Document pBKaeDrE5p4o3Kwk41pXKvwwB
United States Patent [19]
Froix
[ii] Patent Number:
4,489,190
[45] Date of Patent: Dec. 18, 1984
[54] BLEND OF POLYALKYLENE TEREPHTHALATE AND WHOLLY AROMATIC POLYESTER
[75] Inventor: Michael F. Froix, Menlo Park, Calif.
[73] Assignee: Celanese Corporation,New York, N.Y.
[21] Appl. No.: 158,547
[22] Filed:
Jun. 11,1980
[51] Int. Q.3 ............................................ C08L 67/00 [52] U.S. Cl................................. 524/539; 264/176 F;
524/443; 524/451; 524/452; 524/494; 524/495; 525/165; 525/444
[58] Field of Search...................... 525/444; 260/40 R
[56] References Cited
U.S. PATENT DOCUMENTS
3,546,320 12/1970 Duling et al........................... 525/444 4,184,996 1/1980 Calundann ......................... 260/40 R 4,238,599 12/1980 Langley et al......................... 528/193
FOREIGN PATENT DOCUMENTS
2008598 6/1979 United Kingdom ................ 525/444
Primary Examiner--Jacob Ziegler Attorney, Agent, or Firm--Burns, Doane, Swecker & Mathis
[57] ABSTRACT
A polymer blend which is capable of exhibiting an ani sotropic melt phase and the ability to form shaped arti cles having satisfactory mechanical properties is pro vided. The polymer blend comprises approximately 5 to approximately 75 percent by weight, based upon the total weight of the blend, of a polyalkylene terephthalate wherein the alkylene units contain 2 to 5 carbon atoms and approximately 25 to approximately 95 per cent by weight, based upon the total weight of the blend, of a melt processable wholly aromatic polyester which is capable of forming an anisotropic melt phase apart from the blend.
34 Claims, No Drawings
4,489,190
12
be expected to exhibit a significant reduction in mechan
BLEND OF POLYALKYLENE TEREPHTHALATE ical properties. Accordingly, there has been little impe
AND WHOLLY AROMATIC POLYESTER
tus to form such blends, particularly for use in applica
tions where mechanical properties are of importance.
BACKGROUND OF THE INVENTION
5 U.K. Published Patent Application No. 2,008,598
The present invention relates to a blend of polyalkyl- discloses a polymer composition comprising 20 percent
ene terephthalate and melt processable wholly aromatic or less, based upon the total weight of polymeric mate
polyester. The characteristics and properties of such a rial, of a first rigid polymeric material with the balance
blend differ significantly from those expected in light of being a second polymeric material composed substan
observations of the properties of ordinary mixtures and 10 tially of flexible molecular chains. The first polymeric
of most polymeric blends.
material is dispersed in the second polymeric material in
When a blend or mixture is prepared from two or a microscopic region of 1 fim. or less. Foreign counter
more ordinary, non-polymeric materials, a random dis parts of this application include Japan No. 54065747,
tribution of the molecules of the components is ob French No. 2407956, and West German No. 2847782. tained. This random distribution provides complete 15 It is an object of the present invention to provide a
mixing without the formation of groups or clusters of blend of polyalkylene terephthalate and wholly aro
the molecules of any one component. Such a mixture is matic polyster which exhibits satisfactory mechanical
expected to follow the "Rule of Mixtures." The Rule of properties, such as tensile strength, tensile modulus,
Mixtures predicts the numerical value of properties, flexural strength, flexural modulus, impact strength, and such as tensile and flexural strengths and tensile and 20 heat deflection temperature.
flexural moduli, of a blend to be the weighted average
It is also an object of the present invention to provide
of the numerical values of the properties of the compo a blend of polyalkene terephthalate and wholly aro
nents.
matic polyester which exhibits, within at least some
A discussion of the Rule of Mixtures can be found in compositional ranges, mechanical properties, such as
the book Predicting the Properties of Mixtures: Mixture 25 tensile and flexural properties, which are improved
Rules in Science and Engineering, by Lawrence E. Niel over those of each component alone.
sen, Marcel Dekker Inc. (New York).
