Note: Descriptions are shown in the official language in which they were submitted.
The invention relates to a composition containing a
partially hydrogenated block copolymer comprising at least
two terminal polymer bloc~s A of a monoalkenyl arene having
an average molecular weight of from 5gOOO to 125,000 and
at least one intermediate polymer block ~ of a conjugated
diene ha~ing an average molecular weight of from ~0,000 to
300~000, in which the terminal polymer bloclcs A constitute
from 8 to 55% by weight of the block copolymer and no more
than 25~ of the arene double bonds of the polymer blocks A
and at least 80% Or the aliphatic double bonds of the
polymer blocks B have been reduced by hydrogenation.
Engineering thermoplastic resins are a group of polymers
that possess a balance of properties comprising strength,
stiffness, impact resistance, and long term dimensional
stability that make them useful as structural materials.
Engineering thermoplastic resins are especially attractive
as replacements for metals because of the reduction in
weight that can often be achieved as, for example, in
automotive applications.
For a partlcular application, a single thermoplastic
resin may not offer the combination of properties desired
and, therefore, means to correct this deficiency are of
interest~ One particularly appealing route is through
blending together two or more polymers (which individually
have the properties sought) to give a material with the
desired combination of properties. This approach has been
.
37
;~ .
successful in li~ited cases, such as in the improvement
of impact resistance for thermoplastic resins, e.g.,
polystyreneg polypropylene and poly(vinyl chloride),
using special blending procedures or additives ~or this
purpose. However, in general, blending of thermoplastic
resins has not been a successful route to enable one to
combine into a single material the desirable individual
characteristics of two or more polymers. Instead, it has
often been found that such blending results in combining
the worst features of each with the result being a
material of such poor properties as not to be of any
practical or commercial value. The reasons for this
failure are rather well understood and stem in part from
the fact that thermodynamics teaches that most combinations
of polymer pairs are not miscible, although a number of
notable e~ceptions are known. More importantly, most
polymers adhere poorly to one another. As a result, the
interfaces between component domains (a result o~ their
immiscibility) represent areas o~ severe weakness in blends
and, therefore, provide natural flaws and cracks which
result in facile mechanical failure. Because of this~
mos~ polymer pairs are said to be "incompatible". In some
instances the term compatibility is used synonymously
with miscibility, however, compatibility is used here in
a more general way that describes the ability to combine
two polymers together for beneficial results and may or
may not connote miscibility.
One method which may be used to circumvent this
problem in polymer blends is to "compatibilize" the two
polymers by blending in a third component, orten referred
to as a "compatibi.lizing agent", that possesses a dual
solubility nature for the two polymers to be blended.
Examples of this third component are obtained in block
or graft copolymers. As a result of thi.s characteristic,
this agent locates at the interface between components ~:
and greatly improves interphase adhesion and therefore
increases stability to gross phase separati.on.
The i.nvention covers a means to stabilize multi-
polymer blends that is independent of the prior art : .
compatibilizing process and is not restricted to the
necessity for restrictive dual solubi].ity characteristics.
The materials used for this purpose are special block co-
polymers capable of thermally reversible self-cross-linking.
Their action in the present invention is not that visualize~
by the usual compatibilizing concept as evidenced by the
general ability of these materials to perform similarly
for a wide range of blend components which do not conform
to the solubility requirements Or the previous concept.
Now, the invention provides a composition containing
a partially hydrogenated block copolymer comprising at
least two terminal polymer blocks A of a monoalkenyl arene ~ -
having an average molecular weight of from 5,000 to 125,000,
and at least one intermediate polymer block B of a con-
jugated diene having an average molecular weight of from 10,000 to 300,000,
in which the terminal polymer blocks A constitute from 8 to 55% by weight
of the block copolymer and no more than 25% of the arene double bonds of the
polymer blocks A and a~ least 80% of ~he aliphatic double bonds of the
polymer blocks B ha~e been reduced by hydrogenation, which composition is
characteri~ed in ~hat the composition comprises:
(a) 4 to 40 parts by weight of the partially hydrogenated block copolym0r;
~b) a polycarbonate having a mel~ing point oYer 120C;
~c) 5 to 48 parts by weight of at leas~ one dissimilar engineering thermo-
plastic resin being selected from the group consisting of polyamides,
polyolefins, thermoplastic polyesters, poly(aryl ethers), poly(aryl
sulphones), acetal resins, thermoplastic polyure*hanes, halogenated
thermoplastics, and nitrile resins,
in which the weight ratio of the polycarbonate to the dissimilar engineering
~hermoplastic resin is greater than 1:1 so as to form a polyblend wherein
at least two of the polymers form at least partial continuous interlocked
networks with each other.
In anotheT aspect, the invention p~ovides a process ~or thepreparation of a composition as defined ~bove, charac~eri~ed in that
~0 (a~ 4 to 40 parts by weight of a partially hydrogenated block copolymer
comp~ising at least two terminal polymer blocks A o a monoalkenyl arene
having an average molecular weigh~ of from 5,000 to 125,000, and at
leas~ one intermediate polymer block B of a conjugated diene having an
average molecular weight o from 10,000 to 300,000, in which the
terminal polymer blocks A constitute from 8 to 55% by weight o~ the block
copolymer and no more than 25~ of the arene double bonds of the polymer
blocks A and at leas~ 80% of the aliphatic double bonds of the polymer
blocks B have b~en reduced by hyd~ogenation, are mixed at a processing
temperature Tp of between 150C and 400C with
3a Cb) ~ polycaTbona~e having a melting point over 120C, and
(c) 5 to 48 parts by weight of at least one dissimilar engineering thermo-
plastic resin being selected ~rom the group consisting of polyamides~
3~
polyolefins, thel~oplastic polyesters, poly(aryl ethers), poly~aryl sul-
phones~ acetal resins, thermoplastic polyuTethanes, halogenated thermo-
plastics and nitrile resins,
in ~hich the weight ratio of the polycarbonate to ~he dissimilar engineeTing
thermoplastic resin is greater than 1:1 so as ~o orm a polyblend wherein
at least two of the polymers form at least partial continuous interlock0d
networks with each other.
The block copolymer of ~he invention effectively acts as a
mechanical or structural stabilizer which interlocks
,
the various polymer structure networks and prevents the
consequent separation of the polymers during processing
and their subsequent use. As defined more fully herein-
after, the resulting structure of the polyblend (short
for "polymer blend") is that of at least two partial
continuous interlocking networks. This interlocked
structure results in a dimensionally stable polyblend
that will not delaminate upon extrusion and subsequent
use.
To produce stable blends it is necessary that at
least two of the polymers have at least partial continuous
networks which interlock with each other. Preferably, the
block copolymer and at least one other polymer have partial
continuous interlocking network structures. In an ideal
situation all of the pol~mers would have complete con-
tinuous networks which interlock with each other. A ~ -
partial continuous network means that a portion of the
polymer has a continuous network phase structure while
the other portion has a disperse phase structure. Prefer-
ably/ a major proportion (greater than 50% by weight) of
the partial continuous network is continuous. As can be
readily seen, a large variety of blend structures is
possible since the structure of the polymer in the blend
may be completely continuous, completely disperse, or
partially continuous and partially disperse. ~urther yet,
the disperse phase Or one polymer may be dispersed in a
- 7 - ~ 37
second polymer and not in a third polymer. To illustrate
some of the structures, the following lists the various
combinations of polymer structures possible where all
structures are complete as opposed to partial structures.
Three polymers (A, B and C) are involved. The subscript
"c" signifies a continuous structure while the subscript
"d7' signifies a disperse structure. Thus, the designation
''ACB'' means that polymer A is continuous with polymer B,
and the designation "BdC'~ means that polymer B is disperse
in polymer C, etc.
