Unsaturated ethylene-non conjugated diene copolymers and prepara

Details Unsaturated ethylene-non conjugated diene copolymers and prepara Unsaturated ethylene-non conjugated diene copolymers and prepara

1994-04-21

1996-07-23

Zitomer, Fred

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

526279, 526319, 526332, 526336, 5263403, C08F23620, C08F 1234

Patent

active

055390757

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to an unsaturated ethylene copolymer and a method for the production thereof. More specifically, the invention concerns an unsaturated ethylene copolymer having an increased degree of unsaturation and being producted by radical polymerisation through a high-pressure process.
Normally, polyethylene produced by radical polymerisation, so-called LDPE, has a low degree of unsaturation in the order of 0.1 double bonds/1000 carbon atoms. In many situations, it is desirable to use polymers having a higher degree of unsaturation, which may serve as seat for chemical reactions, such as the introduction of functional groups into the polymer molecule or the cross-linking of the polymer. It is known that an increased level of double bonds can be obtained in polyethylene produced by organometallic catalysis, i.e. involving a coordination catalyst, by introducing as comonomers compounds having several double bonds, in which case only one bond is used for polymerising the comonomer into the polymer chain. EP 0 008 528 and JP 0 226 1809, for instance, disclose such prior-art techniques. Further, EP 0 260 999 relates to copolymers of ethylene and dienes having 4-18 carbon atoms, such as 1,4-hexadiene, in which case polymerisation is performed by means of a so-called metallocene catalyst at a high pressure. Mention may also be made of WO 91/17194 which concerns copolymers of .alpha.-olefins, such as ethylene, and .alpha.,.omega.-dienes having 7-30 carbon atoms, preferably 8-12 carbon atoms, such as 1,9-decadiene, in which case polymerisation is coordination-catalysed. Moreover, U.S. Pat. No. 3,357,961 discloses the production of a copolymer of ethylene and 1,5-hexadiene by coordination-catalysed low-pressure polymerisation. One may further mention Chemical Abstracts, Vol. 116, No. 4, 27th Jan. 1992, p. 15, Abstract 21674b (JP 0 322 1508, published on 30th Sep. 1991); Chemical Abstracts Vol. 101, No. 12, 17th September 1984, p. 42, Abstract 92065e (JP 595 6412 published on 31st Mar. 1984); and Chemical Abstracts, Vol. 69, No. 74, 9th Dec. 1968, Kiti, Itsuo: "Ethylene-1,4-hexadiene copolymers" p. 9135, Abstract 97310m. These abstracts relate to copolymers of ethylene and non-conjugated dienes, such as 1,4-hexadiene, 1,7-octadiene and 1,9-decadiene, and involve the use of coordination-catalysed polymerisation.
As already mentioned, the above references relate to coordination-catalysed polymerisation. Coordination-catalysed polymerisation and radical-initiated polymerisation are two fundamentally different types of polymerisation, resulting in different types of polymers. While coordination-catalysed polymerisation essentially yields unbranched linear polymer molecules, radical-initiated polymerisation yields heavily branched polymer molecules with long side chains. Consequently, polymers produced by the two processes have different properties. For instance, polymers produced by coordination-catalysed polymerisation have a higher density than those produced by radical-initiated polymerisation. They also have a higher melt viscosity at the same melt index, which means that the polymers produced by a radical-initiated high-pressure process are, in general, easier to process.
It should be emphasised that the fact that coordination-catalysed polymerisation and radical-initiated polymerisation are two fundamentally different processes means that no conclusions about one process can be drawn from the other. If, in coordination-catalysed polymerisation involving the addition of diene, only one double bond of the diene reacts, one may thus not conclude that this is also the case in radical-initiated polymerisation. Whether the diene reacts or not in coordination-catalysed polymerisation depends on the action produced by the coordination catalyst employed. Since radical-initiated polymerisation does not involve any such catalyst, there is no reason to assume that the diene will react in the same way in radical-initiated polymerisation.
On the contrary, in FR 2,660,660, for instance, non-conjugated dienes ar

REFERENCES:
patent: 2933480 (1960-04-01), Gresham
patent: 3357961 (1967-12-01), Makowski et al.
patent: 5190862 (1965-06-01), Boghetich
patent: 5298582 (1994-03-01), Brusson
Chemical Abstract, vol. 116, No. 4, 27 Jan. 1992, p. 15, 21674b.
Chemical Abstract, vol. 69, No. 24, 9 Dec. 1968, 97310m.
International Search report-PCT/SE92/00491.
International-Type Search Report-SE91/00475.
Chemical Abstract, vol. 101, No. 12, 17 Sep. 1984, 92065e.
Encyclopedia of Polymer Science and Engineering, vol. 6, Emulsion Polymerization to Fibers, Manufacture, 1986, by John Wiley Sons, Inc.
Extract from H. Bennet, Concise Chemical and Technical Dictionary, Third Ed., Chemical Publishing Col, Inc., New York, NY (1974).
Kaltenbacher et al., "Polyethylene for Extrusion Coating", Plastics, 34:168-171 (Feb. 1969).

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