GB2348427A - Stabilised polyketone compositions - Google Patents

Abstract

A polymer composition comprises <SL> <LI>A) a major amount of a linear polyketone polymer <LI>B) boron impurities; and <LI>C) a minor amount of a stabilising additive which is selected from the group consisting of <SL> <LI>(i) zeolite-type aluminium silicates containing a cation of a metal of Group Ia of the Periodic Table of Elements and (ii) amorphous aluminosilicates containing a cation of a metal of Group Ia of the Periodic Table of Elements with the proviso that (i) and (ii) contain substantially no cation of a metal of Group IIa of the Periodic Table of Elements. </SL> </SL>

Description

STABILISED POLYMER COMPOSITIONS The present invention relates to a polymer composition comprising a major amount of a polyketone polymer and a minor amount of a stabilising additive.

For the purposes of this patent, polyketones are defined as linear polymers having an alternating structure of (a) units derived from carbon monoxide and (b) units derived from one or more olefinically unsaturated compounds. Although for the purposes of this patent polyketones correspond to this idealised structure, it is envisaged that materials corresponding to this structure in the main but containing small regimes (i. e. up to 10wt%) ofthe corresponding homopolymer or copolymer derived from the olefinically unsaturated compound, also fall within the definition. Such polyketones have the formula :

where the R groups are independently hydrogen or hydrocarbyl groups, and m is a large integer ; they are disclosed in several patents e. g. US 3694412. Processes for preparing the polyketones are disclosed in US 3694412 and also in EP 181014 and EP 121965.

The melt processing of polyketone polymers is known to be adversely affected by poor melt flow properties. Significant improvements in the flow properties of polyketone polymers have been achieved by adding thermal stabilisers to the melt.

According to US 5, 115, 002, melt stability of a polyketone polymer can be achieved by the addition thereto of a zeolite-type trivalent-metal silicate which contains a cation of an element of Group 2 of the Periodic Table. In contrast zeolite-type trivalentmetal silicates which contain cations of other elements, such as sodium and potassium, are said to destabilise polyketone polymers.

Surprisingly, it has now been found that zeolite-type aluminium silicates which contain a cation of a metal selected from Group la of the Periodic Table of Elements act as stabilisers for polyketone polymers which contain boron impurities. In addition, it has been found that amorphous aluminosilicates which contain a cation of a metal selected from Group Ia of the Periodic Table of Elements also act as stabilisers for polyketone polymers which contain boron residues.

Thus, according to the present invention there is provided a polymer composition comprising : A) a major amount of a linear polyketone polymer having an alternating structure of (a) units derived from carbon monoxide and (b) units derived from one or more olefinically unsaturated compounds ; B) boron impurities ; and C) a minor amount of a stabilising additive which is selected from the group consisting of (i) zeolite-type aluminium silicates containing a cation of a metal of Group la of the Periodic Table of Elements and (ii) amorphous aluminosilicates containing a cation of a metal of Group Ia of the Periodic Table of Elements with the proviso that (i) and (ii) contain substantially no cation of a metal of Group IIa of the Periodic Table of Elements.

Advantages of the composition of the present invention include improved melt stability, improved melt processability of the polymer composition in melt processing operations, and less discoloration of the polymer composition following melt processing.

The boron impurities may be of the general formula BArx (OH) (where Ar = is a substituted or unsubstituted aryl, x = 0 to 3, y = 0 to 3 and x + y = 3) and hydrates or alcoholates thereof. Examples of such species include boric acid, boronic acids and boronous acids.

The boron impurities may also be boron polyalcohol complexes. Examples of such impurities include complexes of boric acid with glycerol, mannitol or sorbitol.

