Note: Descriptions are shown in the official language in which they were submitted.
-2~ 3~
The invention relates to 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 conjugated
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 at least 80% of 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.
~;~ 20 For a particular 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 ~r
` 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~ :
successful in :Linl;tod cases, such as in the improvement
of irnpact resistance L'or thermoplastic resins, e.g.,
polystyrene, polypropylene and poly(vinyl chloride),
using special b]ending procedures or additives for this
purpose. However, in general, blending of thermoplastic
resins has not been a sueeessful route to enable one to
eombine into a single material the desirable individual
eharacteristics of two or more polymers. Instead, it has
often been found that such blending results in~'combining
the worst features of' eaeh with the result being a
material of sueh poor properties as not to be of any
praetieal or eommereial value. The reasons for this
failure are rather well understood and stem in part from
the faet that thermodynamies teaehes that most eombinations
of poly~ler pairs are not miscible, although a number of ~ ;~
notable exceptions are known~ More importantly, most
polymers adhere poorly to one another. As a result, the
interf'aces between component domains (a result of their
, . ~
immiscibility) represent areas of severe weakness in blends
and, therefore, provide natural flaws and cracks whieh
result in faclle meehanieal failure. Beeause of this,
'~ most polymer pairs are said to be "incompatible". In some
instances the term eompatibility is used synonymously
with miseibility, however, compatibility is used here in
a more general way that deseribes the ability to eombine
two polyrners together for benefieial results and may or
may not eonnote miseibility.
.
37~
One method wh:icll may be used to circumvent this
problem in polymer blends is to "compatibilize" the two
polymers by blending in a third component, often referred
to as a "compatibilizing 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 this characteristic,
this agent locates at the interface between components
; and greatly improves interphase adhesion and thér~fore
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 oP thermally reversible self-cross-linking.
~ Their action in the present invention is not that visualized
^i~ by the usual compatibilizing concept as evidenced by the
general ability of these materials to per~orm similarly
for a wide range of blend components which do not conform
to the solubility requirements of 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~ -
~ .
' ~:
:, ~.
.'
,, " . . ~
, :,. .. . . .. .
3~7glL
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 o:E 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) 4 to 40 parts by weight of the partially hydrogenated block copolymer;
(b) a polyamide having a number average molecular weight in excess of ~ :~
10,000,
(c) 5 to 48 parts by weight of at least one dissimilar engineering thermo-
plastic resin being selected from the group consisting of polyolefins,
thermolplastic polyesters, thermoplastic cellulosic esters, poly ~`
(arylethers), poly(aryl sulphones)~ polycarbonates, acetal resins,
thermoplastic polyurethanes, halogenated thermoplastics, and nitrile :~
~ resins,
:~ in which the weight ratio of the polyamide to the dissimilar engineering
thermoplastic resin is greater than 1:1 so as to form a polyblend wherein at . ~
least two oE the polymers form at least partial continuous interlocked net- ~ :works with each other.
The block copolymer of the invention effectively acts as a ~:
mechanical or structural stabili~er which interlocks
.~ .'.
'
'~
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~ .
--6--
the various polymer structure networks and prevents the
consequent separaticn of the po]ymers during processing
and their subsequent use. As defined more fully herein-
after, the resulting structure o~ the polyblend (short
for "polymer blend'l) 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 polymers 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. Further yet, ;-~
the disperse phase of one polymer may be dispersed in a
,' . ~.
:, :
.. : . ,
.. . . .
3~
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
; "d" signifies a disperse structure. Thus, the designation
''ACB'' means that p~ymer A is continuous with polymer B,
and the designation "BdC" means that polymer B is disperse
;~ 10 in polymer C, etc.
: c AcC BCC , ,.
d AcC BcC
. ACB AcC BdC
d AcC BCC
BdC AcB ACC
C A AcB ACC
,, CdB AcB ACC :,
Through practice of the invention~ it is possible to
,~,
prepare polyblends that possess a much improved balance of
~ 20 properties as compared to the individual properties of the
--~ separate polymers. For example, the invention permits the
-~ blending of a large amount of a polyamide with a smaller
- amount of a more expensive engineering thermoplastic resin,
such as poly(butylene terephthalate), resulting in a
polymer blend that retains much of the desirable properties
of the more expensive engineering thermoplastic resins at
a fraction of the cost.
-8~ ~ 7 ~
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. ~or example, as little as four parts by
weight of the block copolymer is suf`ficient to stabilize
a blend of 5 to 90 parts by weight polyamide with 90 to
5 parts by weight of a dissimilar engineering thermoplastic.
In addition, it is also surprising that the block co-
polymers are useful 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 composltion
according to the invention may have a variety of geometrical
-~ structure, since the invention does 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
.: . .. ..
9 ~ 3~7~ :~
the art. The structurc of the polymers 3 S determined by ~;
their metllods Or Ijo.Lymori~cltion. I~lor oxample, li.near
polymers result by sequential introduction of 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
difunctional coupling agent. Branched structures,on the
- other hand, may be obtained by the use of suitable ..
i coupling agents having a functionality with respec.k 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.
` 15 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 especially
~ 20 to the use of selectively hydrogenated polymers having
;:'f~ the~con~iguration before hydrogenation of the following
: typlcal species~
~ polystyrene-polybutadiene-polystyrene (SBS)
:- polystyrene-polyisoprene-polystyrene (SIS)
;~ 25 poly(alpha-methylstyrene)polybutadiene-
poly(alpha-methylstyrene) and
' ~ ~
:
.. ,.. , .. ,-- - ;
,~ , :
~, ."', ' : ,.~ ,
-lo- ~ 7~
poly(alpha-methylstyrenc)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 o~ the monomers charac-
terizing the polymer blocks. The polymer block A may
comprise homopolymers of' a monoalkenyl arene and co-
~' polymers Or a monoalkenyl arene with a conjugated diene
as long as the polymer blocks A individually pred-ominate`'' ,~
~` 10 in monoalkenyl arene units. The term "monoalkenyl arene"
'.' will be taken to include especially skyrene and its '
.~ analogues and homologues including alpha-methylstyrene
and ring-substituted styrenes, particularly ring-methyl-
ated styrenes. The preferred monoalkenyl arenes are '~
~s' 15 styrene and alpha-methylstyrene, and styrene is
--~ particularly pre~erred. The polymer blocks B may comprise
' homopolymers of a conjugated diene, such as butadiene or
isoprene, and copolymers of a conjugated diene with a
i monoalkenyl arene as long as the polymer blocks B pre-
dominate in conjugated diene uni~s. 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-conriguration. Thus,
when such a block is hydrogenated~ the resulting product
is, or resembles, a regular copolymer block of ethylene
and butene-1 (EB). I~ the conjugated diene employed is
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 alky.l compound with
nickel or cobalt carboxylates or alkoxides under such ~ ;
- conditions as to substantially completely hydrogenate
at least 80% of the aliphatic double bonds, while
hydrogenating no more than 25% of the alkenyl arene
aromatic double bonds. Preferred block copolymers are
those where at least 99% of the aliphàtic 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-
polymer 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
weight of f~om 5,000 to 125,000, preferably from 7,000
to 60,000, and at least one intermediate polymer block B
of a conjugated diene having a number 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.
