Note: Descriptions are shown in the official language in which they were submitted.
The invent:ion relates to a cornposition containing a
partially hydrogenated block copolymer comprising at least
two terminal polymer blocks A Or a monoalkenyl arene having
an avera~e molecular weight of f'rom 5,000 to 125,000 and
at least one lnterrnediate polymer block B of a conjugated'
diene having an average molecular weight of from 10,000 to
3005000, in which the terminal polymer blocks A const1tute
~rom 8 to 55~ by weight Or the blocl: copolymer and no more
than 25% Or the arene double bonds Or the polymer blocks
and at least 80% of the aliphatic double bonds Or 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, f'or example, in
automotive applications.
For a particular application~ a single thermoplastic
resin may not offer the combination of prope~ties 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
:
3~1
successful in limited cases~ SllCh as in the :improveTnent
of impact resistance for thermoplastic resins, e.g.,
polystyrene, polypropylene and poly(vinyl chloride),
using special blending procedures or additives for this
purpose. However, in general, blending of thermoplastic
resins has not been a successrul route to enable one to
combine into a single material the desirable individual
characteristics Or two or more polymers. Instead, It h;ls
often been found that such blending results ln combinir-g
the worst features of each with the result being a
material Or 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 fr~m
the fact that thermodynamics teaches that most combinations
Or polymer pairs are not misc1ble, although a number of
notable exceptions are known. More importan-tly, most
polymers adhere poorly to one another. As a result, the
, :
interraces between component domains (a result of their
mmisclbility~ represent areas Or severe weakness in blends
~and, therefore, provide natural flaws and cracks wh1ch
reæult in facile mechanical failure. Bècause Or this,
most polymer pairs are said to be "incompatible". In some
instances the term compatlbility is used synonymously ~ `
with miscibility, however, cumpatlbility is used here in
a more general way that describes the ability to combine
two polymers togrther for beneficial results and may or
may not connote miscibility.
':' . :
23~
One method which may be used to circumvent this
problern in polymer blends is to "compatibilize" the two
polymers by blending in a third component, orten referred
to as a "compatibili~ing agent", that possesses a du~L
solubility nature for the two polymers to be blended.
Examples of this third component are obtained in b]ock
or graft copolymers. As a result Or this characteristic,
this agent locates at the interface between components
~ and greatly improves interphase adhesion and thererore
increases stability to gross phase separation.
The invention 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 solubility characteristics.
The materials used for this purpose are special block co
polymers capable Or thermally reversible self-cross-linkingO
Their action in the present invention is not that visualized
by the usual compatibilizing concept as evidenced by the
general ability of these materials to perrorm similarly
for a wide range Or blend components which do not conform
to the solubility requirements of the previous concept.
Now7 the inventlon provides a composition containing
a partially hydrogenated block copolymer comprising at
least two terrninal polymer blocks A Or a monoalkenyl arene
~5 having an average molecular weight Or from 5,000 to 125~000,
and at least one intermediate polymer block B Or a con-
3~
jugated diene having an average molecular weight of from 107000 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 a~ene double bonds of the
polymer blocks A and at least 80% of the aliphatic double bonds of the
polymer blocks B have been reduced by hydrogenation, which composition is
characterized in that the composition comprises:
(a) ~ to 40 parts by weight of the partially hydrogenated block
copolymer;
(b) a thermoplastlc polyurethane having a generally crystalline
structure and a melting point over 120C;
(c) 5 to 48 parts by weight of at least one dissimilar engineering
thermoplastic resin being selected from the group consisting of polyamides,
polyolefins, thermoplastic polyesters, poly(aryl ethers), poly(aryl sulphones),
polycarbonates, acetal resins, halogenated thermoplastics, and nitrile resins,
in which the weight ratio of the thermoplastic polyurethane to the dissimilar
engineering thermoplastic resin is greater than l:l so as to form a polyblend
wherein at least two of the polymers form at least partial continuous mter- .
locked networks with each other. :~
In another aspect, the invention provides a process for the
preparation of a composition as defined above, charac~erized in that
(a) 4 to 40 parts by weight of a partially hydrogenated block copolymer
comprising at leas~ 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 conjugated diene having an average mole~
cular weight of from 10,000 to 300,000, in which ~he 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 blocXs A and at least 80% of
the aliphatic double bonds o~ the polymer blocks B have been reduced by
hydrogenation, are mixed at a processing temperature Tp of between 150C and
400 C with ~ r
(b) a thermoplastic polyurethane having a generally crystalline
structure and a melting point of over 120C, and
-- 5 --
3~9
(c) 5 to ~8 parts by weight of at least one dissimilar engineering
thermoplastic resin being selected from the group consisting of polyamides,
polyolefins, thermoplastic polyesters, poly(aryl ethers), poly(aryl sulphones),
polycarbonates, acetal resins, halogenated thermoplastics and nitrile resins,
in which the weight ratio of the thermoplastic polyurethane to the dissimilar
engineering thermoplastic resin is greater than 1:1 so as to form a polyblend
wherein at least two of the polymers form at least partial continuous inter-
locked networks with each other.
The block copolymer of the invention effectively acts as a
mechanical or structural stabilizer which interlocks
- 5a -
--6--
the various polymer structure ne~works and prevents the
consequent separation O.r the polymers during processing
and their subsequent use. As defined more ~ully herein-
after, the resulting structure Or the polyblend (short
~5 for "polymer blend") is that Or at least two partial
continuous interlocking networks. q'his 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 con~inuous
networks whlch lnterlock with each other. Preferably, the
block copolymer and at least one other polymer have partial
~ ~ continuous interlocking networlc structures. In an ideal
;~ 15~ situation all of the polymers would have complete con-
::: .: :
~ tinuous networks which interlock with each other. A ~
,
partial continuous network means that a portion Or the
; polymer has a continuous network phase structure while
,
~ ~ the other portion has a disp'erse phase structure. Prefer-
! ~ 20 ` ~ ably, a major proportion (greater than 50% by weight) of
the partial continuous network is continuous. As can be
readily seen, a large variety o~ blend structures is
possible since the structure Or the polymer in the blend
may be completely continuous, completely disperse, or
partially continuous and partially disperse. Further yet,
the disperse phase of' one polymer may be dispersed in a
-7~
second polymer and not ;n 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 i.nvolved. The subscript
"c" signifies a continuous structure while the subscript
"d" signifies a disperse structure. Thus, the desi.gnation
''AcB'' means that polymer A is continuous with polymer B,
and the designation "BdC" means that polymer B is disperse
10 ~ ln polymer C, etc.
AcB AcC BcC
AdB AcC BcC
AcB AcC BdC
BdA Ac~ BcC
15~ BdC AcB AcC
CdA AcB AcC
C B 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 signif'icant deterioration in
another physical property. In the past this has not
always been possible. F'or 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 signif'ican-tly reduced heat
distortion temperature (HDT). This results f'rom 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.