Generally, the boron impurities are impurities which are derivable from boron containing co-catalysts. Suitably, the boron containing co-catalyst may be a conjugate base of a strong acid having a pKa of less than 6, such as HBF4. Alternatively, the boron containing co-catalyst may be a boron hydrocarbyl compound, for example, a boron alkyl or boron aryl compound. In particular, the boron hydrocarbyl compound may be a Lewis acid of the formula BXYZ where at least one of X, Y, and Z is a monovalent hydrocarbyl group. Where any one of X, Y or Z is a monovalent hydrocarbyl group, it is suitably an alkyl, for example, a C,-C6 alkyl group, or an aryl group, for example, a substituted or unsubstituted phenyl group, for example, C6H5 or C6F5. Other suitable monovalent hydrocarbyl groups are p-Hal-C6H4 (where Hal = F, Cl, or Br), m, m C6H3 (CF3) 2, CF3 and C2Fs. It is to be understood that two or three of the groups X, Y and Z can together form bi or trivalent groups respectively. At least one of X Y and Z is a monovalent hydrocarbyl group ; however, it is preferred that at least two, preferably three, of X Y and Z are each monovalent hydrocarbyl groups. Suitable examples of such Lewis acids are BMe3 (where Me = methyl), BEt3 (where Et = ethyl), B (C6H5) 3, B [m, m- (CF3) 2C6H3] 3, B (mesityl) 3, B (p-Hal-C6H4) 3 (where Hal = F, Cl or Br), B (m CF3C6H4) 3 and B (C6Fs) 3, preferably B (C6H5) 3, B (-Hal-C6H4) 3, and B (C6F5) 3. Where one or more of X, Y and Z is not a hydrocarbyl group, it is suitably a OH, OR (where R is an alkyl group, for example, a C,-C6 alkyl group) or halide group, preferably a halide group, for example, fluoride, chloride or bromide, especially fluoride. Examples of compounds where one of X, Y, or Z is a group other than a hydrocarbyl group are boronic acids of the formula RB (OH) 2 where R is a hydrocarbyl group e. g. PhB (OH) 2 (where Ph = phenyl), and hydrocarbyl 1, 3, 2-benzodioxaboroles.

Other suitable boron hydrocarbyl co-catalysts are borate salts of the formula MBR4 where M is an alkali metal e. g. Li, Na, and R is a hydrocarbyl group e. g. C6H5, C6Fs and substituted analogues. For example, a suitable compound could be LiB (C6F5) 4 or NaB (C6H5) 4.

Boron hydrocarbyl co-catalysts are described in detail in EP 0619335 and EP 0704471 which are herein incorporated by reference.

The boron impurities may also be boron a-hydroxy carboxylic acids. Thus, the boron impurities may be derivable from a source of an anion having the formula :

wherein the R groups are independently selected from the group consisting of C, to C6 alkylene groups, ortho-phenylene or biphenylene groups or substituted derivatives thereof or groups having the formula :

or substituted derivatives thereof.

Examples of suitable sources of an anion of the above formula are given in EP 0314309 which is herein incorporated by reference. In particular, the source of the anion may be H [B (OC6H4C02) 2].

Alternatively, the boron impurities may be derivable from a Group VIII metal complex of a phosphinite of formula (I) R'RzB (oPR32) 2.

Examples of complexes of formula (I) are given in EP 0735075 which is herein incorporated by reference.

Preferably, the polymer composition comprises less than 200 ppm, more preferably less than 20 ppm, most preferably, less than 5 ppm of boron impurities based on boron.

Generally, it will not be necessary to employ more than a certain amount of the stabilising additive to achieve an acceptable performance. Suitably, the stabilising additive of the invention is present in an amount of up to 20 parts per hundred (pph), more preferably 0. 01 to 3 pph and most preferably 0. 05 to 1 pph with respect to the polyketone polymer.

The zeolite-type aluminium silicates mentioned hereinbefore are to be understood as being materials which are aluminium silicates having a definite crystalline structure within which are a large number of small cavities which may be interconnected by a number of channels. These cavities and channels (pores) are uniform in size and the dimensions of these pores are such that they are able to accept for adsorption molecules of certain dimensions, so that these materials have also come to be known as"molecular sieves". The pore size of the zeolites of the invention is not an important parameter with respect to the stabilising activity. The pore size may be up to 1. 0 nm for conventional zeolites or may be in the range of 200 to 2000nm for mesoporous type zeolites.

