WO2007002585A1

WO2007002585A1 - Copolymers of c10+ alpha olefins with other alpha olefins and method for copolymerization

Info

Publication number: WO2007002585A1
Application number: PCT/US2006/024804
Authority: WO
Inventors: Tze-Chiang Chung; Han Hong; Robert Wen Lee
Original assignee: Shell Internationale Research Maatschappij B.V.
Priority date: 2005-06-28
Filing date: 2006-06-26
Publication date: 2007-01-04

Abstract

The present invention provides a process for the copolymerization of C10+ alpha olefins which comprises copolymerizing a C10+ alpha olefin with another alpha olefin in the presence of a constrained geometry metallocene catalyst and a cocatalyst. The present invention also provides copolymers of ethylene and 1-decene.

Description

COPOLYMERS OF C₁₀₊ ALPHA OLEFINS WITH OTHER ALPHA OLEFINS AND METHOD FOR COPOLYMERIZATION

Field of the Invention

The field of this invention is the copolymerization of alpha olefins and copolymers of Ci₀₊ alpha olefins with lower carbon number alpha olefins. Background of the Invention

Processes and catalysts for the production of copolymers of ethylene and/or propylene and other alpha olefin comonomers are numerous and very well known. Linear low density polyethylene (LLDPE) polymers comprised of ethylene and either 1-butene, 1-hexene or 1-octene have been sold commercially for many years. There have been some suggestions that LLPDE polymers could be made with Cχo₊ alpha olefin monomers.

Attempts to design a practical process for polymerizing ethylene, for instance, with long chain alpha olefins such as 1-decene have been unsuccessful. For example, the literature article by Seppala, "Copolymers of Ethylene with Butene-1 and Long Chain α-01efins . I . Decene-1 as Long Chain α-01efin, " Journal of Applied Polymer Science, Vol. 30, pp. 3545-3556 (1985) describes attempts to incorporate sufficient amounts of 1-decene into ethylene copolymers in order to make an ethylene/1-decene copolymer which had properties different from the base polyethylene polymer. In the article, a Ziegler Natta catalyst of titanium chloride and triethylaluminum was used for the polymerization and it was found that incorporation of 1-decene into the copolymer was at about the 2% wt. level, wherein the melting point, density, crystallinity, and M_v are all higher than those of the 1-hexene and 1-octene copolymers made the same way, and the DSC curve was said to be characteristic of linear polyethylene. Table II of the article shows that the incorporation of 1-decene into the copolymers was not nearly as much as the amounts of 1-hexene and/or 1-octene which were incorporated into the copolymers.

Thus, it can be seen that it would be advantageous to provide a method for producing into ethylene or other lower molecular size alpha olefin copolymers with 1-decene or higher carbon number alpha olefins. Summary of the Invention

The present invention provides a process for copolymerizing do₊ alpha olefins with lower carbon number alpha olefins to produce copolymers with high molecular weight. The process can achieve high incorporation of the C₁₀₊ monomer into the copolymer. The present invention provides such a process which comprises copolymerizing a Ci₀₊ alpha olefin with a lower carbon number, preferably C₂-g, most preferably C₂~8, alpha olefin in the presence of a catalyst composition comprising a) a constrained geometry metallocene and b) a cocatalyst. It is preferred that the metallocene be a single-site constrained geometry metallocene.

The C1₀₊ alpha olefin copolymers of this invention may have a viscosity molecular weight (M_v) of from 14,000 to 500,000, preferably from 14,000 to 100,000, most preferably from 14,000 to 60,000. The amount of the C₁₀₊ alpha olefin monomer in the copolymers may range from 0.5 % mol (mole percent) to less than 100% mol, preferably from 0.5 to 20, more preferably from 1 to 15, most preferably from 1.5 to 10. Brief Description of the Drawing

Figure 1 is the DSC melting temperature curve for the copolymer described in Table 3 below.