It is also an object of the present invention to provide
Further information with regard to the Rule of Mix a blend of polyalkylene terephthalate and wholly aro
tures can be found on pages 395, 436, 465, 492 and 500 of Volume 2 of Mechanical Properties of Polymers and Composites, by Lawrence E. Nielsen, Marcel Dekker Inc. (New York: 1974). As stated therein, mixtures of a polymer matrix with a fibrous reinforcing agent, a rib
30
matic polyester which exhibits no significant reduction in mechanical properties, such as tensile and flexural properties, as compared to the weighted average of the mechanical properties of the individual components.
bon-shaped filler, or a rod-shaped filler are known to
It is also an object of the present invention to provide
follow the Rule of Mixtures. The above-cited reference 35 a blend of polyalkylene terephthalate and wholly aro
further discloses that mixtures of phase inverted iso matic polyester which exhibits a high degree of anisot
tropic interpenetrating polymer networks, such as a ropy and shear sensitivity in the melt.
phase inverted network of polystyrene and polybutadi
It is also an object of the present invention to provide
ene, are also known to follow the Rule of Mixtures.
a blend of polyalkylene terephthalate and wholly aro
Mixtures of most chemically distinct polymeric mate 40 matic polyester which, by virtue of the inclusion of a
rials have been found to deviate from the behaviour of relatively less expensive component, is less expensive
ordinary mixtures as characterized by the Rule of Mix than the relatively more expensive component alone
tures. The sheer size of polymeric chains restricts mix and which exhibits no significant reduction in mechani
ing of the components and leads to the formation of cal properties.
domains or clusters of molecules of the individual com 45 These and other objects as well as the scope, nature,
ponents. Thus, it can be said that most chemically dis and utilization of the present invention will be apparent
tinct polymeric materials tend to be incompatible in from the following description and appended claims.
mixtures, exhibiting a tendency to separate into phases. There exists a boundary between the domains of the
SUMMARY OF THE INVENTION
component polymers, and articles made from such a 50 The present invention provides a polymer blend
blend would be expected to exhibit failure at the bound which is capable of exhibiting an anisotropic melt phase
ary when placed under stress. In general, then, the me and the ability to form shaped articles having satisfac
chanical properties of the product are commonly re tory mechanical properties. The blend comprises:
duced rather than enhanced. Specific properties which
(a) approximately 5 to approximately 75 percent by
may be thus affected include tensile strength, tensile 55 weight, based upon the total weight of components (a)
modulus, flexural strength, flexural modulus, and im and (b), of a polyalkylene terephthalate wherein the
pact strength.
alkylene units contain 2 to 5 carbon atoms, and
Some polymeric materials, such as polyalkylene tere
(b) approximately 25 to approximately 95 percent by
phthalate and most wholly aromatic polyesters, exhibit weight, based upon the total weight of components (a)
an ordered structure in at least some regions of the 60 and (b), of a melt processable wholly aromatic polyester
polymer. This order can exist in one, two, or three which is capable of forming an anisotropic melt phase
dimensions. The inclusion in blends of polymeric mate apart from the blend.
rials exhibiting an ordered structure leads to an in creased tendency of the blends to separate into phases. This is due to the fact that the order found in certain 65
DETAILED DESCRIPTION OF THE INVENTION
regions of the polymer causes a fairly sharp boundary
The present invention provides a blend of polyalkyl
between the domains of the molecules of the component ene terephthalate and melt processable, wholly aro
polymers. Thus, blends including such polymers would matic polyester. As used herein, the term "blend" in-
4,489,190
6
susceptible to solution processing. As discussed previ
ously, they can be readily processed by common melt
processing techniques. Most suitable wholly aromatic polyesters are soluble in pentafluorophenol.
1 is -
The wholly aromatic polyesters which are suitable
for use in the blend of the present invention commonly
exhibit a weight average molecular weight of about
2,000 to 200,000, and preferably about 10,000 to 50,000,
e.g., about 20,000 to 25,000. Such molecular weight io may be determined by standard techniques not involv
11 is
, and
ing the solutioning of the polymer, e.g., by end group
determination via infrared spectroscopy on compres
sion molded films. Alternatively, light scattering tech niques in a pentafluorophenol solution may be em 15
III is *
ployed to determine the molecular weight.
