RUBBER COMPOSITION

Abstract

A rubber composition, comprising i) an ethylene--olefin-non-conjugated-diene copolymer havinga Mooney viscosity ML (1+8) at 150 C. 85 MU andan ethylene content63 wt. %the diene content is 4 to 8% by weight of the ethylene-a-olefin-non-conjugated-diene copolymer i), the non-conjugated diene is a combination of 5-ethylidene-2-norbornene (ENB) and 5-vinylnorbornene (VNB), the ethylene--olefin-non-conjugated-diene copolymer i) has an amount of VNB between 0.05 and 1 wt. %, and has a Mw of at least 400,000 g/mol and, ii) an extender oil of 10 to 40 phr based on the copolymer i) with the sum of the EPDM copolymer i) and the oil ii) amounting to at least 95 wt. % of the composition.

Claims

1. A rubber composition comprising: i) an ethylene--olefin-non-conjugated-diene copolymer having: a Mooney viscosity ML (1+8) at 150 C.85 MU; an ethylene content63 wt. %; a diene content of 4 to 8 % by weight wherein the non-conjugated diene is a combination of 5-ethylidene-2-norbornene (ENB) and 5-vinylnorbornene (VNB); an amount of VNB of 0.05 to 1 wt. %; and a Mw of at least 400,000 g/mol; and ii) 10 to 40 phr of an extender oil, based on the copolymer i); wherein a sum of the copolymer i) and the oil ii) is at least 95 wt. % of the composition.

2. The rubber composition according to claim 1, wherein the Mooney viscosity ML (1+8) at 150 C. is 85 to 150 MU.

3. The rubber composition according to claim 1, wherein the ethylene content is 55to 63 wt. %.

4. The rubber composition according to claim 1, wherein the ethylene content is 60 wt. %.

5. The rubber composition according to claim 1, wherein the ethylene content is 55to 60 wt. %.

6. The rubber composition according to claim 1 wherein the ethylene--olefin-non-conjugated-diene copolymer i) has a molecular weight distribution (MWD=Mw/Mn) of 3.5 to 6.0.

7. The rubber composition according to claim 1 wherein the ethylene--olefin-non-conjugated-diene copolymer i) has a of 0 to 30.

8. The rubber composition according to claim 1 wherein the diene content is 4 to 6% by weight of the ethylene--olefin-non-conjugated-diene copolymer i).

9. The rubber composition according to claim 1 wherein the amount of VNB is 0.1 to 0.75 wt. %.

10. The rubber composition according to claim 1, wherein the -olefin of the ethylene--olefin-non-conjugated-diene copolymer i) is selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octane and 1-decene.

11. The rubber composition according to claim 1, wherein the extender oil ii) is selected from the group consisting of paraffinic, naphthenic and aromatic extender oils obtained by purifying high boiling fractions of petroleum.

12. A process for forming a vulcanized rubber article, the process comprising: mixing: a) the rubber composition according to claim 1, b) a vulcanization package, c) one or more filler(s), d) one or more plasticizer(s), and e) optionally, other rubber additives to form a vulcanizable rubber mixture, wherein the mixture has a total compound loading of at least 250 phr, in particular at least 350 phr, preferably at least 450 phr and even more preferably of at least 550 phr, and processing the mixture to form a shaped, moulded article; and vulcanizing the shaped article.

13. The rubber composition according to claim 1, wherein: the Mooney viscosity ML (1+8) at 150 C. is 85 to 150 MU; the ethylene content is 55 to 60 wt. %; the ethylene--olefin-non-conjugated-diene copolymer i) has a molecular weight distribution (MWD=Mw/Mn) of 3.5 to 6.0; the ethylene--olefin-non-conjugated-diene copolymer i) has a of 0 to 30; the diene content is 4 to 6% by weight; and the amount of VNB is 0.1 to 0.75 wt. %.

14. The rubber composition according to claim 13, wherein: the is 6 to 20; the ethylene, non-conjugated diene, and -olefin comprise greater than 99 wt. % of the monomers of the ethylene--olefin-non-conjugated-diene copolymer; the -olefin is selected from the group consisting of propylene, 1-butene, 1 pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene; and the extender oil ii) is selected from the group consisting of paraffinic, naphthenic, and aromatic extender oils obtained by purifying high boiling fractions of petroleum.

