Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1998-01-12
2001-02-20
Teskin, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S124300, C526S125600, C526S348400, C526S348600, C526S905000, C526S916000, C524S128000, C524S323000, C524S330000, C524S333000, C524S342000, C524S343000, C524S348000, C524S394000, C524S399000, C524S400000, C524S579000
Reexamination Certificate
active
06191246
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to polymerization. It relates in particular to a polymer, and to a process for producing such a polymer.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, there is provided a polymer which comprises a polymerization product obtained by polymerizing at least ethylene, 1-pentene and 1-hexene.
In other words, in accordance with the first aspect of the invention, there is provided a polymer of at least ethylene, 1-pentene and 1-hexene.
In particular, the polymerization product or polymer may be a terpolymer of ethylene, 1-pentene and 1-hexene.
Thus, according to a second aspect of the invention, there is provided a terpolymer of ethylene, 1-pentene and 1-hexene.
The Applicant has found that, generally, such terpolymers exhibit good properties when moulded into film. These properties are controlled mainly by the relative proportions of ethylene, 1-pentene and 1-hexene in the terpolymer.
The molar ratio of ethylene to the sum of n-pentene-1 and n-hexene-1 in the terpolymer may be between 99.9:0.1 and 90.0:10.0, while the molar ratio of 1-pentene to 1-hexene therein may be between 0.1:99.9 and 99.9:0.1.
The terpolymer may have a melt flow rate, as measured according to ASTM D 1238, in the range of about 0.01 to about 100 g/10 min.
The terpolymer may have a density, as measured according to ASTM D 1505, in the range of about 0.89 to about 0.95 g/cm
3
.
In a first embodiment of the invention, the terpolymer may, when it is bottom blown into a film having a thickness of 30 microns on a 31.77 mm extruder with 220° C. melt temperature using a 2:1 blow ratio, comply with the following requisites:
(a) a melt flow index, as measured according to ASTM D 1238, of 0.01 to 100 g/10 minutes;
(b) a density, as measured according to ASTM D 1505, of 0.890 to 0.950 g/cm
3
;
(c) an impact strength, as measured according to ASTM D 1709, of greater than 60 g;
(d) a tear strength, as measured according to ASTM D 1922, of greater than 3.0 g/&mgr;m in the machine direction (MD) and greater than 12 g/&mgr;m in the transverse direction (TD); and
(e) contains units derived from 1-pentene and 1-hexene between 0.1 and 10 molar % as determined by
13
C NMR (samples dissolved in 1.2 dichlorobenzene).
Such a polymer thus has superior impact strength and good tear properties when blown into a film.
In a second embodiment of the invention, the terpolymer may, when it is bottom blown into a film having a thickness of 30 microns on a 31.77 mm extruder with 220° C. melt temperature using a 2:1 blow ratio, comply with the following requisites:
(a) a melt flow index, as measured according to ASTM D 1238, of 0.01 to 100 g/10 minutes;
(b) a density, as measured according to ASTM D 1505, of 0.890 to 0.950 g/cm
3
;
(c) an impact strength, as measured according to ASTM D 1709, of greater than 50 g;
(d) a tensile strength at break, as measured according to ASTM D 882, of greater than 25 MPa in the machine direction (MD) and greater than 25 MPa in the transverse direction (TD); and
(e) contains units derived from 1-pentene and 1-hexene between 0.1 and 10 molar % as determined by
13
C NMR (samples dissolved in 1,2dichlorobenzene).
Such a polymer thus has superior impact strength and good tensile strength at break when blown into a film.
In a third embodiment of the invention, the terpolymer may, when it is bottom blown into a film having a thickness of 30 microns on a 31.77 mm extruder with 220° C. melt temperature using a 2:1 blow ratio, comply with the following requisites:
(a) a melt flow index, as measured according to ASTM D 1238, of 0.01 to 100 g/10 minutes;
(b) a density, as measured according to ASTM D 1505, of 0.890 to 0.950 g/cm
3
;
(c) an impact strength, as measured according to ASTM D 1709, of greater than 40 g;
(d) a tensile strength at yield, as measured according to ASTM D 882, of greater than 15 MPa in the machine direction (MD) and greater than 14 MPa in the transverse direction (TD); and
(e) contains units derived from 1-pentene and 1-hexene between 0.1 and 10 molar % as determined by
13
C NMR (samples dissolved in 1,2dichlorobenzene).