The wholly aromatic polyesters additionally com
monly exhibit an inherent viscosity (i.e., I.V.) of at least
approximately 2.0 dl./g., e.g., approximately 2.0 to 8.0 20 The polyester comprises approximately 30 to 70 mole
dl./g., when dissolved in a concentration of 0.1 percent percent of moiety I. The polyester preferably comprises
by weight in pentafluorophenol at 60 C.
approximately 40 to 60 mole percent of moiety I, ap
The liquid crystalline, wholly aromatic polyesters
proximately 20 to 30 mole percent of moiety II, and approximately 20 to 30 mole percent of moiety III.
appear to have excellent electrical properties when used
The polyester disclosed in U.S. Application Ser. No.
as films or coatings in electrical applications. They have 25 10,392 is a melt processable wholly aromatic polyester
high temperature resistance and high dielectric which is capable of forming an anisotropic melt phase,
strength, i.e., they are capable of withstanding high apart from the blend, at a temperature no higher than
voltages without exhibiting substantial breakdown.
approximately 320 C. The polymer consists essentially
The above-described polyesters, in order to be useful j0 of the recurring moieties I, II, III, and IV wherein:
in the blend of the present invention, must exhibit opti
cal anisotropy in the melt phase. These polyesters
readily form liquid crystals in the melt phase and ac
cordingly exhibit a high tendency for the polymer I is
chains to orient in the shear direction. Such anisotropic 35
properties are manifested at a temperature at which the
wholly aromatic polyester readily undergoes melt pro
cessing to form shaped articles. The anisotropic proper
ties may be confirmed by conventional polarized light ^
techniques whereby crossed-polarizers are utilized.
More specifically, the anisotropic melt phase may con
veniently be confirmed by the use of a Leitz polarizing
microscope at a magnification of 40 X with the sample
on a Koffler hot stage and under a nitrogen atmosphere. 45
The melt phases of the wholly aromatic polyesters
which are suitable for use in the present invention are
optically anisotropic, i.e., they transmit light when ex
amined between crossed-polarizers. By contrast, the melt of a conventional polymer will not transmit appre 50
ciable light when placed between crossed-polarizers.
The wholly aromatic polyesters described above are
useful as molding resins and may also be used in the
formation of coatings, fibers, and films. They may be 55
molded by injection molding and can be processed by
any melt extrusion technique.
where R is methyl, chloro, bromo, or mixtures thereof,
Especially preferred wholly aromatic polyesters are and is substituted for a hydrogen atom present upon the
those which are disclosed in U.S. Pat. No. 4,184,996 and aromatic ring. The R group is preferably a methyl
U.S. Application Ser. No. 10,392, filed Feb. 8, 1979, 60 group.
now U.S. Pat. No. 4,238,599.
The polyester comprises approximately 20 to 60 mole percent of moiety I, approximately 5 to 18 mole percent
The polyester disclosed in U.S. Pat. No. 4,184,996 is of moiety II, approximately 5 to 35 mole percent of
a melt processable wholly aromatic polyester which is moiety III, and approximately 20 to 40 mole percent of
capable of forming an anisotropic melt phase at a tern- moiety IV. The polyester preferably comprises approxi
perature below approximately 325 C. apart from the mately 35 to 45 mole percent of moiety I, approximately
blend. The polyester consists essentially of the recur 10 to 15 mole percent of moiety II, approximately 15 to
ring moieties I, II, and III wherein:
25 mole percent of moiety III, and approximately 25 to
4,489,190
78
35 mole percent of moiety IV, with the proviso that the the components. In fact, within certain compositional
total molar concentration of moieties II and III is sub stantially identical to that of moiety IV.
ranges there is an increase in properties over even the individual component exhibiting the better mechanical
The wholly aromatic polyester described immedi properties. Moreover, the blend of the present inven
ately above is most preferred for inclusion in the blend 5 tion also provides an economic advantage. The combi
of the present invention. This wholly aromatic polyes nation of the relatively less expensive polyalkylene
ter commonly exhibits an inherent viscosity of at least 2.0 dl./g., e.g., 2.0 to 8.0 dl./g., when dissolved in a
terephthalate with the relatively more expensive wholly
aromatic polyester produces a blend which costs less
concentration of 0.3 weight/volume percent in penta- than the more expensive component but which exhibits
fluorophenol at 60 C.
10 no significant decrease in mechanical properties.