15. The rubber composition according to claim 14, wherein: the is 5 to 15; the -olefin is at least one of propylene and 1-butene; the ethylene, non-conjugated diene, and -olefin comprise 100 wt. % of the monomers of the ethylene--olefin-non-conjugated-diene copolymer; the extender oil ii) is paraffinic oil; the Mw is 400,000 g/mol to 700,000 g/mol; and the sum of the copolymer i) and the oil ii) is at least 98 wt. % of the composition.

Description

EXAMPLES

Preparation of EPDM Copolymers Examples 1 and 2.

[0071] The polymerization was carried out in a solution polymerization reactor with a volume of 3 L. The hexanes, ethylene, propylene, dienes and hydrogen feed streams were purified by contacting with various absorption media to remove catalyst-killing impurities, such as water, oxygen and polar compounds, as is known to those skilled in the art. The process is continuous in all feed streams. Pre-mixed hexanes, propylene, ethylene, dienes, hydrogen, tri-octyl aluminium and butylated hydroxytoluene were pre-cooled before being fed to the reactor. A solution, containing the catalyst compound 19 as disclosed in WO2005/090418 and triphenylcarbenium tetrakisperfluorophenylborate, was fed separately to the reactor. The hydrogen content was adjusted to achieve the desired polymer Mooney as given in Table 2. The polymer solution was continuously removed through a discharge line, where a solution of Irganox 1076 in iso-propanol was added, optionally a paraffinic extender oil was added to the polymer solution, and, finally, the solution of polymer (and oil) is worked up by continuously steam stripping. The final EPDM sample was obtained after batch-wise drying of the polymer on a 2-roll mill.

[0072] The EPDM polymers examples 1 and 2 were analyzed using FT-IR for chemical composition, according to ASTM D 3900 and D 6047, oil content via extraction with acetone, Mooney viscosity ML(1+8) @ 150 C. according to ISO 289, the degree of branching as indicated by the parameter as explained in H. C. Booij, Kautsch. Gummi Kunstst. 44 (1991) 128 and GPC for the molecular weights Mw and Mn and molecular weight distribution MWD. Table 2 compares the polymer characteristics of EPDM examples 1 and 2 with those of the commercial references KEP2371 and K8550C. The propylene wt. % content is not given in Table 2, but can be calculated for the given grades to be 100% minus the sum of ethylene, ENB and VNB contents. For the commercial grades in Table 2 the ethylene and ENB data are taken from the brochures and the VNB content was measured according to ASTM D 6047.

[0073] Table 2 compares the polymer characteristics of EPDM examples 1 and 2 with those of the commercial grades KEP2371 and K8550C.

TABLE-US-00002 TABLE 2 EPDM compositions EPDM K8550C KEP2371 example 1 example 2 ethylene (wt. %) 48 .sup.1) 70 .sup.2) 56.5 60.4 ENB (wt. %) 5.5 .sup.1) 7 .sup.2) 4.9 4.8 VNB (wt. %) 0.26 0.0 0.23 0.22 oil (phr) 0 .sup.1) 0 .sup.2) 0 12.6 ML (1 + 8) (MU) 52.4 88.2 86.7 104 .sup.3) @ 150 C. () 18.2 14 11.0 14.8 Mn kg/mol 89 89 95 139 Mw kg/mol 310 370 390 510 Mw/Mn 3.5 4.2 4.1 3.7 .sup.1) data from Arlanxeo Performance Elastomers: see http://keltan.com/en/the-power-of-keltan/premium-quality/brochures/ .sup.2) Kumho Polychem; see http://www.kumhopolychem.co.kr/eng/product/epdm?seq = 1 .sup.3) ML (1 + 8) @ 150 C. of product composed of EPDM with ML (1 + 8) @ 150 of 104 and 12.6 phr of oil isC 87.8 MU

