CA2176937A1 - Polyketone polymer composition - Google Patents

Abstract

Cross-linkable and cross-linked compositions comprising a major amount of polyketone polymer and a minor amount of an iodide salt. Compositions containing a iodide salt which is an onium iodide salt of nitrogen, phosphorus, arsenic, or a combination thereof of which the cation coordination sphere is shielded by aromatic substituents, or an alkali metal iodide show improved oxidative stability.
Further, the invention relates to a process for preparing such compositions and to a process for cross-linking such compositions.

Description

~WO95/14056 2 1 76937 r~l/rl,."-3~51 POLYKETONE POLY~ER COMPOSITION
The present invention relates to polyketone polymer compositions.
Polyketone polymers eYhlbit many desirable physical properties which make them suit~ble for ~n51n~r;n~ ~hf~rm^Fl~ctic applications.
In particular, high molecular weight linear alternating polyketone polymers possess such properties as high strength, rigidity, toughness, chemical resistance, and wear properties. While these properties are adequate for many applications it would be o~ advantage to further improve certain properties such as envi ~:~1 stress crack resistance, chemical resistance, creep resistance, increased use temperature and increased tensile strength. One method known in the ~rt for providing these 1 ~ ts has involved the cross-linking of linear polymer chains of a thl.r~7rl ~ctiC polymer. An example of this is polyethylene which can be made to exhibit increased durability, use temperature and Jtrength through post-reactor cross-linking.
In order to maintain good melt proc~ h1 1 1 ty and flow during part fabrication it is generally desirable to utilize polymers of substantially linear molecular structure before cross-linking.
Therefore, it is particularly desirable to have a simple procedure which can cross-link the substantially linear polymer after melt Fro~ s1 n~. Cros5-linking a polymer after melt processing is useful in m~1n~:~1n~n~ a high degree of cry5tallinity in the final part and allows common methods of melt fabrication such as injection moulding, extrusion, and blow moulding to be used.
The present invention relates to a composition, r1.~1ng a major amount of polyketone polymer and a minor amount of a iodide salt with the proviso that the composition is not a composition containing 5 . 0 parts per million by weight of sodium iodide, metal content on polymer. It ha5 been found that such composition can be cross-linked to give a composition having and exhibiting improved 2 1 7 6 9 3 7 PcTlEp94lo3~sl ~