However, in the present invention it is possible in
some cases to significantly improve impact strength
while not detracting from the heat distortion temper- ~
ature. In fact,when the relative increase in Izod impact -
strength is measured against the relative decrease in ~ '
HDT, the value o~ the ratio is of'ten much higher than
one would expect. For example, in blends containing a
thermoplastic polyurethane, block copolymer, and other
engineering thermoplastics such as polycarbonates, this
ratio is about 3, whereas one would typically expect
positive values of less than 1.
_ .
.
It is partlcularly fiurprising that even just small
amounts Or the block copolymer are sufricient to stabilize
the structure of the polymer blend over very wide relative
concentrations. For example, as little as four parts by
5 weight of the block copolymer is sufficlent to stabilize
a blend of 5 to 90 parts by weightpolyureth~ewith 90 to
5 parts by weight of a dissim.ilar engineering thermoplastic.
In addition, it is also surprising that the block co-
polymers are useful in stabilizlng polymers of such a wide
variety and chemical make-up. As exp.lained more fully
hereinafter9 the block copolymers have this ability to ~
stabilize a wide variety of polymer over a wide range of
concentrations since they are oxidat:ively 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 foY-mi.ng the various polyblends
is greatly improved by employing the block copolymers as
stabilizers.
~:~ 20 The block copolymers employed in the compo.sition
according to the invention may have a variety of geometrical
structure, since the invention doe~ not depend on any
specific geometrical 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 the polymers :is de-termined by
; their methods of polymerization. For example, linear
polymers result by sequential introduction Or the
desired monomers into the reaction vessel when using
such initiators as lithium-alkyls or dilithio-stilbene~
~ or by coupling a two-segment block copolymer with a ~i~
- di.functional coupling agent. Branched structures,on the
other hand, may be obtained by the use of suitable
coupling agents having a runct:ionality with respect to ~
the precursor polymers Or three or more. Coupling may be ~ -
effected with rnultifunctional coupling agents, such as
dlhaloalkanes or -alkenes and divinyl benzene as well as
certain polar compounds, such as sil.icon halides, siloxane,
or esters Or monohydric alcohols with carboxylic acids.
The presence 0r any coupling residues in the polymer may
be ignored for an adequate description of the polymers
forming a part of the compositions of this invent:ion.
.
~ Likewise, in the generic sense, the specific structures
: . , .
also may be ignored. The invention applies especially
20 ~ to the use of selectively hydrogenated polymers having
the configuration before hydrogenation of the following
typical species:
polystyrene~polybutadi.ene-polystyrene (SBS)
polystyrene-polyisoprene-po].ystyrene (SIS)
poly(alpha methylstyrene)polybutadiene-
poly(alpha-methylstyrene) and
-10-
poly(alpha-methylstyrene)poly;.soprene-
poly(alpha-methylstyrene~.
Both polymer blocks A and B may be either homopolymer
or random copolymer ~locks as long as each polymer block
predomlnates in at least one class of 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 conjugate~d diene
as long as the polymer blocks A indi.vidual:ly predornirlate
~10 in monoalkenyl arene units. The term "monoalkenyl arene"
; w.ill be taken to include especially styrene and its
~: : analogues and homologues including alpha-methylstyrene
and .ring-substituted styrenes, particularly ring-methyl-
ated styrenes. The preferred monoalkenyl arenes are
styrene and alpha-methylstyrene, and styrene is
particularly preferred. The polymer blocks B may comprise -~
; : homopolymers Or a conjugated diene~ such as butadiene or
isoprene~ and copolymers of a conjugated diene wîth a
~, ;, , :
monoalkenyl arene as long as~the polymer blocks B pre- :
~20 ~ dominate in conjugated diene units. When the monomer
employed is butadiene~ i.t 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 (~B). If the conjugated diene employed is
--ll--
isoprene, the resulting hydrogenated product ls or : :
resembles a regular copolymer block o~` 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 alkY.l compound with
nickel or cobalt carboxylates or alkoxides under such
conditions as t,o substantially completely hydrogenate ~ :
: at least 80% Or the aliphati.c double bonds, while
hydrogenating no more -than 25% of the alkenyl arene
aromatic double bonds. Prererred block copolymers are
those where at least 99% of the allphatic double bonds
are hydrogenated while less than 5% of the aromatic
double;bonds are hydrogenated.
15~ ~ The average molecular weights of the individual ~.
blocks may vary within certaln limits. The block co
poly~er present in the composition according to the :~
invention has at least two terminal polymer blocks A of
~. ~ . ,:
a monoalkenyl arene having a~:number average molecular
~:20: :~ weight of from 5,000 to 125,000, preferably from 7,00:0
~ to 60,000, and at least one intermediate polymer block B
~ . of~a conjugated diene having a number average molecular~
weight of from 10000 to 300,000, preferably from 30,000
to 150~000. These molecular weights are mo,st accurately
determined by tritium counting methods or osmotic pressure
measurements.
-12 ~ 2~
The proportion o.f the polymer blocks A of the mono-
alkenyl arene should be between 8 and 55~0 by weight of
the block copolymer, preferably between 10 and 30% by
weight.
Polyurethanes, otherwise known as isocyanate resins,
are employed in the composition according to the invention
as long as they are thermoplastic as opposed to thermo
setting. For example, polyurethanesformed from toluene
di-isocyanate (TDI) or diphenyl methane 4,4-di-isocyanate
(MDI) and a wide range of po]yols, such as, polyoxyethylene
glycol, polyoxypropylene glycol, hydroxy-terminated poly- ~.
esters, polyoxyethylene-oxypropylene glycols are sultable.
These thermoplastic polyurethanes are available under
D~ ~ ~~
the trade r~ame Q-THANE'Y and under the trade ~a~e PELLETHANE ~
CPR. ~ - .
:
: The term "dissimilar engineeri.ng thermoplastic resin" ~.
refers to engineering thermoplastic resins different from ~;
those encompassed by the polyurethanes present in the com~
~ ..
positions according to the invention.
~::20 ~ The term ~engineering thermoplastic resin" encompasses
the various polymers found in the classes listed in Table A
below and thereafter define.d in the specification.
TABLE A
1. Polyolefins
: 25 2. Thermoplastic polyesters
. Poly(aryl ethers) and poly(aryl sulphones)
`:~
-13~ 2 ~
~ .,
4. Polycarbonates
5~ Acetal resins
6. Polyarnides
7. Halogenated thermoplastics ~ -
8. Nitrile resins
Preferably these engineering thermoplastic resins
have glass transition temperatures or apparent crystalline
melting points (defined as that temperature at which the
modulus, at low stress, shows a catastrophic drop) of
over 120C, preferably between 150C and 350C, and are
capable of forming a continuous network structure
through a thermally reversible cross-linking mechanism.