AcB AcC BCC
AdB AcC BcC
AcB AcC BdC
BdA AcC BcC
BdC AcB ACC
CdA AcB ACC
CdB AcB ACC
Through practice of the invention, it is possible to
-7a-
improve one type of physical property of the composite
blend while not causing a significant deterioration in
another physical property. In the past this has not
always been possible. For example, in the past it was
expected that by adding an amorphous rubber such as an
ethylene-propylene rubber to a thermoplastic polymer
to improve impact strength, one would necessarily obtain a
composite blend having a significantly reduced heat
distortion temperature (HDT). This results from the fact
that the amorphous rubber forms discrete particles in
the composite and the rubber, almost by definition, has
an exceedingly low HDT, around room temperature. How-
ever, in the present invention it is possible to
significantly improve impact strength while not de-
tracting from the distortion temperature. Even more
surprising, as shown in the illus-trative Examples that
follow, in some cases the heat distortion temperature
surprisingly increases as the amount of the subject block
copolymers is increased, which phenomer.onis totally un-
expected from what one skilled in the art would expect.
This ability to tailor-make polymer blends in order
to arrive at a much improved balance of properties has
not been taught in the pri~or art.
It is particularly surprising that even just small
amounts of the block copolymer are sufficient to stabilize
the structure of the polymer blend over very wide relative
concentrations. For example, as little as four parts by
weight of the block copolymer is sufficient to stabilize
a blend of 5 to 90 parts by weight polycarbonate with 90 to
5 parts by wei~ht of a dissimilar engineering thermoplastic.
In addition, it is also surprising that the block co-
polymers are userul in stabilizing polymers of such a wide ; ~-
variety and chemical make-up. As explained more fully
hereinafter, the block copolymers have this ability to `~
stabilize a wide variety of polymer over a wide range of
concentrations since they are oxidatively stable, possess
essentially an infinite viscosity at zero shear stress~
and retain network or domain structure in the melt.
Another significant aspect of the invention is that
the ease of processing and forming the various polyblends
is greatly improved by employing the block copolymers as
stabilizers. ~ `
The block copolymers employed in the composition
according to the invention may have a variety of geometrical ~ `
structure, since the invention does not depend on any
specific geometrlcal structure, but rather upon the
chemical constitution of each of the polymer blocks. Thus,
the block copolymers may be linear, radial or branched.
Methods for the preparation of such polymers are known in
the art. The structure of ~he polymers is determined by
their methods of polymerization. For example, linear
polymers result by sequentia:L introduction of the
desired monomers into the reaction vessel when using
such initiators as lithium-alkyls or dilithio-stilbenea
or by coupling a two-segment block copolymer with a
difunctional coupling agent. Branched structures,on the
other hand, may be obtained by the use of suitable
coupling agents having a functionality with respect to
the precursor polymers of three or more. Coupling may be
effected with multifunctional coupling agents, such as
dihaloalkanes or -alkenes and divinyl benzene as well as
certain polar compounds, such as silicon halides, siloxanes
or esters of monohydric alcohols with carboxylic acids.
The presence of any coupling residues in the polymer may -
be ignored for an adequate description of the polymers
forming a part of the compositions of this invention.
Likewise, in the generic sense, the specific structures
also may-be ignored. The invention applies especi~lly
to the use of selectively hydrogenated polymers having
the configuration before hydrogenation Or the following
typical species:
polystyrene-polybutadiene-polystyrene (SBS)
polystyrene-polyisoprene-polystyrene (SIS)
poly(alpha-methylstyrene)polybutadiene-
poly(alpha-methylstyrene) and
--10--
poly(alpha-methylstyrene)polyisoprene-
poly(alpha-methylstyrene). ~ ,
Both polymer blocks A and B may be either homopolymer
or random copolymer blocks as long as each polyMer block
predominates in at least one class Or the monomers charac~
terizing the polymer blocks. The polymer block A may '
comprise homopolymers of a monoalkenyl arene and co-
polymers of a monoalkenyl arene with a conjugated diene
as long as the polymer blocks A individually predominate ,~ -
in monoalkenyl arene units. The term "monoalkenyl arene"
will be taken to include especially styrene and its '
analogues and homologues including alpha-methylstyrene
and ring-substituted styrenes, particularly ring-rnethyl~
ated styrenes. The preferred monoalkenyl arenes are
styrene and alpha-methylstyrene, and styrene is
particularly preferred. The polymer blocks B may comprise '~
homopolymer~ of a conjugated diene, such as butadiene or
isoprene J and copolymers of a conjugated diene with a
monoalkenyl arene as long as the polymer blocks B pre- -
dominate in conjugated diene units. When the monomer
employed is butadiene, it is preferred that between 35
and 55 mol. per cent of the condensed butadiene units in
the butadiene polymer block have 1,2-configuration. Thus,
when such a block is hydrogenated, the resulting product
is, or resembles, a regular copolymer block of ethylene
and butene-1 (EB). If the conjugated diene employed is
~ - ~ ~
37
--11--
isoprene, the resulting hydrogenated product is or
resembles a regular copolymer block of ethylene and
propylene (EP).
Hydrogenation of the precursor block copolymers is
preferably effected by use of a catalyst comprising the
reaction products of an aluminium alkYl compound with
nickel or cobalt carboxylates or alkoxides under such
conditions as to substantially completely hydrogenate
at least ~0% of the aliphatic double bonds, while
hydrogenating no more than 25% of the alkenyl arene
aromatic double bonds. Preferred block copolyrners are - -
those where at least 99% of the aliphatic double bonds
are hydrogenated while less than 5% of the aromatic
double bonds are hydrogenated.
The average molecular weights of the individual
blocks may vary within certain limits. The block co-
polyrner present in the composit:ion according to the
invention has at least two terminal polymer blocks A of
a monoalkenyl arene having a number average molecular
weight of from 5,000 to 125,000g preferably from 7,000
to 60,000, and at least one intermediate polyrner block B
of a conjugated diene having a nurnber average molecular ~;
weight of from 10,000 to 300,000, preferably from 30,000
to 150~000. These molecular weights are most accurately
determined by tritium counting methods or osmotic pressure
measurements. -
12-
The proportion of the polymer blocks A of the mono-
alkenyl arene should be between 8 and 55% by weight of
the block copolymer, preferab]y between 10 and 30% by ;
weight.
The polycarbonates present in the compositions ac-
cording to the invention are of the general formulae~
O
(Ar - A Ar - O C - )n- I : :
and
~Ar- -O C ~n II ~
~' :-
wherein Ar represents a phenylene or an alkyl, alkoxy,halogen or nitr~ubstituted phenylene group; A represents
a carbon-to-carbon bond or an alkylidene, cycloalkylidene, ~ -
alkylene, cycloalkylene, a~o, imino, sulphur, oxygen,
sulphoxide or sulphone group, and n is at least two.
...
-13-
The preparation oI` the polycarbonates is well known.
A preferred method of preparation is based on the reaction
carried out by dissolving the dihydroxy component in a
base, such as pyr;dine and bubbling phosgene into the
stirred solution at the desired rate. Tertiary amines may
be used to catal~ze the reaction as well as to act as acid `~
acceptors throughout the reaction. Since the reaction is
normally exothermic, the rate of phosgene addition can be
used to control the reaction temperature. The reactions
generally utilize equimolar amounts Or phosgene and (li-
hydroxy reactants, however, the molar ratios can be v~ricd
dependent upon the reaction conditions.
In the formulae I and II mentioned, Ar and l~ are,
preferablyg p-phenylene and isopropylidene, respectively.
This polycarbonate is prepared by reacting para,para'iso~
propylidenediphenol with phosgene and is sold under the
trade mark LEXAN ~ and under the trade mark ME~LON ~
This commercial polycarbonate has a molecular weight Or ~ .
around 18,000, and a melt temperature of over 230C.
Other polycarbonates may be prepared by reacting other
dihydroxy compounds, or mixtures of dihydroxy compounds,
with phosgene. The dihydroxy compounds may include aliphatic
dihydroxy compounds although for best high temperature
properties aromatic rings are essential. The dihydroxy
compounds may include within the structure diurethane ;
linkages. Also, part o~ the structure may be replaced by
siloxane linkage.
~T~ 2~B7
The term "dissimilar engineerir-g thermoplastic resin"
ref'ers to engineering l;herrnoplastic resins different from
those encompassed by the polycarbonates present in the
compositions according to the invention.
The term "engineering thermoplastic resin" encompasses
the various polymers found in the classes listed in Table A
below and thereaf`ter defined in the specification.