mechanical and chemical resistant properties. Further, the present invention relat~s to blends ~nntA;n;nq such composltion.
The polyketone polymers which are useful in the practice of the invention are of a linear alternating structure and contain substantially one molecule of c~rbon monoxide for each molecule of ethylenically unsaturated hydrocarbon. The preferred polyketone polymers are copolymers of carbon monoYide and ethylene or terpolym~rs of carbon monoxide, ethylene and a second ethylenically unsaturated hydrocarbon of at least 3 carbon atom5, particularly an ~c-olefin such as propylene.
When the preferred polyketone terpolymers are employed a~ the m~or polymeric component of the blends of the invention, there will be within the terpolymer at least 2 units incorporAtinq a moiety of ethylene for each unit incorporating a moiety of the second hydrocarbon. Preferably, there will be from 10 units to 100 units incorporating a moiety of the second hydrocarbon. The polymer chain of the preferred polyketone polymers i5 therefore represented by the repeating formula -[--CO--(--CH2--CH2--)-]X--[CO--(-G)--]-y where G is the moiety 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 0.5. When copolymers of carbcn monoxide and ethylene are employed in the compositions of the invention, there will be no econd hydrocarbon present and the ~5 copolymers are represented by the above formula wherein y is zero.
When y is other than zero, i.e. terpolymers are employed, the --C0-(-CH2-H2-)- units and the --CO-(G-)- units are found randomly throughout the polymer chain, and preferred ratios of y:x are from 0. 01 to 0 .1. The precise nature of the end groups does not appear to influence the properties of the polymer to any ~nne;~-rAhle extent so that the polymers are fairly represented by the formula for the polymer chains as depicted above.
of p~rticular interest are the polyketone polymers of number average molecular weight from 1000 to 200, 000, particularly those of 3~ number average molecular weight from 20, 000 to 90, 000 a~ determined ~ WO 95ll40S6 ~ 2 ~ 7 6 9 3 7 r~
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 n2ture of th~ proportion of the second hydrocarbon pr~sent. Tvpical melting point5 for the polymers are from 175C to 300C, more typically from 210C to 270C. Preferably, the polymer~
have a limiting viscosity number ~LVN), measured in m-cresol at 60C
in a st~ndard capillary viscosity measuring device, from O.S dl/g to lO dl/g, more preferably from 0 . 8 dl/g to 4 dl/g.
A preferred method for the production of the polyketone polymers has been described in EP-A-18101~, EP-A-24E483, EP-A-600554, EP-A-314309 and EP-A-391579.
The useful iodide salts are tho5e which are capable of cross-linking polyketone polymers under appropriate conditions. Examples of these salts include those listed in Table 1.
Linear polyketone polymers aontaining a sufficlent (minor) ~mount of iodid~ salt can be cross-linked by sub~ecting the composition to the presence of oxygen at el~vated temperature.
While not wanting to be held to any p2rticular theory, it is believed that some oYiddtion of the polyketone polymer occurs which in the presence of a iodide salt catalyzes the cross-linking reaction. The eYtent of cross-linking is rrntrollAhl~ by the amount of eyposure to hcat and oxygen. The time required to obtain a desired level of cross-linking is inversely related to the temperature used or the oxygen content available. An effective oxygen source is air. The amount of heat r~quired is that which is ~ufficient to lead to the cro5s-linking of the polymer. The required amount of heat can be obtained at a preferred operating temper~ture of about 70C. While the inventive process can cross-link a polyketone polymer melt in the presence of sufficient oxygen, it is generally preferred to cross-link at temperatures below the crystalline melting point of the polymer.
Methods known in the art for cro5s-linking polyethylene include ~1) the use of high energy radiation, ~2) ~hPrmrrh~mical reactions, 35 and ~3) moisture induced reactions. Methods ~1) and ~2) rely on the W0 95/14056 2 1 7 6 q 3 7 ~ 8S1 initiation of free-radical intermediates either through radiation or radical initiators such ~a organic peroxide5. In polyethylene these radical intermediates re5ult in chemical cross-links between polymer chains; however, these methods are not applicable to all polyolefins. Polypropylene and polybutylene are examples where radical initiation does not result in cros5-linking, but rather chain scission. These methods also possesS certain disadvantages which are known to the skilled artisan.
The method of cross-linking polyethylene which utilizes moisture first requires free-radical grafting of vinyl silane unlts onto the polyolefin which are then cspable of reacting with water to produce chemiczl cross-links. Since cros5-linking occurs after melt processing, this method like radiation curihg, allows conventional fabric~tion methods to be used and maintains a high degree of crystallinity after cross-linking.
The above m~thods are not entirely suitable for polyketone polymers. Radiation curing is not possible because chain scission reactions can occur in polyketone5 . Th~rm~ h~; cal cross-linking processes which involve adding enough heat to c~use the subst~ntially llnear polymer to melt and flow into a desired form just as cross-linking occurs are also not suitable. First, the processing temperatures of polyketone5 are ~ n~ rAh1 y higher than in polyethylene which would re5ult in the premature decomposition of ~ny free-r~dic~l initiators ~organic peroxides). Second, unlike 2~ simple polyolefins, th~ reactivity of polyketone5 is more diverse ~nd can lead to unwanted free radical ~ rA~ n reactions of the polymer ~
