The wax emulsion also replaces some of the microcapsules on the substrate. (JonwaxTM is a registered trademark of S.C. Johnson and Son, Inc., of Racine, Wisconsin.) According to Graves and Tardiff [1999], this process was never commercialized.
2.7 Desensitizing Inks
Frequently, information entered on the top form must be unreadable on certain sections of the form or forms beneath. If the areas on the forms beneath are not needed for other data, two types of obscuring methods can be used. The most common is the "masking" blockout, which entails the printing of a solid block of blue ink over the appropriate areas. The second type of blockout method calls for printing a dense pattern of random lines and blotches suggestive of Chinese characters ("Chinese blockout"). Both methods use the same color ink as the carbonless image color. When the blocked-out areas must remain clear to allow data entry on lower plies, the manufacturer must print a special clear "desensitizing" ink on that area. This desensitizing ink deactivates the carbonless imaging system by not allowing the CF side to react with the color former encapsulated on the CB surface [Mead Corporation 1993]. Desensitizing inks may contain a variety of solvents such as white spirits, kerosene, toluene, alcohols, glycols, ketones, and plasticizers such as dibutyl phthalate, etc. [AEMCP 1985]. Desensitizing inks are sold to industrial printers much like other printing inks [Graves and Tardiff 1999].
Chang [1978] described a patented method of desensitizing CCP when the color developer is a combination of acid clay, phenolic novolac resin, and metal salt of an organic carboxylic acid coated with 10 to 35 parts N-vinylpyrrolidone and about 65 to 90 parts of a free-radical, co-polymerizable compound of a photoinitiator having at least one terminal ethylenic group per molecule. The paper is then subjected to ultraviolet radiation.
Some CCP originates from printing shops that may use different manufacturing sources of CCP in the same manifold. Thus it is extremely difficult to trace the origin of a particular paper. For example, the CF sheet could come from one manufacturer and the remainder of the form from another supplier or manufacturer. In addition, the printer can apply the desensitizing inks to the form [Danish Branch Safety Council for Offices and Administration 1988].
2.8 Summary of Chemical Components of CCP
This section lists the known components of CCP classified as to the microcapsule, color developer, CF coating, etc. The compilation was taken from the scientific literature, patent applications, and manufacturers' submissions.
ADHESIVES FOR BINDING THE VARIOUS COATINGS TO THE PAPER
casein
dextrin
gum arabic
hydroxymethylcellulose
methyl cellulose
polymer lattices (e.g., butadiene/ styrene copolymers or acrylic homopolymers or copolymers)
starch or starch derivatives (wheat or corn)
styrene-butadiene-latex
vinyl acetate
water-soluble polymers (e.g., carboxymethyl cellulose, polyvinyl acetate and polyvinyl alcohol)
