High molecular weight copolyarylene sulfide

The invention relates to high molecular weight, substantially linear copolyarylene sulfides predominantly containing biphenylene sulfide units, which are produced by reaction of aromatic halogen compounds and halobiphenylenes with sulfur donors in dipolar aprotic solvents, and to their use for moldings, films and fibers exposed to high temperatures and--preferably in reinforced form--as injection molding compounds.

This invention relates to high molecular weight, substantially linear 
copolyarylene sulfides predominantly containing biphenylene sulfide units, 
which are produced by reaction of aromatic halogen compounds and 
halobiphenylenes with sulfur donors in dipolar aprotic solvents, and to 
their use for moldings, films and fibers exposed to high temperatures 
and--preferably in reinforced form--as injection molding compounds. 
Polyarylene sulfides, particularly poly-p-phenylene sulfide (PPS), and 
processes for their production are known (cf. for example U.S. Pat. No 
3,354,129, EP-A 171 021). PPS is commercially available and, compared with 
some other partly crystalline thermoplastics from the group of polyamides 
and polyesters, shows better resistance to heat and chemicals and 
excellent inherent flame resistance. 
Nevertheless, there is a need in many fields of application, for example in 
the electronics field, for even higher heat resistance coupled with high 
resistance to chemicals and favorable processing properties of the 
thermoplastics. 
Relatively high heat resistance can be expected, for example, from polymers 
containing a relatively high proportion of aromatics. Examples of such 
polymers are polyarylene sulfides made up of biphenylene units. 
Polyarylene sulfides such as these are known (for example from U.S. Pat. 
No. 3,354,129). 
In addition to their high thermal stability, polyarylene sulfides of the 
type in question show very high resistance to chemicals which is 
consistent with the substantial chemical inertia of the polymer chain. 
On account of their extremely high melting points, they are difficult to 
process as thermoplastics. 
Copolyarylene sulfides of biphenylene sulfide and phenylene sulfide units 
have lower melting points than biphenylene sulfide homopolymers. The same 
applies in particular to mixtures thereof with PPS (cf. for example EP-A 
287 396). 
Although mixtures such as these can readily be processed as thermoplastics, 
particularly in reinforced form, they no longer have the superior 
properties of pure copolyarylene sulfides compared with PPS because the 
crystallization of these reinforced (for example glass-fiber-reinforced) 
mixtures is considerably reduced. This is reflected, for example, in a 
heat distortion temperature (for example HDT-A) which is the same as or 
lower than that of corresponding PPS compounds. The heat resistance of 
reinforced polyarylene sulfide mixtures can only be increased to a level 
above that of PPS by conditioning at temperatures below the melting point. 
It has now been found that pure copolyarylene sulfides based on biphenylene 
sulfide which, in addition, contain clearly defined smaller quantities of 
other arylene sulfide units can readily be processed as thermoplastics, 
even in reinforced form, in contrast to mixtures of such copolyarylene 
sulfides with PPS, and, at the same time, show greatly improved thermal 
properties. 
Copolyarylene sulfides of the type in question are partly crystalline and 
have melting points and glass transition temperatures above those of PPS. 
They have a sufficiently high crystallization rate and show distinctly 
improved heat resistance and long-term thermal stability compared with 
PPS. 
The melt viscosities at processing temperatures are comparable with those 
of PPS. 
It is known that biphenylene sulfide homopolymers and copolymers can be 
produced from 4,4'-dibromobiphenyl and sodium sulfide in N-methyl 
pyrrolidone by known methods for the synthesis of PPS (for example EP-A 
287 396). Although polybiphenylene sulfides such as these show improved 
thermal properties in relation to PPS, their molecular weight is 
comparatively low and their molecular non-uniformity very high. 
The high non-uniformity is reflected in a high oligomer content which can 
be seen before the main maximum of the molecular weight distribution in a 
high-temperature gel permeation chromatograph (as described, for example, 
in DE-A 3 529 498, see FIG. 2, Comparison Example I, and FIG. 4, 
Comparison Example III). 
It has now been found that biphenylene sulfide homopolymers and copolymers 
having distinctly higher molecular weights and a much lower molecular 
non-uniformity can be produced if 4,4'-dibromobiphenyl is replaced by 
4,4'-dichlorobiphenyl in their production. 
Polybiphenylene sulfides thus produced have comparable thermal properties, 
but--by virtue of their higher molecular weight--considerably better 
mechanical properties. 
The copolyarylene sulfides produced in accordance with the invention are 
made up of 50 to 95 mol-% (based on I + II) recurring biphenylene sulfide 
units corresponding to formula (Ia) or (Ib) 
##STR1## 
and 5 to 50 mol-% (based on I+II) recurring arylene sulfide units 
corresponding to formula (II) 
EQU --A--S-- (II) 
in which A represents --Ar--R--with 
Ar=C.sub.6-24 C aromatic radical other than biphenyl or a heterocyclic 
radical containing 5 to 14 ring atoms, up to 3 ring C atoms being 
replaceable by heteroatoms, such as N, O, S, or a C.sub.6-24 aromatic 
alkyl radical, and 
R=a single bond, O--Ar, S--Ar, 
##STR2## 
SO--Ar, SO.sub.2 --Ar where Ar is as defined above. 
These copolyarylene sulfides may additionally contain monomer units 
corresponding to formula (III) 
##STR3## 
in quantities of up to 5 mol-% and preferably in quantities of 0.1 to 0.5 
mol-%, based on the sum of the monomer units (I) and (II), Ar.sup.1 being 
an aromatic C.sub.6-24 radical, a heterocyclic radical containing 5 to 14 
ring atoms, up to 3 ring C atoms being replaceable by heteroatoms, such as 
N, O, S. 
The copolyarylene sulfides may optionally contain monomer units 
corresponding to formula (IV) 
EQU Ar--S-- (IV) 
where Ar is as defined for formula (II), at the end of the polymer chain in 
quantities of up to 5 mol-% and preferably in quantities of from 0.7 to 3 
mol-%, based on the sum of the monomer units (I) and (II) and optionally 
(III). 