For the purposes of the present invention, the aro
The blend of the present invention is capable of un
matic rings which are included in the polymer back dergoing melt processing at a temperature within the
bones of the polymer components may include substitu range of approximately 260 C. to 350 C. Preferably,
tion of at least some of the hydrogen atoms present the blend is capable of undergoing melt processing at a
upon an aromatic ring. Such substituents include alkyl 15 temperature within the range of approximately 280 C.
groups of up to five carbon atoms; alkoxy groups hav to 300 C.
ing up to five carbon atoms; halogens; and additional
The blend of the present invention demonstrates an
aromatic rings, such as phenol and substituted phenol isotropy in the melt phase. This is due to the fact that
groups. Halogens which may be listed as possible sub the wholly aromatic polyester has been found to retain
stituents include fluorine, chlorine, and bromine. Al 20 its anisotropic characteristics in spite of the presence of
though bromine atoms tend to be released from organic the other component. Thus, the blend retains the excel
compounds at high temperatures, bromine is more sta lent processability characteristics of the liquid crystal
ble on aromatic rings than on aliphatic chains, and line polymer.
therefore is suitable for inclusion as a possible substitu
The blend of the present invention is useful as a mold
ent on the aromatic rings in the present blend.
25 ing resin, and especially for injection molding. The
The blend of the present invention comprises approx blend can also be used in the formation of fibers and
imately 5 to approximately 75 percent by weight of the films. Articles molded from the blend of the present
polyalkylene terephthalate component and approxi invention exhibit good mechanical properties, such as
mately 25 to approximately 95 percent by weight of the tensile strength, tensile modulus, flexural strength, flex
wholly aromatic polyester component. Preferably, the 30 ural modulus, notched Izod impact strength, the heat
blend comprises at least 30 percent by weight of the deflection temperature.
wholly aromatic polyester component. More prefera
Articles may also be molded from a molding com
bly, the blend comprises approximately 5 to approxi pound which includes, as one component, the blend of
mately 50 percent by weight of the polyalkylene tere the present invention. Such a molding compound incor
phthalate component and approximately 50 to approxi 35 porates into the blend of the present invention approxi
mately 95 by weight of the wholly aromatic polyester mately 1 to 50 percent, preferably approximately 10 to
component. The above weight percentages are based 30 percent, by weight, based upon the total weight of
upon the total weight of the wholly aromatic polyester the molding compound, of a solid filler and/or reinforc
component and the polyalkylene terephthalate compo ing agent. Representative fibers which may serve as
nent.
40 reinforcing media include glass fibers, asbestos, gra
In preparing the blend of the present invention, the phitic carbon fibers, amorphous carbon fibers, synthetic
individual components are commonly provided in the polymeric fibers, aluminum fibers, aluminum silicate
form of chips or pellets. Each of the components is fibers, oxide of aluminum fibers, titanium fibers, magne
weighed separately, and then the components are physi sium fibers, rock wool fibers, steel fibers, tungsten fi
cally mixed together in any appropriate apparatus, e.g., 45 bers, cotton, wool, and wood cellulose fibers, etc. Rep
a ball mill. The physical mixture is then dried at approx resentative filler materials include calcium silicate, sil
imately 100 C. overnight or for a period of time of ica, clays, talc, mica, polytetrafluoroethylene, graphite,
approximately 24 hours. The mixture is conveniently alumina trihydrate, sodium aluminum carbonate, bar
dried in a vacuum oven or in a circulating air oven, ium ferrite, etc.
although any suitable apparatus may be used. The pur 50 In order to form an article by injection molding from
pose of the drying step is to remove water from the the present blend, or from a molding compound made
physical mixture so as to prevent degradation of the from the present blend, the blend or molding compound
polymer blend. After the mixture of solid polymer parti is brought to the melt temperature of the blend, e.g.,
cles has been dried, the polymer blend can then be approximately 280 C. to 300 C., and is then injected
prepared. A convenient method of forming the polymer 55 into a mold cavity. The mold cavity is commonly main
blend is melt extrusion. The extrusion apparatus thor tained at a temperature less than approximately 100 C.,
oughly mixes the polymers in the melt and then ex e.g., approximately 90 C. to 100 C. The blend in its
trudes the blend in the form of a strand which, upon melt phase is injected into the mold cavity at a pressure
solidification, can be broken up into chips or pellets.
of approximately 10,000 p.s.i. The cycle time (i.e., the
As previously discussed, it is known in the art that 60 time between injections) for the present blend com
blends of two polymers tend to exhibit phase separation, monly is about 10 to 40 seconds.