TABLE _
1. Polyolefins
2. Thermoplastic polyesters
3. Poly(aryl ethers) and poly(aryl sulphones)
4. Polyamides
5. Qcetal resins
6. Thermoplastic polyurethanes
7- Halogenated thermoplastics
8. Nitrile resins
Preferably these engineering thermoplastic resins
have glass transition temperaturesor apparent crystalline
melting points (defined as that temperature at which the
modulus, at low stress, shows a catastrophic drop) of
over 120C, preferably betT~een 150C and 350C, and are
capable of ~orming a continuous network structure
through a thermally reverslble cross-linking mechanism.
Such thermally reversible cross-linking mechanisms in-
clude crystallites, polar aggregations, ionic aggregations,
lamellae, or hydrogen bonding. In a specific embodiment,
- 1 5- ~ 237
where the viscosity ofthe block copolymer or blended
block copolymer composition at processing temperature Tp
and a shear rate of 100 s 1 is n, the ratio of the
viscosity of the engineering thermoplastic resins, or
blend of engineering thermoplastic resin with viscosity
modifiers to n may be between 0.2 and 4.0, preferably 0.8
and 1.2. As used in the specification and claims, the
viscosity of the block copolymer, polycarbonate and the
thermoplastic engineering resin is the "melt viscosity"
obtained by employing a piston-driven capillary melt
rheometer at constant shear rate and at some consistent
temperature above melting, say 260C. The upper limit
(350C) on apparent crystalline melting point or glass
transition temperature is set so that the resin may be
processed in low to medium shear rate equipment at com-
mercial temperature levels of 350C or less. ;
The engineering thermoplastic resin includes also
blends of various engineering thermoplastic resins and
blends with additional viscosity modifying resins.
~hese various classes of engineering thermoplastics
are defined below.
The polyolefins, if present in the composition ac- -
cording to the invention are crystalline or crystallizable.
They may be homopolymers or copolymers and may be~derived
from an alpha-olefin or 1-olefin having 2 to 5 carbon
atoms. Examples of particular useful polyolefirsinclude
-16-
~ 3~
low-density polyethylene, high-density polyethylene~ iso-
tactic polypropylene, poly(1-butene), poly(4-methyl-1-
pentene), and copolymers of 4 methyl-1-pentene with
linear or branched alpha-olefins. A crystalline or
crystallizable structure is important in order for the
polymer to be capable of forming a continuous structure
with the other polymers in the po]ymer blend according
to the invention. The nurnber average molecular weight of
the polyolefinsmay be above 10,000, preferably above
50,000. In addition, the apparent crystalline melting
point may be above iOOC, preferably between iOOC and
250C, and more preferably between 140C and 250C.
The preparation of these various polyolefins are well
known. See generally "Olefin Polymers", Volume 14, Kirk-
Othmer Encyclopedia of Chemical Technology, pages
217-335 (1967).
When a high-density polyethylene is employed, it has
an approximate crystallinity of over 75% and a density in
\
2~
kilograms per litre (kg/1) of between 0.94 and 1.0 while
when a low density polyethylene is employed, it has an
approximate crystallinity of over 35% and a density o~
between 0.90 kg/1 and 0.94 kg/1. The composition ac-
cording to the invention may contain a polyethylene havinga number average molecular weight of 50,000 to 5007000.
When a polypropylene is employed, it is the so- -
called isotactic polypropylene as opposed to atactic
polypropylene. The number average molecular weight Or the
polypropylcne employedmaYbeineXcess of 100,000. The poly-
propylene rnay be prepared using methocls of the prior
art. Depending on the specific catalyst and polymer- -
ization conditions employed, the polymer produced may
contain atactic as well as isotactic, syndiotactic or
so-called stereo-block molecules. These may be separated
by selective solvent extraction to yield products of
low atactic content that crystalli~e more completely.
The preferred commercial polypropylenes are generally
prepared uslng a solid, crystalline, hydrocarbon-in-
soluble catalyst made from a titanium trichloride com~position and an aluminium alkyl compound, e.g., tri-
ethyl aluminium or diethyl aluminium chloride. If
desired, the polypropylene employed is a copolymer
containing minor (1 to 20 per cent by weight) amounts
of ethylene or another alpha-ole~in as comonomer.
2~7
., ,
-18-
The poly(1-butene) preferably has an isotactic structure.
The catalysts used in preparing the poly(1-butene) are
preferably organo~metallic compounds commonly referred to
as Ziegler-Natta catalysts. A typical cata]yst is the
interacted product resulting from mixing equimolar quan-
tities of titanium tetrachloride and triethylaluminium.
The manu~acturing process is normally carried out in an
inert diluent such as hexane. Manufacturing operations,
in all phases of po:Lymer formation, are conducted in such
a manner as to guarantee rigorous exclusion Or water even
in trace amounts.
One very suitable polyolefin is poly(4-methyl-1-pentene).
Poly(4-methyl-1-pentene) has an apparent crystalline melt-
ing point of between 240 and 250 C and a relative density
f between 0.80 and 0.85. Monomeric 4-methyl-1-pentene is
commercially manufactured by the alkali-metal catalyzed
dimerization of propylene. ~he homopolyrnerization o~
4-methyl-1-pentene with Ziegler-Natta catalysts is described
in the Kirk~Othmer Enclopedia of ~hemical Technology,
Supplement volume, pages 789-792 (second edition, 1971).
However, the isotactic homopolymer of 4-methyl-1-pentene
has certain technical defec-ts, such as brittleness and
inadequate transparency. Therefore, commercially available
poly(4-methyl-1-pentene) is actually a copolymer with
minor proportions of other alpha-olefins, together with
the addition of suitable oxidation and melt stabilizer
- - 1 9 - ~ ~7
systems. These copolymers are described in the Kirk-
Othmer Encyclopedia of Chemical Technology, Supplement
volume, pages 792-907 (second edition, 1971), and are
~ available under the trade ~me TPX ~ resin. Typical
alpha-olefins are linear alpha-olefins having from 4
to 18 carbon atoms. Suitable resins are copolymers of
4-methyl-1-pentene with from 0.5 to 30% by weight of a
linear alpha-olefin.
If desired, the polyolefin is a mixture of various
polyolefins. However, the much preferred polyolefin is
isotactic polypropylene.
The thermoplastic polyesters,if present in the com-
positions according to the invention, have a generally
crystalline structure, a melting point over 120C, and
are thermoplastic as opposed to thermosetting.
\\ ;~
-20-
One particularly useful group of polyesters are those
thermoplastic polyesters prepared by condensing a di-
carboxylic acid or the lower alkyl ester, acid halide,
or anhydride derivatives thereof with a glycol, according
~ 5 to methods well known in the art.
Among the aromatic and aliphatic dicarboxylic acids
suitable for preparing polyesters are oxalic acid, malonic
acid, succinic acid, glutaric acid, adipic acid, suberic
acid, azelaic acid, sebacic acid, terephthalic acid, iso-
phthalic acid, p-carboxyphenoacetic acid, p,p'~isarboxydiphe-nyl,
p,p'-dicarboxydiphenylsulphone, p-carboxyphenoxyacetic acid,
p-carboxyphenoxypropionic acid, p-carboxyphenoxybutyric acid,
p-carboxyphenoxyvaleric acid, p-carboxyphenoxyhexanoic ac~d,
p,p'-dicarboxydiphenylmethane, p,p-dicarboxydiphenylpropane,
p,p'-dicarboxydiphenyloctane, 3-alkyl-4-(~-carboxyethoxy)-
ben~oic acid, 2~6-naphthalene dicarboxylic acid, and 2~7-
naphthalene dicarboxylic acid. Mixtures of dicarboxylic
acids can also be employed. Terephthalic acid is particularly
preferred.
The glycols suitable for preparing the polyesters
include straight-chain al~ylene glycols of 2 to 12 carbon
atoms, such as ethylene glycol, lg3-propylene glycol,
1,6-hexylene glycol, 1,10-decamethylene glycol, and 1,12-
dodecamethylene glycol. Aromatic glycols can be substituted
in whole or in part. Suitable aromatic dihydroxy compounds
include p-xylylene ~lycol, pyrocatechol, resorcinol,
%3~
hydroquinone, or alkyl-substituted derivatives of these
compounds. Another suitable glycol is 1,4-cyclohexane
dimethanol. Much preferred glycols are ~e straight-chain
alkylene glycols having 2 to 4 carbon atoms.
