US3464936A - Anti-smudging printing composition containing a polysaccharide - fluorocarbon derivative combination - Google Patents

Description

Patented Sept. 2, 1969 s 3 rm. (:1. 009a 11/10, 11/06, 11/14 U.S. Cl. 2609 Claims ABSTRACT OF THE DISCLOSURE A printing ink with anti-smearing characteristics comprising a printing ink, and an anti-smudging combination of a polysaccharide and a fluorocarbon derivative.

The present invention relates to a novel process intended to prevent smudging the ink on sheets which have just been printed, by the use of appropriate additives.

In the prior art, to prevent smudging which occurs by simple contact of the sheets with one another, use was first made of insertion sheets absorbing the excess of ink that has not yet dried. The drawbacks of this method are obvious since it leads to additional and considerable handling of sheets of paper Without any benefit other than preventing such smudging. Therefore, it was necessary to unnecessarily double the number of piles of sheets used.

To eliminate the use of inserts, spraying on each printed sheet a mixture of gum arabic dissolved in alcohol has been contemplated. Today, various apparatus are used to spray-dry with suitable blowers, powders, such as starches or calcium carbonate, etc., acting both as an absorbent and insulator.

None of these processes makes it possible, however, to suitably avoid smudging which is intensified the greater the pressure that is exerted on the printed sheets. Therefore, it was previously necessary to limit the height of the piles coming out of printing machines, thus involving additional handling.

Furthermore, despite steps taken to assure a suitable adjustment of the blowers to limit the spraying of the product on the printed parts, a considerable diffusion carries a portion of the powders into the various parts of the printing machine. This then causes a premature wear of these various parts due to unforeseen friction together with undesired powder deposits throughout the machine requiring frequent stops and washing. These idle periods reduce the average speed of the machine, thus reducing optimum performance.

It is the object of this invention to prevent the smudging of newly printed sheets when stacked on one another, following printing by incorporating in the ink composition a polysaccharide compound and a fluorocarbon derivative.

Other objects, features and advantages of the invention will be apparent from the following more particular description of the preferred embodiments of the invention as illustrated.

This novel process applies more particularly, but not exclusively, to printing requiring the use of inks with a base of synthetic resins, mineral or vegetable oils and heavy solvents which are generally designated as fatty inks.

Its application is particularly useful when the printing speed is great, when printing in several colors, and when the paper used is calendered. It applies in a general way not only to typograhic printing or to off-set processes, but also when it is necessary to stack the sheets that have just been printed.

Typical oflset and typographical inks that may be utilized in the present invention are known in the prior art. In volume 11 of the first edition of the Encyclopedia of Chemical Technology, edited by Kirk and Othmer, numerous resins are disclosed as the vehicles for ink compositions. For example, petroleum resins, heat-polymerized rosin, phenolic resins, and chlorinated rubbers are disclosed on pages 153-4.

This invention solves the problems of the prior art by a novel process according to which there is added to the inks, in printing, both in off-set and typographic processes, a compound containing a combination of a polysaccharide compound and a derivative of a fluorocarbon suspended in an agent such as Freon TF (trichlorotrifluoroethane) with or without addition of a WaX-iiS6lf suspended in an agent such as glycerophthalic resin-a silicone and possibly deodorized mineral oil and linseed oil, these novel compounds eliminating smudging and being incorporated either at the time of making the ink, and preferably at the end of fabrication, i.e., before conditioning, or at the very moment of use, the mixing then being carried out either by simple manual or electrical agitation.

By way of example, it is possible to select from the polysaccharide compounds the rice starch and from the fluorocarbon derivatives, a telomer of tetrafluoroethylene in 20% suspension in Freon TF (trichlorotrifluoroethane).

To the first combination it is further possible to add a polyethylene wax with a single molecular weight previously dissolved under heat in a glycerophthalic resin and dispersed after cooling on a mill with the possible addition of linseed oil to facilitate flowing.

As an example, the following Wax composition was prepared:

Parts Glycerophthalic resin (for example, resin R S 73 of R.V.A.) Molecular light-weight polyethylene wax 100 Linseed oil 20 Parts Wax mixture 216 Rice starch 360 Fluorocarbon mixture 360 silicone 11 To improve the homogenization of the composition it is possible to add:

Parts Deodorized mineral oil 36 Linseed oil 36 An electric agitator makes it possible to obtain a perfectly homogeneous emulsion. The novel composition obtained appears in the form of a very clear, gray translucid paste which looks a little like lard.

