WO1999016822A1

WO1999016822A1 - Polypyrrols obtained from polyketones and aromatic amines

Info

Publication number: WO1999016822A1
Application number: PCT/EP1998/006244
Authority: WO
Inventors: Joseph Michael Machado
Original assignee: Shell Internationale Research Maatschappij B.V.
Priority date: 1997-10-01
Filing date: 1998-09-30
Publication date: 1999-04-08

Abstract

A method of palsticizing a polyketone polymer comprising mixing the melt of the polyketone polymer with a plasticizing quantity of an amine of the general formula: R?1-R-NR2R3¿ wherein R is a phenylene group, R1 comprises a substituted or unsubstituted C¿2-20? aliphatic group and R?2 and R3¿ are independently hydrogen or a C¿1-3? aliphatic alkyl group; a polymer composition; and a thermoplastic pyrrolic polymer.

Description

POLYPYRROLS OBTAINED FROM POLYKETONES AND AROMATIC AMINES

This invention relates to polyketone polymers. More particularly, this invention relates to plasticized polyketone polymers and their production.

Polymers of carbon monoxide and olefinic monomers, generally referred to as polyketone polymers or aliphatic polyketone polymers, are well known in the art. The class of alternating polymers of carbon monoxide and at least one olefinic monomer are of particular interest among polyketone polymers. This class of polymers is disclosed in numerous U.S. patents, exemplified by U.S. Patents Nos . 4,880,865 and 4,818,811, which are incorporated herein by reference.

Polyketone polymers exhibit considerable stiffness. While stiffness is desirable in many applications, some polyketone applications call for reduced stiffness to produce a more flexible product. Applications calling for such a product are, for example, fuel lines, tubing, engine hoses, electrical hoses, cable tire, electrical strapping, gaskets and seals in the automotive industry. One approach to increasing the flexibility of polyketone polymer is to modify the polymer through the employment of a plasticizer. Traditional plasticizers are diluents having a low molecular weight relative to the polymers comprising the matrix to which they are added. In addition to increasing the flexibility of the polymer they may also impart improved processability, improved low temperature performance, and increased toughness .

The degree to which plasticizers can be used to achieve these types of effects varies widely depending upon the polymer involved. This is so because plasticizers may work according to a number of different mechanisms. The plasticizer may ease the movement of one macromolecule over another thereby reducing intramolecular friction and reducing the polymer' s resistance to deformation. Alternatively, the plasticizer may ease resistance to deformation by solvating and thereby breaking a number of points of attachment of one polymer molecule to another along the length of the polymer chains. Yet another means of plasticization involves a dynamic equilibrium of attachment and detachment (via solvation) of plasticizer and polymer molecule which leads to a changing degree of aggregation and disaggregation of the polymer molecules. The free volume available to a polymer may also be increased by the addition of a plasticizing substance. This is greatly dependent upon the nature of the plasticizer. The size and shape, charge distribution, amenability to hydrogen bonding, density, and other characteristics of the plasticizer molecule all come into play with these mechanisms.

Another factor in plasticizer selection is compatibility. In this context, compatibility refers predominantly to the solubility of the plasticizer in the polymer matrix. In addition to solubility, reactivity may be a measure of suitability for plasticization. That is, a reactive plasticizer may be used. This approach has the advantage of resisting extraction of the plasticizer from the polymer matrix. However, merely covalently bonding various groups onto the polymer backbones or functional groups attached thereto will not necessarily provide the plasticizing results that are sought as the solubility, degree of polarity, and a number of other characteristics of the polymer may be affected by such reactions. U.S. Patent 5,115,002 proposes the use of polyketone additives comprised of zeolytes and, optionally, aromatic amines as stabilizers for polyketones. The patent refers generally to the use of aromatic amines as stabilizers. U.S. Patent 5,019,614 proposes the use of aniline- substituted triazine compounds as UV stabilizers for polyketones. In all cases the amino group of the aniline contains a bulky triazine substituent and the phenyl portion is substituted in a number of positions with a variety of substituents . U.S. Patent 4,795,774 proposes that aromatic amines can be used to stabilize polyketones against oxidative degradation. The patent proposes a broad range of aromatic amines in this capacity from unsubstituted aniline to randomly substituted naphtha- lenic amines. In each of the foregoing patents, stabilizing quantities of the additives are mixed with the polyketones. This is less than 10% wt, with quantities less than 5% wt being preferred in most cases. U.S. Patent 3,979,374 discloses thermoplastic pyrrolic polymer compositions and a method for making them by an acid catalysed reaction of a primary mono- a ino compound with a polyketone polymer in a solvent. It is said that the selection of the primary mono-amino compound has a significant effect on the properties of the polymer composition, and that when the primary mono- amine is a primary alkyl mono-amine the resulting polymer has elastomeric properties.

