Petroleum resin and pressure sensitive adhesive formulations utilizing same as tackifier
AssigneeExxon Research & Engineering Co.
InventorsVincent L. Hughes, Francisco M. Benitez
Life of this patent
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Abstract
This invention relates to pressure sensitive adhesive formulations which include a block copolymer of styrene and isoprene such as Kraton.RTM. D and a tackifying resin derived from petroleum feedstock polymerized in the presence of aluminum chloride and having a Mw ranging from 800 to 960, a Mn ranging from 500 to 600 with a Mw/Mn ratio of from 1.3 to 1.9, a softening point of 78.degree. to 81.degree. C. and a glass transition temperature of about 50.degree. C. whereby the adhesive formulations have a rolling ball tack of less than 5 cm., a 180.degree. peel of higher than 3 pounds per inch, a 90.degree. quick stick of higher than 3 pounds per inch and a Polyken tack of higher than 1,000 g/cm.sup.2.
Claims8
A petroleum resin containing a major proportion of the aluminum halide catalyzed polymer of the combination of pentadiene 1,3 and 2-methyl butenes, a number average molecular weight (Mn) of from 500 to 600, a weight average molecular weight (Mw) of from 800 to 960, a Mw/Mn ratio of 1.3 to 1.9 and a softening point ranging from 78.degree. C. to 81.degree. C.
A process for producing a petroleum resin having a number average molecular weight (Mn), softening point and glass transition temperature suitable for use as a tackifying additive for an adhesive composition containing a block copolymer of styrene and isoprene which comprises polymerizing in the presence of aluminum chloride a C.sub.5 -C.sub.6 fraction from steam cracked naphtha or light refinery streams, said C.sub.5 -C.sub.6 fraction having a composition comprising a major proportion of piperylene and 2-methyl butenes, a cyclic diolefin to monoolefin weight ratio of no greater than 0.03 and a total diolefin to 2-methyl butenes weight ratio of from 0.8 to 1.0 and recovering a petroleum resin having a Mn of from 500 to 600, a softening point of from 78.degree. C. to 81.degree. C. and a glass transition temperature of from 45.degree. C. to 55.degree. C.
A pressure sensitive adhesive formulation which comprises (a) a block copolymer of styrene isoprene and styrene and (b) about 125 to 175, preferably 150, parts by weight per 100 parts of weight of said block copolymer of a petroleum resin containing a major proportion of the aluminum halide catalyzed polymerizate of the combination of pentadiene 1,3 and 2-methyl butenes, a number average molecular weight (Mn) of from 500 to 600, a weight average molecular weight (Mw) of from 800 to 960, a Mw/Mn ratio of 1.3 to 1.9 and a softening point ranging from 78.degree.-81.degree. C. whereby a rolling-ball tack of from 2 to 4 cm and a polyken tack of 1600 gm/cm.sup.2 to 1900 gm/cm.sup.2 are obtained.
Dependencies are inferred from the claim text.