Improved compositions comprise isomorphic polymer blends of at least two linear alternating polymers of carbon monoxide and one or more ethylenically unsaturated hydrocarbons. A preferred composition is the combination of a linear alternating polyketone copolymer of carbon monoxide and ethylene with a linear alternating polyketone terpolymer of carbon monoxide, ethylene, and a second ethylenically unsaturated hydrocarbon of at least 3 carbon atoms, particularly propylene.

FIELD OF THE INVENTION 
This invention relates to polyketone polymer blends, and, more 
particularly, to miscible blends of a polyketone copolymer with a 
polyketone terpolymer that exhibit isomorphism in the molded state. 
BACKGROUND OF THE INVENTION 
Polyketone polymers are semi-crystalline polymers which possess an 
attractive set of properties for a variety of applications. The utility of 
these polymers can be further broadened by selectively blending polyketone 
polymers with other materials which have complimentary property sets. 
The mixing together of two or more polymers has attracted interest as a 
means of arriving at new property combinations without the need to 
synthesize novel structures. The most common polymer blends are 
immiscible. In most cases, when two polymers are mixed, the components 
tend to segregate into separate phases, forming a non-adhering, 
heterogeneous mixture that exhibits inferior overall properties. 
However, on rare occasions, polymer pairs will form miscible blends. The 
term miscible describes a mixture of two or more polymers that form a 
single-phase solution (solid or liquid) within the amorphous phase on a 
molecular scale. When one or both of the polymer blend components is 
capable of forming both a crystalline and an amorphous phase (i.e. a 
semicrystalline polymer), then the term miscible refers only to the 
amorphous phase in which the separate components are capable of mixing on 
the molecular level. Miscibility is indicated by a single glass transition 
temperature for a blend of two or more components. 
Blends which exhibit isomorphism are even more rare than miscible blends. 
The term isomorphic will be used herein to describe a mixture of two or 
more polymers that co-crystallize, exhibiting only one crystallization 
point temperature (and also, only one melting point temperature). 
Isomorphic polymer pairs form both a miscible blend in the melt and 
cocrystallize when converted to the solid state. 
Examples of isomorphic polymer pairs include aromatic polyetherketone 
polymer pairs and binary blends of copolymers of vinylidene fluoride and 
trifluoroethylene. U.S. Pat. No. 4,609,714 (Harris et al.), incorporated 
herein by reference, discloses isomorphic poly(aryl ether) resin pairs and 
also provides a description of isomorphism. Isomorphic polymer systems 
require the different types of monomer units to have approximately the 
same shape and volume (to allow co-crystallization), and to have a 
chemical attraction that promotes miscibility in the melt phase. 
It is an object of this invention to provide an isomorphic blend of two or 
more polyketone polymers. 
SUMMARY OF THE INVENTION 
The invention provides an isomorphic blend comprising at least two 
separately made linear alternating polyketone polymers, each having a 
different crystallization point and melting point temperature prior to 
their combination, formed into an intricate moldable mixture. The blends 
exhibit a single crystallization temperature and a single melting point 
temperature, indicative of the rare quality of isomorphism in the molded 
state. The blends posses a broader range of use temperatures than the 
unblended polymers. A preferred blend is the combination of a linear 
alternating polyketone copolymer of carbon monoxide and ethylene with a 
linear alternating polyketone terpolymer of carbon monoxide, ethylene, and 
a second ethylenically unsaturated hydrocarbon of at least 3 carbon atoms, 
particularly propylene. The invention also provides a method of increasing 
the crystallization temperature of a polyketone terpolymer by 
incorporating therein a polyketone copolymer. Concurrently, the invention 
also provides a method of increasing the melting point of a polyketone 
terpolymer, thereby increasing its use temperature, by incorporating 
therein a polyketone copolymer. Articles manufactured from the isomorphic 
blends are also within the scope of the invention. 
DETAILED DESCRIPTION OF THE INVENTION 
It has been found in accordance with this invention that an isomorphic 
polyketone polymer blend can be obtained by blending together a polyketone 
copolymer with a polyketone terpolymer, particularly a copolymer of 
ethylene and carbon monoxide with a terpolymer of ethylene, propylene, and 
carbon monoxide. As used herein, the term copolymer shall mean a polymer 
of two monomer units (such as ethylene and carbon monoxide), and the term 
terpolymer shall mean a polymer of three monomer units (such as ethylene, 
propylene, and carbon monoxide). 