Figure 2 illustrates the comparison of comonomer incorporation mole% (top) and weight% (bottom) among 1-decene (o) , 1-octene (*) , and 1-hexene (Δ) in the LLDPE copolymer by- varying monomer feed ratios. Detailed Description of the Invention

C₁₀₊ alpha olefins which may be used in the process herein include 1-decene, 1-dodecene, 1-tetradecene, 1- hexadecene, 1-octadecene, 1-eicosene, and Cn, ₁₃, χ_{5ι 17f 19} and C₂₁-₂₄ alpha olefins, and the like. The olefins may be linear or branched. The preferred C3.0₊ α-olefin is 1-decene. C₂-₉ alpha olefins which may be used herein as including ethylene, propylene, 1-butene, 4-methyl-l-pentene, 3-methyl-l-butene, 3-methyl-l-pentene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-nonene. C₂-_S α-olefins are preferred. The preferred C₂-8 α-olefins for use herein are ethylene, propylene, 1- butene. The olefins may be linear or branched. Ethylene is most preferred.

The metallocenes of this invention may have covalently- bridged ring ligands and a ligand-metal-ligand angle, φ, formed at the metal center between the ligands of from 135° to 100°, preferably from 115° to 100°. For cyclopentadienyl and substituted cyclopentadienyl groups, the angle φ is measured from the centroid position of the five-membered ring (the point in a system of masses each of whose coordinates is a mean value of the coordinates for each dimension for all points in the system) . The angle is measured by X-ray diffraction.

The amount of the metallocene employed may be from 20 ppm weight to 1 wt.%, based upon the total amount of comonomers . The preferred amount may be from 0.001 to 0.2 wt.%, based upon the total amount of comonomers.

It is preferred that the constrained geometry metallocene be single site in order to obtain a copolymer with a desirably narrow molecular weight distribution. For LLDPE copolymers, the weight average molecular weight (M_w) is generally about twice that of the M_n and the viscosity molecular weight (M_v) is generally in between the M_w and the M_n. The M_w /M_n for the copolymers of this invention may be from 2 to 5, preferably closer to 2.

Preferred single-site constrained geometry metallocenes useful herein include metallocenes which may have the following formula:

Y-L'

(X)_n

M is a metal of Group 3 or Group 4 of the Periodic Table of the Elements. Preferred metals include titanium and zirconium. L and L' are ligands independently selected from -NR-, -PR-, cyclopentadienyl, and substituted cyclopentadienyl groups . The cyclopentadienyl and/or substituted cyclopentadienyl groups may be bound in an η⁵ bonding mode to the metal. At least one of L and L' is a cyclopentadienyl or substituted cyclopentadienyl group. Y is a bridging moiety. Y may be selected from -SiR₂-, -CR₂-, and -CR₂-CR₂-. R is independently selected from hydrogen, alkyl, aryl, silyl, halogenated alkyl, halogenated aryl and is defined in more detail below. Hydrogen is most highly preferred as Y. X is a metal substituent. X may be selected from hydrogen, halo, and alkyl, aryl, aryloxy, and alkoxy wherein the carbon atoms-containing groups may have from 1 to 20, preferably 1 to 15, more preferably 1 to 5 carbon atoms. Hydrogen is most highly preferred as X. n may be 0, 1 or 2.

More preferred single-site constrained geometry metallocenes useful herein include metallocenes which may have the following formula:

wherein M, L, I/ , Y, , X and n are defined as above. Furthermore, the L-M-I/ angle, φ, formed at the metal center between L and L' (φ= angle L-M-L') is from 135° to 100°, preferably from 115° to 100°.

R may contain from 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms, more preferably 1 to 5 carbon atoms. Specific examples of the hydrocarbon groups may include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a phenyl group, a naphthyl group, a butenyl group, a butadienyl group, a triphenylcarbyl group or the like.

The substituted cyclopentadienyl ligands may have substituent hydrocarbon groups which may be monovalent groups bonded to the cyclopentadienyl group. These substituent groups may be those R groups described in the preceding paragraph. Furthermore, the two hydrocarbon substituent groups may be bonded with each other at end positions thereof to form a condensed ring. Typical examples of cyclopentadienyl groups having the condensed ring may include indene, fluorene, azulene or derivatives thereof.

As the substituent group, R, other than the aforementioned hydrocarbon groups, there can be exemplified hydrocarbon groups containing silicon, oxygen, nitrogen, phosphorus, boron, sulfur or the like. Typical examples of the hydrocarbon residues may include a methoxy group, an ethoxy group, a phenoxy group, a furyl group, a trimethylsilyl group, a diethylamino group, a diphenylamino group, a pyrazolyl group, an indolyl group, a carbazolyl group, a dimethylphosphino group, a diphenylphosphino group, a diphenylboron group, a dimethoxyboron group, a thienyl group or the like.

