Absorbent article containing a foam comprising crosslinked polymers made from 1,3,7-octatriene and like conjugated polyenes

An absorbent article especially suitable for absorbing and retaining aqueous body fluids, said article comprising:

• I) a backing sheet;
• and
• II) an absorbent core associated with said backing sheet such that said absorbent core is positioned between said backing sheet and the fluid discharge region of the wearer of the article, said absorbent core comprising a polymeric foam which absorbs aqueous body fluids, said polymeric foam comprising a hydrophilic, flexible, nonionic foam structure of interconnected open cells and which is made by polymerizing a water-in-oil emulsion having:
• 1) an oil phase comprising:
• a) from about 80 to about 97% by weight of a monomer component comprising:
• i) from about 60 to about 90% by weight of a polyene selected from the group consisting of 1,3-hexadiene- 1,3-octadiene, 2,3-dimethyl-1 ,3-butadiene, 2-ethyl-1,3-butadiene, 2-amyl-1,3-butadiene, 7-methyl-3-methylene-1,6-octadiene, 1,3,7-octatriene and mixtures thereof;
• ii) from about 10 to about 40% by weight of a crosslinking agent selected from the group consisting of ethylene glycol dimethacrylate, diethylene glycol dimethacrvlate, 1,6-hexanediol diacrylate, 2-butenediol dimethacrylate, ethylene glycol diacrylate, trimethylolpropane triacrylate and trimethacrylate, and mixtures thereof;
• iii) up to about 20% by weight a compatible comonomer selected from the group consisting of chloroprene, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoro-propylene, styrene, o-meth-oxystyrene, p-methoxy-styrene, m-methoxystyrene, o-methyl styrene, o-phenyl styrene, vinyl naphthalene, vinyl chloride, vinyl fluoride, vinylidene chloride, vinylidene fluoride, vinylidene bromide, acrylic acid, chloroacrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, butyl methacrylate, acrylamide, N-methylacrylam ide, N,N-dimethylacrylamide, N,N-dimethyl-methacrylamide, acrylonitrile, methacryl-onitrile, maleic anhydride, dimethyl maleate, vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, methyl vinyl ketone, ethyl vinyl ketone, and isobutyl vinyl ketone;
• butadiene, isoprene, piperylene, cyclopentadiene, norbomadiene, dicyclopentadiene, vinylpyridine, N-vinylcarbazole, N-vinylpyrrolidine, acrolein, vinylferrocene, vinyltitanocene, methyl vinylsulfone, vinylpyridine, 2-vinylbutadiene, and mixtures thereof;
• b) from about 3 to about 25% by weight of an emulsifier component which is soluble in the oil phase and which forms a stable water-in-oil emulsion:
• and
• 2) a water phase comprising from about 0.2 to about 20% by weight of a water-soluble electrolyte:
• 3) a weight ratio of water phase to oil phase of from about 25:1 to about 50:1.

A process for the preparing of a polymeric foam which absorbs aqueous fluids, and which comprises a hydrophilic, flexible, nonionic foam structure of interconnected open cells, said process comprising the steps of:

• A. forming a water-in-oil emulsion from:
• 1) an oil phase comprising:
• a) from about 65 to about 98% by weight of a monomer component comprising:
• i) from about 30 to about 98 % by weight of a polyene having at least 6 carbon atoms and having the formula:
• ##STR7## wherein R.sub.1 are H, halo, amino, cyano, carboxy, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 ester, C.sub.6 -C.sub.12 aryl, C.sub.6 -C.sub.12 heteroaryl, or mixtures thereof, R.sub.2 is H, halo, amino, hydroxy, cyano, carboxy, C.sub.1 -C.sub.16 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 ester, C.sub.6 -C.sub.12 aryl, C.sub.4 -C.sub.12 heteroaryl, or C.sub.2 -C.sub.12 alkenyl;
• ii) from about 2 to about 70% by weight of a crosslinking agent having at least 2 activated double bonds;
• iii) up to about 25% by weight other compatible comonomers;
• b) from about 2 to about 35% by weight of an emulsifier component which is soluble in the oil phase and which forms a stable water-in-oil emulsion;
• and
• 2) a water phase comprising from about 0.2 to about 20% by weight of a water-soluble electrolyte;
• 3) a weight ratio of water phase to oil phase of from about 12:1 to about 100:1.
• 4) an effective amount of at least one polymerization initiator to polymerize monomers in the monomer component;
• B. polymerizing the monomer component in the oil phase of the water-in-oil emulsion to form a polymeric foam material.