Moisture cross-linking of polyketon~ polymer m_y be possible if silane grafting could be carricd out by 50me mean5 other than a free-radic~l proces5. It i5 envi5ioned that a 5ilane grafting method ~or polyketones is fea5ible if the vinyl groups commonly used in polyethylene were replaced with groUps capable of reacting with ketone5 such as amine5. Examples would include (trialkylsilyl)-alkylamines and ~tri~lkylsilyl) aryl-amines.
The current invention takes a line~r polymer which is ~ WO 95/14(~56 2 1 7 6 9 3 7 p~rl L~o~lTI
s completely soluble in HFIPA (hexafluoroisopropanol) and cross-links it such that it becomes only swollen by the solvent.~ One method known for d~t rr;nin7 the extent of cross-Linking is by measuring its solubility or 9T ~ 11 rl~; 1; ty in a suitable solvent . Suitable solvents are usually polar solvents with low molar volume, especially those having a strong hydrogen bonding r-hArA~-t~ri qtic.
Examples of such solvents include h~-v7fl1~rQ-isopropanol, m-cresol, and phenol. heYaflUoroiSOprOpanOl is preferred because of its ability to dissolve the polyketone polymer at room t~r~r~rAt~re.
Furthermore, it has s~rrr1~;n~1y been found that compo~itions ntA;n;n~ certain iodide salts, show improved oxidative stability.
A disadvantage of linear alternating polymers of carbon monoxide and at least one ethylenic~lly unsaturated hydrocarbon is that they can exhibit a ~i~t~.rlorAtl~n of physical properties upon thermal oxidative ~ rA~ t~n. ~his degradation i5 due to a chemicAl attack of atmospheric oxygen on the polymer chains and is ~hArA~-t~-r1 ctic of most, if not all organic polymer6 . Oxidation is typically autocatalytic and occurs as a function of heat and oxygen, hence the term thermal oxidative degradation. It is desirable to inhibit the deterior~tion of polymer properties by st7h; 1; 7~ng the polymer toward the adver~e effect5 of heat and oxyg~n. There are a large number of thermal oxidative 9tAh; 117 rc which are employed commercially to 5tabilize th~rm~riA~tic polymer5 against such degradation. however, m_ny of the thermal 5t:~h; 1; 71.rc which are known to be effective with polyol~fins, polyamide5, polyacetals, polyacrylates, etc. are only marginally or not at all effective when employed with polyketone polymers.
An oxidatively 5tabilized polyketone polymer compo5ition has now been found. ~he composition compri5es an onium iodide salt of nitrogen, phosphorus, arsenic, or combination thereof in which the cation coordination sphere is 6hielded by aromatic substituents or an alkali metal iodid~, with the proviso that th~ composition is not a composition containing 5. 0 ppmw of sodium iodide, m~tal content on polymer. In 13P-A-600554 it has b~en described that the melt stability of polymers can be adversely affected by the W O 95114 0~ 6 2 1 / 6 q 3 7 r ~ ~ " ~ ~ ~ A C ¦
preaence of alkali (ne earth) metal 5alts. In experiment l has been described a composition r~ntA;ninAj S.0 parts per mi~`lion by weight of sodium iodide, metal content on polymer~
The composition of the present invention can be prepared by rnntArtinrJ the polyketone polymer with the iodide salt. More ~rer;f;rA11y, the methods can comprise a) melt . ;n1 after rrntArt; nrJ thc iodide salt with polyketone polymer by powder mixing or solvent deposition, b) diffusion of the iodide salt into polymer articles by treating the polymer with a solution containing the iodide ~zlt, preferably using a solvent which has some mi~cibility with both polymer and the iodide salt, or c) in-situ generation of the iodide salt utilizing a polymer blend comprising of precursors which upon application of a sufficient ~mount of heat generates the iodide salt. Preferably, the iodide salt is introduced by diffusion.
Thermzl oxidative ~ rA~lAtirn of organic polymers relates to the deterioration of polymer properties due to the chemical reaction(s) between the polymer and atmospheric oxygen. While oxidation processes are complicated and mechanistic pathways of A~O oxidation between different polymers may vary, oxidation is generally promoted by heat, often initiated by trace ilDpurities such a~ metal ions or organic }~ , and rhArArt~r;
overall as autocatalytic in which ci~rbon radicals and peroxyl radic~ls constitute key; nt~. ' ' At~ in the catalytic cycles .
~5 Consumption of oxygen by the polymer propagates the catalytic cycle and gener~tes oxygenated ~pecies which either comprise part of the polymer or are evolved as gaseous products. These oxygenzted species may further be prodegradztive to the polymer.
For example, hydroperoxides are not inherently stable and are capable of ~' -;nAJ into new radicals, either thermally or catalyzed by tr~ce impurities, which can then initiate additional oxidative cycles.
For polyketones it is believed that the thermal oxidative proc~ss involves the formation of oxygenates which under aging conditions cleave polymer chains and result in a reduction of -~ WO 95/14a56 ~ 1 7 6 9 3 7 F~
molecular weight and a loss of polymer ~nr~n71 ~_~nt . Ultimately this results ln a deterioration of polymer mec_dnic~l propcrtieS
such as reduced impact strength, 109s of elongation at break, and embrittlement. It would therefore be advantageous to stabilize the poly}:etone polymers towards the5e property losses either by reducing their overall rate of oxidation or reducing thelr rate of polymer chain scission.
The iodide salt- which are especially useful in thermal oYidative stabilization, have been described in Table l.