Preferably, the zeolite-type aluminium silicate of the invention (hereinafter referred to as"zeolite") contains a cation selected from the group consisting of lithium, sodium and potassium.

The molar ratio of the amounts of silicon and aluminium present in the zeolite is not an important parameter with respect to the stabilising activity of the zeolites of the invention. Suitably the molar ratio of silicon to aluminium is in the range 1 to 10, more preferably in the range 1 to 7 and most preferably in the range 1 to 5.

The amount of the Group I cation in the zeolite of the invention is also not an important parameter with respect to the stabilising activity of the zeolites of the invention. A skilled person knows that the maximum amount of the cation of the Group la element which can be present in the zeolite is 1 gram atom per gram atom of aluminium. Preferably, the cation of the Group la element is present in an amount of at least 0. 2 gram atom per gram atom of silica and in particular in an amount of at least 0. 5 gram atom per gram atom of silica.

Preferably, the zeolite of the invention is represented by the following general formula for the unit cell : Mxt (AI02) x (SiO2) y]. wH20 where, M is cation of a metal of Group la of the Periodic Table of Elements, w is the number of water molecules per unit cell and x and y are the total number of A104 and Si04 tetrahedra per unit cell.

Examples of suitable zeolites include but are not limited to : zeolite 13X : Na86 [ (A102) 86 (Si02) io6]. 276H20 zeolite 4A : Nal2 [ (AI02) i2 (Si02) i2] 27H20 zeolite 3A : K6Na6 [ (AI02) 12 (SiO2) 12]. WH20 zeolite Y : Na56[(AlO2)56(SiO2)136]250H2O zeolite L : Kg [(AlO2) g (SiO2) 27]. 22H2O mordenite : Nas [ (AI02) 8 (Si02) 4o]. 24H20, and clinoptilolite : Na6 [ (AI02) (Si02) 3o]. 24H20 The zeolite of the invention may be based on a mineral or on a synthetic material.

It is known that a metal of Group la of the Periodic Table of Elements may be incorporated into the zeolite, for example, as the result of the synthesis of the zeolite in the presence of a suitable compound of the Group la metal, or as a result of impregnation of a zeolite or as a result of the modification of a zeolite containing the cation of another element, viz. by ion exchange (this method is described in US 5, 115, 002 which is herein incorporated by reference).

It is to be understood that the zeolite of the invention may contain trace amounts of a Group Ha metal.

The particles of the zeolites of the invention may be the particles as they are obtained in the synthesis of the zeolite or they may be obtained by milling larger particles, such as extrudates (as described in US 5, 115, 002). The size of the particles may be selected, for example, by sieving. Suitably, the maximum particle size of the zeolite is 50Rm, preferably less than 25um, more preferably less than 10fi, most preferably less than 5gm. Suitably, the average particle size ranges from 0. 0511m to 511m, most preferably from 0. lu. m to I gm.

The zeolites may be dried before blending with the polyketone polymer but they may also be used without prior drying (as described in US 5, 115, 002). Thus, the water content is not an important parameter with respect to the stabilising activity of the zeolites of the invention.

The amorphous aluminosilicates mentioned hereinbefore are porous silicates which are not zeolites. The pore size of the amorphous aluminosilicates of the invention is not considered to be an important parameter with respect to the stabilising activity.

Generally, an amorphous aluminosilicate has pore sizes in the range 2 to 1000nm.

The molar ratio of the amounts of silicon and aluminium present in the amorphous aluminosilicate is not an important parameter with respect to the stabilising activity. Suitably the molar ratio of silicon to aluminium is in the range 1 to 10, more preferably in the range 1 to 7 and most preferably in the range 1 to 5.

Preferably, the amorphous aluminosilicate is an amorphous sodium aluminosilicate. A suitable amorphous sodium silicate is sold by Degussa under the trade name P820.

It is to be understood that the amorphous aluminosilicates of the invention may contain trace amounts of a Group IIa metal.

Preferably, the stabilising additives of the present invention are washed before being blended with the polyketone polymer. Preferably, the washed stabilising additives are dried before being blended with the polyketone polymer.