7~
The proportion of the polymer blocks A of the mono-
alkenyl arene should be between 8 and 55% by weight of
the block copolymer, preferably between 10 and 30% by
weight.
~y polyamide is meant a condensation product whlch
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-
! izing 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 ~unctional
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
departures therefrom which are involved in conventional ~
: ,
: .
37~L
- . .
techniques for stabilizing the viscosity Or the resultant
polyamides
~ As examples of the said mono~aminomonocarboxylic acids
; or lactams thereof there may be mentioned those compounds ~ ;
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 of a lactam. As
particular examples of aminocarboxylic acids and lactams
there may be mentioned ~-aminocaproic acid, buty'rolactam,`''
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 o~ -
from 2 to 16, such as trimethylenediamine, tetramethylene-
diamine, pentamethylenediamine, octamethylenediamine,
decamethylenediamine~ dodecamethylenediamine, hexadeca-
methylenediamine, and especially hexamethylenediamine.
C-alkylated diamines, e.g., 2,2-dimethylpentamethylene-
diamine and 2~2,4-and 2, Ll, 4-trimethylhexamethylenediamine
are further examples. Other diamines which may be mentioned
as examples are aromatic diamines, e.g., p-pheny]ene-
diamine, 4,4'-diaminodiphenyl sulphone, 4,4'-diaminodi-
phenyl ether and 4,4'-diaminodiphenyl sulphone, 4,4'-di-
aminodiphenyl ether and 4,4'-diaminodiphenylmethane; and
cycloaliphatic diamines, for example diaminodicyclohexyl-
methane.
:
3~4
-14-
The said dicarboxylic acids may be aromatic, for ~;
example isophthalic and terephthalic acids. Preferred
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, octadecanedioicacid, ;
suberic acid, azelaic acid, undecanedioic acid, glutaric
acid, pimelic acid, and especially adipic acid. Oxalic
acid is also a preferred acid.
Specifically the following polyamides may be in-
corporated in the thermoplastic polymer blends of the
inventîon:
polyhexamethylene adipamide (nylon 6:6)
polypyrrolidone (nylon 4)
polycaprolactam (nylon 6)
polyheptolactam (nylon 7)
polycapryllactam (nylon 8)
polynonanolactam (nylon 9)
polyundecanolactam (nylon 11)
polydodecanolactam (nylon 12)
~ polyhexamethylene azelaiamide (nylon 6:9)
- polyhexamethylene sebacamide (nylon 6:10)
polyhexamethylene isophthalamide (nylon 6:iP)
polymetaxylylene~ipamide (nylon MXD:6)
polyamide of hexamethylene diamine and n-dodecanedioic
acid (nylon 6:12)
-15- 3L`~ 3~7~
; 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 ~nclude nylon 6,6/6, 11, 12, 6/3
and 6/12.
The number average molecular weights of the polyamides
should be above 10,000.
The term "dissimilar engineering thermoplastic resin"
refers to engineering thermoplastic resins different from
those encompassed by the polyamides present in the com-
positions according to the invention.
-16~ 7 ~
,~ ~
The term "engineering thermoplastic resin" encompasses ~
the various polymers found in the classes listed in Table A :
below and thereafter defined in the specification.
: TABLE A
1. Polyolefins
2. Thermoplastic polyesters
: 3. Poly(aryl ethers) and poly(aryl sulphones)
4. Polycarbonates
5. Acetal resins
6. Thermoplastic polyurethanes
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) o~ :
over 120C, preferably between 150C ~d 350C, and are
capable of forming a continuous network structure through ~ ~ :
a thermally reversible cross-linklng mechanism. Such
thermally reversible cross-linking mechanisms include
crystallites, polar aggregations, ionic aggregations,
: lamellae, or hydrogen bonding. ln a specific embodiment, -
where the viscosity of the 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
;,
37~
blend of engineering therrnoplastic resin with viscosity
modifiers to ~ may be between 0.2 and 4.o, preferably o.8
and 1.2. As used in the specification and claims, the
viscosity of the block copolymer, polyamide and the
thermoplastic engineering resin is the "me]t 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
transit~n 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 present in the compositions according
to the invention are crystalline or crystallizable. ~hey
may be homopolymers or copolymers and may be derived from
an alpha-olefin or l-olefin having 2 to 5 carbon atoms.
Examples of particular useful polyolefins include low- ;
density polyethylene, high-density polyethylene, iso-
tactic polypropylene, poly(l-butene), poly(4-methyl-1-
pentene), and copolymers of 4-methyl-1-pentene with
linear or branched alpha-olefins. A crystalline or
:
-18~ 3~ ~
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 of
the polyolefins is preferably above 10,000, more prefer-
ably above 50,000. In addition, it is preferred that the
apparent crystalline melting point is above 100C, prefer-
ably between 100C and 250C, and more preferably between
140C and 250C! The preparation of these various poly- ~-
olefins 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
"/
, : ~
,--'' ~.
"~
/~''"'' '
~'
37~ ~
-19-
kilograms per litre (kg/l) 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 of
between 0.90 kg/1 and 0.94 kg/l. The composition ac-
cording to the invention may contain a polyethylene havinga number average molecular weight of 50,000 to 500~000.