Iodide Salts S~:~hi1i71n~ Iodide S~lts Non-srAhi1;7in7 Iodide salts Tetrapheny1rh~crh^n1um PPh4+ ZnI~ - Zinc iodide Bis~triphenylrhn~rh^r.~nylidene) CaI2 - Calcium iodide ammonium Ph~P=N+=PPh ~
Insitu Et4NI - tetraethyl-4-iodophenyltriphenylrh^crh^ni ammonium iodide PPh3 + 1<~ _ ~31 PPh or l,4-bis(triphenylrh^~rh^nium)benzene p* pl ~3 1' PPh2 Me4NI - tetramethyl-~onll~ io~d~

WO95/14056 2 1 7 6937 r~ 3~
TABLE 1 (Cont'd~
S-methyl-3- (methylthio) -1, 4-diphenyl lH-1, 2, 4- PPh3MeI - Methyltri-~r; ~7nl i phenylrhn~rhnni iodide ~J~,CH2 CH4 S \~
9-phenanthryl triphenyl rhn~rhnn; PMe (OPh) 3I - Methyltri-phenoxyrhnsphnn i idodide PPh4Cl - Tetraphenyl-phosphonium chloride RI (diffusion only) 1 PPh4Br - Tetraphenyl-rhnsFhnn j bromide 1 Other alkali metal iodide salts such as lithium, potassium and sodium iodide are also within the scope of the invention.
The iodide salts will generally be present in an amount within the rany~ of from 0.0001 to 10, more 5pecifically 0.001 to 10 percent based on the weight of the polyketone polymer, preferably in the range of from 0.1 to 1.0 percent based on the weight of polyketone polymer.
Further, it wa5 found that an improved oven aginq performance of the polymer is obtained if not orly the iodide sDlt is present, but also a hindered phenol, more specifically a composition, wherein the hindered phenol is benzene propanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy octadecyl e5ter and/or benzenepropanoic acid 3,5-bis(1,1-dimethylethyl)-4-hydroxy-1,2-ethanedyl bis (oxy-2, l-ethanediyl) ester.

~WO9S/14056 21 76937 P_-/C~51,'A'~Q~;1 _, 9 _ After preparatlon, the now stabili~ed polykctone polymers show improved retention of desired mechanic~l properties, such as resistance to embrittlement when tested under conditions of elevated trr~ r~t~lre 2nd air exposure. The test as disclosed in U.S. Pztent Uo. 4,994,511 subjects polymer samples to aerobic oven aging at various temperatures and monitors the time until brittle failure (cracking) occurs when sharply bent at an angle of 180.
The following eYamples and tables further lllustrate the various aspects of the invention.
EXA~PLF S ON STASI~IZATION
Polymera used in the following example5 are deacribed in Table 2. An oven aging test was used throughout the examples to distinguish the performanc~ of polymer additives. In this test, pol~mer sheet of 5.1 x 10-4 or 7.6 x 10-4 m (20 or 30 mil) thicknesses was prepared either by melt extrusion or compression moulding. Test specimens were then eut into 1 cm wide strips and placed into forced air circulating ovens at 100 C or 125 C.
Periodically, the strips were withdrawn from the oven and when cooled bent to ~ 150-degree angle. When the samples becam~
~ufficiently brittle to break under this te5t procedure it was considered to be a failure and the time to embrittlement was recorded .

