Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Patent
1985-02-04
1987-09-01
Smith, Edward J.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
526159, 5263482, 5263483, 5263486, C08F 214, C08F2106
Patent
active
046909915
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention concerns a procedure for making mixed polymers of ethylene and long-chained alpha olefins. To be more precise, the invention concerns a procedure for making copolymers of ethylene and long-chained alpha olefins in which the density and melting point of the polymer can within given limits be regulated independent of each other and in which the quantity of long-chained alpha olefin can be easily regulated in a wide range in suspension polymerization.
For copolymerizing ethylene with olefins with the purpose of making LLDP (linear low density polyethylene) a number of commercial procedures are known in prior art, in which the most commonly used alpha olefins are 1-butylene and 1-octylene. In suspension and gas phase polymerization, 1-butylene is as a rule used, whereas in solution polymerization 1-octylene is used. The tensile strength, tearing strength and piercing strength of films made from copolymers are as a rule better when the comonomer is a long-chained alpha olefin, and it is therefore advantageous to be able to include them in the polymer.
Copolymerization of ethylene and long-chained alpha olefins containing more than eight carbon atoms by solution and gas phase polymerizing is commonly known in the patent literature. In suspension polymerization, in contrast, long-chained alpha olefins containing more than eight carbon atoms could not be used because at the low temperatures employed, the reactivity of long-chained alpha olefins is not sufficient. If it is specifically desired to make copolymers in which the quantity of long-chained alpha olefin is relatively high, one would have to use excessively high alpha olefin monomer contents in suspension polymerization. This, however, entails the drawback that the polymer being produced swells and the reactor gets dirty. The proportion of long-chained alpha olefin in the polymer still cannot be made high enough in this way. As a result, the making of copolymers of ethylene and long-chained alpha olefins by suspension polymerizing is not commercially practiced, and even in other methods the use of copolymers with more than eight carbon atoms is not often presented, not even in the examples of patent specifications.
SUMMARY OF THE INVENTION
According to the invention, it has been unexpectedly found that by polymerizing ethylene and alpha olefins containing at least eight carbon atoms by the suspension method at a temperature under 120.degree. C., it is possible in a simple way to increase the reactivity of long-chained alpha olefins. Since in this instance no excess of the long-chained alpha olefin monomer need be used, swelling of the polymer that is obtained and soiling of the reactor are also avoided. Through the increase of reactivity, the proportion of long-chained alpha olefin in the polymer can be significantly increased.
The procedure of the invention for making mixed polymers of ethylene and alpha olefins containing at least eight carbon atoms in the presence of a catalyst of Ziegler-Natta type to become mixed polymers in which the quantity of alpha olefins containing at least eight carbon atoms can be regulated within 0.01 to 15 percent by weight, is characterized in that polymerization is carried out at a temperature not higher than 120.degree. C. in a fluid in which the polymer that is produced is insoluble, and that the monomer mixture contains, for the purpose of increasing the reactivity of the long-chained alpha olefin, 0.01 to 2.0 mols per dm.sup.3 short-chained alpha olefin with no more than five carbon atoms.
BRIEF DESCRIPTION OF THE DRAWINGS
The FIGURE illustrates relationship between two components in the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The use of monomer mixtures containing long-chained alpha olefin and 1-butylene is in itself known in the art. For instance, in the European Patent Application No. 0 010 428, a procedure is disclosed for mixed polymerizing of ethylene, alpha olefin containing 3-4 carbon atoms and long-chained alpha olefin containing 5
REFERENCES:
patent: 3222332 (1965-12-01), Duck et al.
patent: 3645992 (1972-02-01), Elston
patent: 4076698 (1978-02-01), Anderson et al.
patent: 4304890 (1981-12-01), Suzuki et al.
patent: 4322514 (1982-03-01), Miyoshi et al.
Neste Oy
Smith Edward J.
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