When a polypropylene is employed, it is the so- -
called isotactic polypropylene as opposed to atactic
polypropylene. The number average molecular weight-of thë
10polypropylene employed is in excess of 100,000. The poly-
propylene may be prepared using methods 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 crystallize rnore completely.
The preferred commercial polypropylenes are generally
.
;~;prepared using a solid, crystalline, hydrocarbon-in-
soluble catalyst made from a titanium trichloride com-
;position and an alumini~m 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-olefin as comonomer.
~ `
:
, I . ' , , , ~
: : , .. ~ .
-20 ~ 374
The poly(l-butene) preferably has an isotactic structure.
The catalysts used in preparing the poly(l-butene) are
preferably organo-metallic compounds commonly referred 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 guarantee rigorous exclusion of water even
` in trace amounts.
One very suitable polyolefin is poly(4-mekhyl-1-pentene). -
Poly(4-methyl-1-pentene) has an apparerlt 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
commercially manufactured by the alkali~metal catalyzed
dimerization of propylene. The homopolymerization of
4-methyl-1-pentene with Ziegler-Natta catalysts is described
in the Kirk-Othmer Enclopedia of Chemical Technology,
Supplement volume, pages 789-792 (second edition, 1~71).
However, the isotactic homopolymer of 4-methyl-1-pentenè
has certain technical defects, 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
~.
-21-
3~74
:
systems. These copolymers are described in the Xirk-
Othmer Encyclopedia of Chemical Technology, Supplement
volume, pages 792-907 (second edition, 1971), and are
available under the trade name 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.
,/ '
~ "-~
/'
/,/ '
'
` i
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-22~ 3~
One particularly userul ~roup 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
to methods well known in the art.
-~ Among the aromatic and aliphatic dicarboxylic aeids
- suitable for preparing polyesters are oxalic acid, malonie
aeid, sueeinie acid, glutaric acid, adipic acid, suberic
aeid, azelaic acid, sebaeie acid, terephthalic acid, iso- ~
phthalic acid, p-carboxyphenoacetie acid, p,p'~icarboxydiphenyl, ;;
p,p'-diearboxydiphenylsulphone, p-carboxyphenoxyacetic aeid,
p-earboxyphe~oxypropionic acid, p-carboxyphenoxybutyrie acid,
p~carboxyphenoxyvaleric aeid, p-earboxyphenoxyhexanoic aeid,
p,p'-diearboxydiphenylmethane, p,p diearboxydiphenylpropane, -
p,p'-diearboxydiphenyloctane, 3-alkyl-4~ earboxyethoxy)~
benzoic aeid, 2,6-naphthalene diearboxylie aeid, and 2,7-
naphthalene dicarboxylic acid. Mixtures of dicarboxylie
acids can also be employed. Terephthalie acid is particularly
preferred. -
~he glyeols suitable for preparing the polyesters
include straight-chain alkylene glyco:ls of 2 to 12 earbon
atoms, sueh as ethylene glycol, 1,3-propylene glycol,
1,6-hexylene glycol, 1,10-decamethylene glycol, and 1,12-
dodecamethylene glycol. Aromatic glyeols can be substituted
in whole or in part. Suitable aromatic dihydroxy compounds
inelude p-xylylene glyeol, pyroeateehol, resoreinol,
:. : ;~, .i
; -23- ~ 3~74
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(bukylene terephthalate). Poly(butylene terephthalate),
a crystalline copolymer3 may be formed by the polycondensation
of 1,4-butanediol and dimethyl terephthalake or terephthalic
acid, and has the generalized formula: ;
n
where n varies from 70 to 140. The average molecular weight
cf the poly(butylene terephthalake) preferably varies from
20,000 to 25,000. ~`
Commercially available poly(butylene terephthalate) is
ayailable under the trade name 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
.
;
-24- ~ 37~
, ,
and are well known. These materials include the solid
thermoplas-tic forms of cellulose nitrate, cellulose
acetate (e.~., cellulose diacetate, cellulose tri-
acetate), cellulose butyrate, cellulose acetate butyrate,
cellulose propionate, cellulose tridecanoate~ carboxy-
methyl cellulose, ethyl cellulose~ hydroxyethyl cellulose
and acetylated hydroxyethyl cellulose as described on
pages 25-28 of ~odern Plastics Encyclopedia, 1971-72, and
references listed therein. -
Another 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 from pivalolactone. Preferably, the poly-
ester is a pivalolactone homopolymer. Also included, however,
are the copolymers of pivalolactone with no more than 50 mol.%,
preferably not more 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 "beta-propiolactones" refers 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 of the
alkyl groups lndependently has from one to four carbon atoms.
~ .
: "' .
.. ... .. ..
`:
Examples of useful monomers are:
alpha-ethy]-alpha-methyl-beta-propiolactone,
alpha-methyl-alpha-isopropyl-beta-propiolactone,
alpha-ethyl-alpha-n-butyl-beta-propiolactone,
alpha-chloromethyl-alpha-methyl-beta-propio].actone,
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: ~;
r 0
t CH2 CH2 CH2 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 of re-
curring units having the formula:
(0 G 0 - G') - I
wherein Gisthe residuum of a dihydric phenol selected from
the group consisting o~:
' ' .
, ~, '"' ', ' '
374
_ ~ II
~ ~'
and - ::
- ~ -R
;
wherein R represents a bond between aromatic carbon atoms~
- O , S , - s-s-,or a divalent hydrocarbon radical : ~ .
having from 1 to 18 carbon atoms inclusive, and G' is the ~ :
residuum of a dibromo or di-iodobenzenoid compound
selected from the group consisting of: ..
/ ~ - IV
and
- R' = V ~ ~
:'
whereln R' represents a bond between aromatic carbon atoms, ~: -
. - O ~ S- - , - S- S - ,:or a divalent hydrocarbon
; 10 radical having from 1 to 18 carhon 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.
., ~
: ' j ,; ~
, , "
. , ~ ,. ~ , , . ;
, , ,, ~ , . , .: ::
-27~ 37~
Polyarylene polyethers of this type exh;bit excellent physical
properties as well as excellent thermal oxidative and
chemical stability. Commercial poly(aryl polyethers) are
available under the trade name ARYLON T ~ Polyaryl ethers,
having a melt temperature of between 280C and 310C.