A preferred group of polyesters are poly(ethylene
terephthalate), poly(propylene terephthalate), and poly-
(butylene terephthalate). A much preferred polyester is
poly(butylene terephthalate). Poly(b~tylene terephthalate),
a crystalline copolymer, may be rormed by the polycondensation
of 1,4~butanediol and dimethyl terephthalate or terephthalic
acid, and has the generalized formula:
C_o ~-~to-~
n
where n varies from 70 to 140. The average molecular weight
of the poly(butylene terephthalate) preferab]y varies from
20,000 t~ 25,000.
Commercially available poly(butylene terephthalate) is
B~ available under the trade ~*m~ VALOX ~ thermoplastic
polyester. Other commercial polymers include CELANEX
TENITE ~ and VITUF ~ .
Other useful polyesters include the cellulosic esters.
The thermoplastic cellulosic esters employed herein are
widely used as moulding, coating and film-forming materials
-2~
and are well known. These materials include the solid
thermoplastic forms of cellulose nitrate, cellulose
acetate (e.g., cellulose diacetate, cellulose tri-
acetate), cellu1ose butyrate, cellulose acetate butyrate,
cellulose propionate, cellulose tridecanoate, carboxy-
methyl cellulose, ethyl cellulose, hydroxyethyl cellulose
and acetylated hydro~yethyl cellulose as described on
pages 25-28 of Modern Plastics Encyclopedia~ 19~1-72, and
references listed there;n.
Another userul polyester is a polyp;valolactone. Poly-
pivalolactone is a linear polymer having recurring ester
structural units mainly Or the formula:
CH2 - C(C~3-)2 ~ C(0)0
i.e., units derived from pivalolactone. Preferably, the poly-
ester is a pivalolactone homopolymer. Also included, however~are the copolymers Or pivalolactone wlth no rnore tharl 50 mol.~,
preferably not more than ~0 mol.% of another beta-propio-
lactone, such as beta-propiolactone, alpha,alpha-diethyl-
beta-propiolactone and alpha-methyl-alpha-ethyl-beta-propio-
lactone. The term "beta-propiolactones" re~ers to beta-
propiolactone (2-oxetanone) and to derivatives thereof which
carry no substituents at the beta-carbon atom of the lactone
ring. Preferred beta-propiolactones are those containing a
tertiary or quaternary carbon atom in the alpha-position
relative to the carbonyl group. Especially preferred are the
alpha,alpha-dialkyl-beta-propiolactones wherein each Or the
alkyl groups independently has from one to four carbon atoms.
32~
-23~
Examples Or useful monomers are:
alpha-ethyl-alpha-methyl-beta-propiolactone,
alpha-methyl-alpha-isopropyl-beta-propiolactone,
alpha-ethyl-alpha-n-butyl-beta-propiolactone,
alpha-chloromethyl-alpha-methyl-beta-prop:iolactone,
alpha~alpha-bis(chloromethyl~-beta-propiolactone, and
alpha,alpha-dimethyl-beta-propiolactone (pivalolactone). ~ ;
These polypivalolactones have an average molecular weight in
excess of 20,000 and a melting point in excess of 120C.
Another useful polyester is a polycaprolactone.
Preferred poly(~-caprolactones) are substantially linear
polymers in which the repeating unit is:
rO_ ol ~:
t c~l2 c~l2 cll2_cH2 CH2 c~
These polymers have similar properties to the polypivalo-
lactones and may be prepared by a similar polymerization
mechanism.
Various polyaryl polyethers are also useful as engineer-
ing thermoplastic resins. The poly(aryl polyethers) which
may be present in the composition according to the invention
include the linear thermoplastic polymers composed Or re-
curring units having the formula:
(0 G 0 - G' ~ - I
wherein Gisthe residuum of a dihydric phenol selected from
the group consisting Or:
-24-
~ 3_ II
,
and
~; ~ R ~
wherein R represents a bond between aromati.c carbon atoms,
__ O ~ S - , S- s-,or -l divalent hydrocarbon radica].
having from 1 to 18 carbon atoms i,nclusive, and G' i.s the
residuum Or a dibromo or di-i.odobenzenoid compound
selected f'rom the group consistin~ Or:
~ IV
and
- ~ ~ R \73 v
wherein R' represents a bond between aromatic carbon atoms,
-O , - S g - S S - ,or a divalent hydrocarbon
rad~cal having ~rom 1 to 18 carbon atoms inclusive, with
the provisions that when R is O - -, R' is other than
O ; when R' is O , R is other than -O - ;
when G is II, G' is V, and when G' is IV, G is III.
-25-
Polyarylene polyethers Or this type exhibit excellent physical
properties as well as excellent thermal oxidative and
chemical stability. Commercial poly(aryl polyethers) are
available under the trade ~e ARYLON T ~ Polyaryl ethers,
having a melt temperature of between 280C and 310C.
Another group Or useful engineering thermoplastic
resins include aromatic poly(sulphones) comprising re-
peating units of the formula: -
.
- -Ar S02 - ~
in which Ar i.s a bivalent aroma~ic radical and may vary ~ ~ ,
from unit to unit in the polymer chain (so as to f`orm co-
polymers of various kinds). Thermoplastic poly(sulphones)
~enerally have at least some units of the structure:
,~3-z~
SO2 `
in which Z is oxygen or sulphur or the residue of an
aromatic diOlg such as a 4,~'-bisphenol. One example of
such a poly(sulphone) has repeating units Or the formula:
~ O ~--S02~
-26-
another has repeating units of the formula:
~_s~ so2--
and others have repeating units of the formula:
~ S02 ~ _ O ~C~/3~o
- CH3
or copolymerized units in various proportions of the
formula: ~-
SO2
and
~_o~3-so2- ~ ~ ~
The thermoplastic poly(sulphones) may also have repeatlng ~: :
units having the formula: ~
_~_o~3-S2-- ~
Poly(ether sulphones) having repeating units of the
following structure:
-27-
t~ ~ s02~
and poly(ether sulpholles) having repeating units of the
following structure:
52 ~ ' ~ C ~ ~n
are also useful as engineering thermoplastic resins.
By polyamide is meant a condensation product which
contains recurring aromatic and/or aliphatic amide groups ~
as integral parts of the main polymer chain, such products ~ ;
being known generically as "nylons". A polyamide may be
obtained by polymerizing a mono-aminomonocarboxylic acid
or an internal lactam thereof having at least two carbon
atoms between the amino and carboxylic acid groups; or
by polymerizing substantially equimolar proportions of a
diamine which contains at least two carbon atoms between ~ ~
the amino groups and a dicarboxylic acid; or by polymer- ;
i~ing a mono-aminocarboxylic acid or an internal lactam
thereof as defined above together with substantially equi-
molar proportions of a diamine and a dicarboxylic acid.
The dicarboxylic acid may be used in the form of a functional ~-
derivative thereof, for example an ester.
-28~ 8 ~ 3~
The term "substantially equimolecular proportions"
(of the diamine and of the dicarboxylic acid) is used to
co~er both strict equimolecular proportions and the slight
departures therefrom which are involved in conventional
8~23~
-29-
techniques for stabilizing the viscosity of the resultant
polyamides.
As examples of the sa:id mono-aminomonocarboxylic acids
or lactams thereof there may be mentloned those compounds
containing from 2 ~o 16 carbon atoms be-tween the amino an~
carboxylic acid groups, said carbon atoms forming a ring
with the - -CO.N~I group in the case of a lactam. As
particular examples of aminocarboxylic acids and lactams
there may be mentioned ~-aminocaproic acid, butyrolactam,
pivalolactam, caprolactam, capryl-lactam, enantholactam,
undecanolactam, dodecanolactam and 3- and 4-amino benzoic
acids.
