Note: Descriptions are shown in the official language in which they were submitted.
2~ 3'7~3
~lastomer-Modified Polvar~lene Sulphide Mouldinq Compounds
This invention relates to thermoplastic moulding compounds
of polyarylene sulphides (PAS), preferably compounds of
polyphenylene sulphides (PPS~ and uncross-linked,
hydrogenated nitrile rubbers.
Partially crystalline polyarylene sulphides, e.g. poly-
phenylene sulphide, have properties which are disadvantageous
for certain uses, e.g. low stretchability and low toughness.
The applications in question include, for example, the
construction of moulded parts containing spring catches or
moulded parts which require ~O ~e after-treated for the form3ti~n of
beadings on the edges or the construction of cable sheaths
for cables with small radii of curvature. For these uses,
in which the moulded parts may be subjected to sin~le or repeated
considerable bending or impact stresses, the materials are
required to retain the advantageous properties of poly-
arylene sulphides.
Polyarylenç sulphides of low crystallinity, e.g. polyarylene
sulphides which are predominantly amorphous such as poly-
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diphenyl sulphone sulphide or copolyphenylene sulphidescontaining high proportions of m-phenylene sulphide units,
show these defects in properties only to a slight extent
but these polymers hardly have the typical properties which
are due to the crystallinity of the polymer.
It is known that partially crystalline thermoplasts,
including polyarylene sulphides, may be modified by the
introduction of rubbers to improve their toughness without
significantly altering their other properties. The
rubbers used may be graft rubbers based e.g. on diene or
acrylate rubber (e.g. EP-A 247 412, DE-A 3 616 131) or
uncross-linked, non-particulate rubbers based on EP, EPDM
or acrylate polymers ~e.g. EP-A 142 825) or styrene-butadiene
rubhers (~P-A 259 188).
The above mentioned rubbers differ greatly in their capacity
to improve the toughness of the compound and in some cases
cause considerable defects in certain properties, e.g.
thermal stability, oxidation resistance and chemical
resistance.
It has now heen found that polyarylene sulphides (PAS),
especially polyphenylene sulphide (PPS), may be modified hy
means of hydrogenated nitrile ruhhers so that the polymer
mixtures obtained are substantially improved in their
toughness and at the same time have high temperature
resistance and dimensional stability under heat as well as
high chemical resistance.
The present invention thus relates to polyarylene sulphide
moulding compounds, preferably polyphenylene sulphide
moulding compounds, containing:
A) from 30 to 99 5 parts by weight of polyarylene
sulphide, preferably polyphenylene sulphide,
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B) from 0-5 to 70 parts by weight, based on th~ ~ ~a~ 7
weight of the moulding compound of (A~B), of
hydrogenated nitrile rubbers,and optionally
C) from 0 to 60 parts by weight, based on the total
weight of the moulding compound of (AtB~C), of fillers
and reinforcing materials.
Polyarylene sulphides suitable for the purpose of this
invention are known (e.g. US-A 3 354 129 and EP-A 171 021)
and commercially available. The polyarylene sulphides may
be linear, branched or cross-linked.
The degree of hranching or cross-linking may be adjusted
by using multifunctional monomers for the synthesis of the
polyarylene sulphide or hy suitable after-treatments of
the predominantly linear polyarylene sulphide.
The following are examples of suitable polyarylene sulphides
for component A: polyphenylene sulphides, poly(alkylene-
phenylene)sulphides, polydiphenylene sulphides, polytetra-
phenylene sulphides, polynaphthylene sulphides, polyketone
sulphides, polys-1lphone sulphides, polyarylene sulphides
2(J containing heterocyclic monomer units and co-polyarylene
sulphides. Partially cr-ystalline polyarylene sulphides are
preferred. These are recognizahle by their melting and
crystallization temperatures in the ~SC. Poly-1,4-phenylene
sulphide is particularly preferred.
In reinforced compounds, the melt viscosities of the poly-
arylene sulphides used are from 20 to 170 Pa~s, preferably
frorn 35 to 80 Pa.s, and in unreinforced compounds the melt
viscosities are from 60 to 300 Pa.s, preferably from 80 to
200 Pa.s, determined in each case at 320C, 103(1/s).
The melt viscosities are determined in a conventional
commercial high pressure capillary viscosimeter at various
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shearing velocities (1/s) and at a temperature of the melt
of 320C. The ~m value (in Pa.s) at 10' (1/s) is given as
reference value from the viscosity function o~tained.