Another group of useful engineering thermoplastic
resins include aromatic poly(sulphones) comprising re-
peating units of the formula:
...
Ar S02 -
:~ in which Ar is a bivalent aromatic radical and may vary
from unit to unit in the polDmer chain (so as to form co-
polymers of various kinds). Thermoplastic poly(sulphones)
generally have at least some units of the structure:
~ i
~/X~
,
,...... ' SO2
in which Z is oxygen or sulphur or the residue of an
aromatic diol, such as a 4,4' bisphenol. One example of
such a poly(sulphone) has repeating units of the formula: :
--0~\> SO2 : ~
,
, ; , -
~ 3~7~ :
-28-
another has repeating units of the formula:
~/ 3-S-~3-so2 ~ ~
; and others have repeating units of the formula:
~-SO2 C~ rC~
or copolymerized units in various proportions of the
formula:
-SOz- `~
and ~
~ ~--~--SO2--~
The thermoplastic poly~sulphones) may also have repeating
units having the formula:
Poly(ether sulphones) having repeating units of the
following structure:
'
:~ '
~ '
-29~ 37 4
~ 2~ ~
and poly(ether sulphones) having repeating units of the
fol].owing structure: -
so2 ~,~; o~3 c~3~oL
¦ ~ CH~ ~n
are also useful as engineering thermoplastic resins.
; The polycarbonates which may be present in the com-
:~ 5 positions according to the invention are of the general
~ formulae:
O
: "
(Ar- A-Ar- O- C- O)
n : :
and
. ,
(Ar- 0-~ - O) II
:~ 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, cycloalkylidene, :-:
alkylene, cycloalkylene, azo, imino, sulphur, oxygen,
sulphoxide or sulphone group, and n is at least two.
~, , , : :
~ 37 4
-30-
The preparation o~ 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 pyridine and bubbling phosgene into the
stirred solution at the desired rate. Tertiary 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 temperature. The reactions
generally utilize equimolar amounts of phosgene and di-
hydroxy reactants, however, the molar ratios can be varied
dependent upon the reaction condltions. ;~
In the formulae I and II mentioned, Ar and A are,
~ preferably, p-phenylene and isopropylidene, respectively.
- 15 This polycarbonate is prepared by reacting para,para'~so-
propylidenediphenol with phosgene and is sold under the ~-
trade mark LEXAN(R) and under the trade mark MERLON ~.
This commercial polycarbonate has a molecular weight of
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.
. . .
~ 3
-31-
The acetal resins which may be present in the com-
positions according to the invention include the high
molecular weight polyacetal homopolymers made by polymer-
izing formaldehyde or trioxane. These polyacetal homo-
polymers are commercially available under the trade nameDELRIN ~. A related polyether-type resin is available
under the trade name PENTON ~ and has the structure:
CH2Cl
_ -O CHz C CH2-
;~ CH2Cl
n
The acetal resin prepared from formaldehyde has a high
molecular weight and a structure typified by the following:
- H- o ( CH2- O- CH2- ) ~ H -
x
where terminal groups are derived from controlled amounts of
water and the x denotes a large (preferably 1500) number of -
formaldehyde uni~s linked in head-to-tail fashion. To in-
crease thermal and chemical resistance, terminal groups
are typically converted to esters or ethers.
Also included in the term polyacetal resins are the
polyacetal copolymers. These copolymers include block co-
polymers of formaldehyde with monomers or prepolymers of
other materials capable of providing active hydrogens,
-32~ i37~
such as alkylene glycols, polythio]s, vinyl acetate-
acrylic acid copolymers, or reduced butadiene/acrylonitrile
polymers.
Celanese has commercially available a copolymer of
formaldehyde and ethylene oxide under the trade name CELCON
that is useful in the blends of the present invention. These
copolymers typically have a structure comprising recurring
units having the formula:
~ :,
~~
wherein each R1 and R2 is selected from the group consisting
of hydrogeng 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 85% to 99.9% of the reourring
units.
Formaldehyde and trioxane can be copolymerized with
other aldehydes, cyclic ethers, vinyl compounds, ketenes a :. `-.
cyclic carbonates, epoxldes, isocyanates and ethers. These
compounds include ethylene oxide, 1,3-dioxolane, 1,3-dioxane,
1,3-dioxepene, epichlorohydrin, propylene oxide, isobutylene
oxide, and styrene oxide.
~'.
.
, .
.,. . . ~ , ,
Polyurethanesg otherwise known as isocyanate resins,
also can be employed as engineering thermoplastic resin as
long as they are thermoplastic as opposed to thermo-
setting. ~or example, polyurethanes formed from toluene
di-isocyanate (TDI) or diphenyl methane 4,4-di-isocyanate
(MDI) and a wide range of polyols, such as, polyoxyethylene
glycol~ polyoxypropylene glycol, hydroxy-terminated poly-
esters, polyoxyethylene-oxypropylene glycols are suitable.
These thermoplastic polyurethanes are available under
the trade name Q-THANE ~ and under the trade name
PELETHANE ~ CPR.
Another group of useful engineering thermoplastics
include 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 of the basic chemical formula
( -CF CF ) which contain 76% by weight fluorine.
These polymers are highly crystalline and have a crystalline
~34~ ~ 3
melting point o~ over 300C. Commercial PTFE is available ~ !
under the trade name TEFLON ~ and under the trade name
FLUON ~ . Polychlorotrifluoroethylene (PCTFR) and 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 of vinylidene fluoride. Poly~
(vinylidene fluoride) homopolymers are the partially
fluorinated polymers of the chemical formula ( CH2 - CF2 ~ .
These polymers are tough linear polymers with a crystalline
melting Point at 170C. Commercial homopolymer is available
under the trade name KYNAR ~ The term "poly(vinylidene
fluoride)" as used herein refers not only to the normally
solid homopolymers of vinylidene 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
example~ sym. dichlorodifluoroethylene, vinyl fluoride,
vinyl chloride, vinylidene chloride, perfluoropropene,per- ~ `
fluorobutadiene, chlorotrifluoroethylene, trichloroethylene
and tetrafluoroethylene.
