ETHYLENE COPOLYMERS WITH IMPROVED MELTING AND GLASS TRANSITION TEMPERATURE

Abstract

The present inventions concerns a copolymer of ethylene and an C3 to C8 alpha-olefin, wherein the copolymer has a density of 890 to 915 kg/m.sup.3 measured according to ISO 1183 and a MFR2 of 0.5 to 8.0 g/10 min measured according to ISO 1133, wherein the alpha-olefin is present in the copolymer in an amount of 10 to 20 wt. %, wherein the copolymer has a melt point T.sub.m between 100 and 120° C. measured according to ISO 11357-3 and a Vicat softening temperature T.sub.vicat of 80 to 96° C.

Claims

1. Copolymer of ethylene and an C3 to C8 alpha-olefin, wherein the copolymer has a density of 890 to 915 kg/m.sup.3 measured according to ISO 1183 and a MFR.sub.2 of 0.5 to 8.0 g/10 min measured according to ISO 1133, wherein the alpha-olefin is present in the copolymer in an amount of 10 to 20 wt. %, wherein the copolymer has a melting temperature T.sub.m between 100 and 120° C. measured according to ISO 11357-3 and a Vicat softening temperature T.sub.Vicat of 80 to 96° C. measured according to ISO 306.

2. The copolymer according to claim 1, wherein the copolymer is a copolymer of ethylene and octene.

3. The copolymer according to claim 1, wherein the copolymer has an MFR.sub.2 of 0.6 to 4.0 g/10 min measured according to ISO 1133.

4. The copolymer according to claim 1, wherein the copolymer has an MFR.sub.21 of 30 to 45 g/10 min measured according to ISO 1133.

5. The copolymer according to claim 1, wherein the copolymer has a ratio MFR.sub.21/MFR.sub.2 of 30 to 45 measured according to ISO 1133.

6. The copolymer according to claim 1, wherein the copolymer has an Mw/Mn of 2.5 to 3.0 determined by Gel Permeation Chromatography.

7. The copolymer according to claim 1, wherein the copolymer has an Mw of 75000 to 90000 g/mol determined by Gel Permeation Chromatography.

8. The copolymer according to claim 1, wherein the copolymer has a crystallisation temperature T.sub.c of 82 to 96° C. measured according to ISO 11357-3.

9. The copolymer according claim 1, wherein the copolymer has a glass transition temperature T.sub.g of −35 to −45° C. measured according to ISO 6721-7.

10. The copolymer according to claim 1, wherein the copolymer has a vinyl content of 4.0 to 8.0 vinyl groups per 100000 carbon atoms measured with .sup.1H NMR.

11. The copolymer according to claim 1, wherein the copolymer has a vinylidene content of 9.0 to 14 vinylidene groups per 100000 carbon atoms measured with .sup.1H NMR.

12. The copolymer according to claim 1, wherein the copolymer has a trisubstituted vinylene content of 15.0 to 24.0 trisubstituted vinylene groups per 100000 carbon atoms measured with .sup.1H NMR.

13. The copolymer according to claim 1, wherein the copolymer has a vinylene content of 10.0 to 16.0 vinylene groups per 100000 carbon atoms measured with .sup.1H NMR.

14. The copolymer according to claim 1, wherein the copolymer is obtained by blending a first ethylene copolymer and a second ethylene copolymer, wherein the first ethylene copolymer has a higher density than the second ethylene copolymer.

15. The copolymer according to claim 14, wherein a blending ratio of the first ethylene copolymer to the second ethylene copolymer is from 65:35 to 85:15 wt. %.

Description

EXAMPLE SECTION

1. Measurement Methods

a) Melt Flow Rate (MFR) and Flow Rate Ratio (FRR)

[0111] The melt flow rate (MFR) is determined according to ISO 1133—Determination of the melt mass-flow rate (MFR) and melt volume-flow rate (MVR) of thermoplastics—Part 1: Standard method, and is indicated in g/10 min. The MFR is an indication of flowability, and hence processability, of the polymer. The higher the melt flow rate, the lower the viscosity of the polymer.