Components B in the context of this invention are
hydrogenated nitrile rubbers, i.e. copolymers of unsaturated
nitriles and conjugated dienes, in which the degree of
hydrogenation of the C=~ double honds is greater than 50%,
preferably greater than 70%, most preferahly greater than
~0%, especially greater than 98%, and the unsaturated
nitrile content is from 10 to 60% by weight, preferably
from 15 to 50% ~y weight, in particular from 18 to 48%
by weight.
The hydrogenated copolymers are gel free and soluble in
ketones such as acetone or butanone, in ethers such as tetra-
hydrofuran or dioxane and in chlorinated hydrocarbons suchas dichloromethane or chlorobenzene. "Selective hydrogenation"
in the context of this invention means the hydrogenation of
the olefinic C=C double bonds while the C-~1 tr~n!e ~onds are
preserved. "Preservation of the C~N ~riple ~onds" means in
this context that less than 7~, preferably less than 5~,
in particular less than 3~ and most preferably less than
1-5~ of the nitrile groups originally present in the
polymeric starting product undergo hydrogenation.
The hydrogenated copolymers under discussion here are
~5 o~tained by hydrogenating known alternatingiy or,preferably,
randomly structured copolymers of unsaturated nitriles and
conjugated dienes while retaining the nitrile groups (e.g.
US-A 3 700 637, DE-A 2 539 132, EP-A 134 023, DE-A 3 046
008 and D~-A 3 227 650).
Example~ of components B include the hydrogenation products
of copolymers of at least one unsaturated nitrile such as
acrylonitr`ile or methacrylonitrile and at least one
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;~ J 7~)
conjugated diene such as butadiene-(1,3); 2-methylbutadiene-
(1,3); 2,3-dimethylbutadiene-(1,3); pentadiene-(1,3) and a
product in which part of the conjugated diene units of the
above mentioned copolymers is replaced by one or more units
5 of aromatic vinyl compounds,~meth)acrylic acid esters having
1 to 12 carbon atoms in the alcohol component or
unsaturated mono- or dicarboxylic acids.
The following are examples of aromatic vinyl compounds:
styrene, substituted styrenes such as o-, m- or p-methyl
styrene, ethyl styrene, vinyl naphthalene and vinyl pyridine.
The following are examples of (meth)acrylic acid esters:
methyl(meth)acrylate, ethyl(meth)acrylate, n-butyl(meth)-
acrylate, 2-ethylhexyl(meth)acrylate and 2-hydroxypropyl-
(meth)acrylate. The following are examples of unsaturated
carboxylic acids~ -unsaturated monocarboxylic acids
containing 3 to 5 carbon atoms, such as acrylic acid, meth-
acrylic acid and crotonic acid, Q ,~ -unsaturated dicarboxylic
acids containiny 4 or 5 carbon atoms, such as maleic, fumaric,
citraconic and itaconic acid, and semiesters of the c,~ -
unsaturated dicarhoxylic acids, such as maleic acid n-dodecyl
semiester or fumaric acid n-butyl semiester.
The following are examples of other copolymerisable compounds
which may be used: vinyl chloride, vinylidene chloride,
N-methylol acrylamide, vinyl C1 to C4 alkyl ethers and vinyl
esters of carboxylic acids containing l to 18 carbon atoms,
such as vinyl acetate or vinyl stearate.
Special examples of the copolymers to be hydrogenated include
acrylonitrile-isoprene copolymers, acrylonitrile-isoprene-
butadiene copolymers, acrylonitrile-isoprene-n-~utyl
acrylate copolymers, acrylonitrile-butadiene-n-hutyl
acrylate copolymers, acrylonitrile-butadiene-methyl acrylate
copolymers, acrylonitrile-butadiene-2-hydroxypropyl meth-
acrylate copolymers and acrylonitrile-butadiene-methacrylic
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.
,: , . , - :. ~
n,~
acid copolymers. Acrylonitrile-butadiene copolymers are
particularly preferred.
The degree of hydrogenation of the polymers (percentage of
hydrogenated C=C double bonds based on the total number of
C--C double ~onds originally present in the polymer) is
determined by IR or NMR spectroscopy.
The molecular weights of the hydrogenated nitrile rubbers
are from 40,0~0 to 500,000 (g/mol), preferably from 50,000
to 400,000 (g/mol), in particular from 60,000 to 300,000
Ig/mol) (Mw, weight average, determined by gel permeation
chromatography).
The Mooney viscosities ~.L (1 ~ 4) 100C of the hydrogenated
nitrile rub~ers are generally in the range of from 10 to
150, preferably from 25 to 95 (determined according to DIN
53 523).
Components B may be present in quantities of from 0 5 to 70
parts hy weight, hased on the moulding compound of (A+B).
~hen fillers and reinforcing materials are used, components
B are preferably used in quantities of from 5 to 50 parts ~y
weight, more preferably from 10 to 4~ parts by weight,
especially from 10 to 30 parts by weight, based on the
moulding compound (A+B+C).