Accordingly, the copolyarylene sulfides consist predominantly of recurring 
biphenylene sulfide monomer units and have the following physical 
properties: 
a) melting temperatures T.sub.M in the range of from 300.degree. C. to 
405.degree. C. 
b) a glass transition temperature T.sub.G in the range from 100.degree. C. 
to 195.degree. C. 
c) enthalpies of crystallization .DELTA.H.sub.k and enthalpies of fusion 
.DELTA.H.sub.M of more than 10 J/g 
d) a .DELTA.T, defined as .DELTA.=T T.sub.M -T.sub.K, where T.sub.K is the 
crystallization temperature of the polymer melt, below 40.degree. K. 
e) a melt viscosity .eta..sub.M at processing temperatures and at a shear 
rate of 10.sup.3 (1/s) of more than 10 Pa.s and less than 200 Pa.s. 
The thermal data T.sub.M T.sub.G, T.sub.K, H.sub.K and H.sub.M are 
determined by differential scanning calorimetry (DSC), for example using a 
Perkin-Elmer DSC 2, the sample being heated to approximately 30.degree. K. 
above the melting point at a heating rate of 20.degree. K/min., cooled to 
approximately room temperature at a cooling rate of 30.degree. K/min. 
after a residence time in the melt of at least 2 minutes and then reheated 
above the melting point at the same heating rate. T.sub.K is the maximum 
of the crystallization peak in the cooling curve of the melt, T.sub.M is 
the maximum of the melting peak during the second heating. The difference 
between T.sub.M and T.sub.K is a measure of the crystallization rate of 
the copolyarylene sulfide. 
The melt viscosities .eta..sub.M (eta-M), dimension (Pa.s), are measured in 
a commercial high-pressure capillary viscosimeter at a suitable melt 
temperature and at various shear rates .gamma. (gamma point), dimension 
(1/s). From the viscosity functions thus obtained, the melt viscosity at a 
shear rate of 10.sup.3 (1/s) in Pa.s is always as a comparison value. 
Since the copolyarylene sulfides have different melting points according 
to their chemical composition, it is not possible to state a single 
measurement temperature for all copolymers. Accordingly, a suitable 
melting temperature is the processing temperature of the particular 
copolyarylene sulfide and may be situated, for example, approximately 
30.degree. K. above the melt temperature T.sub.M determined by DSC. 
The copolyarylene sulfides have very different thermal properties, 
particularly T.sub.M, T.sub.K, .DELTA. H.sub.M, in dependence upon their 
chemical composition. For example, copolyarylene sulfides of 
4,4,-biphenylene sulfide units and 1,4-phenylene sulfide units show 
increasingly higher and narrower softening ranges or melting points 
T.sub.M with increasing content of biphenylene sulfide units. At the same 
time, the crystallization temperatures T.sub.K and also the enthalpies of 
crystallization and fusion .DELTA. H.sub.K and .DELTA. H.sub.M also 
increase. .DELTA. T (defined as .DELTA.T=T.sub.M -T.sub.K) also decreases 
in the same way. 
Sufficiently rapid and sufficiently high crystallization is desirable for 
the processing of these copolyarylene sulfides as thermoplastics. 
Accordingly, a high percentage content of biphenylene units (I) is 
favorable. Copolyarylene sulfides having a very high content of 
biphenylene units are suitable for processing as sintering powders, for 
example in sintering presses, or for coatings, whereas copolyarylene 
sulfides having a low content of biphenylene units tend to crystallize 
more slowly and incompletely. 
The choice of a suitable chemical composition of a copolyarylene sulfide 
for a specific application is determined not only by the thermal 
properties, but also by the particular molecular weights M.sub.w 
obtainable, as determined by high-pressure/temperature gel chromatography, 
or the melt viscosity, as determined by high-pressure capillary 
viscosimetry. Thus, the molecular weight M.sub.w of the copolyarylene 
sulfide decreases distinctly with increasing content of biphenylene units 
in the copolyarylene sulfide. At the same time, increasingly poor 
solubility of the copolyarylene sulfides in the reaction medium during the 
synthesis is observed. The level of the molecular weight obtainable is not 
without influence on the mechanical properties of the copolyarylene 
sulfides after processing. 
Copolyarylene sulfides having improved, balanced thermal and mechanical 
properties, so that they may readily be processed as thermoplastics, 
should contain the various monomer units in special clearly defined ratios 
to one another. 
In addition to the molar ratios of the monomer units, the isomer purity of 
the dihalobiphenyl used is of considerable importance, particularly with 
relatively high biphenyl contents. T.sub.M and T.sub.K can be appreciably 
reduced with increasing quantities of isomer impurities, such as for 
example 4,2'-isomers. 
Accordingly, the copolarylene sulfides preferably contain 65 to 80 mol-% 
4,4'-biphenylene sulfide units, the percentage content of other 
position-isomeric biphenylene sulfide units being less than 0.1 mol-% and 
preferably less than 0.03 mol-%, based on biphenylene sulfide units, and 
35 to 20 mol-% of 1,4-phenylene sulfide units with a percentage content of 
position-isomeric phenylene sulfide units of less than 0.1 mol-% and 
preferably less than 0.05 mol-based on phenylene sulfide units (the mol-% 
are based on the sum of the monomer units). 
The copolyarylene sulfides are further characterized by melting point 
maxima T.sub.M between 305.degree. and 375.degree. C., by crystallization 
maxima Tx of the solidifying polymer melts between 270.degree. C. and 
360.degree. C. and by enthalpies of crystallization and fusion between 20 
and 55 J/g, the higher values corresponding to the copolyarylene sulfides 
with the greater percentage content of biphenylene units. These thermal 
data are measured by DSC, as described above. 
The melt viscosities may be measured, for example, at 380.degree. C. and, 
for a shear rate of 10.sup.3 (1/s), are in the range from 10 to 180 Pa.s 
and preferably in the range from 20 to 100 Pa.s. 
These melt viscosities are determined in a high-pressure capillary 
viscosimeter, for example of the type made by Gottfert. To this end, the 
polymer melt accommodated in a correspondingly heatable channel 170 mm 
long and 9.5 mm in diameter, is forced through a nozzle 30 mm long and 1 
mm in diameter under loads of approximately 20 to 600 kg by means of a 
plunger. Different shear rates are produced by the different loads. 
