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AssigneeExxon Research & Engineering Co.
InventorsVincent L. Hughes, Ralph W. Looney
Estimating the term…
This invention relates to pressure sensitive adhesive formulations which include a saturated midblock thermoplastic elastomer such as a block copolymer of polystyrene and hydrogenated polydiene such as Kraton.RTM. G and a fully saturated tackifying resin derived from petroleum feedstock polymerized in the presence of aluminum chloride and having a Mn ranging from 400 to 800, a softening point of 40.degree. to 70.degree. C. and a glass transition temperature less than 45.degree. C. whereby the adhesive formulations have a rolling ball tack of less than 10 cm., a 180.degree. peel of from 1 to 4 pounds per inch, a 90.degree. quick stick of from 0.5 to 2.0 pounds per inch and a Polyken probe tack of higher than 400 g/cm.sup.2 with a formulation containing 100 to 180 phr of the saturated tackifying resin.
A fully saturated aliphatic petroleum resin possessing in its backbone structure a preponderance of substituted cyclohexane rings and having a number average molecular weight of (Mn) of 400 to 800, a softening point of 40.degree. C. to 70.degree. C., a glass transition temperature (Tg) of less than 45.degree. C. and, when admixed at the total weight level of 60% with a polystyrene-hydrogenated polydiene-polystyrene saturated midblock thermoplastic elastomer of Mn from about 30,000 to about 200,000 as measured by GPC, provides a HMPSA having a rolling ball tack of less than 10 cm and a Polyken probe tack greater than 400 gm/cm.sup.2, said resin being produced by the Friedel-Crafts polymerization of a C.sub.5 -C.sub.6 fraction from steam cracked naphtha or light refinery streams having a boiling range from 20.degree. C. to 80.degree. C., said resin having a major proportion of the polymerizable content comprising piperylene and 2-methyl-2-butene or similar branched olefins.
A hot melt pressure sensitive adhesive (HMPSA) formulation comprising (a) a saturated midblock thermoplastic elastomer and (b) about 100 to 180 parts by weight per 100 parts by weight of said elastomer of a fully saturated aliphatic petroleum resin possessing in its backbone structure a preponderance of substituted cyclohexane rings and having a number average molecular weight (Mn) of 400 to 800, a softening point of 40.degree. C. to 70.degree. C., a glass transition temperature (Tg) of less than 45.degree. C. and, when admixed at the total weight level of 60% with a polystyrene-hydrogenated polydiene-polystyrene saturated midblock thermoplastic elastomer of Mn from about 30,000 to about 200,000 as measured by GPC, provides a HMPSA having a rolling ball tack of less than 10 cm and a Polyken probe tack greater than 400 gm/cm.sup.2, said resin being produced by the Friedel-Crafts polymerization of a C.sub.5 -C.sub.6 fraction from steam cracked naphtha or light refinery streams having a boiling range from 20.degree. C. to 80.degree. C., said resin having a major proportion of the polymerizable content comprising piperylene and 2-methyl-2-butene or similar branched olefins.
Dependencies are inferred from the claim text.