5-Phenyl-2,4-pentadienoic acid → Acrylic Acid

In embodiments, the present invention is directed to the preparation of submicron particles comprised of a polyester core encapsulated by a styrene-acrylic acid resin by seed polymerization process, and the economical in situ chemical preparation of toners by the emulsion aggregation/coalescence process without the utilization of the known pulverization and/or classification methods, and wherein in embodiments toner compositions with an average volume diameter of from about 1 to about 25, and preferably from 1 to about 10 microns, and narrow GSD of, for example, from about 1.16 to about 1.26 as measured on the Coulter Counter can be obtained. The resulting toners can be selected for known electrophotographic imaging, printing processes, including color processes, and lithography. In embodiments, the present invention is directed to a process comprised of dispersing a pigment and optionally toner additives like a charge control agent or additive in an aqueous mixture containing an ionic surfactant in an amount of from about 0.5 percent (weight percent throughout unless otherwise indicated) to about 10 percent, and shearing this mixture with a latex of submicron composite particles comprised of a polyester core with a shell of a copolymer of styrene acrylate-acrylic acid of from, for example, about 0.01 micron to about 2 microns in volume average diameter, and which composite particles are obtained from the seed polymerization of monomers, such as acrylic acid, styrene and or methacrylates, a polymerization initiator and a polyester submicron particle comprised of, for example, poly(propylene-terephthalate) or poly(propoxylated bisphenol A-fumarate), in an aqueous solution containing a counterionic surfactant in amounts of from about 1 percent to about 10 percent with opposite charge to the ionic surfactant of the pigment dispersion, and nonionic surfactant in amounts of from about 0 percent to about 5 percent, thereby causing a flocculation of composite particles, pigment particles and optional charge control agent, followed by heating at about 5 to about 40° C. below the shell Tg and preferably about 5 to about 25° C. below the shell Tg while stirring of the flocculent mixture which is believed to form statically bound aggregates of from about 1 micron to about 10 microns in volume average diameter comprised of modified polyester resin, pigment and optionally charge control particles, and thereafter heating the formed bound aggregates about above the Tg (glass transition temperature) of the composite particle. The size of the aforementioned statistically bonded aggregated composite particles can be controlled by adjusting the temperature in the below the resin Tg heating stage. Thus, for example, an increase in the temperature causes an increase in the size of the aggregated particle. This process of aggregating composite particles and pigment particles is kinetically controlled, that is the temperature increases the process of aggregation. The higher the temperature during stirring the quicker the aggregates are formed, for example from about 2 to about 10 times faster in embodiments, and the latex submicron particles are picked up more quickly. The temperature also controls in embodiments the particle size distribution of the aggregates, for example the higher the temperature the narrower the particle size distribution, and this narrower distribution can be achieved in, for example, from about 0.5 to about 24 hours and preferably in about 1 to about 3 hours time. Heating the mixture about above or in embodiments equal to the resin Tg generates toner particles with, for example, an average particle volume diameter of from about 1 to about 25 and preferably 10 microns. It is believed that during the heating stage the components of aggregated composite particle shell fuse together to form composite toner particles. In another embodiment thereof, the present invention is directed to an in situ process comprised of first dispersing a pigment, such as HELIOGEN BLUE™ or HOSTAPERM PINK™, in an aqueous mixture containing a cationic surfactant, such as benzalkonium chloride (SANIZOL B-50™), utilizing a high shearing device, such as a Brinkmann Polytron, microfluidizer or sonicator, thereafter shearing this mixture with a latex of suspended particles of monomers of acrylic acid and styrene, and which latex also contains a polyester resin, and which particles are, for example, of a size ranging from about 0.01 to about 0.5 micron in volume average diameter as measured by the Brookhaven nanosizer in an aqueous surfactant mixture containing an anionic surfactant, such as sodium dodecylbenzene sulfonate (for example NEOGEN R™ or NEOGEN SC™), and a nonionic surfactant, such as alkyl phenoxy poly(ethylenoxy)ethanol (for example IGEPAL 897™ or ANTAROX 897™), thereby resulting in a flocculation, or heterocoagulation of the formed composite particles comprised of a polyester with a shell thereover of a copolymer of styrene-acrylic acid with the pigment particles; and which, on further stirring for about 1 to about 3 hours while heating, for example, from about 35° to about 45° C., results in the formation of statically bound aggregates ranging in size of from about 0.5 micron to about 10 microns in average diameter size as measured by the Coulter Counter (Microsizer II), where the size of those aggregated particles and their distribution can be controlled by the temperature of heating, for example from about 5° to about 25° C. below the resin Tg, and where the speed at which toner size aggregates are formed can also be controlled by the temperature. Thereafter, heating from about 5° to about 50° C. above the resin Tg provides for particle fusion or coalescence of the polymer and pigment particles; followed by optional washing with, for example, hot, for example at a temperature of from about 50° to about 90° C., water to remove surfactant, and drying whereby toner particles comprised of resin and pigment with various particle size diameters can be obtained, such as from 1 to about 20, and preferably 12 microns in average volume particle diameter. The aforementioned toners are especially useful for the development of colored images with excellent line and solid resolution, and wherein substantially no background deposits are present.

1. customIn embodiments, the present invention is directed to the preparation of submicron particles
2. customthe economical in situ chemical preparation of toners by the emulsion aggregation/coalescence process without the utilization of the known pulverization and/or classification methods, and wherein in embodiments toner compositions with an average volume diameter of from about 1 to about 25
3. customcan be obtained
4. additionof dispersing a pigment and optionally toner additives like a charge control agent or additive in an aqueous mixture
5. additioncontaining an ionic surfactant in an amount of from about 0.5 percent (weight percent throughout

ORD record

ord-2a25b3197e1d445b8f23b4d92aa25b2e

Source dataset

uspto-grants-1997_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05604076