21 76q37 WO 95/14056 F.~ I/n3~
--. 10 --Table 2. Polyketone polymers used in illustrative eYamples.
LVN Tm Base Polymer dl/g C Form Additivesb A 1.95 220 Ext. Sheeta 0.5~ Irganox 1330d 0.5~ Nucrel 535e B 1.86 220 Ext. Sheeta 0.29~ Irganox 1330d 0.29O CaHApC
0 . 3~ Nucrel S3se C l. 77 220 Powder 0 . 2~ Irganox 1330d O . 29~ CahAp 0 . 3S Nucrel 535e D 1.73 220 Powder 0.2~ Irganox 1330d 0 . 2 ~ CaHAp 0 . 3S Nucrel S3se E l. 87 220 Powder None ~Extruded sheet of 5.1 x 10-4 m ~20 mil) thickness.
bPercent b~sed on weight oS polyketone polymer.
CC~lcium HydL~ y~ te.
d 4, 4 ', 4"- [ (2, 4, 6-trimethyl-l, 3, 5-~n7~.r~rl yl) tris-(methylene) ] tris [2, 6-bio (l, l-dimethylethyl) -phenol3 epolymer of ethene with 2-methyl-2-propenoic acid.
Examples l-5 Examples 1-5 d~ OLL~Le the utility of iodide additives to heat aging when diff~ n~ y incorporated into polyketone polymer. Test specimens were prep2red by immersing polymer A in the form of 5.1 x 10-4 m (20 mil) sheet lnto a water compositlon for 20-25 min at a temperature of 90-9SC. The water used was HPLC
grade, OmniSolv supplled by EM Science. Water compositions used in examples 2-5 included: water alone, 0.30 wt~ ZnI2, 2.0~ ~I, and saturated Ph4PI which is only 5paringly soluble in water at 90-95 C. After exposure, the polymer specimens were cooled, W0 95/14056 ~ L'~ _ l wiped clean of any surfac~ resldue, and dried in a vacuum oven at 50 C with a nitroqen purge over night. One centimetre wide oven test strips were then cut fro~ the exposed sheets. For the sample which wa~ exposed to Ph4PI, neutron ~ctivation tests were conducted to determine the iodide pr~sent in the polymer after this expo3ure. Residual iodine measured ca. 900 ppm, calculating to 0.33~ Ph4PI present in this sample. Results of oven aging tests are shown in Table 3.
TA3I.E 3. Iodide additives rl~ff~ct~nAlly incorporated into polyketone polymer.
Days to Failure Example EYposure 125 DC 100 C

3 H70/ZnI7 21 3 S H70/Ph4PI 45 234 EYamples 2 and 3 show that simply exposing the polymer sheet to water alone or to a Jolution of ZnI2 does not result ln improved heat stability. Exposure to ~I and Ph4PI results in an improvement in heat stability with Ph4PI being far superior in its ~bility to stabilize thi5 polyketone polymer - greater than 2 times the control, Ex3mple 1.
Examples 6-10.
Test Jpecimens used in Examples 6-10 were ~llff~ nAlly prepared and then tested as described in Examples 2-5 using polymer A and water compositions which contained 2. 0~ of the rr~rr~.cp~nril n~ test additive. The results are _ rl 7~ in Table 4.

WO 9S/14056 2 1 7 6 q 3 7 r~ 3~CI
TABLE: 4. Onium iodide salt addltives ~'iff~ nAlly'`incorporated into polyketone polymer.
Day~ to Failure Example Expoaure 125 C 100 C

7h70/Ph4PBr 21 113 8h70/Ph4PC1 25 llO
9~170/Et4NI 26 117 h70/Ph4PI 44 245 Examples 7, 8, & 10 show that of the Ph4P halide salts only the iodide is 5 ~:~h; 1 i 7; nq to polyketone polymers . ExAmple 9 demonstrates that alkyl ammonium iodides such as tetr2ethyl-alomonium iodide (Et4NI~ are not effective in s1~~hil;7in~
polyketone polymers. This demonstrates that not all onium iodide salts are effective as s~Ahi 1 i 7~.r~ for polyketone polymer Examples 11-13.
Examples 11-13 were prepared as described in Example 1-5 with the exception th~t extruded ~heet of polymer E~ wzs used instead o~
polymer A. Test specimens for examples 12 & 13 were prepared imilar to Exampl~s 7-10. Oven ~glng results are shown in Tz~ble 5.
TABLE 5 . ~- ~ ri ~ln of iodide salts ~I; ff~ n:ll l y added to polyketone polymer.
Days to Failure Example Expo~ure 125 C lOO C