As noted above for the purposes of this patent, polyketone polymers are defined as linear polymers having an alternating structure of (a) units derived from carbon monoxide and (b) units derived from one or more olefinically unsaturated compounds.

Suitable olefinic units are those derived from C2 to Cl2 alpha-olefins or substituted derivatives thereof or styrene or alkyl substituted derivatives of styrene. It is preferred that such olefin or olefins are selected from C2 to C6 normal (straight chain) alpha-olefins and it is particularly preferred that the olefin units are either derived from ethylene or most preferred of all from a mixture of ethylene and one or more C3 to C6 normal alphaolefin (s) especially propylene or butylene. In these most preferred materials it is further preferred that the molar ratio of ethylene derived units to C3 to C6 normal alpha-olefin derived units is greater than or equal to 1 most preferably between 2 and 30. Typically, the polyketone polymer will be a copolymer of ethylene/propylene/CO or ethylene/butylene/CO where the units derived from propylene or butylene are in the range 0. 5-10 mol % e. g. 6 mol % of the polyketone polymer.

The polyketone polymer will suitably have a number average molecular weight of between 20, 000 and 1, 000, 000 preferably between 30, 000 and 250, 000 for example 40, 000 to 180, 000.

Other polymers (for example, polyethylene, polypropylene, PVC, polystyrene and polyesters) may be blended with the polymer composition of the present invention ; the nature and amount of such a polymer will depend upon what modifications of the polymer properties are required. Where PVC is blended with the polymer composition of the present invention, the PVC is suitably stabilised with a conventional stabiliser package for PVC. Furthermore, the polymer compositions of the present invention may comprise one or more conventional polymer additives such as anti-oxidants, UV stabilisers, fillers, pigments, internal lubricating additives, external lubricating additives, mould release agents and further thermal stabilisers. Examples of anti-oxidants include hindered phenols and aromatic amines. Examples of further thermal stabilisers include hydroxyapatite and pseudo-boehmite. Examples of UV stabilisers include benzophenones, benzotriazoles and triazine compounds. Examples of pigments include carbon black and titanium dioxide. Examples of internal and external lubricants include fatty acids such as stearic acid, fatty esters such as glycerol mono-stearate and glycerol tri-stearate, fatty amides and bis amides such as stearamide, erucamide and ethylene bis stearamide, polyolefin waxes and oxidised polyolefin waxes. Examples of fillers include hydroxyapatite, talc, wollastonite, calcium carbonate, magnesium hydroxide, clay, and silica. The fillers may be surface treated, for example with an acidic substance such as stearic acid.

The stabilising additives may be added to the polyketone polymer by various continuous or discontinuous processes, for example, by dry blending and tumbling.

The polymer composition of the present invention can be processed into articles of manufacture such as fibres, films, laminates, tubes, piping and articles having an intricate shape (e. g. receptacles) by any melt processing technique, such as melt spinning, extrusion and co-extrusion, injection moulding and compression moulding.

According to a further embodiment of the present invention there is provided a process for stabilising a polyketone composition which comprises : adding a stabilising additive to a polyketone polymer which is obtainable by polymerising a mixture of carbon monoxide and one or more C2 to C, 2 alpha-olefins in the presence of a catalyst system comprising : (a) a source of a Group VIII metal ; (b) a bidentate phosphine ligand ; and (c) a boron containing co-catalyst wherein the stabilising additive is selected from the group consisting of (i) zeolite-type aluminium silicates containing a cation of a metal of Group la of the Periodic Table of Elements and (ii) amorphous aluminosilicates containing a cation of a metal of Group Ia of the Periodic Table of Elements with the proviso that (i) and (ii) contain substantially no cation of a metal of Group IIa of the Periodic Table of Elements.

Preferably, the source of the Group VEI metal compound is a palladium compound.

