Polyketone compositions can be stabilized by the addition of a suitable stabilizing amount of a blend of a hindered phenol compound, such as a thioester-containing hindered phenol and an epoxy compound (such as an epoxy cycloaliphatic carboxylate).

BACKGROUND OF THE INVENTION 
Copolymers of carbon monoxide and an olefin, commonly termed a 
"polyketone", are a well-recognized class of copolymer synthesized through 
copolymerization of carbon monoxide with one or more olefins in the 
presence of a suitable catalyst. 
Certain disclosures exist in the patent literature in regard to the 
stabilization of polyketone materials including: U.S. Pat. Nos. 3,929,727 
(use of 2,2'-dihydroxy-4-methoxybenzophenone); 3,948,832 (use of one or 
more epoxy group-containing compounds alone); 4,024,104 (use of 
substituted 2(2'-hydroxyphenyl)-benzotriazoles); 4,761,448 (use of an 
aluminum trialkoxide or hydrolysis product thereof); 4,795,774 (use of 
certain aromatic amines of up to two aromatic rings and at least one amino 
group); 4,808,678 (use of a polymeric, linear hydroxyalkyl ether of 
bis(hydroxyphenyl)alkane); 4,857,570 (use of a succinic anhydride or 
hydrolysis product thereof); 4,950,703 (use of aluminum phenoxide); 
4,954,548 (use of an aromatic diamine and a particular type of carbon 
black); 4,954,552 (use of barium or titanium acetylacetonate); 4,954,555 
(use of aluminum stearate); 4,960,807 (use of zinc oxide, zinc sulfide and 
a trialkylphosphite); and 4,960,808 (use of certain phenolic compounds). 
U.S. Patent Document No. H732 (use of an oligomer derived from 
epihalohydrin and a hydroxyphenylalkane); European Patent Publication Nos. 
288,124 (use of diarylamines, hydroxybenzophenones, and benzotriazoles or 
benzotriazines); 326,223 (use of a sterically hindered phenolic (blend) 
compound of a particular type); and 326,224 (use of certain acid amides or 
aluminum compounds). 
SUMMARY OF THE INVENTION 
The present invention resides in the use of a blend of a hindered phenol 
compound and an epoxy compound as the stabilizing agents for the 
aforementioned class of polyketone. 
DETAILED DESCRIPTION OF THE PRESENT INVENTION 
The disclosures of the various aforementioned U.S. patents is incorporated 
herein by reference in regard to their teaching as to how the polyketone 
composition which is to be stabilized can be formed. Generally speaking, 
such polymers will have a molecular weight of anywhere from about 1,000 to 
about 1,000,000, preferably about 50,000 to about 250,000. They can be 
formed by polymerizing the appropriate monomers (i.e. carbon monoxide and 
the selected olefin or olefins) in the presence of a catalytic amount of a 
catalyst formed from a compound of a Group VIII metal, an anion of a 
non-hydrohalogenic acid, and a bidentate ligand of phosphorus, arsenic or 
antimony. 
In accordance with the present invention, the above-referenced polymers 
have intimately mixed therewith a suitable stabilizing quantity of a blend 
of a hindered phenol compound and an epoxy compound. 
The hindered phenol compounds which are useful herein comprise compounds of 
the general formula 
EQU HOAr--L--ArOH 
where Ar is a phenyl group containing one or more branched chain alkyl 
substituents shielding the hydroxy substituent thereon and where L is a 
suitable linking group between the substituents ArOH. For example, the 
esters of hindered hydroxybenzoic and hydroxyphenylalkanoic acids 
described in U.S. Pat. Nos. 3,285,855 and 3,441,575 form one class of 
esters useful as hindered phenol compounds herein. A particularly 
preferred compound of this class is a thioester-containing hindered phenol 
which is sold under the trademark IRGANOX 1035 and is thiodiethylene 
bis-(3,5-di-tert-butyl-4-hydroxy)hydrocinnamate. 
The epoxy compound stabilizer component which can be used with the 
aforementioned aromatic amine compound include the type of epoxy compounds 
described in U.S. Pat. No. 3,948,832 at Col. 2, lines 20 to 47 inclusive, 
which is incorporated herein by reference. Representative compounds are 
organic compounds (e.g., aliphatic, including cycloaliphatic, or aromatic 
which contain one or, more epoxy groups. One particularly preferred epoxy 
is an epoxy cycloaliphatic carboxylate, such as 
(3',4'-epoxycyclohexylmethyl)3,4-epoxycyclohexanecarboxylate. 
It is preferred that both the hindered phenol and epoxy compounds chosen 
have a relatively low vapor pressure so that they will be retained in the 
polyketone during high temperature processing or use of such compositions. 
In general, the amounts of the stabilizer blend that are used in accordance 
with the present invention can range anywhere from about 1%, by weight, up 
to about 25%, by weight of the polyketone. Preferable amounts range from 
about 5% to about 15%, by weight, of the polyketone. Generally, it is 
advisable to choose an amount of stabilizer at the lower portions of the 
above given ranges in order to avoid adversely affecting the mechanical 
properties of the resulting polyketone. In general, the weight ratio of 
hindered phenol compound to epoxy compound in, the stabilizer blend can 
range anywhere from about 1:5 to about 5:1. 