Such thermally reversible cross-linking mechanisms in~
~ ; clude crystallites, polar aggregations, ionic aggregations,
`~ 15;~ lamellae, or hydrogen bonding. In a specific embodiment~
where the viscosity of the block copolymer or blended;
block copolymer composition at processing temperature Tp
and a~sh~r rate of 100 s 1 i.s n, the ratio of the~
ity of the engineering thermoplastic resins, or
20 ~ blend of engineering thermoplastic resin with viscosity
modifiers to n may be~between 0.2 and 4.0, preferably~O.8
and 1.2. As~used in the specification and claims, the
visoosity 0f the block copolymer, polyurethane and the
thermoplastic engineering resin is the "melt viscosity"
obtained by employing a piston-driven caplllary melt ~
rheometer at constant shear rate and at some consistent
: :: : :
,:
- 1 L~ %3~
temperature above melting, say 260 C. 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.
These various classes of engineering thermoplastics
are defined below.
The polyolefins, if present in the compositions ac-
cording to the invention are crystalline or crystallizabIe.
They may be homopolymers or copolymers and may be derived
from an alpha-olefin or 1-olefin having 2 to 5 carbon
15~ atoms. Examples of particular useful polyolefins include
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 polymer blend according
to the invention. The number average molecular weight o~
the polyolefins may be above 10,000, preferably above
5' In addition, the apparent crystalline melting
point may be above 100C, preferably between 100C and
~ 3
~ .
'
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,
; 5 pages 217-335 (1967).
When a high-density polyethylene is employed, it has
an approximate crystallinity of over 75% and a density in
,
,:
\
:,, ~ ~ \ : ~ :
: , ~ : : ,
~ ~,
~ .
~ 2
~16-
kilograms per litre (kg/l) o~ 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 Or
between 0.90 kg/l and 0.94 kg/l. The composition ac-
5 cording to the invention may contaln a polyethylene hav;~ng
a number average molecular weight o~ 50,000 to 5009000.
When a polypropylene is employed~ it is the so-
called isotactic polypropylene as opposed to atactic
polypropylene. The number average molecular weight Or the
~10 polypropylene er(lployed ~y ~ ~n excess o~ 100,000. r~ e r~oly~
propylene may be prepared using methods Or the prior
; art. Depending on the speciflc catalyst and polymer~
izat~ion 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 crystallize more completely. `
The preferred commercial polypropylenes are generally
;~; prepared us~ing a solid~ crystalline, hydrocarbon-in~
Z0~ soluble catalyst made from a titanium trichloride com- ~ ~n
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
Or ethylene or another alpha~olefin as comonomer.
-17-
The poly(1-butene) preferably has an lsotactic structure.
The catalysts used in preparing the poly(1-butene) are
preferably organo-metallic compounds commonly rererred to
as Ziegler-Natta catalysts. A typical catalyst is the
interacted product resulting from mixing equimolar quan-
tities of titanium tetrachloride and triethylaluminium.
The manufacturing process is normally carried out in an
inert diluent such as hexane. Manufacturing operations,
in all phases of polymer formation, are conducted in such
a manner as to ~uarantee rigorous exclusion of water even
in trace amounts.
.i . . .
One very suitable po1yolefin is poly(4-methyl-1-penterle).
Poly(4-methyl-1-pentene? has an apparent crystalline melt-
ing point of between 240 and 250C and a relative density
of between 0.80 and 0.85. Monomeric 4-methyl-1-pentene is
commerc;ally manufactured by the alkali~metal catalyzed
dimerization o~ propylene. The homopolymerization o~
4-methyl-1-pentene with Ziegler-Natta catalysts is ~escribed
in the Kirk-Othmer Enclopedi~a of Chemical Technology,
Supplement volume, pages 789-792 (second edition, 1971~.
However, the isotactic homopolymer Or 4-methyl-1-perltene
has certain technical defects, such as brittleness and
inadequate transparency. Therefore, commercially available
poly(4-methy].-1-perlterle) is actually a copolymer with
minor proportions of other alpha-olefins, together with
the addition of suitable oxidation and melt stabilizer
-18- ~ 2 3
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 namo TPX ~ resin. Typical
alpha-olefins are l;near 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
15 ~ ~ are thermoplastic as opposed to thermosetting. `~
~: ~ :
\` ~: .
'
~ : .
Q ~ 3~
-19-
One partlcularly user`ul. group Or po:Lyesters are tho (~
therrnoplastic polyesters prepared by condensing a di-
carboxylic acid or the :I.ower a:lkyl ester, acid hali.de,
or anhydride derivati.ves thereof with a glycol, accordi.ng
to methods well known in the art.
Among the aromatic and aliphatic dicarboxylic ac.lds
suitable .for preparing polyesters are oxal.ic acid, malonic
acid, succinic acid~ glutaric a.cid, adipi.c acidj suberic
acid, azelaic acid, sebacic ac:id, terephthalic acid, iso-
phthalic acid, p-carboxyphenoacetic aci.d, p,p'~icarboxydi.phenyl,
p,p'-dicarboxydiphenyl~ulE~lone, p-cal~boxyph~-~noxyac(:,~tic Cl(~ i.ti~
p-carboxyphenoxypropionic acid, p-carboxyphenoxybutyri.c acid~
p-carboxyphenoxyvaleric acid, p-carboxyphenoxyhexanoic acid,
p,p'-dicarboxydiphenylmethane, p,p-di.carboxydiphenylpropane,
p~p'-dicarboxydiphenyloctane, 3-alkyl.-4-(~-carboxyethoxy)-
:~ benzoic acid~ 2,6-naphthalene dicarboxylic acid, and 2,7-
naphthalene dicarboxylic acid. Mixtures of dlcarboxylic
acids can also be employed. Terephthalic acid is particularly
preferred. ~ .
The glycol~ suitable ror preparing the polyesters
include straight-chain alkylene gIycols of 2 to 12 carbon
atoms~ such as ethylene glycol, 1~3-propylene glycol,
1,6-hexylene glycol~ 1,10-decamethylene glycol, and 1,12-
dodecarnethylene glycol.. Aromatic glycols can be substitu~ed
in whole or in part. Suitable aromatic dihydroxy compounds
include p-xylylene glycol1 pyrocatechol, resorcinol,
3~)
-20-
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 prererred group of polyesters are poly(ethylene
terephthalate), poly(propylene terephthalate), and poly-
(butylene terephthalate). A much preferred polyester is
poly(butylene terephthalate). Poly(buty]ene terephthalate),
~ a crystalline copo]ymer, may be fornled by the polycondensati()n
of 1,4~butanediol and dimethyl terephthalatc or terepht;ha]:ic ~-~
acid, and has the generalized Iormula:
o~l~o~
n
where n varies from 70 to 140. The average molecular wei~ht
of the poly(butylene terephthalate) preferably varies ~rom
20~000 to 25,000.
Commercially avallable poly(butylene terephthalate) ls
available under the trade ~=e VALOX ~ thermoplastic
polyester. Other commercial polymers include CELANEX ~,
TENITE ~ and VITIJFF ~ .
Other useful polyes~ers include the cellulosic esters.
The thermoplastic cellulosic esters employed herein are
widely used as mouldirlg, coating and film-rorming materia:Ls
~
~38;~
and are well known. These materials include the solid
thermoplastic rorms Or cellulose nitrate, cellulose
acetate (e.g., cellulose diacetate, celluLose tri-
acetate), cellulose butyrate, cellulose acetate butyrate, ~ -
cellulose propionate, cellu]ose tridecanoate, carboxy-
methyl cellulose, ethyl cellulose, hydroxyethyl cellulose
and acetylated hydroxyethyl cellulose as described on
pages 25-28 of Modern Plastics Encyclopedia, 1971-72, and
references liste~ therein.