The molecular weights M.sub.w (weight average; as measured by 
high-temperature gel chromatography, for example in accordance with DE-OS 
3 529 498) are in the range from 20,000 to 100,000 g/mol and preferably in 
the range from 30,000 to 60,000 g/mol, copolyarylene sulfides having a 
higher percentage content of biphenylene units tending to have lower 
molecular weights. The molecular weights and melt viscosities may be 
further increased by the additional introduction of branching agents 
(monomer units III). 
For comparable weight average molecular weights M.sub.w, polybiphenylene 
sulfides produced from 4,4'-dichlorobiphenyl have a lower non-uniformity 
than polybiphenylene sulfides produced from equal molar quantities of 
4,4'-dibromobiphenyl. 
The molecular non-uniformity U may be characterized by the following 
relation: 
##EQU1## 
where M.sub.w is the weight average molecular weight and M.sub.n is the 
number average molecular weight. 
The polymers produced in accordance with the invention have M.sub.w values 
in the range from 11,000 to 100,000 and U values in the range from 1.9 to 
4.9. 
For an experimentally determined M.sub.w value, there is an M.sub.n value 
which may be experimentally determined. For an experimentally determined 
M.sub.n value, there is an M.sub.w value which may be experimentally 
determined. 
The present invention relates to a process for the production of the 
copolyarylene sulfides described above and to the copolyarylene sulfides 
produced by this process, in which 
a) 50 to 95 mol-%, preferably 50 to 80 mol-% and more preferably 65 to 80 
mol-% dichlorobiphenyls corresponding to formulae (Va) and/or (Vb) 
##STR4## 
and 50 to 5 mol-%, preferably 50 to 20 mol-% and more preferably 35 to 20 
mol-% aromatic dihalogen compounds corresponding to formula (VI) 
EQU X--A--X (VI) 
in which A is as defined for formula II and X is halogen, preferably Cl, 
and 
b) 0 to 5 mol-% and preferably 0.1 to 0.5 mol-%, based on a), of an 
aromatic trihalogen or tetrahalogen compound corresponding to formula 
(VII) 
EQU Ar.sup.2 X.sub.n (VII) 
in which 
Ar.sup.2 is a C.sub.6-24 C aromatic radical other than biphenyl or a 
heterocyclic radical containing 5 to 14 ring atoms, up to 3 ring C atoms 
being replaceable by heteroatoms, such as N, O, S, or a C.sub.6-24 
aromatic alkyl radical, 
X is halogen, preferably chlorine, and 
n is the number 3 or 4, 
are reacted with 
c) alkali sulfides and/or alkali hydrogen sulfides, preferably sodium or 
potassium sulfide or mixtures thereof, preferably in the form of their 
hydrates or aqueous mixtures, optionally together with small quantities of 
alkali hydroxides, such as sodium and potassium hydroxide, the molar ratio 
of (a+b):c being from 0.75:1 to 1.25:1, 
d) optionally in the presence of catalysts, such as alkali carboxylates, 
alkali phosphates, alkali phosphonates, alkali fluorides, alkali alkyl 
sulfonates or N,N-dialkyl carboxylic acid amides, 0.2 to 50 mol-% and 
preferably 0.2 to 25 mol-%, based on mols aromatic dihalogen compounds, of 
an amino acid optionally being added to the reaction mixture, 
e) optionally in the presence of aromatic monohalogen compounds 
corresponding to formula (VIII) 
EQU R--Ar--X (VIII) 
in which 
X is halogen, such as Cl or Br, 
Ar is as defined for formula (VII), 
R represents H or has the meaning defined for formula (II), 
the reaction of the components being carried out in a polar aprotic solvent 
in the presence of an entraining agent at temperatures which enable the 
water to be simultaneously removed by distillation. The reaction is 
preferably carried out at normal pressure. 
Alkali sulfides can also be produced from H.sub.2 S and alkali hydroxides 
or from hydrogen sulfides and alkali hydroxides. 
The removal of water by distillation may be carried out directly or using 
entraining agents, the aromatic dihalogen compounds preferably being used 
as entraining agents. For the removal of water, all the reactants may be 
mixed and the water removed from the mixture as a whole. The reaction 
components may be added in any other order before and after the removal of 
water. 
Under typical reaction conditions, the removal of water by distillation 
using aromatic halogen compounds as entraining agents is limited by the 
molar ratios of the aromatic dihalogen compounds V and VI to one another, 
particularly with percentage contents of less than 20 mol-% aromatic 
dihalogen compounds VI. 
In cases such as these, water may be axeotropically removed from the alkali 
sulfide with a suitable excess of VI at temperatures below 200.degree. C. 
and, after the water has been removed, the excess of VI may be distilled 
off from the reaction mixture. Instead of using an excess of VI, other 
suitable inert entraining agents may be used to remove the water, being 
redistilled from the reaction mixture. The addition times or water removal 
times are preferably from 2 to 4 hours. Another variant of the removal of 
water from the alkali sulfide hydrate comprises azeotropic distillation in 
a separate preliminary step using a suitable entraining agent, such as for 
example toluene or mesitylene, optionally in the presence of catalysts as 
described under d). 
The very fine-grained anhydrous alkali sulfide isolated may be immediately 
introduced into the reaction with the aromatic halogen compounds and the 
solvent. 
The removal of water from the alkali sulfide hydrate may also be carried 
out by distilling off the water at elevated temperature in the absence of 
aromatic halogen compounds in a substantially inert, non-hydrolyzable 
aprotic dipolar solvent, such as for example N-methyl caprolactam or 
N,N-dimethyl imidazolidinone. The aromatic halogen compounds may be 
introduced together or separately into the anhydrous alkali sulfides in 
aprotic dipolar solvents, which may optionally contain the catalysts 
mentioned above, and reacted at temperatures above 200.degree. C. 
Where the removal of water is carried out in the presence of aromatic 
halogen compounds, the order in which the aromatic halogen compounds V and 
VI are added may be specifically varied to promote reactions of one group 
of aromatic halogen compounds with one another and thus to promote the 
formation of block copolymers over statistical copolymers. For example, 
the aromatic halogen compounds VI may be initially introduced into the 
reaction mixture and the aromatic halogen compounds V subsequently added 
and reacted, for example after the removal of water. 
All the reactants are preferably combined continuously together with amino 
acids in the presence of the polar solvent with simultaneous removal of 
the water. Where this procedure is adopted, an incipient reaction may be 
controlled through the addition rates. Prolonged residence times of the 
water can thus be avoided. 