TABLE-US-00003 TABLE 1a Overview of various commercial EPDM products and inventive grades Mooney viscosity chemical composition brochure data calculated .sup.6) brochure data ML (1 + 4) ML (1 + 8) ML (1 + 4) ML (1 + 8) ML (1 + 8) @ 150 ethylene ENB oil @ 125 C. @ 125 C. @ 150 C. @ 150 C. C. polymer content content content EPDM product (MU) (MU) (MU) (MU) (MU) (wt. %) (wt. %) (phr) Esprene 5277F .sup.1) 81 74 54 8.5 Royalene 515 .sup.2) 82 75 56 9.5 KEP2371 .sup.3) 115 88 70 7.0 Keltan 8550C .sup.4) 80 52 48 5.5 Keltan 9950C .sup.4) 60 60 44 9.0 Keltan 3973 .sup.4) 34 52 66 9.0 30 Keltan 9565Q .sup.4) 67 124 62 5.5 50 Keltan 5469 .sup.4) 52 144 63 4.5 100 example 1 .sup.5) 88 88 58 5.0 example 2 .sup.5) 88 105 56 5.5 15 .sup.1) Sumitomo Chemical; see http://www.sumitomo-chem.co.jp/polyolefin/03product/pdf/22esprene_epdm.pdf .sup.2) Lion Elastomers; see http://lionelastomers.com/main/royalene_royaledge .sup.3) Kumho Polychem; see http://www.kumhopolychem.co.kr/eng/product/epdm?seq=1 .sup.4) Arlanxeo; see http://keltan.com/en/the-power-of-keltan/premium-quality/brochures/ .sup.5) this invention .sup.6) to allow a comparison, the Mooney data to the extent data at 150 C. were not available or not measured have been converted to ML (1 + 8) @ 150 C. by using correlations based on experimental data for ML (1 + 4) @ 125 C., ML (1 + 8) @ 125 C., ML (1 + 4) @ 150 C. and ML (1 + 8) @ 150 C. for a variety of EPDM polymers; a correction for the presence of oil was made for ML (1 + 4) @ 125 C. with 1.5 MU/phr oil which was based on ML (1 + 4) @ 125 C. data for oil-extended EPDM polymers before and after acetone extraction of the oil.

Preparation of a Vulcanizable Rubber Composition

[0074] Ingredients:

[0075] Various vulcanizable rubber compositions based on four different EPDM products without or with 15 phr extender oil (cf. Table 2) and in roughly 400, 500 and 600 phr compounds were prepared (Table 3). The ingredients used for the various compound evaluations are listed in Table 4.

TABLE-US-00004 TABLE 3 EPDM compund compositions used for evaluation different EPDM products without oil or with 15 phr of oil in 400, 500 and 600 phr compounds. composition based on A), B) or C) composition based on D) ingredient 400 phr 500 phr 600 phr 400 phr 500 phr 600 phr non-oil EPDM A), B) or C) 100 100 100 0 0 0 EPDM D) 0 0 0 115 115 115 Corax N-550 120 160 200 120 160 200 Whiting BSH 80 100 120 80 100 120 Sunpar 2280 80 115 150 65 100 135 ZnO aktiv 5 5 5 5 5 5 Edenor C 18 98-100 1 1 1 1 1 1 PEG (4000) 2 2 2 2 2 2 milled sulfur 90/95 0.3 0.3 0.3 0.3 0.3 0.3 Rhenogran CaO-80 6.9 6.9 6.9 6.9 6.9 6.9 Rhenogran TBBS-80 0.5 0.5 0.5 0.5 0.5 0.5 Rhenogran MBTS-80 1.3 1.3 1.3 1.3 1.3 1.3 Rhenogran ZBEC-70 2 2 2 2 2 2 Rhenogran ZDBP-50 2 2 2 2 2 2 Rhenogran ZAT-70 0.6 0.6 0.6 0.6 0.6 0.6 Rhenogran S-80 0.75 0.75 0.75 0.75 0.75 0.75 Rhenogran DTDC-80 1 1 1 1 1 1 Vulkalent E/C 0.5 0.5 0.5 0.5 0.5 0.5 total 403.85 498.85 593.85 403.85 498.85 593.85 A) Kumho KEP2371; B) Arlanxeo Keltan 8550C; C) Example 1; D) Example 2

TABLE-US-00005 TABLE 4 Overview of compound ingredients used ingredient chemical composition supplier Corax N-550 carbon black Evonik Whiting BSH calcium carbonate Omya Sunpar 2280 paraphinic oil Sunoco ZnO aktiv zinc oxide Rhein Chemie Additives Edenor C 18 98-100 steanc acid Emery Oleochemicals PEG 4000 polyethylene glycol Merck milled sulfur 90/95 sulfur VWR International Rhenogran CaO-80 80% calcium oxide on carrier Rhein Chemie Additives Rhenogran TBBS-80 80% N-tert.-butyl-2-benzothiazyl sulfenamide Rhein Chemie Additives on carrier Rhenogran MBTS-80 80% dibenzothiazole disulfide on carrier Rhein Chemie Additives Rhenogran ZBEC-70 70% zinc-dibenzyl-dithiocarbamate on carrier Rhein Chemie Additives Rhenogran ZDBP-50 50% zinc dialkyldithiophosphate on carrier Rhein Chemie Additives Rhenogran ZAT-70 70% zinc amine dithiophosphate on carrier Rhein Chemie Additives Rhenogran S-80 80% sulfur on carrier Rhein Chemie Additives Rhenogran DTDC-80 80% caprolactam disulfide Rhein Chemie Additives Vulkalent E/C N-phenyl-N-(trichloromethylsulfenyl)-benzene Rhein Chemie Additives sulphonamide

