We have also found thermoplastic molding materials cont~;n;ng the
45 novel graft copolymers, processes for the preparation of the
novel graft copolymers and thermoplastic molding materials, the
use of the novel graft copolymers for the preparation of
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
2137~1~8
thermoplastic molding materials and moldings and the use of the
novel molding materials for the production of moldings, obtain-
able from the novel graft copolymers and thermoplastic molding
materials.
Suitable crosslinked silicone rubbers for the formation of the
novel core are in general crosslinked silicone rubbers comprising
units of the general formulae R2Sio~ RSiO3/2, R3Siol/2 and SiO2/4,
where R is a monovalent radical and, in the case of R3SiOl/2, may
lO furthermore be OH. The amounts of the individual siloxane units
are usually such that there are from 0 to 10 molar units of the
formula RSio3/2~ from 0 to 1.5 molar units of R3Siol/2 and from 0
to 3 molar units of SiO2/4 per 100 units of the formula R2Sio.
15 R is in general Cl-Clg-alkyl, preferably Cl-Cl2-alkyl, particularly
preferably Cl-C6-alkyl, such as methyl, ethyl, n-propyl, isoprop-
yl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl or hexyl, in
particular methyl or ethyl, or C6-Cl0-aryl, such as phenyl or
naphthyl, in particular phenyl, or Cl-Cl0-alkoxy or aryloxy, such
20 as methoxy, ethoxy or phenoxy, preferably methoxy, or groups
which can be attacked by free radicals, such as vinyl, allyl,
acryloyl, acryloyloxy, methacryloyl, methacryloyloxyalkyl, halo-
gen or mercapto, preferably vinyl or mercapto-Cl-Cl0-alkyl, in
particular mercaptopropyl, vinyl or methacryloyloxypropyl.
In a particular embodiment, silicone rubbers in which at least
80% of all radicals R are methyl are used. Silicone rubbers in
which R is methyl or ethyl are also preferred.
30 In a further embodiment, silicone rubbers which contain the
abovementioned groups which can be attacked by free radicals, in
amounts of from 0.01 to 10, preferably from 0.2 to 2, mol%, based
on all radicals R, are used. Such silicone rubbers are described
in, for example, EP-A 260 558 and EP A 492 376.
It is also possible to use the silicone rubbers described in
DE-A 25 39 572 or those disclosed in EP-A 370 347 as resins.
According to the invention, the core is used in an amount of from
40 5 to 25, preferably from 6 to 20, particularly preferably from 10
to 15, % by weight, based on the total amount of graft copolymer.
According to the invention, the component (A) is a mixture of es-
sentially
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
2137428
(al) from 70 to 99.9, preferably from 75 to 99.5, particularly
preferably from 80 to 99, % by weight of
a C1-C18-alkyl ester of acrylic acid,
where the alkyl radical may be
monosubstituted by phenyl or phenoxy,
(a2) from 0.1 to 10, preferably from 0.5 to 5, particularly
preferably from 1 to 4, % by weight of a
polyfunctional monomer and
(a3) from 0 to 29.9, preferably from 0 to 24.5, particularly
preferably from 0 to 19, % by weight of
an ethylenically unsaturated monomer
which differs from (al) and (a2) and is
copolymerizable therewith.
Preferably used C1-C18-alkyl esters of acrylic acid (com-
ponent (al)) are the C2-C8-alkyl esters, such as ethyl, n-propyl,
isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, pentyl,
20 hexyl, heptyl, n-octyl or 2-ethylhexyl acrylate, particularly
preferably ethyl, n-propyl, n-butyl or 2-ethylhexyl acrylate.
Furthermore, the C1-C18-alkyl esters may be substituted by phenyl
or phenoxy, phenyl-C1-C4-alkyl esters, such as benzyl acrylate,
phenylethyl acrylate, phenylpropyl acrylate or phenoxy ethyl
25 acrylate, being preferred. The substituted C1-Cl8-alkyl esters may
also be used as a mixture with unsubstituted C1-C18-alkyl esters
of acrylic acid, at least one C1-C18-alkyl ester of acrylic acid
preferably being used.