A criterion useful for identifying isomorphism, as used herein, is the 
existence of a single crystallization temperature for a given polymer 
blend, rather than two separate crystallization temperatures for the two 
blend components. This parameter is relatively easy to measure using 
differential scanning calorimetry (DSC) techniques. When the crystalline 
structure is very uniform, crystallization will occur over a very narrow 
temperature range, and a sharp crystallization peak will be observed in 
the DSC data. As the relative proportion of components changes, a smooth 
transition between the crystallization temperatures for each of the pure 
blend components and the crystallization temperatures for the various 
blends will be observed. The existence of a single melting point 
temperature for a given polymer blend may be similarly used to indicate an 
isomorphic polymer blend. 
Isomorphic blends possess a broader range of use temperatures than the 
unblended polymers. Isomorphic polymer blends can be used to make molded 
parts at temperatures above the melting point of the polymer with the 
lower melting point, yet below the melting point of the polymer with the 
higher melting point. Since the blend is isomorphic, it exhibits only one 
melting point for the blend, rather than two separate melting points (one 
for each component of the blend). The resulting elevation in the melting 
point for the lower melting point polymer allows its use in parts 
requiring a higher use temperature. Concurrently with the increase in 
melting point, the crystallization temperature of the polymer with a lower 
crystallization point is elevated by the combination with a polymer with a 
higher crystallization temperature. The isomorphic blend crystallizes at a 
higher temperature, allowing shorter cycle times and reduced energy costs 
for the manufacture of molded parts. 
For the isomorphic polyketone polymer blends of the invention, it has been 
found that the addition of from about 20 wt % to about 50 wt %, and 
preferably about 25 to about 35 wt %, of a polyketone copolymer to a 
polyketone terpolymer increases both the crystallization point and the 
melting point temperatures of a polyketone terpolymer up to about the 
crystallization point and melting point temperatures of the polyketone 
copolymer. Preferably, the polyketone copolymer is a polymer of carbon 
monoxide and ethylene, and the polyketone terpolymer is preferably a 
polymer of carbon monoxide, ethylene, and propylene. 
The polyketone polymers of the blends of the invention are of a linear 
alternating structure and contain substantially one molecule of carbon 
monoxide for each molecule of unsaturated hydrocarbon. Suitable 
ethylenically unsaturated hydrocarbons for use as monomers in the 
polyketone polymers have up to 20 carbon atoms inclusive, preferably up to 
10 carbon atoms, and are aliphatic such as ethylene and other 
.alpha.-olefins including propylene, 1-butene, isobutylene, 1-hexene, 
1-octene and 1-dodecene. The preferred polyketone polymer blend components 
are copolymers of carbon monoxide and ethylene, and terpolymers of carbon 
monoxide, ethylene and a second ethylenically unsaturated hydrocarbon of 
at least 3 carbon atoms, particularly propylene. 
The polyketone terpolymers include within the terpolymer at least about 2 
units incorporating a monomer of ethylene for each unit incorporating a 
monomer of the second ethylenically unsaturated hydrocarbon. Preferably, 
there will be from about 10 units to about 100 units incorporating a 
monomer of ethylene for each unit incorporating a monomer of the second 
hydrocarbon. The polymer chain of the polyketone terpolymers is therefore 
represented by the repeating formula 
EQU --CO(CH.sub.2 --CH.sub.2)].sub.x [CO(G)].sub.y 
wherein G is the monomer of ethylenically unsaturated hydrocarbon of at 
least 3 carbon atoms polymerized through the ethylenic unsaturation and 
the ratio of y:x is no more than about 0.5. The --CO--CH.sub.2 CH.sub.2) 
units and the --CO(G) units are found randomly throughout the polymer 
chain, and preferred ratios of y:x are from about 0.01 to about 0.1. 
The copolymers of carbon monoxide and ethylene that are employed in the 
blends of the invention are represented by the above formula wherein y is 
zero. The end groups or "caps" of the polymer chain will depend upon what 
materials were present during the production of the polymer and whether or 
how the polymer was purified. The precise nature of the end groups does 
not appear to influence the properties of the polymer to any considerable 
extent so that the polymers are fairly represented by the formula for the 
polymer chain as depicted above. 
Of particular interest are the polyketone polymers of number average 
molecular weight from about 1000 to about 200,000, particularly those of 
number average molecular weight from about 20,000 to about 90,000 as 
determined by gel permeation chromatography. The physical properties of 
the polymer will depend in part upon the molecular weight, whether the 
polymer is a copolymer or a terpolymer and, in the case of terpolymers, 
the nature of and the proportion of the second hydrocarbon present. 
