Rubber replacement material comprising terpolymers

Abstract

The present invention provides a polyolefin composition, said composition comprising a terpolymer comprising a cross-linkable polyolefin comprising hydrolysable silane groups and a polar comonomer, the polyolefin composition further comprising a cross-linking catalyst and a silicon containing compound. The polar comonomer Is present in an amount of 5-35 wt %.

Claims

1. A polyolefin composition, said composition comprising: a terpolymer comprising (A) a cross-linkable polyolefin comprising hydrolysable silane groups, and (C) a polar comonomer, wherein the polar comonomer (C) is present in an amount of 5-35 wt % based on the total amount of the terpolymer, wherein said polyolefin composition further comprises: (B) a cross-linking catalyst, and (D) a silicon containing compound; and (E) a foaming agent; wherein said composition have Shore A values from 60 to 85; and wherein a compression set of said polyolefin composition is 15-40% at 100° C.

2. The polyolefin composition according to claim 1, wherein the polar comonomer is present in an amount of 20-31 wt %.

3. The polyolefin composition according to claim 1, wherein the polar comonomer is methyl acrylate.

4. The polyolefin composition according to claim 1, wherein said cross-linking catalyst is a Brönsted acid.

5. The polyolefin composition according to claim 1, wherein said cross-linking catalyst is a tin catalyst.

6. The polyolefin composition according to claim 1, wherein said composition have Shore A values from 61 to 82.

7. The polyolefin composition according to claim 1, wherein the compression set of said polyolefin composition is 18-35%, at 100° C.

8. The polyolefin composition according to claim 1, wherein the compression set of said polyolefin composition is 18-30%, at 23° C.

9. The polyolefin composition according to claim 1, wherein the compression set of said polyolefin composition is 5-15% at −25° C.

10. The polyolefin composition according to any one of the preceding claims, wherein MFR.sub.2 of said composition is 1-40 g/10 min.

11. The polyolefin composition according to claim 1, wherein said composition further comprises an antioxidant.

12. The polyolefin composition according to claim 1, wherein said composition is produced in a high-pressure reactor.

13. A method of manufacturing a weather seal comprising the polyolefin composition according to claim 1, said method comprising the steps of: extruding the polyolefin composition according to claim 1 into a profile cutting the extruded profile.

14. A weather seal comprising a polyolefin composition according to claim 1.

15. A method of manufacturing a roofing membrane comprising the polyolefin composition according to claim 1, said method comprising the steps of: extruding the polyolefin composition according to claim 1 to form a top layer and a bottom layer; calendaring a scrim layer between the top and the bottom layers to form an uncured roofing membrane element; and crosslinking the polyolefin composition of the top and the bottom layers in the uncured roofing membrane element at a curing temperature and a curing humidity to form the single ply roofing membrane.

16. A roofing membrane comprising a polyolefin composition according to claim 1.

17. A method of manufacturing a shoe sole comprising the polyolefin composition according to claim 1, said method comprising the steps of: extruding the polyolefin composition according to claim 1 and a foaming agent to form a cross-linkable polyolefin blend; injection or compression moulding the crosslinkable polyolefin blend into a shoe sole element; and crosslinking the crosslinkable polyolefin blend at a temperature greater than 150° C. and an ambient humidity to form a shoe sole.

18. A shoe sole comprising a polyolefin composition according to claim 1.

19. A method of manufacturing a hose comprising the polyolefin composition according to claim 1, said method comprising the steps of: extruding the terpolymer, the cross-linking catalyst and the silicone containing compound, and optionally a filler together to form an extruded crosslinkable polyolefin composition; cooling the extruded crosslinkable polyolefin composition; forming the extruded crosslinkable polyolefin composition into a hose element; and crosslinking the composition of the hose element to form the hose.

20. A hose comprising a polyolefin composition according to claim 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

Examples

(1) 1. Materials

(2) EPDM is Keltan 4450 obtained from Lanxess. The EPDM rubber compound for producing a seal was based on the present in the art formulation for EPDM seals, carbon black, stearic acid, zinc oxide, paraffin oil, TMTD and CBS accelerators and sulphur.

(3) Santoprene 121-58W175 is a thermoplastic vulcanizate (TPV) obtained from Exxon Mobil.

(4) Santoprene 121-60M200 is a thermoplastic vulcanizate (TPV) obtained from Exxon Mobil.

(5) JSR 1810B is a thermoplastic vulcanizate (TPV) from JSR group.

(6) JSR 1805B is a thermoplastic vulcanizate (TPV) from JSR group.

(7) TP1-TB3 are terpolymers comprising copolymer of ethylene with methyl acrylate comonomer and with vinyl trimethoxysilane comonomer. The properties of TP1-TP3 are shown in Table 1.

(8) TABLE-US-00001 TABLE 1 Product properties of the inventive compositions Properties of the polymer obtained from the reactor Acrylate VTMS MFR.sub.2 content T.sub.m content Polymer (g/10 min) (wt %) (° C.) (wt %) TP1 2 21 90 2.1 TP2 18 26 85 2.1 TP3 34 30 81 2

(9) Catalyst I is a masterbatch comprising dodecylbenzene sulphonic acid and a silicon containing compound.