Where the water is completely removed, the reaction may be carried out in 
the absence of pressure or under a low pressure of up to about 3 bar. To 
obtain higher reaction temperatures beyond the boiling point of the 
solvent or the mixture of solvent and aromatic dihalogen and polyhalogen 
compounds, higher pressures of up to 50 bar may be applied. 
The reaction times and temperatures in the range from 230.degree. C. to 
250.degree. C. are at least 5 hours and preferably more than 10 hours. The 
reaction time can be shortened by increasing the temperature under 
pressure or by using relatively high boiling solvents or by the presence 
of suitable catalysts. 
The reaction mixture may be worked up and copolyarylene sulfides may be 
isolated by methods known per se. 
The copolyarylene sulfides may be removed from the reaction solution in 
known manner, for example by filtration or centrifugation, either directly 
or after dilution with solvents or, for example, after the addition of 
water and/or dilute acids or organic solvents with minimal dissolving 
power for polyarylene sulfides. After the product has ben separated off, 
it is generally washed with protic solvents, for example water. Washing or 
extraction with other washing liquids (for example ketones, such as 
acetone), which may be carried out in addition to or after the main wash, 
is also possible. 
The reaction solution may also be solidified by suitable measures, 
subsequently taken up in the solvents mentioned and further processed as 
described above. 
According to the invention, it is possible to use aromatic dihalogen 
compounds corresponding to formulae V and VI and, optionally, aromatic 
monohalogen compounds corresponding to formula VIII or aromatic 
polyhalogen compounds corresponding to formula VII (as regulators). 
Examples of dihalodiphenyls corresponding to formulae (Va) and (Vb) 
suitable for use in accordance with the invention are 
2,5'-dichlorobiphenyl, 2,3'-dichlorobiphenyl, 2,2'-dichlorobiphenyl, 
3,4'-dichlorobiphenyl, 3,3'-dichlorobiphenyl, 4,4'-dichlorobiphenyl, 
4,2'-dichlorobiphenyl. 
The preferred aromatic dihalogen compound of formula V is 
4,4'-dichlorobiphenyl. It is particularly preferred to use a 
4,4'-dichlorobiphenyl having an isomer purity of more than 99.9% 
4,4'-position isomers and, more particularly, an isomer purity of greater 
than 99.95% 4,4'-dichlorobyphenyl. The isomer purity is determined by gas 
chromatography using calibration substances. 
Mixtures of different isomers, such as for example 4,2'- and 
4,4'-dichlorobiphenyl, can impair the thermal properties, such as melting 
and crystallization temperature, in some cases seriously, depending on the 
mixing ratio. Accordingly, high isomer purity is necessary for the 
synthesis of copolyarylene sulfides according to the invention having good 
thermal properties. 
Dichlorobiphenyls may be produced, for example, by known methods of 
sulfochlorination of biphenyl, which is highly selective, and subsequent 
elimination of SO.sub.2 ; the isomer purity can be maximized by suitable 
recrystallization. Another method comprises the direct chlorination of 
biphenyl using suitable zeolites. 
The following are examples of aromatic dihalogen compounds of formula VI 
suitable for use in accordance with the invention: 1,4'-dibromobenzene, 
1,4'-dichlorobenzene, 2,5-dichlorotoluene, 2,5-dichloroxylene, 
1-ethyl-2,5-dichlorobenzene, 1-ethyl-2,5-dibromobenzene, 
1-ethyl-2-bromo-5-chlorobenzene, 1,3,4,5-tetramethyl-2,5-dichlorobenzene, 
1-cyclohexyl-2,5-dichlorobenzene, 1-phenyl-2,5-dichlorobenzene, 
1-benzyl-2,6-dichlorobenze, 1-phenyl-2,5-dibromobenzene, 
1-p-tolyl-2.5-dichlorobenzene, 1-p-tolyl-2,5,-dibromobenzene, 
1-hexyl-2,5-dichlorobenzene, 1,5'-dichloronaphthalen, 
2.6'-dichloronaphthalene, 1,5-dichloroanthracene, 
4,4'-dichlorobenzophenone, 4,4'-dichlorodiphenyl sulfone, 
4,7-dichloroquinoline, 2,4-dichloro-1,3,5-triazine, 
2,6-dichlorobenzonitrile, 4,3'-dichlorophthalanil; they may be used 
individually or in admixture, preferably individually. 1.4-Dichlorbenzene 
is preferred. 
Examples of aromatic monohalogen compounds of formula VIII which may 
optionally be used in accordance with the invention are phenol, 
thiophenol, isooctylphenols, 4-mercaptobisphenyl, 3-chlorobiphenyl, 
4-chlorbiphenyl, 4-bromobiphenyl, 4-bromodiphenyl sulfide, 
4-chlorodiphenyl sulfide, 4-chlorodiphenyl sulfone, 
(4-chlorophenyl)-phenyl-ketone, (3-chlorophenyl)-phenylketone. The 
aromatic monohalogen compounds may be added before or during the reaction, 
individually or in the form of a mixture of aromatic halogen compounds or 
in portions at certain times during the reaction. 
Examples of aromatic trihalogen or tetrahalogen compounds corresponding to 
formula VII which may be used in accordance with the invention are 
1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4-tribromobenzene, 
1,3,5-trichloro-2,4,5-trimethylbenzene, 1,2,3-trichloronaphthalene, 
1,2,4-trichloronaphthalene, 1,2,6-trichloronaphthalene, 
2,3,4-trichlorotoluene, 2,3,6-trichlorotoluene, 
1,2,3,4-tetrachloronaphthalene, 1,2,4,5-tetrachlorobenzene, 2,2', 
4,4'-tetrachlorobiphenyl, 1,3,5-trichlorotriazine. 
Any polar solvent which guarantees adequate solubility of the organic and 
optionally inorganic reactants under the reaction conditions may generally 
be used for the reaction. N-alkyl lactams and cyclic N-alkyl ureas are 
preferably used. 
N-alkyl lactams are those of N-alkylamino acids containing 3 to 11 carbon 
atoms, which may optionally bear substituents inert under the reaction 
conditions on the carbon chain. 