Examples of the said diamines are diamines of the
general formula H2N(CH2)nNH2, wherein n is an integer of
from 2 to 16, such as trimethylenediamine~ tetramethylene- ~ -
diamine, pentamethylenediamine, octamethylenediamine,
decamethylenediamineg dodecamethylenediamine, hexadeca- ;
methylenediamine, and especially hexamethylenediamine.
C-alkylated diamines, e.g.s 2,2-dimethylpentamethylene-
diamine and 2,2,4-and 2,4,4-trimethylhexamethylenediamine
are further examples. Other diamines which may be mentioned
as examples are aromatic diamines, e.g., p-phenylene~
diami.ne, 4,4'-diaminodiphenyl sulphone~ 4,4'-diaminodi-
phenyl ether and 4,LI t -diaminodiphenyl sulphone, 4,4'-di-
aminodiphenyl ether and 4~4'-diaminodipilenylmethane; and
cycloaliphatic diamines, for example diaminodicyclohexyl-
methane.
~ 37
-30-
The said dicarboxylic acids may be aromatic, ror
example isophthali.c and terephthalic acids. Preferred
dicarboxylic acids are of the formula l-IOOC.Y.COOH,
wherein Y represents a divalent aliphatic radical
containing at least 2 carbon atoms, and examples of
such acids are sebacic acid, octadecanedioicacid,
suberic acid, azelaic aci.d, undecanedioic acid, ~lutaric
acid, pimelic acid, and especially adipic acid. Oxalic
acid is also a prererred acid.
Speci~ically the following polyamides may be in-
corporated in the thermoplastic polymer blends of the
invention:
polyhexamethylene adipamide (nylon 6:6)
polypyrrolidone (nylon 4)
polycaprolactam (nylon 6)
polyheptolactam (nylon 7)
polycapryllactam (nylon 8)
polynonanolactam (nylon 9)
poly~ndecanolactam (nyIon 11)
polydodecanolactam (nylon 12)
polyhexamethylene azelaiamide (nylon 6:9)
polyhexamethylene sebacamide (nylon 6:10)
polyhexamethylene isophthalamide (nylon 6:iP)
polymetaxyly].ene~ipamide (nylon MXD:6)
polyamide o~ hexamethylene diarnine and n~dodecanedioic
acid (nylon 6:12)
~ ~ ~9~3~37
polyamide of dodecamethylenediamine and
n-dodecanedioic acid (nylon 12:12).
Nylon copolymers may also be used, for example co-
polymers of the following:
hexamethylene adipamide/caprolactam (nylon 6:6/6)
hexamethylene adipamide/hexamethylene-isophthalamide
(nylon 6:6/6ip)
hexamethylene adipamide/hexamethylene-terephthalamide
(nylon 6:6/6T)
trimethylhexamethylene oxamide/hexamethylene oxamide ~
(nylon trimethyl-6:2/6:2) ~ ~.
hexamethylene adipamide/hexamethylene-azelaiamide ~
(nylon 6:6~6:9) ~ :
hexamethylene adipamide/hexamethylene-azelaiamide/ ~ -~
caprolactam (nylon 6:6/6:9/6).
Also useful is nylon 6:3. This polyamide is the product :~
of the dimethyl ester of terephthalic acid and a mixture of
isomeric trimethyl hexamethylenediamine.
Preferred nylons include nylon 6,6/6, 11, 12, 6/3
and 6/12.
The number average molecular weights of the polyamldes
may be above 10,000.
3~
-32-
The acetal resins which may be present in the com-
positions according to the invention include the high
molecular weight E)olyacetal homopolymers made by polymer-
izing formaldehyde or trioxane. These polyacetal homo-
~,y .
polymers are commercia]1y available under the trade ~_
DELRIN ~. A related polyether-type resin is available
under the trade ~ PENTON~_J and has the structure:
_.
C~12Cl ' ' :
_ _o - C~l2 - ~ Cl~2- _
C'~l2Cl
n
The acetal resin prepared from rormaldehyde has a high
molecular weight and a structure typified by the following:
- H- O ( CH2- O- CH2-0) H
where terminal groups are derived from controlled amounts of
water and the x de\lotes a large (preferably 1500) number of
formaldehyde units linked in head-to~tail fashion. To in-
crease thermal a~d chemical resistance, terminal groups
are typically converted to esters or ethers.
Also included in the term polyacetal resins are the
polyacetal copolymers. These copolymers lnclude block co-
polymers of formaldehyde with monomers or prepolymers
other materials capable of providing active hydrogens,
~ 7
-33- ~`
such as alkylene glycols, polythiols, vinyl acetate-
acrylic acid copolymers, or reduced butadiene/acrylonitrile
polymers.
Celanese has commercially available a copolymer Or
formaldehyde and ethylene oxide under the trade ~ CELCON
that is userul in the blends of the present invention. These
copolymers typically have a structure comprising recurrin~ -
units having the formula: ~ ~
, ~ "
. _
~ H I ~
wherein each R1 and R2 is selected from the group consisting
Of hydrogen, lower alkyl and lower halogen substituted
alkyl radicals and wherein n is an integer from zero to three
and wherein n is zero in from ~5% to 99.9% of the recurring
units.
Formaldehyde and trioxane can be copolymerized with
other aldehydes, cyclic ethers, vinyl compounds, ketenes,
cyclic carbonates, epoxides~ isocyanates and ethers. T~hese
compounds include ethylene oxide, 1,3-dioxolane, 1,3-dioxane,
1,3-dioxepene, epichlorohydrin, propylene oxide, isobutylene
oxide, and styrene oxide.
-3L~ 7
Polyurethanes, otherwise known as isocyanate resins,
also can be employed as engineering thermoplastic resin as
long as they are thermoplastic as opposed to thermosetting.
For example, polyurethanes formed from toluene di-iso-
cyanate (TDI) or diphenyl methane 4,4-di-isocyanate (MDI)
and a wide range of polyolsg such as polyoxyethylene glycol,
polyoxypropylene glycol, hydroxy-terminated polyesters, poly-
oxyethylene-oxypropylene glycols are suitable.
These thermoplastic polyurethanes are available under
the trade ~ Q-THANE ~ and under the trade ~ffle PE~LETHANE
CPR.
Another group of useful engineering thermoplastics in-
clude those halogenated thermoplastics having an essentially
crystalline structure and a melt point in excess of 120C.
These halogenated thermoplastics include homopolymers and
copolymers derived from tetrafluoroethylene, chlorotrifluoro-
ethylene, bromotrifluoroethylene, vinylidene fluoride, and
vinylidene chloride.
Polytetrafluoroethylene (PTFE) is the name given to
fully fluorinated polymers o~ the basic chemical formula
(CF2 CF2)n which contain 76% by weight fluorine.
Ibe~ h,~l / crystalline and have a crystall ine
237
melting point of` over 300 C. Commercial PTI~E is available
L~ under the trade-r~e TEFLON~ and under the trade-~*~-
FLUON ~ . Polychlorotrifluoroethylene (PCTL~IE) ancl poly-
bromotrifluoroethylene (PBTFE) are also available in high
molecular weights and can be employed in the present in-
vention.
Especially preferred halogenated polymers are homo-
polymers and copolymers Or vinylidene fluoride. Poly-
(vinylidene fluoride) homopolymers are the partially
fluorinated polymers of the chemical formula -~-CH2 - C~2 ~ .
These polymers are tough linear polymers with a crystalline
melting point at 170 C. Commercial homopolymer is available
under the trade ~e KYNAR ~ The term "poly(vinylidene
fluoride)" as used herein refers not only to the normally
solid homopolymers of vlnylidene fluoride, but also to the
normally solid copolymers of vinylidene fluoride containing
at least 50 mol.% of polymerized vinylidene fluoride units,
preferably at least 70 mol.% vinylidene fluoride and more
preferably at least 90 mol.%. Suitable comonomers are
halogenated olefins containing up to 4 carbon atoms, for
example5 sym. dichlorodifluoroethylene, vinyl fluoride,
vinyl chloride, vinylidene chloride, perfluoropropene,per-
fluorobutadiene, chlorotrifluoroethylene, trichloroethylene
and tetrafluoroethylene.