Specific examples of metallocenes useful herein include

(tert-butylamido) (tetramethyl-η⁵ -cyclopentadienyl) -1,2- ethanediylzirconium dichloride, (tert-butylamido) (tetra- inethyl-η⁵-cyclopentadienyl) -1, 2-ethanediyltitanium dichloride,

(methylamido) (tetramethyl-η⁵-cyclopentadienyl) -1,2- ethanediylzirconium, dichloride, (methylamido) (tetramethyl-η⁵- cycloperitadienyl) -1, 2-ethanediyltitanium dichloride,

(ethylamido) (tetramethyl-η⁵-cyclopentadienyl) - methylenetitanium dichloro, (tert- butylamido) dibenzyl (tetramethyl-η⁵-cyclopentadienyl) silanezirconium dibenzyl, (benzylamido) dimethyl (tetramethyl- η⁵-cyclopentadienyl) silanetitanium dichloride,

(phenylphosphido) dimethyl (tetramethyl-η⁵- cyclopentadienyl) silanezirconium dibenzyl, and (tert- butylamido) dimethyl (tetramethyl-η⁵- cyclopentadienyl) silanetitanium dimethyl.

Cocatalysts useful herein include those which activate the metallocene to form an active species for alpha-olefin polymerization. Cocatalysts are sometimes referred to as activators. Specific types of cocatalyst may include alumoxanes, borates, and acidic clay and clay minerals.

Any aluminoxane suitable for use as a cocatlayst can be used herein. Mixtures of two or more aluminoxane compounds may also be used herein. Suitable aluminoxane compounds for use herein include methylalurαinoxane (MAO) and modified methylaluminoxane (MMAO) . Modified methylaluminoxane is derived from methylaluminoxane with a portion of the methyl groups replaced with other alkyl groups, for example, isobutyl groups. The alkyl groups may contain from 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms, more preferably from 1 to 5 carbon atoms. Specific examples of the hydrocarbon groups may include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a phenyl group, a naphthyl group, a butenyl group, a butadienyl group, a triphenylcarbyl group or the like. In one embodiment, the cocatalyst is a modified methylaluminoxane, preferably herein about 25% of the methyl groups are replaced with isobutyl groups .

The cocatalyst may be a borate, preferably a borate. Preferred borates include tetra (pentafluorophenyl) borate and methyltri (pentafluorophenyl) borate .

The cocatalyst may be acidic clay or a clay mineral. Preferred acidic clays include allophane group clays or clay minerals such as allophane; kaolin group clays or clay minerals such as dickite, nacrite, kaolinite or anauxite, halloysite group clays or clay minerals such as meta- halloysite or halloysite; serpentine group clays or clay minerals such as chrysotile, lizardite or antigorite; smectite group clays or clay minerals such as montmorillonite, sauconite, beidellite, nontronite, saponite or hectorite; vermiculite minerals such as vermiculite; mica minerals such as illite, sericite or glauconite; attapulgite; sepiolite; palygorskite; bentonite; gnarl clay; gairome clay hisingerite; pyrophyllite; and chlorite groups.

The catalyst may be prepared by any method known in the art. Generally, the preparation of the metallocene complex consists of forming and isolating the cyclopentadienyl or substituted cyclopentadienyl group ligands which are then reacted with a halogenated metal to form the complex. Other methods known in the art may also be employed.

Generally the process for making the copolymers of Ci₀₊ alpha olefins and other molecular size alpha olefins described herein may be carried out by any conventional means for copolymer!zation of other alpha olefins including solution, gas phase, and slurry polymerization. The polymerization may be carried out at a temperature of 25°C to 200⁰C, preferably 12O⁰C to 180°C, and a pressure of 0.5 to 6 MPa, preferably from 2 to 6 MPa. The cocatalyst may be mixed with the Cio₊ comonomer and then the ethylene (or other alpha olefin monomer) is added followed by the catalyst composition. Other methods and sequences of steps known in the art may also be utilized.

The Cio₊ alpha olefin copolymers of this invention may have a viscosity molecular weight (M_v) of from 14,000 to 500,000, preferably from 14,000 to 100,000, most preferably from 14,000 to 60,000. The amount of the C₁₀₊ alpha olefin monomer in the copolymers may range from 0.5 mol% to less than 100 mol%, preferably from 0.5 to 20, most preferably from 1.5 to 10.