[0112] The MFR.sub.2 of polypropylene is determined at a temperature of 230° C. and a load of 2.16 kg.

[0113] The MFR.sub.2 of polyethylene is determined at a temperature of 190° C. and a load of 2.16 kg.

[0114] The flow rate ratio (FRR) is the MFR.sub.21/MFR.sub.2.

b) Density

[0115] The density of the (co-)polymer was measured according to ISO 1183.

c) Comonomer Content

[0116] Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used to quantify the comonomer content of the polymers.

[0117] Quantitative .sup.13C{.sup.1H} NMR spectra recorded in the molten-state using a Bruker Avance III 500 NMR spectrometer operating at 500.13 and 125.76 MHz for .sup.1H and .sup.13C respectively. All spectra were recorded using a .sup.13C optimised 7 mm magic-angle spinning (MAS) probehead at 150° C. using nitrogen gas for all pneumatics. Approximately 200 mg of material was packed into a 7 mm outer diameter zirconia MAS rotor and spun at 4 kHz. This setup was chosen primarily for the high sensitivity needed for rapid identification and accurate quantification. Standard single-pulse excitation was employed utilising the transient NOE at short recycle delays of 3 s and the RS-HEPT decoupling scheme. A total of 1024 (1 k) transients were acquired per spectrum.

[0118] Quantitative .sup.13C{.sup.1H} NMR spectra were processed, integrated and quantitative properties determined using custom spectral analysis automation programs. All chemical shifts are internally referenced to the bulk methylene signal (d+) at 30.00 ppm.

[0119] Characteristic signals corresponding to the incorporation of 1-octene were observed and all comonomer contents calculated with respect to all other monomers present in the polymer.

[0120] Characteristic signals resulting from isolated 1-octene incorporation i.e. EEOEE comonomer sequences, were observed. Isolated 1-octene incorporation was quantified using the integral of the signal at 38.3 ppm. This integral is assigned to the unresolved signals corresponding to both *B6 and .sub.*bB6B6 sites of isolated (EEOEE) and isolated double non-consecutive (EEOEOEE) 1-octene sequences respectively. To compensate for the influence of the two .sub.*bB6B6 sites the integral of the bbB6B6 site at 24.6 ppm is used:

I=I.sub.*B6+*bB6B6−2*I.sub.bbB6B6

[0121] Characteristic signals resulting from consecutive 1-octene incorporation, i.e. EEOOEE comonomer sequences, were also observed. Such consecutive 1-octene incorporation was quantified using the integral of the signal at 40.4 ppm assigned to the aaB6B6 sites accounting for the number of reporting sites per comonomer:

OO=2*I.sub.aaB6B6

[0122] Characteristic signals resulting from isolated non-consecutive 1-octene incorporation, i.e. EEOEOEE comonomer sequences, were also observed. Such isolated non-consecutive 1-octene incorporation was quantified using the integral of the signal at 24.6 ppm assigned to the bbB6B6 sites accounting for the number of reporting sites per comonomer:

OEO=2*I.sub.bbB6B6

[0123] Characteristic signals resulting from isolated triple-consecutive 1-octene incorporation, i.e. EEOOOEE comonomer sequences, were also observed. Such isolated triple-consecutive 1-octene incorporation was quantified using the integral of the signal at 41.2 ppm assigned to the aagB6B6B6 sites accounting for the number of reporting sites per comonomer:

OOO=3/2*I.sub.aagB6B6B6

[0124] With no other signals indicative of other comonomer sequences observed the total 1-octene comonomer content was calculated based solely on the amount of isolated (EEOEE), isolated double-consecutive (EEOOEE), isolated non-consecutive (EEOEOEE) and isolated triple-consecutive (EEOOOEE) 1-octene comonomer sequences:

O.sub.total=O+OO+OEO+OOO

[0125] Characteristic signals resulting from saturated end-groups were observed. Such saturated end-groups were quantified using the average integral of the two resolved signals at 22.9 and 32.23 ppm. The 22.84 ppm integral is assigned to the unresolved signals corresponding to both 2B6 and 2S sites of 1-octene and the saturated chain end respectively. The 32.2 ppm integral is assigned to the unresolved signals corresponding to both 3B6 and 3S sites of 1-octene and the saturated chain end respectively. To compensate for the influence of the 2B6 and 3B6 1-octene sites the total 1-octene content is used:

S=(½)*(I.sub.2S+2B6+I.sub.3S+3B6−2*O.sub.total)

[0126] The ethylene comonomer content was quantified using the integral of the bulk methylene (bulk) signals at 30.00 ppm. This integral included the D and 4B6 sites from 1-octene as well as the D.sup.D sites. The total ethylene comonomer content was calculated based on the bulk integral and compensating for the observed 1-octene sequences and end-groups:

Etotal=(½)*[I.sub.bulk+2*O+1*OO+3*OEO+0*OOO+3*S]

[0127] It should be noted that compensation of the bulk integral for the presence of isolated triple-incorporation (EEOOOEE) 1-octene sequences is not required as the number of under and over accounted ethylene units is equal.

[0128] The total mole fraction of 1-octene in the polymer was then calculated as:

fO=O.sub.total/(E.sub.total+O.sub.total)

[0129] The total comonomer incorporation of 1-octene in weight percent was calculated from the mole fraction in the standard manner:

O[wt %]=100*(fO*112.21)/((fO*112.21)+((1−fO)*28.05))

[0130] Further information can be found in the following references: [0131] Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207:382. [0132] Parkinson, M., Klimke, K., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2007; 208:2128. [0133] NMR Spectroscopy of Polymers: Innovative Strategies for Complex Macromolecules, Chapter 24, 401 (2011) [0134] Pollard, M., Klimke, K., Graf, R., Spiess, H. W., Wilhelm, M., Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004; 37:813. [0135] Filip, X., Tripon, C., Filip, C., J. Mag. Resn. 2005, 176, 239 [0136] Griffin, J. M., Tripon, C., Samoson, A., Filip, C., and Brown, S. P., Mag. Res. in Chem. 2007 45, S1, S198 [0137] Castignolles, P., Graf, R., Parkinson, M., Wilhelm, M., Gaborieau, M., Polymer 50 (2009) 2373 [0138] Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225 [0139] Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128 [0140] J. Randall, Macromol. Sci., Rev. Macromol. Chem. Phys. 1989, C29, 201. [0141] Qiu, X., Redwine, D., Gobbi, G., Nuamthanom, A., Rinaldi, P Macromolecules 2007, 40, 6879 [0142] Liu, W., Rinaldi, P., McIntosh, L., Quirk, P., Macromolecules 2001, 34, 4757

d) Unsaturation

[0143] Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used to quantify the content of unsaturated groups present in the polymers.

[0144] Quantitative .sup.1H NMR spectra recorded in the solution-state using a Bruker Avance III 400 NMR spectrometer operating at 400.15 MHz. All spectra were recorded using a .sup.13C optimised 10 mm selective excitation probehead at 125° C. using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 1,2-tetrachloroethane-d.sub.2 (TCE-d.sub.2) using approximately 3 mg of Hostanox 03 (CAS 32509-66-3) as stabiliser. Standard single-pulse excitation was employed utilising a 30 degree pulse, a relaxation delay of 10 s and 10 Hz sample rotation. A total of 128 transients were acquired per spectra using 4 dummy scans. This setup was chosen primarily for the high resolution needed for unsaturation quantification and stability of the vinylidene groups. All chemical shifts were indirectly referenced to TMS at 0.00 ppm using the signal resulting from the residual protonated solvent at 5.95 ppm.