Another useful group of halogenated thermoplastics
include homo~olymers and copolymers derived from vinylidene
chloride. Crystalline vinylidene chloride copolymers are
~'
.. , .. ,.. ,............... ... , . . . ~
-35- ~ 4~7 ~
especially proLorred. Tlle normally crystalline vinylidene
chloride copolymers that are useful in the present in-
vention are those containing at least 70% by weight of
vinylidene chloride together with 30% or less of a co-
polymerizable monoethylenic monomer. Exemplary of suchmonomers are vinyl chloride, vinyl acetate, vinyl
propionate, acrylonitrile, alkyl and aralkyl acrylates
having alkyl and aralkyl groups of up to about 8 carbon
atoms, acrylic acid, acrylamide, vinyl alkyl ethers,
vinyl alkyl ketones, acrolein, allyl ethers and othe~s,
butadiene and chloropropene. Known ternary compositions
also may be employed advantageously. Representative of
such polymers are those composed of at least 70% by weight
of vinylidene chloride with the remainder made up of, for
example, acrolein and vinyl chloride, acrylic acid and
acrylonitrile, a]kyl acrylates and a:lkyl methacrylates,
acrylonitrile and butadiene, acrylon:itrile 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 chloride and vinyl ethers and vinyl chloride.
Quaternary polymers of similar monomeric composition will
also be known. Particularly useful for the purposes ~
the present invention arc copolymers of from 70 to 95% by
weight vinylidene chloride with the balance being vinyl
chloride. Such copolymers may contain conventional amounts
,'` :
.~ .
. . .
"
. , . . ',
36 1~37~
and types of plasticizers, stabilizers, nucleators and
extrusion aids. Further, blends of two or more of such
norrnally crystalline vinylidene chloride polymers may
be used as well as blends comprising 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 useful as engineering thermoplastic
resin are those thermoplastic materials having an alpha,beta- -;
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
CE2 = C - CN
R ;
where R lS hydrogen, an alkyl group having from 1 to 4
carbon atoms, or a halogen. Such compounds include acrylo-
nitrile, alpha-bromoacrylonitrile, alpha-fluoroacrylo-
20~ nitrlle, methacrylonitrile and ethacrylonitrile. The most
preferred 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
, . I .
.` ;',
,''
,~
'
' ~" '' ' , : , :
-37~ '3~ 4
structure is a random copolymer, r~redominantly acrylonitrile
or methacrylonitrile. The most common example is a
styrene-acrylonitrile copolymer. Block copolymers Or
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 from
2 to 8 carbon atoms, e.g., ethylene, propylene, iso- ~
butylene, butene-1, pentene-1, and their halogen and ~ -
aliphatic substituted derivatives as represented by vinyl
chloride and vinylidene chloride; monovinylidene aromatic
hydrocarbon monomers of the general formula~
` ~1 :,
H2C ---C~
wherein R1 is hydrogen, chlorine or methyl and R2 is 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., styrene, alpha-
methyl styrene, vinyl toluene, alpha-chlorostyrene, ortho-
chlorostyrene~ para-chlorostyrene, meta-chlorostyrene,
:,
ortho-methy] styrene, para-methyl styrene, ethyl styrene,
.",~ ~.
:........................................................................ ..
i.~
~i .
:' .
'. ' :: ~
. . .
.: , ,.
-38-
isopropyl styrene, dich~ll)rostyrene and vinyl naphthalene.
Especially preferred cc)monomers are isobutylene and styrene.
Another group of comonomers are vinyl ester monomers
of the general formula:
H
3 ,
; C=O
~ R3
~ 5 wherein R3 is selected from the group comprising hydrogen,
alkyl groups of from 1 to 10 carbon atoms, aryl groups of
from 6 ko 10 carbon atoms including the carbon atoms in
ring-substituted alkyl substituentsj e.g., vinyl formate,
; vinyl acetate, vinyl propionate and vinyl benzoate.
Similar to the foregoing and also useful are the
vinyl ether monomers of the general formula: ~-
; 2
wherein RLI 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 linkages9 and may
also contain other substituents, such as halogen and
carbonyl. Examples of these monomeric vinyl ethers include
vinyl methyl ether, vinyl ethyl ether, vinyl n-butyl ether,
vinyl 2-chloroethyl ether, vinyl phenyl ether, vinyl isc-
., - ':
~' ~
:; '
39 ~ 374
butyl ether, vinyl cyclohoxyl ether, p-butyl cyelohexyl
ether, vinyl ether or p-chlorophenyl glycol.
Other comonomers are those comonomers which contain
a mono- or dinitrile function. Examples of these include
methylene glutaronitrile, (2,4-dicyanobutene-1)~ vinyl-
idene cyanide, crotonitrile, fumarodinitrile, maleodi-
nitrile.
Other comonomers inelude the esters of olefinieally
unsaturated earboxylie aeids,preferably the lower al~yl
esters of alpha,beta-olefinieally unsaturated earboxylie
aeids and more preferred the esters having the strueture:
CH2 C--COOR
.
wherein Rl is hydrogen, an alkyl group having from 1 to 4
earbon atoms, or a halogen and R2 is an alkyl group having
from 1 to 2 earbon atoms. Compounds of this type inelude
methyl aerylate, ethyl aerylate, methyl methaerylate,
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 have 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,
" ::
' ,:
~4~
viny] acetate, or methyl methacrylate, for example. The
backbone may consist of one, two, three, or more com-
ponentsa and the grafted branches may be composed of one,
two, three or more comonomers.
-~ 5 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
1~ 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 which 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 copolymer 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 ~AREX
210 resin, an acrylonitrile-based high nitrile resin con-
~ taining over 65% nitrile, and LOPAC ~ resin containing
.: '
~ ;
.
,
-41~ 7~
over 70% nitrile, thr(?e-l`ourt~ls o~ it derived f'rom metha-
crylonitrile.
In order to better match the viscosity characteristics
of the thermoplastic engineering resin~ the polyamide
and the block copolymer, it is sometimes useful to first
blend the dissimilar thermoplastic engineering resin with
a viscosity modifier bef'ore blending the resulting mixture
with the polya~'ide and block copolymer. Suitable viscosity
modifiers have a relatively high viscosity, a melt témper- ¦~
ature of over 230 C, and possess a viscosity that is not
very sensitive to changes in temperature. Examples of suit- "
able viscosity modifiers include poly(2,6-dimethyl-1,4-
phenylene)oxide and blends of 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 following
formula: ~ ~
R1 ~ -
~ l
_ O-
;~ L 1 ~m
~
wherein R1 is a monovalent substituent selected from the
group consisting Or hydrogen, hydrocarbon radicals ~ree of
' 20 a tertiary alpha-carbon atom, halohydrocarbon radicals
"~
:. ~ .