Another useful group of halogenated thermoplastics
include homopolymers and copolymers derived from vinylidene
chloride. Crystalline vinylidene chloride copolyrners are
~36-
especially preferred. The normally crystaJline vinylidene
chloride copolymers that are useful in the present in-
vention are those containing at least 70% by weight Or
vinylidene chloride together with 30% or less of a co-
polymerizable monoethylenic monomer. Exemplary Or suchmonomers are vinyl chloride, vinyl acetate, vinyl
propionate, acrylonitrile, alkyl and aralkyl acrylates
havir.g alkyl and aralkyl groups of up to about ~ carbon ;~
atoms~ acrylic acid~ acrylamide, vinyl alkyl ethers,
vinyl alkyl ketones, acrolein, allyl ethers and others,
butadiene and chloropropene. Know~l terndry composit~on
also may be employed advantageously. Represcntative of
such polymers are those composed of at least 70% by weight
of vinylidene chloride with the remainder madé up of, for
example, acrolein and vinyl chloride, acrylic acid and ;
acrylonitrile, alkyl acrylates and alkyl methacrylates,
acrylonitrile and butadiene, acrylonitrile and itaconic
acid, acrylonitrile and vinyl acetate~ vinyl propionate
or vinyl chloride, allyl esters or ethers and vinyl
chloride, butadiene and vinyl acetate, vinyl propionate,
or vinyl chlor`ide and vinyl ethers and vinyl chloride.
Quaternary polymers of similar monomeric composition will
also be known. Particularly useful for the purposes
the present invention are copolymers of from 70 to 95% by
weight vinylidene chloride with the balance being vinyl
chloride. Such copolymers may contain conventional amounts
-37-
and types of plasticizers, stabilizers, nucleators and
extrusion aids. ~urther, blends of two or more of such
normally crystalline vinylidene chloride po]ymers may
be used as well as blencls comprising such normally
crys-talline polymers in combination with other polymeric
modifiers, e.g., the copolymers of ethylene-vinyl acetate,
styrene-maleic anhydride, styrene-acrylonitrile and poly-
ethylene.
The nitrile resins useful as engineering thermoplastic
resin are those thermoplastic materials having an alpha,b~ta-
olefinically unsaturated mononitrile content of 50% by
weight or greater. These nitrile resins may be homopolymers,
copolymers, grafts of copolymers onto a rubbery substrate,
or blends of homopolymers and/or copolymers.
The alpha,beta-olefinically unsaturated mononitriles
encompassed herein have the structure
Cl~2 C CN
R
where R is hydrogen, an alkyl group having from 1 to 4
carbon atoms, or a halogen. Such compounds include acrylo-
nitrile, alpha-bromoacrylonitrile, alpha-fluoroacrylo-
nitrile, methacrylonitrile and ethacrylonitrile. The mostpreferred olefinically unsaturated nitriles are acrylo-
nitrile and methacrylonitrile and mixtures thereof.
These nitrile resins may be divided into several
classes on the basis of complexity. The simplest molecular
~ 3 7
-3~-
structure is a random copolymer, predominantly acrylonitrile
or methacrylonitrile. The most common example is a
styrene-acrylonitrile copolymer. Block copolymers of
acrylonitrile, in which long segments of polyacrylonitrile
alternate with segments of polystyrene, or of polymethyl
methacrylate, are also known.
Simultaneous polymerization of more than two co-
monomers produces an interpolymer, or in the case of
three components, a terpolymer. A large number of co-
monomers are known. These include alpha-olefins of ~rom
2 to 8 carbon atoms, e.g., ethylene, propylene, iso-
butylene, butene-13 pentene-1, and their halogen and
aliphatic substituted derivatives as represented by vinyl
chloride and vinylidene chloride; monovinylidene aromatic
hydrocarbon monomers o~ the general ~ormula: ;
C - -C
R2
wherein R1 is hydrogen, chlorine or methyl and R2 is an
aromakic radical of 6 to 10 carbon atoms which may also
contain substituentsg such as halogen and alkyl groups
attached to the aromatic nucleus, e.~., styrene~ alpha-
methyl styrene, vinyl toluene, alpha-chlorostyrene, ortho-
chlorostyrene, para-chlorostyrene, meta-chlorostyrene,
ortho-methyl styrene, para-methyl styren~e, ethyl styrene,
2~7
-39-
isopropyl styrene, dichlorostyrene and vinyl naphthalene.
Especially preferred comonomers are isobutylene and styrene.
Another group of comonomers are vinyl ester monomers
of the general formula:
H
R-~C=C
C=O ;~
R3
wherein R3 i~ selected from the group comprising hydrogen,
alkyl groups of rrom 1 to 10 carbon atoms, aryl groups of
from 6 to 10 carbon atoms including the carbon atoms in ~-
ring-substituted alkyl substituents; e.g., vinyl formate~
vinyl acetate, vinyl propionate and v:inyl benzoate.
Similar to the foregoing and also useful are the
vinyl ether monomers of the general formula.
H2C=C H--O--RLl
wherein R4 is an alkyl group of from 1 to 8 carbon atoms,
an aryl group of from 6 to 10 carbons~ or a monovalent
aliphatic radical of from 2 to 10 carbon atoms, which
aliphatic radical may be hydrocarbon or oxygen-containing,
e.g., an aliphatic radical with ether linkages, and may
also contain other substituents, such as halogen and
carbonyl. Rxamples of these monomeric vinyl ethers include
vinyl methyl ether, vinyl ethyl ether, vinyl n-butyl ether,
vinyl 2-chloroethyl ether, vinyl phenyl ether, vinyl iso-
3~ ~
--l~o--
butyl ether, vinyl cyclohexyl ether, p-butyl cyclohexyl
ether, vinyl ekher or p-chlorophenyl glycol.
Other comonomers are those comonomers which contain
a mono- or dinitr;le function. Examples of these include
methylene glutaronitrile, (2,LI-dicyanobutene-1), vinyl-
idene cyanide, crotonitrile, fumarodinitrile, maleodi- ~;
nitrile.
Other comonomers include the esters of olefinically
unsaturated carboxylic acids,preferably the lower alkyl ~ -~
esters of alpha,beta-olefinically unsaturated carboxylic
acids and more preferred the esters having the structure~
GH2 C---COOR2 ':' '~
R1
wherein R1 is hydrogen, an alkyl group having from 1 to Ll:
carbon atorns, or a halogen and R2 is an alkyl group having
from 1 to 2 carbon atoms. Compounds of this type include
methyl acrylate, ethyl acrylate, methyl methacrylate,
ethyl methacrylate and methyl alpha-chloro acrylate. Most
preferred are methyl acrylate, ethyl acrylate, methyl metha-
crylate and ethyl methacrylate.
Another class of nitrile resins are the graft co~
polymers which ha~e a polymeric backbone on which branches
of another polymeric chain are attached or grafted.
Generally the backbone is preformed in a separate reaction. ;
Polyacrylonitrile may be grafted with chains of styrene,
~ 7
-41-
vinyl acetate, or methyl methacrylate, for example. The
backbone may consist of one, two, three~ or more com-
ponents, and the grafted branches may be composed of one,
two, three or more comonomers.
The most promising products are the nitrile co-
polymers that are partially grafted on a preformed
rubbery substrate. This substrate contemplates the use
of a synthetic or natural rubber component such as poly-
butadiene, isoprene, neoprene, nitrile rubbers, natural
rubbers, acrylonitrile-butadiene copolymers, ethylene-
propylene copolymers, and chlorinated rubbers which are
used to strengthen or toughen the polymer. This rubbery
component may be incorporated into the nitrile containing
polymer by any of the methods ~hich are well known to
those skilled in the art, e.g.~ direct polymerization of
monomers, grafting the acrylonitrile monomer mixture onto
the rubber backbone or physical admixtures of the rubbery
component. Especially preferred are polymer blends derived
by mixing a graft copolymer of the acrylonitrile and co-
monomer on the rubber backbone with another copolymel of
acrylonitrile and the same comonomer. The acrylonitrile
based thermoplastics are frequently polymer blends of a
grafted polymer and an ungrafted homopolymer.