Typical melting points for the polymers are from about 175.degree. C. to 
about 300.degree. C., more typically from about 210.degree. C. to about 
270.degree. C. The polymers have a limiting viscosity number (LVN), 
measured in m-cresol at 60.degree. C. in a standard capillary viscosity 
measuring device, from about 0.5 dl/g to about 10 dl/g, more frequently 
from about 0.8 dl/g to about 4 dl/g. 
U.S. Pat. No. 4,880,903 (Van Broekhoven et al.) discloses a linear 
alternating polyketone terpolymer of carbon monoxide, ethylene, and other 
olefinically unsaturated hydrocarbons, such as propylene. Processes for 
production of the polyketone polymers typically involve the use of a 
catalyst composition formed from a compound of a Group VIII metal selected 
from palladium, cobalt or nickel, the anion of a strong non-hydrohalogenic 
acid and a bidentate ligand of phosphorus, arsenic or antimony. U.S. Pat. 
No. 4,843,144 (Van Broekhoven et al.) discloses a process for preparing 
polymers of carbon monoxide and at least one ethylenically unsaturated 
hydrocarbon using a catalyst comprising a compound of palladium, the anion 
of a non-hydrohalogenic acid having a pKa of below about 6 and a bidentate 
ligand of phosphorus. 
The carbon monoxide and hydrocarbon monomer(s) are contacted under 
polymerization conditions in the presence of a catalyst composition formed 
from a compound of palladium, the anion of a non-hydrohalogenic acid 
having a pKa (measured in water at 18.degree. C.) of below about 6 and a 
bidentate ligand of phosphorus. The scope of the polymerization is 
extensive but, without wishing to be limited, a preferred palladium 
compound is a palladium carboxylate, particularly palladium acetate, a 
preferred anion is the anion of trifluoroacetic acid or p-toluenesulfonic 
acid and a preferred bidentate ligand of phosphorus is 
1,3-bis[di(2-methoxyphenyl)phosphino]propane or 
1,3-bis(diphenylphosphino)propane. 
The polymerization to produce the polyketone polymer is conducted in an 
inert reaction diluent, preferably an alkanolic diluent, and methanol is 
preferred. The reactants, catalyst composition and reaction diluent are 
contacted by conventional methods such as shaking, stirring or refluxing 
in a suitable reaction vessel. Typical polymerization conditions include a 
reaction temperature from about 20.degree. C. to about 150.degree. C., 
preferably from about 50.degree. C. to about 135.degree. C. The reaction 
pressure is suitably from about 1 atmosphere to about 200 atmospheres but 
pressures from about 10 atmospheres to about 100 atmospheres are 
preferred. Subsequent to polymerization, the reaction is terminated as by 
cooling the reactor and contents and releasing the pressure. The 
polyketone polymer is typically obtained as a product substantially 
insoluble in the reaction diluent and the product is recovered by 
conventional methods such as filtration or decantation. The polyketone 
polymer is used as recovered or the polymer is purified as by contact with 
a solvent or extraction agent which is selective for catalyst residues. 
The blends of the invention may also include additives such as antioxidants 
and stabilizers, dyes, fillers or reinforcing agents, fire resistant 
materials, mold release agents, colorants and other materials designed to 
improve the processability of the polymers or the properties of the 
resulting blend. Such additives are added prior to, together with or 
subsequent to the blending of the polyketone and the copolymer. 
The method of producing the blends of the invention is not material so long 
as an isomorphic blend is produced without undue degradation of the blend 
or its components. In one modification the polymer components of the blend 
are extruded in a corotating twin screw extruder to produce the blend. In 
an alternate modification, the polymer components are blended in a mixing 
device which exhibits high shear. The blends are processed by methods such 
as extrusion and injection molding into sheets, films, plates and shaped 
articles. Illustrative applications are the production of articles useful 
in both rigid and flexible packaging, both internal and external parts for 
the automotive industry, and structural parts for the construction 
industry.

The invention is further illustrated by the following Examples which should 
not be regarded as limiting. 
EXAMPLE 1 
A linear alternating terpolymer of carbon monoxide, ethylene, and propylene 
(89/068) was produced in the presence of a catalyst composition formed 
from palladium acetate, trifluoroacetic acid and 
1,3-bis[di(2-methoxyphenyl)phosphino]propane. The polyketone polymer had a 
melting point of about 220.degree. C. and an LVN of about 1.8 dl/g when 
measured in m-cresol at 60.degree. C. The polyketone polymer also 
contained 0.5% Irganox 1076 and 0.5% Nucrel, both conventional additives. 