~n unreinforced polyarylene sulphides, component B is
preferahly added in quantities of from 5 to 40 parts by
weight, more preferably from 10 to 30 parts by weight and
most preferably from 15 to 25 parts by weight. The melt
flow properties due to the intrinsic viscosity in both
reinforced and unreinforced polyarylene sulphides is still
quite marked when the quantity of component ~ used, based
on the mou~ding compound, is from 0 5 to 20 parts by weight,
preferably from 1 to 15 parts by weight, most preferably from
2 to 10 parts ~y weight.
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0
Introduction of the components B used according to the
invention into the pol~arylene sulphide moulding compound
may be carried out by various methods, e.g. hy mixing of the
molten components in extruders or kneaders, but is preferably
carried out by melt compounding of the components in a two
shaft extruder of Werner 8 Pfleiderer or in an internal
kneader.
For ~elt compounding, co~ponents B are used in a dosable form. Powdered rub-
bers are preferred. These powders have par~i sl e
diameters of from 100/um to 3/um, preferably from 0 1 /um
to 2Jum, and are obtained by low temperature milling below
the glass temperature of the polymers.Io ~v~d the formation
of lum~s, suitable dusting agents are added to these
powders in quar.tities of from 1 to 1o% by weight, based on
the polymer. Suhstances of this kind are known, e.g. talc,
silicas, metal oxides, etc..
The fillers and reinforcing materials used as component
may be fihrous or particulate substances which shoulA ~e
sufficiently resistant to the temperatures at which the
polyarylene sulphides are processed and used. Examples of
fibrous materials for this purpose include glass ~ibres,
carbon fibres, aramide fibres, metal fibres, etc. Fxamples
of particulate suhstances include kaolin, gypsum, chalk,
talc, glass balls, mica, quartz, barium sulphate, metal
powders, etc.. The reinforcing fibres used are preferably
glass fibres or carbon fibres; preferred fillers are: quartz,
kaolin, talc and mica.
The fillers and reinforcing agents and other conventional
additives are introduced into the moulding compounds of
3~ (A+~) ~y melt compounding. These moulding compounds may be
thermo~lastically worked up as granulates in conventional
processlnq machines to produce any shaped products.
The mechanical and thermal properties were tested on standard
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2~ 7~
test samples in accordance with DIN or ASTM regulations. The
melt viscosities were determined on granulates, using a
high pressure capillary viscosimeter.
The mouldiny compounds according to the invention are
tougher than other polyarylene sulphides which have been
modified to increase their toughness, and they have good
temperature and chemical resistance. A pronounced intrinsic
viscosity of the polymer melt may be ohtained for processin~
by using suitable quantities of hydrogenated nitrile ru~ber
in the moulding compound.
The moulding compounds according to the invention may be
i used for the production of moulded articles, sheet products,
fi~res and wrapping materials.
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Example 1
PreParation_of the hvdroqenated nitrile rubbers
Acrylonitrile-butadiene copolymers are known.
Hydrogenation of these polymers and analytical determination
of their properties may be carried out e.g. by methods
analogous to those described in ~P-A134 023.
ExamPle 2
Preparation of the polyarylene sulphide mouldinq comPounds
The components are mixed together in the molten state at
temperatures from 310C to 330C in a two-shaft ZSK 32
extruder (Werner & Pfleiderer) at a rate of throughput of
from 7 to 10 kq/h. ~efore the components were compounded,
the hydrogenated nitrile rubber tn the form of sheets was
roughly size reduced or if in the fo~m of-bales, it ~as
ground to a powder and dusted with dusting agent. The
cooled polymer strands were granulated, dried, worked up
into moulded products in conventional injection moulding
machines and tested in accordance with DI~ regulations.
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* not broken
1) polyphenyle~e sulphide, Bayer AG, Tedu ~,
~m = 95 Pa.s (310C, 103 l/s)
2) hydrogenated nitrile rubber, Therban 1707~, Bayer AG,
acrylonitrile content 34%, 75 ML (1l4) 100C
3) Hydrogenated nitrile rubber, Therban 2207 ~ Bayer AG, acrylonitrile
content 42,5%, 80 ML (1+4h~00C, ground to a powder and powdered
with 6% by weight Vulcasi r from Bayer AG.
4) graft rubber based on acrylate, KM 33 ~, Rohm ~ Haas
5) graft rubber based on silicone, type A1 from DE-A 3
910 277
6) Izod impact strength
7) Izod knotched impact strength
8) edge fibre elongation
9) dimensional stability under heat according to ISO 75 A.
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