10Another useful polyester is a polypivalolactone. Poly-
pivalolactone is a linear polymer having recurring ester
structural units mainly of the formula:
; CH2 C(CH3)2 ~ C(O)O
~ ~ i.e., units derived rrom pivalolactone. Preferably, the poly-
,
~15 ester is a pivalolactone homopolymer. Also included, however,
are the copolymers of pivalolactone with no more tharl 50 Illol.%,
preferably not ~ore than 10 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 "heta-propiolactones" rerers to beta-
propiolactone (2-oxetanone) and to derivatives thereof which
carry no substituents at the beta-carbon atom of the lactone
ring. Prererred 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.
39
-2~
Examples Or useful monomers are:
alpha-ethy1-alpha-methyl-beta-propiolactone,
alpha-methyl-alpha-isopropyl-beta-propiolactone,
alpha-ethyl-alpha-n-butyl-beta-propiolactorle, : :
al.pha-chloromethyl-alpha-methyl-beta-propiolactone,
alpha,alpha-bis(chloromethyl)-beta-propiolactone, and
alpha,alpha-dimethyl-beta-propiolactone (pivalolactone). :~
These polypivalolactones have an average molecular welght in
excess of 20,000 and a melting point ln excess of 120C.
;lO Another userul polyester is a polycaprolactone.
~ Preferred poly(~-caprolactones) are substantially linear
~ polymers in which the repeating unit is:
~_ O
t - -C~i2- -C~l2 CH2 C.~l2 C}2
~ , ~ - _
~ These polymers have similar properties to the polyplvalo-
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 of re-
curring units having the formula:
-(O - G -0 - G'~
wherein Gisthe residuum of a dihydric phenol selected from :~
the group consisting of:
3~
-23-
.,' .
and
'
wherein R represents a bond between aromatic carbon atoms,
:~ - O - , - S - ~ - S -S-,or a divalent hydrc~carbon radical
having ~rom 1 to i8 carbon atoms inc~lusive, and G' is the
5~ residuum of a dibromo or di-iodobenzenoid compound
selected ~rom the group consisting O r:
IV
and
93 V ~ ~ ~
wherein R' represents a bond between aromatic carbon atoms,
O - , - S- -g - S - S - ,or a divalent hydrocarbon
~lO radical having from 1 to 18 carbon atoms inclusive, with
the provisions that when R i5 - 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, a is III.
`~
23~
-2~-
Polyarylene polyethers of' this type exhibit excellent physic.ll
properties as well as excellent therrnal ox:idative and
chemical stabillty. Cornmercial poly(ary:l polyethers) are
L~ available under the trade *~me ARYLON T ~ Polyary] ethers,
having a melt temperature Or between 280C and ~10C.
Another group Or userul engineering thermoplastic
resins include aromatic poly(sulphones) comprising re-
peating units of the rormula:
n which Ar is a bivalent aromatic radical and may vary
from unit to unit in the polymer chai.n (so as to rorm co-
polymers Or various kinds). Thermoplastic poly(sulphones)
generally have at least some units Or the structure:
~z~9 ~ :
~: 2
in which Z i5 oxygen or sulphur or the residue of an
aromatic diol, such as a 4,4'-bisphenol. One example Or
such a poly(sulphone) has repeating units Or the formula:
~,3 o <~s02~
~9~323~
: -25-
.
another has repeatlng units Or the formula:
~ ~ S ~ 2 - -
and others have repeating units of the formula: -
~ ~3 C3cl,3~
or copolymerized units in vario~s proportions of the~
formula:
: .
~ S2
: : 5 ~ and
~ ~ 52--
The thermoplastic poly(sulphpnes) may also have repeating :
units having the formula: ~
~3 ~3
.
Poly(ether sulphones) having repeating units Or the
following structure:
'
3239 ~
-26-
o~ So2~-
and poly(ether sulpholles) having repeatirl~ units Or the
following ~tructure:
_
`2~ C-3 ~ ~_ _
- _ Cli3
. n
: are also use~ul as engineering thermoplastic resins.
- The polycarbonates which may be preserlt in the com-
~5 positions acGording to the invention are of the general
formulae~
~: O ;
Ar-- A--Ar-- O-- C-- 0~
~: ; n ~ :
and - ::
. ~ .
Ar- O- C - 03
n
wherein Ar represents a phenylene or an alkyl, alkoxy,
halogen or nitro-substituted phenylene group; A represents~
a carbon-to-carbon bond or an alkylidene~ cycloalkylldene,
alkylene, cycloalkylene, azo~ :imino, sulphur, oxy~en,
sulphoxide or sulphone ~roup, and n is at least two.
%3~
The preparation of the polycarbonate~; is well known.
A preferred method Or preparatiorl is ba~ed on the reaction
carried out by dir3solving the dihydroxy cornponent in a
base, such as pyridine and bubbling phosgene into the
stirred solution at the desired rate. Tertlary amines may
be used to catalyze 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 tcmperature. The reactions
generally utilize equlmolar amounts o~ pho~gerle and di~
hydroxy reactants, however, the molar ra~io~; can be varied
dependent upon the reaction condltions.
In the farmulae I and II mentioned, Ar and A are,
preferably, p-phenylene and isopropylidene, respectively.
~15 This polycarbonate ls prepared by reacting para~para'-lsb~
propylidenediphenol with phosgene and is sold under the
trade mark LEXAN ~ and under the trade mark M~RLON Q
This commercial polycarbonate has a molecular weight Or
~ around 18,0QO, and a melt temperature of over 230C.
j~ 20 ~ ~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 ~`or best high temperature
properties aromatic rings are essential. The dihydroxy
compounds may include within the structure diurethane
linkages. Also, part Or the structure may be replaced by
siloxane linkage.
3~3
-2~
-
The acetal resins wh;ch may be present in the com-
positions according to th~ invention include the high
molecular weight polyaceta] homopolymers made by polymer-
izing formaldehyde or trioxane. These po~yacetal homo-
~ o,~5 polymers are conlmercia1ly availab:Le under the trade r~e
DELRIN ~. A related polyether-type resin is available
under the trade ~a~ PENTON V and has the structure:
CH2Cl
i ~ _ _o - CH2----C--C112 _
, ~ ' C~12Cl
` n
,
The acetal resin prepared from formaldehyde has a high
molecular weight and a structure typlfied by the fol:lowin~:
, .
H O ~ 2----C~12--O) H--
,: x
lO ~ where terminal groups are derived from controlled amounts Or
water and the x denotes a large (preferably 1500) number of
~ormaldehyde units linked in head to-tail fashion. To in-
crease khermal and chemical resistance~ terminal groups
- are typically converted to esters or ethers.