Examples of N-alkyl lactams are N-methyl caprolactam, N-ethyl caprolactam, 
N-isopropyl caprolactam, N-isobutyl caprolactam, N-propyl caprolactam, 
N-butyl caprolactam, N-cyclohexyl caprolactam, N-methyl-2-pyrrolidone, 
N-ethyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-isobutyl pyrrolidone, 
N-propyl-2-pyrrolidone, N-butyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, 
N-methyl-3-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, 
N-methyl-3-methyl-2-pyrrolidone, N-methyl-3,4,5-trimethyl-2-pyrrolidone, 
N-methyl-2-piperidone, N-ethyl-2-piperidone, N-isobutyl-2-piperidone, 
N-methyl-6-methyl-2-piperidone, N-methyl-3-ethyl-2-piperidone. 
It is also possible to use bislactams attached to the nitrogen atom by 
alkylene groups, such as for example bis-(N-1,4-butylene)-caprolactam, 
bis-(N-1,6-hexylene)-caprolactam, bis-(N-1,4-butylene)-2-pyrrolidone. 
Examples of cyclic N-alkyl ureas are N,N-dimethyl imidazolidinone, 
N-N'-dimethyl-1,3-perhydrodiazin-2-one, 
N,N'-dimethyl-1,3-perhydrodiazepin-2-one. 
Mixtures of the solvents mentioned above may be used. 
the particularly preferred solvent is N-methyl caprolactam (NMC). 
Preferred amino acids are open-chain or cyclic aliphatic C.sub.1-20 amino 
acids which may contain lateral groups, such as for example .sub.1-4 
aloxythio-C.sub.1-4 -alkyl groups of a heterocyclic C.sub.6-14 group 
containing up to three heteroatoms, such as N, O, S. The amino group may 
be present as an NH.sub.2 -NRH or NR.sub.2 group, where R is an alkyl 
group, preferably a C.sub.1-4 alkyl group. Two groups R may also be 
situated at both ends of an alky chain with a lateral carboxyl group which 
forms a ring with the NH group. 
The amino group may be fixed in the 60 -, .beta.-, .gamma.- or 
.omega.-position. Diamino acids or aminocarboxylic acids may also be used. 
The following amino acids are mentioned by way of example: glycine, 
.alpha.-alanine, .beta.-alanine (.alpha.- and .beta.-aminopropionic acid), 
.alpha.-aminobutyric acid, .gamma.-aminobutyric acid, 
.alpha.-aminoisovaleric acid (valine), .alpha.-aminoisocaproic acid 
(leucine), .epsilon.-aminocaproic acid, 11-aminoundecanoic acid, 
N-methylaminoacetic acid (sarcosine), N-methyl-.alpha.-aminopropionic 
acid, N-methyl-.gamma.-aminobutyric acid, N-methyl-.epsilon.-aminocaproic 
acid, N-methyl11-aminoundecanoic acid, aminobutanedioic acid (aspartic 
acid), 2-aminopentanedioic acid (glutamic acid), 
2-amino-4-methylthiobutanoic acid (methionine), phenyl alanine, proline. 
The reaction may also be carried out in the presence of typical catalysts 
such as, for example, alkali carboxylates (DE-A 2 543 749), lithium 
halides or alkali carboxylates (DE-A 2 623 362), lithium chloride or 
lithium carboxylate (DE-A 2 623 363), alkali carbonates in combination 
with alkali carboxylates (U.S. Pat. No. 4,038,259), lithium acetate (DE-A 
2 930 710), trialkali phosphonates (DE-A 2 030 797), alkali fluorides 
(DE-A 3 019 732), alkali sulfonates (U.S. Pat. No. 4,038,260), lithium 
carbonate and lithium borate (U.S. Pat. No. 4,030,518). 
The reaction should preferably be carried out in apparatus which are unable 
to introduce any impurities into the reaction mixture in the form of metal 
traces, for example of Fe, Co, Ni or Cu in metallic or ionic form. 
Advantageous materials for parts of the reaction apparatus which are in 
contact with the reaction solution or with sulfide solution are titanium 
and special stainless steels. 
The present invention also relates to the use of the copolyarylene sulfides 
described above the production of moldings, fibers, films and injection 
molding compounds. 
To this end, the copolyarylene sulfides according to the invention may be 
mixed with fibrous and particulate fillers and reinforcing materials in 
quantities of up to about 70% by weight based on the sum of polymer plus 
filler (or reinforcing material). Examples of fillers are quartz, kaolin, 
mica, talcum, BaSO.sub.4, gypsum, glass beads, precipitated pyrogenic 
silica, metal oxides, such as TiO.sub.2 for example, metal sulfides, such 
as ZnS for example, carbon black, graphites, metal powders. Examples of 
reinforcing fibers are glass fibers, carbon fibers, whiskers, metal 
fibers, aramide fibers, boron nitride fibers. The fillers are reinforcing 
materials may be used individually or in admixture with one another. 
They may contain suitable sizes and coupling agents which promote 
attachment to the polymer, particularly in the case of glass fibers. 
Both in non-reinforced form and in reinforced form, the copolyarylene 
sulfides may contain typical additives, such as heat stabilizers, 
antioxidants, flow aids, pigments and/or mold release agents. 
Preferred fillers are quartz, kaolin, mica, talcum, gypsum, glass beads; 
preferred reinforcing materials are silanized glass fibers and carbon 
fibers, more particularly silanized glass fibers having a fiber diameter 
of 3 to 15 .mu.m and preferably of the order of 10 .mu.m. 
The fillers and reinforcing materials may be incorporated in the 
copolyarylene sulfides according to the invention by melt compounding of 
the components in standard units, such as for example kneaders, internal 
mixers or extruders, at melt temperatures approximately 30.degree. K. 
above the melting temperature T.sub.M of the copolyarylene sulfide. 
Kneaders and twin-screw extruders are preferably used. 
These reinforced copolyarylene sulfides may be processed to moldings of any 
kind in standard injection molding machines. To obtain thoroughly 
crystallized moldings, the mold temperatures must be sufficiently far 
above the glass temperatures, preferably 20.degree. to 30.degree. K. above 
T.sub.G. Thermal properties, such as heat resistance for example, may thus 
be optimally utilized. Another method of increasing heat resistance is to 
condition the moldings for periods of from about 2 to about 5 hours at 
temperatures 100.degree. to 150.degree. K. above T.sub.G or 50.degree. to 
100.degree. K. below the melting point T.sub.N of the copolyarylene 
sulfide. Heat resistance can be maximized in this way. 
