Toner resin with improved rub-off properties

Abstract

This invention relates to toner resins that are synthesized by emulsion polymerization which exhibit good electrical charge stability, adhesion to paper, and rub-off characteristics. The toner resins of this invention are comprised of repeat units that are derived from a vinyl aromatic monomer, an acrylic monomer, and acrylonitrile. These resins are void of repeat units that are derived from acrylic acid. The toner resins of this invention also have a number average molecular weight of greater than 12,000, a weight average molecular weight of greater than 36,000, and a glass transition temperature which is within the range of about 45° C. to about 80° C. The toner resins of this invention are typically made by emulsion polymerization utilizing diacid cycloaliphatic emulsifiers to attain improved adhesion to paper, improved electrical charge stability, a high level of resistance to moisture, and resistance to moisture adsorption (adsorbed moisture is known to neutralize electrical charges). This invention more specifically discloses a toner resin which is comprised of a polymer which is comprised of repeat units which are derived from (a) a vinyl aromatic monomer, (b) an acrylate monomer selected from the group consisting of alkyl acrylate monomers and alkyl methacrylate monomers, (c) acrylonitrile, wherein said polymer is void of repeat units which are derived from acrylic acid. This toner resin can be employed in manufacturing toners that exhibit a high level of rub-off resistance.

Dependencies are inferred from the claim text.