Suitably, the bidentate phosphine ligand is of formula (R') 2P-R-P (R') 2 wherein the Rl groups are independently selected from alkyl, cycloalkyl and aryl groups and R is a bridging alkylene group of the formula- (CH2), (CHR3b- where the R3 groups are independently hydrogen, methyl, ethyl or propyl groups and a and b are either zero or integers such that a+b is at least 2, preferably between 2 and 10. Preferably, the bridging alkylene group is selected from-(CH2) 2,-(CH2) 3-,-(CH2) 4-and-(CH2) 5-. Of these the most convenient species are the bidentate phosphines, 1, 2-bis (diphenylphosphino) ethane, 1, 3-bis (diphenylphosphino) propane and 1, 4-bis (diphenylphosphino) butane.

Alternatively, the bidentate phosphine ligand is of the formula (R') 2P-R2),-(PR3) NR2-P (R') 2 where each R'is independently an aryl, alkyl, alkoxy, amido or substituted derivative thereof, W is a hydrogen, a hydrocarbyl or hetero group, and R3 is a hydrocarbyl or hetero group. Suitable bidentate phosphine ligands of the formula R'zP- (NR2)x-(PR3)y-NR2-PR12 are described in WO 97/37765 which is herein incorporated by reference. Of these the most convenient species are (o-anisyl)2-X-P(o-anisyl)2 where X =- (CH2).- n = 2-4, or X = N (R) R = Cl-C6 alkyl or aryl.

The invention will now be illustrated by the following Examples.

Examples Melt Processing using a Brabender Plasticorder The polyketones employed in Examples 1 to 3 were melt processed using a Brabender Plasticorder laboratory batch melt mixer. The torque on the rotors of the mixer and the melt temperature were monitored over a period of 30 minutes. Melt processing was carried out using a rotor speed of 60 r. p. m. and an initial chamber temperature of 215 +/-2 C under a nitrogen atmosphere (achieved by passing nitrogen through the rotor shafts and over the top of the loading chute).

The various zeolites were nuxed with the polyketone powders in a beaker prior to melt processing. In addition, melt processing was carried out in the presence of 1 part per 100 parts of polyketone of an oxidised polyethylene wax (Irgawax 371, supplied by Ciba) which acts as a mould release agent.

On addition of the stabilised polyketone compositions to the batch melt mixer the torque rises as the polymer fuses. The torque drops within a few minutes as the polymer completely melts and the temperature equilibrates and then reaches a minimum value.

Without wishing to be bound by any theory it is believed that an increase in torque with time, beyond this minimum, is indicative of increasing viscosity owing to cross-linking reactions. A stabilising effect is manifested by a reduction in the rates of increase in the torque.

Determination of Melt Flow Rate The melt flow rate (MFR) of the polyketones was measured using a Davenport Melt Index Tester. Tests were carried out at a temperature of 240 or 250 C and an applied load of 1. 2. 2. 16 or 5 kg. The MFR was calculated from the mass of extrudate pushed through a die (2. 095 mm diameter) over a 30 second period on application of the load 3 or 4 minutes after charging the polymer into the barrel of the instrument at the test temperature. The test conditions used are specified in the Examples along with the values measured. Otherwise, standard MFR procedures were followed (e. g. ISO 1133).

Without wishing to be bound by any theory, a decrease in MFR of a given material after a processing history is indicative of increased viscosity owing to crosslinking reactions. A stabilising effect of an additive is evidenced by protection against or limitation of such a decrease in MFR.

Materials Zeolites Purmol 13 supplied by CU Chemie Uetikon AG : a 13X zeolite containing sodium cations ; nominal pore size of 0. 8 nm ; Si : AI = 1. 2 : 1 ; a 10% aqueous suspension has a pH of circa 11.

Purmol 13 washed : Purmol 13 was soxhlet extracted with distilled water for 24 hours and dried at a temperature of 200 C for 3 hours ; a 10% aqueous suspension of the washed material has a pH of circa 10.

Molsiv 13 supplied by UOP Limited : a 13X zeolite containing sodium cations ; nominal pore size of 1. 0 nm ; Si : AI = 1. 2 : 1 ; a 10% aqueous suspension has a pH of circa 10.

Molsiv 13 washed : Molsiv 13 was soxhlet extracted with distilled water for 24 hours and dried at a temperature of 200 C for 3 hours ; a 10% aqueous suspension of the washed material has a pH of circa 10.