30 Examples of suitable polyfunctional monomers (component (a2)) are
vinylically unsaturated compounds having at least two double
bonds, such as
vinylbenzenes, such as divinylbenzene and trivinylbenzene,
35 triallyl cyanurate and triallyl isocyanurate,
diallyl maleate, diallyl fumarate and diallyl phthalate,
.
which usually have a crosslinking action.
40 Observations to date have shown that graft-linking unsaturated
monomers which may have a crosslinking action and carry epoxy,
hydroxyl, carboxyl, amino or anhydride groups, such as hydroxy-
C1-C6-alkyl methacrylates and hydroxy-C1-C6-alkyl acrylates, pre-
ferably hydroxyethyl methacrylate, hydroxyethyl acrylate,
45 hydroxypropyl methacrylate and hydroxypropyl acrylate, are also
suitable.
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
~137~28
The tricyclodecenyl acrylates Ia and Ib
~ o-c-CH = CH2 Ia
10 ~ ~ o-c-CH = CH2 Ib
have proven particularly suitable monomers for component (a2)
15 (cf. DE-A 1,260,135).
Preferably used ethylenically unsaturated monomers (com-
ponent (a3)) which differ from components (al) and (a2) but are
copolymerizable with these components are vinylaromatic monomers,
20 such as styrene, ~-methylstyrene, p-methylstyrene, tert-butyl-
styrene, l,l-diphenylethylene, monochlorostyrene and vinyl-
toluene, particularly preferably styrene;
acrylonitrile and methacrylonitrile, preferably acrylonitrile;
Cl-C4-esters of acrylic and methacrylic acid, such as methyl
25 methacrylate (MMA), ethyl methacrylate, n-propyl methacrylate,
isopropyl methacrylate, n-butyl methacrylate, isobutyl methacry-
late, sec-butyl methacrylate and tert-butyl methacrylate, methyl
methacrylate being particularly preferred, as well as mixtures of
these monomers;
methyl acrylate (MA), ethyl acrylate, propyl acrylate, n-butyl
acrylate, isobutyl acrylate, sec-butyl acrylate and tert-butyl
acrylate, methyl acrylate being particularly preferred, as well
as mixtures of these monomers;
C5 -C8-cycloalkyl esters of acrylic and methacrylic acid, such as
cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl acrylate and
cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl methacrylate,
preferably cyclohexyl methacrylate;
isobornyl methacrylate;
maleimides which are substituted at the imide nitrogen atom by
C1-C6-alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl,
45 isobutyl, sec-butyl, tert-butyl, pentyl or hexyl, preferably
N-methylmaleimide, and N-C6-C10-aryl- or N-C6-C20-aryl-Cl-C4-alkyl-
substituted maleimides, where the aryl groups may be mono-
BASF Aktiengesellschaft 920673 O.Z. OO50/44505
213742g
substituted, disubstituted or trisubstituted by C1-C4-alkyl, such
as N-phenylmaleimide and N-tolylmaleimide, preferably N-phenyl-
maleimide;
5 maleic anhydride and Cl-C6-alkyl maleates and di-C1-C6-alkyl mal-
eates, preferably maleic anhydride; and
dienes, such as butadiene and isoprene, preferably butadiene.
lO The glass transition temperature of the 1st shell (A) is usually
below 0 C, preferably below -20 C, particularly preferably below
-30 C (the glass transition temperature is determined, for exam-
ple, with the aid of DSC; K.H. Illers, Makromol. Chem. 127
(1969), 1).
The 1st shell (A) is prepared, as a rule, by known polymerization
methods, such as emulsion, mass, solution or suspension polymer-
ization, preferably in aqueous emulsion in the presence of an
aqueous emulsion of the silicone rubber core (cf. German
20 Patent 1,260,135).
The conventional emulsifiers, such as the alkali metal salts of
alkyl- or alkylarylsulfonic acids, alkylsulfates, fatty alcohol
sulfonates, salts of higher fatty acids of 10 to 30 carbon atoms
25 or resin soaps, may be used for the preparation of the grafting
base by emulsion polymerization. Sodium salts of alkylsulfonates
or of fatty acids of 10 to 18 carbon atoms are preferably used.
In general, emulsifiers are used in amounts of from 0.1 to 5,
preferably from 0.5 to 2, % by weight, based on the total weight
30 of the monomers used for the preparation of the 1st shell (A).