The present invention also relates to the use of the copolyarylene sulfide 
for the production of films. The copolyarylene sulfides used for this 
purpose are preferably unfilled, although they may also contain finely 
divided fillers to obtain a certain surface roughness or coefficient of 
friction. The films may be produced in known manner by extrusion through a 
sheeting die. The processing temperature is 5.degree. to 80.degree. K. and 
preferably 10.degree. to 50.degree. K. above the melting point. The melt 
issuing from the die passes onto a rotating roller heated to a maximum 
temperature of 100.degree. to 120.degree. C. and is cooled below the 
crystallization temperature so rapidly that an amorphous film is formed. 
The film may be monoaxially or biaxially stretched at room temperature or 
at elevated temperature, preferably in the range from T.sub.g to T.sub.k. 
The stretching ratio may be from 4 to 14, preferably in the direction of 
the machine, and from 2.0 to 3.5 transversely thereof. The biaxial 
stretching may be carried out sequentially or simultaneously. The film is 
then heat-set at temperature above T.sub.k and below the melting 
temperature. 
The present invention also relates to the use of the copolyarylene sulfides 
for the production of filaments and fibers. 
The copolyarylene sulfides are spun by standard melt spinning processes, 
generally with no special requirements to be satisfied. The processing 
temperature is 5.degree. to 100.degree. C. above the melting point of the 
polymer and preferably 10.degree. to 50.degree. C. above the melting point 
of the polymer. 
The spun material is then stretched in the solid state. Stretching is 
carried out at room temperature preferably at elevated temperature, but 
always below the melting point of the polymer, more preferably at a 
temperature in the range from 70.degree. C. to 150.degree. C. The overall 
stretching ratio is preferably from 4 to 10. 
Stretching may be carried out, for example, in air, water or other heat 
transfer media or on contact heaters. 
Stretching may be carried out in one or more stages. 
The stretching process is preferably followed by a setting step, for 
example to improve the thermal properties, more especially by reducing 
boiling-induced shrinkage and thermal shrinkage. 
The setting step may be carried out continuously or discontinously, 
preferably continuously. 
The setting step may be carried out under tension or in the absence of 
tension, preferably under tension, at temperatures below the melting point 
of the polyarylene sulfide, preferably at a temperature up to 100.degree. 
C. and, more preferably, 50.degree. C. below the melting point. The 
residence times at those temperatures are from 1 second to 10 minutes and 
preferably from 10 seconds to 200 seconds. 
Fibers having a high degree of crystallinity can be produced in the setting 
step. 
The fibers according to the invention are distinguished by their 
problem-free production. No stabilizers are necessary to prevent the 
fibers from hardening during spinning, which could lead to the formation 
of gel particles. Nor is there any need for special filtration processes; 
standard die filters having bore diameters of 40 to 20 .mu.m are 
sufficient for preventing filament yarn breaks during spinning and 
stretching. 
Another advantage of the process according to the invention is that no 
gases are given off during processing of the polymers and the spun 
material is free from vacuoles. 
Spinning is carried out by standard melt spinning processes and does not 
involve any special precautions; in particular, any standard filament 
guides may be used. 
Compared with standard textile fibers, there is no increase in the 
frequency of filament breaks during spinning and stretching. 
The spun material obtained is not brittle, can be stretched without 
difficulty and crystallizes during a brief, continuous heat-setting step. 
The fibers and filaments according to the invention may be subjected 
without difficulty to standard textile processing. 
Commensurate with their high crystallinity, the fibers and filaments 
according to the invention are distinguished by high thermal stability, 
low boiling-induced and thermal shrinkage and by the minimal tendency to 
creep at high temperatures. The fibers and filaments according to the 
invention are also characterized by high strength, a high modulus of 
elasticity and high resistance to chemicals. 
the fibers and filaments according to the invention are also distinguished 
by their particularly high thermal stability which is up to about 
70.degree. K. higher than the thermal stability of normal polyphenylene 
sulfide. 
Thermal stabilities as high as this are otherwise only achieved by 
considerably more expensive materials, for example polyether ketones and 
polyimides.

The fibers and filaments according to the invention are suitable, for 
example, for the production of protective clothing, nonwovens, for example 
for filtration and for electrolysis membranes. 
EXAMPLE 1 
(70 MOL-% biphenyl sulfide units, PAS-B-70) 
3,105 g N-methyl caprolactam (NMC), 232.8 g (1.58 mol) 1,4-dichlorobenzene 
and 824 g (3.69 mol) 4,4'-dichlorobiphenyl are introduced under nitrogen 
into and heated to 210.degree.-215.degree. C. in a 5 liter tank reactor 
equipped with a stirrer, thermometer, heavy-phase water separator, reflux 
condenser and dropping funnel. A solution heated to approximately 
80.degree. C. of 742 g sodium sulfide hydrate (5.80 mol Na.sub.2 S) and 
89.6 g (0.79 mol) .epsilon.-caprolactam in approximately 260 g water is 
then added dropwise with vigorous stirring over a period of 90 to 120 
minutes at such a rate that the water introduced can be azeotropically 
removed at the same time with 1,4-dichlorobenzene. To maintain 
stoichiometry, the 1,4-dichlorobenzene distilled off is returned to the 
tank reactor after separation of the water. After the addition and after 
the water has been removed, the mixture is slowly heated to 23020 C. and 
stirred for another 25 h at .gtoreq.230.degree. C. The polyarylene sulfide 
is worked up by precipitation of the reaction mixture with vigorous 
stirring in a large excess of isopropanol, filtration and washing of the 
residue with isopropanol. 
The residue is taken up in water, acidified to pH 1-2 with aqueous H.sub.2 
SO.sub.4 and washed with water until neutral, followed by drying for 12 h 
at 120.degree. C. in a vacuum drying cabinet. The polyarylene sulfide has 
a maximum melting point of 355.degree. to 358.degree. C. and an M.sub.w of 
35,300 (see FIG. 1). 