[0145] Characteristic signals corresponding to the presence of terminal aliphatic vinyl groups (R—CH═CH.sub.2) were observed and the amount quantified using the integral of the two coupled inequivalent terminal CH.sub.2 protons (Va and Vb) at 4.95, 4.98 and 5.00 and 5.05 ppm accounting for the number of reporting sites per functional group:

Nvinyl=IVab/2

[0146] When characteristic signals corresponding to the presence of internal vinylidene groups (RR′C═CH2) were observed the amount is quantified using the integral of the two CH2 protons (D) at 4.74 ppm accounting for the number of reporting sites per functional group:

Nvinylidene=ID/2

[0147] When characteristic signals corresponding to the presence of internal cis-vinylene groups (E-RCH═CHR′), or related structure, were observed the amount is quantified using the integral of the two CH protons (C) at 5.39 ppm accounting for the number of reporting sites per functional group:

Ncis=IC/2

[0148] When characteristic signals corresponding to the presence of internal trans-vinylene groups (Z—RCH═CHR′) were observed the amount is quantified using the integral of the two CH protons (T) at 5.45 ppm accounting for the number of reporting sites per functional group:

Ntrans=IT/2

[0149] When characteristic signals corresponding to the presence of internal trisubstituted-vinylene groups (RCH═CHR′R″), or related structure, were observed the amount is quantified using the integral of the CH proton (Tris) at 5.14 ppm accounting for the number of reporting sites per functional group:

Ntris=ITris

[0150] The Hostanox 03 stabiliser was quantified using the integral of multiplet from the aromatic protons (A) at 6.92, 6.91, 6.69 and at 6.89 ppm and accounting for the number of reporting sites per molecule:

H=IA/4

[0151] As is typical for unsaturation quantification in polyolefins the amount of unsaturation was determined with respect to total carbon atoms, even though quantified by .sup.1H NMR spectroscopy. This allows direct comparison to other microstructure quantities derived directly from 130 NMR spectroscopy.

[0152] The total amount of carbon atoms was calculated from integral of the bulk aliphatic signal between 2.85 and −1.00 ppm with compensation for the methyl signals from the stabiliser and carbon atoms relating to unsaturated functionality not included by this region:

NCtotal=(Ibulk−42*H)/2+2*Nvinyl+2*Nvinylidene+2*Ncis+2*Ntrans+2*Ntris

[0153] The content of unsaturated groups (U) was calculated as the number of unsaturated groups in the polymer per thousand total carbons (kCHn):

U=1000*N/NCtotal

[0154] The total amount of unsaturated group was calculated as the sum of the individual observed unsaturated groups and thus also reported with respect per thousand total carbons:

Utotal=Uvinyl+Uvinylidene+Ucis+Utrans+Utris

[0155] The relative content of a specific unsaturated group (U) is reported as the fraction or percentage of a given unsaturated group with respect to the total amount of unsaturated groups:

[U]=Ux/Utotal

[0156] Further information can be found in the following references: [0157] He, Y., Qiu, X, and Zhou, Z., Mag. Res. Chem. 2010, 48, 537-542. [0158] Busico, V. et. al. Macromolecules, 2005, 38 (16), 6988-6996

e) Determination of the Molecular Weight Averages, Molecular Weight Distribution

[0159] Molecular weight averages (Mz, Mw and Mn), Molecular weight distribution (MWD) and its broadness, described by polydispersity index, PDI=Mw/Mn (wherein Mn is the number average molecular weight and Mw is the weight average molecular weight) were determined by Gel Permeation Chromatography (GPC) according to ISO 16014-1:2003, ISO 16014-2:2003, ISO 16014-4:2003 and ASTM D 6474-12 using the following formulas:

