Degradable urethane and urethane-urea systems
AssigneeUrethane Systems USA LLC
InventorsMatthew P. Burdzy, Matthew Rasmuson, Rebecca L. Nicholson
Life of this patent
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Abstract
Degradable polymers, including polyurethane and polyurethane-urea compositions, that can be used in aqueous, non-aqueous and dry hot environments as degradable polymers in oil, gas and other applications. Such polymers may be formed from polyurethane-forming compositions, including: (a) an isocyanate component; (b) one or more polyols; (c) a degrading-agent, and (d) optionally, one or more additives. A stoichiometric equivalent of the isocyanate (a) to the polyol (b) may be from about 80 to about 120%.
Claims17
A polyurethane-forming composition, comprising, based on total weight of the polyurethane-forming composition:
- (A) a pre-polymer in a range of from 72 to 84 wt. %, the pre-polymer comprising, in reacted form:
- (a) an isocyanate component comprising toluene diisocyanate (TDI) and/or methylene-bis-(phenyl isocyanate) (MDI);
- and
- (b) a polyol, comprising poly (trimethylolpropane/hexamethylene adipate) glycol, having a number average molecular weight in a range of from 50 to 600;
- (B) a degrading-agent, comprising hexahydrophthalic anhydride (HHPA) and/or maleic anhydride, in a range of from 9 to 20 wt. %;
- and
- (C) a chain extender, comprising a hydroquinone-bis-hydroxyethyl ether (HQEE), dimethylthio-toluene diamine, 1,4-butanediol, and/or 4,4′-methylenebis(o-chloroaniline) (MOCA), in a range of from 6 to 13 wt. %;
- and
- (D) optionally, an additive,
- wherein a stoichiometric equivalent of the isocyanate component (a) to the polyol (b) is in a range of from 80 to 120%,
- wherein the prepolymer has a free monomer content in the range of from 0.05 to 5.0 wt %, based on the total prepolymer weight
- wherein the pre-polymer (A) has an NCO content in a range of from 3.41 to 9.57 wt. %, and
- wherein, the pre-polymer (A), when cured by the chain extender (C), forms a cured urethane network comprising ester groups, and the degrading-agent (B) is mixed in the cured urethane network, and
- wherein, in an aqueous environment, the degrading-agent (B) comprising the hexahydrophthalic anhydride (HHPA) and/or the maleic anhydride hydrolyzes to generate an acid that catalyzes a hydrolysis of the ester groups in the cured urethane network, leading to polymer backbone scission, degradation, and generation of soluble fragments.
Dependencies are inferred from the claim text.