EXAMPLE 2 
A linear alternating copolymer of carbon monoxide and ethylene (89/089) was 
produced in the presence of a catalyst composition formed from palladium 
acetate, trifluoroacetic acid and 
1,3-bis[di(2-methoxyphenyl)phosphino]propane. The polyketone polymer had a 
melting point of about 250.degree. C. and an LVN of about 1.6 dl/g when 
measured in m-cresol at 60.degree. C. The polyketone polymer also 
contained 0.5% Irganox 1076 and 0.5% Nucrel, both conventional additives. 
EXAMPLE 3 
Blends of the polyketone terpolymer of Example 1 and the polyketone 
copolymer of Example 2 were prepared by compounding the polymers on a 30 
mm corotating twin screw extruder at a melt temperature of 265.degree. C. 
The extruded nibs were evaluated for melting and crystallization 
temperatures in a Perkin Elmer differential scanning calorimeter (DSC) 
operated at a 10.degree. C./minute heating and cooling rate. Samples were 
also injection molded into family test specimens and evaluated for tensile 
strength, flexural modulus, notched Izod impact, low temperature Gardner 
impact, and heat deflection temperature (at 264 psi). All samples were 
tested dry as molded. 
The isomorphism of the blends is demonstrated by the melting and 
crystallization temperatures for the polymer blends, as shown in Tables 1 
and 2. The peak temperatures shown are those that would commonly be 
reported as the melting point or crystallization point temperatures. 
TABLE 1 
______________________________________ 
Terpolymer 
Copolymer Melting Temperature (.degree.C.) 
(wt %) (wt %) Onset Peak Complete 
______________________________________ 
100 0 157 216 230 
90 10 146 219 241 
70 30 161 246 252 
50 50 171 249 255 
30 70 199 249 256 
10 90 206 250 255 
0 100 205 249 256 
______________________________________ 
TABLE 2 
______________________________________ 
Terpolymer 
Copolymer Crystallization Temperature (.degree.C.) 
(wt %) (wt %) Onset Peak Complete 
______________________________________ 
100 0 141 175 192 
90 10 131 182 197 
70 30 131 190 207 
50 50 140 195 211 
30 70 153 199 211 
10 90 114 201 212 
0 100 134 197 210 
______________________________________ 
The peak melting temperatures of all blends containing 30 wt % or more of 
the copolymer exceeded values that would be predicted from the linear rule 
of mixtures or that predicted by equilibrium thermodynamics. The blends 
containing from 30 wt % to 90 wt % copolymer all exhibited melting 
temperatures similar to that of the 100 wt % copolymer. 
The peak crystallization temperatures of all of the blends exceeded values 
that would be predicted from a linear rule of mixtures or from equilibrium 
thermodyamics. Again, the blends containing from 30 wt % to 90 wt % 
copolymer all exhibited crystallization temperatures similar to that of 
the 100 wt % copolymer. 
The results of mechanical and thermal property tests are shown in Table 3. 
The results for these parameters generally follow a rule of mixtures for 
the two blend components. Notched Izod impact for the copolymer was 
similar to that for the terpolymer, yet the 30/70, 50/50, and 70/30 blends 
exhibited slightly higher notched Izod impact resistance than such values 
for the neat copolymer or terpolymer. Gardner impacts varied but were good 
for all samples. Heat deflection temperature followed an approximate rule 
of mixture behavior. 
The results in Table 3 indicate that the copolymer exhibits a superior 
balance of properties, including higher strength and stiffness. There may 
be applications where better flexibility is required, and this could be 
achieved by blends of the copolymer with the terpolymer. 
TABLE 3 
__________________________________________________________________________ 
Low Temperature 
Room Temperature 
(-30.degree. C.) 
Terpolymer 
Copolymer 
Tensile 
Flexural 
Notched Gardner Heat Deflection 
(wt %) (wt %) 
Strength (psi) 
Modulus (psi) 
Izod (ft-lbs/in) 
Impact (in-lb) 
Temperature 
__________________________________________________________________________ 
(.degree.C.) 
100 0 8195 232,000 
4.7 96 83 
90 10 8438 246,000 
4.4 62 85 
70 30 8791 253,000 
5.1 95 -- 
50 50 9459 275,000 
5.3 73 105 
30 70 9847 281,000 
5.3 214 102 
10 90 10,550 313,000 
4.8 195 137 
0 100 11,073 344,000 
4.7 228 170 
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