Commercial examples of nitrile resins include B~EX
210 resin, an acrylonitrile-based high nitrile resin con-
taining over 65% nitrile, and LOPAC ~ resin containing
37
L2_
over 70% nitrile, three-fourths of it derived from metha-
crylonitrile.
In order to better rnatch the viscosity ch~racteristics
of the thermoplastic engineering resin, the polycarbonate
and the block copolymer, it is sometimes useful to first
blend the dissimilar thermoplastic engineering resin with
a viscosity modifier before blending the resulting mixture
with the ~lyccr~on~e and block copolymer. Suitable viscosity
modifiers have a relatively high viscosity, a melt temper-
ature of over 230 C, and possess a viscosity that is notvery sensitive to changes in temperature. Examples Or suit-
able viscosity modifiers include poly(2,6-dimethyl-1,4-
phenylene~oxide and blends Or poly(2,6-dimethyl-1,4-phenyl-
ene)oxide with polystyrene.
~he poly(phenylene oxides) included as possible
viscosity modifiers may be presenked by the following
formula:
- ~
L
~o
I ,
_ R'l m
wherein ~1 is a monovalent substituent selected from the
group consisting Or hydrogen, hydrocarbon radicals free Or
a tertiary alpha-carbon atom, halohydrocarbon radicals
37
having at least two carbon atoms between the halogen
atom and phenol nucleus and being ~ree Or a tertiary
alpha-carbon atom, hydrocarbonoxy radicals free of
aliphatic, tertiary alpha-carbon atoms, and halohydro-
carbonoxy radicals having at least two carbon atomsbetween the halogen atom and phenol nucleus and being free
of an aliphatic, tertiary alpha-carbon atom; R'l is the
same as Rl and may additionally be a halogen; m is an
integer equal to at least 50, e.g., rrom 50 to ~00 and
preferably 150 to 300. Included among these preferred
polymers are polymers having a molecular weight in the
range of between 6,ooo and 100,000, preferably 40,000.
Preferably, the poly(phenylene oxide) is poly(2,6-di-
rnethyl-1,4-phenylene)oxi.de.
Commercially, the poly(phenylene oxide) is available
as a blend with styrene resin. These blends typically
comprise between 25 and 50% by weight polystyrene units,
and are available ~nder the ~
trade ~ NORYL ~ thermop~astic resin~ The prererred
molecular welght when employing a poly~phenylene oxide)/
polystyrene blend is between 10,000 and 50~000, preferably
around 30,000.
The amount Or viscosity modifier employed depends
primarily upon the di~erence between the viscosities o~
khe block copolymer and the engineering thermoplastic resin
at the temperature Tp. The amounts may range from O to 100
37
parts by weight viscosity modifier per 100 parts by weight ~ -
engineering thermoplastic resin3 preferably from 10 to 50
parts by weight per 100 parts of engineering thermoplastic
resin.
There are at least two methods (other than the absence
of delamination~ by which the presence of an interlocking
network can be shown. In one method3 an interlocking net~
work is shown when moulded or extruded objects made from
the blends of this invention are placed in a refluxing
solvent that quantitatively dissolves away the block co-
polymer and other soluble components3 and the remaining
polymer structure (comprising the thermoplastic engineer-
ing resin and ~lycarbonate)still has the shape and con-
tinuity of the moulded or extruded object and is intact
structurally without any crumbling or delamination, and
the refluxing solvent carries no insoluble particulate
matter. If these criteria are fulfil]ed, then both the
unextracted and extracted phasescre interlocking and
continuous. The unextracted phase must be continuous - `
because it is geometrically and mechanically intact.
The extracted phase must have been continuous before
extraction, since quantitative extraction of a dispersed
phase from an insoluble matrix is highly unlikely.
~inallyg interlocking networks must be present in order
to have simultaneous continuous phases. Also, confirmation
of the continuity of the unextracted phase may be
-ll5~
conrirmed by microscopic examination. In the present blends
containing more than two components, the interlocking
nature and continuity of each separate phase may be
established by selective extraction.
In the second method, a mechanical property such as
tensile modulus is measured and compared with that expected
from an assumed system where each continuous iso-
tropically distributed phase contributes a fraction of
the mechanical response, proportional to its compositional
fraction by volume. Correspondence of the two values
indicates presence of the interlocking network, whereas,
if the interlocking network is not present, the measured
value is different than that of the predicted value.
An important aspect of the present invention is that
the relative proportions of the various polymers in the
blend can be varied over a wide range. The relative
proportions of the polymers are presented below in parts
by weight (the total blend comprising 100 parts):
Parts by Preferred
weight parts by
_ight
Dissimilar engineering
thermoplastic resin 5 to 48 10 to 35
Block copolymer 4 to 40 8 to 20
~ -46- ~ 3~
The polycarbonate is present in an amount greater
than the amount of the dissimilar engineering thermo-
plastic, i.e., the weight ratio of polycarbonate to
dissimilar engineering therrnoplastic is greater than
1:1. Accordingly, the amount of polycarbonate may vary
from 30 parts by weight to 91 parts by weight, prefer- -
ably from 48 to 70 parts by weight. Note that the rninimum
amount of block copolymer necessary to achieve these
blends may vary with the particular engineering thermo-
plastic.
The dissimilar engineering thermoplastic resin,
polycarbonate and the block copolymer may be blended in any
manner that produces the interlocking network. For example,
the resin, polycarbonate and block copolymer may be
dissolved in a solvent common for all and coagulated by
admixing in a solvent in which none of the polymers are -
soluble. But, a particularly usef`ul procedure is to
intimately mix the polymers in the form of granules and~or
powder in a high shear mixer. "Intimately mixing" means
to mix the polymers with sufficient rnechanical shear and
~e~r~l ~o-rV to ensure that interlocking of the various
:
~ 2~ 7
_1~7_
networks is achieved. Intimate mixing is typically
achieved by employing high shear extrusion compounding
machines, such as twin screw compounding extruders and
thermoplastic extruders having at least a 20:l L/D ratio
and a compression ratio of 3 or 4:l.
The mixing or processing temperature (Tp) is selected
in accordance with the particular polymers to be blended.
For example, when melt blending the polymers instead of
solution blending, it will be necessary to select a
processing temperature above the melting point of the
highest melting point polymer. In addi.tion, as explained
more fully hereina~ter, the processing temperature may
also be chosen so as to permit the isoviscous mixing of
the polymers. The mixing or processin~ temperature may be
between 150C and Ll00C, preferably between 230C and
300C.
Another parameter that is important in melt blendin~
to ensure the formation of interlocking networks is matching
the viscosities of the block copolymer,~lY~rbnateand the
dissimllar engineering thermoplastic resin (isoviscous
mixing) at the temperature and shear stress of the mixing
process. The better the interdispersion of the engineering
resin and ~lycar~nate inthe block copolymer network, the
better the chance for formation of co-continuous inter-
locking networks on subsequent cooling. Therefore, it hasbeen found that when the block copolymer has a viscosity
3~7
-4&-
n poise at temperature Tp and shear rate of 100 s 1,
it is pref'erred that the engineering thermoplastic resin
and/or thepo~ca~onate have such a viscosity at the temper-
ature Tp and a shear rate of 100 s that the ratio of the
viscosity O:e the block copolymer divided by the viscosity
of the engineering thermoplastic and/orpolycarbonate be ~ ,
between 0.2 and ll.o, preferably between o.8 and 1.2.
Accordingly5 as used herein, isoviscous mixing means
that the viscosity of the block copolymer divided by the
viscosity of the other polymer or polymer blend at the
temperature Tp and a shear rate of 100 s 1 is between ~ `
0.2 and 4Ø It should also be noted that within an
extruder, there isawide distribution of shear rates.
Therefore, isoviscous mixing can occur even though the
viscosity curves of two polymers differ at some of the
shear rates.
