Encapsulated electrostatographic toner material

DETAILED DESCRIPTION OF THE INVENTION There is already known a process for the preparation of microcapsules which comprises forming shells around core materials containing colorant and binder serving as adhesion aid for the colorant to adhere against a support medium.
The encapsulated toner of the invention can be prepared by known processes.
For instance, an interfacial polymerization method can be mentioned as a process employable for the preparation of the microcapsules of the invention.
Examples of other processes employable for the preparation of the microcapsules include an inner polymerization method, a phase separation method, an outer polymerization method, a fusion-dispersion-cooling method, and a coacervation method.
The process for the preparation of microcapsules utilizable in the invention can be carried out by other processes than the above-described processes.
These processes can be employed in combination.
As the materials forming the shell of microcapsules, a variety of materials are known.
These known materials can be employed in the present invention.
Examples of the shell-forming material include proteins such as gelatin and casein; plant gum such as gum arabic and sodium alginate; celluloses such as ethylcellulose and carboxymethylcellulose; condensated polymers such as polyamide, polyester, polyurethane, polyurea, polysulfonamide, polysulfanate, polycarbonate, amino resin, alkyd resin and silicone resin; copolymers such as maleic anhydride copolymer, acrylic acid copolymer and methacrylic acid copolymer; vinyl polymers such as polyvinyl chloride, polyethylene and polystrytene; curable resins such as epoly resin; and inorganic polymers.
Examples of the polymer preferably employable as the shell material include a polyurethane resin, a polyurea resin and a polyamide resin.
Among the known encapsulating methods, the interfacial polymerization method comprising the following process is preferably employed for the preparation of the toner material of the invention.
In the first place, the following two substances are selected: Substance (A) which as such is a hydrophobic liquid or a substance being soluble, miscible or well dispersable in a hydrophobic liquid; and Substance (B) which as such is a hydrophilic liquid or a substance being soluble, miscible or well dispersable in a hydrophilic liquid, which can react with Substance (A) to produce a polymerization reaction product insoluble in either the hydrophobic liquid or the hydrophilic liquid