Coating processes – Nonuniform coating – Applying superposed diverse coatings or coating a coated base
Patent
1994-11-14
1997-06-10
Beck, Shrive
Coating processes
Nonuniform coating
Applying superposed diverse coatings or coating a coated base
427288, 427337, 106 3128, B05D 136, B05D 310, C09D 1116, C09D 1120
Patent
active
056373546
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a method and to a liquid composition for the production of protected, indelible script on a paper substrate.
BACKGROUND AND SUMMARY OF THE INVENTION
It is well known that ink script can be removed, even if only partially, when it is subjected to suitable chemical or physical action such as, for example, abrasion by bladed instruments or fine points, decolouration with suitable oxidising/reducing agents (including the common "ink-eradicators"), laser light, etc.
It is equally well known that there are recognised solvents or mixtures of solvents which are able to remove script, whatever ink has been used, without etching into the substrate to which it has been applied and hence without leaving any obvious trace of the removal.
In order to protect ink script, particularly but not exclusively on official documents, bank cheques and other similar documents, from accidental or intentional removal, particularly when this is unauthorised, many techniques and devices have been proposed among which are the covering of the script with a transparent film which is extremely adhesive to the paper substrate, which is unaffected by the type of ink used for the script itself and which is insoluble in the solvents for such ink.
However, at least with regard to intentional unauthorised deletion, the techniques and devices adopted up till now have had limited success over time and in the field of application, that is, they have been useful until countermeasures have been found to overcome their protectiveness.
A need has therefore been felt to prevent ink script whether effected manually with a fountain pen, ballpoint pen, felt pen, stamp or the like, or mechanically with a printer, ink jet printer, post marking machine or the like, from being deleted, even only partially, either accidentally or intentionally.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The problem at the root of the invention described above is therefore that of providing a method and a composition which enable script on a paper substrate to resist unauthorised, intentional attempts to remove it.
This problem is solved according to the invention by a method of the type indicated above which is characterised in that it includes the steps of: compound with a high penetrability into the substrate and constituted by molecules having at least two reactive functional groups; the substrate.
The colouring compounds of the invention are selected from those having at least two reactive functional groups in their molecules and having a high power to penetrate the paper substrate, that is which are able to penetrate between the cellulose fibrils forming the structure of the paper substrate by virtue of their low molecular weights and their relatively small molecular dimensions.
Thanks to the presence of at least two reactive functional groups, the colouring compounds of the present invention are able to form polymeric chains within the fibrous matrix of the substrate when treated with suitable oxidising agents.
Multi-functional colouring compounds which are particularly advantageous for the purposes of the invention are the so-called oxidation dyes.
The colouring compounds of the invention may be selected from oxidation dyes which incorporate at least two amino or phenolic functional groups, in particular: diaminobenzenes, diaminotoluenes, naphthols, polyphenols, aminophenols, diaminopyridines and their mixtures.
The diaminobenzenes which are particularly effective in the production of scripts according to the present invention are as follows: p-phenylenediamine; m-phenylenediamine; o-phenylenediamine; N-phenyl-p-phenylenediamine; 2-nitro-p-phenylenediamine; 5-nitro-m-phenylenediamine; 4-nitro-m-phenylenediamine; 4-nitro-o-phenylenediamine; N,N-bis(2-hydroxyethyl)-phenylenediamine; 2-chloro-p-phenylenediamine; 4-chloro-o-phenylenediamine; N, N-dimethyl-p-phenylenedamine; 4-ethoxy-m-phenylenediamine; 2-Nitro-N'phenyl-1,4-benzodiamine; 2,4-diaminodiphenylamine; 2-aminodiphenylamine; 4,4'-diaminodiphenylamine; p-am
REFERENCES:
patent: 3950290 (1976-04-01), Drury, Jr. et al.
patent: 4654082 (1987-03-01), Frilette
patent: 5006127 (1991-04-01), Tennigkeit et al.
patent: 5141556 (1992-08-01), Matrick
Beck Shrive
Parker Fred J.
LandOfFree
Method and liquid composition for the production of indelible sc does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and liquid composition for the production of indelible sc, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and liquid composition for the production of indelible sc will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-763198