In some cases, the order of mixing the polymers is
critical. Accordin~ly. ~ne may choose to mix the block
copolymer with the ~lyar~o~te or obher polymer first, and
2~ then mix the resulting blend with the dissimilar engineer-
ing thermoplastic, or one may simply mix all the polymers
at the same time. There are many variants on the order
of mixing that can be employed, resulting in the multi-
component blends of the present invention. It is also
clear that the order o~ mixing can be employed in order
to better match the relative viscosities of the various
polymers~
-4g-
The block copolymer or block copolymer blend may be
selected to essentially match the viscosity Or thç
engineering thermoplastic resin and~or polycarbonate.
Optionally, the block copolymer may be mixed with a
rubber compounding oil or supplemental resin as
described hereinafter to change the viscosity charac-
teristics Or the block copolymer. ~-
The particular physical properties of the block
copolymers are lmportant in forming co-continuous inter-
locking networks. Specifically, the most preferred blockcopolymers when unblended do not melt in the ordinary
sense with increasing temperature, since the vi~cosity
of these polymers is highly non-Newtonian and tends to
increase without limit as ~ero shear stress is approached.
Further, the viscosity Or these block copolymers is also
relatively insensitive to temperature. This rheological
behaviour and inherent thermal stability of the block co ;
polymer ehhances its ability to retain its network
(domain) structure in the melt 50 that when the various
blends are made~interlocking and continuous networks are
formed.
The viscosltY.behaviour o~ the en~ineering thermoplastic
resins, and ~carbonates on the other hand, is more sensitive
to temperature than that Or the block copolymers. Ac-
cordin~ly, it is often possible to select a processingtemperature Tp at which the viscosities o~ the block
237
-50-
copolymer and dissimilar engineering resin and/or poly-
ccr~on~e iall within the required range necessary to form
interlocking networks. Optionally, a viscosity Inodlfier,
as hereinabove described, may first be blended with the
engineering thermoplastic resin orp~ycar~nate to achieve the
necessary viscosity matching.
The ~end of partially hydrogenated block copolymer,
~lgcar~nate ald dissimilar engineering thermoplastic resin
may be compounded with an extending oil ordinarily used
in the processing of rubber and plastics. Especially
preferred are the types of oil that are compatible with
the elastomeric polymer blocks of the block copolymer.
While oils of higher aromatics content are satisfactory,
those petroleum-based white oils having low volatility and
less than 50% aromatics content as determined by the clay
gel method (tentative ASTM method D 2007) are particularly
preferred. The oils preferably have an initial boiling
point above 260C.
The amount of oil employed may vary ~rom O to 100 phr ~ -
(phr = parts by weight per hundred parts by weight of
block copolymer), preferably from 5 to 30 phr.
The blend of partially hydrogenated block copolymer~
~l~carb~Qt-eand dlssimilar engineering thermoplastic resin
may be further compounded with a resin. The additional
resin may be a flow promoting resin such as an alpha-
methylstyrene resin and an end-block plasticizing resin.
z~
-51-
Suitable end-block plasticizing resins include coumarone-
indene resins~ vinyl toluene-alpha-methylstyrene co-
po]ymers, polyindene resins and low molecular weight
polystyrene resins.
The amount of additional resin may vary from 0 to
100 phr, prefer bly from 5 to 25 phr.
Further the composition may contain other polymers, ;~
fillers, reinforcements, anti-oxidantsg stabilizers~ -
fire retardants, antl-blocking agents and other rubber
and plastic compounding ingredients.
Examples of fillers that can be employed are mentioned
in the 1971-1972 Modern Plastics Encyclopedia, pages 240-247.
Reinforcements are also useful in the present polymer
blends. A reinforcement may be definecL as the material that
is added to a resinous matrix to improve the strength of
the polymer. Mos~ of these reinforcing materials are in-
organic or organic products of high molecular weight.
Examples of reinforcements are glass fibres, asbestos, ~
boron fibres, carbon and graphite fibres, whiskers, quartz
and silica fibres, ceramic fibres, metal fibres, natural
organic fibres, and synthetic organic fibres. Especially
preferred are reinforced polymer blends containing 2 to
~0 per cent by weight of glass fibres, based on the total
weight of the resulting reinforced blend.
The polymer blends of the invention can be employed
as metal replacements and in those areas where high
performance is necessary.
-52~
In the illustrative Examples and the comparative
Example given below, various polymer blends were prepared
by mixing the polymers in a 3.125 cm Sterling Extruder
having a Kenics Nozzle. The extruder has a 24:1 L/D
ratlo and a 3.8:1 compression ratio screw.
The various materials employed in the blends are listed
below:
1) Block copolymer - a selectively hydrogenated block
copolymer according to the invention having a
structure S-EB~S.
2) Oil - TUFFLO 6056 rubber extending oil.
3~ Nylon 6 - PLASKON ~ 8207 polyamide.
4) Nylon 6-12 - ZYTEL ~ 158 polyamide.
5) Polypropylene - an essentially isotactic poly-
propylene having a melt flow index of 5
(230C/2.16 kg).
6) Poly(butylene terephthalate) (PBT) - VALOX
310 resin.
~ 7) Polycarbonate - MERLON ~ M-40 polycarbonate.
8) Poly(ether sulphone) - 200P.
9) Polyurethane - PELLETHANE ~ CPR.
10) Polyacetal - DELRIN ~ 500.
11) Poly(acrylonitrile-~tyrene) - BAREX ~ 210.
12) Fluoropolymer - TEFZEL ~ 200 poly(vinylidene
fluoride) copolymer.
323~
In all blends containing an oil component, the block
copolymer and oil were premixed prior to the addition of
the other polymers.
Illustrative Example I
. . .
Various polymer blends were prepared according to the
invention. A blend of two block copolymers of higher and
lower molecular weight was employed in some polymer blends
in order to better match the viscosity with the poly-
carbonate and/or other dissimilar engineering thermo-
plastic resin. In some blends, an oil was mixed with
the block copolymer in order to better match viscosities.
Comparative blends not containing a block copolymer were
also prepared. However, these blends were not easily
mixed. For example, blend 110 containing polycarbonate
and Nylon 6 suffered from melt fracture and extreme die
swell surging. In contrast, in each blend ~ontaining a
block copolymer, the polymer blend was easily mixed, and
the extrudate was homogeneous in appearance. Further, ln
each blend containing a block copolymer, the resulting
polyblend had the desired continuous, interlocking net-
works as established by the criteria hereinabove described.
The compositions and test results are presented below
in Tables 1 and 2. The compositions are listed in percent ?
by weight.
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-~2~
The results of the above blends indicate the un-
obvious properties for the present blends. For example,
by comparing blend 109 with blends 91 and 92, it can be
seen that at a ratio of polycarbonate to PBT of 3:1, by
increasing the amount of' the block component from 0 to
15 to 30%, the heat distortion temperature does not drop
as one would expect instead, the heat distortion temper-
ature is actually higher in blends containing the block
copolymer than in blend 109 not containing the block co-
polymer. Typically, when adding an amorphous rubber to
a thermoplastic~ one would expect a significant decline in
heat distortion temperature since the heat distortion
temperature of the rubber is very low.
It is also important to note that with increasing
amounts of block copolymer, the Izod impact strength in- -
creases significantly while the heat distortion temper-
ature is not significantly effected. This is dramatically ~ ;
shown by comparing the ratio of the percent increase in
impact strength divided by the percent change in heat
distortion temperature. For example, by examining the
ratio of the relative increase in Izod impact strength
(at 23C) over ~he relative decrease in heat distortion ~:
temperature for polymer blends as the percentage of
block copolymer is increased from 0% to 15% at a fixed
3:1 ratio polycarbonate to dissimilar engineering
thermoplastic, it can be seen that much larger than
-63- ~ 2 3 ~
expected values are obtained. One ski]led in the art
would typically expect this value to be positive and
less than 1. However, for blends containing nylon 6,
a fluorinated copolymer, a polyacetal, and poly(butylene
terephthala-te), the ratios are minus 142, minus 23, 28
and minus 37. The minus values are particularly out-
standing since these represent an increase in heat
distortion temperature with an increase in block co-
polymer.
Illustrative Example II
~arious additional blends were prepared in a
similar manner to those in illustrative Example I.
The various blends are presented in Table 3. In all
cases containing a block copolymer, the polyblends
possessed the desired interlocking network structure.
'
' ~, .'
: ' -
; ~