The ethylene/1-decene copolymers of this invention are generally homogeneous in terms of the incorporation of the 1- decene into the copolymer. One indication of this homogeneity is shown by the narrowness of the melting point. The ethylene/1-decene copolymers of this invention are generally homogeneous in terms of the incorporation of the 1- decene into the copolymer. One indication of this homogeneity is shown by the narrowness of the melting point. Differential scanning calorimetry (DSC) was used to measure the melting temperature of the some of the copolymers with a heating rate of 10°C/min. The DSC curve was recorded in the second heating cycle. Only a single melting peak is observed throughout the composition range from 0.5 to 12 mole% 1- decene. For example, Figure 1 is the DSC melting temperature curve for the copolymer described in Table 3 below with 0.99%mol 1-decene. W is the power in watts. The melting peak completely disappears above 12 mole% of 1-decene content. The copolymer is amorphous at that point and there is only one melting point.

The half-width of the melting peak is a good way to gauge the narrowness of the melting point of the copolymers which have from 0.5 to 12 mole% 1-decene. The half-width is determined by the peak width at half of the height of the melting peak measured from top of the peak to the baseline of the whole peak. This calculation is exemplified in Figure 1 wherein the height is from the peak of 128.25°C and the low point is 121.79°C (94.14 joules per second per gram). The copolymers with 5 to 12 mole% of 1-decene content show a significant melting peak, the half-width of which may range from 5⁰C to 1O⁰C.

EXAMPLES Example 1

The experiments described herein were carried out by polymerizing 1-hexene, 1-octene, and 1-decene with ethylene under the following conditions :

Reagents: 1-hexene (comparative), 1-octene (comparative), and 1-decene were distilled over CaH₂ before being used. Heptane (anhydrous) and methylaluminoxane (MAO) cocatlayst

(10%wt in toluene) were purchased from Sigma-Aldrich and used as received. The metallocene, dimethylsilyl (t- butylamido) (tetramethylcyclopentadienyl) titanium dichloride

(CAS#: 135072-61-6) , was purchased from Boulder Scientific Company.

Polymerization: solution polymerization was carried out in an autoclave (300ml) equipped with a mechanical stirrer. In the following ethylene copolymerization reactions, the comonomer (i.e. 1-hexene, 1-octene, or 1-decene) was mixed with heptane solvent and MAO in the autoclave. The total volume of heptane and comonoraer was controlled at 100ml. The sealed reactor was then saturated with 480-500 psi (3.4-3.6 MPa) ethylene pressure at 140~15Q°C before adding the metallocene solution (i.e. in toluene) to initiate the polymerization. Additional ethylene was fed continuously into the reactor by maintaining a constant pressure during the whole course of the polymerization. After 5 minutes, the reaction was terminated by adding 100 ml. of dilute HCl solution in isopropanol. The polymer was isolated by filtering and washed completely with isopropanol and dried at 60⁰C for 20 hours.

Characterization: The composition of resulting LLDPE was measured by ¹H-NMR, ¹³C-NMR using Bruker (AVANCE300) at 110⁰C in TCB/d4-tetrachloroethane (with ratio of 2:1), and FT-IR using Varian FTS-800. In ¹H NMR spectrum, in addition to a major chemical shift between 1.45-1.35 ppm, corresponding to CH2, there is a minor chemical shift (triplet) at 1.05 ppm, corresponding to CH3 in the comonomer units. The integrated intensity ratio between two chemical shifts and the number of protons both chemical shifts represent determines the concentration of comonomer. Melting point (Tm) and heat of fusion were measured by DSC (TA DSC- QlOO) at 10°C/min in second heating cycle. The density was measured as described in ASTM D-792.

The viscosity molecular weights (M_v) of the copolymers were determined by intrinsic viscosity or/and Gel Permeation Chromatography (GPC) measurements. The intrinsic viscosity (η) is measured in a dilute decalin solution with polymer concentration of 50 mg/50ml at 135°C. The viscosity polymer molecular weight (M_v) is then calculated by equation η = k M_v ^α, in which k = 46 x 10³ and α.= 0.73. GPC measurement is carried out in a Waters 150 C with a refractive index (RI) detector and a set of u-Styragel HT columns of 10⁶, 10⁵, 10⁴, and 10³ pore size in series. The measurements were taken at 140° C using 1,2, 4-trichlorobenzene (TCB) as solvent and a mobile phase of 0.7 ml/min flow rate. Narrow molecular weight PS samples were used as standards for calibration.