It has now surprisingly been found that a plasticized polyketone polymer composition can be made by modifying a polyketone polymer in the melt with a phenylamine (i.e. an aniline) which is substituted at the phenyl ring with an aliphatic substituent. This is a surprising result because primary alkyl amines of up to 20 carbon atoms were found to cause severe melt degradation of the polyketone upon contacting the polyketone melt with the amine .

It was further found that upon contacting the polyketone melt with the phenylamine a grafting reaction may take place whereby at least a part of the amine reacts with the polyketone. The occurrence of a grafting reaction depends on the structure of the phenylamine. A primary amine forms a pyrrole type structure and a secondary phenylamine forms a Schiff' s base. A tertiary amine may not be reactive, but still it plasticizes the polyketone polymer. The advantage of the grafting reaction is that the phenylamine becomes chemically bound to the polyketone polymer chains and it therefore will better resist extraction from the polymer. The present invention relates to a method of plasticizing a polyketone polymer comprising mixing the melt of the polyketone polymer with a plasticizing quantity of an amine of the general formula R!-R-NR2R3 wherein R is a phenylene group, R1 comprises a substituted or unsubstituted C2-20 aliphatic group and R^ and R3 are independently hydrogen or a Cι_3 aliphatic alkyl group.

The invention further relates to a polymer composition which is obtainable by the method of plasticizing of this invention.

The invention also relates to a thermoplastic pyrrolic polymer which is obtainable by reacting a polyketone which is a copolymer of carbon monoxide and an olefinic monomer with an amine of the general formula R!-R-NR2R3 wherein R is a phenylene group, Rl comprises a substituted or unsubstituted C2-20 aliphatic group and R^ and R3 are hydrogen, and which comprises in a random distribution ketonic units of the general formula -CO-CC- and pyrrolic units of the general formula CC

^■C -CC—

N

R in which general formulae CC represents a 1,2-ethylene group originating from the ethylenic unsaturation of the olefinic monomer. The 1,2-ethylene groups may be substituted or unsubstituted, dependent of the structure of the olefinic monomer.

The polyketones for use in this invention are in particular alternating polymers of carbon monoxide and at least one olefinic monomer (i.e. an organic compound, typically a hydrocarbon, having an ethylenically unsaturated portion) . That is, the alternating polymer contains one molecule of carbon monoxide for each molecule of olefinic monomer in alternating sequence. The term "polyketone" also refers to copolymers, terpolymers, etc., i.e. polyketones made from various numbers of olefinic monomers.

Olefinic monomers have typically up to 20 carbon atoms. They may comprise heteroatoms, for example oxygen and nitrogen, such as in methyl methacrylate, vinyl acetate and N-vinylpyrrolidone . Preferably the olefinic monomers are hydrocarbons, for example aliphatic, cycloaliphatic or aromatic hydrocarbons. Examples are hexene-1, 4-methylpentene-l, cyclopentene and styrene. Preferably the hydrocarbonaceous olefinic monomer is an α-olefin. The preferred polyketone polymers are copolymers of carbon monoxide and ethylene or copolymers of carbon monoxide, ethylene and an additional olefinic monomer of at least 3 carbon atoms, particularly an α- olefin such as propylene or butene-1.