[0076] Experimental Part and Test Methods

[0077] All compounds were prepared on a laboratory internal mixer (GK1,5 E1 from Harburg-Freudenberger Maschinenbau GmbH; ram pressure 7 bar, 45 rpm, 70% degree of filling and total mixing time 4 min). Chemicals of the vulcanization system were added on an open mill (200 mm diameter of the rolls; 20 rpm, 40 C. roll temperature and friction 1, 22). Test specimens have been prepared for all compounds by curing test plates of 2 mm and 6 mm thickness at 180 C. to a time equivalent to 1.1 and 1.25 times t90 (t90 is the time to reach 90% of maximum torque during the rheometer measurement).

[0078] Various mechanical and elastic properties were measured in accordance with the test methods listed in Table 5.

TABLE-US-00006 TABLE 5 Test methods. method standard characteristic abbreviation unit compound Mooney DIN 53523-3 Mooney viscosity (1 + 4) @ 100 C. compound ML (MU) viscosity Mooney DIN 53523-4 scorch time for 5% rise of torque versus t5s (sec.) scorch minimum torque @ 125 C. rheometry DIN 53529 torque difference MH-ML @ 180 C. DS (dNm) time to 1 dNm rise above minimum torque @ 180 C. ts2 (sec.) time to 90% of maximum torque @ 180 C. t90 (sec.) vulcanisate hardness DIN ISO 7619-1 hardness Hh (Sh A) tensile test DIN ISO 37 modulus at 100% elongation M100% (MPa) modulus at 300% elongation M300% (MPa) elongation at break eab (%) tensile strength TS (MPa) Delft tear test ISO 34-2 tear resistance tear (N/mm) compression DIN ISO 815 compression set for 24 hr @ 25 C. CS @ 25 C. (%) set test compression set for 24 hr @ 100 C. CS @ 100 C. (%) compression set for 24 hr @ 70 C. CS @ 70 C. (%) compression set for 24 hr @ 23 C. CS @ 23 C. (%) compression DVR VW-3307 compression set for 22 hr @ 90 C.; storage in CS @ 90 C.; (%) set test clamps 3 hr. @ 23 C.; 5 sec. relaxation 5 sec. compression set for 22 hr @ 90 C.; storage in CS @ 90 C.; (%) clamps 3 hr. @ 23 C.; 1 hr. relaxation 1 hr. compression set for 72 hr @ 23 C.; 5 sec. relaxation CS @ 23 C.; 5 sec. (%) compression set for 72 hr @ 23 C.; 1 hr. relaxation CS @ 23 C.; 1 hr (%)

[0079] Tables 6, 7 and 8 show the compound properties and the mechanical and elastic properties of the corresponding vulcanizates, based on compound formulations with about 600, 500 and 400 phr, respectively, with the four EPDMs investigated (cf. Tables 2 and 3).

[0080] The data from Table 6 are next compared with typical requirements for automotive, solid seals of i) tensile strength>8 MPa for test plaques combined with ii) the compression set according to DVR VW 3307 (22 hr. compression at 90 C., cooling for 3 hrs. in compressed state at room temperature and measurement after 1 hr. relaxation at room temperature) below 60%. K8550C does fulfill the compression set requirement CS 90 C.; 1 hr, but not the tensile strength requirement. KEP2731 does fulfill the tensile strength requirement, but not the compression set CS 90 C.; 1 hr requirement. The two EPDM examples according to the present invention fulfill both the tensile strength and compression set CS 90 C.; 1 hr requirements in this 600 phr compound. In FIG. 1 the tensile strength in MPa is plotted vs the compression set CS 90 C.; 1 hr in %, and the typical DVR VW 3307 specifications (top left quadrant) are given. For the vulcanizates based on examples 1 and 2 as of the present invention it can be seen that they fulfill the strong requirements of both a very high tensile strength of larger than 8 MPa and a compression set CS 90 C.; 1 hr below 60% for a total loading of about 600 phr. These properties are not achievable by the vulcanizates based on the respective commercial EPDM grades available for such purpose.

