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Erase-Proof Thermal Inks

IP.com Disclosure Number: IPCOM000043475D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Bowlds, PA: AUTHOR [+4]

Abstract

The addition of a natural wax or polyethylene to a thermoplastic resin ink system lowers the melt viscosity so that the ink flows into paper and cannot be cleanly erased. Thermoplastic resins used in printing are selected to be smudge-resistant and not to stick to an adjoining surface when rolled in a spool (often termed blocking). Such resins, especially those deposited from water-borne or latex emulsions, only flow to the paper surface and can be erased by abrasion or adhesive lift-off without leaving a noticeable trace when such resins are the only body of the ink. To achieve erase-proof inks, enough wax or polyethylene is added to a standard thermoplastic-resin ink system to prevent easy erasure, but not so much as to cause problems with pressure sensitivity, color bleeding in the print, and blocking in the ribbon spool.

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Erase-Proof Thermal Inks

The addition of a natural wax or polyethylene to a thermoplastic resin ink system lowers the melt viscosity so that the ink flows into paper and cannot be cleanly erased. Thermoplastic resins used in printing are selected to be smudge- resistant and not to stick to an adjoining surface when rolled in a spool (often termed blocking). Such resins, especially those deposited from water-borne or latex emulsions, only flow to the paper surface and can be erased by abrasion or adhesive lift-off without leaving a noticeable trace when such resins are the only body of the ink. To achieve erase-proof inks, enough wax or polyethylene is added to a standard thermoplastic-resin ink system to prevent easy erasure, but not so much as to cause problems with pressure sensitivity, color bleeding in the print, and blocking in the ribbon spool. An optimum amount generally falls in the range of 40 to 60 percent by weight of solids.

(Image Omitted)

Both ADCOTE 37R345 and ADCOTE 37R929 are from 10 to 20 percent by weight vinyl acetate, with the remainder being ethylene. The melt viscosity at 150OEC is between 1000 and 3000 poise. They are a dispersion of 45% by weight solids in water with minor amounts of dispersants. Both MichemLUBE 150 and MichemLUBE 209 are 25% by weight solid in water with 3 to 5 percent by weight anionic dispersant. MichemLUBE 150 is a blend of paraffin and carnauba wax. MichemLUBE 209 is a blend of carnauba wax and microwax. The wax ingr...