12 ~170/CaI7 l9 96 13 h70/Ph4PI 28 128 The~e examples show once again that not all iodide salts are ~ WO 95/14056 2 1 7 6 9 3 7 r~ R~I
s1-:~hi 1 i 7i ng to polyketone polymer. Calcium iodide shows no improvement in time to embrittlement over the control.
Examples 14 - 16.
Exampl~s 14-16 demonstrdte that powder mixing of Ph4PI and polyketone polymer followed by melt processing results in a polymer composition with improved thermal oxidative stability.
~xamples lS and 16 were prepared by combining 100 grams polymer C
powder with Ph4PI powder and then ~ , ; 7; n~ by tumbling overnight. Each mixture was then extruded on a lS mm E~aker-Perkins twin screw extruder oper~ting at a melt ~ ror:~t~lre of ~bout 250 C. The extruded compositions were then used to make plaques of 30 mil thicknesses by compression moulding. As shown in Table 6, compositions with Ph4PI showed significantly improved time to embrittlement at 125 C over the control.
TA3LE 6. Aging performance o~ Ph4PI melt blended into polykotone polymer .
Days to Failure Example Additive 125 C

lS 0.25~ Ph4PI 18 16 0.50~ Ph4PI 17 Ex~mpl~s 17 - 26.
Examples 17-26 compositions were pr~pared by melt processing ~s described in F,xamples 14-16 with the exception that polymer D
was used instead of polymer C. Oven aging test results shown in Table 7, illustrate that onium iodide salts with alkyl ~ubstituents (ex. 18-22) exhibit no srAh;117;n~ influence on polyketone polymers. Examples 25 and 26 demonstr~te the stAh; 1; 7; nq influence of iodide salts other than Ph4PI which also contain onium cations shielded by aromatic substituents, i.e.
bis~triphenylrhn5~hnrAnylidene)ammoniUm and a ~r;A7nl; salt, resp~ctively. In these exampl~s, the increased stability was WO95/14056 ~ ~ 7 6937 ~ t'- I ~
~omewhat ~mall, but simil~r in magnitude to the benefit from Ph4PI
in this polymer, Example 24.
Table 7. Aging r~.rfnrr-n~-o of onium iodide 5alts melt blended into polyketone polymer.
Days to Failure Example Additive 125 C 100 C