TABLE-US-00007 TABLE 6 Properties of compounds and vulcanizate for 593.85 phr compound formulation example example EPDM K8550C KEP2371 1 2 compound compound ML (MU) 49.0 54.9 50.6 67.0 t5s (sec.) 654 527 682 616 S (dNm) 11.9 11.9 10.99 12.0 ts2 (sec.) 53 47 53 50 t90 (sec.) 165 140 156 159 vulcanisate Hh (Sh A) 67.9 69.3 65.0 66.0 M100% (MPa) 3.2 3.7 3.2 3.3 M300% (MPa) 8.1 9.3 eab (%) 282 279 312 313 TS (MPa) 7.3 8.8 8.4 9.6 tear (N/mm) 27.5 32.3 32.2 32.5 CS @ 25 C. (%) 64.9 91.6 86.9 91.4 CS @ 100 C. (%) 30.2 29.1 34.5 31.1 CS @ 70 C. (%) 9.4 11.6 10.7 12.7 CS @ 23 C. (%) 4.6 11.5 6.2 7.8 CS @ 90 C.; 5 sec. (%) 63.5 70.2 61.8 59.9 CS @ 90 C.; 1 hr. (%) 55.2 62.3 57.9 54.4 CS @ 23 C.; 5 sec. (%) 20.9 28.6 22.0 20.1 CS @ 23 C.; 1 hr (%) 12.2 15.9 12.8 10.1

[0081] In a similar way, the two examples of the present invention combine a tensile strength larger than 8 MPa with a compression set at 23 C. according to DIN ISO 815 below 10% in the 600 phr compounds, whereas the commercial EPDM products do not.

[0082] For the 500 phr compound formulations (Table 7) only the two examples of the present invention combine a tensile strength larger than 10 MPa with a compression set CS 90 C.; 1 hr below 53% and a compression set at 23 C. according to DIN ISO 815 below 8%, whereas the commercial EPDM products do not. Finally, for the 400 phr compound formulations (Table 8) only the two examples of the present invention combine a tensile strength larger than 11 MPa with a compression set at 23 C. according to DIN ISO 815 below 8%.

TABLE-US-00008 TABLE 7 Properties of compounds and vulcanisate for 498.85 phr compound formulation. example example EPDM K8550C KEP2371 1 2 compound compound ML (MU) 53.4 63.0 60.0 75.7 t5s (sec.) 638 495 623 548 S (dNm) 13.9 13.8 13.63 14.4 ts2 (sec.) 50 44 49 46 t90 (sec.) 159 133 148 149 vulcanisate Hh (Sh A) 65.6 68.5 66.0 65.9 M100% (MPa) 3.4 4 3.4 3.4 M300% (MPa) 8.7 10.4 9.7 10.4 eab (%) 332 325 339 349 TS (MPa) 9.3 10.8 10.6 11.6 tear (N/mm) 37.7 35.3 36 38.9 CS @ 25 C. (%) 55.7 93.5 82.5 92.4 CS @ 100 C. (%) 28.5 26.1 30.0 27.4 CS @ 70 C. (%) 8.6 11.7 10.0 11.2 CS @ 23 C. (%) 4.7 10.3 6.3 6.6 CS @ 90 C.; 5 sec. (%) 54.4 62.9 52.9 54.0 CS @ 90 C.; 1 hr. (%) 49.5 53.7 49.7 46.4 CS @ 23 C.; 5 sec. (%) 18.9 23.0 19.5 20.4 CS @ 23 C.; 1 hr (%) 11.4 12.7 10.4 12.2

TABLE-US-00009 TABLE 8 Properties of compounds and vulcanisate for 403.85 phr compound formulation. example example EPDM K8550C KEP2371 1 2 compound compound ML (MU) 61.7 72.7 68.3 89.6 t5s (sec.) 622 490 627 530 S (dNm) 16.7 16.2 16.31 17.8 ts2 (sec.) 47 42 46 43 t90 (sec.) 153 124 153 144 vulcanisate Hh (Sh A) 66.8 68.4 65.2 65.5 M100cY0 (MPa) 3.2 3.6 3.3 3.4 M300% (MPa) 9 10.8 10.4 11.6 eab (%) 367 370 368 383 TS (MPa) 10.5 12.4 12.3 14.2 tear (N/mm) 35.4 40.3 37.9 40.4 CS @ 25 C. (%) 49.7 92.6 80.9 89.8 CS @ 100 C. (%) 25.8 24.4 27.0 23.8 CS @ 70 C. (%) 8.1 11.4 9.5 8.9 CS @ 23 C. (%) 5.1 10.3 5.8 6.4