with a concomitant reduction in properties, due to the
The properties of articles formed from blend compo
incompatibility of the polymers, i.e., the formation of sitions of the present invention can be improved by heat
domains. However, unexpected and surprising results treatment. The articles may be thermally treated in an
are achieved with the blend of the present invention. It 65 inert atmosphere (e.g., nitrogen, argon, helium) or alter
has been observed that there is no significant reduction natively a flowing oxygen-containing atmosphere (e.g.,
in mechanical properties of the blend when compared air). For instance, the article may be brought to a tem
to the weighted average of the mechanical properties of perature approximately 10 C. to 30 C. below the melt-
4,489,190
9 10
ing temperature of the blend, at which temperature the circulating air oven. The mixture of solid particles was
article remains a solid object. The heat treatment times then heated until a melt phase was formed, and the melt
commonly range from a few minutes to a number of was thoroughly mixed in a conventional melt extrusion
days, e.g., from 0.5 to 200 hours, or more. Preferably, apparatus. The resulting blend was extruded into the
the heat treatment is conducted for a time of 48 to 72 5 form of a strand, which, upon solidification, was broken
hours. The heat treatment improves the properties of up into solid particles of the polymer blend.
the article by increasing the molecular weight of the
In order to measure the mechanical properties of the
liquid crystalline polymer and increasing the degree of blend, shaped articles were molded from the polymer
crystallinity.
blends. The solid particles of the various compositions
Heat treatment has been observed to significantly 10 were heated to the melt temperature of the blend (ap
increase the heat deflection temperature of the blend. proximately 280 C.), and were subsequently injected
The heat deflection temperature is a measure of the into a mold cavity at an injection pressure of approxi
upper temperature at which articles formed from the mately 10,000 p.s.i. The mold cavity was held at a tem
blend can be effectively used. The blend of the present perature of approximately 21 C. The cycle time for the
invention can be characterized as a high performance 15 injection molding process was approximately 40 sec
blend in that it is capable of forming shaped articles onds.
having heat deflection temperatures greater than 200
The mechanical properties of the blend were mea
C. following heat treatment. Thus, the blend of the sured and are shown in Table I. The values of the prop
present invention is useful in applications involving erties of polyethylene terephthalate represent typical
relatively high temperatures.
20 values for PET; the properties of the PET actually used
It has been observed that the properties of articles in the present Example were not measured.
TABLE I
Blend Composition
Wholly Aroma tic Polyester Wholly Aroma tic Polyester: PET
90:10 70:30 PET
Tensile Strength
(p.s.i.) 32300
35000 31800
7380
Elongation (%) 4.31
4.15 3.29 3.32
Tensile Modulus (p.s.i. X 106)
1.76
1.86 1.78 0.34
Flexural Strength
(p.s.i.)
21300
Flexural Modulus (p.s.i. X 106)
1.28
Notched Izod Impact Strength (ft.-lbs.)
7.21
Heat Deflection Temp, at 264 p.s.i. cc.)
22400 20800
11500
1.39 1.26
0.36
5.79 2.66 0.58
194 167
--
formed from the blend of the present invention vary 35
with the processing conditions, such as mold tempera The tensile properties were determined in accordance
ture, injection pressure, cycle time, etc. However, it with standard test ASTM D638, Type V; the flexural
would be obvious to one of ordinary skill in the art to properties were determined in accordance with ASTM
experimentally determine those conditions which maxi D790; the notched Izod impact strength was deter
mize the properties of articles formed from the present 40 mined in accordance with ASTM D256; and the heat
blend.
deflection temperature was determined in accordance
The following examples are given as specific illustra with ASTM D648.
tions of the invention. It should be understood, how
The data for tensile and flexural properties listed in
ever, that the invention is not limited to the specific Table I clearly demonstrate the surprising and unex
details set forth in the Examples.
45 pected results provided by the blend compositions pre
EXAMPLE 1
pared in accordance with this Example. In general, the tensile and flexural properties are above those which
Blend compositions were prepared by the melt extru would be predicted from the weighted average of the
sion of polyethylene terephthalate and a wholly aro properties of the individual components. It can be seen
matic polyester. The polyethylene terephthalate exhib- 50 that articles formed from the compositions of the pres
ited an inherent viscosity of 0.91 when dissolved in a ent Example exhibit a tensile strength of no less than
concentration of 0.1 percent by weight in a chlorophe- approximately 24,000 p.s.i. and a flexural strength of no
nol at 60 C. The wholly aromatic polyester comprised less than approximately 20,000 p.s.i. Furthermore, no
40 mole percent of 4-oxybenzoyl units, 15 mole percent reduction in properties, as compared to the properties
of l,2-ethylenedioxy-4,4'-dibenzoyl units, 15 mole per- 55 of polyethylene terephthalate, is observed, as would be
cent of terephthaloyl units, and 30 mole percent of expected.