18 0 . 43~ Ph~MePI 16 48 19 0.49~ (PhO)~MePI Not processable 20 0.28% Et4NI 12 30 21 0. 50~ Et4NI 12 32 22 0.223 Me4NI 11 30 24 0.3~ Ph4PI 26 25 0. 43~ PPNIa 25 26 0.25ê TIb 27 a bis(triphenylrhnsphnrAnylidene)ammonium iodide b S-Methyl-3-(methylthio)-1,4-diphenyl-1H-1,2,4-tr~A.nli iodide Examples 27-39.
Examples 27-39 compositions were prepared by melt processing as described in Example5 14-16 using the polymers and additives ~ .nt~fi~l in Table 8. Example 30 demonstrates the improved resistance to embrittlement using only PPh4I. Example 31 shows a signific~nt improvement when a commercial hindered phenolic Ant;nY;olrnt such as Irganox 1076 is combined with Ph4PI in poLyketone polymers. This combination re5ults in improved oven aging performance compared to using either individually. Examples 33-39 demonstrate that in-situ formation of rhn~irhnn; iodides from a phosphine and an organic iodide ~ improves the stability of polyketone polymer ~ust as effectively as osing ~ WO9S/14056 21 76937 r~ e3~
-- .15 --Ph4PI. Examples 3~-37 shOW that the use o~ either triphenyl phosphine or 1,4-~ alone do not contribute to the atability of polyketone polymers. However, the combination of these additlves in Example 33 yields a polymer with significantly improved heat aging performance. Examples 38 and 39, further show the b--n~f; ~ 1 effect when an organic iodide and triphenyl-phosphine are combined in the additive package.
TABLE E. Aging performance of rhn~phnni iodides melt blended into polyketone polymers and generat~sd in-situ.
Example Polymer Additive Days to Failure 27 E None 15 28 E O.Sd Irganox 1076a 19 29 - E 0 . 5~ Irganox 245b 26 E 0.3~ Ph4PI 38 31 E 0.5~ Irganox 1076D, 0.3~ Ph4PI 43 32 E 0.5~ Irganox 24sb, 0.3~ Ph4PI 36 33 E 0.29~ PPh3, 0.39~ PhI2, 0.5~
Irganox 245b 42 34 E 0.3~ PPI7, 0.5~ Irganox 245b 11 36 D 0.2~ PPh~ 13 37 D 0.33 PP~ 15 38 E 0.5~ Irganox 24sb, 0.3~ 9-; O~lnph~n~nShrene 26 39 E 0. 5~ Irganox 24sb, 0 . 39a 9-iodophenanthrene, 0.2~ PPh~ 38 a n-o ctadecyl 3- ( 3, S-di -te rt-butyl - 4 - hydroxyphenyl ) propi ona te b 3,5-bis~l,l-dimethylethyl)-4-hydroxy-1,2-ethanediylbis(oxy-2,1-ethancdiyl)benzene propanoic acid ester.
-WO95/14056 ~ I / 6937 r~ o3x~
EXAMPLES ON CROSS--LIN~ING
Example Polyketone polymer A with a melting point of about 220 C and limitlng viscosity number of 1.87 dl/g was ' ' with 0.3 wt~
tetraphenylrh~-rh~nium iodide (PPh4I) and 0.5~ Irganox 1076 on a 15 mm 3aker Perkins extruder operAted at a melt t~mperatur~ of approximately 250 C. A control wa8 prepared by extruding polymer A
as described above without the use of any additives. After this, the pellets were dried in a vacuum oven at 50 C under nitrogen and then compression moulded into 5.1 x 10-4 m ~20 mil) thick plaques.
Test specimens were cut from the plaques in 1 cm wide strips and exposed to oxygen and heat using a Blue M forced air oven set at 125 C. The samples were withdrawn from the oven after ll days exposure and submitted for GPC analysis using hexafluoroisopropanol (HFIPA) as solvent. GPC analysis utilized ZORBAX 1000 and 60 PSM
columns in series and a Waters 410 differertial r~fr:~rt ~r as detector .
Table l shows that as expected of linear polyketone polymers, both unexposed samples were completely soluble in hFIPA. After exposur~ to heat and oxygen, polyketone polymers without iodide additives are soluble and exhibited a molecular weight loss. The polymer sample ''I'nt:-;n;n-J iodide became a swollen gel (50~ sol) indicAtive of a cross-linked polymer. This sample, however, did not ~rr~r; ~ embrittlement in the same oven until 43 days compared to the specimen without PPh4I which embrittled in only ~5 days.

~ WO 9S/14056 2 1 7 6 9 3 7 r~ Ql8C~

Table 2. PPh4I Promoted Cross-linking of Polyketone Polymer Molecular PPh4I Days e Weight Content 125C (Mn) None 0 55900 None 11 34510 0.3~ 0 55280 0. 34 11 Insoluble Example 2 Polyketone polymer B, with a melting point of about 220C, an LVN o~ 1.95 dl/g, and ~ nr~inin~J 0.5~ IrganoY 1330 and 0.5~
Nucrel 535, was melt extruded into S.l x 10 4 m (20 mil) sheet. One centimetr~ wide strips of this sheet were exposed to heat and oxygen a~ descrlbed in Example 1. In addition to these strips, a separate ~et of strips was submitted to a saturated aqueous PPh4I solution at 85 C for 20 min. The strips were removed, wiped clean, and then dried in a vacuum oven at 50 C under nitrogen purge. These strips r~nl~s~in;ng PPh4I by diffusion were then exposed to heat and oxygen as described above. Table 2 shows that after heat exposure the polyketone polymer with iodide was again an insoluble swollen gel (209~ sol) in BFIPA, while the s2mple without iodide treatment was completely soluble and displayed a loss in molecular weight. This 1~ example shows that iodide can be added after part fabrication but before heat and oxygen is applied to yield a cross-linked polyketone .