Also included in the term polyacetal resins are the
polyacetal copolyrners. These copolymers include block co-
polymers of formaldehyde with rnonomers or prepolymers of
other rnaterials capable of providing active hydrogens,
~8;23~
-29-
such as al~ylene glycol. , polyth:i.c)]s, v;nyl acetate-
acrylic acid copolymers 3 or reduced ~utadi.ene/acry~.c)nitri1e
polyTners .
Celanese has commcrcially available a copo].ymer o~
~ormaldehyde and cthylenc oxidc und~r the tradc name CL.L,~ON~
that is userul i.n thc ~lcnds o~ th( prcsent i.r~vent.i.c)n. 'I'llæse
copolymérs typically have a structure comprising recurrin~r
; units having the formula:
wherein each R1 and T~2 ls selected rrom thc ~;roup consist;.nlr
IO Of hydrogen~ lower alkyl and lower halogen substituted
.; ` alkyl radicals and whereirl n is an inte~c-~r 1`rorn zero to three
and whereln n is zero in ~rom 85% to 99.9% Or the rccurr-;ng
-
units.
Formaldehyde and trioxane can be copolymerized with
15i other aldehydes, cyclic ethers, vinyl compounds, ketcneæ,
cyclic carbonates, epoxides, isocyanates and ethers. These
compounds include ethylene oxideg 1,3-dioxolane, 1,3-dioxane,
1,3~dioxepene, epichlorohydrin, propylene oxide, isobutylene
oxide, and styrene oxide.
- ~30~ ~ 3~
By polyamide is meant a condensation prod~ct which
contains recurring aromatic and/or aliphatic amide groups
as integral parts of the main polymer chain3 such products
being known generically as "nylons". A polyamide may be
ob-tained 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-
izing a mono-aminocarboxylic acid or an internal lactam
thereof as defined above together wlth substantially equi-
molar proportions of a diamine and a dicarboxylic acid.
~ he dicarboxylic acid may be used in the form of a
; 15~ functional derivative thereof, for example an ester.
The term "substantially equimolecular proportions"~
; (of the diamine and of the dicarboxylic acid) is used to
cover both strict equimolecular proportions and the slight
depart ~ therefrom which are involved in conventional
.
' ~ ,
: ., ~
' ~ . .
techniques for stabilizing the viscoslty Or the resultant
polyamides.
As examples Or the said mono-aminomonocarboxylic acids
or lactams thereor there may be mentioned those compounds
5 containing from 2 to 16 carbon atoms between the amino and
carboxylic acid groups, said carbon atoms forming a ring
with the - CO.NH group in the case Or a lactam. As
particular examples Or aminocarboxylic acids and lactarns
there may be mentloned ~-aminocaproic acid, butyrolactam,
lO~ pivalolactam, caprolactam~ capryl-lactam, enan-tholactam,
undecanolactam, dodecanolactam and 3 and 4-amino benzoic
acids.
Examples Or the said diamines are diamines o~ the
general rormula }I2N(CH2)nNH2~ wherein n is an integer Or
15~ from 2 to 16, such as trimethylenediamine, tetramethylene-
diamine, pentamethylenediamine, octamethylenediamine~
decamethylerIediamine~ dodecarnethylenediamine, hexadeca-
~ ~ ,
methylenediamine, and especially hexamethylenediamine.
C-alkylated diamines, e.g., 2,2-dimethylpentamethylene- ~ ~`
- diamine and 2~2,4-and 2,4,4-trimethylhexamethylenediamine
are further examples. Other diamines which may be mentioned
.
a8 examples are aromatic diaminesg e-g., p-phenylene-
diamine, 4,4'-diaminodiphenyl sulphone, 4,4'-diaminodi-
phenyl ether and 4,lI'-diaminodiphenyl sulphone, 4,4'-di-
aminodiphenyl ether and 4~4'-diaminodiphenylmethane; and
cycloaliphatic diamines, for example diaminodicyclohexyl-
methane.
39
-32-
The said dicarboxylic a.cids may be aromatic~ for
; example isophthalic and terephthalic acids. Pre~erred
dicarboxylic acids are of the formula HOOC.Y.COOH,
wherein Y represents a divalent aliphatic radical
containing at least 2 carbon atoms, and examples of
such acids are sebacic acid, octadecanedioic acid,
suberic acid, azelaic acid, undecanedioic acid, glutaric-
acid, pimelic acid, and especia]ly adipic a.cid. Oxalic
acid is also a preferred acid.
Speci.rically the followin~ polyamides may be :in-
corporated in the thermop~.astlc polymer blends Or the
.
nventlon:
polyhexamethylene adipamide (nylon 6:6)
polypyrrolidone (nylon Ij)
polycaprolactam (nylon 6)
polyheptolactam (nylon 7)
polycapryllactam (nylon 8)
polynonanolactam (nylon 9)
. ~.. . .
polyundecanolactam (ny:lon 11)~
polydodecanolactam (nylon 12)
polyhexamethylene azelaiamide (nylon 6:9)
polyhexamethylene sebacamide (nylon 6~10)
polyhexamethylene isophtIIalamide (nylon 6:iP)
polymetaxylylene~ipamide (nylon MXD:6)
: 25 polyamide of hexamethylene diamine and n-dodecanedioic
acid (nylon 6:12)
polyamide of' dodecamethylenediam;ne and
n-dodecanediolc acid (nylon 12:12).
Nylon copolymers may also be used, ror example co- :
polymers Or the following: : .
hexamethylene ad;~amide/caprolactam (nylon 6:6/6)
hexamethylene adipami.de/hexamethylene-;.sophthala.mi.de
(nylon 6:6/6ip)
hexamethylene adipamide/hexamethylene-terephthalam:i.de
(nylon 6:6/6T)
trimethy],hexamethylene oxamide/hexamethylene oxam.ide
(nylon trirnethyl-6: 2/G: 2)
~ : hexamethylene adipamide/hexamethylene-azelaiamide
.~ ~ . (nylon 6:6/6:9)
hexamethylene adipamide/hexamethylene-azela.iamide/ ':
~:15 ~ caprolactam (nylon 6:6/6:9/6).
Also useful is nylon 6:3. This polyamide is the product
Or the dimethyl ester Or terephthalic acid and a rnixture O:r
: :
isomeric trimethyl hexamethylenediamine.
~: Pre~erred nylons include nylon 6,6/6, 11~ 12, 6/3
~20 and 6/12.
The number average molecular weights o~ the polyamides ~:
: may be above 10,000.
3~
Another group of useful engi.neering therrnoplastics in-
clude those halogenated thermoplastics having an essentially
crystal].ine structure and a melt point in excess of 120C.
These halogenated thermoplastics include homopolymers and
copolymers derived from tetrafl.uoroethylene, chl.orotrifluoro-
ethylene, bromotrifluoroethylene, vinylidene fluoride, and
vinylidene chloride.
Polytetrafluoroethylene (PTFE) is the name given to
fully rluorinated polymers of the basic chemical formula
~ C~12 - - CF2 ~ - which contain 76% by weight fluorine.