When the preferred polyketone polymers are employed as the major polymeric component of the blends of the invention, there will be within the polymer at least

2 units incorporating a moiety of ethylene for each unit incorporating a moiety of a further olefinic monomer, if present. Preferably, there will be from 10 units to 100 units incorporating a moiety of the further olefinic monomer. The polymer chain of the preferred polyketone polymers is therefore represented by the repeating formula :

where G is the moiety of an olefinic monomer of at least 3 carbon atoms polymerized through the ethylenic unsaturation and the ratio of y:x is no more than 0.5, typically from 0.01 to 0.1. When copolymers of carbon monoxide and ethylene are employed in the compositions of the invention, there will be no additional olefinic monomer (s) present and the copolymers are represented by the above formula wherein y is zero. When y is other than zero, the -CO-G- units are found randomly throughout the polymer chain. 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 chains as depicted above.

The polyketone polymers of number average molecular weight from 1000 to 200,000, particularly those of number average molecular weight from 20,000 to 90,000, as determined by gel permeation chromatography, are of particular interest. The polyketone polymers are typically linear polymers. Typical melting points for the polyketone polymers are from 175 °C to 300 °C, more typically from 210 °C to 270 °C, as determined by differential scanning calorimetry. The polymers have typically a limiting viscosity number (LVN) , measured in m-cresol at 60 °C in a standard capillary viscosity measuring device, from 0.5 dl/g to 10 dl/g, more typically from 0.8 dl/g to 4 dl/g.

The polyketones of this invention can be prepared by polymerizing the monomers in the presence of a Group VIII metal/bidentate ligand catalyst. Preferred methods for the production of the polyketone polymers are illustrated by U.S. Patents Nos . 4,808,699 and 4,868,282, which are herein incorporated by reference. U.S. Patent No. 4,808,699 teaches the production of alternating polyketones by contacting an olefinic monomer and carbon monoxide in the presence of a catalyst comprising a Group VIII metal compound, an anion of a non-hydrohalogenic acid with a pKa less than 6 and a bidentate phosphorous, arsenic or antimony ligand. U.S. Patent No. 4,868,282 teaches the production of linear alternating terpoly ers by contacting carbon monoxide and ethylene in the presence of one or more further olefinic monomers with a similar catalyst.

The plasticized compositions of the invention comprise the polymers described above intimately mixed with a plasticizing quantity of an amine. As used throughout this specification, "plasticizing quantity" is defined as a quantity of plasticizer sufficient to decrease the stiffness (as measured by the flexural modulus) of the polyketone by at least 20% of that of the same polyketone without the presence of the amine. However, it is preferred that sufficient amine be employed to reduce the stiffness by more than 40%. For practical purposes no more amine will typically be employed than needed to reduce the stiffness by 90%. The quantity of the amine mixed with the polyketone can vary within wide limits and the properties of the resulting composition will depend in part upon the quantity of the amine it contains. The addition of amine in quantities of more than 10% by weight to 50% by weight (based on the weight of the total composition) will result in the desired property modification of the polyketone polymer. The mixture and reaction of amine in quantities of greater than 10 %wt to 30 %wt (based on the total weight of composition) is preferred with loadings about 15-30% by weight being most preferred.

The plasticizers of this invention may be reactive plasticizers. By "reactive," "reacting," or "reacted" it is meant that to a significant degree, the means by which the amine and the polyketone are compatibilized is through covalent bonding. That is, the compatibility of the amines of this invention with the polyketone may result largely from chemical rather than physical interaction with the polymer matrix. Typically, at least 30 %-mole of the amino groups of the amine employed react with the polyketone backbone.

The pyrrolic polymer of this invention may contain the pyrrolic units and the ketonic units in any suitable ratio. Typically the molar ratio of the pyrrolic units to the ketonic units is between 0.1:100 and 20:100, preferably between 0.2:100 and 15:100, in particular between 0.5:100 and 10:100.

When reactive amines are employed, the nucleophilic nitrogen atoms of the amines are attracted to the electrophilic carbons of the polyketone carbonyl groups.

