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AssigneeExxonMobil Chemical Patents Inc.
InventorsAnthony G. Karandinos, Keith A. Nelson, Jean M. Tancrede, Bruce A. Harrington, David J. Lohse, Olivier J. F. Georjon, Kenneth Lewtas, Sudhin Datta, Charles Cozewith
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An adhesive blend is described that can include a semi-crystalline copolymer of propylene and at least one comonomer selected from the group consisting of ethylene and at least one C4 to C20 α-olefin, the copolymer having a weight average molecular weight (Mw) from about 15,000 to about 200,000; an melt index (MI) from about 7 dg/min to about 3000 dg/min as measured by ASTM D 1238(B), and a (Mw/Mn) of approximately 2. Various production processes are also described. Also described are adhesive compositions and methods for making adhesive compositions having polymers or polymer blends with melt flow rates (MFRs) equal to and above 250° dg/min. at 230° C. Certain specific embodiments of the invention involve the use of a free radical initiator, e.g., a peroxide.
An adhesive composition comprising a semi-crystalline copolymer of propylene and at least one comonomer selected from the group consisting of ethylene and C4 to C20 α-olefins, wherein the copolymer has a propylene content of greater than 65 mole percent a weight average molecular weight (Mw) of from about 15,000 to about 200,000, a melt index (MI) of from about 7 dg/min to about 3000 dg/min as measured by ASTM D 1238(B), a weight average molecular weight/number average molecular weight ratio (Mw/Mn) of approximately 2, an MFR of greater than 250 dg/min. and a heat of fusion of from about 30 to about 80 J/g as determined by DSC.
The adhesive composition of claim it wherein the melt index of the semi-crystalline copolymer is from about 20 dg/min to about 900 dg/min.
An adhesive composition having an MFR greater than about 250 dg/min. at 230° C., the composition comprising a blend of a crystalline polymer and a random copolymer produced by copolymerizing propylene and at least one of ethylene and alpha-olefins having 20 or fewer carbon atoms, the random copolymer having a crystallinity of at least about 2% and no greater than about 65% derived from stereoregular polypropylene sequences and a melting point of from about 25° C. to about 105° C.
Dependencies are inferred from the claim text.