Liquid inks using a gel organosol
Assignee3M Innovative Properties Company
InventorsJames A. Baker, Jai Venkatesan, Wu-Shyong Li, Gay L. Herman, Stewart H. Corn
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Abstract
An organosol comprising a high molecular weight (co)polymeric steric stabilizer covalently bonded to an insoluble, high molecular weight thermoplastic (co)polymeric core is described which has the ability to form a three dimensional gel of controlled rigidity. The gel provides improved liquid ink or liquid electrophotographic/electrographic toner compositions by increasing sedimentation stability of the colorant, without compromising print quality or ink transfer performance. The gel is formed by manipulating the solubility parameter difference between the stabilizer and the solvent to achieve optimum performance of the dispersion.
Claims14
An electrophotographic or electrographic liquid color toner comprising:
- (a) a carrier liqud having a Kauri-butanol number less than 30;
- (b) at least one pigment;
- (c) a charge director;
- and
- (d) a gel organosol comprising a (co)polymeric steric stabilizer having a weight average molecular weight between 50,000 and 750,000 Daltons and a polydispersity less than 15 covalently bonded to a thermoplastic (co)polymeric core insoluble in said carrier liquid and said core having a glass transition temperature between 25° C. and −10° C.,
- wherein the weight ratio of said (co)polymeric steric stabilizer to said thermoplastic (co)polymeric core is between 1/1 and 1/15, and said (co)polymeric steric stabilizer comprises polymerizable organic compounds or mixture of polymerizable organic compounds having an absolute Hildebrand solubility parameter difference between said polymerizable organic compounds or said mixture of polymerizable organic compounds and said carrier liquid between 2.5 and 3.0 MPa½.
An electrostatic liquid toner comprising:
- (a) a carrier liquid having a Kauri-butanol number less than 30;
- (b) a charge director;
- and
- (c) a gel organosol comprising a (co)polymeric steric stabilizer having a weight average molecular weight between 50,000 and 750,000 Daltons and a polydispersity less than 15 covalently bonded to a thermoplastic (co)polymeric core insoluble in said carrier liquid and said core having a glass transition temperature between 15° C. and 55° C., and
- (d) at least one pigment, wherein the weight ratio of said (co)polymeric steric stabilizer to said thermoplastic (co)polymeric core is between 1/1 and 1/15, and said (co)polymeric steric stabilizer comprises polymerizable organic compounds or mixture of polymerizable organic compounds having an absolute Hildebrand solubility parameter difference between said polymerizable organic compounds or said mixture of polymerizable organic compounds and said carrier liquid between 2.3 and 3.0 MPa½.
Dependencies are inferred from the claim text.