If desired, nonionic or anionic surfactants may be used as co-
emulsifiers. Nonionic coemulsifiers are, for example, polyoxy-
ethylene derivatives of fatty alcohols or fatty acids. Examples
35 are POE (3)-lauryl alcohol (POE = polyoxyethylene (x) where x is
the degree of polymerization), POE (20)-oleyl alcohol, POE (7)-
nonylphenol and POE (10) stearate. In general, a water/monomer
ratio of from 10 : 1 to 0.7 : 1 is used.
40 The polymerization initiators used are customary hydroperoxides,
the conventional persulfates and redox systems, such as hydroper-
oxide and ascorbic acid, if desired, with the addition of Fe2~
salts and complexing agents. The conventional redox systems are
known to a person skilled in the art. The amount of initiators
45 depends as a rule in a known manner on the desired molecular
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
2137~28
weight and is usually from 0.01 to 1, preferably from 0.05 to
0.5, % by weight, based on the total weight of the monomers.
The polymerization assistants used are in general the conven-
5 tional buffer substances, such as sodium bicarbonate or sodium
pyrophosphate (with which a pH of from 6 to 9 can be estab-
lished), and molecular weight regulators, such as mercaptans,
terpinols or dimeric a-methylstyrene.
10 The exact polymerization conditions, in particular the type, rate
of addition and amount of the emulsifier, are usually determined
specifically within the abovementioned ranges so that the result-
ing latex of the crosslinked polymer has a d50 value of from 40 to
2000 nm, preferably from 60 to 1000 nm, particularly preferably
15 from 80 to 800 nm.
For the preparation of the 1st shell (A) in aqueous emulsion,
temperatures of from 20 to 100 C, preferably from 40 to 80 C, are
usually employed.
According to the invention, the component (A) is used in an
amount of from 25 to 60, preferably from 30 to 55, particularly
preferably from 35 to 45, % by weight, based on the total amount
of graft copolymer.
According to the invention, the component (B), the 2nd shell, is
a mixture of essentially
(bl)from 50 to 100, preferably from 55 to 100, particularly pre-
ferably from 60 to 90, % by weight of a styrene compound of
the general formula I
RlC = CH2
~ I
~X2
where Rl and R2 independently of one another are each hydro-
gen, Cl-C8-alkyl or Cl-C4-alkyl-monosubstituted, Cl-C4-alkyl-
disubstituted or Cl-C4-alkyl-trisubstituted phenyl, and/or of
a Cl-C8-alkyl ester of methacrylic or acrylic acid
and/or
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
2137~28
(b2)from 0 to 50, preferably from 0 to 40, particularly prefer-
ably from 10 to 40, % by weight of a monomer selected from
the group consisting of methacrylonitrile, acrylonitrile,
methacrylic acid, acrylic acid, maleic anhydride, maleimide
N-substituted by Cl-C4-alkyl, vinyl esters of aliphatic
C2-C8-carboxylic acids, acrylamide and vinyl methyl ether.
Styrene, ~-methylstyrene, l,l-diphenylethylene and styrenes alky-
lated in the nucleus with Cl-C8-alkyl, such as p-methylstyrene or
10 tert-butylstyrene, particularly preferably styrene or ~-methyl-
styrene, are preferably used as the styrene compound of the gen-
eral formula I ~component (bl)).
According to the invention, methyl methacrylate (MMA), ethyl
15 methacrylate, n-propyl methacrylate, isopropyl methacrylate,
n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacryl-
ate, tert-butyl methacrylate, pentyl methacrylate, hexyl meth-
acrylate, heptyl methacrylate, octyl methacrylate or 2-ethylhexyl
methacrylate, particularly preferably methyl methacrylate, as
20 well as mixtures of these monomers, methyl acrylate (MA), ethyl
acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate,
sec-butyl acrylate, tert-butyl acrylate, pentyl acrylate, hexyl
acrylate, heptyl acrylate, octyl acrylate or 2-ethylhexyl acryl-
ate, particularly preferably n-butyl acrylate, as well as mix-
25 tures of these monomers with one another as well as with themethacrylates and/or styrene compounds of the general formula I
are used as Cl-C8-alkyl esters of methacrylic or acrylic acid.