Th-se polymers are highly crystal.line and have a crystalline
3~
melting point of over 300 C. Comrnercial. Prl'FE; is avai.lable
~, ~f~ r~ ~Or~
~: under the trade ~a~ TLI?LON ~ and under the trade ~e
FL~ON ~ . Polychlorotri.fluoroethy:Lene (~CrJ'I~'E) and poly-
bromotrifluoroethylene (PBT~E) are also ava.ilable in high
molecular wei.~hts and can be ernployecl in the r,res(r-l~ in-
vention.
Especially preferred halogenated polymers are horno-
polyrners and copolym(?rs Or vinylidene rlllor:ide. Poly-
(vinyli.dene fluor:i.dc) homopolymers are the partially
fluori.nated pol.ymers Or the chem:i.(.al rorrnula -~--Cl-12 C1~2
: These polymers are tough linear polymers w;th a cry-;talline
melting point at 170 C. Comrnercial homopolymer i.s avail.able
under the trade ~u~ KYNAr~ ~ The term "poly(v;nylideno `
rluoride)" as used herein ref`ers not only to ~he normally
solid homopolymers Or vinylidene fluoride, but also to the
~: normally solid copolymers Or vinylidene f]uoride contalnin~
at least 50 mol.% o~ polymerized vinylidene fluoride units, ~
preferably at least 70 mol.% vinylidene fluoride and more ~ :
preferably at least 90 molO%. Suitable comonomers are
halogenated olefins containing up to ll carbon atoms, f'or
example, sym. dichlorodi~luoroethylene, vinyl ~luoride,
vinyl chloride, vinylidene chloride, perf.l.uoropropene~per-
f'luorobutadiene, chlorotrirluoroethylene, trichloroethylene
and tetrafluoroethylene.
Another useful group of halogenated thermoplastics
lnclude homopolymers and copolymers derived from vinylidene
chloride. Crystalline vinylidene chloride copolymers are
~ 2
-~6-
; especially preferred. ~'he normally crysta:l.l.;ne vinyliderle
chloride copolymers that are useful in the present in-
vention are those containing at least 70% by we.ight O.r
vinylidene chloride together wi.th 30% or less of a co-
polymerizable monoethylenic monomer. Exemplary of` such
monomers are vinyl chlor;de, vinyl acetate, vinyl
propionate, acrylonitrile, alkyl and aralky] acrylates
hav`ing alkyl and aralky]. groups of up to about 8 carbor
atoms, acrylic aci.d, acrylamide, vinyl alky] ethera,
vinyl alkyl ketones, acrolci.n~ al]yl ethers and others,
butadie~ne and chloropropene. i5nown ~I!rrlclry (.~orrl~)o it:ior~ . :
also.may be employed adva.ntageously. Representativ(? of`
such polymers are those composed of at least 70% by weight
of vinylidene chloride w:ith the remain(ler made UE) Or~ for
~ 15 exarnple, acrolein and vinyl chloride, acrylic acid and
acrylonitrile, alkyl acrylates and alkyl methacrylates,
acrylonitrile and:butadiene, acrylonitrile and ita.conic
acid, acrylonitrile and vinyl acetate, vinyl propionate
or vinyl chloride, allyl esters or ethers and vinyl
: 20 chloride, butadiene and vinyl acetate, vinyl propionate,
or vinyl chloride and vinyl ethers and vinyl chloride~
Quaternary polymers of similar monomeric composition will
also be known. Partlcularly useful for the purposes ~
the present invention are copolymers Or frorn 70 to 95% by
weight vinylidene chloride with the balance being vinyl
chlori.de. Such copolymers may contain conventional. amounts
and types of plasticizers, stabilizers, nuc:Leators and
extrusion aids. Further~ blends o~ two or more of such
normally crystalline vinylidene chloride polymers may
be used as well as blends cornprising such normally
crystalline 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 userul as engineering thermoplastic
resin are those thermoplastic materlals having an alpha,beta-
olefinically unsaturated mononitrile content Or 50% by
weight or greater. These nitrile resins rnay be homopolymers,
copolymers, grarts Or copolymers onto a rubbery substrate,
or blends of homopolymers and/or copo:Lymers.
The alpha,beta-olefinically unsaturated mononitriles
encompassed herein have the structure
CH2 ~ 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-
20 ~ nitrile, methacrylonitrile and ethacrylonitrile 4 The mostpreferred olefinically unsaturated nitriles are acrylo-
nitrile and methacrylonîtrile and mixtures thereof.
These nitrile resins may be divided into several
classes on t,he basi Or complexity. The simplest molecular
-38-
structure is a random copolymer, predomlnantly acrylonitrile
or methacrylonitrile. The most common example is a
styrene-acrylonitrile copolymer. Block copolymers of
acrylonitrile, in which long segments o~ polyacrylonitrile
alternate with segments Or polystyrene, or of` polymethyl
methacrylate, are also known.
Simultaneous polymerization of more than two co-
monomers produces an interpolymer, or in the case Or
three components, a terpolymer~ A large number of co~
monomers are known. ~hese include alpha-olefins o~from
2 to 8 carbon atoms, e.g.~ ethylene, propylene~ iso-
butylene, butene-1, pentene 1, and their halogen and
aliphatic substituted derlvatives as represented by vinyl
chloride and vinylidene chloride; monovinylidene aromatic
15~ hydrocarbon monomers o~ the general formula:
- - H2C ~ C \
wherein~R1 is hydrogen, chlorine or methyl and R2 i9 an
aromatic radical of 6 to 10 carbon atoms which may also
contain substituents, such as halogen and alkyl groups
attached to the aromatic nucleus~ e.g., styrene9 alpha-
methyl styrene, vinyl toluene, alpha chlorostyrene, ortho-
chlorostyrene~ para-chlorostyrene 3 meta-chlorostyrene,
ortho-methyl styrene, para methyl styrene, ethyl styrene,
3~
-39-
isopropyl styrene, d:ichlorostyrene and vinyl naphthalene.
Especially preferr~cl comonomers are isobutylene and styrene.
Another group Or comonomers are vinyl ~ster monomers
Or the general formula:
111
3C C,
C=O
wherein R3 i5 selected from the group comprising hydrogen,
alkyl groups of from 1 to 10 carbon atoms, aryl grOllp5 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 vinyl benzoate.
Similar to the foregoing and also use~ul are the
vinyl ether monomers of the general formula:
2C-C~I- - R4
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
al~o contain other substituents, such as halogen and
carbonyl. Examples o~ these mono~eric vinyl ethers include
vinyl methyl ether, vinyl ethyl ether, vinyl n~butyl ether,
vinyl 2-chloroethyl ether~ vinyl phenyl ether, vinyl iso-
~ 0--
butyl ether, viny.l cycloh~xyl ether, p-buty:L cycloil~xyl
ether, vinyl ether or p-chlorophelly~ ~lycol.
Other comonomers are those cornonomers which contcL;.n
a mono- or dinitrile :runction. Examples Or these include
methylene glutaronitri.]e, (2,4-dicyarlobuterle-1), virlyl-
idene cyanide, crotonitri:l.e, rumarotlinitri..le, rnclleo~i-
nitrile.