Purmol 4 supplied by CU Chemie Uetikon AG : a 4A zeolite containing sodium cations ; nominal pore size of 0. 4 nm ; Si : AI = 1 : 1 ; a 10% aqueous suspension has a pH of 11 to 12.

Purmol 4ST supplied by CU Chemie Uetikon AG : a 4A zeolite containing sodium cations ; a version of Purmol 4 having reduced alkalinity-a 10% aqueous suspension has a pH of 10 to 11.

3A zeolite supplied by Aldrich : a 3A zeolite containing both potassium and sodium cations ; nominal pore size 0. 3nm ; Si : AI = 1 : 1 ; a 10% aqueous suspension has a pH of circa 11.

3A zeolite washed : 3A zeolite was soxhlet extracted with distilled water for 24 hours and dried at a temperature of 200 C for 3 hours ; a 10% aqueous suspension of the washed material has a pH of circa 11.

Zeolite Y supplied by Aldrich : a zeolite Y containing sodium cations : Si : AI = 2. 4 : 1 : a 10% aqueous suspension has a pH of circa 10.

Zeolite Y washed : Zeolite Y was soxhlet extracted with distilled water for 24 hours and dried at a temperature of 200 C for 3 hours ; a 10% aqueous suspension of the washed material has a pH of circa 9-10.

Amorphous aluminosilicates P820 supplied by Degussa : pore sizes in the range 2 to 1000nm ; Si : AI = 5 : 1.

P820 washed : P820 was soxhlet extracted with distilled water for 24 hours and dried at a temperature of 200 C for 3 hours ; a 10% aqueous suspension of the washed material has a pH of circa 10.

Comparative zeolites Molsiv 5 supplied by UOP Limited : a 5A zeolite which may be represented by the formula CaNasKAlOSiOnLwHxO ; nominal pore size of 0. 5 nm ; Si : AI = 1 : 1 ; a 10% aqueous suspension has a pH of circa 10.

Molsiv 5 washed : Molsiv 5 zeolite was soxhlet extracted with distilled water for 24 hours and dried at a temperature of 200 C for 3 hours ; a 10% aqueous suspension of the resulting washed material has a pH of circa 10.

Example 1 An ethene/propene/CO polyketone (PK1) was prepared using a complex of palladium diacetate with 1, 3-bis (diphenylphosphino) propane (catalyst) and a borosalicylic acid co-catalyst. PK1 was found to have a melting point of 202 C (defined as the peak of the melting endotherm on second heating measured by differential scanning calorimetry at a heating rate of 10 C/min) and a melt flow rate of 32 g/10 minutes (measured at a temperature of 240 C after 3 minutes under an applied load of 5 kg). Table 1 shows the results obtained when PK1 was melt processed (as described above) with various zeolites. The results show an improvement in melt stabilisation in the presence of zeolites containing a sodium cation.

Table I Melt Processing PKI (Borosalicylic

Resultant Minimum Final MFR at Additive Loading Torque Torque Final Melt 240 C/5kg (pph) (Nm) (Nm) Temp. C (g/lOmin.) None 4. 2 7. 8 219 no flow Purmol 13 0. 1 3. 9 5. 7 214 2. 8 0. 3 4. 0 5. 4 214 8. 9 0. 5 3. 7 4. 6 214 10 1. 0 3. 9 5. 0 214 12 2. 0 4. 5 5. 6 213 12 3. 0 4. 0 4. 7 213 11 Purmol 13 0. 5 3. 8 4. 8 213 12. 5 washed 1. 0 3. 5 4. 4 213 14 2. 0 3. 6 4. 4 213 16 3. 0 3. 9 4. 4 214 16 Molsiv 13 0.3 3.2 4.6 215 7. 5 1. 0 3. 2 4. 4 216 13. 5 2. 0 3. 8 4. 6 212 14. 5 Purmol 4 0. 3 3. 6 5. 3 216 4. 3 1. 0 4. 0 5. 2 216 5. 6 2. 0 4. 0 5. 3 216 3. 9 3. 0 4. 1 5. 5 217 3. 3 Purmol 4ST 0. 3 4. 5 6. 7 216 1. 7 1. 0 4. 0 5. 3 214 5. 8 2. 0 3. 8 4. 8 213 8. 0 3. 0 4. 1 5. 1 212 8. 7 Molsiv 5 0, 3 3. 9 7. 1 216 no flow 1. 0 3. 6 6. 8 219 1. 0 Example 2 An ethene/propene/CO polyketone (PK2) was prepared using a complex of palladium diacetate with 1, 3-bis (diphenylphosphino) propane (catalyst) and a borosalicylic acid co-catalyst. The polyketone was found to have a melting point of 203 C (defined as the peak of the melting endotherm on second heating measured by differential scanning calorimetry at a heating rate of 10 C/min) and a melt flow rate of 31 g/10 minutes (measured at a temperature of 240 C after 3 minutes under an applied load of 5 kg). Table 2 shows the results obtained when PK2 was melt processed (as described above) with various zeolites. The results show an improvement in melt stabilisation in the presence of a zeolite containing a sodium cation.