According to the invention, a monomer selected from the group
30 consisting of methacrylonitrile, acrylonitrile, methacrylic acid,
acrylic acid, maleic anhydride, maleimide N-substituted by
Cl-C4-alkyl, vinyl esters of aliphatic C2-C8-carboxylic acids,
such as vinyl acetate or vinyl propionate, acrylamide and vinyl
methyl ether is, if desired, used as component (b2).
In a preferred embodiment, a mixture of styrene and acrylonitrile
(molar ratio usually from 10 : 1 to 1 : 1, preferably from 5 : 1
to 1 : 1) or a-methylstyrene and acrylonitrile (molar ratio usu-
ally from 10 : 1 to 1 : 1, preferably from 5 : 1 to 1 : 1) or
40 methyl methacrylate and styrene (molar ratio usually from 10 : 1
to 1 : 1, preferably from 5 : 1 to 1 : 1) or methyl methacrylate
alone, ie. without component (b2), is used.
BASF Aktiengesellschaft 920673 O.Z. OOS0/44505
` ~137428
The preparation of the 2nd shell (B) is carried out, as a rule,
by a conventional polymerization method, such as emulsion, mass,
solution or suspension polymerization, in the presence of the
graft copolymer (A).
However, it is advantageous to carry out the graft copolymeriza-
tion of component (B) on the polymer (A) serving as the grafting
base likewise in aqueous emulsion. It can be carried out in the
same system as the polymerization of the grafting base, and fur-
10 ther emulsifier and initiator may be added. These need not beidentical to the emulsifiers and initiators used for the prepara-
tion of the shell (A). The emulsifier, initiator and polymeriza-
tion assistants, either alone or as a mixture, may be initially
taken with the emulsion of the grafting base (A). Any possible
15 combination of initially taken material and feed on the one hand
and initiator, emulsifier and polymerization assistants on the
other hand is suitable. The preferred embodiments are known to a
person skilled in the art. The monomer mixture to be grafted may
be added to the reaction mixture all at once, batchwise in a
20 plurality of stages or continuously during the polymerization.
The novel graft copolymers preferably have a median particle size
- of from 0.1 to 10 ~m, particularly preferably from 0.1 to 1 ~m.
25 According to the invention, the component (B) is used in an
amount of from 30 to 50, preferably from 35 to 45, particularly
preferably from 35 to 40, % by weight, based on the total amount
of graft copolymer.
30 The novel graft copolymers thus prepared may be worked up by
known methods, for example by coagulation of the latices with
electrolytes (salts, acids or bases)~ by heating or freezing out,
by ultrasonics, by shearing or by a combination of these methods.
35 The novel graft copolymers may be used by themselves as molding
materials. For this purpose, they can be worked up, for example
by spray drying. However, the novel graft copolymers are prefer-
ably used for mixing with copolymer (C) in order to increase its
low-temperature toughness. Copolymers (C) suitable for modifica-
40 tion are obtainable, according to the invention, by polymeriza-
tion of a mixture consisting essentially of
(cl) from 50 to 100~ by weight of a styrene compound of the
general formula I and/or of a
C1-C8-alkyl ester of methacrylic
or acrylic acid,
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
~137928
(c2) from 0 to 50% by weight of a monomer selected from the
group consisting of
methacrylonitrile, acrylonitrile, methacrylic acid, acrylic acid,
5 maleic anhydride, maleimide N-substituted by C1-C4-alkyl, vinyl
esters of aliphatic C2-C8-carboxylic acids, acrylamide and vinyl
methyl ether,
(c3) from 0 to 90% by weight of a polycarbonate and
(c4) from 0 to 100% by weight of conventional additives.
The components (cl) and (c2) correspond to the components (bl)
and (b2) stated further above.
According to the invention, component (cl) is used in an amount
of from 50 to 100, preferably from 60 to 90, particularly prefer-
ably from 65 to 81, % by weight and component (c2) in an amount
of from 0 to 50, preferably from 10 to 40, particularly prefer-
20 ably from 19 to 35, % by weight.