[00001]$\begin{array}{cc}{M}_n=\frac{{.Math.}_{i=1}^N{A}_i}{{.Math.}_{i=1}^N\left(A_i/M_i\right)}& \left(1\right)\end{array}$$\begin{array}{cc}{M}_w=\frac{{.Math.}_{i=1}^N\left(A_i\times M_i\right)}{{.Math.}_{i=1}^N{A}_i}& \left(2\right)\end{array}$$\begin{array}{cc}{M}_z=\frac{{.Math.}_{i=1}^N\left(A_i\times M_i^2\right)}{{.Math.}_{i=1}^N\left(A_i/M_i\right)}& \left(3\right)\end{array}$

[0160] For a constant elution volume interval ΔV.sub.i, where A.sub.i, and M.sub.i are the chromatographic peak slice area and polyolefin molecular weight (MW), respectively associated with the elution volume, V.sub.i, where N is equal to the number of data points obtained from the chromatogram between the integration limits.

[0161] A high temperature GPC instrument, equipped with a multiple band infrared detector model IR5 (PolymerChar, Valencia, Spain), equipped with 3× Agilent-PLgel Olexis and 1× Agilent-PLgel Olexis Guard columns was used. As the solvent and mobile phase 1,2,4-trichlorobenzene (TCB) stabilized with 250 mg/L 2,6-Di tert butyl-4-methyl-phenol) was used. The chromatographic system was operated at 160° C. at a constant flow rate of 1 mL/min. 200 μL of sample solution was injected per analysis. Data collection was performed by using PolymerChar GPC-one software.

[0162] The column set was calibrated using universal calibration (according to ISO 16014-2:2003) with 19 narrow MWD polystyrene (PS) standards in the range of 0.5 kg/mol to 11 500 kg/mol. The PS standards were dissolved at room temperature over several hours. The conversion of the polystyrene peak molecular weight to polyolefin molecular weights is accomplished by using the Mark Houwink equation and the following Mark Houwink constants:

K.sub.PS=19×10.sup.−3 mL/g, α.sub.PS=0.655

K.sub.PE=39×10.sup.−3 mL/g, α.sub.PE=0.725

[0163] A third order polynomial fit was used to fit the calibration data.

[0164] All samples were prepared in the concentration range of 0.5 to 1 mg/ml and dissolved at 160° C. for 3 hours under continuous gentle shaking.

f) Melting Temperature (T.sub.m) and Crystallization Temperature (T.sub.c)

[0165] Experiments were performed with a TA Instruments Q200, calibrated with Indium, Zinc, Tin and according to ISO 11357-3. Roughly 5 mg of material were placed in a pan and tested at 10° C./min throughout the experiments, under 50 mL/min nitrogen flow, with lower and higher temperatures of −30° C. and 180° C. respectively. Only the second heating run was considered for the analysis. The melting temperature T.sub.m is defined as the temperature of the main peak of the thermogram, while the melting enthalpy (ΔHm) is calculated by integrating between 10° C. and the end of the thermogram, typically T.sub.m+15° C. The running integral in this range is also calculated.

g) Glass Transition Temperature (T.SUB.g.)

[0166] The glass transition temperature Tg is determined by dynamic mechanical analysis according to ISO 6721-7. The measurements are done in torsion mode on compression moulded samples (40×10×1 mm3) between −100° C. and +150° C. with a heating rate of 2° C./min and a frequency of 1 Hz.

h) Vicat Temperature (T.SUB.Vicat.)

[0167] The Vicat temperature is measured according to ISO 306, method A50. A flat-ended needle loaded with a mass of 10 N is placed in direct contact with an injection moulded test specimen with the dimensions of 80×10×4 mm3 as described in EN ISO 1873-2. The specimen and the needle are heated at 50° C./h. The temperature at which the needle has penetrated to a depth of 1 mm is recorded as the Vicat softening temperature.