-42-
having at least two carbon atoms between the halogen
atom and phenol nucleus and being free of a tertlary
alpha-carbon atom, hydrocarbonoxy radicals free of
aliphatic, tertiary alpha-carbon atoms, and halohydro- -
carbonoxy radicals having at least two carbon atoms -
between the halogen atom and phenol nucleus and being free
of an aliphatic, tertiary alpha-carbon atom, R'1 is the
same as R1 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. IncIuded 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-
methyl-1,4-phenylene)oxide.
; 15 Commercially, the poly(phenylene oxide) is available
as a blend with styrene resln. These blends typically
comprise between 25 and 50% by weight polystyrene units, ;
and are available from General Electric Company under the
; trade name NORYL ~ thermoplastic resin. The preferred
~20 ~ molecular weight when employing a poly(phenylene oxide)/
polystyrene blend is between 10,000 and 50,000, preferably
"~ around 30,000.
The amount of viscosity modifier employed depends
primarily upon the difference between the viscosities of
25 the block copolymer and the engineering thermoplastic resin
at the temperature-Tp. The amounts may range from O to 100
`
:: :
`
' ~
~: . , , , ., , , ~
,, , ~
_43~ '37~ :
parts by weight viscosity modifier per 100 parts by weight
engineering thermoplastic resin, 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 method, 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 components, and the remaining
polymer structure (com~rising the thermoplastic engineer-
ing resin and polyamide) 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 fulfilled, then both the
unextracted and extracted phases a~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 -i
phase from an insoluble matrix is highly unlikely.
` Finallys interlocking networks must be present in order
to have simultaneous continuous phases. Also, confirmation
-~ of the continuity of the unextracted phase may be ~-
,'. ,'
,;. .
:'
, .
44 ~ qh~3~ ~
confirmed 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. For example, in a
blend containing block copolymer, polypropylene and nylon 6, -
the block copolymers may be first extracted by refluxing
toluene, leaving the polypropylene and nylon phases. Then
the nylon may be extracted by hydrochloric acid leaving the
polypropylene phase. Alternatively, the nylon may be extracted
first and then the block copolymer. Phase continuity and
the interconnecting of holes may be microscopically examined -
after each extraction.
In the second method, a meehanical 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 o~ 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 ofthe polymers are presented below in parts
- by weight (the total blend comprising 100 parts):
,
-45- ~ 37 ~
Parts Preferred
by weight parts by
_ weight
Dissimilar engineering
thermoplastic resin 5 to 48 10 to 35
5Block copolymer 4 to 40 8 to 20
The polyamide is present in an amount greater than
the amount of the dissimilar engineering thermoplastic,
i.e., the weight ratio of polyamide to dissimilar engineer-
ing thermoplastic is greater than 1:1. Accordingly, the
amount of polyamide may vary from 30 parts by weight 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 thermoplastic.
;~ 15 The dissimilar engineerlng thermoplastic resin,
polyamide and the block copolymer may be blended in any
,''''3'~manner that produces the interlocking network. For
example, the resin, polyamide 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 useful 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 mechanical shear and
thermal energy to ensure that interlocking of the various
,
~ 37 4
-46-
networks is achieved. Intimate mixing is typically
achieved by employing h:igh shear extrusion compounding
machines9 such as twin screw compounding extruders and
thermoplastic extruders having at least a 20:1 I./D ratio ~; -
and a compression ratio of 3 or L~
The mixing or processing temperature (Tp) is selected
in accordance with the particular polymers to be blended.
~or example, when melt blending the polymers instead of -
solution blendinga it will be necessary to selêct a
processing temperature above the melting point of the ~-.
highest melting point polymer. In addition, as explained
more fully hereinafter, the processing tempe~ature may -~
also be chosen so as to permit the isoviscous mixing of
the polymers. The mixing or processing temperature may be
between 150 C and 400C, pre~erably between 230C and
300C.
l Another parameter that is important in melt blending
-~ to ensure the rOrmation of interlocklng networks is matching
the viscosities of the block copolymer, polyamide and the
dissimilar engineering thermoplastic resin (isoviscous
~` mixing) at the temperature and shear stress of the mixing
~` process. The better the interdispersion of the engineering
resin and polyamide in the block copolymer network, the
better the chance for formation of co-continuous inter-
locking networks on subsequent cooling. Therefore, it has
been found that when the block copolymer has a viscosity
... . . . .......... ... ... ....... ... . ........... ..... . . . . ..
~374
-47-
~ poise at temperature Tp and shear rate of 100 s 1,
it is preferred that the engineering thermoplastic resin
and/or the polyamide have such a viscosity at the temper-
ature Tp and a shear rate of 100 s 1 that the ratio of the
viscosity of the block copolymer divided by the viscosity
of the engineering thermoplastic and/or polyamide be
between 0.2 and 4.0, preferably between o.8 and 1.2.
Accordinglyg 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
. . .
` 15 viscosity curves of two polymers differ 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 polyamide or other polymer first, and
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 of mixing can be employed in order
to better match the relative viscosities of the various
polymers.
3~4
-48-
The block co~)olymer or block copolymer blend may be
selected to essentially match the viscosity of the
engineering thermoplastic resin and/or polyamide
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 block
copolymers 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.
~urther, the viscosity of these block copolymers is also
relatively insensitive to temperature. This rheological
behavlour and inherent thermal stability o~ the block co-
polymer e~hances its ability to retain its network
(domain) structure in the melt so that when the various
2~ blends are made,interlocking and continuous networks are
~ormed.
The viscosity behaviour of the engineering thermoplastic
resins, and polyamides 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 viscosities of the block
' ,
li37~
-49
coPolymer and dissimilar engineering resin and/or poly~
amide fall within the required range necessary to form
interlocking networks. Optionally, a viscosity modifier,
as hereinabove described, may first be blended with the
engineering thermoplastic resin or polyamide to achieve the
necessary viscosity matching.