The results of these experiments are shown in the following tables. Figure 2 illustrates the comparison of comonomer incorporation mole% (top) and weight% (bottom) among 1-decene (o) , 1-octene (*) , and 1-hexene (Δ) in the LLDPE copolymer by varying monomer feed ratios. Figure 2 (E means ethylene) compares the comonomer incorporation (mole% and weight%) between 1-decene and two common comonomers (1- octene and 1-hexene) in the copolymer by varying monomer feed ratios. The incorporation of 1-decene into the ethylene/1- decene copolymer is systematically higher than the incorporation of 1-hexene and 1-octene are incorporated into the ethylene/1-hexene and ethylene/1-octene copolymers.

Table 1 1-hexene as the Comonomer in Ethylene Polymerization

Table 2 1-Octene as the Comonomer in Ethylene Polymerization

Table 3 1-Decene as the Comonomer in Ethylene Polymerization

Example 2

These experiments were carried out according to the procedure of Example 1 with the exceptions that the total liquid volume was 200 ml, the ethylene pressure was 600 psi (4.1 MPa), and the reaction time was 13 minutes. Table 4 describes the copolymerization of 1-octene with ethylene and Table 5 describes the copolymerization of 1-octene with ethylene and Table 5 describes the copolymerization of 1- decene with ethylene. The copolymers from each of the three runs for each comonomer were combined and tested according to ASTM D638. The results are shown in Table 6.

Table 4

Table 5

Table 6

Claims

C L A I M S

1. A process for the copolymerization of C₁₀₊ alpha olefins with alpha olefins having a lower carbon number which comprises copolymerizing a Cχo₊ alpha olefin with an alpha olefin having a lower carbon number in the presence of a catalyst composition comprising (a) a constrained geometry metallocene and (b) a cocatalyst.

2. The process of claim 1 wherein the metallocene has substituted covalently-bridged ring ligands and the ligand- metal-ligand angle, φ, formed at the metal center between the ligands is from about 135° to about 100°.

3. The process of claim 1 wherein the metallocene is a single-site constrained geometry metallocene which has the formula:

Y-L¹

(X)_n

wherein M is a transition metal of Group 3 or Group 4 of the Periodic Table of the Elements; L and L' are ligands independently selected from -NR-, -PR-, cyclopentadienyl or substituted cyclopentadienyl groups and at least one of L and L' is a cyclopentadienyl or substituted cyclopentadienyl group; Y is a bridging moiety; each occurrence of R is independently selected from hydrogen, alkyl, aryl, silyl, halogeneated alkyl, and halogenated aryl; X is a metal substituent; and n is 0, 1 or 2.

4. The process of claim 1 wherein the metallocene is a single site constrained geometry metallocene which has the formula:

(X)_n

wherein M is a transition metal of Group 3 or Group 4 of the Periodic Table of the Elements/ L and L' are ligands independently selected from -NR-, -PR-, cyclopentadienyl or substituted cyclopentadienyl groups and at least one of L and L' is a cyclopentadienyl or substituted cyclopentadienyl group; Y is a bridging moiety; each occurrence of R is independently selected from hydrogen, alkyl, aryl, silyl, halogeneated alkyl, and halogenated aryl; X is a metal substituent; n is 0, 1 or 2; and the L-M-L' angle, φ, formed at the metal center between L and L' (φ= angle L-M-L') is from about 135° to about 100°.

5. The process of claim 4 wherein M comprises titanium or zinc.

6. The process of claim 4 wherein Y is selected from the group consisting of -SiR₂-, -CR₂-, and -CR₂-CR₂- and each occurrence of R is independently selected from the group consisting of hydrogen, alkyl, aryl, silyl, halogeneated alkyl, and halogenated aryl wherein the alkyl, aryl, halogeneated alkyl, and halogenated aryl wherein the groups containing carbon atoms have from 1 to 20 carbon atoms.

7. The process of claim 4 wherein Y is selected from the group consisting of -SiR₂-, -CR₂-, and -CR₂-CR₂- and each occurrence of R is independently selected from the group consisting of hydrocarbon groups containing silicon, oxygen, nitrogen, phosphorus, boron, sulfur or the like.

