Abstract: Two embodiments of a process for producing concentrated suspensions of polyurea microcapsules especially suitable for manufacturing carbonless copy paper (CCP) are disclosed. Either embodiment can be a batch or continuous process. In the first embodiment, a liquid hydrophobic phase comprising a core material and polyisocyanate at least partially soluble therein is emulsified with an aqueous continuous phase including a polyhydroxylated colloidal stabilizer to form a suspension of microdroplets of the hydrophobic phase. A polyamine such as diethylenetriamine reactive with the polyisocyanate and a catalytic amount of an alkaline base are then added, initiating an interfacial polyaddition reaction at alkaline pH which forms the polyurea microcapsules. The alkaline base is preferably NaOH, KOH, or LiOH; the polyisocyanate is preferably a biuretized or isocyanurate-modified triisocyanate of a lower alkyl diisocyanate; and the polyamine is preferably added in a stoichiometric ratio relative to the isocyanate.

Abstract: Two embodiments of a process for producing concentrated suspensions of polyurea microcapsules especially suitable for manufacturing carbonless copy paper (CCP) are disclosed. Either embodiment can be a batch or continuous process. In the first embodiment, a liquid hydrophobic phase comprising a core material and polyisocyanate at least partially soluble therein is emulsified with an aqueous continuous phase including a polyhydroxylated colloidal stabilizer to form a suspension of microdroplets of the hydrophobic phase. A polyamine such as diethylenetriamine reactive with the polyisocyanate and a catalytic amount of an alkaline base are then added, initiating an interfacial polyaddition reaction at alkaline pH which forms the polyurea microcapsules. The alkaline base is preferably NaOH, KOH, or LiOH; the polyisocyanate is preferably a biuretized or isocyanurate-modified triisocyanate of a lower alkyl diisocyanate; and the polyamine is preferably added in a stoichiometric ratio relative to the isocyanate.

Abstract: A document system having improved image security for preventing or reducing the likelihood of successful alteration of information printed on a document includes a detectable substance is released from ruptured microcapsules onto the document in image areas. The substance that penetrates through the document to form a confirming image on the reverse surface. Another detectable substance of lesser penetrating ability simultaneously may be released onto the document in the image areas. Spreading of the first substance outside the boundaries of the image area created by the second substance may produce a halo effect around the image area. Documents as treated by the methods are disclosed, as well as articles comprising a document to be treated in contact with a sheet coated with the detectable substance. The first substance is microencapsulated, the second substance may or may not be microencapsulated.

Abstract: Methods for preventing or reducing the likelihood of successful alteration of information printed on a document, wherein a detectable substance is released from ruptured microcapsules onto the document in image areas. The substance penetrates through the document to form a confirming image on the reverse surface. Another detectable substance of lesser penetrating ability simultaneously may be released onto the document in the image areas. Spreading of the first substance outside the boundaries of the image area created by the second substance may produce a halo effect around the image area. Documents as treated by the methods are disclosed, as well as articles comprising a document to be treated in contact with a sheet coated with the detectable substance. The first substance is microencapsulated, the second substance may or may not be microencapsulated.

Abstract: A chromogenic mixture capable of forming a black image with zinc-modified phenolic resins is disclosed that includes an orange chromogen, a green or single component black chromogen and a blue, indigo or violet chromogen.