Table 2 : Melt ProcessinBorosalicvlic Acid Residues)

Resultant Minimum Final MFR at Additive Loading Torque Torque Final Melt 240 C/5kg (pph) (Nm) (Nm) Temp. ( C) (g/lOmin.) None 4. 0 6. 3 216 4. 7 Purmol 13 0. 05 3. 8 4. 6 216 10. 5 0. 1 3. 7 4. 3 218 12 0. 3 4. 0 4. 6 214 15 0. 5 3. 8 4. 3 213 15 1. 0 3. 7 4. 3 215 13. 5 2. 0 3. 8 4. 3 215 11 Example 3 An ethene/propene/CO polyketone (PK3) was prepared using a complex of palladium diacetate with 1, 3-bis (diphenylphosphino) propane (catalyst) and trispentafluorophenyl boron co-catalyst. PK3 was found to have a melting point of 201 C (defined as the peak of the melting endotherm on second heating measured by differential scanning calorimetry at a heating rate of 10 C/min) and a melt flow rate of 32 g/lOmin (measured at a temperature of 240 C after 3 minutes under an applied load of 5 kg) Table 3 shows the results obtained when PK3 was melt processed (as described above, except that the Brabender temperature was 210 C) with various zeolites. The results show an improvement in melt stabilisation in the presence of a zeolite containing a sodium cation.

Table 3 Melt Processing PK3 (Trispentafluorophenyl Boron Residues)

Resultant Minimum Final MFR at Additive Loading Torque Torque Final Melt 240 C/Skg (pph) (Nm) (Nm) Temp. ( C) (g/lOmin.) None 4. 2 5. 8 213 5. 1 1 Molsiv 13 0. 3 4. 1 4. 3 212 19. 5 1. 0 3. 5 3. 9 214 15. 5 Example 4 An ethene/propene/CO polyketone (PK4) was prepared using a complex of palladium diacetate with bis (di (2-methoxyphenyl) phosphino) methylamine (catalyst) and triphenyl boron and HBF4 co-catalysts. PK4 was found to have a melting point of 215 C (defined as the peak of the melting endotherm on second heating measured by differential scanning calorimetry at a heating rate of 10 C/min) and a melt flow rate of 61 g/10 minutes (measured at a temperature of 250 C after 4 minutes under an applied load of 2. 16 kg).

PK4 powder was mixed with the selected zeolites in the amounts given in Table 4. In addition, all formulations contained 0. 1 pph Irganox 1010 (a phenolic antioxidant supplied by Ciba). The polymer compositions were melt compounded on a 16mm twin screw extruder using a die temperature of 230 C. The MFR of the resultant melt processed compositions were determined after residence times of 4, 8 and 12 minutes in the barrel of the melt index tester (at a temperature of 250 C and under an applied load of 2. 16 kg). Without wishing to be bound by any theory, retention of melt index with dwell time is indicative of a stabilising effect.

The results given in Table 4 show an improvement in melt stabilisation in the presence of a zeolite containing sodium or potassium cations and in the presence of an amorphous sodium aluminosilicate.