Examples of the components (cl) and (c2) are homo- and copolymers
of a vinylaromatic monomer and a polar, copolymerizable, ethylen-
ically unsaturated monomer, such as polystyrene, polymethyl
25 methacrylate, styrene/acrylonitrile copolymers, a-methylstyrene/
acrylonitrile copolymers, styrene/maleic anhydride copolymers,
styrene/phenylmaleimide copolymers, styrene/methyl methacrylate
copolymers, methyl methacrylate/acrylonitrile copolymers, styr-
ene/acrylonitrile/maleic anhydride copolymers, styrene/acrylo-
30 nitrile/phenylmaleimide copolymers, a-methylstyrene/acrylo-
nitrile/methyl methacrylate copolymers, a-methylstyrene/acrylo-
nitrile/tert-butyl methacrylate copolymers and styrene/acrylo-
nitrile/tert-butyl methacrylate copolymers.
35 The stated copolymers are frequently formed as byproducts, for
example in the graft polymerization for the preparation of the
novel graft copolymers, particularly when large amounts of the
component (B) are grafted onto small amounts of the compo-
nent (A). The vinyl polymers and (meth)acrylate polymers can be
40 prepared by known free radical, anionic and cationic polymeriza-
tion methods. The known redox polymerization or the known poly-
merization with organometallic mixed catalysts may also be advan-
tageous.
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
213742g
11
Polycarbonate (PC), alone or as a mixture with the other compo-
nents (cl) and (c2) mentioned above, may be used as novel
component (c3).
5 Preferred novel blend components are, for example, mixtures of
polycarbonate with the novel graft copolymers described above and
the components (cl) and (c2).
Usually, the amount of the novel graft copolymers is from 5 to
lO 95, preferably from 10 to 90, particularly preferably from 20 to
80, % by weight, the amount of the components (cl) and (c2) (sum
cl + c2) is from 5 to 95, preferably from 10 to 90, particularly
preferably from 20 to 80, % by weight and the amount of component
(c3) is from 0 to 90, preferably from 0 to 80, particularly pre-
15 ferably from 0 to 70, % by weight.
Examples of suitable polycarbonates are those based on diphenolsof the general formula (II)
HO-Ar-A-Ar-OH (II)
where
25 A is phenyl which is unsubstituted or monosubstituted, disub-
stituted or trisubstituted by Cl-C4-alkyl or by halogen and
A is a single bond, Cl-C3-alkylene, C2-C3-alkylidene,
C3-C6-cycloalkylidene, -S- or -SO2-.
Preferred diphenols of the general formula (II) are, for example,
hydroquinone, resorcinol, 4,4'-dihydroxybiphenyl, 2,2-bis-(4-
hydroxyphenyl)-propane, 2,4-bis-(4-hydroxyphenyl)-2-methylbutane
and l,l-bis-(4-hydroxyphenyl)-cyclohexane. 2,2-bis-(4-Hydroxy-
35 phenyl)-propane and 1,1-bis-(4-hydroxyphenyl)-cyclohexane are
particularly preferred.
The diphenols of the general formula (II) are known per se or can
be prepared by known processes.
The diphenols of the general formula (II) may be used both indi-
vidually and as a mixture for the preparation of the
polycarbonates.
45 The suitable polycarbonates may be branched in a known manner,
preferably by the incorporation of from 0.05 to 2.0 mol%, based
on the sum of the diphenols used, of at least trifunctional com-
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
2137~28
12pounds, for example those having three or more phenolic OH
groups.
Polycarbonates which have proven particularly suitable are those
5 which have relative viscosities ~rel of from 1.10 to 1.50, in
particular from 1.25 to 1.40 (measured as 0.5~ strength by weight
solutions of the polymers in chloroform at 23 C). This corresponds
to weight average molecular weights Mw or from 10,000 to 200,000,
preferably from 20,000 to 80,000, g/mol.
The polycarbonates can be prepared, for example, by reacting the
diphenols of the general formula (II) with phosgene by the phase
boundary process or with phosgene by the process in the homogen-
eous phase (ie. the pyridine process), the molecular weight to be
15 established in each case being achieved in a known manner by a
corresponding amount of known chain terminators (with regard to
polydiorganosiloxane-contA;n;ng polycarbonates, cf. for example
German Laid-Open Application DOS 3,334,782).
