초록 ▼

This invention relates to control of particle size of solid, discrete, hydrophilic, crosslinked polyurethane particles formed from a composition which comprises (a) a water reactant; (b) a prepolymer comprising at least one isocyanate-capped polyol having a reaction functionality of at least two, th

This invention relates to control of particle size of solid, discrete, hydrophilic, crosslinked polyurethane particles formed from a composition which comprises (a) a water reactant; (b) a prepolymer comprising at least one isocyanate-capped polyol having a reaction functionality of at least two, the total of said polyol present having an ethylene oxide content of at least 40 weight percent before capping; (c) a water-soluble solvent for (b) and (d) when the reaction functionality of (b) is two, a crosslinking agent containing at least three functional groups, the volume ratio of (a):(b) being at least 2:1.

대표청구항 ▼

A process for forming solid, discrete, hydrophilic, crosslinked, polyurethane particles of reduced size which comprises adding (a) a hydrophilic prepolymer comprising an isocyanate-capped polyol or mixture of isocyanate-capped polyols wherein said isocyanate-capped polyol or mixture of polyols has a

A process for forming solid, discrete, hydrophilic, crosslinked, polyurethane particles of reduced size which comprises adding (a) a hydrophilic prepolymer comprising an isocyanate-capped polyol or mixture of isocyanate-capped polyols wherein said isocyanate-capped polyol or mixture of polyols has a reaction functionality greater than 2, the total of said polyol present having an ethylene oxide content of at least 40 weight percent before capping; (b) said prepolymer (a) being dissolved in a water soluble solvent, to (c) an agitated water reactant, the volume ratio of (c):(a) being at least 2:1.