Disclosed herein is a toner composition comprising an amorphous polyester resin; a crystalline polyester resin; a styrene acrylate copolymer; an optional wax; and an optional colorant; wherein the amorphous polyester resin comprises a rosin monomer content of from about 10 to about 25 percent rosin monomer based upon the total amount of monomer comprising the amorphous polyester resin. In embodiments, the toner is free of bisphenol A.
Further disclosed is a toner composition comprising a core; at least one shell disposed thereover; wherein the core comprises at least one amorphous polyester resin, at least one crystalline polyester resin; at least one styrene acrylate copolymer, an optional wax, and an optional colorant; wherein the shell comprises at least one styrene acrylate copolymer and an optional wax; and wherein the amorphous polyester resin comprises a rosin monomer content of from about 10 to about 25 percent rosin monomer based upon the total amount of monomer comprising the amorphous polyester resin.
Further disclosed is a toner process comprising contacting an amorphous polyester resin; a crystalline polyester resin; a styrene acrylate copolymer; an optional wax; an optional colorant; and an optional aggregating agent; wherein the amorphous polyester resin comprises a rosin monomer content of from about 10 to about 25 percent rosin monomer based upon the total amount of monomer comprising the amorphous polyester resin; heating to form aggregated toner particles; optionally, adding a shell resin to the aggregated toner particles, and heating to a further elevated temperature to coalesce the particles; and recovering the toner particles.
The vast majority of polymeric materials are based on extracting and processing fossil fuels, a limited resource, potentially resulting in accumulation of non-degradable materials in the environment. Recently, the USDA proposed that all toner/ink have a bio-derived (or sustainable) content of at least 20%. Bio-derived resins are being developed but commercial integration of such reagents into toner and ink remains to be resolved. The terms, “bio-derived resin,” “bio-based resin,” and, “sustainable resin,” are used interchangeably herein and are meant to indicate that the resin or polyester resin is derived from or is obtained from materials or reagents that are obtained from natural sources and are biodegradable, in contrast to materials or monomers obtained from petrochemicals or petroleum-based sources.
Many toners are comprised of at least one amorphous resin. These resins are expensive and are derived from a bisphenol-A based polyester resin. There are customer needs for non-bisphenol-A based toners for applications such as food packaging and there is also a need for lower cost sustainable resins. Additionally, in the future, there may be government procurement requirements for non-bisphenol-A based toners as well as a sustainable requirement of as much as 20% sustainable content by weight of toner.
There are currently known toners comprising crystalline and amorphous polyester. U.S. Pat. No. 9,891,544, which is hereby incorporated by reference herein in its entirety, describes in the abstract thereof toner compositions with toner particles having a core-shell type structure, where the core comprises a first resin comprising a styrene-acrylate copolymer and an amorphous polyester resin, and the shell comprises a second resin comprising beta-carboxyethyl acrylate (β-CEA) in an amount of from about 0.05 pph to about 2.5 pph by weight of the second resin.
U.S. Pat. No. 9,864,291, which is hereby incorporated by reference herein in its entirety, describes in the abstract thereof a hybrid toner includes a core having at least one amorphous polyester resin and at least one crystalline polyester resin, and at least one styrene/acrylate resin, a shell comprising at least one styrene/acrylate resin, at least one wax, and optionally a pigment dispersion, the first modulated differential calorimetry scan of the hybrid toner shows at least two melting point peaks below about 80° C., and the difference between the two melting point peaks is less than or equal to about 15° C.
While these toners are suitable for their intended purposes, the amorphous polyesters utilized in the core comprise bisphenol-A based resins. These toners are not sufficient for those applications wherein non-bisphenol-A based toners are desired or required such as, for example, food packaging.
U.S. Pat. No. 9,791,795, which is hereby incorporated by reference herein in its entirety, describes sustainable resins comprising a rosin or a derivative thereof and lower molecular weight crystalline polyester (CPE) resins which are combined and used in a toner to achieve resin compatibility resulting in lower fixing temperature and higher blocking temperature. These non-bisphenol-A based polyester toner resins include sustainable amorphous rosin based polyester resin.
While certain sustainable resins may be suitable for their intended purpose, the cost of the overall sustainable resin can be as much as 15 to 20 percent higher than comparable non-sustainable resin toners.
Currently available toner compositions and processes are suitable for their intended purposes. However a need remains for improved toner compositions and processes. Further, a need remains for a lower cost non-bisphenol-A based toner suitable for digital packaging applications such as food or pharmaceutical packaging.
The appropriate components and process aspects of the each of the foregoing U. S. Patents and Patent Publications may be selected for the present disclosure in embodiments thereof. Further, throughout this application, various publications, patents, and published patent applications are referred to by an identifying citation. The disclosures of the publications, patents, and published patent applications referenced in this application are hereby incorporated by reference into the present disclosure to more fully describe the state of the art to which this invention pertains.
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