20 Examples of suitable chain terminators are phenol and p-tert-
butylphenol, as well as long-chain alkylphenols, such as
4-(1,3-tetramethylbutyl)-phenol, according to German Laid-Open
Application DOS 2,842,005, or monoalkylphenols or dialkylphenols
having a total of 8 to 20 carbon atoms in the alkyl substituents,
25 according to DE-A 35 06 472, for example p-nonylphenol, 3,5-di-
tert-butylphenol, p-tert-octylphenol, p-dodecylphenol, 2-(3,5-di-
methylheptyl)phenol and 4-(3,5-dimethylheptyl)-phenol.
For example, polycarbonate/polysiloxane block copolymers, poly-
30 carbonate/polyether block copolymers and polycarbonate/polyester
block copolymers may also serve as component (c3).
As a rule, aromatic polyesters and polyester carbonates may also
be used as component (c3).
The novel thermoplastic molding materials may contain conven-
tional additives as further constituents (component (c4)).
Examples of these are dyes and pigments, light stabilizers, heat
40 stabilizers, plasticizers, blowing agents and organic or inorgan-
ic fillers in granular, powder or fibrous form.
The additives and assistants are used in conventional amounts,
preferably in amounts of up to 50~ by weight, based on the total
45 weight of the thermoplastic molding material. Compatible plastics
may also account for a higher proportion.
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
'~137428
_ 13
In addition to the polymers mentioned as matrices, the novel
graft copolymers may also be mixed with the following polymers:
polyphenylene ethers, polyamides, polyesters, polyurethanes,
polyethylene homo- and copolymers, polypropylene homo- and co-
5 polymers, halogenated polyolefins, such as polyvinyl chloride,
polytetrafluoroethylene and derivatives, as well as polyoxy-
methylenes, polyether ketones, polyether sulfones and
polysulfones.
lO In a further preferred embodiment, the novel graft copolymers are
mixed with known rubber-modified plastics, eg. ABS or ASA. ABS
(based on butadiene graft rubbers with styrene/acrylonitrile co-
polymer) and ASA molding materials (based on acrylate graft rub-
bers with styrene/acrylonitrile copolymer) are known to a person
15 skilled in the art and are described in, inter alia, German
Patent 1,260,135 and European Patent 62,901.
The novel thermoplastic molding materials are processed, as a
rule, by known methods, such as extrusion, injection molding,
20 compression molding of the melt, kneading, etc. The mixtures
melted in this manner are usually cooled and then processed to
give moldings (as a rule by injection molding)~ after which the
moldings are subjected to mechanical tests.
25 The novel thermoplastic molding materials can be processed by the
methods usually used for processing thermoplastics, such as ex-
trusion and injection molding, to give a very wide range of mold-
ings, such as window profiles, garden furniture, boats, sign-
boards, lamp coverings, automotive parts and toys. The novel
30 thermoplastic molding materials are particularly suitable for the
production of moldings which are required to have good low-tem-
perature toughness.
Examples
The notched impact strength aK (injection molding temperature/test
temperature) (in kJ/m2) was measured according to DIN 53 453, at
test temperatures of 23 C, 0 C and -20 C, using standard bars in-
jection molded at 220, 250 and 280 C.
The heat distortion resistance Vicat B 50 was determined accord-
ing to DIN 54 460 (in C).
The melt volume index MVI (in ml/10 minutes) was determined ac-
45 cording to DIN 53 735 at 200 C and under a load of 21.6 kg.
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
2137428
14
The stated median particle sizes are in all cases the weight
average of the particle sizes which were determined by means of
an analytical ultracentrifuge by a method corresponding to that
of W. Scholtan and H. Lange, Kolloid-Z. and Z.Polymere 250
5 (1972), 782 - 796. The ultracentrifuge measurement gives the in-
tegral mass distribution of the particle diameter of a sample.
From this it is possible to determine the percentage by weight of
the particles which have a diameter equal to or smaller than a
certain size. The median particle diameter, which is also re-
10 ferred to as a d50 value of the integral mass distribution, is de-
fined as the particle diameter at which 50% by weight of the par-
ticles have a diameter smaller than the diameter which corres-
ponds to the d50 value. Likewise, 50% by weight of the particles
then have a diameter greater than the d50 value.