Other comonomers include the esters of` oler:inically
unsaturated carboxylic acids,l~rererably the lower a:l.ky].
esters Or alpha,beta-olef`:inically unsaturated carboxylic
acids and more preferred the este~rs hav:ing the structure: :
, ~ ~ C~2--C CO(:)R2
~1
wherein R1 is hydrogen, an alkyl group having from 1 to 4
carbon atoms, or a halogen and R2 is an al.kyl group havinp;
. : from 1 to 2 ca.rbon atoms. Compounds of this type include
~15 methyl aorylate, ethyl acrylate, methyl methacrylate~
ethyl methacrylate and methyl alpha-chloro acrylate. Most
preferred are methyl acryla-te, ethyl acrylate, methyl metha-
. crylate and ethyl methacrylate.
Another class of nitrile resins are the grart co- .
polymers wh.ich have a polymeric backbone on which branches :
o~ another pol.ymeric chain are attached or grafted.
Generally the backbone is preformed in a separate reaction.
Polyacrylonitrile may be grarted with chains Or styrene~ -
vinyl acetate, or met;l~yl methacry~ate, ror example. The
backbone may consist Or one, two, thrc?e, or more com-
ponents, and the grarted branc~es rnay be composed Or one,
two~ three or more comonomers.
The most pronlising product; are the nitrile co-
polymers that are partia:Lly grafted on a prerormed
rubbery substrate. This substrate contemplates the use
Or a synthetic or natural rubber cornponent such as poly-
butadiene, isoprene, neoprene, nitrile rubbers, natural
rubbers, acrylonitr1le-butadiene copo]yrners, ethylene-
~; propylene copolymers, and c})lorinated rubbers which are
used to strengthen or toughen the polymer. Th;s rubbery
cornponent may be incorporated into the nitrile containing
polymer by any Or the methods which are well known to
those skilled in the art, e.g., direct polymerization Or
monomers> gra~ting the acry].onitrile monomer mixture onto
the rubber backbone or physical admixtures Or 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 copolymer of
acrylonitrile and the same comonomer. The acryloni-trile-
based thermoplastics are frequently polymer blends Or a
grafted polymer and an ungrafted homopolymer.
Cornmercial examples Or nitrile resins include BAREX
21Q resin~ an acrylonitrile-based high nitrile resin con-
taining over 65% nitrile, and LOPAC ~ resin containing
3~
--112--
over 70% ni-trile, three-rourths of it derived from metha-
crylonitrile.
In order to better match the viscosity c,haracter;stics
of the thermoplastic engineering resin, the polyurethane
and the block copolymer, it is sometimes userul to first
blend the dissimilar thermoplastic engineering resin with
a viscosity modirier before blending the resulting mixture
with thepolyurethaneand 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 sensitivo to changos in temperature. ~xarTIpl(~s o~` suL~-
able viscosity modifiers include poly(2,6-dimethyl-1,4-
I phenylene)oxide and blends Or poly(2,6-dimethyl 1,4-phenyl-
ene)oxide with polystyrene.
The poly(phenylene oxides) included as possible
viscosity modifiers may be presented by the ~ollowing
formula:
:
~o}
wherein R1 is a monovalent substituent selected from the
group consisting of hydrogen, hydrocarbon radicals rree Or
a tertiary alpha-carbon atom, halohydrocarbon radicals
~ 3 ~
-~13-
having at least two carbon atoms between the halogen
atom and phenol nucleus and being free of a tertiary
alpha-carbon atom, hydrocarbonoxy radicals free o~
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., from 50 to 800 and
preferably 150 to 300. Included among these preferred
polymers are polymers having a molecular weight in the
range o~ between 6,ooo and 100,000, preferably 40,000.
,
Preferably~ the poly(phenylene oxide) is poly(2,6-di-
methyl-1,4-phenylene)oxide.
Commercially, the poly(phenylene oxide) is available
as a b]end with styrene resin. These blends typically
comprise between 25 and 50% by weight polystyrene units,
~B~ and are available under the ~ -- -
trade ~a~e NORYL thermoplastic resin. The preferred
molecular weight when employing a poly(phenylene oxide)~
polystyrene blend is between lO,000 and 50,000, preferably
around 30,000.
The amount of VlSCOSity modifier employed depends
primarily upon the difference between the viscosities of
the block copolymer and the engineering thermoplastic resin
at the temperature Tp. The amounts may range from 0 to lO0
r
_ 1I L~ _
parts by weight viscosity modlrier per lO0 parts by weight
engineering thermoplastic re.sin, preferably from lO to 50
parts by weight per lO0 parts of engineering thermoplastic
resin.
There are at least two methods (other than the absence
Or delamination) by which the presence of an interlocking
network can be shown. In one method~ an interlocking net-
work is shown when moulded or extruded objects made from
the blends of this lnvention are placed in a refluxing
solvent that quantitatively dissolves away the block co~
polymer and other soluble components, and the remaining
polymer structure (comprisirlg the thermoplastic engineer-
ing resin and ~l~ur~hane3 still has the shape and con-
tinuity of the moulded or extruded ob,ject and is intact
structurally without any crumbling or delamination, and
the re~luxing solvent carries no insoluble particulate
matter. If these criteria are ful~/illed, then both the
unextracted and extracted phase~ ~e 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 ~rom an insoluble matrix is highly unlikely.
Finally, interlocking networks must be present in order
to have simultaneous continuous phases. Also, confirmation
of the continuity Or the unextracted phase may be
5~ ;23~ ~
confirmed by microscopic examination. In the present
blends containing more than two components, the inter-
locking nature and continuity of each separate p~lase
may be established by selective extraction.
In the second method, a mechani.cal 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
' 15 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 ln parts
by welght (the total blend comprising 100 parts):
Parts by Preferred
;~ weight parts by
~ weight
:
20Dissimilar engineering
thermoplastic resin , 5 to 48 10 to 35
Block copolymer 4 to 40 8 to 20
The polyurethane is present in an amount greater
than the amount o~ the dissimilar engineering thermo-
-~l6~
plastic, i.e., the we;ght ratio of polyurethane to
dissimilar engineering thermop~astic is greater than
1:1. Accordingly, the amount of polyurethane may vary
from 30 parts by ~eight to 91 parts by weight, preferably
from 48 to 70 parts by weight. Note that the minimum
amount of block copolymer necessary to achieve these
blends may vary with the particular engineering thermo-
plastic.
The dissimilar engineering thermoplastic resin,
polyurethane and the block copolymer may be blended in
any manner that produces the interlocking network. ~or
example, the resin~ polyurethane and block copolymer may be
dissolved in a solvent common ~or all and coagulated by
admixing in a solvent in which none o~ the polymers are
soluble. fiut, a particularly use~ul procedure is to
intimately mix the polymers in the form of granules and/or
powder in a high shear mixer. "Intirnately mixing" means
to mix the polymers with sufficient mechanical shear and
~:
thermal energy to ensure that inter:Locking of the various
~~~
\~
::
_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 20:1 L/D ratio ~ -
and a compression ratio Or ~ 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 Or the
highest melting point polymer. In addition, as explained
more fully hereinafter, the processing temperature may
also be chosen so as to permit the isoviscous mixing
the polymers. The mixing or processing temperature may be
between 150 C and 400C, preferably between 230C and ~!