Employing the R, R¹, R^ and R³ groups as described below provides the plasticizer with a suitable degree of reactivity/nucleophilicity and reduces the stiffness of the polymer with which it is reacted. For reactivity of the amine and the polyketone, the group R preferably contributes to the nucleophilicity of the amino nitrogen or at least not unduly inhibits it. That is, it preferably has a neutral or electron donating, as opposed to withdrawing, inductive character.

The skilled man will appreciate that the inductive character can be influenced by group R^ and any further substituents attached to the group R. It is preferred that R! and any further substituents at R are positioned at the para-position or at a meta-position relative to NR2R3. Substituents at an ortho-position may cause steric hindrance to the reaction of the amine and the polyketone. Preferably R! and NR2R3 are the sole substituents to R and they are typically positioned in a para-position relative to each other.

Groups R! which comprise substituted or unsubstituted C2-20 aliphatic groups are considered to be effective, preferably the aliphatic group does not contain a cyclic structure. Linear or branched chains of carbon atoms are suitable.

R! is preferably selected so as not to render the amine non-reactive or insufficiently reactive. Suitable groups R^ are, for example, C2-2O' ^or preferably C2-10 ester, alkyl, ether, thiol, thioether, amide and urethane groups. Any such functional group (i.e. the ester, ether, etc. group), if present, is preferably situated directly adjacent to the group R, linking an aliphatic hydrocarbyl group of R^ to the group R. C-l-12 ester groups and η-12 alkyl groups are more preferred. Cg ester groups and C 2 alkyl groups are most preferred. The carbon numbers quoted include the carbon atoms attached to heteroatoms. Any other substituent to the group R may be of a similar nature as the Group Rl, but they contain in general a small number of carbon atoms. Typically they contain 1-3 carbon atoms .

It is possible to employ amines having small substituted or unsubstituted N-alkyl substituents. It is preferred that the total number of carbon atoms comprising R2 or R3 does not exceed 4. In reactive amines typically at least one of R^ and R3 is hydrogen, preferably R^ and R3 are hydrogen.

The polyketone polymer melt and the amine can be mixed according to generally known methods of mixing polymers and additives. When plasticizing polyketone polymer according to this invention, use of a twin screw compounding extruder with injection capability is preferred. For example, a 30 mm or 25 mm counter- rotating intermeshing extruder is suitable for this purpose. When the amine is a liquid it can be injected into the polyketone melt during extrusion. If the amine is a powder or other solid it is preferred that the polyketone and amine are mixed with polyketone powder and then extruded. For example, a ground polyketone is tumble mixed with the solid amine, and then extruded. Most preferably, melt mixing temperatures at least 20 °C below the boiling point of the amine are maintained. A vacuum devolatizing section downstream of the plasticizer injection port is also preferred on the compounding extruder.

The plasticized compositions of the invention may also contain other conventional polymer additives which improve or otherwise alter the properties of the compositions, such as fillers, extenders, lubricants, pigments, stabilizers, impact modifiers, and other polymeric materials. Such additives may be added to the composition by blending or by other conventional methods. The plasticized polyketone compositions of the present invention are excellent in their level of stiffness, their strength and impact resistance, in particular their impact resistance at -30 °C. They may find use as tubing, such as automotive fuel line tubing; engine hoses; electrical strapping, such as for electrical cable; gaskets; and seals.

The following non-limiting examples further illustrate the invention. In each example, weight percent is on the basis of the weight of the total composition (polyketone polymer and additives) unless otherwise indicated.

Example 1 (Polyketone Formation)

A terpolymer of carbon monoxide, ethylene, and propylene was produced in the presence of a catalyst composition formed from palladium acetate, the anion of trifluorocetatic acid, and 1, 3-bis (diphenylphosphino) - propane. The melting point of the linear terpolymer was 220 °C and it had a limiting viscosity number (LVN) of 1.8 measured at 60 °C in m-cresol.