1. Preparation of the graft copolymers A
1.1. The silicone emulsion (dispersion) A1 used was a cross-
linked polydimethylsiloxane emulsion (prepared similarly
to Example 1 in EP-A 492 376): solids content (SC):
17.4%; particle diameter 156 nm; viscosity 4.6 mPa-s;
pH 7; degree of crosslinking 3%; 0.5% of methacryloyloxy-
propyl functions.
25 1.2. Preparation of the 1st shell A2
1.2.1. Initially taken mixture
Dispersion A1 (cf. Table 1) and water were heated to 60 C
and
potassium persulfate (KPS) was then added.
1.2.2. Feed
A mixture of n-butyl acrylate (BA) and the acrylate of
tricyclodecenyl alcohol (DCPA) was added dropwise in the
course of 1.5 hours. At the same time, a mixture of water
and the sodium salts of a mixture of Cl3- and C14-alkyl-
sulfonic acids (soap) was added dropwise. The dispersion
A2 obtained was not isolated.
40 1.3. Preparation of the 2nd shell
5.1 g of potassium persulfate were added to the dispersion A2,
and 960 g of styrene and 320 g of acrylonitrile were
added dropwise in the course of 3 hours. Stirring was
carried out for a further 2 hours. Theoretical solids
content: 40.0~.
~ BASF Aktiengesellschaft 920673 O.Z. 0050/44505
~ 2137~28
Table 1
Preparation of siloxane/acrylate rubbers
All stated amounts in g
Experiment 1 2 3
Initially taken
mixture 1839 3678 5517
- component A1 3086 1575 255
lO _ water 4.8 3.9 2.88
- KPS
Feed
- BA 1568 1254 941
- DCPA 32 26 19
- water 212 206
- soap 8 4
Analysi~
20 Solids content 39.5 39.7 39.6
(%)
LT value 43 53 64
Swelling 4.4 4.6 4.2
indexl)
Gel contentl) 96.3 93.4 84.5
25 (%)
) The swelling index is the weight increase on swelling of the
sample in tert-butyl methyl ether at 23 C in the course of
24 hours. The gel content is the insoluble fraction obtained
after the above swelling, when the soluble fractions have
been separated off.
The light transmittance (LT; DIN 5036) is defined as the ratio of
the light transmitted by a sample to the intensity of the inci-
35 dent light. It must be measured as a function of the wavelengthin a range from 400 to 900 nm using an aqueous solution having a
solids content of 0.01% by weight, in a 3 cm thick quartz cell.
2. Comparative Experiment 1 (V1, silicone graft rubber)
In a glass flask, 8333 g of dispersion A1 were heated to 60 C,
3.9 g of potassium persulfate were added and a mixture of 725 g
of styrene and 242 g of acrylonitrile was added dropwise in the
course of 3 hours; the reaction was allowed to continue for a
45 further 2 hours.
BASF Aktiengesellschaft 920673 O.Z. 0050/44505
~137~g
16
Solids content SC: 25.7%
LT value: 79
Swelling index: 3.9
Gel content: 89.9%.
3. Comparative Experiment 2 (V2, acrylate graft rubber)
Preparation according to EP-8 6503, column 12, line 54, to
column 13, line 22.
The rubbers (Experiments 1 to 3, V1 and V2) were worked up as
described in EP-8 6503, column 13, lines 16 to 22.
4. Component B
A solution polymer of styrene and acrylonitrile in a weight ratio
of 65 : 35, having a viscosity number of 80 ml/g (measured at 23 C
in a 0.5% strength by weight dimethylformamide (DMF) solution),
was used.
5. Preparation of the mixtures
First, the rubbers (Experiments 1, 2 and 3 and V1 and V2) were
each mixed with the component 8 described in 4. in a weight ratio
25 of 1 : 1, the mixture was extruded at 250 C in a ZSK 30 twin-screw
extruder from Werner & Pfleiderer and the extrudate was granu-
lated. The granules were converted, at 220, 250 and 280 C, into
moldings for the mechanical test (Table 2).
30 Table 2
Mechanical data of the novel molding materials
Experiment 1 2 3 V1 V2
35 Vicat 850 88 87 87 92 87
(oc)
MVI 5.6 4.6 4.4 2.8 3.9
(200/21.6)
(ml/lOmin)
40 ak (kJ/m2) 22 24 21 12 26
(280/0) 18 19 16 8 5
(280/-20) 17 17 14 8 3