EXAMPLE 2 
2,464 g N-methyl caprolactam, 202.4 g 1,4-dichlorobenzene and 358.4 g 
4,4'-dichlorodiphenyl are introduced into, and heated to the reflux 
temperature in, a 5 liter tank reactor equipped with a thermometer, 
stirrer, coolable column, distillate divider, reflux condenser and two 
dropping funnels. A mixture of 647.8 g sodium sulfide hydrate (approx. 60% 
sodium sulfide), 103.9 g caprolactam and 262 g water is added dropwise 
over a period of 90 minutes at such a rate that the water introduced can 
be simultaneously removed azeotropically with 1,4-dichlorbenzene. At the 
same time, another 358.4 g 4,4'-dichlorodiphenyl in 460 g N-methyl 
caprolactam are added to the reaction mixture over a period of 
approximately 70 minutes. To maintain stoichiometry, the 
1,4-dichlorobenzene distilling off is returned to the reaction mixture 
after removal of the water. After the addition and after the water has 
been removed, the column is switched to reflux, the reaction mixture is 
heated at the reflux temperature for another 25 hours and the product is 
then isolated in the usual way. The product has a melting point Tm of 
369.degree. C. and Mw of 14,000. 
EXAMPLE 3 
The procedure is as in Example 1, except that 4.2 g 1,3,5-trichlorobenzene 
were additionally introduced. The product had a melting point of 
354.degree. C. and an Mw of 65,000. 
COMISON EXAMPLE I 
(Example (b) of EP-A 287 396, half batch size) 
39 g (0.125 mol) 4,4'-dibromobiphenyl, 18.4 g (0.125 mol) 
1,4-dichlorobenzene and 19.5 g (0.25 mol) sodium sulfide, anhydrous, were 
polymerized for 5 hours at 220.degree. C. in the presence of 6.75 g water, 
248 g N-methyl pyrrolidone and 1 g sodium hydroxide. A pressure of approx. 
5 bar was reached. When melted for the first time, the product had a 
melting point of 370.degree. C. which was no longer observed in the second 
melting. It had an Mw of 11,800 with pronounced bimodal distribution. 
COMISON EXAMPLE II 
(PAS-B-50 from dichlorobiphenyl) 
The procedure was as in Example 1, except that 588.4 g (2.635 mol) 
4,4'-dichlorobiphenyl and 386.5 g (2.635 mol) 1,4'-dichlorobenzene are 
used. 
COMISON EXAMPLE III 
(PAS-B-70 from dibromobiphenyl) 
The procedure was as in Example 1, except that 1,152.7 g (3.69 mol) 
4,4'-dibromobiphenyl, 232.8 g (1.58 mol) 1,4'-dichlorobenzene and 4,000 g 
NMC are used. 
TABLE 1 
______________________________________ 
(Comparison of bromo- and chlorobiphenylenes) 
4,4'di- 4,4-di- 1,4-di- 
bromobi- chlorobi- 
chloro- 
phenyl phenyl benzene Sol- 
Example (mol-%) (mol-%) (mol) vent -- M.sub.w 
______________________________________ 
Ex- -- 70 30 NMC 35,300.sup.1) 
ample 1 
(inven- 
tion) 
Comp. III 
70 -- 30 NMC 11,700.sup.2) 
Comp. I 50 -- 50 NMC 11,800.sup.3) 
Comp. II 
-- 50 50 NMC 77,800.sup.4) 
(inven- 
tion) 
______________________________________ 
.sup.1) see FIG. 1, 
.sup.2) see FIG. 4, 
.sup.3) see FIG. 2, 
.sup.4) see FIG. 3 
EXAMPLE 4 
(PAS-B-70, low molecular weight) 
The procedure and reaction mixture are as in Example 1, except that the 
reaction is terminated after 8 h at a reaction temperature of 230.degree. 
C. and the reaction product is worked up as previously described. The 
polyarylene sulfide has an M.sub.w of 13,400. 
TABLE 2 
______________________________________ 
(Non-uniformity U in dependence upon the aromatic halogen 
compounds used) 
4,4'-dibromo- 
4,4'-dichloro- 
biphenyl biphenyl 
Example mol-% mol-% -- M.sub.w 
U 
______________________________________ 
Ex. 4 -- 70 13,400 
1.90 
(inven- 
tion) 
Comp. III 
70 -- 11,700 
3.45 
______________________________________ 
EXAMPLE 5 
(PAS-B-60) 
The procedure is as in Example 1, except that 614.4 g (2.75 mol) 
4,4'-dichlorobiphenyl, 270 g (1.84 mol) 1.4-dichlorobenzene, 636.3 g 
sodium sulfide hydrate (4.93 mol Na.sub.2 S), 77.9 g (0.60 mol) 
caprolactam and 2,820 g NMC are used. 
EXAMPLE 6 
(PAS-B-65) 
The procedure is as in Example 5, except that 665.6 g (2.98 mol) 
4,4'-dichlorobiphenyl, 236.2 g (1.61 mol) 1,4-dichlorobenzene and 2,890 g 
NMC are used. 
EXAMPLE 7 
(PAS-B-75) 
The procedure is as in Example 5, except that 768 g (3.44 mol) 
4,4'-dichlorobiphenyl, 168.7 g (1.15 mol) 1.4-dichlorobenzene and 2,990 g 
NMC are used. 
EXAMPLE 8 
(PAS-B-80) 
The procedure is as in Example 5, except that 819 g (3.67 mol) 
4,4'-dichlorobiphenyl, 135 g (0.92 mol) 1,4-dichlorobenzene and 3,050 g 
NMC are used. 
TABLE 3 
______________________________________ 
(Effect of the biphenylene sulfide component on the physi- 
cal properties of the PAS-B) 
DSC (dynamic, 20.degree. K./min) 
Ex- Mol-% .DELTA.H.sub.S 
.DELTA.H.sub.K 
ample biphenyl -- M.sub.w 
T.sub.S (.degree.C.) 
(I/g) 
T.sub.K (.degree.C.) 
(I/g) 
______________________________________ 
5 60 54,100 293/367 21 273 10 
6 65 49,800 303/368 24 310 23 
1 70 35,300 358 31 332 29 
7 75 18,800 368 48 354 32 
8 80 15,000 380 63 364 38 
______________________________________ 
Production of molding compounds: 
The copolyarylene sulfide molding compounds according to the invention were 
produced by mixing and homogenizing the basic components in a Werner & 
Pfleiderer ZSK 32 twin-screw extruder at a melt temperature of 370.degree. 