This composition is then added at a rate of 6 to 9% of the total printing ink composition including ink and antismudging composition, at the moment when the fabrication of the ink is in its final stage, i.e., before its conditioning.

The addition requires the mixture of ink and composition througli a mill, however, this grinding should be light.

It is clear that it would not be going outside the scope of the invention to incorporate the anti-smudging composition thus defined during the very fabrication of the ink.

Finally, the composition can be incorporated in the ink, no longer at the moment of its fabrication, but of its use. All that is required is to perform the mixing either manually or With an electric agitator.

The advantages of this novel process of eliminating smudging are obvious. First of all, it is possible to eliminate all the drawbacks of the old processes by eliminating inserts and apparatus intended to spray an absorbing and insulating product on each printed sheet.

The height of the stacks of printed sheets can be increased by applying the novel process, thus decreasing the losses of time due to frequent handling required in the old processes because of the need for reducing to a minimum the pressure exerted by the weight of the superposed sheets.

At the same time it is possible to use printing supports that have undergone an increased calendering or comprising a synthetic layer that leaves more ink on the surface even with high-speed printing machines operating at more than 5,000 sheets per hour.

On the other hand, the novel compound does not harm the quality of the ink, thus retaining a brillance which is often desired.

Although it is difficult to make a detailed analysis of the successive physical and chemical reactions occurring in the ink and composition, it is thought that during the first phase the starchy products are drawn to the surface and, with the slow evaporation of the trichlorotrifluoroethane, constitute a protection against the ink going onto the following sheet, while the fluorocarbon and silicone products modified the surface tensions between the ink and the surface of the paper in contact.

In another phase, during final polymerization of the ink which passes to the solid state, the wax plays its protective role of an anti-adhesive agent while the trichlorotrifluoroethane, continuing to evaporate, causes a slight gaseous cushion further reducing the risks of smudging even when the pile of papers is sufficiently high to cause a considerable pressure on the lower sheets.

Thus effective anti-smudging compositions are obtained when separate use of each constituent, even in a strong concentration, cannot give comparable results.

It is quite obvious that the anti-smudging composition which has just been given by Way of example, does not limit the scope of the invention which extends not only to similar compounds whose constituent proportions can vary, but also to compounds deriving from said combination by simple substitution of one of the constituents by one of its chemical equivalents. By way of example, the preferred polysaccharide example, could be replaced by any other starch such as wheat or corn starch; the Freon or trichlorotrifluoroethane by another forane; and the glycerophthalic resin by other resins or even by other equivalent vehicles: linseed varnish, for example.

This invention has, for the sake of simplicity, been described in terms of a limited number of materials and embodiments. The inventive concept, however, is to be much broader in that various polysaccharides and fluorocarbon derivatives may be employed for etfectuating similar results. It is to be understood by those skilled in the art that various changes in form, details and in the substances themselves may be made herein without departing from the spirit and scope of this invention.

What is claimed is:

1. In an offset or typographical printing ink containing a base of synthetic resins, mineral of vegetable oils, and a heavy solvent, the improvement which consists of including from about 6 to 9% by weight, based on the total composition, of an anti-smudging composition comprising a combination of a starch, and a telomer of tetrafluoroethylene.

2. A composition as in claim 1 wherein the starch is selected from the group consisting of rice, wheat and corn starches.

3. A composition as in claim 1 wherein the telomer of tetrafiuoroethylene is present in a 20% suspension of trichlorotrifiuoroethane.

4. A composition as in claim 1, comprising additionally in the anti-smudging composition a light-weight wax suspended in glycerophthalic resin.

5. A composition as in claim 4 comprising additionally an oil selected from the group consisting of silicone oil, linseed oil, mineral oil and mixtures thereof.

References Cited UNITED STATES PATENTS 2,347,436 4/ 1944 Root. 2,618,574 11/1952 Pavlic. 3,102,862 9/1963 Green et al. 260-285 3,067,262 12/1962 Brady 26028.5

FOREIGN PATENTS 149,978 2/ 1953 Australia. 903,778 8/ 1962 Great Britain. 514,219 7/1950 Canada.

OTHER REFERENCES Industrial Printing Inks, Larsen, Reinhold Publishing Co., pp. 8495.

WILLIAM H. SHORT, Primary Examiner E. M. WOODBERRY, Assistant Examiner US. Cl. X.R.