methyl substituted 1,4-dioxyphenylene units. The wholly aromatic polyester exhibited an inherent viscos
EXAMPLE 2
ity (I.V.) of 2.47 dl./g. when dissolved in a concentra
Blend compositions were prepared in the manner
tion of 0.3 weight/volume percent in pentafluorophenol 60 described in Example 1 from polyethylene terephthal
at 60' C. The ratios of wholly aromatic polyester:- ate and a second batch of the wholly aromatic polyester
polyethylene terephthalate in the blend compositions described therein. The wholly aromatic polyester was
were 90:10 and 70:30.
comprised of 90 percent by weight of a sample having
The component polymers, in the form of solid parti an inherent viscosity of 3.00 dl./g. and 10 percent by
cles, such as chips or pellets, were weighed separately 65 weight of a sample having an inherent viscosity of 2.23
and were subsequently physically mixed together in a dl./g. The ratios of wholly aromatic polyester-
ball mill. The mixture of solid particles was dried at polyethylene terephthalate of the blend compositions
approximately 100 C. overnight in a vacuum oven or were 50:50 and 30:70.
4,489,190
11 12
Articles were molded from the polymer blend com terephthalate, as would be expected. On the contrary,
positions in the manner described in Example 1. The the addition of polyethylene terephthalate to the wholly
mechanical properties of the articles were measured aromatic polyester provides a blend which is less expen
according to the tests listed in Example 1. The results of sive than the wholly aromatic polyester alone, yet
the tests are given in Table II. The mechanical proper which retains good mechanical properties.
ties of articles produced from the wholly aromatic poly
It is to be understood that the foregoing detailed
ester actually used in this Example were not measured; description is given merely by way of illustration and
the values listed represent typical values obtained from that many variations may be made therein without de
a sample prepared in substantially the same manner as parting from the spirit of the invention.
that of the present Example.
I claim:
TABLE II
Blend Composition
Wholly Aroma tic Polyester Wholly Aroma tic Polyester: PET
50:50 30:70 PET
Tensile Strength
(p.s.i.) 32300
24600 16600 7380
Elongation (%) 4.31
1.83 2.04 3.32
Tensile Modulus (p.s.i. X 106)
1.76
1.88 1.07 0.34
Flexural Strength
(p-S-i.)
21300
Flexural Modulus (p.s.i. X 106)
1.28
Notched Izod Impact Strength (ft-lbs.)
7.21
Heat Deflection Temp, at 264
cop.s.i.
20500 17000 11500
1.44 0.93 0.36
0.38 0.33 0.58
75 70
"
The data for tensile and flexural properties listed in
1. A polymer blend which is capable of exhibiting an
table II again indicate no significant reduction in prop- 25 anisotropic melt phase and the ability to form shaped
erties of the blend compositions of the present Example articles having satisfactory mechanical properties com
as compared to the weighted average of the properties prising:
of the individual components. Moreover, the data indi
(a) approximately 5 to approximately 50 percent by
cate that blend compositions of at least 50 percent
weight, based upon the total weight of components
wholly aromatic polyester exhibit a tensile strength of 30
(a) and (b), of a polyalkylene terephthalate wherein
no less than approximately 24,000 p.s.i. and a flexural
the alkylene units contain B 2 to 5 carbon atoms,
strength of no less than approximately 20,000 p.s.i.
and
EXAMPLE 3
(b) approximately 50 to approximately 95 percent by weight, based upon the total weight of components
Blend compositions were prepared in the manner 35
(a) and (b), of a melt processable wholly aromatic
described in Example 1 from polyethylene terephthal
polyester which is capable of forming an aniso
ate and a wholly aromatic polyester comprising 60 mole
tropic melt phase apart from said blend.
percent 4-oxybenzoyl units, 20 mole percent of 2,6-diox-
2. A polymer blend according to claim 1 which is
ynaphthalene units, and 20 mole percent of terephthal- capable of undergoing melt processing at a temperature
oyl units. The wholly aromatic polyester exhibited an 40 within the range of approximately 260 C. to 350 C.