Example 2 (Formation of Plasticized Polyketone Composition)

The polymer of Example 1 was cryogenically ground. The cryoground polymer was then cooled with liquid nitrogen to form a coarse powder and tumblemixed with ethyl para-aminobenzoate, as plasticizer, to form a mixture comprising about 80 wt% polyketone and about 20 wt% plasticizer. This mixture was then melt mixed into pellets using a 30 mm co-rotating twin screw extruder. This melt mixed combination was then injection moulded to produce standard specimens for ASTM D638 and ASTM D790 tensile and flexural testing. About 40% of the amine reacted with the polyketone. The remainder co patibilized via physical effects. Example 3 (Formation of Plasticized Polyketone Composition)

The polyketone of Example 1 was cryogenically ground and mixed with 2-ethylhexyl para-aminobenzoate, as plasticizer, in the manner described in Example 2. The composition of the mixture was about 80 wt% polyketone and about 20 wt% plasticizer. The composition was mixed for 10 minutes and then melt mixed into pellets using a twin screw extruder. The composition was then injection moulded into standard test specimens as described in Example 2. About 40% of the amine reacted with the polyketone. The remainder compatibilized via physical effects . Example 4 (Formation of Plasticized Polyketone Composition)

The polyketone of Example 1 was cryogenically ground and mixed with para-dodecylaniline, as plasticizer, in the manner described in Example 3. The composition of the mixture was about 90 wt% polyketone and about 10 wt% plasticizer. The composition was powder blended and then melt mixed into pellets using a twin screw extruder. The composition was then injection moulded into standard test specimens as described in Example 2. In excess of 90% of the plasticizer reacted with the polyketone. Example 5 (Physical Testing)

Physical testing was conducted on the standard test specimen produced in Examples 1-4. Tensile and flexural properties were determined according to ASTM D638 and ASTM 790. Results are listed in Table 1. Table 1

This example shows the significant reduction in modulus attained through the use of the plasticizers of this invention. Example 6 (for comparison)

Example 4 was repeated with the difference that tridecylamine was used instead of para-dodecylaniline . Severe melt degradation of the polyketone occurred, such that pelletizing was not possible. Example 7 (for comparison)

Example 4 was repeated with the difference that a mixture of Ci4__]_g alkylamines, available under the tradename ADOGEN 140, was used instead of para- dodecylaniline. Severe melt degradation of the polyketone occurred, such that pelletizing was not possible.

Claims

C L A I M S

1. A method of plasticizing a polyketone polymer comprising mixing the melt of the polyketone polymer with a plasticizing quantity of an amine of the general formula R!-R-NR2R3 wherein R is a phenylene group, R^ comprises a substituted or unsubstituted C2-20 aliphatic group and R and R3 are independently hydrogen or a C_]__3 aliphatic alkyl group.

2. A method as claimed in claim 1, wherein R¹ and NR2R3 are the sole substituents to R.

3. A method as claimed in claim 1 or 2, wherein R! and NR2R3 are positioned in a para-position relative to each other.

4. A method as claimed in any of claims 1-3, wherein the polyketone polymer is an alternating copolymer of carbon monoxide and an olefinic monomer.

5. A method as claimed in claim 4, wherein the olefinic monomer is ethene or ethene and an additional olefinic monomer of at least 3 carbon atoms, such as propene or butene-1.

6. A polymer composition which is obtainable by a method of plasticizing as claimed in any of claims 1-5.

7. A thermoplastic pyrrolic polymer which is obtainable by reacting a polyketone which is a copolymer of carbon monoxide and an olefinic monomer with an amine of the general formula R!-R-NR2R wherein R is a phenylene group, Rl comprises a substituted or unsubstituted C2-20 aliphatic group and R2 and R3 are hydrogen, and which pyrrolic polymer comprises in a random distribution ketonic units of the general formula -CO-CC- and pyrrolic units of the general formula

R in which general formulae CC represents a 1,2-ethylene group originating from the ethylenic unsaturation of the olefinic monomer.

8. A polymer as claimed in claim 7, wherein the molar ratio of the pyrrolic units to the ketonic units is between 0.2:100 and 15:100.

9. A polymer as claimed in claim 8, wherein the molar ratio of the pyrrolic units to the ketonic units is between 0.5:100 and 10:100.