WO 95/140~6 ~; 7 6 9 3 7 r~
Table 3. n; ff~ n71 Treatment of Polyketone Parts with PPh4I
Molecular Weight PPh4I Treatment Days 1~ 125C (Mn) No 0 50562 No 5 34660 Yes S Insoluble Example 3 Polymer strips containing either potassium iodide or tetr2ethylammonium iodide were prepared and tested as described in Example 2 with the exception that 2 wt~ of the respect iodide solutLons were replaced for the PPh4I solution. It was observed that after 10 days at 125 C both samples were insoluble in HFIPA.
This demonstrates that iodides other than PPh4I also promote oxidative curing of polyketones.
Example 4 Polyketone polymer C, melting point of about 220C and ~VN of 1. 84 dl/g, was injection moulded into 1/8 inch ASTM D-638 tensile b~rs. Part of the bars were exposed to h~at and oxygen for 20 days as describe in Example 1, while a separate set was first treated with a saturated aqueous solution of PPh4I at 80 C for 90 minutes before heat exposure. Table 3 shows the tensile property, GPC, and DSC results before and after heat exposure. GPC was measured both on the skin and core of the tensile bars, while DSC was measured on the skin. This example shows that PPh4I promotes oxidative cross-linking which provides greater tensile strength and soLvent resistance while maintaining a high degree of crystallinity.
Thi~ example demonstrates that PPh4I promotes oxidative cross-linking which provides greater tensile strength and solvent resistance while m7;ntA;nin~ a high degree of crystallinity. Cross-linking, as indicated by ;n~ hll;ty in HEIPA, is demonstrated only in the sample 1-~nt7~n;nq PPh4I combined with sufficient exposure to heat and oxygen, i.e. the outer portions of the sample. As a res~lt ~ WO 95/14056 2 1 7 6 9 3 7 PCTIEP941038~1 -- .19 --of cross-linking, the PPh4I-~ nt ~ n7 sample shows ~ 24~ incre~se in yi~ld strength, while the specimen without PPh4I exhibits oxidatiYe degradation re3ulting in a loss of yield and molecular weight (40~ drop in number ~ver~lge molecular weight (Mn) of s)cin).
Cross-linking in the manner described did not diminish the extent of crystallinity relative to the uncross-linked polymer as apparent in the large heat of fusion values which are a proportional measure to the extent of crystallinity.

WO 95/140~6 2 1 7 6 9 3 7 P~ , 1,'Q3~

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Claims (13)

C L A I M S

1. Composition comprising a major amount of polyketone polymer and a minor amount of a iodide salt with the proviso that the composition is not a composition containing 5.0 parts per million by weight of sodium iodide, metal content on polymer.

2. Composition according to claim 1, in which the polyketone polymer is a linear alternating polyketone polymer.

3. Composition according to claim 1 and/or 2, in which the iodide salt is an onium iodide salt of nitrogen, phosphorus, arsenic or a combination thereof, in which the cation coordination sphere is shielded by aromatic substituents, or an alkali metal iodide.

4. Composition according to claim 3, in which the iodide salt is selected from the group of tetraphenylphosphonium 5-methyl-3-(methylthio)-1,4-diphenyl 1H-1,2,4 triazolium, bis (triphenylphos-phoranylidene)ammonium, 4-iodophenyltriphenylphosphonium, 1,4-bis (triphenylphosphonium)benzene and 9-phenanthryl triphenyl-phosphonium.

5. Composition according to claim 4, in which the iodide salt is tetraphenylposphonium iodide.

6. Composition according to any one of claims 3-5, which composition further comprises a hindered phenol.

7. Composition according to claim 6, wherein the hindered phenol is benzene propanoic acid 3,5-bis(1,1-dimethylethyl)-4-hydroxy octadecyl ester and/or benzenepropanoic acid 3,5-bis (1,1-dimethyl-ethyl)-4-hydroxy-1,2-ethanediyl bis (oxy-2, 1-ethanediyl)ester.

8. Composition according to any one of claims 1-7, wherein the iodide salt is present in an amount of from 0. 0001 to 10 wt%.

9. Composition according to any one of claims 1-8, which composition has been cross-linked.

10. Process for preparing a composition, which process comprises contacting a polyketone polymer with a iodide salt with the proviso that the iodide salt is not sodium iodide.

11. Process for preparing a composition according to claim 9, which process comprises treating the polyketone polymer with a solution containing the iodide salt.

12. Process for cross-linking a composition as described in any one of claims 1-8, which process comprises subjecting the composition to the presence of oxygen at elevated temperature.

13. Blend comprising a composition according to any one of claims 1-9.