00C.
Another parameter that is important in melt blending
to ensure the formation Or interlocking networks is matching
the viscosities of the block copolymer,polyur~haneand the
20 ; dissimilar engineering thermoplastic resin (isoviscous
mixing) at the temperature and shear stress of the mixing
process. The hetter the interdispersion of the engineering
resin and ~lyurethaneinthe block copolymer network, the
better the chance for formation Or co-continuous inter
locking networks on subsequent cooling. Therefore, it has
been ~ound that when the block copolymer has a viscosity
~823~
n poise at temperature Tp and shear rate of 100 s 1,
it is preferred that the engineering thermoplastic resin
and/or the ~lyuretha~ nave such a viscosity at the temper-
ature ~p and a shear rate o~ 100 s that the ratio Or the
viscosity of the block copolymer divided by the viscosity
of the engineering thermoplastic and/or polyurethane be
between 0.2 and 4.0, preferably between o.8 and 1.2.
Accordingly, 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 ~p 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
15~ viscosity curves of two polymers dif~er at some of the
shear rates.
In some cases~ the order of mixing the polymers is
critical. Accordingly~ one may choose to mix the block
copolymer with the ~lyurethaneor other polymer first, and
then mix the resulting blend with the dissimilar engineer-
- ing thermoplastic, or one may sirnply 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 o~ the present invention. It is also
clear that the order of mixing can be employed in order
to better match the relative viscosities of the various
polyrner~.
_L19-
The block copolymer or block copolymer blend may be
selected to essentially match the viscosit~ of the
engineering thermoplastic resin and/or polyurethane.
Optionally, the block copolymer may be mixed with a
rubber compounding oil or supplemental resin as
described hereinafter to change the viscosity charac-
teristics of the block copolymer.
The particular physical properties of the block
copolymers are important in forming co continuous inter-
10 ~ locking networks. Specifically, the most preferred blockcopolymers when unblended do not melt in the ordinary
sense with increasing temperature, since the viscosity
~; of these polymers is highly non-Newtonian and tends to
increase without limit as zero shear stress is approached.
Further~ the viscosity of these block copolymers is also
relatively insensitive to temperature. This rheological
behaviour and inherent thermal stability of the ~lock co-
polymer ehhances its ability to retaln its network
(domain) structure in the melt so that when the various
20 ~ blends are made,interlocking and continuous networks are
formed.
- The viscosity behaviour of the engineering thermoplastic
resins, an(l~lyur~hanes on the other hand, is more sensitive
to temperature than that of the block copolymers. Ac
cordingly, it is often possible to select a processing
temperature Tp at which the v;scosities of the block
~ 2
-50-
copolymer and dissimilar engineering resin and/or poly-
urethc~eI~all within the required range necessary to form
interlocking networks. Optionally, a viscosity modifier~
as hereinabove describedg may first be blended with the
engineering thermoplastic resin or ~lyur~hane to achieve the
necessary viscosity matching.
The ~end of partially hydrogenated block copolymer,
~lyureth~Y~ and 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 Or oil that are compatible with
~the elastomeric polymer blocks of the block copolymer.
While oils of hi~her aromatics content; are satisfactory,
those petroleum-based white oils having low volatility and
less tharl 50% aromatics content as determined by the clay `
gel method (tentative ASTM method D 2007) are particularly
preferred. The oils pre~erably have an initial boiling
poînt above 260C.
The amount of oil employed may vary from O to 100 phr
20 ~ (phr = parts by weight per hundred partæ by weight of
block copolymer), preferably from 5 to 30 phrO
The blend Or partially hydrogenated block copolymer,
~lyuretha-e ~nd dissimilar engineering thermoplastic res;n
may be further compounded with a resin. The additional
res;n may be a flow promoting resin such as an alpha-
methylstyrene resin and an end-block plast;cizing resin.
~ ~ 8 23
-51-
Suitable end-block plasticizing resins include coumarone-
indene resins, vinyl toluene-alpha-methylstyrene co-
polymers, polyindene resins and low molecular weight
polystyrene resins.
The amount of additional resin may vary from 0 to
100 phr, preferably from 5 to 25 phr.
Further the composition may contain o-ther polymers,
fillers, reinforcements, anti-oxidants, stabllizers,
fire retardants~ anti-blocking agents and other rubber
and plastic compounding ingredients.
Examples of fillers that can be employed are mentioned
in the 1971-1972 Modern Plastics ~ncyclopedia, pages 2ll0-247.
Reinforcements are also useful in the present polymer
~ -.
blends. A reinforcement may be defined as the material that
~; 15~ is added to a resinous matrix to improve the strength of
~ ~ :
the polymer. Most Or these reinforcing materials are in-
organic or organic products Or high molecular weight.
Examples of reinforcements are glass fibres, asbestos 9
~ ~ boron ~ibres 9 carbon and graphite fibres, whiskers, quartz
and silica fibres, ceramlc fibres, metal fibres, natural
; organic ~ibres 9 and synthetic organic fibres. Especially
preferred are reinforced polymer blends containing 2 to
80 per cent by weight of glass fibres~ based on the total ~ -
weight of the resulting reinrorced blend.
The polymer blends of the invention can be employed
as meta] rep~acements and in those areas where high
perforrnance is necessary.
-~2 ~ 3~
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
ratio and a 3.8:1 compression ratio screw.
The various materials employed i.n the blends are
listed below:
l) Block copolymer - a selectively hydrogenated block
copolymer according to the invention having a
structure S-EB-S.
B 2) Oil - TIJF`FLO 6056 rubber extending oi].
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") - VQLOX ~ 310
resin.
7) Polycarbonate - MERLON ~ M-40 polycarbonate.
8~ Poly(ether sulphone) - 200 P.
9) Polyurethane - PELLETHANE ~ CPR having an apparent
crystalline melting point of 165C.
10) Polyacetal - DELRIN ~ 500.
11) Poly(acrylonitrile-co-styrene) - BAREX ~ 210.
12) Fluoropo].ymer - TEFZEL ~ 200 poly(vinylidene fluoride)
copolymer.
,~ ~,~ o ~ ,~
-53~
In all blends contairlirlg 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 a higher
and lower molecular weight was employed in some polymer
blends in order to better match the viscosity with the
polyurethane and/or other dissimilar engineering thermo-
plastic resin. Comparative blends not containing a block
copolymer were also prepared. However, these blends were
not easily mixed. For example, blend 114 comprising just
a polyurethane and Nylon 6 suffered from surging and a
~ ~ grainy appearance. In contrast, in each blend containing
a block copolymer, the polymer blend was easily mixed,
and the extrudate was homogeneous in appearance. Further~
in each blend containing a block copolymer~ the re-
sulting polyblend had the desired continuous, inter-
locking networks as established by the criteria herein-
above 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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