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US 4,225,460 AGranted
Latent Lewis acid catalyst system and process
AssigneeMinnesota Mining and Manufacturing Company
InventorRichard G. Newell
Life of this patent
Estimating the term…
Abstract
Microcapsules with liquid fills containing Lewis acid catalysts, catalyst concentrates comprising slurries of the microcapsules in liquid media and a method for preparing the microcapsules and concentrates.
Claims28
A latent catalyst concentrate which comprises a slurry of
- A. rupturable, impermeable microcapsules ranging in size from about 0.1 to 400 microns having
- (1) shell walls of a crosslinked interfacial polyurethane-polyether reaction product of an aromatic polyisocyanate having an equivalent weight of up to about 380 and a functionality of from about 2 to 6, glycerol and a cycloaliphatic polyepoxide having an equivalent weight of from about 70 to 220 and a functionality of from about 2 to 3, and
- (2) liquid fills comprising a Lewis acid-glycerol complex in
- B. a liquid medium selected from aromatic polyisocyanates as defined above and esters of an aromatic carboxylic acid and an alkyl, aralkyl or aryl alcohol, the ester containing up to about 40 carbon atoms.
1 more element
Rupturable, impermeable microcapsules ranging in size from about 0.1 to 400 microns having
- (1) shell walls of a crosslinked interfacial polyurethane-polyether reaction product of an aromatic polyisocyanate having an equivalent weight of up to about 380 and a functionality of from about 2 to 6, glycerol and a cycloaliphatic polyepoxide having an equivalent weight of from about 70 to 220 and a functionality of from about 2 to 3, and
- (2) liquid fills comprising a Lewis acid-glycerol complex.
A method for the preparation of a latent catalyst concentrate which comprises
- (a) dispersing and maintaining discrete droplets of a complex of a Lewis acid with glycerol in a liquid medium selected from aromatic polyisocyanates having an equivalent weight of up to about 380 and a functionality of from about 2 to 6 and esters of an aromatic carboxylic acid and an alkyl, aralkyl or aryl alcohol, the ester containing up to about 40 carbon atoms, and
- (b) adding to said liquid medium a composition comprising an aromatic polyisocyanate as defined above and a cycloaliphatic polyepoxide having an equivalent weight of from about 70 to 220 and a functionality of from about 2 to 3,
- whereby interfacial polycondensation occurs at the droplet surface to form a slurry of rupturable, impermeable microcapsules having shell walls of a crosslinked interfacial polyurethane-polyether reaction product of the aromatic polyisocyanate and the cycloaliphatic polyepoxide and liquid fills comprising the Lewis acid-glycerol complex.
Dependencies are inferred from the claim text.