I.V. of 2.9 dl./g. when dissolved in a concentration of
3. A polymer blend according to claim 1 which is
0.1 percent by weight in pentafluorophenol at 60 C. capable of undergoing melt processing at a temperature
The ratios of wholly aromatic polyesteripolyethylene within the range of approximately 280 C. to 300 C.
terephthalate of the blend compositions were 90:10,
4. A polymer blend according to claim 1 wherein the
80:20, 70:30, 50:50, and 30:70.
45 alkylene units of said polyalkylene terephthalate con
Articles were molded from the blend compositions of tain 2 to 4 carbon atoms.
the present Example in the manner described in Exam
5. A polymer blend according to claim 1 wherein said
ple 1. The mechanical properties of these articles were polyalkylene terephthalate is polyethylene terephthal
measured according to the tests listed in Example 1. ate.
The results of these tests are listed in Table III.
50
TABLE III
Blend Composition
Wholly Aroma tic Polyester Wholly Aroma tic Polyester: PET
90:10 80:20 70:30 50:50 30:70 PET
Yield value
Tensile Strength
(p.s.i.) 23100
13000 10200 8540 7201
--
7380
Elongation (%) 1.78
1.27 1.17 1.44 2.63
--
3.32
Tensile Modulus (p.s.i. X 106)
2.18
1.45 1.19 0.82 0.44
--
0.34
Flexural Strength
(p.s.i.)
21700
Flexural Modulus (p.s.i. X 106)
1.69
Notched Izod Impact Strength (ft.-lbs.)
1.95
Heat Deflection Temp, at 264
cp.so.i.
15300 13700 12000 11600 12200* 11500
1.36 1.25 1.05 0.46 0.41 0.36
0.57 0.71 0.51 0.26 0.34 0.58
250 241 110
65 64 62
As the data indicate, there is no significant reduction in properties, as compared to those of polyethylene
4,489,190
13
14
6. A polymer blend according to claim 1 wherein said wholly aromatic polyester apart from said blend is capa
-continued
ble of forming an anisotropic melt phase at a tempera
ture below approximately 350 C. 7. A polymer blend according to claim 1 wherein said
5
wholly aromatic polyester apart from said blend exhib
its an inherent viscosity of at least 2.0 dl./g. when dis
solved in a concentration of 0.1 percent by weight in
pentafluorophenol at 60 C.
10
8. A polymer blend according to claim 1 wherein said
melt processable wholly aromatic polyester is capable
of forming an anisotropic melt phase at a temperature wherein said polyester comprises approximately 30 to
no higher than approximately 320 C. apart from said blend and consists essentially of the recurring moieties
15
70 mole percent of moiety I. 11. A molding compound comprising
the
polymer
I, II, III, and IV wherein:
blend of claim 1 which incorporates approximately 1 to 50 percent by weight, based upon the total weight of
said molding compound, of a material selected from the
20 group consisting of solid filler, reinforcing agent, and the mixtures thereof. 12. A molding compound according to claim 11
which incorporates approximately 10 to approximately
30 percent by weight, based upon the total weight of
25 said molding compound, of a material selected from the group consisting of solid filler, reinforcing agent, and
mixtures thereof.
13. A molded article comprising the blend of claim 1.
14. A fiber which has been melt spun from the blend
30 of claim 1. 15. A film which has been melt extruded from the
blend of claim 1.
16. A polymer blend according to claim 1 which is
capable of being satisfactorily molded while employing
35 a mold temperature less than approximately 100 C. 17. A polymer blend which is capable of exhibiting an
anisotropic melt phase and the ability to form shaped
articles having improved mechanical properties com
prising:
40 (a) approximately 5 to approximately 50 percent by weight, based upon the total weight of components
(a) and (b), of polyethylene terephthalate, and
(b) approximately 50 to approximately 95 percent by
where R is methyl, chloro, bromo, or mixtures thereof, and is substituted for a hydrogen atom 45 present upon the aromatic ring,
wherein said melt processable wholly aromatic polyes
ter consists of approximately 20 to 60 mole percent of moiety I, approximately 5 to 18 mole percent of moiety 50 II, approximately 5 to 35 mole percent of moiety III,
weight, based upon the total weight of components (a) and (b), of a melt processable wholly aromatic polyester which is capable of forming an aniso tropic melt phase at a temperature no higher than approximately 320 C. apart from said blend and consists essentially of the recurring moieties I, II, III, and IV wherein:
and approximately 20 to 40 mole percent of moiety IV.