(10) Catalyst II is a masterbatch comprising dioctyltin dilaurate and a silicon containing compound.

(11) 2. Measuring Methods and Procedures

(12) Melt Flow Rate

(13) The melt flow rate (MFR) is determined according to ISO 1133 and is indicated in g/10 min. The MFR is an indication of the flowability, and hence the processability, of the polymer. The higher the melt flow rate, the lower the viscosity of the polymer. The MFR2 of polypropylene is measured at a temperature 230° C. and a load of 2.16 kg. The MFR2 of polyethylene is measured at a temperature 190° C. and a load of 2.16 kg.

(14) Shore A

(15) Shore A measurement is performed according to the ASTM standard D2240.

(16) Gel Content

(17) The gel content was calculated according to ASTM D 2765-01. The gel content was measured from the plaques samples for compression set measurements, see “Sample preparation and compression set”.

(18) Content (wt % and mol %) of Polar Comonomer

(19) Comonomer content (wt %) of the polar comonomer was determined in a known manner based on Fourier transform infrared spectroscopy (FTIR) determination calibrated with 13 C-NMR as described in Haslam J, Willis H A, Squirrel D C. Identification and analysis of plastics, 2<nd> ed. London Iliffe books; 1972. FTIR instrument was a Perkin Elmer 2000, Iscann, resolution 4 cm.sup.−1.

(20) For determination of the comonomers, films with thickness 0.1 mm were prepared. The peak for the used comonomer was compared to the peak of polyethylene as evident for a skilled person (e.g. the peak for butyl acrylate at 3450 cm.sup.−1 was compared to the peak of polyethylene at 2020 cm.sup.−1). The weight-% was converted to mol-% by calculation based on the total moles of polymerisable monomers.

(21) VTMS Content in PE-Methylacrylate-Trimethylsiloxane Terpolymer

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

(23) Quantitative 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 standard broad-band inverse 5 mm probehead at 100° C. using nitrogen gas for all pneumatics. Approximately 100 mg of material was dissolved in approx. 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) using ditertiarybutylhydroxytoluen (BHT) (CAS 128-37-0) as stabiliser. Standard single-pulse excitation was employed utilising a 30 degree pulse, a relaxation delay of 3 s and no sample rotation. A total of 32 transients were acquired per spectra using 2 dummy scans. A total of 32 k data points were collected per FID with a dwell time of 60 μs, which corresponded to a spectral window of approx. 20 ppm. The FID was then zero filled to 64 k data points and an exponential window function applied with 0.3 Hz line-broadening. This setup was chosen primarily for the high resolution needed for comonomer content quantification.

(24) Quantitative 1H NMR spectra were processed, integrated and quantitative properties determined using custom spectral analysis automation programs. All chemical shifts were internally referenced to the residual protonated solvent signal at 5.95 ppm.

(25) Characteristic signals corresponding to the incorporation of both methyl acrylate and trimethylsiloxane were observed (brandolini01) and all comonomer contents calculated with respect to all other monomers present in the polymer.

(26) Characteristic signals resulting from incorporation of methyl acrylate, in various comonomer sequences, were observed. The methylacrylate incorporation was quantified using the integral of the signal at 3.65 ppm assigned to the 1MA sites, accounting for the number of reporting nuclei per comonomer:
MA=I.sub.1MA/3

(27) ##STR00003##

(28) Characteristic signals resulting from incorporation of vinyltrimethylsiloxane, in various comonomer sequences, were observed. The vinyltrimethylsiloxane incorporation was quantified using the integral of the signal at 3.56 ppm assigned to the 1VTMS sites, accounting for the number of reporting nuclei per comonomer:
VTMS=I.sub.1VTMS/9

(29) ##STR00004##

(30) Characteristic signals resulting from the additional use of BHT as stabiliser, were observed. The BHT content was quantified using the integral of the signal at 6.93 ppm assigned to the ArBHT sites, accounting for the number of reporting nuclei per molecule:
BHT=I.sub.ArBHT/2

(31) The ethylene comonomer content was quantified using the integral of the bulk aliphatic (bulk) signal between 0.00-3.00 ppm. This integral included the *MA and αMA sites from isolated methylacrylate incorporation, the *VTMS and αVTMS sites from isolated vinyltrimethylsiloxane incorporation and the aliphatic sites from BHT as well as the sites from polyethylene sequences. The total ethylene comonomer content was calculated based on the bulk integral and compensating for the observed comonomer sequences and BHT:
E=(¼)*[I.sub.bulk−3*MA−3*VTMS−21*BHT]

(32) It should be noted that an insignificant error is introduced due to the inability to compensate for the two saturated chain ends (S) without associated branch sites.