2. Materials

[0168] a) Comparative Example 1 (CE1) [0169] CE1 is an ethylene based octene-1 plastomer (octene content 15.7 wt. %) having an MFR.sub.2 of 1.1 g/10 min, a density of 902 kg/m.sup.3 and a melting temperature T.sub.m of 97° C., commercially available from Borealis. CE1 was produced in a solution polymerisation process using a metallocene catalyst. [0170] b) Copolymer A is an ethylene based octene-1 plastomer (octene content 11.9 wt. %) having an MFR.sub.2 of 1.1 g/10 min, a density of 910 kg/m.sup.3 and a melting temperature T.sub.m of 106° C. [0171] c) Copolymer B is an ethylene based octene-1 plastomer (octene content 25.8 wt. %) having an MFR.sub.2 of 1.1 g/10 min, a density of 882.3 kg/m.sup.3 and a melting temperature T.sub.m of 73° C. [0172] d) Copolymer C is an ethylene based octene-1 elastomer (octene content 37.1 wt. %) having an MFR.sub.2 of 1.0 g/10 min, a density of 862 kg/m.sup.3 and a melting temperature T.sub.m of 35° C. [0173] e) Copolymer D is an ethylene based octene-1 elastomer (octene content 31.5 wt. %) having an MFR.sub.2 of 1.0 g/10 min, a density of 870 kg/m.sup.3 and a melting temperature T.sub.m of 56° C.

[0174] Copolymers A to D were produced with Borealis proprietor Borceed™ solution polymerization technology, in the present of metallocene catalyst (phenyl)(cyclohexyl) methylene (cyclopentadienyl) (2,7-di-tert-butylfluorenyl) hafnium dimethyl and N,N-Dimethylanilinium Tetrakis(pentafluorophenyl)borate (AB) (CAS 118612-00-3) was used, commercially available from Boulder, as cocatalyst.

[0175] The polymerization conditions, were selected in such a way that the reacting system is one liquid phase (T between 150 and 200° C., 60 to 150 bar).

3. Results

[0176] Blending of the respective material was done using Prism TSE-16, a 16 mm co-rotating twin screw extruder with L/D 25, with throughput of approximately 1.4 kg/h. Temperature profile was set to 180-200° C. and the machine was operated at 250 rpm. Samples were produced by mixing a dry blend of base resin pellets and extruding said mixture. Around 2.5 kg of dry blend was fed to hopper for the batch and after stabilisation around 2.0 kg of the final extruded blend was collected.

[0177] The inventive examples IE1-1 to IE1-3 are blends of two copolymers in specific blend ratios. Results are provided in Table 1 below.

TABLE-US-00001 TABLE 1 Results CE1 IE1-1 IE1-2 IE1-3 Blend ratio — 83 wt. % 80 wt. % 71 wt. % Copo. A Copo. A Copo. A 17 wt. % 20 wt. % 29 wt. % Copo. C Copo. D Copo. B C8 content, 15.7 14.9 15.2 15.3 wt. % Density, 902 902 903.1 902.1 kg/m.sup.3 M.sub.w, g/mol 81650 81350 82800 82250 M.sub.w/M.sub.n 2.6 2.72 2.64 2.72 MFR.sub.2, g/10 min 1.1 1.02 0.99 1.03 MFR.sub.21, g/10 min 31.54 37.05 37.53 36.3 MFR.sub.21/MFR.sub.2 30.62 36.32 37.91 35.24 T.sub.m, ° C. 97 102.63 103.7 102.01 T.sub.c, ° C. 78.42 89.9 T.sub.g, ° C. −35.48 −41.55 −41.55 T.sub.Vicat, ° C. 82 87.2 Vinylidene, 12.3 11.5 12.1 12.1 100 kCHn Vinyl, 5.6 5.0 6.9 5.8 100 kCHn Trisubst, 19.2 17.7 17.40 21.2 100 kCHn Vinylene, 8.8 12.7 14.40 14.0 100 kCHn

[0178] The above results show that blending two different copolymers targeting an existing product (CE1) leads to copolymers (IE1-1 to IE1-3) with significantly better melting temperature T.sub.m as well as improved T.sub.g, improved T.sub.c and improved T.sub.Vicat at comparable density, melt flow rate, M.sub.w and octene comonomer content.