9. A polymer blend according to claim 8 wherein said
R group of moiety IV is a methyl group.
10. A polymer blend according to claim 1 wherein 55
said melt processable wholly aromatic polyester is capa
ble of forming an anisotropic melt phase at a tempera
ture below approximately 325 C. apart from said blend
and consists essentially of the recurring moieties I, II,
and III wherein:
60
65
15
-continued
4,489,190
5
16
wherein said polyester comprises approximately 20 to 10
60 mole percent of moiety I, approximately 5 to 18 mole
percent of moiety II, approximately 5 to 35 mole per
cent of moiety III, and approximately 20 to 40 mole
percent of moiety IV. 18. A polymer blend according to claim 17 wherein 15
said melt processable wholly aromatic polyester con
sists essentially of approximately 35 to 45 mole percent
of moiety I, approximately 10 to 15 mole percent of
moiety II, approximately 15 to 25 mole percent of moi ety III, and approximately 25 to 35 mole percent of 20
moiety IV, with the proviso that the total molar con
centration of moieties II and III is substantially identical
to that of moiety IV.
19. A polymer blend according to claim 18 which is capable of undergoing melt processing at a temperature 25
within the range of approximately 280* C. to 300 C. 20. A polymer blend according to claim 18 wherein
wherein said polyester comprises approximately 35 to 45 mole percent of moiety I, approximately 10 to 15
said wholly aromatic polyester exhibits an inherent mole percent of moiety II, approximately 15 to 25 mole
viscosity of at least 2.0 dl./g. when dissolved in a con centration of 0.3 weight/volume percent in penta-
30
percent of moiety III, and approximately 25 to 35 mole percent of moiety IV, with the proviso that the total
fluorophenol at 60 C.
molar concentration of moieties II and III is substan
21. A molding compound comprising the polymer tially identical to that of moiety IV.
blend of claim 18 which incorporates approximately 1
27. A polymer blend according to claim 26 which is
to 50 percent by weight, based upon the total weight of said molding compound, of a material selected from the 35
capable of undergoing melt processing at a temperature within the range of approximately 280 C. to 300 C.
group consisting of solid filler, reinforcing agent, and
28. A polymer blend according to claim 26 wherein
mixtures thereof.
said wholly aromatic polyester apart from said blend
22. A molding compound according to claim 21 exhibits an inherent viscosity of approximately 2.0 to 8.0
which incorporates approximately 10 to 30 percent by weight, based upon the total weight of said molding
40
dl./g. when dissolved in a concentration of 0.3 weight/volume percent in pentafluorophenol at 60 C.
compound, of a material selected from the group con
29. A molding compound comprising the polymer
sisting of solid filler, reinforcing agent, and mixtures blend of claim 26 which incorporates approximately 1
thereof.
to 50 percent by weight, based upon the total weight of
23. A molded article comprising the polymer blend of 45 said molding compound, of a material selected from the
claim 17.
group consisting of solid filler, reinforcing agent, and
24. A fiber which has been melt spun from the poly mixtures thereof.
mer blend of claim 17.
30. A molding compound according to claim 29
25. A film which has been melt extruded from the which incorporates approximately 10 to approximately
polymer blend of claim 17.
50 30 percent by weight, based upon the total weight of
26. A polymer blend which is capable of exhibiting an said molding compound, of a material selected from the
anisotropic melt phase and the ability to form shaped articles having improved' mechanical properties com prising:
group consisting of solid filler, reinforcing agent, and mixtures thereof.
31. A molded article comprising the polymer blend of
(a) approximately 5 to approximately 50 percent by 55 claim 26.
weight, based upon the total weight of components
32. A molded article according to claim 31 which
(a) and (b), of polyethylene terephthalate, and
exhibits a tensile strength of no less than approximately
(b) approximately 50 to approximately 95 percent by 24,000 p.s.i. and a flexural strength of no less than ap
weight, based upon the total weight of components proximately 20,000 p.s.i.
(a) and (b), of a melt processable wholly aromatic 60 33. A fiber which has been melt spun from the poly polyester which is capable of forming an aniso mer blend of claim 26.
tropic melt phase at a temperature no higher than
34. A film which has been melt extruded from the
approximately 320 C. and consists essentially of polymer blend of claim 26.
the recurring moieties I, II, III, and IV wherein:
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65