(33) The total mole fractions of methylacrylate and vinyltrimethylsiloxane in the polymer were calculated as:
fMA=MA/(E+MA+VTMS)
fVTMS=VTMS/(E+MA+VTMS)

(34) The total comonomer incorporations of methylacrylate and vinyltrimethylsiloxane in mole percent were calculated from the mole fractions in the standard manner:
MA[mol %]=100*fMA
VTMS[mol %]=100*fVTMS

(35) The total comonomer incorporations of methylacrylate and vinyltrimethylsiloxane in weight percent were calculated from the mole fractions in the standard manner:
MA[wt %]=100*(fMA*86.09)/((fMA*86.09)+(fVTMS*148.23)+((1−fMA−fVTMS)*28.05))
VTMS[wt %]=100*(fVTMS*148.23)/((fMA*86.09)+(fVTMS*148.23)+((1−fMA−fVTMS)*28.05))

(36) Reference is made to A. J. Brandolini, D. D. Hills, “NMR spectra of polymers and polymer additives”, Marcel Deker Inc., 2000

(37) Melt Temperature (T.sub.m) and Heat of Fusion (H.sub.f)

(38) T.sub.m was measured with Mettler TA820 differential scanning calorimetry (DSC) on 5 to 10 mg samples. DSC is run according to ISO 3146/part 3/method C2 in a heat/cool/heat cycle with a scan rate of 10° C./min (heating and cooling) in the temperature range of +23 to +210° C. The melting temperature and heat of fusion (H.sub.f) are determined from the second heating step. The melting temperatures were taken as the peaks of endotherms.

(39) Preparation of TP1-TP3

(40) TP1-TP3 were produced in a commercial high pressure tubular reactor at a pressure 2500-3000 bar and max temperature 250-300° C. using conventional peroxide initiator. Ethylene monomer, methyl acrylate (MA) polar comonomer and vinyl trimethoxy silane (VTMS) comonomer (silane group(s) containing comonomer) were added to the reactor system in a conventional manner. CTA was used to regulate MFR as well known for a skilled person.

(41) Sample Preparation and Compression Set

(42) The sample preparation for compression set measurement at DIK was done the following:

(43) The tested materials were dry blended (mixed) with two different catalyst masterbatches, a 5% catalyst I and 4% catalyst II and then extruded into tapes. Tape samples were produced on a Collin extruder (Teach-Line E20T) with a temperature profile of 120-130-140° C. The tape samples had a thickness of 2 mm and a width of 40 mm.

(44) Plaques samples for compression set were made by compression moulding the tapes to get a thickness of around 6 mm for the compression set test. After compression moulding the plaques were merged in hot water (50° C.) for 24 hours to fully crosslink the material before measuring the compression set. The actual specimen is then cut from the plaque and fixed between two metal plates at room temperature.

(45) The compression is set to be 25% of the thickness of the specimen by utilizing different spacers. The compressed samples are then stored at the selected temperature for 24 hours. Thereafter, the samples are moved to room temperature and released from compression. After 30 minutes of recovery at room temperature, the samples are measured to determine the compression set. The compression set is measured according to DIN ISO 815-1:2010-09, method A, specimen B.

(46) 3. Results

(47) TABLE-US-00002 TABLE 2 Melt EMA Temper- VTMS (wt %) ature (wt %) Gel By (° C.) by MFR.sub.2 Content Shore Compression set (%) Sample Polymer Catalyst NMR by DSC NMR (g/min) (%) A −25° C. 23° C. 100° C. CE1 EPDM — 4 8.3 53.6 CE2 Santoprene — 62 18 39 121- (125° C.) 58W175 CE3 Santoprene — 61 26 (70° C.) 121- 33 60M200 (100° C.) CE4 JSR 1810B — 80 22.4 34.6 51.3 CE5 JSR 1805B — 80 20.0 32.1 64.7 IE1 TP1 5% 21 90 2.1 2 91.2 82 7.6 18.9 31.0 catalyst I IE2 TP1 4% 21 90 2.1 2 79.2 82 9.7 19.6 28.1 catalyst II IE3 TP2 5% 26 85 2.1 18 89.0 72 6.0 18.6 19.4 catalyst I IE4 TP2 4% 26 85 2.1 18 77.3 72 8.7 21.8 33.1 catalyst II IE5 TP3 5% 30 81 2 34 82.3 61 7.1 18.5 21.9 catalyst I IE6 TP3 4% 30 81 2 34 55.3 61 6.3 21.9 33.1 catalyst II

(48) Ethylene-methyl acrylate-vinyl silane terpolymers with 21-30 w-% methyl acrylate show near as good compression set at −25° C., slightly higher compression set at room temperature and clearly lower compression set at 100° C. compared to EPDM (Table 2) and comparable compression set with Santoprene-based samples at room and high temperatures.

(49) Further, the samples comprising the composition of the present invention clearly show lower compression set values compared to JSR-based samples at all temperatures.

(50) It is believed that the combination of high Shore A and high gel content of the inventive samples is providing the advantageous compression set properties.

(51) Although the present invention has been described with reference to various embodiments, those skilled in the art will recognize that changes may be made without departing from the scope of the invention. It is intended that the detailed description be regarded as illustrative, and that the appended claims including all the equivalents are intended to define the scope of the invention.