8. The process of claim 4 wherein X is selected from hydrogen, halo, alkyl, aryl, aryloxy, and alkoxy wherein the groups containing carbon atoms have from 1 to 20 carbon atoms .

9. The process of claim 4 wherein φ is from about 115° to about 100°.

10. The process of claim 1 wherein the metallocene is selected from the group consisting of (tert- butylamido) (tetramethyl-η⁵ -cyclopentadienyl) -1, 2- ethanediylzirconium dichloride, (tert-butylamido) (tetra- methyl-η⁵-cyclopentadienyl) -1, 2-ethanediyltitanium dichloride, (methylamido) (tetramethyl-η⁵-cyclopentadienyl) -1,2- ethanediylzirconium dichloride, (methylamido) (tetramethyl-η⁵- cycloperitadienyl) -1, 2-ethanediyltitanium dichloride,

(ethylamido) (tetramethyl-η⁵-cyclopentadienyl) - rαethylenetitanium dichloro, (tert- butylamido) dibenzyl (tetramethyl-η⁵-cyclopentadienyl) silanezirconium dibenzyl, benzylamido) dimethyl (tetramethyl- η⁵-cyclopentadienyl) silanetitanium dichloride, phenylphosphido) dimethyl (tetramethyl-η⁵- cyclopentadienyl) silanezirconium dibenzyl, and (tert- butylamido) dimethyl (tetramethyl-η⁵- cyclopentadienyl) silanetitanium dimethyl.

11. The process of claim 1 wherein the cocatalyst is selected from the group consisting of alumoxanes, borates, and acidic clay.

12. The process of claim 11 wherein the cocatalyst is an alumoxane selected from the group consisting of methylaluminoxane (MAO) and modified methylaluminoxane

(MMAO) .

13. The process of claim 11 wherein the cocatalyst is a borate selected from the group consisting of tetra (pentafluorophenyl ) borate and rαethyltri (pentafluorophenyl) borate .

14. The process of claim 11 wherein the cocatalyst is selected from the group consisting of allophane group clays, allophone, kaolin group clays, dickite, nacrite, kaolinite, anauxite, halloysite group clays, meta-halloysite, halloysite, serpentine group clays, chrysotile, lizardite, antigorite, smectite group clays, montmorillonite, sauconite, beidellite, nontronite, saponite, hectorite, vermiculite minerals including vermiculite, mica minerals including illite, sericite, and glauconite, attapulgite, sepiolite, palygorskite, bentonite, gnarl clay, gairome clay hisingerite, pyrophyllite, and chlorite groups.

15. The process of claim 1 wherein the alpha olefin having a lower carbon number is a C₂-₉ alpha olefin.

16. The process of claim 15 wherein the alpha olefin having a lower carbon number is a C₂-₈ alpha olefin.

17. The process of claim 16 wherein the C2-8 alpha olefin is selected from the group consisting of ethylene, propylene, and 1-butene.

18. The process of claim 17 wherein the C₂-8 alpha olefin comprises ethylene.

19. The process of claim 1 wherein the Ci₀₊ alpha olefin is selected from the group consisting of 1-decene and Cn-₂₄ alpha olefins.

20. The process of claim 19 wherein the Ci₀₊ alpha olefin comprises 1-decene.

21. The process of claim 1 wherein the temperature is from about 25°C to about 200°C and the pressure is from about 0.5 to about 6 MPa.

22. The process of claim 1 wherein the constrained geometry metallocene is a single-site constrained geometry metallocene .

23. A copolymer of ethylene and 1-decene which comprises from about 0.5 to less than 100 % mol 1-decene.

24. The copolymer of claim 23 wherein the amount of 1-decene is from about 0.5 to about 20 mol %.

25. The copolymer of claim 24 wherein the amount of 1-decene is from about 1.5 to about 10 mol%.

26. A copolymer of ethylene and 1-decene having a viscosity molecular weight of from about 14,000 to about 500,000.

27. The copolymer of claim 26 wherein the viscosity molecular weight is from about 14,000 to about 100,000.

28. The copolymer of claim 27 wherein the viscosity molecular weight is from about 14,000 to about 60,000.

29. A copolymer of ethylene and 1-decene wherein the half- width of the DSC melting temperature peak measured at 1O⁰C per minute in the second heating cycle is from about 5°C to about 10⁰C.