The blend of partially hydrogenated block copolymer, ~ ~
polyamide 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 of oil that are compatible w1th
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 from 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~
polyamide and dissimilar 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.
~ 37
_50_
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 other polymers,
fillers, reinforcements, anti-oxidants, stabilizers,
fire retardants, anti-blocking agents and other r~bber
and plastic compounding ingredients.
Examples of fillers that can be employed are mentioned
in the 1971-1972 Modern Plastics Encyclopedia, pages 2L~0-247.
- Reinforcements are also useful in the present polymer
blends. A reinforcement may be defined as the material that
is added to a resinous matrix to impro~e the strength of
the polymer. Most 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
80 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.
3~7~
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 in the blends are
listed below:
1) Block copolymer - a selectively hydrogenated block
copolymer according to the invention having a
structure S-EB-S and block molecular weights of
7,500-38,000-7,500.
2) Oil - TUFFLO~ 6056 rubber extending oil.
3) Nylon 6 - PLASKO ~ 8207 polyamide~
4) Nylon 6-12 - ZYTEL~ 158 polyamide.
5) Polypropylene - an essentially isotactic polypropylene
having a melt flow index of 5 (230C/2.16 kg).
6) Poly(butylene terephthalate) ("PBT") - VALO ~ 310
resin.
7) Polycarbonate - MERLO ~ M-40 polycarbonate.
20 8~ Poly(ether sulphone) - 200 P.
9) Polyurethane - PELLETHAN ~ CPR.
10) Polyacetal - DELRI ~ 500.
11) Poly(acrylonitrile-co-styrene) ~ BAREX~ 210.
12) Fluoropolymer - TEFZEL~ 200 poly(vinylidene fluoride) ~-
copolymer.
, .
, . .. : ,. . :,
- 5 ~ 37~
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 present invention. In each case, the polymer blend
was easily mixed, and the extrudate was homogeneous in
appearance. Further, in each case, the resulting poly~
blend had the deslred continuous, interlocking networks
as established by the criteria hereinabove descrlbed.
The compositions, conditions and test results are
presented below in Table I. The compositions are listed
in percent by weigh~.
.
~ '
~:
:'~
.~$:~tl!3~7~
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_ _ ____ _
, ~ ~ ~ oo o o .
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': ~ : ~ ~ U~ o o : :: , l
`~ ~L~
~, :
T OD _ ~ _ ~ er _ _ _ _ r~ ~
~1 ~ a~, Lr~ _ ul ___ _ _ o
~ C N : V : td i ~ ~J O ~ V
- Z O ~9 ~1 O Q Pi Q ~_ ~ ~d ~ o - p ~ h : ~
~ O ~ ~ ~: P~ _ ~ _ ~ ~ _~ S~ X ~0~
~ ~ o æ' ~ ~ o ~ P~ ~ Q P~ ~ O
.. '~ '~
.' ,. .
. ~ _53--
3t7~ ~
~ N N -------- I~ -- N ~ ~
t~ u~ ~n r r~) ~r : -
~ r. r,~J r~ r,~l r
_ o Lr ~ _ _ _ _
o o r,~J ~ ~
I--I ~r) Lf~ __ _ _ N
o o-- r~ r~ .___ r
~1 ~1 ~ r.~l r.~l ;;
o o-- r~l ~ __ _ _ ~
,1 r~ In . ~1 r.~l ^
r~ o _ I~ _ _ _ rr) _ --
o r~ r,~l r~ ~ ~ `
r~ o _ ~ _ _ In o . '.
o o r.~l I~ r~
~ ~1 O-1`-- __ _ ~ O ~
C~ ,_ _ _ _ __ __ _ r~l N ' ~'
M~ lol ~ ~ N~
_ o _ ~ _ _ ------ r~------ -- ~:
cn O -- O Ir~ N _ ~ _
._ ~ C _ N _ _ ~ _ _ U~ .
cn In r~ r,~l r.~l ~:
_ S _ _ l _ - _- O~ ~.
~uo â) o ~ ~rl S~ S
I s,, ~ ~ ~ ul a~
a)a) td ~ ~ O ~ ~ ~ a
O r,~J ~1~1~1 1~: S~ t~ ~1 ~1 u~ ~ a) S~
. l ~1 :~~ ~ O a) ~: ~d ~ I ~ ~ :~ ::
O O l ~ ~ ~ Q ~: ~) ~ S~ O O ~ .
z; t) ~ ~9 o::~ ~ s~ ~ a) a) o o ~ (d
~1 ~ ~ 1:~ SJ~_ Q I ') a) a) S-l (15 a) O ~ al ~
~: O O O ~1~1 a) ~, ~ I ~ ~-~r-l ~1 ~
a) o ~ ~ ~ s~ ~ ~1 o ~ ~ ~ J ~ ~c r
~ ~ .~ ~ ~ o o a) o o ~ o o o s~ ~ ~1 a)
m ~ ~ z z; ~ ~4 ~ ~ ~ Q ~ _B:L ~ ~1 ~
.,
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~55~ ~ 3
Illustrative Example II
~,~
100 parts by weight of the blend number 52 from ~ -
Illustrative Example I was reinforced with 65.6 parts by ~ -
weight PP~ 0.625 cm glass fi.bre strands by melt blending
! 5the glass fibres with the polymer blend in the extruder ~ -
at a temperature of' 240C. The resulting composition had
the following properties:
Young's modulus x 103, kPa 7431
Yieldg kPa 50188 ;.; -
Tensile at break, kPa 50188
: Ultimate elongation at break, % 1.58 ~-
Flex modulus x 103, kPa6081 -
Notched Izod impact strength,
J/cm o.69 ~ -
Illustrative Example III
Glass reinforced blends similar to the one prepared ;;~
in Illustrative Example II were prepared, except that all ~
: four major components plus the glass fibre were dry blended : ~:
;.
together at the same time i.nstead of first preparing the :~
polyblend and then adding the glass fibres.
The various compositions, conditions and test results .
-:
: are presented below in:Table II. In all cases, the resulting :~
polyblends possessed the desired;interlocking network
structure.