The stabilizer blend of this invention is preferably added to the 
polyketone by blending when the polyketone is in the form of a powder or 
dissolved in a solvent. The method of incorporation is not believed to be 
critical although it is preferred that a homogeneous mixture of polyketone 
and stabilizer blend be achieved. 
Other additives, such as fillers, extenders, plasticizers, coloring agents, 
other polymeric materials, etc., can be added to the polyketone being 
stabilized. 
The resulting stabilized polyketone compositions exhibit improved thermal 
stability and can be processed for extended periods of time at elevated 
temperatures with an enhanced degree of stability. Typical methods of 
processing include injection molding, pressure forming, thermoforming and 
sheet extrusion. The materials can be used in applications where such 
polyketones are likely to encounter elevated temperatures including the 
thermoforming of food or drink containers, the production of shaped 
automotive parts by injection molding, or the production of wire and cable 
coatings by extrusion. 
The Examples which follow illustrate some of the results that have been 
obtained using representative levels of the plasticizer of the present 
invention.

EXAMPLES 1-13 
Catalyst Residue Removal 
The CO/C.sub.2 H.sub.4 copolymer or CO/C.sub.2 H.sub.4 /C.sub.3 H.sub.6 
terpolymer were suspended in hot acetyloacetone. The suspension was 
stirred for fifteen minutes at 120.degree. C. and quickly filtered without 
cooling. The polymer was then washed with cold acetyloacetone followed by 
acetone and vacuum dried. 
Sample Preparation 
The CO/C.sub.2 H.sub.4 copolymer or CO/C.sub.2 H.sub.4 /C.sub.3 H.sub.6 
terpolymer after catalyst residue removal was then added to an acetone 
solution of a modifier or modifier blend as described hereinafter and was 
dried with constant stirring to achieve good sample uniformity. Samples 
were then pressed into pellets which were then placed in the preheated 
testing chamber of a RHEOMETRICS RMS 800 rheometer. The rheometer is 
capable of measuring both components of complex viscosity (eta*), namely, 
the real (or loss) component (eta'), which can be correlated to the 
contribution of the viscous behavior of the material, and the imaginary 
(or storage) component (eta"), which can be correlated to the contribution 
of the elastic behavior. The character of the plots of both of these 
components versus time at a constant temperature provides information 
concerning the melting, softening or hardening of the material as well as 
its viscoelastic behavior. Each test was usually started at about 
200.degree. C., and the temperature was raised quickly to the preset 
level. The complex viscosity components were then measured. At first, a 
rapid drop in both components of complex viscosity was observed due to 
melting of the sample. With the exception of the pure CO/C.sub.2 H.sub.4 
copolymer, the storage component was lower than the loss component. This 
was followed by a time period with little or no viscosity change up to the 
point at which eta" become equal to eta' (gel point), and finally by an 
increase in the storage component (eta") of complex viscosity indicating 
crosslinking. 
A long time period to the gel point and a small plot slope were indicative 
of good sample stability. 
Data for the CO/C.sub.2 H.sub.4/C.sub.3 H.sub.6 terpolymer (POKC2C3) are 
listed in the Table: 
TABLE 
______________________________________ 
Tem- 
Sample per- Time to 
Example 
Composition ature gel point 
Slope 
# % .degree.C. 
sec Pa .times. sec .times. sec.sup.-1 
______________________________________ 
1 POKC2C3 100 237 330 0.58 
2 POKC2C3 95 235 318 0.79 
1035 5 
3 POKC2C3 90 235 456 0.30 
1035 5 
ERL 5 
4 POKC2C3 87.5 238 564 0.32 
1035 5 
ERL 5 
VL848 2.5 
5 POKC2C3 90 237 360 1.29 
1035 2.5 for - 680 sec 
ERL 2.5 then 0.24 
VL848 5 
6 POKC2C3 92.5 237 402 1.12 
1035 2.5 
ERL 2.5 
VL848 2.5 
7 POKC2C3 95 234 360 0.63 
1035 2.5 
ERL 2.5 
8 POKC2C3 90 238 500 0.20 
1035 5 
ERL 5 
9 POKC2C3 90 240 690 0.02 
1035 5 
EPR 5 
10 POKC2C3 90 240 500 0.03 
ESBO 5 
VL848 5 
______________________________________ 
ERL ERL4221: (3',4'-Epoxycyclohexylmethyl)3,4epoxycyclohexanecarboxylate 
VL848 Vanlube 848: Mixed octylated diphenylamine and diphenyl amine 
(&lt;7%). 
1035 Irganox 1035: Thiodiethylene 
bis(3,5di-tert-butyl-4-hydroxy)hydrocinnamate. 
EPR Epoxidized phenolic resin. 
ESBO Epoxidized soybean oil. 
The foregoing are intended to illustrate certain embodiments of the present 
invention and, for that reason, should not be construed in a limiting 
sense. The scope of protection sought is set forth in the claims which 
follow.