Table 4 : Melt Processing PK4 (Triphenvl Boron and HBF4 residues

Melt Flow Rate at 250 C/2. 16kg (g/lOmin.) Loading Additive (pph) 4 min 8 min 12 min None 58 33 18 Purmol 13 0. 1 61 47 40 0. 3 63 50 38 1. 0 59 44 36 Molsiv 13 0. 1 61 51 39 0. 3 60 55 48 1. 0 61 55 47 Molsiv 13 0. 3 66 57 49 washed 1. 0 66 56 48 Purmol 4 0. 3 58 42 30 1. 0 49 31 14 Purmol4ST 0. 1 59 46 38 0. 3 60 51 40 1. 0 59 47 38 zeolite 3A 0. 1 60 43 27 0. 3 59 43 27 1. 0 47 26 7. 5 zeolite 3A 0. 3 61 45 34 washed 1. 0 62 50 40 zeolite Y 0. 1 55 35 17 0. 3 60 35 24 1. 0 60 49 38 Table 4 : Melt Processing PK4 riphenvl Boron and HBF4 Residues (continued)

zeolite Y 0. 3 56 37 21 washed 1. 0 60 48 39 Molsiv 5 0. 1 59 36 25 0. 3 55 31 18 1. 0 61 47 35 Molsiv 5 0. 3 56 31 18 washed 1. 0 62 44 33 P820 0. 3 56 37 21 1. 0 47 23 4 P820 0. 3 63 43 29 washed 1. 0 58 41 29 Example 5 An ethene/propene/CO polyketone (PK5) was prepared using a complex of palladium diacetate with 1, 3-bis (diphenylphosphino) propane (catalyst) and triphenyl boron and HBF4 co-catalysts. PK5 was found to have a melting point of 220 C (defined as the peak of the melting endotherm on second heating measured by differential scanning calorimetry at a heating rate of 10 C/min) and a melt flow rate of 61 g/10 minutes (measured at a temperature of 250 C after 4 minutes under an applied load of 1. 2 kg). PK5 was blended with various zeolites in the amounts given in Table 5. In addition, all formulations contained 0. 1 pph Irganox 1010 (a phenolic antioxidant supplied by Ciba). The polymer compositions were melt compounded on a 16mm twin screw extruder using a die temperature of 225 C. The MFR of the resultant melt processed compositions were determined after residence times of 4, 8 and 12 minutes in the barrel of the melt index tester at a temperature of 250 C and under an applied load of 1. 2 kg. Without wishing to be bound by any theory, retention of melt index with dwell time is indicative of a stabilising effect.

Table 5 : Melt Processing PK5 (Triphenvi Boron and HBF Residues

Melt Flow Rate at 250 C/2. 16kg (g/lOmin.) Loading ~ Additive (pph) 4 min 8 min 12 min None 57 35 15 Molsiv 13 0. 3 67 55 45 1. 0 71 61 51 The results presented in Tables 1 to 5 show that zeolites containing sodium or potassium ions are effective as melt stabilisers for polyketones containing boron residues. In addition, the results presented in Tables 1 and 4 show that zeolites containing sodium or potassium ions are more effective as stabilisers for polyketones containing boron residues than a zeolite containing a Group II cation. Furthermore, the effectiveness of the zeolites according to the present invention is in some cases enhanced by a reduction of the alkalinity of the zeolite, for example, by a mild washing treatment with water.

Claims (1)

1. Claims : 1. A polymer composition comprising : A) a major amount of a linear polyketone polymer having an alternating structure of (a) units derived from carbon monoxide and (b) units derived from one or more olefinically unsaturated compounds ; B) boron impurities ; and C) a minor amount of a stabilising additive which is selected from the group consisting of (i) zeolite-type aluminium silicates containing a cation of a metal of Group Ia of the Periodic Table of Elements and (ii) amorphous aluminosilicates containing a cation of a metal of Group la of the Periodic Table of Elements with the proviso that (i) and (ii) contain substantially no cation of a metal of Group IIa of the Periodic Table of Elements.