:
-56- ~ 374
;:
TABLE II
Blend No. 56 58
Component~ parts by weight
Block copolymer 3.5 6.8
Oil o 7 1.7
Nylon 6 15.0
Nylon 6-12 - 26.1 ;
Polypropylene 41.0 26.1
Glass fibres 39.8 39.2 -
; 10 Extrusion temperature,aC 240 240
Properties
~ j . .
Young's modulus x 10~
kPa 7487 5522 ~::
Yield, kPa 51498 52877 ~ ~
Tensile at break, kPa 51498 52877 : .
Ult:imate elongation
at break, % 1.21 1.78
Flex modulus x 103, -
kPa 5943 ~ 4957
~Notched Izod lmpact
strength, J/cm0.72 ~ o.63
.
~ - Illustrative Example IV ~ :
..
Vari~ous polymer blends contain1ng Nylon 6:were:prepared. ~ :~
This Example shows that the presence of the block copolymer
: 25 is essential for the success of the invention. All blends ~:
; were prepared by mixing on the extruder at 230C. ~he
''
_57~ 3~ 4
compositions are presented below in Table III. (Note, some
blends are also presented in Table I).
Blends 18, 12 and 41 are presented for comparison
purposes and contain either Nylon 6 by itself or Nylon 6
with polypropylene, while blends 14-17 and 43 reveal
blends of the present invention having at least two
continuous interlocking networks.
TABLE III
Blend No. 18 12 14 1516; 17 41 43 -
~lO Component, parts
by weight
. ,;
Block copolymer - - 4.2 8.3 12.5 25.0 - 25.5
Oil - _ o.8 1.7 2.5 s.o - 11.5
Nylon 6 loo 50 47 - 5 4542.5 35 50 35
PBT ~- - - - ~ ~ 50 35
Polypropylene - 50 47.5 45 42.5 35 ~ - -
Toluene solubles
Expected (%w) O 0 5 lo 15 30 o 30
Found (%w)1.2 3.1 4.9 10.7 14.0 28.3 o.4 29.2 `-~
HCl solubles ~ .
Expected (%w) 100 50 47.5 45.o 42.5 35 50 35
Found (%w) 98.8 17.8 45.o 42.9 47.6 28.6 2.3 35.3
,
The presence (or absencej of a continuous interlocking
network was examined by a selective extraction technique.
In this technique, the polymer blend is subjected to a
16-hour Soxhlet extract;on with hot refluxing toluene.
::
.. . . . . ...
5 ~ 3~
Ideally, the hot toluene should extract the block co-
polymer and oil, but should not dissolve the PBT or
nylon. Then the unextracted portion of the blend is placed
in a vessel contalning 6 molar hydrochloric acid (HCl)
and shaken for about 20 hours at room temperature. The
HCl should dissolve the Nylon 6, but not the poly-
propylene or PBT. The unextracted portion of the blend
after each extraction is weighed and the weight loss
compared with the expected values.
In blend 18, 1.2% of the Nylon 6 was solublë in hot
toluene compared to an expected 0% (well within the
accuracy of the technique). The remainder of the polymer
completely dissolved in the HCl.
Extraction of blends 12 and 41 not containing any of
the claimed block copolymer reveals the absence of con-
tinuous interlocking networks. In blend 12, 3.1% of the ~
blend was soluble in hot toluene compared to an expected ;;
0%, also well within the accuracy of the technique. How-
ever~ only 17.8~ of the extracted blend was soluble in
HCl compared to an expected 50%. This indicates that a
large portion of nylon was so encapsulated in the poly-
propylene as to be inaccessible to the HCl, i.e., there
was no continuous network of nylon that would be accessible
to the HCl. In blend 41, 0.4% of the blend of PBT and
Nylon 6 was soluble in hot toluene compared to a
theoretical 0%. However, only 2.3% of the extracted blend
-5~ i374
was soluble in HC1 compared to an expected 50%, ln-
dicating a lack of a continuous interlocking network
since apparently only a small portion of nylon was
accessible to the HCl.
Contrary to the results in blends 12 and 41, the
extraction technique reveals the presence of continuous
interlocking networks in blends 14-17 and 43, wherein
the block copolymer of the instant invention is employed.
For example, in blend 14, 4.2 parts by weight block co-
polymer are employed. The toluene extracted 4.9%~
compared to an expected 5%, and most significantly,
the HCl extracted 47.5% compared to an expected 45.0%,
all within the accuracy of the technique. This indicates
that the nylon was present as a continuous network since
apparently all the nylon was accessible to the HCl as
would be expected from a completely connected phase. :
Similar results are shown for the other polymer blends
prepared according to the present invention.
Comparative Example I
In the comparative Example I~ various blends of
Nylon 6 and other engineering thermoplastics were
prepared in the absence~of the present block copolymer.
The various blends are presented below in Table IV
along with individual remarks concerning the blend.
.
.,
, ~
.:. ' ,; . ::'
-60~ 3~
TABLE IV ~ ~-
Blend Engineering Weight Processing Comments
No. thermoplastic ratio of temperature
resin (Eng. Nylon 6 (C)
th.) to Eng.
Th.
:
12 Polypropylene 1:1 235 Grainy appearance
41 PBT 1:1 240 Weak melt
hand take off
68 PBT 1:1 265 Not strandable ~
110 Polycarbonate 1:3 270 Melt fracture, ~ ;
extreme die
swell surging
114 Polyurethane 3:1 240 Surging, grainy
115 Polyacetal 3:1 ~ 230 Die swell,
surging~
melt fracture
.
116 PBT 3:1 245 Die swell,
slight melt
fracture
~; ~ 117 Polycarbonate 3:1 270 Surging, gross
melt fracture,
die swell
118 Poly(ether 3:1 300 Slight surging,
sulphonej strand dimpling
(ca~itation)
slight melt
fracture
-61~ 3'~
TABLE IV (cont'd)
Blend Engineering Weight Processing Comments
No. thermoplastic ratio of temperature
resin (Eng. Nylon 6(C) :~
th.) to Eng.
Th.
__
121 Fluoropolymer 3:1 300 Surging extreme,
knobby gross
., . ,~
profile ~:~
176 Poly(acrylo- 1 3 250 No comparison
:~ ~ nitrile-co- made ; .
~ styrene)
:
"~ ~
:
.
: ,:,
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.
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