C. The strands reduced to granulate were dried overnight and processed in 
standard injection molding machines to standard test specimens which were 
tested to DIN and ASTM standards (see Table 4). 
TABLE 4 
______________________________________ 
(Injection molding compounds) 
Example 
9 10 11 12 
Invention 
Comp. 10a.sup.7) 
Comp. Comp. 
______________________________________ 
PAS-B-70.sup.1) 
60 42 24 -- 
PPS.sup.2) 
-- 18 36 60 
Glass 40 40 40 40 
fibers.sup.3) 
E-modulus 
11,200 13,400 12,100 
12,300 
in bend- 
ing [Mpa] 
.epsilon. 6B.sup.4) [%] 
1.7 1.7 1.3 1.9 
HDT-A.sup.5) 
290 253 280 251 260 
[.degree.C.] 
.eta..sup.-- M.sup.6) [Pa .multidot. s] 
______________________________________ 
.sup.1) Produced in accordance with Example 1 
.sup.2) Tedur PPS, --M.sub.w 38,000 
.sup.3) Sized 10 .mu.m glass fibers, 6 mm long 
.sup.4) Outer fiber strain in bending test 
.sup.5) Heat distortion temperature, method ISO80 
.sup.6) Melt viscosity at 380.degree. C. at a shear rate of 10.sup.3 
(1/s), as measured in a highpressure capillary viscosimeter 
.sup.7) Test specimen of Example 10 conditioned for 5 h at 250.degree. C. 
In Example 9 according to the invention, higher heat distortion 
temperatures are obtained without conditioning than with mixtures of 
polybiphenylene sulfides and PPS. 
EXAMPLE 13 
Production of films 
Using a ZSK 32 twin-screw extruder, the copolyarylene sulfide produced in 
accordance with Example 3 and, for comparison, a commercial polyphenylene 
sulfide (Fortron 300 B, a Celanese product) are extruded from a 400 mm 
wide flat film die (gap width 1.0 mm) at 350.degree. to 390.degree. C. The 
melts issuing from the die are processed to 350 mm wide, 0.5 mm thick 
films on a four-roll stand. Since the temperature of the first take-off 
roller with which the polyphenylene sulfides melts come into direct 
contact is 30.degree. C., amorphous films are obtained. 
300.times.300 mm pieces of these films are then placed in a stretching 
frame and stretched in a ratio of 1:3 at 160.degree. C. first in the 
extrusion direction and then transversely thereof. The stretching rate is 
6 cm/s. Two parallel constrictions are observed transversely of the 
particular stretching direction, only disappearing at the end of the 
stretching process. 
Their thickness is only 0.05 mm. After stretching, the films are heated for 
20 minutes at 300.degree. C. in the stretching frame. The mechanical 
properties are shown in Table 5. 
TABLE 5 
______________________________________ 
Films of polyarylene 
sulfide according 
to Example 13 Comparison 
______________________________________ 
Tensile strength 
Longitudinal 
235 200 MPa 
Transverse 212 190 MPa 
Elongation at break 
Longitudinal 
40% 35% 
Transverse 50% 45% 
Tm as measured on the 
-- 348.degree. C. 
281.degree. C. 
film 
______________________________________ 
Pieces of the film of Example 5 heated for 2 hours at 280.degree. C. show 
less than 0.3% shrinkage. 
EXAMPLE 14 
Fibers according to the invention 
The polymer produced in accordance with Example 3 was extruded through a 
0.5 mm diameter single-bore die in a melt-spinning extruder. The 
monofilament was cooled in a water bath; the take-off rate was 200 
m/minute. The monofilament was stretched in two stages on contact heaters 
at 160.degree. C. (overall stretching ratio 5.3). The monofilament thus 
obtained showed the following textile data: 
denier 23 dtex 
fineness strength 3.2 cN/dtex 
elongation at break 13% 
initial modulus 39 cN/dtext 
boiling-induced shrinkage 13%. 
Wide-angle X-ray scattering of these fibers revealed a high degree of 
orientation, but only minimal crystallinity. 
The monofilament was set under tension for 2 minutes on a godet heated to 
320.degree. C. The following textile data were obtained: 
denier 24 dtex 
fineness strength 3.3 cN/dtex 
elongation at break 17% 
initial modulus 44 cN/dtex 
boiling-induced shrinkage &lt;0.2% 
shrinkage in hot air at 240.degree. C. &lt;0.2% 
A creep test, in which 10 cm of the monofilament was heated from room 
temperature to 300.degree. C. under a load of 0.1 cN/dtex and was kept at 
300.degree. C. for 1 hour, produced an elongation of 1.2% after 1 hour. 
The wide-angle X-ray scattering of this monofilament revealed a highly 
oriented crystalline structure. After heat treatment in air for 24 hours 
at 300.degree. C. in the absence of tension, the set monofilament had the 
following textile data: 
fineness strength 3.1 cN/dtex 
elongation at break 19% 
initial modulus 43 cN/dtex 
The textile data remain substantially unchanged after the heat treatment. 
EXAMPLE 16 
(Comparison) 
A polyphenylene sulfide produced in accordance with EP-A 171 021, melt 
viscosity 360 Pa.s at 306.degree. C., was spun at 295.degree. C. through a 
die comprising 30 bores 0.5 mm long and 0.25 mm in diameter. 
The die filter consisted of a VA cloth with 16,000 meshes/cm.sup.2. 
The take-off rate was 500/minutes. The spun material was stretched in three 
stages (twice in boiling water and then on a contact heater at 135.degree. 
C.) to a total stretching ratio of 7.1 and was then set under tension for 
1 minute at 260.degree. C. 
The following textile data were obtained: 
Denier 24 dtex 
fineness strength 4.1 cN/dtex 
elongation at break 11% 
initial modulus 55 cN/dtex 
boiling-induced shrinkage &lt;0.2% 
thermal shrinkage 240.degree. C. &lt;0.2% 
A creep test after 1 hour at 240.degree. C. under a load of 0.1 cN/dtex 
produced an elongation of 1%. 
The textile data of the fibers of the two polymers are of the same order. 
However, the thermal stability of the fibers of Example 2 is distinctly 
higher (Tm Example 6.1: 349.degree. C., Tm Example 6.2: 278.degree. C.).