Such a polymer thus has good impact strength and good tensile strength at yield when blown into a film.
In a fourth embodiment of the invention, the terpolymer may, when it is injection moulded according to ASTM D 647, comply with the following requisites:
(a) a melt flow index, as measured according to ASTM D 1238, of 0.01 to 100 g/10 minutes;
(b) a density, as measured according to ASTM D 1505, of 0.890 to 0.950 g/cm
3
;
(c) an Izod notched impact strength, as measured according to ASTM D 256, of between 5 and 60 kJ/m
2
;
(d) a tensile strength at yield, as measured according to ASTM 638 M, of between 10 MPa and 25 MPa;and
(e) contains units derived from 1-pentene and 1-hexene between 0.1 and 10 molar % as determined by
13
C NMR (samples dissolved in 1,2dichlorobenzene).
Such a polymer thus has a good balance of impact strength and tensile strength at yield, when injection moulded.
More particularly, the terpolymer may be that obtained by reacting ethylene, 1-pentene and 1-hexene in at least one reaction zone, while maintaining the reaction zone at a pressure in the range between atmospheric pressure and 60 kg/cm
2
, and at a temperature between 30° C. and 120° C. in the presence of a catalyst or catalyst system.
Thus, according to a third aspect of the invention, there is provided a process for producing a polymer, which process comprises reacting at least ethylene, 1-pentene and 1-hexene in at least one reaction zone, while maintaining the reaction zone at a pressure between atmospheric pressure and 60 kg/cm
2
, and at a temperature between 30° C. and 120° C., in the presence of a catalyst system, thereby to produce a polymerized product.
The polymerized product or polymer may, as mentioned hereinbefore, be a terpolymer of said ethylene, 1-pentene and 1-hexene.
The polymerization reaction may be effected in a slurry phase. The polymerization reaction may be performed in a substantially oxygen and water free state or atmosphere, and may be effected in the presence or absence of an inert saturated hydrocarbon.
A slurrying agent or solvent is thus required, and may be an inert saturated hydrocarbon. Preferred saturated hydrocarbons suitable for use as slurrying agents or solvents are aliphatic or cyclo-aliphatic liquid hydrocarbons, such as hexane and heptane.
While the reaction temperature can be in the range of 30° C. to 120° C. as stated hereinbefore, it is preferably in the range of 50° C. to 100° C. and most preferably in the range of 60° C. to 90° C.
While the pressure can be in the range of atmospheric pressure to 60 kg/cm
2
as stated hereinbefore, it is preferably in the range 3 kg/cm
2
to 30 kg/cm
2
, still more preferably in the range 4 kg/cm
2
to 18 kg/cm
2
.
The catalyst or catalyst system may be a Ziegler-Natta based catalyst or catalyst system. Any suitable Ziegler-Natta catalyst or catalyst system for ethylene polymerization can, at least in principle, be used. A catalyst system comprising a titanium based Ziegler-Natta catalyst, and, as co-catalyst, an aluminium compound is preferred. The most preferred is a titanium-magnesium chloride supported Ziegler-Natta catalyst having a productivity of at least 25 kg polymer/gram of catalyst, where the said catalyst has the ability to incorporate at the same time about the same level of 1-pentene and 1-hexene in the polyethylene chain.
In particular, the Ziegler-Natta catalyst may be that obtained by
(i) adding dibutyl ether under inert conditions to a suspension of anhydrous magnesium chloride-in an inert saturated hydrocarbon liquid, with the molar ratio of anhydrous magnesium chloride to dibutyl ether being between 0.3:1 and 3:1, preferably between 1:1 and 2:1, and stirring the resultant mixture for a period of 30 minutes to 10 hours, preferably from 4 to 6 hours, at room temperature;
(ii) adding triethylaluminium dropwise to the suspension, with the molar ratio of triethylaluminium to anhydrous magnesium chloride being between 1:1 and 6:1, prefe
Joubert Dawid Johannes
Loggenberg Peter
Potgieter Ignatius Hendrik
Tincul Ioan
(Sasol Technology (Proprietary) Limited)
Ladas and Parry
Teskin Fred
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