Patent ID: 6103814
Filing Date: 2000-08-15
Classification: A61F,C08L,C09J

Abstract:
A hot-melt adhesive composition which comprises:(a) about 50 to about 150 parts by weight of a styrenic block copolymer;(b) about 20 to about 450 parts by weight of a tackifying resin which, when incorporated into a reference composition consisting of 100 parts by weight of a styrene-isoprene-styrene copolymer having a styrene content of about 20 to 30% by weight, 250 parts by weight of said tackifying resin, 50 parts by weight of a paraffinic/napthenic (70/30 weight/weight) extender oil and 2 parts by weight of a stabilizer consisting essentially of pentaerythrityl-tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionate] , leads to the following properties of said reference composition:a melt viscosity of about 60,000 mPa.s or less at a temperature of about 120.degree. C.;a tan .delta. value of about 3.5 or less, wherein tan .delta. is defined as the ratio between the loss modulus (G"") and the storage modulus (G') of said composition;an elastic retention on natural latex rubber (200%) after 4 h at about 40.degree. C. of about 70% or more; anda crossover temperature between G' and G"" (tan .delta.=1) of about 95.degree. C. or less,wherein G"" and G' of said composition are determined on a Rheometrics Mechanical Spectrometer (RDS-II) using 8 mm circular shaped parallel plates with a 2 mm gap distance over a temperature range from about -60.degree. C. up to about 140.degree. C. and a frequency of 10 radians/sec.